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2TRICAL.  NEWS 


ILLUSTRATED 


LECTRIC  TORPEDO 
DESTROYER 


•SEE  PAGE  10 


LARGEST  CIRCULATION  OF  ANY  ELECTRICAL  PUBLICATION 


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banks,Morse  &  Co.;  now  Con- 
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81  W.  Randolph  St.,  Dept.  295  Chicago,  111. 


State. 


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The  Electrical  Experimeeter 


233  Fulton  Street,  New  York. 
Publisht  by  Experimenter  Publishing  Company,  Inc.  (H.  Gernsback,  President;  S.  Gernsback,  Treasurer;)  233  Fulton  Street,  New  York 


Vol.  V    Whole  No.  49 


CONTENTS  FOR  MAY,  1917 


No.  1 


ELECTRIC  TORPEDO   DESTROYER— Front  Cover  

From  a  painting  by  George  Wall 

A  ONE-MAN  ELECTRIC  SUBMARINE  By  II.  Winfield  Secor 

ELECTRIFYING  THE  AEROPLANE  

THE  AUTOGRAPH  OF  YOUR  HEART  By  Samuel  Cohen 

COMBATING  THE  SUBMARINE  By  H.  Gernsback 

SOURCES  OF  ELECTRICITY   

MAGNETISM  PRODUCES  REMARKABLE  PHOTOGRAPHS.. 

By  F.  F.  Mace 

THE  THERAPY  OF  LIGHT  AND  THE  NEW  "R-RAY"  

By  H.  Rosenthal 

"EDDY  CURRENTS"— A  Scientific  Story  By  C.  M.  Adams 

THE  WASHINGTON'S   BIRTHDAY   RELAY   PRIZE  WINNERS 

By  W.  II.  Kirwan 

ELECTRICITY  AND  LIFE— Second  Paper  

By  Dr.  Frederick  Finch  Strong 

EXPERIMENTAL  PHYSICS — Fourth  Lesson   

Bv  John  T.  Furia,  A.B.,  M.A.,  F.K.S. 
WIRELESS  TELEGRAPHY— THE  MARCONI   HIGH  POWER 


Hi 
12 


IS 

20 


23 


24 

25 


TRANS-OCEANIC  STATIONS  

By  E.  B.  Pillsbury,  Marconi  Wireless  Telegraph  Co. 

HOW  THE  AUDION  REPEATER  REPEATS  

THE    IONIC    RADIO    SYSTEM    AND    THEORY    OF  IONIC 

TUNING  By  Otto  E.  Curtis,  A.M.,  I.R.E. 

RECEIVING  MARCONI  300  K.W.  SPARK  STATIONS  WITH 

OSCILLATING  AUDION   

By  Samuel  Curtis,  Jr.,  R.E.,  U.S.  Navy 

DISTRIBUTED  CAPACITY  AND  ITS  EFFECT  

By  Samuel  Cohen 

A  STUDY  OF  THE  LAW  OF  RESPONSE  OF  THE  SILICON 
DETECTOR   ;  •  •  ;  ■ 

CONSTRUCTOR    DEPARTMENT— AN    ELECTRICAL  PARA- 
DOX OR  SELECTIVE  LAMP  CONTROLLER  

By  Albert  H.  Beiler 

AN  ILLUMINATED  STAGE  SULKY.... By  Harry  S.  Townsend 
A  SIMPLE  ELECTRIC  MOTOR  ATTACHMENT  FOR  PHONO- 
GRAPHS By  R.  U.  Clark,  3d 

EXPERIMENTAL  CHEMISTRY— Twelfth  Lesson   ■■  ■• 

By  Albert  W.  Wilsdon 


26 
30 


31 


34 


3K. 


40 


HE  Radio  Act  of 

states : 

Every  such  license  shall  provide  that  the 
President  of  the  United  States  in  time  of 
war  or  public  peril  may  cause  the  closing 
of  any  station  for  radio  communication 
and  the  removal  therefrom  of  all  radio  apparatus,  or 
may  authorize  the  use  or  control  of  any  such  station 
or  apparatus  by  any  department  of  the  Government, 
upon  just  compensation  to  the  owner. 

We  now  stand  on  the  threshold  of  war;  indeed,  be- 
fore this  issue  is  in  the  hands  of  our  readers  war  will 
have  been  declared,  or  what  is  equivalent,  this  coun- 
try will  be  in  a  state  of  war. 

Let  us  then  be  perfectly  frank  with  each  other,  and 
let  us  face  the  situation  as  it  behooves  upright,  pat- 
riotic, law-abiding  citizens.  The  European  war  has 
taught  us  that  messages  sent  from  secret  radio  plants 
by  spies  have  been  of  priceless  value  to  the  enemy. 
Small  wonder  then  that  hysteric  officials  of  all  the  war- 
ring nations  have  exterminated  every  possible  as  well 
as  impossible  private  wireless  plant  in  their  respect- 
ive countries.  But  to  what  good?  True,  every  sta- 
tionary outfit  has  been  dismantled  or  confiscated  by 
the  warring  Governments,  but  as  always  :  where  there's  a 
will  there's  a  way.  When  the  German  spies  in  England 
and  in  France  found  that  it  was  not  very  healthy  to  op- 
erate their  outfits  in  attics  or  in  house  chimneys — for  a 
sending  outfit  is  soon  located — they  simply  put  their 
radios  in  touring  cars,  cleverly  concealing  the  aerial 
wires  inside  of  the  car  bodies.  The  apparatus  too  were 
easily  concealed,  and  the  English  and  French  were 
outwitted  simply  because  you  cannot  locate  a  moving 
radio  outfit  except  by  pure  chance. 

Which  brings  us  face  to  face  with  the  question : 
Did  it  pay  the  warring  nations  to  kill  the  few  private 
Radio  stations  they  had  before  the  war?  We  are 
honestly  inclined  to  believe  that  far  from  being  an  ad- 
vantage, it  proved  an  actual  disadvantage.  No  one  at 
all  familiar  with  the  technique  of  the  radio  art,  doubts 
for  one  minute  that  if  a  spy  has  the  courage  as  well 
as  the  funds — and  spies  always  have  both — he  cannot 
be  stopt  from  sending  wireless  messages  if  he  elects 
to  do  so.  Working  under  cover  and  by  moving  from 
one  place  to  another,  nothing  will  stop  him. 


If  we  recognize  this  truth 
it  is  to  close  all  privately  owned  radio  stations  during 
the  war.  It  will  doLno  earthly  good  and  can  do  only 
actual  harm.  Now  we  do  hot  wish  to  appear  selfish, 
nor  do  we  wish  to  be  classed  as  unpatriotic.  Very 
much  the  contrary.  If  the  administration,  after  care- 
fully considering  all  the  facts,  decides  to  close  all 
privately  owned  radio  stations  in  this  country,  we 
will  not  as  much  as  raise  a  single  word  of  protest. 
The  administration  knows  what  is  best  for  the  wel- 
fare of  the  country  and  in  time  of  national  peril  we 
would  be  the  last  ones  to  annoy  our  officials. 

But  is  it  not  true  that  our  splendid  body  of  over 
300,000  patriotic  American  Radio  Amateurs,  scattered 
thickly  all  over  the  country,  can  be  of  inestimable 
value  to  the  Government?  Can  not  our  red-blooded 
boys  be  trusted  to  assist  our  officials  in  running  down 
spies,  who  probably  would  not  be  readily  located 
otherwise?  In  our  big  cities  thousands  of  ears  lis- 
ten every  minute  of  the  day  to  what  is  going  on  in  the 
vast  ether-ocean.  Trust  our  very  capable  American 
youths  to  ferret  out  the  senders  of  questionable  sig- 
nals or  strangely  worded  messages.  The  very  multi- 
tude of  these  amateurs  is  a  priceless  protection.  Then 
again  both  our  Army  and  Navy  badly  need  Radio 
operators.  What  other  country  can  furnish  such  a 
vast  army  of  well  trained  and  intelligent  operators 
as  ours,  thanks  to  the  amateurs? 

When  in  1916  the  writer  organized  the  Radio  League 
of  America,  he  incorporated  in  its  statutes  that  every 
member  should  pledge  in  writing  his  station  to  the 
Government.  Up  to  this  moment  the  League  has  for- 
warded to  Washington  thousands  of  such  pledges, 
among  them  every  important  amateur  station  in  the 
country.  These  stations  can  be  used  by  the  admin- 
istration at  a  moment's  notice.  At  least  our  amateurs 
are  fully  prepared. 

Would  it  not  be  questionable  wisdom  to  shut  down 
all  these  stations  that  can  and  will  do  enormously  more 
good  than  possible  harm? 

Let  our  officials  ponder  and  let  them  consider  fairly 
the  facts  in  the  case.    That  is  all  that  we  desire. 

H.  GERNSBACK. 


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3 


4 


THE  ELECTRICAL  EXPERIMENTER 


May,  1917 


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parts,  and  complete  descriptions  and 
prices  of  all  the  latest  electrical  and 
wireless  apparatus 


Upper  Montclair,  N.  J. 


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THE  ELECTRICAL 
EXPERIMENTER 


H.  GERM5BRCK  editor 
H.  W.  5ZZDR  /J55DcmTE  editor 


Vol.  V.    Whole  No.  49 


MAY,  1917 


Number  1 


A  One-Man  Electric  Submarine 


WHILE  Henry  Ford  has  been 
urgently  advocating  the  use  of 
a  one-man  submarine  of  more 
or  less  efficacy,  and  compris- 
ing among  other  things  a  long 
collapsible  pole  extending  from  the  minia- 
ture submarine,  on  the  end  of  which  there 
is  supposed  to  be  placed  a  torpedo  or  bomb 
which  is  to  be  exploded  by  the  operator 
within  the  submersible,  a  number  of  other 
enterprising  inventors  have  been  engaged  on 


By  H.  WINFIELD  SECOR 

ception  of  one  of  these  demons  of  war 
making  its  attack  on  the  hull  of  a  mighty 
Dreadnought,  with  a  magnetic  bomb  prop- 
erly timed  to  explode  a  few  minutes  after 
its  attachment,  in  order  to  give  the  opera- 
tor of  the  one-man  submersible  sufficient 
time  in  which  to  get  far  enough  away  from 
his  victim  to  protect  himself. 

In  the  first  place,  it  is  the  inventor's  idea 
to  make  up  these  miniature  submersibles 
of  about  the  same  size  as  the  modern  auto- 


at  two  hundred  horse-power  for  the  above 
range,  if  the  craft  is  to  make  a  speed  of 
42  knots  or  approximately  50  miles  per 
hour.  In  the  event  that  the  navigator  of 
such  a  submersible  should  have  to  make  a 
detour  in  order  to  get  back  to*  the  mother- 
ship  or  to  his  shore  base,  it  would  be  ad- 
visable to  equip  the  boat  with  an  auxiliary 
gasoline  engine  as  shown  in  the  accom- 
panying illustration.  'Most  probably  un- 
der ordinary  conditions,  the  operator  of 


The  One-man  Electric  Submarine  Here  Shown  in  Detail  and  Also  in  Action  Has  Considerable  Promise.  It  Can  Dart  Thru  the  Water  at 
Torpedo  Speed  (50  miles  per  hour)  When,  Having  Attached  Its  Magnetic  "War-head"  Containing  the  Gun-cotton  and  a  Time  Fuse  to  the 
Hull  of  an  Enemy  Vessel,  It  Can  Easily  and  Quickly  Make  Its  Escape   at    Mile-a-minute   Speed.     It   Should    Prove   Ideal   for   Coast  and 

Harbor  Defense. 


a  similar  yet  somewhat  different  problem. 
One  of  the  most  promising  of  these  designs 
for  a  one-man  submarine  is  that  of  Mr. 
■Eric  R.  Lyon,  the  engineer  who  was  respon- 
sible for  the  mastodonic  two-hundred-foot 
high  electric  gyro-cruiser  featured  in  our 
February,  1916,  issue. 

The  accompanying  illustration  shows  a 
detailed  view  of  a  one-man  electro-me- 
chanical submersible  along  the  lines  laid 
down  by  Mr.  Lyon,  and  also  an  artist's  con- 


Harbor  Defense 

mobile  torpedo,  or  measuring  say  25  feet 
long  by  3  feet  in  diameter.  This  com- 
pares approximately  with  the  dimensions 
of  the  latest  type  U.  S.  torpedo'  with  a 
range  of  ten  thousand  yards  or  5.7  miles. 
When  comprest  air  is  utilized  for  propul- 
sion, the  air  being  stored  in  the  tank  at  two 
thousand  pounds  pressure  to  the  square 
inch,  the  comprest  air  engine  used  in  the 
modern  torpedo  (and  which  could  be  adap- 
ted to  the  one-man  submersible)  is  rated 


this  new  war  engine  would  have  no  trouble 
in  getting  back  to  his  base  of  operation  by 
means  of  the  comprest  air  equipment.  It 
has  been  claimed  by  Mr.  Ford  and  other  in- 
vestigators that  it  is  now  possible  to  op- 
erate a  gasoline  engine  under  water  by 
means  of  special  absorption  apparatus  at- 
tached to  the  exhaust  manifold  of  the  gas- 
oline or  other  engine,  and  that  this  means 
of  propulsion  can  be  attached  to  submarine 
war  vessels.    If  such  is  the  case,  then  it 


6 


THE  ELECTRICAL  EXPERIMENTER 


May,  191 7 


"ELEVATING"  CENTRAL. 

The  upper  stories  of  the  West  Palm 
T.each  Telephone  Company's  office  in  Flor- 
ida, which  has  just,  had  two  floors  added 
to  it,  was  the  scene  of  a  remarkable  en- 
gineering feat  recently. 

Under  the  new  arrangement  it  became 
necessary  to  remove  the  big  switchboard, 
at  which  the  operators  sit  and  make  the 
connections  that  enable  people  to  communi- 
cate with  each  other  on  an  infinite  var- 
iety of  subjects,  important  or  affectionate 
or  merely  frivolous,  from  the  third  to  the 
fourth  story.  The  move  was  made  in  the 
following  simple  but  effective  manner. 

A  platform  composed  of  two  pieces  of 
4x6  timber,  on  which  was  laid  a  floor  of 


2x12  planks,  was  built  under  the  heavy 
switchboard — wide  enough  to  accommodate 
the  operators'  chairs  around  the  edge  of 
the  board.  Slings  were  then  placed  about 
the  whole  business,  to  which  a  tackle  and 
three  heavy  differential  blocks,  each  cap- 
able of  handling  a  weight  of  four  tons, 
attached  to  a  sling  of  log  chains  fastened 


to  a  heavy  beam  at  the  top  of  the  fifth 
story. 

The  switchboard,  with  the  girls  seated 
at  it,  and  still  carrying  on  their  work, 
was  hoisted  thru  a  hole  in  the  floor  of  the 
fourth  story. 

The  work  was  carried  on  without  a  hitch, 
and  the  girls  remained  suspended  until 
the  floor  had  been  rebuilt  under  the  switch- 
board. There  was  not  the  slightest  inter- 
ruption to  business  from  first  to  last  dur- 
ing the  ascent.  Nor  did  the  subscribers, 
talking  over  the  switchboard,  suspect  in 
their  wildest  utterings,  that  "Central" 
Switchboard  Girls — chewing  gum  and  all — 
were  moving  skyward,  angel-like,  all  the 
while. 


Right: — At   Last!     Central's  Eleva- 
tion    Completed.      No  interruption 
in  Traffic  and  the  Girls  Are  10  Feet 
Nearer  Heaven. 


will  mean  that  the  one-man  submarine  will 
become  all  the  more  practicable. 

Coming  down  to  the  means  whereby  this 
novel  engine  of  war  is  to  be  used  in  car- 
rying out  offensive  operations,  we  see  upon 
looking  over  the  detail  drawing  that  in  front 
of  the  submarine  there  is  a  detachable  war- 
head in  the  form  of  a  steel  cap  which  fits 
against  the  parabolic  nose  of  the  subma- 
rine very  tightly.  This  war-head  contains 
the  usual  quantity  of  gun-cotton  or  other 
high  explosive.  Suitable  quick-acting  mag- 
netic clutches  enable  the  operator  to  in- 
stantly release  the  entire  war-head  ait  any 
desired  moment. 

This  submersible  not  only  carries  two  dis- 
tinct forms  of  prime  mover,  but  also  car- 
ries the  necessary  gas  tanks  to  supply  a 
set  of  ultra-powerful  oxy-acetylene  flame 
nozzles,  suitably  disposed  about  the  for- 
ward part  of  the  vessel  on  the  exterior,  and 
by  means  of  which  the  operator  can  burn 
his  way  thru  any  ordinary  submarine  net 
entanglement. 

This  feature  is  one  of  the  latest  scien- 
tific discoveries  and  involves  the  operation 
of  an  oxy-acetylene  flame  under  water, 
which  is  made  possible  by  blowing  a  stream 
of  comprest  air  around  the  gas  nozzle,  and 
in  this  way  forming  a  flame  pocket  in  the 
•water  so  to  speak. 

Mr,  Lyon  is  very  enthusiastic  on  this  par- 
ticular innovation,  and  has  drawn  plans  for 
a  one-man  submarine  which  utilizes  an  ex- 
tra powerful  and  especially  contrived  set  of 
these  high  power  oxy-acetylene  nozzles  with 
which  to  burn  a  hole  thru  the  bottom  of 
a  Dreadnought,  causing  it  to  founder  soon- 
er or  later. 


Among  the  other  interesting  features  of 
the  idea  here  pictured  we  find  a  collapsible 
periscope  which  may  be  folded  down  into 
a  suitable  pocket  provided  in  the  top  of  the 
hull,  and  attached  to  which  there  is  an  air 
tube  and  also  a  (distress)  rocket  shute. 
When  running  submerged,  a  special  air 
machine  is  used  to  supply  the  necessary- 
oxygen  to  the  navigator.  A  powerful  elec- 
tric searchlight  is  fitted  to  the  front  of  the 
detachable  war-head  and  by  means  of  the 
small  periscope  shown  the  operator  can  see 
ahead  at  a  considerable  distance  ufider  the 
water.  A  compact  but  powerful  battery  is 
contained  in  the  war-head  which  can  sup- 
ply sufficient  energy  to  energize  the  electro- 
magnets which  hold  the  explosive  chamber 
to  the  hull  of  the  enemy  war  vessel  once 
the  operator  has  managed  to  approach  close 
enough  to  accomplish  this  result. 

The  war-head  also  carries  a  special  elec- 
tric time  switch,  which  functions  a  few 
minutes  after  the  war-head  has  been  at- 
tached magnetically  to  the  hull  of  the  ene- 
my vessel,  and  which  causes  an  electric 
spark  to  detonate  the  gun-cotton  charge. 

It  has  been  argued  by  a  number  of  naval 
experts  that  the  One-man  Submarine  is 
doomed  to  failure  for  several  different  rea- 
sons. This,  however,  does  not  seem  to  be 
the  case  so  far  as  we  can  see,  and  provid- 
ing the  submersible  is  nroperly  designed  in 
its  details. 

Let  us  take  a  concrete  case  for  example 
to  show  how  the  Lyon  one-man  ship  de- 
stroyer would  go  about  its  task. 

Assuming  that  these  engines  of  destruc- 
tion, of  which  there  would  be  most  prob- 
ably several  in  each  attack  to  make  doubly 


sure  that  the  enemy  would  not  escape,  have 
been  despatched  either  from  a  fort  or  oth- 
er point  on  the  coast,  or  from  a  mother-ship 
several  miles  *-.stant  from  the  enemy,  the 
intrepid  navigator  of  the  50-mile-an-hour 
submarine  starts  forth  on  his  perilous  jour- 
ney. With  only  his  periscope  exposed  and 
at  a  distance  of  several  miles,  it  is  well 
known  that  a  periscope  projecting  a  foot  or 
so  above  the  water  presents  an  almost  im- 
possible target  for  ordinary  gun-fire,  and 
moreover,  as  the  vessel  darts  forth  on  its 
way  and  as  the  range  decreases  between 
himself  and  the  enemy,  the  buoyancy  and 
submerging  tank  motor-pumps  are  manip- 
ulated so  that  only  occasional  sightings 
are  made  with  the  periscope.  It  thus  be- 
comes very  problematical  whether  the  ene- 
my could  hit  the  submarine.  Also  at  a 
distance  of  say  one  mile,  and  in  accordance 
with  standard  submarine  maneuvering  the 
submarine  officer  then  proceeds  to  take  ac- 
curate sightings  of  the  enemy  both  with 
regard  to  the  range  and  the  direction  geo- 
graphically, after  which  he  submerges  and 
may  proceed  at  high  speed  at  a  depth  of 
fifteen  to  twenty  feet  below  the  surface  of 
the  water  (the  same  as  modern  torpedoes) 
and  in  a  little  over  a  minute  or  so,  'and 
providing  he  has  gaged  the  enemy's  posi- 
tion accurately,  he  will  find  himself  in  the 
vicinity  of  the  bottom  of  the  hull.  Owing 
to  the  high  speed  possible  with  this  minia- 
ture submarine,  built  like  a  torpedo,  it 
should  be  possible  for  the  navigator  (in 
the  event  that  he  does  not  strike  his  mark, 
when  he  has  gone  the  range  calculated  up- 
(Continaed  on  page  47) 


May,  1917 


THE  ELECTRICAL  EXPERIMENTER 


Electrifying  the  Aeroplane 


ELECTRICITY  is  being  rapidly  in- 
troduced in  the  new  art  of  Aero- 
nautics as  the  illustrations  herewith 
tend  to  testify.  The  greatest  de- 
velopment in  the  art  of  flying  is 
■the  aerial  limousine  or  so-called  Autoplanc 
illustrated  in  Fig.  1,  which  was  exhibited 
.at  the  recent  aeroplane  show  held  in  New 
York  City.  This  aeroplane  is  built  in  the 
form  of  an  automobile  limou- 
sine and  equipt  with  three 
•planes  for  the  sustaining  sur- 
face. Aside  from  its  perfect 
-mechanical  features  its  electri- 
cal equipment  is  exceedingly 
interesting,  as  the  engine  is 
automatically  started  by  means 
■of  an  electric  motor  installed 
•exactly  the  same  as  the  mod- 


the  minimum  air  speed  has  been  reached. 
It  is  mounted  in  any  convenient  position 
where  the  air  flow  is  unobstructed. 

The  stallemometer  is  adjustable  for  any 
desired  air  speed,  depending  on  the  aero- 
plane on  which  it  is  installed.  When  the 
predetermined  speed  is  reached,  an  electric 
contact  is  closed  in  the  stallemometer,  clos- 
ing the   circuit   thru   an   indicating  lamp 


I  Fig.     3.      Electrically  \ 

I  operated  "Incidence 

m  Indicator"    for  show- 

I  ing    best   gliding    and  } 

J|  climbing  angles.  1 


Fig.  2.  The  electric 
"Stallemometer"  warns 
the  aviator,  when  his  ma- 
chine is  approaching  a 
stalling  condition  by  indi- 
cating that  the  minimum 
air  speed  has  been 
reached. 


at  a  dangerous  angle.  The  white  lamp  sig- 
nals whenever  the  pilot  dives  at  too  steep 
an  angle.  The  green  light  indicates  the  best 
climbing  angle.  Being  of  low  voltage  as 
well  as  low  current  consumption,  the  lights 
can  be  operated  on  a  dry  battery,  encased 
in  metal  and  installed  wherever  most  con- 
venient. The  signals  are  regulated  by  a 
vane  operated  by  the  air  stream. 

The  lamp  bank  container  is 
seen  in  the  background.  Each 
lamp  is  equipt  with  the  proper 
colored  screen  and  each  con- 
nected to  the  required  contacts 
enclosed  in  the  incidence  indi- 
cator chamber.  The  lead  wires 
are  led  thru  one  of  the  support- 
ing tubes. 

Aviators  wishing  to  know  at 


Fig.  1.  The  latest  in  flying  machines 
— the  "Autoplane."  It  is  an  aerial 
limousine. 


Fig.  4.  Dead-beat 
"Clinometer"  which 
shows  angle  of  aero- 
plane with  the  earth. 


Fig.  5.  The  "Sperry  Automatic  Pilot"  which,  by  means  of  elec- 
tric driven  gyroscopes,  serves  to  control  and  maintain  an  aero- 
plane in  any  desired  position:  the  pilot  may  drop  bombs,  etc. 


-em  automobile  engine  electric  starter.  The 
■engine  develops  100  horsepower  and  drives 
a  four-bladed  propeller  place  at  the  rear. 
The  interior  lighting  is  aecomplisht  entire- 
ly by  electric  lamps  and  its  ignition  is  of 
the  very  latest  electrical  design.  Altho  it 
-may  seem  that  the  machine  was  not  made 
for  speed,  yet  it  has  a  speed  range  of  sixty- 
five  miles  per  hour  and  can  si  ;tain  a  weight 
of  710  pounds.  It  can  carry  two  passen- 
gers and  a  pilot. 

The  stallemometer  illustrated  in  Fig.  2 
i's  an  electric  instrument  devised  to  warn 
the  aviator  when  his  machine  is  approach- 
ing a  stalling  condition  by  indicating  that 


mounted  on  the  instrument  board  stationed 
in  front  of  the  pilot. 

An  incidence  indicator  increases  the  effi- 
ciency of  an  aeroplane  by  warning  the  avia- 
tor before  he  stalls  and  by  enabling  him  to 
get  the  best  climbing  and  gliding  angles  out 
of  his  machine. 

The  transmitter  of  the  Incidence  Indica- 
tor in  Fig.  3,  is  mounted  on  a  forward  strut 
so  as  not  to  interfere  with  any  part  of  the 
plane.  The  lamp  bank  or  indicator  is  on 
the  instrument  cowl,  always  visible  to  the 
pilot  observing  other  essential  instruments. 
The  red  light  warns  the  aviator  before  he 
stalls  as  well  as  when  he  begins  climbing 


any  time  the  correct  'fore  and  'aft  posi- 
tion of  the  machine,  with  reference  to  the 
horizontal,  can  read  it  on  the  scale  of  the 
dead-beat  clinometer  illustrated  at  Fig.  4. 

The  operation  of  this  instrument  is  sim- 
ple. Whenever  the  clinometer  is  tipt  for- 
ward or  backward  by  the  motion  of  the 
plane,  this  movement  is  registered  on  a  scale 
mounted  on  a  wheel  which  is  damped  by 
floating  in  a  liquid. 

If  the  aeroplane  tips  forward,  the  scale 
moves  upward,  indicating  in  degrees  below 
the  zero  line  the  exact  angle.  If  the  ma- 
chine tips  backward,  the  scale  moves  down- 
( Continued  on  pane  54) 


8 


THE  ELECTRICAL  EXPERIMENTER 


May,  1917 


The  Autograph  of  Your  Heart 

By  SAMUEL  COHEN 


ONE  of  the  most  important  mech- 
anisms of  the  human  body  is  the 
Heart.  Its  action  in  health  and 
disease  has  been  the  subject  of 
attention  by  numerous  prominent 
physicians  in  all  parts  of  the  world,  par- 


Showing  How  the  Extremely  Sen- 
sitive Electrical  Apparatus  Is 
Connected  up  to  Patient  in  Scien- 
tifically Determining  Just  How 
the  Heart  Beats  and  Why.  The 
Apparatus  Used  for  this  Meas- 
urement Is  Known  as  the  "Elec- 
trocardiograph."   (Fig.  2.) 

ticularly  those  interested  in  fighting  heart 
disease,  the  most  unrelenting  malady  with 
which  one  can  be  stricken.  Yet  it  has 
been  said  that  15,000  to  20,000  school  chil- 
dren in  New  York  alone  are  suffering 
from  it. 

In  view  of  its  most  important  function 
and   delicate   structure,   cure,  by   way  of 
operation,  is  usually  im- 
possible.    Therefore,   the  — — 
only  thing  left  is  to  care- 
fully study  the  heart,  lo- 
cate the  trouble  and  de- 
termine  the   reasons  for 
this  trouble.    A  first  aid 
in  this  direction  is  a  bio- 
graphical  history   of  the 
patient. 

The  rapid  growth  of 
this  disease,  and  the  rapid  — — — - 
advancement  of  science  ~ ^^^^™^^~ 
has  led  to  the  devel- 
opment of  a  new  instrument  called  the 
Electrocardiograph.  This  instrument  is 
really  a  modified  Einthoven  galvanomet- 
er, consisting  of  a  very  powerful  mag- 
netic field  produced  by  an  electromag- 
net and  excited  by  a  constant  direct  cur- 
rent, such  as  the  current  given  by  a  stor- 
age battery.  A  very  short  air  gap  is  made 
between  the  poles  of  the  magnet  and  in 
this  powerful  field  a  fine  quartz  filament 
or  fiber  is  stretched.  Delicate  adjusting 
means  are  provided  for  controlling  the 
tension  of  this  wire.   (See  Fig.  1.) 

A  small  diafram  is  placed  on  the  center 
of  this  which  closes  two  small  holes  that 
extend  thru  in  each  pole  piece.  These 
holes  are  the  condensing  microscopes  and 
the  projecting  microscope  to  focus  a  fine 
beam  of  light  to  strike  a  moving  photo- 
graphic film.  If  the  wire  is  slightly  dis- 
placed by  the  passage  of  an  electric  cur- 
rent thru  it,  it  will  naturally  displace  the 
small  diafram  and  in  turn  permit  the  fine 
beam  of  light  to  pass  thru  the_  openings 
and  strike  the  film  placed  opposite  to  the 
projecting  lamp  throwing  out  the  fine  beam 
of  light.  It  will,  therefore,  be  seen  that 
by  displacing  the  quartz  wire  in  certain 
movements  that  a  record  will  be  made  on 
the  film  accordingly.  This  quartz  filament 
is  connected  to  a  Wheatstone  bridge  of 
proper  dimensions  and  also  to  special 
terminals  which  are  connected  to  the  pa- 


tient whose  heart  is  to  be  examined.  These 
terminals  are  three  in  number  and  are 
made  of  German  silver  plates,  each  of 
them  being  fitted  with  binding  posts  con- 
nected to  the  leads,  connecting  the  plates 
with  the  sensitive  galvanometer  and 
Wheatstone  bridge  circuit. 
Two  of  the  plates  are  se- 
cured to  the  arms  of  the 
patient,  while  the  third 
terminal  is  strapt  around 
the  left  ankle.  Proper 
care  is  taken  to  see  that 
the  electrical  connection 
between  the  body  and  the 
terminal  is  of  low  resist- 
ance and  for  this  purpose 
a  wet  cloth  which  is  sat- 
urated with  a  20  per  cent 
salt  solution  is  placed  be- 
tween the  foot  and  plate 
and  again  the  cloth  is 
wrapt  about  the  plate. 
The  Wheatstone  bridge 
circuit  is  balanced  so  that 
the  resistance  of  the  elec- 
trical path  between  ter- 
minals is  constant,  and 
this  is  obtained  when  the 
quartz  string  or  filament 
of  the  galvanometer  is  in 

a  zero  position. 

It  is  evident  that  a  slight  addition  of 
current  to  the  galvanometer  circuit  will 
cause  a  displacement  af  the  filament,  which 
is  recorded  on  the  film.  Since  the  contrac- 
tion of  the  heart  creates  an-  electric  cur- 
rent as  found  by  various  scientists,  and 
as  the  intensity  of  this  current  depends 


tN  the  present  article  we  have  one  of  the  most  interesting  and  startling 
revelations  of  what  medical  science,  plus  electricity,  is  doing  to  bring 
about  a  clearer  understanding  of  our  bodily  actions.  Herewith  is  pre- 
sented a  true  electrical  record  of  a  patient's  heart,  which  shows  the  fluc- 
tuations occurring  just  before  and  at  the  critical  moment  when  life  ceased 
to  exist.    In  other  words,  the  patient  died. 


upon  the  intensity  of  the  heart  contrac- 
tion, it  is  therefore  obvious  that  the  fine 
quartz  wire  will  be  displaced  a  certain 
amount  by  the  generation  of  current  by 
the  heart.  With  the  contraction  wave, 
the  electric  potential  spreads  over  the  heart 
and  thus  the  galvanometer  records  the 
heart  beat  and  also  indicates  the  origin 
and  path  by  which  the  current  spreads. 

An  exact  replica  of  the  apparatus  used 
in  recording  the  pulsation  of  the  heart  is 
illustrated  in  Fig.  2.  This  shows  the  ap- 
paratus in  actual  use  and  also  how  the 
various  electrodes  are  secured  to  the  pa- 
tient. This  photograph  was  taken  at  the 
time  a  record  was  actually  being  made  of 
the  condition  of  the  patient's  heart.  The 
sensitive  galvanometer  is  seen  at  the  left, 
while  the  beam  of  light  is  derived  from  a 
powerful  arc  projector  stationed  at  the  ex- 
treme left,  but  not  shown.  The  instrument 
at  the  extreme  right  is  the  photographic 
film  apparatus.  The  film  is  driven  at  a 
definite  and  uniform  speed  ly  an  electric 
motor  mounted  at  the  bottom  of  the  ma- 
chine. This  instrument  is  placed  in  exact 
line  with  that  of  the  telescope  of  the  gal- 
vanometer pole-piece.  The  resistance  box 
is  shown  on  the  shelf  of  the  galvanometer 
table. 

The  instrument  traces  its  indication  of 
conditions  in  the  heart  by  curves  on  the 
photographic   film.     These  heart  pictures 


are  as  characteristic  as  finger  prints  or 
photographs.  No '-'two  individuals'  hearts, 
beat  alike,  and  the  electrocardiograph,  by 
its  extremely  delicate  registration  of  the 
contraction  of  the  muscle,  readily  shows 
the  most  minute  difference. 

A  remarkable  story  of  a  dying  heart  is 
told  by  the  accompanying  curves  registered 
by  the  electroca  diograph.  The  graphs  il- 
lustrating this  remarkable  story  are  shown 
in  the  third  figure,  and  these  were  taken 
by  Dr.  R.  H.  Halsey,  of  New  York  City. 

The  records  here  reproduced  form  an 
almost  complete  electrocardiographic  rec- 
ord of  the  heart  b  t  during  the  last  move- 
ments of  the  patient's  life.  Tho  death 
was  expected,  yet  its  actual  advent  was 
much  earlier  than  had  been  anticipated ; 
the  transition  from  life  to  death  was 
abrupt.  The  w  ning  of  change  is  to  be 
found  in  the  lengthened  conduction  inter- 
val and  in  the  changed  ventricular  com- 
plex of  Fig.  5.  That  fibrillation  of  the 
ventricles  was  riot  the  immediate  cause  of 
death  is  clear  from  Fig.  6,  taken  when  the 
usual  signs  of  life  were  in  abeyance ;  the 
heart  was  profoundly  affected,  and  the  pa- 
tient past  all  possible  hope  of  recovery 
before   fi  rillation  ensued. 

The  record  was  obtained  from  a  female 
patient  thirty  yea  s  of  age,  suffering  from 
broncho-pneumonia   of  both   lower  lobes. 
The  curves  were  taken  one  after  the  other 
in  quick  succession  and  are  described  in 
this  order.    In  Fig.  1  the  frequency  of  the 
heart  is  75.    The  duration  of  the  diastole* 
varies  from  0.2  sec,  to  less  than  0.1  sec, 
and  is  non-rhythmic.    The  up-stroke  of  P 
is  quicker  than  the  downstroke.    The  con- 
duction time  is  within  the 
normal  limits  of  0.2  sec. 
T  is  upward  in  its  direc- 
tion and  of  considerable 
excursion.    In  the  second 
figure,   the    frequency  of 
the  heart  is  80.   There  are 
the  same  vibrations  in  the 
duration   of  the  diastole. 
The  electrocardiograph 
Figures  3,  4  and  5  show 
— __ _     the   different  frequencies 
of  rne  heart  at  different 
periods.    In    curve  5, 
the  frequency  of  contraction  of  the  heart 
appears  to  have  dropt  to  45,  while  asso- 
ciation of  auricle  and  ventricle  is  still  pres- 
ent.    The   conduction   time   is   0.4   sec. ; 
double  the  time  in  the  earlier  record.  Dur- 


Close  View  ot  the  Einthoven  String  Gal- 
vanometer Used  in  Actually  Measuring  and 
Analyzing  the  Infinitesimal  Electrical  Cur- 
rents Produced  by  the  Human  Heart  at 
Every  Beat.  Did  You  Know  that  Your 
Heart  Was  a  Dynamo?    (Fig.  1.) 

ing  the  very  brief  interval  between  the 
taking  of  Figs.  5  and  6,  convulsive  gasps 
and  a  slow  contraction  of  the  skeletal  mus- 
cles  occurred.    In  Fig.  6,  the  change  is  re- 

*  Diastole  is  the  period  of  rest  between  con- 
tractions of  the  heart. 


May,  1917 


THE  ELECTRICAL  EXPERIMENTER 


(Above) — Figures  1  to  4. 

markable,  and  the  frequency  of 
the  ventricle  has  increased  to  63 
per  minute.  The  remaining  com- 
plexes vary  in  their  detailed  form, 
but  are  similar  in  general  outline. 
In  Fig.  7,  there  are  no  evidences 
of  coordinate  ventricular  contrac- 
tion. The  remaining  records  are 
similar;  in  Fig.  13,  all  movement 
ceased  permanently,  the  patient 
having  died. 

When  the  heart  takes  a  sudden 
jump  to  the  fast  rate,  stops  sud- 
denly and  returns  to  the  normal 
rate,  a  typical  curve  is  made  as  in- 
dicated above.  This  condition  is 
called  a  "flutter."  The  auricles  of 
the  heart  sometimes  contracting 
three  hundred  times  a  minute  and 
the  ventricles  only  one  hundred 
and  fifty  times  a  minute ! 

By  the  use  of  the  electrocardio- 
graph and  a  stethoscope  connected 
with  a  microphone,  the  sounds 
made  by  the  contractions  of  the 
heart  are  recorded  with  curves  in- 
dicating the  rhythm  so  that  the 
exact  point  in  the  heart  cycle  of 
various  normal  and  abnormal 
sounds  may  be  recorded. 

Electrocardiograph  records 
showing  the  action  of  the  heart  under  cer- 
tain treatment  may  be  made  and  sent  to 
physicians  in  various  parts  of  the  world, 
who  by  interpreting  the  curves  can  ob- 
tain information  of  great  value  in  the 
treatment  of  their  own  patients. 

In  order  to  standardize  such  records,  the 
tension  of  the  galvanometer  quartz  wire  is 
adjusted  so  that  a  current  of  one-thou- 
sandth of  a  volt  will  deflect  the  filament 
to  such  an  extent  that  its  shadow  projected 
on  the  recording  film  will  move  one  cen- 
timeter in  both  directions !  Since  the  wire 
is  set  to  move  a  definite  amount  for  a 
known  voltage  of  current,  the  deflection 
shows  the  amount  of  current  that  caused 
it.  The  heart  of  the  average  individual 
causes  a  deflection  which  indicates  the  pas- 
sage of  a  current  of  approximately  one  to 
two  one-thousandths  of  a  volt.  Thus  it  is 
known  that  it  would  require  the  heart 
beats  of  thousands  of  persons  to  generate 
enough  current  to  light  an  incandescent 
lamp. 

In  conclusion  it  may  be  said  that  the 
conditions  of  the  human  heart  can  now  be 
studied  with  far  greater  accuracy  than 
was  ever  possible  heretofore,  thanks  to  the 
Electrocardiograph. 


RADIUM  AND 
CANCER. 

"The  Other  Side  of 
the  Radium  Cure"  is  the 
title  of  an  article  by 
Dr.  J.  H.  Blaisdell,  in 
the  Boston  H  erald. 
This  is  of  such  great 
interest  that  we  give  it 
below,  as  many  of  our 
readers  have  undoubted- 
ly read  the  recent  re- 
port of  the  Director  of 
the  Crocker  Cancer  Re- 
search Commission 
printed  in  these  col- 
umns. 

"Newspaper  interpre- 
tation of  medical  sub- 
jects, vital  to  the  inter- 
ests of  the  health  of  the 
community,"  says  Dr. 
Blaisdell,  "should  be  pe- 
culiarly  conservative 
and  well  advised.  To 
me  your  editorial  com- 
ments on  radium  in  can- 
cer   on  Wednesday 


(Above) — Figures   5  to  9. 

MAN  SWALLOWED 
$20,400  WORTH  OF 
RADIUM. 

In  an  article  treating 
on  the  use  of  "Radium  in 
Surgery  and  Gynecol- 
ogy" in  Radium,  Dr. 
John  M.  Lee  relates  a 
peculiar  accident  which 
haopened  in  applying  a 
valuable  tube  of  radium. 
Sarcomata  and  epithel- 
iomata  of  the  tonsils  in 
several  patients  have 
yielded  excellent  re- 
sults. In  one  of  mv 
'first  cases,  a  vigorous, 
powerful  man,  with 
more  money  than  judg- 
ment, jerked  his  hea  I 
backward  thru  the  sup- 
porting hands  of  the 
nurse,  and  at  the  same 
time  yanked  the  mucous- 
smeared  and  slippery 
braided  silk  thread  out 
of  my  hand,  just  as  I 
was  about  to  seize  the 
tubes    in    the  pharynx 


morning  of  this  week  seem  especially  open 
to  criticism  on  this  score. 

"Briefly  stated,  your  summing  up  of  the 
findings  of  the  Crocker  cancer  commission 
of  Columbia  University  unqualifiedly  placed 
radium  in  the  discard  as  a  'cure,'  damned 
it  with  faint  praise  as  a  palliative,  and 
noted  with  the  cheerful  abandon  of  'life 
opportunity  given  the  medical  profession  to 
make  'the  patient's  condition  worse  than 
if  he  had  been  left  alone.'  Such- is  the 
pessimistic  side  of  the  picture  based  on 
truth  but,  unfortunately  for  your  readers, 
only  half  the  truth.  Simply  because  rad- 
ium cannot  act  as  a  'cure'  in  inoperable 
or  hopeless  cases  of  systemic  cancer  is 
no  reason  why  readers  should  be  instructed 
to  regard  it  as  a  discarded  fad  to  the  utter 
disregard  of  countless  cases  of  early  mal- 
ignant disease  that  this  remedy  has  saved. 

"Point  out  rather  to  your  readers  (re- 
ferring to  the  editor  of  the  Boston  Her- 
ald )  the  significance  of  the  recent  pur- 
chase of  many  thousand  dollars'  worth  of 
radium  by  the  -luntington  Hospital  of 
Boston,  as  an  example  of  how  useful  it  is 
in  experienced  hands.  Tell  them  of  its 
curative  effects  beyond  that  of  any  other 
remedy  in  epitheliomas  or  cancers 
of  the  skin.  Lay  your  emphasis 
on  how  radium  can  absolutely 
prevent  cancers  of  the  skin  if 
people  could  be  taught  to  have  the 
early  pre-cancerous  possibilities 
such  as  keratoses,  warts,  moles, 
etc.,  removed  before  degeneration 
starts.  By  such  statements  it 
seems  to  me  you  would  be  doing 
the  greater  services  to  the  com- 
munity and  more  rightly  interpre- 
ting the  findings  of  the  Crocker 
Cancer  Commission  on  Radium." 


with  forceps,  and  swallowed  175 
milligrams  of  radium  in  three 
well-screened  tubes.  He  refused 
immediate  gastrotomy,  and  the 
tubes  were  past  thru  the  alimen- 
tary canal  at  the  average  rate  of 
nine  inches  per  hour.  No  injury 
followed  and  he  said :  "None  of 
the  crowned  heads  of  Europe 
have  anything  over  me  in  luxuri- 
ous repasts,  for  I  have  had  the 
only  distinction  of  the  consump- 
tion of  a  $20,400  meal." 


(Below) — Figures  10  to  13. 


TrR" 


/V~~~\f  


firm 


The  Above  Electrocardiograph  Records,  Numbered  1  to  13  Con- 
secutively, Represent  the  Most  Remarkable  Scientific  Analysis 
of  Just  What  Does  Happen  In  a  Person's  Heart  Shortly  Before 
and  at  the  Exact  Period  When  Life  Ceases  to  Exist,  or  Death. 
By  Inspecting  These  Charts  of  the  Heart's  Variations  During 
the  Last  Moments  of  the  (Female)  Patient,  a  Victim  of  Broncho- 
Pneumonia  One  Can  See  How  the  Heart  Started  to  Fluctuate 
Progressively,  Finally  Stopping  Action  at  the  Right  End.  (Fig.  13.)  i 


IO 


THE  ELECTRICAL  EXPERIMENTER 


May,  1917 


Combating  the  Torpedo 


WAR  after  all  is  but  a  game  of 
chess.  The  greatest  generals 
of  modern  civilization  realized 
this  so  profoundly  that  every 
one  of  them  had  been  at  one 
time  a  good  chess  player.  In  war,  as  in 
chess,  luck  plays  but  an  insignificant  part. 
Given  like  equipment,  the  general  who  has 
the  greatest  strategical  ability  will  win, 
whether  it  be  in  the  field  or  on  the  chess- 
board. Also,  if  both  opponents  can  suf- 
ficiently anticipate  each 
other's  moves,  no  one  will  — — — — 
win.  In  this  case  there 
will  be  a  stalemate,  as  it 
has  existed  for  over  two 
years  in  France.  But 
stalemates  necessarily  al- 
ways denote  equal  strength 
of  both  opponents  and  a 
stalemate  often  turns  out 
to  be  a  negative  victory, 
for  it  is  certainly  not  de- 
feat. 

The  present  submarine  —— — — — 
warfare  is  no  exception 
to  the  rule  of  comparing 
war  to  chess,  for  the  simple  reason  that  it 
is  an  uneven  game — all  the  powerful 
pieces  are  on  the  U-Boat's  side  and  no 
Queen,  Rooks  and  Knights  on  the  other 
side  of  the  board  to  defend  the  King.  At 
least  there  was  no  defense  worthy  of  the 
name  up  to  a  few  months  ago. 

But  science,  as  always,  is  progressing 
steadily  and  soon  the  submarine  will  have 
found  its  master,  or  at  least  its  equal,  with 
which  to  stalemate  it. 

Let  me  first  correct  a  popular  illusion. 
Almost  every  one  of  us  thinks  or  speaks 
of  the  "deadly  submarine,"  when,  as  a  mat- 
ter of  fact,  the  submarine  itself  is  not  only 
not  deadly  but  a  very  weak  contrivance  at 
best.  Point  a  3-inch  gun  at  it  and  it  will 
vanish  instantly.  Send  a  20-foot  motor 
boat  chaser  against 
its  periscope  and  the 
"deadly"  submarine 
at  once  becomes 
deader  than  the  pro- 
verbial doornail. 

It  is  the  subma- 
rine's deadly  weapon 
— t  h  e  torpedo — that 
has  so  far  out-gener- 
aled  the  cleverest 
brains  and  has  given 
the  greatest  statesmen 
untold  sleepless 
nights.  To  fight  the 
submarine  itself  is 
comparatively  easy, 
given  good  guns  and 
good  gunners  on 
board  the  attackt 
ship,  providing  of 
course  that  the  enemy 
submarine  command- 
er is  foolish  enough 
to  expose  his  craft  too 
much  above  the 
waves. 

Several  methods 
have  been  adopted  of 
late  to  combat  th? 
submarine,  none  of 
which  have  been 
great  successes. 

First,  we  have  the  smoke-screen — per- 
haps one  of  the  most  effective  schemes  de- 
veloped lately.  By  means  of  dense  vol- 
umes of  chemical  smoke,  blown  around  the 
ship  by  powerful  exhaust  pumps,  the  ship 
is  enveloped  almost  completely  in  a  fog- 
like screen  and  it  becomes  a  very  difficult 
target  for  a  torpedo.    The  ship's  bow,  how- 

This  article  appeared  originally  in  the  Sunday 
"New  York  American"  of  April  15t/i. 


By  H.  GERNSBACK 

ever,  is  nearly  always  exposed.  The  oth- 
er method  is  to  protect  the  ship  with 
strong  torpedo  netting  suspended  by  means 
of  booms  from  the  ship.  The  torpedo  upon 
striking  the  net  is  thus  rendered  harmless, 
as  it  never  reaches  the  ship,  unless  the  net- 
ting is  made  of  rope  and  the  torpedo  is 
equipt  with  cutting  blades.  In  that  case 
the  torpedo  will  strike  the  ship  and  blow 
it  up. 

But  the  one  great  drawback  of  the  net- 


OUR  readers  will  find  much  food  for  thought  in  this  interesting  article. 
While  the  idea  may  not  effectively  stop  enemy  submarines  from  tor- 
pedoing every  merchant  vessel,  we  feel  confident  that  we  have  shown 
a  fairly  practical  way  to  obtain  satisfactory  results. 

Mr.  Gernsback  is  donating  his  invention  to  the  Nation  and  he  wishes 
it  to  be  understood  that  he  will  not  require  to  be  paid  royalties  or  any 
other  considerations  from  Amercian  ship  owners.  Foreign  ship  owners 
are  not  included  in  the  above. 


ting  is  that  it  is  almost  impossible  to  use  it 
on  a  fast  moving  ship.  It  is  too  cumber- 
some and  most  important  of  all  it  greatly 
retards  the  speed  of  the  ship,  due  to  the 
excessive  friction  of  the  netting  against  the 
water. 

The  next — and  poorest — means  to  com- 
bat the  submarine  is  our  widely  advertised 
mounting-guns-on-a-ship  scheme.  Xo  sub- 
marine commander  in  his  right  senses  ex- 
poses more  than  one  or  two  feet  of  his 
periscope  when  making  a  torpedo  attack. 
And  remember  no  torpedo  attack  is  ever 
made  at  a  closer  range  than  800  yards. 
Two  thousand,  and  even  four  thousand, 
yards  are  very  common  nowadays.  Im- 
agine a  gunner  on  even  a  slightly  rolling 
ship  trying  to  hit  an  object  one  foot  high 


Patents  Pending. 

Top  View  of  Ship  with  its  Ten  "Motor-Torpedoes"  Which  Operate  Independently  from  the 
Steamer.  An  Approaching  Enemy  Torpedo  Is  Blown  Up  or  Thrown  Off  Its  Course  by  Explod- 
ing One  or  More  of  the  Little  Motor-Torpedoes  at  the  Critical  Moment.  Note  that  the 
Modern  Torpedo  Leaves  the  Submarine  in  a  Curved  Line  After  Which  Its  Gyroscope 
Rights  It  on  the  Final  Straight  Run.  (Fig.  1.) 

and  less  than  six  inches  in  diameter,  at  a 
distance  of  3,000  yards !  It  simply  can't 
be  done.  Scoring  a  hit  under  such  cir- 
cumstances is  pure  chance,  and  don't  for- 
get that  the  periscope  itself  does  not  stand 
still  either.  It,  too,  bobs  up  and  down.  In 
fact,  at  such  a  distance  it  is  often  almost 
invisible. 

Mounting  guns  on  merchant  vessels  nev- 


ertheless is  of  distinct  use,  in  so  far  as 
the  guns  will  keep  a  submarine  at  a  re- 
spectful distance  and  prevent  the  U-Boat 
commander   from  attacking  the  ship  by 
means  of  his  own  gun-fire.    But  mounting 
guns  on  ships  will  never  prevent  a  torpedo 
from  finding  its  deadly  mark.    You  can't 
shoot  at  a  torpedo — the  bullet  is  too  small 
and  the  modern  torpedo  making  43  knots, 
i.e.,  50  miles  an  hour,  moves  far  too  fast. 
After  much  thought  on  the  subject,  I 
came    to   the  conclusion 
—     that  in  the  torpedo  itself 
we    have     an  effective 
weapon    to    combat  the 
torpedo,    strange    as  it 
may  sound  at  first.  You 
can  combat  a  gun  with 
another  gun,  and  you  can 
combat  one  rifle  with  an- 
other, as  well  as  you  can 
fight  one  aeroplane  with 
another. 

Why    not    combat  the 
—— — — — — —      torpedo  with  another  tor- 

™"^™*"" ™""^^~  pedo?  It  is  all  very  pos- 
sible and  simple  if  you 
know  how ;  as  a  matter  of  fact  the  idea 
struck  me  so  favorably  that  I  decided  to 
apply  for  patents  in  all  civilized  countries. 

Several  navy  experts  have  reported  fav- 
orably on  the  idea,  and  while  up  to  this 
writing  no  ships  have  been  equipt  with  the 
device,  I  would  not  be  at  all  surprised  to 
see  the  idea  put  into  practise  very  shortly. 

Our  front  cover  and  the  two  accompa- 
nying drawings  illustrate  the  idea  clearly. 

The  underlying  idea  of  the  whole  scheme 
is  that  it  takes  the  torpedo  an  appreciable 
length  of  time  between  the  instant  of  be- 
ing released  from  its  submarine  and  the 
moment  it  strikes  the  attacked  ship.  Tak- 
ing the  closest  range  at  which  a  torpedo 
can  be  fired  as  800  yards — and  it  cannot  be 
fired  much  closer  successfully — this  gives 
a  time  of  55/100th  or 
over  half  a  minute  to 
cover  that  distance, 
short  as  it  is.  Tak- 
ing the  average  range 
of  2,000  yards,  it  will 
take  the  torpedo  l3A 
minutes  before  it  will 
strike.  These  figures 
are  for  the  latest  type 
Bliss-Leavitt  torpedo 
making  43  knots,  i.e., 
50  miles  an  hour. 

But   a  torpedo, 
whether   it   runs  on 
the    surface    of  the 
water  or  submerged 
below  it,  always  leaves 
a    very  noticeable 
"wake"  in  its  course. 
Remember  a  torpedo 
is  propelled  solely  by 
comprest   air,   c  o  m- 
prest  up  to  2,200  lbs. 
per  square  inch.  This 
air  must  of  necessity 
come  to  the  surface 
of  the  water,  as  the 
torpedo  runs  over  its 
course.    The  disturb- 
ance created  thus 
gives  rise  to  the  al- 
most snow-white  wake,  which  is  very  no- 
ticeable from  a  distance.    Thus  a  man  sta- 
tioned on  a  ship  readily  sees  the  wake 
as   it   comes  nearer  and  nearer  and  he 
can  gage  pretty  accurately  just  where  the 
torpedo  will  hit.  '  Escape  for  the  compara- 
tively slow-moving  ship  is  impossible,  even 
if  the  engines  were  reversed  instantly.  The 
vessel's  momentum  would  still  be  so  great 


May,  191 7 


THE  ELECTRICAL  EXPERIMENTER 


that  the  deadly  torpedo  would  surely  find 
its  mark. 

My  proposed  means  of  rendering  enemy 
torpedoes  ineffective  is  as  follows :  Fig.  1 


sees  to  it  that  the  speed  of  each  torpedo 
keeps  up  exactly  with  the  speed  of  the  ship, 
for  there  should  never  be  a  drag  on  the 
cables.     This  is  readily  accomplished  by 


Detonafing 
snitches 


Speed  con 
trot  ond 
reversing 
rheostat 


Volt  and  ammeters 
Snitches 

Cable  reeling  . 
drum  A  motor  I 

1 

if*  % 

Dec/r, 


Hoisting  Davit 


Flexible  cable  to  itiip 


Todynomo  / 

Electric  Coble  to  other 

mres  torpedoes  on* 

right  side  of  ship 

Forward  Most  Torpedo 
Switchboard 


Explosive  Charge 
Motor-  Torpedo 


© 


Propeller  motor 

Rudder  control  motor 


Rudders 
Propeller 


Concrete  Ballasted  tree/ 


means  of  rheostats,  one  for  each  torpedo. 
By  cutting  in  more  or  less  resistance  the  12 
H.P.  motor  can  be  made  to  run  faster  or 
slower  and  the  torpedoes  are  thus  easily 
controlled  as  to  speed.  By  means  of  a 
double-pole,  double-throw  switch  the  little 
l/2  H.P.  motor  is  revolved  in  either  direc- 
tion, thus  effectively  steering  the  little  craft 
so  that  it  will  always  keep  at  a  distance 
of  some  fifty  feet  from  the  mother  ship. 
On  the  control  board  furthermore  there  is 
a  switch  connected  to  a  storage  battery 
from  which  wires  are  run  thru  the  cable 


PatentB  Fending. 

Fig.  2.   The  Electrically  Propelled  and  Electrically  Steered  Gernsback  "Motor- Torpedo."    It  Is  from  15  to  20 
Feet  Long  and  Runs  Independently  from  the  Mother  Ship.    An  Operator  High  Up  on  the  Ship's  Mast 
Blows  Up  the  Motor-Torpedo  by  Electric  Contact    as  Soon  as  the  Enemy  Torpedo  Approaches  Within 
15    Feet.      Both    Torpedoes    are    Thus  Destroyed. 

shows  the  plan  view  of  an  average  steamer, 
600  feet  long.    On  each  side  we  observe 
five  (or   more)    independent,  electrically 
propelled    torpedoes.     Fig.    2   shows  the 
construction  of  the  torpedo  itself.  Briefly, 
it  is  built  along  the  shape  of  the  regulation 
torpedo  and  measures  from  15  to  20  feet 
in  length  and  from  3  to  5  feet  in  diameter. 
It  has   a  12   horse-power  electric  motor 
geared  to  the  propellers  and  there  is  also 
a  little  J/2  H.P.  motor  geared  to  the  rudder 
with  which  to  steer  the  torpedo.    Most  of 
the   space   between   the  war- 
head and  the  motors  is  taken 
up  with  the  usual  charge  of 
gun-cotton.    This  torpedo,  un- 
like its  other  brethren,  has  a 
heavily  weighted  keel  to  pre- 
vent it  from  rolling  over,  for 
reasons  which  will  be  appar- 
ent later.    On  the  back  of  the 
torpedo    is    mounted    a  steel 
mast-like  structure  thru  which 
the  control  cable  passes.  This 
cable  then  rui.s  to  the  deck  of 
the  ship  over  pulley  arrange- 
ments   as    shown   in  Fig.  2. 
There  is  also  a  drum  to  take 
up  the  slack  of  the  cable,  or 
to  play  out  more  cable  should 
the  occasion  aris~.    The  cable 
then  runs  up  on  the  mast  into 
a  special  turret  located  as  high 
up  as  is  feasible.    Here  we 
find   one   or  more  operators 
sitting  in  front  of  the  electric 
control-board.    All  the  cables 
from  the  star-board  side  tor- 
pedoes run  into  the  forward 
mast-turret,    while    all  the 
cables  from  the  port  side  tor- 
pedoes run  into  the  rear  mast- 
turret.    Thus  each  set  of  op- 
erators watches   out   for  the 
safety  of  his  side  of  the  ship. 

All  of  the  torpedoes  are 
painted  in  such  a  color  that 
the  operator  can  watch  them 
readily  and  guide  their  indi- 
vidual course.  Sitting  at  the 
control-board    the  operator 


into  the  torpedo  and  thence  into  the  de- 
tonator placed  in  the  gun-cotton  charge, 
Fig.  2.  Throwing  this  switch  will  blow 
up  our  torpedo. 

The  war  action  of  the  idea 
is  as  follows :  Our  ship  has 
left  New  York  with  all  of  the 
motor  torpedoes  hoisted  out 
of  the  water  and  lashed  se- 
curely to  the  decks.  The  mo- 
ment the  need  arises  the  tor- 
pedoes are  lowered  quickly 
into  the  water  and  the  control 
operator  starts  the  machinery 
of  each  torpedo,  and  in  less 
than  two  minutes  all  of  them 
should  be  running  smoothly, 
fifty  to  seventy  feet  distant. 

Suddenly  the  outlook  scan- 
ning the  waters  with  his  bi- 
noculars  sights  the  periscope 
of  an  enemy  submarine  and 
in  less  than  a  minute  later  our 
operator  observes  the  rapidly 
lengthening  wake  of  a  death- 
carrying     enemy  torpedo. 
High  up  as  he  is  located,  he 
calculates  that  in  less  than  two 
minutes    the    enemy  torpedo 
will  strike  somewhere  between 
his   motor   torpedoes    Nos.  1 
and  2  (see  Fig.  1).    By  cut- 
ting in   resistance  into  rheo- 
stat   No.    1,    he  immediately 
slows  up  motor  torpedo  No.  1 
thereby  intercepting  the  path 
of  the  enemy  torpedo.    Or  if, 
for  certain  reasons,  he  wishes 
to  use  his  motor  torpedo  No. 
2,  he  leaves  No.  1  in  its  original  course 
but  by  cutting  out  more  resistance  from 
rheostat  No.  2,  he  speeds  up  the  latter 
with  the  result  that  it  advances  faster  than 
the  ship  and  in  this  case  as  well  it  will 
intercept  the  course  of  the  enemy  torpedo. 

Suppose  he  decides  to  use  motor  torpedo 
No.  1.  He  has  nearly  two  minutes  to 
jockey  it  for  position  and  he  will  find  little 
trouble  to  intercept  the  course  of  the  hos- 
tile engine  of  death.  His  eyes  glued  to 
the  enemy  torpedo  (or  to  its  wake),  his 
{Continued  on  page  68) 


An  Actual  Photoqraoh  of  the  "Wake"  of  a  Modern  Torpedo. 
Particular  Torpedo  Ran  About  10  Feet  Under  Water,  Having 


Photo  by  Paul  Thompson. 

Attention  Is  Called  to  the  Fact  That  This 
Been    Fired    by   a   Submerged  Submarine. 


12 


THE  ELECTRICAL  EXPERIMENTER 


May,  1917 


Sources  of  Electricity 


WtilLE  most  of  us  are  familiar 
possibly  with  several  sources 
of  electrical  energy,  we  do  not 
always  stop  to  think  of  the 
many  possible  sources  which 
are  little  known,  especially  to  the  layman. 
We  have  endeavored  in  the  present  article, 
and  with  the  aid  of  the  accompanying  full 
page  illustration,  to  describe  the  principal 
known  sources  of  electricity. 

Static  Electricity :  This  form  of  elec- 
tricity is  that  which  we  see  when  we  stroke 
pussy's  fur  in  a  dark  room  and  obtain  a 
spark  when  the  hand  is  withdrawn  from 
contact  with  the  fur ;  or  again,  we  may 
obtain  the  same  form  of  electric  shock  or 
discharge  by  rubbing  together  two  dissimi- 
lar substances,  such  as  a  stick  of  sealing 
wax  with  a  silk  handkerchief,  after  which 
it  will  be  found  that  the  electrified  stick  of 
sealing  wax  will  attract  bits  of  paper  or 
small  pith  balls.  A  rapidly  moving  belt  oitcn 
develops  a  considerable  amount  of  static 
or  frictional  electricity,  which  will  tend  to 
discharge  to  earth  whenever  possible.  One 
may  often  stand  near  such  a  belt,  and  by 
holding  the  knuckles  or  even  the  ends  of 
the  fingers  near  the  belt,  a  heavy  static 
discharge  will  take  place  between  the  belt 
and  the  fingers,  the  electric  charge  passing 
thru  the  body  to  earth. 

One.  of  the  usual  and  practical  sources 
of  such  electricity  is  the  static  machine 
(Fig.  1)  and  when  the  handle  of  such  a 
machine  is  turned,  one  or  more  insulating 
discs  are  rapidly  rotated,  and  by  succes- 
sive intensification  of  a  very  slight  electric 
charge  existing  on  the  tin-foil  sectors  of 
these  plates  before  the  machine  is  started 
up,  a  surprisingly  powerful  static  discharge 
is  rapidly  built  up.  This  will  manifest 
itself  in  the  form  of  an  electric  spark, 
which  crashes  across  the  gap  between  two 
metal  balls  on  the  side  of  the  machine. 
There  are  many  other  sources  of  static 
electricity  but  the  whole  phenomenon  is 
practically  the  same. 

Contact  Electricity :  It  was  Volta  who 
showed  that  the  contact  of  two  dissimilar 
metals  in  the  air  produce  opposite  kinds  of 
electrification,  one  becoming  positively,  and 
the  other  negatively  electrified.  There  has 
been  considerable  discussion  as  to  the  exact 
action  occuring  in  the  production  of  elec- 
trical currents  by  the  contact  of  two  dis- 
similiar  methods  in  air,  and  for  a  long 
time,  says  Silvanus  P.  Thompson,  the  ex- 
istence of  this  electrification  by  contact  was 
denied,  or  rather  it  was  declared  to  be  due 
(when  occurring  in  voltaic  combinations) 
to  chemical  actions  going  on ;  whereas,  the 
real  truth  is  that  the  electricity  of  contact 
and  the  chemical  action  are  both  due  to 
transfers  of  electrons  between  the  sub- 
stances under  the  peculiar  actions  of  forces, 
about  which  very  little  is  known  with  cer- 
tainty as  yet. 

Volta  found  that  the  difference  of  elec- 
tric potential  between  the  different  pairs  of 
metals  was  not  all  equal,  as  while  zinc 
and  lead  were  respectively  positive  and  neg- 
ative to  a  slight  degree ;  zinc  and  silver 
proved  to  be  positive  and  negative  to  a 
much  greater  degree.  The  voltage  ob- 
tained by  the  contact  between  zinc  and 
carbon  is  1.09  volts. 

The  phenomena  of  electrical  currents 
produced  by  the  contact  of  dissimilar 
methods  is  illustrated  by  Fig.  2.  A  dif- 
ference of  potential  or  voltage  is  also  pro- 
duced by  the  contact  of  two  dissimilar 
liquids.  It  has  been  found  that  a  liquid 
and  a  metal  in  contact  exhibit  a  difference 
of  potential  or  voltage,  and  if  the  metal 
tends  to  dissolve  into  the  liquid  chemical, 
there  will  be  an  electro-motive  force  acting 
from  the  metal  toward  the  liquid.    A  hot 


metal  placed  in  contact  with  a  cold  piece 
of  the  same  metal,  also  produces  a  differ- 
ence of  potential,  and  lastly  Sir  Joseph  J. 
Thomson  has  demonstrated  that  the  sur- 
face of  contact  between  two  non-conduct- 
ing substances,  such  as  sealing  wax  and 
glass,  is  the  seat  of  a  permanent  difference 
of  potential. 

Galvanic  Electricity :  The  primary  bat- 
tery is  generally  denned  as  one  in  which 
electrical  energy  is  produced  by  chemical 
means,  without  having  to  charge  the  battery 
from  dynamo  or  other  source  originally. 
The  simplest  form  of  such  a  battery  com- 
prises a  glass  or  other  vessel  containing 
sulfuric  acid  and  water,  or  any  other  oxi- 
dizing acid  solution,  and  in  which  are  im- 
mersed two  clean  metal  strips,  one  of  zinc 
and  one  of  copper.  Most  of  us  are  prob- 
ably familiar  with  the  common  form  of 
primary  battery  used  in  American  prac- 
tise for  ringing  bells  and  operating  medi- 
cal coils  in  the  form  of  the  well-known 
dry  cell,  or  with  the  zinc-copper-salam- 
moniac  cell.  In  the  zinc-copper-acid  cell 
above  mentioned,  a  continuous  flow  of 
electricity  may  take  place  thru  a  wire  or 
apparatus  which  connects  the  two  plates. 
When  such  a  current  passes,  the  zinc  strip 
may  be  seen  to  waste  away,  or  decompose 
by  the  electro-chemical  action  taking  place, 
and  its  consumption,  in  fact,  furnishes  the 
energy  required  to  drive  the  current  thru 
the  cell  and  the  connecting  wire  or  ap- 
paratus. In  such  a  cell,  the  zinc  strip 
forms  the  positive  electrode  or  negative 
terminal,  while  the  copper -strip  forms  the 
negative  electrode  or  positive  terminal. 
Such  a  cell  gives  about  one  volt  potential. 

Fig.  3  shows  a  unique  form  of  primary 
battery  known  as  the  Hauck  Circulation 
battery.  In  this  battery,  composed  of  sev- 
eral cells,  the  electrolyte  or  solution  is 
caused  to  pass  from  a  tank  above  the  bat- 
tery cells,  thence  thru  the  first  or  higher 
cell,  then  thru  the  next  lower  container,  etc 
This  is  a  chromic  acid  battery  with  car- 
bon and  zinc  electrodes.  The  zincs  are  lo- 
cated in  the  rectangular  porous  cups  while 
the  two  carbon  plates  are  outside  of  the 
porous  cups,  all  the  space  between  porous 
cup  and  carbon  plates,  as  well  as  between 
the  carbon  plates  and  glass  vessel  being 
filled  out  with  small  carbon  pieces.  In  the 
porous  cup  there  is  a  sulfuric  acid  electro- 
lyte, while  the  carbons  stand  in  chromic 
acid.  As  the  latter  is  caused  to  circu- 
late continuously  from  one  battery  to  the 
next,  all  polarisation  is  done  away  with 
and  we  obtain  a  very  steady  and  powerful 
current.  The  battery  illustrated  gives  6 
volts  and  60  amperes  and  can  be  used  to 
charge  storage  batteries,  run  fans,  or  elec- 
tric lamps.  It  is  one  of  the  best  chromic 
acid  batteries  ever  designed. 

Electricity  from  Gases :  Fig.  4  shows  the 
famous  Grove  Gas  Battery  invented  in  l£39. 
It  shows  how  two  gases  are  used  to  pro- 
duce an  electric  current.  The  two  glass 
tubes  contain  platinum  strips  coated  with 
spongy  platinum.  The  glass  bottle  contains 
acidulated  water  in  which  the  two  glass 
tubes  plunge,  as  seen.  One  of  the  tubes 
contains  oxygen,  the  other  hydrogen,  as 
will  be  noted  the  gases  make  contact  with 
the  acidulated  water.  If  we  connect  the 
two  terminals  with  a  galvanometer  we  will 
observe  an  electric  current,  the  oxygen  fur- 
nishing the  positive,  the  hydrogen  the  nega- 
tive pole  of  the  battery.  Incidently  we 
note  that,  as  we  consume  current,  the  liquid 
rises  in  the  two  glass  tubes,  but  twice  as 
fast  in  the  hydrogen  tube  as  in  the  one 
containing  the  oxygen.  As  each  tube  is 
identical  with  the  other,  except  for  the 
gases,  it  follows  that  the  current  can  be 
due  only  to  the  gases.    Also  different  gases 


produce   different  voltages  and  currents. 

Pyro -Electricity  or  Electricity  from  Crys- 
tals :  In  the  accompanying  Fig.  5,  we  have 
several  methods  by  which  minute  quantities 
of  electricity  are  produced  from  crystals, 
when  these  are  manipulated  in  a  specific 
manner.  Certain  crystals,  when  they  are 
heated  or  cooled,  exhibit  electrical  charges 
at  certain  regions  or  poles,  and  such  crys- 
tals which  become  electrified  by  heating  or 
cooling  are  said  to  be  pyro-electric.  One 
of  the  principal  crystals  which  manifest 
this  peculiar  action  is  tourmaline.  The 
tourmaline  has  been  cited  in  history,  and 
is  mentioned  by  Theophrastus  and  Pliny 
under  the  name  of  Lapis .  Lyncurius .  The 
tourmaline  possesses  the  power  of  polariz- 
ing light,  and  is  usually  found  in  slightly 
irregular  three-sided  prisms  which,  when 
perfect,  are  pointed  at  both  ends.  It  is  in- 
teresting to  note  that  in  heating  such  a 
crystal  as  the  tourmaline,  it  attracts  light 
pith  balls  to  its  ends  when  electrified.  If 
the  temperature  is  kept  steady,  then  no 
such  electrical  effects  are  observed  either 
at  high  or  low  temperatures,  and  again 
the  phenomenon  ceases  altogether  if  the 
crystal  is  warmed  above  150°  C.  If  a 
heated  crystal  of  tourmaline  is  suspended 
by  a  silk  fiber,  it  will  be  attracted  and  re- 
pelled by  electrified  bodies  or  by  a  second 
heated  tourmaline.  Among  other  crystals 
which  belong  in  the  pyro-electric  family 
are  silicate  of  zinc,  boracite,  cane  sugar, 
quartz,  tartrate  of  potash  and  sulfate  of 
quinine. 

Electricity  is  produced  by  the  disruption 
and  cleavage  of  certain  substances,  as  for 
instance,  when  a  sheet  of  mica  is  split 
apart,  which  action  is  usually  accompanied 
by  the  production  of  a  number  of  sparks, 
and  both  laminae  are  found  to  be  elec- 
trified. If  sulfur  is  fused  in  a  glass  dish 
and  allowed  to  cool,  it  becomes  powerfully 
electrified,  which  action  may  be  tested  by 
lifting  out  the  crystalline  mass  with  a 
glass  rod.  Chocolate  is  another  substance 
which  manifests  such  an  electrification 
while  becoming  solidified. 

Piezo-Elcctricity  is  the  term  given  to 
that  form  of  electrical  energy  produced 
when  certain  crystals  are  placed  under  pres- 
sure in  a  certain  direction.  With  respect 
to  the  make-up  of  the  crystal,  it  was  found 
that  if  a  crystal  of  calspar  was  prest  be- 
tween the  fingers  so  as  to  compress  it  along 
the  blunt  edges  of  the  crystal,  that  it  be- 
comes electrified,  and  retains  its  electrical 
charge  for  some  days.  This  phenomenon 
is  believed  to  be  due  in  certain  crystals  to 
what  is  known  technically  as  skew-sym- 
metry or  hemihedry  in  their  molecular 
structure. 

Thermo-electricity:  If  we  take  two 
metal  bars,  one  of  bismuth  and  one  of 
antimony,  and  join  these  together,  it  will 
be  found  that  an  electric  current  is  pro- 
duced of  an  appreciable  magnitude  when 
the  juncture  between  the  metals  is  heated 
in  the  flame  of  a  candle  or  other  source 
of  heat.  To  demonstrate  that  there  is  an 
electric  current  produced  in  all  such  cases, 
it  is  but  necessary  to  connect  a  sensitive 
electric  current-detecting  device,  such  as  a 
galvanometer  to  the  free  ends  of  the  bis- 
muth-antimony couple,  as  it  is  called.  If 
all  parts  of  the  circuit,  including  all  sec- 
tions of  the  bismuth-antimony  couple,  are 
at  one  temperature,  there  will  be  no  cur- 
rent produced,  since  the  electro-motive 
forces  are  in  perfect  equilibrium.  How- 
ever, when  a  junction  between  two  such 
metals  is  heated,  this  equilibrium  of  the 
electrons  and  molecules  no  longer  exists, 
and  gives  way  to  the  production  of  an 
E.M.F.  or  difference  of  potential. 

(Continued  on  page  71) 


May,  1917 


THE  ELECTRICAL  EXPERIMENTER 


13 


SOURCES  OF  ELECTRICITY 


{For  description  see  opposite  page.) 


14 


THE  ELECTRICAL  EXPERIMENTER 


May,  1917 


Magnetism  Produces  Remarkable  Photographs 


WHAT  causes  iron,  a  dense, 
heavy  substance,  to  ignore  or 
overcome  the  laws  of  gravity 
and  to  dart  thru  space  to  a 
magnet?  What  is  this  mys- 
sterious,  so  called,  attraction?  Can  this 
swift  and  sure  motion  of  a  heavy  body 
thru  space  be  caused  by  lines  of  force  with- 
out motion,  by  lines  of  tension  in  ether  or 


BY  F.  F.  MACE 
Superintendent  of  Public  Schools,  Pecos,  Texas 

sistent  with  the  laws  of  nature,  for  all  the 
facts  of  magnetism.  Jk 

But  even  this  was  not  sufficient.  The 
facts  of  nature  had  been  distorted  for 
years.  These  experiments,  conclusive  as 
they  were,  might  be  distorted  and  thrown 
aside.  It  must  be  proven  beyond  a  shadow 
of  doubt  in  some  striking  manner  that 
there  are  actually  currents  about  the  mag- 


of  vibration,  be  such  as  to  effect  the  pho- 
tographic plate?  I  could  only  try  it,  as 
I  had  tried  other  things,  and  hope  to  obtain 
the  result  sought. 

The  result  justified  the  hope.  Taking 
every  precaution  known  to  a  photographer 
to  prevent  the  result  being  effected  by  light 
or  other  influences  I  exposed  a  plate  on 
which  were  placed  a  number  of  objects 


Fig.  2.    Photograph  Taken  in  Usual  Manner, 
Showing    the    Various    Objects  "Magneto- 
graphed." 

by  mere  lines  of  direction,  like  lines  of  lati- 
tude or  longitude?  Can  these  lines  of 
force  tending  or  extending,  moving  with- 
out motion  from  one  pole  to  the  other, 
or  lines  of  force  or  .tension  "emerg- 
ing," without  motion,  from  one  pole  and 
"entering,"  without  motion,  the  other  pole, 
produce  the  same  result  at  both  poles? 
Can  any  possible  arrangement  of  the 
molecules  of  the  magnet,  supposing  this 
arrangement  to  be  brought  about,  possibly 
extend  thru  space  and  accomplish  this 
result?  Can  any  or  all  of  these  mir- 
acles, these  things  themselves  contradic- 
tions of  the  known  laws  of  nature,  bring 
about  another  miracle — a  result  oppos- 
ing, apparently,  one  of  the  laws  of  na- 
ture? Is  there  a  cause  for  these  things 
in  keeping  with  the  known  laws  of  na- 
ture? 

These  questions  presented  themselves 
when  I  first  studied  physics.  They 
asked  themselves  more  insistently  when 
I  began  to  teach  physics,  and  they  have 
been  reiterated  again  and  again  in  vary- 
ing form  by  every  class  of  beginners 
whom  I  have  appeared  before.  For 
more  than  fifteen  years  I  sought  to  ob- 
tain an  answer,  a  true  answer,  to  these 
questions — an  answer  which  would  really 
account  for  the  facts  and  which  would 
be  in  accord  with  the  other  known  laws 
of  nature.  For  years  only  a  faint  glim- 
mering of  the  truth  appeared.  Then 
gradually  the  light  grew  stronger  until  I 
had  worked  out  a  clear  and  logical  an- 
swer. But  to  answer  these  questions  by 
pure  logic  based  on  the  known  facts  of 
nature  was  not  sufficient.  Modern 
science  demands  experiment;  tho  New- 
ton and  Galileo,  and  Leplace  never  per- 
formed an  experiment  but  based  their 
discoveries  on  the  facts  before  them. 
Therefore,  I  worked  patiently  for  years 
to  demonstrate  in  a  new  way  that  which 
I  knew  to  be  true,  until  I  had  proven  by 
experiment,  that  which  I  had  proven  by 
logical  deduction,  that  the  attraction  of 
the  magnet  and  all  of  the  phenomena  of 
magnetism  are  produced  by  the  motion 
of  ether  currents  about  and  thru  the 
magnet,  and  until  I  was  able  to  demon- 
strate the  cause,  nature,  and  direction 
these  currents,  and  by  the  direction 
these  currents  to  account  logically,  con- 


Fig.  3.     Here  We  See  the  Best  "Magneto- 
graph"  of  the  Objects  in  Fig.  2;  It  Was  Made 
In  a  Vacuum. 

net — that  there  is  motion.  How  could  this 
be  done?  I  had  worked  with  photography 
for  years  and  was  familiar  with  the  X-ray. 
While  pondering  this  situation  the  thought 
occurred  to  me :  will  the  photographic 
plate — a  photographic  plate  in  a  vacuum — 
prove  this?  A  photographic  plate  is  only 
affected  by  motion ;  by  light,  which  is  ether 
motion;  by  chemical  action,  which  is  mole- 
cular motion ;  by  heat,  which  is  molecular 
motion ;  and  by  the  X-ray,  which   is  in 


of 

of 


ig.  1.    How  the  Author  Arranged  the  Objects  to 
e  Photographed  by  a  Magnet,  Placing  Them  on 
Photo  Plate  Under  the  Bell  of  a  Vacuum  Pump, 
Permitting  the  Air  to  Be  Exhausted. 

motion.  Even  granting  the  ether  currents 
about  the  magnet  as  I  had  proven  them  to 
exist,  would  their  wave  length,  their  rate 


Fig.  4.  Exposure  of  Photo  Plate  and  Vari- 
ous Objects  Placed  Over  a  Magnet  Under 
Atmospheric  Pressure.    Compare  with  Fig.  3. 

under  an  exhausted  receiver.  At  the  end 
of  three  days  I  removed  and  developed  the 
plate.  Images  were  there,  faint  but  un- 
mistakable. The  experiment  was  a  success  ! 
I  am  sorry  that  I  afterwards  dropt  and 
broke  this  first  plate  while  attempting  to 
handle  it  during  a  spell  of  illness. 

With  certain  success  before  me  I  took 
every  precaution  to  render  the  result  be- 
yond question.  In  a  dark  room  from  which 
every  ray  of  light  was  excluded,  using  only 
_  a  perfectly  safe  ruby  light,  I  placed  ob- 
jects on  a  common  photographic  plate 
and  placed  them  under  the  receiver  of 
an  air  pump  as  shown  in  Fig.  1.  These 
articles  are  shown  in  Fig.  2,  as  they 
appear  when  photographed  with  an  or- 
dinary camera.  "A"  is  a  lead  ring  or 
washer.  "B"  and  "C"  are  metric 
weights.  "D"  is  a  piece  of  gasket  rub- 
ber. "E"  is  a  broken  metal  buckle. 
"F"  is  a  bone  button.  "G"  is  a  scrap 
of  acid-eaten  zinc.  "H"  is  a  wooden 
button.  "J"  is  a  piece  of  sealing  wax. 
"K"  is  a  lump  of  resin.  The  magnet 
used  'is  an  ordinary  steel  U-magnet, 
weighing  one  kilogram  (or  2.2  lbs.). 
The  •  msitive  side  of  the  plate  is  above 
and  the  objects  lie  on  the  sensitive  side. 

After  the  objects  were  placed  on  the 
plate  under  the  receiver,  twelve  thick- 
nesses of  black  cloth  were  placed  over 
the  receiver  and  the  air  was  exhausted. 
Then  over  all  of  this  was  placed  a  light- 
tight  box  and  the  .whole  was  finally 
wrapt  in  ten  thicknesses  of  black  cloth. 
The  ruby  light  was  then  removed  from 
the  room  and  the  room  was  locked  and 
not  reopened  for  twenty  days.  I  may 
add  that  the  whole  operation  took  place 
after  nightfall. 

At  the  end  of  twenty  days  the  room 
was  entered  after  dark  and  the  plate 
was  taken  from  the  receiver  and  de- 
veloped by  ruby  light  as  with  an  ordin- 
ary photograph.  The  result  is  shown  in 
Fig.  3.  The  articles  are  lettered  to 
correspond  to  Fig.  2.  The  one  marked 
"D"  was  lost  and  is  not  included  in 
Fig.  2. 

Here  is  incontestable  proof  that  there 
is  motion,  that  there  are  currents,  about  a 
magnet.    No  mere  line  of  force,  no  ten- 
sion in  ether,  no  mere  line  of  direction 
(Continued  on  page  70) 


May,  1917 


THE  ELECTRICAL  EXPERIMENTER 


The  Therapy  of  Light  and  the  New  "R-Ray" 

By  H.  ROSENTHAL 


THE  therapeutic  use  of  light  has 
been  known  for  ages ;  in  fact,  it 
belongs  to  a  period  so  remote 
that  we  are  unable  to  determine 
even  approximately  the  time  of 
its  introduction  as  a  healing  agent. 

In  the  far  East  the  earliest  writings  men- 
tion the  use  of  light  in  the  cure  of  disease, 
and  in  the  comparatively  more  recent  rec- 
ords of  Central   American  aborigines  we 


Fig.  1.  Appearance  of  Special  Electric  Arc 
Devised  for  Producing  the  "R-Ray"  Radia- 
tions, Which  Have  Proven  Extremely  Satis- 
factory in  Light  Therapy  Treatment  for 
Certain    Diseases   and  Ailments. 

find  accounts  of  miraculous  cures  per- 
formed by  the  Sun  God.  Even  at  the  time 
of  our  early  pioneers  on  this  continent 
there  are  authentic  reports  of  a  custom 
practised  by  many  Indian  tribes,  who  treat- 
ed wounds  and  pulmonary  afflictions,  rheu- 
matism, neuralgia,  et  cetera,  by  exposing 
the  naked  skin  to  the  mid-day  sun,  allowing 
the  rays  to  fall  directly  on  the  part  af- 
flicted. This  custom  was  in  vogue  ages 
before  the  Spanish  Conquest,  and  was  com- 
mon among  the  aborigines  of  America, 
from  Yucatan  to  the  Arctic  Sea. 

We  have,  therefore,  historic  proof  that 
light  rays  have  been  used  from  time  imme- 
morial in  the  treatment  of  disease,  and 
while  modern  science  and  modern  meth- 
ods have  attained  the  same  ends,  they  have 
not  changed  the  principles  known  to  primi- 
tive man — but  have  merely  developed  the 
art. 

As  light  rays  are  the  oldest  and  most 
universally    accepted  0 
therapeutic  agent,  we     0  _ 
naturally    ask  —  how 
are    they  translated 
into  terms  of  therapy 
by  the  human  body? 
To  which  the  answer 
is,  thru  the  medium 
of  vibration  and  pene- 
trative force  of  quan- 
tity. 

Light  and  electrical 
radiations    are  both 
waves  that  are  pro- 
jected thru  space  at 
the     same  velocity. 
They  are  identical  in  nature,  tho  one 
wave  length  or  radiation  may  differ 
from  another,  the  same  as  one  sound 
wave  may  vary  in  length  from  an- 
other, as  found  in  the  various  tones 
or  vibrations  of  music.    Yet  all  wave 
lengths,  whether  light  or  sound,  pro- 
duce  their  own  corresponding  vibrations 
and  we  therefore  recognize  all  such  vibra- 
tions in  terms  of  light  or  sound. 

Tn  further  proof  of  this  existing  vi- 
bratory theory  we  have  color,  which  in 
reality  exists  only  in  the  mind,  for  color 


value  is  dependent  solely  upon  the  number 
of  vibrations  impinging  upon  the  retina 
of  the  human  eye.  As  for  instance  when 
the  retina  is  stimulated  by  a  vibratory 
force  that  approximates  400  trillions  per 
second,  the  impression  produced  upon  the 
brain  is  that  of  the  color  red;  750  trillion 
vibrations  per  second  is  interpreted  by  the 
brain  as  the  color  violet.  And  so  on  thru 
the  scale  of  our  visible  spectrum.  Yet, 
were  the  human  retina  sufficiently  sensitive 
to  receive  and  distinguish  the 
many  intermediate  vibrations, 
it  would  perceive,  thru  the 
brain  countless  millions  of  tints 
and  numerous  values  that  lie 
between  these  two  extremes. 

When  these  countless  mill- 
ions of  tints  are  all  combined 
we  see  only  white.  And  tho 
we  perceive  and  interpret  white 
light  as  being  white,  still  we 
know  that  it  is  not  white,  but 
the  combined  primary  colors 
and  their  countless  intermedi- 
ate tints.  This  fact  is  easily 
proved  by  simply  passing  a 
beam  of  white  light  thru  a 
prism,  which  will  show  the 
primary  colors  making  up  the 
white  beam. 

Light  vibration  without  penetration,  force 
or  quantity  is  in  itself  therapeutically  neg- 
ligible. To  have  force,  it  should  be  direct, 
and  to  have  penetration  the  source  and 
quantity  should  furnish  vibrations  of  prac- 
tically uninterrupted  intensity. 

One  source  of  light  which  fulfills  the 
above  conditions  is  our  own  sunlight,  which 
penetrates  every  portion  of  the  human  body 
and  exerts  a  most  powerful  influence  on 
its  economy  by  oxygenating  the  blood,  gen- 
erating hemoglobin  and  producing  red  cor- 
puscles. And  when  we  Lecome  Sun- 
Dodgers  we  cannot  expect  any  other  phy- 
sical condition  than  that  which  takes  place 
in  plants  under  like  circumstances,  and 
which  entails  on  human  beings  the  neces- 
sity of  resorting  to  other  means  for  making 
up  the  deficiency — generally  drugs. 

Summing  up  therefore  the  laws  that  gov- 
ern the  therapy  of  light,  we  find  it  has  the 
same  relation  to  chemical  actions  which 
are  governed  by  the  chemic  response  set  up 
in  the  substance  or  tissue,  and  not  by  the 
inherent  quality  of  the  ray;  while  all  phy- 
sical conditions  are  secured  in  direct  ratio 
to  the  penetrative  power,  quantity  and  vi- 


in  a  given  interval.  So  that  from  a  ther- 
apeutic standpoint  it  is  always  highly  im- 
portant to  have  at  our  command  as  great 
a  number  of  these  vibrations  as  possible; 
i.e.,  of  the  oscillatons.  It  has  been  averred 
by  the  medical  profession  that  each  and 
every  corpuscle  and  cellular  structure  in 
the  human  body  is  composed  of  an  infinite 
number  of  delicate  receivers,  each  of  which 
respond  only  when  the  right  tune  or  vibra- 
tion strikes  them.    Thus  when  given  ma- 


S3 

"0  I 


^-    K   <0   <n    <t  M 


tUCTWC 

OSCILLATIONS 

FROM 


STORM 
IN  SUN 


-13 


ELECTRIC 
OSCILLATIONS  - 


IN  SMALL  SPHERES 


UK  MAPT 


Fig.  2.     Chart  Showing  the  Position  Occupied  by  the  New  "R-Ray"  in  the  Soectrum, 
Including  the  Relative  Position  of  the  X-Ray  Vibrations  and  Ultra-Violet  Rays. 

4, 503, 599,627. 370,496  =  Ultra  violet  photog.  in  vacuo 

789.000,000,000.000  =  Violet  end  of  visible  spectrum 

.562,949,953.421,312  =  Green  light 

451,000,000,000,000  =  Red  end  of  spectrum 

281,474,976,710.656  =  Infra-red 

70,368.744,177,664  =  Heat  rays  of  solar  spectrum 

47,000,000,000   =  Electric  oscillations  in  small  spheres 

Oncein  4.7  seconds  =  Eiectiicoscillationstrom  storm  in  sun 

brating  quality  of  the  light  employed. 

All  light  waves  possess  two  main  charac- 
teristics that  differentiate  the  effect  pro- 
duced namely:  first,  the  number  of  vibra- 
tions in  a  given  interval  of  time,  and  sec- 
ond, the  length  of  each  oscillation  or  wave 


Fig.  3.  Spectrogram  of  the  New  "R-Ray,"  Showing  Clearly 
Its  Great  Range  in  the  Field  of  Light  Therapy,  Extending 
as  It  Does  Beyond  the  Visible  Spectrum. 

jor,  minor  and  chromatic  scales  to  operate 
with,  the  skilled  therapist  can  compel  the 
brations  of  any  cellular  structure  to  re- 
spond to  those  which  are  produced  arti- 
ficially ;  and  call  into  action  complete  ther- 
apeutic results,  just  as  in  music  we  call  in- 
to play  the  various  graduations  of  tone  and 
produce  perfect  harmony. 

The  period  of  vibration  or  oscillations 
which  make  up  light  waves  and  which  the 
human  eye  will  respond  to,  are  those  above 
the  infra-red  rays  or  heat  rays  and  those 
below  the  ultra-violet  or  invisible  light  rays. 
The  difference  between  the  two  is  that  the 
vibration  of  the  infra-red  is  very  small  and 
the  wave  length  very  long,  while  those  of 
the  ultra-violet  region  have  a  tremendous 
period  of  vibration  and  a  very  short  wave 
length. 

The  therapeutical  work  that  has  been 
conducted  points  to  the  fact  that  the  ultra- 
violet rays  are  most  advantageous  and  con- 
sequently of  greatest  use  in  light  therapy. 

We  know  that  light  rays  from  such 
sources  as  the  Finsen,  Minin.  Ultra-violet 
and  X-ray  are  each  capable  of  exciting  a 
normal,  subnormal  or  abnormal  human  re- 
ceiver. 

However,  our  sci- 
entists not  being  sat- 
isfied with  the  belief 
of  the  existence  of 
another  source  of  vi- 
bration beyond  the 
ultra-violet  region, 
took  another  step  in 
this  direction  which 
proved  to  be  success- 
ful, inasmuch  as  they 
have  found  a  region 
between  the  extrem- 
ity of  the  ultra-violet 
and  the  beginning  of 
the  X-rays.  The  re- 
gion is  still  unexplored,  but  there  is 
little  doubt  that  the  greatest  thera- 
peutic secrets  lie  hidden  there. 

It  is  believed  that  we  are  only  be- 
ginning to  learn  of  the  real  benefits 
to  be  gained  by  the  scientific  applica- 
tion of  light  rays  by  skilled  therapists. 
The  author,  who  has  been  engaged  in 
this,  as  well  as  the  electrical  field  of  re- 
search for  many  years,  discovered  a  new 
ray    which    he    has    christened    the  R- 
ray.    The  production  of  this  new  source  of 
(Continued  on  page  47) 


W<fVE 
T  N' 


LE  icvns 

METEI1S 


dCTAVEi 


1 6 


THE  ELECTRICAL  EXPERIMENTER 


May,  1917 


Powerful  Electro =Magnets  Perform  the  Work  of  Many  Men 


The  ordinary  work  of  a  man  loading 
pig  iron  from  the  ground  upon  a  railway 
car  was  from  12  to  13  tons  per  day.  The 


The  Crucible  Steel  Company  Have  in  Use  at  Their 
Pittsburgh  Plant  This  Gigantic  62-inch  Electro- 
magnet. It  Can  Lift  4'/2  Tons  of  Steel  Bars  and  the 
Trip  of  a  Switch  Releases  the  Entire  Load  Instant- 
ly. This  Class  of  Work  Spells  "Economy"  in  Big 
Letters  and  Foundries  Everywhere  Are  Rapidly 
Awakening  to  the  Fact. 


lifting  magnet,  however,  nas  rendered  it 
unnecessary  for  this  laborious  work  to  be 
performed  by  human  effort,  and  the  re- 
sults, as  given  in  the  unloading  of  the 
steamer,  Erwin  L.  Fisher,  at  Indiana  Har- 
bor, Ind.,  are  given  in  brief  below : 

With  a  cargo  of  4,000,000  pounds  of  pig 
iron,  the  time  required  to  unload  this  ves- 
sel with  twenty-eight  men  was  two  days 
and  two  nights,  which  corresponds  to  about 
3,000  pounds  per  man  per  hour,  or  about  15 
tons  per  day  of  ten  hours.  When  the 
lifting  magnet  was  introduced,  the  total 
time  required  for  unloading  was  reduced 
to  eleven  hours  and  was  done  by  two  men, 
whose  labor  consisted  in  manipulating  the 
controllers  in  the  cages  of  the  cranes.  Thus 
two  men  and  two  magnets  duplicated  the 
work  of  twenty-eight  men  in  less  than  one- 
fourth  the  time.  Under  these  conditions 
the  handling  capacity  of  a  man  and  a  mag- 
net was  nearly  one  thousand  tons  in  eleven 
hours,  or  about  900  tons  per  day  of  10 
hours.  This  is  fifty  times  as  much  as  was 
accomplished  by  hand  labor,  or  twenty 
times  as  much  as  is  possible  even  under 
scientifically  managed  manual  labor.  Fur- 
thermore, the  operation  was  chargeable 
with  less  than  one-fourth  the  overhead 
charges,  while  the  vessels  were  enabled  to 
double  their  number  of  productive  trips. 

The  lifting  magnet  has  been  adapted  for 
the  handling  of  materials  in  all  branches 
of  the  iron  and  steel  industry.  It  is  used 
for  handling  pig  iron,  scrap,  castings,  bil- 
lets, tubes,  rails,  plates,  crop  ends ;  for  load- 
ing and  unloading  cars  and  vessels,  and  for 
handling  skull-cracker  balls  and  miscella- 
neous magnetic  material.  In  fact  it  seems 
to  be  axiomatic  that  wherever  magnetic 
material,  and  especially  raw  material,  is  to 
be  handled  in  any  considerable  quantity,  a 
lifting  magnet  can  be  used  to  advantage 
and  will  be  a  profitable  investment. 

The  accompanying  illustration  shows  in 


a  marked  manner  the  practical  application 
and  efficiency  of  iarge  electro-magnets  used 
industrially.  The  first  illustration  shows  a 
gigantic  electro-magnet  measuring 
62  inches  in  diameter  and  swung 
from  a  crane  at  'the  plant  of  the 
Crucible  Steel  Company  at  Pitts- 
burgh. This  mighty  magnet  has 
been  photographed  in  the  act  of  lift- 
ing 17  steel  billets,  each  weighing 
575  lbs.,  or  a  total  of  8,925.  It  takes 
but  a  moment's  reflection  to  readily 
conceive  just  how  much  man-power 
would  be  required  to  move  this 
same  weight  of  steel,  not  to  men- 
tion the  time  occupied  in  moving  it. 
A  single  operator,  in  this  case  the 
man  operating  the  crane,  lowers  the 
magnet  onto  the  steel  bars  and  when 
in  contact  or  nearly  so,  he  closes  the 
switch  supplying  the  magnet  with 
electric  current.  The  magnet  in- 
stantly becomes  alive  and  exerts 
several  tons  of  magnetic  tractive 
power  and  holds  the  billets  to  its 
face  securely,  as  pictured  in  the  il- 
lustration. The  crane  may  swing 
along  for  several  hundred  feet,  car- 
rying its  suspended  load,  and  as 
soon  as  it  reaches  the  desired  loca- 
tion the  magnet  is  lowered;  when 
the  operator  opens  the  switch  the 
magnet  instantly  releases  its  tons 
of  steel. 

The  second  illustration  shows  a 
powerful  electro-magnet  at  work  in 
the  yards  of  the  Chicago,  Milwau- 
kee and  St.  Paul  Railroad's  West 
Milwaukee  shop,  the  magnet  meas- 
uring 43  inches  in  diameter  and  lift- 
ing in  this  case  a  locomotive  drive 
wheel.  The  lifting  magnet  is  an  at- 
tractive proposition  to-day  and  not 
only  appeals  in  large  sizes  but  in  the  very 
small  sizes  as  well.  The  small  hand  type 
electro-magnet  is  particularly  efficacious  .for 
picking  up  quantities  of  iron  nails,  screws, 
etc.,  in  hardware  stores  and  stock  rooms 
and  finds  application  in  a  thousand  and  one 
different  ways  daily. 


THE  ELECTRIC  HEATER  FOR  THE 
KITCHEN  BOILER. 

The  accompanying  semi-sectional  view 
of  an  ordinary  kitchen  boiler  shows  how 
a  recently  perfected  electric  water  heater 
is  attached  to  it.  This  heater  heats  the 
water  before  you  turn  the  faucet  and  not 
■ — some  time  afterward.  The  tank  is  always 
charged  with  scalding  water  at  any  tem- 
perature you  wish 
up  to  2  00°  F. 
(212  0  F.  boiling 
point),  or  enough 
heat  for  about 
five  baths — always 
on  tap. 

The  heater  has 
six  steps — and  the 
regulator  is  a  six- 
point  current  con- 
trol. When  no 
water  is  being 
drawn  the  heater 
will  probably  be 
cut  entirely  out  so 
that  no  electricity 
is  being  used. 
Then  as  some 
water  is  drawn 
the.  regulator  picks 
out  that  step  of 
the  heater  which 
will  pump  back 
into  the  boiler  the 
same  amount  of 
heat  that  is  drawn 
from  the  faucet 
in  the  hot  water. 
At  the  sixth  step 
the  regulator  ap- 
plies two  full 
horsepower,  stor- 
ing heat  at  100% 
efficiency.  It  is  claimed  that  this  partic- 
ular electric  water  heater  will  operate  on 
15  to  20  per  cent  less  energy  than  the  cir- 
culation type  heater,  for  the  same  monthly 
gallon  production. 

The  present  heater  has  been  specially  de- 
signed to  make  it  self-cleaning.  Under 
tne  intermittent  operation  of  the  thermal 
control  there  appears  a  slight  but  constant 
opening  and  closing  of  the  split  heating 
tube,  which  readily  cracks  off  all  scale  and 
any  precipitate  forming  on  the  tube.  This 
deposit  accumulating  at  the  base  of  the 
heater  is  then  easily  flushed  out  of  the  full 
size  1 '4-inch  drain.  This  self-cleaning 
feature  is,  perhaps,  next  to  efficiency  in  im- 
portance to  the  housewife  to  whom  a 
burned-out  heater  means  not  only  needless 
expense  but  several  days'  interruption  in 
the  hot  water  service  and  a  recent  engineer- 
ing report  gives  the  external  circulation 
type  water  heater  four  months  in  which  to 
become  absolutely  choked  with  scale. 


An    Electric  Heating 
Unit    That     Fits  the 
Kitchen  Boiler. 


43-inch  Magnet  Lifting  a  Lecomotive  Drive 
Wheel  at  the  West  Milwaukee  Shop  of  the 
C.  M.  &  St.  Paul  Railway.  Another  Instance 
of  What  the  Lifting  Magnet  Is  Capable  of 
Doing. 


CAN  SINK  SUBMARINES  BY 
WIRELESS,  SAYS  INVENTOR. 

Theodore  Eichholz,.  a  young  engineer 
and  architect  of  Pittsburgh,  has  invented  a 
wireless  device  that  may  be  used  to  destroy 
submarines  by  causing  an  explosion  of 
gases  that  are  always  present  in  submer- 
sibles,  he  claims.  For  several  years  the  in- 
ventor was  connected  with  the  United 
States  Corps  of  Engineers. 

Mr.  Eichholz  stated  that  just  recently 
a  small  experimental  apparatus  in  his  home 
on  Neville  Island  sunk  a  small  "dummy" 
submarine  in  the  Ohio  River,  five  miles 
away.  The  destroyed  model  was  of  steel 
and  submerged  to  a  depth  of  ten  feet. 

All  submarines  while  under  water  are 
propelled  by  electric  storage  batteries 
which  throw  off  a  gas  that  pervades  the 
hull.  This  gas,  Eichholz  says,  he  detonates 
by  the  wireless  current  and  destruction 
follows.  The  apparatus  will  be  submitted 
to  the  U.S.  Government  at  once. 


May,  1917 


THE  ELECTRICAL  EXPERIMENTER 


17 


NOVEL  TELEGRAPH  INSTRU- 
MENT THAT  RESPONDS  TO 
VOICE. 

Strange  as  the  title  may  seem,  yet  the 
successful  operation  of  such  a  device  has 
been  accomplished  thru  the  researches  of 
Mr.  Christian  Berger  of  New  York  City. 

The  accompanying  photograph  shows  the 
complete  equipment  of  the  electric  voice- 
operated  telegraph  instrument.  The  opera- 
tion of  the  device  is  not  attained  by  the 
employment  of  a  microphone  of  any  kind, 
but  by  means  of  a  sensitive  sound-oper- 
ated circuit-breaker,  which  controls  a  spe- 
cial relay  and  which  in  turn  operates  elec- 
trically either  a  sounder  or  recording  in- 
strument. The  circuit-breaker  is  placed  in 
a  metal  box  which  is  seen  in  the  center 
background  of  the  photograph.  This  con- 
sists of  a  bent  wire,  properly  balanced  on 
an  insulating  block.  The  end  of  this  wire 
presses  lightly  against  the  side  of  the  box-, 
which  makes  a  permanent  contact  when  it 
is  not  disturbed.  The  second  connection 
is  made  thru  the  metal  box  and  this  is  ter- 
minated with  one  binding  post  of  a  bat- 
tery, while  the  bent  wire  is  connected  to  one 
side  of  the  relay  electro-magnet,  the  op- 
posite side  being  linked  to  the  other  bind- 
ing post  of  the  battery.  The  electro-mag- 
net actuates  an  armature  which  controls 
a  cog-wheel  by  means  of  a  projecting  strip 
on  the  armature.  On  the  same  shaft  with 
the  cog-wheel  is  a  drum  upon  which  a 
number  of  contacts  are  secured.  These  are 
alternately  connected,  so  that  one  will  com- 
plete the  electrical  circuit  when  desired 
and  when  moved  to  the  next  stud,  the  cir- 
cuit will  be  opened.  It  is  built  on  the  lines 
of  a  step-by-step  relay,  which  has  been 
used  some  years  ago  for  controlling  mov- 
ing vessels  by  radio  waves.  The  drum  cir- 
cuit and  the  horizontal  brushes  which  touch 
the  drum  studs,  are  connected  in  series 
with  the  recording  instrument  and  battery. 

The  operation  of  the  apparatus  is  ex- 
ceedingly simple  as  one  must  only  be  fa- 
miliar with  the  telegraph  code,  but  not 
experienced  in  handling  a  telegraph  key, 
as  the  transmitting  is  done  by  calling  out 
the  dot  and  dashes  to  the  instrument. 
When  a  signal  is  made  the  sensitive  sound 
actuated  circuit-breaker  opens  the  circuit 
which  causes  the  armature  of  the  relay  to 
release  it,  thus  giving  a  rotary  motion  to 
the  cogwheel  and  in  turn  closing  the  re- 
cording instrument  circuit.  The  complete 
equipment  is  very  interesting  when  in  ac- 
tion and  possesses  many  diversified  possi- 
bilities. 


LOS  ANGELES  HAS  WONDERFUL 
ELECTRIC  FIRE  TRUCK. 

THE  electric  equipment  of  a  new 
fire-fighting  apparatus  recently 
built  by  the  Los  Angeles  fire  de- 
partment has  no  equal  in  the 
country.  This  equipment  is 
mounted  on  a  ton  and  a  half  motor  truck 


As  a  precaution  against  any  one  accident- 
ally touching  the  foot  throttle  and  speeding 
up  the  engine  to  too  great  a  speed,  when 
the  wagon  is  standing  at  a  fire,  a  special 
protective  device  has  been  provided,  which 
consists  of  a  hood  which  can  be  lowered 
and  locked  in  a  position,  completely  pro- 
tecting the  foot  throttle  from  the  curious. 


Los  Angeles,  Cal.,  Boasts  of  Having  One  of  the  Most  Complete  Electric  Fire-fighting  Trucks 
in  the  United  States.  The  Equipment  Comprises  Five  Powerful  Searchlights  Which  Are 
Supplied  with  Power  from  Either  a  Large  Storage  Battery  or  the  Dynamo  Shown  in  the 

Picture. 


Speak  to  This  Telegraphic  Novelty  and  It  Recor 
alent  Dots  and  Dashes  on  a  Paper  T 


ICELAND'S  ELECTRICAL  PAPER. 

Elcktron  is  the  name  of  an  electrical 
magazine  publisht  monthly  at  Reykjavik, 
Iceland.  The  leading  article  is  on  the  Ice- 
landic telegraphs  and  telephones,  by  Mr. 
Gisli  J.  Olafsen,  who  visited  this  country 
a  year  or  more  ago  and  studied  American 
telegraph  and  telephone  methods.  This  ar- 
ticle is  printed  in  the  Danish  and  English 
languages. 


and  was  both  designed  and  built  by  mem- 
bers of  the  fire  department. 

The  equipment  consists  of  five  powerful 
searchlights,  each  rated  at  250  watts,  capa- 
ble of  throwing  a  brilliant  beam  of  liglit 
over  500  feet  away.  At  this  distance  work 
at  a  fire  can  be  carried  on  with  great  effi- 
ciency. Yet  these  lights  are  so  arranged 
with  diffusing  lenses  that  it  does  not  blind 
the  firemen,  even  a  few  feet  away. 

The  lights  are  16  inches   in  diameter. 

Three  are  permanent  and 
two  are  portable,  each  be- 
ing attached  to  320  feet  of 
heavily  insulated  cable 
wound  on  a  reel  which  can 
be  unrolled,  permitting  the 
lights  to  be  carried  this 
distance  into  a  burning 
building. 

The  handicap  of  a  strange 
and  smoky  building  is  over- 
come by  the  use  of  these 
portable  lights.  They  will 
penetrate  smoke  to  almost 
an  unbelievable  distance, 
permitting  the  firemen  to 
fight  fires  thru  dense  smoke 
with  the  greatest  of  ease. 
Power  is  received  from  eight  large  stor- 
age batteries  placed  behind  the  seat.  These 
batteries  themselves  are  capable  of  furnish- 
ing current  for  the  lights  for  seven  hours. 
Also  installed  on  the  right  foot-board  is 
a  generator  of  50  amperes,  25  volts,  1.25 
K.W.  This  is  run  by  a  silent  chain  drive 
off  the  main  propeller  shaft  and  is  con- 
trolled by  a  separate  clutch,  shown  in  front 
of  the  switchboard  seen  in  the  photo.  The 
generator  may  be  cut  in  or  out  at  will,  by 
means  of  this  clutch. 


ds  the  Equiv- 
ape. 


A  perfectly  equipt  switchboard  is  mount- 
ed on  the  right  side  immediately  above  the 
generator,  having  a  marble  back  in  an  en- 
closed case  with  a  glass  front.  It  is  equipt 
with  a  master  switch  for  both  the  bat- 
teries and  generators.  Also  an  individual 
switch  for  each  light  and  gages  to  show 
amperes  and  volts,  a  resistance  cut-out  and 
small  lights  to  illuminate  the  board.  Fuses 
of  proper  capacity  are  installed  for  each 
switch.  To  prevent  damage  to  generator  or 
batteries  an  under-load  and  an  over-load 
switch  is  installed.  This  acts  as  a  gover- 
nor, the  purpose  of  which  is  to  automatical- 
ly disengage  the  charging  line  from  the 
generator  when  the  rate  of  charge  reaches 
a  dangerous  value  or  when  the  rate  of 
charge  is  so  low  that  there  would  be  dan- 
ger of  the  batteries  bleeding. 

The  portable  lights  are  adapted  to  be 
used  on  a  tripod.  They  are  mounted  on 
the  wagon  on  a  swivel  connection  with  a 
one-inch  diameter  stem  projecting,  which 
fits  into  a  socket  fastened  with  a  nut. 
A  similar  socket  is  provided  on  the  tripod 
and  when  the  light  is  set  on  the  tripod,  a 
large  hand  nut  is  provided  which  holds  it 
securely.  The  light  mounted  on  the  tripod 
can  be  readily  moved  from  place  to  place 
by  one  man.  As  he  carries  the  light  to 
he  fire  the  reel  automatically  unwinds. 


A  wireless  telegraph  distance  record  of 
11,500  miles  was  establisht  by  the  steamer 
Sonoma,  which  pickt  up  messages  from  Eil- 
vese,  Germany,  when  two  days  off  Austra- 
lia, according  to  Royden  Thomberg  and 
Clio  Bowers,  operators  on  the  Sonoma. 
Ellery  Stone,  assistant  United  States  radio 
inspector  at  San  Francisco,  said  it  was 
the  greatest  distance  achievement  in  wire- 
less telegraphy. 


IS 


THE  ELECTRICAL  EXPERIMENTER 


May,  1917 


MONSTER  MOTOR  GREATEST 
EVER  BUILT. 

We  are  told  that  at  one  time  this  old 
world  of  ours  was  inhabited  by  gigantic 
monsters.  Well,  we  still  have  monsters — 
mechanical  ones — that  are  far  more  pow- 
erful  than  any   of   which   our  ancestors 


The   Egyptians   Built  the  Pyramids — but  Se 
Builds  an  Electric  Motor  Developing  the  Com 
Horses.    This  Is  the  Largest  Motor 

knew.  Take,  for  instance,  the  mastodonic 
Westinghouse  reversing  motor  here  shown, 
which  was  specially  designed  for  driving 
35-inch  reversing  blooming  mills  in  large 
steel  plants.  When  we  realize  that  it  has 
a  capacity  of  15,000  horsepower,  the  largest 
electric  motor  ever  built,  we  need  no  fur- 
ther proof — we  know  it  is 
monstrous.  Some  idea  of 
its  size  may  be  gained  when 
it  is  stated  that  the  man 
standing  alongside  the  mo- 
tor is  six  feet  tall. 


TRAVELING  ELECTRIC  SIGN  FOR 
SHOW-WINDOWS. 

The  traveling  electric  sign  here  illustra- 
ted is  a  new  moving  feature  sign  for  win- 
dow attraction  that  can  be  operated  where 
heretofore  the  ordinary  signs  have  been 
used.  It  displays  the  same  amount  of  read- 
ing that  ordinarily  requires 
a  30-ft.  length  of  space  into 
a  3l/>-fo.  space.  The  word- 
ing can  be  changed  as  often 
as  desired. 

Four  10-watt   lamps  are 
used    for    illuminating  the 
sign,  and  the  motor  which 
operates   the   moving  band 
uses   only  about  20  watts. 
Motor  and  lamps  together 
use    about    the  same 
amount  of  current  as  a 
32-c.p.    lamp.  During 
the  daytime,  when  the 
motor  only  is  working, 
it  uses  less  than  one- 
half  as  much  and  the 
sign    is    equally  effect- 
ive. 

Any  length   of  film 
from  6  ft.  to  30  ft.  can 
be  used  and  changed  in  a  few  minutes. 

This  sign  can  be  operated  on  either  100 
to  120  volts  direct  current  or  100  to  120 
volts  (60  cycle  or  less)  alternating  current 
by  changing  the  connections  at  the  termi- 
nal board. 

The  sign  comes  complete,  ready  for  use, 


e  How  Modern  Man 
bined  Power  of  15,000 
Ever  Built. 


The  Travelin 
Cabinet,  the 


ELECTRIC  LIGHTS 
CHEAPER  THAN 
KEROSENE. 

How  much  cheaper  are 
gas  mantles  and  electric 
bulbs  than  candles?  The 
Society  for  Electrical  De- 
velopment, anxious  to  en- 
courage a  wider  use  of  elec- 
tricity for  lighting,  has  pre- 
pared figures  showing  that 
both  are  much  cheaper  than 
candles  or  kerosene,  and 
that  electric  light,  while  it  is 
more  expensive  than  light 
from  a  gas  mantle,  is  much  cheaper  than 
light  from  an  open  gas  flame. 

A  recent  test  of  six  candles  showed 
that  for  one  cent  only  2.68  candle-power 
hours  were  obtained.  If  electricity  for 
lighting  costs  nine  cents  for  a  kilowatt-hour 
a  20-watt  lamp  can  be  lighted  for  50  hours 
for  nine  cents.  The  efficiency  of  a  20-watt 
incandescent  is  a  candle-power  for  1.17 
watts.  Thus  a  20-watt  lamp  will  provide 
about  17  candle-power.  It  will  burn  50 
hours  for  nine  cents  or  850  candle-power 
hours  will  cost  nine  cents.  One  cent  will 
buy  94.4  candle-power  hours,  or  35  times 
as  much  light  as  can  be  obtained  from  a 
candle  for  one  cent. 

Ordinary  kerosene  lamps  with  kerosene 
at  15  cents  will  give  72  candlepower  hours 
for  one  cent.  Figuring  electricity  at  nine 
cents  a  kilowatt  hour  as  above,  we  find  72 
candle-power  hours  for  one  cent  balanced 
against  94  for  electricity,  or  a  margin  of 
22  candle-power  hours  in  favor  of  electrici- 
ty. With  an  open  gas  flame  and  gas  cost- 
ing 85  cents  a  thousand  cubic  feet,  one  cent 
will  buy  51  candle-power  hours.  For  this 
price  electricity  will  provide  94  candle-pow- 
er hours.  Thus  balancing  gas  against  elec- 
tricity, we  find  the  margin  to  be  43  in  fa- 
vor of  electricity.  Gas  mantles  have  be- 
come very  popular  and  with  best  mantles 
one  cent  will  buy  201  candle-power  hours. 


g   Electric  Sign  Provides  30  Ft.  of  Word  Space 
Moving   Belt  Presenting  An    Ever-changing  Sign 
Adapted  to  Show  Windows. 


and  can  be  operated  from  any  convenient 
lamp  socket.  It  can  be  set  anywhere,  or 
suspended  with  cords  to  hang  at  the  top, 
middle  or  back  of  any  show  window. 

MUNICIPAL  TROLLEY  OF  SEAT- 
TLE LOSES  MONEY. 

The  municipal  street  railways  of  Seattle, 
Wash.,  continue  to  lose  money,  as  shown 
by  the  report  of  A.  L.  Valentine,  superin- 
tendent of  public  utilities,  in  his  report  for 
October,  the  net  loss  being  about  $2,000 
monthly.  Since  f.ie  city  light  dept.rtment 
took  over  the  street  railway  substations  the 
power  cost  is  being  checked  against  the 
value  of  the  substations,  so  that  in  October 
the  street  railways  received  $1,069  worth  of 
power  without  cash  outlay. 

SAYS  U.S.  SHIPS  HAVE  GREATEST 
RADIO  RANGE. 

After  he  had  inspected  radio  apparatus 
on  a  number  of  vessels  recently,  Secretary 
Redfield  of  the  Department  of  Commerce 
said  that  American  vessels  have  a  wider 
range  in  sending  and  receiving  messages 
than  ships  of  other  countries.  He  also  as- 
serted that,  from  a  comparison  which  he 
made  of  apparatus  cn  an.  American  and  a 
British  steamer,  the  wireless  regulations 
past  by  Congress  give  greater  power  to  ra- 
dio inspectors  than  do  British  regulations. 


NEW  VACUUM  BULB  RECTIFIER 
FOR  BATTERY  CHARGING. 

The  latest  novelty  in  small  rectifiers  for 
charging  storage  batteries  rated  at  2  to  6 
amperes  charging  rate  and  from  7.5  to  75 
volts  is  here  illustrated.  It  operates  on  a 
new  principle  for  this  class  of  apparatus. 
The  discovery  that  made  it  possible  is  the 
perfection  of  the  small  bulb  similar  to  that 
of  an  incandescent  lamp,  in  which  recti- 
fication of  the  current  takes  place.  This 
bulb  is  filled  with  an  inert  gas  and  contains 
a  tungsten  filament  and  a  grafite  anode.  It 
screws  into  a  lamp  socket  in  the  outfit. 

A  black-japanned  casing  with  perforated 
top  furnishes  the  mounting  and  incloses  all 
live  parts.  This  casing  carries  the  bulb,  a 
fuse  to  protect  against  reversal  and  other 
overload  and  the  compensator  which  re- 
duces the  alternating  current  without  waste- 
ful resistance  and  excites  the  tungsten  fila- 
ment. For  charging,  the  rectifiers  need 
only  be  connected  to  a  convenient  lamp 
socket  and  the  pair  of  leads  attached  to  the 
proper  posts  on  the  battery. 

The  smallest  unit  is  of  2  amp.  maximum 
capacity.  From  a  115  volt,  60  cycle  alter- 
nating current  circuit  it  will  charge  three 
lead  battery  cells  at  2  amp.,  six  cells  at 
about  1  amp.,  and  eight  cells  at  0.75  amp. 
Between  these  figures  the  charging  rate  is 
proportionate.  At  10  cents  the  kilowatt 
hour  for  current,  the  cost  is  about  1  cent 
the  hour,  including  tube  renewal  costs.  The 
weight  is  about  15  lbs.  Medium  size  recti- 
fiers have  a  capacity  of  6  amp.,  7.5  to  15 
volts,  and  are  designed  pri- 
marily for  charging  three  or 
six-cell  automobile  starting 
or  lighting  batteries  in  home 
garages.  This  type  is  de- 
signed for  115  volts,  60-cy- 
cle  current,  but  may  be  used 
on  105-  to  125-volt  circuits. 
The  weight  is  about  15  lbs. 
The  largest  type  is  designed 
for  use  in  public  garages 
and  service  stations,  and 
has  a  capacity  of  6  amp., 
7.5  to  75  volts.  It  will 
charge  from  one  to  ten 
three-cell  storage  batteries 
from  a  11 5- volt,  60-cycle, 
alternating-current  circuit. 
A  compensator  with  fifteen 
taps  is  part  of  the  device 
and  a  dial  switch  for  in- 
stantly adjusting  voltage  ac- 
cording to  the  number  of  batteries  to  be 
charged.  Amperage  can  be  regulated  be- 
tween  limits  of  1  and  6  amp.    A  single 


in  a  3/2  Ft. 
— Particularly 


New  Vacuum  Bulb  Rectifier  with 
Control  Handle  and  Ammeter,  De- 
signed for  Charging  Storage  Batteries. 


three-cell  battery  may  be  charged  by  itself 
or  any  number  up  to  and  including  thirty 
cells.  The  controlling  devices,  including 
ammeter,  switch  and  regulating  handle,  are 
located  on  the  front  of  the  case  as  seen. 


May,  1917 


THE  ELECTRICAL  EXPERIMENTER 


19 


CIVIC  FORUM  MEDAL  FOR 
DR.  BELL. 

Dr.  Alexander  Graham  Bell,  inventor 
of  the  telephone,  before  a  gathering  which 
filled  Carnegie  Hall,  received  the  Civic 
Forum  Medal  of  Honor  for  Distinguished 
Public  Service  on  March  twenty-first. 
This  medal  was  presented  in  1914  to  Maj- 
or-general George  VV.  Goethals  and  in  1915 
to  Thomas  Alva  Edison.  After  many  elo- 
quent speeches  in  his  praise,  Dr.  Bell  re- 
sponded modestly,  endeavoring  to  share  the 
tributes  to  him  with  those  who  have  been 
associated  with  him  in  developing  the  tele- 
phone. < 

"I  may  perhaps  claim  the  credit  of  blaz- 
ing the  trail,"  he  said,  "but  I  am  embar- 
rassed at  all  the  honor  which  has  been 
done  me,  because  so  much  of  it  should  go 
to  the  many  men  who  have  since  improved 
upon  and  extended  its  use — to  such  men 
as  Mr.  Carty  and  his  associates.  Why,  I 
am  not  even  able  to  understand  some  of 
the  mechanism  which  they  have  introduced 
into  the  use  of  the  telephone.  When  they 
telephoned  from  Arlington  and  were  heard 
at  Eiffel  Tower  in  Paris,  I  could  not  see 
how  it  was  done,  nor  could  I  understand 
how  an  operator  in  Hawaii  was  able  to 
pick  up  the  message." 

Dr.  Bell  told  how,  shortly  after  he  got 
the  idea  of  the  telephone  in  1874,  he  had 
called  on  Professor  Henry  at  the  Smith- 
sonian Institution,  who  was  then  recog- 
nized as  the  greatest  authority  on  electric- 
ity in  America.  Professor  Henry  listened 
kindly  to  his  plan,  and  told  him  that  he 
thought  he  had  the  germ  of  a  great  inven- 
tion. 

"I  told  him  that  the  trouble  was  that 
I  did  not  have  enough  knowledge  of  elec- 
tricity," said  Dr.  Bell.  "He  said,  'Get  it.' 
Now  the  fact  is  that,  had  I  known  much 
about  electricity,  I  would  never  have  in- 
vented the  telephone.  I 
would  have  thrown  up  the 
idea  as  wildly  improbable. 
My  study  had  been  that 
of  sound." 


HEINRICH  HERTZ. 
Born  Feb.  22,  1857.       Died  Jan.  1,  1899. 
Inventor  of  Wireless. 

HEINRICH  HERTZ  was  born  on  Feb- 
ruary 22,  1857,  in  Hamburg,  Germany. 
He  received  his  early  training  in  the 
engineering  schools  but  at  the  age  of  twen- 
ty-one he  decided  upon  an  academic  career 


Heinrich  Rudolph  Hertz — Father  of  the  Wire- 
less Telegraph.  Upon  His  Scientific  Re- 
searches and  Practical  Demonstration  of 
Maxwell's  Electromagnetic  Theory,  Marconi 
and  Others  Have  Built  Up  the  Commercial 
System  We  Know  To-Day. 

and  entered  the  University  of  Berlin  as  a 
pupil  of  Von  Helmholtz  and  Kirchoff. 

Of  the  many  gifted  students  of  physics 
who  have  come  forth  from  the  celebrated 


A  NEW  INSULATING 
MATERIAL. 

"Galalith"  is  a  bone-like 
substance  similar  in  many 
respects  to  celluloid.  It  is 
manufactured  from  casein 
and  formaldehyde.  A  solu- 
tion of  casein  is  obtained 
by  treating  skimmed  milk 
with  caustic  alkali,  after 
which  the  solution  is  clari- 
fied and  the  casein  then 
precipitated  by  means  of 
acids  and  filtered.  The 
water  is  then  extracted 
under  pressure  and  the 
product  slowly  dried  over 
a  period  extending  several 
weeks.  The  product  ob- 
tained is  casein  plate, 
which  is  treated  by  thoro 
saturation  with  formalde- 
hyde and  dried  again. 
Galalith  is  said  to  be  an 
excellent  insulating  mate- 
rial somewhat  transparent, 
altho  never  completely  so, 
and  of  a  yellowish-white 
horn-like  color.  It  is 
workable  either  in  the  hot 
or  cold  state,  the  cold  gala- 
lith being  softened  by 
treatment  in  hot  water.  It 
is  odorless,  and  much  less 
inflammable  than  celluloid. 
It  cannot  be  made  into  very  thin  sheets. 

Senator  Sheppard  recently  introduced  an 
amendment  to  the  naval  appropriation  bill 
calling  for  $50,000  to  be  expended  in  the 
erection  of  a  radio  station  at  Galveston. 


TO  ALL  RADIO  AMATEURS. 
rrfHE  Department  of  Commerce  of  Washington,  by  its  Secretary,  the  t 
/    Hon.  JVm.  C.  Red  field,  has  kindly  sent  us  the  following  information  j 
of  particular  interest  to  all  amateurs  in  the  United  States  at  the  pres-  J 
ent  time.  I 

Secretary  Redficld  has  issued  orders  that  for  the  present  no  ne"w  licenses 
to  radio  amateurs  will  be  issued  and  the  renewal  of  outstanding  amateur 
licenses  will  be  granted  only  by  the  Department  upon  special  favorable  re- 
ports by  the  radio  inspectors.  (This  refers  to  sending  outfits  only.) 

The  Department  also  informs  our  readers,  reminding  them  of  the  fact 
that  the  operation  of  transmitting  radio  instruments  without  licenses  is  pro- 
hibited under  severe  penalties,  which,  under  the  conditions  of  the  time, 
would  be  exacted  in  the  case  of  those  who  showed  no-  regard  for  the  re- 
quirements of  the  law. 

Up  to  the  time  that  we  go  to  press,  the  Department  has  not  formulated 
final  plans  as  to  what  steps  will  be  taken  in  regard  to  radio  amateurs  as 
a  whole,  and  -whether  they  will  be  allowed  to  continue  to  operate  the  same 
as  before.  It  is  our  personal  impression,  however,  that  no  drastic  steps 
are  likely  to  be  taken  by  the  Government  as  long  as  the  amateurs  cooper- 
ate with  the  Department.  . 

In  view  of  this  we  most  urgently  and  earnestly  request  all  amateurs  at 
the  present  time  to  refrain  from  using  their  transmitting  stations  except  for 
regular  work.  In  other  words,  all  unnecessary  gossip  and  fooling  should  be 
rigidly  suspended  for  the  present,  particularly  the  "Q.R.M."  nuisance  which 
at  best,  only  serves  to  irritate  our  officials,  and  makes  their  work  harder. 
If  amateurs  do  not  voluntarily  stop  such  annoyance  the  Government  will 
certainly  prohibit  the  use  of  all  privately  owned  radio  outfits. 

These  are  no  times  to  use  the  ether  for  a  lot  of  nonsense;  we  all  wish 
to  help  our  country  as  much  as  we  possibly  can  until  normal  conditions  are 
restored  again. 

Always  remember,  that  our  Government  has  granted  the  radio  amateurs 
more  powers  than  any  other  country  in  the  world,  and  in  times  of  stress, 
it  is  up  to  the  amateurs  to  show  of  what  stuff  they  arc  made  by  cooper- 
ating with  our  officials  to  the  fullest  extent  of  their  powers. 

THE  EDITOR. 


Berlin  laboratory,  there  are  probably  none 
who  have  become  so  world-famous  as  Hein- 
rich Hertz.  His  qualities  as  an  investigator 
were  speedily  recognized  by  Von  Helm- 
holtz, who  urged  him  while  still  a  student, 
to  undertake  the  solution  of  the  prize  prob- 


lem proposed  by  the  Berlin  Academy  of 
Sciences  in  1879. 

From  1880  to  1883  Dr.  Hertz  was  an  as- 
sistant in  Von  Helmholtz's  laboratory;  he 
then  lectured  for  two  years  as  instructor  at 
Kiel.  From  1885  to  1889,  he  was  professor 
of  physics  in  the  Polytechnische  of  Karls- 
ruhe. In  the  latter  year  Clausius,  a  pro- 
fessor of  this  institution,  died,  and  Hertz 
was  selected  as  his  successor  in  the  Univer- 
sity of  Bonn,  where  he  spent  the  few  re- 
maining years  of  his  life. 

Hertz's  career  as  a  scientific  investigator 
covered  a  period  of  scarcely  more  than  ten 
years,  during  which  time  he  publisht  thirty- 
six  papers.  Of  these,  a  series  of  thirteen 
which  appeared  in  Wiedemann's  Annalen, 
were  upon  the  subject  with  which  his  name 
will  forever  be  connected,  the  laws  of  the 
propagation  of  electro-magnetic  induction 
thru  space.  Of  this  great  work,  which  af- 
forded a  complete  experimental  verification 
of  the  Maxwellian  theories  concerning  elec- 
tro-magnetism and  the  relation  of  electric- 
ity to  light,  there  is  no  need  to  speak  of  its 
great  importance  to  the  scientific  world. 

The  importance  of  Hertz's  contributions 
to  this  great  subject  received  instant  recog- 
nition. It  would  indeed  be  difficult  to  find 
any  other  instance  in  which  researches  bear- 
ing upon  a  most  subtle  and  difficult  ques- 
tion, and  absolutely  devoid  of  basic  elements 
of  a  utilitarian  or  even  of  a  popular  char- 
acter, having  secured  to  their  author  such 
sudden  fame.  In  addition  to  the  recogni- 
tion of  those  wno  were  able  to  appreciate 
his  work,  Hertz  received  the  acclamations 
of  the  entire  world  of  thought.  Fortun- 
ately, he  possest  a  nature  of  such  complete 
simple-mindedness  that  his  sudden  rise  into 
a  position  akin  to  notoriety  had  no  effect 
upon  him.  The  unassuming  bearing  which 
had  always  characterized  him  remained 
with  him  to  the  end. 

  „,„„„■„-„„„..«      In   delightful  harmony 

I  with  the  genuine  and  sim- 
1  pie  nature  of  the  man 
were  his  surroundings  in 
the  quiet  university  town 
of  Bonn.  His  laboratory 
was  situated  in  the  apart- 
ments formerly  occupied 
as  a  dwelling  by  Clausius 
in  a  wing  of  the  old  pal- 
ace. Since  electricity  has 
become  utilitarian,  we  find 
it  associated  everywhere 
with  moving  machinery 
and  with  the  rush  and 
bustle  of  modern  indus- 
trial life,  but  in  Hertz's 
laboratory,  there  was  noth- 
ing to  suggest  the  science 
of  electro-technics.  The 
place  seemed  to  breathe 
that  spirit  of  academic  re- 
pose which  to  the  inmates 
of  the  present  day  must 
have  seemed  to  have  van- 
ished altogether  from  the 
world.  What  might  such 
a  man,  in  such  an  en- 
vironment, have  not  been 
able  to  achieve,  had  he 
lived  ? 

The  promulgation  of 
the  theories  of  Dr.  Hein- 
rich Hertz  in  connection 
with  Wireless  waves, 
stimulated  universal  inter- 
est all  over  the  world, 
which  led  to  their  use  in 
the  propagation  of  intelli- 
gence thru  free  space. 
In  1892,  Hertz's  re- 
searches upon  the  electric  waves  were  gath- 
ered together  in  a  volume  under  the  title 
"Untersuchungen  ueber  die  Ausbreitung  der 
Elektrischen  Kraft."  Almost  on  the  day 
of  his  death,  another  excellent  translation 
of  Hertz's  researches  appeared. 


20 


THE  ELECTRICAL  EXPERIMENTER 


May,  1917 


L 


IEUTENANT  Commander  Par- 
ker, U.S.  submarine  'F-609.'  Our 
torpedoes   useless.     Proceed  at 
once  and  see  if  you  can  do  any- 
thing.   Enemy's  defense  perfect. 
Admiral  Gregg,  U.S.N., 
Commanding  Flotilla." 
T  glanced  up  from  reading  this  message, 
scrawled  on  a  scrap  of  paper,  to  ask  Park- 
er what  it  meant,  but  he  was  not  there.  I 
heard   him    in    the    forward  compartment 
issuing  orders  in  his  rapid-fire  manner. 

It  puzzled  me,  this  brief  dispatch  which 
Parker  had  translated  from  the  muddle  of 
code  words  that  had  come  in  over  my 
wireless.  Could  it  be  that  the  great  fleet 
of  submarines  now  in  mid-Atlantic,  sup- 
posed to  be  torpedoing  the  enemy's  fleet 


"Eddy  Currents" 

By  C.  M.  ADAMS 

we  went  out,  thirty-two  knots  an  hour, 
headed  for  the  open  sea. 

As  we  went  I  picked  up  a  message  with 
my  wireless  which  seemed  to  be  related  to 
the  information  in  the  code  message  Billy 
had  received.  It  was  a* press  dispatch  and 
read : 

"There  is  a  report  that  the  defensive 
submarine  flotilla  which  was  to  meet  the 
imperial  fleet  in  mid-ocean,  is  helpless  be- 
cause of  the  excellent  defense  of  the  im- 
perial fleet  against  torpedo  attack.  The  re- 
port says  that  the  submarines  have  dis- 
charged every  torpedo  aboard  and  have  not 
damaged  a  single  enemy  ship. 

"The  imperial  fleet  was  reported  by  aero- 
scouts  to  be  of  sixteen  battleships,  to- 
gether with  eight  destroyers  and  followed 


by  our  navy  with  its  present  equipment. 
How  could  we  save  our  country  from  the 
invader?  How  could  we  stay  off  the  de- 
feat which  seemed  iminent  when  that  won- 
derfully trained  army  got  into  action 
against  our  meager  forces? 

I  voiced  these  sentiments  when,  about 
nine  o'clock  I  found  Billy  standing  beside 
the  conning  tower  on  the  open  deck,  look- 
ing forward  over  the  double  wave  that 
marked  our  bows. 

I  felt  free  to  ask  Billy  Parker  much,  for 
we  had  been  old  classmates  at  the  Tech. 
school  before  he  went  into  his  electrical 
engineering  work  and  I  drifted  off  into 
mine,  not  seeing  each  other  until  I  dropt 
into  this  craft  as  its  wireless  operator 
when  the  call  came  to  me  from  the  navy. 


Once  Again  He  Called  to  Start  the  Alternator.    The  Hum  of  the  Machine  Sounded  and  as  Before  the  Switch  Was  Deprest. 

and  Found  That  It  Was  Held  Down  Six  and  a  Half  Minutes. 


I  Timed  It  Now 


as  it  tried  to  approach  our  shores,  had  failed 
in  its  mission?  Were  the  new  powerful 
torpedoes,  loaded  with  hundreds  of  pounds 
of  high  explosive,  and  the  great  mechani- 
cal fish  which  launched  them,  useless  as 
far  as  defense  was  concerned?  I  wanted 
to  ask  Billy  Parker  these  and  many  other 
questions  but  he  was  busy. 

An  hour  after  this  message  had  .-ome 
buzzing  in  we  cast  off  our  moorings  and 
were  slipping  out  thru  the  harbor  dotted 
with  hurrying  navy  craft.  We  did  not  at- 
tract any  unusual  attention,  for  submarines 
were  quite  common  sights  in  these  times. 
Soon  we  past  Sandy  Hook,  thru  the  line 
of  patrolling  cruisers,  then  out  into  the 
open  sea.  Our  turbines  were  purring 
smoothly  and  our  driving  motors  were 
spinning  like  great  smooth-running  tops  as 


by  twenty  transports  carrying  the  invading 
army.  There  are  also  several  enemy  aero- 
planes which  accompany  the  enemy  fleet." 

Evidently  something  was  wrong  with  the 
defense  planned  by  the  navy  officials.  The 
fifty  great  under-sea  craft  were  not  doing 
their  duty,  which  had  been  to  sink  as  many 
of  the  invader's  ships  as  possible.  I  puz- 
zled over  this  as  I  sat  about  waiting  for  my 
call  and  wondered  what  we  would  do  now 
that  our  chief  defense  had  gone. 

What  would  happen  when  the  army  in 
those  twenty  transports  landed  on  our 
shore,  unprotected  save  by  the  scanty  coast 
defense  guns,  made  scantier  by  the  appro- 
priation for  submarines,  and  met  our  vol- 
unteer army  in  a  pitched  battle?  This  truly 
was  a  surprise,  an  overwhelming,  unex- 
pected contingency  which  could  not  be  met 


Wireless  operator  was  all  I  was  good  for, 
owing  to  my  lame  leg. 

"What  will  happen  now  that  our  sub- 
marines are  helpless?"  I  asked. 

"It's  up  to  the  coast  defense  and  the  fleet 
if  we  can't  stop  them,"  he  said,  looking 
away  ahead  where  the  sea  rolled  under  the 
faint  stars. 

Billy  confided  in  me.  His  showing  me 
the  translated  code  message  proved  that. 
But  this  was  a  new  turn. 

"If  we  can't  stop  them?"  I  repeated 
blankly. 

It  had  not  occurred  to  me  that  we  were 
going  to  try  to  stop  them  at  all.  I  did  not 
know  why  we  were  going,  but  it  seemed 
obviously  impossible  for  us  to  do  anything 
in  that  direction  when  the  rest  of  the  sub- 
marines had  failed. 


May,  1917 


THE  ELECTRICAL  EXPERIMENTER 


21 


"Yes,  if  we  can't  stop  them,"  he  repeated 
after  me. 

"Why,  we  won't  be  any  better  than  the 
rest  of  them.  That  torpedo  defense  is 
too  good,"  I  argued. 

"Who>  said  anything  about  torpedoes  at 
all?"  he  demanded,  wheeling  and  staring 
at  me  aggressively.  , 

"Well,  we're  only  a  sub- 
marine," I  retorted.  — 

"Does  that  mean  that 
we  necessarily  have  to  use 
torpedoes?"  he  countered. 


netic  coil  mounted  on  a  revolving  and  in- 
clined carrier.  This  coil  is  shaped  and 
wound  so  that  its  lines  of  force  are  kept 
within  a  very  small  area,  in  this  case  about 
one  and  three  tenths  square  feet.  Conse- 
quently when  a  metal  object  passes  thru 
this  relatively  intense  field,  the  induced 
current  in  the  metal  object  will  be  sufficient 


don't  wei 


I 


"Why, 
asked. 

"We  haven't  a  thing 
that  resembles  a  torpedo 
on  this  boat  except  the 
shells  for  that  three-inch 
gun  under  the  deck,  and 
they  will  be  about  as  ef- 
fective against  a  battleship 
as  birdshot  against  an 
elephant." 

I  stared  at  him  a  long  m^^^^^^^^ 
time  then.    He  was  seri-  — 
ous  as  I  could  see,  even 
in  the  starlight,  but  he  was  not  lucid. 

"Well,  how  are  we  going  to  get  them 
then?"  I  asked,  thinking  that  this  natural 
question  was  expected  of  me. 

"I'll  show  you,"  he  answered,  and 
stept  down  the  ladder  leading  below. 

I  made  to  follow. 

"No,   stay  there,"   he  commanded. 

I  did,  leaning  against  the  steel  conning 
i  tower.  A  moment  later  I  heard  the  sound 
of  mechanism  close  to  my  head  and  glanc- 
ing up  I  saw  something  appear  above  the 
conning  tower.  I  climbed  upon  the  low 
rail  and  looked  up  to  see  what  it  was. 

The  steel  plates  had  opened  in  the  cen- 
ter and  from  the  opening  had  emerged 
a  hemispherical  object,  made  of  what  ap- 
peared to  be  very  heavy  glass  and  measur- 
ing about  three  feet  in  diameter.  Inside 
it  was  what  looked  to  be  a  small  mechani- 
cal device  which  seemed  to  run  on  a  small 
circular  track. 

I  was  busy  examining  the  device  when 
I  heard  Parker  beside  me. 

"That,"  he  said,  "Is  the  Feeler." 

"The  feeler?"  I  repeated,  this  was  new 
to  me. 

"Yes,  the  feeler,  a  device  that  will  locate 
any  ship  within  ten  thousand  yards,  with- 
out any  part  of  our  boat  being  seen." 

I  looked  at  the  device  again  with  in- 
creased interest.  I  could  not  see  anything 
distinctive  about  it. 

"Don't  you  see  how  it  works?"  Parker 
asked. 

"No,  I  can't  say  that  I  do,"  I  admitted. 

"Come  on  down  in  the  control  room  and 
I'll  show  you." 

He  led  the  way  down  the  ladder  and 
we  went  into  the  little  box  of  a  room  under 
the  conning  tower  where  one  is  afraid  to 
lean  against  the  wall  for  fear  of  starting 
or  stopping  something  necessary  to  the 
life  of  the  boat. 

He  picked  out  a  glass  case  from  among  the 
litter  of  instruments  on  the  walls  and 
pointed  it  out  to  me.  It  was  not  a  very 
big  case.  In  it  were  three  dials,  an  elec- 
tric lamp  and  below  it  were  three  small 
control  wheels.  It  looked  very  much  like 
the  other  dials  and  wheels  so  thick  about 
me,  and  was  distinguished  only  by  the 
word  "Feeler"  on  the  case. 

"This  device,"  he  said,  "works  on  the 
principle  of  electro-magnetic  induction. 
You  know  what  that  is,  the  setting  up  of 
a  current  in  something  that  cuts  the  field 
of  force  caused  by  a  magnet.  Well,  up 
there  in  that  glass  case  which  will  stand 
any  pressure  the  boat  hull  will,  is  a  mag- 


"^^"E  have  publisht  a  great  many  stories  in  the  past,  but  we  do  not 
hesitate  to  state  that  "Eddy  Currents"  is  one  of  the  very  cleverest 
we  have  ever  printed.  Not  only  is  it  a  rattling  good  story,  but  the  scheme 
is  so  plausible  that  we  venture  to  prophesy  that  it  will  be  actually  tried 
in  the  not  too  distant  future.  And  then,  the  submarine  will  earn  its 
adjective  "deadly"  in  the  fullest  sense  of  the  term. 


to  make  a  difference  in  the  load  on  the 
coil.    You  see  that  don't  you?" 

I  did.  That  was  perfectly  plain  sailing, 
electrically. 

"Well  then,  when  this  load  comes  on, 
the  lamp  lights  up  as  a  signal,  and  this 
dial  here  which  is  really  a  calibrated  gal- 
vanometer, shows  how  far  away  the  ob- 
ject is." 

He  pointed  to  one  of  the  three  dials 
which  1  had  noticed  was  calibrated  in 
yards. 


IN  THE  JUNE  "E.  E." 

An  interview  with  Thomas  Alva 
Edison,  including  some  new  photo- 
graphs of  the  famous  inventor. 

Electricity  and  Life  by  Dr.  Fred- 
erick Finch  Strong.  Part  III  of 
this  interesting  and  valuable  series. 

Woman's  place  in  the  Wireless 
game  —  A  page  of  female  radio 
operators  who  have  made  good. 

The  How  and  Why  of  Radio  Ap- 
paratus.    Part    IV.     Spark  Gaps. 

The  Calculation  and  Measure- 
ment of  Inductance.  Part  III  of 
this  valuable  series  by  H.  Winficld 
Secor  and  Samuel  Cohen. 

Another  gripping  electrical  tale — 
"In  the  Way"  by  C.  M.  Adams. 
Don't  miss  it! 

Feature  Article — "Electricity's  Aid 
to  the  Fair  Sex" — of  interest  to 
everyone. 

Building  a  High  Frequency  Alter- 
nator for  use  in  Radio  by  S.  Cohen. 

Experimental  Physics.  Fifth 
Paper  by  John  J.  Furia,  A.B.,  M.A. 

An  Electric  Player  for  Tuba- 
phones. 

A   home-made  electric  searchlight 
for  the  amateur  by  Frank  M.  Jack- 
■  son. 


"What  are  the  other  dials  for?"  I  asked. 

"They  are  to  give  the  angle  of  the  coil, 
both  in  the  horizontal  and  vertical  planes. 
You  see  both  are  calibrated  that  way. 
These  wheels  here  turn  the  coils  about 
and  raise  and  lower  them,  and  this  third 
wheel  operates  the  mechanism  which  raises 


the  coils  clear  of  the  conning  tower." 

I  saw  then  the  whole  perfect  simplicity 
and  accuracy  of  the  device.  I  marveled  at 
it. 

"Then  you  can  run  under  water  with- 
out even  a  periscope  exposed  and  locate 
the  exact  position  of  the  enemy,"  I  said. 

"Exactly,  you  understand  it  perfectly,' 
he  replied. 

— — — — — — -         "Then  you  can  aim  your 

~~"^™"™""~"—       torpedo  with  accuracy,"  I 
went  on. 

"Torpedo !"  he  snorted 
with  an  exasperated 
frown.  "Didn't  I  tell  you 
that  we  didn't  have  one  of 
those  antiquated  devices 
aboard  this  craft?" 

"But,"  I  went  on,  "you 
must  have  something  to 
sink  the  enemy  after  lo- 
cating him." 

"We  have,"  he  said,  his 
face     brightening  hope- 

_ —  fully- 

"Well,  what  is  it?"  I 
asked,  puzzled. 

"Look  here,  Dick  Hartman,"  he  said  in 
mock  seriousness,  "do  you  mean  to  tell 
me  that  after  seeing  this  feeler  work,  you 
can't  understand  how  we  could  sink  a  ship? 
You,  a  graduate  of  the  best  technical  school 
in  the  country  and  a  practical  electrical 
engineer,  can't  understand  that?" 

I  contest  that  I  did  not. 

"Then  you're  either  asleep  or  haven't  the 
least  trace  of  imagination,"  he  said,  turn- 
ing away  in  disgust. 

"Well,  how  do  you  do  it  anyhow?"  I 
asked. 

"I'm  not  going  to  tell  you.  I'll  let  you 
find  out  for  yourself  first,"  he  retorted 
with  a  show  of  his  old  boyish  perversity, 
and  walked  into  his  room  and  left  me 
wondering  in  front  of  the  feeler  dial. 

But  I  could  not  follow  his  line  of  reas- 
oning to  its  end.  I  thought  of  it  as  I  tried 
to  sleep  that  night,  while  the  motors 
thrust  us  forward  and  our  long  hull  swayed 
gently  as  we  topt  the  crests  and  fell  into 
the  hollows.  I  puzzled  over  it  as  I  sat 
at  my  instruments  and  waited  for  my  call, 
or  anything  else  my  receivers  could  pick 
from  the  ethereal  vibrations  about  us.  But 
I  could  make  nothing  of  it.  I  could  see 
no  way,  no  means  by  which  wc  could  sink 
an  enemy  ship  with  this  curious  little  feeler 
device  which  with  all,  was  exactingly  ac- 
curate. 

All  that  night  we  ran  and  all  the  next 
day.  I  did  not  ask  Billy  any  more  about 
our  boat.  Pride  perhaps  kept  me  from 
doing  this,  and  impatience  at  my  own  lack 
of  perspicuity  and  imagination.  And  then 
too  I  was  busy  with  my  own  work  and 
other  things  that  came  up,  which  had  to 
be  done  in  the  crowded  under-sea  craft. 

I  prowled  about  it  in  what  spare  time  I 
had,  trying  to  see  what  I  could  between 
tricks  at  my  table.  I  found  that  it  was 
quite  the  usual  large-sized  submarine,  of 
which  the  navy  had  an  even  hundred  not 
counting  ours.  It  was  driven  by  electric 
motors  supplied  by  turbine  driven  genera- 
tors forward.  It  was  provided  with  the 
usual  gas  absorption  system  which  made 
it  possible  to  run  under  water  with  our 
steam  power,  without  discharging  any  ex- 
haust gases;  this,  the 'first  important  in- 
vention of  the  Naval  Consulting  Board.  But 
I  found  the  forward  torpedo  room  locked 
and  none  on  board  had  gone  into  it  since 
they  had  been  on  board,  none  save  the 
chief  engineer,  Dickenson,  a  man  from 
Parker's  own  electrical  company,  which 
had  built  this  curious  boat  and  sent  it  out 
(Continued  on  page  66) 


LIBRARY 


11  <?  patent  nrri/c 


22 


THE  ELECTRICAL  EXPERIMENTER 


May,  1917 


118  VOLTS  CAN  KILL. 

The  Ontario  Electrical  Inspection  De- 
partment of  the  Hydro  Commission  are  out 
hot  foot  after  delinquents  who  try  to  work 
in  jobs  without  permits  and  convictions  are 
being  rendered  every  week,  says  a  writer  in 
the  Electrical  Safety  Magazine. 


Never  Touch  Electric  Light  Fittings  or  Wir- 
ing  While  Standing    In   a   Bath-Tub  or  On 
Damp  Floor,  as  the  Consequences  May  Prove 
Fatal. 

One  person  is  to  come  up  before  the 
board  for  refusing  inspector  admission  to 
premises  and  others  for  not  returning  to 
remedy  defects  on  jobs  before  expira- 
tion of  inspectors'  notices. 

In  the  City  of  Toronto,  in  the  month 
of  October,  a  young  man,  nineteen  years 
of  age,  was  in  the  bath-tub  and,  so  far 
as  his  parents  knew,  he  was  enjoying 
the  harmless  and  healthful  pastime  im- 
mensely, judging  by  the  sounds  of 
splashing  and  rubbing  emanating  from 
the  keyhole. 

The  happy  sounds  were  suddenly  in- 
terrupted by  a  deathly  shriek,  and  his 
parents  upon  breaking  into  the  room, 
found  him  doubled  up  with  the  coils  of 
a  long  portable  lamp  cord  wound  round 
him  and  the  portable  lamp  in  the  bath. 
The  lamp  was  an  ordinary  brass  desk 
lamp  provided  with  the  silk  cord. 

The  cord  was  worn,  showing  bare 
copper  spots.  What  he  was  doing  with 
a  lamp  in  the  bath  no  one  knows. 

The  bathroom  was  provided  with  a 
brass  bracket  well  up  above  the  bath  with 
a  portable  socket. 

Test  revealed  that  118  volts,  25  cycle  cur- 
rent was  used,  one  side  grounded,  the  fix- 
ture itself  clear  of  ground  and  well  insu- 
lated from  both  the  grounded  and  un- 
grounded sides  of  the  circuits. 

The  investigations  show  that  he  was 
killed  by  coming  in  contact  with  brazed 
cord  carrying  118  volts,  25  cycle  current. 

This  proves  two  things:  First,  that  118 
volts  can  kill,  and  secondly,  that  indif- 
ference to  bare  spots  on  cord  is  dangerous. 

One  quarter  of  a  dollar  spent  on  renew- 
ing this  cord  would  have  saved  a  young 
life,  a  doctor's  bill,  an  undertaker's  bill, 
and  the  parents'  grief.  Is  it  not  worth 
while?  Safety  First!  should  be  the  slo- 
gan of  every  user  of  electric  service, 
whether  for  half  a  dozen  lamps  or  for  a 
large  factory.  Again — when  you  stand  on 
a  damp  or  wet  floor  or  in  a  bath-tub,  don't 
touch  an  electric  switch  or  fixture! 


their  entire  life  a  pair  of  these  shoes,  the 
manufacturer  states,  will  provide  the  wear- 
er protection  against  circuits  at  pressures 
up  to  20,000  volts  and  will  not  cause  the 
discomforts  of  many  of  the  rubber  soles. 

The  shoes  are  molded  by  a  process  simi- 
lar to  that  used  in  making  automobile  tires. 
The  shoes  contain  no  cement  and  have  no 
seams,  but  are  vulcanized  into  a  solid  piece 
under  high  pressure  on  aluminum  molds. 
No  hand  work  is  employed  in  the  process. 
This  method  of  manufacture  makes  it  im- 
possible for  the  completed  shoe  to  peel  or 
come  apart  and  prevents  injury  from  oil, 
gasoline  or  grease. 

In  order  that  the  shoes  may,  in  the  inter- 
est of  safety,  be  distinctive,  they  are  all 
made  exactly  alike  with  brown  heels,  white 
soles,  brown  vamps  and  black  tops.  The 
white  soles  are  made  of  a  rubber  composi- 
tion like  that  employed  in  certain  types  of 
coal  miners'  shoes,  which  have  been  found 
to  give  eighteen  months  of  constant  wear. 
When  this  white  sole  wears  thru,  a  layer 
of  red  rubber,  which  will  itself  with- 
stand a  pressure  of  20,000  volts,  is  exposed 
The  appearance  of  the  red  rubber  is  a  sig- 
nal or  reminder  to  the  wearer  that,  altho 
his  shoes  still  will  withstand  20,000  volts, 
a  new  half  sole  should  be  immediately  ce- 
mented or  vulcanized  in  place. 

The  brown  rubber  also  extends  under  the 
white  sole.  It  is  this  piece  of  material 
which  is  capable  of  withstanding  high  po- 
tentials.   One  of  these  shoes,  when  tested 


S(Vtf!er/Vogf//f/7or?re<?je 


insu/afed  so/e  of  red 
rubber  tested  eo.ooo  v\ 


proof <?/?d /toffee fed  6y 
tiejt /tor  cofd 

(//>//>#  embedded m 
itt/tier  to  prevent 
jbjor/)t/o/?  <f/77o/3fi/re 


Outer s//r&ceqffouob 
retfruMev-  fejfedto  ^ 
c~o  000  voffs  J?  Z//7Cfe3 
o/irsterj/fer  }<ooeo 
///p/jAed 


Outer  sofe  wb/tejvt . 
rei/sfwg  vwatff/zeq  c//s 
trejd rubber  wfar/i  ir/fb- 
sbnds  3QOOO  voftj 


L  tfo/7-moafi/re  I  

Jbsorbw?  casAroo 

ffeet  of  tougti) 
ifear-res/stir?g  rubier 


Remarkable    New    Shoe    for    Lineman    Which  Is 
Capable  of  Withstanding  20,000  Volts.     Note  That 
No  Nails  Are  Used. 

in  the  laboratories  of  the  Edison  Electric 
Illuminating  Company  of  Boston,  under  the 
direction  of  the  accident  prevention  com- 
mittee of  the  National  Electric  Light  Asso- 
ciation, showed  the  following  characteris- 
tics : 

"Side  of  shoe,  dry,  punctured  at  31,500 
volts,  and  again  at  34,000  volts ;  sole  of 
shoe  between  electrodes  in  oil  punctured  at 
55,000  volts;  20,000  volts  applied  from  salt 
water  to  salt  water  for  one  minute  and 
30,000  volts  applied  from  salt  water  to  salt 
water  for  forty-five  seconds  did  not  punc- 
ture the  rubber." 


point,  were  about  seven  feet  above  the  lo- 
comotive, and  current  is  sent  thru  them 
at  a  pressure  of  11,000  volts,  25  cycles. 

Directly  over  the  engine,  which  was  giv- 
ing off  a  medium  black  smoke,  the  air 
seemed  to  flicker  at  the  rate  an  electric 
light  would  if  connected  to  a  25  cycle  cir- 
cuit. This  *vas  only  noticeable  when  the 
quality  of  the  smoke's  carbon  element  was 
just  right.  That  this  flickering  was  not  due 
to  heat  waves  I  proved  by  the  fact  that 
objects  when  looked  at  thru  heat  waves 
seem  to  bend  or  wave  from  side  to  side  and 
move  upward,  while  objects  seen  thru  this 
vibrating  air  did  neither,  and  when  the 
quantity  of  carbon  decreased  as  the  wind 
blew,  the  flickering  effect  disappeared. 

The  cause  of  this  phenomena  I  attribute 
to  the  attraction  and  repulsion  of  the  car- 
bon particles  in  the  smoke  and  as  the  cur- 
rent reversed  they  were  drawn  upward  and 
downward  for  a  very  short  distance,  while 
being  dissipated  into  the  atmosphere.  The 
effect  was  not  noticed  a  few  inches  above 
the  wire.  The  weather  on  January  tenth 
was  slightly  hazy,  with  no  sun  at  3.30  p.m., 
when  this  effect  was  noticed.  In  bright 
sunlight  it  could  not  have  been  seen.  If 
my  explanation  is  in  error  I  shall  be  pleased 
to  hear  the  views  of  some  of  your  technic- 
ally inclined  readers. 

MAKE  YOUR  PHOTO  PRINTS  BY 
ELECTRICITY. 

The  electric  photograph  printer  illustra- 
ted has  been  brought  out  for  both  pro- 
fessional and  amateur  use.    A  feature 
of  the  device  is  an  automatic  switch 
which  is  operated  only  when  full  pres- 
sure is  placed  on  the  pad.    The  pressure 
pad  is  placed  in  position  by  a  hand  lever 
which  controls  the  automatic  switch,  the 
'light  being  turned  on  only  when  full 
pressure  is  exerted  on  the  pad.  The 
light  is  -turned  off  before  pressure  on  the 
pad  is  released,  thus  avoiding  any  blur- 
ring in  the  prints  and  assuring  absolute, 
contact.     A   locking   device    is  provi- 
ded which   relieves    the    operator  of 
the  necessity  of  maintaining  pressure  on 
the  lever  during  the  exposing  period. 
With  a  slight  grip  on  the  release  catch, 
the  lever  can  be  freed.    A  locking  de- 
vice is   also   provided,   permitting  the 
white  light  to  be  turned  on  and  the  pres- 
sure pad  elevated  to  permit  accurate  ad- 
justment of  masks  or  vignettes.    In  the 
light  box  of  the  smaller  printer  are  one 
ruby  and  four  clear  incandescent  lamps, 
and  in  the  larger  one  there  are  one  ruby 
and   six   clear   incandescent   lamps.  The 
printers  are  designed  to  take  100-watt  gas- 
filled  lamps. 


ELECTRICITY  LIGHTS  NEW  PIPE. 

An  electrically  ignited  pipe  which  lights 
the  tobacco  at  the  bottom  of  the  bowl  in- 
stead of  at  the  top,  thus  avoiding  the  col- 
lection of  moisture  in  the  stem,  is  the  new- 
est in  smokers'  inventions. 


A  LINEMAN'S  SHOE  THAT  WITH- 
STANDS 20,000  VOLTS. 

A  leading  American  maker  of  lineman's 
protective  devices,  which  for  several  years 
has  been  marketing  protective  shields  to 
cover  wires  and  cross-arms  where  men  are 
working,  has  now  developed  an  insulat- 
ing shoe  for  electrical  workers.  Thruout 


PECULIAR  ELECTRICAL 
PHENOMENA. 
By  Walter  J.  Howell. 

While  standing  about  one  hundred  feet 
away  from  the  tracks  of  the  New  York, 
New  Haven  and  Hartford  Railway  January 
10,  1917,  a  large  steam  engine  pulling  a 
heavy  freight  train  past  at  the  rate  of  five 
to  eight  miles  per  hour.  The  railroad  is 
electrified  by  overhead  wires,  which,  at  this 


Electrically  Illuminated  Photograph  Printer 
Equipt  with  Automatic  Switch  Actuated  By 
Printing  Frame. 

The  printer  is  being  made  in  two  sizes — 
8  in.,  by  10  in.,  and  11  in.,  by  14  in. 


May,  1917 


THE  ELECTRICAL  EXPERIMENTER 

™°  RADIO  LEAGUE 


^AMERICA 


H.  Gcrnsback,  Manager 


H  ON  OR  ART  MEMBERS 
CAPT.  WHG.  BUILARD.  U.  S.N.     NIKOLA  TESL A 
PROF.  REGINALD  FESSENDEN.    DR.  LEE  DE  FOREST. 

W.  H.  Kirwan,  Master  of  Radio  Relays 


The  Washington's  Birthday  Relay  Prize  Winners 


WELL,  boys,  you  did  it ;  the 
first  official  Trans-continental 
M.S.G.  (message)  No.  1  from 
the  Mayor  of  New  York  to 
the  Mayor  of  Los  Angeles, 
went  thru  with  the  customary  speed  and 


Mr.  Edward  B.  Duval!,  Who  with  Mr.  A.  P. 
Smith,  Operating  Station  "3AK,"  Baltimore, 
Md.,  Won  "First  Prize"  in  the  Washington's 
Birthday  Relay. 

reliability  of  all  the  Relay  messages  we 
have  worked  on.  The  special  stations 
sent  the  westbound  message  from  New 
'York  on  this  night  from  2  ZK 
at  New  Rochelle,  using  8  YI,  9 
XM  and  9  ZF  to  6  EA,  which 
last  station  is  in  Los  Angeles, 
Cal.  Considering  the  time,  one 
and  one-half  hours,  and  the 
great  "QRM"  (interference) 
and  the  repeating  of  message 
on  account  of  misspelt  words, 
it  was  truly  wonderful. 

The  westbound  message  used 
special  stations  only  and  was 
as  follows : 

To  the  Mayors  of  Los  Ange- 
les, Cal.,  and  Seattle,  Wash.: 
On  behalf  of  New  York  City, 
I    send    cordial    greetings  to 
Los  Angeles  and  Seattle,  and 
best  wishes  for  the  success  of 
the  Radio  System. 
(Signed) 

John  Purroy  Mitchel, 
Mayor  of  New  York. 
Thousands  of  amateurs  cop- 
ied this  message  with  varying 
degrees  of  exactness  thruout  the  country, 
as  four  heaping  bushels  of  letters  have 
shown.    This  was  the  first  relay  attempted 


By  W.  H.  KIRWAN,  (9XE) 
Master  Radio  Relays,  Radio  League  of  America 

by  the  writer,  the  necessary  notices  of 
which  were  publisht  in  this  magazine. 
Some  of  you  did  not  hear  about  the  Re- 
lay because  you  are  not  regular  subscrib- 
ers. Let  this  be  a  lesson — Get  your  name 
down  so  that  you  will  receive  your  maga- 
zine promptly  and  regularly. 

Now,  here  comes  the  sad  part.  You 
will  see  "by  the  papers,"  that  on  this  night 
we  had  good  radio  weather  as  far  as  the 
Rockies,  but  the  writer  had  studied  the 
weather  man  and  looked  for  trouble  south- 
west and  west,  and  we  had  it !  A  healthy 
young  cyclone  was  dancing  merrily  over 
Texas,  Arizona,  New  Mexico  and  Califor- 
nia, and  the  tail  end  of  a  regular  old-time 
"QRM"  storm  was  making  life  miserable 
for  the  boys  in  the  war  west,  but  with  it 
all,  6  EA  got  the  message  direct  from  9 
ZF.  6  DM,  who  volunteered  to  help  6 
EA,  put  on  full  power  and  promptly  blew 
the  fields  of  his  gap  motor,  leaving  6  EA 
to  do  the  honors  and,  by  golly,  he  did. 

Seefred  Bros.,  delivered  this  message  to 
the  Mayor  of  Los  Angeles,  and  promptly 
received  his  reply,  but  QRM  and  QRN 
were  so  bad  by  this  time  that  it  was  a 
physical  impossibility  to  get  it  thru  to  9 
ZF.  6  EA  stuck  to  his  post,  however,  and 
got  the  message  thru  the  next  night,  too 
late  for  9  ZF  to  find  anyone  out  of  bed. 
9  XE  arranged  for  all  eastbound  amateurs 
to  be  on  the  job,  and  the  message  came 
thru  fine,  being  delivered  to  the  Mayor  of 
New  York  by  Mr.  Geo.  C.  Cannon,  2  ZK, 
the  next  morning  early. 

Lots  of  you  kept  me  company  by  stay- 
ing up  all  night  waiting  for  the  return 
message  and  now  you  know  why  it  could 
not  get  back  on  schedule.  The  return  mes- 
sage was  as  follows : 
To  the  Mayor  of  New  York  City: 

On  behalf  of  the  City  of  Los  Angeles, 


sage.      (Signed)    Fred    I.  Woodman, 
Mayor  of  Los  Angeles. 

By  counting  up  the  total  time  consumed 
on  each  message,  we  -call  the  race  between 
Specials   and   Amateurs   a   tie,   with  the 


Radio  Station  "3  AK,"  Baltimore,  Md.,  at  Which  the  Wash 
Birthday  M.S.G.  Was  Successfully  Received  in  Record 


I  return  your  greetings  and  wish  you 
continued  prosperity.  Congratulations  to 
Amateur  Radio  on  the  successful  mes- 


Mr.  A.   P.  Smith,  Joint  Operator  of  Radio 
Station  "3AK,"  and  to  Whom  Full  Share  of 
the  Credit    for    the    Receipt    of    the  Relay 
M.S.G.  Is  Due. 

handicap  of  the  low  wave  length  of  the 
amateurs,  giving  them  a  slight  preference 
for  a  decision  in  their  favor,  but  my  form- 
er contention  still  holds — that 
the  amateurs  are  not  yet  pre- 
pared to  handle  these  trans- 
continental messages  with  as 
great  a  degree  of  certainty  as 
the  Specials,  unless  they  can  get 
together  and  have  emergency 
stations  in  the  long  jumps. 

I  am  not  posing  as  an  expert, 
but  candidly  believe  that  fifty 
miles,  worked  absolutely  sure, 
with  a  great  number  of  relay 
stations,  is  more  reliable  than  a 
few  with  long  jumps,  working 
only  when  the  conditions  per- 
mit. This  is  what  we  propose 
to  do  now  by  organizing  the 
"Q.R.M.  League."  In  it,  there 
will  be  a  chance  for  all  of  you 
to  help  and  not  just  a  few  thru- 
out the  country  who  want  to 
work  every  night,  and  who 
want  you  to  shut  up.  You 
know,  boys,  this  good  old 
U.S.A.  is  a  pretty  big  place  and 
these  Relays  are  run  for  your  benefit,  but 
there  are  some  few  in  this  country  who 
(Continued  on  page  61) 


ington's 
Time. 


24 


THE  ELECTRICAL  EXPERIMENTER 


May,  1917 


Electricity  and  Life 


IN  the  March  number  of  The  Elec- 
trical Experimenter  the  author  point- 
ed out  that  high-frequency  currents, 
when  properly  tuned,  acted  as  "Vital 
Boosters,"  increasing  all  the  functions 
of  the  body  and  helping  it  to  resist  and 


The  Construction  of  High-Frequency  Apparatus  for  Medical  and  Lecture  Use 
By  FREDERICK  FINCH  STRONG,  M.  D. 
Lecturer  on  Electro-therapeutics,  Tufts  Medical  School,  Boston 

(Second  Article) 

The  author  has  interviewed  a  number 
of  the  more  prominent  authorities  on  med- 
ical electricity  and  they  agree  as  to  the 
vitalizing  effects  resulting  from  daily  high 
frequency  treatment. 

Anyone  who  possesses  a  V\  or  l/z  K.W. 
wireless  transformer,  operating  on  110  volt, 
60  cycle  A.C.,  can  easily  construct  an  effi- 
cient high-frequency  outfit  for  medical  or 
lecture  use.  The  complete  equipment  in- 
cludes a  .01  microfarad  glass  plate  con- 
denser, Tesla  coil,  inductance,  spark  gap 
and  electrodes. 

The  Tesla  coil  is  made  as  follows:  (Fig. 
3)  On  a  paper  mailing  tube  2j4"  diam.  and 
14"  long  wind  480  turns  of  No.  34  D.C.C. 
copper  magnet  wire.  Set  up  the  tube  in 
the  lathe,  apply  a  coat  of  orange  shellac, 
spin  on  the  wire,  apply  a  second  coat  of 
shellac  and  allow  to  dry  thoroly.  The 
winding  occupies  twelve  inches,  leaving  a 
margin  of  one  inch  on  each  end  of  the  tube. 
Leads  of  light  auto  (ignition)  cable  are 
^soldered  to  the  ends  of  the  winding.  A 
'.strip  of  waxed,  corrugated  paper  M,  5" 
wide  is  wrapt  around  the  center  of  the  sec- 
ondary tube  and  on  this  is  wound  the  pri- 
mary, consisting  of  four  turns  of  heavy 
high  tension  auto  cable,  and  thoroly  se- 
cured by  tape;  at  least  a  foot  of  cable 
should  project  from  each  end  of  the  wind- 
ing to  form  the  primary  leads.  Place  the 
coil  in  a  wax  tight  box  made  without  nails 
and  embed  it  in  a  mixture  of  four  parts 
rosin  and  one  part  beeswax.  It  is  safer  to 
boil  the  coil  for  an  hour  in  the  insulating 
mixture  before  placing  it  in  the  box.  Coils 
made  in  this  way  by  the  writer  are  still 
giving  good  service  after  fifteen  years  of 
use. 

The  greatest  source  of  trouble  in  a  medi- 
cal high-frequency  outfit  is  the  spark  gap; 
the  one  described  below  is  the  outcome 
of   many  years   experiment.     If  properly 


made  it  will  run  daily  for  months  without 
deterioration.  The  spark  takes  place  be- 
tween two  pieces  of  brass  rod  1%."  diam. 
and  3^4"  l°ng,  turned  and  tapt  as  shown. 
The  sparking  surfaces  are  turned  in  an- 
nular grooves  with  a  60  degree  tool.  If 


Fig.   1.     View  of  the  Strong  Conical  Oudin 
High  Frequency  Coil  Delivering  a  Veritable 
Tree  of  Sparks  Several  Feet  in  Length. 


Fig.  2.     Another  View  of  the  Strong  High 
Frequency  Coil  Producing  a  Perfect  Sheet  of 
Flaming   Sparks  to   a  Grounded  Conductor. 
The  Exciting   Energy  Is  but  1  Kilowatt. 


throw  off  disease.  This  vitalizing  effect  is 
not  due  to  the  mere  liberation  of  heat  in 
the  tissues,  for  it  is  produced  by  the  very 
high-voltage  ( "Tesla")  currents  as  well  as 
by  the  heavy  amperage  ("D'Arsonval")  cur- 
rents from  which  the  thermic  effects  are 
usually  obtained. 

When  the  writer  demonstrated  the  first 
therapeutic  Tesla  Coil  and  the  first  Vacuum 
Electrode — (in  1896  before  a  Boston  Medi- 
cal Society) — and  suggested  that  this  meth- 
od was  destined  to  come  into  general  use 
as  a  vitalizing  agent,  he  was  laughed  at  by 
his  colleagues ;  yet  to-day  there  is  scarcely 
a  well  equipt  physician's  office  in  this  coun- 
try or  in  Europe  that  does  not  contain  some 
form  of  therapeutic  high-frequency  appa- 
ratus. Even  the  barber-shops  of  the  pres- 
ent time  have  their  small  "Violet  Ray"  out- 
fits ;  and  these  are  not  by  any  means  "fakes" 
for  they  produce  real  results,  such  as  the 
relief  of  headache,  neuralgia,  skin  diseases, 
et  cetera. 

Unlike  other  forms  of  electricity,  these 
currents  may  be  administered  to  patients 
with  perfect  safety.  In  twenty  years'  ex- 
perience in  electro-therapeutics  the  author 
has  never  known  of  harmful  results  from 
the  use  of  Tesla  Currents  applied  thru  a 
vacuum  electrode.  The  heavy  amperage 
("D'Arsonval")  currents,  owing  to  their 
deep  thermic  effects,  should  be  used  only 
under  the  direction  of  a  physician.  The 
writer  is  a  firm  believer  in  the  use  of 
Tesla  currents  in  the  home — if  each  mem- 
ber of  the  family  could  receive  ten-minute 
daily  treatments  from  a  small  high-fre- 
quency apparatus,  the  general  standard  of 
health  would  be  greatly  increased.  This 
has  been  demonstrated  in  hundreds  of  cases. 


Conical 
Oud/n  Co/l 


f/g.6 


Details  Are  Given  in  This  Article  for  Con- 
structing a  Reliable  and  Powerful  Oudin  op 
Tesla  High  Frequency  Coll,  Suitable  for  Phy- 
sicians' Use.  This  Type  of  Coil  is  the  Most 
Efficient  Ever  Designed. 


your  lathe  has  an  automatic  cross-feed  you 
may  set  it  to  twenty  turns  to  the  inch, 
and  turn  a  spiral  groove  instead  of  the 
annular  rings.  After  finishing,  the  brass 
pieces  are  heavily  silver  plated  and  mounted 
in  the  usual  manner  as  shown.  (Fig.  4.) 
For  currents  over  J4  K.W.,  a  plate  of  silver 
should  be  soldered  to  the  brass  before  turn- 
ing the  grooves.  This  gap  will  also  give 
greater  efficiency  in  wireless  work  as  com- 
pared with  the  usual  stationary  gap. 

The  connections  for  the  various  parts  of 
the  apparatus  are  shown  in  Fig.  5.  An 
important  feature  is  the  use  pf  an  external 
inductance  or  tuning  coil  "d"  in  series  with 
the  Tesla  coil.  It  consists  of  32  turns  of 
No.  8  bare  copper  wire,  wound  on  a  frame 
8"  diam.,  with  J4"  between  turns.  Edge- 
wise wound  flat  copper  strip  is  better-  but 
more  expensive.  (d  Fig.  8.)  This  coil 
when  used  in  series  with  the  Tesla  primary 
enables  us  to  tune  the  oscillating  system 
in  perfect  resonance  when  the  capacity  of 
the  patient's  body  is  added  to  the  Tesla 
terminal.  Effects  are  produced  which  are 
impossible  with  any  other  method.  The 
beautiful  High-frequency  Effluve  or  brush- 
discharge,  so  valuable  in  treating  pulmonary 
diseases,  and  which  so  few  modern  high- 
frequency  machines  can  produce,  is  obtain- 
able by  the  use  of  this  series  inductance. 
It  may  also  be  used,  by  short-circuiting  the 
Tesla  primary,  as  an  auto-transformer  from 
which  may  be  derived  heavy  "D'Arsonval" 
and  "Diathermic"  currents  as  described  in 
the  next  article  of  this  series. 

For  stage  demonstration  and  public  lec- 
ture work  the  writer  employs  a  large  high- 
frequency  resonator  which  produces  a  tree- 
(Continued  on  page  59) 


May,  1917 


THE  ELECTRICAL  EXPERIMENTER 


25 


Experimental  Physics 


Instructor 

LESSON  FOUR 
GASES  AND  THE  ATMOSPHERE 
(Concluded) 

AIR  expands  when  heated  and  be- 
comes lighter  in  weight.  If  we 
have  a  confined  bodv  of  air  such 
as  in  a  room,  for  example,  and 
there  is  a  source  of  heat  in  the 
room,  the  air  near  the  source  will  expand 


Simple  Apparatus  Comprising   Box,  Candle 
and  Two  Lamp  Chimneys  for  Demonstrating 
the  Principle  of  Ventilation. 

and  become  lighter  and  the  heavier  air  at 
the  top  of  the  room  will  fall,  forcing  the 
lighter  air  upward.  Thus  it  is  that  the  air 
near  the  ceiling  is  always  warmer  than 
that  near  the  floor.  This  shows  the  ne- 
cessity of  opening  a  window  at  both  the 
top  and  the  bottom  for  best  ventilation. 
EXPERIMENT  19— 

Fig.  15  shows  very  simple  apparatus 
which  can  be  made  with  practically  any 
material  available,  for  demonstrating  the 
behavior  of  air  near  a  source  of  heat. 
C,  is  a  box  thru  which  holes  have  been 
cut  to  admit  tubes  (or  glass  lamp  chim- 
neys) B.  A  is  a  lighted  candle.  The 
arrows  show  the  direction  of  the  current 
of  air. 

EXPERIMENT  20— 

An  interesting  experiment  giving  sur- 
prising results  and  having  a  simple  ex- 
planation can  be  performed  by  the  use  of 
a  spool  and  a  visiting  card.  (If  no  visit- 
ing card  is  available,  the  ace  from  a  poker 
deck  which  you  may  have  "up  your  sleeve," 
will  do  very  well.)  Place  the  card  up 
against  the  bottom  of  the  spool  as  in  Fig. 
16-A  and  the  mouth  against  t  e  top  of  the 
spool.  Blow  vigorously  and  then  let  go 
of  the  card.  One  would  naturally  expect 
that  blowing  against  the  card  would  blow 


Closed/ 
end 


Closed;  • 
end 


Open 
end  Y 


Fig.  /<? 


A  Glass  Tube,  Sealed  at  One  End  and  Filled 
with  Mercury,  Will  Support  a  30-inch  Column 
of  Mercury,  Owing  to  Atmospheric  Pres- 
sure Acting  Against  a  Vacuum.  The  Prin- 
ciple of  the  Barometer. 

it  away  whereas  actually  the  card  stays 
fast,  close  to  the  bottom  of  the  spool. 
Sometimes,  when  the  conditions  are  not 


By  JOHN  J.  FURIA,  A.  B.,  M.  A. 

in  Physics  and  Science  Master,  Riverdale  Country 

just  right;  the  card  slides  off  perpendicular 
to  the  direction  in  which  one  blows,  but 
to  avoid  this  a  pin  should  be  stuck  thru 
the  card's  center  and  then  into  the  hole  in 
the  spool  (care  being  taken  not  to  stick 
it  into  the  wood  of  the  spool).  Fig.  16-B 
shows  diagrammatically  what  happens.  The 
air  from  the  mouth  passes  down  the  hole 
in  the  spool  and  out  along  the  upper  sur- 
face of  the  card.  It  is  a  well-known  fact 
that  the  pressure  is  greatest  where  the 
speed  is  least  and  vice  versa.  The  air 
underneath  the  card  is  practically  still, 
while  that  just  above  the  card  is  in  rapid 
motion,  and  hence  the  pressure  against  the 
card  from  beneath  is  greater  than  that 
from  above.  Hence  the  card  tends  to  get 
as  close  to  the  spool  as  possible  and  does 
not  fall. 

EXPERIMENT  21— 

In  the  First  Lesson  we  learned  that  at 
any  depth  in  a  liquid  there  is  a  pressure 
due  to  the  weight  of  the  liquid  above  that 
depth.  We  also  learned  that  air  has 
weight  and  consequently  we  conclude  that 
the  air  (at  the  surface  of  the  earth)  has 
pressure  due  to  the  weight  of  the  air  above 
it.  The  higher  up  we  go,  the  less  air 
there  is  above  us  and  hence  the  pressure 
is  less.  If  one  sucks  in  at  the  stem  of  a 
pipe  (see  Fig.  17)  at  the  bowl  of  which 
is  stretched  a  piece  of  sheet  elastic,  the 
pressure  of  the  air  above  it  pushes  the 
elastic  down.  Suction  is  not  a  mysterious 
force ;  it  is  simply  a  removal  of  the  air 
from  one  side  so  that  the  pressure  from 


/"^  fosifiol)  of  elastic 

 •  ■/  fop  sheet  wlii/e  sucA/i/g 

L    /  out  the  air 

^  ill        F>9- 17 


Removing  the  Air  Within  a  Pipe  Bowl  by 
Sucking  In  Thru  Stem  Allows  the  Pressure 
of  the  Air  to  Push  Elastic  Diafram  Inward. 

the  other  side  can  act  without  being  op- 
posed. Actually,  when  the  air  is  entirely 
removed  from  the  pipe,  the  pressure  above 
the  elastic  sheet  is  fifteen  pounds  on  .each 
square  inch;  i.e.,  the  weight  of  the  col- 
umn of  air  from  the  earth's  surface  1  the 
end  of  the  atmosphere  on  each  square 
inch  of  the  earth's  surface  is  fifteen  pounds. 
A  column  of  water  thirty-three  feet  high 
and  one  inch  square  weighs  fifteen  pounds 
and  a  column  of  mercury  thirty  inches 
high  and  the  same  area,  weighs  the  same 
(mercury  weighs  13.6  times  as  much  as 
water) . 

EXPERIMENT  22— 

Seal  one  end  of  a  narrow  tube  having 
a  diameter  of  about  one-quarter  inch  and 
about  fifty  inches  long.  Fill  the  tube  with 
mercury  and  invert  it  carefully  and  place 
the  open  end  in  a  cup  containing  some 
mercury.  The  mercury  in  the  tube  will 
fall  until  the  height  of  the  mercury  in  the 
tube  is  about  thirty  inches  above  the  level 
of  the  mercury  in  the  cup.  The  same 
level  is  kept  no  matter  how  long  and  how 
wide  the  tube  is.  The  air  pressure  on  the 
cup's  surface  acts  against  the  mercury  in 
the  cup  and  it  is  transmitted  thru  the  mer- 
cury to  the  open  end  of  the  tube.  Since 
the  tube  was  filled  with  mercury  and  there 
was  no  air  at  the  sealed  end,  we  get  the 
same  effect  as  if  air  was  there  originally 


School 

and  was  sucked  out;  i.e.,  there  is  no  air 
pressure  in  the  tube  and  the  air  pressure 
outside  can  hold  up  the  mercury  to  a  level 
of  about  thirty  inches.  If  now  the  seal 
is  broken  the  air  rushes  in  and  the  mer- 
cury in  the  tube  falls  into  the  cup.  (See 
Fig.  18-A.)  The  pressure  of  the  atmos- 
phere changes  from  place  to  place  and 
from  time  to  time.    It  is,  therefore,  im- 


Fig.  16 

*  Card 
/ 

Spool*  Yr^, 

.  / 

R  Pi 

If  You  Blow  Down  Thru  the  Spool  the  Card 
Sticks    to   the   Spool,    Contrary   to  General 
Opinion. 

portant  to  measure  the  exact  pressure  at 
each  locality.  It  is  possible  to  determine 
one's  height  above  sea  level  by  the  read- 
ing of  the  barometer.  Also  the  readings 
of  the  barometer  show  how  the  weather 
conditions  are.  The  barometer  is  nothing 
but  an  instrument  to  measure  the  pressure 
of  the  atmosphere.  Obviously  our  Fig. 
18-A  represents  a  crude  barometer.  Its 
great  disadvantage  is  that  when  carried 
about  from  place  to  place  one  is  likely  to 
spill  the  mercury.  An  improved  form  is 
shown  in  Fig.  18-B.  The  same  tube  used 
in  A  is  sealed  again,  bent  at  the  open  end 
and  filled  with  mercury.  The  air  pressure 
acting  at  the  open  end  supports  a  column 
in  the  closed  end,  so  th^t  th.  height  in  the 
closed  section  is  thirty  inches  above  the 
level  in  the  open  end.  In  the  commercial 
form  a  scale  (yard  stick)  -  attached  so 
that  one  can  read  the  levels  directly.  This 
form  can  be  carried  about  more  freely 
without  danger  of  spilling  the  mercury  but 
is  nevertheless  cumbersome  and  inconven- 
ient. The  aneroid  barometer  is  much  more 
compact  (it  can  be  had  even  as  small  as 
an  ordinary  alarm  clock).  Instead  of  mer- 
cury to  be  acted  upon,  this  instrument  em- 
ploys a  diafram  which  is  moved  in  and 
out  by  the  atmospheric  pressure  just  as  the 


A  Simple  Air  Thermometer — Utilizes  the  Ex- 
pansion of  Air  on  Heating  to  Vary  the  Height 
of  a  Water  Column. 

sheet  elastic  was  in  experiment  21.  The 
motion  of  the  diafram  is  magnified  by  a 
system  of  levers  and  is  communicated  to 
(Continued  on  page  -47) 


26 


THE  ELECTRICAL  EXPERIMENTER 


May,  1917 


Wireless  Telegraphy 


General  Superin 

THE  history  of  wireless  telegraphy 
repeats  once  more  the  old  story 
that  is  so  often  connected  with 
great  inventions.  The  world  be- 
ing possest  of  a  new  scientific 
principle,  many  minds  in  many  parts  of  the 
world  are  simultaneously  bent  upon  its 
practical  application,  with  the  result  that 
the  fundamental  principle  finds  embodi- 
ment in  various  methods  of  accomplishing 
a  similar  purpose.  The  startling  nature 
of  the  discovery  of  electric  waves  was 
bound  to  give  rise  to  unprecedented  activity 
in  the  field  of  experimental  investigation, 
and  such  experiments  as  were  particularly 
successful  were  bound  to  prompt  investi- 
gators to  seek  patent  protection  on  their 
modifications,  and  this  in  turn  gave  rise  to 
several  systems  of  radio-telegraphy. 

A  voluminous  list  of  names  could  be  giv- 
en of  those  who  have  contributed  to  the 
advancement  of  radio-telegraphy  in  regard 
to  both  theory  and  practise.  Among  the 
best-known  American  investigators  are  Fes- 
senden,  Shoemaker,  de  Forest,  Clark,  Stone 
and  Massie.  Each  of  these  men  f  as  devised 
a  system  which  bears  his  name.  In  Eng- 
land the  work  has  been  carried  on  by  men 


By  E.  B.  PILLSBURY 
tendent,  Marconi  Wireless  Telegraph  Company  of  America,  New  York 

of  such  unqualified  dis- 
tinction as  Lodge,  Alex- 
ander, Muirhead,  Flem- 
ing, Thomson  and  Ruth- 
erford. Slaby,  Arco  and 
Braun  are  the  names  best 
known  in  Germany.  The 
French  are  represented 
by  Ducretet,  Branly, 
Rochefort  and  Tissot,  be- 
sides other  men  of  lesser 
fame.  Italy  has  contrib- 
uted largely  to  the  sub- 
ject, principally  thru 
Marconi,  Bellini,  Tossi 
and  Righi.  Denmark  is 
represented  by  Poulsen. 
Spain,  Austria,  Bel- 
gium and  Argentina  have 
all  produced  systems 
which  have  been  more  or 
less  used  in  their  respect- 
ive countries.  The  Jap- 
anese have  also  devised  a 
system  that  successfully 
stood  the  test  of  service 
in  the  Russo-Japanese 
War. 


Interesting  View  of  a  Bank  of  High-speed,  Automatic  Sending 
Keys  and  Bus-bar  Connections  in  a  Typical  High-power  Marconi 
Radio  Station. 


Gigantic  Oscillation  Transformers  and  Tuning  Inductances  In 
Marconi  Trans-oceanic  Wireless  Transmitting  Station. 


The  development  of. 
the  art  in  the  various 
countries  has  been  car- 
ried on  largely  by  repre- 
sentative investigators, 
and  in  many  instances 
the  governments  have 
adopted  a  system  ex- 
ploited by  their  subjects. 
The  United  States  gov- 
ernment, however,  has 
experimented  with  most 
of  the  prominent  systems 
offered,  and,  as  a  result, 
the  army  and  navy  equip- 
ments are  comprised  of 
quite  a  variety  of  appa- 
ratus of  different  inven- 
tors. 

Wireless  telegraphy 
was  the  subject  of  ear- 
nest experimentation  as 


early  as  1838,  but,  as  far  as  the  public  mind 
is  concerned,  the  science  began  when  Mar- 
coni sent  his  first  message  across  the  At- 
lantic from  Cornwall  to  Newfoundland  in 
1902.  This  wonderful  accomplishment  had 
so  much  of  the  spectacular  element  in  it 
that  wireless  telegraphy  and  Marconi  be- 
came famous  at  once  and,  measured  by  re- 
sults, he  has  eclipsed  all  other  inventors. 

Marconi  first  interested  himself  in  the 
problem  of  wireless  telegraphy  in  1895.  In 
the  following  year  he  took  out  the  first  pat- 
ent ever  granted  in  England  for  a  practical 
system  of  wireless  telegraphy  by  the  use  of 
electric  waves.  In  1897  he  successfully 
communicated  across  Bristol  Channel,  a 
distance  of  nine  miles.  At  the  invitation  of 
the  Italian  government,  Mr.  'Marconi  sub- 
sequently went  to  Spezia,  where  his  system 
was  put  to  practical  test  on  board  two  It- 
alian battleships.    A  station  was  erected  on 

'International  Cable  Register  Supplement. 


May,  1917 


THE  ELECTRICAL  EXPERIMENTER 


27 


land,  and  the  ships  were  kept  in  constant 
telegraphic  communication  with  the  shore 
up  to  a  distance  of  twelve  miles.  Return- 
ing to  England  he  made  further  experi- 
ments and  succeeded  in  communicating  be- 


Looking  Up  One  of  the  Towering  450- Foot  Tub 
Masts,  Which  Support  the  Immense  Aerials  Used 
the  Ocean-wide  Signaling  Spans. 

tween  Salisbury  and  Bath,  a  distance  of 
thirty-four  miles. 

Mr.  Marconi  came  to  the  United  States 
in  1899,  in  connection  with  the  America 
yacht  cup  race  between  Columbia  and 
Shamrock  I,  In  the  same  year  a  number 
of  ships  of  the  British  navy  were  equipt 
with  his  apparatus.  Early  in  1901  tele- 
graphic communication  was  established  be- 
tween two  points  more  than  250  miles  dis- 
tant. In  February,  1902,  he  received,  on 
board  the  steamship  Philadelphia,  in  the 
presence  of  the  ship's  officers,  good  mes- 
sages on  a  recording  tape  when  at  a  dis- 
tance of  over  1,500  miles  from  the  trans- 
mitting station.  In  December,  1902,  he  es- 
tablisht  a  station  at  Cape  Breton  for  trans- 
atlantic service,  and  maintained  communi- 
cation with  the  Cornwall  station  at  Poldhu, 
transmitting  inaugural  messages  to  the 
King  of  England  and  the  King  of  Italy, 
the  London  Times  .  and  others.  A  year 
later,  during  the  voyage  of  the  steamer 
Lucania,  Mr.  Marconi  maintained  commu- 
nication between  the  ship  and  the  Marconi 
station  at  Glace  Bay,  in  Cape  Breton,  and 
Poldhu,  in  England,  and  a  newspaper  was 
publisht  and  issued  daily  to  each  passenger. 
A  powerful  station  at  Clifden,  on  the  west 
coast  of  Ireland,  was  opened  early  in  1907, 
by  means  of  which  public  communication 
across  the  Atlantic  was  establisht,  which 
has  been  maintained  ever  since. 

The  importance  of  wireless  equipment  of 


sea-going  vessels  has  been  recognized  by 
all  nations,  the  United  States  law  requiring 
two  licensed  operators  on  any  ship  carry- 
ing fifty  or  more  persons  and  sailing  be- 
tween ports  200  or  more  miles  apart.  It  is 
estimated  that  upward  of  5,000 
ships  are  now  equipt,  and  a 
large  number  of  freighters  car- 
ry wireless  for  their  own  pro- 
tection, altho  not  required  to 
do  so  by  law.  In  fifteen  years 
wireless  has  placed  to  its  cred- 
it the  saving  of  thousands  of 
lives  and  property  valued  at 
several  millions  of  dollars.  It 
is  an  inestimable  boon  to  man- 
kind that  we  can  go  to  sea  with 
the  knowledge  that  we  are  kept 
in  touch  with  home  and  can 
summon  aid  in  case  of  disaster 
by  means  of  the  S.  O.  S.  signal. 

Radio-telegraphy  is  a  most 
potent  factor  for  naval,  mili- 
tary and  airship  use  in  the  pres- 
ent war.  On  July  30,  1914, 
five  days  before  the  actual  dec- 
laration of  war,  the  English 
fleet,  which  had  just  left  Port- 
land, was  recalled  by  wire- 
less ;  and  on  August  4,  1914, 
Germany  flung  around  the 
world  on  its  chain  of  wireless 
stations  this  vital  message  to 
its  mercantile  marine :  "War 
declared  on  England ;  make  as 
quickly  as  you  can  for  neutral 
port."  This  first  dispatch  un- 
questionably saved  Germany 
many  millions  of  dollars  of 
property  and  secured  for  pos- 
sible future  use  a  fleet  of  pas- 
senger and  cargo  boats  which 
may  yet  play  a  great  part  in 
her  recovery  from  war's  rav- 
ages. 

As  long  distance  wireless 
rang  up  the  curtain  on  the 
greatest  war  the  world  has  yet 
witnessed,  so  it  has  continued 
to  play  a  great  part  therein. 
One  of  the  most  striking  points 
in  connection  with  wireless, 
which  has  been  developed  by 
the  war,  is  that  public  attention 
has  been  directed  upon  it  as 
never  before,  owing  to  the  fact 
that  so  much  of  the  official  communications, 
particularly  German  information,  has  been 
brought  to  the  notice  of  newspap_er  readers 
thru  this  medium,  owing  to  obstruction  of 
the  German  cables. 


ular  Steel 
to  Bridge 


One  of  the  objections  made  against  wire- 
less telegraphy  is  in  regard  to  the  possi- 
bility of  interference  between  various  sta- 
tions and  the  confusion  likely  to  arise  when 
a  number  of  stations  are  simultaneously 
operated  in  the  vicinity  of  one  another. 
Altho  this  confusion  does  rarely  arise  in 
practise  with  proper  up-to-date  stations  and 
apparatus,  yet  even  with  the  old  instruments 
when  it  did  occur  it  was  not  by  any  means 
such  a  serious  matter  as  generally  appeared 
to  the  imagination  of  the  public.  In  most 
countries  the  operation  of  wireless  tele- 
graph stations  in  regard  to  ship  and  shore 
communication  is  subject  to  judicious  rules 
tending  to  prevent  mutual  interference.  It 
is  well  known  that  without  proper  organi- 
zation and  discipline,,  serious  difficulties 
due  to  interference  would  occur  with  the 
great  majority  of  ordinary  land  wire  tele- 
graphs which  work  several  offices  by  means 
of  a  single  wire.  In  the  case  of  wireless 
telegraphy  it  is  often  an  advantage  that  any 
station  should  be  able  to  pick  up  a  mes- 
sage which  may  not  be  actually  addrest  to 
it,  as,  for  instance,  in  the  case  of  a  ship  in 
distress  calling  for  assistance.  The  most 
practical  method  of  isolating  any  particular 
receiver  so  as  to  make  it  sensitive  only  to 
signals  coming  from  a  certain  station  lies  in 
the  principles  of  resonance;  that  is,  to  tune 
the  sending  and  receiving  circuits  in  exact 
correspondence. 

When  the  war  broke  out  a  German  com- 
pany had  high-power  stations  in  commu- 
nication between  Sayville,  L.I.,  and  Nauen, 
Prussia  (3,262  miles),  and  between  Tuck- 
erton,  N.J.,  and  Eilvese,  Prussia  (3,383 
miles).  In  order  to  protect  our  neutrality 
the  American  government  took  over  these 
stations  and  is  now  operating  them  in  the 
interests  of  the  owners. 

The  government  has  erected  a  high-power 
station  at  Arlington,  within  sight  of  the 
Capitol  at  Washington,  with  a  radius  of 
3,000  miles  under  ordinary  conditions.  It 
represents  the  first  step  of  the  Navy  toward 
the  establishment  of  a  great  chain  of  high- 
power  wireless  stations  to  girdle  the  earth 
and  bring  the  Navy  Department  into  direct 
communication  with  the  fleet  thruout  the 
length  and  breadth  of  the  seas.  Unless  a 
war  vessel  be  in  the  Arctic,  Antarctic  or 
Indian  Oceans,  it  will  be  at  all  times  with- 
in the  range  of  one  of  the  seven  contempla- 
ted stations,  the  other  six  of  which  are  to 
be  located  at  San  Francisco,  Honolulu,  Ma- 
nila, Guam,  Panama  and  Samoa. 

From  the  Arlington  station  messages  can 
be  sent  to  vessels  stationed  beyond  the 
{Continued  on  page  77) 


500-horsepower  Steam  Turbines  and  Generators  in  Marconi  Trans-oceanic  Radio  Station. 


28 


THE  ELECTRICAL  EXPERIMENTER 


May,  1917 


San  Diego — Largest  Radio  Station  in  U.  S. 

By  J.  BASSETT 


THE  new  $300,000  wireless  telegraph 
station  at  San  Diego,  Calif.,  has  just 
been  completed  and  officially  put  in 
commission  January  26,  1917.  It  is  the 
largest  and  most  powerful  radio  station  in 
the  western  hemisphere.  It  is  capable  of 
flashing  messages  12,000  miles.  Messages 


three  100  kilowatt  transformers  2,800 
pounds  each. 

Establishment  of  a  distant  control  sys- 
tem will  enable  operators  at  any  naval  ra- 
dio station  on  the  Pacific  Coast  from  Point 
Loma  to  Alaska  to  operate  its  sending  in- 
struments. This  is  accom'plisht  by  a  sys- 
tem of  land  telegraph  lines.  The 
radio  apparatus  is  what  is  known 
as  the  Federal  Poulsen  arc  trans- 
mitter and  was  manufactured  by 
the  Federal  Telegraph  Co.,  of 
San  Francisco.  The  Poulsen  arc 
employs  a  direct  current  arc  of 
600  to  1,000  volts,  burning  in  a 
closed  chamber  of  hydrogen,  the 
terminals  being  placed  at  right 
angles   in   a   powerful  magnetic 


View  Above  Shows  Mission  Style  Operating 
Building  and  Fan-Tail  Lead-in  at  Powerful  New 

 U.  S.  Radio  Station,  San  Diego,  Cal.  

At  Right: — Looking  Up  One  of  the  Gigantic  600- 
Foot  Latticed  Steel  San  Diego  Wireless  Towers. 
Below: — Concrete   and    Porcelain    Base  Support 
for  Insulating  the  Steel  Tower  Legs. 


from  the  British  high  seas  fleet  cruising 
in  the  North  Sea,  from  the  high  powered 
German  plant  at  Berlin  and  from  Aus- 
tralia have  been  intercepted  thus  far. 

The  three  600  foot  aerial  towers  form 
a  triangle.  They  contain  one  million 
pounds  of  fabricated  steel  and  are  the 
largest  radio  towers  in  the  world.  The 
towers  are  triangular  in  section,  150  feet 
in  width  at  the  base  and  eight  feet  at  the 
apex.  They  are  placed  1,100  feet  apart. 
Porcelain  insulators  imbedded  in  concrete 
form  the  base  of  each  leg  of  the  towers. 

The  receiving  room  is  absolutely  sound 
proof,  the  walls  and  floor  being  padded 
with  asbestos.  There  are  four  distinct 
and  complete  controlling  sets  installed  in 
the  receiving  room,  enabling  any  one  of 
the  four  operators  or  all  four  at  once  to 
send  and  receive  messages. 

The  aerial  or  antennae  weigh  16  tons 
and  has  a  sag  between  towers  of  100  feet. 
The  aerial  is  twice  as  large  as  that  strung 
from  the  Eiffel  Tower  in  Paris.  The 
helix  is  14  feet  in  diameter  and  11  feet 
in  height  or  9  feet  higher  than  the  helix 
used  in  ordinary  naval  and  commercial 
stations. 

The  generator  weighs  60  tons  and  the 


field.  Electric  current  for  the 
radio  set  is  furnished  by  a  200 
kilowatt — 1,000  volt  direct  cur- 
rent generator,  driven  by  a  300 
horsepower  2,200  volt  60  cycle  in- 
duction motor. 

Six  buildings  costing  $39,590, 
in  mission  style  architecture, 
form  the  quarters  for  those  on 
duty.  Here  we  find  a  large,  airy 
dormitory,  gymnasium  and  well- 
furnished  library. 

A  silver  plated  telegraph  key  was  pre- 
sented to  Commander  Hooper  after  he  had 
dispatched  the  first  message.  The  fol- 
lowing inscription  was  on  the  key :  "High 
Power  Radio  Service,  First  Message, 
Com'd'r  S.  C.  Hooper,  Jan.  1917,  San  Die- 
go." At  exactly  11.02  January  26,  1917, 
Commander  Hooper  called  the  station  at 
Arlington  and  sent  this  message  from  the 
Mayor  of  San  Diego  to  Secretary  J. 
Daniels : 

"In  behalf  of  the  citizens  of  San  Diego 
I  have  the  honor  of  extending  to  you  the 
season's  greetings  and  their  good  wishes 
and  congratulate  you  upon  the  completion 
at  San  Diego  of  the  world's  most  power- 
ful radio  station.  Space  has  been  com- 
pletely annihilated  and  the  Atlantic  and 
Pacific  seaboards  are  as  one." 

Arlington  acknowledged  the  message  at 
11.05  o'clock.  It  was  immediately  trans- 
mitted by  telephone  to  Secretary  Daniels. 
His  reply  was  returned  at  11.18.  It  was 
thus : 

"Your  greetings  and  congratulations 
much  appreciated.  The  navy  department 
rejoices  with  San  Diego  that  the  comple- 
tion of  the  new  radio  station  at  San  Diego 


places  Washington  in  closer  touch  with 
the  Pacific  Coast  and  particularly  with  the 
navy's  larger  development  at  San  Diego. 
It  must  be  gratifying  to  California  to 
know  that  the  apparatus  installed  is  the 
product  of  a  California  company." 

This  was  followed  by  a  message  from 
Congressman  Kettner.  It  was  as  follows : 
"Washington  salutes  San  Diego,  first  port 
of  call  by  wireless.  Felicitations  extended 
thru  you  to  people  on  completion  of  the 
greatest  radio  station  in  the  United  States 
made  possible  by  your  esteemed  friends, 
Secretary  Daniels  and  Admiral  Griffin." 

It  was  answered  by  Howard  Veeder, 
vice-president  of  the  Federal  Telegraph 
Co.,  as  follows : 

"Please  accept    the  felicitation    of  the 
Federal  Telegraph  Co.  and  myself  person- 
ally upon  the  successful  opening  of  this 
great  radio  station.    It  is  a  g%eat  pleasure 
to  our  company  that  the  first  example  of 
this  most  remarkable  advance  in  the  ra- 
dio art,  which  has  been  developed  by  us 
in  San  Francisco  should  be  installed  in 
San  Diego,  a  sister  city." 

The  radio  plant  is  located  in  a  section 
called  Chollas  Heights,  ten  miles  from 
the  business  center  of  San  Diego,  on  an 
elevation  of  land,  reached  by  auto. 

U.S.  RADIO  INSPECTORS  USE 
CODE  MACHINE  IN  TESTING 
APPLICANTS. 

All  applicants  for  U.  S.  Government 
Radio   Operator's   License  must  pass  a 
test  in  receiving  messages  in  the  tele- 
graphic code,  i.e.,  in  the  form  of  dots  and 
dashes.     The  accompanying  illustration 
shows  a  new  complete  automatic  tele- 
graphic code  transmitter,  known  as  the 
Omnigraph,  complete  with  high-note  buz- 
zer and  exciting  batteries,  which  latter 
are  contained  in  the  base  of  the  cabinet. 
The  various   discs,  which  are  properly 
notched  on  their  periferies  to  correspond 
with  the  dots  and  dashes  of  the  different 
letters  of  the  alphabet,  are  placed  one 
above  the  other  on  a  rotatable  drum  or 
plate,  which  is  driven  by  a  strong  spring 
motor  provided  with  a  suitable  governor, 
in  order  that  the  discs  may  be  caused  to 
rotate  at  any  desired  speed. 

The  toothed  disc  makes  contact  with  a 
special  light  spring  brush  connected  with 
the  high-note  buzzer  circuit.  Thus,  as  the 
discs  slowly  rotate,  the  buzzer  circuit  is 
made  and  broken  in  accordance  with  the 
long  and  short  notches  on  the  edges  of  the 
discs. 

This  instrument  has  been  used  for  a 
number  of  years  by  the  government  officials 
in  examining  applicants  for  Radio  Opera- 
tor's License  and  has  been  found  very  sat- 
isfactory. The  messages  may  be  signaled 
with  this  apparatus  at  any  speed  from  12 


Automatic  Code  Apparatus  Used  by  U.  S. 
Radio    Inspectors   in    Examining  Applicants 
for  Operator's  License. 

words  up  to  30  words,  or  more,  per  min- 
ute, thus  giving  it  a  wide  range  of  useful- 
ness. 

A  large  variety  of  code  disc  are  available 
and  the  machine  may  be  set  up  to  give  dif- 
ferent code  combinations  as  often  as  de- 
sired. 


May,  1917 


THE  ELECTRICAL  EXPERIMENTER 


2<> 


WIRELESS  OUTFIT  ON  MOVING 
VAN  TRACES  MESSAGE. 

After  a  search  of  three  months  for  an  The  accompanying  photographs  show  the 
amateur  wireless  operator  who  sent  out  long  distance,  undamped  wave  receiving 
unsigned  "SOS"  messages  in  the  neighbor-  set  owned  by  Harvey  L.  Gamer,  Electrical 
hood  of  New  York  and  caused  great  an-  Engineer  of  Omaha,  Neb.,  with  which  the 
noyance  to  the  New  York  Navy 
Yard  and  navy  vessels  the  feder- 
al authorities  recently  arrested 
William  F.  Eckoff,  sixteen  years 
old,  who  had  a  wireless  station 
on  the  roof  of  his  home  in 
Brooklyn. 

When  the  messages  were  first 
heard  there  were  reports  in  ship- 
ping circles  of  submarines  operat- 
ing near  New  York.  After  sev- 
eral of  these  calls  stations  near- 
by recognized  them  as  the  work 
of  an  amateur.  The  New  York 
Herald's  wireless  station  worked 
■with  the  operators  at  the  New 
York  Navy  Yard  in  an  effort  to 
locate  the  station.  The  log  at  the 
Herald's  wireless  station  shows 
that  these  distress  messages  were 
sent  at  all  hours  of  the  night. 
The  mysterious  operator  used 
the  calls  of  the  Navy  Yard  and 
naval  vessels. 

Louis  R.  Krumm,  chief  radio 
inspector  of  the  Department  of 
Commerce,  engaged  a  moving 
van  and  installed  in  it  a  small 
wireless  set  which  could  detect 
messages  within  the  radius  of 
only  a  block.  Operators  had 
traced  the  messages  to  Brooklyn, 
and,  with  the  moving  van,  Mr. 
Krumm  went  about  Brooklyn  un- 
til he  arrived  in  front  of  the 
Court  Street  house. 

It  is  alleged  that  Eckoff  used 
a  United  States  code  signal  on 
the  night  of  January  twenty-first 
last,  sending  an  "SOS"  call  which 
which  was  picked  up  by  the  Herald  station 
and  relayed  to  t  e  super-dreadnought  Ari- 
zona at  the  New  York  yard. 

Eckoff  was  arraigned  before  United 
States  Commissioner  Louis  Bick  and  ad- 
mitted he  had  been  sending  messages,  but 
asserted  that  if  he  had  used  the  United 
States  code  he  had  done  it  innocently,  for 
he  did  not  understand  the  code  thoroly 
enough  to  commit  a  nuisance. 

The  efficiency  of  such  portable  radio  sta- 
tions has  been  markedly  improved  in  re- 
cent years  by  the  advent  of  spiral  aerials. 


An  Exceptional  Amateur  Radio  Station 


The  amplification  feature  is  obtained  by 
the  use  of  inductances  and  capacity  in  the 
wing  circuit  of  an  Audiotron,  then  a 
further   amplification   with   two  ordinary 


Above: — General  View  of  Ex- 
tremely Efficient  Experimental 
Radio  Station  Owned  by  Harvey 
L.  Gamer,  of  Omaha,  Neb.  Note 
Phonograph  at  Right  of  Photo; 
the  Signals   are    Recorded  on  it. 


Upper    Right    View    Shows  the 
Well     Designed     Antenna  Used 
With  the  Apparatus  Here  Illus- 
trated. 

Lower  Right: — Close  View  of 
15,000  Meter  Precision  Loose 
Coupler  and  Audion  Tuning  In- 
ductances. An  Engineer's  Idea  of 
How  an  Amateur  Station  Should 
be  Built. 


German  Stations  OUI, 
(Hanover),  POZ, 
(Nauen)  and  the  Hono- 
lulu Station  KHL,  are 
easily  heard. 

Some  of  the  stations  in  the  United 
States,  WSL  (Sayville),  and  especially 
WGG  (Tuckerton),  when  the  Goldschmit 
alternator  is  used,  come  in  so  loud  that 
the  signals  can  be  transmitted  over  the 
telephone  to  any  part  of  the  city  or  vicin- 
ity. Also  wax  phonograph  records  have 
been  made  with  a  special  recorder,  as 
shown  in  the  photograph. 


Audions  and  their  respective  coils  and  cir- 
cuits as  well  as  a  micro-phone  arrangement 
leading  to  the  recording  machine. 

The  large  loose  coupler  was  designed  to 
tune  to  wave  lengths  up  to  15,000  meters 
when  used  with  this  particular  aerial  sys- 
tem. 


SECRETARY  OF  COMMERCE 
SUSPENDS  ISSUING  OF  LICENSES 

Issuing  of  licenses  for  amateur  wireless 
apparatus  was  suspended  on  March  twenty- 
seventh  by  Secretary  Redfield.  Virtually 
none  of  the  amateurs  have  sending  equip- 
ment, so  the  military  and  naval  authorities 
have  not  considered  them  a  source  of  im- 
mediate danger,  but  Mr.  Redfield  decided 
that  no  more  should  be  licensed  for  the 
present.  Sending  wireless  plants  are  under 
the  strictest  possible  surveillance  now,  and 
if  a  state  of  war  is  declared  efforts  will  be 
made  to  locate  apparatus  of  every  descrip- 
tion. 

Many  of  the  amateurs  now  licensed  by 
the  Government  belong  to  the  Navy  radio 
reserve  and  will  be  called  upon  to  perform 
certain  duties  in  war. 


Uncle  Sam's  Radio  Inspectors  Find  it  Difficult  at  Times  to  Accurately  Locate  and  Run  Down 
Stations  which  Disobey  the  Law,  but  a  Radio  Set  and  Aerial  Erected  Inside  an  Auto  Van 

Helped  to  Solve  One  Problem. 


TO  TEACH  GIRLS  WIRELESS 

At  a  meeting  of  the  National  Special 
Aid  Society  recently,  a  school  offering  a 
course  in  wireless  telegraphy  for  young 
women  was  organized.  Instruction  will 
be  given  at  the  society's  headquarters,  259 
Fifth  Avenue,  New  York  Citv. 

Miss  Daisy  Florence,  chairman  of  the 
new  branch,  urges  that  all  young  women 
who  would  like  to  take  up  this  class  of 
work  send  in  their  applications.  E.  T. 
Bicak,  a  New  York  radio  expert,  has  been 
retained  and  will  have  entire  charge  of  the 
classes.  This  new  department,  the  society 
says,  is  the  first  of  the  kind. 


30 


THE  ELECTRICAL  EXPERIMENTER 


May,  1917 


How  the  Audion  Repeater  Repeats 

A  Twentieth  Century  Fairy  Tale,  Wherein  the  Mystery  of  the  Audion  Relay 
Is  Explained  for  the  Benefit  of  Radio  "Bugs"  of  All  Ages — From  9  to  90 


YOU  all  remember  what  you  learned 
at  school  about  matter  being  made 
up  of  molecules  and  molecules 
being  made  of  atoms  beyond  which 
matter  is  indivisible.  That  is, 
with  a  meat  axe,  you  can  divide  a  sub- 
stance into  small  pieces  like  hash ;  and  with 
a  microscope  and  hair-splitting  equipment 
you  can  divide  a  substanc  into  pieces 
smaller  than  the  naked  eye  can  distinguish ; 
after  that  by  means  of  chemicals  you  can 
separate  molecules  from  eac'  other  altho 
you  can't  see  them,  even  with  a  microscope ; 
then  with  more  chemicals  you  can  separate 
the  atoms  from  each  other,  but  beyond 
this  no  treatment  has  any  effect ;  at  least 
that's  what  we  learned  at  school  and  that 
effectually  proves  that  there  are  no  such 
things  as  fairies  or  daemons. 

But  now  come  our  highbrows  with  an- 
other story.  Mind  you,  you  don't  have  to 
believe  it.  They  say  that  atoms 
may  be  made  to  throw  off  par- 
ticles like  a  small  boy  throwing 
gravel  at  the  passing  trolley  car, 
only  the  kiddies  do  it  voluntar- 
ily for  the  fun  of  the  thing, 
whereas  the  atoms  must  have 
some  provocation ;  for  example, 
if  they  get  good  and  hot  they 
cqmmence  to  throw  gravel  like 
a,  terrier  pup  at  a  woodchuck 
hole. 

Now,  all  ordinary  people 
know  how  to  take  such  talk  as 
this.  It's  just  like  Arabian 
Nights  and  Dr.  Cook  stuff  about 
stones  talking  and  mountains 
splitting  open,  or  the  beautiful 
stripes  around  the  North  Pole. 
Nevertheless  one  of  our  cloister 
experts  will  draw  you  a  picture 
like  Fig.  1,  to  represent  the  in- 
terior of  a  vacuum  bulb  repeat- 
er, and  says  that  "F"  is  a  fila- 
ment, which  is  heated  red  hot 
by  the  electric  current  from  bat- 
tery "A,"  and  "P"  is  a  plate 
which  is  connected  to  the  out- 
going line.  In  the  space  be- 
tween the  filament  and  the  plate 
is  the  piece  of  picket  fence 
"G,"  which  is  connected  to  the 
incoming  line,  and  this  gridiron 
is  what  puts  the  fire  in  amplifier. 

To  make  the  matter  perfectly 
clear,  as  a  fairy  tale  should  be, 
look  at  Fig.  2,  where7  instead  of 
a  filament  there  is  an  iron  step- 
ladder  on  which  you  can  see  a 
lot   of   atoms,   or   daemons — it 
doesn't  matter  which  you  call 
them — and  on  the  other  side  you 
see  the  plate  as  in  Fig.  1.  Be- 
tween these  two  is  an  ordinary 
window  blind  with  slats  which 
are  all  operated  together  by  the 
usual  center  stick.   Now,  suppose 
a  strong  electric  current  is  past 
thru  the  iron  stepladder  so  that 
it  heats  up  like  the  filament  in 
Fig.  1,  then  each  little  daemon 
gets  as  mad  as  a  hen  on  a  hot 
griddle    and    begins    to  throw 
pebbles  at  the  window  shutter. 
What's  that !    Where  do  they  get  the  peb- 
bles?   Say,  this  is  a  fairy  story  and  you 
must    not    ask    foolish    questions.  Lord 
Kelvin  thought  the  atoms  were  made  of 
these    pebbles    or    corpuscles,    and  that 
these  pebbles  or  corpuscles  were,  in  fact, 
electricity  itself,  hence  the  name  electrons. 
In  other  words,  matter  is  made  of  electricity 
and  electricity  is  imponderable;  therefore, 
there  is  no  matter,  and  if  there  is  no  matter, 


it  doesn't  matter,  and  we  should  worry. 

If  while  the  daemons  are  bombarding 
the  shutter  we  should  open  the  slats, 
enough  pebbles  would  go  thru  and  strike 
the  plate  to  make  a  noise  like  a  hailstorm 
on  a  tin  roof  and  the  number  that  strike 
the  plate  would  be  in  proportion  to  the 
amount  the  slats  are  opened.  Therefore, 
if  the  slats  are  opened  and  closed  in  time 
with  music  it  would  be  possible  to  play  a 
tune  on  the  plate,  and  if  each  electron 
carried  a  little  bit  of  electricity  with  it, 
the  effect  would  be  like  a  current  from 
the  stepladder  to  the  plate,  and  this  cur- 
rent would  pulsate,  increasing  when  the 
slats  are  opened  and  decreasing  when  they 
are  closed. 

This  is  just  what  happens  in  the  vacuum 
repeater  bulb  shown  in  Fig.  1.  The  filament 
is  heated  red  hot  by  the  current  from 
battery  "A,"  and"  at  this  temperature  mil- 


The  Above  Illustrations  Help  to  Make  Clear  in  the  Most  Simple 
Manner,  the  Action  of  the  Audion — That  Mysterious  Radio-elec- 
trical Device.  Considering  the  Top  View,  Just  Imagine  That  the 
Host  of  Daemons  on  the  Ladder  (the  Filament)  Start  Throwing 
Pebbles  Thru  the  Movable  Slats  (the  Grid)  at  the  Target  (the 
Plate).  How  Do  They  Get  the  Pebbles? — Oh!  Well — Read  This 
Remarkable  Tale. 

lions  of  corpuscles  or  electrons  are  thrown 
off.  The  electric  current  is  not  necessary 
to  cause  this ;  the  same  thing  would  hap- 
pen if  it  were  heated  by  a  gas  flame. 
These  electrons  are  considered  to  carry 
charges  of  negative  electricity  itself.  Here 
again  we  should  worry,  because  the  result 
is  the  same,  no  matter  what  anyone  thinks ; 
because  a  current  actually  does  flow  from 
the  filament  to  the  plate. 


You  all  remember  that  unlike  polarities 
of  electricity  attract  each  other  while  like 
polarities  repel,  and  so  if  the  gridiron  is 
made  negative  to  the  filament  the  electrons 
will  be  repelled  by  it  and  very  few  will 
get  thru  between  the  slats;  in  fact,  if  the 
slats  are  too  close  together  no  electrons 
at  all  will  get  thru  to  the  plate.  The  ef- 
fect would  be  the  same  as  tho  the  slats  in 
Fig.  2  were  entirely  closed. 

It  is  generally  known  how  the  sound 
waves  produce  electrical  pulsations  in  a 
telephone  line;  and  you  have  only  to  im- 
agine these  pulsations  of  current  coming 
to  the  induction  coil  "T"  at  the  left  side 
of  Fig.  1.  These  pulsations  are,  of  course, 
very  weak  because  of  the  long  line  over 
which  they  have  traveled  and  the  purpose 
of  the  repeater  is  to  amplify  or  strengthen 
these  pulsations. 

Now,  while  it  takes  considerable  power 
to  open  and  close  the  slats  of 
a  window  blind,  especially  if 
you  painted  them  yourself  last 
spring,  the  operation  of  the 
electric  shutter  is  frictionless 
and  even  the  weak  impulses  of 
speech  transmitted  over  500 
miles  of  line  are  sufficient  to 
give  the  desired  results  so  that 
as  each  increase  or  decrease  of 
current  raises  or  lowers  the 
negative  potential  of  the  grat- 
ing "G,"  more  or  less  electrons 
each  with  its  infinitesimal 
charge  of  electricity  get  thru 
from  the  red-hot  filament  to  the 
plate  and  give  the  exact  same, 
but  much  stronger,  impulses  of 
current  from  the  plate  to  the 
induction  coil  at  the  right  side 
of  the  picture,  and  so  out  on 
the  line  for  another  500  miles, 
the  amount  ■  of  additional  pep 
put  in  the  impulses,  depending 
on  the  strength  of  the  battery 
"B." 

Now  you  are  probably  won- 
dering why  this  apparatus  is  put 
in  a  glass  case.  The  reason  is 
that  the  scheme  will  only  work 
in  a  very  good  vacuum  because 
a  clear  space  is  necessary  for 
the  electrons  to  travel  in.  You 
must  remember  that  everything, 
even  an  invisible  gas,  is  com- 
posed of  atoms,  so  if  there  was 
air  or  any  kind  of  gas  in  the 
space  between  the  filament  and 
the  plate,  the  electrons  would 
bump  the  atoms  of  the  gas 
while  the  daemons  might  put  a 
good  many  across,  the  number 
would  not  be  constant  from 
minute  to  minute,  depending  on 
how  successful  they  were  in 
dodging  the  atoms  and  the  re- 
sult of  this  would  be  a  jerky 
current  which  would  entirely 
mask  the  telephonic  pulsations. 
Therefore,  in  order  to  obtain 
the  required  accuracy  of  con- 
trol of  the  rate  at  which  the 
electrons  strike  the  piate,  it  is 
necessary  to  pull  out  of  the 
space  between  the  filament  and  the  plate 
every  loose  atom  that  it  is  physically  pos- 
sible to  get  hold  of.  , 

This  is  so  important  that  our  highbrows 
have  developed  an  extremely  interesting 
method  of  inducing  daemons  themselves  to 
call  the  game  when  the  space  is  cleared, 
but  that  is  another  story  to  be  told  when 
you  have  recovered  from  this  one. — 
'"W.E.N." 


May,  1917  THE  ELECTRICAL  EXPERIMENTER  3 

The  Ionic  Radio  System  and  Theory  of  Ionic  Tuning 

By  Otto  E.  Curtis 

Associate  Member  ot  the  Institute  of  Radio  Engineers 


THE  physico-chemical  science  per- 
taining to  the  elemental  constitu- 
tion of  matter  and  the  relation  of 
the  ion  to   the   organization  of 
matter  dates  back  to  the  time  of 
Thales  of   the  so-called   "early   school  of 
Ionic  Philosophers,"  which  came  into  exis- 
tence about  six  centuries  ii'.C.    Thales,  and 


The   Apparatus    Used    in    Ionic   Tuning  of 
Radio  Messages  According  to  the  Method  of 
Mr.  Curtis,  as  Described  Herein. 

the  other  scholars  of  this  time,  made  little 
real  progress  toward  a  scientific  develop- 
ment of  the  subject,  altho  in  the  light  of 
recent  discoveries  many  of  their  heretofore 
seemingly  crude  experiments  and  theories 
'appear  to  have  surprising  significance. 

For  example,  the  ancient  Alchemists  of 
this  period  made  many  attempts  at  "trans- 
mutation," that  is,  at  converting  basic  met- 
als such  as  lead  into  precious  metals  such 
as  gold,  and  in  connection  with  these  ex- 
periments they  developed  theories  which, 
while  entirely  too  vague  to  lead  to  useful 
conclusions,  bear  similarities  to  the  modern 
theories  pertaining  to  tne  transmutation  or 
transformation  of  various  radio-active  com- 
positions of  matter  into  other  comoounds 
having  different  ionic  groupings.  Howev- 
er, the  secrets  pertaining  to  the  part  played 
by  ions  in  the  constitution  of  matter  have 
not,  at  least  up  to  the  present  time,  been 
discovered  and  subjected  to  the  use  of  man. 

During  the  past  eleven  years  I  have  been 
continually  striving  to  fathom  some  of  these 
secrets  and  it  is  my  present  purpose  to  dis- 
close one  of  the  more  important  discoveries 
which  has  resulted  from  my  investigations, 
this  particular  discovery  forming  the  ba- 
sis of  one  of  my  earlier  patent  applications. 
And  in  order  more  clearly  to  set  forth  this 
discovery  I  ^hall  first  describe  some  of  my 
experiments  and  the  apparatus  employed. 

The  first  machine  I  built  with  the  object 
of  recording  messages  was  completed  in 
1906.  It  consisted  of  an  E.  I.  Co.  "Auto- 
coherer"  connected  to  a  "Telimco-meter" 
galvanometer  with  contacts  on  the  needle. 
Impulses  received  by  the  auto-coherer  were 
intended  to  deflect  the  needle  and  close 
relay  contacts,  but  they  did  not  do  so  and 
this  machine  failed  to  operate.  This  was 
an  attempt  to  find  a  self-restoring  coherer, 
but,  while  the  coherer  was  self-restoring, 
it  was  not  sufficiently  responsive  to  current 
of  the  magnitude  which  I  then  employed. 

A  later  machine,  completed  November 
25,  1916,  and  shown  in  the  accompanying 
photograph,  follows  the  same  original  idea 
but  its  special  parts  have  been  much  more 
highly  developed.  It  receives  perfectly  the 
time  from  Arlington  at  a  distance  of  200 
miles,  ticking  it  off  clearly  on  a  buzzer  and 
making  tape  records  of  the  same,  but  as  yet 

*  Copyright  1917  by  Roberts,  Roberts  and  Cush- 
man.  Exclusive  rights  to  The  Electrical  Experi- 
menter. 


it  is  not  quite  fast  enough  to  copy  actual 
commercial  messages.  It  was  originally  de- 
signed as  a  chemically  tuned  call-bell  for  a 
wireless  telephone,  for  which  it  works  ex- 
cellently. (This  process  of  chemical  tun- 
ing or  Ionic  tuning  will  be  explained  fur- 
ther on.) 

The  apparatus  illustrated  in  the  photo- 
graph is  made  up  as  follows :  The  device 
shown  in  the  upper  left-hand  corner  is  a 
Multi-audi-fone  pocket  wireless  set.  The 
wooden  base  in  the  lower  left-hand  corner 
carries  two  of  my  ionic  detectors  construct- 
ed as  shown  in  Fig.  5,  and  as  hereinafter 
described,  the  one  on  the  left  comprising  a 
zincite  crystal  and  the  one  on  the  right  a 
silicon  crystal.  The  rectangular  instrument 
in  the  center  is  a  Weston  relay,  which  com- 
prises an  extremely  sensitive  galvanometer 
having  a  very  short  needle  which,  when  de- 
flected, contacts  with  one  of  the  platinum- 
iridium  points  disposed  on  opposite  sides  of 
the  needle.  The  instrument  on  the  right  is 
an  E.  I.  Co.  polarized  relay  of  1,000  ohms 
resistance  which  may  be  connected  to  an 
indicating  or  recording  or  other  device  such 
as  a  buzzer,  tape  recorder,  motor,  lamp  or 
explosive  device. 

In  the  accompanying  figures,  Fig.  1  shows 
the  circuit  connections  for  the  apparatus 
shown  in  the  photograph,  the  various  instru- 
ments being  diagrammatically  illustrated  in 
the  figure  in  the  same  relative  positions  as 
in  the  photograph  for  the  sake  of  clear- 
ness. The  antenna  1  is  connected  to  ground 
2  thru  the  primary  3  of  the  Multi-audi- 
fone  set,  the  secondary  4,  of  which  is  ar- 
ranged to  be  connected  to  the  Weston  re- 
lay by  means  of  double  throw  switch  5 
either  thru  detector  10  or  thru  detectors 
7  and  8.    When  the  switch  9  is  to  the  left, 


Diagram  of  Connections 
Possible   to   Realize  the 
Claimed.  Besides, 

the  zincite  detector  7  is  connected  in  cir- 
cuit; when  the  switch  9  is  to  the  right  the 
silicon  detector  8  is  in  circuit,  the  detectors 


7  and  8  being  connected  to  the  secondary 

4  by  leads  which  arc  not  shown.  The  cir- 
cuit connections  as  existing  when  the  switch 

5  is  in  upper  position,  are  shown  in  simpli- 
fied form  in  Fig.  2,  reference  to  which  may 
be  had  in  following  out  the  operation. 

The  alternating  current  of  radio  fre- 
quency received  by  the  open  antenna  circuit 
1-3-2  is  induced  into  the  secondary  circuuit, 
where  it  is  rectified  by  the  detector  10  and 
conducted  to  the  Weston  relay  6.  This  pro- 
duces a  deflection  of  the  relay  6  which  in 
turn  closes  the  local  circuit  containing  the 
polarized  relay  11  and  source  of  e.m.f.  12. 
This  actuates  relay  11,  which  closes  the 
circuit  thru  a  second  source  of  e.m.f.  13  and 
the  indicating,  recording  or  power  appa- 
ratus 14.  By  employing  one  of  my  im- 
proved ionic  detectors  at  10,  very  feeble  im- 
pulses may  be  detected ;  and  by  employing 
a  series  of  relays  in  the  manner  described, 
the  feeble  impulses  may  be  magnified  to  any 
desired  extent,  each  consecutive  relay  con- 
trolling a  heavier  current  so  that  the  last 
circuit  11-13-14  may  comprise  a  power  cir- 
cuit carrying  current  of  any  strength. 

When  using  the  machine  for  lecture  pur- 
poses, with  the  sender  in  the  same  room 
a  "Hertz"  lineal  resonator  is  used  instead 
of  an  aerial  and  ground,  as  shown  in  Fig. 
3.  This  consists  of  two  lA  inch  brass  rods 
fitted  on  adjacent  ends  with  brass  balls  of 
equal  size  and  separated  a  short  distance, 
this  distance  bearing  a  direct  ratio  to  the 
length  of  the  spark  gap  of  the  sender.  The 
free  ends  of  the  rods  are  fitted  with  the 
movable  metallic  plates  15.  Moving  these 
plates  together  with  the  similar  ones  on  the 
oscillator  of  the  spark  gap  tunes  the  sys- 
tem.   This  "resonator"  serves  the  same  pur- 


pose as  the  "catch  wires"  used  on  the  E.  I. 
Co.  "Telimco  Coherer  Set."    The  resonator, 
(Continued  on  page  73) 


Used  in  the  Curtis  Scheme  of  Ionic  Tuning,  Whereby  It  Becomes 
Highest  Efficiency  in  Radio  Transmission  and  Reception,  It  Is 
It  Enables  the  Operator  to  Record  the  Messages  if  Desired. 


32  THE  ELECTRICAL  EXPERIMENTER  May,  1917 

Receiving  Marconi  300  K.W.  Spark  Stations  with  Oscillating  Audion 

By  SAMUEL  CURTIS,  Jr. 


IT  is  a  widely  known  fact  that  the 
Marconi  Wireless  Telegraph  Com- 
pany has  in  operation  a  number  of  300 
K.W.  spark  stations,  used  for  the 
purpose  of  handling  their  enormous 
traffic  between  different  countries.  The 
stations  of  this  character  which  are  active- 
ly engaged,  to  my  knowledge,  in  transact- 
ing business  at  the  present  time,  are :  Clif- 
den,  Ireland;  Glace  Bay,  Nova  Scotia;  Bo- 
linas,  California ;  Koko  Head,  Hawaii,  and 
Funabashi,  Japan. 

The  wave  length  used  in  transmission 
ranges  from  4,000  to  8,000  meters,  but 
the  most  common  is  6,100;  this  is  used  ex- 
tensively at  the  Koko  Head  and  Bolinas 
stations. 

In  receiving  the  signals  from  these  sta- 
tions, any  Audion  receiver  capable  of  at- 
taining the  wave  length  may  be  used,  and 
it  may  be  well  to  state  that  the  undamped 
wave  receiver  described  on  page  575  of  the 
December  issue  of  The  Electrical  Ex- 
perimenter has  been  used  in  this  respect 
with  marked  success.  The  writer  wishes 
to  state,  however,  that  since  the  publica- 
tion of  his  article  relative  to  this  receiving 
set,  a  fixt  condenser  of  .005  m.f.  has  been 
added  to  the  circuit.  This  is  hooked  up 
across  the  telephones  and  high  potential 
battery  of  the  Audion,  and  by  its  use  al- 
lows the  bulb  filament  to  be  burned  at 
a  much  lower  brilliancy,  and  yet  get  strong 
oscillations  therefrom. 

It  is,  of  course,  easily  possible  to  receive 
these  stations  on  a  crystal  detector,  but  un- 
less an  extremely  large  antenna  is  avail- 
able, .this  cannot  be  accomplished  over  any 
great  distance.  It  has  been  found  by  ex- 
periment that  a  heterodynic  action  on  the 
incoming  signals  produces  a  remarkable 
increase  in  audibility,  therefore  making  it 
feasible  to  incorporate  the  use  of  an  os- 
cillating Audion  in  this  respect. 

The  series  of  graphs  shown  in  Fig.  1 
clearly  illustrate  the  character  of  the  mo- 
mentary currents  produced  by  a  feebly 
damped  wave  train,  in  the  circuits  of  a 
receiver  during  the  process  of  heterodyn- 
ing.    In  graph  "A"  we  have  the  feebly 


The  Series  of  Graphs  Shown  Above  Serve  to 
Illustrate  the  Character  of  the  Momentary 
Currents  Produced  by  a  Feebly  Damped 
Wave  Train,  in  the  Circuits  of  a  Radio 
Receiver  During  the  Process  of  "Heterodyn- 
ing." 

damped  wave  train,  such  as  is  sent  out  by 
the  above  mentioned  high-powered  stations. 
In  graph  "B"  we  have  the  local  or  Audion 
oscillations,  which  are  used  in  heterodyn- 
ing the  wave  train  of  graph  "A."  These 


Audion  oscillations  are  tuned  to  a  fre- 
quency either  higher  or  lower  than  that  of 
the  incoming  wave,  so  that  an  audible  note 
is  obtained  in  the  telephones.  In  graph  "C" 
we  have  an  illustration  of  the  current  pro- 
duced after  "A"  and  "B"  have  coincided 
with,  or  heterodyned  each  other.  In  graph 
'D"  is  shown  the  resultant  current  after 
it  has  been  rectified.  It  should  be  under- 
stood that  the  tone  of  this  current  in  the 
telephones  is  proportionate  to  the  difference 
in  frequency  of  the  incoming  wave,  and  the 
Audion  oscillations;  for  instance,  a  wave 
length  of  6,000  meters  would  have  a  fre- 
quency of  50,000  cycles.  In  order  to  get 
an  audible  note  of  500  cycle  pitch,  we 
would  have  to  have  an  Audion  frequency 
or  either  49,500  or  50,500  cycles.  This  is 
assuming  that  we  are  heterodyning  an  un- 
damped wave.  Of  course  when  a  damped 
wave  is  heterodyned  it  cannot  be  expected 
that  a  pure  note  will  be  obtained,  owing  to 
its  irregular  form.  In  actual  practise  the 
note  obtained  in  heterodyning  the  Mar- 
coni signals  is  very  near  the  same  as  that 
obtained  by  using  a  crystal,  only  a  little 
distorted. 

The  beauty  of  the  use  of  the  heterodyne 
reveals  itself  in  an  astonishing  increase 
in  the  amplitude  of  the  telephonic  current, 
as  illustrated  in  sketch  No.  2.  It  can  be 
seen  by  observation  of  this  sketch  that  the 
mere  rectification  of  a  wave  train  does  not 
in  any  way  amplify  it.  Now,  .if  the  same 
wave  train  is  heterodyned,  an  increase 
in  amplitude  similar  to  that  illustrated  in 
sketch  No.  2  is  obtained.  The  reason  for 
this  is  best  explained  by  the  fact  that  in 
the  mere  rectification  of  a  damped  wave 
train,  only  the  first  few  oscillations  are 
utilized,  and  the  rest  of  the  energy  is  hope- 
lessly wasted.  In  subjecting  a  feebly  dampt 
wave  train  to  heterodynic  action  practi- 
cally all  of  the  energy  is  utilized,  mani- 
festing itself  in  an  enormous  increase  of 
audibility.  To  those  who  are  more  or  less 
familiar  with  the  action  of  the  heterodyne, 
this  brief  explanation  will  suffice,  but  to  go 
into  a  detailed  description  thereof  would  be 
out  of  the  scope  of  this  article. 

It  might  be  of  interest  for  the  reader 
to  know  that  at  the  present  time,  at  a  cer- 
tain experimental  station  on  the  Atlantic 
Coast,  signals  are  being  received  daily 
from  the  Marconi  station  at  Koko  Head, 
Hawaii.  The  receiver  used  is  of  the  type 
described  in  the  December  issue  of  this 
journal  with  the  single  exception  that  an 
Electron  Relay  is  used  instead  of  the  usual 
spheric  Audion  bulb  for  producing  the  os- 
cillations. Glace  Bay,  Nova  Scotia,  comes 
in  with  remarkable  audibility,  while  Boli- 
nas, California,  is  read  nearly  as  loud.  The 
stations  at  Clifden,  Ireland,  and  Funabashi, 
Japan,  have  not  as  yet  been  pickt  up,  but  it 
is  expected  that  in  the  near  future  Clifden 
will  be  copied,  as  this  station  is  not  nearly 
as  far  distant  as  Koko  Head,  who  is  read 
in  the  daytime  in  good  weather.  The 
aerial  used  at  the  above  mentioned  sta- 
tion has  a  natural  period  of  276  meters, 
and  is  none  too  elaborate. 

The  results  made  possible  by  the  oscil- 
lating Audion  in  receiving  dampt  waves  are 
not  however  confined  to  such  long  waves 
as  are  used  by  the  Marconi  stations.  With 
careful  adjustments  and  the  use  of  low 
resistanced  inductances,  an  Audion  can 
be  made  to  oscillate  on  200  meters  or  less, 
depending  of  course  upon  the  skill  and 
perseverance  of  the  operator. 

No  one  can  fully  appreciate  the  efficiency 
of  such  a  method  of  reception  until  he  has 
actually  used  it  himself.  At  the  present 
time  there  are  a  number  of  Regenerative 
receivers  on  the   market.     These  instru- 


ments are  without  a  doubt  the  peer  of  any- 
thing in  their  line,  but  for  many  experi- 
menters the  price  of  such  an  outfit  is  pro- 
hibitively high,  and  the  chances  are  they 
have  to  do  without.  One  advantage,  how- 
ever, is  that  these  receivers  are  not  so  in- 
tricately designed  as  to  make  it  impossible 


1 

\ 

Fig.  2 


Graph   Illustrating  the   Marked   Increase  in 
the   Amplitude  of   Received    Radio  Signals 
Due  to   "Heterodyning"   by    Means  of  the 
Oscillating  Audion. 

for  the  experimenter  to  make  one  for  him- 
self. This  is  being  done  with  great  suc- 
cess by  a  large  number  of  amateurs  thru- 
out  the  country.  If  the  reader  cares  to 
take  the  trouble  to  consult  page  575  of  the 
December  issue  of  this  magazine,  he  will 
see  a  neat  little  regenerative  hook-up 
given  in  set  "B"  of  the  diagram  on  that 
page.  Set  "A"  is  used  for  long  waves, 
and  set  "B"  for  waves  from  200  to  2,500 
meters. 

[We  are  informed  by  Mr.  Curtis  that  in 
some  tests  conducted  in  the  laboratories 
of  the  General  Electric  Co.,  at  Schenecta- 
dy, Dr.  White  has  succeeded  in  making  an 
Audion  oscillate  (heterodyne  action)  on  a 
wave  length  as  low  as  y2  meter.  Of  course 
this  requires  some  elaborate  tuning  and 
even  more  elaborate  apparatus.— Ed.] 


RADIO  EXHIBIT  AT  NEW  YORK 
AERO  SHOW. 

At  the  recent  Aeronautical  Exposition 
held  in  New  York  City,  serious  considera- 
tion was  .given  to  radio  equipments  for 
aeroplanes  and  balloons.  A  large  space 
was  set  aside  for  the  exhibition  of  different 
types  of  sets,  such  as  are  used  now  in  the 
European  countries  for  directing  the  artil- 
lery from  aeroplanes,  for  interfering  with 
stations  and  for  long  distance  communica- 
tion to  be  used  by  observers.  Models  of 
the  different  types  of  wireless  equipments 
using  direct  and  alternating  current  gener- 
ated by  small  dynamos  which  get  their 
power  from  the  air  by  means  of  a  small 
propeller  were  shown.  The  Marconi  Com- 
pany was  invited  to  exhibit  the  set  which 
was  recently  purchased  by  the  Navy  De- 
partment for  hydroaeroplanes.  This  in- 
strument has  one  K.W.  capacity  and  it  is 
stated  that  up  to  300  miles  will  be  obtained. 
That  is  to  say,  the  aeroplane  can  signal  for 
a  radius  of  300  miles.  The  total  installa- 
tion will  come  within  100  pounds.  Other 
sets  made  by  the  Sperry  Gyroscope  Com- 
pany, De  Forest  Radio  Telephone  &  Tele- 
graph Company;  William  Dubilier,  Wire- 
less Specialty  Apparatus  Company,  Cutting 
&  Washington,  Manhattan  Electric  Supply 
Company  and  Mr.  A.  B.  Cole.  The  wire- 
less operators  were  supplied  by  the  East 
Side  Y.M.C.A.  under  the  direction  of  Mr. 
Boehm. 


May,  1917 


THE  ELECTRICAL  EXPERIMENTER 


33 


Distributed  Capacity  and  Its  Effect 


D 


capacity 


ISTRIBUTED  capacity  may  be 
defined  as  the  capacity  existing 
between  turns  of  a  helical  coil. 
It  may  also  exist  in  straight  con- 
ductors where  the  electrostatic 
s  between  the  conductor  and  the 


Theoretical  Relation  of  Distributed  Capacity 
to  Inductance  Coils.    The  Effect  Is  the  Same 
As  if  a  Number  of  Small  Condensers  Were 
Connected  Across  the  Turns  on  the  Coil. 

earth,  or  between  two  adjacent  conductors. 

It  can  be  shown  by  actual  experiment 
that  a  difference  of  potential  exists  be- 
tween adjacent  turns.  This  potential  dif- 
ference creates  an  electrostatic  field  and 
energy  is  stored  between  the  conductors. 

A  condenser  is  a  device  which  stores 
electrostatic  capacity.  It  is  evident  there- 
fore that  a  condenser  is  formed,  the  plates 
of  which  are  the  adjacent  conductor  turns. 
The  capacity  is  stored  in  the  space  between 
each  turn  of  the  coil  and  over  all  of  the 
turns,  therefore  the  capacity  is  distributed 
over  the  entire  conductor. 

Referring  to  Fig.  1,  it  will  be  seen  how 
distributed  capacity  is  related  to  coils.  In- 
creasing the  length  of  the  coil,  increases  the 
distributed  capacity  as  it  is  seen  that  the 
number  of  condensers  are  increased.  Since 
increasing  the  number  of  condensers  in 
parallel  increased  the  capacity,  therefore 
we  may  consider  all  the  parallel  condensers 
as  one  large  capacity  shunted  across  the 
inductance,  as  indicated  in  Fig.  2. 

When  capacity  and  inductance  are  linked, 
in  a  circuit  we  have  an  oscillatory  circuit, 
and  the  period  of  vibration  of  such  a  sys- 
tem is  directly  proportional  to  the  square 
root  of  the  product  of  the  inductance  and 
capacity  multiplied  by  a  constant  Ex- 
pressing the  above  in  an  algebraic  form 
we  have: 

n  = ,    4     ■  (l) 

Here  n  =  period  of  vibration  of  the  sys- 
tem. The  wave  length  of  the  above  cur- 
rent is, 

A  =  59.6V£~c  W 


Representing    the    Relation    of  Distributed 
Capacity  in  a  Coil  (Fig.  2)  and  the  Voltage 
and  Current  Distribution  in  Inductance  Coils 
(Fig.  3). 

where  L  and  C  are  the  inductance  and  ca- 
pacity. 

It  is  evident  therefore  that  since  the  coil 


By  SAMUEL  COHEN 

has  distributed  capacity  that  the  coil  is  an 
oscillatory  circuit  in  itself,  and  it  was  found 
by  actual  experiment  that  when  properly 
excited  by  a  high  frequency  current,  it  will 
oscillate,  the  period  of  which  depends  upon 
the  magnitude  of  the  units  of  inductance 
and  capacity. 

The  true  wave  length  of  a  circuit  con- 
taining a  large  inductance  and  shunted  with 
a  capacity  is  not  the  same  when  calculated 
with  formula  (2)  but  the  exact  wave 
lengths  will  be  as  exprest  in  the  follow- 
ing relation  : 

a  =  59.6  -s/L(C  +CX)  <3> 

Where  C  is  the  capacity  of  the  shunted 
condenser  and  to  it  we  add  the  distributed 
capacity  of  the  coil  Cx.  Solving  for  Cx 
we  have : 

C«=  A~LC'  (4) 

Calling  the  total  capacity  Ct  equation  (4) 
becomes : 

Cl=(59^Z  (5)31 

It  has  also  been  found  by  actual  experi- 
ment that  whenever  a  large  coil  was  ex- 
cited by  radio  frequency  current  it  will 


Primary,  str/fc/)  ' 

KSmk/)  0.0  ooint 
--J^^S^w^  off 'point  r> 


Fig.   5.     Dead-end    Elimination    Switch  for 
Loose    Couplers    Which    Has    Proven  Very 
Effective   in   Reducing   Distributed  Capacity 
in  the  Windings. 


oscillate  in  its  own  period  just  the  same 
as  a  coil  shunted  with  a  condenser  and 
excited.  The  current  and  voltage  relation 
of  this  coil  is  exactly  the  same  as  for  a 
Hertz  oscillator,  where  the  current  value 
is  a  maximum  at  its  center  and  minimum 
at  the  ends,  while  the  voltage  is  maximum 
at  the  ends  and  minimum  at  the  center. 
Fig.  3  shows  grafically  this  relation  of  the 
coil. 

The  best  means  for  determining  the  dis- 
tributed capacity  is  by  actual  measurement. 
The  essential  instruments  necessary  for  this 
kind  of  work  are  calibrated  inductance  and 
capacity  which  may  be  obtained  from  a 
wave  meter,  a  high  frequency  buzzer  and 
an  additional  condenser.  The  instruments 
are  connected  as  indicated  in  Fig.  4.  The 
coil,  whose  distributed  capacity  is  to  be  de- 
termined, is  placed  in  a  single  loop  of  wire 
L,  Fig.  4,  which  is  excited  by  the  buzzer, 
Placing  the  wave  meter  inductance  L2  near 
the  excited  circuit  the  condenser  C2  is 
turned  for  indicating  resonance.  When  the 
point  of  resonance  is  obtained  the  period 
of  vibration  of  both  circuits  are  the  same 


T  =  T.  Substituting  the  observed  values 
in  the  equation, 


Cd  = 


(5) 


Arrangement  of  Apparatus  for  Measuring 
the  Distributed  Capacity  in  a  Coil.  A  Buzzer 
Serves  for  Excitation  of  the  Coil  Under 
Measurement,  While  a  Wave  Meter  Is  Used 
to  Ascertain  the  Wave  Length  of  the  Coil. 

Where  L2  =  the  inductance  of  wave  meter 
coil  in  centimeters. 
C2  =  capacity  of  condenser  at  point 

of  resonance  in  m.f. 
Li  =  inductance  of  coil,  the  distri- 
buted capacity  of  which 
to  be  found. 
It  is  advisable  before  starting  to  meas- 
ure the  distributed  capacity  of  a  coil,  to 
determine  before-hand  the  magnitude  of 
the  figures  so  as  to  enable  us  to  procure 
approximately  the  proper  inductances  and 
capacity  in  the  wave  meter  circuit.    It  can 
either  be  found  by  judging  it  from  expe- 
rience or  else  by  actually  calculating  its 
value.    An  approximate  formula  has  been 
derived  by  Drude  for  the  calculation  of  the, 
distributed  capacity  as  follows : 

Cd=2K  T-  5—  (6) 


10+4 


+  3- 


Where  "h"  and  "r"  are  the  length  and 
radius  of  the  coil  respectively.    The  con- 
stant K   is  obtained  from  the  following 
table,  which  is  for  air  core  coils. 
h/zr  K  h/2r  K 

6  1.81  0.8  1.10 

5  1.64  0.6  1.07 

4  1.74  0.4  .94 

3  1.37  0.2  .69 

2  1.26  0.1  .49 

1  1.12  0.05  .28 

Having  determined  the  distributed  ca- 
pacity of  a  coil,  what  are  we  going  to  do 
with  this?  The  only  thing  that  we  are 
trying  to  do  with  it  is  to  decrease  its 
value  in  the  coil  as  much  as  possible.  There 
are  several  methods  of  decreasing  the  so- 
called  dead-end  effects  in  radio  coils.  The 


I 

III 

m 

m 

ill 

Hg.  6 

© 

Radio   Inductances   Have  Their  Distributed 
Capacity   Reduced  by  Winding  the  Coils  in 
Groups,  With   a  Space  Between. 

best  and  most  practical  way  is  to  discon- 
nect the  portion  of  the  winding  which  is 
not  in  use  and  this  is  what  may  be  ac- 
complished by  employing  a  special  switch 
arrangement  on  the  coil.  A  highly  ingen- 
ious switch  which  serves  the  purpose  very 
nicely  was  described  in  the  "Question  Box" 

(Continued  on  page  65) 


34 


THE  ELECTRICAL  EXPERIMENTER 


May,  1917 


A  Study  of  the  Law  of  Response  of  the 
Silicon  Detector 


A  "WIRELESS"  AUTO  RADIATOR 
EMBLEM  FOR  AUTOS. 

The  base  of  this  nifty  and  appropriate 
auto  emblem  is  made  from  an  irregular 
shaped  piece  of  wood,  lA  inch  thick  and 
about  8  inches  long,  by  3l/2  inches  wide  at 
the  broadest  end.    The  rocky  effect  is  ob- 


Something  New  in  a  "Wireless"  Radiator 
Emblem  for  Radio  Enthusiasts  Who  Own 
a  Car.  By  Pushing  a  Button  on  the  Dash, 
Sparks  Are  Caused  to  Jump  a  Small  Gap 
Inside  the  Miniature  House. 


tained  by  mixing  thin  glue  and  plaster  of 
paris  and  water  to  a  thick  paste  and  mould- 
ing it  on  the  base,  which  has  several  quar- 
ter inch  holes  bored  through  it,  to  give  the 
plaster  a  secure  foundation.  Papier-mache 
is  very  good  for  the  purpose  or  the  base 
can  very  well  be  moulded  from  white  metal 
or  lead  and  afterward  painted.  The  radio 
masts  and  connections  will  then,  of  course, 
have  to  be  especially  well  insulated.  The 
coil  and  condenser  must  be  kept  close  to 
the  spark  gap. 

One  of  the  masts  is  8  inches  long  and 
the  other  4  inches  long,  made  of  3/16  inch 
brass  or  steel.  The  longer  one  is  sunk 
into  the  plaster  about  two  inches  and  the 
shorter  one  about  1  inch.  The  spreaders, 
%  by  2l/2  inches,  are  equally  divided  for 
the  four  wires  which  are  of  No.  24  bare 
copper.  The  lead  in  rattail  is  soldered  to 
the  middle  of  the  aerial.  The  insulators 
are  tiny  drops  of  black  sealing  wax  mould- 
ed in  ball  fashion  about  the  wire. 

Ropes  of  fine  fish  line  and  guys  of  silk 
cord  are  put  on,  also  a  station  constructed 
of  cardboard  is  placed  at  the  base  of  the 


Circuits  of  Miniature  Radio  System  Used  as 
Radiator  Decoration  for  Autos.  Be  Sure  to 
Show  Your  Credentials  to  the  Village  "Con- 
stabile,"  or  By  Heck,  He  May  Take  You  for 
a  "Spy,"  with  a  Consarned,  New-fangled 
"Wireless."  Yessiree. 

taller  pole.  The  whole,  except  the  aerial, 
is  given  two  coats  of  enamel,  the  poles 
being  white  and  the  ground  and  rocks  of 


THE  special  form  of  silicon  detector 
receiver  designed  by  E.  Merritt  for 
use  with  short  electric  waves,  and 
reported  upon  at  the  meeting  of  the  Physi- 
cal Society,  February  27,  1915,  showed  cer- 
tain peculiarities  which  made  desirable  a 
further  study  of  the  device.  The  investi- 
gation described  in  the  following  paper  by 
Louise  S.  McDowell  and  Frances  G.  Wick 
in  the  Physical  Review,  includes,  first,  a 
study  of  the  receiving  device  and  the  condi- 
tions under  which  it  can  be  used  to  best 
advantage,  and,  secondly,  a  study  of  the 
law  of  response  of  the  silicon  detector  with 
a  variation  in  the  energy  of  the  incident 
wave  produced  by  the  rotation  of  a  screen 
of  parallel  wires. 

The  oscillator,  receiver  and  screen  were 
arranged  as  shown  in  diagrarri.  The  oscil- 
lator S  consisted  of  a  small  spark  gap  in 
kerosene,  extended  by  two  straight  alumi- 
num wires  WW,  to  a  length  of  51  cm.,  and 
connected  thru  water  resistances,  HH,  to 
the  secondary  of  a  small  automobile  induc- 
tion coil,  K,  using  about  6  volts.  The 
water  resistances  introduced  served  to 
damp  any  oscillations  from  the  coil  which 
might  have  produced  disturbances. 

The  receiver  consisted  of  a  silicon  detec- 
tor, D,  in  series  with  a  paper  telephone  con- 
denser, C,  of  1  mfd.  capacity,  and  with  a 
loop  of  wire,  NR.  The  connections  to  this 
loop  were  made  by  mercury  cups,  MM.  A 
sensitive  galvanometer,  Gal.,  Leeds  &  North- 
rup  type  H,  was  shunted  around  the  con- 
denser. An  aluminum  rod,  OP,  acting  as 
a  resonator,  was  supported  parallel  and 
close  to  the  outer  wire  of  the  loop.  The 
length  of  the  resonator  was  44.5  cm.,  giv- 
ing the  maximum  response  to  the  wave- 
length used,  about  100  cm. 

Between  the  receiver  and  the  oscillator 
and  parallel  to  them  was  placed  a  screen, 
EF,  which  could  be  rotated  thru  known 
angles.  It  consisted  of  iron  wires  stretched 
parallel  to  each  other  about  3  cm.  apart, 
upon  a  wooden  frame  2  metres  square.  An 
additional  fixt  screen  of  tin  and  wire  net- 
ting, YAB,  3  metres  high  and  4  metres 
broad,  completely  divided  the  room,  except 
for  an  opening,  AB,  left  in  the  center.  The 
rotating  screen  was  placed  close  to  this 
opening,  on  the  side  toward  the  receiver, 
at  distances  varying  from  5  cm.  to  10  cm. 
for  different  sets  of  observations. 

Merritt,  in  his  experiments  with  the  re- 
ceiving device,  had  noted  that  when  the 
screen  was  placed  with  its  wires  parallel  to 
the  oscillator,  the  position  which  should 
allow  no  transmission,  there  was  still  con- 
siderable effect  upon  the  receiver,  amount- 


green  and  gray  respectively.  The  copper 
wires  are  lacquered  after  being  polished. 
Two  heavily  insulated  wires  (secondary 
cable)  are  then  run  up  thru  the  hood 
of  the  car  from  a  spark  coil  and  condenser, 
which  are  operated  from  a  push  button  on 
the  dash  or  wheel,  the  same  as  a  horn  is 
controlled.  These  wires  are  connected  to 
a  brass  wire  spark  gap  of  about  V\  inch, 
which  has  been  previously  moulded  into 
the  plaster  and  which  the  station  building 
conceals.  If  an  ordinary  ignition  coil  is 
used,  then  a  suitable  condenser  may  be 
formed  of  about  four  4x5  glass  plates, 
coated  on  both  sides  with  tinfoil  leaves  1 
inch  smaller  all  around.  Connect  as  shown 
in  cut. 

The  rest  is  easily  imagined.  The  sur- 
prise at  the  sight  of  the  tiny  flashing  win- 
dows and  the  crash  of  the  spark  gap  is 
bound  to  command  attention  from  anyone. 
Try  it  boys  and  see  if  I'm  right. 

Contributed  by  LES  GLEIM. 


ing  at  the  least  to  about  one-fifth  of  the 
maximum  effect,  when  the  wires  were  verti- 
cal (the  position  for  complete  transmis- 
sion). The  cause  of  this  residual  effect 
was  unknown.  He  observed,  also,  that 
as  the  wire  screen  was  rotated  thru  360 
deg.  there  was  a  variation  in  the  response 
in  the  different  quadrants.  Early  in  the 
present  experimental  work  it  was  found 
that  when  the  resonator  OP,  Fig.  1,  was 
removed  the  receiving  apparatus  still  re- 
sponded, although  weakly,  to  waves  from 
the  oscillator.  The  receiver  was  then 
studied  in  order  to  discover  what  changes 
in  the  design  would  affect  the  response 
without  the  resonator,  and  how  it  could  be 
reduced  to  the  minimum  consistent  with 
sensitiveness  of  the  receiver  as  a  whole; 
also  to  discover  the  cause  of  the  residual 
effect  when  the  screen  was  in  the  position 
of  no  transmission.  Experiments  were 
made  with  the  plane  of  the  receiver  both 
vertical  and  horizontal. 

Receiver  in  the  Vertical  Plane. 

The  receiver  was  mounted  on  a  T-shaped 
board  and  suspended  by  rubber  bands  from 
a  cross-bar  rigidly  fastened  to  the  ceiling. 
To  prevent  reflections,  practically  all  re- 
movable metal  was  taken  from  the  room 
and  from  the  adjoining  rooms.  To  re- 
duce any  difficulties  arising  from  reflections 
from  surrounding  metal  objects,  the  room 
was  completely  divided  cross-wise  by  the 
fixt  screen  described  above,  and  the  ro- 
tating screen  was  placed  in  front  of  the 


Miniature  Radio  Transmitter  and  Receptor, 
With  Screen  E-F  Interposed  Between  Them 
and  By  Which  Means  the  Law  of  Response 
of  the  Silicon  Detector  Was  Studied. 


opening.  The  residual  effect  was  then 
found  to  be  considerably  reduced. 

The  screen  was  then  rotated  thru 
360  deg.  and  readings  were  taken  every 
20  deg.  both  with  and  without  the  resona- 
tor. From  the  observations  made  three 
curves  were  plotted,  in  which  the  ordinates 
were  galvanometer  deflections  and  the  ab- 
scissae the  angles  between  the  parallel 
wires  of  the  rotating  screen  and  the  ver- 
tical. 

The  curve  obtained  with  the  resonator 
had  a  maximum  at  15  deg.  and  a  minimum 
at  100  deg.,  whereas  without  the  resonator 
four  maxima  at  the  45  deg.  positions  were 
obtained.  Curves  taken  out  of  doors  were 
similar  in  form  to  those  obtained  indoors. 

To  determine  the  effect  of  the  design  of 
the  receiver  upon  the  response  without  the 
resonator,  series  of  observations  were  made 
with  loops  of  various  shapes  and  sizes.  To 
get  the  effect  upon  the  loop  alone,  the  re- 
ceiver was  screened  by  a  tin  cylinder  up 
to  the  mercury  cups  MM.  To  test  the  re- 
sponse to  the  vertical  and  horizontal  com- 
(Continued  on  page  74) 


May,  1917 


THE  ELECTRICAL  EXPERIMENTER 


35 


AUXILIARY  RELAY  BREAK  FOR 
COHERERS. 

While  the  coherer  is  used  but  little  in 
modern  radio  receiving  sets,  still,  it  is 
quite  invaluable  in  making  wireless  demon- 
strations at  lectures  and  for  other  radio 
control  experiments. 

One  of  the  principal  troubles  develop- 
ing in  the  operation  of  the  tilings  coherer 
is  that,  it  is  so  extremely  sensitive  to  every 


Coflerer 


,1 R  Pin 


SYbof 


An   Auxiliary  Contact   Fitted   on  the  Relay 
of  a  Coherer  Set   Serves  to  Cut  Off  Local 
Oscillations  from  the  Coherer. 

little  spark  discharge  in  its  immediate 
neighborhood  and  it  is  invariably  found 
that  the  sparking  at  the  relay  contacts  or 
at  the  decoherer  contacts,  will  set  up  oscil- 
lations which  will  pass  along  the  connect- 
ing wires  of  the  coherer  circuit  and  tend 
to  act  on  it  the  same  as  an  incoming  wire- 
less wave. 

This  trouble  is  overcome  to  a  great  ex- 
tent by  shunting  the  relay  and  decoherer 
contacts  with  high  resistances,  of  the  or- 
der of  2,000  to  4,000  ohms  (wound  non- 
inductively),  and  also  by  the  insertion  of 
choke  coils  in  the  lead  wires  between  the 
coherer  and  main  relay. 

However,  there  is  another  scheme,  not 
so  well-known,  perhaps,  and  which  works 
very  favorably  indeed  with  the  above  pur- 
pose in  mind.  This  consists  of  an  auxil- 
iary contact  on  the  relay  or  decoherer, 
which  so  functions  that  the  coherer  cir- 
cuit is  opened  as  the  relay  or  decoherer 
circuit  "breaks,"  and  thus  the  possibility 
of  locally  produced  oscillations  affecting 
the  coherer  are  greatly  reduced.  Choke 
coils  are  not  necessary  with  such  an  ar- 
rangement, but  if  used  as  an  extra  pre- 
caution, they  can  be  made  up  of  a  fine, 
soft  iron  wire  core  4  inches  long  by  54 
inch  diameter,  wound  with  four  layers  of 
No.  26  gage  insulated  magnet  wire,  con- 
nected as  shown  in  diagram. 

USING  "AUTO"  SPARK  COIL  FOR 
RADIO. 

This  is  a  handy  "hook-up"  for  those 
using  an  auotmobile  ignition  coil  with  three 
terminals,  one  of  them  being  common  to 
both  primary  and  secondary.  By  using  this 
connection     scheme     with     an  ordinary 


DPDTSn 


}\  i7 


Condenser 


To  rec 
set 


m- 


Auto  coil 


How  to  Hook  Up  an  Auto  Ignition  Coil  for 
Wireless  Transmitting. 

D.P.D.T.  knife  switch,  it  becomes  impos- 
sible to  press  the  key  accidently  and  knock 
the  detector  out  of  adjustment  when  re- 
ceiving. 

Be  sure  to  connect  that  blade  of  the 
switch  which  connects  with  the  common 


terminal  of  the  coil  to  the  ground  wires; 
otherwise  a  severe  shock  will  be  received 
if  the  uninsulated  part  of  the  key  is  touched 
while  sending. 
Contributed  by 

GEO.  F.  HARRINGTON. 


SINGLE  VS.  MULTI-LAYER  RADIO 
INDUCTANCES. 

In  the  protection  of  radio  frequency  ap- 
paratus one  of  the  most  important  points 
is  the  insertion  of  choke  coils  to  localize 
properly  the  radio-frequency  energy.  I  do 
not  think  it  is  as  fully  appreciated  as  it 
should  be  that  multiple-layer  coils  are  al- 
most useless  for  this  purpose,  says  Benja- 
min Liebowitz  in  the  February,  1917,  Pro- 
ceedings of  the  Institute  of  Radio  Engi- 
neers. Because  of  their  large  effective  dis- 
tributed capacity,  radio  frequency  currents 
are  propagated  with  great  ease  thru  such 
coils,  and  often  with  disastrous  results. 
Thus,  in  one  instance,  I  employed  as  a 
choke  coil  an  inductance  of  about  600  turns 
of  number  18  B.  and  S.  wire  wound  in  30 
turns  per  layer,  and  burned  out  a  generator 
in  consequence.  I  replaced  this  coil  by  six 
single-layer  spirals,  about  twenty-four 
inches  (61  cm.)  in  inside  diameter,  each 
spiral  having  eighty  turns  of  copper  rib- 
bon 0.50  by  0.01  inch  (1.27  by  0.025  cm.)  in 
section,  insulated  by  paper  ribbon  of  the 
same  section.  The  six  spirals  in  series  had 
somewhat  less  inductance  than  the  multiple- 
layer  coil  first  used,  but  to  currents  less 
than  100,000  cycles  in  frequency  they  were 
an  almost  perfect  barrier.  It  cannot  be 
too  strongly  emphasized  that  distributed  ca- 
pacity is  just  as  undesirable  in  choke-coils 
as  it  is  in  radio  frequency  circuits. 

A  "COIN"  RADIO  DETECTOR. 

Wireless  Bugs,  try  this  on  your  detec- 
tor. Procure  a  ten  cent  piece;  if  not  handy 
try  five  cent  piece.  Put  either  of  the  coins 
in  the  detector  cup  and  proceed  to  adjust 
for  a  "sensitive  spot,  as  you  would  with 
galena.  If  your  are  not  satisfied  with  the 
results,  try  another  coin. 

The  writer  has  experimented  successfully 
with  both  coins,  but  prefers  the  DIME  as 
it  does  finer  work  than  the  NICKEL. 

(Evidently  quality  counts,  for  dimes  are 
said  to  be  more  expensive  than  nickels ! ! 
Next ! ! !— Editor.) 

Contributed  by  WILLIAM  MILLER. 

A  SINGING  SPARK  INTERRUPTER. 

Many  amateurs,  like  that  King  of  long 
ago,  have  muttered  "My  kingdom  for  a  real 
musical  spark."  as  they  struggled  with  the 
stuttering,  stammering  interrupters  usually 
attached  to  small  spark  coils.  The  mere 
note  stamps  them  as  beginners  and  the  big 
fellows  don't  want  to  bother  listening  to 
the  low-pitched  code  emitted  from  such 
stations. 

But  a  great  obstacle  lies  in  their  path  in 
obtaining  the  oft  wisht  for,  high  pitched 
note.  Beside  the  mechanical  difficulties 
there  remains  the  fact  that  when  the  in- 
terrupter is  speeded  up,  the  range  is  short- 
ened, due  to  the  fact  that  the  core  of  the 
coil  does  not  become  thoroly  saturated  with 
magnetism  in  the  short  time  that  the  circuit 
is  closed,  with  the  result  that  the  induced 
currents  in  the  secondary  circuit  are  not  as 
powerful  as  they  should  be. 

The  interrupter  described  herewith  dots 
away  with  mechanical  difficulties  in  a  sim- 
ple and  effective  manner,  the  only  cure  for 
the  above  mentioned  condition  being  to  in- 
crease the  voltage  of  the  supply  current. 
By  doubling  the  voltage  very  good  results 
will  be  obtained  with  the  following  device. 

The  regular  spring  interrupter  is  removed 
from  the  spark  coil  and  mounted  on  a  con- 
veniently sized  base.  Two  uprights  are  cut 
from  T4  inch  square  brass  rod  4  inches 
long.  Both  ends  of  these  rods  are  drilled 
and  tapt  for  an  8-32  screw.    One-half  inch 


A  DRUM  TYPE  ANTENNA 
SWITCH. 

Herewith  is  a  diagram  of  an  aerial 
switch  for  use  in  small  stations.  It  is  of 
the  rotary  drum  type  as  seen.  By  refer- 
ring to  Fig.  1,  it  will  be  noted  that  the 


to  rec  set 


A  Rotary  Control,  Drum  Type  Antenna 
Switch  Is  Easily  Made  on  the  Above  Plan. 

parts  are  numbered  as  follows:  1 — binding 
posts;  2 — electrose  knob;  3 — wooden  cylin- 
der; 4 — brass  segments  on  cylinder;  5 — ■ 
brass  contact  brushes ;  6 — box  (wood  or 
rubber  4x3x2  inches).  The  best  job  is 
made  by  using  a  hard  rubber  cylinder,  sup- 
ported on  two  small  pins  as  shown  at  Fig. 
2.  The  current  for  A  and  G  is  then  car- 
ried thru  the  two  shafts  to  segments  4. 
Contributed  by       HAROLD  DAVIE. 

from  one  end  of  each  rod  a  Y%  inch  hole 
is  drilled  to  pass  the  two  small  round  rods 
H  H,  as  shown  in  the  illustration.  The 
square  rods  are  mounted  on  the  base  as 
shown.  The  round  rods  put  into  place  while 
screws,  S  S,  clamp  the  latter  in  position. 

The  end  of  the  interrupter  spring  is  cov- 
ered with  small  strips  of  mica  held  in  place 
by  thick  shellac.  This  mica  is  to  insulate 
the  spring  from  the  length  of  German  Sil- 
ver wire  which  passes  under  the  spring  and 
is  wrapt  around  the  two  small  brass  rods  as 
illustrated.  The  wire  used  may  be  No.  26 
or  No.  28  bare  German  Silver.  The  wiring 
under  the  base  is  shown  in  dotted  lines. 

To  adjust,  turn  the  vibrator  screw  all  the 
way  out  to  tighten  the  German  Silver  wire 
until  it  raises  the  spring  slightly.  Close 
the  key  and  slowly  turn  the  vibrator  screw 
down  till  the  desired  note  is  obtained. 

The  operation  deoends  upon  the  expan- 
sion and  contraction  of  the  wire  which 
takes  place  at  an  unbelievably  high  rate  of 
speed.  The  note  obtained  is  very  musical 
and  in  connection  with  the  higher  voltage 
in  use,  will  increase  the  range  of  the  set. 


We  All  Desire  to  Have  a  High  Note  Spark. 
Here's  How — A  Piece  of  German  Silver  Wire 
Serves  to  Hold  Back  the  Free  End  of  the 
Vibrator  Spring,  Reducing  Its  Swing  and 
Raising  the  Freguency. 

It  is  advisable  to  renew  the  wire  occa- 
sionally, as  the  heating  crystallizes  the  mole- 
cules and  after  a  certain  length  of  time  will 
refuse  to  respond. 
Contributed  by   THOS.  W.  BENSON. 


36 


THE  ELECTRICAL  EXPERIMENTER 


May,  1917 


M  C2N5TRV1QT2R 

mnr- ir~ h — k — it — \r~ir  ir  .  'jr^r^r~-ir---nr-~ir-ni — irrn 


An  Electrical  Paradox  or  Selective  Lamp  Controller 


THE  average  person  is  always  in- 
terested in  a  puzzle.  When  that 
puzzle  is  electrical,  it  is  certain 
to  appeal  to  the  amateur  experi- 
menter. Can  any  of  you  think 
of  an  arrangement  by  means  of  which  a 
single  pole,  single  throw,  knife  switch  may 
be  made  to  operate  three  different  lamps 
individually,  during  three  successive  inter- 


BY  ALBERT  H.  BEILER 

A  wooden  cylinder,  G,  is  fixt  on  A,  which 
has  brass  segments  fastened  along  its  peri- 
fery  as  shown  at  E.  It  will  be  Seen  that  E 
touches  one  of  the  brass  strips  I.  This 
closes- a  circuit  and  lights  a  lamp.  If  some 
means  could  now  be  employed  to  move  the 
wooden  cylinder  Yz  of  a  revolution,  another 
segment  seen  slightly  under  the  middle 
brass  strip  would  touch  the  strip,  while  the 


■19  7 

Rear*V/ew  of  Arm 


ig.3 
Front  V/etv 


Fig  1 
Reor  V/ew 


Perspective   View  of   Selective   Lamp  Control 
Gear  Wheels  and  Other  Odd  Parts.     At  the 
Unit  with  Gear  Attachment  fo 

vals  that  the  circuit  is  closed?  For  exam- 
ple, if  the  switch  is  closed  once,  light  No. 
1  will  light  and  remain  lit  until  the  switch 
is  opened  again.  It  will  then  go  out.  If 
the  switch  is  again  closed,  light  No.  2 
ONLY  will  light  and  remain  lit  until  the 
circuit  is  again  opened.  Similarly  with  light 
No.  3. 

To  secure  the  result  described,  an  ar- 
rangement is  employed  somewhat  similar 
to  that  used  on  the  automatic  block  signal- 
ing systems  of  single-track  electric  rail- 
roads, and  elsewhere.  A  commutator  is 
made  to  move  from  one  contact  segment  to 
another  every  time  an  electro-magnet 
draws  its  armature  down  (or  up). 

Referring  to  Figs.  1  and  3,  when  the  cir- 
cuit is  closed,  the  magnets  attract  the  arV 
mature,  pulling  it  down.  The  hook  C 
catches  over  a  tooth  of  the  ratchet  wheel 
R.  By  noting  the  direction  of  pitch  of  the 
teeth,  it  will  be  seen  that  the  movement  of 
the  hook  will  not  cause  the  ratchet  to  move. 
The  ratchet  is  rigidly  attached  to  a,  shaft 
B,  on  which  a  gear  wheel  K  is  also  firmly 
fastened  (Fig.  1).  This  cog  meshes  with 
\  smaller  one,  J,  which  is  tight  on  shaft  A. 


ler  Built  from  a  Telegraph  Sounder,  a  Few 
Left  Is  Shown  the  Brushes  and  Commutator 
■  Rotating  the  Segment  Drum. 

first  segment  would  have  moved  away  from 
the  end  strip.  Another  third  of  a  revolu- 
tion would  cause  the  foremost  segment  to 
touch  the  foremost  I  and  close  another  cir- 
cuit, while  the  other  two  circuits  would  re- 
main open.  When  the  switch  is  closed, 
the  cylinder  with  the  brass  segments,  called 
the  commutator,  will  not  move,  but  the  hook 
will  engage  a  tooth  of  the  ratchet.  Simul- 
taneously a  lamp  will  light. 
When  the  switch  is  now  opened, 
the  lamp  will  go  out  and  the 
same  instant  the  retractile 
spring  T  will  pull  the  armature 
up  again,  since  the  magnets 
have  lost  their  power  of  attrac- 
tion. Hook  C  will  pull  the 
ratchet  up  a  distance  equal  to 
its  (the  hook's)  travel.  This 
distance  is  such  that  the  ratchet 


ratchet  makes  l/12th  of  a  turn,  K  will  also 
turn  l/12th  of  a  revolution.  Thus  the 
third  of  a  revolution  movement,  which  is 
necessary  to  bring  each  segment  under1  its 
respective  contact,  is  accomplished. 

It  is  possible  that  the  reader  who  has  fol- 
lowed this  explanation  carefully  will  ask 
why  the  movement  of  the  ratchet  should  be 
accomplished  by  the  retractile  spring  T 
when  the  magnet  exerts  a  greater  force. 
In  other  words,  why  should  not  the  seg- 
ments change  on  the  down  stroke  of  -the 
armature  instead  of  on  the  up  stroke?  The 
answer  is  this :  Suppose  the  commutator 
turned  if  a  circuit  was  closed  instead  of 
when  it  was  opened,  then,  for  an  instant 
the  lamp  would  light  which  had  just  pre- 
viously been  lit.  It  is  true  that  almost  im- 
mediately it  would  go  out  and  the  required 
lamp  would  light  but  the  result  would  very 
obviously  be  unsatisfactory.  The  time  taken 
for  the  cylinder  to  commutate  would  be  the 
time  required  for  the  magnets  to  pull  the  ar- 
mature down.  As  this  does  not  occur  in- 
stantaneously, the  above  described  result 
would  occur.  Another  objection  to  having 
the  commutator  rotate  on  the  down  stroke 
of  the  armature  is  that  a  segment  and  a 
brass  strip,  each  carrying  current,  would  be 
separated  from  each  other  by  the  movement 
of  the  commutator  and  create  a  spark 
which  would  soon  pit  the  segments  and 
brass  contacts  and  thus  interfere  with  the 
satisfactory  operation  of  the  device.  With 
the  device  arranged  as  just  described  the 
commutator  moves  an  instant  AFTER  the 
circuit  has  been  opened,  thus  preventing  any 
arc  from  forming. 

The  wiring  diagram  is  shown  in  Figure 
8.  B  B  B  are  the  strips  I  of  Figure  1. 
C  represents  the  commutator  segments.  M 
is  the  electro-magnet.  R  is  the  rheostat, 
made  of  salt  water  with  carbon  electrodes, 
or  sulfuric  acid,  and  carbon  or  lead  elec-' 
trodes.  Two  100  watt  lamps  in  parallel  may 
be  connected  in  series  with  the  magnet  in- 
stead of  the  rheostat.  The  magnets  must 
receive  from  V/2  to  2  amperes,  since  they 
have  quite  a  pull  to  make.  The  smaller 
circles  B  show  where  the  wires  from  the 
device  are  connected  to  the  .binding  posts 
seen  in  Fig.  1. 

Anyone  sufficiently  interested  may  make 
one  of  these  contrivances  by  following  the 
diagrams  and  instructions  which  follow. 


will  ha vp  rnmnlptpd  1  /12th  nf  a  Photo  of  Selective  Lamp  Switch  or  Controller  as  Built 
will  have  completed  i/iztn  01  a  thg  Authorj  Together  with  Three  Lamps  to  Be  Con- 
revolution   when   the    armature  trolled  and  Main  Circuit  Switch. 

shaft  F  strikes  its  stop  screw 
N.    It  must  here  be  stated  that  th.e  ratchet 
has   12  teeth,   gear   K,   48  teeth,  while 
gear  J  has   12  teeth ;  the  ratio  between 
the  two  latter  being  4  to  1.    When  the 


Secure  an  old  telegraph  sounder  of  the 
sort  that  is  generally  sold  to  amateurs  for 
practising  telegraphy.  Unscrew  the  parts 
from  the  base  and  mount  the  frame,  mag- 


May,  1917 


THE  ELECTRICAL  EXPERIMENTER 


37 


nets  and  armature  on  4  columns  consisting 
of  six  l/%  inch  fibre  washers,  the  whole  being 
mounted  upon  a  suitable  baseboard  of  9 
inches  by  6  inches  oak  (Fig.  3).  The  piece 
L  is  of  Yi  inch  brass  Y\  inch  long  and  is 
threaded  at  both  ends  so  as  to  receive  the 
adjusting  screw  of  spring  T  at  one  end 
and  a  screw  that  holds  L  to  the  base  at  the 
other  end.  One-and-one-half  inch  stove- 
bolts,  Q,  hold  the  frame  of  the  sounder  to 
the  base.  The  machine  screws  to  hold  the 
magnets  must  be  2  inches  long  in  order  to 
go  thru  the  base,  the  washers,  the  yoke  of 
the  magnets  and  finally  screw  into  the  mag- 
nets themselves. 

Then  shape  a  hook  of  %  or  3/32  inch 
stock,  as  shown  in  Fig.  2.  A  fret  saw  may 
be  used  to  cut  it  out  with,  but  any  one  at 
all  handy  with  a  file  can  shape  the  hook 
quite  as  well. 

Now  remove  the  armature  of  the  sounder 
by  pressing  the  uprights  outwards.  Drill 
and  tap  a  hole  for  an  8/32  screw  Y\  inch 
from  the  end  of  the  armature  shaft  (Fig. 
7).  Slip  an  8/32  machine  screw  into  the 
upper  hole  of  the  hook  and  screw  it  into 
the  armature,  so  that  the  hook  swings  easily 
but  has  very  little  play.  Lock  the  bolt  on 
the  other  side  of  the  armature  by  a  nut  M. 
The  armature  now  looks  as  in  Fig.  7. 

The  commutator  is  made  from  a  small 
wooden  cylinder  having  a  hole  bored  thru 
it  longitudinally.  Brass  segments  are 
screwed  round  it,  in  a  manner  to  be  de- 
scribed. The  author  found  considerable 
difficulty  in  securing  a  cylinder  of  suitable 
size,  but  he  finally  used  one  of  the  small 
wooden  rollers  on  which  the  paper  for  add- 
ing machines  is  wound.  Such  a  cylinder  is 
$Y%  inches  long,  %  inch  in  diameter  and  has 
a  7/16  inch  hole  thru  it,  and  will  answer 
very  well  for  the  purpose. 

Cut  a  piece  of  1/64  inch  brass  as  shown  in 
Fig.  4  and  drill  small  holes  near  the  corners 
as  indicated.  The  brass  is  attached  to  the 
cylinder  by  small  '4  inch  brass  screws.  Screw 
one  segment  of  brass  down  on  the  cylin- 
der near  one  end,  then  bend  the  brass 
around  the  cylinder  and  screw  the  second 
segment  on.  A  reference  to  E  and  G  of 
Fig.  1  will  serve  to  make  this  clear.  Be- 
fore screwing  the  last  segment  down,  drill 
a  small  hole  diametrically  thru  the  roller 
to  meet  the  central  hole,  and  pass  a  thin 
wire  thru  it,  so  that  the  wire  is  underneath 
the  last  segment.  The  other  end  of  the 
wire  should  come  out  thru  the  last  hole  in 
the  cylinder.  It  will  now  be  evident  that 
there  is  an  electrical  connection  from  the 
protruding  wire  to  every  commutator  seg- 
ment. 

The  shaft  for  the  commutator  is  made  of 


Wiring  Scheme  for  the  "Electrical  Paradox" 
Which  Enables  the  Manipulator  to  Success- 
sively  and  Individually  Light  and  Extin- 
guish Any  One  of  Three  Lamps,  by  Simply 
Operating    the    Main    Switch    Three  Times. 

7/16  inch  steel  or  brass,  inches  long. 
The  details  for  it  are  shown  at  A  (Fig. 
5).  Force  the  shaft  into  the  hole  in  the 
cylinder  so  that  it  projects  the  same  dis- 
tance from  either  end.    While  putting  the 


.11 


19  dr/tt 


Ratchet  hook 
fig.  2 


-D- 


® 


Fig.  6 


shaft  in,  the  wire  that  comes  thru  the  hole 
will  be  caught  between  the  shaft  and  the  in- 
side wall  of  the  cylinder,  so  that  an  electri- 
cal circuit  is  established  from  the  shaft  to 
all  the  segments  of  the  commutator.  The 
brushes  I  (Fig.  1)  that  bear  against  the 
segments  are  of  J/4  inch  wide  spring  brass. 
Three  of  these  are  needed,  3  inches  long. 
They  are  supported  on  the  two  oak  blocks 
H  H,  33/s  inches  long,  by  V/2  inches  wide 
and  y2  inch  thick.  One  of  the  oak  blocks 
must  have  three  small 
holes  thru  it  so  that 
the  holes  are  vertical 
as  the  blocks  stand  on 
end.  The  outer  two 
holes  are  9/16  inch 
from  the  end,  and  the 
inner  one  is  in  the  cen- 
ter. These  holes  are 
for  the  wires  which 
connect  the  brushes  to 
the  binding  posts. 
Drill  y»  inch  holes  in 
the  brass  strips  as 
shown  (Fig.  1)  but  do 
not  fasten  them  to  the 
oak  blocks  until  later. 

Procure  a  ratchet 
wheel  R  (Fig.  3)  V/&' 
inches  in  diameter,  and 
l/$  inch  thick,  also  two 
cog  wheels,  J  and  K 
(Fig.  1),  K  being  1^4 
inches  long  and  having 
48  teeth,  and  J  having 
12  teeth.  The  larger 
cog  and  the  ratchet 
should  each  have  a  Y\ 
inch  hole  thru  their 
centers,  the  smaller 
cog  a  3/16  inch  hole. 

Then  turn  a  shaft  B, 
the    details    of  which 
are  given  in  Figure  5. 
The  end  bearings  for 
the    two    shafts  are 
made  of  3/32  inch  or  Y&  inch  wrought  iron. 
They  may  be  shaped  as  shown  at  X  (Fig. 
3)  or  V  (Fig.  1).    Bearing  X  has  a  Vs  inch 
hole  drilled  13/16  inch  up,  and  Y  has  a  Ys 
inch  hole  drilled  1  1/16  inches  up  from  the 
bottom.    The  center  bearing  D   (Fig.  1) 
must  be  wider  than  the  other  two  since  it 
supports  both  shafts.    The  details  for  its 
construction  are  shown  in  Fig.  6.  The 
holes  should  be  laid  out  very  carefully  and 
accurately,  as  upon  them  depends  the  prop- 
er meshing  of  the  two  cogs,  and  conse- 
quently the  smooth  operation  of  the  con- 
trivance. 

The  uprights  U  and  Y  are  made  of  Y% 
inch  brass  or  steel.  They  are  threaded  at 
the  lower  end  so  as  to  be  held  down  to  the 
base  by  nuts.  U  should  be  about  2Y  inches 
high  and  Y,  2  inches.  Three-eighths  inch 
from  the  top  of  Y,  drill  and  tap  a  hole 
diametrically  thru  it,  to  receive  an  8/32 
spring  adjusting  screw.  On  U  solder  a 
cross-piece  which  has  an  adjusting  screw 
and  lock  nut  N  in  it.  Place  U  so  that 
when  it  is  screwed  down,  N  will  touch  the 
center  of  the  armature  shaft.  Y  is  direct- 
ly in  front  of  the  ratchet,  but  far  enough 
away  so  as  not  to  interfere  with  the  rat- 
chet's operation. 

The  parts  are  now  ready  for  assembling. 
First  put  the  armature  shaft  back  into  its 
supports.  Then  place  the  small  bearing  X 
in  such  a  position  that  when  the  ratchet  is 
put  on  the  shaft  and  the  shaft  into  the 
bearing  the  hook  will  engage  a  tooth  of  the 
ratchet.  (Be  careful  to  have  the  direction 
of  pitch  of  the  ratchet  just  as  shown  in  Fig. 
3  and  not  the  reverse  way.)  When  the  po- 
sition of  bearing  and  of  the  ratchet  have 
been  determined,  solder  the  latter  to  shaft 
B  in  the  required  position,  and  also  solder 
cog  K  to  B,  about  1/16  inch  from  the  end 
of  the  shoulder.  Bearing  X  may  now  be 
screwed  down. 


Pass  the  long  shoulder  of  shaft  A,  i.e.,  the 
left  end  (Fig.  5),  thru  the  upper  hole  of 
bearing  D.  Then  force  the  small  cog  J  on 
to  this  long  shoulder  far  enough  so  that 
there  is  very  little  play,  but  not  so  far  as 
to  cause  the  cog  to  bind  on  the  bearing. 
Now  place  the  cog  wheel  end  of  shaft  B 
into  the  lower  hole  of  D,  and  if  the  work 
has  been  done  correctly,  the  cogs  will  mesh 
with  each  other.  Then  slip  bearing  Y  on 
to  the  other  end  of  the  commutator  shaft. 


Commutator  shaft 
  s"  


IT 


-3- 


Ratchet  shaft 
Fig  5 

f4c  drill 


holes  drilled '/ 
from  each  side 


flow  to  cut  commutator  segments 
Fig  4  _ 


Detail  Working  Drawings  of  Parts  Necessary  in  Constructing  the 
"Electrical  Paradox." 

After  a  little  experimenting  to  place  the 
bearings  in  such  a  position  as  to  make  the 
parts  turn  with  as  little  friction  as  possible, 
screw  bearing  D  and  Y  down  (after  shaft 
B  is  in  position  of  course).  Before  screw- 
ing Y  down,  drill  a  small  hole  thru  the 
base  directly  beneath  it  ar  J  pass  a  thin  wire 
thru  this  hole  so  that  the  bearing  will  press 
on  the  wire.  Connect  the  other  end  of  the 
wire  underneath  the  base  to  a  binding  post. 
It  will  now  be  noticed  that  contact  is  es- 
tablished from  the  binding  post  to  bearing 
Y,  from  Y  to  the  shaft  A,  and  from  there 
to  the  commutator  segments  E  E  E. 

Place  the  oak  blocks  parallel  to  the  com- 
mutator, at  equal  distances  on  either  side 
of  it  and  3  inches  apart.  Drill  3  small  holes 
thru  the  base  at  places  to  correspond  with 
the  3  holes  in  one  of  the  blocks.  Then 
fasten  the  blocks  down  to  the  base  with 
screws.  (It  must  be  clearly  understood 
that  the  screws  DO  NOT  go  thru  these 
holes,  but  thru  other  holes  which  may  be 
bored  for  the  purpose.)  Pass  a  wire 
thru  each  of  the  holes  in  the  base 
and  thru  the  block,  so  that  they  project 
from  the  top.  Now  screw  the  brushes  down 
on  the  blocks  (this  time  the  screws  go 
thru  the  holes  in  the  block).  Connect  the 
three  wires  from  the  under  side  of  the 
base  to  three  binding  posts.  Contact  is 
now  established  from  each  binding  post  to 
each  brush  and  to  that  commutator  segment 
which  happens  to  be  touching  that  brush 
at  the  moment.  Connect  one  of  the  wires 
from  the  magnet  to  a  binding  post  and  the 
other  wire  splices  on  to  the  wire  coming 
from  bearing  Y.  (Refer  to  Fig.  8.)  Put 
a  light  brass  spring  S  thru  the  hole  in  C 
and  hook  it  over  the  spring  adjusting  screw 
in  Y,  so  that  it  can  be  adjusted  to  any  ten- 
sion. The  spring  T  is  of  fairlv  heavy  steel, 
since  it  is  its  tension  that  really  drives  the 
(Continued  on  page  74) 


38 


THE  ELECTRICAL  EXPERIMENTER 

An  Illuminated  Stage  Sulky 


May,  1917 


SEVERAL  years  ago  the  author  of  this 
article  had  occasion  to  work  up  an  illu- 
mination scheme  for  a  small  two-wheel 
sulky  and  harness  to  be  used  in  a  stage  act. 

Owing  to  the  fact  that  the  horse  in  this 
act  performed  many  difficult  tricks,  with 
the  result  that  the  sulky  was  pitched  at 


Appearance  of  Electrically  Illuminated  Stage 
Sulky  and  Harness. 


many  different  angles  and  also  for  other 
reasons,  storage  batteries  were  not  allow- 
able. The  scheme  shown  diagrammatically 
herewith  was  successfully  developed  and 
applied  and  the  results  were  very  satisfac- 
tory, particularly  when  the  display  of  the 
illuminated  harness  and  vehicle  was  shown 
on  a  darkened  stage  before  black  velvet 
drop  curtains. 

Briefly  considered,  the  battery  comprised 
36  dry  cells  of  standard  size,  connected  in 
series-parallel  to  give  18  volts.  The  feed 
wires  in  the  battery  box,  which  was  painted 
white  to  correspond  with  the  trimmings  of 
the  balance  of  the  vehicle  and  placed  be- 
neath the  seat,  were  led  to  the  various  cir- 
cuits about  the  sulky  body  and  wheels  and 
also  to  the  harness. 

The  harness  display  consisted  of  a  num- 
ber of  16  volt  battery  lamps  connected  on 
parallel,  the  terminal  wires  ending"  in  a 
separable  connector,  so  that  it  could  be  in- 
stantly detached  from  the  vehicle  when  de- 
sired. 

A  small  switch  placed  in  one  of  the  main 
battery  leads  and  arranged  on  the  side  of 
the  seat  frame,  enabled  the  driver  to  switch 
on  the  lights  at  the  critical  moment  when 
the  stage  had  been  properly  darkened. 


By  HARRY  S.  TOWNSEND 

that  it  would  be  unnoticeable  to  those  in 
the  audience.  The  rear  (facing  the  au- 
dience j  side  of  the  disk  was  painted  white, 
the  same  as  the  wheels. 

Three  sixteen  volt  lamps  were  placed 
on  every  other  spoke  and  several  lamps 
were  also  secured  to  the  fiber  disk  on  its 
rear  face  so  as  to  form  a  circle  in  con- 
junction with  the  inner  lamps  of  the  spoke 
strips.  Lamps  were  also  spaced  in  be- 
tween, around  the  rims  of  the  wheels,  as 
seen  in  the  illustration. 

A  detail  of  the  round  woven-wire 
brushes  and  brush  holders  is  given  in  the 
illustration.  The  wiring  was  done  with 
No.  14  rubber  covered 1  conductor  for  the 
main  battery  leads,  and  with  No.  16  R.C. 
fixture  wire  for  the  independent  circuits. 

This  arrangement,  as  will  be  observed 
by  the  reader,  does  away  entirely  with 
the  nuisance  of  a  trailing  stage  cable, 
which  many  electrical  acts  are  burdened 
with.  Altho  not  shown  here,  the  various 
circuits  were  specially  arranged  so  as  to 
permit  grouping  into  series — parallel  on 
110  volt  lighting  circuits  when  the  occasion 
demanded.  This  required  4  contact  rings 
and  4  brushes  on  each  wheel,  also  a  spe- 
cial disposition  of  the  harness  and  vehicle 
circuits. 


Rear  View  of  Sulky  Showing  the  Battery  Box  and  Control 
Switch  Within  Easy  Reach  of  the  Driver. 


One  of  the  most  difficult  problems  was 
to  convey  the  current  properly  to  the  ro- 
tating lamp  strips  secured  to  the  spokes 
of  the  wheels.  This  was  accomplisht  by 
means  of  two  brushes  and  a  two  ring 
commutator  fitted  to  the  side  of  each 
wheel. 

The  commutator  disk  was  made  of  fiber 
and  not  more  than  9  inches  in  diameter  so 


HOW  TO  MAKE  CARDBOARD 
CYLINDERS. 

Those  radio-bugs  who  construct  their 
own  loose  couplers  and  loading'  inductances 
are  generally  hampered  by  not  being  able 
to  construct  suitable  forms  on  which  to 
wind  the  wire.  The  following  method  I 
have  found  satisfactory  and  it  takes  but  a 
few  minutes  to  construct  a  serviceable 
tube  of  any  desired  size  and  thickness. 

Having  the  plugs  of  the  desired  diameter 
ready,  cut  off  a  strip  of  thin  cardboard  slight-, 
ly  greater  in  width  than  the  required  length 
of  the  tube  to  be  made.  Now  lay  the  card- 
board on  the  table  and  proceed  to  roll  the 
plugs.  After  making  one  revolution  spread 
glue  liberally  over  the  remaining  part  and 
finish  rolling  it  up.  If  the  tube  is  not  as 
thick  as  desired,  another  strip  of  cardboard 
can  be  wound  over  the  first.  It  is  well  not 
to  have  the  tube  fit  too  tightly  over  plugs, 
or  trouble  will  be  exper- 
ienced w  i  t  h  shrinkage 
during  further  treatment. 
The  tube  is  now  wound 
with  tape  or  cord  and 
placed  in  a  moderately 
hot  oven  for  fifteen  min- 
utes or  more. 

After  removing  from 
oven,  trim  edges  carefully 
and  while  still  hot  give  it 
a  thoro  coating  of  orange 
shellac  inside  and  out. 
While  the  shellac  is  still 
fresh,  take  your  blow 
torch  and  with  a  sweeping 
movement  burn  the  shel- 
lac into  the  tube  and  re- 
peat the  process.  It  is 
well  to  make  sure  you  are 
using  pure  shellac,  not 
cheap  glue,  as  some  so- 
called  shellacs  are  (I 
make  my  own  shellac  out 
of  orange  shellac  flakes 
dissolved  in  grain  alcohol).  If  you  do  not 
have  a  blow  torch  handy,  a  good  heating  in 
the  oven  will  do  altho  it  requires  more  time. 

The  appearance  of  the  tube  is  greatly  im- 
proved by  blackenine  the  ends.  A  thin 
paste  made  up  of  black  aniline  dye,  dis- 
solved in  white  shellac,  gives  a  glossy  black. 
A  black  looking  luster  can  be  made  of  lamp- 
black mixed  with  orange  shellac.    The  for- 


n.er  is  preferable,  having  better  insulating 
qualities  than  the  latter. 

A  little  experience  in  tube  making  will 
soon  make  you  proficient  in  the  art.    At  a 


Sockets 


Hole  for  hub,  *«st 
'enfhmoch.       ■  ' 


Details  of  Sulky  Wheels  and  the  Metal  Con- 
tact Rings  and  Brushes  Whereby  Current  Is 
Conducted  to  the  Lights  on  the  Spokes. 

small  cost  moisture  proof  tubes  can  be  made 
quickly,  saving  valuable  time  in  waiting. 

Contributed  by 

CHARLES  M.  FITZGERALD. 


HOW  TO  FROST  LAMPS  QUICKLY. 

Take  the  bulb  and  smear  over  thoroly 
with  a  good  library  paste ;  after  which  dip 
into  a  cup  of  sugar  or  salt  crystals.  Then 
let  stand  for  awhile.  Do  not  use  glue  for 
an  adhesive  as  this  has  a  tendency  to  dis- 
solve the  salt  or  sugar. 

Contributed  by     JOHN  T.  DWYER. 

TO  USE  OLD  BATTERY  ZINCS. 

When  the  lower  half  of  a  battery  zinc  is 
eaten  away  by  the  action  of  the  electrolyte, 
the  remaining  portion  can  be  utilized  by  sus- 
pending it  from  a  wire,  so  that  the  zinc  is 
covered  by  the  battery  solution. 

A  very  good  electrical  connection  should 
be  made  between  the  wire  and  the  zinc  and 
the  joint  covered  with  melted  paraffin.  This 


© 


_j2 


Hmiiit — iiiiiii"- 
Humii — liimiH 

-O-  36  dry  ce//s  in  ser/es  \po/v//e/ 


-O 

-o- 
-o- 


tlorness  Ig'ts 

1 


Wiring  Diagram  for  36  Dry  Cell  Battery  and 
Various   Lamp   Circuits  on   the   Sulky  and 
Harness. 


last  precaution  is  necessary  as  otherwise 
corrosion  would  soon  occur  from  the  action 
of  the  salammoniac  or  other  chemical.  The 
wire  may  be  held  at  the  top  of  the  jar  by 
twisting  around  a  small  piece  of  wood. 
Contributed  by  K.  M.  COGGESHALL. 


May,  1917 


THE  ELECTRICAL  EXPERIMENTER 


39 


UNIQUE   INDICATOR  SYSTEM 
WHICH    ANNOUNCES  THE 
ICEMAN  AND  GROCER. 

A  "step-saver" — that's  just  what  this  de- 
vice is,  for,  when  constructed,  it  will  save 
Mother  or  the  housekeeper  many  a  fruit- 


Fig  I 


fig  2 


® 


Spring 


6/oss  mndoiv 


'II 

'oai 

t 

=  (III  

  Vie/oii 

Cor  Don  >VJ 


dufomofic  it  re/eose 


The  Women  Folks  Need  Not  Run  to  the 
Door  for  the  Iceman  and  Grocer,  When  This 
Apparatus  Is  Installed.  The  Tradesman 
Turns  the  Switch  Lever  to  the  Proper 
Number;  the  Kitchen  Indicator  Shows  Who 
Is  Calling  and  the  Cook  Pushes  the  Button 
Marked  "Coming"  or  That  Labeled  "Nothing 
To-day." 

less  trip  to  the  door  in  response  to  the 
ever-ringing  bell,  because  it  enables  her  to 
know  who  is  calling,  whether  the  milkman, 
baker,  etc.,  and  signal  to  them  if  their  goods 
are  needed  or  not — all  without  requiring  any 
more  effort  on  her  part  than  merely  pushing 
a  button. 

The  first  thing  required  is  a  wooden 
frame  or  case,  similar  to  that  shown  in 
Figs.  1  and  2.  Inside  of  the  same  are  ar- 
ranged the  indicator  magnets  and  also  the 
magnets  controlling  the  automatic  switch 
release  (A  in  Fig.  1).  This  latter  may  be 
simply  the  armature  and  tapper  rod  of  an 
ordinary  battery  bell,  bent  as  illustrated  in 
order  to  allow  the  extremity  to  act  as  a 
check  pawl  on  the  four-cam  wheel,  which 
is  centered  on  a  shaft  manipulated  by  the 
switch  handle.  It  will  be  seen  that  this 
prevents  the  switch,  when  once  set  at  the 
point  desired,  from  falling  back  to  its 
original  position  after  pressure  has  been 
removed.  The  cam  wheel,  if  not  procurable 
from  old  clock  works,  can  be  easily  turned 
out  of  wood  by  a  jig  saw  or  of  brass  in  a 
lathe.  By  the  same  methods  any  other 
parts  of  this  device  may  be  constructed 
when  lack  of  simpler  means  prevents 
otherwise.  The  carbon  strip  (another  form 
of  resistance  may  be  used  if  this  is  not 
handy)  can  be  cut  out  from  the  carbon 
electrode  of  an  old  battery  cell  and  should 
be  placed  on  the  inside  of  the  box  directly 
over  the  groove,  by  means  of  which  the 
switch  makes  contact  with  it.  The  parti- 
tion B,  in  Fig.  1,  should  have  two  holes  for 
the  insertion  of  the  core  ends  of  the  electro- 
magnets M'  and  M",  which,  on  being  act- 
uated, raise  up  one  or  the  other  gravity  in- 
dicators, Fig.  2.  These  latter  are  merely 
short  lengths  of  steel  wire  bent  as  shown, 
so  as  to  allow  them  freedom  of  motion  up- 


wards. As  can  be  seen  one  is  for  the  pur- 
pose of  signaling  to  the  waiting  tradesman 
that  the  housekeeper  is  coming,  while  the 
other  performs  an  opposite  function,  as  the 
case  may  be. 

Fig.  3  shows  the  indicator  panel  proper, 
which  includes  simply  a  low  resistance  gal- 
vanometer or  ammeter,  two  push  buttons, 
and  a  bell.  If  the  reader  cannot  make  such 
an  instrument,  he  will  hnd  an  admirable 
one  described  in  the  August  issue  of  the 
"E.  E."  Of  course,  it  is  understood  that 
the  scale  card  is  not  marked  off  in  amperes 
but  instead  into  four  divisions,  numbered 
from  one  to  four — each  division  represent- 
ing the  title  of  such  tradesmen  as  call  most 
frequently.  The  front  door  device  is  also 
marked  with  corresponding  numbers  (see 
Fig.  2)  and  a  printed  card  like  that  shown 
should  be  placed  on  it.  It  will  be  neces- 
sary to  experiment  for  a  while  in  order  to 
have  these  numbers  correspond;  that  is  to 
say,  when  the  switch  is  turned  to  Grocer, 
which  is  No.  1,  the  resistance  traversed 
must  be  such  as  to  move  the  needle  on  the 
indicator  also  to  No.  1.  Full  electrical 
connections  are  shown  in  Fig.  4. 

Assuming  that  everything  has  been  com- 
pleted, let  us  suppose  the  Milkman  comes 
and  turns  the  switch  to  No.  4.  Such  action 
allows  more  or  less  current  to  flow  with 
the  result  that,  at  the  same  time  the  bell  is 
rung,  the  indicator  needle  is  turned  also  to 
No.  4  and  all  the  lady  of  the  house  need 
do  is  to  glance  at  the  same  to  ascertain  that 
fact.  If  milk  is  not  wanted,  she  has  only 
to  push  the  button  designated — Nothing 
To-day.  The  current  set  up  actuates  the 
electro-magnet  controlling  the  lower  signal 
and  the  latter  is  raised  upwards,  thus  ac- 
quainting the  tradesman  with  the  fact  that 
his  goods  are  not  required.  At  the  same 
time,  it  will  be  noticed  by  following  out 
the  electrical  diagram  carefully,  that  the 
armature  of  the  switch  return  mechanism  is 
attracted  upwards,  thereby  releasing  the 
check  pawl  and  allowing  the  switch  (which 
has  a  coil  spring  exerting  tension  upon  it) 
to  resume  its  original  position.  The  de- 
vice  is  then   ready  for   the  next  caller. 

Contributed  by  JOHN  T.  DWYER. 
[Editor's  Note  : — We  would  suggest  the  use 
of  a  low  resistance  relay  in  place  of  the 
vibrating  bell,  the  local  circuit  of  the  relay 
being  connected  to  a  bell  and  battery.  This 
permits  the  action  of  the  INDICATOR 
system  to  be  much  more  even  and  accurate. 
This  change  in  the  layout  is  shown  in  sup- 
plemental diagram  Fig.  4.} 

AN  EXPERIMENTAL  SPARK  COIL. 

I  have  just  completed  a  small  "spark 
coil,"  of  my  own  design,  which  embodies 
a  special  feature  of  regulation.  The  full 
strength  of  this  coil,  when  the  primary 
is  all  the  way  within  the  secondary,  is  Y?- 


e  end  piece 

tuoe 
I  t'-fd fiber 

/  fa\ 

P/yrn 


f/der/i/de 


@ 


This  Experimental  Spark  Coil  Has  a  Re- 
movable Primary  Coil  and  Core,  So  That  All 
Sorts  of  Experiments  Can  Be  Tried  With  It. 

inch  heavy  spark,  and  /the  minimum 
Strength  is  "0,"  when  the  primary  is  drawn 
all  the  way  out. 

The  drawing  explains  all  details.  The 
primary  is  made  separate  and  complete 
from  the  secondary  with  binding  posts  at- 


HOOK-UP  FOR  STARTING  UP  TWO 
MOTORS  WITH  ONE  RHEOSTAT. 

Emergency  making  necessary  the  use  of 
limited  equipment  for  connecting  up  two 
10  horsepower  direct  current  shunt  field 
motors,  with  one  starting  box,  I  made  use 
of  the  hook-up  herewith  reproduced  to  start 
up  each  machine  and  connect  it  on  the  main 
line. 

The  first  step  was  to  provide  ample  pro- 


TPDT-7r/pIe  po/e  double  throw  switch 
R-r/?eostof,    f*  so  omp.fuse.  f- 100  amp.  fuse 
S-  shunf  f/'eid.  SS.  -  short/rig  sw/fcf? 
fffiSJ'  douMepote  s/op/e  throw  srv/tcf/  © 


Useful  Kink  Utilizing  One  Starting  Rheostat 
for  Starting  Up  Two  Motors.  After  Each 
Motor  Has  Been  Accelerated  in  Turn,  the 
Proper  Switch  Is  Closed,  Throwing  It  Di- 
rectly on  the  Line. 

tection  against  overloads  and  failure  of 
power,  which  was  overcome  by  properly 
fusing  as  per  diagram. 

With  T.P.D.T.  switch  in  neutral  or 
straight  out  position,  connections  to  the  mo- 
tor are  broken.  Throw  main  switch  in, 
then  T.P.D.T.  to  either  side  to  start  re- 
spective motor.  Bring  rheostat  lever  up 
slowly  to  no-voltage  release  and  lock ;  next 
throw  in  respective  shorting  switch,  when 
handle  on  starter  should  drop,  thus  con- 
necting one  motor  on  the  line. 

To  start  the  second  motor,  throw  T.P.- 
D.T. switch  to  opposite  side  and  start  as 
before,  after  which  close  the  proper  short- 
ing switch.  Both  motors  now  on  the  main 
supply  line;  pull  T.P.D.T.  switch  to  neu- 
tral position. 

I  have  had  entire  success  in  running  both 
motors  by  this  method  for  a  period  of 
30  days,  depending  exclusively  on  the  30 
ampere  fuses  for  overloads  and  manually 
opening  the  circuits  in  case  of  generator 
shut-down  or  cutting  off  of  the  power. 

Contributed  by        RAY  J.  BUTTON. 

tached.  The  secondary  is  wound  upon  a 
spool,  which  also  has  binding  posts  at- 
tache . 

The  primary  unit  comprises  an  iron 
wire  core  6  inches  long  by  lA  inch  diame- 
ter. The  primary  winding  is  of  two  lay- 
ers No.  18  D.C.C.  magnet  wire.  This  is 
covered  with  several  layers  of  waxed 
paper.  The  primary  terminals  are  mounted 
on  a  fiber  disc,  2  inches  diameter,  as 
shown.  The  completed  primary  is  soaked 
in  molten  paraffin  wax.  The  secondarv 
coil  consists  of  lTi  lbs.  No.  34  S.C.C.  mag- 
net wire,  wound  in  layers  onto  a  wooden 
or  fiber  spool,  measuring  4  inches  in  length. 
The  starting  or  inner  lead  of  the  secon- 
dary should  be  well  insulated  by  passing 
thru  a  glass  or  rubber  tube  outside  the 
spool  or  else  by  passing  it  thru  a  hole 
drilled  radially  down  thru  the  spool  cheek, 
this  one  being  made  r4-inch  thick  or  more 
for  the  purpose. 

Contributed  by  CHAS.  S.  PORTER. 


40 


THE  ELECTRICAL  EXPERIMENTER 


May,  1917 


A  Simple  Electric  Motor  Attachment 
for  Phonographs 

By  R.  U.  CLARK,  3rd 


THE  phonograph  is  without  doubt  one 
of  the  greatest  of  all  pleasure  giving 
instruments.  This  fact  is  amply 
demonstrated  by  the  large  number  of  these 
machines  in  use  at  the  present  time.  It 
is,  however,  like  many  other  articles,  ap- 
preciated most  when  new,  and  is  little  used 


at  a  constant  speed  by  the  governor  with 
which  the  talking  machine  is  fitted,  may 
appear  rather  inappropriate,  but,  altho 
some  heating  does  take  place  in  this  motor 
it  is  not  sufficient  to  cause  excessive  wear 
or  shorten  its  life  materially. 

The  actual  method  of  driving  the  talk- 


Illustrating   How  the  Author  Devised  a  Simple  and  Effective  Electric  Motor  Drive  for  a 
Disc  Style  Talking  Machine.    The  Old  Governor  Mechanism  Is  Retained  and  the  Motor  Drives 
the  Record  Table  by  Means  of  a  String  or  Cord  Belt.    (Fig.  1.) 


after  its  novelty  wears  off,  owing  to  the 
constant  attention  required  to  operate  it. 
Winding  up  the  spring  to  keep  the  motor 
going  is  the  one  thing  which  detracts  most 
from  the  pleasure  which  should  be  derived 
from  any  good  talking  machine. 

By  means  of  a  simple  electric  motor  at- 
tachment it  is  at  once  possible  to  do  away 
with  practically  all  the  bother  incident  to 
the  operation  of  the  talking  machine,  with 
the  exception  of  changing  the  records. 

Most  of  the  standard  machines  on  the 
market  today  lend  themselves  very  readily 
to  the  attachment  of  an  auxiliary  motor 
device,  so  that,  by  the  employment  of  a 
little  care  and  ingenuity,  it  is  a  simple 
matter  to  remodel  a  phonograph  so  as  to 
run  it  by  electric  motive  power. 

The  actual  amount  of  power  required 
to  drive  the  turntable  of  most  any  phono- 
graph at  the  proper  speed  is  very  small, 
although  it  may  not  appear  so  to  the  per- 
son who  has  to  be  continually  winding  up 
the  ordinary  spring  motor.  Just  how  little 
power  will  suffice  depends  more  or  less  on 
the  machine  to  be  driven,  but  for  most 
machines  a  universal  electric  motor  of  1/40 
H.P.  will  be  found  quite  sufficient.  These 
motors  can  be  purchased  new  in  most  cases 
•  for  as  little  as  $4  complete,  and  can  be 
attached  by  a  flexible  wire  direct  to  the 
ordinary  lamp  socket,  without  using  any 
extra  resistance.  The  motor  used  by  the 
author  with  considerable  success  was 
bought  originally  as  a  fan  motor  for  $4; 
the  fan,  guard,  and  base  which  came  with 
the  motor  were  removed. 

The  motor  mentioned  above  was  de- 
signed to  drive  a  six-inch  fan  at  about 
3,000  r.p.m.  Under  this  load  the  makers 
claim  it  can  be  run  at  a  cost  of  about  1 
cent  per  6  hours,  the  rate  per  K.W.  being 
10  cents.  This  motor  is  equipped  with 
special  patented  bearings  which  require  no 
oiling;  for  about  2  months,  during  which 
time  the  author's  machine  has  been  run  a 
great  deal,  no  oil  has  been  placed  on  the 
bearings. 

The  use  of  such  a  small  motor,  as  men- 
tioned above,  for  such  exacting  work  as 
running  a  large  turntable,  which  is  held 


ing  machine  turntable  on  which  the  records 
rest,  as  described  in  this  article,  is  by  direct 
belt  connection,  which  method  requires 
perhaps  the  least  accuracy  in  construction. 
The  author  after  considerable  experiment- 
ing with  a  simple  friction  drive,  direct 
from  the  electric  motor  shaft,  which  was 
fitted  up  with  various  rubber  and  com- 
position friction  wheels,  was  forced  to 
give  up  this  method  in  the  favor  of  belt 
drive.  Friction  drive  applied  to  such  a 
mechanism  as  the  phonograph  requires 
very  accurate  construction,  and  even  then 
direct  friction  drive  on  most  machines 
would  prove  noisy  and  unsatisfactory,  due 
to  the  notoriously  imperfect,  peripheral 
arc  described  by  most  talking  machine 
turntables. 

The  first  step  in  the  preparation  of  the 
talking  machine  for  the  addition  of  an 
electric  motor  is  to  run  the  machine  until 
the  spring  is  completely  unwound.  This 
requires  about  fifteen  minutes  time.  The 
spring  motor  and  top  board  is  then  re- 
moved temporarily  from  the  phonograph, 
if  possible,  by  removing  the  crank  handle. 
In  some  machines  it 
is  possible  to  get  at 
the  motor  from  the 
bottom.  As  soon  as 
access  to  the  motor 
is  obtained,  the  gears 
and  shaft,  which 
.  form  the  connecting 
link  between  the 
turntable  shaft  and 
the  spring  motor 
gears  are  removed. 
The  unit  to  be  re- 
moved is  clearly  in- 
dicated in  Fig.  1,  A — 
A.  The  heavy  cen- 
ter line  A — A  which 
passes  thru  the  lower 
part  of  the  spring 
motor  casing  indicates  the  position  of  the 
unit  to  be  tr.ken  out.  Removing  this;  piece, 
by  letting  up  on  the  set  screws,  which  hold 
the  pivot  bearings,  on  which  the  shaft 
mentioned  above  runs,  simply  disconnects 
the  turntable  and  its  shaft  from  the  spring 


motor,  but  does  not  effect  the  speed  gov- 
erning mechanism,  which  is  left  in  place, 
for  use  with  the  electric  motor,  to  control 
the  speed  in  the  usual  manner. 

After  disconnecting  the  spring  motor 
from  the  turntable  shaft,  the  table  should 
be  removed  and  a  small  groove  from  1/32 
to  1/16  of  an  inch  deep,  the  actual  depth 
depending  on  the  thickness  of  the  turn- 
table rim,  should  be  made  for  the  belt  to 
run  in  around  the  outside  of  the  rim.  This 
groove  should  be  about  of  an  inch  wide, 
and  should  not  be  too  near  the  top  edge 
of  the  rim.  On  certain  machines  there  is 
a  narrow  shoulder  located  under  the  rim, 
which  in  some  cases  will  hold  the  belt. 

As  the  phonograph  is  to  be  driven  by  a 
belt  a  small  grooved  pulley  wheel  for  the 
motor  is  necessary.  This  wheel  is  best 
made  of  metal  with  a  small  groove  about 
inch  wide,  either  V  or  semi-circular  in 
cross-section,  and  about  1/16  inch  deep. 
The  greatest  diameter  of  the  pulley  should 
be  about  1  inch  or  under.  The  author 
has  used  experimentally  several  sizes  from 
Y%  inch  up  to  1  inch,  all  with  considerable 
success,  but  when  a  1  inch  wheel  is  used, 
the  motor  which  then  turns  at  about  800 
r.p.m.  seems  to  run  the  quietest,  and  with 
practically  no  belt  slippage.  Within  the 
sizes  mentioned  the  diameter  of  the  pulley 
will  have  little  effect  upon  the  speed  of 
the  turntable,  which  is  still  controlled  by 
its  own  governor  as  mentioned  above,  but 
of  course  the  motor  pulley-belt  speed  will 
be  decreased  by  the  use  of  a  small  pulley 
and  increased  when  a  large  pulley  is  em- 
ployed. A  10  cent  pulley  from  a  mechan- 
ical toy  set  is  satisfactory. 

The  metl.od  to  be  used  in  mounting  the 
motor  will  necessarily  depend  somewhat 
upon  the  type  of  talking  machine  used. 
There  are  two  simple  ways  of  attaching 
the  motor,  one  of  which  should  be  appli- 
cable to  nearly  any  machine  made.  Wher- 
ever the  construction  of  the  talking  ma- 
chine permits,  the  motor  can  be  hung  out 
of  sight,  from  the  top-board  of  the  body 
of  the  phonograph,  with  the  shaft  ex- 
tending thru  this  board  about  ^4  inch, 
so  that  the  pulley  wheel  can  be  mounted 
with  ease  from  the  top  side  of  the  board 
on  which  the  motor  is  hung,  as  shown  in 
Fig.  1.  This  mode  of  mounting  is  possible 
only  with  a  certain  class  of  phonographs, 
mostly  the  larger  sizes.  For  use  with 
small  machines,  where  the  motor  cannot  be 
hung  out  of  sight,  it  can  be  inverted  and 
fastened  to  the  top  board,  in  such  a  man- 
ner that  the  pulley  groove,  which  comes 
next  in  position  to  the  motor  bearing, 
with  the  hub  near  the  outside  end  of  the 
shaft,  comes  in  line  with  the  grooved  por- 
tion of  the  turntable.   (See  Fig  2.) 

To  use  the  method  of  attachment  first 


Where  it  is  Not  Possible  to  Conceal  the  Motor  in  the  Cabinet,  as 
in  Small  Machines,  the  Motor  Can  Be  Readily  Mounted  Above  the 
Cabinet  Shelf  as  Shown.    (Fig.  2.) 


described  it  is  necessary  to  drill  three  holes 
in  the  top  board  spaced  about  2  inches 
from  the  edge  of  the  turntable.  The 
center  hole  is  made  to  accommodate  the 
main  bearing  and  shaft  of  the  motor.  The 
(Continued  on  page  76) 


May,  1917 


THE  ELECTRICAL  EXPERIMENTER 


41 


WOT 
llWliJ 


TV"? 


This  department  will  award  the  following  monthly  prizes:   First  Prize,  $3.00;    Second  Prize,  $2.00;    Third  Prize,  $1.00. 

The  purpose  of  this  department  is  to  stimulate  experimenters  towards  accomplishing  new  things  with  old  apparatus  or  old  material,  and  for  the  most  useful, 
practical  and  original  idea  submitted  to  the  Editors  of  this  department,  a  monthly  series  of  prizes  will  be  awarded.  For  the  best  idea  submitted  a  prize  of  $3.00  is 
awarded;  for  the  second  best  idea  a  $2.00  prize,  and  for  the  third  best  a  prize  of  $1.00.  The  article  need  not  be  very  elaborate,  and  rough  sketches  are  sufficient.  We 
will  make  the  mechanical  drawings.    Use  only  one  side  of  sheet.    Make  sketches  on  separate  sheets. 


FIRST  PRIZE,  $3.00 


A  VOLTMETER  FOR  THE  AMA- 
TEUR ELECTRICIAN. 

Herewith  is  described  an  easily  construct- 
ed voltmeter,  which  will  accurately  register, 


A  Simple  Voltmeter  for  the  Student,  Com- 
prising   an    Electro-magnet    and    a  Pivoted 
Piece  of  Sheet  Iron  With  an  Indicating  Needle 
Attached  as  Shown. 

if  properly  constructed  and  adjusted.  It  is 
very  simple  and  requires  few  materials,  all 
of  which  are  found  around  the  experiment- 
er's shop. 

The  base  was  made  5  by  V/2  by  ]/>  inches. 
The  upright  U  was  made  from  the  same 
material  1  inch  shorter.  Next  I  cut  out  a 
piece  of  tin  from  a  cocoa  can  in  the  shape 
shown  in  Fig.  1;  2  inches  from  1  to  1,  1 
inch  from  2  to  2  and  \l/2  inches  from  3  to  3. 
Two  small  holes  are  put  one  in  each  end. 
Then  I  bent  it  into  the  shape  shown  in  Fig. 
2,  over  a  hammer  handle.  The  pointer  P 
was  made  from  a  piece  of  fine  wire  and 
soldered  on.  A  large  pin  served  as  an  axle, 
H.  The  piece  of  tin  A,  Fig.  3,  holds  one 
end  of  the  pin  while  the  other  end  is  driven 
into  the  upright,  U.  The  magnet  M  was 
taken  from  an  old  bell  and  held  in  position 
by  tin  strips  as  shown.  After  putting  the 
binding  posts,  P,  on  and  fastening  the  up- 
right and  disk  into  position,  the  instrument 
was  complete. 

The  best  way  to  mark  the  disk  is  with  a 
transformer;  mark  where  the  pointer  stays 
in  a  natural  position  with  an  O  Then  con- 
nect five  volts  to  the  binding  posts  and 
mark  where  the  pointer  stays  with  a  5.  Do 
the  same  with  ten  and  fifteen  volts.  Mark 
off  spaces  of  one  volt  each  between  the 
numbers.  This  instrument  will  be  an  inter- 
esting as  well  as  useful  addition  to  the 
shop  for  measuring  various  voltages. 

Contributed  by  FRANK  M.  JACKSON. 

GOLD  LEAF  SUBSTITUTE  FOR 
ELECTROSCOPES. 

Coat  lightly  one  side  of  a  piece  of  tis- 
sue paper  with  lamp  black  and  turpentine 


SECOND  PRIZE,  $2.00 


USING  COMMUTATOR  FOR  WIND 
DIRECTION  INDICATOR. 

Many  people  find  an  electrical  wind  di- 
rection indicator  both  useful  and  practi- 
cal. It  is  very  convenient  to  have  such 
an  installation  in  the  home,  office  or  lab- 
oratory, so  that  by  simply  glancing  at  the 
electrical  annunicator,  one  may  know  just 
how  the  wind  is  blowing,  so  far  as  its 
direction  is  concerned. 

Most  of  those  described  in  the  "How- 
To-Make-It"  columns  of  electrical  jour- 
nals, involve  the  construction  of  a  com- 
mutator or  segmental  switch.  This  diffi- 
culty is  readily  overcome  by  utilizing  a 
small  size  motor  commutator,  which  can 
be  purchased  at  little  cost  from  any  elec- 
trical supply  house  or  dealer,  and  having 
eight  or  more  segments. 

The  commutator  is  made  stationary  on 
the  shaft  standard  supporting  the  weather 
vane,  while  the  moving  lower  part  of  the 
device  attached  to  the  weather  vane 
proper,  carries  at  its  lower  end  an  elec- 
trical contact  brush  (preferably  a  rolling 
ball  or  wheel  contact)  which  of  course 
will  turn  with  the  vane. 

The  moving  part  of  this  apparatus 
should  not  be  too  stiff,  and  the  best  ones 
now  in  use  are  equipt  with  ball  bearings. 
With  a  little  ingenuity  on  the  part  of  the 
builder,  it  will  be  found  possible  to  in- 
corporate the  ball  bearing  feature  with 
very  little  trouble,  and  the  vane  will  be 
many  times  more  accurate  and  reliable 
than  the  ordinary  one.  The  circuit  con- 
nections between  the  moving  brush,  com- 
mutator and  flash  lamp  annunciator  are 
shown. 

Contributed  by       PETER  BROWN. 


Many  Experimenters  Desire  to  Build  an 
Electrical  Weather  Vane,  But  Hesitate  to 
Do  So,  Owing  to  the  Difficulty  in  Construct- 
ing a  Suitable  Multiple  Contact  Switch.  A 
Motor  Commutator  Solves  the  Problem. 

with  a  brush.     Cut  a  2V2xI4  inch  piece 
from  it   for  your  electroscope.  Electro- 
scopes may  be  used  to  test  insulators. 
Contributed  by 

CLARENCE  MELOTZ. 


THIRD  PRIZE,  $1.00 


WHAT  IS  A  SAFE  RETREAT 
DURING  A  THUNDERSTORM? 

Place  a  mouse,  a  bird,  an  electroscope 
and  some  gunpowder  inside  a  wire  gauze 
cover,  such  as  is  used  for  protecting  meat. 


To  tfat/c  mac/7 


G/osj  tumblers 


To  Prove  That  a  Person  Is  Invariably  Safe 
from  Lightning  When  Inside  a  Metallic  Cage, 
Mr.  Weinbrot  Places  Some  Powder,  a  Mouse 
and  a  Bird  Within  a  Metal  Cage.  Heavy 
Static  Sparks  Jumping  to  the  Cage  from  a 
Wimshurst  Machine  Have  No  Effect  on  Any 
of  Them. 


The  whole,  being  placed  on  a  board  is 
supported  on  four  warm,  dry  tumblers 
placed  on  the  top  of  a  table. 

Connect  it  with  a  static  machine  and  set 
it  working.  Altho  an  abundance  of  sparks 
may  be  made  to  play  all  over  the  out- 
side, the  living  things,  the  gunpowder 
and  even  the  electroscope  will  not  be  af- 
fected in  the  least. 

From  this  experiment  one  may  therefore 
deduce  that  the  safest  place  in  a  thunder- 
storm is  in  the  metal  lined  meat  safe,  pro- 
vided, of  course,  that  it  is  large  enough. 
This  also  demonstrates  the  theory  of  Lodge 
regarding  the  design  of  lightning  rods  for 
protecting  buildings.  Lodge  recommends 
for  first-class  protection  that  the  edifice 
should  be  entirely  enclosed  under  a  per- 
fect network  of  wires,  resembling  in  effect 
an  ordinary  bird  cage.  Modern  installations 
of  lightning  rods  follow  this  theory  as 
nearly  as  possible.  The  important  part  to 
bear  in  mind  is,  that  you  should  not  touch 
the  metal,  otherwise  fatal  results  will  oc- 
cur. 

Contributed  by       E.  F.  WEINBROT. 


FROSTING  GLASS  WITH  BEER. 

Secure  y2  pint  of  lager  (light  or  dark) 
beer,  and  to  this  add  enough  epsom  salts, 
so  that  when  stirred  up  it  will  be  the  con- 
sistency of  cream.  Apply  this  cream  to  the 
glass  to  be  frosted  with  a  sponge.  This 
frosting  will  not  readily  wear  or  rub  off  un- 
der any  conditions. 

Contributed  by  EUGENE  RUCKMAN. 


42 


THE  ELECTRICAL  EXPERIMENTER 


May,  1917 


HOW  TO  KNOW  WHEN  TOOLS 
ARE  RETURNED. 

Every  experimenter  knows  that  people 
who  come  in  and  borrow  tools  never,  by 


To  Tell  at  a  Glance  Whether  or  Not  a  Cer- 
tain Tool  Has  Been  Returned,  Simply  Paint 
Its  Outline  in   Black  or  White  on  a  White 
or  Black   Board  as  Shown. 


any  chance,  replace  them  in  their  proper 
place. 

The  accompanying  illustration  shows  a 
very  simple  method  of  overcoming  this  an- 
noyance. The  outlines  of  the  tools  are 
painted  in  white  or  black  on  the  cabinet 
wall  in  the  positions  which  the  tools  nor- 
mally occupy.  When  this  is  done  a  person 
has  only  to  glance  at  the  cabinet  and  can 
tell  immediately  just  where  each  tool  be- 
longs. 

Contributed  by 

AN  EXPERIMENTER. 


A  SOUND  OPERATED  MOTOR. 

Take  any  telephone  transmitter  and  re- 
move the  carbon  granule  cup,  solder  a  plat- 
inum point  to  any  metal  piece  and  fasten 
in  place  of  the  granule  cup.  Solder  a  plat- 
inum point  to  the  center  of  the  diafram. 
The  two  platinum  points  should  be  as  near 
each  other  as  possible  without  touching. 
The  battery  motor  is  equipt  with  a  wood- 
en block  fastened  to  the  axle  shaft.  A 
mirror  can  be  fastened  on  either  side  of 
the  block.  A  beam  of  light  can  thus  be 
reflected,  which  should  prove  interesting 
to  those  experimenting  with  sound  waves. 
The  motor  and  transmitter  are  placed  in  a 
circuit  with  a  battery. 

Any  word  spoken  into  the  transmitter 


D/ophrogm 
( 


Baft 

Ptot/numJ  iiyj|  \^ 
points 


Mirror 


Novel    Scheme    for    Controlling  Revolving 
Mirror  by  Means  of  a  Microphone. 

will  vibrate  the  diaphragm,  and  cause  the 
motor  to  spin  around  at  different  speeds, 
according  to  the  words  spoken. 


PRACTICAL  HELPS  FOR  THE 
AMATEUR. 

Repairing  Dry  Cell  Terminals. — A  simple 
method  is  to  solder  a  6-inch  length  of  flex- 
ible wire  to  the  zinc  container  of  the  dry 
cell  for  making  connections.  If  a  binding 
post  is  necessary,  solder  a  spring  binding 
post  in  place  as  shown.  In  emergencies 
paper  clips  may  be  used,  bending  as  shown 
and  slipping  wire  into  them. 

Shocking  Machine  from  Alarm  Clock. — 
Since  a  clock  is  generally  used  as  an  in- 
terrupter best  results  can  be  obtained  by 
arranging  a  spring  to  press  against  one 
of  the  wheels  which  revolve  at  fairly  high 
speed,  when  the  balance  wheel  is  removed. 
A  higher  rate  of  interruption  results,  giv- 
ing a  constant  tingle  instead  of  a  series  of 
jerks.  The  spring  and  gear  are  connected 
in  series  with  two  handles,  an  electromag- 
net and  two  to  three  dry  cells. 

Simple  Time  Signal. — The  relay  and  re- 
sistance shown  in  a  previous  issue  of  this 
journal  may  be  done  away  with  by  simply 
rewiring  the  time  ball  solenoid  and  horn  as 
shown  herewith.  This  likewise  does  away 
with  an  extra  set  of  batteries.  Key  B 
operates  the  electric  horn  and  A  controls 
the  semaphone. 

Removing  Enamel  from  Magnet  Wire. — 
The  easiest  method  is  to  use  an  ink  eraser 
for  this  purpose.  The  wire  is  cleaned 
quickly  and  perfectly  without  excessive 
abrasion.  To  do  this  easily,  slit  one  end 
of  the  eraser  and  run  the  wire  thru  the 
slit  several  times. 

Fuse  Clips. — This  fuse  is  in  the  same 
class  as  the  above  hints,  being  made  from 


Contributed  by 


LEE  A.  COLLIXS. 


Some  Handy  Kinks  for  the  Experimenter. 


paper  clips.  Fasten  to  board  with  screws 
or  tacks  and  slip  fuse  wire,  fine  copper 
wire  or  tinfoil  under  clip. 

Contributed  by  T.  W.  BEN  SOX. 

A  CLEVER  USE  FOR  SPEED  INDI- 
CATORS. 

In  constructing  a  metal  pattern  recently 
in  order  to  determine  the  amount  of  metal 
needed  for  a  wall,  it  became  necessary  to 
find  the  perimeter  of  a  figure  similar  to 
that  shown  in  Fig.  1.  The  work  was  held 
up  until  a  way  of  doing  this  could  be  found. 
I  at  last  thought  of  the  following  device  : 

A  brass  wheel.  -)4  inches  in  diameter,  was 
soldered  on  the  shaft  of  an_  "Electro" 
Speed  Counter  as  shown  in  Fig.  2.  The 
counter  was  then  grasped  in  the  hand  and 
the  wheel  was  run  around  the  edge  of  the 
design.  The  diameter  of  the  wheel  was 
multiplied  by  3.1416  to  obtain  the  circum- 
ference of  the  wheel,  which  was  then  mul- 
tiplied by  the  revolutions  shown  on  the  in- 
dicator. This  gave  the  distance  around  the 
figure.  The  size  of  the  wheel  can  of  course 
be  altered  to  suit  different  conditions. 

Contributed  by       J.  C.  GILLILAND. 

[Editorial  Note: — Another  useful  dodge 


A  HANDY  HEIGHT  GAGE. 

The  sketch  gives  dimensions  for  making 
this  useful  height  gage.  The  micrometer 
head  is  of  Brown  &  Sharpe  make  and  will 
give  a  forced  fit  in  the  .374"  hole.  It  will 
be  necessary  to  anneal  the  spindle  end  to 
tap  a  No.  3-48  thread,  so  as  to  hold  the 


An  Effective  Precision  Height  Gage  May  Be 
Constructed    from    a    Standard  Micrometer 
Head  Fitted  in  a  Steel  Base  of  the  Dimen- 
sions Indicated. 

linger  shown  in  detail  at  the  right,  also 
the  screw.  The  bottom  surface  of  the  base 
is  undercut  1/16  leaving  a  3/16  foot  all 
around. 

Harden  the  finger,  screw  and  base,  and 
when  finger  is  attached  to  spindle  it  is 
moved  all  the  way  to  zero  on  barrel ;  that 
is,  when  tapping,  base  and  finger  are  to- 
gether, the  micrometer  head  is  set  at  zero, 
all  moving  parts  having  a  free  sliding  fit 
with  no  shake. 

This  gage  has  one  advantage  over  the 
great  number  of  other  height  gages  in  that 
you  can  scratch  a  line  from  O  to  any  rea- 
sonable dimension. 

Contributed  by    JAMES  McIXTYRE. 

ill  this  direction  consists  of  making  a  brass 
wheel  as  shown  at  Fig.  3,  having  a  small 
groove  in  its  perifcry;  in  this  groove  is 
placed  (glued)  a  rubber  band  which  is 
slightly  smaller  than  the  wheel.  Knowing 
the  dimensions  of  this  wheel  and  noting 
the  revolutions  on  the  dial,  it  becomes  an 
easy  matter  to  measure  railroad  lines,  state 
border  lines,  conduit  and  pipe  runs  on  blue- 
prints, ct  cetera,  by  simply  rolling  the 
wheel  along  these  lines.  In  one  of  these 
devices  which  we  used  some  time  ago,  the 
wheel  was  made  so  as  to  have  a  circum- 
ference of  5  inches,  or  a  maximum  diame- 
ter of  about  1%  inches.  The  diameter 
multiplied  by  3.1416,  gives  the  circumfer- 


15  9  7 


F/g.Z 


Brass  wtiee/ 

for 

rudder  band 

rMber 


Bore  to  f ft 
shaft fgfrf/t/ 


fig.  3 


Attachment  for  a  Speed  Indicator  Making  It 
Available   for    Measuring    the    Perimeter  of 
Irregular  Surfaces,  Map  Routes,  etc. 

ence  and  the  latter  term,  divided  by  3.14161 
gives  us  the  diameter.] 


May,  1917 


THE  ELECTRICAL  EXPERIMENTER 


43 


Experimental  Chemistry 

By  ALBERT  W.  WILSDON 
Twelfth  Lesson 


ACIDS,  BASES,  AND  SALTS. 

IN  this  lesson  we  shall  take  up  the 
study  of  the  various  acids  and  char- 
acteristics. These  form  one  of  the 
most  important  studies  in  the  realm 
of  chemistry.  A  resume  of  the  gen- 
eral properties  of  acids  are  briefly  as  fol- 
lows : 


How  Apparatus  Is  Arranged  in  Experiment  of 
Collecting  the  Product  of  Acetic  Acid. 


1.  An  acid  is  a  substance  composed  of 
hydrogen  and  a  non-metallic  element  or 
radical,  the  hydrogen  being  replaceable  by 
a  metal  or  a  group  of  elements  equivalent 
to  a  metal.  The  fact  that  hydrogen  is  a 
constituent  of  all  acids,  explains  why  they 
are  sometimes  called  Salts  of  Hydrogen. 

2.  Acids  usually  have  a  sour  taste. 

3.  Tf  soluble  in  water,  as  most  acids  are, 
they  turn  blue  litmus  paper  (or  solution) 
red.  They  also  change  the  color  of  man} 
vegetable  substances. 

4.  They  react  readily  with  a  base  to 
form  a  salt  and  water. 

5.  They  react  readily  with  some  metals 
to  form  salts,  liberating  hydrogen. 

6.  Most  acids  are  soluble  in  water. 

7.  They  also  have  the  power  to  decom- 
pose most  carbonates,  like  limestone,  lib- 
erating carbon  dioxid  which  escapes  with 
effervescence. 

The  common  acids  are: 
Hydrochloric    (HC1):    Xitric    (HX03)  ; 
Sulfuric  (H..SCM;  Acetic  (C2H4OJ  ;  Ox- 
alic (H2C204)  ;  Tartaric  (H2C4H„04)  and 
Citric  (C6H80t); 

Of  these  common  acids,  Hydrochloric  is 
a  gas  (the  Hydrochloric  or  Muriatic  acid 
of  commerce  is  only  the  gaseous  acid  in 
solution)  :  Sulfuric  and  Nitric  acids  are 
liquids :  while  Oxalic,  Tartaric,  and  Citric 
acids  are  solids. 

To  illustrate  the  many  familiar  sub- 
stances which  are  acids  or  contain  them, 
we  will  take  the  following  few : 

Vinegar,  Pickles  and  Relishes,  when  Ace- 
tic acid  is  present,  attributes  to  the  agree- 
able sour  taste. 

Vinegar  is  simply  a  dilute  solution  of 
acetic  acid,  containing  coloring  matter  and 
other  substances,  obtained  by  the  acetus 
fermentation  of  poor  wine  or  wine  resi- 
dues, of  beer  which  has  turned  sour,  and 
of  other  dilute  alcoholic  liquids. 

The  sourness  of  fruits  being  due  to  the 
presence  of  citric  acid,  as  in  the  lemon, 
rpnle,  currant,  r  spberry,  gooseberry,  etc. 

During  fermentation  many  acids  are 
formed,  as  in  the  case  of  sour  milk,  lac- 
tic acid  is  present 


Soda  water  is  a  solution  of  Carbonic 
acid  (Carbon  Dioxid),  and  acid  phosphate 
is  a  solution  of  a  sour  calcium  phosphate. 
.Mineral  waters  frequently  contain  Car- 
bonic acid. 

Hydrochloric  acid  is  present  in  the  gas- 
tric juice  of  the  stomach,  and  performs 
an  important  part  in  the  process  of  diges- 
tion. 

From  the  above  we  can  see  that  many 
acids  are  of  importance,  and  many  are 
used  by  us  every  day  in  some  form  or 
other.  We  can,  therefore,  see  that  all 
acids  are  not  to  be  scorned  as  danger- 
ous, as  doubtless  many  readers  of  this  ar- 
ticle have  heretofore  believed,  when  the 
word  acid  was  mentioned. 

NOMENCLATURE  OF  ACIDS— 

Oxygen  is  a  component  of  most  acids, 
and  the  names  o!  these  acids  correspond  to 
the  proportion  of  oxygen  which  they  con- 
tain. The  best-known  acid  of  an  element 
usually  has  the  suffix  -ic,  as  Sulfuric,  Nit- 
ric, Phosphoric.  If  an  element  forms  an- 
other acid  containing  less  oxygen,  this  acid 
has  the  suffix  -ous,  as,  Sulfurous,  Chlorous, 
Phosphorous.  Some  elements  form  an  acid 
containing  less  oxygen  than  the  -ous  acid; 
these  acids  retain  the  suffix  -ous,  and 
have,  also,  the  prefix  Hypo-,  as,  Hyposul- 
furous,  Hypophosphorous,  Hypochlorous. 
The  prefix  Hypo-  is  derived  from  the 
Greek  word,  meaning  lesser  or  under.  If 
an  element  forms  an  acid  containing  more 
oxygen  than  an  -ic  acid,  such  an  acid  re- 
tains the  suffix  -ic  and  has,  also,  the  pre- 


ln  Conducting  Experiments  With  Various 
Acids  it  Will  be  Found  Convenient  to  Place 
the  Test  Tubes  Containing  the  Acids  in  a 
Wooden  Rack.  The  Tubes  May  Be  Suitably 
Labeled. 


fix  Per,  as,  Persulfuric,  Perchloric.  The 
Latin  prefix  meaning  beyond  or  over.  The 
few  acids  which  contain  no  oxygen  have 
the  prefix  Hydro-  and  the  suffix  -ic,  as, 
Hydrochloric,  Hydrobromic,  Hydrofluoric. 
It  should  be  noticed  that  these  suffixes  are 
not  always  added  to  the  name  of  the  ele- 
ment, but  often  to  some  modification  of  it. 

Acids  having  the  prefix  Hydro-  and  end- 
ing in  -ic  form  salts  with  names  ending  in 
-ide  and  having  no  prefix. 

All  other  acids  with  names  ending  in  -ic 
form  salts  with  names  ending  in  -ate. 
[Final  "e"  dropt  in  simplified  spelling.] 

All  acids  who.e  names  end  in  -ous,  form 
salts. whose  names  end  in  -ite. 

ACIDS   AND   THEIR  SALTS. 

Hydrochloric  acid.  HC1;  Form  Chlorids,  NaCl; 
Sodium  Chlorid. 
Sulfuric  acid.  H?SO<<;  Form  Sulphats,  CUSO4; 

Coiper  Sulphat. 
Nitric  acid,  HNOj;  Form  Nitrats  Pb[N03]2; 
lead  Kitrat. 
Sulfurous  acid,  H^SO^;  Form  Sulphits,  K2SO3; 

Potassium  Sulphit. 
Hydrobromic  acid,  HBr:  Form  Bromide,  AgEr; 

Silver  Bromid. 
Carbonic  acid,  H2CO3;  Form  Carbonats  CaCO^; 
Calcium  Carbonat. 
Hydrosulfuric  acid.  H3S:  Sulphids,  ZnS; 
Zinc  Sulphid. 


Hydroiodic  acid,  HI;  Form  Iodids,  Kl  ;Potassium  lodid 
Nitrous  acid.  HNO2;  Nitrits,  NaNCb; 
Sodium  Nitrit. 
Phosphoric  acid,  H3PO4;  Form  Phosphats,  FePCj; 
Iron  Phosphat. 
Hydrofluoric  acid,  HF;   Form  Fluorids,  CaF2; 

Calcium  Fluorid. 
Chloric  acid,  HCIO3;   Form  Chlorats,  KCIO3; 
Potassium  Chlorat. 

The  nomenclature  of  acid,  is  well  illu  - 
trated  by  the  scries  of  chlorin  acids: 


Name.  Formula. 

Hydrochloric  HC1 

Hypochlorous  HCIO 

Chlorous  '.   HCIO2 

Chloric  HCIO3 

Perchloric  HCIO4 


Not  all  elements  form  a  comp'.ete  series 
of  acids,  but  the  nomenclature  usually 
agrees  with  the  above  principles. 

An  examination  of  the  formulas  of  acids 
show  that  all  do  not  contain  the  same  num- 
ber of  hydrogen  atoms.  Acids  are  some- 
times classified  by  the  number  of  hydro- 
gen ;>toms  which  can  be  replaced  by  a 
metal.  The  varying  power  of  replaceability 
is  called  Basicity.  A  Monobasic  Acid  con- 
tains only  one  atom  of  replaceable  hydro- 
gen in  a  molecule,  as  Xitric  Acid  HXO. 
A  molecule  of  Acetic  acid  (C2H402)  con- 
tains four  atoms  of  hydrogen,  but  for  rea- 
sons which  are  too  complex  to  state  here, 
only  one  of  these  atoms  can  be  replaced  by 
a  metal.  Dibasic  and  Tribasic  Acids  con- 
tain two  and  three  replaceable  atoms,  as, 
Sulfuric  acid  (H2SOi)  and  Phosphoric 
acid  (H,POi  ).  Obviously,  monobasic  acids 
form  only  one  class  of  salts,  dibasic  acids 
form  two  classes,  tribasic  acids  form  three, 
etc. 

EXPERIMEXT  XO.  51 

Fill  a  test  tube  one-third  full  of  either 
Hydrochloric  Acid  (diluted),  or  Sulfuric 
Acid  (diluted).  Fill  another  test  tube  one- 
third  full  of  concentrated  acetic  acid.  In 
some  manner  label  the  tubes  for  identifica- 
tion of  the  contents. 

Try  the  action  of  a  drop  of  the  acid  on 
both  red  and  blue  litmus  paper. 

Drop  a  small  piece  of  zinc  or  other  metal 
into  each  tube  successively.  If  no  chemi- 
cal action  results,  warm  gently.  Test  for 
the  most  obvious  product  (hydrogen)  by 
holding  a  lighted  match  at  the  mouth  of 
each  tube.  If  no  decisive  action  results, 
provide  the  test  tube  with  a  stopper  and 
simple  delivery  tube,  and  collect  any  pro- 
duct in  a  test  tube  over  water.    This  lat- 


Simple  Method  of  Dropping  Liquids  by  Means 
of  a  G  ass  Rod  Held  in  the  Hand. 


ter  method  will  probably  be  unnecessary 
except  with  the  acetic  acid. 

(Continued  on  page  52") 


44 


THE  ELECTRICAL  EXPERIMENTER 


May,  1917 


Under  this  heading  we  publish  every  month  use- 
ful information  in  Mechanics,  Electricity  and 
Chemistry.  t  We  shall  be  pleased,  of  course,  to 
have  our  readers  send  us  any  recipes,  formulas, 
wrinkles,  new  ideas,  etc.,  useful  to  the  experi- 
menter, which  will  be  duly  paid  for,  upon  pub- 
lication,  if  acceptable.  


EXPERIMENTER'S  APHORISMS 
In   the   following,    we   wish    to   give   to  the 
Experimenter  some  hints  as  to  the  use  of  the 
different  ingredients  and   how  to  work  them: 

(1)  Always  bear  in  mind  that  exact  working 
of  a  formula  requires  ACCURACY,  CLEANLI- 
NESS, PATIENCE,  and  SKILL. 

(2)  Know  what  you  are  about,  before  you  start 
to  experiment. 

(3)  "THE  HISTORY  OF  FAILURES  IS  THE 
HISTORY  OF  SUCCESS"  goes  an  old  adage,  and 
it  applies  well  to  the  experimenter. 

(4)  Many  times  impure,  wrong  or  deteriorated 
raw  materials,  spell  FAILURE  instead  of  SUC- 
CESS. 

(5)  A  great  many  of  the  chemicals  and  in- 
gredients requited,  cannot  be  obtained  from 
drug  stores;  buy  them  at  a  reputable  supply 
house. 

(6)  BEFORE  CONDEMNING  A  FORMULA,  be 
sure  the  fault  does  not  lie  with  the  manner  of 
handling  it,  or  the  purity  of  the  ingredients. 

(7)  Be  sure  to  mix  the  materials  comprising 
a  certain  formula  in  the  proper  sequence. 

(8)  When  starting  to  prepare  a  mixture, 
especially  one  containing  liquids,  ask  yourself: 
"IS  THE  SPECIFIC  GRAVITY  CORRECT,  AS 
INDICATED  BY  A  HYDROMETER?  IS  THE 
TEMPERATURE  RIGHT?  IS  THE  QUANTITY 
OR  WEIGHT  RIGHT? 

(9)  Acids  and  water,  when  mixed,  should  be 
manipulated  in  the  proper  manner,  i.  e.,  THE 
ACID  SHOULD  BE  POURED  INTO  THE 
WATER,  and  not  vice  versa,  as  the  solution  is 
liable  to  be  forcibly  ejected  from  the  containing 
vessel  and  into  the  mixer's  face. 

(10)  For  any  kind  of  SYSTEMATIC  WORK, 
a  floating  THERMOMETER  and  HYDROM- 
ETER, as  well  as  measuring  glasses  and 
scales,  should  always  be  provided,  as  GUESS- 
WORK is  EXPENSIVE,  and  SOMETIMES 
FATAL. 

(11)  Put  labels  on  ALL  bottles,  boxes  and 
packages  with  FULL  INSCRIPTION  as  to  their 
contents,  it  will  avoid  troubles  and  mistakes. 

(12)  Remember  that  a  beginner  cannot  expect 
to  make  articles  AT  FIRST,  which  will  com- 
pare with  regular  manufactured  products.  S.G 


CHEMICAL  EXPERIMENTS. 

I  have  been  experimenting  a  little  and 
have  found  that  an  infusion  of  logwood 
chips  and  water  will  change  color  when 
other  chemicals  are  added. 

Take  three  glasses  Xos.  1,  2  and  3  and 
prepare  them  as  follows :  Rinse  Xo.  1 
with  strong  vinegar ;  Dust  Xo.  2  with 
powdered  alum ;  Rinse  Xo.  3  with  a  solu- 
tion of  copper  sulfate.  The  next  step  is 
to  pour  the  logwood  into  each.  If  the 
glasses  have  been  prepared  correctly  the 
logwood  in  Xo.  1  will  fade  to  a  pale  yel- 
low. That  in  Xo.  2  will  become  almost 
black  and  that  in  Xo.  3  will  change  to  a 
pale  purple.  This  is  the  principal  set  of 
changes  but  following  is  a  list  of  changes 
using  not  only  logwood  but  also  other 
chemicals.  Some  of  them  can  be  used  as 
stated  above  but  in  the  case  of  ammonia 
for  instance,  the  odor  would  give  it  away. 

Color  changes  that  are  due  to  chemi- 
cal action : 

1.  — Logwood,  ammonia  and  copper  sulfate 
gives  a  brown. 

2.  — Logwood,  vinegar  and  ammonia  gives 
purple. 


3.  — Logwood,  alum  and  ammonia  cause 
a  red  precipitate. 

4.  — Logwood,  vinegar  and  copper  sulfate 
gives  a  brown. 

5.  — Logwood,  ammonia  and  common  salt 
gives  a  light  brown. 

6.  — Logwood,  copper  sulfate,  common 
salt,  and  alum  mixed  give  a  pink. 

7.  — Phenolphthalein  and  ammonia  gives 
a  bright  red  (test  for  free  ammonia). 

8.  — Copper  sulfate  and  ammonia  gives  a 
bright  blue  (test  for  copper  sulfate). 

9.  — Logwood  and  hydrogen  peroxid  gives 
a  pale  yellow. 

10.  — Logwood,  copper  sulfate  and  caustic 
soda  gives  a  pale  blue  precipitate. 

These  are  the  results  as  far  as  I  have 
gone  but  I  hope  to  continue  my  work  and 
get  different  results. 

Contributed  by        W.  B.  SPURRIER. 


HANDY  APPARATUS  FORMED 
ENTIRELY  OF  WIRE. 

As  shown  in  the  accompanying  sketches 
a  number  of  useful  articles  of  constant 
service  to  the  experimenter  may  be  con- 
structed of  ordinary  wire  with  the  aid  of  a 
few  common  tools. 

Obtain  a  few  feet  of  galvanized  iron  wire, 
or  if  the  item  of  expense  is  not  important, 
brass  wire ;  3  or  4  gage  numbers  are  re- 
quired, depending  upon  the  size  of  the 
apparatus  to  be  constructed. 

Provide  a  pair  each  of  flat,  round  and 
cutting  pliers,  some  wood  sticks  about  the 
dimensions  of  a  lead  pencil,  and  a  few 


Numerous  Handy  Devices  for  Holding  Test 
Tubes  and  the  Like  Can  be  Easily  Con- 
structed from  Wire  with  a  Little  Ingenuity. 

short  lengths  of  tubing  to  aid  in  bending 
and  forming  the  wire;  after  a  few  ex- 
periments you  will  be  able  to  determine 
the  size  of  the  wire  best  adapted. 
Cork  Puller. 
Figure  1. — Cut  two  pieces  of  wire  the 
desired  length,  twist  together  and  form 
ring.  Xow  twist  the  four  ends  to  about 
one-third  the  length  of  the  shank.  Make 
separately  a  ring  of  sufficient  size  to  fit 
loosely  over  the  shank,  cut  wires  of  shank 
to  same  length  and  bend  ends  to  a  right 
angle  about  %  inch.  Slip  on  the  ring 
and  spring  the  four  ends  apart  to  keep 
ring  in  position.  The  completed  article 
will  be  found  of  service  in  removing  corks 
which  have  fallen  into  the  container,  and 
by  placing  a  piece  of  cotton  in  the  jaws  a 
most'  useful  instrument  is  formed  for  the 
cleaning  and  drying  of  test  tubes. 

Holders. 

Figures  2  and  3. — Follow  outline  of 
sketch  to  obtain  good  results.  Twist  wires 
together  3  or  4  times,  allowing  but  very 
little  play.  Bend  the  four  ends  at  a  straight 
angle  and  form  the  ring  at  the  end  of  tool 
by  bending  wire  around  a  rod  of  the  re- 
quired size. 


CHEMICAL  SUBSTANCES  — THEIR 
TECHNICAL  AND  COMMON 
NAMES. 

Xearly  all  of  the  chemicals  in  common 
use  to-day  have  more  than  one  name,  and 
the  purpose  of  this  list  is  to  classify  some 
of  the  most  common  ones  in  use  for  the 
benefit  of  the  amateurs  who  sometimes  be- 
come confused  in  the  different  names.  The 

Aqua  Fortis  Nitric  Acid. 

Aqua  Regia  Nitro-Muriatic  Acid  or  Nitro- 

Hydrochloric  Acid. 

Blue  Vitriol  Sulfat  of  Copper. 

Cream  ol  Tartar  Tartrate  of  Potassium. 

Calomel  Sub-Chloride  of  Mercury. 

Chalk  Calcium  Carbonate. 

Salt  ot  Tartar  Carbonate  of  Potassium. 

Caustic  Potassa  Hydrate  Potassium. 

Chloroform  Chlorid  of  Formyle. 

Common  Salt  Chlorid  ot  Sodium. 

Copperas,  or  Green  Vitriol. .  .Sulfate  ot  Iron. 

Corrosive  Sublimate  Bi-Chlorid  of  Mercury. 

Dry  Alum  Sulfate  Aluminum  and  Potas- 
sium. 

Epsom  Salts  Sulfate  of  Magnesium. 

Ethiop's  Mineral  Black  Sulfid  of  Mercury. 

Galena  Sulfid  of  Lead. 

Glauber's  Salts  Suhate  of  Sodium. 

Iron  Pyrites  Bi-Sulfid  of  Iron. 

Jewelers  Putty  Oxid  of  Tin. 

Kings  Yellow  The  Sulfid  of  Arsenic. 

Laughing  Gas  Protoxid  of  Nitrogen. 

Lime   .  .Oxid  of  Calcium. 

Lunar  Caustic  Nitrate  of  Silver. 

Muriate  of  Lime  Chlorid  of  Calcium. 

Niter  of  Saltpeter  Nitrate  of  Potash  or  Potas- 
sium Nitrate. 

Oil  of  Vitriol  Sulfuric  Acid. 

Realgar  Bi-Sulfid  of  Arsenic. 

Red  Lead  Lead  Oxid. 

Rust  ot  Iron  Iron  Oxid. 

Sal-Ammoniac  Muriate  of  Ammonia. 

Slacked  Lime  Hydrate  Calcium. 

Soda  Oxid  of  Sodium. 

Spirits  01  Hartshorn  Sesquicarbonate    of  Ammo- 

ium. 

Spirits  of  Salt  Hydrochloric     or  Muriatic 

Acid. 

Stucco  of  Plaster  of  Paris ...  .  Sulfate  of  Lime. 

Sugar  of  Lead  Acetate  -of  Lead. 

Verdigris  Acetate  of  Copper. 

Vermillion  Sulfid  of  Mercury. 

Vinegar  Acetic  Acid  (dilute). 

Volatile  Alkali  Ammonia. 

Water  Sub-Oxide  of  Hydrogen. 

White  Vitriol  Sulfate  of  Zinc. 

chemicals  in  the  two  lists  opposite  each 
other  are  the  same  under  a  different  name. 
Contributed  by        EARL  BOTTEN. 


Spring  Holders. 

Figures  4  and  5. — Use  very  thick  and 
springy  wire;  will  be  found  of  service  in 
holding  articles  to  be  soldered  or  ce- 
mented. It  will  be  observed  from  sketch 
that  device  in  figure  Xo.  4  holds  by  itself, 
while  the  reverse  is  true  of  Xo.  5  design. 
The  ends  of  these  holders  can  be  made 
pointed  or  flattened  as  preferred. 

Figure  6. — Holder  for  rubber  tubes.  Ob- 
tain a  piece  of  thin  wire.  First  bend  it  in 
two,  making  a  loop  to  allow  a  hook  to 
hold  it  in  place.  Then  wind  wire  around 
a  rod  of  proper  size.  Slip  tube  thru  spiral 
so  formed.  This  device  will  not  permit 
tube  to  kink  or  bend  at  an  angle  sufficient 
to  kink  or  to  fracture. 

Figure  7. — Holder  for  articles  to  be  sol- 
dered or  heated.  The  slight  pressure  ob- 
tained by  allowing  the  straight  bend  to 
pass  a  little  thru  the  ring  will  be  found 
sufficient  to  hold  the  articles  in  a  position 
convenient  for  operation. 

Figure  8. — Tripod  to  support  retorts. 
This  article  is  formed  by  twisting  three 
wires  together  forming  a  stand  as  shown 
in  sketch. 

Figure  9,  10  and  11.— Battery  connectors. 
Figure  10  can  be  fastened  to  table  by  put- 
ting a  screw  or  nail  thru  ring  at  its 
end.  In  the  event  of  the  contact  jaws 
becoming  loose  they  can  be  adjusted  by 
drawing  the  ends  closer  together.  The 
line  wires  can  be  soldered  to  the  connec- 
tors, and  if  desired  the  connection  on 
figure  11  can  be  covered  with  insulating 
tape. 

Figure  12. — Very  light  weights.  Each 
bend  increases  1  centigram  or  1  decigram,, 
varying  according  to  the  size  of  wire  used. 

Contributed  by 

AX  EXPERIMEXTER. 


May,  1917 


THE  ELECTRICAL  EXPERIMENTER 


45 


Our  Amateur  Radio  Station  Contest  is  open  to  all  readers,  whether  subscribers  or  not.  The  photos  are  judged  for  best  arrangement  and  efficiency 
of  the  apparatus.  To  increase  the  interest  of  this  department  we  make  it  a  rule  not  to  publish  photos  of  stations  unaccompanied  by  that  of  the  owner.  Dar.jc 
photos  preferred  to  light  toned  ones.  We  pay  each  month  $3,00  prize  for  the  best  photo.  Make  your  description  brief  and  use  only  one  side  of  the  sheet. 
Address  the  Editor,  "With  the  Amateurs"  Dept. 


AMATEUR  RADIO  STATION 
CONTEST. 
Monthly  Prize,  $3.00. 
This  month's  prize-winner. 

RADIO  STATION  OF  FRED  DIETZ, 
PHILADELPHIA,  PA. 

I  present  here  a  flashlight  photo  of  my 
station.  The  aerial  is  forty  feet  high,  one 
hundred  feet  long,  composed  of  three  wires 
spaced  six  feet  apart. 


Long  Wave  Radio  Station  of  This  Month's 
Prize  Winner — Mr.   Fred   Dietz,  of  Philadel- 
phia,  Pa.     He   Hears  the  German  Stations 
and  Many  Others. 

The  sending  set  consists  of  a  V/2  inch 
Manhattan  spark  coil,  Murdock  sending 
condenser,  spark  gap  and  key.  I  also  have 
a  six  volt  storage  battery,  and  can  send 
fifteen  miles. 

The  receiving  set  consists  of  two  loose 
couplers,  one  tunes  up  to  two  thousand  me- 
ters and  the  other  to  three  thousand  meters. 
The  small  loose  coupler  is  used  with  a  crys- 
tal detector.  The  large  loose  coupler  is 
used  on  the  Audion  and  Audio-tron.  I  use 
three  Bunnell  variable  condensers,  three 
loading  coils  and  a  pair  of  Murdock 
'phones.  I  can  hear  OUI,  POZ,  NBA 
(Darien,  Panama),  NAT  (New  Orleans), 
NAR  (Key  West  J  ;  and  a  great  many  other 
land  and  ship  stations,  on  undamped  waves. 
I  can  hear  as  far  as  Key  West  on  a  crys- 
tal detector.    My  call  number  is  3GA. 

Philadelphia,  Pa.  FRED  DIETZ. 


THE  FIRST  "RADIO"  MESSAGES. 

At  the  battle  of  Ishtib  a  Bulgarian  cow- 
herd signaled  news  to  his  military  coun- 
trymen relative  to  the  position  of  the  Ser- 
bian battalions  by  moving  five  cows  about 
in  various  ways  on  the  top  of  a  hill. 

The  Basutos,  by  the  way,  practically  an- 
ticipated "wireless  telegraphy"  in  a  crude 
fashion.  That  is,  by  striking  heavily  on  a 
huge  drum  of  goat  skin,  which  is  placed 
on  a  special  spot,  another  Basuto  at  a  dis- 
tance can  gather  the  purport  of  the  mes- 
sage by  placing  his  ear  close  to  the  ground 
to  catch  the  vibrations,  and  he  in  turn 
passes  the  message  on. 

Of  course,  given  suitable  climatic  condi- 
tions, the  military  heliograph  can  transmit 
messages  over  enormous  tracts  of  coun- 
try, and  the  record  is  probably  held  by  an 
Englishman,  Captain  Sadler,  of  the  Sixth 
Dragoon  Guards,  who,  by  this  means,  suc- 
ceeded in  South  Africa  in  sending  a  mes- 
sage direct  a  distance  of  130  miles. 


WALTER   LITRE'S  EFFICIENT 
RADIO  STATION. 

I  have  been  reading  your  valuable  maga- 
zine for  the  past  two  years,  and  have  been 
greatly  interested  in  the  photos  of  ama- 
teur stations  which  you  publish  monthly.  I 
submit  two  photos,  one  of  my  station  and 
one  of  my  aerial.  My  sending  set  consists 
of  an  E.  I.  Co.'s  Vi  k.w.  transformer,  a 
Murdock  oscillation  transformer,  a  Mar- 
coni key,  straight  spark  gap,  a  photographic 
plate  condenser  consisting  of  ten  plates,  8 
by  10  inches,  with  tin-foil  between  cut  6  by 
8  inches. 

The  receiving  set  consists  of  an  Arnold 
Navy  type  loose  coupler  of  2,500  meters, 
Holtzer-Cabot  3,000  ohm  'phones,  Clapp 
Eastham  fixt  condenser,  Alurdock  variable 
condenser,  Bunnell  detector,  and  an  aerial 
switch.  My  aerial  is  made  of  seven  strand 
copper  wire  with  a  twenty  foot- mast  at  one 
end  and  a  thirty  foot  one  at  the  other.  The 


aerial  is  75  feet  long.  I  have  not  received 
my  official  call  from  the  Government  yet, 
but  have  my  application  in. 

WALTER  E.  LITKE. 

Fordham,  N.Y. 


ELECTRIC  HAND  GENERATOR 
DETONATES  DYNAMITE. 

An  electric  generator  small  enough  to 
be  carried  in  a  man's  pocket,  yet  powerful 
enough  to  discharge  dynamite  blasts,  has 
been  invented. 


[1             ATTENTION!!!  [I 

||    Has  your  station  photo  appeared  in  II 

||    "The  Electrical  Experimenter"?  Why  || 

||    not  purchase  the  electrotype  and  have  || 

||    some  "real"  stationery  printed  with  II 

||  youi  station  picture  on  it?  All  of  the  || 
||    "regular  radio-bugs"  are  doing  it. 

^  """  ""•  ,,,,!!!!!!!, ,!!ii!!!!!!!!!m!!!!!!!l!!!!'!!!lml!!!,„Mi,„„uS 


RADIO   JOINS   SAMOAN  ISLANDS 
WITH   UNITED  STATES. 

Construction  of  another  government 
wireless  plant,  connecting  the  United 
States  with  its  insular  possessions,  has 
been  completed  at  Tutuila,  placing  the 
Samoan  Islands  in  direct  communica- 
tion with  the  outside  world  for  the  first 
time  since  their  acquisition  by  the  U.S. 

The  station  at  Tutui! .  connects  with 
Honolulu,  where  a  great  plant  commu- 
nicates with  San  Diego,  Cal.  Governor 
Poyer,  of  the  Islands  retired  naval  offi- 
cer, advised  Secretary  Daniels  on  Feb- 
ruary seventeenth  of  the  completion  of 
the  plant  and  transmitted  a  message 
from  the  native  chiefs. 


LEONARD  NIESSEN  A  COMING 
"RADIO-BUG." 

The  sending  set  consists  of  a  one-half 
inch  spark  coil,  plate  and  Leyden  jar  con- 
denser, oscillation  transformer,  spark  gap 
and  key. 

The  receiving  set  consists  of  a  Murdock 
loose  coupler,  fixt  condenser,  galena  and 
silicon  detectors,  Brandes'  2,000  and  E.  I. 
Co.'s  2,000  ohm  'phones  and  a  buzzer  test. 

The  vertical  rod  seen  under  the  center  of 
the  table  is  an  automatic  closing  lightning 
switch,  operated  by  a  foot  lever,  the  switch 
itself  being  outside  on  the  wall  of  the 
house.  Most  of  the  apparatus  is  of  my 
own  construction.  The  aerial  consists  of 
six  wires  spaced  two  feet  apart  on  twelve 
feet  spreaders,  fifty  feet  long  and  forty 
feet  high. 

I  am  a  member  of  the  Milwaukee  Radio 
Association,  also  the  Central  Radio  Asso- 
ciation and  hold  a  first  grade  Amateur  Li- 
cense.   Call  "9AKC."  . 

Have  been  a  subscriber  to  The  Elec- 


trical Experimenter  for  the  last  two  years 
and  have  benefited  greatly  by  reading  it. 

LEONARD  P.  NIESSEN. 
Milwaukee,  Wis. 


46 


THE  ELECTRICAL  EXPERIMENTER 


May,  1917 


PAUL  RALSTON'S  RADIO 
STATION. 

With  the  exception  of  the  pair  of  Bran- 
ches' phones,  a  l/i  k.w.  Packard  trans- 
former and  the  rotary  gap  motor,  this  set 
is  all  of  my  own  construction. 


Paul  Ralston,  of  Conneaut  Lake,  Pa.,  Is  an 
Ardent  Student  of  the  Art  of  Wireless  Teleg- 
raphy. 


The  normal  sending  range  is  50  miles. 
Altho  1  have  not  a  license,  I  receive  sta- 
tions as  far  as  Key  West  (1,200  miles  dis- 
tant).   My  call  is  1HR. 

I  have  also  increased  the  efficiency  of  my 
station  by  adding  an  Oscilaudion  bulb,  a 
new  rotary  gap  and  an  oscillation  trans- 
former. 

PAUL  RALSTON. 
Conneaut  Lake,  Pa. 

550   WIRELESS    MEN  AVAILABLE 
IN  PHILADELPHIA. 

A  trained  body  of  300  expert  wireless 
operators  now  working  on  ships  at  sea  or 
at  commercial  or  naval  stations  along  the 
coast,  and  250  amateurs  capable  of  com- 


The  Waco,  Texas,  High  School  Radio 
Club. 

In  September,  1914,  the  Waco  High  School 
Radio  Club  was  organized  with  a  charter  member  - 
ship of  four. 

To-day  the  club  has  an  active  membership  of 
thirty,  a  first-class  one  kilowatt  transmitting  set, 
two  receiving  sets  (one  an  ordinary  4,000  meter 
Audion  set  and  the  other  a  2,500  meter  regen- 
erative set),  hot  wire  ammeter,  wave  meter,  motor- 
generator  set,  Multi-Audifone  set,  Omnigraph  and 
various  other  experimental  apparatus. 

The  Radio  call  is  5  YG.  The  club  meetings 
are  held  every  Friday  evening.  The  club  would 
welcome  all  communications  sent  to  Willis  F. 
McCracken,  care  of  Waco  High  School  Radio 
Club,  Waco  High  School,  Waco,  Texas. 

Ypsilanti  Radio  Amateur  News. 

The  Ypsilanti  Radio  Amateurs  have  elected  the 
following  officers  for  the  coming  year: — President, 
Donald  Knight;  Secretary.  Allen  Rust;  Treasurer, 
James  Orr;   Sergeant-at-Arms,  Louis  Roberts. 

The  club  participated  in  a  local  exhibit'  during 
America's  Electrical  Week. 

School  Forms  Radio  Club  at  Arlington, 
Mass. 

A  wireless  club  was  formed  by  the  pupils  of 
the  Russell  Grammar  School  of  Arlington,  Mass., 
during  the  month  of  November. 

The  following  officers  were  elected: — President, 
Ernest  A.  Snow,  Jr.;  Vice-President,  Richard 
Noyes:   Secretary -Treasurer,  Borden  Billings. 

The  club  has  a  set  installed  and  meets  Tues- 
days and  Thursdays  in  the  afternoon  to  study  the 
code. 


Dansville  Wireless  Association  of 
Dansville,  N.  Y. 

On  December  28,  1916,  a  number  of  "live  wire 
radio  amateurs  organized  the  Dansville  Wireless 
Association. 

The  Club  has  twelve  members  and  the  station 
is  located  within  the  school  building  and  would 
like  to  get  in  touch  with  other  active  clubs  and 
amateurs. 

The  officers  of  the  club  are  James  Welch,  Presi- 
dent: Nobert  Smith,  Secretary  and  Conway  J. 
Sheerin.  Chief  Operator. 


Uper  Sandusky,  Ohio,  Wireless  Club. 

The  amateurs  of  LTpper  Sandusky,  Ohio,  have  or- 
ganized a  club  and  have  located  in  the  business 


pleting  their  radio  studies  within  a  few 
months,  is  Philadelphia's  contribution  to 
the  nation  in  the  important  branch  of  wire- 
less communication  in  event  of  war.  In 
addition,  forty  students  are  now  enrolled 
in  the  Philadelphia  School  of  Wireless 
Operating. 

This  school  was  the  first  to  be  estab- 
lished in  America.  It  was  started  with  a 
few  pupils  back  in  1911,  and  since  that 
time  has  turned  out  more  than  300  trained 
men,  nearly  all  of  whom  are  holding  com- 
mercial licenses  to-day. 

All  licenses  for  wireless  operating  are 
issued  by  the  federal  authorities,  so  that 
the  records  at  Washington  constitute  an 
index  of  the  operating  force  of  the  coun- 
try. In  this  respect  Philadelphia  is  said 
to  lead  every  other  city  with  its  250  ama- 
teurs. 

Altho  the  operation  of  wireless  stations 
is  kept  under  government  regulation,  no 
order  has  been  issued  since  the  breaking 
off  of  relations  with  Germany  to  make 
regulations  more  drastic,  and  none  is  ex- 
pected. In  some  respects  the  large  num- 
ber of  amateur  stations  means  better  pro- 
tection for  the  city,  for  there  is  hardly  one 
hour  out  of  the  twenty-four  when  some 
stations  are  not  operating  or  listening. 

In  addition  to  this  force,  Philadelphia 
is  guarded  by  three  powerful  stations, 
Wanamaker's,  League  Island  and  Cape 
May.  Most  of  the  commercial  business  of 
the  city  is  handled  over  the  plant  on  the 
roof  of  the  Wanamaker  store.  This  is 
rated  at  10Q  miles,  but  its  messages  have 
been  picked  up  as  far  south  as  Florida. 
The  plant  is  generally  closed  now  at  night, 
but  should  the  need  arise  it  could  be  kept 
in  constant  operation  and  could  pick  up 
messages  from  a  considerable  distance  out 
in  the  Atlantic. 


Amateur  News 

section  ot  the  town.  The  society  consists  of  seven- 
teen members.  We  are  installing  a  1  K.  W.  trans- 
former and  expect  to  install  an  Audion  set  in  the 
near  future. 

The  following  officers  were  elected  on  December 
1,  1916:  Ralph  Casey,  President;  Robert  Maskey, 
Vice-president;  Russel  Selligman,  Secretary  and 
Hillis  Berkey,  Treasurer. 

Radio  Amateur  League. 

The  Radio-Amateur  League  of  Grand  Prairie 
and  Dalworth  Park,  Texas,  was  organized  March 
5,  and  the  following  officers  were  elected:  Frank 
M.  Stubbs,  President;  Arthur  Bradshaw,  Vice- 
president;  Ivan  Ferguson,  Secretary  and  Treas- 
urer; Joe  Ward  Edwards,  Chief  Radio-Engineer 
and  Press  Reporter. 

The  "League"  intends  to  construct  most  of  its 
own  instruments.  We  wish  to  communicate  with 
other  clubs  and  learn  of  their  ideas.  We  have 
several  ideas  on  the  "Erection  of  Aerials"  and 
the  construction  of  other  instruments  which  we 
will  communicate  to  any  clubs  desiring  this  idea. 

All  communications  may  be  addrest  to  the  secre- 
tary at  Dalworth  Park,  and  to  the  President,  or 
Radio-Engineer,  at  Grand  Prairie,  Texas. 


Fifth  District  Radio  Club  Elects 
New  Officers. 

In  compliance  with  the  by-laws  of  the  club,  Mr. 
R.  B.  Godbold  was  re-elected  President;  Karl  Frueb- 
ing.  Secretary -Treasurer  and  George  Deiler,  Li- 
brarian, who  will  serve  the  club  until  July,  1917. 

pllIlllllDllII 

1  RADIO    CLUBS    ATTENTION!  j 


J      We  are  always  pleased  to  hear  ( 

j  from   young   Edisons  and   Radio  ; 

jj  Clubs.    Send  a  write-up  of  your  J 

J  Club  with  photos  of  members  and  ■ 

J  apparatus  to-day  to:  Editor  "Ama-  J 

1  teur  News"  Section,  The  Electri-  J 

1  cal  Experimenter,  233  Fulton  St.,  ] 

1  New  York  City.  1 


GIVE  COLLEGE  RADIO  OUTFIT. 

bt.  Ignatius  s  college  of  Cleveland,  O., 
was  presented  with  a  new  wireless  outfit  at 
an  alumni  smoker  in  the  college  gymnasium 
on  February  twentieth.  The  outfit  was  the 
gift  of  the  alumni  of  the  institution.  Dr. 
Charles  S.  Howe,  president  of  Case  School 
of  Applied  Science,  delivered  an  address. 

HARRY  WALLE'S  AMATEUR 
RADIO  STATION. 

I  present  herewith  a  photograph  of  my 
wireless  station,  to  be  entered  in  your 
"Amateur  Radio  Station  Contest."  My  set 
employs  a  4  wire  aerial  60  feet  long. 
The  receiving  apparatus  comprises  a  loose 
coupler,  variometer,  variable  condenser, 
fixt  condenser  and  a  50  tap  tuning  coil, 
which  are  all  mounted  complete  in  an  oak- 
finished  cabinet.  The  receivers  are  Trans- 
Atlantic  2,800  ohm  type.  The  sending  out- 
fit includes  a  1-inch  spark  coil,  helix,  spark 


Harry  Walle  Finds  Keen  Enjoyment  in  His 
Small  But  Efficient  Radio  Station. 


gap  and  a  key.  I  hear  8  U  E,  8  R  Y  and 
8  G  L  very  clearly. 

HARRY  VANDE  WALLE. 
Cincinnati,  Ohio. 


The  Headquarters  of  the  Club  are  in  the  rooms  of 
the  Y.  M.  C.  A.  Radio  School.  The  club  owns  a 
moderate  library  and  has  the  use  of  a  fine  receiv- 
ing station,  also  a  storage  battery  charging  plant. 

Invitations  are  extended  to  all  interested  in  the 
Radio  Art.  Meetings  are  held  every  Saturday 
night.  Photographs  of  the  club's  set  will  be 
mailed  upon  request.  We  would  also  like  some 
pictures  from  other  clubs.  Address  all  communi- 
cations to  Karl  Fruebing,  1232  Magazine  Street, 
New  Orleans,  La. 


Eureka,  Illinois,  Radio  Amateur  News. 

On  the  evening  of  March  7,  the  Eureka  Radio 
Club  was  formed  and  ten  members  admitted.  The 
following  officers  were  elected:  Alvin  Spencer, 
President;  Glenn  Dorward,  Vice-president  and 
Henry  Klaus,  Secretary-Treasurer. 

All  communications  should  be  addrest  to  the 
Secretary-Treasurer. 


Y.  M.  C.  A.  Radio  Club  of  Springfield, 
Ohio. 

Under  the  leadership  of  Mr.  E.  Hineline,  the 
amateurs  of  Springfield,  Ohio,  recently  organized 
a  radio  club,  which  promises  to  be  one  of  the 
most  successful  organizations  of  that  locality. 
Widespread  publicity  was  given  in  the  local  news- 
papers and  it  is  reported  that  there  are  a  large 
number  of  men  and  boys  who  are  taking  interest 
in  wireless  telegraphy.  They  have  erected  aerials 
and  provided  instruments,  but  so  far  have  been 
working  at  cross-purposes  with  few  people  to  talk 
to  and  no  organization  to  further  the  work,  so 
there  is  a  need  for  a  progressive  club  of  amateurs. 

The  members  of  the  club  have  planned  a  sending 
set,  capable  of  sending  two  hundred  miles,  and  a 
long-distance  receiving  set  to  receive  all  high- 
powered  stations  in  this  country  and  Europe.  In 
organizing  the  club,  Springfield  becomes  a  center 
of  activity  for  amateur  wireless.  One  of  the  prin- 
cipal objects  of  the  Club  will  be  to  teach  its  mem- 
bers the  use  of  the  Continental  Code  and  Mr. 
Hineline  hopes  to  interest  the  Y.  M.  C.  A.  in 
the  new  club  and  in  this  way  induce  a  large 
number  of  boys  to  participate.  The  temporary 
organization  which  was  effected  at  the  second  meet- 
ing placed  the  following  officers — Harold  Stead- 
man,  President;  J.  W.  Fenton,  Vice-president; 
E.  J.  Grieb.  Secretary;  Mr.  Baldridge,  Treasurer 
and  J.  W.  Wright,  Assistant  Treasurer. 

Address  all  communications  to  the  Secretary, 
121  Rose  St.,  Springfield,  Ohio. 


May,  1917 


THE  ELECTRICAL  EXPERIMENTER 


47 


EXPERIMENTAL  PHYSICS. 

(Continued  from  \page  2$) 
a  pointer  which  moves  around  and  points 
to  a  circular  scale  which  has  been  cali- 
brated to  read  the  same  as  the  ordinary 
mercury  barometer. 
EXPERIMENT  23— 

A  thin  bottle  (preferably  a  Florence 
flask)  is  tightly  corked  with  a  rubber  stop- 
per, thru  which  a  thin  glass  tube  is  con- 
nected. If  this  is  inverted  into  a  glass 
containing  water  to  which  a  few  drops  of 
red  ink  have  been  added  and  the  bottle  is 
now  heated,  gently  the  air  in  the  bottle 
will  expand  and  some  will  pass  into  the 
water  (see  Fig.  19).  If  now  the  bottle  is 
allowed  to  cool,  some  of  the  liquid  will 
rise  in  the  tube.  If  the  colored  water  rises 
above  half  way  up  the  tube  some  of  it  can 
be  let  out  by  raising  the  tube  above  the 
level  of  the  water  in  the  glass.  This  ap- 
paratus can  now  be  used  as  a  crude  ther- 
mometer for  obviously  if  heat  is  applied 
to  the  bottle,  the  air  in  the  bottle  will  ex- 
pand and  push  the  water  in  the  tube  back 
towards  the  glass;  if  a  colder  tempera- 
ture is  applied  the  reverse  will  happen  and 
the  water  will  rise  in  the  tube.  The  hot- 
ter the  temperature  the  lower  the  level 
in  the  tube  and  the  colder  the  temperature 
the  higher  the  level  in  the  tube.  This  ex- 
periment was  first  performed  by  the  great 
Galileo  and  was  the  first  method  of  meas- 
uring temperatures. 
EXPERIMENT  24— 

If  a  little  ice  is  gradually  added  to  some 
water  in  a  highly  polished  vessel  (a  piece 
of  the  family  silverware  just  answers  the 
purpose)  while  the  water  is  being  stirred 
and  a  thermometer  is  kept  in  it,  a  tempera- 
ture will  be  reached  when  the  polished  sur- 
face fogs,  i.e.,  (moisture  forms  on  it). 
This  temperature  varies  according  to  con- 
ditions of  the  atmosphere  and  is  called  the 
c';wpoint.  This  moisture  does  not  leak 
thru  the  vessel  as  is  commonly  supposed 
but  condenses  from  the  atmosphere.  We 
are  all  familiar  with  this  phenomenon,  hav- 
ing observed  it  every  summer  whenever 
ice  water  is  served.  The  explanation  is 
as  follows — moisture  is  continually  evap- 
orating into  the  atmosphere  and  when  the 
atmosphere  contains  as  much  moisture  as 
it  can  hold,  it  is  said  to  be  saturated.  The 
same  amount  of  air  can  hold  more  and 
more  moisture  as  the  temperature  is  in- 


creased and  vice  versa.  Hence  if  the  at- 
mosphere is  saturated  and  the  temperature 
is  decreased,  some  of  the  moisture  will 
have  to  condense  as  the  atmosphere  cannot 
hold  more  moisture  than  as  much  as  it  can 
hold.  Likewise  if  the  atmosphere  is  not 
saturated  cooling  it  will  saturate  it  and 
further  cooling  will  cause  moisture  to 
condense. 

The  cooling  of  the  grass,  trees,  stones, 
etc.,  at  night  more  rapidly  than  the  atmos- 
phere itself  cools,  causes  the  formation 
of  dew  (a  condensation  from  the  atmos- 
phere). If  the  air  near  the  earth  also 
cools,  the  condensation  also  takes  place  on 
the  dust  particles  near  the  earth  and  this 
condensation  is  called  a  fog.  If  this  fog 
forms  at  some  distance  above  the  surface 
of  the  earth,  it  is  called  a  cloud.  If  a 
considerable  amount  of  moisture  condenses 
in  the  cloud  the  drops  become  large  and 
because  of  their  weight  fall  as  rain.  Rain 
passing  thru  cold  regions  freezes  into  hail. 
If  the  temperature  of  condensation  is  be- 
low freezing  the  moisture  condenses  into 
crystals  called  snowflakes. 

(  To  be  continued ) 


Amateur  Radio  Stations  Licensed  by  the  Bureau  of  Navigation  During 
the  Month  of  September,  1916  (Concluded) 


FIRST  DISTRICT 


Call 
Signal 


8DE 
8OF 

8KE 

8AMX 

8BG 

8OC 

8RF 

8PH 

8HX 

8AMC 

9AJW 

9AIL 

9GH 

9AKB 

9AJT 

9AJR 

9AKF 

9AKG 

9AKJ 

9AJO 

9A.IS 

9VD 

9AKA 

9AKF. 

9AKH 

9AKD 

9HG 

9AKC 

9VQ 

9A.IU 

9AKK 

9AKT 

9AKL 


Owner  of  station 


Frost,  Norbert .  . . 
Hewitt,  C.  Tefft. 


Houk,  Robert  J  

Moyer,  Edward  A  

Peacock,  Howard  

Simons,  Harold  C  

Slape,  Frank  

Thomas,  William  K. . .  . 

Towsley,  Paul  W  

Warden,  William  F.,  Jr. 


Baer,  Elwynn  W  

Becker,  Alby  

Branom,  Albert  L  

Davis,  Laurence  O. .  .  . 

Dubuque  College  

Fox,  Harry  

GitchofT,  Anton  A  

Hamlett,  Robert  T. . . . 
Hammond,  George  R. 

Hardy,  Reginald  

Herr,  Carl  E  

Herron,  Carson  L. . .  . 
Holmberg,  Harry  E. . . 

Keller,  Warren  H  

McBride,  Kenneth. . . 

Markley,  Max  

Nelson,  Earl  P  

Niessen,  Leonard  P. . 

Poser,  Stanley  F  

Robinson,  Roy  E  

Eyder,  Earl  

Tuhtar,  Eugene  W.. . 
Werlein,  Edwin  


Location  of  station 


552  Glenwood  Ave.,  Buffalo,  N.  Y. 
7942  Westmoreland  Ave.,  Swiss- 

73  Douglas  St.',' Tiffin,'  Ohio'. '.  

640  N.  Sandusky  St.,  Bellevue.Ohio 

Barker,  N.  Y  

617  May  St.,  Lansing,  Mich  

106  Eureka  St.,  Pittsburgh,  Pa. .  . 
400  Minton  St.,  Pittsburgh,  Pa. .  .  . 
1019  Bement  St.,  Lansing,  Mich..  . 
R.  F.  D.  No.  11,  Cuyahoga  Falls,  O. 

NINTH  DISTRICT 

...  1710  4th  St.,  Madison,  111  

...  3146  32d  St.,  Catlettsburg,  Ky  

.  .  .  208  Giddings  Ave.,  Jerseyville,  111. 

.  .  .  Hazard,  Ky  

.  .  .  Dubuque,  Iowa  

...  3116  N.  24th  St.,  Omaha,  Neb  

.  .  .  500  5th  St.,  Madison,  111  

.  .  .  Fulton,  Ky  

. .  .  .  219  S.  5th  Ave.,  Selwein,  Iowa. . .  . 

  441  49th  Ave.,  West  Allis,  Wis.  .  .  . 

  540  9th  St.,  Red  Wing,  Minn  

.  .  .  .  1712  Court  St.,  Le  Mars,  Iowa. .  .  . 

. . . .  Bottineau,  N.  D  

.  .  .  .  101  Lincolnway,  La  Porte,  Ind  

.  .  .  .  101  Bowen  Ave.,  Independence, Mo. 
.  .  .  .  416  W.  Central  Ave.,  Bluffton,  Ind. 
.  .  .  .  1320  Commercial  St.,  Waterloo,  la. 
.  . . .  430  Layton  Blvd.,  Milwaukee.Wis. 

  730  1st  St.,  Milwaukee,  Wis  

.  .  .  .  3257  Alcott  St.,  Denver,  Colo  

  806  S.  College  St.,  Springfield,  111. . 

  503  6th  St.,  Milwaukee,  Wis.  ,  

.  . .  .  4060  Lincoln  Ave.,  Chicago,  111  


A  ONE-MAN  ELECTRIC 
SUBMARINE. 

(Continued  from  page  6) 
on )  to  make  several  short,  quick  trial 
maneuvers,  until  he  bumps  into  the  hull  of 
the  enemy  vessel.  Also  he  can  see  a  dis- 
tance of  25  to  50  feet  or  more  under  water 
by  means  of  the  powerful  electric  search- 
light, and  once  against  the  hull  of  the  ene- 
my Submarine  or  Dreadnought,  it  is  but  the 
work  of  a  moment  to  excite  the  electro- 
magnets in  the  war-head  which  instantly 
grip  the  steel  plates  of  the  enemy  vessel 
with  a  powerful  hold,  and  to  release  the 
war-head  by  means  of  the  electro-mag- 
netic clutches  previously  mentioned.  The 
operator  then  scurries  away  at  a  mile-a- 
minute  speed,  and  if  he  is  but  one  quarter 
of  even  one-eighth  of  a  mile  away  when 
the  war-head  explodes,  he  will  be  safe. 
In  the  event  that  the  comprest  air  and  gas- 
oline engine  driving  machines  should  both 
fail  on  his  return  trip,  he  can  send  out 
distress  rockets  thru  the  rocket  shute  at- 
tacht  to  the  periscope  column,  and  thus 
be  rescued  by  a  boat  from  the  mother-ship 
or  by  patrol  boats  sent  out  from  shore. 

MAGNETIC  IN- 
DICATOR FOR 
CRITICAL  TEM- 
PERATURES. 

The  fact  that 
steel  loses  its  mag- 
netic properties  on 
attaining  the  criti- 
cal temperature 
forms  the  basis  on 
which  has  been  de- 
signed an  instru- 
ment which  infall- 
ibly indicates  the  in- 
stant when  a  mass 
of  steel  has  attained 
the  decalescent  or 
hardening  point. 
The  instrument 
consists  of  a  con- 
tact box  contain- 
ing magnet  and 
coils,  mounted  on 
one  end  of  a  rod 
provided  with  han- 
dles and  heat  shield. 
The  other  end  of  the 
rod  carries  a  flux- 
meter,  the  needle  of 
which  indicates  the 
gradual  approach  of 
the  steel  to  the  non- 
magnetic or  critical 
point. 


Power 
kilowatt 


THE  THERAPY  OF  LIGHT  AND 
THE  NEW  "R-RAY." 

(Continued  from  page  15) 

radiation  is  somewhat  similar  to  the  Ultra- 
violet ray,  inasmuch  as  an  arc  is  used ; 
but  two  different  arc  electrodes  are  em- 
ployed in  this  work.  The  arc  is  produced 
between  an  electrode  composed  of  quartz 
and  mercury  with  a  second  electrode  of 
ordinary  arc  carbon.  Fig.  1  shows  one 
of  the  complete  arc  lamps  used  in  these 
experiments. 

Viewed  as  a  soectrogram  the  R-ray  oc- 
cupies one  side  of  the  Ultra-violet  region, 
and  grades  uniformly  from  the  first  octave 
to  out  and  beyond  the  visible  portion.  Al- 
so here  we  find  radiations  that  cause  air 
and  matter  to  have  such  affinity  that  they 
are  instantly  absorbed,  and  investigation 
of  their  characteristics  can  only  be  con- 
ducted in  a  vacuum. 

As  resultant  deductions  of  therapeutic 
interest  in  considering  the  properties  of  the 
R-ray,  we  find  the  following: 

(1)  They  are  readily  controllable  and 
give  penetrative  therapeutic  light  of  unin- 
terrupted intensity. 

(2)  They  are  rich  in  Ultra-violet  rays 
of  shorter  wave  lengths  than  the  emissions 
from  any  other  known  arc. 

(3)  They  differ  materially  from  X-rays 
in  that  they  may  be  deflected  and  focussed 
on  any  given  area,  so  as  to  combine  their 
inherent  heat-ray  value  with  their  visible 
and  invisible  light  radiations. 

(4)  They  are  more  readily  absorbed  by 
matter  than  any  present  known  arc  ray, 
and  as  such  secure  vibratory  reactions  in 
deep-seated  cellular  organisms. 

In  order  to  show  the  position  of  the  un- 
mapt  region  wherein  the  R-ray  lies,  and  as 
compared  with  the  vibrations  of  other 
sources  of  radiation,  the  chart,  Fig.  2  was 
made.  It  will  be  found  very  interesting  to 
those  who  are  pursuing  the  study  of  differ- 
ent sources  of  radiations. 

The  chart  indicates  the  wave  lengths  of 
radiations  ranging  from  the  visible  part  of 
the  spectrum  to  X-rays  and  the  Gamma 
rays  of  radium. 

To  fully  understand  this  chart,  the  fol- 
lowing notation  is  used :  the  numbers  across 
the  top  give  their  respective  wave  lengths 
in  Angstrom  units  (one  Angstrom  unit  is 
equal  to  1/10  of  a  meter  and  this  unit  is 
abbreviated  as  A.U.).  Thus  the  waye 
lengths  are  given  in  tenths  of  a  meter, 
using  here  the  language  of  the  scientist. 
The  Angstrom  unit  is  equivalent  actually 
to  1010  meter,  one  meter  being  equal  to 
39.37  inches.  The  numbers  below  represent 
the  number  of  octaves  which  these  rays 
range  over. 

The  region  of  about  six  octaves,  begin- 
ning at  4  and  ending  at  10,  represents  the 
unmapt  portion.  This  separates  the  ex- 
treme ultra-violet  from  the  commencement 
of  the  very  soft  X-rays.  The  most  easily 
absorbed  X-rays,  whose  wave  length  has 
been  determined,  are  the  characteristic  rays 
of  burning  aluminum  with  a  wave  length  of 
8.4  A.U.  Passing  up  thru  several  octaves 
of  X-rays,  the  limit  indicated  by  the  line 
"N"  is  reached;  these  represent  the  hardest 
i.e.,  the  most  penetrating  X-rays,  which 
have  so  far  been  produced.  The  line  "M" 
represents  the  medium  penetrating  ray.  It 
will  be  noticed  that  some  of  the  gamma 
rays  as  produced  by  the  disintegration  of 
the  radium  atom,  are  of  longer  wave 
lengths  than  some  of  the  shorter  X-rays. 

The  region  ranging  between  octaves  4 
and  10  are  vibrations  which  are  easily  ab- 
sorbed by  matter.  They  vary  in  wave 
length  from  approximately  900  to  9  A.U. 
The  region  between  wave  lengths  3,800  to 
1,900  is  the  portion  of  radiation  which  is 
of  therapeutic  interest. 


THE  ELECTRICAL  EXPERIMENTER 


May,  1917 


PATENTS 


Magnetic  Drilling  Attachment 

(No.    1,219,190;    issued    to  Henry 
Symes.) 

The  inventor  here  provides  an 
electro-magnetic  means  of  feeding 
a   machine    drill   against    its  work. 


An  iron  frame  supports  the  drill 
spindle,  which  is  driven  by  an  elec- 
tric motor.  The  spindle  carries  a 
suitable  iron  yoke  and  pole-pieces 
which  are  acted  upon  attractively 
by  powerful  solenoid  electro-mag- 
nets, tending  to  pull  the  iron  pole- 
pieces  within  in  the  coils.  The  cur- 
rent supplied  the  magnet  coils  can 
be  varied  to  give  various  degrees  of 
pull  on  the  drill  frame.  For  long 
vertical  action  two  or  more  sets  of 
solenoids,  one  above  the  other,  can 
be  utilized  as  shown. 


Electric  Phonograph  Recorder 
and  Reproducer 

(No.    1,218,799;   issued   to  Herman 
G.  Pape.) 
A  device  for  making  phonograph 


records  and  combining  in  its  make- 
up a  suitable  electro-magnet,  a  dia- 
fram,  and  a  means  for  causing  the 
diafram  to  vibrate  in  response  to 
electrical  impulses  in  the  electro- 
magnet— as  from  a  microphone. 
Acoustic  vibrations  or  sounds  can 
operate  the  diafram  as  usual  thru 
an  open  grid  above  it,  a  stylus  being 
connected  to  the  diafram  to  vibrate 
with  it. 

Electric  Voting  Machine 

(No.  1,219,053;  issued  to  Marshall 
F.  Thompson  and  Arthur  L. 
Townsend.) 


fl£V  TT  <T 
t=>o  e  0 

G30     O  O 
DO    O  • 

CZZ30    0  0 
C=3  O    O  O 

a=30  0  0 

6»TTt«Y 
0UTT0H     0M  Qf 


An  electrically  operated  voting 
board  which  includes  provision  for 
totaling  and  recording  all  of  the 
votes  cast  and  flashing  them  up  on 


an  indicator  board  The  primary  cir- 
cuit includes  a  voter's  circuit  closer, 
a  visual  lamp  signal  and  a  relay 
magnet.  The  latter  closes  a  secon- 
dary circuit  including  the  visual  sig- 
nal and  a  vote  recording  mechan- 
ism. Also  there  is  provided  a  spe- 
cial circuit  breaking  attachment  out 
of  control  of  the  voter,  for  the  pur- 
pose of  breaking  the  primary  or 
voter's  circuit.  The  idea  is  par- 
ticularly applicable  to  government 
and  society  meeting  chambers,  mak- 
ing it  possible  to  record  and  an- 
nounce the  vote  of  members  present 
in  the  minimum  of  time. 


Magnetic  Speedometer 
(No.  1,219,245;  issued  to  Allen  A. 
Canton.) 


A  radical  departure  in  speed- 
ometer design,  involving  the  use  of 
a  permanent  steel  magnet  of  ring 
form,  over  which  are  placed  two 
movable  magnet  windings,  one  of 
which  is  supplied  with  a  constant 
electric  current  and  means  for  in- 
termittently supplying  electric  cur- 
rent to  the  second  solenoid  coil. 
The  magnetic  reaction  occurring 
with  such  an  arrangement  causes 
the  coils  to  move.  In  so  doing  they 
rotate  a  geared  sector,  as  shown, 
the  sector  teeth  meshing  with  a 
small  gear  pinion  fixt  rigidly  to  the 
dial  shaft,  thus  causing  the  num- 
bered dial  to  move  under  an  obser- 
vation slot  or  window. 

High  Frequency  Oscillation  Appar- 
atus 

(No.   1,216,646;  issued  to  James  C. 
Armor.) 


A  novel  scheme  for  producing 
high  frequency  oscillations  for  ra- 
dio-telegraphy, radio-telephony  and 
similar  arts.  Using  alternating  or 
direct  current  as  a  source,  the  in- 
ventor provides  choke  coils  8  and 
resistances  7,  across  which  is  shunt- 
ed the  special  spark  gap  4-4.  This 
gap  is  shunted  by  an  oscillatory  cir- 
cuit comprising  suitable  condenser  9 
and  inductance  10.  The  first  dis- 
charge wave  of  the  condenser  across 
the  gap  is  quenched  by  blowing  a 
high  velocity  (5,000  ft.  per  second) 


jet  of  gas  or  fluid  between  the  rapid- 
ly rotating  spark  discs  4,  4.  Higher 
efficiency  is  claimed  and  the  pro- 
duction of  extremely  high  fre- 
quency, dead-beat  unidirectional  dis- 
charges. 


Hearing  Device 


(No.  1,219,411;  issued  to  Charles 
E.  Williams.) 
A  specially  sensitive  electric  tele- 
phone device  to  aid  partially  deaf 
people  to  hear  better.  Operating  on 
the  dictograph  principle  it  com- 
prises a  super-sensitive  microphone 
which  is  connected  with  a  suitable 
telephone  receiver  and  a  high  volt- 
age battery.  The  battery  comprises 
a  plurality  of  cells  and  means  for 
reducing  the  high  potential  by  hav- 
ing an  extra  resistance  wire  between 
a  terminal  on  one  cell  and  a  pole 
of  another,  with  flexible  connec- 
tions between  the  external  terminals 
to  the  receiver  and  microphone. 

Radio  Transmitting  System 


(No.    1,216,615;    issued    to  George 
Seibt.) 

A  radio  transmitter  operating  on 
direct  current,  which  is  supplied  to 
a  quenched  gap,  thru  suitable  choke 
impedances  and  resistances.  A 
suitable  coupling  is  provided  to  en- 
able the  cutting  off  of  oscillations 
in  the  closed  primary  oscillating  cir- 
cuit after  the  first  beat  of  the  os- 
cillations. The  spark  gap  is  de- 
signed to  be  short,  and  a  rapid  heat 
dissipater,  thus  quenching  the  spark 
and  giving  rise  to  powerful,  slowly 
damped  free  oscillations  in  the 
secondary  or  aerial-ground  oscillat- 
ing circuit  and,  it  is  claimed,  that 
the  two-coupled  oscillations  practi- 
cally disappear.  This  system  is 
adapted  to  radio-telephony,  using  a 
microphone  in  the  ground  lead. 


Submarine.  Subterranean  and 
Aerial  Telephony 

(No.   1,212,202;  issued  to  Reginald 
A.  Fessenden.) 
A  new   phase   of  the  Fessenden 


system  of  setting  up,  transmitting 
and  receiving  powerful  sound  waves 
in  the  form  of  telegraphic  and  tele- 
phonic signals  thru  water,  land  or 
air.     Prof.   Fessenden  here  invokes 


the  use  of  the  Alexanderson  mag- 
netic amplifier  11-13,  with  which  to 
control  by  microphones,  the  output 
of  say  a  100  K.W.  radio  frequency 
alternator.  This  R  F.  current  is  past 
(also  modulated  by  secondary  11) 
thru  a  rectifier  17,  thence  into  a 
non-inductive  oscillator  20.  This  is 
linked  up  with  a  metallic  beam  gir- 
der 23,  supported  at  two  points,  as 
shown,  and  carrying  a  large  metal 
diafram    26,    say    50    feet  square. 


Precision  Variable  Inductance 

(No.    1,217,348;    issued    to    O.  F. 
Rothen.) 

The  smallest  part  of  a  turn  of  the 


spiral  may  be  accurately  tuned  in 
or  out  of  the  circuit  by  simply  turn- 
ing the  central  knob  or  handle. 
Spiral  inductances  of  this  type  in- 
variably have  the  defect  that  the 
slider  will  not  follow  the  turns. 
Here  the  inventor  provides  a  toothed 
rack  on  the  slider  arm  which  co-acts 
on  a  fixt  central  gear  stud,  so  that 
as  the  handle  is  turned  the  slider 
arm  is  moved  in  or  out  accordingly 
and  in  a  spiral  path  the  complement 
of  the  helix.  The  pitch  circum- 
ference of  the  stationary  pinion  is 
selected  equal  to  the  radial  pitch 
of  the  spiral. 


Electric  Musical  Instruments 

(No.  1,216,829;  issued  to  Harry  S. 
Martin.) 

When  an  interrupted  current  of 
the  frequency  corresponding  to  any 
certain    musical    note    is    fed  into 


COPIES  OF  ANY  OF  THE  ABOVE  PATENTS  SUPPLIED  AT  10c  EACH 


electro-magnet  16,  it  causes  pulsat- 
ing magnetic  forces  to  act  on  the 
tuned  reed  13.  This  in  turn  sets 
the  diafram  1 1  vibrating  at  a  cor- 
responding periodicity,  which  vibra- 
tions are  communicated  to  the  col- 
umn of  air  in  horn  1,  thru  the  an- 
nular mouth  3.  Diafram  11  carries 
a  felt  ring  22,  which  may  be  dis- 
pensed with  for  certain  effects.  By 
this  means  it  is  claimed  that  ex- 
tremely powerful  and  unusual  son- 
orous vibrations  are  set  up. 


May,  1917 


THE  ELECTRICAL  EXPERIMENTER 


49 


PHONEY  PATENT  OFFIZZ 


Jq.r 

No.\te 


M. 


Q.S.B. 


>Q.S.C. 


To  Whom  It  Should  Worry: 

Let  it  be  knowed  to  all  fathers,  fatheads, 
mothers,  parents,  and  elders  thruout  the 
land  and  the  seven  seas  and  lakes,  that  I, 
Constantine  Ulysses  Spidor  of  the  City  of 
Peramblator,  in  the  state  of  prolonged 
coma,  have  imagined,  conceived,  designed 
and  executed,  at  the  risk  of  my  imperfect 
sanity,  an  apparatus  which  will  revolution- 
ize the  baby  industry  and  do  away  forever 
with  "the  hand  that  rocks  the  cradle." 

It  is  a  greatly  to  be  lamented  fact  that 
our  national  baby  industry  has  suffered 
greatly  during  the  past  decade,  primarily 
for  the  reason  that  babies,  infants,  brats 
and  other  similar  nuisances  tend  to  keep 
their  elders  at  home  and  away  from  tango 
parlors  and  the  "movies."  Not  that  the 
parents  cherish  the  idea  of  staying  in,  no, 
not  that.  They  hafto.  For,  if  the  nurse  or 
hired  girl  take  their  daily  spin  in  the  fam- 
ily "Tin-lizzie,"  who  would  feed  the  brat 
to  still  his  or  her  war-whooping? 


AUTOMATTICK  BRAT  HUSHER 
C.  U.  SPIDOR  OF  PERAMBLATOR,  CA. 

Species  Fikation  of  Patent  Lettors 

may  now  tango  or  "movie"  all  night,  if 
so  desired,  without  in  the  least  retarding 
the  natural  growth  of  their  offspring.  Also 
and  most  important  of  all,  "Pah-pah"  need 
no  longer  invent  new  forms  of  sudden 
strokes,  cramps,  colds,  fevers,  chills,  etc., 
which  make  it  impossible  for  him  "just 
then"  to  leave  a  comfortable,  warm  bed,  in 
order  to  perform  the  twice-nightly  Mara- 
thon with  an  obstreperous  brat,  clutched 
.  tightly  in  his  arms. 

Having  thus  explained  my  invention  in 
non-technical  terms,  I  now  refer  to  the  pat- 
ent drawing  for  further  elucidation: 

1,  is  a  sensitive  (but  happily  unfeeling) 
microfone.  The  first  brat-yell  jars  its  sen- 
sibility to  such  an  extent  that  current  be- 
gins to  flow  thru  it  at  a  terrific  rate,  which 
in  turn  operates  electromagnet  2.  This  ac- 
tuates pawl  3  permitting  Thermos-bottle  4, 
containing  the  best  imported  Extract  de 
Cow  to  con-descent  downward  into  the 
brat's  fists.    Instinctly  the  Brat  stuffs  the 


Patent  Buscated 

not  satisfied  with  cow-juice  and  perambu- 
lating joy  rides  only.  They  wish  to  be 
talked  to  and  sung  to.  Bearing  this  re- 
quirement in  mind,  when  bottle  4  is  empty 
and  has  ascended  once  more,  thanks  to 
coil-spring  13,  electromagnet  12  releases 
victrola  which  begins  to  talk  and  sing  lul- 
laby to  brat.  This  so  bores  the  latter  that 
he,  she  or  it,  falls  to  sleep  at  once. 

If,  perchance,  the  Brat  should  wake  up 
once  more  and  yell,  10  gets  busy  once  more 
and  perambuscates  at  once.  Spring  14  has 
reset  reproducer  15  in  the  meanwhile,  when 
mother's  original  selection  issues  forth 
anew.  This  so  disgusts  the  Brat  that  he, 
she  or  it,  falls  to  sleep  instanter. 
What  I  claim,  is: 

1°  A  self-contained  automattick  Brat- 
husher. 

2°  A  Brathusher  making  attending  par- 
ents and  nurses  unnecessary. 

3°  A  Brathusher  supplying  feed,  lullabys 
and  rocking  simultaneously. 


Let  it  Be  Knowed  to  All  Fathers,  Fatheads,  Mothers,  Parents,  and  Elders  thruout  the  Land  and  the  Seven  Seas  and  Lakes,  that  I  Constan- 
tine Ulysses  Spidor  of  the  City  of  Peramblator,  in  the  State  of  Prolonged  Coma,  Have  Imagined,  Conceived,  Designed  and  Excuted,  at  the 
Risk  of  my  Imperfect  Sanity,  an  Apparatus  Known  Hereinafter  as  an  "Automattick  Brat  Husher"  Which  Will  Revolutionize  the  Baby  In- 
dustry and  Do  Away  Forever  with  "the  Hand  That  Rocks  the  Cradle." 


The  sad  result  of  the  upshot  is,  that  the 
annual  total  production  of  babies  and  brats 
has  almost  reache  1  the  vanishing  point.  It 
is  also  to  be  noted  with  significant  signifi- 
cance, that  altho  everything  else  imagin- 
able has  gone  up  during  the  war,  only  the 
output  of  babies  and  brats  has  gone  down ! 
And  this  despite  of  the  constant  uproar- 
ous  roar  of  Teddy  from  Oyster  Bay. 

Happily,  such  disgraceful  conditions  need 
prevail  no  longer,  due  principally  and  solely 
to  my  marvelous  Automattick  Brat  Husher. 
By  using  this  inexpensive  apparatus,  parents 


nipple  in  its  empty  void  and  the  land  be- 
comes quiet  once  more.  But  this  is  not  the 
end  of  a  perfect  day.  Simultaneously 
with  the  descent  of  bottle  4,  a  contact  is 
made  and  electromagnet  5  attracts  switch 
6,  usually  held  off  by  spring  7,  which  now 
actuates  instinctanously  motor  8.  Gear  9 
takes  up  the  Q.S.T.  (General  Call)  and 
Perambulator  10  now  begins  to  perambus- 
cate  viciously  back  and  forward,  being 
thus  induced  by  arm  11. 

Neither  does  this  end  the  story.  Brats 
as  a  rule,  due  to  the  cunning  of  nature  are 


In  subscribing  to  the  above  facts,  I  have 
therefore  implanted  my  own  facsimile  oto- 
graf  hereunder  and  forever  on  this  27th 
day  of  Monday  in  the  53rd  year  after  the 
advent  of  the  safety-pin. 

C.  U.  SPIDOR. 

By  his  Attorney 
A.  Bruce  Brown, 
Norwich,  Conn. 
Witnoses: 
S.  H.  Utup 
Wade  U.  Givenus 
Fore  F.  Lusher 


So 


THE  ELECTRICAL  EXPERIMENTER 


May,  1917 


QUESTION  BOX 


This  department  is  for  the  sole  benefit  of  all  electrical  experimenters.  Questions  will  be  answered  here  for  the  benefit  of  all,  but  only  matter  of  sufficient  interest 
will  be  publisht.    Rules  under  which  questions  will  be  answered: 

1.  Only  three  questions  can  be  submitted  to  be  answered. 

2.  Only  one  side  of  sheet  to  be  written  on;  matter  must  be  typewritten  or  else  written  in  ink,  no  penciled  matter  considered. 

3.  Sketches,  diagrams,  etc.,  must  be  on  separate  sheets.    Questions  addrest  to  this  department  cannot  be  answered  by  mail  free  of  charge. 

4.  If  a  quick  answer  is  desired  by  mail,  a  nominal  charge  of  25  cents  is  made  for  each  question.  If  the  questions  entail  considerable  research  work  or  intricate 
calculations  a  special  rate  will  be  charged.    Correspondents  will  be  informed  as  to  the  fee  before  such  questions  are  answered. 


RADIO  QUERIES. 

(760.)  Harold  Janeway,  Edmonds, 
Wash.,  asks  : 

Q.  1.  Could  I  hear  amateur  stations  with 
a  loose  coupler,  galena  detector,  fixt  con- 
denser, and  an  Electro  "Government" 
'phone  in  connection  with  an  aerial  fifty 
feet  high  and  thirty  feet  long?  If  not  what 
other  instruments  would  I  need?  • 

A.  1.  There  is  no  reason  why  you  should 
not  receive  amateur  stations  with  the  in- 
struments you  mention.  A  variable  con- 
denser shunted  across  the  secondary  of 
your  loose  coupler  will  increase  the  selec- 
tivity very  much. 

Q.  2.  How  can  I  drill  holes  in  a  marble 
slab  so  that  I  can  mount  a  ground  switch 
upon  it? 

A.  2.  An  ordinary  steel  twist  drill  should 
be  employed  which  should  be  constantly 
kept  wet  by  applying  water  to  its  boring 
surface. 

Q.  3.  Would  I  be  violating  the  rules  of 
the  Fire  Underwriters  if  I  put  a  box  over 
my  outside  ground  switch  and  covered  the 
ground  wire  with  lath? 

A.  3.  Yes.  The  ground  wire  should  be 
kept  free  from  any  surrounding  objects. 

POWER  FROM  PRIVATE  PLANT. 

(760-A.)  W.  C.  Guibb,  Grabill,  Ind., 
wishes  to  know  : 

Q.  1.  What  is  the  best  way  to  use  the  out- 
put of  a  private  lighting  system  in  a  radio 
sending  set?  The  generator  has  an  out- 
put o-f  30  to  45  volts  and  13.3  amperes,  and 
charges  a  storage  battery  of  16  cells. 

A.  1.  The  best  way  to  utilize  the  electric 
power  generated  by  your  private  plant  is 
to  employ  a  spark  coil  outfit;  the  size  of 
the  coil  will  depend  upon  the  distance 
which  you  desire  to  cover. 

Q.  2.  Can  I  use  it  in  connection  with  an 
open  or  closed  core  transformer,  or  is  the 
spark  coil  the  only  way? 

A.  2.  Yes,  providing  that  a  mechanical 
vibrator  is  used  in  conjunction  with  it  when 
using  an  open  core  transformer.  This  can 
either  be  directly  operated  by  the  transfor- 
mer core  or  else  you  may  employ  an  inde- 
pendent vibrator.  We  would  advise  that 
you  employ  a  spark  coil,  say  about  a  4- 
inch  coil,  and  you  will  find  that  it  will  give 
better  service  than  if  an  open  core  trans- 
former is  used. 

Q.  3.  Could  I  not  use  the  combined 
voltage  of  the  generator  and  battery  and 
have  sufficient  voltage? 

A.  3.  Yes ;  but  the  voltage  will  not  be 
sufficient  or  of  the  correct  character  to  op- 
erate a  transformer  without  a  mechanical 
interrupter. 

UNDAMPED  WAVE  RECEPTION. 

(761.)  Walter  B.  Clifford,  Worcester, 
Mass.,  writes: 

Q.  1.  Is  it  possible  to  employ  a  mineral 
detector  in  place  of  an  Audion  detector 
for  receiving  undamped  signals?  If  so, 
what  connection  of  instruments  should  be 
used? 

A.  1.  It  is  possible  to  receive  undamped 
waves  by  employing  a  crystal  detector  pro- 
viding a  tikker  of  some  kind  is  employed 
in  the  detector  circuit.     The  diagram  of 


connections  is  given  herewith  and  shows  a 
circuit  breaker  or  tikker  being  used. 

Q.  2.  Will  you  please  publish  a  diagram 
of  the  connection  of  the  instruments  used 
in  a  simple  inductive  wireless  telephone 
circuit  ? 

A.  2.  Our  diagram  gives  the  connection 
of  a  simple  radio  telephone  employing  the 
induction  principle.  The  transmitting  coil 
should  be  five  feet  in  diameter  while  the 
receiving  coil  is  four  feet.  Each  coil  is 
wound  with  one  hundred  turns  of  annun- 
ciator wire. 

Q.  3.  Is  it  advisable  to  employ  a  helix 
with  a  one  inch  spark  coil? 

A.  3.  If  you  desire  to  bring  your  trans- 
mitting wave  length  to  some  definite  value, 
you  should  employ  a  helix. 


V.C.  Cdntfcts 


TifAerl  o 


0*76,  0 


Proper    Connection    for    "Tikker"    Type  of 
Radio  Receiving  Circuit  for  Undamped  Wave 
Signals. 


Transmuting  Coii 
Receiving  Coil  vmsmmf 


Telephone 


induction  Coil 


Hook-up  for  Inductive  Wireless  'Phone. 


SELENIUM. 

(762.)  E.  W.  Donaldson,  Fairmont,  W. 
Va.,  wishes  to  know : 

Q.  1.  In  what  quantities  is  the  element 
selenium  available? 

A.  1.  This  element  can  be  supplied  to 
you  in  any  quantities  desired,  and  it  may 
be  procured  from  The  Electro  Importing 
Co.,  Kew  York,  N.Y.,  or  Electro-Set  Co., 
of  Cleveland,  Ohio. 

Q.  2.  Does  it  remain  constant  in  its 
conductivity  under  periods  of  use,  say 
three  or  four  seconds  several  times  a  day 
or  longer? 

A.  2.  The  conductivity  of  selenium  crys- 
tals under  the  influence  of  light  is  not  con- 
stant but  variable.  The  variation  of  con- 
ductivity of  lenium  depends  upon  many 
factors,  such  as  the  applied  voltage,  source 
and  intensity  of  illumination  and  chemical 
purity  of  the  selenium  crystal. 


MOTOR  STARTING  QUERY. 

(763.)   J.  Adler,  New  York,  N.Y.,  asks: 
Q.  1.  How    should   a  shunt    motor  be 
started  ? 

A.  1.  First,  the  field  current  is  applied 
at  full  line  voltage;  then  the  armature  cur- 
rent is  thrown  on  at  much  less  than  line 
voltage,  the  voltage  being  held  down  or 
controlled  by  resistance  in  a  starting  box; 
as  the  motor  comes  up  to  normal  speed,  re- 
sistance is  cut  out  step  by  step  until  full 
line  voltage  is  imprest  on  the  armature. 
This  is  all  accomplished  by  one  motion  of 
the  handle  of  a  well-designed  rheostat  or 
starting  box.  Most  starting  boxes  are  so 
arranged  with  a  magnetic  release  or  other- 
wise, that  the  motor  is  automatically  cut 
out  of  the  circuit  in  case  the  line  voltage 
should,  thru  any  accident,  be  shut  off. 

Q.  2.  What  is  an  accumulatively  wound 
compound  motor? 

A.  2.  It  is  a  motor  whose  series  and 
shunt  field  windings  are  in  the  same  direc- 
tion and  therefore  as  the  load  comes  on 
the  series  field  assists  the  shunt  field  and 
a  stronger  magnetization  and  increased 
torque,  with  slightly  reduced  speed,  results. 

STORAGE  BATTERIES. 

(764.)  Harry  Blumenthal,  Harrison, 
N.J.,  wants  to  know : 

Q.  1.  To  what  use  is  the  storage  bat- 
tery sometimes  put  in  electric  lighting  or 
power  stations? 

A.  1.  To  carry  the  peak  of  the  load,  i.e., 
that  excessive  portion  of  the  load  which, 
for  instance,  in  electric  lighting  stations 
has  to  be  carried  only  for  two  or  three 
hours  a  day.  They  carry  the  entire  load 
at  minimum  hours;  to  act  as  equalizers  or 
reservoir. 

Q.  2.  How  do  Faure  plates  compare  with 
those  of  the  Plante  type? 

A.  2.  They  are  usually  lighter  and  have 
a  higher  capacity,  but  have  a  tendency  to 
shed  the  material  from  the  grid,  thus  ma- 
king the  battery  useless. 

Q.  3.  At  what  density  is  the  resistance 
of  dilute  sulfuric  acid  at  a  minimum? 

A.  3.  At  1.260  Baume. 


MOTOR  ACTION. 

(765.)  L.  Askel,  Detroit,  Mich.,  asks: 

Q.  1.  Why  does  the  speed  of  a  shunt 
motor  increase  when  the  position  of  the 
brushes  is  off  neutral? 

A.  1.  When  the  brushes  are  shifted  from 
the  neutral  plane,  the  reverse  voltage  be- 
tween the  brushes  is  decreased,  the  speed 
remaining  unchanged.  Accordingly,  the 
pressure  in  the  supply  mains  forces  an  in- 
creased current  thru  the  armature,  thus 
producing  an  increased  armature  pull, 
which  causes  the  speed  to  increase  until 
the  reverse  voltage  reaches  a  value  suffi- 
ciently large  to  reduce  the  current  to  the 
value  required  to  supply  the  necessary  driv- 
ing torque. 

Q.  2.  Can  you  tell  me  the  existing  mu- 
tual relations  of  motor  torque  and  speed? 

A.  2.  The  character  of  the  work  to  be 
done  not  only  determines  the  condition  of 
the  motor  torque  and  speed  required,  but 
also  the  suitability  of  a  particular  type  of 
{Continued  on  page  52) 


May,  1917 


THE  ELECTRICAL  EXPERIMENTER 


5i 


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Stamps 
Brings 
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SHORT  WAVE  REGENERATIVE  SET 
Every  worth  while  feature  is  incorporated  in  this  Regenerative  Set.  Initial 
tests  in  our  laboratory  and  at  thelocal  Scott  High  School  brought  in  with  re- 
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52 


THE  ELECTRICAL  EXPERIMENTER 


May,  1917 


EXPERIMENTAL  CHEMISTRY. 

(Continued  from  page  43) 
EXPERIMENT  NO.  52 

Wash  the  test  tubes,  add  fresh  acid,  and 
drop  a  piece  of  Calcium  carbonat  (marble) 
into  each  tube  successively.  Proceed  in  the 
same  manner  as  with  the  metals  in  the 
foregoing  experiment,  only  in  this  case  the 
gas  must  be  tested  not  only  with  a  burning 
match,  but  as  follows :  Dip  a  clean  glass 
rod  into  lime-water,  and  hold  it  in  the 
escaping  gas.  (The  escaping  ^as  is  Carbon 
dioxid) . 

The  results  of  these  experiments  are 
characteristic  of  all  acids,  and  substances 
acting  thus  are  said  to  be  Acid,  or  to  have 
Acid  properties,  or  to  have  an  Acid  re- 
action. 

The  test  with  litmus  paper  is  true  only 
for  litmus,  but  it  is  a  striking,  simple  test 
for  acids,  and  should  be  remembered,  that 
acids  turn  blue  litmus  red. 
BASES— 

Bases  in  chemistry,  includes  those  Hy- 
droxids  of  metals  which  neutralize  acids 
by  partly  or  entirely  replacing  their  hy- 
drogen, thereby  yielding  compounds  called 
salts. 

Bases  are  in  a  few  cases  soluble,  in  most 
cases  insoluble.  When  soluble  in  water 
they  turn  red  litmus  blue,  and  possess  caus- 
tic properties. 

Bases  usually  have  an  acrid  or  bitter 
taste. 

Since  every  base  contains  Hydrogen  and 
Oxygen  they  are  sometimes  called  Hy- 
droxids.  Hydrat  is  sometimes  used  as  a 
synonym  of  Hydroxid,  while  the  term  Al- 
kali, emphasizes  general  properties  rather 
than  suggests  specific  composition.  Hy- 
droxids  are  distinguished  from  each  other 
by  placing  the  name  of  the  metal  before 
the  word  Hydroxid,  as,  Sodium  Hydroxid, 
Potassium  Hydroxid. 

Not  all  bases  contain  the  same  number 
of  hydroxyl  groups.  Therefore,  bases, 
like  acids,  may  form  one  or  more  salts. 
This  power  is  called  Acidity.  Bases  are 
called,  Monacid,  Diacid,  Triacid  bases,  etc., 
according  to  the  number  of  replaceable  hy- 
droxyl groups  present  in  the  molecule. 
Calcium  hydroxid  (Ca[OH]2)  is  a  diacid 
base,  and  Aluminum  hydroxid  (Al[OH]3) 
is  a  triacid  base. 

A  base  contains  a  metallic  element,  as, 
Potassium  (K),  Sodium  (Na),  Copper 
(Cu),  Calcium  (Ca),  Iron  (Fe),  Zinc  (Zn), 
together  with  Hydrogen  and  Oxygen. 

Below  are  bases : 

Potassium  Hvdroxid  KOH 
Sodium  Hydroxid  Na[OH] 
Calcium  Hydroxid  Ca[OH]2 
Ferric  Hydroxid  Fe  [OH], 

Copper  Hydroxid  Cu  [OH], 

Zinc  Hydroxid  Zn[OH]2 
Ammonium  Hydroxid  NH4OH 
Aluminum  Hydroxid  Al[OH]3_ 
When  a  salt  is   formed  from  an  acid 
and  base,  the  metal  of  the  base  enters  into 
the  acid  in  place  of  the  hydrogen,  and  the 
hydrogen  combines  with  the  Hydrogen  and 
Oxygen  of  the  base  to  form  water  (H20). 

HNO3    +    KOH     =    KNO3    +  H2O 
Nitric  acid     Potassium     Potassium  Water 
Hvdroxid  Nitrat 
(Acid)     +     "(Base)     =      (Salt)     +  (Water) 

The  same  is  true  of  the  following: 

H2SO4     +    2NaOH  =  Na2S04  +  2H2O 
Sulfuric  acid       Sodium      Sodium  Water 
Hydroxid  Sulphat 

EXPERIMENT  NO.  53 

Pour  5  CC.  of  Ammonium  Hvdroxid 
(NH4OH),  5  cc.  of  Sodium  Hydroxid 
(NaOH),  5  cc.  of  Potassium  Hydroxid 
(KOH),  into  separate  test  tubes  and  place 
in  a  test  tube  rack.  Add  about  5  cc.  of 
water  to  each,  and  shake  the  contents. 

Place  a  piece  of  both  red  and  blue  lit- 
mus paper  (or  litmus  solution^  may  be 
used,  a  drop  being  sufficient)  into  each 
tube  and  note  the  result. 


It  will  be  noticed  upon  the  introduction 
of  the  litmus,  that  the  blue  paper  (or  solu- 
tion) is  unaffected,  while  the  red  paper  (or 
solution)  has  turned  blue.  This  is  a  char- 
acteristic of  all  bases,  and  is  employed  as 
a  test  for  them. 

After  testing  as  above  pour  the  contents 
out  and  rinse  the  tubes. 

If  we  arrange  the  symbols  of  the  above 
bases  we  have : 

NH4OH 
NaOH 
and 
KOH 

It  will  be  noticed  that  the  OH  or  hy- 
droxyl is  contained  in  all  three.  It  will 
also  be  noted  that  the  remaining  portion, 
namely,  NH4,  Na,  and  K,  are  metallic. 
That  the  bases  turn  red  litmus  blue. 
SALTS 

A  salt  is  a  substance  composed  of  a  met- 
al or  positive  radical  united  with  a  non- 
metal  or  negative  radical.  These  com- 
pounds in  some  respects  resemble  common 
salt,  that  are  formed  by  the  replacement 
of  the  hydrogen  of  acids  by  metallic  radi- 
cals, both  simple  and  complex.  They  may 
be  classified  as  Normal,  Acid,  and  Basic 
salts,  according  to  whether  the  hydrogen 
of  the  acid  is  completely  or  only  partially 
replaced  in  the  first  two  cases,  or  whether 
the  Oxygen  or  hydroxyl  groups  of  a  base 
are  only  partially  neutralized  by  an  acid  in 
the  last. 

A  salt  generally  has  an  acrid  taste. 
Some  salts  are  soluble,  some  insoluble. 
Salts  may  be  prepared  by  one  of  the  fol- 
lowing types. 

1.  Action  of  a  metal  on  an  acid.  This, 
besides  forming  the  salt,  usually  sets  free 
hydrogen  or  some  decomposition  product 
of  the  acid  produced  by  its  action.  For 
example,  Zinc  sulphat  and  copper  nitrat 
are  produced  by  the  reactions; 

Zn  +  H2SO4  =  ZnS04  +  H2 

Zinc    Sulfuric      Zinc  Hydrogen 
Acid  Sulphat 

and, 

3Cu  +  8HNO3  =  3Cu(N03)2  +     8NO3  4H2O 

Copper     Nitric           Copper  Nitrogen  Water 

Acid            Nitrate  Monoxide 

2.  Neutralization  of  an  acid  by  a  base, 
the  latter  being  an  oxid,  hydroxid,  am- 
monia, or  similar  substance.  Thus  lead 
chlorid,  sodium  acetat,  and  ammonium  ni- 
trat are  produced  by  the  reactions : 

PbO     +       2HC1        =  PbCl2  +  H2O 
Lead  Oxid     Hydrochloric       Lead  Water 
Acid  Chlorid 

NaOH  +  CH3COOH  =  H2O  +  CH3  COONa 
Sodium     Acetic  Acid      Water  Sodium 
Hydroxid  Acetat 

NH3    +      HNO3     =  NH4NO3 
Ammonia      Nitric  Acid     Ammonium  Nitrat 

3.  By  the  double  exchange  between  two 
salts  or  an  acid  and  salt,  as  in  the  prep- 
aration of  Barium  sulphat  and  Sodium 
hydrogen  sulphat  by  the  reactions : 

Ba  CI2  +  Na2S04  =  BaSOs  +  2NaCl 
Barium      Sodium      Barium  Sodium 
Chlorid      Sulphat      Sulphat  Chlorid 
NaCl  +  H2SO4  =         NaHS04      +  HC1 
Sodium     Sulfuric      Sodium  Hydrogen  Hydrochloric 
Chlorid        Acid  Sulphat  Acid 

Other  reactions  forming  salts  are : — 

Na20     +   H2SO4  =       Na2S04       +  H2O 
Sodium  Oxid     Suit  uric     Sodium  Sulphat  Water 
Acid 

Zn  +      H2S04      =     ZnS04      +  H2 
Zinc     Sulfuric  Acid    Zinc  Sulphat  Hydrogen 
CaC03  +       2HC1      =    CaClz  +  CO2   +  H2O 
Cplcium     Hydrochloric    Calcium    Carbon  Water 
Carbonat  Acid  Chlorid  Dioxid 

When  a  salt  is  formed  from  an  acid  and 
(Continued  on  page  78) 


tors  and  these  require  the  following  con- 
ditions of  torque  and  speed:  (a)  Constant 
torque  at  variable  speed;  (b)  variable 
torque  at  constant  speed,  and  (c)  variable' 
torque  at  variable  speed. 

Q.  3.  What  is  the  object  of  the  commu- 
tating  field  produced  by  the  interpoles  of 
a  motor? 

A.  3.  Its  object  is  to  assist  commutation, 
that  is  to  help  reverse  the  current  in  each 
coil  while  short-circuited  by  the  brush,  and 
thus  reduce  sparking. 

WIRING  QUERIES. 

(766.)  W.  Holsen,  Buffalo,  N.Y.,  de- 
sires to  know : 

Q.  1.  What  are  the  disadvantages  of 
open  wiring? 

A.  1.  The  wiring  is  not  sufficiently  pro- 
tected from  moisture .  and  the  effects  of 
fire  which  will  destroy  the  insulation  of 
the  wires;  it  is  also  liable  to  mechanical 
injury. 

Q.  2.  How  far  apart  should  the  wires 
be  placed  if  open  wiring  is  used? 

A.  2.  When  installed  in  dry  places  and 
for  pressures  below  300  volts,  the  insulators 
should  separate  the  wires  2J/2  inches  from 
each  other  and  ^2  inch  from  the  surface 
over  which  they  pass.  For  voltages  from 
300  to  500  volts  the  wires  should  be  sep- 
arated four  inches  from  each  other  and 
one  inch  from  the  surface  along  which 
they  pass.  When  wiring  in  damp  places 
or  over  metal  ceilings  the  wires  should  be 
at  least  one  inch  from  the  surface. 

Q.  3.  How  should  wires  be  protected 
when  run  vertically  on  walls? 

A.  3.  They  should  be  boxed  in  or  run  in 
a  pipe.  The  .covering  should  extend  six 
feet  above  the  floor. 


QUESTION  BOX. 

(Continued  from  page  50) 
motor  for  a  given  service.    There  are  three 
general  classes  of  work  performed  by  mo- 


RADIO-TELEPHONY. 

(767.)  Marion  L.  Brown,  Oroille,  in- 
quires : 

Q.  1.  Please  advise  me  as  to  whether  the 
hook-up  which  I  send  you  will  work  on  110 
volts,  alternating  current,  using  an  ordi- 
nary telephone  transmitter.  If  this  hook- 
up will  not  work,  please  send  me  a  simple 
hook-up  that  will  work  on  110  volts  A.C., 
using  telephone  transmitter  and  one  that  is 
inexpensive  to  make. 

A.  1.  The  diagram  of  connections  which 
you  submit  will  not  work  satisfactorily  and 
wish  to  inform  you  that  in  order  to  make 
a  radiophone  operate  on  A.C.  that  you  con- 
nect the  transmitter  in  series  with  the  pri- 
mary of  the  oscillation  transformer.  An 
ordinary  microphone  as  employed  in  tele- 
phone practise  will  handle  not  more  than 
one-half  ampere,  so  that  it  will  be  neces- 
sary for  you  to  confine  your  power  below 
J/2  KW.  If  more  power  is  to  be  controlled, 
then  several  microphone  transmitters  will 
be  required  in  parallel  and  their  mouth- 
pieces brought  to  a  single  mouthpiece. 

WAVE  LENGTH  PROBLEM. 

(768.)  Wm.  H.  Mansfield,  Jr.,  Putnam, 
Conn.,  desires  : 

Q.  1.  What  is  the  wave  length  of  an 
aerial  144  feet  long,  50  feet  high  and  a 
70  foot  lead-in?    It  is  a  three-wire  aerial. 

A.  1.  The  wave  length  of  your  aerial  is 
320  meters. 

Q.  2.  What  is  the  wave  length  of  an 
aerial  6  wires  30  feet  high  and  35  feet 
long? 

A.  2.  The  wave  length  of  this  antenna 
is  110  meters. 

Q.  3.  What  is  the  smallest  sized  spark 
coil  an  Oscillation  Transformer  can  be 
used  on  efficiently? 

A.  3.  This  will  depend  upon  the  antenna 
system  and  the  wave  length  which  you 
desire  to  tune.  It  may  be  said  in  general 
that  two  turns  will  be  the  least  number 
that  the  coil  will  require.  The  primary 
winding  has  less  turns  than  those  of  the 
secondary. 

(Continued  on  page  54) 


May,  1917 


THE  ELECTRICAL  EXPERIMENTER 


53 


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Being  a  user  of  an  Audion  Bulb  and  having  firmly,  after  due  test  and  consideration  of  "mineral 
detectors,"  discarded  them  as  unstable  and  unreliable  and  very  inconvenient,  being  hard  to  keep 
in  adjustment,  I  was  very  skeptical  as  to  Lenzite,  but  glad  to  make  the  test  and  more  than  pleased 
that  I  did  so. 

I  found  that  the  reception  of  signals  with  Lenzite  as  a  detector  quite  beyond  any  hopes  that 
I  may  have  had. 

Inasmuch  as  the  mineral  in  question  (Lenzite)  seems  to  be  "sensitive"  nearly  all  over  its  sur- 
face on  all  sides,  which  is  a  very  great  advantage  as  it  makes  it  almost  as  easy 
to  keep  in  adjustment  as  an  audion,  and  brings  in  the  signals,  when  proper 
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add  I  was  greatly  surprised  as  it,  without  any  question,  has  given  me  far 
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This  detector  does  not  employ  or  incorporate  an  evacuated  vessel  contain- 
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54 


THE  ELECTRICAL  EXPERIMENTER 


May,  1917 


THE  STORY  OF  FLASHLIGHT 
MAKING. 

All  of  us  have  undoubtedly  found  the 
electric  flashlight  extremely  useful  at  some 
time  or  other,  but  very  few  people  are 
privileged  to  know  just  how  the  flashlight 
is  made.  One  of  the  leading  manufactur- 
ers of  these  useful  devices  recently  con- 


1 


CtfNfll* 


Interesting    Exhibit    Which    Tells   the  Story 
light    Making    Grafically.       Every  Important 
Manufacture  Is  Clearly  Shown. 

structed  a  display  board  containing  the  es- 
sential parts  constituting  a  complete  flash- 
light, the  appearance  of  which  may  be 
judged  from  the  accompanying  illustration. 
It  was  used  by  the  bureau  of  visual  instruc- 
tion of  the  University  of  California  as  a 
traveling  industrial  exhibit.  The  upper  two 
rows  represent  the  various  stages  of  man- 
ufacture thru  which  a  coat  pocket  style 
flashlight  passes.  The  lower  three  rows 
show  the  progressive  steps  in  the  making 
of  a  tubular  flashlight.  A  similar  visual 
exhibit  prepared  by  the  same  concern 
showed  in  a  striking  and  educational  man- 
ner, the  various  stages  of  flashlight  battery 
make-up ;  from  the  zinc  plate  to  the  as- 
sembled battery,  consisting  of  two  or  more 
cells  nestling  comfortably  in  its  paper  car- 
ton. 


The  Detroit  Edison  Company  'has  made 
a  number  of  tests  with  different  methods 
of  electrically  heating  cars  stored  in  un- 
heated  garages.  Various  means  of  heating 
insulated  and  uninsulated  garages  have 
been  tried  and  experiments  made  with 
nearly  all  of  the  heaters  sold  for  heating 
the  engine  itself.  The  results  of  these  tests 
are  now  being  worked  up,  and  they  will 
probably  be  presented  in  a  paper  at  one 
of  the  conventions  during  the  summer. 


control  the  machine  automatically  in  case 
the  pilot  is  unable  to  get  positive  control 
of  the  machine. 

The  only  real  solution  so  far  to  this  prob- 
lem involves  the  use  of  the  gyroscope  and 
the  work  done  bv  Mr.  Elmer  Sperry  in  this 
line  gives  much  light  to  the  solution.  Fig. 
5  illustrates  the  Sperry  automatic  pilot 
which  relieves  the  pilot  of  the 
labor  and  drudgery  in  operating 
the  controls  of  his  machine.  In 
the  military  aeroplane  it  renders 
it  possible  for  the  pilot  to  ful- 
fill the  duties  of  both  pilot  and 
observer.  When  dropping  bombs 
it  enables  the  pilot  to  bring  the 
aeroplane  laterally  over  the  tar- 
get, makes  a  reference  plane  of 
the  aeroplane,  which  greatly  in- 
creases the  accuracy  of  bomb 
dropping,  and  creates  a  steady 
platform  from  which  to  fire  and 
drop  bombs. 

The  equipment  consists  prin- 
cipally of  three  units — the  gener- 
ator, servo  motor  and  gyro  unit 
■ — which  may  be  likened  respec- 
tively to  the  heart,  muscles  and 
brain  of  the  human  pilot. 

The  gyro  unit  which  is  placed 
in  a  metal  case  and  shown  in 
the  background  utilizes  the  gyro- 
scopic effect  of  the  four  rotating 
gyros  which  it  contains,  in  main- 
taining a  horizontal  reference 
plane.  Any  departure  of  the 
aeroplane  for  its  set  relation  to 
this  gyroscopic  reference  plane 
causes  an  electrical  contact  to  be 
made  which  completes  a  circuit 
to  one  of  the  magnetic  clutches 
in  the  servo  motor.  The  case  is 
equipt  with  a  glass  window  to 
enable  the  operator  to  note  the 
joperation  of  the  four  gyros.  The  power 
generated  in  the  servo  motor  air  turbine 
is  now  transmitted  thru  the  engaged  clutch 
to  one  of  the  drums  over  which  the  control 
wire  passes. 

The  generator  which  is  seen  in  the  fore- 
ground of  the  photograph  supplies  alter- 
nating current  for  driving  the  gyros  and 
direct  current  for  the  servo  motor  clutches. 
It  consists  of  a  double  armature,  one  wind- 
ing of  which  is  tilized  for  the  generation 
of  the  alternating  current  and  the  other 
for  direct  current.  It  is  driven  by  means 
of  an  aluminum  propeller  driven  by  the  air 
current.  The  four  leads  are  run  from  the 
rear  to  the  generator. 

By  means  of  a  special  set  of  clutches  on 
the  gyro  unit,  the  operator  can  set  the 
aeroplane  to  any  position  relative  to  the 
horizontal  which  he  may  desire,  by  simply 
pressing  a  button  located  conveniently  on 
the  manual  control  and  moving  his  con- 
trols as  tho  no  automatic  nilot  were  in- 
stalled on  the  machine.  When  the  aero- 
plane reaches  the  desired  altitude,  the  but- 
ton is  released  and  control  is  again  given 
over  to  the  automatic  pilot,  which  will  hold 
the  machine  in  that  altitude  until  altered 
by  the  operator. 

Complete  and  unhampered  control  may 
be  instantly  resumed  at  any  time  by  press- 
ing on  the  push  button  on  the  controls. 


of  Flash- 
Stage  of 


ELECTRIFYING  THE  AEROPLANE. 

(Continued  from  page  7) 
ward  the  exact  amount  which  is  likewise 
shown  in  degrees.   The  scale  is  coated  with 
Radium  paint  so  that  it  is  visible  at  night 
by  its  own  light. 

One  of  the  greatest  problems  of  aero- 
nautical engineering  is  that  of  making  the 
aeroplane  as  safe  as  possible.  Thousands 
and  even  hundreds  of  thousands  of  dollars 
have  been  spent  in  this  direction  and  the 
nearest  conclusion  to  this  problem  is  the 
adoption  of  some  automatic  pilot,  which  will 


WAR  CONFERENCE  WITH  TELE- 
GRAPH AND  TELEPHONE 
OFFICIALS. 

Messrs.  Theo.  N.  Vail,  president  of  the 
American  Telephone  and  Telegraph  Com- 
pany; Newcomb  Carlton,  president  of  the 
Western  Union  Telegraph  Company; 
Charles  P.  Bruch,  vice-president  of  the 
Postal  Telegraph-Cable  Company;  F.  B. 
McKinnon,  vice-president  of  the  United 
States  Independent  Telephone  Association, 
and  N.  C.  Kingsbury,  vice-president  of  the 
American  Telephone  and  Telegraph  Com- 


pany, were  in  conference  with  war  depart- 
ment officials  at  Washington  on  March  19 
to  perfect  plans  to  insure  the  government 
rapid  and  efficient  wire  communication. 

QUESTION  BOX. 

(Continued  from  page  52) 
WAVE  MOTORS. 

(769.)  G.  H.  G.,  Detroit,  Mich.,  in- 
quires as  to  the  efficiency  and  practicability 
of  wave  motors : 

A.  1.  We  do  not  know  just  now  of  any 
successful  installation  of  such  wave  power 
plants  as  described  in  the  February  issue  of 
this  journal  and  while  the  initial  cost  of 
installing  such  a  plant  is  not  so  prohibi- 
tive, there  has  always  been  more  or  less 
prejudice  against  them,  owing  to  the  fact 
that  the  power  developed  is  so  irregular. 

There  have  been  a  number  of  attempts 
made  by  inventors  to  overcome  this  dif- 
ficulty, but  the  fact  of  the  matter  remains 
that  we  have  yet  to  see  a  practical  instal- 
lation of  a  wave  motor  on  any  large  scale. 
The  proposition  to  our  mind  seems  to 
possess  many  practical  and  economic  fea- 
tures, and  it  seems  very  likely  that  in  later 
years  a  future  generation  may  see  the  ad- 
aptation of  wave  motors  to  a  very  large 
extent. 

You  may  obtain  copies  of  the  patents 
issued  on  this  interesting  subject  by  com- 
municating with  the  U.  S.  Patent  Office, 
Washington,  D.C.,  and  with  these  before 
you,  you  will  be  in  a  better  position  to  see 
just  what  has  been  done  and  what  has 
been  proposed  in  solving  this  problem. 

CONDENSER  IN  AERIAL  CIRCUIT. 

(770.)  Anthony  S.  Detrees,  Hartford, 
Mich.,  asks : 

Q.  1.  Can  a  series  condenser  be  used 
successfully  in  connection  with  a  trans- 
mitter, to  reduce  the  natural  wave  length 
of  an  aerial  from  325  to  160  meters? 

A.  1.  Yes. 

Q.  2.  Would  such  an  arrangement  re- 
sult in  low  efficiency  in  transmitting? 

A.  2.  The  addition  of  a  condenser  in 
series  with  the  antenna  circuit  increases 
considerably  the  amount  of  losses  and  at 
the  same  time  increases  the  decrement  due 
to  an  increase  in  antenna  resistance  by  the 
series  condenser. 

12  VOLT  LIGHTING  PLANT. 

(771.)  U.  J.  Grant,  Apple  Creek,  Ohio, 
writes : 


Wiring  Diagram  for  32  Volt  Lighting  Plant. 


Amp. 


Volts 


Fie/dcoih 

w  Arm  I 
U-W-J7  i 

0/4/r.Cir/nst 


COll 


6ra/ndedon  ul 
90s  engine  frame 


To  second 
bat.  if  used 


0771 


Lamps 

Sm'tcbes 

L°/?fi<tJ  rubb.  cor 
wire  on  up  to  so  -40 
ft.  circuits  Forlongei 
circuits  use  iorger 
iv ires. 

© 


May,  1917 


THE  ELECTRICAL  EXPERIMENTER 


55 


Q.  1.  I  would  like  to  have  a  wiring  dia- 
gram for  a  32  volt  isolated  lighting  plant 
with  the  following  apparatus:  Y\  K.W. 
generator,  32  volt  60  ampere-hour  storage 
battery,  switchboard  with  voltmeter,  zero- 
center  ammeter  showing  charge  and  dis- 
charge, circuit-breaker,  regulating  rheo- 
stat for  generator  and  proper  fuses  and 
switches. 

A.  1.  The  accompanying  wiring  dia- 
gram gives  the  connections  of  a  complete 
32  volt  lighting  plant. 

Q.  2.  What  is  the  wave  length  of  my 
inverted  "L"  type  aerial,  composed  of  one 
wire  400  feet  long,  70  feet  high  at  one  end 
and  40  feet  at  the  other,  with  30  feet  lead- 
in  and  20  feet  ground  (No.  4  copper 
wire)  ? 

A.  2.  The  wave  length  of  your  antenna 
is  617  meters. 


Ohio, 


DYNAMO  QUERIES. 

(772.)    George   Ledly,  Cleveland, 
desires  to  know : 

Q.  1.  Can  a  12  volt,  9  ampere  dynamo, 
such  as  the  "Electro"  Hercules  charge  suc- 
cessfully two  6  volt,  100  ampere-hour  stor- 
age batteries  in  series? 

A.  1.  Yes.  They  should  be  connected 
in  parallel,  however. 

Q.  2.  Can  a  25  volt,  4  ampere  dvnamo 
be  run  in  series  with  four  6  volt  100  am- 
pere storage  batteries  to  produce  50  volts? 

A.  2.  Yes,  providing  that  the  batteries 
are  fully  charged.  It  would  be  advisable 
to  employ  an  underload  circuit  breaker  in 
the  storage  battery  side  so  that  they  will 
be  disconnected  when  they  are  in  a  dis- 
charged condition,  thus  preventing  the 
charging  of  the  battery  by  the  dynamo  in 
an  opposite  direction,  in  this  way  prevent- 
ing the  plates  from  being  ruined. 


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THE  ELECTRICAL  EXPERIMENTER 


May,  1917 


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INDIRECT  LIGHTING. 

(773.)  J.  Andrews,  San  Francisco,  Cal., 
inquires : 

Q.  1.  What  is  meant  by  indirect  lighting 
and  what  are  its  characteristics? 

A.  1.  Indirect  lighting  as  the  name  sig- 
nifies is  illumination  in  which  the  light 
comes  to  the  working  plane  indirectly.  The 
light  of  the  lamp  is  directed  at  the  ceiling 
by  suitable  reflector  appliances,  and  from 
there  is  diffusely  reflected  into  the  room, 
making  the  ceiling  a  secondary  light  source. 

The  enlarged  low  brilliancy  source  of 
light,  the  ceiling,  produces  a  highly  uni- 
form and  diffuse  illumination,  free  from 
glare.  Shadows  are  softened  and  merge 
very  gradually  into  the  brighter  areas. 
There  is  practically  no  glare  or  reflection 
from  glossy  surfaces.  Recent  tests  ap- 
parently confirm  the  general  belief  that 
indirect  lighting  requires  minimum  inten- 
sity of  illumination  for  comfortable  vision 
and  causes  very  low  fatigue  of  the  eye 
as  a  result  of  several  hours'  work. 

Q.  2.  What  are  the  chief  considerations 
in  planning  an  adequate  lighting  installa- 
tion ? 

A.  2.  Planning  a  lighting  installation  is 
a  complex  problem,  requiring  due  consid- 
eration of  a  number  of  factors.  The  in- 
tensity of  illumination  must  be  ample  for 
clear  comfortable  vision;  the  distribution 
must  be  nearly  uniform  over  the  working 
plane.  The  color  of  the  light  must  be 
suitable  for  the  class  of  service,  and  the 
taste  of  the  individual  and  the  diffusion 
must  be  satisfactory  for  the  class  of  serv- 
ice. The  sources  of  light  must  be  placed 
well  above  the  range  of  vision' and  the  in- 
trinsic brilliancy  reduced  by  the  use  of  dif- 
fusing" glassware  or  indirect  reflector  equip- 
ment; shadows  on  the  working  plane  must 
be  softened  and  toned  down  so  as  not  to 
be  too  abrupt  and  for  drafting  rooms, 
operating  rooms,  etc.,  practically  elimina- 
ted; objects  capable  of  high  specular  re- 
flection (glossy  objects)  should  be  re- 
moved from  the  range  of  vision. 


POWER  HOUSE  PROPOSITION. 

(774.)  Paul  Wheadon,  New  Brunswick, 
Ga.,  wants : 

Q.  1.  What  types  of  power  houses  are 
used  by  large  factories  as  we  desire  to 
equip  our  plant  with  an  electric  equipment? 

A.  1.  There  are  several  types  in  com- 
mon use.  Some  factories  use  125  volts 
direct  current.  However,  220  volts  direct 
current  is  popular  araon?  steel  mills.  The 
larger  ones  sometimes  use  500  volts.  Al- 
ternating current  is  largely  used,  induc- 
tion motors  being  employed  to  drive  ma- 
chines or  line  shafting.  Cranes  are  most- 
ly operated  by  direct  current,  altho  alter- 
nating current  may  be  used  for  this  pur- 
pose. 

Q.  2.  What  arrangement  of  excitation 
is  customary? 

A.  2.  Direct  current  generators  are  us- 
ually self-excited.  Alternators  usually  re- 
quire separate  excitation  which  is  had 
from  a  relatively  small  direct  current  gen- 
erator. It  is  preferable  that  the  exciters 
should  have  a  separate  prime  mover  if 
space  economy  is  possible,  tho  many  ex- 
citers are  driven  by  the  same  engine  that 
drives  the  main  generator. 

Q.  3.  What  considerations  determine  the 
voltage  of  a  transmission  line? 

A.  3.  The  voltage  of  a  transmission  line 
is  found  by  a  careful  study  of  the  ad- 
vantages of  very  high  voltages  in  permit- 
ting the  transmission  of  a  large  amount 
of  power  on  a  small  conductor;  the  ad- 
vantages of  lower  voltages  because  of 
the  greater  ease  of  insulating,  the  dis- 
tance to  be  covered  and  the  nature  of 
the  country  thru  which  the  line  is  to  be 
run.  Due  consideration  is  also  given  to 
the  first  cost  of  power.    If  it  is  obtained 


from  water  power  or  from  very  cheap 
coal,  it  may  be  best  to  design  for  rela- 
tively high  line  losses.  If  coal  is  trans- 
ported a  long  distance,  it  is  therefore  ex- 
pensive, and  the  line  must  be  designed  for 
low  losses.  Each  case  requires  special 
study  by  experts. 

INDOOR  AERIAL. 

(775.)  Mr.  Shane,  Grand  Rapids,  Mich., 
says : 

Q.  1.  Kindly  let  me  know  what  an  in- 
door aerial  is  made  up  of  and  the  dis- 
tance one  can  hear  with  the  same. 

A.  1.  An  indoor  aerial  is  nothing  more 
than  an  ordinary  antenna  which  is  erected 
indoors.  The  distance  which  one  can  re- 
ceive with  such  an  antenna  depends  en- 
tirely upon  the  sensitivity  of  the  instru- 
ments used  with  this  type  of  aerial. 

Q.  2.  Kindly  let  me  know  where  I  can 
get  full  set  of  rules  in  reference  to  size 
and  power  receiving  and  sending  set  the 
Government  will  allow  one  to  have  and 
what  is  necessary  to  pass  examination  to 
allow  a  large  set  to  be  erected? 

A.  2.  We  advise  you  to  communicate 
with  the  Radio  Inspector  of  your  district 
who  will  give  you  all  the  information  you 
desire. 

Q.  3.  Kindly  let  me  know  if  it  is  al- 
ways necessary  to  have  a  wire  run  all 
the  way  down  to  the  earth  to  make  a 
ground  and  if  one  is  in  a  hotel  on  the 
ninth  floor  or  higher  up,  how  he  can  make 
a  ground  without  having  to  let  a  wire 
down  to  the  street  at  the  same  time  want- 
ing it  to  be  safe  from  all  danger  to  prop- 
erty or  in  case  of  lightning  and  if  the 
apparatus  will  be  just  as  efficient  in  re- 
ceiving. 

A.  3.  It  is  not  necessary  to  run  a  wire 
down  to  the  ground  if  a  water  or  gas  or 
even  a  radiator  pipe  is  located  near  the 
station.  However,  in  erecting  a  lightning 
ground  it  is  necessary  for  you  to  wire 
from  the  lightning  switch  to  the  outside 
ground,  which  must  connect  from  the 
ninth  floor  as  in  your  case.  The  sensi- 
tiveness of  the  receiving  outfit  will  not 
be  lowered  by  this  ground. 


RECEIVING  RADIUS. 

(776.)  Harry  Cate,  Chattanooga,  Tenn., 
inquires : 

Q.  1.  Can  a  loose-coupler,  a  tuning-coil 
and  a  loading-coil  all  be  used  together 
successfully? 

A.  1.  Yes;  providing  they  are  properly 
connected. 

Q.  2.  What  would  be  the  range  of  the 
following  set  with  an  aerial  45  feet  long 
and  40  feet  high  if  question  (1)  is  cor- 
rect; a  small  tuning  coil  (E.,  I.  Co.'s 
"Electro"  tuning  coil),  a  small  loose  coup- 
ler (E.  I.  Co.'s  "Electro"  loose  coupler)  ; 
loading  coil  with  wave-length  5,000  meters, 
galena  detector,  2  fixt  condensers  and 
3,000  ohm  head  set. 

A.  2.  The  approximate  receiving  range 
of  your  apparatus  is  1,500  miles. 


SERIES  CONDENSER. 

(777.)  John  Huether,  Sharon,  Pa.,  in- 
quires : 

Q.  1.  Is  it  necessary  to  use  a  series  con- 
denser with  a  transmitting  set  on  an 
aerial  75  ft.  long  and  55  ft.  high? 

A.  1.  A  series  condenser  in  the  trans- 
mitting circuit  is  not  necessary  if  the  set 
is  tuned  to  its  natural  period  of  200  meters 
as  permitted  by  the  Government.  With 
the  aerial  you  possess  it  will  not  require 
a  condenser  in  series. 

Q.  2.  Are  you  allowed  to  have  an  input 
of  over  9.1  amperes  on  a  1  K.  W.  trans- 
former to  comply  with  Radio  Regulations, 
or  can  you  have  whatever  input  the  trans- 
former will  draw?  (Operated  from  110 
volts  A.  C.) 


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May,  1917 


THE  ELECTRICAL  EXPERIMENTER 


57 


A.  2.  9.1  amperes  of  current  at  110  volts 
A.C.  is  just  permissible.  However,  we 
would  advise  that  the  transformer  should 
be  operated  on  9  amperes  so  as  to  be  on 
the  safe  side. 


HYDROGEN  GENERATION. 

(778.)  W.  H.  Allum,  Quebec,  Canada, 
asks  ? 

Q.  1.  Would  it  be  practical  to  make  a 
small  apparatus  to  generate  hydrogen  gas 
by  the  decomposition  of  water  by  direct 
current  if  so,  kindly  send  me  a  rough 
sketch  of  apparatus  mentioned. 

A.  1.  The  most  practical  and  inexpen- 
sive method  of  generating  hydrogen  gas 
is  by  the  decomposition  of  water  by  a  di- 
rect current.  In  this  work,  it  is  essential 
not  to  employ  too  great  a  voltage,  but  a 
large  current.  There  has  been  a  large 
number  of  different  types  of  hydrogen 
generators  developed  but  the  one  de- 
scribed on  page  547  in  February,  1916, 
issue  of  this  journal  will  be  found  most 
suitable  for  the  making  of  a  small  ma- 
chine. Not  only  will  you  be  able  to  obtain 
hydrogen  gas  but  at  the  same  time  and 
with  the  same  current  and  water  you  will 
obtain  oxygen  gas. 

Q.  2.  Would  hydrogen  gas  generated  in 
this  manner  burn  by  itself,  the  flame  to 
be  used  for  the  purpose  of  lead  burning 
in  connection  with  the  repair  of  storage 
batteries  and  lead  containers  for  the  same? 
I  have  access  to  125  volt  D.C.  up  to  60 
amperes. 

A.  2.  The  hydrogen  gas  generated  by 
this  electrical  method  will  be  required  to 
be  combined  with  oxygen  making  the  so- 
called  oxy-hydrogen  blow  pipe.  This 
oxygen  will  be  obtained  from  the  same 
generator.  The  gas  produced  will  be  re- 
quired to  be  collected  in  some  reservoir 
chamber  equipt  with  proper  safety  valve?. 

Q.  3.  Has  this  gas  any  injurious  effect 
on  metals ;  if  so  what  metals  are  suitable 
for  the  construction  of  such  apparatus. 

A.  3.  Hydrogen  gas  has  no  injurious 
effects  upon  metals,  but  when  combined 
with  oxygen  and  ignited  they  will  be 
molten  as  it  produces  terrific  heat,  the 
value  of  which  is  next  to  that  of  the  elec- 
tric arc. 

TRANSMITTING  SET. 

(779.)  F.  Gibbons,  Toronto,  Ont.,  asks: 


luenched  gap 


— /  1 

Key      Kick  back 
preventer 


Hotwice  J 
Ammefer 


Correct  Hook-Up  for  Quenched  Spark  Radio 
Transmitting  System. 


Q.  1.  What  instruments  are  required  to 
make  a  transmitting  set  efficient?  How 
do  you  connect  them? 

A.  1.  The  following  instruments  will 
be  required  and  operated  on  110  volts 
alternating  current:  l/,  K.W.  10,000  volt 
transformer,  kick-back  preventer  shunted 
across  the  primary  of  the  transformer, 
heavy  key,  high  tension  condenser  hav- 
ing a  capacity  of  .015  microfarad,  5  sec- 
tion quenched  spark  gap,  oscillation  trans- 
former and  hot  wire  ammeter  used  for 
indicating  the  amount  of  radiation  in  the 
antenna  system.  The  connections  of  the 
instruments  are  given  here.  With  the 
above  mentioned  instruments  and  an  aerial 
composed  of  6  wires  50  feet  long  and  60 
feet  high,  you  should  have  no  trouble  in 
covering  a  distance  of  80  to  100  miles. 


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an  entire  corps  of  electrical  experts  is  yours — to  help  you     »    I??4-  E  7i4S ,   Chica(t(l1'  U-S.A. 
in  your  progress-for  a  whole  year  FREE!  ,  of  gXiSStSSt^SSS 

♦   days'  free  examination.     If  I 
keep  the  books  will  send  $2.00 
within  seven  days  and  $2.00  a 
month  until  $19.80  has  been  paid, 
when  books  and  Consulting  Member- 

See  these  books  for  yourself  before  you  decide  to  buy.  /  ns0htj?y  ^  abned  bo^Tullectl!! 

Remember — don  t  send  us  a  penny.    Just  fill  out  *  your  order, 
the  coupon  and  mail  it.  We'll  send  you  the  entire  t* 
seven  volumes  prepaid.    Use  them  seven  days —  # 

then  if  you  want  to  buy  pay  the  special  reduced  price  at  Name  

the  rate  of  $2.00  a  month.   Send  the  coupon  now.   Your  f 
ambition  says — act — see  for  yourself.  t 

AMERICAN  TECHNICAL  SOCIETY 

Dept.  E.  7445  CHICAGO,  U.S.A. 


Address 

As  I  have  had  1 


>  previous  dealings  with  you.  I  refer  you  to 


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58 


THE  ELECTRICAL  EXPERIMENTER 


May,  1917 


NATIONAL 
CALLING 
SYSTEM 


Finds  Executives 
Instantly! 

On  the  Dock     On  Shipboard 

ON  long,  dimly  lighted  docks,  piled 
high  with  merchandise,  it  is  not 
easy  to  get  into  immediate  com- 
munication with  Superintendents  or 
Foremen.  On  shipboard,  too,  Officers  on 
tours  of  inspection  or  off  duty  may  be 
wanted  urgently  —  and  no  one  knows 
where  they  are. 

But  the  National  Calling  System  will 
find  such  men  at  once.  To  illustrate: 
The  telephone  operator,  having  been  in- 
structed to  find  Mr.  Smith,  sets  the 
small  levers  on  the  calling  instrument 
for  his  code  number  and  then  gives  the 
operating  key  a  quick  turn.  Instantly, 
this  code  number  is  sounded  simultane- 
ously all  over  the  dock  or  vessel,  as  the 
case  may  be,  on  electric  chimes,  horns, 
buzzers,  or  whatever  signaling  devices 
are  in  use. 

Mr.  Smith  cannot  get  out  of  hearing  of 
one  of  these  signals,  no  matter  where  he 
goes.  He  gets  his  call  instantly  and 
immediately  answers  from  the  nearest 
telephone  or  reports  in  person. 
No  Executive  or  Officer  on  ship  or  dock 
can  afford  to  be  out  of  reach.  The 
National  Calling  System  enables  him  to 
go  where  he  will  because  he  can  be  found 
instantly,  at  any  time. 

Send  for  Complete  Information 
and  Descriptive  Booklet  No.  34. 

NATIONAL  SCALE  COMPANY 

(ELECTRICAL  DIVISION) 
5  RAPIDS  STREET,  CHICOPEE  FALLS,  MASS, 

Also  Manufacturers  of  [National  Counting  Machines 
and  National-Chapman  Elevating  Trucks 


RADIO  WIRING  DIAGRAM. 

(780.)  Experimenter  Reader,  Pleasant 
Plains,  111.,  desires : 

Q.  1.  Please  give  me  a  diagram  of  the 
following  instruments  for  both  damped 
and  undamped  wave  reception :  Loose 
coupler,  loading  coil,  Audiotron  bulb,  ga- 
lena detector,  buzzer  and  push  button,  two 
variable  condensers,  'phones  and  a  large 
loose  coupler  for  undamped  waves. 
Please  give  necessary  switches  for  chang- 
ing from  damped  to  undamped  for  either 
detector,  and  for  using  the  variables  on 
either  the  damped  or  undamped  set.  Also 
the  necessary  loading  inductances  in  the 
undamped  circuit  if  there  has  to  be  any. 

A.  1.  We  give  herewith  a  complete 
wiring  diagram  of  a  damped  and  un- 
damped receiver,  showing  the  necessary 
switches. 

Q.  2.  Could  this  set  receive  music  on 
the  undamped  wave?  If  not,  please  tell 
me  how? 

A.  2.  Yes,  providing  the  Audiotron  tube 
is  set  oscillating. 

Q.  3.  The  probabilities  of  Congress  put- 
ting a  stop  to,  or  shutting  down  the  Ama- 
teur stations  of  the  United  States? 

A.  3.  The  1912  radio  law  provides  that 
the  President  has  authority  to  close  all 
radio  stations  in  case  of  war. 


si  <? 


DPDT  sry 

Audiotron 


r,.—  Buzzer 


Hook-up  for  Audion  and  Crystal  Detectors 
to  Be  Used  in  Receiving  Damped  and  Un- 
damped   Radio  Signals. 


AUTOMOBILE  SPARK  COIL. 

(781.)  Leo  Peterson,  Thorsby,  Ala., 
wants  : 

Q.  1.  Would  an  automobile  coil  with 
three  binding  posts  giving  a  spark  inch 
long  work  all  right  for  wireless? 

A.  1.  It  will  work  satisfactorily  for 
transmitting  a  short  distance. 

AEROPLANE  RADIO  GROUND. 

(782.)  George  Sloan,  St.  Louis,  Mo., 
writes  : 

Q.  1.  I  would  like  to  know  the  address 
of  Dr.  Nikola  Tesla. 

A.  1.  The  address  of  Dr.  Nikola  Tesla 
is  8  West  40th  St.,  New  York. 

Q.  2.  How  do  aeroplanes  get  a  ground 
for  their  wires. 

A.  2.  By  suspending  a  wire  from  the 
aeroplane  which  trails  behind  the  machine. 

RADIO  ARC  TRANSMITTER. 

(783.)    Mr.   ,  Pittsburgh,  Pa.,  asks 

several  questions  regarding  an  article  on 
an  Arc  Type  Radio  Transmitter  by  Mr. 
Gordon  C.  Farmer,  which  appeared  in  the 
February  issue : 

A.  1.  It  is  possible  to  obtain  a  fairly 
high  note  with  such  an  arc  transmitter, 
especially  if  the  arc  is  shunted  with  a  suit- 
able tone  circuit  after  the  method  of  Von 
Lepel.  You  might  use  a  43  plate  Murdock 
variable  condenser  or  the  equivalent,  pro- 
viding the  plates  are  immersed  in  oil. 
The  size  of  the  plates  in  the  arc  would 
remain  the  same  for  mica  instead  of 
paper;  paper  has  been  found  best  for  this 


HIGH  FREQUENCY  OUTFITS 


We  specialize  in  all  forms  of  high  frequency  appa- 
ratus, including  apparatus  for  generation  of  Violet 
rays  for  medical  treatment  and  sterilization  of 
water.  X-Rays.  etc  The  outfit  illustrated  is 
only  one  of  three  sizes  we  build  ranging  in 
price  as  follows:  $25.00;  $35.00;  $50.00.  We  also 
supply  all  forms  of  high  frequency  electrodes. 

ROSENTHAL  LABORATORIES,  Camden,  N.  J. 


SEAMLESS  CARDBOARD  TUBING 


♦  IN  SIZES  SUITABLE  FOR  ♦ 
^Tuning  Coils,  Loose  Couplers,  Tesla  Coils,  Etc. 
4PRICE  LIST— Smooth  Wound  Wireless  Tubes* 

♦  Outside  Lgth.  Price  Par,\        GENERAL  INFORMATION  ♦ 

Post 


GENERAL  INFORMATION 

These  prices  include  PARCEL 
POST  CHARGES:  and  are 
shipped  at  once  on  receipt  of 
order  and  remittance. 
We  CANNOT  furnish  these 
tubes  in  longer  lengths  than 
7H*  unless  ordered  in  quan- 
tities of  100  of  a  size. 

We  CAN    furnish  SPIRAL 
WOUND     TUBES     in  any 
length  up  to  45  inches  at  .02  per 
inch   in    the   following  Inside 
.  diameters.  313-4-4). i -5-6. 
SPECIAL  GRAY  TUBES 
x6%"    $lea.  18"x7^"x7Jf 


I8"x6M"x6^"     $lea.    18"x7^"x7%"    $1  ea.  & 

|  BEETLE  &  MACLEAN  MFG.  CO.  f 

A  21  BROMFIELD  ST.  BOSTON,  MASS.  X 

^^^^^^^^^^^^^^^ 


F 


ORMICA 

An  Insulating  Material  of  Excep- 
tionally High  Dielectric  and  Me- 
chanical Strength,  Waterproof, 
Heat  Resisting  and  Permanent. 


Supplied  in  Jet  Black  or  Brown  Sheets. 
Also  Furnished  in  the  form  of  Finished 
Panels  accurately  cut  to  specifications. 


THE  FORMICA  INSULATION  CO. 


CINCINNATI,  OHIO 


Electro-Set  Arf»n6ton  Tested 
WIRELESS  MINERALS 


i  your 

25 


When  you  place  an  Electro-set 
Arlington  Tested  Crystal  in  your 
detector  you  KNOW  that  it  " 
is  sensitive.  Every  crystal 
is  carefully  SELECTED  «,  « 
and  TESTED  before  beine  „ 
individually  PACKED  and tent8 
SEALED  under  our  label.  Electro- 
set  N.  A.  A.  minerals  have  proven 
their  superior  worth  in  actual 
service  throughout  the  world. 
Sold  by  leading  dealers  or  by  mail 
direi-t.  Silicon  or  Galena  25  cts  each. 

THE  ELECTRO-SET  CO. 
Dept.  E-12  Cleveland,  Ohio 


STROMBERC  .  CARLSON  <C0.25 
RADIO    HEAD  SET   


Stromberg  -  Carlson   Telephone  Mfg. 
Rochester,   N.  Y. 


Co. 


You  benefit  by  mentioning  "The  Electrical  Experimenter"  when  writing  to  advertisers. 


May,  1917 


THE  ELECTRICAL  EXPERIMENTER 


59 


purpose  after  exhaustive  experimentation. 
The  paper  is  pierced  with  a  pin-hole  at 
the  center  when  assembling  the  arc  gap, 
and  also  it  is  extremely  important  as  to 
just  what  kind  of  paper  is  employed — one 
of  the  best  papers  for  the  purpose  hav- 
ing been  found  to  be  a  certain  kind  of 
water  line  bond.  The  editor  of  this  col- 
umn does  not  recollect  just  now  as  to 
who  made  this  paper,  but  you  can  obtain 
the  name  of  the  concern  supplying  this 
particular  writing  paper  by  communicating 
with  the  Institute  of  Radio  Engineers,  New 
York  City. 

An  arc  may  be  started  with  500  volts 
using  a  small  gap  of  1/100  inch  or  so, 
especially  where  the  circuit  is  made  and 
broken  by  a  quick  break  switch.  The 
transformer  described  by  Mr.  Farmer 
would  be  rated  at  about  one-half  kilo- 
watt. 


FORMULA  AND  RECIPE  BOOK. 

(784.)  Tom  Otis,  Cedar  Rapids,  Iowa, 
writes  for  information  on  a  book  contain- 
ing formulas  and  recipes : 

A.  1.  You  will  find  books  containing  sev- 
eral hundred  different  formulas  listed  in 
our  Book  Catalog,  which  we  shall  be 
pleased  to  forward  you  on  request.  We 
shall  also  continue  to  publish  a  number  of 
these  formulas  monthly  in  The  Electri- 
cal Experimenter. 


ELECTRICITY  AND  LIFE. 

(Continued  from  page  24) 

like  discharge  three  feet  in  diameter  (Fig. 
1),  and  gives  a  heavy  arc  over  two  feet  in 


How  Small  Size  Tesla  Coil  for  Medical  Treat- 
ment Is  Built;  "b"  Is  the  Primary,  "a"  the 
Secondary. 


length.  (Fig.  2.)  This  shows  remarkable 
efficiency  when  it  is  considered  that  the  re- 
sonator is  excited  by  a  "Type  E"  trans- 
former drawing  only  1  K.W.  and  a  con- 


Unique     Stationary     Spark     Gap  Having 
Grooved  Faces,  as  Devised  by  Dr.  Strong. 

denser  of  but  .01  m.f.  capacity.  A  small 
rotary  spark  gap  is  used  such  as  is  sup- 
plied by  the  E.  I.  Co.  This  result  is  made 
possible  by  the  use  of  the  separate  induc- 
tance in  series  with  the  resonator  primary 
(exactly  the  same  as  that  described  in  con- 
nection with  the  therapeutic  apparatus) 
(d  Fig.  8).  The  writer  believes  his  re- 
sonator gives  the  most  spectacular  dis- 
charge ever  obtained  from  1  kilowatt  of 
energy. 

Ordinary  plate  condensers  are  used,  made 
from  8  x  10  inch  negative  glass,  coated  on 
both  sides  with  tin-foil  6x8  inches  (a  Fig. 
7).    Six  pairs  of  plates  assembled  into  a 


QST 


AMATEURS! 


Knob  Only 


No.  20  No.  21 

Build  your  own  receiving  sets  and  save  money.  Handsome  knobs  1  inch  high  and  ]  1-4  inch  and  2M 
inches  in  diameter.  Brass  Collar  5-16  inch  high.  Self  cleaning  switch  lever  1-18  inch  and  1-14  inch  long. 
These  switches  will  make  any  set  look  100  per  cent  better. 

Club  together  and  buy  them  in  100  lots  at  the  following  orices: 
No.  20  Switch  complete    -    -    per  100    $52.00  No.  15  Brass  contacts  1-4  in. 

"    21      "  -    -        "  36.00  x  1-4  tapped  6-32     -    per  100  $1.75 

44     1  Knob  only    -    -    -    -        44  30.00  44    1  4  Brass  contacts  5-16  in. 

44     2     4  4       44    -   -   -   -   -        44  1  5.00  x  5-16  tapped  6-32    -       44  2.50 

ROTARY  GAP  DISCS 


5  3-4  inch 
diameter 

1-8  inch 
I  thick 


Carrying 
capacity 
2  K.  W. 


Made  of  highly  polished  Formica  and  turned  absolutely  true.  Guaranteed  not  to  warp  or  crack.  "A" 
™c  represents  our  famous  chord  note  rotary.  Type  "A"  disc  furnished  with  either  8  or  12  points — type 
"B"  disc  in  6-8  or  12  points  at  no  additional  charge.    Chuck  drilled  1-4  inch  shaft. 

Disc  complete  with  chuck      -    -    -    -    $3.50  Chuck  only  -   --   --    --    --   -  .60 

"         less       44      _____     3.00  Ex  for  spec,  drilled  chuck  up  to  3-8  in.  .30 

KLITZEN  WIRELESS  APPARATUS  COMPANY,  1133  Herrick  Ave.,  Racine,  Wis. 


'NEW 


'NEW 


TWO  COIL 
Amplifying  Transformer 

Especially  adapted  and  recommended  for  use  with  all  tubular 
vacuum  detectors. 
Result  of  six  months  work  and  great  expense. 

10  TO  25  TIMES  AMPLIFICATION 
Introductory  Offer  $9.90 

Delivery  free  anywhere  in  U.  S.  if  cash  accompanies  order. 

ONE  STEP  AMPLIFIER  PANEL 

Made  of  hard  rubber  with  two  30  cell  batteries  without  tubes. 
Price  $30.00  Ready  For  Delivery 

Our  new  composition  rheostat  absolutely  essential  for  efficient 
filament  control  for  all  vacuum  detectors.  Write  for  description. 

Satisfaction  Guaranteed 
AUDIO  TR0N  SALES  CO.,  315  Lick  Bldg.,  San  Francisco,  Cal. 


This  Efficient  Tuner  Only  $8.00 

"Your  Tuners  are  very  selective  and  efficient  and  highly  praised  by 
the  members  of  the  Auburn  Y.M.C.A.  Radio  Club.— Robert  Eccles, 
Secretary  and  Treasurer." 

Big  Undamped  Tuner,  20  taps  on  primary,  14  on  secondary  and  brings 
in  German  stations  fine,  only  SI. 5. 00. 

15,000  Meter  Loading  Inductance  in  quartered  oak  case  with  9  taps, 
only  $8.00.    Send  2-cent  stamp  for  bulletins. 

COLBY'S  TELEGRAPH  SCHOOL  Auburn,  N.  Y. 


You  benefit  by  mentioning  "The  Electrical  Experimenter"  when  writing  to  advertisers. 


6o 


THE  ELECTRICAL  EXPERIMENTER 


if  u  a  dd  uynamo 

tl  WAT Eg  m  ri  t 

nan AV1  u  1 

For  Bo.ys  $ 

For  producing  current  for  in- 
ductance coils,  re-charging 
storage  batteries,  elec- 
troplating and  hun- 
dreds of  other  uses. 
Well  constructed 
throughout,  exception- 
ally smooth  running 
and  highly  efficient.  A 
good,  strong,  durable 
dynamo. 

AT  ALL  LIVE  DEALERS 

Insist  on  your  dealer  showing  you  the  KNAPPline— 
KNAPP  goods  are  best.  If  your  dealer  cannot  supply 
you.  order  direct.  Send  for  FREE  illustrated  cata- 
logue showing  a  complete  line  of  Electrical  Motors 
and  Novelties  ranging  in  price  from  10c  up. 

KNAPP  ELECTRIC  &  NOVELTY  CO. 

523  West  51st  Street,  N.  Y.  City 


ENCLOSED 
ROTARY  GAP 

This  gap  has  been  designed 
to  sell  at  a  low  price  and  to 
meet  the  demands  of  ama- 
teurs for  a  good,  enclosed 
and  silent  gap.  Finished  in 
dull  black.it  will  add  tothe 
appearance  of  your  set. 
It  is  made  in  one  styleonly, 
for  all  powers  up  to  I-KW, 
and  can  be  mounted  in  al- 
most any  position. 
The  gap  is  enclosed  in  a 
circular  iron  housing  8  inches 
in  diameter  and  2}^  inches 
thick,  with  removable  cover 
(for  inspection).  The  adjust- 
ment can  be  as  close  as  desired 
between  sparking  points. 
Rotating  disc  is  of  brass  with  12  projecting 
round  brass  arms  (total  diameter  6  inches), 
mounted  on  shaft  running  in  bronze  bearing 
and  is  belt  driven  by  small  motor  giving  a 
variety  of  tones  depending  upon  the  speed. 

When  in  operation  this  gap  is  very  quiet 
Price  complete,  without  motor,  $8.50 
J.  Herbert  Ferris,  211  Catalpa  Drive,  Royal  Oak,  Mich. 


ONE-INCH 


JUMP  SPARK 
COILS  for 
WIRE- 
LESS 

$3.25 

Guaranteed  to  jump  as  specified 
or  money  refunded. 

WISCONSIN  IGNITION  CO. 

609-513  Cedar  Street,  Milwaukee,  Wisconsin 


Send  two  cent  stamp  'or  circulars 

CLIFF  MFG.  CO.,  Brookfield,  Mass. 


unit  and  boiled  in  wax  give  a  capacity  of 
.01  m.f.  For  safety  it  is  better  to  employ 
four  of  these  sections  connected  in  pairs 
of  .02  m.f.  each  (b  Fig.  7).  To  run  this 
resonator  at  full  power  for  long  periods  of 
time  it  would  be  safer  to  use  a  series 
multiple  condenser  consisting  of  three  sec-. 


Connection    Scheme   for  Tesla   Coil  "f — g," 
Shorting  Switch  "e."  Tuning  Inductance  "d," 
Spark  Gap  "c,"  Condenser  "b"  and  Step-up 
Exciting  Transformer  "a." 

tions  of  .03  m.f.  each  in  series.  Such  a 
condenser  would  contain  108 — 8  x  10  inch 
plates,  and  would  be  expensive,  bulky  and 
very  heavy.  For  this  reason  the  writer  has 
found  it  much  more  convenient  to  use  a 
single  12  plat  (.01  m.f.)  condenser  across 
the  transformer  secondary  and  to  replace 
it  when  it  punctures.  The  large  resonator 
was  operated  for  six  months  in  lecture  and 
experimental  work  before  a  condenser  sec- 
tion broke  down. 

The  cone  for  the  secondary  of  the  large 
resonator  is  of  hea  paperboard  and  was 
built  for  the  author  by  Bicknell  and  Fuller 
of  Boston.  Its  dimensions  (see  Fig.  6) 
were  suggested  by  Mr.  Earle  L.  Ovington, 
the  cone  being  similar  in  shape  to  those 
used  by  Mr.  Ovington  in  the  New  York 
Electrical  show  several  years  ago.  Any 
amateur  can  make  a  cone  of  this  kind  by 
superimposing  strips  of  heavy  paper,  soaked 
in  paste,  over  a  wooden  framework.  The 
secondary  winding  consists  of  400  turns  of 
No.  27  D.C.C.  copper  magnet  wire.  Two 
parallel  strands  of  wire  are  wound  onto 
the  cone,  the  adjacent  turns  in  contact; 
after  winding,  one  strand  of  wire  is  re- 
moved, leaving  a  space  equal  to  the  diam- 
eter of  the  wire  between  each  of  the  400 
turns.  The  cone  and  winding  is  then  treated 
with  several  coats  of  "Armalac"  (ordinary 
shellac  will  not  answer). 

The  primary  consists  of  five  turns  of  thin 
copper  ribbon  1  inch  wide,  l/%  inch  paper- 
board  strips  being  placed  between  the 
turns.  The  diameter  of  the  coil  is  24". 
When  completed  it  is  taped  and  rotated 
in  a  pan  of  melted  wax  until  thoroly  im- 
pregnated. The  terminal  shown  in  the  pho- 
tographs is  made  from  a  large  brass  oil- 
can, the  stem  being  removed  and  replaced 
by  a  3"  brass  "bed-ball."  The  terminal  is 
not  attached  to  the  cone  but  simply  rests 
on  its  upper  surface  in  contact  with  the  end 
of  the  secondary  wire.  The  primary  and 
secondary    are    separately    supported  by 


Class  plate  s'-io' 
a        I  b 


Tinfoil  6''0' 


Condenser  Details 
7 


Details    for    Building    High    Tension  Glass 
Plate  Condenser  to  Be  Connected   in  Tesla 
Coil  Circuit. 

quare  wooden  blocks ;  the  coupling  is  rather 
loose,  the  bottom  of  the  resonator  being  at 
least  two  inches  above  the  primary.  The 
lower  end  of  the  secondary  coil  is  attached 
to  the  inner  primary  terminal  and  grounded. 


May,  1917 

Oh,  You  Skinny! 

Why  stay  thin  as  a  rail?  You  don't  have  to  I 
And  you  don't  have  to  go  through  life  with  a 
chest  that  the  tailor  gives  you  ;  with  arms  of 
childish  strength:  with  legs  you  can  hardly 
stand  on.  And  wnat  about  that  stomach  that 
flinches  every  time  you  try  a  square  meal? 
Are  you  a  pill-feeder? 

Do  you  expect  Health  and  Strength  in 
Tabloid  form — through  pills,  potions 
and  other  exploited  piffle  ? 
You  can't  do  it;  it  can't  be  done. 

The  only  way  to  be  well  is  to  build  up  your 
body — all  of  it— -through  nature's  methods — 
not  by  pampering  the  stomach.  It  is  not  FATE 
that  is  making  you  a  failure;  it's  that  poor, 
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Standard  and  Special  Shapes,  Regardless 
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A  pair  of  rolls  iy2"  long  and  1)4"  in 
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May,  1917 


THE  ELECTRICAL  EXPERIMENTER 


61 


Perfect  resonance  is  obtained  by  varying 
the  number  of  turns  in  the  inductance  coil 
in  series  with  the  primary.  (Fig.  8.)  This 
tuning  system  enables  us  to  perform  many 
brilliant  experiments  otherwise  impossible, 
such  as  illuminating  wires  stretched  across 
a  lecture  hall,  lighting  an  inverted  um- 
brella, etc.  Some  new  and  very  spectacular 
experiments  with  this  large  resonator  will 
be  described  and  illustrated  in  an  article 
in  next  month's  "Electrical  Experi- 
menter," entitled  "Methods  of  employing 
high-frequency  currents  in  medical  and  lec- 
ture work." 

The  author  is  greatly  indebted  to  Mr. 
O.  K.  Luscolm,  for  advice  and  assistance 
which  made  possible  the  successful  con- 
struction of  the  large  resonator. 


b 


®  F>9  8  Toqround 

Method   of  Connecting   Transformer,    H.  T. 
Condenser,    Rotary   Spark   Gap  and  Tuning 
Inductance  "d"  to  Large  Oudin  Coil. 

At  a  recent  lecture  before  the  Belfast 
Association  of  Engineers  Mr.  A.  W. 
Brown  suggested  the  transmission  of 
power  generated  from  the  tidal  rise  and 
fall  of  the  water  at  Strangford  Lough  and 
Lough  Neagh  to  Belfast.  Thus,  at  Strang- 
ford Lough  there  are  twenty  square  miles 
of  water  available,  the  spring  tides  have  a 
rise  of  14J/2  feet  and  the  neap  tides  a  rise 
of  ll]/2_  feet,  with  a  range  of  7j/2  feet. 
About  20,000  horsepower  could  be  devel- 
oped for  a  period  of  two  and  one-half 

THE   WASHINGTON'S  BIRTHDAY 
RELAY  PRIZE  WINNERS. 

{Continued  from  page  23) 
live  in  a  state  that  has  as  much  real  earth 
in  it  as  is  blown  into  the  air  in  some  of 
our  larger  states  during  every  wind  storm ! 

These  few  think  they  are  very  impor- 
tant and  if  you  don't  do  as  they  say,  why 
the  Government  will  close  you  up.  They 
say  "The  Danger  Signal  is  up."  Did  you 
ever  hear  of  a  good,  red-blooded  Ameri- 
can Kid  who  could  be  bluffed?  No!  It 
is  not  in  your  make-up.  The  Government 
is  only  too  anxious  for  you  to  perfect 
yourself  in  the  art,  and  help  it  out  by 
joining  the  "Radio  Reserves." 

PRIZES. 

This  is  a  stunner  for  one  who  would 
like  to  give  everybody  that  helped  a  prize, 
but  it  can't  be  done,  so  I  am  going  to  ask 
the  boys  who  acted  as  sending  stations  to 
consider  that  they  are  one  of  the  family 
and  help  me  by  agreeing  that  the  prizes 
should  go  to  the  boys  who  made  the  best 
records  in  receiving  and  delivery.  The 
rest  of  the  amateurs  will  be  rewarded  by 
having  their  names  printed  in  this  maga- 
zine, so  that  when  you  grow  older  and 
have  a  little  one  on  each  knee  in  front 
of  the  old  log  fire,  some  cold  night,  you 
may  read  to  them  about  Daddy  and  what 
he  did  when  he  was  a  mere  boy. 

Before  you  all  get  busy  reading  about 
the  prize  winners,  I  want  to  call  your  at- 
tention to  several  hard  workers  who 
turned  in  the  most  complete  reports,  or 
"logs,"  of  the  relay,  that  the  writer  has 
ever  had  the  privilege  of  reading. 

Hoyt,  of  Hayward,  California,  6  SI, 
who  is  also  a  prize  winner,  turned  in  the 
most  complete  report  ever  seen. 

Stewart  of  St.  Davids,  Pennsylvania,  3 
ZS,  whom  you  all  know  as  one  of  the  hard 
hours,  the  power  available  varying  from 
maximum  to  minimum  every  six  hours. 


workers  of  the  Radio  Association  of  Penn- 
sylvania, turned  in  a  truly  wonderful  re- 
port, but  he  stayed  up  till  nearly  6  a.m. 
the  next  morning,  boys,  and  from  the 
looks  of  his  "log,"  he  went  to  sleep  with 
the  pen  in  his  hand.    It  really  only  took 


me  about  two  hours  to  digest  this  report. 

Emerson  of  Dallas,  Texas,  5  DU,  as 
ex-man-o-warsman,  turned  in  a  regular 
Navy  Report,  brim  full  of  interest  and 
curt  reports.  He,  too,  along  about  the 
dog  watch,  evidently  slept  on  duty.  Bet 


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PARTIAL  CONTENTS 

Magnetism —  Induction  —  Experiments  —  Dynamoa  ■ — 
Electric  Machinery —  Motor  a  —  Armatures  —  Armature 
Windings  Installing  of  Dynamos  Electrical  Instru- 
ment Testing  Practical  Management  of  Dynamos  and 

Motors  Distribution  Systems  Wiring  Wiring  Dia- 
grams Sign  Flashers  Storage  Batteries  Principirs 

of  Alternating  Currents an'l  Alternators  Alternating 

Current  Motors  Transformers — Converters  Recti- 
fiers Alternating  Current  Systems  Circuit  Breakera 

— Measuring    Instruments  Switchboards — Wiring — 

Power  Stations — Installing  Telephone — Telegraph — 

Wireless  Bells  Lighting  Railways.     Also  many 

Modern  Practical  Applications  of  Electricity  and 
Ready  Reference  Index  of  the  10  numbers. 


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Signature  . 

Occupation  

Business  Address.  , . . 


Residence . 
Reference  ...... 


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02 


THE  ELECTRICAL  EXPERIMENTER 


May,  1917 


he  is  glad  he  wasn't  aboard  the  good  ship 
"Hardship,"  as  they  shoot  men  in  war- 
time for  sleeping  on  duty.  He  was  right 
on  deck  tho,  all  the  time,  and  the  writer 
could  clearly  read  his  calls  to  9  ZF  and 
answers  to  the  boys  east. 

The  boys  of  the  San  Francisco  Radio 
Club  also  made  splendid  reports,  as  did 
also  our  College  Professors,  who  are  al- 
ways with  us. 

A  perfectly  legal  report  was  also  re- 
ceived from  a  staid  old  lawyer  in  Jack- 
sonville, Fla.,  who  prefaced  his  letter  with 
the  remark  that  he  was  not  trying  for  a 
prize,  but  being  a  "Radio-Bug,"  he  just 
could  not  keep  still. 

A  well  known  D.  D.  S.  in  Elmira,  also 
sent  in  a  very  complete  report  and  called 
it  a  great  night's  work. 

I  just  compared  two  interesting  letters 
from  one  amateur. 

iqi6.  He  was  diligently  stabbing  a  piece 
of  galena  and  complaining  about  his  vi- 
brator sticking  011  his  one  inch  coil.  Said 
he  did  not  get  M.S.G.  but  thought  he  would 
report  anyway. 

1917.    He  sent  me  a  list  of  stations  he 


hears,  as  long  as  your  arm,  and  he  is  now 
sporting  a  one  K.W.  and  working  as  a  star 
relay  station,  1,000  miles  being  as  nothing 
to  him.  I  heard  him  from  my  station — 
clear,  quick  sending;  prompt  business- 
like signatures,  and  abbreviations  that 
went  clear  over  my  head.  "The  world 
do  move!" 

PRIZE  WINNERS. 
Mr.  E.  B.  Duvall  and  Mr.  A.  P.  Smith 
are  awarded  the  prize  of  the  Electro  Im- 
porting Company — their  ''Nauen  POZ"  Ra- 
dio Receiving  Set!  These  young  men 
operate  jointly  the  Radio  Station,  3  AK, 
in  Baltimore,  Md.  This  prize  is  awarded 
for  the  quickest  delivery  of  both  mes- 
sages, and  particularly  in  being  on  the  job 
for  the  return  M.S.G.  No  one  but  the 
sending  stations  east  of  9  ZF  knew  when 
the  east  bound  M.S.G.  was  coming  thru. 
If  this  had  been  a  real  emergency  call  for 
Government  help  on  200  meters,  these 
same  fellows  would  have  landed  the  mes- 
sage just  the  same.  Congratulations  to 
them. 

SECOND  PRIZE. 
Mr.   W.    B.    Pope,   4   AA,   of  Athens, 


Georgia,  is  awarded  the  Professional  Wave 
Meter,  donated  by  the  Electro  Importing 
Company  of  New  York.  It  was  awarded 
for  long  distance  reception,  prompt  busi- 
ness-like delivery,  and  for  perfect  index- 
ing, timing  and  marking  both  east  and 
westbound  messages,  received  in  approved 
commercial  style.  From  a  study  of  the 
Q.R.M.  map,  he  was  seriously  handicapped 
on  both  messages,  and  is  heartily  con- 
gratulated by  the  writer  and  all  good  ra- 
dio "sports." 

THIRD  PRIZE. 
Kenneth  Briggs  of  Rochester,  N.Y.,  8 
MG,  whom  you  all  remember  as  almost 
catching  up  with  C.  E.  Hughes,  the  presi- 
dential candidate,  with  a  copy  of  the  Re- 
lay Message  on  October  27th,  1916,  is 
awarded  the  One  K.W.  Thordarson  Trans- 
former, donated  again  by  the  Thordar- 
son Transformer  Company  of  Chicago, 
thru  their  Mr.  Connors.  Mr.  Briggs  is 
congratulated  on  his  persistency,  good  re- 
ceiving, prompt  delivery  and  true  Ameri- 
can spirit,  as  he  showed  not  the  least 
jealousy  toward  several  who  were  working 
against  him.  The  Q.R.M.  map  showed 
marked  interference,  particularly  on  west- 
bound messages,  and  he  can  thank  the 
Q.R.T.  of  W.  C.  Ballard,  Jr.,  at  Cornell 
College,  8  XU,  for  giving  him  the  chance 
to  win  this  prize.  I  hope  he  will  perfect 
his  sending  apparatus,  and  line  up  with  the 
Q.R.M.  League. 

FOURTH  PRIZE. 

Scott  High  School  of  Toledo,  Ohio,  is 
awarded  the  William  B.  Duck's  celebrated 
Arlington  Tuner;  for  long  distance  recep- 
tion with  moderate  apparatus ;  diligent  and 
persistent  listening  for  the  return  message 
and  very  complete  business-like  report. 
FIFTH  PRIZE. 

Leander  L.  Hoyt  of  Hayward,  Cal.,  6  SI, 
is  awarded  the  Chambers  No.  749  tuner  for 
the_  reception  of  arc  and  spark  signals. 
This  prize  is  awarded  for  the  long  distance 
work  and  incessant  effort  to  line  the  boys- 
up  in  that  neighborhood  to  a  realization 
that,  for  once,  California  would  be  put  on 
the  Relay  Map.  Mr.  Hoyt,  besides,  turned 
in  one  of  the  most  wonderful  and  complete 
reports  on  everything  of  importance  that 
happened,  from  the  moment  the  westbound 
M.S.G.  left  New  York,  until  the  eastbound 
message  arrived  in  the  same  city.  The  ab- 
sence of  jealousv  shows  he  is  a  real  man — 
an  American — and  one  from  whom  we  will 
hear  more  later  on.  To  satisfy  you  all,  we 
will  publish  this  report  in  this  magazine,  if 
Mr.  Hoyt's  permission  to  do  so  may  be  ob- 
tained later.  We  most  earnestly  hope  Mr. 
Hoyt  will  not  find  as  much  real  cause  for 
worry  when  listening  in  on  the  wave 
lengths  from  6,000  meters  up  as  he  heard 
during  the  relay  from  600  meters  down. 
California  is  surely  lined  up  now  for  good 
work  with  such  'ellows  as  6  EA  for  send- 
ing L.D.  and  6  SI  for  detail  work.  Mr. 
Hoyt  will  make  a  valuable  addition  to  the 
Q.R.M.  League. 

SIXTH  PRIZE. 

Mr.  and  Mrs.  C.  Candler— 8  NH,  whom 
you  all  know  and  have  heard,  are  located 
in  St.  Mary's,  Ohio,  but  their  "Sigs."  do 
not  stay  at  home.  During  the  Presidential 
Relay,  this  station  received  six  hard-earned 
credits  and  later  stated  that  their  trans- 
former was  not  working  right.  They  sure- 
ly proved  this  during  the  last  relay,  as 
their  "Sigs."  were  everywhere,  and  if  it  had 
not  been  for  this  station,  lots  of  stations 
south  and  west  would  never  have  received 
the  Westbound  M.S.G.  at  all.  Some  who 
did  not  know  8  NH  was  supposed  to  help 
on  relay,  reported  him  as  Q.R.M.  When 
you  all  get  your  stations  arranged  so  that 
you  can  Q.R.M.  boys  1,000  miles  away,  you 
are  sure  on  the  trail  of  efficient  long  dis- 
tance work. 

This  station  is  awarded  the  prize  of  the 


"Geyser"  Electric  Water  Heater 


The  Hot  Bath  is  Ready 

Continuous  Flow  of  Water  as  Desired.    Always  Ready. 

You  only  pay  for  electricity  as  used.  All  water  that  passes  through  the  "Geyser"  is 
thoroughly  sterilized.  The  "  Geyser"  is  perfectly  insulated  and  is  absolutely  safe,  no 
danger  of  short  circuiting  or  electric  shock. 

Cold  to  Hot  Water  by  Merely  Turning  Handle. 

Both  the  water  and  the  current  act  together  and  both  controlled  by  the  movement  of 
the  faucet  handle.  To  secure  hot  water  turn  handle  to  the  left,  for  cold  water  turn  to 
the  right,  at  the  center  both  the  water  and  current  are  shut  off. 

The  Supreme  Court  has  decided  that  we  control  the  absolute  right  to  the  manufacturing  of 
"Geyser"  Electric  Water  Heater.    Others  take  warning,  as  we  will  prosecute  any  infringing 
on  same.  W rite  us  today  to  send  you  full  information 

FELDMAN  MFG.  CO.,  Inc.  1514  Times  Building,  New  York 


You  benefit  by  mentioning  "The  Electrical  Experimenter"  when  writing  to  advertisers. 


May,  1917 


THE  ELECTRICAL  EXPERIMENTER 


63 


Perfection  Radio  Laboratory  of  Clinton, 
Iowa.  One  Short  Wave  Amplifying  Tun- 
er. The  writer  used  a  tuner  of  this  make 
during  the  last  relay  and  could  hear  the 
"Sigs."  of  4  CL  and  2  PM,  very  Q.S.A.  It 
is  a  very  small  and  compact  affair  and  am 
sure  8  NH  will  find  it  a  most  valuable  ad- 
dition to  their  station.  The  owner  or  mak- 
er of  this  apparatus  calls  it  a  "Cow  Suck- 
er." It  is  the  most  sensitive  and  reliable 
receiver  the  writer  has  ever  used. 

SEVENTH  PRIZE. 
O.  R.  Terry,  Stoughton,  Wis.,  is  awarded 
the  prize  of  the  Manhattan  Electric  Sup- 
ply Company  of  Chicago.  This  is  a  pair 
of  3,000  Ohm  Mesco  phones.  They  are 
dandies,  and  the  writer  has  been  using  a 
pair  for  the  last  year.  Mr.  Terry  made  a 
creditable  report  and  great  record  for  re- 
ceiving thru  Q.R.M.  of  the  worst  kind. 

EIGHTH  PRIZE. 
The  Phoenix  Radio  Club  of  Phoenix, 
Ariz.,  is  awarded  the  donation  of  Mr. 
Philip  E.  Edelman  of  St.  Paul,  Minn.  This 
is  his  latest  book,  "Experimental  Wireless 
Stations,"  and  it  is  a  wonder  how  so 
much  useful  information  has  been  crowded 
into  such  a  compact  space.  This  book 
will  put  Arizona  on  the  wireless  map  for- 
ever, and  the  prize  is  awarded  for  long 
distance  reception,  cooperation  in  the  re- 
lay, and  real  genuine  American  patriot- 
ism in  keeping  quiet  when  necessary. 

INSTRUCTIONS. 
The  prize  winners  may  obtain  these 
prizes  by  writing  to  the  above  Donees  and 
giving  your  name  and  address,  and  refer- 
ring to  this  issue  of  The  Electrical  Ex- 
perimenter. 

Q.R.M. 

There  is  not  enough  space  in  this  maga- 
zine to  report  all  Q.R.M.,  but  some  of  it 
was  intentional,  and  the  writer  does  not 
care  to  stir  up  any  ill  feeling  by  publish- 
ing it.  If  you  are  interested  in  knowing, 
however,  who  deliberately  Q.R.M.'d  the 
stations  in  Connecticut  and  Massachusetts 
at  10:35  p.m.,  the  night  of  February  24, 
1917,  write  to  1  IZ— R.  T.  St.  James,  Great 
Barrington,  Mass. 

PERFECT  SCORES. 

Below  you  will  find  the  names  of  the 
boys  and  stations  that  made  "perfect  scores." 

ARKANSAS. 
John  M.  Clayton,  5  BV,  Little  Rock 

ARIZONA. 
R.  A.  of  Arizona,  6  FD,  Phoenix 
L.  E.  Glenn,  6  IT,  Alhambra 
J.  Giraud,  6  EO,  Phoenix 
R.  Higgy,  6  DM,  Phoenix 

COLORADO. 

E.  F.  Doig,  9  ZF,  Denver 
W.  H.  Smith,  9  ZF,  Denver 

CALIFORNIA. 
Seefred  Bros.,  6  EA,  Los  Angeles 
L.  Lynde,  6  UG,  Long  Beach 

C.  H.  Hirst,  Stanford  University 

F.  Terman,  6  FT,  Stanford  University 
L.  L.  Hoyt,  6  SI  Hayward 

CONNECTICUT. 
H.  Haugh,  HH,  Derby 

DAKOTAS. 
M.  Tuve,  MT,  Canton,  S.D. 
P.  C.  Green,  PG,  Aberdeen,  S.D. 

D.  Cottam,  DCL,  La  Moure,  N.D. 

E.  Worthington,  9  APG,  Aberdeen,  S.D. 
E.  R.  Issak,  9  TZ,  Eureka,  S.D. 

A.  Shaw,  AS,  Parkston,  S.D. 

FLORIDA. 
J.  C.  Cooper,  Jr.,  Esq.,  4  EI,  Jacksonville 

C.  M.  West,  U.S.N.,  St.  Augustine 

GEORGIA. 

D.  L.  Gaston,  C\/W,  Commerce 
A.  F.  Hood,  CWW,  Commerce 


Super-Sensitive  Microphone  Only  $6 

This  instrument  is  offered  at  an  extremely  low  price.  It  is  excellent 
for  building  your  own  radio  amplifier.  Can  also  be  used  in  many 
experiments  where  a  sensitive  microphone  is  required. 

DETECTAGRAPH,  $12 

This  detecting  instrument  of  marvelous  sensitiv- 
ity can  be  used  for  detecting  secret  conversations. 
Outfit  consists  of  Sensitive  Transmitter,  25-f t. 
Black  Cord,  Receiver,  Headband.  Case  and 
Battery. 

Send  for  One  Today  and  Convince  Yourself 

M  ICROPHO-DETECTOR 
COMPANY 

GASTON  BOISSONNAULT.      -  President 


DETECTAGRAPH  $12 


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Makers  of  Super-Sensitive  Microphone  Apparatus 


Line  Space 
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and  Automatic  * 
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I  want,  through  this  advertisement, 
to  establish  as  friendly  business  rela- 
tions with  you  as  I  possibly  can.  I 
want  you  to  realize  also,  that  it  is  my 
earnest  effort  and  Intention  to  give 
you  full,  honest  value  for  every  dollar 
that  you  spend  with  me.  This  la 
the  only  way  I  can  ucceed.  My 
advertisement  has  appeared  in  thla 
magazine  continuously  for 
more  than  four  years. 

I  am  building  up  my  bus- 
iness on  the  foundation 
of  good  value  and  square 
dealings.  I  am  saving 
thousands  of  satisfied  cus- 
tomers thousands  of  dol- 
lars by  supplying  perfect 
— late  style — visible  writing — type- 
writers, at  remarkably  low  prices. 

All  my  transactions  are  handled 
throughout  by  personal  correspond- 
ence. I  assure  you  every  courtesy 
and  consideration  in  your  dealings 
with  me.  Your  order  will  have  my 
prompt,  careful,  personal  attention. 
1  will  be  glad  to  do  business  with  you. 


ALL  LATEST  IMPROVEMENTS 


✓  TYPEWRITER  SENSATION. 

Free  TRIAL — Use  as  You  Pay 

Send  me  only  $3.00  a  month  until  the  low  total  price 
of  $49.15  is  paid,  and  the  machine  is  yours 

This  is  absolutely  the  most  generous  typewriter  offer  ever  made.  Do  not  rent  a  machine  when 
you  can  pay  $3.00  a  month  and  own  one.  Think  of  it — Buying  a  $100.00  machine  for  $49.15. 
Cash  price  $46.45.    Never  before  has  anything  like  this  been  attempted. 

s5ffiP  UNDERWOOD 

Perfect  machines,  Standard  Size,  Keyboard  of  Standard  Universal  Ar- 
rangement, writing  the  full  84  characters— universally  used  in  teaching  the  touch  system. 

The  entire  line  of  writing  completely  visible  at  all  times,  has  the  inbuilt  tabulator,  with  billing 

devices,  the  two-color  ribbon — with  automatic  reverse  and  key  controlled  shift,  automatic  ,.  

flexible  paper  feed — automatic  paper  fingers  the  back  spacer — roller  bearing  carriage  action 
— in  fact  every  late  style  feature  and  modern  operating  convenience.    Comes  to  you  with 
everything  complete,  tools,  cover,  operating  book  and  instructions,  ribbon,  practice  paper 
— nothing  extra  to  buy.     You  cannot  imagine  the  perfection  of  this  beautiful 
reconstructed  typewriter  until  you  have  seen  it.    I  have  sold  several  thousand  / 
perfect  latest  style  machines  at  my  bargain  price  and  everyone  of  these  thousands  of  / 
satisfied  customers  had  the  beautiful,  strictly  up-to-date  machine  on  5  days'  free  trial  / 

before  deciding  to  buy  it.  I  will  send  it  to  you  F.  O.  B.  Chicago  for  five  days'  free  /  Ship  me  the 
trial.  It  will  sell  itself,  but  if  you  are  not  satisfied  that  this  is  the  greatest  type-  /  UNDERWOOD 
writer  you  ever  saw-,  you  can  return  it  at  my  expense.    You  won't  want  to  return    j    F.O.B.  Chicago,  as  de 


H.  A.  SMITH 

Room  738 
231  N.  Fifth  Ave. 

CHICAGO,  ILL. 


it  after  you  try  it — you  cannot  equal  this  wonderful  value  anywhere 

You  Take  No  Risk — Put  in  Your  Order  Now 

When  the  typewriter  arrives  deposit  with  the  express  agent  $7.15  and  take  the 
machine  for  five  days'  trial.    If  you  are  convinced  that  it  is  the  best  type- 
writer you  ever  saw,  keep  it  and  send  me  $3.00  a  month  until  my  bargain 
price  of  $49.15  is  paid.    If  you  don't  want  it,  returnitto  the  express  agent,  / 
receive  your  $7.15  and  return  the  machine  to  me.    I  will  pay  the  return  / 
express  charges.    This  machine  is  guaranteed  just  as  if  you  paid 
$100.00  for  it.  It  is  standard.    Over  one  hundred  thousand  people  own 
and  use  these  typewriters  and  think  them  the  best  ever  manufactured. 
The  supply  at  this  price  is  very  limited,  the  price  will  probably 
be  raised  when  my  next  advertisement  appears,  so  don't  delay. 
Fill  in  the  coupon  today — mail  to  me — the  typewriter  will  be  / 
shipped  promptly.    There  is  no  red  tape.    I  employ  no  solicitors  / 
— no  collectors — no  chattel  mortgage.    It  is  simply  understood  / 
that  I  retain  title  to  the  machine  until  the  full  $40.15  is  paid.  / 
You  cannot  lose.     It  is  the  greatest   typewriter  oppor- 
tunity you  will  ever  have.    Do  not  send  me  one  cent. 
Get  the  coupon  in  the  mails  today — sure. 


scribed  in  this  advertise- 
f    ment.    I  will  pay  you  the 
/    $42.00  balance  of  the 
/  SPECIAL  $49.15  purchase 
/   price  at  the  rate  of  $3.00 
/    per  month.    The  title  to  re- 
main in  you  until  fully  paid 
for.    It  is  understood  that  I 
have  five  days  in  which  to  ex- 
,■'    amine  and  try  the  typewriter. 
j    If  I  choose  not  to  keep  it,  I  will 
f    carefully  repack  it  and  return  it 
to  the  express  agent.     It  is  under- 
stood that  you  give  the  standard 
guarantee  for  one  year. 


Name 


HARRY  A.  SMITH 


Address . 


738-231  N.  Fifth  Avenue 


Chicago 


You  benefit  by  mentioning  "The  Electrical  Experimenter"  when  writing  to  advertisers. 


64 


THE  ELECTRICAL  EXPERIMENTER 


May,  1917 


A  Motor  and  a  Rotor  for  $5.25 

We  have  built  5000  of  these  outfits,  consisting  of  a  motor 
that  will  operate  on  a.  c.  or  d.  c,  5000  to  6000  r.  p.  m.,  100 

to  1 30  volts. 

An  aluminum  rotor,  per- 
fectly  balanced,  machined 
and  insulated. 

$4.00 

Motor  only 

$1.50 

Rotor  only 
W!-en  ordering  rotors  give  size  of  shaft 

The  Fosco  Corporation 

1355  N.  Western  Ave.,  Chicago,  111. 

Send  postage  for  catalogue  of  motors  and  supplies 


Regular  price  of 
these  outfits,  $8.50 

Introductory  offer 
as  above,  while 
they  last.  Act 
quick. 


One-half  actual  size 


The  Mark-o' Quality 

is  a  storage 
battery 


An  Opportunity  for  Experimenters 

to  secure  a  GOOD  storage  battery  at 
a  moderately  LOW  cost.  The 
ONE  article  you  cannoc 
afford  to  experi-  C^* 
ment  with  CJ^^^ 

vc9 


MARKO 

torage    batteries    are  es- 
pecially adapted  for  operation  of 
all  kinds  of  spark  coils,  insuring  a  heavy 
and  powerful  spark.    There  is  nothing  superior 
FOR  AUDION  USE 


Type 

Volts 

Amp.  H.R 

List 

Special  price  to 

Capacity 

Price 

wireless  engineers 

4C2 

4 

40 

$  7.00 

$4.90 

6C2 

6 

40 

10.00 

7.00 

6C4 

6 

60 

12.00 

8.40 

6C6 

6 

80 

16.00 

11.20 

PAUL  M.  MARKO  &  CO.,  Inc.,  1191  Bedford  Ave.,  Brooklyn,  N.Y.    N.  Y.  Depot— 974  8th  Ave.,  N.Y.City 


New  Undamped  Wave  Coupler  No.  749 

Special  Introductory  Price,  $18.00 

Our  new  coupler  No.  749  Is  32"  long,  9*  wide,  and 
10"  high,  over  all,  and  on  an  average-sized  Antenna 
tunes  to  15,000  meters.  This  coupler,  used  with  the 
new  CHAMBERS'  SYSTEM  or  CIR- 
jps      CTJJT,  will  bring  in  signalslrom  domestic 
mm       and  foreign  Arc  Stations  surprisingly 
#Bi      loud  and  clear.   Note  the  difference  in 
size  of  our  No.  748  and  No .  749. 
We  claim  to  be  the  original  inventors  of 
a  SYSTEM  or  CIRCUIT  for  the  recep- 
tion of  the  undamped  waves  without  the 
use  of  Loading  Coils  or  Oscillating  Coils, 
as  they  are  sometimes  called:  as  with  our 

SYSTEM  or  CIRCUIT  only  two  Inductively 
Coupled  Coils  are  necessary.  Circuit  supplied 
with  each  coupler. 

This  CHAMBERS'  CIRCUIT  saves  you  money, 
o  pay  for.  and  price  of  coupler  only  $18.00.  Place  order 
introductory  price.    Orders  tilled  in  rotation.    Send  for 

F.  B.  CHAMBERS  &  CO.,  2046  Arch  St.,  Phila.,  Pa. 


_  THERE'S  MONEY  IN  IT** 

T..ZT1MORSE  AND  WIRELESS"."  JHZ* 


LEARN  TELEGRAPHY^Sf^*' 


TEACH  YOURSELF 


in  half  the  usual  time,  at  trifling  cost,  with  the 
wonderful  Automatic  Transmitter,  THE  0MNIGRAPH. 

Sends  unlimited  Morse  or  Continental  messages,  at 
any  speed,  just  as  an  expert  operator  would. 

Adopted  by  U.  S.  Gov't.    4  stylet.     Catalogue  tree. 

OMNIGRAPH  MFG.  CO. 

39L  Cortlandt  St.  New  York 


C.  H.  Williams,  4  CY,  Covington 
J.  R.  Shumate,  4  EC,  Tomasville 
W.  B.  Pope,  4  AA,  Athens 
INDIANA. 

G.  Decker,  9  QNO,  Ligonier 
L.  B.  Wilcox,  9  KH,  Angola 
L.  Gehring,  9  AAS,  Bluffton 

P.  K.  Romey,  9  QR,  Columbia  City 
J.  E.  Williams,  JW,  La  Grange 

ILLINOIS. 
S.  W.  Pierson,  9  PY,  Carrolton 
R.  H.  G.  Mathews,  9  ZN,  Chicago 
E.  E.  Boynton,  9  ARA,  Sycamore 
L.  A.  Kern,  9  GY,  Matoon 

H.  Klaus,  HK,  Eureka 

R.  W.  Beard,  9.GK,  Pleasant  Plains 
E.  H.  Giddings,  9  MK,  Lanark 
H.  A.  Mackley,  9  AIM,  Peoria 
IOWA. 

W.  E.  Slauson,  9  AMI,  Monticello 
H.  O.  Ainsworth,  9  AMI,  Monticello 
S.  U.  of  Iowa,  9  YA,  Iowa  City 
Don  Bailey,  9  RD,  Clinton 
Lester  Fawcett,  9  AIF,  Independence 

C.  Tumwall,  CT,  Ottumwa 
W.  Harper,  WH,  Ottumwa 
H.  M.  Ennis,  HME,  Ottumwa 
Kent  Bros.,  9  ARF,  De  Witt 

"The  Old  War  Horse,"  9  RD,  Clinton 

KANSAS. 
W.  S.  Ezell,  9  YE,  Wichita 
Karl  Keller,  9  ADE,  Kinsley 
LOUISIANA. 
P.  E.  Grenlaw,  5  BB,  Franklinton 

MASSACHUSETTS. 
R.  T.  St.  James,  1  IZ,  Great  Barrington 
P.  C.  Smith,  Haverhill 
E.  B.  George,  1  ANA,  Framingham 
B.  H.  Moran,  1  AAM,  Natick 
MINNESOTA. 
Peter  Hansen,  PH,  Chisolm 
MICHIGAN. 
J.  L.  Munger,  LM,  Sturgis 
W.  Benson,  8  ANR,  Battle  Creek 
Ed.  Holby,  9  OE,  Marquette 
Y.M.C.A.,  8  QJ,  Ann  Arbor 
M.  B.  Rann,  8  ADR,  Lansing 
W.  Koivanen,  WK,  Chisolm 

D.  G.  Carter,  8  WR,  Grosse  Point 

MISSOURI. 
W.  Corwin,  9  ABD,  Jefferson  City 
Washington  University,  9  XV,  St.  Louis 
H.  Longmire,  Monroe  City 

B.  Emerson,  Monroe  City 

MARYLAND. 

C.  E.  King,  3  SV,  Baltimore 

E.  B.  Duvall,  3  AK,  Baltimore 
A.  P.  Smith,  3  AK,  Baltimore 

L.  W.  Passano,  Marconi  Operator,  M.  & 
M.  Co.,  Baltimore 

MONTANA. 
A.  C.  Campbell,  7  ZC,  Lewiston 

NEBRASKA. 
Bradford  Telepea,  No  Call,  Tekomah 

NEW  YORK. 
J.  N.  S  impson,  8  CM,  Rochester 
W.  C.  Ballard,  8  XU,  Ithaca 
Genesee  Radio  Station,  8  OZ,  Rochester 
Dr.  H.  E.  Fitch,  8  ZE,  Elmira 
O.  W.  Saxton,  8  FY,  Buffalo 
A.  C.  Young,  8  ARB,  Buffalo 
H.  Blower,  2  HB,  Brooklyn 
Kenneth  Briggs,  8  MG,  Rochester 
J.  Weiss,  2  FH,  Port  Washington 
G.  M.  Benas,  8  CC,  Utica 
W.  J.  Vickery,  8  SE,  Gloversville 
J.  K.  Hewitt,  2  AGJ,  Albany 

NORTH  CAROLINA. 
W.  S.  Rothrock,  4  DI,  Winston  Salem 
J.  T.  Moorehead,  JM,  Greensboro 

OHIO. 
Fred  Travis,  Defiance 
R.  Hoffman,  Defiance 

D.  Israel,  8  ANC,  Cincinnati 
G.  D.  Howsare,  8  ASG,  Eaton 

(The  balance  will  be  publisht  in  the  June  issue.) 


You  benefit  by  mentioning  "The  Electrical  Experimenter"  when  writing  to  advertisers. 


May,  1917 


THE  ELECTRICAL  EXPERIMENTER 


65 


Are  You  An  American? 


Are  you  with  the  country  or  against  it? 
If  you  own  a  radio  outfit  it  behooves  you 
as  a  patriotic  American  to  offer  your  Wire- 
less Station  to  your  country.  You  do  not 
obligate  yourself  in  any  way  by  signing  the 
blank  printed  below,  except  that  you  give 
the  Government  permission  to  operate  your 
station  at  any  time  its  officials  may  see  fit 
to  use  it. 

Thousands    of    Amateurs    have  thus 


pledged  their  stations,  WHY  NOT  YOU? 
Sign  the  blank  tb-day,  and  it  will  be  prompt- 
ly forwarded  to  Washington.  ( See  also 
page  3,  this  issue.)  Join  the  Radio  League 
of  America;  no  fees,  no  dues  to  be  paid. 
By  joining  you  get  a  free  membership  cer- 
tificate printed  in  green  and  gold.  Send 
stamp  for  large  eight  page  information 
booklet.  Radio  League  of  America,  233 
Fulton  Street,  New  York  City. 


■  nit  111  ■  1 111  j  iikiiic^  iiifiiiiiiiiisiiiiii  iicr^iiiii  1  1  iiicsitiiciiiiniii  iiiiiiiiriiiicjiiiiiiii  11  inita  111  ruin 

Application  for  Membership  in  the 

Radio  League  of  America  j 

I     "Kt  THE  UNDERSIGNED,  a  Radio  Amateur,  am  the  owner  of  a  Wireless  | 

I      /II      Station  described  in  full  on  the  face  of  this  application.     My  station  = 

§              has  been  in  use  since  ,  and  I  herewith  de-  § 

I      sire  to  apply  for  membership  in  the  RADIO  LEAGUE  OF  AMERICA.  | 

I      I  have  read  all  the  rules  of  the  LEAGUE,  and  I  hereby  give  my  word  of  | 

5      honor  to  abide  by  all  the  rules,  and  I  particularly  pledge  my  station  to  the  5 

5      United  States  Government  in  the  event  of  war,  if  such  occasion  should  E 

3      arise.  p 

i             I  understand  that  this  blank  with  my  signature  will  be  sent  to  the  = 

§      United  States  Government  officials  at  Washington,  who  will  make  a  record  i 

I      of  my  station.  = 

E               Witnesses  to  signature:                  Name   H 

I                                                                                  City     I 

I                                                                               State   I 

I                                                                               Date  191  | 

E                  Describe  the  apparatus  of  your  station  on  the  blank  below.  e 

I             In  the  event  of  national  peril,  you  will  volunteer  your  services  as  a  E 

^      radio  operator  in  the  interest  of  the  U.  S.  Government?   = 

I              This  last  question  need  not  be  answered  unless  you  so  desire  it.  | 

I           Description  of  My  Station  and  Apparatus  | 

i     Sending   E 

§      Receiving    E 

I                                                                                                               (5-17)  I 

P.iiiiiiiiiiiiiiiiiinimiiiiiiinc:  iiiiiiiiiiiiiiiiiiiMiiiiicaiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiEaiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiicaiiiiiiiiiniiiiiiiiiiiiiiiiiiiiiEaiiiiiiiiiiiiiiiiiiiiiiiiiiii^ 

CUT  OUT,  FILL  IN,  AND  RETURN  AT  ONCE 


DISTRIBUTED  CAPACITY  AND  ITS 
EFFECT. 

(Continued  from  page  33) 

of  the  June  1916  issue  of  this  journal.  For 
those  who  have  not  seen  this  copy,  the 
accompanying  reproduction  is  made,  Fig.  5. 
The  construction  is  very  simple  and  the 
drawing  is  self-explanatory. 

The  effect  of  distributed  capacity  and 
dead-end  effect  is  more  pronounced  in  long 
coils  and  it  is  advisable  to  wind  such  coils 
in  sections  as  shown  in  Fig.  6.  It  has  been 
found  that  a  considerable  amount  of  dis- 
tributed capacity  is  eliminated  by  such  a 


method  of  winding  and  it  should  be  done 
in  every  case  where  it  is  possible,  especially 
on  secondaries  of  loose  couplers.  The 
reason  for  reducing  the  distributed  capac- 
ity is  self-apparent,  as  the  capacity  varies 
inversely  as  the  thickness  of  the  dielectric 
between  the  conducting  mediums.  Thus  the 
capacity  is  reduced  by  increasing  the  dis- 
tance between  sections.  It  will  be  an  ideal 
inductance  if  each  turn  of  the  coil  is  sepa- 
rated from  its  neighboring  turn,  say,  one- 
thirty-second  of  an  inch  each.  The  distri- 
buted capacity  of  such  a  coil  would  be  very 
small  as  compared  to  a  coil  with  the  wires 
close  together. 


"  You  Get  The  Job" 

"We've  been  watching  you, 
young  man.  We  know  you're 
made  of  the  stuff  that  wins.  The 
man  that  cares  enough  about  his 
future  to  study  an  I.  C.  S.  course 
in  his  spare  time  is  the  kind  we 
want  in  this  firm's  responsible 
positions.  You're  getting  your 
promotion  on  what  you  know,  and 
I  wish  we  had  more  like  you." 

The  boss  can't  take  chances. 
When  he  has  a  responsible  job  to 
fill,  he  picks  a  man,  trained  to  hold 
it.  He's  watching  you  now,  hop- 
ing you'll  be  ready  when  the  op- 
portunity comes. 

The  thing  for  you  to  do  is  to 
start  today  and  train  yourself  to  do 
some  one  thing  better  than  others. 
You  can  do  it  in  spare  time 
through  the  International  Corre- 
spondence Schools.  Over  5000  men 
reported  advancement  last  year  as 
a  result  of  their  I.  C.  S.  training. 

The  first  step  these  men  took 
was  to  mark  and  mail  this 
coupon.  Make  your  start  the 
same  way— and  make  it  right  now. 

I.  C.  S.,  Box  53  4  6,  Scranton,  Pa. 
nNTERNATSONALloRRlsPONDENCE  SCHOOLS 

Box  534  6,  SCRANTON.  PA. 

Explain,  without  obligating  me,  how  I  can  qualify  for 
the  position,  or  in  the  subject,  before  which  I  mark  X. 


□  ELECTRICAL  ENGINEER 

□  Electric  Lighting 

_j  Electric  Car  Running 

□  Electric  Wiring 

□  Practical  Telephony 
J  Telegraph  Expert 
^MECHANICAL  ENGINEER 

□  Mechanical  Draftsman 

H Machine  Shop  Practice 
Gas  Engineer 

□  CIVIL  ENGINEER 

□  Surveying  and  Mapping 

□  MINE  KOKEM'N  OR  ENG'ft 

□  Metallurgist  or  Prospector 

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□  PLUMBING  AND  HEATING 

□  Sheet  Metal  Worker 

□  CHEMICAL  ENGINEER 

Name  


B SALESMANSHIP 
ADVERTISING  MAN 

□  Window  Trimmer 

□  Show  Card  Writer 

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□  RAILROADER 

□  ILLUSTRATOR 

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□  Cert.  Pub.  Accountant 

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□  Common  School  SnbJecU 

□  CIVIL  SERVICE 

□  Railway  Mail  Clerk 

□  AGRICULTURE 

□  Textile  OverBeer  or  Snpt. 

□  Navigator       □  Spanum 

□  Poultry  Raising  H  German 

□  AUTOMOBILES  Q  French 

□  Auto  Repairing  □Italian 


Occupation 
&  Employer. 


Street 
and  No.. 


City  . 


.  State_ 


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{Continued  from  page  21) 
as  one  of  the  fleet  when  the  war  had 
broken  out.    I  tried  to  ask  him  questions, 
but  he  was  as  clammy  as  Parker  and  I 
could  get  nothing  out  of  him. 

What  was  behind  that  locked  steel  door? 
Was  the  means  of  destroying  the  enemy's 
ships  concealed  there?  What  was  this 
curious  torpedoless  means?  I  wanted  to 
ask  Parker,  but  pride  and  shame  at  my 
own  stupidity  held  me  back.  So  I  won- 
dered and  pondered  and  puzzled  all  that 
day. 

Thought  of  the  affair  was  dispelled  when 
about  sundown  the  lookout  sighted  an 
enemy  aeroplane  dead  ahead  and  some  dis- 
tance aloft.  We  immediately  sank  to  the 
awash  condition  and  then  as  the  plane 
grew  near,  we  submerged  with  only  our 
periscope  showing.  This  we  drew  in  as 
we  noted  that  the  aeroplane  sighted  us 
and  swooped  down  for  a  look.  We  ran 
submerged  for  a  half  hour  or  so  and  then 
cautiously  poked  up  our  periscope. 

There  was  a  sudden  cry  of  warning  from 
the  man  at  the  instrument  and  we  dove 
again.  There  had  been  an  enemy  torpedo 
boat  destroper  near,  and  even  in  the  dusk 
it  was  not  safe  to  come  up  when  any  of 
these  craft  were  about.  We  had  been 
sighted  we  knew,  for  its  searchlights  made 
the  water  dimly  translucent  above  us. 
But  we  submerged  below  the  light  and  ran 
still  east  by  north. 

It  was  just  after  this  that  I  noticed  that 
Billy  came  to  the  feeler  case.  I  heard 
him  give  directions  that  the  small  alterna- 
tor which  supplied  the  coil  with  current, 
should  be  started.  Then  he  worked  the  two 
control  wheels,  and  by  glancing  over  his 
shoulder  at  the  dials  I  saw  that  he  was 
sweeping  the  coil  from  side  to  side,  and 
frequently  changing  its  inclination.  By 
this  means  he  was  throwing  out  an  arm 
of  magnetic  force  which  would  indicate  the 
position  of  any  enemy  ship  within  ten 
thousand  yards. 

"Hunting  for  fish?"  I  asked. 

"Yes,  I'm  feeling  for  them,"  he  an- 
swered, watching  the  angle  of  the  hori- 
zontal gage,  and  then  turning  to  me  with 
a  twinkle  in  his  eye.  "Have  you  solved 
it  yet?" 

"No,  I  haven't,"  I  admitted. 

"You  watch  tonight  then,"  he  said. 
"We're  about  due  to  be  in  the  enemy's 
fleet  and  we  ought  to  have  some  experience 
at  least." 

The  light  on  the  case  before  him  flashed 
suddenly  red,  and  the  dial  needle  marking 
distance  jumped  up  to  eight  thousand  and 
stopt  there.  He  turned  and  held  the  hori- 
zontal control  wheel  stationary  a  mo- 
ment. 

"We're  in  them  now,"  he  said.  "There's 
the  first  one." 

There  followed  a  most  wonderful  piece 
of  maneuvering.  He  turned  the  coil  until 
he  was  sure  of  the  position  of  the  enemy, 
and  then  changed  the  course  of  our  boat 
to  correspond  to  his.  Slowly  we  worked 
around,  the  little  coil  giving  us  the  posi- 
tion of  our  foe  with  its  unerring  magnetic 
touch. 

In  half  an  hour  we  were  making  twenty- 
two  knots  west  by  south  and  running  thirty 
feet  under.  The  enemy  was  off  to  star- 
board according  to  our  indicator. 

"He  must  be  a  battleship.  Twenty-two 
is  too  slow  for  anything  else,"  Billy  said. 

I  agreed  and  a  moment  later,  with  a 
final  assurance  that  our  courses  were 
parallel,  Billy  turned  to  a  locked  case  be- 
side the  feeler  box.  I  glanced  at  the  dial. 
The  enemy  was  just  1436  yards  away  ac- 
cording to  our  readings. 

Billy  was  opening  the  case  which  looked 
exactly  similar  to  the  feeler,  but  lacked 
the  lamp  and  distance  dial  and  had  only 


two  control  wheels.  Under  it  was  a  small 
electric  pushbutton  whose  function  I 
could  not  understand. 

He  twisted  the  control  wheels  for  a 
moment  until  the  dials  read  the  same  as 
those  of  the  feeler.  Then  he  called  down 
the  speaking  tube. 

"Start  the  alternator." 

"Yes,  sir,"  came  back  Dickenson's  reply. 

I  heard  faintly  above  the  other  ma- 
chinery the  starting  crescendo  of  a  turbine. 

"Here  goes  for  a  trial,"  Billy  said. 

I  watched  him,  and  with  a  final  glance 
to  make  sure  that  both  dials  corresponded, 
he  deprest  the  button.  The  machine  for- 
ward, the  alternator,  I  thought,  dipt  sev- 
eral notes  in  its  hum  and  then  rallied.  The 
button  was  down  for  four  or  five  minutes 
and  then  he  let  it  up  and  gave  the  com- 
mand to  stop  the  alternator. 

What  had  he  done?  Had  this  deprest 
button  let  loose  some  mysterious  new  force, 
some  wonderful  ray,  some  hitherto  un- 
discovered etherial  vibrations  which  could 
travel  through  water  and  destroy  the  enemy 
ship  alongside  us?  What  had  he  done  when 
he  prest  that  button?  I  wanted  to  ask 
him,  but  again  pride  and  chagrin  stopt 
me. 

Instead  I  went  to  my  instruments,  think- 
ing that  I  might  pick  up  some  of  the 
enemy's  talk  and  hear  something  worth 
knowing.  To  this  purpose  I  juggled  my 
tuner  knobs,  getting  many  and  rapidly 
changing  combinations  with  the  sliding 
contacts. 

It  was  while  doing  this  that  I  heard  a 
sudden  loud  buzz  in  the  receiver.  I  held 
the  adjustment  there  a  moment  and  heard 
several  letters,  apparently  forming  a  for- 
eign word.  Then  I  listened  while  a  mes- 
sage in  the  enemy's  tongue  was  spelled 
off  loudly  into  my  receiver.  I  wrote  it 
down  as  it  came.  When  it  had  stopt  and 
I  had  translated  it,  I  had  before  me  the 
following : 

"The  fire  in  the  forward  port  compart- 
ment, No.  7,  is  in  the  oil  tanks  and  is  so 
hot  that  it  has  melted  out  a  section  of  the 
hull  plates.  We  have  a  heavy  list  to  port, 
but  are  not  in  immediate  danger.  Good 
luck. 

"Captain  Von  Heissburg, 

"The  Stoltzenfels." 

That  looked  as  if  there  was  trouble  in 
one  of  the  enemy's  ships.  I  showed  the 
message  to  Billy. 

He  read  it  over  twice  and  then  glanced 
up  with  a  gratified  light  in  his  face. 

"Pretty  good,  but  not  quite  enough,"  he 
said.  "Have  to  use  more  next  time  I 
guess,"  and  he  turned  away  to  the  feeler 
case. 

I  could  make  nothing  of  this  remark 
and  did  not  try  to.  I  was  too  busy  watch- 
ing him  again. 

Once  more  he  was  sweeping  with  the 
feeler.  We  were  bearing  off  to  the  south 
and  running  slowly.  Again  the  light 
flashed  and  he  twisted  controls  and  helm 
until  we  ran  parallel  with  the  enemy.  43 
yards  away  and  off  his  starboard  side. 
Once  again  we  were  thirty  feet  under  and 
running  at  twenty-two  knots,  which  seemed 
to  be  the  speed  of  the  fleet.  As  before 
Billy  twisted  the  controls  on  the  other  and 
un-named  case  until  the  dials  read  the  same 
as  the  feeler.  Once  again  he  called  the 
order  to  start  the  alternator.  The  hum  of 
the  machine  sounded  and  as  before  the 
button  was  prest.  I  timed  it  now  and 
found  that  it  was  held  down  six  and  a 
half  minutes. 

Then  we  sheered  off  to  the  south,  slow- 
ing up  and  letting  the  enemy  pass  ahead 
of  us. 

I  watched  again  in  intense  but  unsatis- 
fied curiosity  while  Billy  twisted  and 
and  turned  the  little  wheels  and  after  our 
boat  came  parallel  to  the  enemy,  prest  the 


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May,  1917 


THE  ELECTRICAL  EXPERIMENTER 


67 


button  after  having  the  alternator  started. 

Fourteen  more  times  it  happened  that 
night,  while  we  maneuvered  and  changed 
our  course  to  get  into  position.  I  did  not 
get  a  chance  to  ask  him  that  night.  He 
was  busy  and  the  gratified  light  was  too 
strong  in  his  face,  and  I  knew  from  all 
signs  that  I  would  only  encounter  more 
teasing. 

So  I  stood  by  and  watched  and  wondered 
what  mysterious  force  was  being  loosed 
when  he  prest  that  button.  Was  ii  inten- 
sified wireless  waves?  I  listened  at  my 
receivers  once  to  make  sure  of  this  theory, 
but  heard  nothing.  So  I  gave  it  up  and 
watched  and  waited  to  let  him  tell  me  in 
his  own  way  at  his  own  time. 

The  next  morning  we  had  cruised  foi 
two  hours  without  catching  anything  in  the 
meshes  of  our  magnetic  net  and  Billy  was 
about  to  give  the  order  to  come  to  the  sur- 
face when  we  picked  up  something  off  our 
port  bow.  We  slowed  down  to  fall  in  with 
it,  since  it  seemed  to  be  running  slower 
than  we.  After  a  few  moments  we  found 
that  it  was  stationary.  We  ran  around  it 
three  times  and  then  running  several  hun- 
dred yards  away  from  it,  Billy  gave  the 
order  to  come  up  cautiously. 

The  rising  periscope  flasht  the  picture, 
the  scene  that  was  there,  spread  on  the 
water  in  the  early  morning  light.  I  saw 
it  over  Billy's  shoulder  in  the  mirror. 

It  was  a  proud  battleship,  or  had  been, 
now  leaning  far  over  to  port  and  sur- 
rounded by  a  bevy  of  small  boats  filled  to 
overflowing  with  men.  The  great  guns 
were  pointing  wryly  skyward,  and  gave  it  a 
ridiculously  helpless  air  as  it  lay  there, 
rolling  heavily  in  the  swell  of  the  «ea. 

"Its  the  Stoltzenfels,"  Billy  said,  look- 
ing intently  into  the  mirror. 

Then  I  remembered  the  message  from 
her  captain  which  I  had  overheard  last 
night.  I  was  about  to  mention  this  when 
I  saw  that  the  men  in  the  boats  had 
sighted  us  and  were  now  pointing  to  us 
and  signaling  to  the  battleship.  One  of 
the  great  turrets  swung  about  drunkenly 
and  then  we  dove.  We  ran  under  the  ship 
and  her  boats  and  then  away  to  the  west. 

"Let  them  go.  They  can't  hurt  anything 
with  that  leaky  tub.  That's  the  one  we 
experimented  on  and  didn't  give  enough 
to,"  Billy  said. 

We  ran  that  morning  with  our  periscope 
and  breather  pipes  out  of  water,  but  ready 
to  sink  unseen  if  necessary.  We  saw  noth- 
ing of  the  enemy,  but  about  nine  o'clock 
while  at  the  receivers  I  caught  this  mes- 
sage : 

"Captain  Rollins,  U.S.X.  Aviation  Corps. 
Have  sighted  much  wreckage  and  hun- 
dreds of  enemy  boats  filled  with  men.  Also 
life  rafts  and  other  floating  objects  with 
men  clinging  to  them.  Sighted  the  Stolt- 
zenfels leaking  badly,  and  with  many  boats. 
Caught  glimpse  of  few  transports  but  kept 
away  by  destroyers.  Send  cruisers  and  de- 
troyers  out  at  once.  Battleships  seem 
lost.  Lieutenant  Fletcher,  Aviation  Corps 
No.  7." 

This  I  knew  came  from  the  wireless  of 
one  of  our  big  scoutplanes  which  had  been 
sent  out  to  watch  the  movements  of  the 
enemy  fleet. 

I  showed  it  to'  Billy  Parker.  He  read 
it  and  his  face  lit  with  satisfaction  in  spite 
of  the  fatigue  of  the  sleepless  night. 

"Good,"  he  shouted,  "we  got  them  all 
right,  didn't  we?  We  got'em,  the  country's 
saved,  we  got'em  ! !    We  got'em  ! ! !" 

He  capered  about  in  the  mess  room,  in 
a  manner  quite  unbecoming  for  an  officer 
and  a  man  of  his  years. 

"But  how  did  you  do  it?"  I  begged,  fol- 
lowing him  about  in  his  joyous  antics,  and 
daring  to  broach  this  subject  again  in  the 
face  of  his  good  humor. 


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THE  ELECTRICAL  EXPERIMENTER 


May,  1917 


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City_ 


"You  poor  stupid  blockhead,"  he 
laughed,  slapping  me  on  the  back,  "don't 
you  see  yet?" 

"No,  I  don't  see  at  all,"  I  admitted. 

"Let  me  tell  you  so  you  can  wireless  the 
whole  thing  back  to  the  papers.  You 
understand  how  that  feeler  works?" 

"Yes,  perfectly,"  I  said. 

"Well,  up  on  the  bow  we  have  a  big  coil 
just  like  that,  mounted  on  a  universal  joint 
so  it  can  be  raised  or  lowered  or  swung 
around  at  any  angle  in  the  vertical  or  hori- 
zontal, except  directly  back.  That  coil  takes 
about  two  thousand  kilowatts  of  current 
which  is  supplied  to  it  by  a  big  alternator 
put  in  the  old  torpedo  room  forward." 

He  paused. 

"Well?"    I  demanded. 

"Don't  you  see  now?"  he  asked. 

"No,  I  don't,  go  on,"  I  commanded. 

"Oh,  man,  you  haven't  a  bit  of  imagina- 
tion," he  groaned. 

"Well,  we  can  swing  this  coil  around 
and  send  a  current  thru  it,"  he  went  on. 
"If  an  enemy  ship  comes  within  one  hun- 
dred yards  of  us,  the  same  thing  will  hap- 
pen that  happens  in  an  induction  furnace. 
We  can  send  enough  eddy  currents  thru 
his  hull  to  melt  out  a  whole  section  of  the 
plates.    Now  do  you  understand?" 

But  I  was  at  the  key,  pounding  out  the 
message. 


COMBATING  THE  TORPEDO. 

(Continued  from  page  11) 

hand  on  Detonator  switch  No.  1,  he  calm- 
ly waits.  When  the  hostile  torpedo  is  but 
ten  feet  distant  from  motor  torpedo*  No.  1, 
he  throws  the  switch.  There  is  a  terrific 
explosion  and  a  huge  column  of  water  is 
thrown  up  several  hundred  feet  into  the  air. 
Motor  torpedo  No.  1  has  vanished,  so  has 
the  enemy  torpedo.  The  ship  for  the  time 
being  is  safe.  Instantly  the  crew  has  low- 
ered away  a  new  motor  torpedo  to  take 
the  place  of  the  one  just  destroyed  and 
long  before  it  touches  the  water  it  has  been 
electrically  connected  to  the  control  board. 
But  this  would  be  necessary  only  for  a 
large  ship  with  a  very  valuable  cargo.  A 
small  steamer  would  have  enough  torpedoes 
left  to  cope  with  the  enemy.  By  this  time, 
too,  enough  time  has  elapsed  for  the  ship 
to  alter  its  course  and  run  in  a  zig-zag 
line,  making  it  very  difficult  for  a  subma- 
rine commander  to  hit  the  fleeing  vessel 
with  the  next  torpedo.  But  in  case  of 
necessity  the  other  motor  torpedoes  are 
still  "in  the  ring"  to  successfully  grapple 
with  the  enemy.  Even  where  two  torpe- 
does are  sent  simultaneously  against  the 
ship  the  scheme  will  work  out  satisfactori- 
ly. In  that  case  the  operator  at  the  con- 
trol-board simply  has  to  work  two  rheo- 
stats and  two  detonator  switches  instead  of 
one  and  given  a  level  head  and  a  good  eye 
for  calculating  distances  and  speeds,  the 
task  is  not  such  a  very  difficult  one. 

There  are  a  number  of  firing  positions 
and  schemes  and  while  as  a  rule  only  one 
motor  torpedo  would  be  used  to  destroy  the 
enemy  torpedo,  Fig.  1  shows  how  two  mo- 
tor torpedoes  could  be  brought  close  to- 
gether (see  dotted  lines  of  No.  1)  to  inter- 
cept the  deadly  missile.  In  that  case  torpe- 
does No.  1  and  No.  2  would  be  freed  si- 
multaneously and  leave  little  chance  for  the 
enemy  torpedo  to  escape. 

It  is,  however,  not  always  absolutely 
necessary  to  actually  destroy  the  hostile 
torpedo.  Suppose  that  the  submarine  fires 
from  a  close  range,  and  suppose  that  the 
selected  motor  torpedo  cannot  be  speeded 
up  fast  enough — even  by  overloading  its 
motor  100  per  cent  by  raising  its  voltage 
— to  come  closer  to  the  enemy  torpedo 
than,  say,  thirty  feet.  Even  in  such  an 
extreme  case — tho  quite  possible  in  rough 
weather — the  control  operator  fires  his  tor- 
(Continued  on  page  70) 


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May,  1917 


THE  ELECTRICAL  EXPERIMENTER 


69 


Edited  by  H.  GERNSBACK 

In  this  Department  we  publish  such  matter  as  is  of  interest  to  inventors  and 
particularly  to  those  who  are  in  doubt  as  to  certain  Patent  Phases.  Regular  in- 
quiries addrest  to  "Patent  Advice"  cannot  be  answered  by  mail  free  of  charge. 
Such  inquiries  are  publisht  here  for  the  benefit  of  all  readers.  If  the  idea  is 
thought  to  be  of  importance,  we  make  it  a  rule  not  to  divulge  details,  in  order  to 
protect  the  inventor  as  far  as  it  is  possible  to  do  so. 

Should  advice  be  desired  by  mail  a  nominal  charge  of  $1.00  is  made  for  each 
question.  Sketches  and  descriptions  must  be  clear  and  explicit.  Only  one  side  of 
sheet  should  be  written  on. 


SAFETY-FIRST  OIL  CAN. 

(144.)  John  Brent  Marshall,  Cincinnati, 
Ohio,  submits  drawing  and  description  of  a, 
what  he  calls,  safety-first  oil  can,  and  wants 
to  know  if  it  can  be  patented. 

Ans.  The  idea  as  submitted  contains 
nothing  new  to  our  mind  and  we  are  quite 
positive  that  no  patent  can  be  obtained  on  it. 

LIGHT  DIMMER. 

(145.)  Arthur  Norris,  Defiance.  Ohio,  has 
submitted  a  light  dimmer  which  acts  on  the 
principle  based  upon  the  rotary  potentiome- 
ter, the  idea  being  to  place  a  high  resistance 
between  supply  wires  and  the  light. 

Ans.  This  is  a  very  good  idea  and  we 
are  quite  certain  that  the  device  can  be  pat- 
ented. We  have  never  seen  anything  like 
it  on  the  market  and  providing  the  device 
can  be  made  cheap  enough  and  incorporated 
in  a  lamp  socket,  there  should  exist  a  good 
demand  for  same.  We  would  advise  our 
correspondent  to  get  in  touch  with  a  patent 
attorney  at  once. 

SPARK  PLUG. 

(146.)  Clarence  Melotz,  Florence,  Neb., 
submits  what  he  calls  a  sootproof  spark 
plug.  The  arrangement  is  such  that  the 
spark  is  supposed  to  keep  a  small  cup  from 
carrying  carbon.    Our  advice  is  asked. 

Ans.  There  does  not  seem  to  be  anything 
new  contained  in  this  and  at  the  present 
time  there  is  a  very  similar  spark  plug  on 
the  market  under  the  trade  name  of  the 
"Soot-proof"  spark  plug. 

PROPELLER. 

(147.)  Alison  J.  Kurth,  Colorado  Springs, 
Col.,  encloses  sketch  and  description  of  a 
propeller  for  motor-driven  boats.  Instead 
of  using  a  propeller,  a  certain  perforated 
disc  is  used  and  our  correspondent  would 
like  to  know  if  we  advise  him  to  have  it 
patented. 

Ans.  While  this  propeller  no  doubt  works, 
it  is  impossible  to  determine  its  efficiency 
without  actually  testing  it  out,  in  practice. 
It  is  very  doubtful  to  our  mind,  however,  if 
this  propeller  should  be  more  efficient  than 
the  regular  one.  In  the  absence  of  actual 
tests,  we  would  not  like  to  finally  commit 
ourselves  and  advise  our  correspondent  to 
try  out  the  device  in  practice  before  apply- 
ing for  patent. 

AUTOMATIC  VOICE  RECORDER. 

(148.)  Joseph  Prochaska,  Chicago,  111., 
submits  to  us  drawings  and  specifications 
of  a  novel  idea,  particularly  for  use  by 
physicians  whereby  it  is  possible  for  a 
patient  to  call  up  the  doctor  while  he  is 
not  at  home  and  instead  of  the  doctor 
answering,  the  phonograph  does  this  for 
him,  all  automatically,  telling  the  patient 
where  the  doctor  can  be  located  or  when 
he  will  return. 

Ans.  The  device  is  well  worked  out  and 
while  there  does  not  exist  an  urgent  de- 
mand for  this  invention,  there  is  no  doubt 
quite  a  number  of  people  who  would  be 


interested  in  owning  such  an  apparatus.  We 
think  a  patent  might  be  obtained  upon  the 
mechanical  features  embodied  in  this  device. 


"PERPETUAL  MOTION." 

(149.)    Percy  Muirhead,  Dayton,  Wash., 
submits  a  scheme  of  "Perpetual  Motion"  in 
which  is  utilized  a  Radiometer  which  as 
.is  known,  works  by  light  striking  it.  He 
wants  our  opinion  of  this  scheme. 

Ans.  There  is  no  such  thing  as  "Per- 
petual Motion"  and  by  using  a  Radiometer, 
this  rule  is  no  exception,  for  the  simple 
reason  that  the  Radiometer  employs  light 
which  is  a  form  of  energy,  and  for  this 
reason  the  scheme  cannot  be  termed  "Per- 
petual Motion"  and  no  patent  could  be  ob- 
tained on  the  idea. 


WINDOW  ATTRACTION. 

(150.)  L.  E.  Summerton,  Maryville. 
Tenn.,  has  submitted  to  us  a  window  at- 
traction and  he  vould  like  to  know  if  it  is 
worth  while  patenting.  Also  if  there  is 
a  ready  sale  for  such  a  device.  The  idea 
consists  of  an  electrical  arrangement  where- 
by a  small  artificial  bird  acts  as  a  wood- 
pecker, pecking  against  a  piece  of  wood 
every  few  seconds. 

Ans.  This  is  a  very  good  idea  and  by 
elaborating  it  a  little  more,  we  are  quite 
certain  there  would  be  a  good  market  for 
a  thing  of  this  sort.  By  using  a  plurality 
of  birds,  a  very  interesting  window  attrac- 
tion would  be  had. 


WAVE  MOTOR. 

(151.)  C.  Mattison,  Oakland,  Calif.,  sub- 
mits drawing  and  description  of  a  wave 
motor  to  be  used  in  the  ocean  to  utilize 
the  power  of  the  waves.  He  wants  to 
know  what  we  think  of  it  and  whether  it 
is  practical. 

Ans.  _  There  is  nothing  new  contained 
in  the  idea,  which  is  not  a  good  way  of 
solving  the  problem.  The  first  requisite 
necessary  for  a  good  wave  motor  is  that 
it  must  automatically  adjust  itself  to  the 
•  various  water  levels  as  the  tide  rises  or 
falls.  Such  an  idea  was  shown  in  our 
February  issue  from  which  it  will  be  read- 
ily seen  that  the  device  will  of  necessity 
have  to  be  somewhat  complicated  for  best 
results. 


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COMBATING  THE  TORPEDO. 

{Continued  from  page  68) 
pedo  anyway.  The  result  is  such  a  terrific 
as  well  as  instant  disturbance  in  the  water 
that  the  enemy  torpedo  will  be  certainly 
deflected  sufficiently  from  its  original  course 
so  as  to  make  it  ineffective.  And  after  all, 
this  is  what  we  want.  For  the  enemy  tor- 
pedo once  it  is  spent,  sinks  automatically, 
because  to  leave  it  roam  about  the  sea 
would  constitute  as  much  danger  to  its 
own  submarine  as  to  the  attackt  vessel. 

All  the  technical  points  have  been 
worked  out  satisfactorily  and  while  the 
basic  idea  can  and  will  be  no  doubt  im- 
proved upon,  the  reader  can  form  his  own 
opinion  as  to  the  practicability  and  effect- 
iveness of  the  scheme. 

The  main  point  in  its  favor  is  that  each 
torpedo  can  be  built  at  a  cost  of  less  than 
$1,000.  For  ten  units  this  makes  a  cost  of 
less  than  $10,000  for  a  ship  of  600  feet. 
This  is  pretty  cheap  insurance,  consider- 
ing that  the  cargo  alone  on  such  a  ship 
nearly  always  is  worth  from  three-quar- 
ters to  one  million  dollars  and  often  con- 
siderably more.  The  ship  itself  costs  as 
much  again.  Besides  if  the  vessel  is  pro- 
tected adequately,  the  maritime  insurance 
is  reduced  largely  and  no  big  bonuses  need 
be  paid  to  the  crew,  as  is  the  case  now. 

The  speed  of  the  ship  is  not  reduced  by 
the  motor  torpedoes  either,  as. they  run  in- 
dependently, nor  is  the  power  to  operate 
them  very  great.  For  ten  torpedoes  we 
require  but  100  to  150  horse-power — a 
trifling  amount  for  a  600-foot  steamer  de- 
veloping some  20,000  to  30,000  horse-power. 

Nor  are  the  motor  torpedoes  used  dur- 
ing the  entire  trip.  Thus  during  a  cloudy, 
dark  night,  during  a  fog,  or  in  a  very  heavy 
sea  there  is  no  need  for  them,  as  a  sub- 
marine cannot  successfully  torpedo  a  ship 
in  such  cases. 

During  these  periods  the  motor  torpe- 
does are  hoisted  out  of  the  water  by  means 
of  their  steel  covered  cables  and  are  lashed 
fast  to  the  decks  till  needed. 

As  the  torpedoes  are  fired  by  electricity, 
there  is  little  danger  from  an  accidental 
explosion,  even  if  they  should  bump  against 
the  side  of  the  ship  occasionally,  for  in- 
stance during  launching  or  in  a  squall.  The 
distance  of  50  feet  of  the  motor,  torpedoes 
from  the  mother  ship  is  necessary,  for  if 
they  are  exploded  at  a  closer  range  than 
30  feet  they  will  damage  the  ship. 

That  the  submarine  commander  sees  the 
brightly  colored  torpedoes  does  not  matter 
in  the  least.  For  he  will  soon  learn  that 
firing  torpedoes  at  a  ship  thus  protected 
is  a  waste  of  time  and  material.  And  then 
until  something  better  is  found,  submarine 
warfare,  to  a  large  extent,  will  sink  into 
a  stalemate.   And  this  is  what  we  all  desire. 

A  ship  equipt  with  guns  (to  prevent  the 
submarine  from  using  its  own  guns)  and 
equipt  with  motor-torpedoes  as  well  stands 
little  chance  of  being  sunk. 

It  should  be  noted  that  our  cover  design 
is  not  strictly  correct.  First,  the  motor-tor- 
pedoes in  practise  run  almost  entirely  sub- 
merged, leaving  only  part  of  the  mast  ex- 
posed. Secondly,  the  submarine  is  shown 
very  much  too  close  to  the  ship.  These 
slight  technically  incorrect  points  were  nec- 
essary to  bring  out  the  idea  from  an  ar- 
tistic standpoint.  , 

GLADSTONE     AND     THE  TELE- 
PHONE. 

The  mental  fatigue  which  would  follow 
the  introduction  of  the  telephone  was  fore- 
seen by  the  late  Mr.  Gladstone,  England's 
grand  old  man.  When  he  was  asked  by 
Mr.  Edison's  representative  whether  he 
would  like  to  have  a  telephone  apparatus 
set  up  in  his  house,  he  wrote  on  a  post- 
card :  "Sir,  my  means  of  communication 
from  without  inwards  are  already  equal  to 
my  needs  and  in  excess  of  my  desires." 


MAGNETISM  PRODUCES  RE- 
MARKABLE PHOTOGRAPHS. 

{Continued  from  page  14) 

like  a  line  of  latitude,  no  mere  arrange- 
ment of  the  molecules  of  a  magnet,  can 
account  for  the  result.  There  must  be 
motion — currents  of  ether,  for  there  is  only 
ether  under  the  receiver. 

A  detailed  examination  of  the  articles 
will  strenghten  this  proof.  The  articles  are 
lettered  somewhat  in  the  order  in  which 
the  impression  is  made  on  the  plate.  Note 
that  at  A,  but  little,  if  any,  impression  is 
made  on  the  plate — the  currents  could  not 
penetrate — while  J  and  K  hardly  show  at 
all  because  the  currents  past  thru  them 
and  affected  the  plate;  and  to  pass  thru 
or  to  penetrate  there  must  be  motion — 
currents.  From  A  to  K,  it  will  be  noted 
that  the  effect  on  the  plate  grows  gradually 
stronger,  showing  that  some  are  more  pene- 
tratable  than  others  and  this  degree  of 
penetration  implies  motion.  Note  that  D, 
E  and  F  are  penetrated  less  than  G,  and 
that  G  is  penetrated  irregularly,  plainly 
showing  the  location  of  the  acid  pits  on  the 
surface  of  the  zinc.  None  of  these  effects 
could  be  produced  by  light.  Again,  B  and 
C  are  iron  weights  with  cavities  in  the  bot- 
toms and  openings  thru  the  sides  of  these 
cavities.  The  weights  were  placed  on  the 
plates  so  that  the  cavities  were  downward. 
Yet  these  cavities  show  plainly  in  the  plate. 
Light  could  not  produce  this  effect,  for  in 
any  event  it  would  produce  a  shadow  and 
enough  light  could  not  enter  the  small  open- 
ing to  effect  the  plate  practically  as  much 
as  the  exterior.  But  currents  of  ether  fol- 
lowing the  lines  of  the  iron,  as  is  the  well 
known  effect  of  iron  in  a  magnetic  field, 
could  and  did  produce  this  result.  More- 
over, careful  measurements  show  that  the 
cavities  are  a  little  larger  and  the  circum- 
ferences of  the  weights  as  shown  in  the 
plates  are  a  little  less,  than  in  the  weights 
themselves,  conforming  to  the  well  known 
deflection  or  bending  of  lines  in  a  magnetic 
field  by  the  presence  of  iron.  But  the 
crowning  proof  is  in  H.  Here  is  a  wooden 
button  showing  the  grain  of  the  wood.  The 
wood  was  penetrated  more  in  some  parts 
than  in  others.  Light  could  not  produce 
this  effect  for  it  could  not  penetrate  the 
wood  and  if  it  were  supposedly  possible  to 
bring  to  bear  light  strong  enough  to  pene- 
trate the  button,  it  would  penetrate  all 
parts  equally.  The  cracks  and  seams  in 
J  and  K  are  shown  in  the  same  manner  but 
in  a  less  degree.  Here  then  is  unques- 
tionably penetration,  and  penetration  can 
not  possibly  take  place  without  motion. 
Who  would  now  question  the  existence  of 
currents  about  the  magnet? 

Furthermore,  here  is  incontestable  proof 
that  the  lines  of  force,  lines  of  tension, 
mere  lines  of  direction  do  not  "emerge 
from"  (without  motion)  the  North  pole  of 
the  magnet,  nor  "pass  to  or  enter"  (again 
without  motion),  the  South  pole.  The 
effect,  the  penetration,  the  currents  are 
equal  over  both  poles.  These  currents  pass 
into  both  poles  alike.  They  do  not  pass 
out  from  the  poles  for  the  plate  is  above 
the  poles,  both  poles,  with  the  sensitive 
side  upward,  and  the  objects  are  on  the 
sensitive  side  of  the  plate  above  the  poles. 
If  the  currents  were  passing  upward  from 
either  pole,  there  would  be  no  impression 
on  the  plate  over  that  pole,  for  the  current 
would  oass  thru  the  sensitive  film  before 
reaching  the  objects.  Instead,  it  shows 
plainlv  that  the  currents  past  poleward 
equally  over  both  poles,  penetrated  more  or 
less  the  objects  on  tne  plate,  affected  the 
sensitive  plate  more  or  less  according  to 


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THE  ELECTRICAL  EXPERIMENTER 


7i 


the  amount  of  penetration,  and  then  past 
on  to  the  magnet.  What  then  becomes  of 
them  will  be  shown  later. 

Still  there  are  doubters.  Could  the  re- 
sult be  due  to  stray  light?  Could  it  be 
due  to  phosphorescence?  To  radio-activ- 
ity? Could  the  same  result  be  obtained 
without  the  magnet?  To  answer  these  I 
placed  a  plate  over  a  wooden  "U"  under 
the  receiver,  with  the  objects  placed  updn  it 
exactly  as  before  and  used  exactly  the  same 
precautions  as  in  the  first  instance.  At 
the  same  time  and  in  the  same  room,  far 
enough  away  not  to  effect  the  plate  under 
the  receiver,  I  placed  a  plate  over  the  mag- 
net with  several  objects  upon  it,  but  with- 
out a  receiver,  placed  a  light-tight  box  over 
this,  and  covered  the  whole  with  heavy 
folds  of  black  cloth.  In  this  instance  the 
room  was  not  opened  for  twenty-two  days. 
At  the  end  of  that  time  both  plates  were 
developed  with  equal  care  under  the  same 
conditions  as  in  the  first  case.  The  plate 
over  the  wooden  support  under  the  re- 
ceiver was  a  perfect  blank!  There  was  no 
impression  on  it.  The  result  with  the  plate 
over  the  magnet  in  the  air  is  shown  in 
Fig.  4.  In  this  A  is  a  key,  B  and  C  are 
pearl  buttons,  and  D,  E  and  F  are  wooden 
buttons.  The  grain  of  the  wooden  but- 
tons can  be  seen  as  in  Fig.  3  showing  that 
the  penetration  is  the  same  here  but  the 
whole  plate  demonstrating  that  the  result 
is  somewhat  less  clear,  as  might  be  ex- 
pected, in  the  air  than  under  *a  vacuum. 
The  difference  in  the  penetration  at  D  and 
at  E  and  F  is  accounted  for  by  the  fact 
that  E  and  F  were  almost  directly  over  the 
poles  of  the  magnet  while  D  was  at  one 
side  and  the  penetration  was  much  greater 
at  E  and  F — again  proof  of  the  currents 
and  of  the  effect  of  the  magnet. 

I  have  also  produced  Magneto-graphs,  as 
I  have  chosen  to  call  them,  over  an  electro- 
magnet and  over  a  straight  wire  bearing  a 
current,  but  I  have  not  as  yet  secured 
clear  results,  owing  to  the  difficulty  of 
maintaining  a  steady  current  for  sufficient 
length  of  time. 


SOURCES   OF  ELECTRICITY. 

{Continued  from  page  12) 

As  might  be  suspected,  the  voltage  pro- 
duced by  heating  a  single  metallic  couple, 
such  as  the  above,  is  very  small,  and  where 
a  greater  potential  is  desired  a  large  num- 
ber of  similar  couples  are  mounted  in  as 
compact  a  manner  as  possible,  and  all  of 
the  junctions  are  heated  simultaneously 
by  gas  or  coal  as  shown  in  Fig.  6.  The 
difference  of  potential  for  a  bismuth-anti- 
mony couple  is  about  117  microvolts  for 
each  degree  Centigrade,  when  the  junction 
is  heated  above  the  rest  of  the  circuit.  The 
total  current  produced  by  the  massive  com- 
pound circular  thermopile  shown  in  Fig. 
6  is  80  volts  and  3  ampres,  which  is  suf- 
ficient to  light  a  number  of  incandescent 
lamps. 

Dynamic  Electricity :  The  most  success- 
ful and  practical  source  of  electrical  energy 
as  we  know  it  today  is  the  Dynamo.  One  of 
these  machines,  which  depends  upon  the 
cutting  of  magnetic  lines  of  force  by  a  ro- 
tating wire  or  inductor  as  it  is  called,  is 
shown  in  Fig.  7.  It  was  Faraday,  who  early 
in  the  19th  century  discovered  that  if  a 
circular  copper  disc  be  rotated  between 
the  poles  of  a  strong  steel  magnet  or  an 
electro-magnet,  that  there  would  be  a  cur- 
rent produced,  or  rather  induced  in  the 
moving  copper  disc,  due  to  the  cutting  of 
magnetic  lines  of  force.  The  current  was 
found  to  flow  from  the  shaft  supporting  the 
disc  to  the  rim,  or  vice  versa,  according  to 
the  direction  of  rotation.  This  current  was 
conducted  away  by  wires,  having  sliding 


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brush  contacts,  one  of  which  was  made  to 
bear  against  the  shaft,  while  the  other  made 
contact  with  the  edge  of  the  disc. 

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Electricity  from  Coal:  One  of  the 
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72 


THE  ELECTRICAL  EXPERIMENTER 


May,  1917 


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idize  to  C02,  which  mostly  bubbles  up  thru 
the  caustic  soda  solution  and  escapes.  This 
cell  gives  about  1  volt  E.M.F.  The  action 
occurring  in  the  production  of  electrical 
energy  is  believed  to  be  partly  voltaic  and 
thermo-electric.  The  cell  has  an  efficiency 
of  about  8  per  cent — compared  to  12  to  15 
per  cent  for  modern  steam  boiler  and  en- 
gine plants,  and  the  cost  of  raw  materials 
to  replenish  it  is  said  to  be  at  least  34  times 
that  for  a  good  steam  engine,  while  the 
residue  or  ash  from  such  a  battery  would 
possibly  weigh  12  times  that  from  a  corre- 
sponding steam  plant. 

Plant  Electricity  :  It  is  not  generally 
known  that  certain  plants  exhibit  pro- 
nounced electrical  activity,  but  such  is  the 
case.  Perhaps  the  strongest,  that  is  in  the 
sense  of  electrical  vibrations,  is  the  sensi- 
tive plant  (Mimosa  pudica),  shown  in  the 
illustration  (Fig.  9).  Others,  such  as  iris, 
nicotiana,  nasturtiums  and  practically  all 
the  meat-eating  plants,  such  as  the  "Venus 
fly-trap"  and  the  "sundew,"  afford  splen- 
did examples  for  experimentation.  If  any 
of  these  be  placed  "in  connection  with  a 
galvanometer  by  means  of  electrodes  at- 
tacht  to  leaves  on  different  sides,  and  one 
side  of  the  plant  be  exposed  to  sunlight 
while  the  other  side  is  kept  shaded,  then 
within  froui  three  to  ten  seconds  after  ex- 
posure to  sunlight  there  will  be  a  flow  of 
electricity  from  the  lighted  to  the  shaded 
parts  amounting  to  .005  to  .02  volt.  This 
continues  for  about  five  minutes,  when  the 
magnet  begins  to  swing  back  and  shows  an 
opposite  current  of  considerable  magnitude. 
The  manifestations  are  similar  to  those  of 
"teranized  nerve." 

A  better  understanding  of  the  electrical 
qualities  of  plants  will,  no  doubt,  explain 
many  of  the  hitherto  mysterious  habits  of 
meat-eating  plants.  Especially  will  this  be 
true  of  such  terrible  and  uncanny  plant 
monsters  as  the  "devil's  snare"  of  South 
America  and  the  mammoth  Utricularia,  or 
fishing  plant,  which  lures  minnows  and 
small  animals  into  its  voracious  mouth,  and 
suddenly,  as  if  an  electric  button  were  se- 
cretly prest,  closes  in  upon  its  helpless 
prey.  In  other  words,  it  fishes  with  a  net 
electrically  wired  !  Strange  as  it  may  soun A 
this  plant  safeguarded  itself  by  means  of 
its  electrical  currents  ages  before  we  used 
the  electric  burglar  alarm  and  door  bell. 
Were  it  not  for  this  protection,  the  plant 
could  not  live  and  hold  its  own  in  such  an 
aurial-infested  region  as  it  needs  for  its 
fishing  ground. 

Animal  Electricity  :  Altho  not  so  com- 
monly known,  there  are  in  the  world  several 
varieties  of  electric  fishes  and  eels  which 
possess  quite  remarkable  power.  Several 
species  of  these  creatures  inhabiting  the 
waters  of  certain  parts  of  the  earth  possess 
the  power  of  producing  more  or  less  pow- 
erful electric  discharges.  Physiologically, 
the  principal  creatures  of  this  class  are  the 
Torpedo,  the  Gymnotus  and  the  Silurus. 
One  of  the  most  powerful  electric  fishes  is 
the  Raia  Torpedo  or  Electric  Ray,  of  which 
there  are  three  species  inhabiting  the  Med- 
iterranean and  Atlantic.  This  particular 
specimen  is  provided  with  an  electric  or- 
gan on  the  back  of  its  head.  The  organ 
consists  of  laminae  composed  of  polygonal 
cells  to  the  number  of  eight  hundred  or  one 
thousand,  or  even  more,  which  is  supplied 
with  four  large  bundle  of  nerve  fibers.  The 
under  surface  of  this  fish  is  negative:  while 
the  upper  surface  is  positive.  With  the 
Gymnotus  or  Surinam  eel,  the  electric  or- 
gan extends  the  whole  length  of  the  body 
from  tail  to  head.  It  has  been  recorded  by 
Humboldt  that  a  lively  combat  ensued  be- 
tween a  number  of  electric  eels  and  a  herd 
of  wild  horses,  which  were  driven  by  the 
natives  unconsciously  into  the  swamps  in- 
habited by  the  Gymnotus.  This  particular 
specimen  of  electric  fish  is  said  to  be  able 


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May,  1917 


THE  ELECTRICAL  EXPERIMENTER 


73 


to  give  a  most  terrible  shock,  and  proves  a 
most  formidable  antagonist  when  it  has 
grown  to  its  full  length  of  five  to  six  feet. 
In  the  Silurus  shown  in  our  Fig.  10,  the 
electric  current  flows  from  head  to  tail. 

It  has  been  shown  by  several  scientists 
that  nerve  excitations  and  muscular  con- 
tractions of  human  beings  are  the  seat  of 
slight  electrical  currents.  For  one  thing 
it  has  been  shown  that  the  beating  of  the 
heart  really  creates  rhythmical  electro-mo- 
tive force. 

Photo- Electricity  :  One  of  the  most  in- 
teresting sources  of  electrical  energy  and 
also  one  of  the  most  direct  methods  of 
production  of  electro-motive  forces  is  found 
in  the  photo-electric  cell.  Simply  explained 
this  remarkable  device  comprises  nothing 
more  than  two  copper  plates,  one  of  which 
is  perforated  and  blackened  by  oxidizing 
in  a  gas  flame,  while  the  rear  or  second 
plate  is  polished,  and  both  of  which  plates 
are  placed  in  a  suitable  tank  containing  a 
salt-water  solution.  One  side  of  the  tank 
which  contains  the  copper  plates  is  fitted 
with  a  glass  window  and  when  sunlight, 
or  any  other  source  of  light,  is  allowed  to 
strike  the  cell,  there  is  a  difference  of  elec- 
tric-potential set  up  between  the  front  and 
rear  copper  plates.  This  particular  cell  as 
developed  by  Mr.  Theodore  W.  Case,  was 
described  extensively  in  an  article  which 
appeared  in  the  September,  1916,  number  of 
this  journal.  It  was  found  possible  with 
some  of  these  photo-electric  cells  to  obtain 
a  voltage  of  one-tenth  and  an  amperage  of 
two-tenths ;  the  cell  delivering  a  steady 
current  as  long  as  the  light  shown  on  it. 
It  is  of  course  possible  to  connect  a  large 
number  of  cells  in  series  or  parallel  to  ob- 
tain any  voltage  or  current  desired. 

Radium  Electricity  :  It  is  generally  con- 
ceded in  scientific  circles  that  the  activity 
possest  by  radium  is  fundamentally  electri- 
cal in  nature.  Radium  gives  off  three 
kinds  of  rays  known  as  the  alpha,  beta  and 
gamma  rays.  It  is  possible  to  influence  two 
of  these  rays  (alpha  and  beta  rays)  by 
means  of  a  magnet  or  an  electro-magnetic 
field,  which  indicates  that  they  are  un- 
doubtedly electrical  in  their  fundamental 
structure.  Another  experiment,  which  any 
schoolboy  can  readily  perform  with  a  piece 
of  radio-active  mineral,  is  as  follows :  First, 
an  electric  charge  is  produced  on  a  sensi- 
tive gold  leaf  electroscope,  so  that  the  leaves 
diverge;  then  grasp  a  piece  of  the  radio- 
active mineral  (some  may  be  so  fortunate 
as  to  possess  a  tube  containing  a  small 
quantity  of  radium  bromid)  and  bring  this 
into  proximity  with  the  metal  ball  or  disc 
at  the  top  of  a  charged  electroscope.  It 
will  be  noted  that  the  latter  loses  its  charge 
on  the  gold  leaves  almost  instantly;  the 
electronic  activity  of  the  radium  bromid  or 
other  radio-active  substance  used  creating 
a  change  in  the  electrical  field  about  the 
'electroscope,  apparently  making  it  more 
conductive,  so  that  the  bound  electric  charge 
on  the  gold  leaves  can  escape.  Those  in- 
terested in  the  subject  of  "Radium"  and 
the  many  electrical  and  other  effects  cre- 
ated by  the  greatest  mystery  of  the  scien- 
tific world  to-day  will  do  well  to  read  the 
extensive  article  on  this  subject,  which  ap- 
peared in  the  September,  1916,  number  of 
The  Electrical  Experimenter.. 


RADIO  ENGINEERS  DINE. 

The  Washington  section  of  the  Institute 
of  Radio  Engineers  gave  a  dinner,  March 
third,  at  the  Commercial  Club,  Washington, 
D.C.,  complimentary  to  Brigadier-general 
George  O.  Squier,  chairman  of  the  Wash- 
ington section.  The  following  named  gen- 
tlemen from  New  York  participated:  R.  A. 
Weagant,  chief  engineer,  and  David  Sar- 
noff,  commercial  manager,  of  the  Marconi 
Wireless  Telegraph  Co.,  of  America;  Maj- 
or J.  Andrew  White  and  W.  J.  Hernan,  of 
the  Wireless  Press. 


THE  IONIC  RADIO  SYSTEM  AND 
THEORY  OF  IONIC  TUNING. 

(Continued  from  page  31) 
detector  and  Weston  relay  are  here  con- 
nected in  multiple,  the  connections  from 
the  local  side  of  the  Weston  relay  being 
the  same  as  above  described. 

The  preferred  type  of  my  detector  used 
in  this  system  is  shown  in  Fig.  5,  and  com- 
prises large  nickel-plated  binding  posts  16 
and  17  mounted  about  two  inches  apart,  cen- 
ter to  center,  on  any  suitable  material  so 
as  to  support  the  electrodes  19  and  20.  To 
19  a  brass  rod  one  eighth  of  an  inch  in 
thickness,  is  fitted  a  crystal  of  silicon  21, 
cut  in  the  form  of  a  truncated  cone.  Its 
base  is  glued  to  the  rod,  the  electrical  con- 
nection being  made  by  wrapping  the  joint 
between  the  brass  rod  and  the  silicon  with 
tinfoil.  The  electrode  20  comprises  three 
inches  of  flexible  cord,  scraped  of  its  in- 
sulation, then  bent  double  and  tightly  twist- 
ed, the  loose  ends  being  cut  off  evently.  If 
the  end  of  the  silicon  can  be  ground  smooth 
without  destroying  its  sensitivity  a  polished 
brass  rod  may  be  used. 

This  makes  a  detector  costing  about  35 
cents  to  construct.  It  will  have  a  highly 
finished  appearance,  exceptional  reliability, 
unusual  sensitivity  and  require  very  little 
adjustment,  as  the  parts  are  fixed  perma- 
nently in  place.  Those  trying  this  form  of 
detector  resembling  the  early  "E.  I.  Co." 
Auto-coherer  I  am  sure  will  be  well  satis- 
fied. After  eleven  years  of  experimenting 
with  all  forms  of  commercial  detectors  1 
have  found  this  one  the  only  type  constant 
enough  for  quantitative  measurements. 

Having  described  one  set  of  apparatus 
adapted  to  be  operated  according  to  my  new 
method  of  tuning  I  will  now  briefly  describe 
the  characteristics  of  crystal  detectors  and 
the  theory  of  operation  of  both  thermo- 
electric and  ionic  detectors,  in  order  more 
clearly  to  disclose  the  exact  nature  of  my 
new  method. 

A  Thermo  Detector  consists  of  a  very 
fine  point  or  "cat-whisker"  resting  upon  a 
thermo  crystal  with  a  comparatively  light 
contact.  When  an  alternating  current 
passes  to  and  from  the  crystal,  heat  is  gen- 
erated in  minute  quantities  at  this  point. 
This  heat  causes  a  "thermo-pile  action"  and 
generates  a  thermo-electro-motive  force. 
Impulses  of  alternating  current  coming  in- 
to the  detector  in  such  direction  that  their 
direction  is  the  same  as  that  of  the  thermo 
e.m.f.  are  allowed  to  continue  and  pass  on 
thru  the  circuit.  Those  passing  in  the  op- 
posite direction  are  opposed  by  the  thermo 
e.m.f.  and  are  supprest  or  wiped  out.  The 
impulses  which  reach  our  'phones  then  are 
always  in  the  same  direction  as  the  thermo 
e.m.f.  Thus  is  accomplished  the  rectifica- 
tion by  thermo  crystal  detectors.  These 
crystals  always  require  a  metallic  point  and 
to  this  class  of  thermo  crystals  belong  the 
following:  copper  pyrites,  tellurium,  man- 
ganese dioxid,  chalco-pyrites,  galena,  iron 
pyrites,  etc. 

Ionic  detectors  are  also  rectifiers  but  per- 
form their  function  in  a  different  manner, 
these  metal  points  not  being  necessary  and 
the  form  of  contact  being  of  relatively  small 
importance.  These  detectors  have  no  use- 
ful thermo  e.m.f.  A  large  polished  plate  of 
the  crystal  may  be  placed  between  two  high- 
ly polished  electrodes  and  it  will  work  equal- 
ly well,  if  not  better,  than  with  a  point.  I 
have  taken  a  piece  of  molybdenite  one-half 
inch  in  length  and  tacked  it  to  a  board  with 
a  tack  at  each  end.  It  worked  very  well  as 
a  detector  and  required  no  adjustment.  It 
was  not  especially  sensitive  but  its  operation 
was_  perfectly  constant.  On  the  contrary 
an  ionic  detector  rectifies  by  the  polariza- 
tion of  its  contained  ions,  an  ion  being  a 
combination  of  a  number  of  positively 
charged  molecules,  with  one  negatively 
charged  electron. 


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THE  ELECTRICAL  EXPERIMENTER 


May,  1917 


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Let  the  pyramids  in  Fig.  4  represent  the 
ions  in  an  ionic  crystal,  the  bases  represent- 
ing the  molecules  and  the  vertices  or  points 
the  electrons.  The  electrons  or  points  being 
negatively  charged,  seek  what  is  to  be  the 
positive  pole  of  the  detector  for  the  recti- 
fied current.  The  molecules  being  positive- 
ly charged  seek  what  is  going  to  be  the 
negative  pole  of  the  detector.  When  an  al- 
ternating current  enters  the  crystal  these 
ions  are  polarized,  somewhat  as  the  mole- 
cules of  iron  in  an  iron  bar  are  polarized 
in  magnetic  hysteresis.  This  makes  the 
crystals  better  conductors  in  one  direction 
than  in  the  other,  or  in  other  words  they 
become  rectifiers.  The  impulses  passing 
thru  the  crystal  in  the  direction  of  the 
points  (Fig.  4)  meet  a  very  low  resistance 
and  are  allowed  to  continue.  The  impulses 
coming  in  the  opposite  direction,  or  against 
the  points,  meet  a  very  high  resistance  and 
are  converted  into  heat,  being  to  all  practi- 
cal purposes  thus  supprest  or  wiped  out. 
To  this  class  of  ionic  crystals  belong  the 
crystals  of  silicon,  molybdenite,  perikon 
(copper  pyrites  and  zincite),  carborundum 
and  titanium  dioxid,  titanium  (TiO..)  oc- 
curring in  two  forms,  viz.,  as  the  minerals 
brookite  and  anataste. 

Thus  while  both  the  thermo  and  ionic 
detectors  convert  alternating  current  into 
direct  current,  the  former  work  by  a  ther- 
mo e.m.f.  in  one  direction,  while  the  po- 
larized ions  of  the  latter  cause  these  crys- 
tals to  conduct  better  in  one  direction  than 
in  the  other. 

My  unique  method  of  ionic  tuning  de- 
pends upon  the  following  discovery,  which 
I  have  made,  viz.:  The  ions  of  each  chemi- 
cal element  or  compound  have  a  definite 
rate  of  vibration,  the  ionic  groups  of  no  two 
elements  or  compounds  having  the  same 
rate  of  vibration.  Thus  each  chemical  ele- 
ment or  compound  is  sharply  distinguished 
from  every  other  element  or  compound  by 
its  characteristic  ionic  vibrati-n  rate. 

My  novel  method  of  ionic  tuning  is  based 
on  this  newly  discovered  principle  and  I 
make  use  of  the  principle  in  the  following 
simple  manner — namely,  by  employing  the 
same  chemical  element  or  compound  in  re- 
ceiving the  radio  impulses  as  in  generating 
them.  For  example,  silicon  may  be  em- 
ployed both  in  the  spark  gap  at  the  send- 
ing station  and  in  the  detector  at  the  re- 
ceiving station;  or,  when  employing  a  zinc- 
ite detector  at  the  receiving  station,  a  zinc 
spark  gap  may  be  used  at  the  sending  sta- 
tion, and  I  have  found  that  not  only  can 
excellent  selectivity  be  obtained  in  this  man- 
ner, but  the  detector  is  far  more  sensitive 
to  a  sender  employing  the  same  material, 
thus  permitting  transmission  over  much 
greater  distances. 

This  phenomenon  I  believe  to  be  due  to 
the  fact  that  the  vibration  of  the  ions  in 
the  detector  is  vastly  more  easily  affected 
by  disturbances  of  the  same  basic  character 
produced  in  the  ether  by  a  sender  of  the 
same  material.  On  the  contrary,  when  dis- 
similar elements  are  used  in  the  sender  and 
receiver  respectively,  as  has  heretofore  been 
done  universally,  the  ionic  vibration  at  each 
end  is  not  in  unison  but  is  in  dissonance. 

In  further  experimentation  along  this  line 
I  intend  more  fully  to  study  the  effects  of 
combining  two  or  more  elements  in  both 
the  sender  and  transmitter  in  order  to  de- 
termine whether  or  not  any  material  loss  of 
efficiency  or  other  disadvantage  results  from 
such  combination,  and  I  suggest  this  as  one 
of  the  many  fruitful  fields  of  research 
opened  for  future  endeavor  by  my  discov- 
eries herein  publicly  disclosed  for  the  first 
time. 


It  is  stated  that  one  result  of  the  war  in 
Germany  has  been  the  greatly  extended  use 
of  aluminum  for  many  purposes.  Its  use 
is  one  of  the  outstanding  features  of  cap- 
tured  German   motor   construction,  being 


used  for  crank  cases,  gear  boxes  and  even 
cylinder  heads,  jackets  and  shafts.  The 
Germans  are  said  to  be  able  to  produce 
aluminum  very  cheaply,  largely  owing  to 
the  mining  of  coal  in  occupied  French  ter- 
ritory by  forced  labor.  The  cheap  produc- 
tion of  electricity  has  also  stimulated  the 
development  of  electric  motor  vehicles, 
which  are  now  being  run  with  nickel-iron 
batteries,  owing  to  the  shortage  of  lead. 

AN  ELECTRIC  PARADOX  OR  SE- 
LECTIVE LAMP  CONTROLLER. 

(Continued  from  page  37) 
mechanism.  Adjust  N  so  that  the  travel  of 
the  armature  shaft  is  such  that  every  time 
it  travels  from  the  down  to  the  up  position, 
a  tooth  of  the  ratchet  will  have  moved  the 
distance  between  two  teeth  (1/12  revolu- 
tion). 

The  three  lights  to  be  operated  and  also 
the  knife  switch  may  be  mounted  on  a  suit- 
able lamp  board  as  shown  in  the  photo- 
graph. The  mechanism  just  described  and 
also  the  rheostat  may  be  hidden,  and  only 
the  wires  coming  to  the  lamp  board  ex- 
posed. 

I-t  will  no  doubt  afford  the  reader  con- 
siderable amusement  when  he  shows  the 
device  to  some  of  his  friends  who  think 
they  are  wiring  sharks  and  that  nothing 
electrical  can  fool  them. 


A  STUDY  OF  THE  LAW  OF  RE- 
SPONSE OF  THE  SILICON 
DETECTOR. 

(Continued  from  page  34) 
ponents  of  the  transmitted  waves,  loops 
were  made  with  the  lengths  of  the  vertical 
and  horizontal  portions  of  the  wire  in  vary- 
ing ratios.  Curves  showing  extreme  varia- 
tions were  obtained.  The  conclusion  to  be 
drawn  from  these  curves  is  that  the  hori- 
zontal portions  of  the  loop  give  a  maxi- 
mum response  at  0  deg.  and  180  deg.,  the 
vertical  portions  at  45  deg.  and  135  deg. 
The  receiver  responds  both  to  the  horizontal 
and  vertical  components  of  the  waves  re- 
ceived, and  the  position  of  the  maxima 
will  vary  with  the  particular  form. 

Receiver  in  Horizontal  Plane. 

Since  for  the  study  of  the  law  of  the 
detector  it  was  desirable  to  eliminate  as 
far  as  possible  all  response  to  the  vertical 
component,  the  entire  receiver  was  placed 
in  the  horizontal  plane  and  suspended  as 
before  by  rubber  bands.  To  reduce  still 
further  the  response  without  the  resonator 
the  short  loop  which  had  given  the  mini- 
mum effect  was  used.  The  screen  was  ro- 
tated thru  360  deg.  and  readings  were  taken 
every  20  deg.  with  and  without  the  reso- 
nator as  before.  The  curves  obtained 
showed  the  effect  without  the  resonator  to 
be  a  much  smaller  fraction  of  the  entire 
response  than  under  the  best  conditions 
with  the  receiver  vertical.  As  a  further 
precaution,  oscillator,  receiver  and  rotat- 
ing screen  were  carefully  centered.  Curves 
obtained  under  these  conditions  both  with 
and  without  the  resonator  had  their  maxi- 
ma at  0  deg.  and  180  deg.,  and  their  mini- 
ma at  90  deg.  and  270  deg.,  and  the  effect 
without  the  resonator  was  extremely  small. 

The  effect  for  the  90  deg.  position  of  the 
rotating  screen,  the  position  of  no  trans- 
mission, was  still  to  be  considered.  This 
residual  effect  with  the  resonator  was  about 
15  per  cent,  of  the  maximum,  and  indicated 
that  with  the  screens  used  there  were  dif- 
fraction effects  which,  as  might  be  expected, 
were  more  noticeable  with  the  resonator 
than  without.  In  order  to  investigate  the 
diffraction  the  receiver  was  placed  in  a  tin 
box.  The  response  to  the  waves  did  not  en- 
tirely cease  until  the  tin  cover  was  made 
completely  to  enclose  the  receiver ;  even  a 
small  opening  in  the  cover  produced  a  de- 
cided deflection  of  the  galvanometer.  That 


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THE  ELECTRICAL  EXPERIMENTER 


75 


the  effect  was  due  to  the  action  of  diffrac- 
ted waves  on  the  receiver  was  further 
shown  by  the  fact  that  with  the  rotating 
screen  in  the  position  to  allow  no  transmis- 
sion a  wire  reflector  back  of  the  receiver  at 
varying  distances  clearly  indicated  the  pres- 
ence of  nodes  and  loops  at  distances  apart 
which  showed  the  wave-length  to  be  that 
of  the  original  wave.  The  average  distance 
from  node  to  node  was  found  to  be  slight- 
ly more  than  50  cm.,  making  the  wave- 
length approximately  100  cm. 

Final  observations  were  made  with  the 
receiver  in  the  horizontal  position  at  a  dis- 
tance of  225  cm.  from  the  fixt  screen,  and 
with  the  oscillator  at  distances  from  the 
screen  ranging  from  120  cm.  to  230  cm. 

The  Law  of  the  Silicon  Detector 

Since  for  the  final  curves  obtained  the 
''receiver  was  so  adjusted  as  to  respond  only 
•  to  the  horizontal  component  of  the  trans- 
mitted wave,  it  seemed  possible  to  use  the 
data  to  determine  the  law  of  response  of 
the  silicon  detector  with  a  variation  in  the 
intensity  of  the  incident  wave.  The  data 
already  obtained  showed  the  response  of 
the  receiver  for  each  position  of  the  rota- 
ting screen.  Since  only  the  component  of 
the  wave  at  right  angles  to  the  wires  of 
the  screen  could  be  transmitted,  the  am- 
plitude of  the  transmitted  wave  varied  as 
the  cosine  of  the  angle  between  the  wires 
and  the  vertical.  As  the  receiver  was  ca- 
pable of  responding  only  to  horizontal 
waves,  the  transmitted  component  suffered 
a  second  resolution  at  the  receiver,  which 
again  cut  down  its  amplitude  by  the  cosine 
of  the  same  angle.  Hence  the  amplitude 
of  the  component  of  the  wave  to  which  '  le 
receiver  responded  was  proportional  to  the 
square  of  the  cosine  of  the  angle  between 
the  vertical  and  the  wires  of  the  screen. 
Presumably  the  amplitude  of  the  oscilla- 
tions set  up  in  the  receiver  for  different 
positions  of  the  screen  was  proportional  to 
the  amplitude  of  this  received  component, 
and  hence  to  the  square  of  the  same  angle. 

In  determining  the  law  only  those  data 
were  considered  in  which  the  values  of  the 
current  obtained  without  the  resonator  were 
small.  For  each  set  of  readings  two  curves 
were  plotted,  with  the  galvanometer  de- 
flections as  abscissae  and  in  one  case  the 
second,  in  the  other  the  fourth  powers  of 
the  cosines  of  the  angles  as  ordinates. 

From  these  results  it  seems  safe  to  con- 
clude that  the  rectified  current  is  propor- 
tional to  the  fourth  power  of  the  cosine  of 
the  angle  between  the  vertical  and  the  wires 
of  the  rotating  screen. 

Since  the  amplitude  of  the  oscillations  in 
the  receiver  is  presumably  proportional  to 
the  square  of  the  cosine,  this  result  indi- 
cates that  the  rectified  current  thru  the 
silicon  detector  is  proportional  to  the  square 


of  the  oscillating  current  in  the  receiver. 
Austin,  in  his  study  of  the  silicon  detector, 
reached  the  conclusion  that  for  alternating 
currents  of  ordinary  frequencies  and  for 
oscillating  currents  of  a  frequency  of  140,- 


000  the  rectified  currents  are  approximately 
proportional  to  the  square  of  the  alternating 
currents.  The  results  of  the  investigation 
of  the  writers  confirm  this  law  for  a  fre- 
quency  of  approximately  3X10".  


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76 


THE  ELECTRICAL  EXPERIMENTER 


May,  1917 


STRONGER  WIRELESS 
COMMUNICATION. 

Another  record-breaking  achievement  in 
the  wireless  art  has  been  accomplished  by 
the  Marconi  system  in  establishing  strong, 
direct  and  continuous  communications  over 
twelve-hour  periods  between  the  station  of 
the  Marconi  Wireless  Telegraph  Company  of 


America  at  Chatham,  Mass.,  and  that  of  the 
English  Marconi  Company  at  Carnarvon, 
Wales.  The  signals  received  at  Chatham 
from  Carnarvon  were  from  three  to  eight 
times  as  strong  as  those  obtained  from  any 
other  "European  station.  These  tests  were 
successfully  carried  out  on  January  twen- 
ty-ninth and  thirtieth. 


A  SIMPLE  ELECTRIC  MOTOR  AT- 
TACHMENT FOR  PHONOGRAPHS. 

{Continued  from  page  40) , 

other  two  holes  mentioned  are  intended  to 
take  the  bolts  that  run  through  the  motor. 
These  bolts  are  lengthened,  by  the  addi- 
tion to  their  ends  of  Yi  inch  binding  posts, 
as  shown  in  Fig.  1,  upper  end  of  the  motor, 
or  are  replaced  by  new  bolts  long  enough 
to  extend  through  the  top  board,  so  as  to 
support  the  motor.  In  the  writer's  case 
it  was  a  simple  matter  to  find  two  short 
binding  posts  which  would  screw  on  to 
the  ends  of  the  motor  bolts.  With  these 
in  place  the  motor  shaft  was  inserted 
through  the  center  hole,  the  binding  post 
slipping  into  the  other  two  holes,  and  the 
thumb  bolts  which  fit  the  top  threads  of 
the  binding  posts,  were  fitted  with  soft 
rubber  washers,  inserted  in  place  and 
screwed  up  tight  to  hold  the  motor  in 
place.  The  rubber  washers  mentioned 
above  deaden  the  hum  of  the  motor  con- 
siderably, but  if  their  effect  is  not  great 
enough  two  thin  washers,  made  from 
banner  felt,  can  be  inserted  between  the 
motor  top  and  the  talking  machine  top, 
being  held  in  place  by  the  motor  bolts  and 
bearing  as  shown  in  Fig.  1  at  b. 

The  belt  should  be  crossed  in  order  to 
drive  the  turntable  properly ;  the  electric 
motor  having  its  field  winding  terminals 
reversed  if  it  rotates  in  the  wrong  direction. 

A  simple  white  string  belt,  about  1/20 
of  an  inch  in  diameter,  has  been  used  for 
about  two  months  with  excellent  results 
by  the  author,  although  at  first  several 
materials  were  tried  experimentally,  such 
as  leather,  rubber,  tape  and  laces.  Besides 
being  the  simplest  to  obtain  and  make  up 
the  string  belt  gave  the  best  service,  and 
is  still  in  use,  although  the  diameter  is 
reduced  about  30%  by  wear.  The  ends 
of  the  belt  were  simply  joined  by  being 
tied  in  an  ordinary  knot.  This  belt  is 
readily  renewed. 

When  the  driving  mechanism  has  been 
completely  assembled  one  end  of  a  flexible 
lamp  cord  can  be  attached  direct  to  the 
motor  wires,  after  first  being  passed 
through  the  hole  which  formerly  contained 
the  crank  handle,  for  winding  the  motor. 
The  lamp  cord  may  be  connected  to  a  lamp 
socket  and  the  motor  controlled  by  the 
key  switch  in  the  socket,  or  if  so  desired 
a  simple  push  button  switch  can  be  con- 
nected to  the  cord  near  the  machine,  or 
else  set  into  the  body  of  the  machine  itself. 
The  regular  stop,  with  which  the  phono- 
graph was  originally  fitted,  should  be  kept 
in  release  by  means  of  a  small  tack  or 
phonograph  needle  driven  into  the  machine 
top  to  hold  the  lever  at  starting  position. 

The  records  can  be  readily  changed 
without  stopping  the  machine,  provided 
the  turntable  is  not  held  back  too  much 
by  clumsy  manipulation  of  the  records. 
This  practice,  however,  is  not  to  be  espe- 
cially recommended,  and  is  not  at  all  neces- 
sary, as  the  machine  with  an  electric  motor 
attachment  attains  full  speed  very  quickly 
upon  starting.  The  speed  can  of  course 
be  regulated  in  the  manner  already  ad- 
vised, by  the  ordinary  speed  lever. 


WIRELESS  TELEGRAPHY. 

{Continued  from  page  27) 
Azores,  to  the  western  shores  of  Europe, 
to  Madeira,  Cape  Verde,  the  mouth  of  the 
Amazon,  Panama,  the  Galapagos  Islands 
off  the  western  coast  of  Ecuador,  and  Mag- 
dalena  Bay.  The  radius  also  embraces 
thru  the  chain  San  Francisco  and  the  whole 
stretch  of  the  California,  Washington  and 
Oregon  coasts,  the  lonely  wastes  of  Upper 
Canada,  Hudson's  Bay  and  the  southern 
nose  of  Greenland,  the  entire  Caribbean 
(Continued  on  page  78) 


OF  SLIGHTLY 
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Remember  the  books  are  damaged  but  in  many  cases  only  (he  bindings  have  a 
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THE  ELECTRICAL  EXPERIMENTER 


77 


Read  iki$Reiiiaikaltlf  Offei ! 


This  masterpiece  contains  160  pages,  400  illustrations.  Size 
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^Electrical  m 
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78 


THE  ELECTRICAL  EXPERIMENTER 


May,  1917 


Sea,  all  of  the  West  Indies,  most  of  Peru, 
all  of  Colombia,  Venezuela,  the  three  Gui- 
anas  and  the  watershed  of  the  Amazon; 
and  all  of  the  United  States,  Mexico  and 
the  Central  American  Republics  are  with- 
in the  range  of  these  stations.  Weather 
reports  and  time  signals  and  also  informa- 
tion in  regard  to  ice,  obstructions  to  navi- 
gation, etc.,  are  sent  out  broadcast  for  the 
information  of  navigators. 
The  success  of  Marconi  in  effecting  trans- 


oceanic communication  was  a  startling 
achievement.  Regular  message  traffic  has 
been  transmitted  between  Europe  and 
America  continually  for  more  than  eight 
years  over  a  duplex  wireless  circuit  be- 
tween Clifden  and  Glace  Bay;  that  is  to 
say,  messages  between  these  points  are 
transmitted  in  either  direction  simultane- 
ously. The  transmitting  and  receiving  ap- 
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yon  can  ill  afford  to  be  without  these  two 
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the  one  concern  in  America,  that  knows 
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concentrated  the  most  important,  up-to- 
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season.  Size  of  each  book  is  5x7  inches, 
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them. 


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EXPERIMENTAL  CHKMTSTRY. 

{Continued  from  page  52) 

base,  the  metal  of  the  base  enters  into  the 
acid  in  place  of  the  hydrogen  and  the  hy- 
drogen combines  with  the  hydrogen  and 
oxygen  of  the  base  to  form  water. 

HNO3  +    KOH    =    KNO3  +  K2O 

Nitric  Acid    Potassium    Potassium  Water 
Hydroxid  Nitrat 

H2SO4  +  2NaOH  =  Na2S04  +  2H2O 
Sulphuric     Sodium      Sodium  Water 
Acid       Hydroxid      Sulpha  t 

NOMENCLATURE  OF  SALTS— 

The  name  of  the  salts  containing  oxy- 
gen are  derived  from  the  name  of  the 
corresponding  acid.  The  characteristic 
suffix  of  the  acid  is  changed  to  indicate 
this  relation.  Thus,  the  suffix  ic  becomes 
ate,  and  the  suffix  -ous,  becomes  -ite. 

_  [Note:  The  final  "e"  is  usually  dropt  in 
simplified  spelling  as  used  in  this  journal.] 

Sulfuric  acid  form  Sulfate 
SulfuroMj  acid  form  SulHtes 
Nitric  acid  form  Nitrate 
Nitrous  acid  form  Nitrite 
Chloric  acid  form  Chlorate 
Hypochloremic  acid  form  Hypochlorite 
Permanganic  acid  form  Permanganate 

The  name  of  the  replacing  metal  is  re- 
tained, as,  Potassium  chlorat,  sodium  sul- 
phat,  calcium  hypochlorit,  potassium  per- 
manganat.  Notice  that  the  prefixes  Hypo- 
and  Per-  are  not  changed. 

The  names  of  salts  containing  only  two 
elements,  following  the  general  rule  for 
binary  compounds,  end  in  ide.  This  suffix 
is  added  to  a  modification  of  the  name  of 
the  non-metal,  giving  the  names  chlorid,. 
bromid,  sulphid,  fluorid,  etc.  The  prefix 
Hydro-  which  is  contained  in  the  name  of 
the  acid  is  omitted.  Thus,  the  name  of 
the  sodium  salt  of  hydrochloric  acid  is 
sodium  chlorid;  similarly,  there  are  the 
names  potassium  chlorid,  calcium  fluorid, 
and  sodium  iodid.  Sometimes,  the  salts  of 
these  hydrogen  acids  are  called  Halids,  to 
emphasize  their  relation  to  common  salt, 
which  in  Greek  is  called  Hals. 


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May,  1917 


THE  ELECTRICAL  EXPERIMENTER 


79 


Scientific  Exchange  Columns 


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OVER  75,000  PEOPLE  READ  THIS  JOURNAL 


3 


FOR  SALE — As  am  not  permitted  to  erect 
aerial  will  sell  my  new  cabinet  receiving  set. 
Contains  large  loose  coupler,  primary  and  secon- 
dary loads,  variable  and  fixt  variable  condensers, 
detector,  potentiometer,  buzzer  test  anchor  gap. 
All  instruments  enclosed,  with  switch  and  lever 
control.  With  Brandes  headset  $50.  Send  5c. 
stamp  for  photo.'  Also  spiral  helix  $2.  Spark 
Coil  $1.50,  tuner  14  inches  long  $1.  Switches, 
detector  parts,  several  lbs.  fine  wire  and  wireless 
books.  Wanted,  for  cash,  catboat  or  rifle.  Len  K. 
Wright,  518  East  83d  St.,  N.Y.  City.  

FOR  SALE—  M  K.W.  Closed-core  Transformer, 
$8.50.  Also  200  W.  Step-Down  Transformer  with 
6,  12,  18,  24  V.  taps,  $3.  Both  in  first-class  con- 
dition. F.  K.  Billau,  525  N.  Delaware,  Indian- 
apolis, Tnd.  __ 

FOR  SALE  —  International  Correspondence 
Schools'  course  in  arithmetic.  Also  wireless  ap- 
paratus, cheap.     Alex.  Serna,  Lehigh,  Okla.  

ATTENTION— Sale  or  Exchange:  Motor,  $20; 
lathe,  $35;  generator,  $6;  motor,  $6.  Stamp  for 
descriptions.    H.  E.  Neefe,  La  Farge,  Wis. 

EXCHANGE — Five  volume  set  of  Automobile 
Cyclopaedia,  red  cloth  bound,  gold  stamped,  also 
six  volume  set  of  Modern  Shop  Practice,  flexible 
leather  binding  (published  by  American  Technical 
Society),  current  editions,  for  receiving  or  sending 
apparatus  of  standard  make.  Charles  B.  Hayward, 
Great  Neck  Sta.,  New  York. 

IF  ANY  ONE  can  give  me  the  address  of  W.  B. 
Dougherty  it  will  be  thankfully  received.  Chas. 
Dougherty,  Louisiana,  Mo. 

WANTED — Coil  rated  at  2  inches.  Will  pay 
cash.  Henry  Kienzle,  501  East  84th  St.,  New 
York.  

FOR  SALE  OR  EXCHANGE— 1  5,000  M.  Loose 
Coupler,  $10,  also  small  Loose  Coupler,  $4,  or  will 
exchange  for  Variometer  or  Audion.  Wanted  to 
buy  good  polarized  relay.  Write  to  J.  Cingature, 
866  Thirteenth  nve.,  Milwaukee,  Wis. 

FOR  SALE — $5,  22  revolver  shot  six  times,  $3; 
loading  coil,  $1;  automatic  telephone,  $3;  $6.50 
moving  picture  machine,  $4.  William  D.  Peteet, 
Greenwood,  Miss. 

EXCHANGE— Good  mandolin  with  case,  for 
typewriter.  Write  if  interested.  Wm.  Bolme,  En- 
loe.  N.Pak.  _____ 

SALE — Telegraph  Instruments,  Motors,  etc. 
See  ad  in  April  Experimenter.  Sydney  Young, 
Jr.,  Addison,  N.Y..  R.F.D.  No.  4.  

FOR  SALE— Three-inch  coil,  $9;  relay,  $3; 
medical  coil  outfit  with  meter,  cost  $100,  sell  for 
$16.  Ford  electric  starter  and  generator,  $20 
Gorham  Cottrell.  1628  Jersey,  Ouincy,  111. 

FOR  SALE  OR  EXCHANGE— Railroad  motor 
car  for  electrical  goods.  S.  R.  Kimball,  Diamond 
Bluff,  Wis.  

BARGAIN — Rotary  gap  having  Klitzen  disc  and 
110-volt  Universal  motor,  $6.  Fred  Ancona,  16th 
St.,  &  Mineral  Spring  Road,  Reading.  Pa. 

FOR  SALE— 1,500  meter  tuning  coil;  1,000 
meter  tuning  coil;  detector,  60c.  All  new,  make 
offer.  Francis  H.  Coleman,  27  Salem  St.,  Spring- 
field,  Mass.  

4-Step  Packard  Transformer  in  paraffine  wax 
and  oak  case,  E.  I.  Government  phones,  5  lbs. 
No.  22  D.S.C.  wire.  Cheap.  Best  offer  takes  them. 
F.  Allen,  Bliss,  Takoma,  D.C.  

FOR  SALE — Two  brand  new  DeForest  ampli- 
fiers with  burned  out  bulbs.  Price  right.  Palmer 
Southworth,  34  Montowese  Street,  Hartford.  Conn. 

FOR  SALE — 200  watt  transformer.  Steps  110 
to  10,  20,  30  or  40  volts,  $10;  40  watt  dynamo  or 
1/12  H.P.  motor,  $7;  Inch  spark  coil;  fine  fat 
spark,  $4;  Testing  magneto,  $2.50;  20  ohm  sensi- 
tive pony  relay,  $1.50;  20  ohm  giant  sounder  and 
steel  key,  $2.50;  Portable  voltmeter,  1-20  range, 
$1.50;  Filings  coherer,  $1;  75  ohm  wireless  re- 
ceiver with  headband,  $1.25;  1/12  HP  water 
motor.  $1.50.    C.  M.  Adams,  Milford,  Ohio. 

SELL — 40  1  esson  Taxidermy  Course,  $9.  Trade 
3  yrs.  Youth's  Companions  for  Al,  2  slide  tuner. 
William  Litwiller.  Hopedale,  111. 


FOR  SALE— 110  volt,  l'/S  ampere  dynamo  ($12) 
used  very  little.    J.  T.  Greene,  Carrs,  Ga.  

FOR  SALE— Hytone  Clapp-Eastham  V2  kilowatt 
transformer  in  original  case.  No  helix,  gap,  or 
condenser.  Bargain,  $15.  Perfect  condition.  Also 
new  rotary  gap.  Never  used.  Adams  Morgan 
make,  Robbins  &  Myers  110  V  direct  current 
motor  speed  3,000.  This  gap  will  be  just  the  thing 
for  the  Hytone  transformer,  $8.  Both  for  $21. 
All  letters  answered.  Ralph  B.  Austrian,  49  St. 
Nicholas  Terrace,  New  York  City. 

EXCHANGE — "Remy"  magneto  with  vibrator 
and  1  inch  coil  without  vibrator  for  3,000  ohm 
Phones  or  what  have  you?  Walter  Heinrich,  15 
Colby  St.,  Lawrence,  Mass. 

FOR  SALE — Extremely  sensitive  Audio-Tron 
bulb,  $4.  Send  for  list  of  wireless  goods.  What 
have  you  for  sale?  Henry  Lehmberg.  5116  N. 
12th  St.,  Philadelphia.  

WANTED — Burnt  out  De  Forest  Audion  Bulbs. 
Will  pay  cash  or  exchange  wireless  goods.  Joe 
Singer,  Goldfield.  Nevada. 

FOR  SALE — Tigerman  Detecto-Amplifier  Type 
C,  panel  type  with  two  bulbs,  $16.  Eddie  Smith, 
688  South  39th  St..  Louisville.  Ky.  ■  

FOR  SALE — Thor  motorcycle,  good  running 
order,  has  up-to-date  equipment.  Bargain  at  $35. 
Also  Thor  motorcycle  complete  except  for  engine 
at  $10.     Harvey  Adams,  Chambershurg,  111.  

WANTED— R.J.  9  Audion  and  storage  battery, 
43  plate  variable  and  E.I.  or  Murdock  loader. 
L.  H.  Hammond,  Box  51,  Baden,  N.C. 

plllllllllllllllllllllllUlilllllllllllllllllllip 

I    TALK  ABOUT  RESULTS!  I 

m  17  PRYER  LANE,  g 

=  Larchmont  Manor,  N.Y.  = 

g  The  Experimenter  Pub.  Co., 

=  New  York  City  m 

{§  Dear  Sir:—  : 

g  Talk  about  results!  You've  got  to  {§{ 

§§  give  it  to  the  "E.  E."to  reach  the  B 

{§  right  people.    On  the  day  after  "  E.  |j 

§j  E."  came  out  I  received'a  reply  and  S 

H  they  have  been  coming  in  at  the  rate  I 

jj|  ofoneaday.  If Ieverhaveanything  H 

!  else  that  I  want  to  sell  I  will  send  pj 

H  my  "  ad  "  to  vou  every  time. 

H  Yours  truly,  = 

B  Clarence  de  Witt  Rogers,  Jr.  B 

IlillllllllllllllllllllllllllllllllllllllllillllllllllllllllWIIII 


NEW  $18.  Multi-Audi-Fone,  $12.  Mesco,  $12. 
Intensifying  Coil,  $7.50.  $15  Army  binoculars 
in  leather  case,  $9.  All  perfect.  Peter  Pinkston, 
Valdosta,  Ga. 

FOR  SALE— Pocket  Wireless  Set  3,000  meters, 
$2.75;  Redhead  single  head  set,  $1.85.  Max  Vin- 
eski,  Troy,  Pa. 

EXCHANGE  for  $16— One  Smith  Premier  No.  4 
typewriter,  excellent  condition,  used  only  short 
time.  Fred  Fries,  60  E.  Bringhurst  St.,  German- 
town,  Philadelphia,  Pa. 

FOR  SALE  OR  EXCHANGE — 1 54  H.P.  Gaso- 
line  Engine  nearly  new,  $20.  Wanted,  */2  H.P. 
Gasoline  engine.  Must  be  in  good  condition. 
Glenn  Johnson,  Missouri  Valley,  Iowa. 

TO  EXCHANGE — Chemical  laboratory,  value 
$15  for  wireless  instruments.  J.  Y.  Parsons,  1906 
Park  St.,  Kansas  City,  Mo.  

FOR  SALE— Cash  only,  almost  new,  half  K.W. 
Blitzen  transformer  mounted  in  mahogany,  worth 
$24  at  $15.  Also  R.J.  9  Audion  new  bulb,  $12. 
New  Audio-Tron  Panel,  two  filament.  $9.50.  Also 
one  K.W.  transformer,  new,  at  a  bargain.  All 
these  instruments  good  as  new.  Holtzer-Cabot 
phones,  new,  $7.  Don  D.  Tullis.  59  N.  Second 
St..  Newark-,  Ohio.  

FOR  SALE— 10  vols.  Hawkins'  Electrical  Guides 
and  one  vol.  Rogers'  Mechanical  Drawing.  Cost 
$12,  sell  for  $7.50.    M.  Jacobson,  Parksville,  N.Y. 


FOR  SALE  OR  EXCHANGE— Crookes  Spin 
thariscope,  $8;  Thomson  A.C.  voltmeter,  0-175. 
$4,  A.C.  Ammeter,  0-100,  $4.  Tuning  cabinet  hard 
rubber  panel,  variometer  coupling,  no  variables, 
neat,  compact  and  efficient,  $12.  Home-made 
transformer  coil,  about  300  watts,  $4.  Wanted, 
small  lathe,  oscilaudion,  variables,  books  or  tools. 
Experimenter,  2808  N.  Lawrence  St.,  Philadel- 
phia, Pa. 

WANT  TO  EXCHANGE  lenses,  camera  and 
electrical  measuring  instrument,  etc.,  for  old  coin 
and  stamps.  James  Christie,  107  Vanderbilt  Ave., 
Brooklyn.  N.Y.  

FOR  SALE — Tubular  Sending  Condenser;  po- 
tentiometer; water  motor;  large  tuning  coil;  box 
of  wire;  screws,  etc.;  one  ten  plate  sliding  con- 
denser, etc.  All  for  $5,  as  I  have  no  more  use 
for  same.  Write  or  call  evenings,  Henry  A.  Gil- 
man,  156  Jerome  St.,  Brooklyn,  N.Y. 

FOR  SALE  OR  EXCHANGE— Brandes  Navy 
Phones,  $9.25;  regenerative  coupler,  $6;  Clapp- 
Eastham  .002mf  variable,  $5.75;  Murdock  43 
plate  variable,  $3.10;  Murdock  wave  meter,  $5; 
Bunnell  key,  75c;  Standard  gap,  $1;  Murdock  ro- 
tary gap  in  sound  proof  mahogany  case — cost  $20 
and  is  brand  new,  $11.50;  5  K.W.  Aerial  switch, 
$5;  Amplifying  coil,  $5;  5  K.W.  Oscillation  trans- 
former, $10;  2  sections  Murdock  Moulded  Con- 
denser, $3;  600  feet  No.  12  copper  aerial  wire. 
$4.75;  8  Ball  Insulators,  $1;  two  10^2  inch  insu- 
lators, 75c;  Lightning  switch,  $1.25;  two  15  foot 
poles,  $5;  two  spreaders,  $2;  Winchester  model 
1906  repeating  .22,  $8;  Surgeon's  dissecting  in- 
struments, $7.50;  L.  C.  Smith  typewriter,  cost 
$97.50,  $45.  H.  W.  Semmelmeyer,  2629  N.  Fair- 
field Ave.,  Chicago.  111. 

SACRIFICE — Smith  motor  wheel,  $35.  Particu- 
lars on  request.  Best  condition.  Francis  Pray, 
102  Heath  St.,  Winter  Hill,  Mass.  

WILL  EXCHANGE  a  Keystone  milli-ampere 
meter  excellent  for  radio  measurements,  a  Gov- 
ernment type  Perikon  detector,  finely  finished. 
Want  small  110  volt  A.C.  motor,  rotary  variable 
condenser,  A.C.  voltmeter  or  ammeter,  or  what 
have  you?  Samuel  Cohen,  1936  Pitkin  Ave., 
Brooklyn,  NVY.  

POWERFUL  Waite-Bartlett  Static  Machine. 
8  rotary,  8  stationary  plates.  Gives  heavy  16-inch 
condenser  charge.  Excellent  for  X-rays  and  ex- 
periment; perfect  condition  and  best  workmanship: 
complete.  Cost  over  $300.  $75  or  best  offer  in 
wireless.  Photos  and  details  upon  request.  T. 
Earl,  Niles,  Mich. 

FOR  SALE — Mandolin,  good  as  new,  cost  $15. 
Will  sell  for  $10  cash.  Instruction  books,  music 
rack,  case  included.  Joseph  Dushek,  Post  Office 
Box  No.  114.     Owatonna.  Minn.  

INDIAN  TWIN  just  overhauled,  $70;  or  trade 
for  marine  engine,  6-15  H.P.  H.  Griffin,  Hart- 
selle,  Ala. 

HAVE— Oliver  Typewriter,  Model  3.  Want 
cash  or  receiving  apparatus.  Make  offer.  All  let- 
ters answered.  Herbert  Richter,  Collegeville, 
Minn. 

BARGAIN — Complete  new  Blitzen  Receiving 
set  with  extra  equipment.  Holtzer-Cabot  Phone?. 
In  perfect  condition.  Write  for  particulars.  Chas. 
Bayliss,  68  Peterboro  St..  Detroit.  Mich. 

FOR  SALE — Complete  Audio-Tron  on  panel 
with  all  controls  and  4-40  storage  battery.  Panel 
has  2  D.P.D.T.  mineral  change-over  switches 
wired  on.  Used  10  hours.  $10.  Also  "Arlington" 
4,000  M.  Coupler,  cost  $9,  for  $6.60  and  $4. 
Murdock  Oscillation  for  $3.  George  R.  Ham- 
mond. Oelwein,  Iowa. 

WILL  EXCHANGE  my  Twin-Cylinder,  6  H.P. 
Merkle  motorcycle,  in  perfect  condition,  for  good 
wireless  apparatus.  Francis  Joannini,  3326  17th 
St.,  Washington.  D.C. 

FOR  SALE— Set  Cyclopedia  of  Applied  Elec- 
tricity. Send  for  description.  All  letters  an- 
swered. J.  N.  Boyington,  South  Galena  Ave., 
Freeport,  111. 


You  benefit  by  mentioning  "The  Electrical  Experimenter"  when  writing  to  advertisers. 


8o 


THE  ELECTRICAL  EXPERIMENTER 


May,  1917 


FOR  SALE — Steam  engine  designed  for  com- 
mercial use.  Bore  seven-eighths,  stroke  2  inches; 
and  Hoyt  voltameter,  both  cheap;  $6  cash.  A  bar- 
gain.    John  N.  Lint,  Box  171,  Meyersdale,  Pa. 

FOR  SALE— Almost  new  Vz  K.W.  Blitzen  un- 
mounted transformer,  record  of  this  transformer 
is  300  miles.  10  volumes  "Hawkins  Electrical 
Guides"  good  as  new.  Write,  Hansford  Penning- 
ton, 1505  Wyoming  St.,  San  Antonio,  Texas. 

QUICK— Type  S  S  Motor,  $4;  2  slide  tuner, 
loading  coil,  condenser,  2  detectors,  $6.  All  new, 
perfect  condition.  Send  stamp  or  list.  All  an- 
swered.   Chester  Shurr,  Berthold,  N.D. 

FOR  SALE  OR  EXCHANGE— One  15,000 
meter  coupler,  one  receiving  set,  one  4'/2  H.P. 
gasoline  engine.  Wanted  Omnigraph  or  what  have 
you?    F.  B.  Dadisman,  Independence,  W.Va. 


FOR  SALE— One  Electro  Selenium  Cell,  $3.50. 
Two-inch  Bulldog  Spark  coil,  $4.50.  Gernsback 
Interrupter,  $1.75.  Electro  vario-selective  coupler, 
$4.50.  Electro  Amateur  phones  2,000  ohms,  $3. 
Electro  rotary  variable  condenser,  $1.75.  Electro 
fixt  variable  condenser,  75c.  Crystaloi  Detector, 
$2.25.  ■  Two  Electro  high  voltage  condensers,  $1. 
Knapp  Type  S  S  Dynamo  Motor,  $3.  Stromberg 
Transmitters,  new,  75c.  Telephone  Induction 
Coils,  50c.  New  receiver  cords,  3  ft.,  15c,  6  ft., 
25c.  All  these  articles  are  new  and  guaranteed. 
Prepaid.  Will  trade  for  Smith  Premier  Type- 
writer No.  2.    F.  A.  Steinbrook,  Brookville,  Pa. 


TRADE — }4  h.p.  133  or.  125  cycle  A.C.  Motor 
for  Audion,  Audiotron,  or  Transmitting  Appara- 
tus. H.  C.  Ross,  1087  Schiller  St.,  Columbus, 
Ohio. 


BARGAINS— Crocker-Wheeler  8  V.  1600 
R.P.M.  motor,  $2.  Rebuilt  6  V.  Storage  Battery, 
$6.  Inch  Spark  Coil,  $2.50.  Many  other  bar- 
gains. Write  for  specifications.  H.  R.  Huth, 
Beaver  Dam,  Wis. 

WANTED — Two  kerosene  or  gasoline  engines, 
one  horse-power,  second-hand,  good  order. 
Branchaud  Bros..  Rutland,  Vt.  

V2  H.P.  GASOLINE  ENGINE,  2000  ohm  Red 
Head  Phones  (new),  500  ft.  Aerial  Wire,  Coils 
of  Variometers,  Loose  Couplers,  etc.,  Detectors, 
Condensers,  4  lbs.  Wire,  Binding  Posts,  Switch- 
es, Knobs,  Buzzers,  Miniature  Lights,  Sockets, 
Pump  Gun,  etc.  First  money  order  for  $15  takes 
all.    E.  Myers,  499  So.  21st  St.,  Irvington,  N.J. 

EXCHANGE— New  Telephone  goods,  large  Mec- 
cano, gun.  Want  wireless  goods,  banjo  or  re- 
volver.    Towns,   Marlboro  St.,   Keene,  N.H. 


Opportunity  Exchange 


VOU  will  probably  find  more  opportunities  and  real  bargains  in  these  columns  than  anywhere  else  in  the  country.  Most  good  things  in 
A  life  are  hard  to  find  and  worth  going  after — these  little  ads  illustrate  that  point;  you  alone  will  be  the  real  loser  if  you  don't  take  the 
time  to  scan  through  these  columns. 

Advertisements  in  this  section  4c.  a  word  for  each  insertion.    Count  7  words  per  line. 

Name  and  address  must  be  included  at  the  above  rate.  Cash  should  accompany  all  classified  advertisements  unless  placed  by  an  ac- 
credited advertising  agency. 

Ten  per  cent,  discount  for  6  issues,  20  per  cent,  discount  for  12  issues  from  above  rate.    Objectionable  or  misleading  advertisements  not 

accepted. 

Advertisements  for  the  June  issue  should  reach  us  not  later  than  April  25. 

OVER  75,000  PEOPLE  READ  THIS  JOURNAL 

EXPERIMENTER  PUBLISHING  CO.,  INC.,  233  Fulton  Street.  New  York,  N.Y. 


j 


BOOKS 

TO  GET  BETTER  PICTURES:  Read  the 
Amateur  Photographer's  Weekly;  illustrated; 
weekly  prize  competitions;  print  criticisms;  many 
unique  features;  $1.50  per  year;  three  months' 
trial  subscription  25c;  Abel  Publishing  Company, 
401  Caxton  Bldg.,  Cleveland.  Ohio.  

HUNTING  AND  FISHING  GUIDE— Most 
complete  work  on  the  subject  printed.  Handy 
volume  for  all  sportsmen.  Postpaid  for  only  25c. 
Iona  Press,  Box  103,  Oak  Park.  111.  

STUDY  SALESMANSHIP  AT  HOME— Ex- 
pert course.  Copyrighted.  15  lessons  complete, 
$1.    Central  Company,  599  Ninth  Ave.,  New  York. 

DO  YOU  WANT  back  numbers  of  The  Elec- 
trical  Experimenter;'  Send  for  bound  volume 
No.  3,  containing  issues  from  May,  1915,  to  April, 
1916.  Price  $1.25.  Postage  on  7  lbs.  is  extra. 
Experimenter  Pub.  Co.,  233  Fulton  St.,  New  York 
City.  

BOOKS — Scientific  and  wireless  supplied.  Let 
us  know  what  you  want  and  we  will  quote  you. 
Experimenter  Pub.  Co.,  233  Fulton  St.,  New 
York  City.  

A  BINDER  for  The  Electrical  Experimenter 
will  preserve  your  copies  for  all  time.  Price  50c. 
Postage  on  3  lbs.  is  extra.  Send  for  one  to-day. 
Experimenter  Pub.  Co.,  233  Fulton  St.,  New 
York  City.  ^^^^^^^^^^^^ 

HELP  WANTED 

MEN  AND  WOMEN,  18  or  over,  WANTED 
for  U.S.  Government  Life  Jobs.  $75  to  $t50 
month.  Steady  work.  Short  hours.  Rapid  (ad- 
vancement. Common  education  sufficient.  Write 
immediately  for  free  list  of  positions  now  easily 
obtainable.  Franklin  Institute,  Dep't  B  2*7, 
Rochester,  N.Y. 

MISCELLANEOUS 

ELECTRICIANS— Send  50c.  for  10  Blue 
Prints  of  Motor  and  Generator  Connections.  28 
for  $1,  10  A.C,  4  D.C.  Motor  Winding  Diagrams 
for  $1  or  20  A.C,  4  D.C.  and  4  Rotary  Converter 
Drawings,  $1.60.  Winding  made  easy.  Martin 
Electric  Co.,  329  Irvington  PI.,  Denver,  Colo. 

COLLECT  AND  SELL  names  and  addresses  in 
your  spare  time.  Big  income.  No  canvassing. 
Detailed   instructions,   10c    (coin).    National  Ex- 

change,  1314  Park  Ave.,  New  York.  

EVERYBODY  WANTS  IT— Folding  pocket 
Coat  and  Hat  Holder.  Can  attach  anywhere  and 
remove  instantly,  nickel-plated.  Sample  10c.  Big 
seller  for  agents.     Wedge  Mfg.  Co.,  "Km'-'  Bing- 

hamton,  N.Y.   

STAMPS — 75.  all  different,  free.  Postage  2c. 
Mention  paper.    Quaker  Stamp  Co..  Toledo.  Ohio. 

250  Letterheads,  Envelopes  or  Radiogram 
blanks,  $1.50,  prepaid.     Record,  Media,  111. 

DO  YOU  WANT  to  buy.  sell  or  exchange? 
Send  5c.  for  the  Busy-Bee  Exchange,  also  list  of 
things  you  have  to  sell  or  exchange.  Busy-Bee, 

174  Plymouth  St..  New  Haven,  Conn.  

AGENTS — 500%  profit  putting  initials  on  auto- 
mobiles. Particulars  sent  free.  Address,  Auto 
Monogram  Co.,  2025  E.  Monmouth  St.,  Philadel- 
phia. Pa 


etc.,  25c  Satisfaction  guaranteed.  Circular 
free.  Associated  Phonograph  Co.,  Dept.  E.  Cin- 
cinatti. 


PHONOGRAPHS 

BLTILD  YOUR  OWN  PHONOGRAPH  or  man- 
ufacture them  for  profit.     Drawings,  instructions, 


PATENT  ATTORNEYS 

IDEAS  WANTED— Manufacturers  are  writing 
for  patents  procured  through  me.  Four  books  with 
list  of  hundreds  of  inventions  wanted  sent  free. 
I  help  you  market  your  invention.  Advice  Free. 
R.  B.  Owen,  130  Owen  Bldg.,  Washington,  D.C. 


PATENTS— R.  Morgan  Elliott  ,&  Co.,  Patent  At- 
torneys, Mechanical,  Electrical  and  Chemical  ex- 
perts, 716-724  Woodward  Bldg.,  Washington,  D.C. 


PATENTS — Without  advance  attorney's  fees. 
Not  due  until  patent  allowed.  Send  sketch  for 
free  report.  Books  free.  Frank  Fuller,  Wash- 
ington, D.C. 


PATENTS  ON  EASY  PAYMENTS.  Send 
model  or  sketch  for  Free  Search  and  Certified 
Registration  of  Your  Invention  for  your  Protec- 
tion. Free  Book  tells  what  to  Invent  and  How  to 
Obtain  a  Patent  on  Easy  Payments.  C.  C.  Hines 
&  Co.,  593  Loan  &  Trust  Bldg.,  Washington.  D  C. 


PHOTOGRAPHY 

AMATEUR  PHOTOGRAPHERS— Send  for 
our  catalog  on  photo  supplies.  We  retail  to  you 
at  wholesale  prices.  Films  developed,  8c.  Cort- 
land Merchandise  Co.,  Dept.  E.,  1851  N.  Kil- 
dare  Ave.,  Chicago,  111. 


MARCONI — We  have  a  limited  number  of  pic- 
tures of  Guglielmo  Marconi,  Nikola  Tesla,  and 
Dr.  Lee  DeForest  that  are  done  in  sepia  on  fine 
India  paper.  Fine  for  decorating  your  wireless 
room.  10c.  each  postpaid.  Experimenter  Pub- 
lishing Co..  233  Fulton  St.,  New  York  City. 


WIRELESS 

ELECTRIC  MOTORS  at  unusual  low  prices. 
1/6  H  P.,  $6;  Vt  H.P.,  $5;  1/16  H.P.,  $4.  Other 
prices  on  application.  A.  J.  Temps,  1690  Grove 
St.,  Brooklyn,  N.Y. 


FOR  SALE  OR  EXCHANGE— Tungsten  steel 
magnets',  lifts  30  lbs.,  $1;  Telephone  magnetos, 
75c;  Automobile  Transformers,  $2.50;  6  volt 
Starter-motor,  $15;  generators,  $15  and  $8;  Small 
motor-generator,  $1;  Battery  charging  outfit  for 
Fords,  $6.50,  automobile  magnetos,  coils  and  parts, 
cheap.  Want  coils,  Volt  and  Ammeters.  Albert 
Onody,  336  Oak  Street,  Buffalo,  N.Y. 

BOYS  ATTENTION!  Owing  to  demand,  we 
have  added  a  wireless  table  with  cabinet  cover  to 
our  list  of  knocked  down  furniture.  Price  from 
$1  up.  Send  for  descriptive  circular..  Stevenson 
Mfg.  Co.,  459  Tehama  St..  San  Francisco,  Cal. 

YOU  MLTST  send  stamped  envelope  for  list  of 
Wireless,  Electrical,  Mechanical  goods.  Carroll, 
Valley  City,  N.Dak. 


CEMENT — Best  for  Experimenters,  sure  sticker. 
Formula  50c.     M.  Blain,  Barre,  Vt.  

FOR  SALE — Tested  galena,  20c.  per  piece. 
Only  silver  accepted.  Alvin  Manternach,  17729 
Windward  Rd.,  Cleveland,  Ohio.   

THE  POPULAR  -APRIL  SPECIAL  extended 
thru  May.  Specially  selected  Audion  FREE  with 
every  order  for  the  ultra-sensitive  "PARAGON" 
Amplifying  Short  Wave  Receiver  at  $35.  15,000 


meter  loose  couplers,  $11.50.  Complete  audion 
sets  potentiometer  equipt,  for  damped  and  un- 
damped signals,  with  "B"  batteries  and  selected 
two  filament  bulb,  $12.95.  Send  stamp  for  new 
catalog  of  QUALITY  apparatus.  Arthur  B. 
Church,  Lamoni,  Iowa. 

SPECIAL — Oscilaudion  bulbs  for  $4.75  each. 
Regenerative  sets  with  detector  $50.  Undamped 
sets  $40  complete.  Let  us  know  your  needs  and 
we  will  quote  you.  Radio  Equipment  Co.,  104 
Fifth  Ave.,  New  York.  Cable  address  RECO, 
N.Y.  

OBTAIN  RESULTS  with  Stratton  Apparatus: 
Tuner,  $6  50.  Send  2c  stamp  for  price  list. 
Stratton  Electric  Company,  215  Federal  Street, 
Greenfield,  Mass.  

LEUMITE — the  new  detector  mineral,  sensi- 
tive, staple.  Send  25c.  for  generous  guaranteed 
piece.  Leumas  Laboratories,  1261  Park  Ave.,  New 
York.  . 

ONLY  $21.75?  Gee!  Paid  $24  for  mine! 
Where'd  you  get  'em  ?  From  POWELL,  agent 
for  36  companies.  Send  him  return  postal  for 
bargain  prices  on  any  radio  instrument  made. 
216  Spruce,  Takoma  Park,  Md. 

NEVER  BEFORE!  Galena  detector,  extremely 
sensitive,  next  to  permanent,  holds  adjustment  for 
weeks,  39c.  prepaid.  Lenzite  detectors,  $4.25. 
Kinderhook  Electrical  Agency,  Kinderhook,  N.Y. 

WOOD  PARTS  for  4.000  M.  coupler  finished 
in  beautiful  polished  mahogany,  size  18x7x7^4  in. 
While  they  last,  with  blue  prints,  98c.  Include 
postage  for  three  pounds.  Louis  E.  Schwab,  3708 
Brooklyn  Ave.,  Cleveland,  Ohio. 

VACUUM  DETECTOR  CIRCUITS— for  bulb 
and  tubular  types,  damped  and  undamped  waves. 
Very  latest.  Complete  with  full  descriptions,  50c. 
No  stamps.    L.  H.  Reiner,  Bexley.  Ohio.  

WIRELESS  KITES— Manufacturers  of  kites  of 
every  description  for  every  purpose.  Do  you 
want  to  hear  from  POZ?  Write  us,  Dept.  E., 
Frank  G.  Seyfang,  1465  Broadway,  New  York 
City.  

BAER  ELECTRIC  CO.,  Van  Wert,  Ohio- 
Special  this  month:  8  V.,  18  W.,  Bell  Transform- 
ers, rings  10  bells  continuously,  best  quality,  fine 
finish;  each,  $1.30.  Satisfaction  guaranteed; 
prompt;  money  refunded  if  not  well  pleased. 
Write  for  our  price  list  of  high  quality  supplies. 

RADIO  QUESTIONS  answered  free.  Send  2c. 
stamp  for  reply.  Hinz  Electrical  Co.,  234  Palmer 
Ave..  Syracuse,  N  Y.  

FOR  SALE — Fifty  Ford  spark  coils  excellent 
for  small  sending  station,  $1 ;  without  vibrator, 
75c;  large  static  machine,  $5;  also  $26  melophone 
horn,  $12.  Write  for  list.  Sidney  Collisson, 
Keokuk,  Iowa. 

GET  BETTER  RESULTS  by  using  a  sterling 
silver  detector  spring,  25c.  prepaid.  Guaranteed 
to  be  sterling  silver.  Address,  Malcolm  Burton, 
1157  Third  Ave.,  Salt  Lake  City.  Utah.  

QUALITY  AND  LOW  PRICE  combined. 
Judge  for  yourself  by  some  of  these  prices:  Au- 
dion panels  with  knob-controlled  rheostats  and 
high  voltage  batteries,  $7.  5,000  meters  cabinet 
set  with  combination  perikon  detector,  $15. 
"Reco"  2-slide  tuner  set,  $3.50.  12-inch  2-sIide 
tuner,  $1.75.  Send  for  literature.  _  Lathe  and 
specification  work  done.  Radio  Equipment  Co., 
179  East  115th  St,  New  York  City. 


You  benefit  by  mentioning  "The  Electrical  Experimenter"  when  writing  to  advertisers. 


MURDOCK 

NO.  55 


SENSIBLY 

PRICED 

SENSITIVE 

RADIO 

RECEIVERS 


GOOD  ENOUGH 
FOR  ANY  STATION 


WHY  PAY  MORE? 


Description 


Real  Radio  Receivers 

THE  BEST  VALUE 
IN  THE  WORLD 


WILL  YOU  TRY  A  SET? 

Or  will  you  simply  read  this  advertisement  and  say, 

"It  sounds  well — but  " 

There  is  no  "BUT"  in  our  GUARANTEE.  We 
positively  guarantee  that  BETTER  'PHONES  CAN- 
NOT BE  OBTAINED  at  these  prices.  We  uncondi- 
tionally guarantee  your  satisfaction. 

GET  A  SET  FOR  TRIAL 

Send  us  a  money  order  for  the  price  of  the  set  you 
select.  It  will  be  shipped  to  you  at  once.  Try 
the  set  thoroughly  for  TWO  WEEKS.  Then,  if  you 
are  dissatisfied  with  it  in  ANY  way,  send  it  back  and 
your  money  will  be  refunded  immediately. 

ORDER  YOUR  SET  NOW 

Prices  on  all  other  MURDOCK  APPARATUS  have 
been  advanced.  Circular  16,  showing  NEW  LIST 
PRICES,  will  be  sent  on  application. 


Patented  "SOLID"  construction  with 
absolutely  permanent  adjustment.    Hard  \A/li/l  |tf|  I  I  O  T\  {T% |£  f\ 

rubber  composition  cases.    Genuine  copper  §  WIYI.    %|.    mUK&JUUrV  OU. 

cod  windings.    Special  thin  diaphragms.  55  Carter  Street,  CHELSEA,  MASS. 

Nickel-plated  split  head  band.    5  foot  mer-  j§| 

cerized  cord  and  special  connection  block.  M     221  Second  Street  San  FrancisCO 


iJVE  minutes  of  actual  practice  prop- 
erly directed  is  worth  more  to  a  man 
than  years  and  years  of  book  study. 
Indeed,  Actual  Practice  is  the  only  train- 
ing of  value,  and  graduates  of  New  York 
Electrical  School  have  proved  themselves 
to  be  the  only  men  that  are  fully  qualified 
to  satisfy  EVERY  demand  of  the  Elec- 
trical Profession. 

At  this  "Learn  by  Doing"  School  a 
man  acquires  the  art  of  Electrical  Draft- 
ing; the  best  business  methods  and  ex- 
perience in  Electrical  Contracting,  together 
with  the  skill  to  install,  operate  and  main- 
tain all  systems  for  producing,  transmit- 
ting and  using  electricity.  A  school  for 
Old  and  Young.    Individual  instruction. 

Letters  from  Successful 
Men 

"I  have  done  well  since  leaving  school  and 
am  now  Superintendent  of  the  light,  telephone 
and  steam  heat  company  here." 

"Ten  months  after  I  left  you  I  was  given 
charge  of  this  station.  J  saved  at  least  3 
years  by  taking  your  course  instead  of  work- 
ing up  as  an  apprentice." 

"I  have  sole  charge  of  all  motors,  lights,  elec- 
trical devices  and  appliances,  and  in  being  able 
to  hold  this  position  1  give  all  credit  to  the 
New  York  Electrical  School  and  your  personal 
interest  in  me,  which  until  lately  I  did  not 
realize  would  be  so  wonderfully  beneficial  to 


"We  had  no  electrical  experience  before  tak- 
ing your  course  and  just  one  year  since 
leaving  school  are  working  side  by  side  with 
men  of  from  five  to  ten  years'  experience." 

"Since  graduating  from  your  school,  I  have 
been  able  to  hanrne  successfully  any  problem 
that  has  come  before  me  in  my  line  of  electri- 
cal work  and  I  wish  to  express  my_  feelings 
for  the  school  and  its  methods  of  training." 

New  York  the  Center 

We  are  located  in  the  heart  of  New  York- 
City  and  you  can  see  the  advantage  of  that. 
New  York  is  the  heart  of  everything  electrical 
— there  are  big  plants  nearby,  electrical  ex- 
positions, libraries  and  facilities  for  good, 
quick  work  in  an  atmosphere  of  industry. 

A  large  number  of  our  students  come  from 
other  cities,  from  all  over  the  United  States. 
Thev  realize  the  advantage  of  coming  to  New 
York  to  learn  electricity.  About  4,500  in  all 
have  gone  out  from  our  school  into  success. 
You  can  do  the  same.  We  believe  that  with 
us  you  can  learn  more  thoroughly  and  more 
quickly  than  anywhere  else  because  we  give 
you  practice.  We  teach  you  only  what  you 
use. 


And  Now 


If.  you  have  an  ambition  to  make  a  name 
for  yourself  in  the  electrical  field  you  will 
want"  to  join  the  New  York  Electrical  •  School. 
It  will  be  an  advantage  to  you  to  start  at 
once.  Then  you  should  hurry  to  send  for 
our  64-page  book  which  tells  you  all  about 
the  school,  with  pictures  of  our  equip- 
ment and  students  it  work,  and  a  full  de- 
scription of  the  course.  You  need  not  hesi- 
tate to  send  for  this  book.  It  is  FREE  to 
everyone  interested  in  electricity.  It  will  not 
obligate  you  to  send  for  it.  Send  the  coupon 
or  write  us  a  letter.  But  write  us  now  while 
you  are  thinking  about  the  subject  of  elec- 
tricity. 

School  open  to  visitors  9  A.  M.  to  9  P.  M. 


New  York  Electrical  School, 

29  W.  17th  St.,  New  York,  N.  Y. 

Please  send  FREE  and  without  obligation  to  me  your  64-page  book. 


Name 


Address. 


is 


NEW  YORK  ELECTRICAL  SCHOOL 
29  WEST  1715  ST., 

NEW  YORK,  N.Y. 


JUNE,  1917  -  IS  CENTS 


★  LARGEST  CIRCULATION  OF  ANY  ELECTRICAL  PUBLICATION 


Th  Is  is  the  Electrical  Age,  and  this  wonderful  new  profession  is  calling  yon.  The 
demand  for  expert  Electricians  is  greater  every  year  and  the  salaries  higher.  Elec- 
tricity is  truly  the  greatest  motive  power  in  the  world,  to-day,  and  now  is  the  time  to 
enter  this  profession. 


YOU  CAN  DO  THIS 


You  can  earn  $36  to  $100  a  week  and  more  as  an  Expert  Electrician.  If  you  have  a 
common  school  education  1  can  train  you  in  a  few  months  at  home.  Big  lighting  and 
power  companies,  municipalities,  and  manufacturers  are  always  seeking  trained  men  to 
handle  their  Electrical  problems. 

I  Guarantee  Satisfaction 

Every  student  receives  our  Sealed  Guarantee  Bond,  which  guarantees  to  return  every  penny  of  his 
money  if  he  is  not  entirely  satisfied.  No  other  school  has  made  this  wonderful'- offer,  but  I  know  the 
success  I  have  brought  to  hundreds  of  my  students,  and  I  know  what  I  can  do  for  any  ambitious  young 
man  who  will  give  me  a  little  of  his  spare  time  each  day 

FREE  ELECTRICAL  OUTFIT 


_  J^!A!  LJTHJ S  CO U  PON 

Dept.  36, 

CHIEF  ENGINEER.  Chicago  Engineering  Works, 
439   Cass   St.,   Chicago,  Illinois. 

Without  obligation  on  my  part  kindly  send  at  once,  fully  prepaid, 
particulars  of  your  complete  Practical  Home  Study  Course  in  Elec- 
tricity. 

Name   

Address   

Town    State  


For  the  next  30  days  I  am  giving-  each  student  an  Outfit  of 
Electrical  Testing  Instruments,  Tools,  Electrical  materials,  and 
Motor  absolutely  Free.  My  instruction  is  by  practical  methods  and 
this  outfit  is  used  in  working  out  the  lessons.  Practical  training 
with  the  theory  makes  perfect.  I  am  Chief  Engineer  of  the  Chicago 
Engineering  Works,  and  I  can  give  you  the  training  that  will  land 
the  big  jobs  and  hold  them. 

If  you  are  in  real  earnest  I  want  to  send  you  my  new  Book — 
"How  to  Become  an  Electrical  Expert."  It's  free.  No  matter 
how  many  other  schools  you  write  to  I  want  you  to  have  my  book 
— It's  different  because  it's  practical — Write  today. 

CHIEF  ENGINEER  COOKE 

CHICAGO  ENGINEERING  WORKS 


Dept.  36 


439  CASS  STREET,  CHICAGO,  ILL. 


Van  benefit  by  mentioning  "The  Electrical  Experimenter"  when  writing  to  advertisers. 


June,  1917 


THE  ELECTRICAL  EXPERIMENTER 


81 


AVIATION 

PRACTICAL  AERONAUTICS  BY  MAIL 

%'Earn  $50  to  $500  a  Week! 

TJTERE  is  the  one  inexhaustible  gold  mine  of 
opportunity  and  here  is  the  man  who  will 
lead  you  to  it.  It  is  the  most  extraordinary  con- 
dition ever  presented,  owing  to  the  sudden 
world-wide  demand  for  aeroplanes.  High 
class  positions  by  the  thousand  calling  for 
trained  men — fame  and  fortune  actually  thrust 
at  them.  Salaries  of  from  $50  to  $500  a  week  are 
awaiting  men  who  can  fill  these  positions.  And 
now,  for  the  first  time  in  history,  a  practical,  home- 
study  course  in  practical  aeronautics  is  open  to 
every  man  at  a  trifling  expense.  No  matter  what 
your  occupation,  you  can  prepare  for  a  better  posi- 
tion with  big  pay.   Now  is  your  opportunity. 

Enter  a  practically  untrodden  field — a  new 
profession.  Seize  the  opportunity  that  has  burst  upon  the  country  with  tremendous  force.  Hustle 
ahead  with  the  rapid  development  of  the  aeroplane  industry  which  is  outrivaling  that  of  automo- 
bile and  motion  picture,  as  the  quick  and  sure  road  to  financial  independence. 


BUD  MORRISS,  Chief  Instructor  American  School  of  Aviation 


Prepare  NOW 

for  these  positions 

Aeronautical  Engineer 
Aeronautical  Instructor 
Aeronautical  Contractor 
Aeroplane  Repairman 
Aeroplane  Mechanic 
Aeroplane  Inspector 
Aeroplane  Salesman 
Aeroplane  Assembler 
Aeroplane  Builder 


Conducted  by  Famous 
Aviators  and 
Aeroplane  Builders 

The  Course  has  been  prepared 
by  men  of  international  reputation.  Mr. 
Bud  Morriss,  the  well-known  aviator,  is  Chief 
Instructor  and  personally  guides  the  progress 
of  each  student.  He  is  assisted  by  a  distin- 
guished staff  of  Aviators,  Aeroplane  manu- 
facturers and  Aeronautical  Engineers.  Every 
Lesson,  Lecture,  Blue  Print  and  Bulletin  is 
self-explanatory  in  plain  terms  for  quick  under- 
standing. The  Course  is  absolutely  up-to-the- 
minute  with  every  known  fact  concerning 
Aeronautics.  You  get  practical,  working 
knowledge  of  the  very  highest  merit.  Now  is 
the  time  and  this  is  your  opportunity  to  step 
right  into  fame  and  fortune.  You  are  needed. 
Where  there's  a  will  here's  the  way. 


What  Our  Students  Say: 

Mr.  Stanfield  Fries 

Fort  Bliss,  Tex. 
My  estimation  of  the  new  course 
is  excellent ;  it  could  positively  not 
be  any  better. 

Mr.  Z.  Purdy 

Shreveport,  La. 
It  is  hard  to  believe  that  lessons 
on  such  a  subject  could  be  gotten  up 
in  such  an  interesting  manner. 
Mr.  Lloyd  Royer 

Haigler,  Neb. 
I  can  hardly  thank  you  enough  for 
the  way  you  have  personally  taken 
up  my  enrollment. 

Mr.  Mayne  Eble 

Manistee,  Mich. 
I  believe  I  learn  more  from  my 
lessons  than  an  aviator  who  takes 
his  first  lesson  with  an  airman  in 
an  aeroplane. 


Write  Now  for  Our  Great  Offer  a^.""" 

▼  of  Aviation 

Send  the  coupon  for  full  particulars  of  our  remarkable  special   ♦      431  so.  Dearborn  st. 
offer  open  to  you  now.    Find  out  all  about  the  marvelous  opportunities  f  DePl-  8036 

that  are  opening  in  the  Aviation  game.  This  offer  is  the  greatest  stepping  stone  to  ^  Chicago,  III. 

bigger  opportunities  ever  known.  Write  today  for  complete  literature,  all  free  ^  Gentlemen:  Please  send  me  free 
and  prepaid.    You  are  not  obligated  in  any  way.    Do  not  waste  time  in  thinking   ^    and  without  obligation,  full  particu- 

about  it.  Act !  Send  the  coupon  or  a  letter  or  a  post  card  will  do.  Write  at  once.    *7  la"  of  y°ur  CouQrse  l.n1PA%ctlc!1  Y,er°" 

1  1  ▼  nautics  and  your  Special  Offer  to  those 

*  •  c   \        1       c    a     •    •  •  ▼   who  write  at  once. 

American  ochool  or  Aviation  + 

Dept.  8036     CHICAGO,  ILL.  aw 
HHHHH^BMHHHIHHflRMMHIHHBH^  .-/(Mn'.s.v  


431  So.  Dearborn  Street 


You  benefit  by  mentioning  "The  Electrical  Experimenter"  when  writing  to  advertisers. 


82 


THE  ELECTRICAL  EXPERIMENTER 


June,  1917 


FREE!  20  lessons 


Write  me  at  once — TODAY!  Just  send  the  coupon  or  a  postal.  I  will  give  you 
20  complete  lessons  in  practical  electricity  FREE !    Think  of  it !    My  personal  and 

individual  instruction  for  20  lessons  without  a  cent  of  cost  to  you  if  you  act  quick.  No  charge  to  you  for 
these  20  lessons  now  or  later.  I  make  this  sensational  offer  to  secure  a  few  more  live  students — to  show, 
too,  how  quickly  I  can  make  you  a  Master  Electrician  no  matter  where  you  live,  or  what  you  do.  But  you 
must  act  at  once!  This  offer  closes  in  23  days!  Remember  these  free  lessons  are  not  merely  sample 
lessons,  but  are  a  regular  part  of  my  fall  and  complete  course  in  electricity.  Send  the  coupon  without 
delay— TODAY! 

Earn  $2,500  to  $4,000  a  Year 

You  can  now  qualify  at  home  during  your  spare  time,  and  without  giving  up 
your  present  position  or  occupation,  for  that  most  wonderful  of  all  fields  open  to  the 
ambitious  man — the  great  and  growing  field  of  Electricity!    Yes,  no  matter  if  you  don't  know  a  thing  about 
electricity  or  never  had  a  bit  of  electrical  experience,  I  will  take  you  in  hand  and  make  you  an  Expert 
Electrician  so  that  you  should  easily  earn  $2,500  to  $4,000  a  year  and  more.    And  Til  do  it  so  quickly 
and  with  so  little  effort  on  your  part,  that  you'll  wonder  how  it  was  possible.    No  books  or  tools  to  buy. 

I  Train  You  By  Mail!  Men  Wanted 


Formerly  with  the  General 
Electric  Co.;  former  General 
Manager  of  company  manu- 
facturing Jenney  Electric  Mo- 
tors; also  formerly  with  Fair- 
banks,Morse  &  Co.;  now  Con- 
sulting Engineer  and  Director 
of  the  Wicks  Electrical  Insti- 
tute. 


I  will  instruct  you  personally — make  the  whole 
matter  so  simple  for  you  that  you.  can't  help  but 
learn.  When  you  have  finished  my  instructions 
you  are  an  Expert  Electrician — ready  to  take  a 
big  paying  job  or  start  in  for  yourself.  I  show 
you  not  only  how  to  do  practical  electrical  work, 
but  how  to  estimate  on  jobs  so  that  you  can  take 
contracts  at  big  profits.  That's  what  it  means 
to  be  trained  by  a  man  of  my  practical  experience. 


Wherever  you  go  there's  always  urgent  demand 
for  Expert  Electricians  and  at  big  pay.  That's 
because  the  watchword  of  the  age  is,  "DO  IT 
ELECTRICALLY."  The  field  of  electricity  is 
broadening  so  fast  that  there's  a  big  shortage  of 
competent  electricians.  And  the  demand  is  in- 
creasing every  day. 


Mail  Coupon  Today 


A.  W.  WICKS,  E.  E.,  Director,  Wicks  Electrical  Institute 
81  W.  Randolph  St.  Dept.  296  Chicago,  111. 

Without  any  obligation  to  me  whatever,  please  send  me  full  descrip- 
tion of  your  personal  instructions  in  Electricity  and  particulars  of  your 
special  offer  of  20  of  your  lessons  free. 

Name  

Street  and  No  

City  State  


I 


YOU  MUST  ACT  QUICK 

Mail  coupon  today.  I  want  to  hear  from  you  immediately.  _  Don't  miss 
my  offer  of  20  personal  lessons  free.  Remember  this  offer  is  strictly  limited 
to  23  days.  Write  for  all  particulars  at  once.  Here's  your  chance!  No 
obligation  to  you.    Send  coupon  or  postal  NOW! 

A.  W.  WICKS,  E.  E.,  Director 

Wicks  Electrical  Institute 

81  W.  Randolph  St.,  Dept.  296  Chicago,  III. 


You  benefit  by  mentioning  "The  Electrical  Experimenter"  when  writing  to  advertisers. 


ram 


233  FULTON  STREET,  NEW  YORK 

Publisht  by  Experimenter  Publishing  Company,  Inc.  (H.  Gernsback,  President;  S.  Gernsback,  Treasurer;)   233  Fulton  Street,  New  York 


Vol.V    Whole  No.  50 


CONTENTS  FOR  JUNE,  1917 


No.  2 


ELECTROCUTING    THE    ENEMY  Front  Cover 

From  a  painting  by  George  Wall 
ELECTRIC     CROSSING     SIGNAL    OPERATED     BY  TRAIN'S 

WHISTLE  By    George    Wall  85 

CHANCES    FOR    ELECTRICIANS    IN    THE    NAVY   86 

^TALKING   MOTION   PICTURES   VIA  WIRELESS   87 

ELECTRICITY  AND  WATER  TO  RUN   OUR  AUTOS   88 

SHOOTING  WITH  ELECTRICITY  By  Hugo  Gernsback 

ELECTRICITY'S    AID    TO    WOMEN  •  

POWERFUL    HYDRO-ELECTRIC    SALVAGE    APPARATUS  TO 
RAISE  SUNKEN  SHIPS.  .  .By  H.  Winfield  Secor,  Assoc.  A.I.E.E. 
ELECTRO-DEPOSITED    MIRRORS   NOW   USED   FOR  PHOTO- 
GRAPHIC WORK   

"JOE'S  EXPERIMENT"— An  electrical  story  by  C.  M.  Adams   100 

ELECTRICITY  AND  LIFE  By  Dr.  Frederick  Finch  Strong  104 

EXPERIMENTAL    PHYSICS— LESSON     5,  "HYDROSTATICS" 

By  John  J.  Furia,  A.B.,  M.A.,  F.K.S.  106 


90  - 
92 


hi 


97 


DENVER   WIRELESS    STATION   WINS   PRIZE   LOVING  CUP 

By  W.  H.  Kirwan 

THE  NAVAL  RADIO  OPERATOR— WHAT  THE   U.   S.  NAVY 

OFFERS   TO   RADIO  MEN  

REMARKABLE  RADIO  OUTFIT  BUILT  BY  GERMAN  SPY... 

THE  MARCONI  TYPE  "106"  TUNER  By  Worth  MacKnight 

THE  HOW  AND  WHY  OF  RADIO  APPARATUS— NO.  4  SPARK 

GAPS    113 

THE  CLOCK  CRAZE  By  Thomas  Reed  114 

THE  INFLUENCE  OF  LIGHT  UPON  THE  CONTACT  POTEN- 
TIAL OF   SELENIUM   AND   OF   CUPROUS  OXID  

By  E.  H.  Kennard  and  E.  O.  Dieterich 

HIGH  FREQUENCY  APPARATUS   AND  EXPERIMENTS  

By  Hubert  A.  Mcllvaine 

THE  PROBLEM  OF  USING  THE  ENERGY  IN  SUNLIGHT  

By  Prof.  I.  Thornton  Osmond 

EXPERIMENTAL    CHEMISTRY— THIRTEENTH  LESSON  

By  Albert  W.  Wilsdon  123 


107 

108 
110 
112 


116 
117 


118 


Silencing  America's  Wireless 


W 


S  all  our  readers  are  aware  the  United 
States  Government,  thru  the  Navy  Depart- 
ment, has  issued  orders  thruout  the  land  to 
cause  the  immediate  dismantling  of  all  radio 
stations, 

whether    large       £■  ■■■■  "in  n.nnnin.ui  m.i  .  mil"  

or  small,  com-  | 
mercial  or  amateur,  send- 
ing or  receiving.  All 
aerials  have  been  ordered 
dismantled  and  apparatus 
packed  away. 

This  action  came  as  a 
great  surprise  to  all  pa- 
triotic amateurs,  who  for 
years  past  had  been  en- 
couraged by  the  Govern- 
ment and  who  were  cer- 
tain that  in  time  of  war 
they  would  be  allowed  to 
"do  their  bit"  with  their 
outfits  for  the  country. 

That  the  Government 
should  silence  all  sending 
outfits  was  eminently 
proper,  and  we  have  as  yet 
to  hear  the  first  complaint 
on  that  score.  But  why 
the  receiving  outfits  should 
be  dismantled  by  the  Navy  § 

Department  is  very  puz-     f,  ,  ..„„  ,  mm  „„„  murm  u  

zling  indeed. 

President  Wilson's  Executive  Order  is  based  upon 
the  Radio  Act  of  1912,  which  act  however,  mentions 
nothing  about  closing  receiving  stations  during  the  time 
of  war.  That  purely  receiving  stations  were  considered 
harmless  by  the  framers  of  the  law,  is  best  proved  by 
the  fact  that  such  stations  do  not  require  to  be  licensed 
as  do  all  sending  stations.  Moreover,  in  President  Wil- 
sons's  Executive  Order  of  April  6,  no  mention  is  made 
of  receiving  stations.  Indeed,  the  following  passage 
strikes  us  as  very  significant : 

"  and  furthermore  that  all  Radio  Stations  not  nec- 
essary to  the  Government  of  the  United  States  for  Naval  Com- 
munications may  be  closed  for  radio  communication." 

The  italics  are  ours.  Particularly  the  one  word  MAY. 
In  the  same  paragraph  the  President  uses  the  command 
SHALL,  while  the  word  may  does  not  imply  that  every 
radio  station  should  be  taken  over  by  the  Navy  Depart- 
ment.   Indeed,  the  longer  we  study  the  third  paragraph 


EXECUTIVE  ORDER 

HEREAS  the  Senate  and  House  of  Representatives  of  the 

1,  have 
United 


United  States  of  America,  in  Congress  assembled,  have 
declared  that  a  state  of  war  exists  between  the 


States  and  the  Imperial  German  Government;  and 

Whereas  it  is  necessary  to  operate  certain  radio  stations 
for  radio  communication  by  the  Government  and  to  close  other 
radio  stations  not  so  operated,  to  insure  the  proper  conduct  of 
the  war  against  the  Imperial  German  Government  and  the 
successful  termination  thereof 

Now,  therefore,  it  is  ordered  by  virtue  of  authority  vested 
in  me  by  the  Act  to  Regulate  Radio  Communication,  approved 
August  13,  1912,  that  such  radio  stations  within  the  jurisdic- 
tion of  the  United  States  as  are  required  for  Naval  Communi- 
cations shall  be  taken  over  by  the  Government  of  the  United 
States  and  used  and  controlled  by  it,  to  the  exclusion  of  any 
other  control  or  use;  and,  furthermore,  that  all  radio  stations 
not  necessary  to  the  Government  of  the  LTnited  States  for 
Naval  Communications  may  be  closed  for  radio  communication. 

The  enforcement  of  this  order  is  hereby  delegated  to  the 
Secretary  of  the  Navy,  who  is  authorized  and  directed  to  take 
such  action  in  the  premises  as  to  him  may  appear  necessary. 

This  order  shall  take  effect  from  and  after  this  date. 
The  White  House, 
6  April,  1917. 


of  the  President's  Executive  order,  the  more  we  become 
convinced  that  the  closing  of  every  amateur  station,  or 
even  commercial  stations,  was  remote  from  President 
Wilson's  mind  when  he  issued  his  order. 

In    conformity    to  the 

 i  ni  s     Radio   Act   of    1912,  the 

I  President  in  time  of  war, 
may  authorize  any  depart- 
ment of  the  Government 
to  close  all  radio  stations. 
But  the  President's  order 
of  April  6,  was  not  to  the 
Department  of  Commerce, 
which  in  the  past  con- 
trolled the  nation's  radio 
affairs,  but  to  the  Navy 
Department.  Why?  Be- 
cause the  President,  it 
seems  to  us,  had  only  the 
radio  communications  of 
the  Navy  in  mind.  If, 
therefore,  the  Navy  De- 
partment had  caused  the 
closing  of  all  radio  sta- 
tions, particularly  sending 
stations  along  our  sea 
borders,  such  action  would 
have  seemed  perfectly  log- 
|.  ical.  But  why  the  Navy 
1     Department    should  wish 

.in....  mm"......!...  „  ,„„„,„„,  ii 1 1 ii  mil     to  close  stations  a  thousand 

miles  removed  from  the 
sea  borders,  seems  to  us  very  puzzling.  Furthermore, 
why  all  college  radio  stations,  and  those  belonging  to 
radio  apparatus  manufacturers  as  well,  should  be  dis- 
mantled seems  far  fetched.  Then  there  are  cases  like 
the  one  of  the  Lackawanna  Railroad,  which  is  one  of  the 
pioneer  railroads  in  the  United  States  to  use  wireless 
for  train  dispatching.  Is  it  wise  to  dismantle  such  sta- 
tions on  which  the  safety  of  passengers  depends? 

We  certainly  have  no  quarrel  with  the  Navy  Depart- 
ment ;  quite  the  contrary.  We  wish  to  help,  but  we  sin- 
cerely do  hope  that  its  officials  will  soon  find  a  way  to 
modify  its  recent  sweeping  order. 

There  are,  indeed,  encouraging  signs  already.  Cer- 
tain commercial  stations  on  the  Pacific  Coast  have  re- 
cently resumed  operation,  and  it  is  to  be  hoped  that 
amateurs  will  be  allowed  to  operate  their  receiving  sta- 
tions, at  a  not  too  distant  future.         H.  Gernsback. 


(Signed)    Woodrow  Wilson. 


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83 


84 


THE  ELECTRICAL  EXPERIMENTER 


June,  1917 


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THE.  ELECTRICAL 
EXPERIMENTER 


H.  GERN5BRCK  editpr 

H.  W.  5ECC7R  dSSDCIftTE  EDITC7R 


Vol.  V.    Whole  No.  50 


June,  1917 


Number  2 


Electric  Crossing  Signal  Operated  by  Train's  Whistle 

By  GEORGE  WALL 


ANEW  YORK  genius  has  developed 
a  clever  idea  for  automatically 
sounding  the  alarm  at  railroad 
■  crossings,  and  whereby  the  alarm 
is  controlled  and  actuated  by  the 
whistle  of  the  approaching  train  itself. 
The  accompanying  illustration  shows  how 
the  inventor  proposes  to  mount  a  number 
of  large  size  horns  along  the  crossing- 
approaches,  each  horn  being  fitted  with  a 
super-sensitive  electrical  microphone,  such 


the  sensitive  reed  relay,  the  latter  closes 
the  proper  circuits  to  a  powerful  electric 
siren  installed  at  the  top  of  the  signal 
tower  at  the  railroad  crossing,  as  shown 
in  the  accompanying  illustration  and  dia- 
gram of  the  elemental  circuits.  For  night 
requirements,  the  alarm  may  consist  of  the 
electric  siren  and  a  powerful  beam  of  light, 
both  of  which  are  projected  out  of  the  sig- 
nal horn.  The  siren  is  enabled  to  project 
its  sound  out  into  the  horn  past  the  incan- 


such  as  a  slow-moving  dash-pot  attached 
to  the  sensitive  relay,  so  that  the  relay 
could  not  open  the  siren  and  lamp  circuits 
for  a  period  of  a  minute  or  so ;  thus  mak- 
ing certain  that  the  signal  will  sound  until 
the  train  has  past  the  crossing.  The  idea 
is,  all  in  all,  quite  novel  and  possesses 
many  other  possibilities. 

The  microphone  has  proven  its  worth  in 
man}'  difficult  roles  in  industrial  as  well 
as  military  and  naval  operations.    The  sol- 


Instead  of  Having  the  Gateman  Sound  the  Alarm  at  Railroad  Crossings  This  Inventor  Proposes  That  Sensitive 
Microphones   be    Erected    Along   the   Crossing    Approaches,  the  Sound  of  the  Locomotive's  Whistle  Causing  Them 
to  Actuate  a  Relay  Device  Connected  to  an  Automatic  Crossing  Signal. 


as  used  in  the  well-known  Dictagraph. 
When  the  train  whistle  sounds  for  the 
crossing  these  microphones,  scattered  along 
a  distance  of  several  hundred  feet  on  either 
side  of  it,  pick  up  the  sounds  and  are 
caused  to  control  a  sensitive  relay  device 
operating  on  the  tuned-reed  principle.  The 
relay  will  thus  respond  with  maximum  effi- 
ciency to  a  certain  whistle  tone,  as  the 
vibrating  reed  armature  fitted  to  it  is 
selected  to  vibrate  sympathetically  with  the 
dominant  note  of  the  locomotive  whistle. 

When  the  approaching  train's  whistle  has 
thus  actuated  the  microphone  and  in  turn 


descent  lamp,  as  the  latter  is  mounted  on 
a  perforated  disc,  thus  allowing  the  sound 
waves  to  pass  by  it.  The  alarm  tower  may 
carry  two  or  more  of  these  combined  elec- 
tric siren  and  lamp  signals,  and,  as  be- 
comes evident,  the  operation  of  the  device 
is  extremely  efficient ;  the  alarm  ceases  as 
soon  as  the  train  has  past  the  crossing. 

There  are,  of  course,  several  details 
which  are  not  shown  in  the  accompanying 
view,  which  would  be  necessary  in  carry- 
ing out  and  applying  the  plan  here  pro- 
posed. For  one  thing  there  would  have 
to  be  some  form  of  time-element  device 


diers  in  Europe  have  found  the  sensitive 
microphone  of  extreme  value  in  listening 
to  enemy  sappers  as  they  picked  and 
shoveled  a  mine  below  the  listeners.  Again 
the  French  have  been  enabled  to  accurately 
locate  and  "spot"  an  enemy  submarine  off 
shore  by.  suitably  disposing  two  or  more 
specially  tuned  microphones  along  the  coast 
at  a  known  distance  apart.  Then  by  a  sim- 
ple triangulation  computation  on  a  clever 
slide  rule,  the  distance  at J which  the  sub- 
marine happened  to  be,  is  readily  found, 
and  a  fast  patrol  scout  will  be  waiting  for 
her    when    she    arrives    at    the  surface. 


86 


THE  ELECTRICAL  EXPERIMENTER 


June,  1917 


Chances  for  Electricians  in  the  Navy 


The  U.  S.  Navy  now 
offers  excellent  chances 
to  ambitious  young  men 
who  have  a  desire  to 
learn  a  trade  and 
learn  it  right.  The  na- 
val electrician  has  un- 
equaled  opportunities 
for  attaining  an  ex- 
ceedingly broad  and 
substantial  elec- 
trical knowledge, 
covering  dyna- 
mos and  mo- 
tors, wiring  of  all  kinds,  special  and 
standard  signaling  systems,  telephone 
systems,  radio  apparatus,  and  a  host 
of  other  things  with  which  the  aver- 
age "land-lubber"  may  never  become 
thoroly  familiar.  U.  S.  naval  elec- 
tricians never  need  to  fear  that  they 
can  not  land  a  job  after  their  service 
in  the  navy  is  finished. 

Naval  service  offers  many  induce- 
ments to  ambitious  and  spirited 
young  men.  Not  only  does  it  provide 
opportunities  for  free  travel  in  many 
nearby  and  distant  waters  with 
changing  scenes,  but  it  furnishes  ex- 
cellent training  of  high  value  in  civil 


tors  in  use  for  ventilating  blowers,  ammu- 
nition hoists  and  conveyors,  gun-pointing 
equipments,  turret-turning  machinery,  and 
various  other  purposes.  These  motors  are 
supplied  thru  special  control  apparatus  from 
turbogenerators,  engine-driven  dynamos, 
motor-generators,  etc.  The  lighting  equip- 
ment includes  incandescent  and  arc  lamps, 
searchlights  of  the  highest  powers,  special 
signal  lamps,  etc.    Communication  appara- 


consequently  the  training  and  experience 
received  in  their  operation  and  main- 
tenance are  of  exceptional  value  to  the 
electrician  or  radio  operator  in  after  life. 

Since  the  proper  operation  and  care  of 
all  the  varied  electrical  apparatus  is  essen- 
tial to  the  efficiency  of  the  Navy,  it  is  the 
practise  to  send  all  new  recruits  for  this 
branch  of  the  service  to  either  of  the  two 
Navy    Electrical    Schools    at    the  navy 

  yards  at  Brooklyn,  N.  Y.,  and  Mare 

Island  (San  Francisco),  Cal.  These 
schools  provide  instruction  in  two 
classes,  general  electrical  work  and 
radiotelegraphy.  The  length  of  the 
full  course  for  both  classes  is  eight 
months.  Men  specially  proficient  in 
the  work  pass  thru  this  period  in 
shorter  time,  depending  on  the  knowl- 
edge and  skill  they  show.  All  stu- 
dents, either  recruits  or  men  from 
the  general  service,  may  enter  these 
schools  at  any  time.  In  addition  to 
the  practical  instruction  imparted  at 
the  electrical  and  other  naval  trade 
schools  and  training  stations,  the  men 
receive  thruout  their  service  aboard 
ship  and  elsewhere  both  academic  and 
practical  training  to  enable  them  to 
demonstrate  their  ability  and  to  ad- 


Another  View  of  the  Electrical  School 
at  Mare  Island,  Calif.,  Class  Receiving 
Instruction    in    Electrical  Appliances, 
Including  Electric  Searchlights. 

pursuits  at  the  conclusion  of  enlist- 
ment. It  also  furnishes  steady, 
healthful  work,  free  board  of  a 
wholesome  nature,  free  lodging  and 
clothing,  and  in  addition  provides 
pay,  even  during  the  period  of  train- 
ing, that  can  be  practically  all  set 
aside  for  saving.  The  United  States 
Navy  pays  its  enlisted  men  better 
than  any  other  national  navy  and 
in  most  lines  more  than  the  men 
could  save  and  in  some  cases  even 
more  than  they  would  receive  in 
similar  pursuits  in  civil  life.  Above 
all  this  it  enables  the  men  to  render 
the  highest  patriotic  service  open  to 
the  citizens  of  any  nation,  that  of 
defending  the  security  of  their  coun- 
try in  the  first  line  of  defense. 

The  many  uses  of  electricity  aboard 
ship  and  in  the  naval  stations  have 
been  steadily  increasing.  It  is  used 
not  only  for  lighting  and  power 
service,  but  also  for  communication 
signaling,  and  even  for  cooking  and 
ing.    There  are  a  multitude  of  electric 


Top: — View  in  Navy  School,  New  York,  Class  in  Interior 
Communication  and  Ship  Control   Apparatus.     Below: — 
Testing  Dynamos  and  Motors. 


and  tits  consists  chiefly  of  telephones  and  radio- 
bak-  telegraphic  sets.  Machinery  and  apparatus 
mo-     in  use  in  the  Navy  are  of  the  highest  types, 


Uncle    Sam's    Naval    Men  Receiving 
Training  in  the  Operation  of  Electric 
Generators    in    the    Navy    School  at 
Mare  Island,  Calif. 


vance  in  their  chosen  vocation. 

In  order  that  a  recruit  may  en- 
list for  the  electrical  branch,  he  must 
have  a  knowledge  of  either  general 
electricity,  or  be  an  operator  of  the 
Morse  telegraph  code  or  have  suffi- 
cient foundation  in  radiotelegraphy  to 
be  competent  to  keep  up  with  the 
class  at  the  school.  Electricians  (gen- 
eral) must  know  the  names  and  uses 
of  the  various  parts  of  the  dynamo 
and  dynamo-driving  engines  and 
must  be  familiar  with  the  ordinary 
types  of  switchboards  and  methods  of 
wiring.  Applicants  for  both  classes 
must  be  able  to  write  legibly,  must 
understand  elementary  arithmetic  and 
must  be  between  the  ages  of  18  and 
25.  All  applicants  must  be  citizens 
of  the  United  States,  either  native 
or  fully  naturalized. 

Recruits    meeting    these  require- 
ments are  immediately  transferred  to 
the  electrical  school,  where  the  course  of  in- 
struction   comprises    machine-shop  work, 
(Continued  on  page  142) 


June,  1917 


THE  ELECTRICAL  EXPERIMENTER 


87 


Talking  Motion  Pictures  Via  Wireless 


MANY  of  us  have  no  doubt  wit- 
nessed an  exhibition  of  talking 
motion  pictures,  and  numerous 
patents  have  been  taken  out  on 
some  very  elaborate  schemes  in- 
tended to  improve  the  efficiency  of  the  ap- 
paratus involved  in  recording  and  repro- 
ducing the  voice,  as  well  as  the  figures  of 
photoplay  productions. 

One  of  the  most  novel  ideas  devised  to- 
ward accomplishing  this  purpose  is  out- 
lined in  a  recent  patent  awarded  to  Wil- 
liam B.  Vansize,  of  Brooklyn,  N.  Y.  The 
accompanying  illustration  by  our  artist 
shows  how  the  inventor  proposes  to  utilize 
and  apply  the  art  of  radio  communication 
to  the  recording  and  reproduction  of  talk- 
ing motion  pictures.  In  the  first  place,  the 
studio  stage  is  fitted  with  a  metal  floor, 
such  as  one  covered  with  tin  or  sheet  iron. 


diated  thru  a  ground  wire  leading  to  metal 
plates  (and  points  if  necessary)  on  the 
heels  of  the  actors,  as  shown,  and  also 
thru  a  miniature  antenna  comprising  a 
series  of  tin-foil  leaves  which  are  sewn 
in  the  clothing  in  the  manner  indicated  in 
the  accompanying  illustration.  The  radio 
apparatus  is  carried  in  the  clothing,  and 
the  weight  of  each  part  distributed  in  the 
best  manner  possible.  As  will  be  noted 
the  batteries  are  placed  somewhat  differ- 
ently in  the  case  of  a  lady,  as  compared 
to  a  man. 

Thus  far  we  see  that  whenever  the  ac- 
tors speak,  that  they  will  be  radiating  wire- 
less telephone  currents,  and  these  are  in- 
tercepted or  picked  up  by  a  larger  radio 
antenna  erected  back  of  or  just  above  the 
scenic  settings  of  the  studio  stage  in  the 
manner  illustrated.    The  stage  antenna  is 


a  corresponding  record  of  their  voices  on 
the  moving  steel  wire  of  the  telegra- 
phone,  which  has  been  explained  in  detail 
in  previous  issues  of  this  journal. 

In  brief,  the  telegraphone  operates 
upon  the  principle  that  if  a  moving  steel 
wire  is  past  by  the  pole  of  an  electro- 
magnet thru  which  electrical  voice  currents 
are  circulating,  then  there  will  be  local 
magnetisations  set  up  in  the  steel  wire 
corresponding  to  the  voice  fluctuations.  If 
then  we  afterward  pass  this  steel  wire 
under  another  electro-magnet,  the  coil  of 
which  is  connected  to  a  telephone  receiver, 
we  can  then  hear  the  voice  reproduced. 

The  great  problem  confronting  all  in- 
ventors who  take  up  talking  motion  pic- 
ture work  is  to  accurately  and  practically 
synchronize  the  motion  picture  voice  with 
the  voice  of  the  actor.    This  is  the  most 


T^e  °.1e  Great  Problem  m  "Talking"  Motion  Pictures  Lies  in  the  Difficulty  of  Simultaneously  Recording  the  Voice  and  the  Scene.  A 
New  Method  of  Accomplishing  This  End  Is  Illustrated  Here.  Each  Actor  Carries  a  Radio-Telephone  Transmitter  on  His  Person.  His  Wire- 
less Love  and  Other  Speeches  Are  Intercepted  by  a  Stage  Antenna,  Connected  to  a  Radio  Receiving  Set.  This  Set  Is  Connected  to  a 
Telegraphone  Joined  Mechanically  to  the  Motion  Picture  Camera.    Thus  Synchronism  Between  Voice  and  Picture  Is  Established. 


This  may  be  painted  so  as  to  give  the 
effect  of  ±ile  or  carpet,  and  may  have  a 
few  rugs  scattered  about  to  give  an  artis- 
tic stage  setting.  The  small  insert  illus- 
tration shows  how  the  inventor  proposes 
to  have  each  actor  actually  personify  "a 
walking  wireless  station."  In  brief,  each 
actor  carries  a  complete  wireless  transmit- 
ting system  on  his  person.  When  the  ac- 
tor speaks,  the  voice  waves  affect  a  super- 
sensitive microphone  hidden  inside  the  coat 
or  m  the  bodice,  in  the  case  of  a  woman. 
This  microphone  is  connected  to  some 
form  of  miniature  wireless  transmitting  ap- 
paratus, such  as  an  Oscillion  or  vacuum 
bulb  generator  of  radio  currents.  The  voice 
fluctuations  are  caused  to  vary  the  cur- 
rent developed  by  the  Oscillion,  and  these 
fluctuating,  high  frequency  oscillations  cor- 
responding of  course  to  the  voice,  are  ra- 


connected  up  thru  suitable  timing  coils, 
with  an  oscillation  or  vacuum  bulb  de- 
vice, which  is  used  in  this  case  as  a  de- 
tector and  amplifier  of  the  received  radio- 
telephonic  currents. 

Now  we  have  the  actor's  voice  radiated 
by  wireless  from  his  own  person,  thence 
propagated  thru  space  by  etheric  waves, 
and  finally,  we  have  them  coming  in  thru 
the  receiving  circuit  of  the  stationary  radio 
detector.  The  secondary  or  auditory  cir- 
cuit of  the  detector  and  amplifier  is  con- 
nected with  the  recording  electro-magnets 
of  a  Poulsen  telegraphone,  mounted  in- 
tact on  the  motion  picture  camera  which 
is  recording  the  scene  photographically. 
Thus,  as  the  photographer  turns  the  handle 
on  the  motion  picture  camera,  he  not  only 
records  the  physical  movements  of  the  ac- 
tors,  but   simultaneously  he   also  obtains 


important  problem,  and  by  means  of  this 
wireless  telephonic  arrangement,  as  pro- 
posed by  Mr.  Vansize,  it  seems  that  it 
should  become  a  simple  matter  to  readily 
accomplish  the  purpose  intended,  viz.,  to 
record  and  reproduce  faithfully  a  talking 
motion  picture,  and  one  in  which  the  ac- 
tors' lips  will  not  be  moving  about  ten 
seconds  after  the  voice  is  heard  or  vice 
versa. 

In  practise  a  number  of  loud-speak- 
ing telephones  are  scattered  about  the  mov- 
ing picture  theatre,  and  as  the  operator 
cranks  his  machine,  the  telegraphone  wire 
is  unreeled  at  exactly  the  same  speed.  The 
impulses  from  the  recorded  telegraphone 
wire  now  are  used  to  operate  the  loud 
talkers  about  the  house,  with  the  result 
that  the  audience  sees  and  hears  the  ac- 
tors in  a  truly  remarkable  manner. 


88 


THE   ELECTRICAL  EXPERIMENTER 


June,  1917 


Electricity  and  Water  to  Run  Our  Autos 


GASOLINE  forms  the  nucleus  of 
power  in  practically  all  automobile 
engines  of  the  present  day,  and 
many  inventors  and  chemists  have 
expended  considerable  energy  and 
money  in  an  effort  to  find  a  satisfactory 
substitute  for  this  all-important  commodity, 
which  has  been  rapidly  and  constantly  in- 
creasing in  cost.  One  of  the  latest  attempts 
in  this  direction  is  that  of  Mr.  Ernest  E. 
Punches,  who  hails  from  Detroit,  Michi- 
gan. 

"Give  me  a  suitable  tank  containing  a  set 
of  plates  submerged  in  water  and  a  source 
of  electric  current,  and  I  will  drive  your 


close  arrangement  of  the  positively  and 
negatively  charged  electrodes,  the  gas  gen- 
eration is  both  rapid  and  efficient. 

As  before  mentioned  the  oxygen  is  liber- 
ated by  suitable  automatic  valves,  and  the 
hydrogen  is  retained  and  past  thru  a  mixing 
valve,  similar  to  the  usual  carburetor  used 
on  all  gasoline  engines  and  which  can  be 
controlled  from  the  driver's  seat,  follow- 
ing the  standard  practise  in  motor-car  equip- 
ment. A  suitable  quantity  of  air  is  taken 
in  thru  the  mixing  valve,  and  which,  when 
combined  with  the  proper  quantity  of  hy- 
drogen, forms  a  highly  explosive  gaseous 
compound.    When  this  is  fed  into  the  en- 


load.  The  motor  develops  45  h.p.  on  an 
average  at  this  speed,  and  under  full  load, 
with  a  well  worked  in  motor.  The  suction 
displacement  per  revolution  is  244/2  equals 
112  cubic  inches;  equals  .0648  cubic  feet. 
Then  at  3,000  revolutions  per  minute  and 
assuming  100  per  cent  volumetric  efficiency, 
the  number  of  cubic  feet  drawn  into  the 
motor  per  minute  is  3,000  times  .0648,  or 
194.5,  and  60  times  194.5,  or  11,670,  is  the 
number  of  cubic  feet  drawn  into  the  motor, 
of  mixture  each  hour,  running  at  maximum 
speed  and  under  full  load. 

The  gasoline  entering  into  that  mixture 
is  7  per  cent  by  weight,  and  the  amount  by 


/NT/) HE  M/JN/FOLDcJr 
TO  Cr UNDER 


EIIR  AND  G/PS 

MIXER, 


MIXER 
^CONTROL 


DYN/PMO 


A  Detroit  Genius  Claims  to  Have  Solved  the  "Gasoline  Substitute"  Problem  for  Automobiles.  He  Utilizes  a  Very  Simple  Electrical  Phenom- 
enon— That  of  "Electrolysis"  or  the  Decomposition  of  Water  by  the  Passage  of  An  Electric  Current  Thru  It.  The  Hydrogen  Gas  Evolved 
Is  Mixed  With  Air  and  Past  Into  the  Engine  Cylinders.     The  Inventor  States  That  It  Is  More  Economical  Than  Gasoline  Because  of  the 

Higher  Explosive  Value  of  the  Hydrogen-Air  Mixture. 


automobile  engine  without  any  gasoline 
whatsoever  at  reduced  cost,"  says  this  san- 
guine inventor. 

The  secret  of  this  remarkable  invention 
lies  in  the  fact  that  if  an  electric  current 
is  past  between  two  plates  submerged  in 
water,  it  decomposes  the  water,  evolv- 
ing two  gases,  oxygen  and  hydrogen  ;  the 
oxygen  accruing  from  this  process  is  liber- 
ated, while  the  hydrogen  is  collected  and 
when  suitably  mixed  with  a  proper  amount 
of  air,  it  forms  a  highly  explosive  mixture 
when  ignited  in  the  automobile  engine  cylin- 
der. 

The  accompanying  illustration  shows  how 
the  proposed  water-electric  gas-generating 
plant  would  be  fitted  to  a  motor-car,  the 
special  dynamo  together  with  the  decom- 
posing chamber  and  gas  storage  tank  being 
placed  with  the  engine  under  the  same  bon- 
net. The  small  Unipolar  type  dynamo  is 
connected  by  suitable  gears  or  driving 
chain  to  the  timing  gear  on  the  crank  shaft 
of  the  engine,  and  supplies  a  low  voltage 
direct  current.  This  current  is  past  thru 
the  electrolytic  cell  shown  in  the  illustra- 
tion, alternate  plates  being  charged  posi- 
tively and  negatively.  The  plates  are  pre- 
ferably perforated  so  as  to  promote  circula- 
tion in  the  gas-generating  cell,  and  by  the 


gine  cylinders  and  ignited  by  an  electric 
spark,  it  produces  a  force  many  times  more 
powerful  than  that  obtained  when  gasoline 
vapor  is  used.  Some  of  the  hydrogen  gas 
produced  by  the  electrolytic  cell  (decompo- 
sition of  water)  is  stored  in  a  suitable  tank 
under  pressure,  which  makes  it  available 
for  starting  the  car  and  emergency.  The 
entire  combination  unit  fits  the  carburetor 
side  of  the  engine  and  is  supported  by  the 
former  manifold  holding  means  and  also 
by  the  frame  of  the  auto  chassis.  It  has 
been  found  by  Mr.  Punches  from  trial  and 
also  by  calculation,  that  the  hydrogen  gas- 
generating  outfit  here  described,  and  which 
it  is  proposed  to  substitute  for  gasoline,  will 
require  up  to  5  per  cent  of  the  horse-power 
developed  by  the  engine,  this  5  per  cent  of 
the  total  engine  horse-power  being  used  to 
drive  the  decomposing  current  dynamo. 

There  are  1,257.52  cubic  feet  of  hydrogen 
gas  in  one  cubic  foot  of  water,  the  gas  at 
atmospheric  pressure,  zero  degree  Centi- 
grade, and  it  will  require  1,728  watts  of 
electricity  to  decompose  a  cubic  foot  of 
water  in  one  hour.  Compare  this  with  the 
following  data,  obtained  from  a  Chalmers 
Motor  Car  Company  engineer : — 

The  maximum  revolutions  of  the  Chal- 
mers motor  is  3,000  per  minute  under  full 


volume  will  not  depart  far  from  the  7  per 
cent,  as  there  is  no  great  difference  between 
the  weight  of  air  and  gasoline  vapor.  So, 
in  face  of  the  fact  that  an  explosion  of 
hydrogen  in  a  pure  state,  when  mixed  with 
air,  is  a  thousand  times  as  powerful,  as  is 
the  same  per  cent  of  gasoline  vapor  and 
air,  we  shall  be  way  above  in  figuring  a  10 
per  cent  mixture  of  hydrogen  gas  with  air. 
As  10  per  cent  of  11,670  is  1,167,  the  number 
of  cubic  feet  of  hydrogen,  we  must  generate 
in  an  hour.  Bearing  in  mind  that  there  are 
1,257.52  cubic  feet  of  hydrogen  in  a  cubic 
foot  of  water,  and  that  1,728  watts  will  de- 
compose the  cubic  foot  of  water  in  an  hour, 
and  also  that  746  into  1,728  goes  about  2}4 
times,  it  is  apparent  that  we  will  generate 
90.52  cubic  feet  of  gas  per  hour  more  than 
the  Chalmers  motor  can  use  at  maximum 
speed,  and  under  full  load,  taking  less  than 
5  per  cent  of  the  45  h.p.  to  drive  the  decom- 
posing current  generator.  The  inventor  has 
demonstrated  his  invention  before  the  entire 
engineering  staff  of  the  Tecla  Electrical 
Laboratory  of  Detroit,  Michigan. 

When  it  is  understood  that  gasoline  is 
simply  a  mechanical  mixture  of  hydrogen 
and  carbon  gases  and  impurities,  it  will  be 
seen  that  a  mixture  of  pure  hydrogen  gas 
(Continued  on  page  145) 


June,  1917 


THE  ELECTRICAL  EXPERIMENTER 


89 


OPTICAL  DEVICE  THAT  RIVALS 
TELESCOPE  IN  STUDYING 
THE  HEAVENS. 

An  optical  device,  which  is  said  to  rival 
if  not  surpass  the  telescope  in  revealing 
the  mysteries  of  the  heavenly  bodies  was 
exhibited  at  a  recent  meeting  of  the  Amer- 
ican Society  of  Mechanical  Engineers  in 
New  York.  The  invention  was  exhibited 
by  Dr.  John  A.  Brashear,  the  grand  old 
man  of  American  astronomy,  of  Pittsburgh. 

"This  instrument  is  called  a  diffracting 
grating,"  said  Doctor  Brashear,  as  he 
showed  what  looked  like  a  rectangular 
piece  of  metal  about  2  by  4  inches  long 
that  changed  colors  under  the  electric 
lights.  "On  the  plane  surface  of  this  pol- 
ished plate,  made  accurate  to  one-tenth  of 
a  light  wave,  or  within  one-forty-five-thou- 
sandth of  an  inch,  are  ruled  more  than 
45,000  lines  between  which  there  is  no 
greater  error  than  one-two-millionth  of  an 
inch. 

"With  this  delicate  piece  of  apparatus, 
made  possible,  first  by  rigorous  scientific 
research;  second,  by  the  skill  of  the 
artisan ;  third,  by  a  knowledge  of  a  vigor- 
ous care  to  avoid  temperature  changes, 
and,  fourth,  by  the  accuracy  of  the  mech- 
anism, the  astrophysicist  has  been  able  to 
tell  the  composition,  temperature  and  dis- 
tance of  the  stars." 


GOVERNMENT  TAKES  OVER 
MARCONI  STATIONS. 

The  U.  S.  Government  has  availed  it- 
self of  the  offer  of  the  Marconi  Wireless 


Todd,  at  Washington,  will  have  charge  of 
stations  operated  by  the  government.  En- 
rollments will  be  made  by  commands  of 
naval  districts.  t 


REVIVING  THE  CHAIN  SHOT  TO 
DESTROY  RADIO  AND  OTHER 
AERIAL  WIRES. 

An  American  inventor  has  recently  pro- 
posed that  the  military  and  naval  authori- 
ties revive  a  relic  of  warfare  which  was  in 
vogue  many  years  ago — this  is  nothing 
less  than  the  generally  well-known  chain 
shot.  In  our  grandfathers'  and  great-grand- 
fathers' day  it  was  considered  quite  a 
nifty  idea  to  tie  one  or  more  cannon  balls 
together  with  an  iron  chain — thus,  the  name 
chain  shot.  The  accompanying  illustration 
shows  a  clever  form  of  split  projectile 
composed  of  three  or  more  pieces  divided 
in  the  manner  shown,  so  that  by  means, 
of  a  time  fuse  or  other  arrangement,  these 
pieces  would  fly  thru  the  air  as  a  solid 
projectile,  and  at  the  critical  moment  would 
explode  and  describe  a  path  of  consider- 
able width  thru  the  atmosphere,  and  prov- 
ing, it  would  seem,  of  decided  efficiency 


To  Counteract  the  Poisonous  Gas  Fumes  Blown  Toward   European  Trench    Rescuers  Who 
Are  Called   Upon  to  Go  Forth  and   Carry   Prostrate  Soldiers   From  Their  Positions,  They 
Have  Guarded  Themselves  Against  Being  Overcome  by  a  Novel  Telephone  Appliance  At- 
tached   to    the    Gas    Defying  Equipment. 


Telegraph  Company  of  America,  placing 
its  staff  and  stations  at  its  service  and  has 
taken  over  for  the  period  of  the  war  not 
only  the  Marconi  stations  but  all  other  ra- 
dio stations  for  military  purposes.  The 
eligible  operators  will  be  enrolled  in  the 
government  service.  Stations  not  required 
will  be  closed.  The  trans-Pacific  stations 
will  continue  handling  commercial  traffic, 
but  under  government  supervision.  No 
ship  traffic  will  be  permitted  on  the  At- 
lantic and  Gulf  Coasts  and  the  Great  Lakes 
excepting  for  the  government,  but  it  will 


EUROPEAN    SOLDIERS    USE  GAS 
MASKS   FITTED   WITH  TELE- 
PHONES. 

The  accompanying  illustration  shows  in 
a  marked  manner  one  of  the  peculiar  and 
particularly  effective  scientific  devices 
brought  out  by  the  great  European  war. 

Needless  to  say  this  war  of  all  wars  has 
developed  hundreds,  even  thousands,  of  new 
inventions  of  every  conceivable  character. 
First  the  Germans  invented  the  gas  ap- 
paratus by  which  they  attempt  to  overcome 
their  enemies  in  the  trenches  with  clouds 
of  noxious  fumes,  and  here  we  have  the 
answer  to  this  challenge  in  the  form  of  a 
gas  mask  or  helmets,  which  are  worn  by 
the  members  of  the  trench  rescue  brigade, 
who  are  called  upon  to  go  forth  and 
carry  prostrate  soldiers  from  their  posi- 
tions where  they  may  have  fallen  between 
the  trenches,  when  overcome  by  the  gas 
cloud.  Each  gas  helmet  and  mask  is  fit- 
ted with  a  novel  and  specially  designed 
telephone  outfit,  properly  connected  to  a 
trailing  wire  leading  back  to  the  trench, 
so  that  the  rescuers  are  able  to  telephone 
for  aid  without  removing  their  helmets  or 
apparatus. 


A  New  War  Invention  Is  a  Split  "Chain  Shell"  That  Automatically  Explodes  at  a  Given 
Range.     It  Should  Prove  Particularly  Valuable  In  Destroying  Radio  Antennae  and  Other 

Wire  Structures. 

in  destroying  radio  antennae,  and  all  other  continue  for  the  present  on  the  Pacific, 
elevated  wire  structures  such  as  telegraph  Trans-Atlantic  traffic  via  _  Glace  Bay  will 
and  telephone  wires,  power  transmission  not  be  disturbed.  The  Director  of  Naval 
circuits,  et  cetera.  Communications,    Lieutenant  Commander 


GOVERNMENT  RADIO  BILL  GOES 
OVER. 

House  leaders  at  Washington  have  de- 
cided definitely  not  to  pass  at  this  session 
the  Administration  bill  for  permanent  Gov- 
ernment dictatorship  over  wireless  appara- 
tus, unless  the  President  specifically  re- 
quests it. 

It  was  learned  that  the  House  Mer- 
chant Marine  Committee  believes  the  Presi- 
dent already  has  power  enough  over  radio 
stations  to  prevent  their  use  in  time  of 
war. 

The  principal  feature  of  the  bill  is  its 
provision  for  eventual  Government  owner- 
ship of  radio  companies.  This  feature  is 
not  considered  by  the  committee  to  be 
strictly  war  legislation. 


90 


THE  ELECTRICAL  EXPERIMENTER 


June,  1917 


Shooting  With  Electricity 


YEARS  ago,  when  the  New  York 
City  elevated  lines  changed  from 
steam  to  electricity,  one  of  the  ele- 
vated trains  caught  fire.  An  alarm 
was  promptly  turned  in  and  in  due 
time  the  firemen  were  on  the  spot.  The 
stream  from  the  high-pressure  hose  was 
played  on  the  cars,  and  to  prevent  the  fire 
from  reaching  the  wooden  structure  on 
which  the  rails  rested,  as 
well  as  the  wooden  foot  — — — . 
path,  one  of  the  firemen  of 
necessity  directed  his 
stream  on  the  third  rail. 

The  stars  are  not  in- 
tended to  indicate  what 
happened  and  what  that 
poor  fireman  saw ;  rather 
they  are  meant  to  illustrate 
how  long  he  remained  un- 
conscious. As  a  matter  of 
fact  the  man  was  almost 
electrocuted.  Since  that 
time  firemen  do  not  fight  — ^— — — 
elevated  fires  unless  they 
are  assured  that  the  power  has  been  turned 
off. 

Now,  the  N.  Y.  Elevated  Lines  only  carry 
500  volts  direct  current,  but  this  pressure 
is  sufficient  to  pass  from  the  third  rail 
line,  then  to  the  water  of  the  fire  hose, 
and  from  there  into  the  metallic  nozzle 
held  by  the  fireman.  Altho  ordinary  hy- 
drant water  is  a  poor  conductor,  a  500-volt 
current  nevertheless  finds  but  little  trouble 
in  passing  thru  the  stream  of  water  and 
thence  thru  the  body  of  the  fireman,  with 


By   H.  Gernsback 

liquid  fire  is  sprayed  upon  the  enemy,  be- 
ing a  parallel  to  the  writer's  scheme.  While 
shooting  flames  over  a  distance  of  50  feet 
or  more  has  not  proven  a  wonderful  suc- 
cess, nevertheless  the  idea  seems  to  have 
some  merits.  And  if  the  Germans  can  shoot 
flames  at  us,  why  can't  we  return  the  com- 
pliment by  shooting  electricity  at  them? 
One  is  as  easy  as  the  other,  with  a  few 


If  AVE  you  ever  stopt  to  consider  that  a  fireman  does  not  dare  to  let 
a  stream  of  water  from  a  nozzle  strike  an  electric  wire,  carrying 
any  appreciable  potential,  say  a  thousand  volts  or  more,  as  he  may  be 
electrocuted.  Proverbially  speaking,  it  is  a  poor  rule  that  will  not  work 
both  ways.  Hence  we  have  the  unique  proposal  by  Mr.  H.  Gernsback, 
that  we  charge  the  enemy  with  highly  electrified  streams  of  acidulated 
water  under  high  pressure.  This  unusual  invention  is  not  intended  as  a 
substitute  for  guns,  but  to  supplement  them.  It  represents  one  answer 
to  the  German's  "Flammen  Werfer" — Liquid  fire. 


points  in  favor  of  the  latter,  it  would  seem. 

Briefly,  the  idea  is  as  follows :  Strapt  to 
a  soldier's  back  is  a  lead-lined  metal  tank 
carrying  a  solution  of  diluted  sulfuric  acid 
of  about  1200°  specific  gravity.  (A  solution 
of  chlorid  of  zinc  or  even  ordinary  salt 
water  could  be  used.)  By  turning  a  knob 
on  the  outside  of  the  tank  a  small  quan- 
tity of  zinc  or  iron  filings  is  thrown  into 
the  acid  and  immediately  hydrogen  gas  is 
evolved,  causing  considerable  pressure  in- 
side of  the  tank.     This  causes  the  acid 


lines)  there  is  a  10-H.P.  gas  engine  driv- 
ing a  5-  to  8-H.P.  Alternating  Current 
Generator.  The  latter  is  connected  to  a 
step-up  transformer  delivering  from  10,000 
to  15,000  volts.  A  thin  but  extremely  well 
insulated  cable  connects  with  the  nozzle 
carried  by  the  soldier.  This  cable  is  con- 
nected to  one  side  of  the  transformer ; 
the  other  pole  is  grounded  to  earth.  If 
now  the  stream  hits  an 
— — — 2——  enemy  soldier  (who  is  not 
insulated  from  the 
ground),  the  high-tension 
current  passing  thru  the 
stream  of  highly  conduc- 
tive acid,  runs  thru  the 
man's  body  and  thence 
thru  the  earth,  back  to  the 
transformer.  In  this  case 
he  probably  will  be  elec- 
trocuted or  else  knocked 
senseless  by  the  powerful 
current.  Even  standing  on 

  a  piece  of  dry  wood  or  a 

— ~~~ ~ ~~ — —  stone  will  not  help  him, 
for  the  acid  running 
down  from  his  uniform  will  turn  the  wood 
or  the  stone  into  an  excellent  conductor 
and  the  enemy  will  almost  certainly  be  ren- 
dered unconscious.  Probably  the  most  effi- 
cient way  of  utilizing  the  new  scheme  will 
be  found  in-  directing  the  charged  stream 
at  a  machine  gun.  The  second  the  stream 
hits  the  metallic  portion  of  the  gun,  the 
operators  will  be  knocked  unconscious  or 
will  even  be  killed.  It  is  also  understood 
that  the  entire  electrocuting  outfit,  gaso- 
line engine,  dynamo,  transformer,  acid  tank 


The  Germans  Invented  "Liquid  Fire"  With  Which  to  Destroy  the  Enemy.  Here  Is  An  American  Invention— Shooting  the  Enemy  With 
Piercing,  H igh- Pressure  Acid-Water  Streams  Charged  to  An  Electric  Potential  of  15,000  Volts.  Trench  Gasoline  Engine,  Electric  Plants 
and  Transformers  Supply  the   Necessary  Power.     The   Nozzles  Are  Heavily  Insulated  and  the  Soldiers  Wear  Heavy  Rubber  Shoes  As 

Well  As  Gloves  and  Masks. 


the  result  that  he  is  knocked  unconscious. 
If  the  stream  had  been  sea  (salt)  water, 
there  remains  little  doubt  but  that  the  man 
would  have  been  electrocuted  instantly. 

Upon  this  principle  the  writer  has  based 
his  idea  of  shooting  electricity  at  an  enemy, 
impracticable  as  the  scheme  sounds  at  first 
thought.  Many  murderous  ideas,  of  course, 
have  been  advanced  for  trench  warfare, 
the    German    Flammen    Werfer,  whereby 


to  be  forced  out  thru  the  hose  attached 
to  the  tank  and  from  the  hose  the  acid 
passes  thru  the  long  nozzle  carried  by  the 
soldier.  The  acid  leaves  in  a  fine  stream, 
less  than  a  quarter  of  an  inch  in  diameter, 
and  with  a  fairly  calm  atmosphere,  it  should 
carry  from  75  to  100  feet.  For  most  pur- 
poses, 50  feet  however,  will  probably  be- 
found  sufficient. 
Now,  back  in  the  trench  (or  behind  the 


and  all  the  rest  of  the  equipment  could  be 
placed  in  an  armored  car.  In  that  case, 
the  operators  would  not  be  exposed  to  ma- 
chine gun  fire. 

When  used  by  the  soldier,  however,  it 
is  self-evident  that  his  equipment  must  be 
such  that  he  himself  will  not  be  electro- 
cuted. To  that  effect  he  wears  a  special 
"high-tension"  rubber  shoe,  capable  of  with- 
standing 20,000  volts.*  '  Then  too  he  uses 
"high-tension"  rubber  gloves,  and  in  addi- 


• 


June,  1917 


THE   ELECTRICAL  EXPERIMENTER 


91 


The  Best  Way  to  Aid  the  President 

By  HOWARD  H.  GROSS, 
President  Universal  Military  Training  League 


AFIXT  military  policy  which  will 
protect  the  nation  and  strengthen 
her  manhood  is  the  special  need 
of  the  hour.  Each  passing  day 
demonstrates  this.  This  League 
and  its  sponsors  believe  that  in  universal 
military  training  lies  the  na- 
tion's chief  hope.  They  there- 
fore urge  two  things : 

First  and  foremost :  Stand 
behind  President  Wilson  in 
every  way.  He  is  bearing  a 
tremendous  burden.  Assist 
him  in  all  emergency  meas- 
ures, whether  financial,  mili- 
tary or  economic. 

Second :  Use  every  influ- 
ence to  impress  upon  our 
Senators  and  Representatives 
in  Congress  that  emergency 
war  measures  now  pending 
will  not  solve  our  military 
needs  except  temporarily. 
They  may  carry  the  country 
along  for  the  present,  but 
they  will  not  do  for  the  fu- 
ture. The  most  democratic 
program  as  a  fixt  military 
policy  for  the  United  States 
is  that  of  universal  compul- 
sory military  training.  It 
treats  all  alike,  makes  use  of 
young  men  before  they  reach 
the  age  where  their  earning 
capacity  is  high  and  when 
they  are  yet  unmarried,  and 
gives  them  six  months'  intensive  military 
training.  Then  it  sends  them  back  to  work. 
These  trained  youth  will  form  the  backbone 
of  a  great,  democratic  citizen  army.  This 
is  the  only  definite,  simple  and  patriotic  plan 
that  will  make  America  safe  and  ready. 

I  earnestly  hope  that  every  American 
will  stand  by  President  Wilson  and  the 
Government  officials  who,  with  the  Presi- 
dent, are  bearing  a  gigantic  responsibility. 
I  have  just  returned  from  the  national 
capital  and  I  know  and  sense  in  a  measure 
the  weight  that  is  taxing  our  silent  and 
conservative  Chief  Executive.  It  would  be 
shameful  to  see  his  plans  for  meeting  this 
crisis  defeated.  Therefore,  as  should  all 
citizens,  I  bespeak  general  co-operation 
with  President  Wilson  in  these  mighty 
works. 


They  are  emergency  measures,  as  he  has 
said.  This  universal  military  training  plan 
is  supplementary  to  the  President's  emer- 
gency measures.  It  goes  further  and  will 
last  longer.  While  he  is  doing  all  that 
he  can  do  safely  to  pilot  the  ship  of  state 


What  Military  Training  Does  For  a   Man.     Compare  the  Two  Recruits 
on  the  Left  With  the  Two  Erect  Figures  on  the  Right.     They  Are  the 
"Same   Men,"   Photographed   Before  and   Ajter   Being  Trained  for  Five 
Months  in  the  U.  S.  Army. 


thru  the  eddies  just  ahead,  I  ask  all  patri- 
otic citizens  not  only  to  strengthen  his  arm 
in  this  effort,  but  to  aid  the  nation  as  a 
whole  in  supplementing  the  President's  la- 
bors by  the  establishment  of  universal 
military  and  naval  training. 

The  benefits  resulting  from  such  a  demo- 
cratic plan  for  raising  an  army  in  emer- 
gencies cannot  be  over-estimated.  The  last 
few  weeks  have  shown  how  weak  and 
futile  other  devices  have  been.  The  vol- 
unteer system  is  unfair,  and  because  it  is 
so  thousands  of  young  men  who  are  as 
patriotic  and  loyal  as  the  best  in  the  land 
will  not  offer  their  services.  They  have 
come  to  realize  that  the  strong,  highest 
types  of  manhood  go  forward  while  the 
cowards  and  slackers  only  too  gladly  stay 
at  home.    The  best  blood  goes  to  the  front 


while  the  unpatriotic  rejoice  in  secret  in 
the  opportunity  to  remain  safe  and  sound 
at  home,  pile  up  money  and  have  a  good 
time. 

Such  a  false  premium  upon  patriotism 
is  not  only  disgraceful  in  a  national  mili- 
tary program,  but  it  is  de- 
cidedly uneconomical  a  n  d 
wasteful.  In  nine  cases  out 
of  ten  the  slackers  are  able- 
bodied,  and  u  nder  proper 
tutelage  would  make  good 
soldiers,  while  the  patriotic 
fellows  who  rush  to  the  colors 
are  the  sort  who  are  needed 
most  to  man  the  commercial 
and  financial  craft  of  the  na- 
tion. The  best  brains  will  go 
into  the  ranks  as  privates  and 
leave  the  sluggards  at  home 
to  conduct  the  nation's  af- 
fairs. This  is  fundamentally 
bad  in  a  democracy. 

Selective  conscription  n  o 
doubt  may  lie  necessary  at 
times,  but  it  never  will  be 
popular.  Universal  military 
training,  on  the  other  hand, 
is,  thru  its  very  universality, 
plain,  simple  democracy.  It 
says  that  all  having  the  bless- 
ings of  our  institutions 
should,  in  time  of  need,  con- 
tribute their  aid  to  defending 
these  institutions.  It  says, 
further,  that  the  untrained 
soldier  is  so  much  "cannon  fodder,"  and 
that  the  chances  of  the  trained  lad  return- 
ing home  in  health  from  war  are  about 
three  times  greater  than  the  untrained  boy's. 

Therefore,  in  universal  military  training, 
the  secret  of  our  general  military  and  naval 
needs  for  today,  tomorrow  and  All  Time 
is  found. 

The  Universal  Military  Training  League 
makes  special  appeal  to  the  people  of  the 
country  to  write  their  Congressmen  to 
back  President  Wilson  in  all  his  emer- 
gency measures  and  to  eradicate  forever 
the  doubt,  uncertainty  and  weaknesses  of 
present  muddled  military  policy  by  es- 
tablishing in  law  a  fixt  plan  for  universal, 
compulsory  military  training  and  service. 

Stand  by  your  President  and  strengthen 
your  nation  ! 


tion  to  this  the  nozzle  is  heavily  insulated 
from  his  hands  by  means  of  a  special  in- 
sulator, as  grafically  shown  on  our  front 
cover.  The  tank  of  course  must  be  well 
insulated  by  soft  rubber  pads  from  the  back 
o'f  the  operator.  Thus  equipt  he  is  in  little 
danger  of  being  shocked  by  the  current. 

Ia  order  to  prevent  the  wind  from  driv- 
ing his  own  acid  spray  against  the  oper- 
ator's face,  he  is  also  equipt  with  a  soft 
rubber  mask,  as  illustrated  on  our  front 
cover  and  on  opposite  page. 

From  a  humanitarian  standpoint,  the 
scheme  is  far  ahead  of  the  German  flame 
shooter;  sulfuric  acid  of  1250°  does  not 
blind,  nor'  does  it  destroy  animal  tissue, 
unless  it  remains  in  contact  with  it  for  a 
long  period.  Sprayed  on  the  skin,  but 
slightly   itching  results  after  a  lapse  of 


several  minutes.  On  the  other  hand,  the 
high.-tension  current  kills  either  outright, 
or  otherwise  puts  the  enemy  out  of  the 
fighting  for  the  time  being,  with  little 
bad  after-effects.  The  acid,  plus  elec- 
tricity, does  not  cause  horrible  burning 
wounds  or  burned  off  limbs  as  does  the 
liquid  ilame. 

'  A_s  with  all  war-schemes,  the  wise  ones 
will  now  ask  the  usual  question :  What 
happens,  if  the  enemy  too  uses  the  elec- 
trocuting apparatus? 

In  answer  the  writer  asks  another  ques- 
tion:  What  happens,  if  the  enemy  too 
uses  liquid  flames,  or  if  the  enemy  too 
uses  machine  guns? 

*This  shoe  was  described  on  page  24,  May,  1917, 
issue  of  this  journal.  v 


AUXILIARY  SIGNAL  CORPS 
UP-TO-DATE. 

Perhaps  the  finest  single  auxiliary  sig- 
nal corps  possest  by  any  army  has  been 
given  to  the  LTnited  States  by  the  Amer- 
ican Telephone  and  Telegraph  Company. 
About  500  engineers  already  have  been 
selected  and  some  of  them  have  been 
sworn  into  army  service.  The  differences 
between  government  pay  and  their  salaries 
with  the  telephone  companies  will  be  paid 
by  the  latter. 

The  corps  will  be  made  up  of  general 
plant  and  traffic  engineers  'to  plan,  set  up 
and  operate  telephone,  telegraph  and  wire- 
less plants.  If  the  regular  force  of  the 
army  proves  to  be  too  small,  men  also 
will  be  provided  to  assist  in  the  wireless 
work. 


DATE  OF  ISSUE. — As  many  of  our  readers  have  recently  become  unduly  agitated  as  to  when  they  could  obtain  The  Electrical 
Experimenter,  we  wish  to  state  that  the  newsstands  have  the  journal  on  sale  between  the  fifteenth  and  the  eighteenth  of  the  month  in 
the  eastern  part  of  the  United  States  and.  about  the  twentieth  of  the  month  west  of  the  Mississippi  River.  Our  subscribers  should  be  in 
possession  of  their  copies  at  these  dates.  Kindly  bear  in  mind,  however,  that  publications  are  not  handled  with  the  same  dispatch  by  the 
Post  Office  as  a  letter.  For  this  reason  delays  are  frequent,  therefore  kindly  be  patient  and  do  pot  send  us  complaints  as  to  non-arrival 
of  your  copy  before  the  twenty-fifth  of  the  month. 


92 


THE  ELECTRICAL  EXPERIMENTER 


June,  1917 


Elec£ricf£yk  AH  f o  Women 


Here  We  Have  the  Combination  Electrio 
Stove.  Strlpt  for  Action — Said  Action 
Being  That  of  Frying  Eggs.  And  They 
Do  Say  Electrified  Eggs  Taste  the  Best. 


Who  Can  Remember  Ironing  Day  Without 
Wishing  There  Wasn't  Any  Such  Animal. 
But  All  Is  Changed.  Behold  the  Electric 
Ironer  That  Really  Does  Wonderful  Work  at 
4  Cents  an  Hour.  Even  the  Chinaman  Is 
Outdone. 


Do  You  Have  to  Polish  Waxed  Floors?  This  Back-Breaklng 
lask  Is  Now  Accomplished  In  a  Short  Time  and  in  a  Highly 
tmcient  Manner,  by  the  Electric  Motor  Floor-Polisher  Shown. 


Cook  by  Wire — Without  Fire.    The  Com- 

bination     Electric    Table    Stove  Shown 
Above   Enables  You  to   Fry   Eggs,  Broil 
Chops.  Make  Toast.  Boil  Water — Yes.  and 
It  May  Even  Be  Used  as  an  Oven. 


Remember  the  Fellow  Who  Told  the  Waiter  the 
Steak  Was  Too  Rare?     Said  the  Waiter— "We 
Cook  by  Electricity."     "Well.  Give  That  Steak 
Another  Shock,"  Said  the  Patron. 


June,  1917 


THE  ELECTRICAL  EXPERIMENTER 


93 


Electricity's  Place  In  Business 


ELECTRICITY    SPELLS  EFFI- 
CIENCY TO  THE  BOSS 
OF  TO-DAY. 

Efficiency  has  reached  a  very  important 
role  in  modern  industry  where  the  manu- 
facturer manifests  a  desire  to  obtain  the 
maximum  output  of  his  plant  with  a  mini- 
mum input — in  other  words — Efficiency. 
Various  schemes  have  been  promulgated 
in  the  direction  of  increasing  efficiency  in 
machinery  and  it  was  found  that  the  best 
means  which  the  manufacturer  can  em- 
ploy to  determine  the  efficient  output  of 
his  plant  is  to  note  the  actual  productive 
power  of  the  individual  output  of  each 
machine  and  employee.  Schemes  were  in- 
troduced for  this  purpose,  but  the  defects 
encountered  in  them  were  numerous  and 
most  of  which  had  to  be  abandoned  for 
the  purpose  for  which  they  were  made. 

The  distinct  need  of  an  instrument  for 
increasing  the  efficiency  in  productive  plants 
grew  more  and  more  urgent,  which  caused 
a  number  of  prominent  engineers  to  study 
this  rapidly  growing  problem.  This  work 
finally  led  to  the  development  of  an  instru- 
ment called  the  Productograph,  herewith 
illustrated  and  which  has  proved  the  solu- 
tion to  this  absorbing  problem.    The  intro- 


The  Business  End  of  the  Electric  "Producto- 
graph"— the  Instrument  that  Keeps  Tally  on 
the  Daily  Output  of  Each  Worker  in  Shops 
and  Factories. 

duction  of  this  instrument  was  made  pos- 
sible by  the  application  of  electricity. 

The  first  illustration  shows  the  complete 
instrument  which  is  stationed  in  the  man- 
ager's or  superintendent's  office.  It  con- 
sists_  of  a  drum  upon  which  a  sheet  of 
specially  prepared  paper  is  placed.  Over 
this  paper  there  are  ten  recording  needle 
arms,  which  are  actuated  by  electro-mag- 
nets ;  these  are  located  within  the  cabinet. 
Each  needle  is  directed  over  the  proper 
section  of  the  paper  and  each  needle  is 
electrically  connected  to  a  single  machine, 
of  which  the  productive  efficiency  is  to  be 
found.  The  sections  of  the  paper  are  longi- 
tudinally divided  into  24  equal  parts  cor- 
responding to  24  hours.  Each  division  is 
subdivided  into  minutes.  The  cylinder  is 
rotated  by  means  of  an  electric  motor  con- 
nected to  a  standard  clock,  operating  a 
series  of  electrical  contacts.  Normally, 
when  the  needle  arms  are  not  acted  on 
by  the  electro-magnet,  which  is  connected 
to  a  special  switch  attached  to  the  ma- 
chine the  record  of  which  is  to  be  obtained, 
a  straight  line  is  made  and  every,  time 
the  machine  is  in  operation  it  causes  the 
switch  to  close  the  electrical  circuit  period- 
ically, which  operates  the  needle  arm  and 
this  in  turn  traces  a  curve  on  the  paper. 


APPLYING  PSYCHOLOGY  WITH 
THE  ELECTRIC  "PSYCHOMETER." 

The  latest  device  for  testing  speed  and 
quality  of  human  thought  is  the  "Psychom- 
eter,"  which  is 
an  electrical  appa- 
ratus now  being 
used  in  San  Fran- 
cisco, where  it  is 
being  applied  to 
accurately  measure 
the  degree  of 
alertness  in  em- 
ployees in  industrial 
establishments,  a  s 
well  a  s  general 
mental  alertness  in 
all  vocations. 

The  Psychom- 
eter  is  operated  by 
either  alternating 
or    direct  current 
and    may    be  at- 
tached to  the  base- 
board electric  light 
socket.  The  clock- 
work attachments 
and  electrical  con- 
nections are  oper- 
ated by  pressing  a 
simple  telegraph 
key  which  is  con- 
nected   with  the 
baseboard  plug. 
The  instrument  is 
built  in  a  grip  and 
may  be  easily  car- 
ried around.    The  readings  are  made  by 
an  electric  light,  which  is  mounted  on  the 
side  of  the  small  suit  case.    The  instru- 
ment is  an  accurate  gage  of  memory  and 
measures    speed    and   quality   of  thought 
to  the  fifth  of  a  second,  besides  charting 
alertness  and   ability  to   react  quickly  in 
mechanical  work  and  emergency  situations. 

If  the  machine  stops  for  any  reason,  the 
indication   on  the  paper   shows  this  and 
immediately  gives  the  owner_  visual  indi- 
cation of  the  fact.     In  addition  to  this 
equipment,    an    electro-magnetic  counter 
is    connected    to  the 
same  circuit,  which  in- 
dicates the  number  of 
operations  made  by  the 
machine.    Thus,  if  this 
instrument  is  attached 
to  a  printing  press,  it 
will    indicate  exactly 
the  number  of  printed 
sheets  that  the  machine 
has  made  during  a  cer- 
tain   p  e  r  i  od  .  Each 
needle   has    its  corre- 
sponding  counting  in- 
strument and  both  are 
connected  to  a  single 
switch.     This  particu- 
lar   instrument  here- 
with shown  is  adapt- 
able for  ten  machines. 

The  second  photo- 
graph shows  the  adopt- 
ion of  this  device  in 
a  clothing  establish- 
ment, where  it  is  used 
for  checking  up  the 
number  of  coats  made 
by  each  operative. 


measures,  President  Wilson  has  appointed 
a  number  of  prominent  engineers  in  the 
country  to  positions  in  the  army. 

One  of  the  appointments  which  will  meet 


Photo  from  Press  Illustrating  Service. 
Prof.  Miinsterberg  Claimed  to  Be  Able  to  Select  the  "Best"  Ship 
Captains,  Locomotive  Engineers,  Aviators,  Etc. — All  by  Psychology. 
Here  We  See  the  "Psychometer"  Being  Used  to  Test  the  Mental 
Alertness  of  San  Francisco  Factory  Employees.    The  World  Do  Move. 

with  the  most  hearty  approval  of  the  elec- 
trical engineering  profession  is  that  of 
Paul  M.  Lincoln,  Commercial  Engineer  of 
the  Westinghouse  Electric  &  Mfg.  Com- 
pany, as  Captain  of  the  Engineer's  Corps 
in  the  U.  S.  Army. 

Announcement  has  just  been  made  of 
this  appointment  together  with  a  number  of 
other  prominent  engineers. 

Mr.  Lincoln  graduated  from  Ohio  State 
University  in  1892,  and  has  for  24  years 
been  associated  with  the  Westinghouse 
Electric  &  Mfg.  Company.  He  is  a  Past 
President   of   the   American   Institute  of 


PROMINENT 
ELECTRICAL  EN- 
GINEER BECOMES  Here  We  See  a  Portable  "Productograph."    Connected  to  Each 
ARMY  MAN  Machine  It  Enables  the  Young  Lady  in  the  Foreground  to  Readily 

.  .  ,    *  .  Keep  an  Exact  Record  of  Each  Employee's  Output. 

Appreciating  the  im- 
portance   of    securing  Electrical  Engineers,  and  has  always  taken 
the  ability  and  training  of  the  engineers  of     an  active  interest  in  the  work  of  this  as- 
the  country   for  use  in  national  defense  sociation. 


94 


THE  ELECTRICAL  EXPERIMENTER 


June,  1917 


SOUND   RELEASES  TOY  DOG 
FROM  ITS  KENNEL. 

A  very  interesting  toy  has  recently  been 
introduced  in  the  toy  market  and  which 
is  herewith  illustrated.  A  similar  toy  was 
described  in  our  June,  1916,  issue,  but  the 
present  one  is  of  a  simpler  construction. 
The  "Wireless  Pup,"  as  it  is  called,  is 


Two  Views  of  New  "Wireless  Pup"  That  Springs  Out 
of  His  Kennel  at  the  Sound  of  a  Whistle,  the  Voice,  or 
the    Clap    of    the  Hands. 


shown  in  Fig.  1 ;  this  shows  the  dog  stand- 
ing outside  of  his  kennel.  The  sensitive 
circuit-breaker  and  other  apparatus  are  all 
placed  within  the  kennel.  This  interesting 
and  most  amusing  toy  was  originated  and 
perfected  by  Mr.  Christian  Berger,  a  promi- 
nent physicist  who  has  devoted  most  of 
his  attention  to  developing  scientific  toys. 

The  operation  of  this  toy  depends  upon 
the  opening  of  a  delicate  circuit-breaker 
by  sounding  a  whistle  or  by  the  produc- 
tion of  any  other  sound.  This  circuit- 
breaker  is  connected  in  series  with  a  bat- 
tery and  electro-magnet,  which  acts  upon 
a  flat  metallic  disc.  This  disc  or  plate  is 
so  arranged  that  when  it  is  released  by 
the  electro-magnet,  it  will  strike  the  dog, 
pushing  him  out  of  the  kennel.  The  elec- 
trical circuit  is  only  made  when  the  flat 
disc  is  prest  against  the  core  of  the  mag- 
net, which  holds  the  same  to  itself  until 
the  circuit-breaker  is  excited  by  sound 
waves. 

A  detail  photograph  showing  the  various 
parts  used  in  making  up  this  toy  is  given 
at  Fig.  2.  The  holding  electro-magnet  is 
seen  at  the  left  and  consists  of  a  core 
5^8-inch  in  length  and  ^-inch  hi  diameter; 
two  insulated  end  pieces  are  placed  on 
each  end  and  the  coil  is  wound  with  No. 
30  B.  &  S.  enameled  wire.  The  complete 
magnet  is  mounted  on  an  iron  frame,  as 
shown.  The  small  projection  on  top  of 
the  magnet  is  used  to  strengthen  the  mag- 
netic pull  of  the  electro-magnet.  The  re- 
lease or  discharge  disc  is  fastened  to  this 
frame  in  such  a  way  as  to  •  permit  the 
disc  to  spring  forward  when  released  by 
the  electro-magnet.  The  complete  arrange- 
ment is  then  mounted  on  a  wooden  base. 

The  sound  operated  circuit-breaker  is 
seen  on  the  right.  This  consists  of  a 
rectangular  metal  box  A,  in  which  the  sen- 
sitive parts  are  placed.  The  horizontal 
lever  B  is  made  from  a  No.  18  bare  wire, 
bent  as  shown ;  the  ends  are  pivoted  on  a 


block  of  wood,  the  dimensions  of  which 
are  those  of  the  interior  of  the  metal  case. 
The  lower  part  of  the  lever  B,  should 
touch  lightly  the  metal  surface  of  the  case 
A,  at  point  C.  Of  course  this  must  be 
within  the  case.  The  complete  circuit- 
breaker  is  placed  behind  the  electro-mag- 
net frame,  as  noted  in  the  assembled  ap- 
paratus (center).  Two  sheets  of  metal  are 
fastened  to  the  base  to  form  a  sound  col- 
lector. 

The  connections  of  the  toy  "pup"  is  very 
simple,  and  is  made  as  follows :  One  termi- 
nal from  the  electro-magnet  is  linked  with 
the  metal  case  of  the  circuit-breaker.  The 
lever  of  the  latter  is  terminated  in  a  small 
flashlight  battery  and  the  opposite  side  of 
the  battery  is  connected  to  the  second  lead 
from  the  magnet.  When  the  "pup"  is 
pushed  into  the  kennel  and  against  the 
tension  of  the  spring  disc,  it  is  held  by 
the  energized  electro-magnet.  Then  by 
making  a  sound 
such  as  by 
blowing  a 
whistle,  the  cir- 
c  u  i  t  -  breaker 
will  be  spurred 
up,  thus  open- 
ing m  o  m  e  n  - 
tarily  the  cir- 
cuit which  re- 
leases  the 
spring  disc, 
bouncing  Mr. 
"Fido"  out  of 
the  kennel. 

A  trap  drum- 
mer has  dis- 
covered that 
electric  lights 
i  n  s  t  a  1 1  ed  in- 
side his  drums 
keep  the  mois- 
ture out  and  makes  the  drumheads  tight. 


AN  ELECTRIC  SELF-WAVING 
FLAG. 

One  of  the  most  talked  of  features  at 
the  Electric  Railway  Convention  at  Atlan- 


St.  Patrick's  Cathedral  of  Norwich, 
Conn.,  is  lighted  with  six  electric  projec- 
tor units,  which  bring  out  the  chancel  arch 
and  altar  in  beautiful  relief. 


utton*! 

"Speakin'  o'  buttons,"  said  Uncle  Zeke,  * 
Shifting  his  quid  to  the  other  cheek, 
"Speakin'  o'  buttons,  I  want  to  say, 
There's  the  beatenest  kind,  down  New  York 

way ; 

'Twaz  in  one  o'  them  big  hotels,  by  jing, 
That  melts  your  dollars  like  snow  in  spring, 
That  I  see  them  buttons,  along  the  wall, 
Right  in  a  bunch ;  mebbee  six  in  all. 
'Twas  gittin'  too  dark  to  see  outdoors, 
An'  I  got  to  foolin'  with  them  because 
There  wuzn't  much  else  fer  me  to  do, 

i  ,         When — Jiminy  crick - 
ets ;  before  I  knew, 
^  -_  I  thought  I  had  sot 
_  "       ®  0    ^     the  house  afire, 
"    //'/'^>Nv    And  I  yelled  as  loud  as 
/  /  |  V  V  \     our         town  crier, 
Till  the   folks  came 
runnin',  lickettycut! 
I  told  them  what  wuz 

the  matter,  but 
They  didn't  do  nothin' 

but  laffe  an'  joke, 
'Bout  that  dad  blamed 
button    I    tried  to 
poke, 

Then  they  showed  me 
just  how  it  worked, 
an'  gee ! 

'Twas  the  cutest  thing  I  ever  see. 
Why,  it  made  a  blaze  like  a  bonfire  done! 
They  said  'twuz  invented  by  Eddy's  son; 
I  don't  know  just  who  Ed  is,  but  say, 
His  son  is  the  feller  that  gits  my  pay!" 

By  Pauline  Frances  Camp. 


This  Flag  Always  Waves,  Whether  There  Is 
a  Breeze  or  Not.  A  Motor-driven  Blower 
Pumps  a  Strong  Draft  of  Air  Up  Thru  the 
Hollow  Mast,  Which  Accounts  for  the  Mys- 
terious Effect  Obtained. 


tic  City,  N.  J.,  was  a  waving  flag  which 
fluttered  from  a  27-foot  flagstaff  in  front 
of  the  General  Electric  Company's  booth 
inside  the  spacious  convention  hall.  Not  a 
breath  of  air  was  stirring,  yet  the  flag 
stood  out  on  the  pole  as  if  a  thirty-mile 
gale  was  blowing.  The  flag  pole  was  of 
ordinary  dimension  and  there  was  nothing 
visible  to  betray  the  source  of  the  breeze. 
The  base  of  the  pole  was  surrounded  with 
banked  palms.  It  was  only  when  visitors 
got  very  close  to  it  that  the  scarcely  audible 
hum  of  a  motor  gave  a  clue  to  the  source 
of  the  breeze. 

The  whole  device  is  really  quite  simple 
in  construction  and  easily  explained,  for  the 
flagpole  is  a  metal  tube  and  an  electric 
blower  at  the  base  shoots  a  strong  current 
of  air  thru  the  flagstaff.  The  air  escapes 
thru  perforations  in  the  top  of  the  flagpole 
and  imparts  a  waving  motion  to  the  flag. 


PROCESS    FOR    DRAWING  LAMP 
FILAMENTS. 

A  process  for  cold-drawn  metallic  fila- 
ments has  recently  been  patented  by  Mr. 
K.  Nishimoto,  of  Tokyo.  Forming  at  first 
a  consolidated  stick  of  mixture  of  tung- 
sten and  a  small  proportion  of  thorium, 
an  alloy  is  obtained  by  uniformly  heating 
the  mixture  at  a  sintering  temperature  and 
then  gradually  keeping  its  temperature  at 
dull  red  heat.  The  consolidated  stick  is 
then  subjected  to  repeated  hammering  or 
rolling  until  it  becomes  so  ductile  that  it 
may  be  hammered  into  bars,  rolled  into 
sheets  or  drawn  thru  dies  into  wires,  much 
like  the  metals  which  are  commonly  treated 
in  this  manner  at  ordinary  temperature. 


June,  1917 


THE   ELECTRICAL  EXPERIMENTER 


95 


Powerful  Hydro  -  Electric  Salvage  Apparatus  to  Raise 


Sunken  Ships 

By  H.  Winfield  Secor,  Assoc.  A 


POSSIBLY  more  than  one  enterpris- 
ing inventor  of  to-day  has  conjec- 
tured on  the  problem  of  raising 
some,  if  not  all,  of  the  hundreds  of 
torpedoed  steamers  which  lie  scat- 
tered along  the  European  coast  in  compara- 
tively shallow  water,  not  to  mention  the" 
many  sunken  ships  lying  within  the  coast 
boundaries  of  our  own  country.  It  is  not 
often  that  we  hear  of  a  sunken  ship  being 
floated  and  brought 
into  dry-dock  for 
the  reason  that  the 
cost  of  performing 
such  an  engineering 
feat  is  generally 
prohibitive,  and 
also  in  many  in- 
stances, the  prob- 
lem of  raising  the 
sunken  vessel  at  all 
has  practically  been 
beyond  solution. 

Now  comes  an 
American  inventor, 
of  Swedish  birth, 
one  Mr.  Carl  Lin- 
quist  of  New  York, 
and  formerly  of  the 
Swedish  Navy,  who 
has  devised  a  re- 
markable new 
scheme  for  raising 
sunken  ships  of  no 
matter  what  size,  as 
long  as  they  do  not 
lie  in  too  great  a 
depth  of  water,  and 
which  idea  he  in- 
tends commercializ- 
ing at  an  early  date. 

It  goes  without 
saying  that  if  Mr. 
Linquist's  idea,  as 
outlined  herewith, 
proves  feasible  and 
successful,  that  he 
will  find  plenty  of 
work  for  several  years  to  come. 

The  inventor's  idea  involves  the  use  of 
two  or  more  telescopic  cylinders  or  cham- 
bers as  shown  in  the  accompanying  illustra- 
tion, which  are  attached  thru  massive  uni- 
versal joints  at  their  bases  to  the  large 
horizontal  submerging  chambers  or  "feet" 
which  rest  on  the  bed  of  the  ocean  or  lake. 
In  the  first  place,  it  is  of  course  paramount 
that  the  exact  location  of  the  sunken  vessel 
be  known.  Having  this  information,  the 
salvage  expedition  sets  out  from  the  near- 
est port  with  the  necessary  number  of  these 
large  collapsible  cylinders  with  their  at- 
tached base  members  ( or  "Forts"  as  their 
inventor  calls  them).  The  vertical  cylin- 
ders shown  lie  horizontally,  and  as  do  also 
the  base  members,  which  are  made  to  float, 
and  the  vertical  and  horizontal  sections 
double  up  like  a  jack-knife,  permitting  the 
several  units  of  this  equipment  to  be  towed 
by  tug  boats  to  the  scene  of  the  wreck. 

The  present  plans  of  the  inventor  con- 
sider that  salvage  operations  may  be  suc- 
cessfully carried  on  for  any  size  vessel  in 
depths  of  water  up  to  three  hundred  feet, 
and  where  necessary  four  to  eight  or  even 
more  of  the  raising  cylinders  are  employed, 
placing  an  equal  number  of  them  on  each 
side  of  the  sunken  ship. 

Supposing  that  several  units  of  the  sal- 
vage equipment  are  ready  and  floated  to 


I.  E.  E. 


the  position  where  they  are  to  be  used,  the 
engineers  then  proceed  to  fill  the  base  mem- 
ber with  water  causing  it  to  sink.  As  it 
does  so,  the  upright  cylinder  naturally  as- 
sumes a  vertical  position,  and  moreover  the 
base  member  obtains  a  very  powerful  hold 
on  the  bed  of  the  ocean  or  harbor  by  "sand- 
suction,"  besides  the  heavy  water  pressure 
bearing  down  on  its  outer  surface.  A  num- 
ber of  strong  cables  are  let  down  in  the 


After  the  War  There  Will  Be  Thousands  of  Vessels  Lying  on  the  Oceans'  Beds.  If  Only  a 
Fraction  of  These  Can  Be  Floated  and  Repaired,  Think  What  It  Will  Mean  to  Commerce. 
A  New  Invention  Intended  to  Accomplish  This  Purpose  Is  Illustrated  Here  and  Involves 
the  Use  of  Two  or  More  Powerful  Cylinders  Which,  as  They  Are  Emptied  of  Water  and 
Made  More  and   More   Buoyant,   Finally  Exert  Sufficient   Upward   Pull   on  the  Cables  to 

Lift  the  Vessel. 


water,  and  with  the  aid  of  an  operator  in- 
side the  inner  pontoon  who  directs  the 
work,  these  cables  are  swept  under  the  hull 
of  the  sunken  vessel.  When  all  of  the 
cables  have  been  properly  placed,  the  en- 
gineers are  ready  to  begin  operations  for 
raising  the  wreck.  Here  is  where  the  re- 
markable genius  of  Mr.  Linquist  comes  into 
play,  for  he  does  not  attempt  to  raise  the 
ship  by  means  of  steam  or  any  other  form 
of  engine.  He  has  called  upon  Dame  Na- 
ture herself  to  furnish  the  wherewithal  to 
raise  any  ship,  no  matter  what  the  size.  In 
brief,  what  he  does  is  this  : — 

The  upper  telescopic  and  movable  cylin- 
ders rising  within  the  vertical  floating 
chambers  and  guides,  they  are  allowed  to 
fill  with  water  from  the  ocean  itself,  and 
as  will  be  seen  these  will  then  sink  to  any 
required  depth.  When  they  have  submerged 
until  their  upper  structure  is  just  above  the 
water,  the  valves  are  closed,  and  by  means 
of  powerful  electric  pumps  (in  case  the 
operations  take  place  a  considerable  dis- 
tance from  shore,  gasoline  engine-driven 
pumps  are  available),  the  water  within  the 
movable  upper  cylinders  is  rapidly  pumped 
out.  But  a  moment's  reflection  is  required 
to  at  once  see  that  these  upper  cylinders 
will  naturally  become  steadily  more  and 
more  buoyant,  and  providing  they  are  built 
of  the  proper  size  for  the  work  in  hand, 


they  will  exert  a  tremendous  lifting  power 
of  thousands  of  tons.  After  these  cylin- 
ders have  gone  up  a  suitable  distance  the 
lines  are  caught  by  the  stationary  vertical 
member  and  the  ship  is  thus  held  while  the 
floating  cylinders  re-fill  and  take  a  new 
bite ;  the  same  operation  is  then  repeated  to 
the  surface. 

Mr.  Linquist  intends  building  these  cylin- 
ders, not  of  steel  but  of  narrow  strips  of 
wood  several  inches 
thick,  or  steel  may 
be  used  in  certain 
cases.  The  wood 
strips  are  tongued 
and  grooved  and 
caulked  and  are  held 
in  shape  by  steel 
bands.  The  pressure 
of  the  water  on  the 
outside  of  the  cylin- 
ders will  in  conse- 
quence tend  to  al- 
ways tighten  them, 
as  becomes  evident. 

The  inventor  has 
broached  and  dem- 
onstrated by  means 
of  models,  his 
unique  idea  to  a 
large  number  of 
sea-going  men,  in- 
cluding commanders 
of  salvage  squad- 
rons, and  also  to  a 
number  of  naval 
men,  and  has  re- 
ceived  unqualified 
recommenda- 
tions  from  these 
men,  who  should  be 
qualified  to  judge  as 
to  the  efficiency  or 
inefficiency  of  such 
a  device  if  anyone 
could.  Not  only  is 
this  idea  of  consid- 
erable promise  and 


utilification  in  salvaging  sunken  vessels  in 
times  of  peace,  but  it  possesses  according 
to  Mr.  Linquist,  several  valuable  naval  fea- 
tures. For  one  thing  he  has  suggested  that 
one  of  these  hydrostatic  units  would  prove 
very  efficacious  in  the  role  of  a  "Submarine 
Base,"  the  outfit  being  anchored  several 
hundred  miles  from  shore  stations  if  de- 
sirable. Also  they  would  serve  as  a  resting 
place  for  the  crew. 

The  inner  cylinder  would  have  a  large 
capacity  for  the  storage  of  oil  and  gaso- 
line for  submarines,  and  in  the  event  of 
being  sighted  by  a  hostile  war  vessel,  the 
upper  cylinder  and  super-structure  could  be 
submerged  so  as  to  be  invisible,  and  the  in- 
ventor claims  that  no  force,  even  the  ocean 
itself,  cannot  budge  his  suction  foot  mem- 
ber an  inch,  once  it  has  got  its  grip  on  the 
bed  of  the  ocean  by  natural  "sand-suction," 
and  besides  most  of  the  floating  membei 
lies  in  calm  water,  the  action  of  the  waves 
not  reaching  very  deep.  A  means  is  pro- 
vided for  releasing  this  all-powerful  grip 
upon  the  ocean-bed  when  it  becomes  de- 
sirable to  move  the  unit  to  some  other  lo- 
cation. .U.  S.  Naval  Officers  have  been 
favorably  imprest  with  this  idea. 

In  closing,  it  is  interesting  to  note  that 
another  valuable  possibility  of  this  device 
is  that  of  releasing  stranded  vessels  which 
(Continued  on  page  144) 


AMONG  the  hundreds  of  new  devices  and  appliances  publisht  monthly  in  The  Electrical  Experimenter,  there  are  several,  as 
a  rule,  which  interest  you.    Full  information  on  these  subjects,  as  well  as  the  name  of  the  manufacturer,  will  be  gladly 
furnisht  to  you,  free  of  charge,  by  addressing  our  Technical  Information  Bureau. 


96 


THE   ELECTRICAL  EXPERIMENTER 


June,  1917 


ELECTRICITY  NOW  ROCKS  THE 
CRADLE. 

"The  hand  that  rocks  the  cradle,  rules 
the  world" — runs  an  age  old  proverb,  and, 
albeit,  one  that  embodies  more  truth  than 
fiction  nowadays,  perhaps,  when  we  have 


A  Chicago  Genius  Has  Evolved  a  Clever  Combination — a  Baby 
Carriage  Plus  an  Electric  Motor  and  Part  of  a  Small  Grinder 
Reduction  Gear.     Result — No  More  Pushing  the  Baby  Carriage 
Back  and  Forth.    We'll  Bet  His  Wife  Is  a  Suffragette! 


and  sawed  a  slot  into  it  for  a  distance  of  a 
foot  at  the  other  end,  this  slot  passing  thru 
a  hole  bored  in  it  of  the  size  of  the  wood 
handle  on  the  grinding  mechanism,  which  is 
inserted  thru  the  hole  and  then  the  two 
parts  of  the  connecting  rod  brought  to- 
gether upon  it  by  means  of  a  little  bolt. 

Only  a  minute  is  re- 
quired to  trundle  the 
little  wooden  frame 
to  any  place  in  the 
house,  one  end  being 
provided  with  little 
casters,  also  shown  in 
the  picture.  The  mo- 
tor can  be  attached  to 
any  lamp  socket  by 
means  of  a  flexible 
attachment  cord,  and 
in  this  circuit  near 
one  of  the  binding 
posts  on  the  motor 
Mr.  Joleen  has  in- 
serted a  small  push- 
button switch  for 
starting  and  stopping 
the  motor.  When  the 
carriage  is  set  on  its 
yHP1  little  track  the  con- 

kSSfUBZ^^k.  necting  rod  can  be  in- 

v^fH^^  stantaneously  con- 

nected by  simply  lay- 
ing it  on  the  bar  so 
that  the  slot  engages 
the  latter,  and  the  ap- 
paratus is  ready  'to 
work.  Who  will  be 
so  kind  as  to  invent 
an  electric  bottle 
feeder?  Next! 


the  suffrage  party  to  conjure  with.  But 
the  "stiffs"  will  have  to  look  to  their  lau- 
rels, for  here  is  an  electric  motor  that  rocks 
the  cradle.  Yes,  and  it  doesn't  object  to 
twins  or  triplets.  "Come  one,  come  all,"  is 
its  motto. 

This  device  not  only  will  rock  the  cradle 
but  will  trundle  a  baby  carriage  back  and 
forth  on  a  little  track,  with  a  gentle,  sooth- 
ing motion  which  may  be  better  than  the 
traditional  cradle  rocking  movements.  The 
device  was  made  for  private  use  by  Mr. 
Nels  Joleen,  of  Chicago. 

Mr.  Joleen's  little  girl  required  so  much 
of  Mrs.  Joleen's  time  that  the  resourceful 
father  decided  that  as  long  as  the  gentle 
pushing  to  and  fro  of  the  baby  carriage 
seemed  to  be  a  sovereign  pacifier  on  all 
occasions,  he  would  provide  something 
which  would  perform  the  mechanical  work, 
leaving  the  mother  free  to  go  about  her 
other  duties. 

Accordingly,  Mr.  Joleen  made  the  little 
wooden  frame,  shown  under  the  wheels  of 
the  carriage ;  attached  thereto  a  grinding 
wheel  designed  to  be  operated  by  hand, 
something  which  he  had  in  the  house  for 
sharpening  tools ;  and  then  attached  a  small 
motor  of  the  kind  which  was  once  used  as 
a  sewing  machine  motor,  accomplishing  the 
connection  by  means  of  a  belt  from  a  very 
small  pulley  on  the  axle  to  the  perifery  of 
the  grinding  wheel.  The  driving  pulley  had 
to  be  made  so  small  that  he  simply  cut  a 
short  section  of  a  broom  handle,  bored  a 
hole  thru  the  center,  and  fastened  it  on 
with  a  small  set-screw.  The  gearing  in  the 
grinding  wheel  mechanism,  originally  in- 
tended to  speed  up  the  grinding  wheel  with 
reference  to  the  number  of  revolutions  per- 
formed by  the  handle,  now  works  just  the 
other  way  to  all  intents  and  purposes,  as 
the  speed  of  the  motor  must  be  reduced  to 
the  slow  circular  movement  desired. 

In  order  to  transmit  this  motion  and  at 
the  same  time  translate  it  into  a  back  and 
forth  movement  Mr.  Joleen  then  took  a 
small  piece  of  wood  about  three  feet  long, 
notched  it  at  one  end  where  it  rests  over  a 
brace  underneath  the  body  of  the  carriage, 


SEWING  MACHINE  PLUS  MOTOR, 
SAVES  LABOR. 

The  sewing  machine  was  one  of  the  first 
household  appliances  to  be  equipt  with  an 


This  Electric  Sewing  Machine  Motor  Drops 
Out  of  Sight  with  the  Head  and  Drives  Very 
Efficiently    Owing    to    Its   Spring  Base 
Mounting, 

electric  motor.  The  first  motors  employed 
were  just  the  ordinary  type,  but  later  de- 
signs have  resulted  in  the  development  of 
a  motor  having  necessary  speed  control  for 
use  solely  on  sewing  machines,  and  the  effi- 
ciency and  operating  features  of  such 
motors  have  been  greatly  improved. 

The  latest  and  most  desirable  features 
are  to  be  found  in  the  special  motor  shown 
in  the  accompanying  illustration. 

This  type  can  be  readily  attached  to  any 
make  of  stationary  or  drop-head  sewing 
machine,  new  or  old,  with  the  exception  of 
a  few  obsolete  models.  When  not  in  use 
the  motor,  if  mounted  on  a  stationary  head 
machine,  can  be  pushed  back  out  of  the 
way  and  the  cover  put  on,  or  dropt  with 
the  head  if  used  on  modern  types  of  drop- 


head  machines.  When  desired,  however, 
the  motor  can  be  removed  readily  by 
loosening  one  thumb  screw,  as  it  is  light 
and  portable. 

The  speed  regulator  is  slipt  on  the 
treadle  and  held  by  a  spring,  making  the 
mounting  exceedingly  simple.  The  operat- 
ing chain  is  attached  to  the  metal  frame- 
work directly  above  the  controller  and 
pulled  taut. 

The  regulator  is  light  and  substantial. 
The  case  is  made  of  prest  steel  and  the 
principle  of  operation  is  entirely  new. 
When  there  is  no  pressure  on  the  treadle 
the  circuit  is  open.  With  a  slight  pressure 
on  the  treadle  a  contact  is  made  and  as  a 
greater  pressure  is  applied  the  resistance 
is  cut  out  turn  by  turn.  By  varying  the 
pressure,  one  stitch,  or  several  hundred 
stitches  a  minute  can  be  taken.  There  are 
approximately  100  steps  in  the  controller, 
giving  a  corresponding  number  of  speeds. 

When  folding  up  the  machine  it  is  only 
necessary  to  loosen  the  belt,  disconnect  the 
plug,  and  swing  the  motor  around  under 
the  head.  Felt  pads  underneath  the  base 
prevent  the  motor  from  scratching  the  fin- 
ish of  the  machine. 

The  motor  itself  is  out  of  the  way  when 
operating.  This  leaves  both  sides  of  the 
machine  table  clear  so  that  the  operator 
can  use  this  space  for  sewing  material. 

The  outfit,  which  is  compact  and  light, 
consists  of  a  small  motor  which  operates 
on  either  alternating  or  direct  current, 
mounted  on  a  nickel-plated  base,  a  speed 
regulator  with  operating  chain  and  ten  feet 
of  cord  and  plug,  and  a  round  leather  belt. 
The  weight,  including  the  speed  regulator, 
is  only  7  pounds. 

The  cost  of  operating  this  motor  is  so 
small  as  to  be  almost  negligible.  At  10 
cents  per  kilowatt  hour,  it  costs  less  than 
one  cent  an  hour  or  less  than  it  takes  to 
run  the  ordinary  incandescent  lamp. 


THE  ELECTRIC  TEA  KETTLE  IS 
HERE. 

The  recognized  convenience  and  growing 
popularity  of  heating  small  quantities  of 
water  by  electricity  has  prompted  the  de- 
velopment of  the  electric  tea  kettle  illus- 
trated. 

The  successful  operation  of  an  electric 
tea  kettle  depends  largely  upon  the  type  of 
heating  element — method  of  application  of 
heat,  etc.  The  heating  element  here  used 
is  of  the  submerged  type,  located  on  the 
bottom  of  the  tea  kettle  and  when  in  use 
is  entirely  surrounded  by  water.  Thus  all 
heat  generated  is  efficiently  utilized. 

The  tea  kettle  has  a  capacity  of  2^  pints, 
is  made  of  drawn  copper,  spun  into  shape; 
spout  of  white  metal ;  has  bail  handle,  sides 
of  which  are  steel,  grip  made  of  ebonized 


Here  We  Have  the  Electric  Tea  Ket- 
tle.    Hot  Water  When  You   Want  It 
and  Where  You  Want  It  Is  Now  an 
Actual  Fact. 


wood  comfortably  shaped  for  convenient 
pouring.  The  lid  has  no  hinge  to  come  off 
—locks  on  securely.  The  knob  forms  an 
integral  part  of  the  metal  lid. 


June,  1917 


THE  ELECTRICAL  EXPERIMENTER 


97 


THE  PROPERTIES  AND  COMMER- 
CIAL APPLICATIONS  OF 
SELENIUM. 

By  W.  F.  Alder. 

Selenium  was  discovered  by  the  Swedish 
scientist,  Berzelius,  in  1817  as  a  by-product 
of  the  distillation  of  sulfuric  acid  from 
iron  pyrites.  It  has  an  atomic  weight  of 
79.5  specific  gravity  in  its  electrical  con- 
ducting form  of  4,788,  its  va- 
por sp.  gr.,  at  2,588°F.,  being 
5.68. 

Selenium,  like  sulfur,  with 
which  it  is  isomorphous,  ex- 
ists in  different  allotropic 
forms,  three  of  which  are  as 
follows : 

(1)  Amorphous  Selenium  is 
formed  as  a  finely  divided 
brick-red  powder,  when  a  so- 
lution of  selenous  acid  is  pre- 
cipitated by  sulfur  dioxid  gas, 
or  when  the  acid  is  reduced  by 
suitable  agents.  Amorphous 
selenium  has  a  sp.#  gr.  of  4.26 
and  is  soluble  in"  carbon  di- 
sulfide. 

(2)  (a)  Semi-colloidal  red 
amorphous     Selenium  is 

formed  when  solutions  of  dextrose  and 
selenous  or  selenic  acid  are  gently  heated 
together.  At  100°C.  it  is  partially  trans- 
formed into  ordinary  black  Selenium. 

(b)  Colloidal  Selenium  can  be  obtained 
in  a  blood-red  solution  by  an  aqueous  solu- 
tion of  the  red  precipitate  obtained  by  ihe 
reduction  of  Se  02. 

(3)  Vitreous  Selenium  is  formed  when 
the  amorphous  variety  is  heated  to  218° 
C.  and  then  suddenly  cooled  when  it  forms 
a  brittle,  black,  glassy  mass,  soluble  in  car- 
bon disulfide  having  a  sp.  gr.  of  4.28. 

All  three  of  the  above  forms  have  so 
high  an  electrical  resistance  that  they  may 
be  regarded  as  non-conductors. 

The  Selenium  as  used  in  the  electrical 
arts  belongs  to  still  another  modification, 
viz.,  the  crystalline  or  metallics  state ; 
metallic  selenium  is  obtained  when  the 
melted  vitreous  variety  is  cooled  to  210° 
C,  and  then  maintained  at  that  tempera- 
ture for  some  time.  , 

The  gray  crystalline  modification  which 
makes  possible  the  selenium  cell  occurs  in 
two  forms,  vi7 

(1)  Round  gran- 
ular crystals,  stable 
at  140°C,  an  insu- 
lator in  the  dark 
and  not  very  sensi- 
tive to  changes  in 
light  intensity. 

(2)  Which  is 
readily  formed 
when  the  above 
granular  form  is 
heated  to  200° C.  In 
this  form  it  is  a  rel- 
atively good  con- 
ductor. It  will, 
however,  instantly 
respond  to  succeed- 
ing exposures.  The 
general  belief,  also 
erroneous,  seems 
to  be  that  the  short- 
est wave  lengths, 
i.e.,  the  violet,  are 
the  ones  which  have 
t  h  e  most  pro- 
nounced effect  upon 
the  conductivity  of 
Selenium,  but  ex- 
haustive research 

has  proven  that  the  waves  having  the  great- 
est activity  for  increasing  the  conductivity 
have  a  length  of  over  5,000  units. 

The  writer  encountered  innumerable 
difficulties  which  were,  however,  overcome 
in  the  type  of  cell  illustrated  herewith. 


Electro-Deposited  Mirrors  Now  Used  for 
Photographic  Work 


IN  splitting  the  light  from  a  certain 
source,  the  problem  of  dividing  the 
rays  in  definite  portions  may  strike 
one  at  first  thought  as  an  exceedingly 
difficult  task.  In  certain  kinds  of  pho- 
tographic and  optical  work,  however,  it  is 


voltage,  however,  is  very  high  and  is  stept 
up  by  a  transformer  from  a  value  of  156 
volts  to  5,000  volts. 

As  soon  as  the  current  is  turned  on  a 
pink  glow  is  noticeable  in  the  jar.  Just 
above  the  thin  metal  cathode,  however, 
there  is  a  certain  dark  region  which  is 
called  the  Crooke's  dark  space.  The  action 
of  the  current  causes  minute  particles  of 
metal  to  leave  the  cathode  and  to  be  de- 
posited on  the  glass  plate  which  is  placed 
just  at  the  edge  of  the  Crooke's  dark  space, 
where  the  metal  is  most  cohesively  depos- 


Fig.  3  (At  Left).  Jar  for  Making  11-inch  Partly 
Transparent  Mirrors.  The  Cathode  Is  at  the  Bottom 
and  Consists  of  a  Thin  Sheet  of  Gold  or  Platinum- 
iridium  Alloy.  The  Glass  Plate  to  be  Coated  Is  in  a 
Plane  Parallel  to  the  Cathode. 

Fig.  1  (Below).  Arrangement  of  Apparatus  for  Electro- 
plating Partly  Transparent  Mirrors  in  a  Vacuum,  the 
Smaller  Jar  Being  in  Operation. 


Selenium   Cell  in 
Vacuum. 


very  essential  to  divide  the  rays  in  such  a 
manner  that  one  portion  of  the  light  will 
go  in  one  direction  and  the  remaining  por- 
tion in  one  or  more  other  directions.  Part- 
ly transparent  mirrors  are  used  for  the  pur- 
pose, and  in  order  that  the  precise  division 
of  light  may  be  known  beforehand,  the 
thickness  of  the  thin  layer  of  metal  which 
is  deposited  on  a  plate  of  glass  to  form  the 
mirror  must  be  exactly  known. 

In  Fig.  1  is  shown  the  apparatus  devel- 
oped in  the  research  laboratory  of  one  of 
the  leading  camera  manufacturers  for  use 
in  making  mirrors  of  different  degrees  of 
transparencies  employed  in  certain  impor- 
tant photographic  experiments.  Two  in- 
verted glass  bell  jars  are  shown,  each  of 
which  is  connected  to  a  vacuum-pump  sys- 
tem. By  means  of  this  arrangement  the  air 
pressure  inside  the  jars  is  reduced  to  a 
scant  millimeter.  This  is  done  because  in 
a  rarefied  gas  the  passage  of  electricity 
from  the  cathode,  the  terminal  at  the  bot- 
tom of  each  jar,  to  the  anode — the  upper 
terminal,  is  greatly  facilitated.  The  ca- 
thode consists  of  a  very  thin  sheet  of  metal, 
which  usually  is  of  gold  or  an  alloy  of 
platinum  and  iridium.  A  short  distance 
above  this  sheet  of  metal  in  a  plane  paral- 
lel to  it ;  the  glass  plate  to  be  coated  is 
placed  on  glass  pillars  as  shown. 

The  larger  jar  is  16  inches  in  diameter 
and  11  inches  high  and  is  used  for  coating 
mirrors  11  inches  square.  With  the  air  ex- 
hausted the  atmospheric  pressure  on  this 
jar  (about  15  pounds  per  square  inch) 
mounts  up  to  approximately  five  tons. 
The  current  is  measured  in  thou- 
sandths of  an  ampere  (milliamperes).  The 


ited.  With  the  current  constant  it  is  only 
necessary  to  record  the  time  of  operation ; 
the  amount  of  metal  deposited  can  then  be 
easily  determined,  since  it  will,  according 
to  Faraday's  law,  be  proportional  to  the 
time  and  current. 

In  Fig.  2  is  shown  a  set  of  interesting 
curves  obtained  in  a  typical  run  with  a 


M//  Amps.  -  Minute 
Fig.  2.  Curves  Showing  Reflecting  Power  at 
45  Degrees  Incidence  and  Percentage  of 
Metal  Deposited  and  Light  Transmitted  for 
Platinum-iridium  Mirror  With  Varying  Prod- 
ucts of  Time  and  Current. 

cathode  of  70  per  cent  platinum  and  30 
per  cent  iridium,  measuring  120  millimeters 
by  120  millimeters  by  0.1  millimeter.  These 
curves  show  the  reflecting  power  at  45 
degrees  incidence  and  the  percentage  of 
light  transmitted  and  metal  deposited  on  a 
unit  of  area  for  varying  products  of  cur- 
rent and  time.  It  was  found  that  a  mirror 
whose  transmission  was  equal  to  its  re- 
flection required  a  deposit  of  3.4  milli- 
grams per  square  decimeter. 
Photos  courtesy  of  Eastman  Kodak  Co. 


98 


THE  ELECTRICAL  EXPERIMENTER 


June,  1917 


A  New  Optical  Pyrometer 


The  new  pyrometer  here  shown  is  a  prac- 
tical, convenient,  and  at  the  same  time,  ac- 
curate instrument,  which  can  be  success- 
fully used  by  unskilled  workmen.  Temper- 
atures from  700°C.  upwards  are  read  di- 
rectly upon  clear,  open  scales.  Owing  to 
the  rapidity  with  which  readings  can  be 


New  English  Electrical  Tempera- 
ture Measuring  Instrument,  Based 
on  the  Comparison  of  a  Beam  of 
Monochromatic  Light  from  the 
Heated  Body  with  a  Similar  Beam 
from  an   Incandescent  Lamp. 


taken,  and  the  ease  of  sighting  upon  small 
objects,  this  pyrometer  is  particularly  suit- 
able for  research  purposes  and  in  many 
processes  in  steel,  pottery,  glass  and  other 
works.  It  has  been  developed  by  an  Eng- 
lish concern. 

The  instrument  may  be  regarded  as  a 
photometer,  in  which,  by  simply  rotating 
the  eyepiece,  a  beam  of  selected  monochro- 
matic light  from  the  hot  body  is  adjusted  to 
equal  intensity  with  a  beam  of  similar  light 
from  an  incandescent  electric  lamp.  It  is 
not  a  color-matching  instrument,  and  in 
consequence  of  the  simple  construction,  ac- 
curate readings  can  be  taken  repeatedly  by 
different  observers  with  remarkable  con- 
sistency. The  formula,  which  expresses 
the  relationship  between  the  intensity  of  the 
radiation  of  a  hot  body  and  its  temperature, 
has  been  examined  both  theoretically  and 
practically  by  many  investigators  and  has 
been  shown  to  give  results  of  great  accu- 
racy up  to  the  highest  temperatures.  The 
constants  of  this  formula  for  every  instru- 
ment are  individually  determined  at  several 
temperatures  before  calibration. 

The  general  arrangement  of  the  instru- 
ment is  shown  in  the  figure  and  includes : — 
The  pyrometer,  consisting  of  the  optical 
system,  the  electric  lamp,  the  shield  carry- 
ing the  temperature  scale  and  pointer ;  the 
teak  carrying-case  with  fittings  for  fixing 
the  pyrometer  and  standard  lamp  for  check- 
ing; 4-volt  accumulator,  ammeter  and  reg- 
ulating resistance,  complete  in  teak  case; 
the  standard  lamp  and  an  adjustable  tripod 
stand. 

The  following  is  a  brief  explanation  of 
the  construction.  Behind  the  enlarged  part 
in  the  front  of  the  pyrometer  in  which  is 
fitted  the  electric  lamp,  are  two  holes. 
Light  from  the  object  (such  as  a  furnace) 
under  observation  passes  thru  one,  and 
light  from  the  lamp  thru  the  other.  These 
beams  of  light  then  pass  thru  a  system  of 
lenses  and  prisms,  are  polarised  in  differ- 
ent planes  and  rendered  monochromatic. 
Finally  the  two  beams  of  light  pass  thru 
a  single  ocular.  The  observer  sees  an  il- 
luminated circular  field  divided  into  two 
semi-circles  One  semi-circle  is  filled  by  an 
image  of  the  hot  body  under  observation, 
while  the  other  is  uniformly  illuminated  by 
the  electric  lamp.  The  two  semi-circles  are 
brought  to  an  equal  intensity  of  illumina- 
tion by  turning  the  eyepiece  to  which  the 


scale  pointer  is  directly  attached  as  seen. 

In  this  manner  the  unknown  rays  are 
compared  with  those  of  known  intensity 
from  the  electric  lamp.  As  the  accuracy 
depends  upon  the  constancy  of  the  light 
from  the  electric  lamp,  a  small  ammeter 
and  regulating  resistance  are  fitted  in  the 


box  containing  the  accumulator  to  ensure 
that  whatever  the  voltage  of  the  battery 
may  be,  the  current  passing  thru  the  lamp 
is  constant.  To  ensure  that  the  candle- 
power  of  the  lamp  shall  remain  constant 
over  long  periods  as  the  filament  ages,  pro- 
vision is  made  for  calibrating  the  instru- 
ment from  time  to  time  against  a  stand- 
ard amyl-acetate  lamp,  and  thus  ascertain- 
ing the  correct  reading  of  the  ammeter, 
when  the  electric  lamp  is  giving  the  cor- 
rect illumination.  This  test  need  only  be 
made  at  long  intervals  and  the  standard 
lamp  need  not  be  carried  into  the  factory 
or  plant. 

The  pyrometer  is  supplied  fitted  with  one 
or  more  temperature  scales  of  any  desired 
range  from  700° C.  upwards,  but  the  fol- 
lowing standard  ranges  are  suggested  as 
suitable  for  most  practical  considerations: 
single  scale  instruments,  700-1400°C. ;  sin- 
gle scale  instruments,  900-2000°C. ;  double 
scale  instruments,  70O-14O0°C.  and  1200- 
2500°C. ;  double  scale  instruments,  900- 
2000°C.  and  140O-4000°C. 


ELECTRIC  COUCH  INDUCES 
CURRENTS  IN  THE  BODY. 

By  H.  H.  Parker 

The  electric  couch  described  in  this  ar- 
ticle makes  possible  a  simple  application  of 
the  commercial  alternating  current  in  the 
electro-therapeutical  treatment  of  insomnia, 
hardening  of  the  arteries,  nervous  dis- 
orders and  other  similar  ailments ;  a  num- 
ber of  sufferers  from  such  troubles  claim 
that  they  have  been  greatly  benefited  thru 
its  use.  While  the  apparatus  has  been  con- 
structed in  various  forms,  the  one  described 
has  the  advantages  of  simplicity,  lightness, 
neat  appearance  and  ease  of  operation,  pro- 
vision being  made  for  connection  to  any 
lighting  circuit  carrying  alternating  current 
at  110  or  220  volts  and  any  frequency. 

The  couch  itself  is  an  ordinary  wicker- 
work  affair,  to  the  bottom  of  which  are 
fastened  a  series  of  coils,  wound  upon  lam- 
inated sheet  iron  cores.  In  the  one  shown 
in  the  illustration  eight  coils  are  used,  con- 
nected in  series  for  220  volts  and  in  series- 
parallel  in  groups  of  four  in  series  when 
operating  on  110  volts.  At  a  convenient 
point  at  the  head  of  the  couch  is  placed  a 
wall  key  socket  for  cord  and  plug. 

Owing  to  the  use  of  alternating  current, 


laminated  i  on  cores  must  be  provided  for 
the  coils;  these  are  built  up  of  No.  22  gage 
iron  strips  one  and  a  half  inches  wide  by 
twenty-six  inches  long,  the  completed  core 
being  about  half  an  inch  thick.  The  strips 
are  shellacked  before  being  put  together, 
and  are  held  by  paper  insulated  rivets  in 
order  to  prevent  the  formation  of  eddy 
currents  in  the  iron  or  rivets.  After  in- 
sulating the  cores  they  are  wound  with 
two  layers  each  of  No.  20  D.C.C.  magnet 
wire,  coated  with  shellac  or  insulating  var- 
nish, wrapt  with  cotton  armature  binding 
tape  and  then  bent  to  conform  somewhat 
to  the  curve  of  the  couch  surface  when 
sagged  by  the  weight  of  a  patient  lying 
upon  it 

As  part  of  the  equipment  a  Test  Coil  is 
provided.  This  comprises  a  built-up  iron 
core  similar  to  the  others,  but  only  about 
three-quarters  of  an  inch  square  in  section. 
At  its  center  is  wound  two  layers  of  No. 
25  D.C.C.  magnet  wire  in  a  coil  about  six 
inches  long,  the  terminals  of  which  are 
carried  to  a  miniature  lamp  socket  at  the 
end  of  the  core  containirjg  a  two-and-a-half 
volt  battery  lamp.  This  wand-like  con- 
trivance is  considered  by  the  patient  an  in- 
dispensable part  of  the  outfit,  and  is  used 
to  determine  when  the  couch  is  "working.'' 
When  brought  into  the  influence  of  the 
rapidly  alternating,  magnetic  field  surround- 
ing the  coils  the  little  lamp  is  lighted,  the 
dimensions  of  its  coil  being  such  that  the 
core  may  be  laid  upon  the  couch  in  close 
proximity  to  the  coils  beneath  without 
danger  of  burning  out  the  bulb.  By  moving 
the  test  coil  away  from  and  around  the 
couch  a  visible  demonstration  of  the  strength 
and  extent  of  the  magnetic  field  is  af- 
forded. 

To  operate  the  couch  the  patient  merely 
lies  down  upon  it  and  switches  on  the  cur- 
rent. No  physical  effect  is  noticeable  be- 
yond a  slight  vibration  due  to  the  alter- 
nating current,  the  beneficial  results  ob- 
tained being  supposedly  an  effect  of  the 
rapidly  alternating  magnetic  field  surround- 
ing the  body. 

There  appears  to  be  a  difference  of 
opinion  among  medical  men  as  to  the  exact 
action  of  this  magnetic  field  upon  the  hu- 
man system,  but  in  looking  at  the  subject 
from  the  engineer's  instead  of  the  physi- 
cian's viewpoint,  the  following  theory  sug- 
gests itself :  Do  the  blood  circulatory  pas- 
sages, the  veins  and  arteries,  or  any  of  the 


Unique  Electric  Couch  Which  Passes  Power- 
ful,  Alternating    Magnetic   Fields  Thru  the 
Body. 


organs  or  other  parts,  form,  as  it  were, 
the  closed  secondary  circuit  of  a  trans- 
former, in  which  currents  are  induced 
through  the  action  of  the  magnetic  field 
produced  by  the  alternating  current  flowing 
in  the  primary  winding  of  the  coils  beneath 
the  couch? 


June,  1917  THE  ELECTRICAL  EXPERIMENTER  99 


Prof.  Bell  Receives  "Civic  Forum  Medal"  For  1917 


SIR   OLIVER  JOSEPH  LODGE. 
June,    1917,    Marks     His    66th  Birth 
Anniversary. 

One  of  the  most  profound  scientific 
workers  and  thinkers  we  have  ever  had,  is 
Sir  Oliver  Joseph  Lodge,  who  is  still  an 
active  figure  in  the  field  of  scientific  re- 
search, and  all  of  us  expect  in  the  near 
future  to  see  something  even  more  won- 
derful than  any  of  his  preceding  discoveries 
and  inventions. 

•Sir  Oliver  Joseph  Lodge  was  born  on 
June  12,  1851,  at  Penkull,  Staffordshire, 
England.  He  received  his  early  education 
in  the  Newport  Grammar  School  and  later 
he  entered  the  University  of  Coll,  London, 
where  he  specialized  in  scientific  and  mathe- 
matical research.  His  scientific  trend  was 
noticed  by  the  professors  of  different  uni- 
versities, and  after  he  had  graduated  from 
this  institution  he  was  elected  as  Profes- 
sor of  Physics  at  the  University  of  Liver- 
pool. Since  1900  he  has  been  principal  of 
the  University  of  Birmingham. 

He  has  had  many  honors  and  degrees 
conferred  upon  him  and  is  an  active  mem- 
ber of  many  of  the  leading  scientific  in- 
stitutions. Sir  Oliver  Lodge  was  presented 
with  the  honorary  degree  of  Doctor  of 
Science  from  Oxford,  Cambridge,  Victoria, 
Liverpool  and  others,  also  that  of  LL.D. 
from  St.  Andrews,  Glasgow  and  Aberlaide. 
He  was  president  of  the  Mathematical  and 
Physical  section  of  the  British  Association 
in  1891  and  President  of  the  Physical  So- 
ciety of  London.  His  most  important  work 
in  electro-physical  science  is  that  of  wire- 
less telegraphy,  in  which  he  has  introduced 
some  of  the  most  fundamental  steps  in 
commercializing  this  fascinating  art,  and 
in  fact  he  is  called  by  many  the  father  of 
wireless.  The  Lodge  coherer  was  the  first 
instrument  used  for  successfully  receiving 
radio  waves. 

He  discovered  in  1889  that  two  metal- 
lic surfaces  in  perfect,  but  not  conducting 


Sir  Oliver  Joseph  Lodge,  Famous  Eng- 
lish Physicist  and  Savant.     He  Is  Re- 
garded by  Many  as  the  Dean  of  Pres- 
ent-Day  Scientists. 


contact,  were  welded  together  when  an  elec- 
tric discharge  past  between  them,  and  later 
on  studied  the  propagation  of  electric  waves 


The  accompanying  photo  shows  the  pre- 
sentation of  the  "Civic  Forum  Medal"  for 
1917,  to  Dr.  Alexander  Graham  Bell,  the 


inventor  of  the  telephone.  Those  in  the  pic- 
ture from  left  to  right  are  :  John  J.  Carty, 
chief  engineer  of  the  American  Telephone 
and  Telegraph  Company ;  Union  N.  Bethell, 
president  of  the  New  York  Telephone 
Company  and  senior  vice-president  of  the 
American  Telephone  and  Telegraph  Com- 
pany; Dr.  John  H.  Finley,  (presenter  of  the 
medal)  ;  Alexander  Graham  Bell,  inventor 
of  the  telephone,  and  Thomas  A.  Watson, 
associate  of  Dr.  Bell,  maker  of  the  first 
telephone  instrument  and  receiver  of  the 
first  telephone  message.  On  the  table  are 
the  first  instruments  used  by  Dr.  Bell. 

On  March  21,  in  Carnegie  Hall,  New 
York,  Dr.  Alexander  Graham  Bell,  was  for- 
mally presented  with  the  Civic  Forum 
Medal   of  honor   for  distinguished  public 


along  wires.  He  thus  came  into  close 
contact  with  the  researches  of  Hertz  on 
the  creation  of  electromagnetic  waves  in 
free  space,  and  this  work  he  both  expounded 
and  extended. 

His  interest  in  these  matters  was,  how- 
ever, scientific  rather  than  technical,  and 
he  himself  has  admitted  that  before  the 
matter  had  received  attention  from  others 
it  had  not  occurred  to  him  to  suggest 
the  employment  of  Hertzian  waves  for 
practical  telegraphic  purposes.  In  the 
course  of  his  scientific  work  he  had  di- 
rected much  attention  to  the  phenomena 
of  electrical  resonance.  Hence,  when  it 
had  been  indicated  that  the  chief  prac- 
tical importance  of  Hertzian  waves  might 
be  in  their  application  to  space-telegraphy, 
Lodge  was  not  slow  to  apply  his  knowl- 
edge to  this  subject. 

On  May  10,  1897,  Lodge  applied  for  a 
provision  patent  protection  in  Great  Britain 
for  improvements  in  Syntonizing  Teleg- 
raphy Without  Line  Wires,  and  in  this 
document  he  states  that  the  subject  of  his 
invention  was  to  enable  an  operator  to 
transmit  messages  across  space  to  any  one 
or  more  of  a  number  of  different  individ- 
uals in  various  localities,  each  of  whom  is 
provided  with  a  suitably  arranged  and 
"tuned"   receiver.     The   subject-matter  of 


service,  in  recognition  of  his  invention  of 
the  telephone  in  1876. 

The  medal  was  established  in  1914  to  ex- 


press the  sentiment  of  the  American  people 
toward  their  great  living  men  and  women. 
Its  purpose  is  to  promote  more  general  ap- 
preciation of  distinguished  public  service 
and  inspire  ambition  to  emulate  such  ser- 
vice. 

The  medal  this  year  was  awarded  to  Dr. 
Bell  by  vote  of  the  members  of  the  National 
Council  of  Seventy,  representing  the  whole 
country,  geographically  and  so  far  as  pos- 
sible in  all  other  respects. 

The  medal  was  first  presented  to  Maj. 
Gen.  George  Washington  Goethals,  U.  S. 
A.,  in  1914  for  his  work  in  building  the 
Pan  ama  Canal.  In  1915  it  was  presented  to 
Thomas  A.  Edison  in  recognition  of  his 
contributions  to  electrical  inventions. 


the  specification  deals  exclusively  with  the 
utilization  of  electromagnetic  waves.  This 
is  the  noted  Lodge  tuning  patent  which 
is  universally  employed  in  all  forms  of 
radio  transmitting  apparatus  today.  The 
patent  recently  expired  and  became  public 
property. 

Sir  Oliver  Lodge  is  a  noted  author,  and 
some  of  his  most  important  works  are 
"Elementary  Mechanics,"  "Modern  Views 
of  Electricity,"  "Pioneers  of  Science,"  "Sig- 
nalling Thru  Space  Without  Wires,"  "Life 
and  Matter,"  "Lightning  Conductors  and 
Lightning  Guards,"  "Modern  Views  of  Mat- 
ter," "Man  and  the  Universe,"  and  his  latest 
book,  "Raymond — A  Treatise  of  Life  and 
Death,"  which  purports  to  prove  that  the 
author  actually  received  communications 
from  his  dead  son,  who  was  killed  while 
serving  with  the  English  army  in  France. 
His  theory  however  was  received  coldly 
by  the  scientific  world. 


HOW  ELECTRIC  VEHICLES 
BOOST  EFFICIENCY. 

A  New  York  department  store  speeds 
up  the  loading  of  its  delivery  wagons  by 
running  its  "electrics"  inside  of  the  build- 
ing and  transporting  them  to  various  floors 
on  large  elevators. 


Copyright  by  Internationa!  Film  Service. 


The   Inspiring   Moment  When   Professor   Bell,   Inventor  of  the  Telephone,   Was  Presented 
With  the  "Civic  Forum   Medal"  at  New  York,  on   March  21st.     Reading   Left  to   Right — 
John  J.  Carty,  Union  N.  Bethell,  Dr.  John  H.  Finley,  Prof.  Bell  and  Thomas  A.  Watson, 
Who    Made   the    First   Telephone   for    Prof.  Bell. 


100 


THE   ELECTRICAL  EXPERIMENTER 


June,  1917 


Joe's  Experiment 


t<     A^'D  another  thing,"  Mr.  Robertson 
/\      checked  Pete ;  "don't  bring  that 
/  \    blind  kid  around  here  any  more. 
He's  just  in  the  way,  and  if  he 
gets  hurt  the  company'll  have  the 
damages   to  pay.     What   business   has  a 
blind   kid   got   around    an    electric  plant, 
anyhow?     You   keep   him   out    of  here, 
understand  ?" 

Pete  Foley  whirled  and  surveyed  the 
nervous,  drawn  face  of  his  chief  for  a 
moment,  and  then  flung  back  hotly : 

"Look  here,  that  boy's  a  friend  of  mine 
and  a  mighty  good  friend.  He's  not  in 
your  way  when  he  comes  around  here,  and 
I'm    responsible   for  his   safety.     As  for 


By  C.  M.  Adams 

the  mountain-side,  Joe  Benson  paused  and 
listened  to  the  faint  purr  of  unit  No.  1, 
far  away  down  the  slope.  Ever  since  the 
Snake  River  Power  Company  had  started 
the  first  day's  work  on  this  water  power 
project,  Joe  had  been  an  interested  listener 
of  everything  that  went  on.  Listening  had 
been  his  chief  avenue  of  impression,  for 
his  eyes  were  useless,  and  had  been 
so  for  several  years.  He  had  heard  the 
rumble  of  the  blasts,  and  the  grit  and 
grind  of  drills  and  steam  shovels  as  they 
prepared  for  the  big  concrete  dam  which 
held  back  the  water.  He  had  listened  and 
been  interested,  but  mystified,  until  Pete 
Foley,  a  member  of  the  electrical  construe- 


as  much  about  the  plant  as  I  do,"  one  of 
them  ejaculated  admiringly,  after  Joe  had 
come  off  victorious  in  a  technical  argument. 

"Sure  he  does,"  Pete  retorted.  "Don't 
think  he  don't  know  anything  because  he 
can't  see.  He'll  make  his  mark — you 
watch."  « 

At  first  the  size  of  the  Snake  River- 
project  had  dazzled  Joe.  Then  with  a 
realization  of  the  extent  of  the  undertak- 
ing had  come,  at  first  as  a  dream,  and 
then  a  resolve,  the  idea  that  he,  too,  would 
become  an  electrical  man,  an  electrical  en- 
gineer. True,  he  was  blind.  But  he  was 
attending  the  high  school  up  the  valley 
and  in  two  years  would  be  ready  to  enter 


"No,  you  don't.     Not  me,"  Pete  interrupted,  as  Mr.  Robertson  turned  to  him.    "Here's  the  boy  you  want  to  thank.     He  saved  your  plant 

and  not  me." 


what  business  he's  got  around  an  electric 
plant,  let  me  tell  you  that  he  knows  more 
about  electricity  right  now  than  some  men 
who  are  paid  big  money  for  what  they 
are  supposed  to  know.  He'll  make  his 
mark  some  of  these  days  when  he  gets 
into  the  electrical  world,  you'll  see.  And 
furthermore,  he's  going  to  come  here  when- 
ever he  wants  to,  as  long  as  I'm  around." 

Mr.  Robertson's  white,  haggard  face 
flushed  angrily  and  his  lips  parted  as  if  to 
speak.  But  he  was  silent  as  Pete  swung 
out  of  the  power  house  and  up  the  trail  to 
the  company's  tool  shack.  Pete  Foley  was 
a  good  electrician,  a  very  good  electrician, 
and  men  with  this  particular  kind  of  good- 
ness were  so  scarce  in  these  mountains 
that  it  behooved  Mr.  Robertson  to  stand 
for  much  from  this  member  of  his  con- 
struction crew. 

Half  way  up  the  road  to  his  home  on 


tion  crew,  had  come  to  board  at  his  home. 

It  was  Pete  who  had  answered  his  hows 
and  whys  about  the  plant  and  its  opera- 
tion, and  during  the  year  which  had 
elapsed  Joe  absorbed  electrical  information 
like  a  dry  sponge  taking  in  water. 

At  first  he  had  listened  to  the  conversa- 
tion of  the  men,  but  had  been  loath  to 
take  part  in  it  because  he  felt  his  own 
ignorance  of  their  work.  However,  as 
time  past,  and  Pete's  daily  instructions  bore 
fruit,  he  began  to  take  a  more  active  part 
in  the  talk  of  the  men  during  the  evening. 

At  first  they  had  regarded  him  as  an 
outsider,  whose  ignorance  of  their  work 
was  to  be  tolerated  for  politeness  sake  only. 
But  gradually,  as  Joe's  comments  and  ques- 
tions became  more  intelligent,  they  began 
to  look  to  him  as  an  equal — as  one  of  their 
own  number  professionally. 

"I'll  be  hanged  if  that  kid  don't  know 


the  university.  Other  blind  men  had  done 
things  equally  as  wonderful.  Why  could 
he  not  enter  this  field? 

And  what  a  day  this  had  been,  what  a 
wealth  of  impression  and  sensation.  He 
had  stood  beside  the  great  towering  masses 
of  iron  and  copper, and  had  felt  with  his 
own  sensitive  hands  the  giant  castings  and 
coils  of  the  great  generators,  while  Pete 
explained  how  they  were  built  and  worked. 
So  this  April  afternoon  he  went  home 
warmly  glowing  with  new  impressions  and 
desires. 

Pete  did  not  have  time  to  talk  after 
supper.  He  went  upstairs  for  his  clothes 
and  then  disappeared  down  the  slope  in 
the  company  car,  on  his  way  to  Merwin 
to  complete  preparations  for  the  trans- 
formers in  the  sub-station  there.  And  so 
Joe  sat  on  the  porch  and  listened  to  the 
faint  hum  of  the  generators  below  him, 


June,  1917 


THE   ELECTRICAL  EXPERIMENTER 


101 


L 


while     lie     dreamed     of     his  future. 

Two  days  later  when  Pete  returned  from 
Merwin,  Joe  was  waiting  for  him  after 
supper  as  the  group  of  boarders  gathered 
on  the  porch. 

"Pete,"  Joe  began,  "I've  been  wanting  to 
ask  you  something  since  day  before  yester- 
day, but  you  weren't  here  to  answer  it." 

"Go  ahead,  but  don't  go  too  deep.  Re- 
member I'm  only  an  ordinary  electrician," 
Pete  warned. 

"Well,"  Joe  went  on, 
"on  one  of  those  switch-  ^^^^^^^ 
board  panels  you  showed 
me  the  other  day  there 
was  a  rheostat,  but  you 
didn't  say  what  it  was 
for.  What  does  it  do, 
anyhow?" 

"Oh,  that's  the  rheostat 
for  the  exciter's  field," 
Pete  responded.  "It's 
connected  in  the  shunt 
winding  of  the  exciter 
field  coils.  It  controls 
the  voltage." 

"What  does  it  do  that 
for?"  Joe  insisted,  going 
to  the  bottom  of  the  mat- 
ter. 

"Well,  here's  the  idea,"  Pete  explained. 
"You  see  the  exciter  supplies  current  to  the 
field  of  the  big  alternator.  Well,  the  volt- 
age of  the  alternator  will  depend  on  the 
voltage  of  the  exciter,  because  if  the  volt- 
age of  the  exciter  changes  the  strength  of 
the  field  will  change  and  affect  the  alter- 
nator's voltage.  So  if  they  want  to  raise 
or  lower  the  voltage  of  the  big  alternator, 
they  just  raise  or  lower  the  exciter  volt- 
age by  putting  in  more  or  less  resistance 
with  this  rheostat.    Do  you  understand?" 

"Oh,  yes."  Joe  replied.  "Then  by  ad- 
justing this  field  rheostat  on  the  exciter 
you  can  change  the  voltage  of  the  big 
alternator." 

"Exactly."  Pete  assented. 

Joe  sat  for  some  moments,  thinking  of 
this  new  addition  to  his  store  of  electrical 
information,  while  the  men  about  him 
talked  lazily. 

"Robertson's  getting  grouchy  about  those 
transformers.  I  tell  you,"  one  of  the  men 
said  a  moment  later. 

"If  they  don't  come,  the  company  won't 
be  able  to  get  its  franchise,  and  he  seems 
to  think  it's  up  to  him  to  get  them  here." 

"I  know  that  all  right,  but  he  oughtn't 
to  treat  the  rest  of  us  like  we  were  to 
blame,"  Pete  retorted.  "He's  been  a  fright 
for  the  last  two  weeks." 

"What  transformers  are  those?"  Joe 
asked. 

"The  transformers  for  the  Merwin  sub- 
station, the  step-down  set,"  Pete  informed 
him. 

"Haven't  they  come  yet?"  Joe  asked  in 
surprise. 

"No,  they've  been  shipt  a  week  but  can't 
be  located  on  the  road  or  anywhere  else." 

"What  will  he  do  if  they  don't  come?" 
Joe  asked  in  concern. 

"I  don't  know.  That's  what's  bothering 
him,  I  guess,"  Pete  replied. 

The  generators  at  Portage  Falls  devel- 
oped current  at  low  voltage  which  was 
then  past  thru  a  set  of  transformers  which 
stept  it  up  to  sixteen  thousand,  five  hun- 
dred volts,  at  which  tension  it  was  trans- 
mitted to  Merwin,  fifteen  miles  away  over 
the  mountains.  There  it  was  stept  down  to 
two  thousand,  three  hundred  volts  for  dis- 
tribution thru  the  service  lines  of  the  city. 
Joe  knew  this  as  well  as  the  rest  of  the 
men.  He  also  knew  now  that  if  the  step- 
down  transformers  did  not  arrive,  the 
Snake  River  Power  Company  would  be  in 
a  very  awkward  position. 

Its  franchise  required  it  to  supply  cur- 
rent to  Merwin  on  May  first.  Today  was 
April  twenty-seventh. 


Joe  knew  that  the  sixteen  thousand  volt 
current  could  not  be  turned  directly  into 
the  city  lines.  He  knew  that  burned  out 
equipment  and  electrocuted  people  would 
be  the  result.  The  voltage  had  to  be  low- 
ered, but  how?  He  wondered  about  it  and 
tried  to  think  what  Mr.  Robertson  would 
do,  as  he  sat  on  the  porch  and  listened 
to  the  men  talking,  and  far  away  the  faint 
hum  of  the  generators  in  the  power  house, 
limbering  up  their  bearings.- 


AST  month  we  publisht  a  rattling  good  story — "Eddy  Currents" — 
by  Mr.  Adams.  We  confidently  believe  that  the  present  tale  will 
appeal  to  all  dyed-in-the-wool  electrical  readers.  You  don't  require  an 
electrical  education  to  become  "en  rapport"  with  the  author,  as  he  pos- 
sesses that  happy  faculty  of  weaving  the  technical  and  personal  aspects 
in  such  a  way  that  the  moral  cannot  be  mist.  The  facts  related  in  this 
story  are  human,  pertinent  every-day  affairs.  Similar  obstacles  to  those 
facing  invincible  Joe  Benson,  the  hero  of  this  narrative,  have  confronted 
all  of  us  at  one  time  or  another.  But  true  "Philosophy"  will  unlock  all 
doors  and  surmount  the  greatest  of  barriers. 


Of  what  use  would  this  power  be  if 
there  were  no  transformers  at  Merwin? 
Without  the  intervening  coils  the  big  ma- 
chines would  be  as  useless  as  if  their  wind- 
ings were  stript  from  them.  He  thought 
of  this  and  tried  to  answer  for  himself  the 
question  that  was  puzzling  the  chief  of 
construction. 

"What  do  you  suppose  Mr.  Robertson 
will  do?"  he  asked  Pete  as  the  latter  started 
upstairs  for  bed. 


IN  THAT  "JULY"  E.  E. 

Arc  There  Currents  About  a  Mag- 
net?— with  a -number  of  original  pho- 
tos and  charts  never  publisht  before. 
— by  F.  F.  Mace. 

"Cold  Light"  or  La  Lumiere  Froide, 
as  the  French  call  it.  The  work  of 
Prof.  Dussaud. 

Back  to  the  Days  of  "V  olta"—n.vith 
some  extremely  interesting  photos  of 
Volta's  original  apparatus — by  Jacques 
Boyer,  our  Paris  Correspondent. 

"Ham  Jones — Scientist" — a  rollick- 
ing good  electrical  story  with  a  live- 
wire  wallop  in  every  line  by  H.  IV. 
Eveleth. 

The  Marvels  of  Radioactivity  by 
Jerome  S.  Marcus. 

Lightning — How  to  Protect  Your- 
self from  It — An  article  everyone 
should  read  by  W.  G.  Whitman. 
With  illustrations. 

Where  the  Radio  Amateur  Fits  in 
the  U.  S.  Naval  Reserve  Force  by 
M.  B.  West. 

A  Page  of  Marvelous  X-Ray  Skia- 
graphs, including  one  of  a  four- 
legged  chicken. 

The  Calculation  and  Measurement 
of  Inductance — Conclusion  by  H. 
Winficld  Secor  and  Samuel  Cohen. 

Besides  these  and  a  large  num- 
ber of  other  valuable  and  interesting 
articles,  there  ivill  appear  a  liberal 
sprinkling  of  timely  summer-time 
topics  of  interest  to  all  readers.  Don't 
miss  the  "July  Issue!"  It'll  be  right 
there  waiting  for  you  with  a  zvallop 
on  every  page. 


"Go  crazy,  if  those  transformers  don't 
come,"  Pete  replied  unconcernedly. 

The  next  day  Joe  found  himself  think- 
ing of  the  problem  again  as  he  heard  the 
machines  purring  away  on  his  way  home 


from  school.  That  night  as  he  sat  on  the 
porch  he  was  still  thinking  of  it,  and  yet 
had  found  no  ready  solution  for  the  dif- 
ficulty. 

"I  don't  see  how  they're  going  to  fix 
that  up  if  those  transformers  don't  come," 
he  complained  to  Pete. 

"Great  guns,  you  aren't  trying  to  figure 
out  a  way,  are  you?"  Pete  exclaimed. 

"Why  yes,  I  ought  to  be  -  able  to,  or  try 
anyhow,"  Joe  protested. 

"Let  Robertson  do  that. 
^^^^^^^        He's  paid  for  worrying," 
Pete  returned  easily. 

But  that  did  not  satisfy 
Joe.  The  plant  below 
him  had  grown  under  his 
very  doorstep.  He  had 
heard  every  bit  of  metal 
and  concrete  put  into 
place,  and  he  felt  as  if 
the  thing  were  his  own. 
Then,  too,  was  he  not  go- 
ing to  be  a  consulting  en- 
gineer some  day ;  would 
not  a  problem  similar  to 
this  be  put  to  him  for 
solution  ?  He  ought  at 
least  to  attempt  to  solve 
it  now.  So  he  puzzled 
his  brain  over  the  thing  that  night  and 
all  the  next  day,  suggesting,  rejecting, 
scheming  and  pondering.  But  by  the  eve- 
ning  of  the  twenty-ninth  he  had  not 
reached  any  solution. 

He  was  not  the  only  one  who  was  think- 
ing of  this  problem.  The  worried,  anxious 
face  of  Mr.  Robertson,  with  its  black- 
ringed  eyes,  glittering  with  sleeplessness, 
testified  too  plainly  of  his  own  struggle 
over  the  proposition. 

He  remained  at  Portage  Falls  directing 
bits  of  finishing  work,  while  he  hoped  and 
almost  prayed  for  the  momentary  arrival 
of  the  coils  so  much  needed.  Hourly  he 
telephoned  to  Merwin  to  see  if  they  had 
arrived.  Hourly  he  hoped  that  they  might 
have  come,  and  then  grew  despairing  as  he 
was  told  they  had  not. 

On  the  morning  of  the  thirtieth  he  went 
to  Merwin  with  the  determination  of  stay- 
ing there  until  they  came,  and  hoping 
against  hope  that  service  could  be  started 
on  time. 

Pete  and  the  others  stayed  behind  at 
Portage  Falls,  finishing  up  fine  points  of 
the  work  there.  The  plant  was  in  order, 
each  great  machine  ready  to  send  its  thou- 
sands of  kilowatts  over  the  line  to  Merwin 
to  be  used  for  every  sort  of  work,  pro- 
vided the  intervening  transformers  were 
there  to  step  down  the  deadly  high  tension 
to  a  safe  voltage.  But  at  noon  a  message 
to  the  Falls  reported  that  no  transformers 
bad  arrived. 

Pete  loafed  up  the  steps  of  the  Benson 
home  at  dinner  time.  Worry  over  what 
would  happen  to  the  company  did  not  in- 
terfere with  his  appetite,  and  he  was  ready 
for  the  food  awaiting  him. 

But  five  minutes  after  he  had  sauntered 
leisurely  inside,  he  dashed  out,  leaped  off 
the  porch,  and  raced  down  the  steep  hill- 
side, recklessly  speeding  toward  the  com- 
pany's tool  shack  at  the  bottom.  A  minute 
later  he  flung  open  the  doors  of  the  build- 
ing and  was  cranking  the  little  service 
automobile.  Two  minutes  later  and  the 
pebbles  were  flying  in  a  stream  from  his 
tires  as  he  bumped  away  over  the  rough 
roads  toward  Merwin 

An  hour  and  a  half  later  he  stopt  Mr. 
Robertson's  big  high-power  roadster  before 
the  building,  while  the  chief  himself  sprang 
out  and  dashed  down  to  the  power  house, 
with  Pete  closely  pursuing  him. 

*         *         *  *         *  * 

It  was  a  varied  group  which  clustered 
about  the  switchboard,  handsomely  drest 
directors,  oilers  and  workmen  in  overalls, 
(Continued  on  page  150) 


102 


THE  ELECTRICAL  EXPERIMENTER 


June,  1917 


AN  ELECTRIC  SEMAPHORE  FOR 
AUTOISTS. 

The  accompanying  photograph  shows  a 
cleverly  designed  automobile  electric  sig- 
nal device  which  has  recently  been  devel- 
oped by  the  well-known  civil  engineer,  Mr. 
H.  Hartman,  of  New  York  City. 


Ll 


hands  or  not,  as  becomes  readily  apparent. 

The  Instructograph  consists  of  three 
units :  the  transmitting  unit,  the  receiving 
unit  and  a  battery  case,  and  while  the  pieces 
are  of  light  and  compact  construction,  the 
complete  installation  weighing  but  six 
pounds,  without  batteries,  they  have  been 
designed  for  the  strength  and  durability 
necessary  for  the  hard  usage  they  will  be 
subjected  to  in  service. 

The  Transmitter  consists  of  a 
case,  of  light  metal  construc- 
tion, about  six  inches  long,  three 
inches  thick,  and  an  inch  wide. 
A  series  of  six  double  throw 
keys  project  from  one  edge,  to 
the  right  and  left  of  which  ex- 
Motorists  Will  Be  Interested  In  the  ternd  engraved  plates,  bearing  all 
Electric  Semaphore  Signal  Here  lllus-  ot  the  instructions  commonly 
trated.  It  Is  Operated  By  Electro-  usecl  ;n  teaching  the  art  of  flying. 
Magnets,  Controlled  By  a  Push  Button  T,       ,  ^uS-h    or*    nf  e,,r-1n 

On  the  Steering  Wheel.  The  Arm  llle  keys.  Which  are  Ot  such 
Hangs  Downward  Normally,  and  Car-  size  that  they  can  be  easily 
ries  a  Red  Signal  Lamp  At  Its  Ex.-  bundled  with  gloved  hands,  can 

be  thrown  to  either  the  right  or 
left,  remaining  in  the  position 
placed  until  released  by  a  touch,  when  they 
fly  up  to  their  normal  vertical  position.  The 
twelve  instructions  themselves,  neatly  let- 
tered, have  been  chosen  with  great  ingenu- 
ity and  are  so  placed  that  actual  air  work 
cannot  necessitate  the  use  of  both  of  the 
two  directions,  placed  by  each  of  the  keys, 
at  the  same  time.  The  case  itself  can  either 
be  fastened  bv  the  side  of  the  instructor,  or 


tremity. 


The  Bull's-eye  At  the 
Is  Also  Illuminated. 


This,  like  other  inventions  of  Mr.  Hart- 
man,  is  really  quite  simple  in  construction 
and  performs  its  functional  duty  just  as 
well,  or  perhaps  better,  than  many  existing 
and  more  complicated  similar  devices.  The 
sole  purpose  of  this  instrument  is  to  warn 
an  automobilist  in  which  direction  the  ma- 
chine ahead  of  him  is  going  to  turn,  either 
to  right  or  left. 

It   consists   of   a  mag-   

netic  field  having  two 
magnetizing  coils  similar 
in  design  to  the  field  of  a 
motor.  An  armature  coil 
is  placed  in  this  field,  and 
its  shaft  is  attached  to  the 
signal  or  semaphore  arm. 
The  field  and  armature 
are  enclosed  in  a  water- 
proof metal  case  which  is 
seen  on  the  left.  One  end 
of  the  pointer  is  fitted 
with  a  red  lamp  so  as  to 
serve  as  a  danger  signal. 

The  armature  and  field 
coils  are  connected  to  a 
storage  battery  and  a  sim- 
ple switch,  so  that  the  au- 
toist  can  throw  the  arm 
either  towards  the  left  or 
right,  whichever  the  .case 
might  be.  The  principle 
upon  which  this  instrument  is  based  is  that 
of  the  repulsion  and  attraction  of  two  dif- 
ferent magnets,  one  stationary  (the  field), 
while  the  movable  magnet  is  the  armature. 
The  arm  at  its  normal  position  points 
downward,  and  as  soon  as  the  proper  cur- 
rent is  past  thru  the  field  and  armature, 
the  pivoted  arm  turns  instantaneously  to 
that  direction,  by  virtue  of  the  attraction 
between  a  field  coil  and  the  armature  coil. 
Automobilists  of  to-day  whose  slogan  is 
Safety  First  will  appreciate  this  very  valu- 
able device,  as  it  cannot  be  mistaken  owing 
to  the  relatively  large  moving  surface  called 
into  play. 

AN  ELECTRIC  INSTRUCTOGRAPH 
FOR  TEACHING  AVIATORS. 

One  of  the  latest  Sperry  devices  for  avi- 
ators, or  rather  for  would-be  aviators,  -is 
known  as  the  Instructograph  and  is  illus- 
trated herewith.  It  is  intended  to  facili- 
tate the  instruction  of  pupils  in  the  modern 
two-passenger  tractor  aeroplane.  Prior  to 
the  advent  of  this  clever  device  the  Pilot- 
Instructor,  occupying  the  rear  seat  of  the 
machine,  depended  on  twitching  the  various 
controls,  after  attracting  the  attention  of  his 
pupil-passenger  by  kicking  the  back  of  the 
forward  seat,  for  imparting  such  instruc- 
tion as  was  necessary.  This  crude  method 
of  communication  is  very  dangerous,  as  at 
times  neither  pupil  nor  instructor  know 
whether  the  control  of  the  plane  is  in  their 


The  Electrically  Operated  "Instructograph"  Enables  the  Tea 
Up  the  Proper  Signals  Instantly  Before  the  Pupil- Passenger; 

Superior  to  Twitching  the  Various  Controls. 


set  into  the  instrument  board  before  him, 
as  found  convenient. 

The  Receiver  is  a  box  approximately  sev- 
en inches  long,  five  inches  wide  and  slightly 
over  one  inch  thick,  adapted  to  fasten  on 
the  wheel  of  the  front  control  itself  in  the 
front  cockpit  of  a  tractor,  under  the  cowl, 
or  in  the  instrument  board.  Its  cover  is 
perforated  by  twelve  oblong  windows, 
closed  by  translucent  white  celluloid,  with 
no  lettering  of  any  kind  visible  to  confuse 
the  pupil.  When  one  of  the  keys  of  the 
Transmitter  is  thrown,  the  corresponding 
direction  appears  on  a  window  in  dense 
black  against  an  illuminated  white  back- 
ground. Three  of  the  directions :  "Nose 
Down,"  "Over  Banking"  and  "Over  Con- 
trolling" flash  out  in  black  against  a  red 
background,  clearly  indicating  the  urgency 
of  the  command.  An  ingenious  arrange- 
ment of  small  electric  light  bulbs  enables 
this  method  of  communication  to  possess 
the  advantage  of  positively  attracting  the 
pupil's  attention  whenever  a  word  of  in- 
struction is  given,  it  having  been  found  ex- 
perimentally that  the  flash  of  light  accom- 
panying the  change  of  direction  catches  his 
subconscious  attention.  To  safeguard 
against  the  possibility  of  a  burned  out  bulb 
preventing  the  direction  from  being  re- 
ceived, the  circuits  are  so  arranged  that  a 
second  lamp  remains  lighted. 


NEW    METHOD    OF  MEASURING 
FRESSURE  OF  LIGHT. 

In  a  paper  to  the  Physical  Society,  Mr. 
Gilbert  D.  West  describes  the  measurement 
of  the  pressure  of  light  by  a  method  re- 
quiring few  of  the  elaborate  precautions 
generally  necessary  in  such  experiments. 
The  essential  feature  of  the  apparatus  was 
a  strip  of  gold  leaf  suspended  in  the  mid- 
dle of  a  test  tube  containing  air  or  hydro- 
gen at  reduced  pressure.  Radiation  from 
a  32  c.p.  carbon  filament  lamp,  impinging 
directly  on  one  side  of  the  strip,  was  suf- 
ficient to  cause  a  microscopically  measure- 
able  deflection  of  the  end. 

The  pressure  of  normally  incident  radi- 
ation on  a  perfectly  reflecting  surface  has 
been  shown  by  Maxwell  and  others  to  be 
numerically  equal  to  twice  the  energy  con- 
tent of  the  radiation  per  unit  volume,  and 
hence,  if  this  quantity  be  measured  in  the 
way  described  below,  a  check  on  the  orig- 
inal observations  can  be  made.  A  mean 
of  the  results  of  several  successive  experi- 
ments with  the  deflected  strips  gave  a  value 
for  the  pressure  of  radiation  which  only 
differed  from  that  calculated  from  the  en- 
ergy density  by  a  small  percentage.  The 
accuracy  and  constancy  of  the  final  results 
seemed  to  preclude  their  being  seriously 
affected  by  gas  action;  but,  as  gas  action 
had  to  be  taken  into  consideration,  the  pres- 
ent research  was  undertaken  with  a  view  to 
its  fuller  investigation,  and  if  possible  to 
complete  elimination. 

In  measuring  the  energy 
density,  the  initial  rate  of 
rise  of  temperature  of  a 
blackened  copper  plate, 
enclosed  in  the  tube,  was 
measured  by  means  of  an 
attached  copper  eureka 
thermo-junction.  Due  al- 
lowance was  made  for 
cooling  corrections,  and 
the  lamp  black  was  as- 
sumed to  absorb  95  per 
cent  of  the  incident  radi- 
ation. The  cold  junction 
was  immersed  in  oil  con- 
tained in  a  vacuum  flask, 
and  during  an  experiment 
a  delicate  indicating  ther- 
mometer in  the  oil  only 
showed  negligible  varia- 
tions. The  calibration  of 
the  thermo-junction  was 
carried  out  in  the  usual  way,  and  a  num- 
ber of  minor  matters  received  full  con- 
sideration. 

When  from  the  measurements  thus  taken 
the  energy  reaching  1  sq.  cm.  in  one  second 


cher  to  Flash 
which  Is  Far 


Arrangement  of  Apparatus  for  Measuring 
Pressure  of  Light. — H  is  Hollow  Stopper,  E 
Is  Cover  Glass  Cemented  to  Tube.  F  Con- 
tains Pith  Charcoal,  G  Is  Tube  Which  May 
Be  Connected  to  Gaide  Pump. 

is  known,  the  energy  per  1  c.c.  can  be  cal- 
culated from  a  knowledge  of  the  velocity 
of  light. 

(Continued  on  page  142) 


June,  1917 


THE  ELECTRICAL  EXPERIMENTER 


103 


NEW  TELEPHONE  SIGNAL  A 
PATIENCE  SAVER. 

Patience  vanishes  rapidly  while  holding 
a  telephone  line.  Save  your  time  and  at- 
tend to  other  important  matters  while  wait- 
ing for  the  other  party  to  resume  conver- 
sation, say  the  sponsors  of  the  new  Hold- 
the-call-signal  here  illustrated.    This  clever 


tries  to  drum 


How  Often  Do  You  Feel  Like  Cussing  the 
Telephone  When  Party  No.  2  Says  "Hold  the 
Line"?  The  Answer  Is — Don't.  Place  the 
Receiver  On  the  Amplifier  Here  Shown  and 
You  Will  Hear  the  Party  Answer. 

device  will  let  you  know  when  the  speaker 
is  ready.  No  electrical  connection  is  needed. 
It  simply  rests  alongside  of  the  instrument 
and  the  receiver  is  placed  on  it  while  line 
is  held  open. 

HOW  STUDENTS  STUDY  WAVE 
MOTION. 

When  the  college  "Prof.' 
the  principles  of  wave  mo- 
tion into  his  pupils'  crani- 
ums,  he  has  available  to- 
day the  mechanical  wave 
reproduction  machine  here 
illustrated.  The  small  white 
discs  form  into  various 
lines  representing  curves  or 
waves  of  certain  kinds,  de- 
pending on  how  the  appa- 
ratus is  operated.  This  re- 
markable model  was  in- 
vented by  Dr.  Charles 
Forbes  of  Columbia  Uni- 
versity. With  this  appara- 
tus the  formation  and 
propagation  of  the  three 
general  classes  of  wave 
motions  may  be  demon- 
strated, namely : 

Water  or  Surface  Waves, 
in  which  the  elliptical  mo- 
tion of  the  particles  of 
water,  the  advancing  of 
the  crest  tending  to  form 
breakers,  the  recession  of 
the  trough  tending  to  form 
the  undertow  are  exhibited. 
Sound  Waves,  or  waves  of  condensation 
and  rarefaction,  in  which  the  amplitude 
of  vibration  may  be  changed  by  lowering 
the  disc  support.  The  lowering  of  the 
distant  end  of  the  support  will  also  repre- 
sent the  decrease  in  the  loudness  of  sound. 
Ether  Waves,  or  transverse  vibrations,  rep- 


UNIQUE    ELECTRIC  SOLDERING 
TOOL. 

A  Buffalo  concern  has  1  ^ntly  brought 
out  a  new  form  of  electric  soldering  tool. 
Among  these  tools  is  a  two-prong  iron  with 
prongs  of  solid  bar  brass  with  nickel- 
plated  finish.  This  type  of  iron  is  furnished 
in  capacities  of  150  watts,  250  watts  and 
500  watts.  All  are  designed  to  work  on 
low  pressure,  from  6  to  15  volts,  either  di- 
rect or  alternating.  This  pressure  can  be 
obtained  from  an  ordinary  lighting  or 
power  circuit,  either  25  or  60  cycles  by  in- 
terposing a  low-voltage  transformer,  or  a 
storage  battery  operating  at  a  pressure  of 
12  volts  can  be  used.  Under  no  circum- 
stances may  these  irons  be  used  on  any 
voltage  over  15. 

Another  type  is  the  two-handle  portable 
soldering  outfit.  This  is  composed  of  a 
single  prong  soldering  tool  attached  to  one 
wire  of  the  secondary  side  of  the  trans- 
former and  a  solder-feeding  tool  attached 
to  the  other  secondary  wire  of  the  trans- 
former. When  a  storage  battery  is  used 
the  single  prong  soldering  tool  is  attached 
to  the  negative  side,  and  the  solder-feeding 
tool  to  the  positive  side  of  the  latter. 

When  soldering  with  this  outfit  the  sin- 
gle prong  point  is  brought  to  bear  upon 
the  object  to  be  soldered,  and  the  solder- 
feeding  tool  is  brought  to  bear  upon  the 
spot  where  soldering  is  needed.  The  in- 
stant the  circuit  is  closed  the  heat  point 
glows  with  a  white  heat,  and  the  solder  is 
held  until  the  work  is  done.    The  current 


AN  AUTOMATIC  EXTENSION 
REEL  FOR  DROP  LIGHTS. 

The  automatic  extension  reel  here  illus- 
trated is  intended  for  drop  or  portable  elec- 
tric lamps.  It  is  simple  in  construction  and 
positive  in  operation. 


Several  Styles 
Voltage  A.C.  < 


By    Means    of    This    Oscillating  Pendulum 
Cabinet  It  Becomes  a  Sinecure  for  the  "Prof.'' 
to    Inculcate    His    Pupils   with    the  Funda- 
mentals of  Various  Wave  Motions. 


resenting  the  production  of  light,  heat  and 
electric  waves.  The  progressive  undula- 
tions of  a  vibrating  cord  are  also  repre- 


of  a  Unique  Electric  Soldering  Iron  That  Operates  On  Low 
r  D.C.     Closing  the  Circuit  Causes  the  Points  to  Heat  Up, 
When  the  Solder  Is  Applied. 

ceases  to  flow  as  soon  as  the  heating  point 
is  taken  from  the  work.  This  outfit  is 
made  in  150-  and  300-watt  capacities  and 
is  designed  for  use  on  direct  or  alternat- 
ing currents  up  to  12  volts  pressure. 


sented.  Comparison  of  Phases.  The  ap- 
paratus admits  of  a  ready  comparison  of 
similar  phases  in  the  three  systems  of  wave 
motions,  a  very  desirable  feature  not  pos- 
sest  by  any  other  form  of  wave  machine. 
By  means  of  the  covers  resting  upon  the 
framework  of  the  apparatus  any  one  or  two 
of  the  wave  systems  may  be  hidden  from 
view,  thus  leaving  the  remainder  for  spe- 
cial examination  when  desired.  The  front 
of  the  apparatus  exhibits  the  conversion  of 
rotary  into  direct  and  lateral  reciprocating 
rectilinear  motions.  On  the  back,  the  ac- 
tion of  the  crank  handle,  the  rod  connect- 
ing the  individual  cranks,  and  the  opera- 
tion of  the  double  parallel  rule  mechani- 
cal motion,  first  used  in  this  apparatus,  are 
clearly  exhibited.  Tts  large  size  is  espe- 
cially advantageous,  since  the  wave  forms 
can  be  clearly  seen  across  a  large  lecture 
room. 


A  Clever  Invention  in  the  Form  of  An  Auto- 
matic  Extension   Reel  for  Portable  Electric 
Lamps,   Which  Winds  the  30-foot  Cord  Up 
and  Swivels  in  Any  Direction. 

It  is  designed  especially  for  garages, 
blacksmiths,  factories,  stores,  or  any  busi- 
ness requiring  an  extension  light.  This 
reel  is  equipt  with  30  feet  of  lamp  cord, 
easily  secured  by  fastening  the  arms  of  the 
swivel  joint  to  ceiling  or  beam,  as  shown. 

This  swivel  joint  enables  one  to  walk  in 
any  direction  with  the  lamp.  It  has  an 
automatic  lock  ingeniously 
arranged  to  lock  and  hold 
the  lamp  any  distance  from 
the  reel.  A  slight  pull  for- 
ward unlocks  the  ratchet 
and  the  reel  revolves,  wind- 
ing the  cord  back  as  you 
advance  toward  the  reel 
with  lamp  in  hand. 

A   HANDY  ELECTRIC 
DRINK  MIXER. 

The  soda  clerk  used  to 
cuss  (inwardly)  merrily 
whenever  a  patron  called 
for  a  drink  that  required  a 
fancy  mixture — a  chocolate 
milk  shake  for  instance. 
Wherefore  and  hence  we 
have  in  our  midst  the  elec- 
tric drink  mixer  that  never 
tires — no  matter  if  you  had 
a  thirst  like  an  Arabian 
camel. 

The  electric  drink  mixer 
is  mounted  on  a  swinging 
bracket.  When  the  machine 
is  pushed  back  and  removed 
from  the  glass  it  takes  the  position  indi- 
cated by  the  dotted  lines.    Throwing  back 


When  You  Ask  for  a  Fancy  Drink  at  the 
Soda  Fountain  the  Dispenser  Now  Places  the 
Glass  Under  An  Electric  Drink  Mixer. 

the  bracket  operates  a  switch  which  breaks 
the  circuit.  The  swinging  down  of  the 
bracket    automatically    closes    the  circuit. 


104  THE  ELECTRICAL  EXPERIMENTER  June,  1917 


Electricity  and  Life 

The  Uses  of  High-Frequency  Currents  in  Medical  and  Lecture  Work 
By  FREDERICK  FINCH  STRONG,  M.  D. 
Lecturer  on  Electro-therapeutics,  Tufts  Medical  School,  Boston 


T 


Senses 


(Third  Article) 

HE  phenomena  of  high-frequency 
currents  offer  us  a  fascinating  held 
from  which  to  select  experiments  for 
public  lecture  demonstration.  In  his 
lectures  on  "The  Realms  Beyond  the 
the   author   has    used  high-fre- 


ductance  coil  being  adjusted  to  balance  the 
different  capacities  added  to  the  resonator 
terminal. 

This  little  resonator  is  made  by  winding 
600  turns  of  No.  30  triple  cotton  covered 
wire  upon  a  shellacked  paper  cone,  12 
inches  in  diameter  at  the  bottom,  5  inches 


Hardening  of  the  Arteries — Most  Dreaded  of  Ailments  in  Later  Life — Is  Successfully  Treated 
By  Placing  the  Patient  Within  a  Wire  Cage,  Thru  Which  High-frequency  Currents  Surge  at  a 
Frequency  of  600,000  Cycles  Per  Second:  D'Arsonval's  Method. 


at  the  top,  and  14  inches  high.  It  is  a 
difficult  matter  to  insulate  this  small  coil 
as  the  turns  of  the  winding  are  very  close 
together ;  it  can  be  done,  however,  by  the 
use  of  from  six  to  eight  coats  of  Armalac. 
The  primary  coil  is  a  ring,  18  inches  in 
diameter,  formed  of  five  concentric  turns 
of  thin  copper  ribbon  1  inch  wide.  The 
exciting  apparatus  is  the  same  as  that  de- 
scribed in  the  last  paper  in  connection  with 
the  large  resonator,  except  that  a  Yz  K.W. 
transformer  is  used  instead  of  the  heavy 
1  K.W.    (See  Fig.  2.) 

The  writer  also  employs  a  standard 
Clapp-Eastham  K.W.  Tesla  coil  excited 
by  the  same  apparatus  (see  Fig.  3).  Con- 
nected with  two  parallel  upright  wires  the 
spark  from  this  coil  will  run  up  and  re- 
peatedly reform  again  at  the  bottom, 
producing  a  very  spectacular  effect  (Fig. 
4). 

Another  brilliant  experiment  can  be  per- 
formed with  two  large  glass  flasks  (ordi- 
nary carafes  or  water-bottles  will  do). 
One  is  filled  with  water  containing  a  few 
drops  of  fluorescein  solution — (a  coal  tar 
dye) — the  other  with  water  to  which  a  small 
amount  of  bi-sulfate  of  quinine  has  been 
added ;  the  bottles  or  flasks  are  placed 
about  six  inches  apart  and  a  wire  from  the 
Tesla  coil  terminal  inserted  into  the  solu- 
tion in  each.  The  current  passes  down 
thru  the  water  and  the  arc  takes  place  be- 
tween the  glass  walls  of  the  two  flasks. 
The  ultra-violet  rays  from  the  discharge 
cause  the  water  in  the  flasks  to  become 
luminous — the  quinine  solution  with  a  pale 
blue  light,  the  fluorescein  with  a  beautiful 
apple-green.  The  discharge  apparently 
passes  directly  thru  the  glass  walls  of  the 
flask;  in  reality,  of  course,  the  current 
passes  by  induction  rather  than  conduction, 
the  flasks  acting  as  condensers  in  series. 
(See  Fig.  5.) 


quency  phenomena  to  demonstrate  the  ex- 
istence of  force  and  matter  beyond  the 
range  of  human  perception.  In  "The  Sci- 
ence of  the  New  Age"  he  has  employed 
similar  means  in  calling  attention  to  the 
fact  that  the  investigators  of  to-day  are 
leaving  the  crude  matter  of  earth  and  are 
dealing  more  and  more  with  Etheric  Force 
— and  with  matter  of  a  super-gaseous 
nature.  The  scientist  of  the  future  will 
have  to  provide  himself  with  instruments 
far  more  delicate  than  anything  hitherto 
dreamed  of  or  else  he  will  develop  super- 
normal powers  of  perception  by  the  mani- 
festation of  faculties  already  latent  in  the 
human  organism. 

For  the  traveling  lecturer  who  wishes  to 
employ  high-frequency  currents  in  his 
work,  the  large  resonator  described  in  the 
last  issue  of  The  Electrical  Experi- 
menter may  prove  somewhat  cumbrous  and 
difficult  of  transportation.  Those  who  wish 
a  lighter,  more  compact  apparatus  may  use 
the  small  resonator  shown  in  Fig.  1. 

It  is  quite  small,  yet  it  sends  out  stream- 
ers two  feet  in  length,  and  may  be  operated 
by  a  1 2  K.W.  "wireless"  (step-up)  trans- 
former. With  this  little  apparatus  beauti- 
ful luminous  effects  may  be  obtained — as, 
for  example,  by  connecting  the  terminals 
with  a  tin-foil  star  glued  to  a  sheet  of 
glass;  with  a  suspended  umbrella  (opened)  ; 
with  a  long  wire  running  out  over  the 
lecture  hall,  etc. 

For  each  of  these  experiments  different 
tuning   will  be  necessarv — the   series  in- 


The  "Effleuve"  or  High-frequency  Brush   (or  Spray)  Treatment  Has  Proven 
cacious  In  the  Treatment  of  Nervousness  (Nerve  and  Brain  Exhaustion) — "N 
American  Electro-therapeutists  Find  It  Very  Valuable. 


from  Jacques  Boyer 

Highly  Effi- 
eurasthenia." 


June,  1917 


THE   ELECTRICAL  EXPERIMENTER 


105 


The  Use  of  High-Frequency  Currents  in  the 
Treatment  of  Disease. 

High-frequency  currents  are  employed  by 
physicians  in  four  principal  ways,  each 
adapted  to  the  treatment  of 
certain  types  of  diseased  con- 
ditions.   These  are : 

1.  "Tesla"  treatment  with 
■vacuum  electrodes  ("Violet- 
ray  treatment"). 

2.  "EfHeuve"    or  high-fre- 
quency spray. 

3.  "D'Arsonval  auto- 
condensation." 

4.  "Diathermic" 

1.  The  method  most  fre- 
quently employed  applies  the 
Tesla  current  thru  glass 
(vacuum)  electrodes  for  the 
relief  of  local  pain  or  inflam- 
mation. The  little  muscular 
pumps  around  the  veins — the 
"vaso-motor  system,"  which 
keep  the  blood  circulating  by 
withdrawing  it  from  the  capil- 
laries and  sending  it  back  to 
the  heart — act  more  vigorously 
in  tissues  over  which  the 
vacuum  1  electrode  is  applied. 
In  this  manner  waste  products 
which  cause  rheumatism  and 
gout  are  dissolved  and  washed 
away  and  fresh  blood  and  white 
corpuscles  are  brought  to  in- 
fected parts,  thus  aiding  nature 
in  destroying  disease-producing 
germs  and  their  poisonous 
products. 

In  most  of  the  smaller  high- 
frequency  machines  for  phy- 
sicians' use,  but  one  Tesla 
terminal  is  provided ;  a  coil  of 
the  resonator  type  being  con- 
nected to  the  glass  electrode 
by  a  flexible  wire.  The  effects 
are  largely  local,  but  the  meth- 
od is  of  value  in  relieving  pain, 
swelling  and  congestion.  The 
writer  has  always  advocated 
the  bipolar  method,  even  for 
treating  purely  local  conditions. 
The  best  results  will  be  ob- 
tained from  the  use  of  a  Tesla 
outfit  of  the  type  described 
in  last  month's  Electrical 
Experimenter.  The  patient  is 
to  be  connected  to  one  terminal  of 
the  Tesla  coil  by  means  of  a  metal  electrode 
held  in  both  hands  ( a  piece  of  thin  nickeled 
pipe  will  answer,  1  foot  long  and  V/2  inches 
in  diam.).    In  this  way  the  current  is  dif- 


This  method— ■•employed  by  the  writer  for  By  careful  tuning  a  beautiful  effect  may 

years — enables  us  to  obtain  the  wonderful  be   obtained.     Close  examination   of  this 

vitalizing  effect  of  the  high-frequency  cur-  discharge  will  show  it  to  be  literally  an 

rents  on  the  whole  body  simultaneously,  electric  "brush",  formed  of  thousands  of 


Startling  Experiment  With  Two  Glass  Water 
Bottles  Connected  to  Tesla  Coil.    The  Spark 
Jumps    Between    the    Glass    Surfaces  and 
Illuminates  Solutions  Within  the  Bottles. 


fused  thru  the  entire  body.  The  vacuum 
electrode,  connected  with  the  opposite  Tesla 
terminal  is  applied  to  the  skin  over  the 
affected  part  for  from  five  to  twenty  min- 
utes, a  very  short  spark-gap  being  used. 


with  the  local  effects  from  the  vacuum 
electrode. 

For  the  past  few  years  the  writer  has 
been  in  the  habit  of  connecting  the  Tesla 
coil  with  an  Auto-condensation  pad  (as 
used  in  the  "D'Arsonval"  and  "Diathermic" 
methods).  This  is  formed  of  two  plates 
of  Bakelite,  Ms-inch  thick,  hinged  to  fit  the 
seat  and  back  of  an  ordinary  chair.  To 
the  back  of  each  plate  is  cemented  a  sheet 
of  tin  or  copper  foil,  covered  with  leather- 
ette. Suitable  flexible  conductors  connect 
these  metal  plates  with  each  other  and 
with  the  Tesla  terminal.  This  folding  pad 
may  be  used  in  both  "Tesla"  and  "D'Arson- 
val" treatment,  and  is  quite  as  efficient  for 
ordinary  use  as  the  cumbrous  and  expen- 
sive condenser  chair  or  couch. 

2.  For  the  "Tesla  Effleuve"  treatment  a 
brass  bell  electrode  is  used.  This  can  be 
made  from  a  common  brass  oil  can,  the 
flat  bottom  being  removed  and  the  result- 
ing hollow  hemisphere  being  mounted  on 
an  insulating  handle ;  the  discharge  occur- 
ring from  the  sharp  edge  of  the  brass.  The 
patient  is  seated  on  the  Bakelite  pad,  which 
is  connected  to  the  Tesla  coil.  The  oppo- 
site terminal  is  attached  to  the  brass  bell 
electrode  and  a  sufficient  number  of  turns 
of  the  inductance  coil  are  placed  in  series 
with  the  Tesla  primary  to  give  a  full, 
smooth  "effleuve"  or  purple  brush  dis- 
charge, when  the  .electrode  is  held  from 
four   to   eight   inches    from  the  patient. 


distinct,  delicate,  purple  threads.  Upon 
each  of  these  hair-like  paths  of  light  count- 
less millions  of  ions  (electrically-active 
atoms),  are  being  shot  from  the  electrode 
to  the  patient  at  a  speed  of  over  60,000 
miles  per  second ;  the  treated  surface  is 
therefore  being  submitted  to  a  literal  bom- 
bardment by  countless  microscopic  pro- 
jectiles which  are  thrown  out  in  periodic 
showers  from  the  electrode,  once  for  each 
cycle  of  the  oscillating  current.  Two  ef- 
fects are  produced — one  due  to  the  pene- 
tration of  the  tissues  by  ozone-forming 
ions:  the  second  to  the  rhythmic  or  periodic 
impact  of  the  discharge  upon  the  nerve 
endings  in  the  skin  and  superficial  tissues. 
The  writer  hopes  ultimately  to  produce  an 
apparatus  of  a  frequency  exactly  synchro- 
nous with  the  rate  of  vibration  of  the 
sensory  nerves;  an  "effleuve"  from .  such 
a  coil  would  produce  a  harmless  and  effi- 
cient local  anaesthesia  so  that  operations 
could  be  performed  without  the  use  of 
ether  or  cocain.  The  effects  obtained  from 
the  "effleuve"  as  now  used  are  stimulating 
and  vitalizing  to  a  marked  degree.  The 
nerve  endings  of  the  skin  may  be  regarded 
as  sensitive  antennae  of  a  complicated  ra- 
dio-system, and  any  intense  sustained  vibra- 
tion to  which  the  apparatus  is  attuned  will 
be  transmitted  by  them  to  the  receiving 
station.  The  effect  therefore,  is  not  merely 
superficial  but  systemic  as  well.  Tuber- 
(Continucd  on  page  152) 


106  THE  ELECTRICAL  EXPERIMENTER  June,  1917 

Experimental  Physics 

By  JOHN  J.  FURIA,  A.  B.,  M.  A. 

Instructor  in  Physics  and  Science  Master,  Riverdale  Country  School 


HYDROSTATICS. 
LESSON  FIVE. 

WATER  is  so  plentiful,  and  we  are 
accustomed  to  use  so  much  .of  it, 
that  very  few  of  us  ever  stop  to 
think  what  a  great  part  it  plays 
in  our  daily  lives.  It  is  without 
doubt    an    absolutely    indispensable  sub- 


A  Small  Battery  and  a  Couple  of  Test  Tubes 
or  Bottles,  Together  with  Connecting  Wires, 
Will  Serve  to  Clearly  Show  How  the  Electric 
Current  Decomposes  Water. 


stance.  We  drink  it — we  clean  ourselves 
and  our  belongings  in  it — our  crops  depend 
upon  it — ourselves  and  the  fruits  of  our 
toil  are  transported  from  one  continent  to 
another  by  means  of  it — practically  every 
manufacturing  industry  makes  use  of  it. 
Finally  and  most  important,  we  swim  in 
it.  What  would  be  the  use  of  living  if  we 
had  no  Palm  Beach  or  "the  old  swimming 
hole  in  the  creek"?  We  naturally  ask  what 
is  water  anyhow?  One  could  never  guess 
the  answer.  Water  is  nothing  more  than 
the  result  of  the  combining  of  two  gases — 
Oxygen  and  Hydrogen.  Oxygen,  we  re- 
member, is  the  constituent  of  the  atmo- 
sphere necessary  to  life.  Hydrogen  is  the 
gas  which  burned  with  a  pale  blue  flame 
in  the  lesson  on  "Gases."  (See  March  and 
April  issues  of  this  journal.)  The  follow- 
ing experiment  can  be  easily  performed 
successfully : 

EXPERIMENT  25— (See  Fig.  20)  — 
C  is  a  jar  nearly  full  of  water  to  which 
a  few  drops  of  sulfuric  acid  have  been 
added.  (The  sulfuric  acid  is  added  to 
make  the  water  a  better  conductor  of  elec- 
tricity. Water  alone  is  not  a  good  con- 
ductor of  electricity,  i.  c,  is  more  or  less 
of  an  insulator,  just  as  glass  is.)  D  rep- 
resents lead   wires   from  a  battery  of  at 


Demonstration   and    Controlling  Factors  of 

the    Hydrostatic    "Siphon".     A  Simple  and 

Effective    Method    of    Emptying  Tanks  and 

Even  Reservoirs  When  Occasion  Requires  It. 


least  six  dry  cells  in  series,  or  from  a 
storage  cell  or  from  the  house  current  if 


it  is  direct  current.  If  possible  the  elec- 
trodes should  be  of  platinum.  A  and  B 
are  test  tubes  held  in  the  hand  after  being 
inverted  full  of  water  and  are  placed  over 
the  electrodes.  Immediately,  and  with  a 
rapidity  dependent  upon  the  strength  of  the 
battery  used,  bubbles  will  form  at  the  elec- 
trodes and  rise  to  the  top  of  the  test  tubes. 
These  bubbles  are  the  result  of  the  decom- 
position of  the  water  into  its  constituents. 
We  notice  that  in  one  tube  the  bubbles 
form  more  rapidly  and  that  there  is  always 
about  twice  as  much  gas  in  that  test  tube 
as  in  the  other.  Call  that  test  tube  "B.'' 
After  the  test  tubes  have  been  filled  with 
the  gases,  raise  them  carefully  without  tip- 
ping. Insert  a  glowing  match-stick  in  "A." 
It  is  found  to  burn  brightly.  This  we  re- 
member was  the  test  for  Oxygen.  If  a 
flame  is  applied  to  "B"  a  slight  explosion 
results,  which  is  the  test  for  Hydrogen. 
Thus  we  see  that  water  is  composed  of 
two  parts  Hydrogen  to  one  part  Oxygen. 

EXPERIMENT  26— (Fig.  21)— Illus- 
trating the  principle  of  the  siphon.  A 
and  B  are  vessels  at  different  levels,  A 
being  higher  than  B.  The  vessels  are  con- 
nected by  a  piece  of  tubing ;  bb1  indicates 
the  level  of  the  top  of  the  tubing  and  aa1 
the  level  of  the  water  in  vessel  A.  d, 
indicates  the  level  of  the  end  of  the  tubing. 
If  the  tube  is  placed  in  position  as  indi- 


Two  Forms  of  Automatic  Siphon.  Details 
for  Constructing  the  One  on  the  Right  Are 
Given  Herein. 


cated  in  the  figure,  and  A  contains  water 
(or  any  liquid)  at  a  level  aa1,  nothing 
happens.  If,  however,  the  tube  is  filled 
with  water  before  it  is  placed  in  position, 
the  water  begins  to  flow  from  A  down 
to  B.  The  siphon  will  also  act  if  the  tube 
is  placed  in  position,  and  if  one  sucks 
at  the  lower  end ;  for  this  is  equivalent  to 
filling  the  tube  with  water.  The  explana- 
tion of  the  action  is  as  follows :  The  up- 
ward pressure  in  the  short  arm  of  the 
tube,  is  due  to  the  atmospheric  pressure 
(discust  in  the  last  two  lessons).  In  the 
tube  ab,  this  pressure  is  equal  to  the  atmo- 
spheric pressure  minus  the  downward  pres- 
sure due  to  the  weight  of  the  column  of 
water  ab.  The  upward  pressure  of  the 
tube  at  b1  is  the  atmospheric  pressure 
minus  the  downward  pressure  due  to  the 
weight  of  the  column  of  water  bM.  The 
force  tending  to  drive  the  liquid  from  A  to 
B  is  greater  than  that  tending  to  drive  it 
from  B  to  A.  It  is  greater  by  the  amount 
equal  to  the  difference  in  the  weight  of 
the  columns  ab  and  bM  and  hence  corre- 
sponds to  the  weight  of  the  column  aM. 
Evidently  if  d,  were  at  the  level  aa1,  the 
siphon  would  not  operate;  and  if  above 
aa1,  it  would  operate  in  the  other  direction. 
If  the  column  ab  (for  water)  were  greater 
than  32  feet  the  atmospheric  pressure  could 


not  raise  the  water  this  distance,  and  the 
siphon  would  not  operate. 

EXPERIMENT  27— Recently  an  auto- 
matic siphon  has  been  put  on  the  market, 
and  it  can  be  very  easily  constructed.  Fig. 
22  shows  the  automatic  siphon  in  the  act 
of  starting.  It  should  be  noticed  that  the 
tube  is  filled  alternately  with  bubbles  of  air 
and  water.    This  condition  prevails  only 


Apparatus  With  Which  the  Principle  of  the 
Submarine  Can  Be  Demonstrated.  The  Small 
Vial  2,  Can  Be  Made  to  Perform  Many  Won- 
derful Tricks  By  Pushing  Down  on  Diafram 
1,  or  Squeezing  Bottle  3  in  "B". 


upon  starting  and  shortly  after,  the  water 
comes  out  solidly.  Fig.  23,  shows  a  home 
made  automatic  siphon  and  all  those  inter- 
ested should  make  one.  6,  is  a  piece  of 
lamp  chimney  about  3  inches  long.  5,  is 
a  piece  of  glass  tubing  about  *4  inch  in 
diameter  stuck  thru  a  rubber  stopper  2. 
4,  is  some  more  of  the  same  kind  of  tubing 
past  thru  the  stopper  3.  The  height  h, 
should  be  about  a  foot  and  a  half.  1,  is 
a  small  hole  drilled  thru  the  lamp  chim- 
ney 6.  5  and  4,  should  be  about  ^4  of  an 
inch  apart.  As  soon  as  our  auto-siphon 
is  placed  in  a  liquid  it  begins  to  operate 
WITHOUT  OUR  FILLING  IT  FIRST. 
Thus  we  see  that  one  made  entirely  of 
glass,  as  are  the  commercial  ones,  is  very 
convenient  in  transferring  poisonous  liquids 
and  acids,  as  we  need  not  touch  the  liquid 
at  all.  There  is  nothing  mysterious  about 
this  siphon  and  it  is  easily  explained.  When 
the  bulb  is  immersed  in  the  liquid,  the 
liquid  rushes  in  at  1  and  at  the  lower  end 
of  tube  5.  The  liquid  rushing  in  at  1 
tends  to  compress  the  air  in  chamber  6. 
The  liquid  rushing  in  at  5  streams  up  past 
the  gap  and  thru  4.  Hence  the  outgoing 
air  takes  with  it  some  liquid,  and,  as  noted 
before,  we  see  alternately  passing  thru  the 


Proving  the  "Law  of  Buoyancy,"  i.  e.,  That 
Objects  Weigh  Less  In  Water  Than  In  Air. 


tube  bubbles  of  air  and  water.  As  there 
is  less  and  less  air  left  in  6,  larger  and 
larger  quantities  of  the  liquid  pass  with 
small  bubbles  of  air  intervening,  until 
finally  the  air  being  all  gone,  the  liquid 
(Continued  on  page  152) 


June,  1917 


THE  ELECTRICAL  EXPERIMENTER 


107 


»  RADIO  LEAGUE 


^AMERICA 


H.  Gcrnsback,  Manager 


HONORARY  MEMBERS 

CAPT.  WH.G  BULLARD.  U  S.N.  NIKOLA  TESL A , 
PROF  REGINALD  FESSENDEN.    DR. LEE  DE  FOREST. 

W.  H.  Kir  wan,  Master  of  Radio  Relays 


Denver  Wireless  Station  Wins  Prize  Loving  Cup 


TO  a  Denver  boy  goes  the  honor  of  win- 
ning the  trophy  cup  for  the  best  Ama- 
teur Wireless  Station  in  the  United 
States.    This  cup  was  donated  by  9XE  to 
the  most  efficient  and  best  equipt  amateur 
wireless  station  in  the  United  States. 

We  intended  to  call  in  a  committee  to 
decide  upon  the  merits  of  the  best  amateur 
stations  in  the  country,  but  station  9ZF  in 
Denver  was  so  far  ahead  of  all  other  ama- 
teurs in  sending,  receiving,  and  efficiency, 
that  it  would  have  been  a  waste  of  time 
and  energy  to  have  consulted  anyone  at  all. 

This  station,  9ZF,  is  known  to  every 
progressive  amateur  in  the  United  States, 
and  is  one  of  the  star  stations  of  the  Colo- 
rado Wireless  Association,  and  of  which 
you  have  all  read  in  a  previous  issue  of 


By  W.  H.  KIR  WAN  (9XE), 
Master  Radio  Relays,  Radio  League  of  America. 

issued  some  years  ago  to  Captain  Smith ; 
however,  the  station  really  belongs  to,  and 
was  made  by,  Mr.  Doig,  as  explained  above. 

A  record  of  messages  handled  at  9ZF 
from  January  13th  to  March  18th,  1917, 
shows  that  251  messages  were  received  and 
sent.  A  number  of  them  were  transcon- 
tinental messages  from  coast  to  coast. 
Station  9ZF  held  a  very  strategic  position 
in  the  Washington's  Birthday  Relay  of 
February  24th,  1917,  and  without  the  as- 
sistance of  this  station  it  would  not  have 
been  possible  to  have  sent  the  message 
thru  from  coast  to  coast,  nor  for  the  re- 
turn message  to  have  been  brought  back. 

We  believe  that  nearly  all  of  the  stations 
thruout  the  United  States  can  well  pattern 
their  installations,  as  far  as  general  ar- 


in    the    photograph    of    the  equipment. 

There  are  three  towers  to  Station  9ZF, 
one  of  them  being  90'  high  and  the  other 
two  75'  high.  One  aerial  has  six  No.  12 
aluminum  wires,  150'  long,  and  the  other 
aerial  has  four  stranded  aluminum  cables 
with  7  strands  of  No.  14  in  each  cable,  and 
is  200'  long.  Both  of  these  aerials  are 
connected  L  type. 

This  station  has  been  working  regularly 
with  amateur  stations  on  both  the  Atlantic 
and  Pacific  coasts.  Working  with  6EA  in 
Los  Angeles,  Cal.,  has  been  a  continuous 
past  performance,  and  recently  this  station 
has  worked  directly  with  2PM  in  New 
York  City.  We  claim  that  this  is  truly 
wonderful  work  for  an  amateur  station, 
and  we  do  not  think  that  there  will  be 


The  Trophy  Cup  for  the  Best  "Amateur  Wireless  Station"  in  the  United  States  Has  Been  Awarded  to  Station  9ZF,  operated  by  Messrs. 

E.  F.  Doig  (at  Right)  and  W.  H.  Smith  (Left),  of  Denver,  Colorado. 


this  magazine.  The  winner  is  Mr.  E.  F. 
Doig,  of  No.  848  South  Emerson  Street, 
Denver,  Colo.  Mr.  Doig  made  nearly  all 
his  apparatus  himself,  and  has  been  assist- 
ed by  Mr.  W.  H.  Smith  of  the  Y.  M.  C.  A. 
Radio  Club  and  the  Colorado  Wireless 
Association.  Mr.  Doig  was  for  four  years 
Master  Signal  Electrician  in  the  Signal 
Corps  of  the  Colorado  National  Guard.  He 
now  holds  a  special  receiving  and  sending 
license  from  the  United  States  Govern- 
ment. His  equipment,  altho  not  as  large 
as  the  Government  station,  is  very  com- 
plete, as  you  can  clearly  see  from  the 
photograph. 

Mr.  W.  H.  Smith,  also  well  known  for 
his  skill  as  an  operator,  is  associated  with 
Mr.  Doig  and  has  worked  on  his  night  shift 
at  this  station.  Mr.  Doig  is  also  secretary 
of  the  Colorado  Wireless  Association  and 
Mr.  Smith  is  the  chief  operator.  This 
station  will  hold  this  cup  for  one  year, 
and  if  they  win  it  again  in  1918  it  will 
belong  to  this  station  absolutely. 

The  cup  has  been  properly  engraved  and 
you  will  see  a  picture  in  this  magazine 
shortly  of  the  cup  holding  a  prominent 
place  in  the  Laboratory  of  Mr.  Doig.  The 
Government  Call  Book  gives  Station  9ZF 
as  belonging  to  Captain  Smith  of  the  Colo- 
rado National  Guard,  but  the  license  was 


rangement  and  efficiency  is  concerned,  after 
Station  9ZF.  Another  point  in  favor  of 
9ZF  was  the  fact  that,  while  this  station 
was  affiliated  with  nearly  every  Radio  Club 
and  organization  extant,  the  owners  never 
refused  a  message,  nor  did  they  feel  that 
Station  9ZF  was  too  proud  to  work  with 
anyone. 

In  the  receiving  cabinet  is  a  large  loose 
coupler  for  reception  of  long  wave  stations 
like  WG,  GW,  SL,  OUI  and  POZ,  as  well 
as  the  Government  arc  stations.  A  smaller 
receiving  cabinet  is  used  for  the  shorter 
wave  stations,  including  the  commercial 
coast  and  sub-stations  on  the  spark  sys- 
tem. There  is  also  a  short  wave  regenera- 
tive receiver,  which  is  used  in  working  with 
the  amateur  stations.  This  cabinet  also 
contains  an  amplifier  which  can  be  used 
in  connection  with  each  of  the  other  sets. 
There  is  not  much  to  tell  about  the  Rotary 
Quenched  Gap,  as  the  cut  shows  just  what 
it  is,  and  there  are  not  very  many  ama- 
teurs but  what  have  had  the  chance  to  read 
about  this  outfit. 

The  1  k.w.  outfit  which  is  used  mostly, 
radiates  from  12  to  14  amperes  on  a  wave 
length  of  425  meters,  and  the  oscillation 
transformer  is  made  with  edgewise  wound 
copper  strip,  a  type  with  which  you  are 
all   familiar,  and  which  is  clearly  shown 


any  question  whatever  but  that  Station  9ZF 
is  well  entitled  to  the  prize. 

Since  holding  the  Washington's  Birthday 
Relay,  which  you  will  all  remember  was 
held  in  the  interest  of  preparedness,  with 
instructions  to  all  sending  stations  to  in- 
terest all  wireless  amateurs  in  the  United 
States  Radio  Coast  Reserve,  Station  9ZF 
worked  the  hardest  for  recruits  of  any  sta- 
tion in  the  United  States. 

We  have  radio  clubs  in  the  United  States 
of  minor  importance,  which  seem  to  think 
that  they  were  the  only  ones  that  had  a 
divine  right  to  exist,  who  have  not,  with 
all  their  membership,  done  as  much  good 
work  in  enlisting  the  amateurs  under  the 
Navy  Department  for  coast  reserve  work 
as  Station  9ZF. 

All  of  the  stations  have  been  closed  by 
the  Navy  Department,  on  account  of  the 
war,  for  the  period  of  war,  and  we  believe 
it  will  be  some  little  time  before  all  of  us 
are  working  again.  In  order  that  your 
interest  will  not  lag  in  wireless  work,  and 
for  the  benefit  of  the  many  amateurs  who 
have  enlisted  thruout  the  country  and  are 
now  assigned  to  the  various  warships,  we 
will  continue  these  write-ups  each  month, 
with  something  of  interest  to  them,  and 
something  to  remind  them  of  home  and 
(Continued  on  page  143) 


108 


THE   ELECTRICAL  EXPERIMENTER 


June,  1917 


Notice  to  All  Radio  Readers 

As  most  of  our  radio  readers  arc  undoubtedly  azvare,  the  U.  S.  Government  has  decided  that  all  Amateur  Wireless  Stations, 
whether  licensed  or  unlicensed,  or  cquipt  for  receiving  or  transmitting,  shall  be  closed. 

This  is  a  very  important  consideration,  especially  to  those  who  are  readers  of  THE  ELECTRICAL  EXPERIMENTER, 
for  the  reason  that  we  desire  to  continue  to  publish  valuable  articles  in  the  zvireless  art  from  time  to  time,  and  which  may 
treat  on  both  transmitting  and  receiving  apparatus.  In  the  first  place,  there  arc  a  great  many  students  among  our  readers 
who  will  demand  and  expect  a  continuation  of  the  usual  class  of  Radio  subjects,  which  we  have  publisht  in  the  past  four 
years,  and  secondly,  there  will  be  hundreds  and  even  thousands  of  new  radio  pupils  in  the  various  naval  and  civilian  schools 
thruout  the  country,  zvho  will  be  benefited  by  up-to-date  wireless  articles  treating  on  both  the  transmitting  as  well  as  receiv- 
ing equipment. 

Therefore,  and  in  view  of  the  foregoing  explanation,  we  feel  sure  that  every  reader  will  thoroly  understand  that  altho 
articles  on  transmitting,  as  well  as  receiving,  apparatus  may  appear  from  time  to  time  in  these  columns,  he  is  not  permitted  to 
connect  up  any  radio  apparatus  whatsoever  to  any  form  of  aeriah — The  Editors. 


The  Naval  Radio  Operator 


SCHOOLS  are  established  at  the  Navy 
Yards  at  New  York  and  San  Fran- 
cisco for  the  purpose  of  furnishing 
Radio  Electricians  for  the  fleet 
from  the  enlisted  personnel  of  the 
Navy.  After  the  required  sea  serv- 
ice has  been  performed  such  electricians 
are  transferred  to  shore  duty  at  Naval 
Radio  stations  and  other  places. 

The  electrical  branch  of  the  schools  is 
divided  into  two  parts.  One  branch  for 
general  electricians  and  the  other  for  radio 
(wireless).    Applicants  capable  of  passing 


radio  telegraphy  may  be  enlisted  as  lands- 
men for  Radio  Electrician.  The  applicant 
must  be  able  to  take  dictation  at  the  speed 
of  twenty-five  words  per  minute  and  pass 


centage  and  square  root.  Testimonials  as 
to  the  good  character  and  skill  of  the 
applicant  as  an  operator  must  be  presented 
either  from  a  former  employer  or  from 
the  principal  of  a  school  where  the  appli- 
cant has  been  a  student  of  radio  or  teleg- 
raphy. The  applicant  must  be  able  to 
receive  about  twenty  words  a  minute. 

In  addition  to  the  above,  men  holding 
commercial  radio  licenses  and  who  pass  an 
additional  examination  at  the  Electrical 
School,  Navy  Yard,  New  York,  or  Mare 
Island,  Cal.,  may  be  enlisted  as  electricians 


Future  Naval  Radio  Men  Learning  How  to 
Measure   Length  and   Frequency  of  Etheric 
Waves. 


the  examination  are  enlisted  as  landsman 
for  electrician  (either  general  or  radio) 
and  are  detailed  for  a  course  at  the  Elec- 
trical School.  The  pay  of  landsman  for 
electrician  is  $17.60  per  month  while  under 
instruction  and  in  addition  he  is  furnished 
with  a  complete  outfit  of  uniform,  board, 
lodging,  text  books,  tools,  and  materials 
with  which  to  work.  The  length  of  the 
course  is  about  eight  months.  Upon  com- 
pletion of  the  course  at  the  school  the 
men  who  are  qualified  are  given  the  rating 
of  electrician  third  class  (radio).  In  both 
courses  the  following  subjects  are  covered  : 
machine  shop  work,  electricity;  magnetism, 
alternating  currents,  dynamos,  motors,  and 
batteries.  It  also  embraces  the  principles 
and  management  of  radio  stations  and  in- 
stallations. The  general  course  covers  the 
application  of  electricity  to  shipboard  appli- 
ances. 

Competent  operators  of  the  Morse  code 
or  men   with   a    sufficient   foundation  in 


Top:— Naval  Radio  Operator  Handling  2  k.  w. 

Transmitter. 
Below:— One  of  the  Up-to-Rate  Radio  Sets 
Which  U.  S.  Naval  Operators  Learn  to  Handle 

a  creditable  examination  in  spelling  and 
penmanship. 

The  problems  in  arithmetic  include  mul- 
tiplication, division,  simple  proportion,  per- 


Operating  Room  of  Radio  Class  at  the  Navy 
School,  Brooklyn,  New  York. 

third  class  (radio).  In  both  cases,  whether 
enlisted  as  landsmen  for  electrician  or  elec- 
trician third  class  (radio),  the  regular 
course  at  the  school  follows.  The  oppor- 
tunity for  advancement  in  the  Naval  Radio 
Service  is  at  present  exceptionally  good 
and  is  worthy  of  consideration  by  every 
commercial  telegraph  and  radio  operator. 

The  pay  of  electricians  both  general  and 
Radio  is  as  follows :  Electricians  third 
class,  $33  per  month;  Electricians  second 
class,  $44  per  month;  Electricians  first 
class,  $55  per  month;  Chief  Electricians 
(acting  appointment),  $66  per  month,  and 
Chief  Electricians  (permanent  appoint- 
ment), $77  per  month.  This  pay  is  in- 
creased with  each  enlistment. 

The  present  policy  in  the  fleet  is  to  ad- 
vance electricians  third  class  (radio)  to 
electricians  second  class  at  the  end  of  a 
year  if  their  proficiency  mark  is  at  least 
3.2.  Electricians  third  class  (radio)  serve 
(Continued  on  opposite  page) 


June,  1917 


THE  ELECTRICAL  EXPERIMENTER 


109 


NEW  RADIO  TRANSMITTER  FOR 
U.  S.  "MOSQUITO"  FLEET. 

The  accompanying  photograph  shows  a 
complete  radio  transmitter  operated  from 


One    of  the    Latest    Designs   of  Ex- 
tremely   Compact   and    Light  Weight 
Radio    Outfits     Intended     for  "Mos- 
quito" Fleet  Service. 


a  current  derived  from  a  storage  battery. 
It  was  designed  for  supplying  the  mos- 
quito fleet  with  an  efficient  low  power 
transmitting  outfit. 

This  outfit  was  developed  by  A.  B.  Cole, 
a  New  York  radio  engineer.  It  consists 
of  a  quenched  spark  gap  of  the  open  air 
type  which  is  mounted  on  the  panel.  The 
sparking  surface  consists  of  two  large  spe- 
cial alloyed  discs.  The  gap  is  excited  by 
a  spark  coil  of  unique  design ;  this  is  placed 
behind  the  panel,  its  interrupter,  which  is 
of  the  independent  type,  being  stationed  on 
the  front  of  the  panel  and  visible  on  the 
center  right.  The  oscillating  circuit  con- 
sists of  the  usual  arrangements ;  namely,  a 

on  the  large  vessels  and  Electricians  sec- 
ond class  are  sent  in  charge  of  the  installa- 
tion on  destroyers  and  gunboats.  Men  who 
have  served  two  years  at  sea,  in  radio, 
and  who  have  advanced  to  second  class 
are  eligible  for  shore  duty.  The  pay  and 
allowances  and  retired  pay  of  the  Navy, 
and  the  fact  that  all  men  get  shore  duty, 
makes  the  Naval  Radio  Service  more  at- 
tractive than  that  of  the  commercial  ser- 
vices. A  comparison  of  the  two  pays  and 
allowances  in  the  Naval  Radio  and  Com- 
mercial Radio  favors  the  former. 

The  physical  and  moral  qualifications  re- 
quired_  for  entrance  to  the  Naval  Service 
apply  in  all  respects  to  these  branches.  If 
the  recruit  is  unable  to  complete  the  course 
of  instruction  at  the  Electrical  School  be- 
cause of  incompetency  or  inaptitude  he  will 
be  transferred,  if  he  desires,  to  such  rating 
in  the  general  service  as  he  is  qualified  to 
fill  or  he  will  be  discharged  from  the  Navy 
for  inaptitude. 

(Continued  on  page  153) 


high  tension  glass  condenser  and  aerial  in- 
ductance. A  transfer  switch  is  also  pro- 
vided for  permitting  the  receiving  and 
transmitting  instruments  to  be  connected 
at  any  time  desired.  This  is  shown  in 
the  upper  right  hand  corner.  A  hot  wire 
ammeter  is  also  furnished,  and  this  is 
seen  in  the  upper  center  of  the  panel. 

The  three  plugs  at  the  bottom  are  used 
for  several  purposes ;  the  left  hand  one  is 
employed  for  connecting  the  receiving  in- 
struments with  the  aerial ;  the  center  one 
connects  the  key  with  the  primary  of  the 
coil  and  battery,  and  the  right-hand  plug 
links  the  storage  battery  with  the  supply 
source.  The  plug  at  the  upper  left  hand 
corner  is  used  for  connecting  the  power 
source  with  the  test  buzzer  of  the  receiving 
set.  A  set  of  binding  posts  are  furnished 
for  connecting  the  aerial  and  ground  with 
the  set,  and  these  are  seen  at  the  upper 
part  of  the  panel,  each  being  fitted  with 
the  proper  name-plate. 

During  some  recent  tests,  the  outfit  has 
proven  to  be  very  efficient. 


THE    JAPANESE    T.    Y.  K. 
RADIOPHONE  SYSTEM. 

Among  the  early  distinguished  workers 
in  radiophony  we  find  that  Messrs.  Wichi 


The  Simple  Connections   Used   in  the 
Japanese    "T.    Y.     K."  Radiophone 
System. 

Torikata,  E.  Yokoyama  and  M.  Kitamura 
of  Japan  have  done  very  notable  work 
in  this  direction,  and  the  system  which 
they  have  evolved  is  a  radio  frequency 
spark  system  of  unique  design,  which  we 
herewith   describe    in  detail. 

The  complete  equipment  is  shown  in 
the  photograph  and  resembles  very  much 
an  ordinary  standard  "wall  telephone." 
The  transmitting  apparatus  outside  the 
generator  is  enclosed  within  the  top 
cabinet,  while  the  bottom  one  contains 
the  receiving  instruments  and  aerial  con- 
trol switch.  The  direct  current  rotary 
converter  is  seen  standing  on  the  floor. 
It  runs  on  a  110-volt  direct  current  source, 
and  delivers  500  volts  D.  C.  for  the  arc. 
Protective  resistances  and  choke  coil  are 
used,  and  these  are  mounted  on  a  sepa- 
rate base ;  they  are  seen  below  the  in- 
strument proper. 

The  transmitting  equipment  consists  of 
a  specially  constructed  arc,  its  electrodes 
consisting  of  iron  and  brass.  The  dis- 
tance between  the  stationary  and  movable 
electrodes  are  automatically  controlled 
by  means  of  an  electro-magnet  so  ar- 
ranged as  to  adjust  the  arc  terminals  in 
order  to  keep  the  oscillatory  condition 
operative.  This  arc  is  operated  in  the 
open  air  and.  the  same  is  mounted  on  top 
of  the  transmitting  cabinet.  Its  connec- 
tions are  made  thru  the  control  electro- 
magnets of  the  cquilibrator,  as  indicated  in 
the  wiring  diagram.     The  movable  elec- 


trode G  is  controlled  by  an  armature  H, 
which  is  acted  upon  by  the  electro-magnet. 
The  contact  I,  is  broken  as  soon  as  the 
arc  has  properly  started.  This  break  of 
current  at  I,  is  due  to  the  decrease  of 
the  arc  resistance  which  permits  a  large 
steady  flow  of  current  thru  the  coil,  con- 
sequently attracting  the  contact.  The  arc 
is  shunted  with  the  usual  type  of  oscil- 
latory circuit,  P.V.C.,  namely,  the  primary 
of  an  oscillation  transformer,  which  in- 
ductance is  controlled  by  means  of  the 
side  switch  on  the  left  of  the  transmitting 
cabinet.  A  variable  high-tension  condenser 
is  also  mounted  in  the  same  cabinet  and 
its  capacity  is  varied  by  means  of  a  multi- 
ple-point switch,  indicated  on  the  front. 
An  ordinary  carbon  microphone  is  linked 
in  the  ground  circuit  of  the  secondary  of 
the  oscillation  transformer,  as  shown  in 
the  wiring  diagram.  This  microphone  is 
stationed  on  a  movable  bracket  on  the 
front  of  the  cabinet. 

The  receiving  equipment  is  inclosed  in 
the  lower  compartment  and  consists  of  a 
standard  loose  coupled  receiver,  with  a 
crystal  detector.  This  is  placed  in  a  metal 
housing  equipt  with  a  metal  door,  seen 
on  the  left  of  the  case.  Adjusting  the 
crystal  is  performed  by  a  vertical  rod  pro- 
truding from  the  top  cover.  Two  variable 
condensers  are  used  and  these  are  mounted 
on  top,  while  the  coupling  of  the  primary 
and  secondary  is  varied  by  turning  the 
front  knob.  A  change-over  switch  is  sup- 
plied for  connecting  the  receiving  and 
transmitting  instruments  whenever  de- 
sired, and  the  control  handle  for  the  same 
is  seen  at  rear,  left-hand  corner  of  the 
lower  cabinet.  The  primary  switch  is 
mounted  on  the  left. 

Excellent  results  were  obtained  with  this 
system,  and  a  number  of  sets  have  been 
installed  in  several  Japanese  land  and  boat 


The  Japanese  "T.  Y.  K."  Wireless  Phone 
System  Is  One  of  the  Simplest  and  Most 
Efficient  Ever  Devised.  It  Greatly  Re- 
sembles the  Familiar  "Wall"  Type  Tele- 
phone. 

stations.  The  efficiency  in  watts  per  mile 
of  talking  range  is  remarkably  high.  Also 
the  design  of  the  complete  equipment  is 
marked  by  distinctive  simplicity. 


110 


THE  ELECTRICAL  EXPERIMENTER 


June,  1917 


Remarkable  Radio  Outfit  Built  By  German  Spy 


A LITTLE  black  box  of  mystery, 
seized  recently  by  the  police  in  the 
belief  that  it  was  nothing  more 
than  a  modern  adaptation  of  a  time 
worn  contrivance  for  swindling  un- 
sophisticated persons  out  of  their  savings, 


U.  S.  Government 
and  Police  Experts 
Were  Much  Sur- 
prised to  Find  That 
the  Cabinet  Here 
Shown,  Which  Was 
Recently  Seized 
with  Max  Wax,  a 
German  Spy,  Was 
Capable  of  Receiv- 
ing Secret  Radio 
Messages  from 
Germany. 


was  revealed  as  a  clever  wireless  telegraph 
outfit,  capable  of  receiving  messages  from 
as  far  away  as  Berlin. 

Police  and  government  experts  who  ex- 
amined the  mechanism  in  the  box  declared 
it  to  be  as  perfect  in  construction  as  any 
they  ever  had  seen.  It  is  (or  was)  the 
property  of  Max  Hans  Ludwig  Wax,  a 
German  citizen,  and  graduate  of  the  Uni- 
versity of  Berlin.  Wax,  as  soon  as  he 
found  the  police  had  learned  the  real  nature 
of  the  intricate  contents  of  the  box,  as- 
sumed an  air  of  stolid  indifference,  denied 
he  knew  the  box  could  lie  of  service  either 
in  sending  or  receiving  telegraph  messages 
or  that  he  knew  anything  of  telegraphy,  and 
asserted  that  apparently  useless  bits  of  par- 
aphernalia contained  in  the  box  had  been 
placed  there  by  him  merely  to  make  the 
contrivance  "look  pretty." 

Then,  the  police  say,  Wax  informed  pros- 
pective dupes  that  the  little  black  box  con- 
tained machinery  devised  by  German  scien- 
tists for  reproducing  American  banknotes 
and  currency  bills.  If  he  would  place  a  one- 
thousand  dollar  bill  in  the  "press"'  inside  the 
box  the  contrivance  would  print  ten  dupli- 
cates of  that  bill.  It  then  was  the  duty  of 
the  "loyal''  German,  the  police  say  they 
were  informed,  to  pass  the  spurious  notes 
off  for  American  gold,  so  that  eventually 
this  country  would  be  flooded  with  counter- 
feit notes  and  persons  loyal  to  Germany 
would  be  in  possession  of  most  of  this 
country's  gold. 

Just  after  Wax  was  arrested  the  police 
learned  that  he  had  left  the  box  in  a  ma- 
chine shop  in  New  York  City.  The  police 
finally  located  the  box  in  a  trunk  which 
they  said  was  equipt  with  a  false  bottom. 
It  was  not  until  Sergeant  Pierce,  in  charge 
of  the  police  wireless  station,  rigged  up  as 
part  of  the  scheme  for  military  defence 


by  Arthur  Woods,  Police  Commissioner, 
looked  at  the  contrivance  that  it  was  recog- 
nized as  a  genuine  and  extremely  effective 
portable  wireless  outfit. 

The  box  is  about  two  and  a  half  feet 
square.   It  is  covered  with  black  enamel  and 
has  silver  handles  and 
^mmm— — — j         brass   hinges  and 
BBHUfck.   S       clasp.     It  must  have 
Kkl     cost  at  least  $800,  ac- 
|j        cording    to    the  esti- 
K~3m        mate  of  experts. 
•jffjBlB  •         As    soon    as  Ser- 
PMErBHHBI  ¥  .       geant    Pierce  recog- 
8™     nized  the  use  to  which 
the    queer  arrange- 
ment  might   be  put 
the  outfit  was  rigged 
up,  its  batteries  were 
set  in  motion,  and  in 
a  moment  the  hissing 
sounds  and  sputtering 
and    flashing  sparks 
that  attend  the  opera- 
tion of  a  wireless  out- 
fit were  in  evidence. 

Wax  persisted,  de- 
spite the  effectiveness 
of  this  demonstra- 
tion, in  his  assertion 
that  the  batteries, 
tiny  dynamo  and  in- 
tricate coils  were 
placed  in  the  box  by 
him  to  make  the  ap- 
paratus "look  pretty." 
Eventually  he  said  he 
intended  to  use  them 
to  give  color  to  a  mo- 
tion picture  scenario 
he  intended  to  write. 

Persistent  question- 
ing, however,  drew 
from  Wax,  according 
to  the  police  state- 
ment, the  admission  that  he,  having  bought 
the  materials,  the  box  and  its  out'fit  were  put 
together  for  him  by  a  seaman  on  board  one 
of  the  interned  German  ships  lying  at  Ho- 
boken.  He  refused  to  reveal  the  identity 
of  the  man,  asserting  he  knew  him  only  as 
"Frank"  and  had  met  him  only  a  few  times. 

When  the  examination  of  Wax  had  pro- 
ceeded that  far  L.  R.  Krum,  chief  radio 
officer  of  the  federal  government  for  the 
New  York  district,  arrived  at  Police  Head- 
quarters. He  examined  the  machinery  con- 
tained in  the  box  carefully  and  then  verified 
Sergeant  Pierce's  declaration  that  it  was  a 
wireless  outfit  of  great  strength.  He  agreed 
with  Sergeant  Pierce  that  the  apparatus 
was  easily  capable  of  receiving  messages 
from  as  far  away  as  Berlin.  Both  experts, 
however,  declared  the  apparatus  probably 
could  not  be  used  to  send  a  message  much 
farther  than  one  hundred  miles. 

Despite  the  readiness  with  which  Mr. 
Krum  and  the  police  wireless  operators 
were  able  to  set  the  wireless  outfit  in  mo- 
tion, many  contrivances  in  the  box  were  a 
mystery  to  them.  It  appeared  as  if  there 
were  three  sets  of  batteries,  where  only  one 
was  necessary.  The  operators  exprest  the 
belief,  however,  that  any  one  of  the  three 
battery  sets  might  have  been  connected  with 
the  rest  of  the  apparatus,  so  that,  even  if 
two  batteries  failed,  there  still  would  be 
power  to  keep  the  contrivance  in  operation. 

The  only  incomplete  thing  about  the  out- 
fit was  that  the  police  were  unable  to  find  a 
sending  key  and  a  transformer,  both  of 
which  would  be  necessary  if  the  machine 
were  to  be  used  for  sending  wireless  mes- 
sages. Wax,  however,  is  described  by  per- 
sons who  stayed  in  the  house  where  he  lived 
as  having  been  in  the  habit  of  carrying  a 
small  hand  grip.  The  grip  has  not  yet  been 
found. 


After  the  police  were  satisfied  of  the  na- 
ture of  the  equipment  in  the  box  they  asked 
Wax  to  operate  it.  He  fingered  several 
parts  of  the  mechanism  for  a  moment  or 
two  and  finally  succeeded  in  causing  a  short 
circuit,  which  effectually  put  the  whole  thing 
out  of  commission.  The  damage,  however, 
can  be  repaired  easily. 

In  the  examination  of  Wax  the  police 
drew  from  him  the  statement  that  he  came 
to  this  country  from  Germany  in  June, 
1914. 

He  denied  he  had  served  in  the  German 
army,  asserting  he  was  rejected  for  mili- 
tary service  because  he  had  a  weak  heart. 
Dr.  Baker  and  Dr.  Hamilton,  police  sur- 
geons, were  called  in  to  examine  the  pris- 
oner. They  pronounced  him  an  almost 
perfect  physical  specimen  and  said  there 
was  no  indication  that  he  ever  had  suffered 
from  heart  disease. 

Considerable  interest  was  manifested  by 
the  police  and  federal  investigators  in 
papers  and  letters  found  in  Wax's  posses- 
sion. They  declared  some  were  written  in 
code.  All  of  them  were  in  duplicate.  One 
of  the  papers,  according  to  the  police,  was  a 
draft  for  $12,000  and  another  was  for  2,300 
marks.  The  latter  was  drawn  on  the 
Deutsche  Bank,  of  Berlin.  It  was  declared 
by  the  police  that  Wax  received  some  of 
these  papers  thru  the  office  of  the  German 
Consul  in  this  city  several  weeks  ago.  The 
money,  the  police  said  they  learned,  was  sent 
to  _  Wax  by  relatives  in  Germany,  who  the 
prisoner  declared  were  both  wealthy  and 
influential  there. 


ELECTRICITY  REDUCES  FIRE 
HAZARD. 

One-fourth  of  all  the  fires  occurring  in 
Waterbury, .  Conn.,  for  a  year  might  have 
been  avoided  by  the  use  of  electricity, 
according  to  the  report  of  Fire  Chief 
Heitman. 


A  NEW  VACUUM  CURRENT  GAGE 
FOR  RADIO. 

Herewith  we  present  the  vacuum  am- 
pere gage,  a  new  Marconi  device. 

The  demand  for  a  small,  sensitive,  ro- 
bust instrument '  suitable  for  use  equally 
on  alternating  and  continuous  current  cir- 
cuits is  not  new,  and  inventors  have  made 
many  attempts  to  satisfy  it. 

The  instrument  is  designed  primarily  as 
a  maximum  current  gage  to  indicate  the 
condition  of  syntony  in  wireless  circuits, 
and  may  be  employed  as  a  substitute  for  a 
ihcrmo- junction  and  galvanometer  com- 
bination in  the  measurement  of  wave 
lengths  and  decrement.    The  principle  in- 


tloir^Spring 


Support 


fi/omenk 


By  Placing  the  Delicate  Moving  Parts  of 
This  High  Frequency  Current  Gage  in  an 
Evacuated  Bulb  the  Action  is  Made  More 
Stable  and  Reliable.  It  Can  Be  Used  with 
a  Wave  Meter  to  Measure  the  "Decre- 
ment." 

volved  is  that  of  the  bifilar  suspension,  one 
pair  of  the  filament  ends  being  fixt,  and  the 
other  pair  attached  to  a  pivoted  arm,  the 


June,  1917 


THE   ELECTRICAL  EXPERIMENTER 


111 


rotation  of  which  is  controlled  by  a  spring 
acting  against  the  tension  of  the  filaments. 
When  a  current  passes  thru  the  filaments, 
heating  them  and  causing  them  to  elongate, 
the  arm  takes  up  a  new  position  and  the 
angular  displacement  as  indicated  on  the 
scale  is  a  measurement  of  the  current. 

The  movement  is  enclosed  in  a  glass  bulb 
exhausted  of  air.  The  sensitiveness  is  thus 
greatly  increased,  and  the  movement  pro- 
tected against  damage  and  preserved  from 
dust  or  corrosion. 

The  drawing  shows  quite  clearly  the  con- 
struction of  the  little  instrument,  which  is 
made  up  in  such  a  way  as  to  resemble  an 
electric  lamp.  In  one  form  the  bulb  is 
attached  to  a  brass  cap  with  projecting 
pins  identical  with  that  used  on  standard 
English  lamp  bulbs,  and  the  size  of  the 
instrument  can  be  gaged  by  noticing  this 
feature  in  the  drawing. 

The  variation  in  zero  which  is  character- 
istic of  hot  wire  instruments  in  general  is 
negligible  in  this  type  of  instrument,  and 
the  natural  damping  renders  the  move- 
ment especially  dead-beat. 

The  instrument,  suitably  calibrated,  may 
also  be  used  as  a  low  reading  volt-meter  or 
ammeter,  or  as  a  shunted  ammeter.  The 
normal  resistance  of  the  commercial  type 
of  vacuum  instrument  is  approximately  12 
ohms. 

Enclosing  the  working  parts  in  a  vacuum 
has  enabled  the  makers  to  place  on  the 
market  an  instrument  which  should  prove 
of  great  general  utility  on  account  of  the 
fact  that,  at  a  reasonable  cost,  it  is  pos- 
sible to  provide  the  means  of  measuring 
direct  and  alternating  currents  of  the  or- 
der of  .01  amp.,  without  sacrificing  any 
robustness  of  construction.  The  small  size 
makes  it  a  matter  of  no  particular  diffi- 
culty to  insert  the  instrument  in  a  circuit 
where  no  previous  provision  has  been  made 
for  a  measuring  instrument. 

With  a  wave  meter  using  the  new  vacu- 
um gage  the  wave-length  of  the  primary 
circuit  of  a  1^2-kw.  set  can  quite  easily  be 
read  when  the  wave  meter  is  held  with  the 
plane  of  its  inductance  coils  parallel  to 
that  of  the  primary  of  the  oscillation  trans- 
former at  a  distance  of  two  to  three  feet. 
The  noise  of  the  spark,  which  often  hin- 
ders the  reading  of  a  wave  meter  by  means 
of  a  crystal  and  telephones,  in  the  case  of 
the  vacuum  gage  gives  no  trouble,  as  the 
variable  condenser  has  simply  to  be  rotated 
until_  the  pointer  of  the  gage  gives  the 
maximum  reading.  In  this  way  circuits 
can  be  tuned  rapidly  as  well  as  accurately. 


MISS  WINIFRED  DOW  A  RADIO 
ENTHUSIAST. 

Herewith  find  picture  of  my  radio  ex- 
perimental outfit.     My  receiving  set  con- 


sists of  a  Murdock  variable  condenser,  ai 
Audion  and  variometer. 

With  this  set  I  hear  the  calls  of  KPH 
KPA;  NPC;  NPE  and  of  course  all  Ama 
teurs  in  this  vicinity. 

At  the  present  ......                          ,.  ,      .  „ 

t  „„,  Mlss  Margaret  L.  Campbell,  of  Rock- 
time  1  am  Using  portj  Mass.,  Has  Long  Been  a  Radio 
only  a  spark  COll  Enthusiast  and  Has  Operated  the  Ap- 

and  dry  cells  for  Parj?tus    Sh°w"  _  °n    Frequent  Trips 

.  i.  .       ,      ,  Made   on    Her    Father's    Yacht.  She 

transmitting  DUt  Has  Achieved  a  Distinct  Success  with 

have  a  1  kilowatt  Her  Station,   Having  Become  Thoroly 

set    nearly    com-  Conversant   with    All    Radio  Matters. 

plete. 

I  thank  you  in 
advance  for  the 
interest  you  have 
taken.  Wirelessly 
yours,  Winifred 
Dow,  Tacoma, 
Wash. 


"THE  CRUISE"— A  RADIO  STORY. 
By  MARGARET  L.  CAMPBELL. 

Early  in  August,  1916,  I  transferred  my 
wireless  set  from  my  radio  station  to  my 


There  are  lots 
of  worse  jobs 
than  that  of  Ra- 
dio operator  for 
Uncle  Sam.  Be- 
sides, he  pays 
you  while  learn- 
ing. Why  not  in- 
quire about  it  ? 
Both  women  and 
men  are  eligible. 


MRS.  CANDLER  AN  ABLE  RADIO 
OPERATOR. 

Mrs.  Candler  of  St.  Marys,  Ohio,  says, 
"I  surely  am  very  much  interested  in  wire- 
less and  not  only  interested  but  have  been 
operating  our  set  ever  since  it  has  been 
in  existence.  I  now  hold  a  first  grade  com- 
mercial license.  The  first  photo  of  our  set 
was  sent  you  last  year  by  '9XE'  and  ap- 
peared in  the  Experimenter  in  connection 
with  the  report  of  the  Washington's  Birth- 
There  Is  Now  an  Opportunity 
for  All  Radio  Women.  One 
of  the  Best  Qualified  Opera- 
tors Is  Mrs.  Chas.  Candler, 
of  St.   Marys,  Ohio. 


day  Relay  in  the  May,  1916,  issue.  This 
year  our  station  (8NH")  again  took  prom- 
inent part  in  the  Presidential  Relay,  being 
a  prize  winner.  We  have  been  subscrib- 
ers to  the  Electrical  Experimenter  for 
more  than  a  year." 


Among  the  Girls  "Radio"  Has  Now  Become 
a  Promising  Vocation.     At  Least  Miss  Wini- 
fred   Dow,    of    Tacoma,    Wash.,    Seems  to 
Think  So. 


PHILADELPHIA'S     NEW  RADIO 
STATION  WILL  SEND  THREE- 
FOURTHS  WAY  AROUND 
WORLD. 

Preliminary  wor£  on  construction  of  one 
of  the  most  powerful  wireless  stations  in 
the  world  has  begun  at  the  Philadelphia 
Navy  Yard,  according  to  an  official  an- 
nouncement made  recently.  The  construc- 
tion of  a  hangar  which  will  house  eight 
battle  hydroairplanes  also  is  under  way. 

The  new  wireless  station  will  have  a 
sending  radius  of  approximately  three- 
fourths  of  the  distance  around  the  globe, 
making  possible  direct  communication  with 
the  Philippines  and  other  insular  possessions 
of  the  United  States.  The  aerial  structure 
will  be  more  than  700  feet  high. 


father's  new_  sixty  foot  yacht,  the  Wa- 
liama.  She  is  a  flush  deck  cruiser  with 
all  modern  improvements  and  powered 
with  a  large  four-cycle  gasoline  engine. 
She  also  has  two  masts  about  thirty-five 
feet  apart,  which  I  used  to  support  my 
aerial.  There  is  a  large  cabin,  ten  by  twelve 
feet  in  size,  in  which  I  installed  my  trans- 
mitting and  receiving  apparatus,  which  con- 
sists of  a  two  inch  spark  coil,  two  Leyden 
jars,  helix,  spark  gap  and  key.  Also,  two 
variable  condensers,  loose  coupler,  tuning 
coil,  loading  inductance,  Ferron,  galena  and 
silicon  detectors  mounted  upon  a  movable 
cabinet. 

One  of  the  interesting  cruises  made  last 
summer  was  with  a  company  of  Marine 
Boy  Scouts  of  which  my  father  is  the 
fa  commander.  We  sailed  along  the  coast 
of  Massachusetts  Bay,  visiting  vari- 
ous harbors  and  spending  several  days 
in  Marblehead  harbor  during  the  fes- 
tivities of  "Marblehead  Week,"  when 
the  great  racing  events  of  that  notable 
yachting  center  are  held. 
The  harbor  was  filled  with  yachts  of  all 
types  and  age;  from  the  majestic  steam 
yacht  of  the  millionaire  to  the  small  sailing 
dory  of  some  aspiring  youth.  I  was  sur- 
prised to  find  how  few  of  these  boats  were 
equipt  with  wireless  apparatus,  also  how 
few  of  them  so  equipt  appeared  to  be  using 
their  apparatus  or  even  listening  in.  I 
held  conversation  with  some  interested 
amateurs  on  shore. 

We  did  not  send  or  receive  any  "S.O.S." 
calls,  but  did  have  occasion  to  render  timely 
assistance  to  a  motor  boat  whose  engine 
had  broken  down  out  at  sea  and  towed 
her  to  a  place  of  safety  before  a  severe 
thunder  storm  broke  upon  us. 

I  might  say  that  I  detected  little  differ- 
ence in  the  workings  of  my  apparatus 
aboard  the  boat  as  compared  with  the 
same  on  land. 

I  found  my  set  to  be  of  the  greatest 
service  in  the  evening  when  the  crew  gath- 
ered about  to  get  the  time  signals  and  the 
news  of  the  day. 


WIRELESS  TELEGRAPHY  ON 
BRITISH  SHIPS. 

By  an  Order  in  Council,  issued  on  July 
28  last,  every  British  ship  of  3,000  tons 
gross  or  upwards  is  required  to  have  a 
wireless  installation. 


112 


THE  ELECTRICAL  EXPERIMENTER 


June,  1917 


The  Marconi  Type  "106"  Tuner 


THE  receiver  consists  of  a  type  "106'' 
tuner  and  a  crystal  detector.  This 
receiver  consists  of  a  variable  induct- 
ance primary   circuit.     One   end   of  this 
inductance  is  connected  to  the  antenna  thru 


By  WORTH  MacKNIGHT 

The  switches  marked  Transformer  Pri- 
mary are  for  the  purpose  of  varying  the 
amount  of  inductance  in  the  aerial  circuit. 
The  switch  marked  Units  varies  the  induc- 
tance in  one-turn  steps.   The  switch  marked 


F/g.l 


Front  View  of  the  "Marconi"  Type  106  Radio  Receiving  Cabinet. 

Will  Find  It  Beneficial  to  Study   It  Thoroly. 

the  antenna  switch.  The  other  end  of  the 
inductance  is  connected  to  the  ground  thru 
a  variable  condenser,  which  can  be  short- 
circuited  or  thrown  into  circuit  at  will.  The 
secondary  circuit  is  so  constructed  that  its 
inductance  may  be  varied,  and  also  its  in- 
ductive relation  with  the  primary  circuit 
can  be  changed.  A  variable  condenser  is 
provided,  which  permits  a  variation  of  wave 
length  and  also  the  variation  of  the  ratio 
capacity  to  the  inductance,  while  maintain- 
ing the  same  wave  length.  A  battery  and 
potentiometer  is  provided  which  permits 
controlling  the  current  thru  the  detector.  A 
pair  of  head  telephones  is  used  for  receiv- 
ing the  signals.  A  buzzer  is  supplied  which 
permits  the  local  excitation  of  this  receiver, 
so  as  to  determine  its  condition  of  sensi- 
tiveness. A  battery  furnishes  current  for 
both  the  detector  and  buzzer. 

Fig.  1  is  a  front  view  of  the  type  "106" 
tuner  and  shows  the  exact  position  of  the 
different  switches  and  parts  for  its  opera- 
tion. 


Radio  Students 


aerial  is  connected  to  one  terminal  of  the 
inductance,  so  that  by  varying  the  trans- 
former primary,  a  greater  or  less  amount  of 
inductance  can  be  inserted  between  the. 
aerial  and  ground.  This  either  increases  or 
decreases  the  natural  period  of  the  primary 
or  aerial  circuit.  It  is  necessary,  therefore, 
to  make  these  adjustments  to  bring  the  cir- 
cuit in  tune  with  the  received  signals.  If 
the  wave  length  of  the  received  signal  is 
shorter  than  that  of  the  aerial  circuit,  it  is 
necessary  to  insert  the  primary  condenser  in 
the  circuit.  This  has  the  effect  of  shorten- 
ing the  time  period  of  this  circuit.  The 
secondary  circuit  consists  of  a  variable 
condenser  marked  Secondary  Condenser, 
and  a  variable  inductance  marked  Trans- 
former Secondary. 

By  varying  either  the  transformer  sec- 
ondary switch  or  the  secondary  condenser, 
this  circuit  can  be  tuned  to  the  wave  length 
of  the  incoming  signals.  It  is  also  possible 
to  vary  the  ratio  of  capacity  to  inductance, 
while  maintaining  the  same  wave  length 
adjustment.  It  is  often  found  to  advantage 
to  vary  this  ratio.  The  handle  marked 
Coupling  is  for  the  purpose  of  varying  the 
inductive  relation  of  the  primary  circuit  and 
the  secondary  circuit.  After  these  circuits 
have  been  tuned  to  the  incoming  signals, 
the  coupling  should  be  varied  until  a  maxi- 
mum   response   is    found.      The  handle 


Front  View  of  "Marconi"  Type  106  Radio  Receiving  Cabinet,  Equipt  with  Mineral 
Detector  and   Loose  Coupler. 


fig.. 


Pofenf/ometer 


4"lwwv — -^ 


/ 

Buzzer 


Hook-Up  for  Complete  "Marconi"  Type  106  Receiving  Set,  Showing 
Inductively  Coupled  Test  Buzzer. 


Tens  varies  this 
inductance  in  ten- 
turn  steps.  The 
Primary  Conden- 
ser, when  in  zero 
position,  has  a 
minimum  capacity. 
If  this  condenser 
is  turned  beyond 
the  180  degree 
mark,  it  automati- 
cally short-circuits 
itself,  so  that  the 
aerial  circuit  will 
have  no  series  ca- 
pacity in  it.  The 
terminal  marked 
Aerial  is  connect- 
ed to  the  antenna 
switch.  The  ter- 
minal  marked 
Ground  is  connect- 
ed to  the  ground. 
When  this  primary 
circuit  is  connect- 
ed to  the  aerial  and 
ground  the  circuit 
is  as  follows :  The 


marked  Potentiometer  varies  the  current 
thru  the  crystal  detector.  The  detector  is 
situated  between  the  coupling  and  conden- 
ser handles.  A  switch  marked  Battery 'is 
provided,  so  that  the  crystal  may  be  used 
either  with  or  without  the  battery.  A  buz- 
zer is  mounted  on  the  front  of  the  panel 
and  is  operated  with  a  button  marked  Test. 
Terminals  are  provided  to  connect  to  the 
battery;  they  are  marked  Battery.  Two 
terminals  are  provided  for  connecting  in 
the  telephone  receivers,  and  are  marked 
Telephones. 

The  internal  as  well  as  the  external  con- 
nections of  this  receiver  are  shown  in  Fig. 
3.    Fig.  2  is  a  back  view  of  the  panel. 

This  hook-up  is  of  interest  to  all  radio 
amateurs  and  students  who  expect  some 
day  to  become  commercial  operators. 
Among  other  things,  note  that  the  buzzer 
test  is  linked  up  with  the  aerial-ground  cir- 
cuit inductively  by  a  two  coil  transformer. 
Note  how  the  secondary  coil  is  moved  in 
and  out  of  the  primary  by  a  rack  and  pinion 
arrangement,  giving  great  precision  to  the 
coupling  adjustments  as  well  as  rotary  con- 
trol. 


June,  1917 


THE   ELECTRICAL  EXPERIMENTER 


113 


The  How  and  Why  of  Radio  Apparatus 


r!f       Zinc  electrodes 

y. 


— ^x tond 


NO.  4— SPARK  GAPS. 

From*  lime  to  time  we  will  describe  one 
particular  instrument  used  in  either  the  ra- 
dio transmitting  or  receiving  set,  explain- 
ing just  how  it  works,  and  why.  We  have 
received  so  many  requests  from  new  read- 
ers asking  for  such  explanations,  that  we 
have  decided  to  publish  this  matter  in  serial 
form.  In  the  course  of  several  issues  all  of 
the  principal  transmitting  and  receiving  ap- 
paratus zvill  have  been  covered.  The  subject 
for  the  fourth  paper  is  the  SPARK  GAP. 

THE  spark  gap  forms  one  of  the 
most  important  parts  of  any  os- 
cillatory circuit,  and  this  proves 
particularly  so  in  radio  transmit- 
ting circuits,  where  everything 
must  be  designed  to  realize  the  utmost  ef- 
ficiency. This  means  careful  and  scientific 
design  at  every  turn,  and  it  takes  into  con- 
sideration such  important  topics  as  the 
proper  dissipa- 
tion of  the  heat 
produced  in  the 
gap ;  the  proper 
arrangement  o  f 
the  gap  to  give 
the  desired  tone, 
and  a  number  of 
other  vital  points. 

The  part  played 
by  the  spark  gap 
in  an  oscillatory 
circuit  is  to  allow 
the  condenser  in 
this  circuit  to 
charge  to  the  re- 
quired voltage, 
and  then  to  break 
down  and  permit 
the  charge  stored 
in  the  condenser, 
to  surge  back 
and  forth  across 
the  gap  in  the 
form  of  sparks, 
until  all  of  its 
energy  is  dissi- 
pated. For  sev- 
eral reasons  the 
ideal  spark  gap 
would  be  one 
which  would  in- 
sulate perfectly, 
or  be  11011  -  con- 
ducting during 
the  time  when 
the  condenser 
was  being 
charged, and  con- 
ducting perfectly, 

while  the  condenser  was  discharging. 

The  nearer  these  requirements  are  ful- 
filled in  any  spark  gap,  the  more  efficient 
will  this  piece  of  apparatus  perform  its 
function.  While  the  discharge  is  passing, 
the  resistance  of  the  gap  depends  upon 
two  factors :  the  resistance  increasing 
markedly  with  the  length  of  the  spark, 
and  decreasing  rapidly  with  the  oscillatory 
current,  amounting  with  a  half-inch  gap 
to  several  hundred  ohms  when  a  fraction 
of  an  ampere  passes,  and  but  a  small  frac- 
tion of  an  ohm  when  say  sixty  amperes 
flow  across  the  gap.  If  the  spark  length 
is  above  one-half  inch,  the  resistance  with 
the  same  oscillatory  current  flowing,  can 
be  taken  as  approximately  proportional  to 
the  spark  length.  However,  in  a  condens- 
er circuit,  the  quantity  of  electricity  is 
stored  up  in  the  condenser,  and  in  conse- 
quence, the  amount  of  oscillatory  current 
increases  with  the  spark  length.  Hence, 
we  find  two  conditions  working  against 
each  other,  as  regards  the  influence  of  the 
spark    length    on    the    spark  resistance. 


However,  we  can  increase  the  amount  of 
current  passing  thru  the  gap  without  in- 
creasing the  length  of  the  spark,  by  simply 
increasing  the  size  of  the  condenser,  and 
the  most  efficient  circuit  for  a  given  amount 
of  power,  is  that  in  which  there  is  a  mod- 
erate spark  length  with  a  large  condenser. 

When  the  condenser  has  been  fully 
charged,  the  spark  gap  breaks  down,  and  the 
gap  becomes  filled  with  metallic  vapor,  and 
for  the  time  being  forms  a  high  frequency 
alternating-current  arc.  The  conductivity 
of  the  spark  is  due  to  the  presence  of  me- 
tallic vapor  in  the  gap.  After  the  discharge- 
ceases,  and  if  this  metallic  vapor  is  not 
quickly  removed  from  the  gap,  the  insula- 
tion will  in  consequence  be  very  low  at 
the  time  that  the  condenser  is  passing  thru 
its  next  charging  period,  which  of  course 
occurs  in  a  small  fraction  of  a  second,  usu- 
ally. 

It  is  therefore  paramount  that  we  re- 


any  indefinite  time,  it  is  best  with  such 
non-synchronous  rotary  gaps,  to  provide  a 

stationary  electrode  "A,"  in  the  form  of  a 
segment,  having  a  pitch  equal  to  the  dis- 
tance between  two  of  the  rotary  electrode 
points. 

For  synchronous  rotary  gaps,  driven  by  a 
synchronous  A.C.  motor  or  by  mounting 
the  disc  on  the  same  shaft  with  the  motor- 
generator,  as  is  done  in  the  best  types  of 
commercial  radio  transmitting  sets,  the  fixt 
electrodes  need  not  be  any  larger  than  a 
single  electrode  point  on  the  rotary  disc. 

One  of  the  most  efficient  spark  gaps  used 
very  successfully  by  commercial  stations 
and  also  by  numerous  amateurs,  is  the 
quenched  gap  illustrated  at  Fig.  3.  This 
gap,  which  is  very  well  known  to-day,  is 
designed  on  several  important  basic  prin- 
ciples. The  foremost  of  these  desidera- 
tums  is  that  each  gap  shall  be  preferably 
not  over  1/100  of  an  inch  in  length,  and 
moreover,  that 


Coo/mg  Vanes 
SparAgap 


Spark  gap 


Zinc  Electrodes 
Threaded  in 


Trf  Sec 


Grooves  ■ 


fW>l        Cooling  ranges 


Fig.  2 

Segments,  fat    /Rotaru  plate 
j  (Plate  7 

•»>\i)!m//d/^ /Airtight  casing 
-  -     1Y  Adjustable 
bo//  bearings 


WIPE 


Cooling^ 
Vanes 


Cost  or  turned  plates 


F//.J  plate 


Ins u I.  coupling 

Mo/orshaf/ 
003'  '  spA  gap. 


Fig.  3 


Fig.  4 


Various  Styles  of  Radio 
Sets.    The  Rotary  Quenc 


Spark  Gaps  Which  Have  Been  Found  Efficie 
hed  Gap,  Fig.  4,  Is  One  of  the  Best  for  Small 
Operating  on  Low  Frequency  Circuits. 

move  this  vapor  completely  as  soon  as  pos- 
sible after  the  discharges  of  the  condenser 
have  ceased.  This  has  been  attempted  in 
various  ways  in  the  past,  such  as  by  pro- 
viding spark  gaps  having  large  cooling 
vanes  attached  to  the  spark  electrodes,  as 
in  Fig.  1,  and  also  by  causing  one  or  both 
of  the  spark  gap  electrodes  to  rapidly  ro- 
tate, so  as  to  constantly  refresh  the  air  in 
the  gap.  This  latter  condition,  which  is 
usually  met  by  arranging  a  number  of 
small  spark  electrodes  on  a  rotary  disc  at- 
tached to  the  shaft  of  a  motor,  or  to  the 
shaft  of  a  motor-generator  in  the  case  of 
synchronous  spark  gaps,  the  spark  being 
caused  to  jump  thru  the  air  between  the 
constantly  moving  electrodes,  and  one,  or 
more  fixt  electrodes  mounted  on  the  base 
of  the  spark  gap. 

Fig.  2  shows  a  non-synchronous  type  of 
spark  gap  in  which  the  speed  of  the  rotat- 
ing disc  bears  no  definite  relation  to  the 
frequency  of  the  alternating-current  in  the 
transformer  or  spark  coil.  As  a  spark  is 
apt  to  occur,  or  want  to  occur,  at  most 


the  gap  shall  be 
absolutely  air- 
tight. Further, 
not  over  1,000  to 
1,200  volts  should 
be  applied  to 
each  individual 
gap,  and  for  high- 
er voltage  a  suit- 
able number  of 
these  short  gaps 
are  placed  in  se- 
ries, as  shown  in 
the  illustration 
herewith ;  two 
gaps  being  adap- 
ted to  2,000  volts 
—  three  gaps  to 
3,000  volts,  etc. 
The  action  o  f 
this  gap  has  been 
described  at  some 
length  in  a  semi- 
technical  manner 
by  Mr.  Charles 
R.  Ballantine  in 
the  March,  1917, 
issue  of  The 
Electrical 
Experimenter. 
Briefly,  the  action 
of  the  gap  is 
based  upon  the 
fact  that  a  small 
quantity  of  air 
is  trapt  between 
the  spark  sur- 
faces separated 
by  a  mica  ring  of 
proper  thickness.  After  the  first  few  sparks 
have  past  the  oxygen  in  the  trapt  air  is 
burned  up,  resulting  in  a  partial  vacuum  in 
the  gap.  This  conduces  to  the  rapid 
quenching  thereafter  of  the  spark  dis- 
charges, due  to  the  condenser,  and  gives 
rise  to  a  very  ideal  set  of  conditions  for 
the  entire  radio  transmitting  circuit.  This 
is  because  the  oscillations  in  the  spark  gap- 
condenser  circuit  are  cut  off  after  the  first 
few  beats  or  sparks,  but  the  oscillations  in- 
duced in  the  aerial-ground  circuit  are  left 
free  to  oscillate  for  a  longer  period.  This 
prevents  the  reaction  of  free  oscillations  in 
the  spark  gap  circuit  upon  the  aerial  or 
secondary  circuit — a  condition  which  is  in- 
variably found  in  ordinary  radio  transmit- 
ters fitted  with  a  plain  fixt  spark  gap,  and 
a  condition  which  mitigates  seriously 
against  the  best  efficiency  of  such  an  equip- 
ment. The  quenched  spark  gap  usually 
consists  of  a  number  of  these  small  gaps 
as  above  described,  which  are  placed  in  a 
suitable  frame  so  that  considerable  me- 
(Continued  on  page  153) 


ten 


nt  for  Different  Types  of 
and  Medium  Power  Sets 


14 


THE   ELECTRICAL  EXPERIMENTER 


June,  1917 


BEING  cooped  up  in  a  flat,  late  years, 
I've  had  to  give  up  experimenting. 
Mine's  a  fine  flat,  as  flats  go— all 
modern  conveniences,  two  kinds  of 
cold  water  as  the  fellow  says,  and  a 
fire-escape  with  a  sparrow's  nest  on  it ; 
even  a  little  safe  let  into  the  wall,  big 


-Contacts 


ftg.i 


Fig.    1.     Attempt    No.    1    in    Electric  Clock 
Research  as  Tried  Out  by  the  Author — Did 
it  Work?     Read  the  Accompanying  Text  if 
You  Think  So,  Bugs. 

enough  to  hold  most  of  the  Wiff's  diamond 
tiaras  if  you  pack  'em  tight.  Yes,  it  has 
all  the  conveniences  but  one,  and  that's  the 
only  one  worth  having — a  workshop. 

The  nearest  I  can  get  to  it  now  is  read- 
ing the  good  old  Electrical  Experimenter. 
When  she  blows  in,  I  sop  her  up  from 
front  cover  to  back — every  word.  Adver- 
tisements and  all.  Well,  I'll  say  so;  and 
I'm  not  the  only  one  that  does  it,  eh, 
Bugs? 

One  place  I  always  stop  and  smile,  and 
that's  the  heading  "How-to-Make-It  De- 
partment." I  guess  my  department  is  the 
"How-Aro?-to-Make-It.''  Usually  every- 
thing I  started  went  wrong  the  first  time ; 
but  the  finding  out  why  it  wouldn't  work, 
and  making  it  over  till  it  would,  wasn't  the 
worst  fun  in  the  world.  In  fact,  I  think 
it  was  the  best.    No  fun  simply  copying. 

When  it  came  to  the  electric  clock, 
though,  that  nearly  beat  me.  There's  a 
thing  that  looks  easy,  and  isn't ;  yet  it's 
simple  enough  once  you're  wised  up. 

I  was  sort  of  forced  into  the  clock  craze. 
You  see,  our  kitchen  clock  was  on  the 
blink.  Father  didn't  blame  it — good  old 
clock,  he  said,  it  had  served  him  faithfully 
twenty-five  years,  and  was  worn  out.  Worn 
out  nothing!     I'll  bet  old  Jerome  turned 


The  Clock  Craze 

By  Thomas  Reed 

over  in  his  grave  at  that  libel,  for  one  of 
his  excellent  brass  clocks  ought  to  go  for 
100  years,  and  only  be  talking  baby-talk 
then.  1  knew  what  ailed  it  all  right ;  it  was 
so  full  of  my  contact-springs,  wires,  mag- 
nets and  other  junk,  that  its  regular  works 
had  become  discouraged.  But  that  was  a 
secret  between  me  and  the  clock,  and  there 
were  good  reasons  why  the  secret  was  safe 
with  me. 

Anyhow,  when  the  clock  took  to  stop- 
ping, something  had  to  be  done,  and  done 
quick,  because  mother  would  figure  wrong 
with  her  Saturday  baking,  and  Mrs.  Skil- 
lings  would  get  her  hot  pies  out  on  the 
window-sill  first,  which  was  an  awful 
catastrophe  to  mother,  and  made  her  feel 
as  peevish  as  the  Standard  Oil  does  when  a 
competitor  sells  a  quart  or  so  of  gasoline 
right  under  its  nose. 

I  had  pondered  a  little  on  electric  clocks, 
and  as  I  say  they  looked  easy,  so  I  made 
the  family  a  proposition :  for  half  the 
price  of  a  new  clock  I  would  turn  the  old 
one  into  •  an  electric  clock  that  would  go 
all  the  time  without  winding.  Father  liked 
the  idea  because  his  back  got  twisted  climb- 
ing up  on  a  chair  to  wind  the  thing,  and 
any  clock  at  all  looked  good  to  mother 
provided  it  was  a  going  institution.  I  said 
this  one  you  couldn't  stop  if  you  wanted 
to ;  and  it  would  be  so  accurate  that  Mrs. 
Skillings  would  be  running  over  to  ask 
humbly  what  the  really  correct  time  was. 
This  is  known  as  promoters'  language,  and 
is  powerful.    It  clinched  the  deal.  Father 


Magnet 


^Armature 


Attempt  No.  2,  in  Electric  Clock  Design. 
This  Arrangement  "Worked  Too  Well."  But 
the  Magnet's  Successive  Pulls  on  the  Pendu- 
lum Accumulated  till  it  Banged  Against  the 
Magnet  Like  Jess  Willard  Administering  a 
K.  O. 


handed  over  the  kale  with  a  feeling  which 
if  magnified  a  few  diameters  would  have 
been  enthusiasm. 

Everybody  (including  myself)  expected 
it  would  be  not  over  two  weeks  at  the  out- 
side before  I  had  the  clock  rigged  up  and 


Finally  the  Electric  Clock  Problem  Settled 
Down  to  a   Resurrection  of   Hipp's  Famous 
Pendulum.    But  Oh!  that  "Agate"  Post  !X? 
Likewise  Zowie. 


was  after  Mrs.  SkilMngs*  goat  with  it.  I 
took  the  old  clock  to  pieces  for  the  last 
time,  pulled  out  a  few  superfluous  wheels 
and  springs,  and  inserted  a  pawl  and  rat- 
chet-wheel where  they  would  do  the  most 
good.  Then  I  started  gaily  on  the  electric 
pendulum  that  was  to  drive  it.  I  wished 
afterward  I'd  made  the  pendulum  first. 

It  was  a  grand  pendulum  I  made — a  sec- 
onds-pendulum of  the  due  length  of  39.1 
inches,  with  wooden  rod  and  a  fine  heavy 
bob.  I  was  so  cocksure  that  I  polished  up 
all  parts  as  I  went  along.  But  when  it 
was  done,  it  wouldn't  work. 

There  were  two  or  three  main  reasons 
why.  To  begin  with,  it  was  hung  on  pivots, 
like  a  telegraph  key ;  and  the  heavy  bob 
set  up  so  much  friction  there  that  it  would 
have  taken  about  a  kilowatt  to  drive  it. 
Of  course  it  should  have  been  hung  on  a 
suspension  spring,  which  lets  the  pendu- 
lum oscillate  while  supporting  its  weight 
without  friction.  Bonehead  play  number 
one. 

Well,  I  discarded  my  pivots — tho  I 
hated  to,  they  looked  so  pretty — and  with 
my  pendulum  swinging  easily  from  a 
spring,  I  looked  to  see  her  go.  But  nix. 
Good  strong  magnet,  clean  contacts,  and 


June,  1917 


THE   ELECTRICAL  EXPERIMENTER 


115 


all  that,  but  nothing  doing.  Could  any- 
thing be  wrong  with  my  arrangement? 
Answer,  oui,  oui. 

You  see  I  had  it  rigged  as  in  Fig.  1, 
following  the  idea  of  the  electric  bell. 
When  the  pendulum  swung  over  far  enough 
to  make  contact,  the  magnet  gave  a  vigor- 
ous pull;  but  unfortunately  it  checked  the 


guine  promoter.  My  stockholders,  ignor- 
ant of  the  exactions  of  science,  were  clam- 
oring for  quick  returns  on  their  investment. 
Stockholders  in  this  mood  fall  naturally 
into  sarcasm.  They  say,  "Oh,  you  were 
just  as  sure  as  anything  when  you  were 
after  our  money,  and  now  you  admit  you 
didn't  know  what  you  were  doing.  Of 
course  you're  right  on 


Pendu/um 
rod 


P/af/nc/m  confacr     Tfp/n  6er/r?0/7 


ross  trigger 


Pocod  stee/  6  rod 
t>enf  svff/?/  aog/e 
nofcfied  of /o/? 


Conoecf/og  w/res 
to  bar  d  /nogrtef 


fig  4 


<2L 


Finally   I    Contrived   a   Substitute  for  that  "Agate"    Post  on  the 
Clock  Pendulum,  Relates  the  Author,  and  Decided  that  the  Thing 
to  do  Was  to  "Substitute."    Steel  Proved  Excellent — but  I  Guess 
a  Piece  of  Cheese  Would  Have  Sufficed. 

pendulum  just  as  much  as  it  pulled  it,  and 
the  result  was  nil.  The  slow,  free-swing- 
ing pendulum  acted  differently  from  the 
rapid,  springy  bell-hammer. 

The  two  weeks  were  already  up,  and 
mother  was  beginning  to  peeve,  because 
meanwhile  Mrs.  Skillings  had  put  it  over 
her  again  on  the  pies ;  so  I  hid  my  chagrin 
under  what  I  hoped  looked  like  a  confident 
smile  and  attacked  the  problem  anew. 

The  next  attempt  is  shown  in  Fig.  2.  I 
made  a  flapping  contact,  metal  on  one  side 
and  insulating  mica  on  the  other.  This 
arrangement  worked  too  well,  if  you  get 
me.  The  magnet  gave  a  nice  pull,  and  on 
the  back-stroke  it  let  go,  all  as  per  inten- 
tion. But  now  the  pulls  accumulated  till 
the  pendulum  ended  by  banging  against  the 
magnet  like  Jess  Willard  administering  a 
K-O.  This  pendulum  thing  began  to  seem 
decidedly  not  as  easy  as  it  used. 

Anyhow,  to  have  it  go  at  all  was  some 
consolation.  All  that  was  needed  now  was 
some  arrangement  to  cut  the  current  off 
as  soon  as  the  pendulum  had  all  the  im- 
pulse it  needed,  and  switch  it  on  again 
when  more  was  required.  Now  I  began  to 
appreciate  Hipp's  pendulum,  described  in 
the  text-books.  In  Hipp's  device  (Fig.  3) 
the  electric  contact  is  made  by  means  of 
a  notched  post  attached  to  the  pendulum, 
which  normally  pushes  past  a  little  swing- 
ing trigger  attached  to  the  contact-spring. 
As  the  pendulum  loses  its  amplitude,  there 
comes  a  moment  when  the  notch  in  the 
post  just  catches  the  trigger,  and  then  when 
it  starts  the  other  way  the  trigger  is 
raised  and  the  contact  made,  the  magnet 
is  energized,  and  gives  the  pendulum  a 
push.  The  notch  now  brushes  by  the  trig- 
ger again,  until  the  narrowing  swings  allow 
it  to  catch  once  more,  and  the  process  is 
repeated.  As  the  battery  runs  down,  the 
push  is  weaker  and  the  contact  has  to  be 
made  oftener;  but  the  mechanism  does  this 
automatically  until  the  battery  is  exhausted. 

Hipp's  rinktum  looked  effective,  if  one 
could  only  make  it ;  but  being  a  clock- 
maker,  old  Hipp  had  specified  agate  as  the 
material  for  his  notched  post.  Agate,  he 
says,  just  like  that:  "Take  a  piece  of  agate, 
you  know,  and  put  a  notch  in  it."  Oh, 
yes.  The  only  agate  I  had  ever  heard  of 
was  an  agate  marble ;  and  it  didn't  look 
exactly  like  easy  stuff  to  make  anything  of. 

Four  weeks  had  now  gone  by,  and  the 
family  had  lost  all  their  peevishness ;  that, 
is,  they  had  exchanged  it  for  black  looks 
and  language  not  calculated  to  please.  I 
was  reaping  the  usual  reward  of  the  san- 


the  track  of  it  this 
time  —  pooh,  pooh  ! 
Have  it  all  ready  to- 
morrow morning  at 
breakfast,  I  suppose. 
Well,  a  fool  and  his 

money  "    all  that 

encouraging  stuff.  I 
know    just    how  to 
treat  impatient  inves- 
tors now ;  but  at  that 
time     the  situation, 
coming  on  top  of  my 
defeat  at  the  hands  of 
Nature,  got  my  goat, 
and   I'm  ashamed  to 
say  I  declared  bank- 
ruptcy   and  quit. 
Father  bought  a  new 
kitchen  clock,  and  is- 
sued a  manifesto 
(having  got  an  inkling  of  what  ailed  its 
predecessor)   that  if  I  monkeyed  with  its 
insides  to  the  100th  part  of  a  monk,  he 
would  monkey  with  my  outside ;  and,  in  the 
vigorous  language  of  the  day,  I  was  not 
to  forget  it. 

I  knew  why  a  prophet  is  without  honor 
in  his  own  country.  Believe  me,  my  home 
reputation  as  a  budding  scientific  and  busi- 
ness man  was  badly  damaged ;  to  be  more 
exact,  it  looked  like  the  place  where  a  42 
cm.  shell  has  recently  landed.  But  the 
clock  craze  had  struck  in ;  and  oblivious 
of  everything,  in  cloistered  seclusion  be- 
hind the  barn  I  pondered  upon  Hipp  and 
his  exasperating  agate. 

I  pondered  long  before,  in  a  burst  of 
enlightenment,  the  great  truth  of  Bugdom 
burst  upon  me — use  some  other  material, 
even  if  it  isn't  as  good,  anything  at  all 
for  a  starter.  Couldn't  I  use  steel,  brass 
even  ?  it  would  last  long  enough  to  try  it 
anyhow.  It  makes  me  laugh  now,  my  great 
discovery;  but  do  you  know  that  some- 
times the  getting  rid  of  a  fixt  idea  is  the 
hardest  part  of  an  undertaking?  Why,  I 
could  have  used  pewter,  paper,  I  guess 
even  cheese  if  you  took  it  near  the  rind. 

Don't  let  anyone  discourage  you,  Bugs,  by 
specifying  costly  and  unusual  materials. 
The  inventor's  describing  his  rinktum  the 
way  it  looks  after  he's  got  it  all  babied 
up  in  its  final  Easter  dress;  but  just  for 
a  trial  you  don't  need  the  platinum,  Bake- 
lite,  Empire  cloth,  and  "S.C."  wire — no,  sir, 
you'll  find  all  you  really  require  in  the 
good  old  junk-box  as  usual.  Me,  I  grew 
so  independent  finally  in  the  matter  of  ma- 
terials that  I  hardly  recognized  more  than 
two  kinds — conductors  and  insulators  ! 

So,  having  got  the  agate  out  of  my  head 
— -"solid  agate"  I  guess  my  old  bean  was — 
I  used  steel  for  the  post  and  brass  for  the 
trigger ;  and  as  to  durability,  let  me  tell 
you  that  after  nearly  twenty  years  use  I 
can't  with  the  naked  eye  detect  any  wear. 

Oh,  yes,  I  made  the  clock,  but  I  had  a 
long  hunt  for  something  on  Hipp's  prin- 
ciple in  a  form  which  the  amateur  work- 
shop might  turn  out.  After  many  trials  I 
evolved  the  form  shown  in  Fig.  4 ;  and  I 
make  you  free  of  my  invention,  Bugs,  hop- 
ing someone  will  be  interested  enough  to 
make  himself  an  electric  clock.  There's 
lots  of  enjoyment  in  listening  to  its  sedate 
tick-tock  as  it  breaks  up  infinite  time  into 
the  small  units  we  need  to  make  our  good 
or  bad  use  of.  Maybe,  now  that  the  war 
will  debar  us  from  wireless  work  for  a 
while,  you'll  feel  inclined  to  take  up  this 


fascinating  subject  of  clocks;  and  if  so,  I 
have  many  valuable  "wrinkles"  which  I 
should  be  delighted  to  share  with  you. 
Only,  avoid  my  experience,  and  don't  make 
a  business  proposition  of  it  at  first.  C-U-L, 
O-M.  -.- 


NEW  RESISTANCE  MATERIALS, 

A  New  York  concern  is  now  marketing 
tungsten  and  molybdenum  in  sheet,  rib- 
bon and  plate  form.  This  development 
makes  these  metals  suitable  for  new  uses 
and  opens  to  them  a  much  wider  field 
of  usefulness  than  has  heretofore  existed. 
The  tungsten  and  molybdenum  ribbon  is 
being  made  in  widths  of  about  Y\  in. 
(6.35  mm.)  and  in  lengths  of  several 
yards.  In  this  shape  the  ribbons  ought 
to  be  ideal  material  for  the  manufacture 
of  heaters  of  various  descriptions  and  suit- 
able for  high  temperatures,  the  manu- 
facturer points  out.  The  United  States 
Government  has  already  placed  an  order 
for  plates  of  these  metals  for  spark  gaps 
on  wireless  outfits  to  be  used  on  its  Mos- 
quito Fleet. 


KINKS  FOR  THE  DRAFTSMAN. 

The  first  "kink"  shown  is  a  new  section- 
liner.  There  are  a  great  number  of  appli- 
ances on  the  market  for  this  purpose,  but 
the  one  described  will  do  the  same  work 
as  the  most  expensive  device,  its  advantage 
being  simplicity. 

It  consists  of  a  sheet  of  celluloid  cut  as 
shown.  The  parts  shown  in  black  are  cut 
away  with  a  sharp  knife,  leaving  a  kind  of 
grid.  To  use  this  section-liner  place  its 
base  close  to  the  Tee-square  and  place  the 
pen  or  pencil  into  the  opening  and  draw 
a  section-line,  following  the  outline  of  the 
grid.  Without  moving  either  Tee-square 
or  section-liner,  place  pen  into  the  next  slot 
and  so  on. 

The  two  corners  "X"  and  "Y"  are  cut 
away  to  the  angle  of  threads  used  and  these 
may  come  in  handy  when  drawing  bolts, 
etc. 

The  second  "kink"  will  save  those  drafts- 
men that  are  oft  repetition  work  much  time 
and  trouble.  It  consists  of  the  following: 
Draw  all  those  bolts,  nuts,  washers,  fit- 
tings, etc.,  that  are  used  over  and  over 
again  in  numerous  sizes  on  a  sheet  of 
tracing  cloth  and  ink  it  in.  Be  sure  to 
mark,  in  the  case  of  nuts  and  bolt-heads, 
from  where  you  strike  the  radii;  see  point 
"M";  point  "N"  shows  the  height  of  the 
bolt  head  arc. 

As  most  offices  use  transparent  drawing 


A    Celluloid    Section     Liner    for  Draftsmen 
and  a  Scheme  for  Quickly  Drawing  Nuts  or 
Bolt- Heads  of  Any  Size. 

cloth,  the  standard  sheet  can  easily  be  slipt 
under  the  paper  and  the  outlines  traced 
thru.  In  the  case  of  many  hundred  bolts, 
etc.,  required,  say  in  details  of  bolts  for 
pipe  lines,  etc.,  the  saving  of  time  will  be 
several  hours  and  a  much  neater  drawing 
will  be  the  result. 

Contributed  by         C.  A.  OLDROYD. 


ii6 


THE  ELECTRICAL  EXPERIMENTER 


June,  1917 


The  Influence  of  Light  upon  the  Contact  Potential  of 

Selenium  and  of  Cuprous  Oxid 


THE  change  in  resistance  of  crystal- 
line selenium  and  other  light  sensitive 
substances,  such  as  stibnite,  cuprous 
oxid,  etc.,  under  the  action  of  light  and  oth- 
er agencies,  has  been  explained  on  the  as- 
sumption that  it  is  due  to  a  liberation  of 
conducting  electrons  from  the  atoms  of  the 
material  in  question.*  In  other  words,  the 
change  may  be  considered  as  due  to  a 
change  in  the  atom  itself.  If  this  expla- 
nation is  correct,  then  other  properties  of 
these  substances,  which  also  depend  upon 
inter-atomic  forces,  should  show  a  varia- 
tion from  light  to  dark.  The  authors  in- 
vestigated the  influence  of  illumination  up- 
on the  contact  potential  of  selenium  and 
of  cuprous  oxid,  since  this  property  is  one 
of  those  mentioned  above. 

Using,  as  a  check  upon  each  other,  two 
different  methods,  Figs.  1  and  2  of  deter- 
mining contact  potentials,  it  was  found  that 
a  change  did  take  place  in  both  substances 
upon  illumination.  In  the  case  of  selenium, 
this  difference  amounted  to  something  over 
— 0.1  volt,  several  specimens  being  exam- 
ined. The  value,  in  the  dark,  of  the  con- 
tact potential,  relative  to  clean  copper,  was 
about  — 0.4  volt,  in  the  light  about  — 0.5  volt, 
i.e.,  the  selenium  surface  becomes  more 
negative  on  being  illuminated.  With  cup- 
rous oxid,  of  which  but  one  specimen  has 
been  examined  thus  far,  the  effect  is  not 
so  great,  being  about  — 0.025  volt. 

In  the  case  of  selenium  the  effect  is  very 
marked,  even  when  light  of  very  low  in- 
tensity was  used,  as  can  be  seen  from  the 
curve  in  Fig.  3,  which  shows  the  relation 
between  the  change  in  contact  potential  and 
lamp  voltage.  Thus,  with  a  lamp  voltage 
of  25  volts  (normal  110)  the  change 
amounts  to  about  0.035  volts,  yet  at  110 
volts  at  which  the  intensity  of  illumination 
has  increased  by  a  factor  ©f  about  2,000 
over  that  at  25  volts,  the  effect  is  only  3}4 
times  as  great. 

Until  recently  the  most  widely  accepted 
theory  of  the  change  in  resistance  of  sele- 
nium with  a  variation  of  the  intensity  of 
illumination  has  been  that  proposed  by  Pro- 
fessor A.  H.  Pfund,  of  Johns  Hopkins  Uni- 
versity. According  to  this  theory,  the  ef- 
fect of  light  is  in  the  nature  of  an  internal 
photo-electric  effect,  i.e.,  the  atoms  of  sele- 
nium expel  electrons,  the  velocity  of  which 
is  too  low  to  allow  their  escape  from  the 


By.  E.  H.  KENNARD  and  E.  O.  DIETERICH 
Department  of  Physics  (University  of  Minnesota) 

nated,  the  concentration  of  free  electrons 
would  be  increased,  and  one  should  expect 
diffusion  of  these  electrons  into  the  darker 
portions,  leaving  the  part  illuminated  more 
positively  charged.  The  negative  sign  of 
the  change  in  contact  potential,  however,  at 
once  rules  out  the  diffusion  hypothesis  and 
makes  the  simple  theory  mentioned  above 
inadequate.  An  hypothesis  which  better 
fits  the  facts  is  that  contained  in  a  theory 
recently  proposed  by  Professor  F.  C.  Brown 
of  the  Iowa  State  University,  which  as- 
sumes that  the  action  of  light  consists  in 
changing  the  rate  of  recombination  of  con- 
ducting electrons  with  the  selenium  atoms, 
or,  in  other  words,  it  decreases  the  potential 
energy  of  the  electrons  in  the  inter-mole- 
cular spaces. 

POPULAR  DISCUSSION  ON  THE 
PRODUCTION  OF  HELIUM 
By  Mark  Fushman. 

In  a  spectroscopic  investigation,  Janssen 
and  Norman  Lockyer  observed  in  the  at- 
mospheres of  the  sun  and  many  fixt  stars, 
a  bright  yellow  line  which  could  not  be 
associated  with  that  of  any  known  sub- 
stance. To  this  new  substance  they  gave 
the  name  "Helium."  Helium  was  discov- 
ered on  the  earth  in  1895  by  Ramsay  and 


SO  7S 

Lamp  l/o/foqe 


Curve  Showing   Relation   Between  Light  on 
Selenium  and  the  Contact  Potential. 

interior,  hence  they  produce  increased  con- 
ductivity. The  true  explanation,  however, 
does  not  seem  to  be  as  simple  as  this,  for 
on  the  above  theory,  in  the  regions  illumi- 

*  A  more  complete  discussion  of  this  wort  is 
to  be  found  in  the  Physical  Review  for  January, 
1917.  This  article  prepared  for  The  Electrical 
Experimenter.'" 


< 

AAA/ 

)  Se. 

c 

Fig-  2  @ 

Ionization  Method  of  Measuring  Contact  Po- 
tential. This  Method  Is  Also  a  Null  Method 
as  the  Diagram  Indicates.  S  Is  a  Copper 
Strip  Coated  with  Polonium,  the  a-Particles 
from  Which  Ionize  the  Air  Above  the  Sele- 
nium, Se,  But  Do  Not  Strike  the  Selenium 
Surface.  G,  as  in  the  Other  Method,  Is  a 
Brass  Gauze  Connected  to  the  Electrometer. 

Travers,  who  obtained  it  by  heating  the 
rare  mineral  Cleveite.  Later  on,  it  was 
found  that  this  element  is  a  companion  to 
Argon.  Lastly,  it  was  also  discovered  in 
the  atmosphere. 

Helium  has  an  atomic  weight  of  4.00  and 
is  monatomic,  i.e.,  that  is — the  helium  mole- 
cule consists  of  only  one  atom.  At  or- 
dinary temperatures,  helium  is  a  colorless 
gas;  it  boils  at  about  269°C,  and  by  evap- 
oration at  a  pressure  of  0.15  mm.,  a  tem- 
perature 1.5  above  absolute  zero  was  ob- 
tained. 

The  fact  that  this  new  gaseous  element 
occurred  in  certain  minerals  was  consid- 
ered very  remarkable.  A  new  light  was 
thrown  on  this  subject  by  the  discovery  of 
radioactivity.  Radioactive  substances  are 
known  to  emit  spontaneously  electrons,  or 
particles,  as  they  are  now  termed.  As 
these  particles  are  emited  the  substance 
changes  into  a  new  and  different  element ; 
this  is  known  as  the  disintegration  theory 
of  radioactivity.  In  looking  for  a  disin- 
tegration product,  the  presence  of  helium 
is  noteworthy,  for  helium  is  found  in  min- 
erals containing  uranium  or  thorium. 
Rutherford  and  Soddy  suggested  that  hel- 
ium might  be  a  product  of  disintegration. 
Ramsay  and  Soddy  obtained  thirty  mini- 
grams  of  radium  bromid  and  dissolved  it 
in  water.  Radium  bromid  produces  hydro- 
gen and  oxygen,  so  these  gases  were 
drawn  off  and  there  remained  a  small 
bubble  of  residue  gas,  which  was  intro- 


ducd  into  a  vacuum  tube  and  showed  the 
characteristic  lines  of  helium.  When  a 
very  old  sample  of  radium  bromid  was 


Condenser  Method  for  Measuring  Quick 
Changes  in  the  Contact  Potential.  The  Elec- 
trometer, E,  Can  Be  Connected  by  Means  of 
Suitable  Clips,  Either  to  the  Gauze,  G,  the 
Selenium  Plate,  Se,  or  the  Copper  Plate,  C. 
As  Shown  in  the  Diagram  the  Connections 
Are  Such  That,  by  Means  of  the  Poten- 
tiometer, P,  the  Deflection  of  the  Electrom- 
eter Which  Occurs  When  Light  Falls  on  the 
Selenium  Plate  Thru  the  Gauze,  Can  Be 
Made  Zero,  and  the  Change  in  Contact  Po- 
tential Determined.  Proper  Precautions  Are 
Taken,  of  Course,  to  Secure  Proper  Electro- 
static Screening. 

used,  the  residue  bubble  gave  the  complete 
spectra  of  helium.  This  experiment 
showed  that  helium  was  produced  by  rad- 
ium. Helium  is  also  produced  from  active 
forms  of  actinium.  This  shows  also  that 
helium  ought  to  be  a  common  product  of 
both  substances. 

Radium,  owing  to  its  property  of  giv- 
ing forth  particles,  gives  forth  certain  par- 
ticles which  are  called  alpha  particles.  In 
old  radioactive  material  there  is  a  large 
collection  of  helium  which  goes  to  prove 
that  the  alpha  particle  is  connected  with 
helium  or  rather  that  an  alpha  particle  is 
a  helium  atom.  An  estimate  of  the  rate  of 
production  of  helium  from  radium  has 
been  made  by  Ramsay  and  Soddy.  1  gram 
of  radium  produces  daily  0.499  cu.  mm. 
helium  gas. 

Investigation  seems  to  show  that  the 
alpha  particles  from  actinium  and  thorium 
are  also  atoms  of  helium;  therefore  we 
may  regard  these  elements  as  compounds 
of  helium  and  some  unknown  element.  It 
appears  that  helium  plays  an  important 
role  in  the  formation  of  the  radioactive 
elements.  It  may  be  that  helium,  like  hy- 
drogen, plays  a  part  as  one  of  the  elemen- 
tary elements  of  which  the  heavier  atoms 
are  built. 

It  is  supposed  that  at  the  center  or 
rather  in  the  depths  of  the  earth,  where 
the  pressure  is  great  and  the  temperature 
high,  radioactive  elements  are  being  formed 
and  the  deposits  of  radio-elements  now  on 
the  earth's  surface  were  thrown  up  from 
below  ages  ago. 

CARD  INDEXING  THE  "E.E." 

I  have  a  little  stunt  which  I  thought 
might  be  of  interest  to  other  readers,  as 
follows : 

I  took  a  small  card  index  that  is  sold 
for  a  recipe  file  and  sold  for  $1.00  any- 
where, and  as  I  read  my  Electrical  Ex- 
perimenter each  month,  I  note  on  the 
cards  all  those  things  that  may  be  of  fu- 
ture use  to  me,  in  this  way: 

Antenna  Switch-Exp.  Jan.,  1917,  page 
658:  then  at  any  time  that  I  want  to  make 
anything,  I  look  at  the  cards  and  all  ar- 
ticles in  my  stack  of  magazines  are  listed 
there,  which  saves  hunting  thru  a  stack  of 
several  dozen  magazines  for  something  you 
have  seen,  hut  cannot  find. 

Contributed  by  F.  C.  BROWN. 


June,  1917 


THE   ELECTRICAL  EXPERIMENTER 


High  Frequency  Apparatus  and  Experiments 


By  HUBERT  A.  McILVAINE 


MANY  experimenters  either  do  not 
realize  the  vastness  of  the  high 
frequency  Held,  or  think  that  they 
have  not  money  enough  to  buy 
the  necessary  apparatus.  It  is  the 
purpose  of  this  article  to  explain  the  man- 
ner of  constructing  a  few  simple  instru- 
ments, and  the  method  of  carrying  out 
some  simple  experiments. 

In  the  first  place,  a  high  frequency  trans- 
former must  be  constructed.  An  Oudin 
coil  will  be  the  best  for  all-around  work, 
and  it  may  be  made  in  the  following  simple 
manner :  Procure  an  ordinary  pasteboard 
mailing  tube,  about  2l/2  inches  in  diameter 
and  10  inches  long,  and  cover  it  with  a  thin 
coat  of  white  shellac.  While  this  is  still 
wet,  wind  the  tube  with  fine  copper  wire, 
spacing  the  turns  far  enough  apart  to  en- 
sure proper  insulation.  (Enough  wire  may 
be  found  in  an  old  telephone  ringing  mag- 
net.) Glue  this  tube  upright  to  a  base  and 
fasten  three  posts  on  the  base.  The  pri- 
mary coil  may  be  made  of  6  turns  of  No.  14 
copper  wire,  connected  as  in  the  diagram, 
Fig.  1. 

A  condenser  can  be  made  by  coating  both 
sides  of  old  photographic  plates  with  tin- 
foil, and  placing  them  in  a  cigar  box,  to 
hold  them  in  an  upright  position.  A  spark 
gap  of  most  any  type  will  answer.  A  V/i 
inch  spark  coil  should  be  used. 

When  the  above  instruments  are  con- 
structed, they  should  be  connected  up  as 
shown  in  diagram,  and  the  apparatus  is 
ready.  When  the  spark  coil  is  operated,  a 
brush  discharge  of  purple  light  should  ap- 
pear around  the  free  end  of  the  secondary, 
ucoer  end  of  coil,  with  sparks  about  2  or  3 
inches  in  length.  If  a  piece  of  metal  is 
held  in  the  hand,  a  very  long  spark  can  be 
drawn  from  the  secondary  wire,  without 
the  slightest  shock.  If,  however,  the  spark 
is  drawn  directly  into  the  hand,  a  severe 
sting  may  result.  On  the  other  hand,  if  a 
pane  of  glass  is  held  between  the  secondary 
wire  and  the  hand,  a  spark  may  be  received 
directly  into  the  hand  without  pain ;  the 
spark,  being  dispersed  or  spread  out  while 
passing  over  the  glass. 

If  a  person  insulated  from,  the  ground 
grasps  the  free  terminal  of  the  secondary,  a 
match  may  be  lighted  from  any  part  of  the 
body.  A  Geissler  tube  will  light  up  bright- 
ly, when  brought  near  the  body.  This  is 
also  a  good  way  in  which  to  treat  heart  and 
nervous  diseases.  If  there  is  any  local 
trouble,  a  grounded  metallic  object  should 
be  brought  near  the  point  to  be  treated,  thus 
taking  out  the  induced  current  at  this 
point. 

An  interesting  experiment  is  to  produce 
an  artificial  Aurora  Borealis.  This  may  be 
accomplished  with  a  large  electric  bulb  (a 
100  watt,  burned  out  one  will  do),  covering 
the  tip  with  tin-foil.     Insulate  the  bulb 


Fig.  1,  Proper  Connections  for  Small 
"Oudin"  High  Frequency  Coil  Excited  by  a 
Spark   Coil   or   Step-up   A.  C.  Transformer. 

from  the  ground  and  fasten  the  screw  end 
to  the  secondary  wire.  Place  a  strong  per- 
manent magnet  on  each  side  and  start  the 
coil.    A  beautiful  auroral  effect  will  form 


Wood  dowe//  p/n 


G/oss  feet 


Fig.  2.    Manner  of  Constructing  Small  "Oudin"  Type  High  Frequency  Coil  for  Carrying  on 
a  Series  of  Interesting   Experiments.     One  of  These   Is  the  Artificial   "Aurora  Borealis," 
Which  Is  Produced  with  the  Aid  of  an  Incandescent  Lamp  Bulb,  Having  Its  Tip  Portion 
Coated   with   Tinfoil,   and   Connected   as  Shown. 


inside  the  bulb.  Also,  if  there  are  any 
loose  pieces  of  filament,  these  will  begin  to 
revolve  rapidly  about  the  inside  of  the  bulb 
and  will  continue  to  do.  so  for  some  time 
after  the  current  is  shut  off,  and  each  time 
they  touch  the  glass  a  shower  of  sparks  will 
fly  in  all  directions. 

A  by-product  of  high  tension  electrical 
stress  in  the  air  is  ozone.  Ozone  is  merely 
electrified  oxygen.  When  a  high  voltage 
discharge  takes  place  in  air  or  pure  oxygen 
gas,  the  atoms  of  oxygen  are  "torn  apart" 
and  exist  in  what  is  known  as  a  nascent 
state.  In  this  state  each  atom  combines 
with  one  other  atom,  and  the  chemical  af- 
finity of  these  two  atoms  is  such  that,  as 
there  is  nothing  with  which  they  can  com- 
bine, these  atoms  pull  to  themselves  and 
combine  with  a  third  atom  of  oxygen. 
Thus  it  is  that  a  new  gas>  is  formed.  This 
gas  is  much  denser  than  oxygen  and  is 
many  times  as  active.  The  smell  of  ozone 
is  very  strong  and  there  seems  to  be  a  slight 
difference  in  the  smell  of  ozone  produced 
with  a  static  machine  and  the  ozone  pro- 
duced with  high  frequency  current.  Ozone 
is  an  excellent  "germ  killer,"  as  it  kills  all 
kinds  of  disease  germs  on  contact.  If  it  is 
administered  properly,  and  in  time,  it  will 
cure  consumption. 

The  electric  stress  about  the  coil  is  so 
great,  that  immense  quantities  of  ozone  are 
constantly  being  generated.    In  order  to 


treat  diseases  obtain  a  box  which  is  large 
enough  to  contain  the  coil  and  still  leave 
enough  space  (about  4  inches)  on  each  side 
to  prevent  the  coil  from  "grounding."  Run 
the  coil  wires  through  the  box  and  leave  the 
free  end  of  the  secondary  about  six  inches 
long,  so  as  to  obtain  good  radiation  sur- 
face. Place  a  hose  in  the  top  of  the  box 
and  another  in  the  lower  part  of  one  side. 
Paraffin  the  box  to  prevent  leakage,  and 
put  a  small  window  in  one  side  so  that  the 
coil  action  may  be  viewed.  Either  air  or 
pure  oxygen  is  taken  in  thru  the  lower 
hose  and  the  ozone  is  inhaled,  or  otherwise 
applied  from  the  upper  hose.  In  fumiga- 
tion, treatment  of  coughs,  pneumonia,  colds, 
and  for  many  other  medical  uses,  besides 
oxidation  of  certain  materials,  bleaching 
flour  and  cloth,  experimenting  with  its  use 
in  welding  and  many  other  commercial  uses, 
ozone  is  a  most  valuable  agent. 

Taking  the  high  frequency  field  as  a 
whole,  it  is  well  worth  while  for  more  ex- 
perimenters to  work  with  it.  High  fre- 
quency current  has  the  properties  of  both 
static  and  galvanic  electricity,  besides  many 
properties  which  neither  of  the  above  pos- 
sess. It  will  pass  over  ordinary  insulators, 
such  as  glass,  almost  as  easily  as  low  fre- 
quency current  will  pass  thru  copper.  It 
travels  over  the  surface  of  a  conductor 
and  seldom  thru  it.  Its  oscillations  are 
(Continued  on  page  154) 


1  18 


THE  ELECTRICAL  EXPERIMENTER 


June,  1917 


The  Problem  of  Using  The  Energy  in  Sunlight 


INFRACTION 
CRATING 
PLANE 


A  RESEARCH  PROBLEM  AND 
OUTLINED  SOLUTION. 

SUPPOSE  all  the  electrical  energy 
used  in  the  world  for  power,  heat 
and  light  to  be  obtained  for  nothing. 
How  the  world  would  be  changed. 
Energy  in  electrical  form,  of  limitless 
amount  and  absolutely  free,  is  falling  over 
a  world  provided  with  apparatus  and  appli- 
ances for  the  use  of  electric  energy.  But 
the  world  does  not  use  this  constant,  ex- 
haust.less  flood  of  free  energy;  it  digs  coal 
out  of  the  earth  and  depends  on  that  for  its 
power,  heat  and  light. 

The  greatest  discovery  any  experimenter 
can  seek  is  the  direct  utilization  of  solar 
energy  as  the  source  of  power  for  the 
world's  work. 

The  following  out- 
line of  experimental 
research  may  enable 
some  so  circum- 
stanced that  they 
can  make  the  inves- 
tigations, to  make 
this  discovery.  In 
this  work  I  seek  to 
obtain  energy  from 
solar  radiation  by 
causing  it  to  pro- 
duce ordered  accel- 
eration of  electrons 
about,  and  in,  a  con- 
ductor  —  electric 
current. 

Problem:  —  To  Ob- 
tain Electrical 
Energy  "Directly" 
from  Solar  Radi- 
ation. 

1°.  The  solution 
here  proposed  is 
based  on  the  follow- 
ing principles :  1. 
The  solar  radiation 
is  electro  -  magnetic. 
2.  The  flow  of  en- 
ergy is  in  the  direc- 
tion of  propagation, 
sun  to  earth.  3.  The 
periodic  action,  vi- 
bration, is  at  right 
angles  to  the  propagation,  and  is  cyclic 
variation  of  two  vector  magnitudes,  elec- 
tric force  and  magnetic  force.  4.  Solar 
radiation  produces  acceleration  in  electrons 
in  its  path  that  have  a  component  of  motion 
in  a  certain  relation  to  it.  5.  Acceleration 
of  an  electron  produces  an  (opposite)  ac- 
celeration of  surrounding  electrons. 

2°.  The  experimental  solution  is  rendered 
difficult  by  the  great  complexity  of  the  so- 
lar radiation.  Take  a  small  area  in  a  plane 
at  right  angles  to  the  solar  beam.  At  every 
instant  there  are  passing  Jhru  this  waves  of 
millions  of  different  lengths  and  periods, 
and  at  every  instant  they  are  in  millions  of 
different  phases,  and  the  electric  and  mag- 
netic vectors  in  these  waves  at  any  instant 
are  in  millions  of  different  directions  and 
continually  changing  at  every  point. 

3°.  A  beam  of  one  wave  length  or  period 
approximately  may  be  obtained  by  the  use 
of  a  prism  or  a  grating,  preferably  a  grat- 
ing. 

4°.  A  beam  with  the  electric  vector  con- 
fined to  one  direction  may  be  obtained  by 
the  use  of  a  polarizing  mirror  or  a  pile  of 
plates ;  or  to  two  directions,  giving  elliptic 
resultant  by  an  additional  mirror  or  a 
rhomb. 

5°.  A  complex  beam,  a  beam  of  one 
wave  length,  or  a  beam  of  one  wave  length 
and  one  direction  of  electric  vector,  may  be 
concentrated  to  a  small  area,  circular  or 
linear,  in  which,  at  any  given  instant,  there 


By  Prof.  I.  Thornton  Osmond 

is  but  one  phase  in  the  focus  of  a  lens, 
spherical  or  cylindrical,  all  waves  (of  a 
given  length)  are  in  the  same  phase  at  any 
instant. 

6°.  Two  parts  of  a  complex  beam,  of  a 
one  wave  length  beam,  or  of  a  one  wave 
length  and  one  electric  vector  beam  may  be 
made  to  traverse  the  same  space  by  the  use 
of  a  biprism  or  a  mirror  in  such  a  way  that 
the  intensity  at  various  places  at  any  in- 
stant has  values  that  vary  from  zero  to 
four  times  that  of  the  single  beam. 

7°.  Take  a  vessel  with  walls  readily  tra- 
versed by  the  solar  radiation  and  that  may 
be  exhausted  to  high  vacuum  if  desired, 
and  produce  in  it  an  abundant  supply  of 
electrons  (as  by  a  filament  or  wire  heated 
by  a  current )  and  bring  into  this  vessel 
electrodes  to   receive  the   radiant  energy 


EVACUATED  TUBE 


Arrangement  of  Apparatus  as  Suggested  by  Mr.  S.  Cohen,  for  Use  in  Determining 
the  Most  Effective  Energy  Components  in  "Sunlight."  The  Various  Rays  Are 
Focussed  from  a  Diffraction  Grating  Into  a  Vacuum  Bulb,  and  Their  Magnitude 
Measured  by  the  Reaction  Deflection  of  an  Electro-static  Galvanometer  Connected 
Across  Two   Electrodes,   Charged   As  Shown   by  a   High   Tension   Arc  or  Other 

Generator. 


treated  as  in  3,  4,  5,  6,  and  send  it  thru  an 
external  circuit,  containing  such  capacity, 
induction,  and  resistance  as  may  be  re- 
quired, and  some  form  of  indicator,  as  a 
galvanometer,  telephone,  or  wave  detector. 
(The  vessel,  vacuum  and  ionizer  may  not 
be  necessary;  possibly  the  energy  of  the 
treated  beams  can  be  taken  by  the  elec- 
trodes without  these.) 

8°.  By  the  various  combinations  of  ap- 
paratus, in  10-below,  using  solar  radiation, 
produce  in  the  vessel  the  linear  focus,  or 
foci,  of  the  different  character  beams  of  3 
and  4  above;  or  produce  within  it  the  space 
variations  of  intensity  of  6  above,  with  any 
of  the  kinds  of  beams  named.  Try  various 
relations  of  variously  formed  electrodes 
to  the  focus,  or  foci,  and  to  the  regions  of 
different  intensity;  with  various  ionizing 
current,  as  direct,  high  frequency  alter- 
nating, or  spark  discharges  of  coil  or  con- 
denser, and  various  inductances,  resistances 
and  capacities  in  the  external,  or  receiv- 
ing, circuit — using  one  or  another  of  the 
indicators  named  above. 

9°.  Apparatus  for  Proposed  Experimen- 
tal Solution. — 1.  Lens  of  sulfur,  paraffin  or 
synthetic  resin,  cylindrical,  27  cm.,  chord, 
40  cm.  long,  50  cm.  focal  length ;  two  oth- 
ers, each  22  cm.  chord,  40  cm.  long,  50  cm. 
focal  length.  2.  Grating,  plane,  34  ele- 
ments, a+b=1.2  cm.,  40x41  cm.  inside  of 
frame.  Also  a  curved,  cylindrical  grating, 
100  cm.  radius,  32  elements,  a4-b=1.5  cm.  3. 


Fresncl  Mirrors,  one  40x40  cm.,  the  other 
40x60  cm. ;  the  latter  serving  for  a  Lloyd 
single  mirror,  if  wanted.  4.  Biprism,  sul- 
fur, 25  cm.  wide,  40  cm.  long;  small  an- 
gles 7°,  large  angle  166°.  5.  Polarizers,  re- 
flecting metal  plate,  pile  of  plates,  glass  or 
sulfur;  fine  grating;  Fresnel  rhomb.  6. 
The  transferring,  or  receiving,  apparatus 
described  in  7  above  (which  may  not  be 
necessary).  7.  Accessory  apparatus,  as  ca- 
pacity, resistance,  inductance,  and  indicat- 
ing instruments. 

Wherever  wave  length  enters  into  the 
design  of  these  pieces  of  apparatus  it  is 
taken  as  from  0.6cm.,  to  1.2cm.,  as  being 
near  the  lower  limit  of  waves  well  above 
the  longest  heat  waves,  i.e.,  waves  produc- 
ing molecular  motion.  Greater  wave 
lengths,  with  corresponding  changes  in  de- 
sign may  be  found 
to  give  better  results. 

10°.  Apparatus 
Combined  for  Ex- 
periments, giving 
various  kinds  of 
radiation  beams. — 1. 
Grating  and  Lens,  or 
Lenses ;  or  Lens  and 
Curved  Grating.  2. 
Grating  and  Polar- 
izer. 3.  Grating, 
Polarizer  and  Lens, 
or  Lenses.  4.  Grat- 
ing, Polarizer  and 
Ellipsizer.  5.  Grat- 
ing, Polarizer,  Ellip- 
sizer and  Lens.  6. 
Lens  and  Biprism  or 
Lens  and  Mirror.  7. 
Grating,  Lens  and 
Biprism  and  Mirror. 
8.  Grating,  Polar- 
izer, Lens  and  Bi- 
prism. 

For  this  work  it 
would  be  desirable, 
perhaps  necessary, 
to  have  a  complete- 
ly metal  (iron)  in- 
closed container  of 
the  instruments.  If 
a  room  of  this  kind 
is  not  available,  an 
iron  case  2.4  meter  (m.)  long  0.5m.  wide, 
0.8m.  high  will  contain  any  of  the  com- 
binations of  apparatus  given  above  and  the 
transferring,  or  receiving,  apparatus.  The 
mounting  of  the  combination  of  apparatus 
should  permit  following  the  sun  or  direct- 
ing to  any  point  within  90°  of  it. 

An  electrolytic  process  of  deoxidation 
has  been  patented  in  the  United  States  by 
Pascal  Marino  of  London.  The  object  to 
be  treated  is  made  the  cathode  in  an  elec- 
trolyte containing  phosphoric  acid.  In  ad- 
dition to  its  normal  function  of  carrying 
the  current,  this  acid  acts  as  a  solvent  upon 
rust  without  attacking  the  steel  or  iron 
body  beneath.  It  is  in  this  last  detail  that 
its  chief  availability  lies,  since  nitric,  sul- 
furic or  hydrochloric  acids  would  not  dis- 
play such  moderation.  Finally,  the  phos- 
phoric acid  is  beneficial  in  preventing  sub- 
sequent further  rusting. 

The  electrolyte  is  made  by  adding  ten 
parts  of  phosphoric  acid  to  ninety  parts  of 
water,  or  by  adding  10%  o  the  acid  to  a 
10%  solution  of  sodium  phosfate. 

Due  to  the  advent  of  the  war,  we  are 
particularly  desirous  of  obtaining  manu- 
scripts describing  original  and  practical 
"Electrical  Experiments."  We  shall 
continue  to  publish  Radio  articles,  but 
what  we  need  is  snappy  "Electrical" 
articles.  Be  on  guard  for  the  enemy — 
Repetition! 


June,  1917 


THE  ELECTRICAL  EXPERIMENTER 


This  department  will  award  the  following  monthly  prizes:     First  Prize,  $3.00;  Second  Prize,  $2.00;  Third  Prize,  $1.00. 

The  purpose  of  this  department  is  to  stimulate  experimenters  towards  accomplishing  new  things  with  old  apparatus  or  old  material, 
and  for  the  most  useful,  practical  and  original  idea  submitted  to  the  Editors  of  this  department,  a  monthly  series  of  prizes  will  be 
awarded.  For  the  best  idea  submitted  a  prize  of  $3.00  is  awarded;  for  the  second  best  idea  a  $2.00  prize,  and  for  the  third  best  prize  of 
$1.00.  The  article  need  not  be  very  elaborate,  and  rough  sketches  are  sufficient.  We  will  make  the  mechanical  drawings.  Use  only  one 
side  of  sheet.    Make  sketches  on  separate  sheets. 


FIRST  PRIZE,  $3.00 

A  NOVEL  ELECTRIC  CHIME. 

The  accompanying  illustration  shows  an 
electric  chime  which  I  have  used  in  place 
of  an  ordinary  vibrating  bell. 


When  the  First  Gong  Strikes,  Its  Dependent 
Armature  Closes  the  Circuit  Thru  the  Sec- 
ond Gong  Magnet  "E",  Etc. 

The  bell  armature  should  be  lengthened 
and  two  contact  points  soldered  to  the  end. 
When  a  button  is  pushed  the  armature  of 
bell  C  is  drawn  over,  striking  the  bell  once. 
The  lower  contact  then  strikes  N  and 
throws  bell  E  in  circuit.  The  armatures 
stay  over  against  the  magnet  as  each  suc- 
cessive bell  is  put  in  circuit,  thus  keep- 
ing the  circuit  thru  lower  contacts  complete. 
When  bell  F  is  rung,  the  battery  circuit 
is  broken,  and  all  the  armatures  fly  back. 
Thus  the  operation  is  repeated.  The  gongs 
should  have  different  tones  to  give  a  pleas- 
.  ing  chime  eff  ect,  and  as  many  bells  can  be 
used  as  desired. 
Contributed  by        A.  G.  CORKRAN. 

"HARD  RUBBER"  BASES  FROM 
"VICTROLA  RECORDS." 

Wishing  to  make  a  detector  and  not  hav- 
ing a  suitable  base  I  procured  a  piece  of  oak 
(any  wood  will  do)  and  an  old  phonograph 
record.  I  cut  the  wood  and  record  to  the 
desired  size.  I  then  put  a  thin  layer  of 
shellac  on  the  wood  and  prest  the  piece  of 
record  on  it,  and  left  it  for  a  few  hours. 
When  it  was  dry  I  sandpapered  the  edges 
and  polished  the  composition  rubber. 


Phonograph  record 
covering 


Do  You  Want  a  Hard-Rubber  Instrument 
Base?  Just  Cut  a  Piece  of  a  "Victrola" 
Record  and  Glue  It  to  a  Wooden  Sub- Base. 

If  the  above  directions  are  followed  very 
neat  bases  can  be  made  by  the  amateur.  If 
the  hole  in  the  record  does  not  allow  a  large 
base  to  be  made,  cut  a  circular  piece  of 
the  composition  rubber  and  plug  it  up. 

Use  records  that  have  one  side  blank. 

Contributed  by  HYMAN  R.  WALLIX. 


SECOND  PRIZE,  $2.00 

SIMPLE  AUTOMATIC  CIRCUIT 
BREAKER. 

The  circuit  breaker  described  below  is 
giving  efficient  service  on  the  switchboard 
in  my  laboratory.  The  pieces  A,  B,  C  and 
D  are  brass  strips ;  E,  is  a  soft  iron  screw 
with  two  nuts  to  fasten  it  to  the  trigger 

C.  F  is  an  electro-magnet  wound  with 
No.  12  silk  insulated  magnet  wire.  The 
core  of  this  magnet  was  obtained  from  an 
electric  bell.  The  spring  G,  and  the  ad- 
justing screw  are  used  to  regulate  the  in- 
strument. The  connections  are  as  shown. 
The  breaker  is  used  on  110  volt  A.C.  or 

D.  C.  lighting  circuit.  When  the  contact 
A  touches  the  contact  B,  it  is  held  there 
by  the  trigger  C.  The  magnet  F  is  always 
magnetized  to  a  certain  extent  but  an 
overload  or  short-circuit  causes  the  mag- 
net to  attract  the  armature  C,  releasing  the 
contact  A,  which  breaks  the  circuit.  It 
is  to  be  manually  reset. 

Contributed  by  ALGIE  RIGGS. 


THIRD  PRIZE,  $1.00 


To  load 


To  line 


© 


In      this      Circuit- Breaker     the  Armature 
Normally   Holds  the  Spring  "A"   Down;  an 
Overload    Causes    the     Magnet    to  Attract 
"E",  Thus  Opening   the  Circuit. 


WALNUT  STAIN. 

The  following  stain  is  excellently  adapted 
to  the  finishing  of  wireless  and  electrical 
cabinets  and  instruments,  and  for  various 
other  wooden  articles  which  is  desired  to 
have  a  uniform  coloring  or  finish. 

Prepare  a  solution  of  6  ounces  of  a 
solution  of  potassium  permanganate,  and  6 
ounces  of  sulfate  of  magnesia  in  2  quarts 
of  hot  water.  The  solution  is  applied  with 
a  brush  and  the  application  should  be  re- 
peated. In  contact  with  wood  the  potas- 
sium permanganate  decomposes,  and  a  last- 
ing walnut  color  results.  If  small  pieces 
of  wood  are  to  be  thus  stained,  a  very  di- 
lute bath  is  prepared  according  to  the 
above  description,  then  the  wooden  pieces 
are  immersed  and  left  in  the  solution  for 
from  1  to  5  minutes,  according  to  whether 
a  lighter  or  darker  color  is  desired. 

Contributed  by 

ALBERT  W.  WILSDON. 


ELECTRIC  FURNACE  MADE  FROM 
PLUMBAGO  CRUCIBLE. 

An  interesting  and  practical  electrical 
furnace  can  be  made  of  a  plumbago  crucible 
(used  by  jewelers)  and  two  gas  carbons. 
One  of  the  carbons  can  be  inserted  in  a 
hole  drilled  about  1^4"  from  the  bottom 
of  the  crucible,  and  the  other  held  in  a 
clamp.    But  some  method  must  be  devised 


THE  SIMPLEST  FLASHLIGHT. 

Here's  the  simplest  flashlight  one  can 
make :    A  flashlight  bulb,  A,  and  battery, 


Hats  Off  to  Mr.   Peterson — Inventor  of  the 
"Simplest"    Electric    Flashlight.      Can  You 
Beat  It? 

and  in  some  cases  a  strip  of  brass,  B,  sold- 
ered to  the  small  battery  terminal  if  it  is 
not  long  enough.  The  lamp  bulb  is  care- 
fully soldered  to  the  longer  terminal  strip. 
The  lamp  is  lighted  by  holding  battery  in 
hand  and  pressing  with  thumb  on  strip  B. 
A  reflector  (a  nickel-plated  thimble  will  do) 
mav  be  fixt  to  the  bulb  if  desired. 

Contributed  by  ERWIX  PETERSON. 

to  start  the  arc — that  is,  to  bring  the  car- 
bons together  and  draw  them  apart.  A 
simple  way  is  to  place  the  crucible  on  a 
long  board,  to  be  used  as  a  lever,  fas- 
tened to  the  base  by  a  hinge  of  leather. 
An  interesting  experiment  can  be  performed 
by  filling  the  crucible  with  ground  glass 
up  to  the  lower  carbon  rod.  An  arc  may 
be  started  between  the  two  gas  carbons, 
and  this  will  heat  the  glass  to  redness. 
An  arc  will  then  be  formed  with  the  car- 
bon rod  and  the  hot  glass  as  electrodes. 


ruses 


Plumbago 
Crucible  \ 


HS1 


110 Volts  A.C 


A  Simple  "Arc"  Furnace  Made  From  Two 
Carbon  Rods  and  a  Plumbago  Crucible. 

The  eyes  should  always  be  shielded  from 
the  intense  light  of  the  arc  by  dark  glasses. 
Contributed  by  TOM  RIEBE. 


Can  you  send  and  receive  at  the 


AMATEURS  ! 
ATTENTION!! 


Now  that  we  are  for  the  time 
being,  deprived  of  using  our 
Radio  outfits,  it  behooves  us  to 
become  proficient  in  learning 
the  Wireless  Codes.  Operators 
who  know  the  Code  are,  and 
will  be,  in  ever  rising  demand. 
The  army  and  navy  need  thou- 
sands of  operators  right  now. 
required   speed,  when  your  country 


Can  you  qualify? 

calls  you? 

The  Radiotone  Codegraph  is  positively  the  only  instrument  made  that  will  send  such 
an  unbelievably  close  imitation  of  a  high  pitch  Radio  Station,  that  it  has  baffled  experts. 
The  outfit  replaces  the  old-fashioned  learner's  outfit,  consisting  of  key  and  sounder.  The 
Radiotone  Codegraph  comprises  our  famous  Radiotone  High  Frequency  Silent  Buzzer,  a 
special  loud  talking  receiver  with  horn,  and  a  key  all  mounted  on  a  base.  Operated  on 
one  or  two  dry  cells,  the  phone  will  emit  the  characteristic  high  pitch  sound,  which  while 
not  harsh,  is  heard  all  over  the  room.  With  little  trouble  you  can  learn  the  code  correctly 
in  30  days —  -   — 7 

AND  THAT  IS  NOT  ALL: 

Connect  two  of  these  outfits  together  for  intercommunication  work  and  you  and  your 
friend  five  or  fifteen  blocks  distant  can  converse  over  a  NO.  36  WIRE,  so  fine  that  no  one 
will  see  it.  Or  you  can  use  instead  of  the  wire,  a  metallic  fence  and  the  ground.  Or  you 
can  communicate  over  your  110  lighting  line,  using  no  extra  wire,  only  the  ground:  Full 
directions  how  to  do  this  are  furnished  with  the  instrument.  DEALERS:  This  is  the  20th 
Century  instrument  that  will  sell  like  WILDFIRE.  600  sold  in  New  York  in  10  days.  Get 
our  proposition  today! 

Radiotone  Codegraph  complete  as  described,  each,    <fc  *|  "TC 
IMMEDIATE  SHIPMENTS  *P  1  •  •  ° 


Selenium  Cells 

Everybody  has  read  about 
the  experiments  of  telepho- 
tography (sending  photo- 
graphs over  a  wire  hundreds 
of  miles)  made  by  Professor 
Korn  and  others.  It  is  also 
known  that  if  the  problem  of 
tele-vision  is  ever  solved,  the 
selenium  cell  will  play  an  im- 
portant role.  At  present  we 
are  the  only  concern  in  the 
United  States  selling  these 
cells.  They  are  the  most  sen- 
sitive ones  made. 

Better  send  for  a  cell  to- 
day and  try  making  an  elec- 
tric dog  that  will  follow  a 
lamp,  or  an  electric  burglar 
alarm.  It's  very  instructive 
and  great  fun.  (See  Novem- 
ber, 1916,  issue  "Electrical 
Experimenter.") 
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Here  Are  the 
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Stripes  in  All 
Their  Glory 

Be  the  first 
one   in  your 
town   to  wear 
this  patriotic 
emblem.  Think 
of  it:  An  elec- 
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the  lapel  hole 
of  your  coat. 
It  illuminates  our  Na- 
tional Flag  in  the  original 
colors  with  a  brilliant  elec- 
tric  light.     Just  insert 
Flag  in  button-hole  of  your 
coat,  put  flashlight  case  in 
vest  or  coat  pocket  and 
every  time  you  press  the 
button,  the   flag   in  your 
button-hole  flashes  up  with 
a  beautiful  color  effect. 


Illuminated  flag,  cord  and  plug  (to  <t  £(\ 

be  connected  to  any  2  cell  flashlight) ,  «P,ou 


(postage  10  cents'). 


Illuminated  flag,  flashlight  case  and  battery,  cord  and  plug,  com- 
plete as  per  illustration,  $1.10  (postage  15c). 
DEALERS  :  Write  for  our  proposition  today. 

IMMEDIATE  SHIPMENTS 


ELECTRO"  TESLA  COILS 


This  photograph  shows  a  seven  (7)  inch  spark. 

Tesla  Coil,  made  by  us  in  our  shops  for  a  well-known  institution. 
We  build  hundreds  of  special  Tesla  Coils  for  schools,  universities,  for 
stage  purposes,  etc.  Spark  lengths  from  two  inches  to  fifteen  inches 
and  over. 

We  are  known  for  careful  workmanship  and  correct  designing.  The 
Tesla  Coil,  shown  above  (7"  spark),  without  condensers  or  spark  gap, 
sells  for  $40.00.  t  Send  for  our  quotations  for  special  coils. 


THE  ELECTRO  IMPORTING  CO. 


No.  HK  1800 


The  "Electro"  Radiotone 

HIGH    FREQUENCY   SILENT   TEST  BUZZER 

The  RADIOTONE  is  NOT  a  mere  test  buzzer, 
it  is  infinitely  more.  Mr.  H.  Gernsback  who  de- 
signed this  instrument  labored  incessantly  to 
produce  an  instrument  which  would  imitate  the 
sound  of  a  high  power  Wireless  station  as  heard 
in  a  set  of  phones.  This  actually  has  been 
achieved  in  the  RADIOTONE.  This  instrument 
gives  a  wonderful  high  pitched  MUSICAL  NOTE 
in  the  receivers,  impossible  to  obtain  with  the 
ordinary  test  buzzer.  The  RADIOTONE  is  built 
along  entirely  new  lines ;  it  is  NOT  an  ordinary 
buzzer,  reconstructed  in  some  manner.  The 
RADIOTONE  has  a  single  fine  steel  reed  vibrat- 
ing at  a  remarkably  high  speed,  adjusted  to  its 
most  efficient  frequency  at  the  factory.  Hard 
silver  contacts  are  used  to  make  the  instrument 
last  practically  forever. 

Yes,  the  RADIOTONE  is  SILENT.  In  fact, 
it  is  so  silent  that  you  must  place  your  ear  on 
top  of  it  to  hear  its  beautiful  musical  note. 

You  will  be  astounded  at  the  wonderfully  clear, 
500  cycle  note,  sounding  sharply  in  your  re- 
ceivers, when  operated  on  one  dry  cell.  To  learn 
the  codes,  there  is  absolutely  nothing  like  it. 
With  the  radiotone,  a  key  and  one  dry  cell  and 
ANY  telephone,  a  fine  learner's  set  is  had.  Two 
or  more  such  sets  in  series  will  afford  no  end  of 
pleasure  for  intercommunication  work.  Particu- 
larly now  that  we  cannot  use  our  Wireless  sets, 
the  Radiotone  is  already  in  wonderful  demand. 
All  the  interesting  things  as  described  with  our 
Radiotone  Codegraph,  elsewhere  on  this  page, 
can  be  performed  with  the  Radiotone,  a  key,  a 
dry  cell  and  a  phone. 

Radiotone  as  described  each  ^.90 

IMMEDIATE  SHIPMENTS 


HERCULES  DYNAMO 


The  Electro 
Hercules  is  a 
dynamo  gener- 
ating^ Volts,  9 
Amperes  (100 
Watts)  and  a 
marvel  of  elec- 
trical or  me- 
chanical effi- 
ciency and  sim- 
plicity. 


It  is  espe- 
cially designed  for  lighting  and  charging  storage 
batteries ;  will  run  18  twelve  volt  lamps  simul- 
taneously. Can  also  be  used  as  a  powerful  mo- 
tor developing  nearly  %  H.P.  Machine  is  shunt 
wound;  size  7  in.  high,  by  11%  in.  long  and 
6%  in.  wide.  It  is  the  cheapest  Dynamo  for  its 
output  on  the  market. 

No.  AGEK  1209.  Electric  Hercules  Dy-tfjl  H  CA 
namo  ;  shipping  weight,  40  lbs.  Price. . .  .«P*  '  •«*" 

We  carry  these  machines  always  in  stock  and 
can  make  immediate  shipment. 


The  "Electro"  Rheostat- Regulator 

(Porcelain  Base) 

This  illustration  represents  our  little  current 
regulator  which  Is  used  everywhere  to  regulate 
batter;  current.  It.  will  prevent  the  burning  out 
of  your  battery  lamps,  or  will  regulate  the  speed 
of  your  small  motors,  and  scores  of  other  uses. 

It  makes  an  excellent  automobile  lamp  dimmer, 
where  it  can  be  used  to  cut  down  the  glare  of  the 
headlights.  This  little  instrument  is  impossible 
to  get  out  of  order.  It  is  constructed  ENTIRELY 
OF  PORCELAIN,  metal  and  hard  rubber. 

The  resistance  of  our  Rheostat  is  10  ohms,  the 
capacity  3  amperes  continually,  size  is  4  inches  in 
diameter;  thickness  of  porcelain  base  is  13/16  ins. 
No.  FK5000  Rheostat  Regulator.  Price  d>  f*f\ 
Shipping  weight,  2  lbs.  <p.OV 
IMMEDIATE  SHIPMENTS 


No.  Fl<  5000 


"Electro"  Pony  Receiver 


Our  Pony  receiver  is 
without  doubt  the  best 
article  for  the  money 
to-day. 

Points  of  superiority  : 
Hard  rubber  composi- 
tion shell  beautifully 
polished.  Powerful  per- 
manent steel  magnet, 
soft  iron  core,  fibre  coil 
heads,  very  thin  dia- 
phragm, brass  posts  in- 
side. Hanger  can  be  un- 
screwed and  receiver 
will  then  fit  our  No. 
AX8077  headbands. 

SOME  USES.  —  For 
all  telephone  work. 
Also  for  making  the 
small  testing  outfits  for  repair  men  in  cir- 
cuit with  only  one  dry  cell  or  flashlight  bat- 
tery. When  connected  in  parallel  with  your 
house  telephone  receiver,  you  have  a  double 
receiver,  an  invaluable  acquisition  to  those 
who  phone  in  noisy  places  or  to  people  hard 
of  hearing.  It  can  also  be  used  for  wireless 
though  its  low  resistance  won't  permit  of 
such  good  results  as  a  higher  resistance 
phone. 

This  receiver  is  single  pole;  214xl%  inches;  wgt. 
4  oz. :  resistance,  75  ohms.  IF  TWO  OF  THESE 
RECEIVERS  ARE  USED,  IT  IS  POSSIBLE  TO 
SPEAK  AT  A  DISTANCE  OF  150  FEET  WITH- 
OUT USING  BATTERIES.  ONE  WIRE  BEING 
SCFFICIHXT  IF  (JROt'.M)  IS  I'SED.  <t-{\  (fl 
No.  EKI024  Pony  Receiver,  75  ohms  «pU.OU 

IMMEDIATE  SHIPMENTS 


No.  El<  1024 


BINDING  POSTS 


No.  B-2 
Each  $0.15 

Shipping 
Weight 
2  lbs.  per  doz. 

These  binding  posts  are  furnished  either  nickel  plated  or  gold  lacquered.  Thev  are  made 
of  first  quality  brass ;  holes  are  accurately  bored,  well  fitting  set  screws,  and  highly  polished. 
Each  post  is  furnished  with  a  %  in.  machine  screw  and  washer  (not  shown  in  illustrations). 
Engravings  are  full  size. 

"The  Livest  Catalog  in  America" 

Our  big,  new  electrical  cyclopedia  No.  18  is  waiting  for 
you.    Positively  the  most  complete  Wireless  and  elec- 
trical catalog  in  print  today.     200  Big  Pages,  600 
illustrations,  500  instruments  and  apparatus,  etc. 
Big  "Treatise  on  Wireless  Telegraphy."    20  FREE 
coupons  for  your  lfiO-page  FREE  Wireless  Course 
in  20  lessons.    FREE  Cyclopedia  No.  18  measures  / 
7x5%".    Weight  Yz  lb-    Beautiful  stiff  covers. 

"THE  LIVEST  CATALOG  IN  AMERICA" 

Now  before  you  turn  this  page  write  your 
name  and  address  on  margin  below,  cut  or 
tear  out,  enclose  6  cts.  stamps  to  cover 
mail    charges,    and   the  Cyclopedia' 
yours  by  return  mail. 

THE  ELECTRO  IMPORTING  CO. 

231  Fulton  Street,  New  York  City, 


31  FULTON  ST.,  NEW  YORK,  N.Y. 


AMATEURS  ! 
ATTENTION!! 


Now  that  we  are  for  the  time 
being,  deprived  of  using  our 
Radio  outfits,  it  behooves  us  to 
become  profii 

the  Wireless  Codes.  Operators 
who  know  the  Code  are,  and 
will  be,  in  ever  rising  demand. 
The  army  and  navy  need  thou- 
sands of  operators  right  now. 
required  speed,  when  your  country 

is  positively  the  only  instrument  made  that  will  send  such 
an  imhrflBvabS  close  Imitation  of  a  high  pitch  Radio  Station,  that  it  has  baffled  experts. 
The ^  outfit  replaces  th^ ToTd-fashioned  learner's  outfit,  consisting  of  key  and  sounder.  The 
Radiotone  Codegraph  comprises  our  famous  Radiotone  High  Frequency  Silent  Buzzer,  a 

not  harsh,  is  heard  all  over  the  room.    With  little  trouble  you  can  learn  the  code  correctly 

AND  THAT  IS  NOT  ALL: 

Connect  two  of  these  outfits  together  for  intercommunication  work  and  you  and  your 
frif-nd  five  or  fifteen  blocks  distant  can  converse  over  a  NO.  36  WIRE,  so  fine  that  no  one 
will  e  it  Or  you  cau  use  instead  of  the  wire,  a  metallic  fence  and  the  ground.  Or  you 
•  your  110  lighting  line,  using  no  extra  wire,  only  the  ground.  Full 
this  are  furnished  with  the  instrument.  DEALERS:  This  is  the  20th 
Century  Instrument  that  will  sell  like  WILDFIRE.  600  sold  in  New  York  in  10  days.  Get 
our  proposition  today! 

Radiotone  Codegraph  complete  as  described,  each.    ^JJ  yg 


Selenium  Cells 

Everybody  linn  read  a  hunt 
tin-  experiments  nf  tclejflio- 
(oprnphy  (s  e  ti  il  I  n  p  photo- 
Graphs  nv,-r  a  win-  h utiiIiv.I.i 
,.f  inll.-s)  made  Liv  I'rof.-ss.ir 
Korn  and  others.  It  Is  also 
It  the  problc 


i  Is 


It's 


in; 


t  fun.  (See 
her,    191H,    Issue  "Electrical 
Experimenter.") 
No.    FX5I7     Selenium  Cell. 
Slil nnlni;" Willi t. "4  $6.00 
IMMEDIATE  SHIPMENTS 


Here  Are  the 
Stars  and 
Stripes  in  All 
Their  Glory 

Be  t  h  e  first 


this  patriotic 
emblem.  Think 
of  it:  An  elec- 
trically illumi- 
nated bouton- 


tbe  lapel  hole 


linates  o  1 
tional  Flag  in  the  original 
colors  with  a  brilliant  elec- 
tric light.  Just  insert 
Flag  in  button-hole  of  your 
coat,  put  flashlight  case  in 
vest  or  coat  pocket  and 
every  time  you  press  the 
button,  the  flag  In  your 
button-hole  flashes  up  with 
a  beautiful  color  effect. 


"ASK  $-60 


Illuminated  flag. 

bt  cuiiiii'ck'd  tij  uny  2  c 

Illuminated  flao,  flashlight  ease  and  battery,  cord  and  plug,  c 
plete  as  per  Illustration,  SI.10  (postage  15c). 

DEALERS  :  Write  for  our  proposition  today. 

IMMEDIATE  SHIPMENTS 


"ELECTRO"  TESLA  COILS 

This  photograph  shows  a  seven  (7)  inch  spark. 

Tcsla  Coil,  medo  by  us  In  our  shops  for  a  well-known  Instilutlnr 
We  uulld  hundreds  of  sin-Hal  Ttslo  Culls  for  srlinuls,  universities,  fi: 
stuco  purposes,  etc.    Spark  lenelhs  from  two  Indies  to  fifteen  lnelit 


Wo  tiro  known  fr.r  \ 
Teala  Coil.  sho< 
sells  for  S40.00.  ' 


Parents: 

No.84Z.S50 

FebS,  1907 

0ct^l908 
No.948,1175 
Feb!.  1910 

No.95l.76S 
Mar.6,1910 


No.961,655 
dune  2 1. 1910 

No.976,999 
Dec  £0,1910 


No  366,45  & 
April  4.191 1 

No  988,767 
April  4.191 1 

No  1,016,138 
clan30.l9l£ 

No  1033,095 
duly  £5.1912. 

No  1,051810 
April  1. 1913 

No  \)l4fi\5 
Jan  12.. 1915 

No  94.990 
dan,  ZO.  1911 

8Pe.Unts 
Pending  ir> 
Rsient  Office 


ireful  workmanship  and  correct  deslgnlni 
.park),  without  condensers  or  spai 
our  quotations  far  special  colls. 


THE  ELECTRO  IMPORTING  CO. 


The  "Electro"  Radiotone 

HIGH    FREQUENCY   SILENT  TEST  BUZZER 

Tho  RADIOTONE  Is  NOT  n  mere  test  buzzer. 
It  Is  Infinitely  more.  .Mr.  H.  Gernsback  who  de- 
signed this  instrument  labt.rid  Incessantly  !o 

produco  an  lnstrui  it  e.lii.h  »..iild  Imitate  tho 

sound  of  a  hlph  poncr  Wireless  station  as  heard 
of  phones.  Thls_ 


ichlov 


I  In  the  HAMOTHNE      This  liismmn-nt 
wonderful  hluh  |.lt .  li.i]  Ml  SH  At,  NOTE 
the  receivers,  Iiii|i..s-.II.I.-  t.>  ..Main  with  tho 
""      HAMOTONE  Is  built 
Is  NOT  an  -.r.Hn.iry 


alonp  entirely  new  lines; 

buzzer,  reconstructed  In  some  manner.  uiu 
RADIOTONE  lias  a  single  tin.'  steel  reed  vlhrat- 
Inp  at  a  remarkably  liliili  sine. I,  adjusted  In  Its 
most  efficient  frequency  at  the  factory.  Hard 
silver  contacts  arc  used  to  make  the  Instrument 
last  practically  forever. 

Yes.  the  RADIOTONE  Is  SILENT.  In  fact, 
it  Is  so  silent  that  you  must  place  your  car  on 
lop  of  It  to  bear  Its  beautiful  musical  note. 

You  will  be  astounded  at  the  wonderfully  clear. 


pleasure  fur  lut.-r--.ir  

larly  ii. iw  that  wo  cam 
tin:  Radiotone  Is  alrein 
All  the  Interesting  thin 
Radiotone  Codearanti, 
can  be  performed  with 
dry  cell  and  a  phone. 


$.90 


HERCULES  DYNAMO 


Tho  Electro 
Hercules  Is  a 
dynnmo  gener- 
ating^ Volls.  0 
Amperes  (100 
Walts)  and  a 
marvel  of  clec- 

.h.mi.al 


as  a  powerful  ino- 
f..r  developing  nearly  Vi  11.1'.  Machine  Is  shunt 
wound;  size  7  In.  hlch.  by  11%  l»-  lone  and 
CMi  In.  wide.  It  Is  the  cheapest  Dynamo  for  Its 
output  on  the  market. 

AGEK  1209.  Electric  Hercules  nV-$17JjQ 


We 


shipping  weight.  40  lbs.  Price.. 

lachlnos  always  in  stock  a 


The  "Electro"  Rheostat- Regulator 


No.  Fl<  5000 


'Electro*'  Pony  Receiver 


llnr  I'o 
aril. In  f. 


\  of  superiority : 
■ubbcr  composl- 
■  ■II  beautifully 


:-i.l.'.     II. Ill);, -1-  .Mil  In' 

screwed    ;i  u  d  recel 
ulll    Ih.-n    fit  our 
AXsn;:  h.  miMiuiuIs. 

SOME  USES.  —  P 
all  telephone  work.  u.  EK 
Also  for  making  the 
sini.ll  testlnc  ..milts  f..r  repair  men  in  cir- 
cuit with  only  .me  drv  .-,.■11  ..r  flashlight  bat- 
tery. When  connected  In  parallel  with  your 
house  telephone  receiver,  v.ui  have  a  double 
receiver,  an  ln\ ..lu.ii.l.-  a.-.|uisltlon  to  those 
who  phono  In  noisy  places  nr  to  people  hard 
of  hearing.  It  can  also  be  used  for  wireless 
thoup.li  Us  low  resistance  won't  permit  of 
such  pood    results    as    a   higher  resistance 


-  In  1-1.. 


$0.50 


These  binding  . 
of  tlrsl  quality  brass :  holes  a 
Each  post  Is  furnished  with  a 
Engravings  are  full  si ze. 


furnished  either  nickel  [il.ited  nr  t'nl.l  lar.iuere.l  They  are  made 
■atcly  bored,  well  lilting  set  sere»s.  mid  highly  polished, 
machine  screw  and  washer  (not  shown  In  Illustrations). 


'The  Livest  Catalog  in  America' 


tlnr  hip,  new  electrical  cyclopedia  No.  18  Is  waitlnp 
yon.  rosltlvely  the  must  .  < unpick-  Wireless  and  eh 
trii-al  ralalnp  in  print  today.  200  Big  Pages,  6l 
llliislr.il  I. >iis.  ".nil  in^trunn-nts  and  apparatus,  elc 
Big  "Treatise  on  Wireless  Telegraphy."    20  FREE 

,i,iil  s  f..r  v.iiir  Hin-|.npc  Kit  EE  Win-less  Course- 

In  -m  lessons.  Kit  EE  t  y.-|. .pedla  N...  IX  measures 
7x514".  Weight  Vt  lb-  Beautiful  stiff  covers. 
"THE  LIVEST  CATALOG  IN  AMERICA' 
Now  before  you  turn  this  page  write  your 
namo  and  address  mi  margin  below,  cut  or 
tear  out,  enclose  f.  cts.  stamps  to  cover 
mall  charges,  and  the  Cyclopedia  la 
yours  by  return  mall. 

THE  ELECTRO  IMPORTING  CO. 
231  Fulton  Street,  New  York  City, 


231  FULTON  ST.,  NEW  YORK,  N.  Y.  ^ 


122 


THE  ELECTRICAL  EXPERIMENTER 


June,  1917 


A  NOISELESS  "ALARM"  CLOCK. 
By  K.  M.  Coggeshall. 

Have  you  ever  stopt  to  wonder  what 
your  friend  in  the  next  room  thinks  when 
your  discordant  alarm  clock  rings  each 
morning?    Have  you  ever  wisht  you  had 


Did  You   Ever  Hear  of  a  "Silent"  Alarm  C 
Here's  One.     It  Awakens  You   by  Flashing 
Light  on  Your  Face.     Try  It. 

some  method  of  waking  yourself  without 
disturbing  your  neighbors?  Perhaps  you 
may  arise  at  five-thirty  in  the  morning  while 
the  rest  of  the  household  do  not  find 
the  necessity  of  opening  their  eyes  un- 
til six-thirty.  Perhaps  some  one  may  be 
ill  and  you  wish  to  awake  during  the  night 
to  give  him  medicine,  and  yet  do  not  like  to 
disturb  anyone  else  who  may  be  asleep. 
Again  you  may  be  looking  forward  to  a 
before-dawn  start  on  a  fishing  expedition 
but  out  of  respect  to  others  you  dislike  to 
resort  to  the  alarm  clock  to  awaken  you. 

To  overcome  these  objections  to  the  or- 
dinary alarm  clock,  the  following  apparatus 
was  designed  to  awaken  one  sleeper  with- 
out disturbing  the  rest  of  the  household. 

A  box-like,  wooden  sub-base  was  built 
as  shown  in  the  sketch.  In  its  face  a  round 
hole  was  cut  and  into  this  was  fitted  an  or- 
dinary bicycle  spot  light.  A  single  pole, 
single  throw  knife  switch  was  screwed  to 
the  upper  inside  surface  of  the  sub-base. 
The  lamp  was  then  connected,  thru  the 
switch,  to  a  battery  of  sufficient  capacity  to 
utilize  its  full  candle-power.  If  the  sub- 
base  is  made  large  enough  the  battery  may 
be  enclosed  and  the  entire  outfit  made  com- 
pact and  portable. 

The  bell,  as  well  as  the  striker,  was  re- 
moved from  an  alarm  clock.  A  thread 
spool  was  attached  to  the  alarm  winding 
key  to  serve  as  a  drum  on  which  the  cord 
to  operate  the  switch  was  to  wind.  This 
switching  device  was  very  simple.  A  strong 
cord  was  attached  to  the  handle  of  the 
knife  switch,  brought  up  thru  a  hole  in  the 
base  and  attached  to  the  spool  on  the  wind- 
ing key. 

The  mechanical  operation  of  this  device 
can  well  be  imagined.  The  apparatus  is  set 
on  the  mantel  or  dresser  in  the  bedroom. 


rived,  the  alarm  mechanism  operates,  turn- 
ing the  drum,  thus  winding  in  the  cord, 
which  in  turn  closes  the  switch  and  lights 
the  lamp.    All  this  will  be  accomplished 
noiselessly.    No  one  can  sleep  with  a  bright 
beam  of  light  suddenly  directed  onto  the 
face.    Furthermore,  it  is  im- 
possible to  snatch  a  few  cat- 
naps before  getting  up  with 
this  light  in  the  eyes.    It  is 
therefore  imperative  that  the 
awakened    person    arise  and 
open  the  controlling  switch — 
and  once  out  of  bed  there  is 
little  danger  of  dropping  off  to 
sleep  again. 

ELECTRIC  LIGHT  FOR 
GUN  SIGHTS  AT  NIGHT. 

As  every  hunter  knows,  it  is 
extremely  difficult  to  aim  cor- 
rectly at  night,  even  tho  the 
lock? — Well,      game  can  be  seen,  for  the  sim- 
a  Beam  of      ple  reason  that  the  gun  sights 
on  the  barrel  cannot  be  ac- 
curately viewed. 

The  accompanying  illustration  shows  how 
a  small,  frosted,  flashlight  bulb  may  be 
placed  just  behind  the  forward  sight,  with 
a  metallic  shield  over  it,  so  as  not  to  throw 
a  glare  in  the  gunner's  eyes.  It  is  a  simple 
matter  to  bore  a  hole  in  the  wooden  stock 
of  the  gun  with  an  ordinary  carpenter's 
brace  and  bit,  in  which  to  mount  a  cell  or 
two  from  a  flashlight  battery,  the  size  of 
these  individual  cells  being  about  l-54"x7/16" 
in  diameter.  Also  the  cells  may  be  placed  in 
a  brass  or  fibre  tube  secured  under  the 


A 'I arm  trey 
w/fi  spool 
drttm afldttied 


Stno/I  spofl/ghf  sue/?  as 
used  on  D/cc/c/e 


dactrofspof 
//g/tf  @ 


How  an  Ordinary  Alarm  Clock  Is  Rigged  Up 
So  as  to  Close  the  Lamp  Circuit  of  the  "Si- 
lent Alarm." 

The  spot  light  is  then  so  adjusted  that  the 
full  power  of  the  light  ray  will  concentrate 
on  the   face   of  the   sleeper.    The  alarm 
should  be  wound  and  adjusted  as  usual. 
When  the  predetermined  hour  has  ar- 


feolomp 


JjteQ Grounded 


A  Tiny  Electric  Light  Fixt  Just  Back  of  the 
Forward  Sight  Proves  a  Boon  to  the  Hunter 
at  Night. 

fore-arm  section  of  the  gun  frame.  A 
switch,  of  unobtrusive  proportions,  will 
serve  to  light  the  lamp  bulb  when  wanted. 

H.  G. 


GOOD  INK  FORMULAE. 

These  two  formulae  obtained  thru  orig- 
inal experiments,  have  been  found  to  pro- 
duce excellent  inks.  The  ingredients  are 
easily  obtained  and  at  little  expense.  Rain 
water  may  be  used  in  place  of  distilled 
water  thus  removing  the  need  of  having 
any  chemical  apparatus.  The  resulting  inks 
are  each  of  a  beautiful  color,  make  a  per- 
manent record,  flow  easily,  and  do  not 
corrode  the  pens.  The  blue  ink  can  be 
used  successfully  and  safely  in  the  most 
delicate  of  fountain  pens. 

Blue  Ink:  Dissolve  one  ounce  of  soluble 
Prussian  blue  in  one  quart  of  cold  dis- 
tilled (rain)  water.  Add  to  this  solution, 
5  grams  of  oxalic  acid.  Then  filter  the 
solution  thru  filter  or  blotting  paper. 

Black  Ink:  Dissolve  one  ounce  of  ex- 
tract of  logwood  in  one  quart  of  boiling 
water.  When  cold,  add  one-fourth  ounce 
of  potassium  bichromate  and  one  gram  of 
sodium  carbonate.  The  addition  of  one- 
fourth  ounce  of  prussian  blue  improves  the 
solution.    This  ink  will  cost  about  5  cents. 

Contributed  by 

CLARENCE  S.  LEVINE. 


STATIC  EXPERIMENTS  WITH 
LAMP  BULB. 

Materials  needed — 1  or  more  burned-out 
electric  light  bulbs. 


Experiment — Take  the  bulb  and  hold 
it  near  a  rapidly  moving  belt,  connected 
with  machinery  which  is  not  grounded. 
Hold  the  brass  end  of  the  bulb  close  to  the 


Hold  an  Incandescent  Lamp  Bulb  Near  a 
Rapidly  Moving  Belt — Usually  Sufficient 
Static  Electricity  Will  Pass  to  Charge  the 
Lamp  as  a  Condenser.  It  Will  Give  Power- 
ful Shocks. 

belt  and  sparks  will  usually  jump  from  the 
belt  to  the  brass  cap. 

Charge  in  this  manner  for  about  five  min- 
utes, then  take  it  away.  Offer  it  to  some- 
one, holding  the  bulb  by  the  glass  end  al- 
ways. When  the  person  goes  to  touch  the 
brass  end  a  nice  hot  spark  will  jump  to 
him,  giving  a  considerable  shock. 

Contributed  by        R.  G.  DEVANEY. 

KNICK-KNACKS  FOR 
"RADIO-BUGS." 

By  placing  one  of  the  E.  I.  Co.'s  load- 
ing coils  against  the  end  of  a  small  loose 
coupler,  I  have  been  able  to  catch  stations, 
using  up  to  6,000  meters,  this  being  done 
without  additional  inductance  in  the  sec- 
ondary, built  for  only  800  meters. 

Most  loose  couplers  have  the  primary 
tube  placed  in  grooves  cut  in  the  heads  and 
by  turning  it,  a  new  surface  is  obtained 
for  the  slider.  Clean  the  path  of  the 
slider  occasionally  with  a  rubber  pencil  or 
ink  eraser. 

Use  Solderall  on  the  next  loose  coupler 
you  build  and  you  will  use  no  other. 

Contributed  by        ASA  S.  KELLER. 


AUTOMATIC  LIGHT  SWITCH  FOR 
CLOSETS. 

Herewith  is  a  drawing  of  a  little  device 
I  made  from  scrap  materials  and  which 
has  proved  very  efficient. 

It  is  intended  to  automatically  close  an 
electrical  circuit  on  opening  the  door  of 
a  dark  closet  or  unlighted  room,  and  by 


( 9rush  i 


TS7  T-55*^ 

Support 
Brass  rod 


Spring  under, 
tension  irnen  aoor 
ts  c/osed 
lubing  soldered  to,  - ' 
support  -~ 

-lamp 


A    Reliable    Automatic    Switch    for  Closet 
Light.    When  Door  Opens  the  Switch  Rod  Is 
Moved  Forward  by  the  Spiral  Spring  as  Be- 
comes Evident,  and  Vice-versa. 

means  of  a  small  battery  and  lamp  illum- 
inate the  interior. 

As  the  illustration  shows,  the  materials 
and  construction   are   exceedingly  simple. 

Contributed  by        H.  W.  WALTER. 


June,  1917 


THE  ELECTRICAL  EXPERIMENTER 

Experimental  Chemistry 


23 


ACIDS,  BASES  AND  SALTS. 

(Continued) 
S  stated  in  the  previous  installment, 
the  basicity  of  acids  are  determined 
by  the  number  of  hydrogen  atoms 
[replaceable  by  a  metal]  in  its 
molecule.  Thus  :  Mono-basic  acids 
contain   one   hydrogen   atom,    as  Hydro- 


K 


It  Is  Always  Best  to  Stir  Solutions  with  a 
Glass  Rod.     Have  a  Clean  Vessel  for  Each 
Acid    if   You    Would    Achieve  Satisfactory 
Results. 

chloric  acid  [HQ],  from  which  only  one 
replacement  is  possible.  Di-basic  acids 
contain  two  hydrogen  atoms,  as,  Sulfuric 
acid  [H2SO4],  from  which  two  replace- 
ments are  possible.  Tri-basic  acids  contain 
three  hydrogen  atoms,  as  Phosphoric  acid 
[H3PO-1],  from  which  three  replacements 
are  possible.  Tetra-basic  acids  contain  four 
hydrogen  atoms,  as,  Normal  Silicic  acid 
[HiSiOi].  [Note:  Normal  Silicic  acid 
readily  parts  with  half  of  its  water,  leaving 
H:Si03,  also  called  Silicic  Acid],  from 
which  four  replacements  are  possible. 
Penta-basic  acids  contain  five  hydrogen 
atoms,  as  Periodic  acid  [HJOs],  from 
which  five  replacements  are  possible. 

The  higher  the  basicity  of  the  acid  the 
greater  the  variety  of  salts  it  can  yield. 

If  we  take  the  base  Potassium  Hydroxid 
to  illustrate  the  replacement  of  the  hydro- 
gen of  the  acids,  we  find  that  Nitric  acid 
or  Hydrochloric  acid  can  form  but  one 
salt  with  Potassium  Hydroxid,  the  reac- 
tions being: — 

KOH      +  HNO; 
Potassium 
Hydroxid 

and 

KOH  4-        HC1  =      KC1  4- 
Potassium       Hydrochloric  Potassium 
Hydroxid            Acid  Chlorid 

Other  acids  have  the  power  to  form  two 
or  more  salts  with  the  same  base. 

If  only  half  the  quantity  of  base  that  is 
required  to  neutralize  the  acid  is  added, 
half  the  acid  remains  unchanged,  and  on 
evaporating  the  solution,  the  excess  acid 
will  pass  off.  If  only  half  the  quantity  of 
acid  that  is  required  to  neutralize  the  base 
is  added,  half  the  base  will  remain  un- 
changed. Sulfuric  acid  [H2S04]  has  been 
found  to  have  the  power  to  form  two  salts 
with  Potassium  Hydroxid  [KOH],  in  one 
of  which  there  is  twice  the  amount  of  the 
metal  as  in  the  other.    The  reactions  being : 

KOH     4.    H2SO4    =       KHS04     4-  H20 
Potassium 
[acid]  Sulfate 


=      KNO3  4- 
Potassium 
Nitric  Acid  Nitrat 


H.O 
Water 


H20 
Water 


Water 


4-  H„0 
Water 


Potassium  Sulfuric 
Hydroxid  Acid 

and  again : — 

2K0H     +     H2SOi  =  K,S04 
Potassium          Sulfuric  Potassium 
Hydroxid  .           Acid  Sulfate 

If  to  a  certain  quantity  of  Sulfuric  acid 
only  half  the  quantity  of  Potassium  Hy- 
droxid that  is  required  to  neutralize  it  is 
added,  the  first  reaction  takes  place ;  but 
if  twice  as  much  Potassium  Hydroxid  is 


By  ALBERT  W.  WILSDON 
Thirteenth  Lesson 

used,  the  second  takes  place.  An  acid  of 
this  kind  can,  further,  form  one  salt  with 
two  bases,  in  which  one  metal  is  sub- 
stituted for  one  of  the  hydrogen  atoms  of 
the  acid  and  a  second  metal  for  the  other. 

As  aforementioned,  in  the  molecule  of 
Hydrochloric  acid  [HQ]  as  in  Nitric  acid 
[HNO.i],  there  is  but  one  atom  of  hydro- 
gen. If,  therefore,  the  act  of  neutraliza- 
tion takes  place  in  each  molecule  it  is  com- 
plete, and  the  salt  is  known  as  a  neutral  or 
normal  salt.  In  Sulfuric  acid  [H2SO(] 
there  are  two  atoms  of  hydrogen  in  each 
molecule,  and  either  one  or  both  of  these 
atoms  may  be  replaced.  If  only  one  is  re- 
placed a  salt  having  the  general  formula, 
MHSO4,  is  obtained.  This  is  still  an  acid, 
while  it  is  also  partly  a  salt.  This  is  known 
as  an  Acid  Salt. 

It  may  be  difficult  for  some  readers  to 
associate  the  names  Monobasic,  Dibasic, 
Tribasic,  Tetrabasic,  etc.,  with  the  basicity 
of  the  acids,  but  as  these  names  represent 


Method  of  Pouring  Small  Quantities  of  Acid 
onto  a  Glass  Rod  so  That  They  Drop  into  a 
Beaker  or  Other  Dish  Easily. 

the  number  of  hydrogen  atoms  in  the  mole- 
cule, it  may  be  well  to  memorize  the  fol- 
lowing : 


tvoporaf/ng 
d/sh  \ 


Jsbesfos  or 
wire  gauze 


large  r/ng 
■'support 


f/g  67 


Correct  Manner  in  Which  to  Place  "Evap- 
orating   Dish,"    Wire    Gauze    and  Bunsen 
Burner. 

The     prefix     Mono —     means  one 
Di—  "  two 

"  Tri —  "  three 

Tetra —  four 
Penta —  five 
Thus,  when  speaking  on  monobasic  acids, 
by  remembering  that  mono —  means  one, 
and  when  associated  with  the  basicity  of 
an  acid,  mono —  meaning  one,  and  the 
basicity  being  the  number  of  hydrogen 
atoms,  we  can  thus  see  that  monobasic 
means  one  hydrogen  atom. 

EXPERIMENT  NO.  54— 

Have  two  small-lipt  beakers,  or  two  test 
tubes,  one  of  which  will  contain  10  cc. 
of  a  solution  of  Sodium  Hydroxid  [NaOH] 
and  the  other  an  equal  quantity  of  Hydro- 
chloric acid    [HQ].    Pour  5   cc.   of  the 


Sodium  Hydroxid  solution  in  an  evaporat- 
ing dish,  and  immerse  in  it  a  piece  of  blue 
litmus  paper,  allowing  it  to  remain  in  the 
solution.  Pour  small  quantities  of  Hydro- 
chloric acid  from  the  beaker  onto  a  glass 
rod,  allowing  it  to  drop  into  the  evaporat- 
ing dish,  in  the  manner  shown  by  Fig.  66, 
stirring  the  mixture. 

It  will  be  noticed  that  the  litmus  paper 
will  probably  turn  red,  owing  to  the  fact 
that  the  solution  has  too  much  acid  con- 
tained in  it.  If  such  is  the  case,  add  a 
little  more  Sodium  Hydroxid,  by  allow- 
ing to  drop  from  a  stirring  rod  in  the 
same  manner  as  described  for  the  acid.  If 
too  much  of  the  Hydroxid  is  added  the 
litmus  paper  might  again  turn  to  a  blue 
color,  and  if  this  happens,  add  a  little  more 
of  the  acid,  drop  by  drop,  till  the  liquid 
becomes  neutral  to  the  litmus  paper.  It 
may  be  necessary  to  keep  adding  either  the 
Acid  or  the  Hydroxid.  Introduce  another 
piece  of  red  litmus  when  you  think  the 
solution  is  neutral,  and  if  it  is  unaffected, 
immerse  another  piece  of  blue  litmus  paper 
in  it,  and  then  if  the  solution  does  not 
affect  either  the  red  or  blue  paper  it  is 
neutral.  If  the  solution  is  not  clear  after 
it  has  been  neutralized,  filter  it,  and  throw 
away  all  but  about  15  cc.  of  it. 

Place  the  15  cc.  of  the  solution  obtained 
into  an  evaporating  dish,  and  place  on 
either  a  piece  of  line  meshed  iron  gauze 
or  a  piece  of  asbestos  pad,  as  shown  in 
Fig.  67.  Apply  a  light  to  the  Bunsen 
burner  under  the  evaporating  dish,  and  al- 
low the  liquid  to  evaporate  [boil]  till  a 
white  solid  is  formed,  or  in  other  words 
till  all  the  water  has  been  driven  from 
the  original  solution. 

The  equation  of  the  reaction  which  took 
place  between  the  Sodium  Hydroxid  and 
the  Hydrochloric  acid  when  neutralized 
was : — 

NaOH     4.        HC1         =    NaCl     -!-  H=0 

Sodium  Hydrochloric  Sodium  Water 
Hydroxid  Acid  Chlorid 

We  perceive  from  this  equation,  that  the 
hydrochloric  acid  no  longer  is  contained 
in  the  solution,  and  that  the  Sodium  [Na] 
of  the  base  exchanged,  or  replaced  the 
hydrogen  of  the  acid,  forming  a  salt  and 
water. 

EXPERIMENT  NO.  55— 

In  the  same  manner  as  described  in  the 


If  Two  or  More  Liquids  Which  Have  Differ- 
ent Densities  and  Will  Not  Mix  Are  Poured 
into  a  Jar,  They  Will  Come  to  Rest  in  the 
Order  of  Their  Densities,  with  the  Surfaces 
of  Each  Separating  .  Them  Horizontally. 
Mercury,  Water,  Oil  and  Alcohol,  When 
Poured  in  a  Test  Tube,  Will  Come  to  Rest 
in  the  Order  Named. 

preceding  experiment,  prepare  a  solution 
of  both  Potassium  Hydroxid  and  Hydra- 
te C ontinued  on  Page  127) 


THE   ELECTRICAL  EXPERIMENTER  June,  1917 


124 


Under  this  heading-  we  _  will  publish  every 
month  useful  information  in  Mechanics,  Elec- 
tricity and  Chemistry.  We  shall  be  pleased,  of 
course,  to  have  our  readers  send  us  any  recipes, 
formulas,  wrinkles,  new  ideas,  etc.,  useful  to  the 
experimenter,  which  will  be  duly  paid  for,  upon 
publication,  if  acceptable. 


FREEZING  MIXTURES. 

When  ice  or  snow  are  not  to  be  had  and 
for  those  of  us  who  do  not  have  an  up-to- 
date  laboratory  that  is  provided  with 
agencies  of  cooling  power,  I  am  sure  the 
following  mixtures  will  prove  most  con- 
venient. 

1.  Nitrat  of  ammonia,  carbonat  of  soda 
and  water,  equal  parts  by  weight ;  the  ther- 
mometer sinks  57°. 

2.  Phosfate  of  soda,  9  parts ;  nitrat  of 
ammonia,  6  parts;  dilute  nitric  acid  (acid 
1  part,  water  2  parts),  4  parts.  Reduces 
the  temperature  from  50°  to  21°. 

3.  Sal-ammoniac,  5  parts;  nitrat  of  pot- 
ash, 5  parts;  sulfate  of  soda,  8  parts; 
water,  16  parts.  Reduces  the  temperature 
46°  or  from  70°  to  24°.  This  latter  is  very 
cheap  and  easily  procured. 

If  you  have  ice  and  wish  to  reduce  the 
temperature  still  further,  use  the  follow- 
ing : 

1.  Finely  pounded  ice,  2  parts ;  salt,  1 
part.    This  is  a  very  common  recipe. 

2.  Finely  pounded  ice,  2  parts  ;  crystal- 
lized chlorid  of  calcium,  3  parts. 

3.  Finely  pounded  ice,  7  parts ;  dilute 
nitric  acid,  4  parts.  This  reduces  the  tem- 
perature from  32°  to  30°.  The  tempera- 
tures given  are  Fahrenheit.  The  materials 
should  be  kept  as  cool  as  possible. 

Contributed  by         MINARD  ROTE. 


SOLUTION   FOR   MAKING  WORK 
TABLE  IMPERVIOUS  TO  ACID 
AND  ALKALI  SOLUTIONS. 

Doubtless,  many  experimenters,  especially 
those  working  with  the  various  chemical 
reagents,  desire  some  coating  for  the  work 
table  that  is  impervious  to  both  acid  and 
alkali  solutions.  The  writer  has  used  the 
following  method  in  his  laboratory  with 
decided  success,  and  heartily  recommends 
it  to  those  who  desire  a  similar  formula. 

Two  solutions  are  to  be  made : 

Solution  1.  Iron  sulfate,  4  parts;  copper 
sulfate,  4  parts;  potassium  permanganate, 
8  parts ;  water,  100  parts. 

Solution  2.  Aniline,  12  parts ;  hydro- 
chloric acid,  18  parts ;  water,  100  parts,  or 
aniline  hydrochlorat,  15  parts;  water,  100 
parts. 

Apply  two  coats  of  solution  No.  1,  while 
hot,  applying  the  second  coat  as  soon  as  the 
first  has  dried.  After  solution  No.  1  has 
dried,  the  excess  of  solution  which  has 
dried  upon  the  surface  of  the  wood  is 
thoroly  rubbed  off  before  the  application 
of  solution  No.  2. 

Next,  two  coats  of  solution  No.  2  are 
applied,  and  the  wood  permitted  to  dry 
thoroly.  The  black  color  does  not  appear 
at  once,  but  requires  a  few  hours  before 
turning  to  a  rich  ebony-black  color.  Later 
a  coat  of  raw  linseed  oil  is  to  be  applied 
with  a  cloth. 


RECIPES  FOR  KILLING  FLIES. 

The  United  States  Government  makes 
the  following  suggestion  for  the  destruc- 
tion of  house  flies :  Formaldehyde  and 
sodium  salicylate  are  the  two  best  fly  poi- 
sons. Both  are  superior  to  arsenic.  They 
have  their  advantages  for  household  use. 
They  are  not  a  poison  to  children ;  they  are 
convenient  to  handle ;  their  dilutions  are 
simple,  and  they  attract  the  flies. 

Preparation  of  Solutions : — A  formalde- 
hyde solution  of  approximately  the  cor- 
rect strength  may  be  made  by  adding  3 
teaspoon fuls  of  the  concentrated  formalde- 
hyde solution,  commercially  known  as  for- 
malin, to  a  pint  of  water.  Similarly,  the 
proper  concentration  of  sodium  salicylate 
may  be  obtained  by  dissolving  3  teaspoon- 
fuls  of  the  pure  chemical  (a  powder)  to 
a  pint  of  water. 

A  container  such  as  shown  below  has 
been  found  convenient  for  automatically 
keeping  the  solution  always  available  for 
flies  to  drink.  An  ordinary,  thin-walled 
drinking  glass  is  filled  or  partially  filled 
with  the  solution.  A  saucer,  or  small  plate, 
in  which  is  placed  a  piece  of  white  blot- 
ting paper  cut  the  size  of  the  dish,  is  put 
bottom  up  over  the  glass.  The  whole  is 
then  quickly  inverted,  a  match  placed  under 
the  edge  of  the  glass,  and  the  container  is 


Now  That  the  "Fly  Season"  Is  With  Us,  the 
Non-Poisonous  (to  Humans)  Wet  Blotter  Fly 
Annihilator  Shown,  Which  Is  Recommended 
by  the  U.  S.  Government,  Should  Prove 
Particularly  Valuable. 


ready  for  use.  As  the  solution  dries  out 
of  the  saucer  the  liquid  seal  at  the  edge  of 
the  glass  is  broken  and  more  liquid  flows 
into  the  lower  receptacle.  Thus  the  paper 
is  always  kept  moist. 

Other  Simple  Preventives :— Any  odor 
pleasing  to  man  is  offensive  to  the  fly  and 
vice  versa,  and  will  drive  them  away. 

Take  five  cents'  worth  of  oil  of  lavender, 
mix  it  with  the  same  quantity  of  water, 
put  it  in  a  common  glass  atomizer  and 
spray  it  around  the  rooms  where  flies  are. 
In  the  dining-room  spray  it  lavishly  even 
on  the  table  linen.  The  odor  is  very  dis- 
agreeable to  flies  but  refreshing  to  most 
people. 

Geranium,  mignonette,  heliotrope  and 
white  clover  are  offensive  to  flies.  They 
especially  dislike  the  odor  of  honeysuckle 
and  hop  blossoms. 

According  to  a  French  scientist,  flies  have 
intense  hatred  for  the  color  blue.  Rooms 
decorated  in  blue  will  help  to  keep  out  the 
flies. 

Mix  together  one  tablespoonful  of  cream, 
one  of  ground  black  pepper  and  one  of 
brown  sugar.    This  mixture  is  poisonous 


The  tables  are  cleaned  very  easily  by 
washing  with  water  or  suds  after  any  work 
is  finished,  and  the  application  of  another 
coat  of  oil  puts  them  in  excellent  order 
for  another  experiment. 

Contributed  by 

ALBERT  W.  WILSDON. 


to  flies.  Put  in  a  saucer,  darken  the  room 
except  one  window  and  in  that  set  the 
saucer. 

To  clear  the  house  of  flies,  burn  pyre- 
thrum  powder.  This  stupefies  the  flies,  but 
they  must  be  SWEPT  UP  and  BURNED. 

Reccipcs  for  Stables,  Barns  and  Out-of- 
doors: — Borax  is  especially  valuable  around 
farms  and  out-of-doors.  One  pound  of 
borax  to  twelve  bushels  of  manure  will 
be  found  desirable  as  a  poison  without  in- 
juring its  manurial  qualities  on  farm  stock. 
Scatter  the  borax  over  the  manure  and 
sprinkle  with  water. 

Lye,  chlorid  of  lime,  or  copperas  (sul- 
fate of  iron)  dissolved  in  water,  crude  car- 
bolic acid,  or  any  kind  of  disinfectant  may 
be  used  in  vaults. 


HEKTOGRAPHS. 

What  are  they,  do  you  ask?  The  Cen- 
tury Dictionary  defines  it  as  follows :  "A 
copying  process  in  which  the  writing  or 
drawing  to  be  copied  is  made  on  smooth 
paper  in  aniline  ink,  and  is  then  prest 
upon  a  slab  coated  with  gelatin,  to  which  a 
part  of  the  ink  is  thus  transferred,  and 
from  which  a  number  of  duplicate  impres- 
sions can  be  made ;  also,  the  special  ap- 
pliances, collectively,  by  means  of  which 
this  is  done."  The  chance,  however,  is 
that  you  do  not  want  any  definition,  but 
might  like  some  directions  for  simplifying 
the  process,  which  some  teachers  and  stu- 
dents who  want  a  number  of  copies  of  text 
oi  drawing,  are  using  successfully.  Agree- 
able to  this  contingency,  we  have : 

Receipt  No.  1. — Soak  an  ounce  of  fish 
glue  in  cold  water.  Drain  off  the  water ; 
put  the  softened  glue  into  a  double  boiler 
and  melt  it,  but  do  not  bring  it  to  a  boil. 
Obtain  six  ounces  of  glycerin,  warm  it  and 
add  it  to  the  melted  glue.  Add  a  few 
drops  of  carbolic  acid.  Mix  thoroly  and 
pour  into  your  pan.    A  caramel  pan  is  best. 

Receipt  No.  2. — Add  3  ounces  of  water 
to  l1^  ounces  of  white  glue.  Heat  in  a 
double  boiler  until  glue  is  melted.  Then 
add  six  ounces  glycerin  and  pour  into  pan. 
If  too  hard,  add  glycerin.  If  too  soft, 
add  glue. 

Receipt  No.  3. — Dissolve  4  ounces  of 
gelatin  in  one  pint  of  cold  water;  then  add 
one  pint  of  glycerin.  Pour  into  a  double 
boiler,  and  when  it  comes  to  a  boil  pour 
into  your  pan. 

If  bubbles  appear  on  the  surface,  gently 
draw  an  edge  of  a  sheet  of  writing  paper 
over  the  surface  before  it  cools.  This  will 
remove  them. 

General  directions  for  use. — Use  noth- 
ing but  unglazed  paper,  which  can  be  pur- 
chased at  any  store  where  typewriter  paper 
is  sold.  In  ordering,  be  sure  to  state  that 
you  wish  to  use  it  for  hektography. 

Use  hektograph  ink  and  a  coarse  stub 
pen.  See  that  every  stroke  of  the  pen 
leaves  a  metallic  luster  when  dry,  else  the 
work  will  not  take. 

When  the  ink  is  dry,  lay  the  face  of  the 
sheet  which  you  have  written  or  drawn, 
down  on  the  hektograph ;  press  gently  over 
the  whole  surface  with  the  hand  or  soft 
cloth.  After  from  two  to  five  minutes  (ac- 
cording to  how  many  copies  are  desired) 
gently  peel  the  paper  off. 

From  the  impression  thus  made,  repro- 
duce all  the  copies  desired,  laying  one  sheet 
on  the  hektograph  at  a  time. 

Hektograph  ink  all  prepared  may  be 
bought,  or  your  druggist  will  put  it  up 
for  you.    The  following  is  the  receipt: 

Ink — Dissolve  one  dram  of  purple  aniline 
in  one  ounce  of  water. 

The  hektograph  solves  the  supplemen- 
tary reading  question.  Each  teacher,  or  any 
one  who  desires  a  number  of  copies  of  any 
text  or  drawing,  can  thus  prepare  as  many 
as  needed,  at  a  very  small  cost. 

Contributed  by  F.  H.  SWEET. 


June,  1917 


THE   ELECTRICAL  EXPERIMENTER 


125 


iUPAMGfFJtf 


Our  Amateur  Laboratory  Contest  is  open  to  all  readers,  whether  subscribers  or  not.  The  photos  are  judged  for  best  arrangement  and  efficiency 
of  the  apparatus.  To  increase  the  interest  of  this  department  we  make  it  a  rule  not  to  publish  photos  of  apparatus  unaccompanied  by  that  of  the  owner.  Dark 
photos  preferred  to  light  toned  ones.  We  pay  each  month  $3.00  prize  for  the  best  photo.  Make  your  description  brief  and  use  only  one  side  of  the  sheet. 
Address  the  Editor,  "With  the  Amateurs"  Dept. 


AMATEUR  RADIO  STATION 
CONTEST 
Monthly  Prize,  $3.00. 
This  month's  prize-winner. 

CEDRIC  E.  HART'S  EXCELLENT 
RADIO  OUTFIT. 

The  switch  panel  and  cabinet,  etc.,  shown 
in  the  accompanying  photo  have  all  been 


Cedric  E.  Hart's  Radio  Station  at  Salt  Lake 
City,  Utah,  with  Which  He  Obtained  Highly 
Efficient  Results. 

designed  and  built  by  myself,  and  with  this 
cabinet  I  have  no  difficulty  in  receiving  ail 
of  the  coast  stations  and  the 
amateurs  within  a  fair  distance 
of  here.  I  also  hear  Guam, 
Honolulu,  Alaska,  Panama,  etc., 
quite  regularly.  I  have  a  license 
and  my  call  is  6SL.  My  receiv- 
ing set  comprises  the  following: 
Navy  'phones,  Blitzen  tuner, 
Blitzen  variable,  Clapp-Eastbam 
tubular  fixt  condenser,  Turney 
variable  condenser,  and  an 
Audion  cabinet. 

My  transmitting  outfit  com- 
prises a  1K.W.  Thordarson 
transformer,  K.B.  preventer, 
commercial  key,  home-made  con- 
denser, Halcun  rotary  spark  gap, 
home-made  Telefunken  type  os- 
cillation transformer  and  a 
Blitzen  hot-wire  meter.  The 
switches  on  the  panel  control  the 
transformer,  power,  meter,  condenser  and 
inductance. 

This  set,  so  far,  has  proven  very  efficient 
and,  being  as  the  panel  has  not  been  com- 
pleted two  weeks  yet,  I  think  that  Evans- 
ton,  Wyo.,  is  a  pretty  good  distance  to 
transmit  for  the  short  time  I  bave  had  it. 
Here's  wishing  the  Experimenter  prosperi- 
ty in  its  chosen  path. 

CEDRIC  E.  HART. 

Salt  Lake  City,  Utah. 


H.  L.  SCOTT  TO  RENEW  HIS 
RADIO  ACTIVITIES. 

Just  recently  1  bought  a  copy  of  The 
Electrical  Experimenter,  the  January 
number,  and  on  reading  it  thru  it  has 
brought   back   pleasant    memories    of  the 

THE  MONTANA  WIRELESS 
STATION  OF  HOWARD  PASCOE. 

1  offer  herewith  a  photograph  of  "The 
Montana  Wireless  Station"  which  consists 
of  1  K.W.  Packard  transformer,  run  on 
(110  volts  A.C.)  and  a  stationary  spark 
gap. 

The  receiving  set  consists  of  a  loose 
coupler  designed  to  receive  up  to  2(),U00 
meters  and  a  loading  coil  for  4,000  meters. 

One  (type  D)  receiving  set  of  Marconi 
Wireless  Telegraph  Co.  make  which  has 
a  range  of  2,000  to  4,000  meters  or  more. 
One  pair  of  E.  I.  Co.  Republic  receivers, 
Standard  wave  meter,  silicon  and  Audion 
detectors  (Type  R  J  9). 

With  this  receiving  set  I  am  able  to  hear 
all  the  coast  stations  such  as  NPE,  XPC, 
and  the  amateurs  7ZC,  7JN  and  many 
others. 

I  have  a  little  sub-station  up  in  the  moun- 
tains, 6,355  feet  above  sea-level.  All  my 
wiring  is  run  in  conduit.  On  account  of 
the  small  space,  the  station  had  to  be  pho- 
tographed twice. 

I  read  The  Electrical  Experimenter. 
It  is  a  fine  magazine  for  the  "Wireless 
Bugs."  I  will  be  glad  to  correspond  or 
exchange  photos  of  my  station  with  other 
amateurs. 

HOWARD  PASCOE. 
Butte,  Montana  (1129  East  Galena) 


days  when  I  operated  my  station.  In  fact 
it  has  thrilled  me  so  much  that  I  am  go- 
ing to  renew  my  operations  with  the  old 
vigor.     (Not  until  after  the  War — Ed.) 

It  was  when  I  lived  at  158  Hamilton 
Street,  East  Providence,  R.I.,  in  1909  and 
1910,  that  I  had  my  best  outfit.    About  that 


Uncle  Sam  May  Find  the  Amateur  Radio  Station  of  Howard  Pascoe, 
at  Butte,  Montana,  of  Valuable  Assistance. 


Herbert  L.  Scott  and  His  Radio  Outfit,  Which 
Has  Done  Good  Work. 

time  I  believe  I  bought  a  detector  from  the 
Electro  Importing  Co. 

I  am  sending  you  a  photo  of  my  appa- 
ratus I  used  in  1910,  which  I  still  "have  in 
storage.  I  hope  you  will  find  space  in  the 
columns  of  your  magazine  to  reproduce 
this  photo.  For  sending  I  used  a  three 
inch  spark  coil,  run  by  six  V.  60  A.H. 
storage  batteries.  The  coil  may  be  seen  be- 
hind the  loose  coupler  on  the  table ;  over 
the  coil  on  the  board  is  a  plate  glass  con- 
denser; above  that  is  the  spark  gap  and 
then  the  helix  ;  to  the  right  is  an  anchor  gap. 

The  sending  key  may  be  seen  on 
the  extreme  right  of  the  table; 
the  contact  points  are  two  dimes. 

For  receiving  I  had  a  loose 
coupler  of  my  own  make,  a 
Murdock  tuning  coil  and  a  de- 
tector stand  in  which  I  used  sili- 
con, together  with  a  pair  of  3,000 
ohm  receivers,  potentiometer, 
fixt  condenser  and  Massie  sealed- 
point  electrolytic  detector  with 
double  pole  switch  to  throw  in 
either  system.  I  have  heard  Key 
West  with  this  station. 

HERBERT  L.  SCOTT. 
Blackstone,  Mass. 
(All  radio  men  should  read 
the  notice  in  "Radio  Dept."  and 
on  opposite  page — Ed.) 


ATTENTION!!! 
Has  your  station  photo  appeared  in 
"The  Electrical  Experimenter"? 
Why  not  purchase  the  electrotype 
and  have  some  "real"  stationery 
printed  with  your  station  picture 
on  it?  All  of  the  "regular  radio- 
bugs"  are  doing  it. 


"NO  MORE  'E.E.' " 

savs  the  newsdealer.  "All  sold  out !"  Did 
he  tell  YOU  so  last  time?  MORAL: 
Ask  him  to  order  a  copy  for  you  every 
month.  Costs  yon  nothing  to  do  so.  The 
tremendous  cost  of  paper  does  not  allow 
excess  printing,  so  we  furnish  dealers  only 
with  a  sufficient  amount  of  copies  to  supply 
their  regular  customers.  If  you  are  one, 
be  sure  to  tell  your  newsdealer  so,  and  give 
him  your  name  and  address,  so  he'll  notify 
you  by  postal  if  you  forget  to  call. 


126 


THE   ELECTRICAL  EXPERIMENTER 


June,  1917 


A  PROGRESSIVE  CHICAGO  RADIO 
EXPERIMENTER. 

My  sending  set  included  a  ]/^  K.W.  Blit- 
zen  transmitter  with  rotary  spark  gap,  op- 


One  of  the  Honor  Sets  Among  Chicago  Radio 
Amateurs  Was  that  of  Mr.  A.  R.  Gates.  Mr. 
Gates  Is  One  of  the  "Old  Guard  Boys,"  Hav- 
ing Been  a  Reader  of  "Modern  Electrics." 


erated  on  110  volts  A.C.  with  a  lamp  bank 
in  series  with  gap  motor.  Receiving  set  is 
result  of  reading  Modern  Electrics  and 
The  Electrical  Experimenter  for  over 
2l/2  years  and  is  home-made 

The  receiving  transformer  is  designed 
for  3,000  meters  with  two  variable  con- 
densers :  one  across  secondary  and  one 
shunted  across  'phones.  I  have  two  crys- 
tal detectors,  Ferron  and  galena,  operated 
with  a  three  point  switch.  Also  a  three 
element  vacuum  detector  for  long  range 
work.    The  two  D.P.D.T.  switches  on  each 


side  of  Audion  make  a  complete  switch- 
over from  crystal  to  Audion  apparatus. 
Also  to  amplify  weak  signals  there  is  a 
Muhi- Audi-Fone  and  2,000  'phones.  Sta- 
tion call  9NV. 
Chicago,  111.      ARTHUR  R.  GATES. 

AMATEUR  HEARS  SPY  RADIO 
CODE. 

Federal  authorities  hope  to  locate  the 
sender  of  ■  aerial  instructions  to  German 
spies  thru  the  disobedience  recently  of 
Malcolm  Ronberg,  who  has  (or  had)  an 
amateur  radio  plant  at  his  home,  6220  Uni- 
versity Avenue,  Chicago,  111. 

Ronberg  failed  to  obey  the  government 
mandate  to  dismantle  radio  stations.  He 
decided  to.  "listen  in"  before  complying. 

There  was  no  sound  for  several  minutes, 
then  a  peculiar  unfamiliar  call,  repeated 
over  and  over  again.  Then  there  followed 
an  even  stranger  grouping  of  letters,  a  code 
message. 

Ronberg  hurried  to  the  federal  building, 
con f est  he  had  been  listening  and  turned 
over  the  message.  It  was  sent  to  federal 
operators  at  Great  Lakes  station.  They, 
too,  failed  to  decipher  it.  But  the  fact  that 
Ronberg  received  it  in  his  small  amateur 
station  has  helped  the  searchers  to  trace  it. 

Ronberg  was  thanked,  instructed  to  dis- 
mantle his  plant  by  midnight  or  go  to  jail, 
and  a  squad  of  detectives  was  hurried  out 
under  orders  of  John  C.  Dillon,  chief  radio 
inspector  of  Chicago. 


Young  chickens  treated  with  electricity 
by  a  London  experimenter  grow  more  rap- 
idly than  those  raised  without  treatment. 


DE  FOREST  GIVES  $5,000  TO  AMER- 
ICAN DEFENSE  SOCIETY. 

Dr.  Lee  de  Forest,  the  wireless  inventor, 
has  offered  the  American  Defense  Society 
$5,000  as  the  nucleus  of  a  preparedness 
fund. 


A  RADIO  ECHO  FROM 
LARCHMONT  MANOR,  N.Y. 

Herewith  is  a  photo  of  my  radio  station. 
The  sending  set  is  composed  of  a  1  inch 
Bull-Dog  spark  coil,  a  sending  condenser, 
spark  gap,  key  and  transformer.  In  my 
receiving  set  there  are  three  loading  coils, 
two  fixt  condensers,  a  double  slide  loose- 


Clarence  de  Witt  Rogers,  Jr.,  a  Rising  Radio 
Student,  of  Larchmont  Manor,  N.  Y. 


coupler,  a  silicon  detector  and  a  de  Forest 
Audion.  I  have  two  1,500  ohm  'phones 
and  one  500  ohm  'phone. 

CLARENCE  de  WITT  ROGERS,  JR. 
Larchmont  Manor,  N.Y. 


Fort  Wayne  Radio  Association  of 
Indiana. 

The  Fort  Wayne  Radio  Association  of  Indiana 
began  the  New  Year  with  the  installation  of  the 
following  new  officers:  G.  Carter,  President;  R. 
Parvin.  Vice-president ;  D.  W.  May,  Secretary  and 
F.  Hall,  Treasurer. 

We  have  had  some  very  successful  meetings 
during  the  winter  months.  Our  best  and  most- 
lookt  for  speeches  are  given  by  Mr.  Carter,  who, 
besides  giving  good  talks,  has  formulas  worked 
out,  which  enables  us  to  see  if  we  are  getting 
the  most  out  of  our  transmitters. 

In  an  effort  to  lessen  interference,  we  have  a 
"QRM  Committee"  to  report  at  our  meetings  every 
two  weeks. 

Several  of  our  members  have  some  fine  long- 
distance work  to  their  credit.  They  are  9  P  C, 
9  W  F,  9  V  Y,  9  T  A,  9  K  G  and  9  U  H. 

We  will  be  glad  to  correspond  with  other  clubs 
so  as  to  exchange  ideas.  Address  communica- 
tions to  n.  W.  May  (9  TJ  H),  3021  Hoagland 
Avenue,  Fort  Wayne,  Ind. 


Alpena,  Mich.,  Has  a  Radio  Club. 

The  Alpena  Radio  Club  of  Alpena,  Mich.,  has 
been  formed  for  the  advancement  of  wireless 
telegraphy.  Meetings  are  held  every  Thursday 
evening  at  the  home  of  the  President,  516  .State 
Street.  The  officers  are:  President,  W.  A.  Pot- 
ter; Vice-president,  Hugo  Sorenson;  Secretary  and 
Treasurer.  P.  B.  Alger;  and  Consulting  Engineer, 
Mr.  J.  Mulavey.  All  communications  should  be 
addrest  to  the  Secretary,  P.  B.  Alger,  119  State 
Street,   Alpena,  Michigan. 


Allentown,  Pa.,  Radio  Men  Reorganize. 

The  Inter-City  Radio  Association  of  Allentown. 
Pa.,  organized  October  2S.  1915,  recently  re- 
organized under  a  new  name  to  be  known  hence- 
forth as  The  Y.  M.  C.  A.  Radio  Association  of 
Allentown. 

The  art  of  field  signaling  and  code  receiving 
are  now  being  taught  to  the  members  by  the  Chief 
I  )perator,  Harvey  Zinger.  The  following  are  the 
new  officers  of  the  Association:  D.  H.  Goodling, 
President;  Stanton  Nadig,  Vice-president;  Blair 
Cunningham,  Secretary;  Arthur  Breisch,  Treas- 
urer; Harvey  Zinzer,  Chief  Operator.  Correspond- 
ence with  similar  organizations  will  be  appreciated. 
Address  all  communications  to  D.  H.  Goodling, 
330  N.  Madison  Street.  Allentown,  Pa. 


Radio  Activities  in  Kansas  City,  Kansas. 

The  Kaw  Valley  Radio  Association  has  been 
formed  by  the  amateurs  of  this  city.  The  club  to 
date  has  seventeen  members  with  officers  as  fol- 
lows: Ralph  Rehm,  President;  Parker  Wiggin, 
Vice-president;  Harlow  Eppert,  Secretary;  Joe 
Harlan,  Treasurer. 


Amateur  News 

The  club  is  progressing  rapidly  and  is  certain 
to  obtain  more  members  in  the  near  future.  As 
yet  we  have  no  set  but  expect  to  obtain  one 
soon.  Regtdar  meetings  are  held  every  Thursday 
night  at  7:30.  All  communications  should  be 
sent  to  Harlow  Eppert,  841  State  Avenue,  Kansas 
City,  Kansas. 

Y.  M.  C.  A.  Wirtless  of  Salesburg,  HI., 
Sends  Basketball  Scores. 

The  wireless  club  of  the  Y.  M.  C.  A.  recently 
sent  out  the  scores  of  the  basketball  tournament. 
These  scores  were  sent  out  three  times  a  day,  at 
the  close  of  each  session,  12:00  o'clock  noon,  6:00 
o'clock  after  the  afternoon  session  and  at  10:00 
o'clock  after  the  night  session.    The  towns  which 


ALL  RADIO  AMATEURS 

ATTENTION!  f 

As  all  of  you  know  the  United  I 

f    States  is  now  in  a  state  of  war  with  1 

|    Germany,  and  as  true-blood  Amer-  [ 

1    ican    citizens,    we   are,    each   and  | 

1    every  one  of  us,  duty  bound  to  obey  1 

1    the  mandates  of  the  U.  S.  Govern-  1 

1    ment  officials.    The  Navy  Depart-  1 

1    ment  has  been  delegated  by  our  1 

I    President  to  close  all  amateur  or  | 

1    experimental    radio    stations,    no  1 

|    matter  whether  equipt  for  transmit-  j 

1    ting  or  receiving,  licensed  or  un-  | 

1    licensed,  and  therefore  we  shall  all  1 

|    have    to    abide    by    this    decree,  ] 

I    whether  we  like  it  or  not.  \ 

Therefore,    beginning    with    the  1 

I    next  issue  of  "THE  ELECTRI-  I 

j    CAL  EXPERIMENTER,"  we  will  1 

1    endeavor  to  feature  the  Electrical  1 

|    Laboratories  in  preference  to  any  | 

1    radio  stations  in  the  awarding  of  § 

1    the  monthly  prize  of  $3.00  in  this  | 

1    department.    Now  is  the  time  to  f 

1    get  busy  and  freshen  up  your  elec-  | 

1    trical   apparatus,   and   incidentally  1 

|    improve    your    understanding    of  f 

1    electrical  matters,  which  perhaps  | 

1    you  have  unwittingly  slighted  to  a  f 

|    large   degree   in  your   pursuit  of  1 

radio-telegraphy.  Let  her  go,  boys!  | 


were  connected  with  Thursday  night  were  Rock 
Island.  Peoria,  Springfield,  Cambridge,  Genesee 
and  Monmouth. 

Roy  S.  Landon  had  charge  of  this  work,  and 
under  his  supervision  the  boys  are  showing  an 
unusual  amount  of  interest.  Recently  the  boys 
received  and  sent  messages  to  the  University  of 
Iowa  station. 


Worcester  Tech.  Wireless  Club  is  Busy. 

The  Wireless  Club  of  Worcester  Tech.,  elected 
Warren  B.  Burgess,  '16,  of  Hyde  Park,  chief 
operator  in  charge  of  the  maintenance  of  the 
Tech.  station.  Twelve  new  members  were  voted 
in  and  plans  were  discust  for  a  series  of  talks 
to  be  given  by  Instructor  Carleton  D.  Haigis  of 
the  physics  department  on  the  theory  of  electric 
waves  and  other  subjects  interesting  to  wireless 
students.  The  president  was  empowered  to  ap- 
point a  committee  to  draw  up  plans  of  a  new  an- 
tenna to  be  erected  this  year. 

Hoboken,  N.  J.,  Wireless  Amateurs 
Secure  Clubrooms. 

The  Hudson  City  Radio  Association  has  secured 
rooms,  at  541  Central  Avenue,  Jersey  City,  where 
they  have  erected  a  large  aerial  and  a  sensitive 
receiving  outfit.  Code  practise  is  given  every 
night  to  those  who  desire  it. 

Election  of  permanent  officers  was  held  with 
the  following  results:  President,  Joseph  F.  Grece; 
Vice-president,  William  Biedenkapp:  Financial  Sec- 
retary. Frank  V.  Bremer;  Recording  Secretary, 
Clarence  Maves;  treasurer,  William  S.  Davidson. 

All  amateurs  in  Hudson  County  are  invited  to 
join  the  association.  Address  Clarence  Maves, 
Secretary,  90  Ferry  Street,  Jersey  City,  N.J.,  for 
an  application  blank. 

Waterbury  Radio  Club  of 
Waterbury,  Conn. 

The  Waterbury  Radio  Club  was  formally  organ- 
ized recently  by  15  local  young  men  who  are  in- 
terested in  wireless  telegraphy.  King  Sam,  the 
Chinese  young  man  who  is  probably  the  only  Chi- 
nese wireless  operator  in  New  England,  took  the 
initiative  in  banding  the  local  operators  together 
and  the  meeting  was  held  in  the  wireless  room 
at  the  Boys'  Club.  E.  C.  Glavin,  an  inventor  and 
a  pioneer  in  wireless  telegraphy  study,  attended 
the  meeting  and  was  named  as  honorary  chair- 
man. The  other  officers  are  Robert  W.  Culbert, 
Jr.,  Chairman;  Clinton  A.  Fitch  (operator  of  the 
Boys'  Club  wireless  set),  Secretary  and  Treasurer. 
The  membership  of  the  club  is  15  just  now  and 
it  is  planned  to  increase  it  to  25  later. 

The  publicity  secretary  for  the  club  is  King 
Sam.  He  stated  that  it  is  the  purpose  of  the 
organization  "to  further  advance  and  foster  the  art 
of  wireless  telegraphy  in  this  city." 


June,  1917 


THE   ELECTRICAL  EXPERIMENTER 


127 


EXPERIMENTAL  CHEMISTRY. 

{Continued  from  page  123) 
chloric  acid,  and  proceed  to  neutralize  them 
in  the  same  manner.  After  they  are  neu- 
tralized, and  after  applying  the  litmus  tests, 
place  in  a  clean  evaporating  dish  and 
evaporate  the  solution  to  dryness.  The 
equation  for  this  reaction  is  practically  the 
same  except  that  Potassium  is  substituted 

TABLE  OF  VALENCE. 

TABLE  NO.  1. 

Metals  and  Positives    Non-Metal  and  Nega- 
Radicals.  '  ti"-  Radicals. 


c 
o 

% 

Dyad. 

Triad. 

Tetrad. 

Monad. 

Dyad. 

Triad. 

Tetrad. 

H 

Mg 

As 

Pt 

F 

( ) 

N 

c 

Na 

Ca 

Sb 

Sn 

CI 

S 

P 

Si 

K 

Sr 

Bi 

Br 

so3 

B 

SiO« 

Ag 

Ba 

An 

I 

so4 

P03 

Hg 

Pb 

Fe 

NO. 

co3 

P04 

NH, 

Cu 

Cr 

N03 

c2o4 

AsOs 

CH:! 

Cd 

Al 

CIO 

CaHiOa 

As04 

C2H5 

Zn 

C103 

Co 

C10s 

Ni 

CIO, 

Hg 

Br03 

Sr 

10, 

Fe 

C8H302 

As  we  have  been  constantly  referring  to  metals, 
non-metals,  positive  radicals  and  negative  radicals, 
the  above  table  is  given  now,  before  the  study  of 
valence  is  taken  up,  so  that  readers  may  refer 
to  it  when  metallic  and  non-metallic  elements  are 
mentioned. 

for  the  Sodium,  as  : — 

KOH       +         HC1         =       KC1       +  H,0 
Potassium        Hydrochloric        Potassium  Water 
Hydroxid  Acid  Chlorid 

EXPERIMENT  NO.  56— 

Dilute  1  part  of  Sulfuric  acid  with  three 
or  four  parts  of  water,  and  place  in  a 
small-lipt  beaker  or  test  tube  as  in  the 
preceding  experiments,  and  neutralize. 
When  neutral,  filter,  and  place  in  an  evap- 
orating dish  and  evaporate  to  dryness. 
Either  one  of  the  following  equations  will 
take  place : — 

KOH  4-  H,S04  =  KHSO4  +  H30 
Potassium  Sulfuric  Potassium  Water 

Hydroxid  Acid  [Acid]  Sulfate 

or 


II 

Aluminum  Jl  - 
Ammonium  Mf' 
Antimony  Sb  » 
Barium  Be  • 
Bismuth  Bi  ' 
Cadmium 
Calcium 
Chromium 
Coba/f 


Hydrogen 
Iron 
Iron 
Lead 


Cd- 
Ca  - 
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Co  ' 
Cu  ■ 
H  • 
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Mercury 
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Potassium 
Silver 
Sodium 
Strontium 
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Wm  Slightly  soluble  in  water 
^'Jolublein  /voter  irtfh  very  /idle  acid. 


Table  of  Solubilities. 


H20 
Water 


2K0H      4-     H2SOi    =      K2S04  + 
Potassium  Sulfuric  Potassium 

Hydroxid  Acid  Sulfate 

The  reasons  that  two  equations  of  re- 
action which  may  take  place  is  more  fully 


explained  in  the  opening  of  this  article. 

If  desired  Sodium  Sulfate  [Na2SOi]  can 
be  prepared  in  the  same  manner  as  above. 

EXPERIMENT  NO.  57— 

Neutralize  Ammonium  Hydroxid 
|NHiOH]  by  the  preceding  methods,  and 
Nitric  Acid  [HNO*].  Make  the  tests  with 
the  red  and  blue  litmus  papers.  Evaporate 
as  before.  The  product  of  tin's  neutraliza- 
tion cannot  be  evaporated  to  complete  dry- 
ness, owing  to  the  fact  that  the  nitrat 
breaks  up. 

NHjOH     4-     HNO.,     =    NHjNO.i    4-  H20 
Ammonium       Nitric  acid       Ammonium  Water 
Hydroxid  Nitrat 

The  above  salts  which  were  prepared  by 
the  neutralization  of  acids  and  bases,  are 
soluble  salts. 

Salts  can  also  be  produced  by  the  action 
of  acids  on  metals ;  below  are  given  methods 
of  preparing  chlorids,  sulfats  and  nitrats. 

EXPERIMENT  NO.  58— 

Put  into  a  clean  test  tube  about  5  grams 
of  zinc  and  pour  over  it  about  10  cc.  of 
dilute  hydrochloric  acid.  It  will  be  re- 
membered that  this  experiment  was  per- 
formed in  a  previous  installment,  [Hydro- 
gen, Experimental;  January,  1917,  issue 
Electrical  Experimenter].  Apply  a  lighted 
splint  to  the  mouth  of  the  tube  and  notice 
any  familiar  action.  After  the  action  stops 
pour  the  liquid  upon  a  filter ;  then  evap- 
orate the  Filtrat  [the  solution  obtained 
after  filtering]  in  an  evaporating  dish,  and 
note  what  is  left. 

The  reaction  for  this  experiment  is : 

Zn    4-         2HC1  =    ZnCl2     4-  H2 

Zinc         Hydrochloric  Zinc  Hydrogen 

Acid  Chlorid 

The  gas  which  escapes  from  the  tube  is 
hydrogen,  and  by  applying  a  lighted  splint 
to  the  mouth  a  slight  explosion  should  be 
caused  to  occur.  The  product  obtained  in 
this  experiment  is  Zinc  Chlorid  [ZnCl2]. 

EXPERIMENT  NO.  59— 

Pour  about  10  cc.  of  dilute  Sulfuric  acid 
[H2SO4]  made  by  pouring  3  or  4  cc.  of 
strong  Sulfuric  acid  to  the 
water,  about  10  cc,  stirring  the 
liquid  constantly,  and  adding 
the  acid  in  small  quantities. 
[Never  add  the  water  to  the 
acid],  on  about  5  grams  of 
scrap  iron.  It  may  be  neces- 
sary to  heat  the  mixture  over 
the  Bunsen  burner  in  order  to 
produce  better  action.  After 
the  action  has  proceeded  for 
some  time  remove  from  the 
flame,  and  add  about  5  or  10  cc, 
[after  the  liquid  has  been  fil- 
tered]. After  the  water  has 
been  added  to  the  solution, 
place  in  an  evaporating  dish 
and  proceed  to  evaporate.  The 
reaction  for  this  experiment  is  : 

Fe  +  H2SOi  =  FeS04  +  H2 
Iron    Sulfuric    Ferrous  Hvdrogen 
Acid  Sulfate 

EXPERIMENT  NO.  60— 

Mix   5    cc    of   water  with 
about    5    cc.    of    Nitric  acid 
[HNOs].    Place  about  5  grams 
of  copper  scraps  in  a  test  tube 
and  add  the  10  cc.  of  Nitric 
acid,  prepared  as  above.   If  ac- 
tion does  not  take  place,  heat 
gently  over  a  Bunsen  burner. 
A    deep    green    solution  will 
form,  and  after  the  action  has 
stopt,  add  about  5  or  10  cc.  of 
water  and  slowly  evaporate,  as 
before.     If  the  evaporation  is 
carried  to  dryness  the  nitrat 
will  break  up  into  the  insoluble 
oxid,  which  will  manifest  a  black  color. 
To  avoid  this  action  the  liquid  need  not 
be    completely    evaporated,    but    it  may 
(Continued  on  page  154) 


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"MAN-HUNTING"   WITH  THE 
ELECTRIC  CALLING 
SYSTEM. 

One,  two.  three — pause — one,  two  =  32 
on  the  electric  calling  system  here  illus- 


Keyboard  of  Electric  "Man-Hunting" 
Machine.     It   Instantly   Summons  the 
Desired    Party   to   the    Nearest  Tele- 
phone. 


trated.  It  is  the  prince  of  man-hunters, 
serving  as  it  does  to  quickly  summon  any 
particular  individual  to  the  nearest  tele- 
phone, no  matter  in  what  part  of  the  plant 
or  shop  he  may  be  at  the  moment. 

The  Electric  Calling  System  is  primarily 
the  operating  instrument,  which  is  con- 
nected by  wiring  to  a  line  of  signals  con- 
sisting of  either  bells,  horns,  buzzers,  lights 
or  whatever  other  electrical  devices  it  is 
desired  to  use.  These  signals  are  dis- 
tributed thruout  the  establishment  in  such 
a  manner  that  every  foot  of  floor-space  is 
within  the  sound  radius  of  at  least  one 
signal. 

The  Calling  System  has  no  direct  con- 
nection with  the  telephone,  but  is  usually 
located,  for  convenience,  near  the  tele- 
phone central  station,  within  easy  reach 
of  the  operator's  hand.  The  operating  in- 
strument may,  however,  be  placed  any- 
where on  the  circuit. 

This  System  operates  on  a  voltage  of 
either  110  or  220,  A.  C.  or  D.  C.  It  is 
always  in  service  and  there  are  no  bat- 
teries to  cause 
trouble  or  to 
be  recharged. 
The  consump- 
tion of  cur- 
rent is  most 
economical. 

The  instru- 
ment is  made 
in  one  univer- 
s  a  1  model, 
which  has  a 
calling  capac- 
ity of  45  dif- 
ferent code 
numbers. 
There  is  no 
limit  to  the 
number  of 

signaling  devices  which  the  instrument  will 
control,  provided  sufficient  current  is  let 
into  the  line  to  operate  them. 

The  signals  are  controlled  by  eight  small 
levers  which  form  the  number  combinations. 


THE  ELECTRICAL  EXPERIMENTER 


June,  1917 


PATENTS 


An  Electric  Photometer 

(No.    1,218,946;    issued   to  Clayton 
Laing.) 

This  device  embodies  a  clever 
electrically  operated  photometer  for 
use  by  photographers  in  accurately 
calculating  the  proper  exposure  for 


any  strength  of  light  and  any  size 
lens  opening.  The  instrument  com- 
prises a  suitable  light  filter  and  co- 
operating shutters,  so  that  ordinary 
daylight  may  be  properly  compared 
with  a  standard  of  light  incorporated 
in  the  photometer.  The  light  stand- 
ard is  composed  of  a  small  electric 
bulb,  and  a  dry  battery  with  suitable 
switch.  When  equal  amounts  of 
light  penetrate  two  special  trans- 
lucent blocks,  they  appear  as  one 
block;  the  two  halves  of  the  block 
perfectly  balancing,  so  that  natural 
and  artificial  rays  are  of  equal  in- 
tensity. 


Antenna    for  Aeroplanes 
(No.    1,219,550;   issued    to  Walter 
Hahnemann. ) 
An    improvement    in    design  of 
wireless     antennae     for  aeroplanes 
comprising  a  bamboo  or  other  mast 


supporting  one  or  more  insulated 
flat-top_  aerials.  The  "ground"  ele- 
ment is  compensated  for  by  utiliz- 
ing the  metallic  aeroplane  structure; 
the  "aerial"  element  being  cared 
for  by  the  special  antenna  here 
shown.  The  inventor  has  paid  par- 
ticular attention  to  the  correct  de- 
sign of  aeroplane  antennae,  with 
respect  to  the  proper  maintenance 
of  the  stability  and  operating  char- 
acteristics of  the  aeroplane  itself 
and  claims  that  the  addition  of  his 
antenna  to  an  aeroplane  will  not 
cause  it  to  be  unbalanced  in  flight 
or  in  maneuvering. 


Pool  Table  Register 

(No.    1,220,420;    issued   to  William 
H.  Heffley.) 
An  interesting  and  practical  elec- 


tro-mechanical device  for  register- 
ing the  results  of  a  game  of  pool, 
etc.,  whereby  the  pool  ball  as  it 
falls  into  a  pocket,  closes  an  elec- 
trical contact.    This  causes  a  set  of 


magnets  to  operate  a  pawl  and 
ratchet  connecting  with  the  indi- 
cating needle  in  the  manner  shown, 
and  the  dial  may  be  marked  off  in 
any  suitable  style  and  colors.  The 
device  can  be  attached  to  any  pool 
table  without  altering  or  damaging 
it,  and  each  table  pocket  is  con- 
nected up  to  the  electrical  score- 
board. 


Electrolytic  Gas-Generator 

(No.   1,219,966;  issued  to  Isaac  H. 
Levin. ) 

Electrolytic  apparatus  designed  to 
produce  hydrogen  and  oxygen  gases 
by  subjecting  water  containing  a 
small  quantity  of  a  suitable  electro- 
lyte, such,  for  example,  as  potassium 
hydroxid,  sulfuric  acid,  etc.,  to  the 
action  of  an  electric  current,  which 


is  caused  to  flow  there-thru  from 
one  electrode  to  another,  both  elec- 
trodes being  submerged  in  water. 
The  solution  is  decomposed  in  the 
well-known  electrolytic  manner,  oxy- 
gen being  liberated  at  the  positive 
electrode  and  hydrogen  at  the  nega- 
tive electrode.  This  invention  re- 
lates particularly  to  an  electrolytic 
gas  generator  in  which  the  liquid 
acted  upon  is  contained  in  a  suitable 
receptacle,  having  two  sets  of  in- 
sulated electrodes  entirely  indepen- 
dent of  the  receptacle  proper. 


Radio    Arc  Transmitter 

(No.    1,220,072;    issued    to  Louis 
Cohen.) 

Hill 


loop  circuit  will  have  less  resistance 
than  the  antenna  circuit,  as  it  is 
closed  and  practically  all  of  the 
high  frequency  oscillations  produced 
will  flow  in  this  circuit.  When  the 
key  is  opened,  the  arc  oscillations 
will  charge  the  aerial  instead. 


Oscillating-Current  Generator 

(No.    1,221,034;    issued   to   Lee  de 
Forest.) 


An  improved  method  of  develop- 
ing powerful  high  frequency  oscilla- 
tions with  a  vacuum  tube  generator 
suitably  associated  with  one  or  more 
oscillatory  circuits.  The  inventor 
provides  an  evacuated  bulb  contain- 
ing mercury  electrodes,  which  pro- 
duce a  mercury  vapor  arc  within 
the  bulb.  Two  cold  electrodes  9, 
and  10,  are  utilized,  9  being  water 
cooled,  and  10  being  a  bent  hollow 
grid.  An  oscillating  circuit  is  as- 
sociated with  the  two  cold  electrodes 
9  and  10.  A  second  oscillatory 
circuit  is  provided  thru  inductance 
20,  and  capacity  21.  With  this  ar- 
rangement, the  oscillations  produced 
in  the  first  oscillatory  circuit  are 
increased  in  intensity  when  the 
period  of  the  second  oscillatory  cir- 
cuit is  made  equal  to  that  of  the 
first.  The  output  or  ''load"  circuit 
comprises  ground  24,  inductance  22 
and  aerial  23. 


Combination  Radio  Receiver  and 
Detector 

(No.    1,219,888;    issued    to  Frank 
Wallberg.) 


An  extremely  compact  "pocket" 
wireless  set,  comprising  a  tuning 
inductance,  crystal  detector  and  tele- 
phone receiver,  all  in  the  space  re- 
quired for  an  ordinary  watchcase 
telephone  receiver.  The  telephone 
receiver  and  detector  are  connected 
in  parallel,  and  this  unit  in  series 
with  the  aerial,  ground  and  tuning 
coil.  The  latter  is  adjustable  by 
means  of  a  switch;  the  tuning  coil 
is  wound  about  the  shell  of  the 
receiver,  and  the  detector  is  ex- 
tremely small,  being  placed  within 
the  receiver-magnet  chamber  as 
shown.  The  device  is  held  to  the 
ear  when  in  use,  and  the  switch 
turned  until  the  signals  come  in  the 
loudest.  . 


Electric  Land-Torpedo 

(No.   1,219,028;  issued  to  Abraham 
Must.) 


Instead  of  utilizing  the  "com- 
pensation wave"  method  of  radiating 
telegraphic  signals  by  means  of  a 
radio  arc  type  transmitter,  the  in- 
ventor has  developed  a  novel  scheme 
which  operates  as  follows:  With 
the  Poulsen  system,  energy  is  con- 
tinuously transmitted,  but  with  this 
arrangement  energy  is  radiated  only 
as  the  dots  and  dashes  are  sent  out. 
During  the  "space"  periods  no  cur- 
rent is  radiated  from  the  aerial,  the 
high  frequency  oscillations  being 
shunted  thru  a  variable  resistance 
key  8,  condenser  5-a  and  inductance 
2-a.  This  does  not  affect  the  opera- 
tion of  the  arc  and  no  appreciable 
sparking  occurs.  When  the  vari- 
able resistance  key  8,  is  closed,  the 

COPIES  OF  ANY  OF  THE  ABOVE  PATENTS  SUPPLIED  AT  10c.  EACH 


A  novel  invention  comprising  an 
electrically  driven  or  propelled  land- 
torpedo  possessing  several  unique 
features.  As  shown  in  the  illustra- 
tion, the  design  comprises  two  sec- 
tions; the  forward  compartment  con- 
taining the  charge  of  explosives  and 
detonating  means,  while  the  pivoted 
rear  unit  contains  the  electric  driv- 
ing motor  and  necessary  gears.  The 
land-torpedo  is  dispatched  from  a 
trench,  and  is  under  constant  con- 
trol of  a  soldier  in  the  trench.  It 
should  prove  useful  in  destroying 
barbed  wire,  and  other  impediments, 
as  when  it  has  reached  the  desired 
spot,  the  operator  simply  pushes  an 
electric  button  which  detonates  the 
explosive  charge  in  the  war-head  of 
the  torpedo,  thus  destroying  the 
obstruction.  The  torpedo  hauls  its 
electric  feed  wires  after  it,  as  it 
ambles  away  from  the  trench. 


Electric  Gas  Buoys  for  Submarine 
Warfare 

(No.  1,222,498;  issued  to  Joseph  A. 
Steinmetz.) 


Something  quite  new  in  the  realm 
of  war  machinery  and  comprising 
a  series  of  highly  charged  poisonous 
"gas  buoys,"  which  may  be  attached 
to  the  exterior  of  the  submarine, 
and  which  are  held  in  clamps,  elec- 
tro-magnetically  controlled  from  the 
interior  of  the  submarine.  The  lat- 
ter may  submerge  in  proximity  to  a 
hostile  war-ship  and  release  one  or 
more  of  the  gas  buoys.  These  float 
to  the  surface  and  even  tho  struck 
by  shell-fire,  they  will  proceed  to 
liberate  a  cloud  of  deadly  gas  fumes, 
which  are  supposed  to  eventually 
overcome  the  crew  of  the  war-ship. 
The  gas  buoys  may  be  released  and 
immediately  cut  free,  or  they  may 
be  maintained  in  position  by  a  cable 
as  shown,  so  that  they  will  not 
drift  away  before  their  task  is  fin- 
ished. 


Hood  for  Concealing  Telephone 

(No.  1,221,919;  issued  to  Lillian  A. 
Strasburger.) 


This  invention  provides  a  specially 
devised  concealing  hood  for  cover- 
ing the  telephone  instruments  in 
"My  Lady's  Boudoir,"  etc.  As 
shown  in  the  illustration,  the  device 
comprises  a  wire  frame-work  pro- 
vided with  a  spring  clip  and  a  doll's 
head.  The  attachment  is  suitably 
drapt  and  at  the  rear  it  is  pro- 
vided with  a  sliding  curtain.  To 
use  the  telephone,  it  is  but  neces- 
sary to  grasp  the  skirt  of  the  figure 
and  turn  the  whole  outfit  around 
180  degrees,  when  the  rear  curtain 
can  be  slid  sideways  and  the  re- 
ceiver moved  from  the  hook. 


June,  1917 


THE  ELECTRICAL  EXPERIMENTER 


129 


Phoney  Patents 


Under  this  heading  are  publisht  electrical  or  mechanical  ideas  which 
our  clever  inventors,  for  reasons  best  known  to  themselves,  have  as  yet 
not  patented.  We  furthermore  call  attention  to  our  celebrated  Phoney 
Patent  Offizz  for  the  relief  of  all  suffering  daffy  inventors  in  this  country 
as  well  as  for  the  entire  universe. 

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DOLLARS!  $3.00  FOR  THE  BEST  PATENT.  If  you  take  your  Phoney 
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you  haven*t  a  smell  of  the  Patent  yet.  After  they  have  allowed  the  Pat- 
ent, you  must  pay  another  $20.00  as  a  final  fee.  That's  $40.00  !  !  WE 
PAY  YOU  $3.00  and  grant  you  a  Phoney  Patent  in  the  bargain,  so  you 
save  $43.00  !  !  When  sending  in  your  Phoney  Patent  application, 
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Simple  sketches  and  a  short  description  will  help  our  staff  of  Phoney 
Patent   examiners   to   issue   a   Phoney    Patent   on   your   invention   in  a 

jiffy. 


No.  (I 


Phoney  Patent  Offizz 

S.  T.  Raphangr  of  Rushour,  D.  T. 

SELF    PROPELLED  TROLLEY 


Patent  Rattled 


To  Whomsever  II  Might  Concert: 

Be  it  knowed  to  all  unknown  and  all 
other  straphangers  at  large,  as  well  as  all 
those  confined  in  solitary  confinement 
thruout  the  world,  that  I  Salomon  Tad- 
dens  Raphangr  of  the  City  of  Rushour 
in  the  State  of  Deliriumtrcmens,  have  de- 
vised, designed,  designated  and  developed 
an  invention  of  the  most  far  reaching  con- 


all  the  power  and  lots  to  spare  besides, 
being  furnished  by  the  swaying  straphang- 
ers themselves.  The  excess  power  can  be 
used  to  light  the  car  and  charge  a  stor- 
age battery,  which  in  turn  may  drive  the 
car  when  traffic  is  light.  But  this  is  by 
no  means  all.  By  providing  all  seats  with 
a  spring  attachment,  the  seated  passengers 
will  bump  up  and  down  nicely,  and  I  found 


turn  drives  the  motors  5  under  the  car. 
The  motors  being  geared  to  the  axles  drive 
the  wheels  of  the  car.  The  car  wheels 
being  off  center,  as  observed,  will  give  the 
trolley  car  a  pitching  motion  like  a  ship 
in  a  swell.  This  greatly  aids  in  more  effec- 
tively swaying  and  bumping  the  passengers. 

The  seated  passengers  when  rising  up 
and  down   on  their  spring  seats  operate 


Straphangers  All  Over  the  Universe  As  Well  As  Trolley  Car  Magnates  Will  Rejoice  At  This  New  Invention.    Not  Only  Do  the  Sway- 
ing Passengers  Now  Propel  the  Car,  But  They  Experience  All  the  Variegated  Experiences  of  a  Sea  Trip  and  All  for  a  Nickel. 


sequences  to  a  long  suffering  traveling  pub- 
lic. 

It  is  a  well  known,  altho  deplorable  fact, 
that  the  modern  trolley  car  for  economic 
reasons  of  all  traction  companies  are  equipt 
with  rather  oval  as  well  as  "flat"  wheels. 
The  tracks  too,  are  of  the  scenic  railway 
type,  fashioned  after  the  camel's  back,  i.  e., 
hill  and  valley  with  15  hills  and  29  val- 
leys to  the  running  yard.  These  modern 
refinements  are  necessary  to  shake  up  and 
bump  the  cars  vigorously,  this  action  be- 
ing required  to  pack  the  passengers  tightly 
into  the  car  and  to  jingle  the  passengers' 
nickles,  so  the  latter  can  be  extracted  easier 
for  the  conductor's  rake-off. 

Having  in  mind  these  points  and  know- 
ing that  passengers  always  sway  to  and 
fro  in  all  our  trolleys  in  a  truly  alarming 
manner,  I  conceived  the  brilliant  idea  of 
utilizing  this  prodigious  energy,  now  going 
to  waste.  In  my  researches  I  quickly  found, 
that  if  you  start  the  car  on  an  incline, 
no  further  power  is  required  to  propel  it, 


this  to  be  far  more  pleasing  than  being 
bumped  up  and  down  on  hard  seats.  It 
is  also  very  healthy,  for  the  digestion  is 
greatly  improved,  especially  after  heavy 
meals.  It  will  ''settle"  the  heartiest  meal 
wonderfully.  If  the  public  comes  to  rea- 
lize this  it  will  patronize  my  new  self- 
propelling  trolley  in  a  manner  undreamt 
of  by  the  most  voracious  traction  com- 
pany shareholder.  No  power  house  nor 
trolley  wires  being  required,  the  company 
will  make  enormous  profits,  and  it  will 
be  able  to  issue  a  package  of  chewing  gum 
and  10  'trading  stamps  free  with  every 
nickel  ride. 

Referring  to  the  patent  drawing  we  find 
that  1  is  the  strap  on  which  the  strap- 
hanger navigates.  Every  time  he  sways  he 
exerts  a  pull  of  about  ISO  lbs.  on  the  strap, 
and  by  means  of  a  pawl  and  ratchet  ar- 
rangement mounted  on  a  common  shaft 
passing  thru  the  length  of  the  trolley,  the 
shaft  begins  to  rotate.  The  power  is  then 
conducted  by  belts  3  to  dynamo  which  in 


gears  4  and  the  resulting  power  is  also 
conveyed  to  the  belts  3,  this  furnishing 
additional  power. 
What  I  claim  is: 

1°  A  wireless  trolley,  operated  solely  by 
Straphangers. 

2°  A  self  propelled  fat  reducing  trolley 
stimulating  digestion  and  preventing  in- 
digestion. 

3°  A  trolley  car  giving  passengers  all 
the  experiences  of  a  sea  trip  for  a  nickel. 

In  consternation  whereof,  I  have  there- 
fore resolved  and  caused  to  he  appended 
and  imprest  hereunto  and  hereunder  the 
crest  of  my  family  shoe  tree  with  my  left 
uppermost  hind  foot  this  16th  day  after 
the  "ad'Vent  of  any  deceased  maiden  aunt's 
German  measles,  in  the  presence  of  three 
witnesses. 

S.  T.  RAPHANGR. 
Wittynesses:  By  his  Attorney, 

A.  W.  Gowan,       Thomas  W.  Benson, 
I.  M.  Indutch.       Phila.,  Pa. 
C.  U.  Titout 


130 


THE  ELECTRICAL  EXPERIMENTER 


June,  1917 


Lg3 


QUESTION  BO 


This  department  is  for  the  sole  benefit  of  all  electrical  experimenters.  Questions  will  be  answered  here  for  the  benefit  of  all,  but  only 
matter  of  sufficient  interest  will  be  publisht.    Rules  under  which  questions  will  be  answered: 

1.  Only  three  questions  can  be  submitted  to  be  answered. 

2.  Only  one  side  of  sheet  to  be  written  on;  matter  must  be  typewritten  or  else  written  in  ink;  no  penciled  matter  considered. 

3.  Sketches,  diagrams,  etc.,  must  be  on  separate  sheets.    Questions  addrest  to  this  department  cannot  be  answered  by  mail  free  of  charge. 

4.  If  a  quick  answer  is  desired  by  mail,  a  nominal  charge  of  25  cents  is  made  for  each  question.  If  the  question  entail  considerable  re- 
search work  or  intricate  calculations  a  special  rate  will  be  charged.  Correspondents  will  be  informed  as  to  the  fee  before  such  questions  are 
answered. 


RECORDING  VOLTMETER. 

(785.)  J.  Hassel,  Baltimore,  Aid.,  asks: 
Q.  1.  What  is  a  recording  voltmeter? 
A.  1.  A  recording  voltmeter  is  an  in- 
strument which  permanently  records  the 
potential  that  exists  between  points  in  an 
electric  circuit  during  any  definite  period. 
It  consists  of  nothing  more  than  an  ordi- 


Standard  Vo/tmeter\ 


Connections    for    Calibrating    a  Recording 
Voltmeter  With  the  Aid  of  a  Standard  Volt- 
meter and  Two  Rheostats. 


nary  voltmeter,  the  armature  or  moving 
element  of  which  carries  a  small  writing 
pen,  that  traces  a  curve  on  a  moving  strip 
of  paper.  The  variation  of  the  e.m.f.  in 
the  circuit  is  indicated  by  the  variation  of 
the  traced  curve.  The  strip  of  paper  which 
receives  the  record  is  moved  by  a  special 
clock  mechanism. 

Q.  2.  For  what  purpose  are  these  in- 
struments most  adapted? 

A.  2.  They  are  generally  employed  in 
power-houses,  where  it  is  required  to  know 
the  exact  voltage  conditions  of  the  line 
during  certain  periods  of  the  day. 

Q.  3.  Are  these  instruments  sufficiently 
accurate  to  warrant  their  use  in  laboratory 
work?    How  are  they  calibrated? 

A.  3.  No.  Most  of  them  require  a  large 
correction  factor.  Their  accuracy  depends 
upon  the  degree  of  voltage  variations,  as 
the  friction  between  the  pen  and  paper  is 
somewhat  great  when  the  moving  element 
is  caused  to  move  frequently. 

The  waring  diagram  herewith  gives  con- 
nections of  a  recording  voltmeter  for  cal- 
ibrating the  same  with  a  standard  volt- 
meter. 

IMPULSE  EXCITATION. 

(786.)  Paul  Magdale,  Hackensack,  N.  J., 
desires  to  know : 

Q.  1.  What  is  meant  by  impulse  excita- 
tion? 

A.  1.  Impulse  excitation  is  a  method  of 
exciting  the  antenna  by  means  of  an  oscil- 
latory circuit  which  is  highly  damped  and 
the  coupled  secondary  or  antenna  circuit 
receiving  an  impact  or  shock  from  the  pri- 
mary circuit,  and  permitting  this  secondary 
circuit  to  oscillate  with  as  little  damping 
as  possible.  The  primary  oscillatory  cir- 
cuit is  so  adjusted  or  tuned  that  a  single 
impulse  is  produced. 

Q.  2.  Is  the  quenched  spark  gap  system 
operated  on  the  impulse  excitation  prin- 
ciple ? 

A.  2.  Yes ;  but  it  is  not  an  ideal  im- 
!  pulse  excitation,  since  the  primary  of  the 
circuit  is  not  permitted  to  be  highly  damped. 
Furthermore,  the  oscillations  of  the  pri- 
mary are  periodically  cyclonic  and  not  im- 
pulsive or  semi-per.iod  oscillations,  as  that 


obtained  from  an  ideal  impulsive  excita- 
tion transmitter. 


RADIO  BOOKS. 

(787.)  Andrew  Colly,  Oyster  Bay,  L.  I., 
asks : 

plllllllillllllllllll 

TO  OUR  FRIENDS. 

B     Do  you  realize  that  not  one  day  B 

jj  passes  when  we  do  not  receive  from  jj 
M  150  to  250  or  more  letters  addrest  to 

f  the  "Question  Box''?    If  we  were  to  ji 

g  publish  all  the  questions  and  answers  B. 

B  we  would  require  a  monthly  magazine  B 

8  five  or  six  times  the  size  of  The  B 

j§  Electrical    Experimenter    with    no  = 

B  other  matter  but  questions  and  an-  B. 

B  swers!    Of  late  the  influx  of  letters  Bj 

M  has  become  so  heavy  that  several  of  g 

B  our  associates  have  been  forced  to  B 

HI  discontinue  important  editorial  work,  j§ 

B  in  order  to  answer  the  mail.  This  we  §1 

g|  are  certain  you  do  not  wish.  You  do  g 

B  not  want  your  magazine  to  lower  its  B 

g  present  high  standard.  You  want  the  8 

fjj  best,  the  very  best,  and  you  know  we  B 
fg  never'  have  failed  you  yet. 

g  Moreover  the  multitude  of  letters  B 
S  arc  wholly  unnecessary.  Most  of  the  S 
W=  questions  zvc  are  asked  every  day  B 
g  have  been  answered  before  in  the  B 
B  Question  Box.  Therefore  ere  you  B 
g  sit  dozen  to  write  to  us,  look  over  B 
B  your  back  numbers  and  nine  times  jj 
B  out  of  ten  you  will  find  the  answer,  B 

jjj  We  strive  hard  to  publish  only  B 
g  such  matter  as  has  not  appeared  be-  m 
B  fore  in  our  columns,  and  for  that  B 
B  reason  only  a  small  fraction  of  que-  B 
jg  ries  of  those  received  by  us  are  ac-  B 
B  tually  publisht. 

S  Kindly  note,  therefore,  that  in  the  B 
jj  future  zve  cannot,  in  your  own  in-  B 
B_  tercst,  answer  questions  by  mail,  free  m 
B  of  charge.  B 

jj  For  questions  requiring  immedi-  B 
g  ate  answer  our  fee  is  25c.  for  the  =. 
B  first  ordinary  question  and  25c.  for  M 
H  each  additional  question.  We  will  j| 
Ij  gladly  advise  fee  for  special  ques-  \ 
B  tions  entailing  considerable  calcu-  B 
j§  lations  or  research.  Stamped1*  and  B 
B  addrest  envelope  should  be  enclosed  B 
3  with  the  queries  and,  moreover,  any  B 
B  sketches  accompanying  them  should  B 
jj  be  made  on  separate  sheets.  And  B 
B  please  be  brief.  B 
THE  EDITORS.  1 
=  1     ^      \ii  :  1  '  1  ,  I'  -J'.'  |i'  'Z^,,- 

Q.  1.  Where  can  I  buy  wireless  books 
describing  in  detail  the  complete  theory  of 
radio  engineering,  and  also  a  text-book 
giving  complete  data  as  to  the  design  and 
operation  of  radio  apparatus? 

A.  1.  We  would  recommend  the  follow- 
ing books,  which  we  believe  will  give  you 
all   the  desired   information :     By   J.  A. 


Fleming,  "The  Principles  of  Electric  Wave 
Telegraphy,"  $10.00;  by  J.  Zenneck,  "Wire- 
less Telegraphy,"  $4.00;  Eccles'  "Wireless 
Telegraphy  and  Telephony,"  $3.50.  We  w.ill 
send  any  of  these  books  on  receipt  of 
price. 

Q.  2.  Are  all  the  Radio  Amateurs  of 
this  country  to  remove  their  aerials  and 
apparatus  in  this  present  crisis? 

A.  2.  Orders  have  already  been  given 
to  instruct  all  Amateurs  thruout  the  coun- 
try to  remove  their  aerials.  The  instru- 
ments were  not  asked  to  be  removed  or 
confiscated  by  the  authorities  up  to  the 
present  time.   

WIRING  DIAGRAM. 

(789.)  Peter  Hancock,  Toledo,  O., 
wants : 

Q.  1.  A  wiring  diagram  of  a  short  wave 
regenerative  Audion  receiving  outfit. 

A.  1.  The  appended  diagram  gives  the 
proper  connections. 

Q.  2.  How  can  I  eliminate  the  noises 
produced  in  the  receiver  when  the  Audion 
is  in  operation?  This  effect  is  even  ob- 
tained when  the  receiving  instruments  are 
disconnected  from  both  the  aerial  and 
ground. 

A.  2.  The  noise  which  you  are  experi- 
encing is  due  to  a  constant  electrical  charge 
on  the  grid  of  the  Audion,  which  causes 
the  grid  condenser  to  charge  and  discharge 
unperiodically ;  consequently  affecting  the 
receivers.  This  trouble  might  be  eliminated 
to  a  certain  degree  by  shunting  a  high  re- 
sistance "leak"  path  across  the  grid  con- 
denser. It  must  be  a  non-inductive  leak 
and  can  be  made  very  readily  by  marking 
upon  a  sheet  of  paper  a  pencil  mark  and 
connecting  the  ends  of  this  line  across  the 
condenser.  A  little  patience  in  making  the 
proper  thickness  of  line  will  be  required 
before  proper  results  can  be  obtained. 


Hook-up   for  a    Short    Wave  Regenerative 
Audion  Radio  Receiver. 


WAVE  LENGTH  OF  ANTENNA. 

(790-A)  Thomas  Lowman,  East  Pitts- 
burgh, Pa.,  inquires  : 

Q.  1.  Can  you  give  me  the  wave  length 
of  an  antenna  which  consists  of  four  wires 
60  feet  high,  100  feet  long,  and  the  wires 
separated  2  feet? 

A.  1.  The  wave  length  of  this  antenna 
is  300  meters. 

Q.  2.  Suppose  I  desire  to  use  this  an- 
tenna with  a  transmitting  station,  which 
will  comprise  a  500  watt  60  cycle  trans- 
(Continued  on  page  137) 


June,  1917 


THE  ELECTRICAL  EXPERIMENTER 


131 


Who  Gets  $200,000,000 

Tire  Profits? 

An  amazing  condition  revealed  in  the  tire  business.  Terrible 
waste  shown  by  methods  of  selling  automobile  tires.  How  one 
tire  man  plans  to  cut  the  cost  of  tires  to  the  consumer  revealed 

Tire  Chain  Stores  Offer  Solution  of  Problem 

By  M.  E.  PHILLIPS,  "Staff  Correspondent"  (Home  Magazine) 


NOTE. — The  following  article,  written  by  our  staff  representa- 
tive, outlines  plans  for  a  giant  chain  of  tire  service  stations  and 
stores  which  it  is  predicted  will  greatly  lower  automobile  upkeep 
costs.  A  unique  co-operative  plan  which  has  been  tested  out 
and  found  successful.  Output  of  splendid  factory  already  secured, 
more  to  follow.    The  success  of  other  chain  stores  and  the  tre- 


mendous growth  of  the  automobile  industry — consequently  of 
the  tire  business — makes  this  one  of  the  most  attractive  and  in- 
teresting enterprises.  We  have  made  every  effort  to  verify  the 
statements  made  here  and  to  the  best  of  our  knowledge  the 
statements  are  accurate  and  the  estimates  conservative. —  (Pub- 
lisher Home  Magazine.) 


Who  gets  the  $200,000,000.00  A  YEAR  TIRE 
PROFITS? 

Do  you  know  that  the  cost  of  producing  a  tire 
is  possibly  ONE-THIRD  of  the  price  you  have 
to  pay?  That  a  small  tire  you  pay  $15.00  for 
costs  about  $5.00  to  manufacture?  That  the 
tire  costing  about  $20.00  to  build  lias  to  retail 
for  about  $60.00? 

Do  you  know  that  the  tire  manufacturer  is 
satisfied  to  sell  his  tires  for  very  little  over 
the  cost,  and  at  only  a  fraction  of  the  retail 
price? 

Where  does  the  balance  go? 
Who  then  gets  this  enormous  "cut  in"  on 
the  tires  vou  buv? 

DO  YOU?    Of  course  not. 
Who,  then? 

Well,  the  JOBBER  gets  a  BIG  slice. 
The    WHOLESALER   gets    another  BIG 
slice 

The  RETAILER  gets  HIS  SHARE. 

The  rest  goes  into  advertising,  dealer's  helps, 
adjustments,  etc. 

Meanwhile  YOU,  Mr.  Tire  Buyer,  pay  the 
100  per  cent  price  and  worry  about  the  high 
price  of  upkeep  of  your  motor  car. 

WILL  CUT  TIRE  COSTS 

A  clever  tire  man,  a  man  with  intimate 
knowledge  of  the  tire  industry,  a  man  with 
breadth  of  vision  and  economic  principles,  has 
seen  this  enormous  WASTAGE  in  the  tire 
business  and  has  evolved  a  PLAN  that  will 
revolutionize  the  tire  selling  business. 

He  argues  that  TIRES  COST  THE  CONSUMER  TOO  MUCH. 

He  says  there  is  no  reason  on  earth  why  the  tire  buyer  should 
have  to  pay  this  enormous  burden  of  profits  and  selling  costs. 
If  tires  can  be  made  for  ONE-THIRD  of  the  actual  retail  prices 
they  can  be  sold  FOR  LESS  than  prices  now  charged  for  them  and 
still  pay  legitimate  profits.  LARGE  PROFITS,  because  of  the 
volume  of  business  a  company  offering  such  savings  is  bound  to 
achieve. 

This  far-sighted  man  is  a  PRACTICAL  TIRE  MAN.  As  a 
manufacturer  he  has  MADE  GOOD.  He  is  a  PRACTICAL 
BUSINESS  MAN,  with  all  a  practical  man's  dislike  for  waste. 
He  has  proved  his  genius  for  organization  and  big  things. 

This  man  is  Mr.  J.  G.  Feist,  President  of  the  National  Rubber 
Company  of  New  York. 

PLANS  CHAIN  OF  STORES 

_  Mr.  Feist's  plan  is  to  establish  a  chain  of  tire  service  and  store  sta- 
tions from  Maine  to  California,  and  Canada  to  the  Gulf  of  Mexico. 

The  National  Rubber  Company  of  New  York  has  been  organized 
with  strong  men  behind  it  and  it  has  already  secured  the  output 
of  one  entire  factory  as  the  nucleus  of  this  chain  store  plan. 
More  factories  will  be  added  as  the  chain  extends  and  the  need 
of  more  tires  becomes  evident.  The  first  factory  whose  product 
has  been  acquired  is  the  National  Rubber  Company  of  Pottstown, 


The  Famous  Philadelphia  Experimental  Tire  Service  Store  that  Proved  to  President  Feist 
of  the  National  Rubber  Company  the  Practical  Possibilities  of  Tire  Chain  Stores,  Located 
at  the  Corner  of  North  and  Broad  Streets. 


Pa.,  manufacturers  of  the  famous  National  Speedway  Tires  and 
National  Red  Tubes. 

The  NATIONAL  SPEEDWAY  REDWALL  TIRES  are  so 
GOOD  that  they  are  sold  under  the  strongest  GUARANTEE 
to  be  had. 

The  company  agrees  to  replace  FREE  any  tire  that  does  not 
outlast  and  outwear  any  tire  of  any  make  or  price  of  the  same 
size  tested  under  the  same  conditions. 

This  company  now  has  a  production  of  1,000  tires  and  tubes  a 
day  and  is  being  enlarged  to  a  much  greater  capacity.  When 
the  distribution  exceeds  the  capacity  of  this  plant,  new  plants  will 
be  started  or  bought  in  different  sections  of  the  country,  or  their 
outputs  contracted  for  in  order  to  bring  up  the  production  to  the 
necessarv  number  of  tires. 

Mr.  Feist  proposes  to  sell  tires  at  a  MUCH  LOWER  PRICE 
than  is  now  being  charged  for  good  tires  elsewhere. 

He  plans  to  give  SUPERIOR  SERVICE  to  tire  buyers. 

He  will  give  them  a  BETTER  TIRE.  He  anticipates  that  in 
doing  this  his  company  will  prove  the  greatest  profit  maker  in 
the  country. 

EXPERIMENTAL  PLANT  A  SUCCESS 

Mr.  Feist  is  not  building  his  company's  future  on  imagination 
or  theory.  Before  maturing  his  plans  he  opened  in  Philadelphia 


132 


THE   ELECTRICAL  EXPERIMENTER 


June,  1917 


Boston  Service  Store  of  National  Rubber  Company,  Located  at  557 
Columbus  Avenue. 

a  station  such  as  he  proposes  to  establish  elsewhere. 

This  is  what  his  Philadelphia  service  station  and  store  does : 

It  sells  tires  below  the  average  price  of  high-class  tires  of  equal 

size  and  quality. 
It  delivers  tires  PUT  ON  YOUR  CAR. 

You  phone  in  that  you  need  a  34x4  tire  and  give  your  address. 
A  mechanic  picks  up  the  required  tire,  puts  it  in  the  carrier  of  a 
motorcycle  and  speeds  off  to  your  address.  On  arrival  he  takes 
off  your  old  tire  and  puts  on  the  new  one.    No  trouble,  no  mess. 

If  you  want  your  old  tire  repaired  he  takes  it  back  with  him  and 
it  is  delivered  as  soon  as  repairs  are  made. 

You  have  saved  time,  labor,  worry  and  money. 

The  success  of  this  first  service  station  PROVES  what  REA- 
SONABLE PRICES,  HIGH  QUALITY  GOODS,  EFFICIENT 
SERVICE  will  accomplish.  Profits  are  large  because  of  volume. 
The  Philadelphia  service  station  already  has  11,000  CUSTOM- 
ERS.   (Not  tire  sales,  but  CUSTOMERS.) 

With  this  established  PROOF  of  the  value  of  this  new  departure 
service,  Mr.  Feist  has  organized  a  company  to  establish  National 
Rubber  Company  SERVICE  STATIONS  and  stores  all  over 
the  country.  His  plan  provides  for  opening  500  stores  the  first 
year,  if  possible,  and  more  stores  year  by  year  as  the  company 
grows.  / 

OFFERS  GREAT  OPPORTUNITIES 

The  OPPORTUNITIES  offered  by  this  chain  of  tire  service 
stores  are  self-evident. 

CHAIN  STORES  of  all  kinds  have  been  enormously  success- 
ful. They  have  built  up  some  of  the  greatest  fortunes  in  the 
country.  They  have  made  original  investors  enormously  rich. 
And  this  in  spite  of  the  fact  that  most  chain  stores  have  dealt 
only  in  articles  selling  for  a  very  small  sum.  HOW  MUCH 
GREATER  should  be  the  profits  of  a  chain  of  stores  selling  a 
product  whose  every  SINGLE  SALE  equals  the  sale  of  HUN- 
DREDS of  the  articles  sold  in  most  chain  stores?  ■  ■.■ 

The  UNITED  CIGAR  STORES,  selling  cigars,  cigarettes  and 
tobacco,  average  LESS  THAN  20  CENTS  PER  SALE.  The 
National  Rubber  Company  averages  MORE  THAN  $20  PER 
SALE,  with  proportionate  profits. 

THE  WOOLWORTH  STORES  sell  5  and  10  cent  articles. 
Yet  they  have  made  many  millions  and  the  highest  office'  building 
in  the  world  was  built  out  of  these  nickels  and  dimes. 

The  REGAL  SHOE  COMPANY  with  its  chain  of  hundreds  of 
shoe  stores,  has  made  its  owners  rich.  So  have  the  Walk-Over 
Shoe  Stores,  the  W.  L.  Douglas  Shoe  Stores.    All  chain  stores. 

The  TRULY  WARNER  Hat  Store  chain  has  accumulated 
wealth  for  its  owners. 

The  Great  Atlantic  and  Pacific  Tea  Stores,  the  Jewel  Tea 
Stores,  the  Acme  Tea  Stores,  all  chain  stores,  have  made  millions. 

The  several  chains  of  drug  stores,  of  grocery  stores,  of  cheap 
restaurants,  have  all  made  fortunes. 

The  reasons  for  this  uniform  success  are  numerous. 

In  the  first  place,  operating  a  "chain  of  stores"  of  any  kind 
reduces  the  cost  operation — what  is  known  as  OVERHEAD  EX- 
PENSE— to  the  minimum. 

Secondly,  the  purchasing  power  of  the  buyer  who  buys  for 
hundreds  of  stores  is  so  enormous  that  he  can  pretty  nearly  make 
his  own  price.  He  gets  ROCK  BOTTOM  costs  on  everything. 
Woolworth  can  sell  for  5  or  10  cents  articles  that  often  retail  at 
from  25  to  50  cents  because  he  buys  outright  entire  factory  pro- 
ductions.   The  manufacturer  who  sells  his  whole  output  to  one 


man  for  cash,  eliminates  all  selling  expense,  salesmen,  advertising, 
collections,  etc.,  and  can  sell  for  a  quick  turnover,  and  will  yet 
make  more  profit  in  the  end.  That's  how  the  chain  store  buyer 
can  buy  at  such  a  low  figure  that  he  can  sell  goods  that  retail 
generally  for  25  cents  for  5  and  10  cents. 

Then,  the  chain  store  man  nearly  always  buys  FOR  CASH. 
That  means  he  takes  advantage  of  every  cash  discount  and  by 
paying  cash  he  enables  his  manufacturer  to  buy  for  cash  and  get 
a  similar  benefit.  So  it  becomes  an  endless  chain  of  savings  which 
benefits  the  ultimate  consumer  of  the  product. 

ECONOMY  OF  CASH  BUYING 

The  chain  store  man  uses  his  cash  to  buy  everything.  He  buys 
everything  the  same  way.  He  buys  his  fixtures,  his  delivery 
wagons — if  he  uses  them — his  every  necessity  at  the  lowest  bulk 
price,  and  bulk  with  the  chain  store  man  means  tremendous  bulk. 

If  these  chain  stores,  selling  articles  that  retail  for  such  a  small 
price,  can  earn  such  fabulous  dividends,  what  will  a  chain  of  tire 
service  stores  earn  with  the  big  sales  it  will  make ;  sales  averaging 
$20  apiece? 

It  doesn't  take  a  prophet  to  look  into  the  future  and  see  the 
magnificent  accumulations  of  dividends  that  should  accrue  from 
such  an  enterprise. 

It  isn't  hard  to  foresee  what  the  earnings  of  such  a  chain  of 
stores  can  pay  in  say  ten  years  from  today.  By  that  time  the 
chain  should  extend  to  every  city  of  any  importance  in  the  coun- 
try. This  may  mean  thousands  of  such  stores,  because  there  are 
in  the  United  States  1,442  towns  of  5,000  or  more  inhabitants 
and  over  100  cities  having  a  population  of  55,000  or  over.  The 
small  towns,  say  the  towns  under  10,000,  would  require  only 
one  such  service  station,  while  the  larger  towns  would  require 
a  number  of  them. 

THOUSANDS  OF  CHAIN  STORES 

To  give  you  an  idea  of  how  many  stores  some  of  the  big  chains 
have,  it  is  enough  to  mention  the  Great  Atlantic  and  Pacific  Tea 
Company,  with  over  1,500  retail  stores ;  the  United  Cigar  Stores, 
with  over  1,000  retail  stores ;  the,  Woolworth  Company,  with  over 
1,000  stores,  etc. 

The  tremendous  growth  of  the  automobile  industry — a  growth 
that  is  gathering  size  and  importance  every  day — makes  this  pro- 
jected chain  of  tire  service  stores  all  the  more  important. 

At  the  beginning  of  1917  there  were  approximately  THREE 
MILLION  autos  in  use  in  the  United  States.  According  to  last 
United  States  census,  there  were  in  1910  (date  of  last  census) 
91,972,266  inhabitants  in  the  U.  S.  It  is  calculated  that  there  are 
now  at  least  120,000,000  people  in  the  U.  S.  At  this  rate,  there 
is  one  auto,  in  the  U.  S.  for  every  40  people.  In  many  of  the 
states,  the  ratio  is  higher  than  one  for  every  16  people.  This 
means  that  THERE  IS  A  TREMENDOUS  POSSIBILITY  FOR 
MORE  MACHINES. 

According  to  the  best  informed  automobile  authorities,  it  is 
calculated  that  there  will  be  added  at  least  1,000,000  auto  users 
during  the  year  1917,  bringing  up  the  total  close  on  to  FOUR 
MILLION  AUTOS  in  actual  use  in  the  U.  S.  With  such  an 
enormous  distribution  of  cars,  and  all  the  automobile  factories 
of  any  account  way  behind  in  deliveries,  an  enormous  supply 
of  tires  will  be  required  to  keep  these  autos  running. 

24,000,000  TIRES  NEEDED 

Very  moderate  estimates  place  the  number  of  tires  required 
on  each  car  at  EIGHT  PER  YEAR.  Each  auto  MUST  HAVE 
FIVE  TIRES,  four  on  the  wheels  and  one  spare  tire.  It  is  an 
ultra  conservative  estimate,  therefore,  that  places  the  required 
number  of  tires  to  meet  the  needs  of  1917  at  SIX  PER  CAR. 
At  this  rate  4,000,000  automobiles  will  require  24,000,000  tires. 
This  is  truly  AN  AMAZING  FIGURE  for  an  industry  that  is 
only  a  little  over  a  dozen  years  old. 

The  distribution  of  these  cars  is  centered  at  present  in  certain 
sections.  When  the  other  sections  have  awakened  to  the  advan- 
tages and  uses  of  the  automobile  and  its  economj-  for  travel  and 
commercial  purposes,  it  is  more  than  likely  that  the  distribution 
will  be  much  more  even. 

It  has  been  estimated  by  statisticians  that  there  are  OVER 
TEN  MILLION  men  in  the  U.  S.  who  should  be,  and  probably 


Chicago  Store  of  National  Rubber  Company,  the  Third  in  the  Chain. 


June,  1917 


THE   ELECTRICAL  EXPERIMENTER 


133 


soon  will  be,  auto  owners.  These  are  men  who,  because  of  their 
business,  their  financial  condition  and  their  position,  should  be- 
come automobile  owners. 

There  are  upwards  of  seven  million  farmers  in  the  U.  S.,  and 
of  these  a  large  percentage  will  probably  become  owners  of  auto- 
mobiles. Just  now  only  about  7  per  cent  of  the  prosperous  farmers 
own  automobiles.  The  farmer  is  today  the  RICH  MAN  of  the 
U.  S.  He  has  been  getting  the  biggest  prices  ever  paid  for  crops, 
he  has  by  scientific  farming  increased  the  yield  of  his  acres, 
and  he  has  been  fortunate  in  getting  big  crops  when  the  price 
was  highest. 

For  these  reasons,  THE  FARMER  IS  USUALLY  PROS- 
PEROUS and  lie  is  putting  some  of  his  riches  into  the  comforts 
and  conveniences  of  an  automobile. 

With  such  prospects,  with  such  a  tremendous  field  to  concpier, 
with  the  SUCCESS  that  has  attended  the  FIRST  UNIT  of  the 
National  Rubber  Company  chain  of  service  stores,  it  is  not  hard 
to  visualize  the  ENORMOUS  POSSIBLE  PROFITS  from  this 
enterprise. 


Officers  and  Officials  of  the  National  Rubber  Company  of  New  York.  These  Men 
Have  Made  the  Making  and  Selling  of  Tires  Their  Life  Work,  Both  as  Manufacturers 
and  Branch  Managers.  They  are  Pioneers  in  the  Tire  Business;  They  Have  Watched 
the  Tire  Business  Grow  from  the  Experimental  Stage.  Today  They  are  Large  Fac- 
tors in  the  Manufacturing  of  the  Best  Tire  that  Money  Can  Make.  Mr.  Walsh,  Who 
Is  Superintendent  of  the  Plant,  Has  Been  for  23  Years  in  Active  Charge  of  the 
Making  of  the  Best  Known  Tire  in  America.  Mr.  Sperry  Was  With  the  Deere  Plow 
Co.  as  Agency  Organizer.  Mr.  Dougherty  Has  Been  a  Tire  Representative  for  Years, 
Formerly  With  the  Lee  Tire  Co.  H.  A.  Lamoree  Has  Also  Been  a  Branch  Tire  Store 
Manager  and  General  Tire  Salesman  With  Several  of  the  Big  Companies. 

HOW  PROFITS  PILE  UP 

Even  a  casual  consideration  of  the  subject  makes  the  figures 
run  into  such  amazing  columns  of  profits  that  the  very  thought 
is  staggering. 

The  great  earnings  of  chain ,  stores  of  all  kinds  has  been  in 
the  aggregate. 

When  you  take  1,000  stores  and  pile  their  profits  in  one  great 
heap,  you  have  a  formidable  aggregate — an  aggregate  which 
doesn't  have  to  be  very  large  in  the  individual  case  to  make  up 
this  magnificent  total. 

Let  us  take  into  consideration  one  unit  and  then  see  how  it 
works  out. 

Firstly,  we  must  remember  that  these  service  stores  are  oper- 
ated at  a  minimum  of  expense.  Being  administered  from  the 
central  office,  whose  costs  of  operation  are  spread  over  the  whole 
chain,  the  local  stores  require  only  inexpensive  help.  The  man 
who  operates  a  store  of  his  own  expects  to  make  A  GOOD 
LIVING  out  of  it  for  himself  AND  A  GOOD  PROFIT  besides; 
he  has  to  pay  for  everything  on  the  high  price  of  individual 
He  has  to  have  efficient  help,  has  to  advertise  and, 
he  has  fixed  charges   for  rent,  light,  taxes,  insur- 


purchases. 
of  course, 
ance,  etc. 


CHAIN  STORE  SAVINGS 

The  chain  store  hires  only  the  necessary  help,  it  eliminates 
the  owner's  living  and  profits.    It  buys  in  enormous  quantities 


at  prices  that  make  the  prices  the  individual  store  owner  pays 
seem  preposterous ;  it  pays  the  minimum  for  taxes,  for  insur- 
ance and  the  advertising  expense  of  operating  is  carried  in  bulk 
by  the  parent  company,  and  this  is  divided  pro  rata  so  that  each 
individual  store  pays  only  a  small  sum  as  its  share  of  the  adver- 
tising expense. 

Tires  are  bought  at  actual  contract  price  from  the  manufacturer 
and  so  charged  agains  the  store,  much  cheaper  than  the  average 
tire  store  man  can  buy  them. 

We  then  have  EXPENSES  PARED  DOWN  TO  THE  BONE, 
probably  HALF  WHAT  THEY  WOULD  BE  UNDER  ORDI- 
NARY CONDITIONS.  And  we  have  the  most  attractive  kind 
of  a  proposition  to  offer  to  the  tire  buvej — THE  BEST  TIRE 
ON  THE  MARKET  AT  MUCH  LESS  than  he  would  have  to 
pay  elsewhere;  A  SERVICE  NO  OTHER  TIRE  CONCERN 
GIVES  or  can  give,  GUARANTEED  SATISFACTION  backed 
up  by  a  company  operating  a  nation-wide  chain  of  stores. 

With  so  much  to  offer  and  with  such  splendid  profit-making 
advantages  it  is  not  hard  to  look  into  the  future  and  see  every 
store  paying  a  big  profit  and  the  company  earn- 
ing dazzling  dividends. 

What  may  one  store  earn,  you  may  ask? 
Let  us  do  a  little  figuring : 

Firstly,  the  ENTIRE  FACTORY  SELLING 
EXPENSE  IS  ELIMINATED— the  entire  output 
of  the  factory  being  sold  to  one  customer — the 
chain  store. 

The  saving  of  the  traveling  expense  and  sales- 
man's salaries  and  commissions.  The  saving  of 
advertising  and  promotion  expense.  The  added 
office  accounting  and  credit  expense.  All  these 
are  SAVED  by  the  chain  stores.  In  these  items 
alone  is  found  a  selling  cost  of  at  least  20  per  cent. 

On  top  of  that  the  JOBBERS'  DISCOUNT  OF 
40  PER  CENT  IS  WIPED  OUT. 

No  thinking  man  or  woman  has  to  be  told  that 
the  NET  SUM  the  manufacturer  receives  ALONE 
CONTROLS  THE  QUALITY  AND  QUAN- 
TITY of  materials  used  in  making  tires,  because 
ONLY  AND  SOLELY  from  this  NET  SUM  is 
the  PROFIT  derived. 

Because  of  the  TREMENDOUS  OVERHEAD 
selling  and  distributing  expense,  the  enormous  dis- 
counts demanded  by  the  jobber,  the  wholesaler  and 
the  retailer,  if  the  manufacturing  cost  were  TOO 
HIGH  or  even  over  his  competitors,  then  added 
charges,  as  described  here,  increase  out  of  propor- 
tion and  the  consumers'  prices  would  be  prohibitive. 

Hence,  in  National  Speedway  Tires  most  of  the 
factory  selling  cost  is  put  in  the  tire  in  ADDED 
QUALITY  AND  QUANTITY,  and  the  usual 
trade  discounts  are  divided  with  the  consumer. 

PROFITS  OF  CHAIN  STORES 

We  now  come  to  the  question  of  the  profits  of  the 
chain  stores  of  each  unit  and  of  the  chain  in  the 
aggregate. 

After  a  careful  scrutiny  of  costs  of  manufac- 
turing, of  operating  the  chain  store — each  unit — 
and  figuring  a  retail  price  on  the  tires  at  a  sensible 
reduction  over  average  price  of  tires  of  equal  size 
and  quality  we  find  that  there  is  still  possible  an 
average  margin  of  $5  per  tire.  This  is  "AVER- 
AGED" because  some  of  the  tires  will  pay  more 
profit  while  some  will  pay  less,  but  the  average  has  been  shown  to 
be  about  $5  per  tire  sold. 

This  is  evidently  a  CONSERVATIVE  ESTIMATE. 
If  each  chain  store  sells  ONLY  10  TIRES  PER  DAY,  we 
have  each  store  earning  a  profit  of  $50  a  day  or  $50,000  a  day 
profit  for  1,000  stores. 

$50,000  profit  per  day  for  365  days  in  the  year — tire  service 
stations  are  busier  Sundays  and  holidavs  than  other  davs — FIG- 
URES OUT  THE  ENORMOUS  TOTAL  OF  $18,250,000  A 
YEAR  PROFITS. 

You  will  realize  that  an  estimate  of  only  ten  tires  per  day 
is  very  small.  When  you  consider  the  tremendous  advantages 
of  dealing  with  the  National  Rubber  Company  service  stores, 
the  high  class  product,  the  low  price,  the  good  service  given  in 
the  way  of  instant  special  deliveries,  placing  the  tire  on  the  car 
and  taking  away  the  injured  tire  for  repairs,  it  is  not  hard  to 
understand  why  these  stores  should  do  an  enormous  business. 

Ten  tires  per  day  is  a  very  low  estimate  of  the  possibilities, 
but  to  be  even  more  conservative,  let  us  cut  down  this  estimate 
by  half.  Let  us  suppose  that  the  stores  onlv  AVERAGE  FIVE 
SALES  PER  DAY.    Let  us  see  how  this  figures  out. 

FIVE  TIRES  A  DAY,  showing  an  average  profit  of  $25  per 
day  per  store,  one  thousand  stores  will,  therefore,  pay  an  esti- 
mated daily  profit  of  $25,000.  For  365  davs  in  the  year,  THE 
ENORMOUS  TOTAL  WOULD  ■  BE  $9,126,000,  and  it  would 
be  a  mighty  small  store  that  couldn't  sell  five  tires  per  day. 


134 


THE  ELECTRICAL  EXPERIMENTER 


June,  1917 


These  figures  are  staggering  when  you  analyze  the  accumu- 
lated profits  of  hundreds  of  stores  all  over  the  country,  each 
contributing  its  quota  of  profits  from  many  sources. 

A  GOLD  MINE  OF  PROFITS 
You  will  note  that  no  estimate  has  been  made  of  profits  from 
sale  of  tubes  and  from  the  repair  department,  which  should  also 
be  profitable. 

It  will,  of  course,  take  time  to  build  up  such  a  large  chain 
of  service  stations,  but  in  a  few  years,  with  the  growth  of  the 
chain  and  the  enormous  increase  in  the  automobile  industry 
and  number  of  cars  in  use,  THIS  CHAIN  OF  TIRE  SERVICE 
STATIONS  SHOULD  BECOME  A  VERITABLE  GOLD 
MINE  OF  PROFITS  FOR  EVERY  STOCKHOLDER  WHO 
BECOMES  INTERESTED  IN  THIS  COMPANY  NOW,  when 
its  shares  can  be  acquired  at  a  low  initial  price. 

The  National  Rubber  Company,  of  New  York,  is  incorporated 


WHAT  THIS  MEANS  TO  AUTOISTS 

Let  us  study  it  over.  $50  invested  in  ten  shares  of  this  under- 
writing stock  will  save  the  automobile  owner  25  per  cent  on 
his  tires.  If  his  bill  for  tires  runs  to  $200  a  year,  he  will  be 
saved,  therefore,  $50.  That  means  that  the  stock  will  have  paid 
him  100  per  cent  on  his  investment  or  50  per  cent  on  the  par 
value  of  the  stock,  which,  computed  on  a  stock's  ability  to  earn 
5  per  cent,  will  make  his  TEN  SHARES  REPRESENT  AN 
INVESTMENT  OF  $1,000  FROM  AN  ORIGINAL  INVEST- 
MENT OF  $50.  Then  if  the  company  begins  paying  dividends, 
the  stock  should  go  to  par  and  over  if  the  dividends  amount 
to  more  than  5  per  cent. 

When  the  company  gets  on  a  10  per  cent  dividend  basis,  the 
stock  he  bought  for  $50  should  represent  an  investment  of  $200. 
When  it  pays  50  per  cent,  it  should  have  an  INVESTMENT 
VALUE  OF  $1,000, 


Section  of  Tire-making  Department.    Here  a  Small  Army  of  Workmen  Are  Constantly  Employed  Putting 
the  Finishing  Touches  to   National   Redwall   Speedway  Tires.     These  Workmen  Are  the  High-skilled 
Labor  and  Their  Rapidity  and  Efficiency  Are  Wonderful. 


under  the  laws  of  the  State  of  Delaware,  with  a  capitalization 
of  500,000  shares  of  the  par  value  of  $10  PER  SHARE,  ALL 
COMMON  STOCK,  SHARING  EQUALLY  IN  PROFITS 
AND  CARRYING  FULL  VOTING  POWER. 

THE  STOCK  IS  FULL  PAID  AND  NON-ASSESSABLE. 

For  the  purpose  of  establishing  the  business  on  a  right  basis, 
the  directors  have  set  aside  100,000  SHARES  OF  THIS  STOCK 
TO  BE  SOLD  TO  THE  PUBLIC. 

Their  idea  is  that  by  obtaining  a  wide  distribution  for  this 
stock,  they  will  enlist  local  interest  in  the  local  distributing  and 
service  stations  of  the  National  Rubber  Company. 

UNDERWRITING  STOCK  OFFER 
This  UNDERWRITING  SYNDICATE  STOCK  is  offered  in 
five  different  allotments. 

The  first  allotment  will  be  sold  in  lots  of  not  less  than  TEN 
SHARES  and  not  more  than  100  shares  at  $5  per  share,  or 
half  the  par  value  6f  the  stock. 

This  first  allotment  of  20,000  shares  is  the  only  stock  of  the 
UNDERWRITING  allotment  that  will  be  sold  at  this  low  price. 
The  next  allotment  will  probably  be  sold  at  from  40  to  50  per  cent 
advance  in  price  as  soon  as  the  first  allotment  of  20,000  shares 
is  disposed  of.  Further  allotments  at  further  increases  as  war- 
ranted. 

It  is  desired — as  nearly  as  possible — to  place  every  share  of 


So  when  the  company  is  in  a  position  to  pay  50  per  cent 
dividends,  this  stock  should  represent  an  investment  to  the  auto- 
mobile owner  of  $2,000,  figured  on  the  basis  of  the  dividends  and 
savings  it  will  give  him  on  his  tire  purchases.  And  all  from 
an  original  investment  of  $50. 

When  the  company  reaches  its  full  development  and  its  1,000 
or  more  stores  begin  piling  up  big  profits,  such  as  we  have  already 
ficured  on,  profits  that  mean  exceptional  dividends,  THIS  ORIG- 
INAL INVESTMENT  WILL  HAVE  ACCUMULATED  A 
PHENOMENAL  VALUE. 

NO  AUTOMOBILE  OWNER  CAN  AFFORD  TO  OVER- 
LOOK SUCH  AN  OPPORTUNITY. 

A  blind  man  could  see  the  possibilities  presented  in  this  under- 
writing offer,  an  offer  so  liberal  that  the  directors  had  to  confine  it 
to  a  small  amount  of  stock. 

AN  EXCEPTIONAL  OFFER 

The  offer  of  the  stock  at  $5  per  share  (par  $10)  is  in  itself 
a  tremendous  inducement,  but  when  it  is  coupled  with  the  offer 
of  the  company  to  extend  a  discount  of  25  per  cent  on  all  tire 
and  tube  purchases  made  through  the  company,  it  becomes  so 
extremely  attractive  a  proposition  that  NONE  CAN  AFFORD 
TO  IGNORE  IT. 

The  savings  in  tire  costs  alone  should  pay  for  the  stock  of 
those  who  accept  this  offer. 


The  Splendid  Modern  Character  of  This  Ideal  Plant  Is  Shown  Clearly  in  These  Pictures,  With  Its  Strong, 
Clear  Light,  Fine  Equipment  and  Good  Flooring.    Ideal  Conditions  for  Turning  Out  High-class  Work. 


this  UNDERWRITING  stock  in  the  hands  of  owners,  or  pros- 
pective owners,  of  automobiles,  who  will  become  immediate  pa- 
trons of  the  chain  stores  and  who  ARE  ALSO  OFFERED  AN 
INDUCEMENT  TO  BECOME  BOOSTERS  FOR  THE  TIRE 
SERVICE  STATIONS.  THIS  INDUCEMENT  CONSISTS 
OF  A  CASH  DISCOUNT  OF  25  PER  CENT  UNDER  THE 
STANDARD  LIST  PRICES  FOR  ALL  TIRES  SOLD  BY 
THE  NATIONAL  RUBBER  COMPANY  TO  ITS  SHARE- 
HOLDERS. 

An  automobile  owner,  therefore,  has  a  double  interest  in  buy- 
ing this  stock. 

The  saving  alone  in  tire  bills  for  a  year  should  pay  for  this 
ten  shares  if  he  buys  at  this  price  and  he  will  have,  besides 
the  savings  in  tire  costs,  and  dividends  which  the  company  de- 
clsrcs 

IS  THIS  INVESTMENT  WORTH  WHILE,  you  may  ask? 


This,  in  itself,  makes  the  proposition  attractive.  But  when  the 
future  of  this  company  is  analyzed  and  the  possibilities  it  offers 
are  considered,  the  offer  becomes  immensely  more  attractive. 

YOU  NEED  NOT  NECESSARILY  BE  AN  AUTOMOBILE 
OWNER  today  to  accept  this  offer.  Your  stock  in  the  National 
Rubber  Company  will  entitle  vou  to  this  25  per  cent  discount 
on  tires  and  tubes  JUST  AS  LONG  AS  YOU  REMAN  A 
STOCKHOLDER.  Later,  when  you  buy  an  auto,  you'll  be  able 
to  buy  tires  at  this  great  saving. 

You  often  hear  it  said  that  if  you  had  a  chance  to  invest 
with  Ford,  or  Willys,  of  Overland  fame,  with  Goodrich  or  Fisk 
or  Firestone ;  with  Westinghouse  or  Bell,  or  some  of  the  others, 
whose  companies  have  earned  fabulous  dividends,  and  made 
stockholders  rich,  you  would  today  be  ON  EASY  STREET. 

This  is  verv  true  but  the  pitiful  truth  is  YOU  DID  NOT  HAVE 
THIS  CHANCE.    VERY  FEW  PEOPLE  DID.    These  com- 


June,  1917 


THE  ELECTRICAL  EXPERIMENTER 


135 


panies  were  all  close  corporations  with  the  stock  held  in  the 
hands  of  a  small  group  of  men.  These  stocks  were  not  offered 
to  the  puljlic. 


Tire  Fabric  Cutting  Machine.    This  Machine  Can  Cut  the  Fabric  for 
1,000  Tires  a  Day,  Doing  the  Work  of  10  Men. 

A  CHANCE  IN  A  MILLION 

BUT  HERE  IS  A  CHANCE.  Here  is  a  company  offering 
UNDERWRITING  STOCK,  stock  that  can  now  be  bought  at 
the  ROCK  BOTTOM  PRICE,  that  should  in  time  become 
enormously  remunerative.  Stock  in  a  company  that  promises 
to  have  tremendous  growth. 

Woolworth  and  Whalen  and  the  others,  who  have  made  tens 
of  millions  out  of  chain  stores,  never  gave  the  public  a  chance 
to  come  in  on  the  organization.  They  have  sold  stock  since, 
lots  of  it  to  the  general  public,  but  it  has  been  stock  in  the 
developed  proposition,  stock  that  has  been  sold  on  the  market  AT 
THE  VALUE  IT  PRESENTS  NOW,  a  value  figured  on  the 
company's  earning  power. 

LATER  YOU  MAY  GET  A  CHANCE  on  the  National  Rub- 
ber Company  stock  on  the  open  market  but  YOU'LL  PAY  THE 
PRICE  OF  DEVELOPED  STOCK.    If  the  company  is  earn- 


Tire-Making  Machines.    A  Busy  Corner  in  This  Department.  These 
Four  Machines  Shown  in  the  Picture  Do  the  Work  of  40  Men.  This 
is  the  Most  Modern  Tire-making  Machine  Built. 

ing  100  per  cent  on  its  capitalization,  you'll  pay  for  it  at  that 
rate,  which,  in  that  case,  would  be  $2,000  for  every  $100  par 
value,  or  $200  a  share  for  $10  shares. 

THIS  IS  THE  PENALTY  THAT  SHORT-SIGHTED 
PEOPLE  PAY  for  not  accepting  opportunities  that  are  offered 
them. 

The  poorhouse  is  FULL  OF  SUCH  PEOPLE,  "THE  MIGHT- 
HAVE-BEENS." 

They  lacked  the  initiative  and  courage  to  back  their  belief 
with  their  money. 

THOSE  WHO  HAD  COURAGE 
The  others,  those  who  are  without  fear,  those  who  have  the 
courage  to  back  their  judgment  with  their  money,  they  are  those 
you  watch  spinning  past  you  on  the  boulevard   in  luxurious 
limousines,  whose  homes  line  the  fashionable  streets. 

MONEY  MAKES  MONEY,  but  it  takes  an  exceptional  op- 
portunity to  bring  you  big  returns  from  small  investments.  You 
read,  for  instance,  that  $500  invested  in  such-and-such  stock 
has  earned  $250,000 ;  that  $500  invested  in  such  other  stock  has 
paid  $200,000;  that  $1,000  in  Ford  stock  of  the  original  com- 
pany is  now  worth  millions.  THAT  IS  ALL  TRUE,  gospel 
truth,  BUT  did  YOU  ever  get  a  chance  to  invest  in  the  orig- 
inal $28,000  that  started  Ford  on  the  highroad  to  his  present 
millions?  Did  you  get  a  chance  to  invest  in  the  $33,000  that 
John  N.  Willys  has  built  up  into  the  tens  of  millions  of  the 
Overland  Company?  Did  YOU  get  a  chance  to  get  in  on  West- 
inghouse,  or  Bell  Telephone,  or  Western  Union,  or  Welsbach 
Mantles  stock?  Of  course  not.  And  very  few  people  did  BE- 
CAUSE THESE  STOCKS  WERE  NOT  OFFERED  TO  THE 
PUBLIC  when  they  were  at  a  low  price. 

THERE'S  A  REASON 
This  stock  is  offered  for  a  reason. 

It  is  offered  to  the  UNDERWRITERS  of  this  company  to 
start  it  with  a  nucleus  of  interested  tire  buyers  and  boosters  in 
every  locality. 

The  directors  set  A  MINIMUM  OF  TEN  SHARES  AND 
A  MAXIMUM  OF  100  SHARES  on  this  offer.  It  would  doubt- 
less be  more  profitable  to  the  company  if  every  subscription  for 
this  stock  was  for  $50  (10  shares),  par  value  $100,  because 
that  would  mean  that  the  greatest  number  of  people  possible 


Vulcanizing  Department  of  the  Pottstown  Plant.    Here  the  National 
Speedway  Tires  Are  Hardened  to  Stand  Wear  and  Tear.    This  De- 
partment is   Now  Vulcanizing   1,000  Tires  a  Day. 

would  be  holding  the  stock  and  boosting  for  the  company. 

Ten  thousand  holders  of  stock  scattered  throughout  the  coun- 
try would  mean  a  veritable  army  of  boosters,  helping  build  up 
the  business  IN  WHICH  EACH  ONE  HAS  A  SOLID,  SUB- 
STANTIAL INTEREST. 

Ten  thousand  boosters,  working  to  popularize  and  make  known 
the  high  quality  of  National  SPEEDWAY  RED-WALL  TIRES 
and  National  Red  Tubes — boosting  this  way  because  it  is  TO 
THEIR  INTEREST  to  boost  this  way— would  save  the  com- 
pany tens  of  thousands  of  dollars  per  annum  in  advertising  ex- 
pense. 

That's  the  principal  REASON  WHY  THIS  STOCK  IS  OF- 
FERED TO  YOU  AND  TO  EVERYONE  WHO  BUYS  TIRES 
OR  EXPECTS  TO  BUY  TIRES. 

It  is  WORTH  IT  to  the  company  to  make  you  EVERY  IN- 
DUCEMENT to  buy  this  stock.  AND  IT  IS  CERTAINLY 
WORTH  WHILE  TO  YOU  TO  BUY  IT.    Remember  you 


Rubber  Vault.    In  This  Vault  Are  Stored  Thousands  and  Thousands 
of  Pounds  of  Uncured  Rubber  for  Tire  and  Tube  Making.    It  is  Stored 
Here  Just  as  It  Comes  from  the  Ships. 

profit  immediately  because  as  soon  as  you  are  a  stockholder 
you  can  save  25  per  cent  on  all  the  tires  you  buy. 

WAITING  FOR  A  MIRACLE 

Every  man  hopes,  some  day,  that  by  some  wonderful  miracle 
he  will  be  lifted  out  of  the  life  of  drudging  toil  he  leads  into 
one  of  affluence,  comfort  and  independence.  It  is  our  nature 
to  live  in  this  HOPE.  But  the  day  of  miracles  is  past.  Good 
fairies  do  not  run  around  with  bags  of  gold  and  drop  them  into 
the  laps  of  the  worthy. 

YOU'VE  GOT  TO  HELP  YOURSELF  TO  FORTUNE. 
You've  got  to  save  to  get  a  nucleus  of  money  to  invest  where 


136 


THE  ELECTRICAL  EXPERIMENTER 


June,  1917 


Tube-making  Department.    Here  Are  Made  the  Famous  National  Red 
Tubes.    The  Factory  is  Producing  1,000  Tires  a  Day. 

the  opportunities  for  profit  are  large.  BUT  YOU'VE  GOT  TO 
INVEST  YOUR  SAVINGS,  if  you  want  them  to  pay  big  re- 
turns. 

One  of  the  world's  greatest  bankers  has  said  that  NO  MAN 
WILL  EVER  GET  RICH  FROM  THE  SAVINGS  OUT  OF 
A  SALARY  OR  WAGES.  He  must  accumulate  wealth  by 
PUTTING  THESE  SAVINGS  TO  WORK,  INVESTING 
THEM  TO  ADVANTAGE. 

Of  course,  it  takes  COURAGE  to  invest  money  that  you 
have  worked  hard  for,  that  has  been  slowly  and  laboriously 
accumulated  by  privations  and  sacrifices.  But  IT  IS  THE 
COURAGEOUS  WHO  WIN  THE  EARTH. 

DON'T  INVEST  ALL  YOUR  SAVINGS.  That  wouldn't  be 
the  wise  course.  Keep  a  reserve  of  your  savings  for  eventualities, 
for  sickness  or  loss  of  position  or  unexpected  calls,  BUT  IN- 


first  allotment  of  20,000  shares  at  $5  a  share  (par  value  $10  a 
share)  will  be  snapped  up  so  quickly  that  WE  CONFIDENTLY 
EXPECT  EVERY  SHARE  TO  BE  TAKEN  UP  WITHIN 
TEN  DAYS  from  the  publication  of  this  announcement.  After 
that,  there  will  be  no  more  $5  shares.  The  price  will  jump  per- 
haps 40  or  50  per  cent.   SO  ACT  NOW. 

Fill  out  the  convenient  coupon  attached.  Mail  it  with  your 
first  payment,  which  will  RESERVE  the  stock  you  want  at  this 
LOW  PRICE.  Then  you  can  take  fifteen  days  to  investigate, 
to  make  sure  that  all  the  facts  are  just  exactly  as  represented  to 
you.  If  you,  for  any  reason  whatever,  are  not  satisfied,  you  can 
release  your  reservation  and  your  money  will  be  returned  to  you, 
but  if  you  find  out  that  you  have  invested  wisely — as  we  are  confi- 
dent you  will  find  out — then  you  can  either  pay  the  balance  in  full 
or  you  can  take  advantage  of  the  easy  method  of  paying  for  it,  a 
little  each  month.  Either  plan  is  equally  satisfactory  to  the 
directors  of  the  National  Rubber  Company  of  New  York. 

IF  YOU  WANT  ANY  OF  THIS  UNDERWRITERS' 
STOCK,  YOU'VE  GOT  TO  WRITE  NOW,  at  once,  OR  YOU 
WILL  LOSE  YOUR  CHANCE. 


The  Magnificent  Pottstown,  Pa.,  Plant  of  the  National  Rubber  Company,  Where  National  Speedway  Redwall  Tires  and  National  Red  Tubes 
Are  Made.  Two  Floors  of  This  Big  Building  Are  Completed  and  Occupied.  This  Is  a  Strictly  Modern  Steel,  Concrete  and  Glass  Construc- 
tion Factory  Building  of  the  Highest  Type.    The  Big  Tire  Coming  Out  of  the  Building  is  the  National  Speedway  Redwall  Tire,  Best  on  the 

Market. 

VEST  PART  OF  YOUR  SAVINGS  WHERE  THEY  CAN 
EARN  YOU  SOMETHING  WORTH  WHILE. 

INVEST  FUTURE  SAVINGS 
Or  better  still,  HERE  IS  A  PLAN  BY  WHICH  YOU  CAN 
ACQUIRE  THIS  STOCK  WITHOUT  TOUCHING  YOUR 
SAVINGS. 

BUY  WHAT  YOU  CAN  AFFORD  TO  PAY  FOR  OUT  OF 
YOUR  NEXT  SAVINGS 
The  directors  have  made  it  EASY  FOR  YOU  TO  GET  THIS 
STOCK  AND  PAY  FOR  IT  OUT  OF  YOUR  FUTURE  SAV- 
INGS. 

You  can  pav  down  $10  ON  EVERY  TEN  SHARES  OF 
STOCK  YOU  WANT  AND  PAY  THE  BALANCE  IN  FOUR 
EQUAL  PAYMENTS  OF  $10  A  MONTH  for  each  10  shares, 
making  the  total  of  $50  for  the  ten  shares,  par  value  $100. 

This  liberal  plan  makes  it  possible  for  you  to  buy  this  stock 
and  pay  for  it  WITHOUT  TOUCHING  THAT  PRECIOUS 
CASH  RESERVE  you  have  been  accumulating  in  the  bank  so 
carefullv. 

BUT'  WHATEVER  YOU  DO,  DON'T  OVERLOOK  THIS 
OPPORTUNITY.    You'll  never  get  another  such  chance.  This 


How  You  Can  Buy  This  Stock 

10  shares  (par  value  $100) 

$10 

down,  $10  a  month  for  4  months  

$50 

15  shares  (par  value  $150) 

$15 

$75 

20  shares  (par  value  $200) 

$20 

down,  $20  a  month  for  4  months  

$100 

30  shares  (par  value  $300) 

$30 

down,  $30  a  month  for  4  months  

$150 

40  shares  (par  value  $400) 

$40 

down,  $40  a  month  for  4  months  

$200 

50  shares  (par  value  $500) 

$50 

$250 

$100  shares  (par  value  $1,000) 

$100  down,  $100  a  month  for  4  months  

$500 

APPLICATION  FOR   UNDERWRITERS'  SHARES 

E.  E. 

NATIONAL   RUBBER  COMPANY  OF  N.  Y.,  Pottstown,  Pa. 

Main  Office:  National  Rubber  Bldg.,  Broad  and  North  Sts.  „  , 

PHILADELPHIA,  PENNA.  Date  191.... 

The  undersigned  hereby  subscribes  for.  shares  of  the  Common  Stock  of  the 

National   Rubber  Company  of  New  York,  full  paid  and  non-assessable,    and    tenders   herewith  v--: 

(Bank  Check  or  Money  Order) 

to  the  order  of  National  Rubber  Company  of  New  York  for  $  ■   at  the  rate  of  $5.00 

per  share    J  full  }  payment, 
j  part  \ 

STOCKHOLDER'S  DISCOUNT — It  is  understood  that  in  consideration  of  this  subscription  as  long  as  I  remain 
a  shareholder  of  record  on  the  books  of  the  Company,  I  am  to  receive  a  Net  Cash  Discount  of  not  less  than  twenty- 
five  Per  Cent  (25  per  cent)  from  the  Company's  regular  Printed  Price  List,  on  -any  goods  listed  therein  which 
I  may  buy  for  my  own  use.  I  am  to  have  15  days  from  date  in  which  to  investigate  all  statements  made  by 
the  Company. 

Issue  shares  in  the  name  of   and  forward  to  addres  below: 

(Print  Name  Plainly) 

(Subscriber's  Signature)   


(Street  Address) 


(Town  and  State) 


Mr.  Edison's  y»v.;;.r.';i 

 — .  .'...j--^ — 


June,  1917 


THE   ELECTRICAL  EXPERIMENTER 


QUESTION  BOX. 

(Continued  from  page  130) 
former,  having  a  secondary  potential  of 
10,000  volts.  This  to  charge  a  group  of 
four  Murdock  block  condensers  that  will 
be  connected  in  parallel.  The  discharge  to 
take  place  in  a  quenched  spark  gap  linked 
to  a  primary  of  an  inductive  oscillation 
transformer.  The  secondary  to  be  connect- 
ed in  the  usual  way  to  the  antenna  and 
ground  terminals.  What  I  desire  to  know 
is  what  size  of  capacity  of  condenser  is 
required  to  reduce  the  wave  length  of  my 
oscillating  system  so  as  to  conform  to  the 
Government's  200  meter  wave  length  regu- 
lation? What  formula  do  you  employ  in 
determining  this  capacity? 

A.  2.  The  required  formula  is : 
X2  C 

Ci  =  ; 

3552  L  C  —  \ 

Where 

Ci  is  the  capacity  of  the  series  ground 
condenser  for  reducing  the  wave 
length 

Xi=wave  length  desired  (here  it  is  200 

meters) 
C  =  Capacity  of  the  antenna 
L  =  Inductance  of  antenna 
Having  calculated  the  values  of  the  capa- 
city of  the  antenna  .0004  mfd. ;  inductance 
62,090  cm.,  we  then  determine  the  desired 
capacity  by  substituting  in  the  above  for- 
mula and  we  get : 

(200)=  X  .0004 

Ci  =  - —    — ; 

3552  X  62090  X  .0004—  (200) 2 
Solving,   we   get   .003   micro-farad,  the 
capacity  of  the  condenser  necessary  to  re- 
duce the  wave  length  of  the  antenna  to  200 
meters.   

ELECTRON  DISCHARGE. 

(790.)  Louis  Bradenburg,  Little  Rock, 
Ark.,  wants  to  know  : 

Q.  1.  Does  the  effect  of  light  upon 
selenium  crystal  produce  a  purely  electronic 
discharge? 

A.  1.  This  question  is  still  in  the  hands 
of  some  prominent  physicists,  and  they  have 
not  come  to  any  conclusions  on  this  mys- 
terious problem,  and  for  this  reason  we  are 
unable  to  give  you  an  exact  answer.  We 
should  recommend,  however,  that  you  read 
an  article  on  selenium  in  this  issue,  written 
by  two  of  the  most  prominent  and  able 
scientists  on  this  subject. 

Q.  2.  I  have  had  an  idea  for  a  number 
of  years  to  make  an  electronic  detector  for 
converting  high  frequency  currents  to 
direct  or  pulsating  currents,  or  in  other 
words  an  instrument  similar  to  the  Fleming 
Valve  and  de  Forest  Audion.  Now  what 
I  desire  to  know  is,  what  chemical  will  pro- 
duce an  electronic  field  sufficiently  strong 
for  producing  the  same  effect  as  that  of  the 
lighted  filament?  Also,  was  there  any  such 
device  ever  made? 

A.  2.  Dr.  J.  A.  Fleming,  the  inventor  of 
the  Fleming  Valve,  has  built  electronic 
tubes  employing  an  exhausted  vessel  in 
which  an  amalgam  of  Sodium  and  Potas- 
sium was  placed  in  such  a  manner  that  it 
produced  an  electronic  field  when  a  beam 
of  light  was  focussed  upon  its  surface  and 
in  addition  a  secondary  plate  was  placed 
within  the  focus  of  the  electronic  stream. 
The  secondary  and  sodium-potassium  plates 
were  used  for  the  rectifier  circuit  of  the 
electronic  tube. 

The  two  most  generally  used  of  all  the 
metals  and  alloys  for  the  production  of  an 
electronic  field  are  chemically  pure  and 
highly  polished  rubidium  metal  and  an  alloy 
composed  equally  of  sodium  and  potassium 
metals.   

TONE  CIRCUIT. 

(791.)  Roy  Jansen,  Houston,  Tex., 
asks : 


MEDICINE   HAILS  ELECTRICITY. 

"The  day  of  the  howling  dervish  in  elec- 
tro-therapeutics is  past,"  declared  Dr.  S. 
Solis  Cohen  in  the  meeting  recently  of  the 
Philadelphia  County  Medical  Society,  "and 
the  science  now  has  a  definite,  dignified 
place  in  the  estimation  of  the  medical  pro- 
fession and  of  the  public." 

"We  must  confess  with  shame,"  said  Dr. 
S.  Lewis  Ziegler,  "that  the  greatest  ad- 
vances in  the  application  of  electricity  to 
medicine  have  come  thru  laymen  and  not 
doctors." 

Dr.  A.  B.  Hirsh  traced  the  history  of 
electro-therapeutics,  and  declared  that  an 
astonishingly  large  number  of  diseases  re- 
sponded to  electric  treatment. 

Q.  1.  What  does  a  "tone"  circuit  con- 
sist of  and  how  is  it  connected  to  a  radio 
transmitter  ? 

A.  1.  A  tone  circuit  consists  of  nothing 
more  than  an  oscillatory  circuit  shunted 
across  the  gap.  This  circuit  is  shown  here 
and  it  is  only  used  in  an  impulse  exciting 
transmitter  usually.  The  tone  circuit  is 
represented  by  the  oscillatory  circuit  L  Ci. 
A  large  capacity  and  a  small  inductance  is 
used. 

Q.  2.  Is  this  circuit  tunable?  If  so, 
how? 

A.  2.  The  tone  circuit  is  tuned  to  some 
multiple  or  sub-multiple  of  the  impulse 
frequency.  This  is  usually  accomplished 
by  varying  the  tone  circuit  condenser  capa- 
city. It  should  be  kept  in  mind,  that  a 
tone  circuit  does  not  improve  the  tone 
emitted  by  the  transmitter  in  every  type 
of  gap,  as  it  was  found  by  actual  experi- 
ment that  at  times  it  is  even  detrimental 
to  the  tone.  They  are  usually  employed 
on  low  tension  arc  or  spark  transmitters 
such  as  the  Von  Lepel  or  Chaffee  Arc. 


Arrangement  of  Tone  Circuit  in  the  Von 
Lepel  and  Chaffee  Arc   Radio  Transmitter. 


MAGNETIC  TELEPHONE. 

(792.)  William  Olsen,  Jamaica,  L.  I., 
desires  to  know : 

Q.  1.  What  is  the  principle  upon  which 
two  ordinary  telephone  receivers  when 
connected  together  can  transmit  the  human 
voice  from  one  place  to  another  by  talk- 
ing to  the  diafram  of  either  of  the  two 
receivers  ? 

A.  1.  The  principle  of  operation  of 
such  a  telephone  is  identical  to  the  pro- 
duction of  electric  current  by  a  dynamo- 
electric  machine,  in  that  when  a  magnetic 
field  is  permitted  to  be  interrupted  by  a 
wire  near  its  field,  a  current  of  electricity 
is  produced  in  that  wire  and  the  intensity 
of  the  generated  current  is  dependent  upon 
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vibrate  by  "talking,"  the  magnetic  flux  is 
varied ;  generating  a  current  in  the  coil 
which   operated  the  distant  receiver. 


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138 


THE  ELECTRICAL  EXPERIMENTER 


June,  1917 


Save  Dictating  Time 

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HIGH  FREQUENCY  PHENOMENA. 

(793.)    S.  Kohn,  Brooklyn,  N.  Y.,  asks: 

Q.  1.  Can  you  explain  the  following 
phenomena  which  I  recently  observed  dur- 
ing certain  experiments  which  I  have  car- 
ried on  with  a  Tesla  high  frequency  coil? 

A  large  primary  of  a  loose  coupler  was 
located  near  the  Tesla  coil ;  this  was  about 
3  feet  away  from  the  same,  and  it  was 
not  connected  to  anything.  As  the  Tesla 
transformer  was  set  in  operation,  I  have 
noticed  streaks  of  sparks  escaping  the 
winding  of  the  isolated  coil.  If  it  is  pos- 
sible, I  should  like  you  to  enlighten  me 
on  this  phenomena. 

A.  1.  The  phenomena  which  you  have 
observed  is  due  to  the  striking  resonance 
effect  existing  between  the  Tesla  coil  and 
the  primary  coil ;  since  the  resonance  was 
pronounced,  due  to  the  effect  noticed,  the 
electrical  energy  transformation  between 
the  produced  oscillations  of  the  high  fre- 
quency coil  and  that  of  the  isolated  coil  is 
at  maximum  ;  consequently,  the  discharge 
of  sparks  from  the  coil  was  produced. 
These  resonance  high  tension  and  fre- 
quency experiments  were  carried  out  first 
by  Nikola  Tesla,  and  he  was  able  to  ob- 
tain sparks  which  reached  in  magnitude 
from  five  to  six  feet  in  length. 


TRANSFORMER  FORMULA. 

(•794.)  L.  Kennedy,  Los  Angeles,  Cal., 
wants  to  know  : 

Q.  1.  In  the  design  of  a  radio  trans- 
former, what  are  the  most  important  pre- 
cautions that  must  be  taken  in  order  to 
build  an  efficient  transformer? 

A.  1.  There  are  a  few  important  steps 
that  the  designer  must  observe  when  de- 
signing a  transformer,  namely  :  the  voltage 
transformation  between  the  primary  and 
secondary,  the  latter  should  be  made  to 
correspond  with  the  proper  sending  con- 
denser capacity,  and  this  must  be  obtained 
beforehand ;  the  proper  arrangement  of 
secondary  pies,  separated  with  proper  in- 
sulation, and  finally,  the  magnetic  circuit 
in  which  great  care  must  be  exercised  in 
designing  the  same,  as  75  per  cent  of  the 
eiheiency  will  be  in  this  magnetic  circuit. 
The  proper  number  of  cubic  inches  of  core 
is  at  first  found;  this  is  then  split  up  into 
suitable  form,  the  legs  of  which  should 
correspond  to  the  primary  and  of  the  sec- 
ondary windings. 

Q.  2.  What  is  the  relation  existing 
between  the  primary  winding  and  voltage 
of  a  transformer? 

A.  2.  The  relation  of  the  two  factors  is 
exprest  by  the  following  formula : 

10s  X  £P 

Nv  =  — —  

V2t  fBAc 

Where 

Nv  =  Number  of  turns  on  primary  wind- 
ing 

Ev  =  Voltage  across  primary 
f  —  Frequency. 

B  =  Magnetic  flux  of  core  (per  sq.  cm. 

of  cross-section  of  the  iron  core) 
A<-  =  Area  (express  in  square  centime- 
ters  of   the   cross-section   of  the 
iron  core) 

Q.  3.  What  do  you  consider  the  best 
insulation  material  for  covering  the  core 
when  the  winding  is  to  be  made? 

A.  3.  Empire  cloth  is  very  excellent  for 
this  work  and  it  is  universally  employed 
for  this  purpose. 


THE  "BROWN"  TELEPHONE 
RELAY. 

(795.)  Frank  Vontair,  Philadelphia, 
Pa.,  desires  to  know: 

Q.  1.  Is  the  "Brown"  relay,  which  is 
used  in  England,  a  microphone  device? 

A.   1.  This    type    of    instrument    is  a 


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June,  1917  THE  ELECTRICAL  EXPERIMENTER  139 


purely  microphonic  device  and  the  micro- 
phone is  controlled  by  a  super-sensitive 
telephone  relay.  A  more  complete  detail 
of  this  device  was  published  in  the  Au- 
gust, 1915,  issue  of  this  journal. 


1:5  wit  cell  ~i   ^Ot)  f~\ 


Brown  relay 


Trans f hoard 


Connection  of  the  "Brown"  Amplifying  Relay 
in  the  Circuit  of  a  Radio  Receptor. 

Q.  2.  What  is  the  binding  post  connec- 
tions of  this  relay?  How  is  it  connected 
to  a  wireless  receiving  set? 

A.  2.  The  accompanying  diagram  gives 
the  connections. 

Q.  3.  Are  these  instruments  used  ex- 
tensively in  this  country? 

A.  3.  No,  they  are  mostly  used  abroad, 
especially  in  England. 


MERCURY  RECTIFIER. 

(796.)  Thomas  Pierson,  Richmond,  Va., 
wants  to  know : 

Q.  1.  What  is  the  efficiency  of  a  mer- 
cury arc  rectifier  ? 

A.  1.  The  efficiency  of  this  device  varies 
with  circumstances  and  depends  largely 
upon  the  load  voltage.  There  is  a  cer- 
tain drop  or  lost  voltage  in  the  tube, 
usually  15  to  25  volts,  which  is  practi- 
cally independent  of  the  load  and  the  en- 
ergy thus  represented  appears  as  light  and 
heat.  So  if  a  set  was  delivering  current 
at  a  potential  of  15  to  25  volts,  its  effi- 
ciency under  these  conditions  would  be, 
roughly  speaking,  about  50  per  cent.  But 
this  is  rarely  the  case,  and  in  most  com- 
mercial installations  of  constant  potential 
sets,  the  full-load  efficiency  is  over  80  per 
cent  and  the  efficiency  of  most  constant 
current  sets  will  be  over  90  per  cent  at 
full  load. 

Q.  2.  What  is  the  life  of  a  mercury 
rectifier  tube? 

A  2.  The  average  life  is  about  700 
hours,  but  many  cases  are  known  where 
the  tubes  have  run  much  longer. 

Q.  3.  What  is  the  power-factor  of  such 
a  rectifying  system  ? 

A.  3.  On  a  50  light  set  the  power-fac- 
tor on  the  primary  of  the  constant  current 
transformer  is  about  65  per  cent.  On  con- 
stant potential  systems  it  may  reach  as 
high  as  90  per  cent. 


MEASUREMENT    OF  IRREGULAR 
AREA. 

(797.)  Paul  Andel,  New  Orleans,  La., 
asks : 

Q.  1.  What  are  the  principal  methods 
for  determining  the  area  of  an  irregular 
plane  surface  such  as  those  obtained  from 
indicator  cards,  etc.? 

A.  1.  There  are  three  general  methods 
for  obtaining  the  area  value  of  irregular 
plane  surfaces  and  the  simplest  of  the  three 
is  by  employing  a  "planimeter"  instrument, 
a  device  which  automatically  figures  out 
the  area  of  the  plane  in  question.  Such 
an  instrument  consists  of  a  wheel  of  defi- 
nite circumference,  which  revolves  when 
the  lever  attached  to  this  wheel  is  caused 
to  trace  the  perimeter  of  the  irregular 
surface. 

A  second  method  is  by  forming  a  large 
number    of    small     squares     within  the 
(Continued  on  page  140) 


BOOK  REVIEW  [ 

The  Submarine  Torpedo  Boat.  By  Allen 
Hoar.  Cloth  covers ;  size  8x5-)4  inches ; 
212  pages,  84  illustrations  and  4  folding 
plates.  Price,  $2.00.  Publisht  by  D.  Van 
Nostrand  Co.,  New  York  City,  1916. 

One  or  tile  most  valuaure  and  popular  treatments 
of  this  all-important  subject  which  is  at  the  pres- 
ent time  of  interest  to  readers  of  all  classes. 
Unlike  a  great  many  books  of  this  nature  dealing 
with  such  a  specific  and  technical  subject  as  the 
submarine  torpedo  boat,  Mr.  Hoar  has  given  us 
a  well-written  and  lucid  description  of  this  mar- 
velous twentieth  century  war  machine.  The  en- 
gineer and  layman  will  both  profit  by  perusing  the 
interesting  chapters  of  this  authoritative  writer, 
who  is  a  junior  member  of  the  American  Society  of 
Civil  Engineers.  The  various  chapters  take  up  the 
early  history  and  development  of  the  submarine 
torpedo  boat,  and  contain  some  very  interesting  il- 
lustrations and  photographs  of  practically  every 
distinct  type  of  submarine  ever  built.  The  suc- 
ceeding chapters  deal  with  the  development  of  the 
present  day  submarine;  its  characteristics  and  re- 
quirements; types  of  submarines;  the  design  of 
the  submarine  torpedo  boat;  the  power  plant; 
means  of  defense  against  submarine  attack;  tacti- 
cal evolutions  of  the  submarine;  the  torpedo; 
tenders  and  salvage  ships;  submarine  mines,  etc. 

Some  of  the  most  interesting  sections  of  the 
book  deal  with  the  approved  manner  of  maneuver- 
ing a  submarine  in  order  to  torpedo  an  enemy 
vessel,  and  also  discuss  authoritatively  the  various 
technical  aspects  developing  in  the  general  opera- 
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American  Boy's  Book  of  Electricity.  By 
Charles  H.  Seaver.  Cloth  covers;  size 
8x6  inches;  366  pages,  313  illustrations. 
Price,  $1.50  net.  Publisht  by  David  Mc- 
Kay, Philadelphia,  Pa. 

The  American  boy  is  always  interested  in  a 
good  book  treating  on  electrical  experiments  of  a 
practical  and  interesting  nature.  There  have  been 
a  great  many  books  written  in  the  past  few 
years,  intended  for  the  electrically  inclined  youths 
of  the  land,  but  we  do  not  remember  seeing  a 
more  worthy  volume  in  a  long  time  than  here 
presented  by  Mr.  Seaver.  The  volume  is  pro- 
fusely illustrated  with  clear-cut  drawings,  which 
can  be  readily  understood  by  young  boys  of  from 
ten  to  fourteen  years,  and  all  of  the  important 
fundamental  magnetic  and  electrical  laws  with 
their  accompanying  actions  and  reactions  have 
been  cleverly  and  interestingly  woven  thru  the 
experiments  outlined. 

A  number  of  excellent  half-tone  illustrations  are 
inserted,  showing  modern  electrical  appliances,  so 
that  as  the  boy  studies  the  different  experiments 
and  simply  explained  laws,  he  will  also  be  given 
a  clear  understanding  of  the  relation  between 
such  experimental  apparatus  and  the  commercial 
instruments  and  appliances.  Mr.  Seaver  is  to  be 
congratulated  upon  the  adaptness  with  which  he 
has  combined  these  two  important  fields  of  elec- 
trical endeavor,  so  that  the  young  reader  will 
not  become  confused  or  discouraged  by  his  in- 
ability to  understand  the  underlying  theory  of  the 
apparatus  described. 

The  book  describes  how  to  build  substantial  ex- 
perimental apparatus  such  as  small  dynamos  and 
motors;  induction  or  spark  coils;  telephone  and 
telegraph  apparatus;  a  complete  wireless  station 
of  improved  design;  how  to  do  simple  house  wir- 
ing in  accordance  with  the  standard  rules;  how 
to  wire  ignition  circuits  on  gasoline  engines  of 
the  single  and  multiple  cylinder  type;  how  to 
build  small  transformers  and  the  principles  upon 
which  they  operate;  how  to  build  primary  and 
storage  batteries;  the  action  of  lightning  discharges 
and  how  to  protect  buildings  from  them,  and  also 
a  considerable  number  of  electrical  experiments 
in  static  electricity.  We  strongly  recommend  this 
book  to  the  American  boy. 


Examples  in  Alternating  Currents. 
Vol.  1,  Second  Edition.  By  Prof.  F.  E. 
Austin,  B.S.,  E.E.  Flexible  green  leather 
covers,  pocket  style ;  size  7]/2x5  inches ; 
224  pages,  75  illustrations  with  numerous 
tables.  Price,  $2.40.  Publisht  bv  the 
Author  at  Hanover,  N.H. 

The  second  edition  of  this  valuable  treatment 
of  alternating-currents  contains  a  number  of  ad- 


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□  ELECTRICAL  ENGINEER 
Z]  Electrician 

□  Electric  Wiring 
~3  Electric  Lighting 

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140 


THE  ELECTRICAL  EXPERIMENTER 


June,  1917 


A  call  for  Mr.  Smith 
who  has  Code  Num- 
ber 32. 


NATIONAL 
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hunting  by  the  dragnet  process — com- 
pelling employees  in  perhaps  every 
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phone call. 

The  money  saving  answer  to  this 
problem  is  "Don't  use  the  telephone  at 
all  to  hunt  men."  Allow  it  to  be  used 
only  after  the  man  has  been  found  by 
the  aid  of  the  National  Calling  System, 
which  summons  him  instantly,  no  matter 
where  he  may  be  about  your  establish- 
ment or  grounds.  The  man  called  then 
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directly  with  the  man  who  sought  him. 
No  one's  time  is  wasted,  no  one's  work 
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ditions  and  revisions,  and  will  be  found  extremely 
valuable  to  ail  students  of  this  subject.  Some  01 
the  more  practical  examples  given  in  alternating- 
current  calculations  involve  frequency,  power  fac- 
tor, harmonics,  induced  A.C.  pressures,  and  tne 
various  specific  values  of  A.C.  potential,  such  as 
the  instantaneous  and   effective   values,  etc.,  etc. 

Many  practical  problems  are  explained  by  means 
of  examples,  and  in  accordance  with  the  best 
modern  methods,  covering  such  topics  as  the  ad- 
dition of  sine  pressures;  the  product  of  sine 
curves  having  the  same  frequency  but  different 
phase  displacements;  the  calculation  and  measure- 
ment of  inductance  coils,  including  the  simple 
measurements  of  this  important  factor  by  means 
of  a  volt  meter,  ammeter  and  frequency  meter, 
and  including  the  new  inductance  formula  due  to 
Brooks  and  Turner.  Further  sections  of  the  work 
treat  on  the  inductance  of  transmission  lines  and 
various  current  and  voltage  relations,  etc..  when 
two  or  more  impedances  are  connected  in  series 
or  in  parallel.  Also  the  method  of  computing 
capacity  of  condensers,  and  the  current  taken  by 
them  when  connected  to  A.C.  circuits.  The  work 
concludes  with  a  number  of  valuable  tables  con- 
taining the  products  of  2  x  pi  x  frequency,  and 
modifications  of  this  expression,  which  are  used  so 
frequently  in  alternating-current  computations. 


How  To  Make  Low  Pressure  Transform- 
ers. Third  Edition,  by  Prof.  F.  E.  Aus- 
tin, B.S.,  E.E.  Board  covers;  size 
7j4*4?4  inches;  22  pages,  16  illustrations. 
Price  40  cents.  Publisht  by  the  author 
at  Hanover,  N.H. 

Another  addition  of  Prof.  Austin's  treatise  on 
the  design  and  construction  of  small,  low-pressure 
transformers  which  has  found  considerable  favor. 
The  work  takes  up  numerous  practical  operations 
to  be  followed  in  constructing  step-down  trans- 
formers for  ringing  bells,  and  for  other  opera- 
tions, and  also  a  design  for  a  transformer  giving 
as  high  as  174  volts  when  run  on  a  110  volt  A.C. 
circuit.  Data  is  given  for  these  transformers  for 
use  also  on  220  volts,  60  cycle  A.C.  circuit.  The 
text  matter  is  written  in  a  clear  manner  which 
can  be  followed  by  any  amateur  and  the  illustra- 
tions are  made  in  perspective  so  as  to  show  ex- 
plicitly just  how  the  various  iron  core  strips  are 
assembled  and  clamped  together,  and  also  how  the 
coil  windings  may  be  wound  in  sections  to  sim- 
plify the  construction. 


Apflied  Electricity  For  Practical  Men. 
By  Prof.  Arthur  J.  Rowland.  Cloth 
covers;  size  5x7}^  inches,  375  pages,  323 
illustrations.  Price,  $2.00.  Publisht  by 
the  McGraw-Hill  Book  Co.,  New  York 
City. 

This  book  has  been  prepared  by  an  author  of 
wide  experience  in  teaching  practically  and  theo- 
retically the  subject  to  students,  and  he  has  in- 
corporated many  valuable  ideas  in  the  matter  pre- 
sented. We  believe  this  work  should  prove  ex- 
tremely valuable  to  electricians  of  all  classes,  as 
it  contains  all  the  fundamental  electrical  principles 
which  are  discust  in  an  approved  yet  somewhat 
new  manner,  and  gradually  the  student  is  intro- 
duced to  the  principles  and  practical  operating 
features  of  dynamos;  motors;  electric  heating  ap- 
paratus; the  wiring  of  switchboards  and  power 
plants;  principles  of  the  electric  trolley  system; 
alternating-current  systems,  including  the  various 
types  of  commercial  transformers,  and  just  how 
they  operate  and  why;  poly-phase  current  prin- 
ciples; alternating-current  motors;  storage  bat- 
teries; electric  circuits  and  wires  and  wiring. 

Unlike  many  volumes  of  this  nature,  the  author 
has  seen  fit  to  not  only  explain  each  subject  in 
simple  language  at  the  start,  but  also  to  give  the 
elementary  formulas  governing  the  theory  and 
operation  of  these  various  electrical  apparatus  and 
circuits.  The  general  electrical  student  will  find 
this  work  of  distinct  value,  and  to  enhance  the 
value  of  each  lesson  he  has  studied,  there  are  a 
number  of  questions  and  problems  given  at  the 
end  of  each  chapter  which  the  student  can  work 
out. 


The  Science  of  Musical  Sounds.  By 
Prof.  •  Dayton  Clarence  Miller,  D.Sc. 
Cloth  covers ;  size  8-)4x6  inches,  286 
pages,  187  illustrations.  Price,  $2.50. 
Publisht  by  the  MacMillan  Co.,  New 
York  City,  1916. 

This  work  by  Prof.  Miller  treating  on  the  science 
of  musical  sounds  is  one  of  the  most  pretentious 
science  works  that  we  have  ever  reviewed.  A 
vast  array  of  sound  producing  and  analyzing  appa- 
ratus of  both  simole  and  comolicated  structure 
are  described  and  illustrated.  The  text  matter  is 
exceedingly  clear,  and  can  be  readily  understood 
by  any  student  of  music  or  physics.  The  author 
starts  off  with  the  definition  of  sound,  and  pro- 


ceeds to  give  many  illuminating  details  that  the 
average  physics  student  will  find  both  new  and 
interesting. 

Every  conceivable  form  of  tuning  fork  and  siren 
for  producing  sounds  of  any  pitch  or  frequency 
is  profusely  illustrated  and  described.  Among 
the  subjects  discust  in  a  popular  scientific  manner, 
so  that  it  may  be  enjoyed  by  the  lay  reader  as 
well  as  the  student  of  pure  physics,  are  the  action 
of  organ  pipes  (including  illustration  of  an  organ 
pipe  over  32  feet  in  length  and  giving  sixteen 
vibrations  per  second;,  and  such  further  prac- 
tical considerations  as  standard  tuning  forks;  the 
law  of  tone  quality;  the  manometric  capsule  and 
revolving  mirror,  and  also  the  use  of  the  phono- 
graph and  Professor  Miller's  own  invention,  the 
"Phonodeik,"  by  which  apparatus  it  has  become 
possible  to  intercept  a  sound  wave  such  as  a 
person's  voice,  and  to  project  these,  magnified 
many  hundred  times,  upon  a  screen  so  that  the 
voice  fluctuations  can  be  studied  by  a  large  body 
of  students.  The  phonodeik  is  so  remarkably  sen- 
sitive to  sound  waves,  that  it  will  respond  to  a 
frequency  of  ten  thousand  complete  vibrations  per 
second. 

The  subject  of  harmonics  has  received  special 
attention,  and  considerable  discussion  is  given  on 
the  different  types  of  harmonic  analyzers,  includ- 
ing the  remarkable  machine  as  used  by  the  U.S. 
government  for  predicting  the  rise  and  fall  of 
tides.  Among  other  interesting  subjects  covered 
in  this  book,  we  find  oscillogram  curves  of  the 
voices  of  such  famous  singers  as  Signor  Caruso 
and  Amato.  Also  such  an  interesting  subject  as 
the  influence  of  horns  on  sound,  and  the  import- 
ance of  diaframs  in  certain  instruments.  The 
principle  of  musical  instruments,  such  as  the 
piano,  flute  and  violin  are  discust,  and  the  music 
produced  by  them  shown  grafically  by  means  of 
oscillogram  curves.  One  of  the  most  interesting 
chapters  is  that  treating  on  synthetic  vowels  and 
words,  and  the  relation  of  the  art  and  science  of 
music  which  is  illustrated  by  many  remarkable 
cuts  of  apparatus  which  have  been  developt  for 
emitting  vowel  sounds. 

A  remarkable  illustration  is  that  showing  the 
large  group  of  organ  pipes  necessary,  which  when 
sounded  simultaneously  reproduce  the  vowel  a,  as 
in  "mat,"  and  still  another  illustration  shows  the 
vast  number  of  organ  pipes  required  to  reproduce 
the  principal  vowels  synthetically. 


QUESTION  BOX 

(Continued  from  page  139) 
boundary  of  the  plane  surface,  and  deter- 
mining the  area  of  one  of  these  squares, 
then  multiplying  the  area  of  each  by  the 
total  number  of  them  within  the  surface. 
This  will  give  an  approximate  area,  since 
it  is  impossible  to  erect  squares  close 
enough  to  the  irregular  curves  of  the 
plane  surface. 

The  third  and  most  accurate  method  is 
by  the  use  of  higher  mathematics :  where 
a  limiting  value  of  the  maximum  and  min- 
imum peaks  of  the  perimeter  of  the  sur- 
face is  obtained  by  actual  measurement, 
and  substituting  this  value  in  an  integral 
equation  as  used  in  the  Calculus.  Some 
engineers  weigh  a  sq.  cm.,  nr  inch  of  the 
chart  paper  and  then,  by  a  simple  calcula- 
tion, compute  the  area  of  the  irregular 
surface. 


WHEATSTONE  bridge  circuit. 

(798.)  John  Brown,  San  Diego,  Cal., 
wishes  to  know : 


How  a   Reversing    Key    Is  Connected   in  a 
Wheatstone  Bridge. 


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June,  1917 


THE   ELECTRICAL  EXPERIMENTER 


141 


Q.  1.  How  are  the  connections  made  of 
a  Post  Office  type  of  Wheatstone  bridge 
so  that  the  resistance  arms  are  reversed 
in  the  circuit?  I  understand  this  arrange- 
ment is  used  in  eliminating  errors  in  meas- 
urements which  may  be  due  to  polarity 
interferences  acted  upon  the  galvanometer. 

A.  1.  The  diagram  herewith  gives  the 
proper  connections  of  the  instrument  you 
mention.  The  reason  for  reversing  the 
connections  of  resistance  arms  is  to  elim- 
inate the  errors  produced  by  cross-cur- 
rents in  the  circuit.  By  obtaining  two  sets 
of  readings  for  both  reversed  positions  of 
the  arms,  such  errors  are  limited  to  a 
minimum. 

ALUMINUM  QUERIES. 

(799.)  Joseph  Hassel,  Boston,  Mass., 
asks : 

Q.  1.  What  are  the  ores  used  in  the 
production  of  commercial  aluminum? 

A.  1.  Aluminum  oxid  is  the  main  source 
out  of  which  aluminum  is  extracted.  Baux- 
ite, a  hydrated  oxid  of  aluminum,  is  ex- 
tensively used. 

Q.  2.  How  is  the  metallic  aluminum  ob- 
tained ? 

A.  2.  The  only  process  used  at  present 
for  the  extraction  of  aluminum  is  an  elec- 
trolytic one.  The  electrolyte  consists  of  a 
solution  of  aluminum  oxid  in  melted  cryo- 
lite. The  cryolite  is  not  decomposed,  but 
serves  as  a  solvent  only.  The  mineral 
Bauxite  is  used  to  furnish  the  oxid.  The 
cryolite  is  fused  and  kept  liquid  by  the 
heat  .generated  during  the  passage  of  the 
current ;  the  dissolved  aluminum  oxid  is 
separated  into  aluminum  and  oxygen  by 
the  current.  The  aluminum  collects  as  a 
molten  mass  in  the  bottom  of  the  melting 
pot;  the  oxygen  is  liberated  at  the  anodes, 
which  are  oxydized  by  it.  The  weight  of 
the  anodes  consumed  about  equals  the 
weight  of  the  aluminum  liberated. 


TELEVISION. 

(800.)  Thomas  Jelinder,  Hartford, 
Conn.,  asks  : 

Q.  1.  Was  television  ever  brought  to  a 
practical  stage? 

A.   1.  No. 

Q.  2.  What  method  did  Mr.  Ernest 
Ruhmer  of  Berlin  use  for  his  television 
apparatus  ? 

A.  2.  He  employed  a  large  number  of 
selenium  cells  placed  before  a  similar  num- 
ber of  lenses.  Each  of  these  cells  corre- 
sponded to  a  "single  eye,"  similar  to  the 
human  eye,  and  the  reflection  of  light  from 
the  object,  the  image  of  which  was  to  be 
transmitted,  was  caused  to  fall  upon  the 
various  selenium  cells.  These  cells  were 
connected  to  a  corresponding  number  of 
electro-magnets  which  controlled  a  num- 
ber of  diaframs.  These  diaframs  were  set 
in  operation  in  unison  with  their  proper 
selenium  cells  at  the  transmitting  station. 
A  rectangular  image  was  possible  with  this 
arrangement.  It  was  used  to  transmit  let- 
ters, as  it  was  imperfect  enough  to  be  used 
to  differentiate  the  actual  colors  of  a  pho- 
tograph or  image  of  a  human  countenance. 

A  number  of  suggestions  have  been 
made  to  develop  a  television  scheme,  but 
the  inventors  only  went  as  far  as  making 
suggestions,  but  never  went  into  the 
trouble  of  bringing  out  their  ideas  experi- 
mentally. 


TRANS-PACTFIC    RADIO  COMMU- 
NICATION SUSPENDED. 

Wireless  communication  to  Hawaiian 
territory  beyond  Honolulu  has  been  sus- 
pended. Messages  to  other  islands  will  be 
mailed  from  Honolulu. 


AM1RICAJI  , 
TECHNIC  AJ, 
SOCIETY 


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142 


THE   ELECTRICAL  EXPERIMENTER 


June,  1917 


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M.  A.  F.  Loading  Coil.  . 


$18.00 
75.00 

22.50 
100.00 

35.00 
1.00 
3.00 
2.00 


MULTI-AUDI-FONE 

275  Morris  Ave.  Elizabeth,  N.  J. 

Send  2c  for  Circular 


New  Undamped  Wave  Coupler  No.  749 

Special  Introductory  Price,  $18.00 

Our  new  coupler  No.  749  is  32"  loug,  9*  wide,  and 
10"  high,  overall,  and  on  an  average-sized  Antenna 
tunes  to  15.000  meters.  This  coupler,  used  with  the 
new  CHAMBERS'  SYSTEM  or  CIR- 
CUIT, will  bring  in  signalsfrom  domestic 
and  foreign  Arc  Stations  surprisingly 
loud  and  clear.  Note  the  difference  in 
size  of  our  No.  748  and  No .  749. 
We  claim  to  be  the  original  inventors  of 
a  SYSTEM  or  CIRCUIT  for  the  recep- 
tion of  the  undamped  waves  without  the 
use  of  Loading  Coils  or  Oscillating  Coils, 
as  they  are  sometimes  called;  as  with  our 

SYSTEM  or  CIRCUIT  only  two  Inductively 
Coupled  Coils  are  necessary.  Circuit  supplied 
with  each  coupler. 

This  CHAMBERS'  CIRCUIT  saves  you  money. 
_  to  pay  for.  and  price  of  coupler  only  $18.00.    Place  order 
the  introductory  price.   Orders  filled  in  rotation.   Send  for 

descriptive  matter. 

F.  B.  CHAMBERS  &  CO.,  2046  Arch  St.,  Phila.,  Pa. 


CHANCES    FOR  ELECTRICIANS 
IN  THE  NAVY. 

(Continued  from  page  86) 
reciprocating  steam  engines,  steam  turbines, 
internal-combustion  engines,  magnetism  and 
electricity,  dynamos,  motors,  motor-gener- 
ators, alternating  currents,  interior  commu- 
nication, lighting,  batteries,  etc.  Members  of 
the  radio  class  are  trained  in  all  the  duties 
of  a  radio  operator  and  are  given  constant 
practice  in  the  use  of  all  the  apparatus  em- 
ployed in  radio  and  especially  in  receiving 
and  sending  by  the  systems  employed  in 
the  Navy. 

Enlistments  in  the  Navy  are  for  a  period 
of  four  years.  A  man  will  not  be  ad- 
vanced to  chief  electrician  (with  rank  of 
'chief  petty  officer)  during  his  first  enlist- 
ment, but  he  may  be  recommended  for  that 
position  towards  the  completion  of  his  first 
enlistment,  with  a  view  to  advancement 
upon  re-enlistment  if  any  vacancy  exists. 


NEW    METHOD    OF  MEASURING 
PRESSURE  OF  LIGHT. 

(Continued  from  page  102) 
The  32  c.p.  lamp  was  enclosed  in  a  metal 
box  whose  front  face  had  been  replaced  by 
a  glass  screen  covered  with  a  few  thin 
wires.  Inasmuch  as  it  is  required  that  the 
radiation  should  be  normally  incident,  the 
lamp  was  not  brought  too  close  to  the  tube, 
a  calculation  of  the  limiting  approach  hav- 
ing been  previously  made.  The  current 
passing  thru  the  lamp  was  maintained  at 
the  same  value  thruout  all  the  experiments. 
The  reflecting  and  transmitting  powers  of 
the  foils  used  were  then  tested.  Gold  and 
aluminum  reflected  90  per  cent  of  incident 
radiation. 

Calculation  of  the  Deflection  of  the  Strip. 
— Since  the  foil  reflects  90  per  cent  of  the 
incident  radiation,  and  since  7  per  cent  is 
reflected  from  the  glass  of  the  tube,  the 
total  pressure  of  the  radiation  is  given  by 

£(1+007x0-9)  (1+0-9)  or204£, 
where  E  is  the  energy  density  of  the  inci- 
dent beam. 

A  certain  amount  of  radiation,  however, 
strikes  the  back  of  the  glass  tube,  and  some 
of  this  is  reflected  to  the  back  of  the  strip. 
For  a  strip  three-quarters  the  width  of  the 
tube  it  is  estimated  that  the  normal  compo- 
nent of  this  radiation  is  about  1  per  cent  of 
all  that  is  incident  on  the  strip.  It  is, 
therefore,  necessary  to  substitute  2.02£  for 
2.04£. 

It  can  be  shown  that  a  uniform  flexible 
strip  when  deflected  by  a  small  uniform 
pressure  still  remains  straight.  To  a  close 
degree  of  approximation,  therefore,  we  may 
calculate  the  deflection  of  a  strip  such  as 
that  represented  in  Fig.  1  by  taking  mo- 
ments about  the  axis  of  rotation.  The  de- 
tails of  apparatus  used  are  given  in  the 
original  paper,  as  well  as  the  thermo-kinev- 
ic  reaction  and  a  table  of  results  observed 
in  succession. 


ELECTROLYSIS  SURVEY  PRO- 
POSED IN  MONTGOM- 
ERY, ALA. 

The  Bureau  of  Standards  has  been  asked 
to  make  an  electrolysis  survey  in  Mont- 
gomery, Ala 


You  benefit  by  mentioning  "The  Electrical  Experimenter"  when  writing  to  advertisers. 


June,  1917 


THE   ELECTRICAL  EXPERIMENTER 


143 


DENVER    WIRELESS  STATION 
WINS  PRIZE  LOVING  CUP. 

(Continued  from  page  107) 
the  good  times  they  used  to  have  while 
working-  on  the  several  relays  which  we 
have  run  for  their  benefit. 

Next  month  we  will  start  by  giving  some 
gossip  about  the  famous  Washington's 
Birthday  Relay,  and  also  give  the  first  in- 
stallment of  a  complete  set  of  instructions 
about  how  to  make  a  Hall  Wireless  Relay, 
as  this  instrument  was  shown  in  this  maga- 
zine some  time  ago,  under  the  list  of  pat- 
ents issued ;  and  as  the  writer  has  received 
a  great  number  of  inquiries  concerning  it, 
we  believe  that  you  will  all  be  interested 
in  reading  about  this  instrument,  which  is 
very  simple  in  construction,  and  which  all 
of  you  may  make,  with  just  such  tools  and 
material  as  is  always  at  hand  in  a  radio 
laboratory. 

The  war  will  not  last  forever,  Ama- 
teurs. Now  is  the  time  to  make  efficient 
instruments  to  be  used  after  the  war  and 
to  "brush  up"  on  all  Radio  Matters. 

DO  YOU 

own  a  wireless  station,  either  for 
sending  or  receiving?  If  you  do, 
don't  fail  to  join  the  greatest  Wire- 
less Association  in  the  country: 
THE  RADIO  LEAGUE  OF 
AMERICA.  If  you  believe  in  the 
preparedness  of  your  country,  if  you 
wish  to  help  Uncle  Sam,  if  you  wish  to  have  your  station 
officially  recognized,  join  the  LEAGUE,  a  national, 
non-money-making  organization.  Beautiful  engraved 
and  sealed  certificate,  FREE  to  all  members.  NO 
DUES  OR  FEES  WHATSOEVER. 

Honorary  Members:  W.  H.  G.  BUL- 
LARD,  U.  S.  N.;  PROF.  REGINALD  A. 
FESSENDEN;  DR.  LEE  DE  FOREST; 
DR.  NICOLA  TESLA. 

Send  stamp  for  large  8-page  information  booklet. 
DO  IT  NOW.  233FULTON  STREET,  NEW  YORK 

Continuation  of  List  of  "Perfect  Score" 
Stations  in  Trans-continental  Amateur 
Relay  as  publisht  in  the  May  number. 

OHIO 

D.  Schellenbaeh,  8  IF,  Wvoming 
R.  A.  Duerk,  8  AHI,  Defiance 
C.  Linxweiler,  8  LJ,  Davton 
(No  Name),  8  ATG,  Tiffin 
C.  Candler,  8  NH,  St.  Mary's 
L.  Berman,  8  ML,  Cincinnati 
Scott  High  School.  8  ZL,  Toledo 
Merle  Sager.  8  ASW,  Tiffin 
N.  Thomas,  8  FX,  Marietta 
M.  B.  West,  8  AEZ,  Lima 
J.  F.  Eckel,  8  PL,  Cincinnati 
J.  O.  Hibbett,  1113,  Ottawa 
L.  M.  Clausing,  8  YL,  Lima 

OKLAHOMA 
A.  &  M.  Steddon,  5  AB,  Oklahoma  City 

PENNSYLVANIA 
H.  T.  Mapes,  3  AUC,  Carlisle 
Chris.  M.  Bowman,  3  PC,  Lancaster 
High  School  Station,  8  JS,  Bellefonte 
L.  &  H.  Alexander,  8  ALE,  Grove  City 
R.  R.  Goodwin,  No  call,  Roulette 
M.  H.  Mandelkern.  3  MR,  Philadelphia 
Peabodv  High  School,  8  YZ,  Pittsburgh 
W.  &  S.  Shoop,  RS,  Vandergrift 
F.  J.  Anderson,  3  QD,  Reading 
F.  H.  Brian,  Smithport 
C.  H.  Stewart,  3  ZS,  St.  David's 
Nassau  Bros.,  3  CT,  Philadelphia 
Karl  E.  Hassel,  Oper.,  8  YI,  Pittsburgh 
R.  C.  Clement,  8  AJT,  Washington 
St.  Joseph's  College,  3  XJ,  Philadelphia 

RHODE  ISLAND 
C.  E.  Davis,  No  call,  Fdgewood 
M.  V.  Pollys,  Jr.,  1  EMG,  Bristol 
H.  W.  Thornley,  1  AI,  Pawtucket 

TENNESSEE 
S.  H.  Sheib,  5  CY,  Nashville 
C.  P..  Delahunt,  5  ZD,  Memphis 


TEXAS 

B.  Emerson,  5  DU,  Dallas 
R.  Corlett,  5  ZC,  Dallas 

J.  L.  Antry,  3  ED,  Houston 

C.  W.  Gillillan,  FM,  Austin 

VIRGINIA 
R.  R.  Chappell,  3  St,  Richmond 

G.  C.  Robinson,  3  St,  Richmond 
I.  F.  Wohford,  3  WF,  Roanoke 
W.  T.  Gravely,  3  RO,  Danville 

J.  E.  Krone,  3  TY,  Newport  News 
A.  N.  Johnson,  3  TY,  Newport  News 

WEST  VIRGINIA 
J.  E.  Law,  No  call,  Clarksburg 

H.  E.  Burns,  8  AGH,  Martinsburg 

WISCONSIN 
H.  T.  Crawford,  9  WT,  Wausau 
C.  Quinn,  9  ARD,  Neenah 
M.  P.  Hanson,  9  XM,  Madison 
E.  H.  Hartnell,  9  BV,  Salem 
A.  Rufsvold,  9  ADI,  Marinette 
O.  R.  Terry.  9  HQ,  Stoughton 


TO  RECHARGE  THIS  CELL— FILL 
WITH  WATER. 

The  "H^O"  Cell,  as  it  is  termed  by  its 
English  sponsors,  was  introduced  to  meet 


New   English   Type   of   Primary  Cell 
Which  Is  Recharged  by  Simply  Filling 
It  With  Water.    It  Is  Known  As  the 
"H,.0"  Cell. 


the  demand  for  a  wet  cell  smaller  and  more 
compact  than  the  "Leclanche,"  and  in  this 
respect  it  appears  to  have  gained  its  ad- 
vantage. This  cell  may  be  stored  for  any 
length  of  time  and  in  any  climate  without 
any  deterioration.  It  is  not  liable  to  creep- 
ing or  evaporation  while  in  use.  Its  inter- 
nal resistance  is  low,  and  it  does  not  polar- 
ize in  use  so  quickly  as  wet  batteries  of  the 
"Leclanche"  type,  it  is  claimed. 

The  addition  of  water  only  is  needed  for 
charging,  and  its  active  life  is  equal  to  any 
high-grade  cell  of  similar  size.  If  the  cell  is 
required  for  instant  use,  it  is  recommended 
that  the  cell  be  filled  with  warm  water  ;  dis- 
tilled water  being  used,  if  possible,  as  this 
tends  to  prolong  the  life  of  the  cell  by  rea- 
son of  the  absence  of  iron  or  lime  impur- 
ities, which  are  frequently  found  in  hydrant 
water. 

In  order  that  the  condition  of  the  zinc 
electrode  and  the  interior  parts  of  the  cell 
may  be  examined,  the  container  consists  of 


RS 


TO 

1  GREAT 
OPPORTUNITY! 

We  liavo  the  following  listed  motors  in 
stock.  We  are  discontinuing  these  sizes 
offer  them  now  BELOW  COST.  If  you  need  a 
good,  brand  new  motor  that  is  just  a  little  shop  worn 
from  handling,  in  our  stock  rooms,  this  is  your  chance. 
These  are  all  for  110  volts  direct  current.  Further 
particulars  may  be  had  by  applying  to  the  undersigned. 
3— 1/4H.P.  D.  C,  110  volts,  each  $19.00:  list  price, 
$24.00.  3—  leH.P.,  D.  C,  110  volts,  each  $9.00:  list 
price.  $15.00.  I— '/2H.P..  D.  C,  110  volts,  each  $37.00: 
list  price,  $46.50.  I  — I/I6H.P.,  D.  C,  110  volts,  each 
$7.00:  list  price.  $9.00. 


Loo 


Electro  Importing  Co* 

J£  231  FultonSt.,  New  York  City,  N.  Y. 


4I4'„PA  CES 

&5  ILLUSTRATIONS 


ELECTRICITY! 

HERE'S  just  the  book  on 
Electricity  that  you  need 
to  answer  your  many  ques- 
tions—to solve  your  knotty 
problems,  to  teach  you  new  kinks,  to 
be  your  memory  for  tables,  rules, 
formulas  and  other  Electrical  and 
Mechanical  facts  that  some  people  try 
to  carry  in  their  heads — and  fail. 

With  this  "Little  Giant"  I.  C.  S.  Elec- 
trical Engineer's  Handbook  in  your 
pocket,  tool  chest,  on  your  work 
bench, drawingtable ordesk,  an  hour 
or  a  day  need  not  be  lost  "digging 
up"  some  forgotten  rule,  some  unfamiliar  fact; 
you'll  just  turn  to  the  very  complete  index  and 
get  it  in  a  jiffy."  Just  a  few  of  the  subjects 
treated  are: 

Electricity  and  Magnetism ;  Electrical  Symbols ; 
Batteries;  Circuits;  Magnets;  Direct  and  Al- 
ternating Currents;  Dynamos  and  Motors; 
Belts;  Shafting;  Electroplating;  Electrical 
Measurements;  Meters;  Arc  and  Incandes- 
cent Lamps;  Mercury  Arc  Rectifiers;  Trans- 
formers; Insulation;  Electric  Cars;  Single  and 
Multiple-Unit  Control;  Transmission;  Rail 
Welding;  Tables  of  Wires — Sizes,  Capacities, 
etc., — Mathematical  Rules,  Formulas,  Sym- 
bols; Tables  of  Constants,  Equivalents,  Roots, 
Powers,  Reciprocals,  Areas,  Weights  and 
Measures;  Chemistry;  Properties  of  Metals; 
Principles  of  Mechanics:  First  Aid,  etc. 

The  Electrical  Engineer's  Handbook  is  one  of  22 
I.  C.  S.  Handbooks  covering  22  Technical,  Scien- 
tific and  Commercial  subjects,  all  crowded  with 
value.  They  have  the  contents  of  a  full-size  book 
condensed  into  pocket-size  ready  to  go  with  you 
anywhere  and  be  at  your  instant  command. 
They  are  substantially  bound  in  cloth,  red  edges, 
goldleaf  stamping,  printed  from  new,  clear,  read- 
able type  on  good  quality  book  paper.  There  is 
an  illustration  at  every  point  where  a  picture 
will  help.  Hundreds  of  thousands  have  been 
sold  on  a  money-back  guarantee  of  satisfaction. 


The  regular  price  is  $  1 .25,  but  for  a  LIMITED 
TIME  you  can  buy  the  ones  you  want,  post- 
paid, delivery  guaranteed,  for  only  50  cents. 


You  Run  No  Risk!   Money  Back  if  Desired  f 

International  Correspondence  Schools 

Box    ,5349,  Scran  [on.  Pa. 


INTERNATIONAL  CORRESPONDENCE  SCHOOLS 

Box    53  49,  SCRANTON,  PA. 

I  enclose  $  for  which  send  me  postpaid  the 

Handbooks  marked  X,  at  50c.  each.  I  may  return  any  or  all 
and  get  my  money  back  within  ten  days  trom  receipt: 


Q  Electrical  Engineer's 

□  Teleph.aod  Teleg.  fcuglnt 

□  Mechanic's 

□  Steam  Engineer's 

□  Westinghouse  Air  Bra 

□  Civil  Engineer's 

□  Coal  Miner's 

□  Concrete  Engineer's 

□  Building  Trades 

□  Plumbers  and  Fitter's 
Q  Chemist's 

Name   


Street 
and  No. 


□  Advertiser's 

□  Business  Man's 
O  Bookkeeper's 

□  ■Steiio.  anil  Correspondent's 

□  Salesman's 

Q  Window  Trimmer's 

O  Cotton  Textile  Worker's 

D  Farmer's 

Q  Poultry  man's 

□  Mariner's 

□  Automobile 


I  City_ 


You  benefit  by  mentioning  "The  Electrical  Experimenter"  when  writing  to  advertisers. 


144 


THE   ELECTRICAL  EXPERIMENTER 


June,  1917 


AMATEURS! 

MOW  is  the  time  to  overhaul  your  set  and 
to  buy  your  apparatus  at  a  low  cost. 

Remember,  the  War  won't  last  forever,  and 
when  the  ether  is  free  once  more  for  all,  YOU 
want  to  be  the  first  one  to  listen  in  with  a 
REAL  set. 

Besides,  there  is  the  possibility  that  the  Govern- 
ment will  soon  again  allow  us  to  operate  receiv- 
ing sets  during  the  War. 

Are  you  ready  ? 

Write  for  our  printed  matter. 
AudioTron  Sales  Co.,  315  Lick  Bldg.,  San  Francisco,  Cal. 


KMM-SSMM  MM  MSI.zniMZnijrjiM.zr^ 


A  Motor  and  a  Rotor  for  $5.25 

We  have  built  5000  of  these  outfits,  consisting  of  a  motor 
that  will  operate  on  a.  c.  or  d.  c,  5000  to  6000  r.  p.  m.,  100 

to  130  volts. 

An  aluminum  rotor,  per- 
fectly  balanced,  machined 
and  insulated. 

$4.00 

Motor  only 

$1.50 

Rotor  only 


Regular  price  of 
these  outfits,  $8.50 

Introductory  offer 
as  above,  while 
they  last.  Act 
quick. 


When  ordering  rotors  give  size  of  shaft 


One-half  actual  size 


The  Fosco  Corporation 

1355  N.  Western  Ave.,  Chicago,  III. 

Send  postage  for  catalogue  of  motors  and  supplies 


"THERE'S  MONEY  IN  IT"    _ 

HS^  LEARN  TELEGRAPHYfi^ 

„_L-MORSE  AND  WIRELESS-".— 


TEACH  YOURSELF 


in  half  the  usual  time,  at  trifling  cost,  with  the 
wonderful  Automatic  Transmitter,  THE  0MNIGRAPH. 

Sends  unlimited  Morse  or  Continental  messages,  at 
any  speed,  just  as  an  expert  operator  would. 

Adopted  by  U.  S.  Gov't.    4  styles.    Catalogue  free. 

OMNICRAPH  MFC.  CO. 

39L  Cortlandt  St.  New  York 


a  clear  glass  jar,  A.  (See  diagram.)  Into 
the  bottom  of  this  jar  some  bitumen  is 
poured  while  in  a  hot  condition.  This 
serves  to  fix  the  porcelain  base,  B,  in  posi- 
tion. This  base  forms  the  support  for  the 
sack,  C,  keeping  it  in  a  central  position,  and 
also  a  support  and  spacer  for  the  zinc  cylin- 
der, D,  keeping  it  always  the  correct  dis- 
tance from  the  sack.  It  is  this  narrow 
space  between  the  zinc  and  the  sack  which, 
to  a  large  extent,  makes  the  internal  resist- 
ance of  these  cells  so  much  less  than  Le- 
chanche  batteries.  The  top  of  the  sack  has 
a  rubber  ring,  E,  round  it  in  order  to 
further  safeguard  against  the  zinc  cylinder 
touching  the  sack.  Above  the  sack  a  spe- 
cially shaped  porcelain  ring,  F,  is  slipt  over 
the  carbon  rod,  G,  and  this  serves  as  a  sup- 
port for  a  waxt  cardboard  disk,  H,  which 
supports  the  sealing  compound.  Two  holes 
are  arranged  in  the  sealing  compound  and 
the  cardboard  washer ;  in  one  of  these  is  a 
fiber  tube.  This  tube  forms  the  funnel 
thru  which  the  water  is  poured  when  the 
cell  is  required  for  use,  and  is  normally 
sealed  with  a  cork.  The  other  hole  con- 
tains a  small  glass  tube  to  allow  the  gases 
generated  when  the  cell  is  in  action  to 
escape.  A  lead  connection  strip,  J,  is  sol- 
dered to  the  zinc  cylinder,  and  this  is 
brought  up  at  the  side  of  the  cardboard 
washer  and  thru  the  sealing  compound. 
This  lead  strip  is  provided  with  a  punched 
hole  to  allow  of  connection  to  an  adjacent 
battery.  A  brass  cap,  K,  is  forced  on  to 
the  carbon  rod,  and  the  nut  for  wire  con- 
nections screws  on  to  a  pin  riveted  and 
soldered  to  the  cap.  The  ammonium  chlo- 
rid  crystals,  L,  are  placed  in  the  cell  at  the 
time  of  manufacture ;  so  that  all  that  is 
necessary  to  make  the  cell  ready  for  use 
is  to  remove  the  cork,  fill  the  cell  with 
water,  and  replace  the  cork. 


POWERFUL  HYDRO-ELECTRIC 
SALVAGE  APPARATUS  TO 
RAISE  SUNKEN  SHIPS. 

{Continued  from  page  95) 
may  have  gone  ashore  in  shoal  waters. 
Supposing  that  a  vessel  has  become  em- 
bedded in  the  sand.  Upon  arriving  at  the 
scene  with  one  of  the  Linquist  hydrostatic 
lifting  units  of  the  type  already  described, 
this  is  set  up  out  in  the  deep  water  at  a  con- 
siderable distance,  say  one  thousand  to 
1,500  feet  from  the  vessel  in  distress,  and 
a  heavy  cable  is  attached  to  the  oceanward 
side  of  the  vessel.  In  certain  cases,  and 
when  necessary  a  line  may  be  shot  over  the 
vessel  to  carry  out  this  part  of  the  opera- 
tion. The  cable  which  is  secured  to  the 
stranded  vessel  is  carried  from  the  Lin- 
quist apparatus,  and  passes  thru  two  large 
pulleys  secured  to  a  stationary  truss  on  the 
base  of  the  "fort,"  and  in  proximity  to  the 
vertical  member  of  the  lifting  apparatus. 
The  free  end  of  the  catile  is  secured  to 
the  top  of  the  telescopic  movable  cylinder 
of  the  Linquist  device,  and  this  is  made  to 
rise  by  becoming  more  buoyant  thru  the 
agency  of  the  electric  pumps  (supplied 
with  electric  power  from  the  lines  on  shore), 
water  being  pumped  out  of  the  movable 
telescopic  cylinder  causing  it  to  rise,  and 
when  this  occurs  a  force  of  thousands  of 
tons  is  brought  into  play,  giving  sufficient 
upward  pull  on  the  cable  passing  thru  the 
stationary  pulleys  to  haul  the  vessel  off  the 
shoal. 

The  inventor  of  this  truly  remarkable 
scheme  for  raising  sunken  boats,  etc.,  says 
that  if  his  device  had  been  available  at  the 
time  the  U.  S.  Submarine  F-4  sunk  in  the 
Honolulu  harbor  some  time  ago,  that  he 
could  have  raised  the  submarine  in  four 
days  instead  of  taking  four  months,  which 
was  the  time  required  by  the  only  method 
available,    when   this    deplorable  accident 


You  benefit  by  mentioning  "The  Electrical  Experimenter"  when  -writing  to  advertisers. 


June,  1917 


THE   ELECTRICAL  EXPERIMENTER 


145 


occurred.  One  of  the  divers  who  worked 
on  the  Submarine  F-4  and  who  had  nego- 
tiated depths  of  306  feet  (corresponding  to 
a  pressure  of  135  pounds  to  the  square  inch) 
has  seen  the  device  and  believes  that  Mr. 
Linquist's  calculations  as  just  cited  are  not 
only  practical  but  feasible. 


ELECTRICITY  AND  WATER  TO 
RUN  OUR  AUTOS. 

(Continued  from  page  88) 

and  air  will  eliminate  all  carbon  deposits, 
and  in  so  doing  will  add  to  the  life  and 
power  of  any  motor,  and  that  is  not  all,  for 
we  obtain  our  gas  from  water,  which  nature 
has  provided  abundantly,  and  so  easy  to  se- 
cure that  the  cost  is  practically  nothing. 

Those  interested  in  this  electrolytic  cell 
gas  generator  intended  for  a  substitute  for 
gasoline  in  driving  automobiles  will  un- 
doubtedly find  interesting  a  U.  S.  patent  on 
a  similar  cell,  bearing  the  number  1,219,966 
which  is  discust  in  the  "Latest  Patents" 
department  on  page  128  of  this  issue. 


DECISION  IN  THE  "HETERO- 
DYNE" RADIO  RECEIVER 
CASE. 

On  April  2  Judge  Mayer,  of  the  United 
States  District  Court  for  the  Southern 
District  of  New  York,  handed  down  an 
opinion  in  the  suit  of  Samuel  M.  Kintner 
and  Halsey  M.  Barrett,  receivers  of  the 
National  Electric  Signaling  Company, 
plaintiffs,  vs.  the  Atlantic  Communication 
Company,  August  Merckens,  P.  C.  Schnitz- 
ler  and  K.  G.  Frank,  defendants,  in  which 
he  found  for  the  plaintiffs.  This  suit  was 
based  upon  a  charge  of  infringement  of 
United  States  letters  patent  1,050,728  and 
1,050,441,  being  respectively  for  the  method 
and  apparatus  employed  in  a  receiving  sta- 
tion of  a  radio  telegraph  system.  These 
patents,  issued  January  14,  1913,  cover  the 
invention  known  to  the  art  generally  as 
the  "heterodyne"  or  beats  method  of  re- 
ceiving radio  telegraph  signals. 

The  court  found  that  Reginald  A.  Fes- 
senden,  the  inventor  of  this  system,  had 
produced  an  invention  of  great  merit  and 
entitled  to  a  broad  interpretation.  He 
found  that  the  prior  art  cited  by  the  de- 
fendant as  anticipating  the  Fessenden  in- 
vention had  failed  to  teach  the  art  anything 
in  respect  to  the  use  of  beats  and,  at  most, 
merely  disclosed  a  local  source  for  oper- 
ating some  particular  form  of  receiver. 
He  decided  against  the  defendants'  conten- 
tion that  the  invention  should  be  given  a 
narrow  construction,  in  view  of  an  earlier 
patent  of  Fessenden. 

The  defendants'  sole  effort  was  directed 
towards  securing  a  narrow  construction  of 
the  patents.  They  contended  that  the  Fes- 
senden patents  were  not  entitled  to  a  broad 
interpretation  but  should  be  restricted  to 
the  use  of  the  particular  form  of  appli- 
ance shown  in  the  issued  patents.  The 
court  decided  against  this,  holding  the  in- 
vention to  be  of  such  merit  as  to  entitle 
it  to  a  broad  interpretation  of  equivalents. 

The  court  also  stated  that  Fessenden  or 
his  company,  the  National  Electric  Signal- 
ing Company,  were  the  only  ones  to  teach 
the  art  anything  of  value  of  this  method 
of  operation  between  the  date  of  appli- 
cation of  his  original  patent  in  1902  and 
the  date  of  applications  for  the  patents 
in  suit,  1905.  i 


A  COMPACT  FARM  LIGHTING 
PLANT. 

The  farm  lighting  plant  illustrated  is 
rated  at  1,000  watts  and  operates  at  30  volts. 
In  most  cases  a  2,  2l/2  or  at  most  a  4-h.p. 
engine  is  required  to  run  this  system.  The 
generator  has  a  heavy  flywheel  pulley  with 
tapered  shaft. 

A  feature  of  this  equipment  is  that  re- 
gardless of  variation  in  the  number  of 
lights  being  used,  the  generator  will  auto- 
matically furnish  the  current  necessary  for 
these  lights,  in  addition  to  that  which  it  has 
already  been  furnishing  for  charging  the 
battery,  thus  allowing  the  battery  to  receive 
its  normal  charging  rate  automatically,  re- 
gardless of  the  number  of  lights  being 
turned  on  and  off.  An  automatic  electric 
governing  winding  is  incorporated  in  the 
design  which  prevents  the  variation  in  the 
lighting  load  from  affecting  the  amount  of 
current  going  into  the  battery.  Lights  may 
be  used  at  any  time  either  direct  from  the 
generator,  if  the  engine  is  running,  or  di- 
rect from  the  battery,  if  the  engine  is  not 
running. 

The  manufacturer  also  claims  that  by 
using  this  self-regulating  winding  for  start- 


A   New  Compact  Electric  Generating 
Plant  Having  the  Switch-board  Mount- 
ed Rigidly  on  the  Dynamo  Frame. 


To  overcome  the  difficulties  of  navigation 
in  the  Kara  Sea  the  Russian  Government 
has  established  three  wireless  stations  that 
inform  vessels  of  ice  conditions. 


ing  duty,  engines,  regardless  of  their  type, 
can  be  started  without  abnormal  strain  on 
the  battery  plates.  This  condition  applies 
specifically  to  engines  of  8  h.p.  or  less. 
Twice  the  starting  torque  with  one-half  the 
current  is  said  to  be  produced  by  means  of 
this  winding.  In  a  test  recently  made,  this 
unit,  with  an  80-ampere  current,  easily 
started  a  4-h.p.  special  electric  engine.  A 
shunt  wound  generator  failed  to  start  the 
same  engine  with  the  ammeter  reading  140 
amperes.  This  plant  permits  the  lights  to 
burn  at  practically  the  same  brilliancy  at 
all  times.  If  the  lights  are  being  used  direct 
from  the  generator  and  should  the  engine 
stop,  the  electrical  connections  will  be 
changed  automatically,  so  that  the  lights  will 
then  receive  their  energy  from  the  storage 
battery.  The  switchboard  is  equipt  with 
large  scale  instruments,  an  automatic  re- 
verse current  circuit  breaker  and  only  one 
lighting  switch.  All  internal  connections 
are  made  at  the  factory.  The  batteries  used 
with  this  plant  are  made  in  both  the  Faure 
and  Plante  types,  assembled  in  either  rubber 
or  glass  jars. 


Mesco  Wireless  Practice  Set 

For  Learning  the  Wireless  Code 


The  Practice  Set  comprises  a  regular  tele- 
graph key,  without  circuit  breaker,  a  special 
high  pitch  buzzer,  one  cell  Red  Seal  Dry 
Battery,  and  four  feet  of  green  silk  covered 
flexible  cord. 

The  key  and  buzzer  are  mounted  on  a 
highly  finished  wood  base,  and  three  nickel 
plated  binding  posts  are  so  connected  that 
the  set  may  be  used  for  five  different  pur- 
poses, as  illustrated  on  page  24. 

For  the  beginner,  the  set  is  of  exceptional 
value,  for  it  may  be  used  for  individual  code 
practice  or  for  operation  of  a  two  party  line, 
which  is  an  excellent  method  of  quickly 
learning  the  code.  After  the  beginner  has 
mastered  the  code,  the  set  may  be  used  in 
his  wireless  outfit  for  setting  the  detector 
in  adjustment,  and  also  the  key  may  be  used 
to  control  the  spark  coil. 

Recommended  for  schools,  as  it  gives  ex- 
cellent service  for  class  instruction  in  code 
work.     Full  directions  with  each  set. 

The  main  object  of  the  set  is  to  enable  the 
beginner  to  master  the  wireless  code,  and 
the  buzzer  reproduces  the  sound  of  the  sig- 
nals of  the  most  modern  wireless  stations 
perfectly. 

Every  beginner  needs  one  of  these  sets, 
and  as  it  is  the  equivalent  of  five  different 
sets,  the  price  is  very  low. 

List  No.  Price. 

342.    Wireless  Practice  Set,  with  Battery 

and  Cord   $2.25 

344.  Wireless  Practice  Set  only,  no  bat- 
tery or  Cord   :   2.00 

Send  for  Our  New  Edition  of  our 
Catalog  W28  Ready  June  15 

It  Is  pocket  size,  contains  248  pages,  with  over  1.000 
illustrations  and  describes  In  plain,  clear  language 
all  about  Bells,  Push  Buttons.  Batteries,  Telephone 
and  Telegraph  Material,  Electric  Toys.  Burglar  and 
Fire  Alarm  Contrivances.  Electric  Call  Bells,  Electric 
Alarm  Clocks.  Medical  Batteries,  Motor  Boat  Horns, 
Electrically  Heated  Apparatus,  Battery  Connectors, 
Switches,  Battery  Gauges.  Wireless  Telegraph  In- 
struments, Ignition  Supplies,  etc. 

IT  MEANS  MONEY  SAVED  TO  YOU 

to  have  our  Catalog  when  you  want  to  buy. 

Manhattan  Electrical 
Supply  Co.,  Inc. 


New  York:  Chicago:  ST.  LOUIS: 

17  Park  Place         114  S.  5th  Ave.  1106  Pine  St. 

San  Francisco  Office:  604  Mission  St. 


Learn  Watchwork,  Jewelrywork  and 

FnffravinO  ^  ^ne  trai^e  commanding  a  good  sal- 
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WANTED— Railway  Mail  Clerks 

COMMENCE  $75  MONTH  INCREASE  TO  S150  MONTH 

Common  education 

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Sure  pay.  _f  Franklin  Institute 

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Pullunnec-  girB_  Send  me  without  charf,ei 

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f.O  big  paid   government  jobs    now  easily 

*  obtainable  and  free  book  describing  them. 

Name  ,  

A  ddress  


146 


THE  ELECTRICAL  EXPERIMENTER 


June,  1917 


CONSTANT  AMPLITUDE 
TEST  BUZZER 


Dimensions  2Vi"x2V2"  Price,  $1.20 

Postage  10  cents 

OVER  1200  SOLD 

Our  special  Constant  Amplitude  Test 
Buzzer  contains  some  entirely  new  features 
and  closely  resembles  the  tone  of  a  500- 
cycle  Telefunken  set.  This  is  due  to  the 
arrangement  of  the  contact  which  is  pro- 
vided with  a  lenient  back-check  which  pre- 
vents the  armature  from  overreaching  and 
the  amplitude  becomes  constant.  This  you 
will  find  in  no  other  Buzzer.  The  contact 
points  are  of  pure  silver  which  prevents 
burning  and  the  entire  mechanism  is  en- 
closed in  a  non-resonant  dielectric  case. 
You  will  never  know  you  have  a  Buzzer  in 
your  circuit  as  far  as  attention  is  con- 
cerned. It  is  provided  with  three  binding 
posts  and  is  highly  finished. 

EUGENE  T.  TURNEY  CO.,  Inc. 

2595  Third  Avenue,    New  York  City 


ENCLOSED 
ROTARY  OAP 

This  gap  has  been  designed 
to  sell  at  a  low  price  and  to 
meet  the  demands  of  ama- 
teurs for  a  good,  enclosed 
and  silent  gap.  Finished  in 
dull  black,  it  will  add  to  the 
appearance  of  your  set. 
It  is  made  inonestyleonly, 
for  all  powers  up  to  I-KW, 
and  can  be  mounted  in  al- 
most any  position. 
The  gap  is  enclosed  in  a 
circular  iron  housing  8  inches 
in  diameter  and  7XA  inches 
thick,  with  removable  cover 
(for  inspection).  The  adjust- 
ment can  be  as  close  as  desired 
between  sparking  points. 
Rotating  disc  is  of  brass  with  12  projecting 
round  brass  arms  (total  diameter  6  inches), 
mounted  on  shaft  running  in  bronze  bearing 
and  is  belt  driven  by  small  motor  giving  a 
variety  of  tones  depending  upon  the  speed. 

When  in  operation  this  gap  is  very  quiet 
Price  complete,  without  motor,  $8,50 
J.  Herbert  Ferris,  Zll  Catalpa  Drive,  Royal  Oak,  Mich. 


SPARK  COILS  i^wircicss 


1 


COIL 


$3.50 


STYLE  C  SPECIAL 
Postage  extra 

FINE  RESULTS  WITH  THIS  COIL 

SCHUG  ELECTRIC  MFG.  CO. 

254  EAST  LARNED,  DETROIT,  MICH. 


Distributed  a9*a  supplement  to  our  big  Handv  Book 
during  temporary  government  suspension  of  wire- 
less. Lists  new  things  to  experiment  with.  Also 
motors,  flashlights,  telegraph  apparatus,  puzzles, 
magic  outfits,  books,  athletic  goods,  chemical  seta, 
fishing  tackle,  novelties.  Handy,  interesting.  For 
every  boy  in  America.   Free  on  Request. 

The  Electro-Set  Co.,  nowjcnnwn  as 
The  Newman-Stem  Co.,      Dept.  E  IS,      Cleveland,  Ohio 


POCKET  BOOK  °f  ELECTRICITY 


SPECIAL  WAR  EDITION  11:1 4  J 


SHIPS  WHICH  THE  RADIO  SAVED. 

The  U.S.  Government  cites  the  follow- 
ing marine  disasters  in  which  wireless  fig- 
ured during  the  period  July  1  to  Decem- 
ber 31,  1916: 

July  11. — Steamship  Ramos  foundered  in 
a  gale  while  en  route  from  Philadelphia  to 
Cartagena,  Colombia.  SOS  calls  were  an- 
swered by  the  Miami  land  station  and  the 
steamships  Van  Hogendorp  and  Illinois,  all 
but  five  persons  on  board  being  saved. 

July  22. — Steamship  Matatna,  stranded 
on  rocks  seven  miles  south  of  St.  Mary's 
Light,  Cape  Race.  Vessel  shot  line  to 
shore  and  passengers  and  crew  were  re- 
moved. The  distress  call  was  answered  by 
the  steamship  Stephano,  Red  Cross  Line, 
which  stood  by  until  passengers  were  safe- 
ly removed. 

September  15.  —  Steamship  Congress, 
with  445  persons  on  board,  caught  fire  off 
Coos  Bay,  Marshfield,  Oreg.  The  vessel 
was  headed  toward  shore.  SOS  calls  be- 
ing sent  out  continuously,  which  were  re- 
ceived by  the  land  stations  at  Marshfield, 
Oreg.,  Cape  Blanco,  Oreg.,  and  Eureka, 
Cal.,  and  the  steamship  F.  A.  Kilbum.  Res- 
cue vessels  were  dispatched  by  the  Marsh- 
field station,  and  all  persons  on  board  were 
saved. 

September  23. — Steamship  Bay  State  ran 
ashore  off  Cape  Elizabeth,  Me. ;  total  loss. 
Distress  calls  were  answered  by  the  Coast 
Guard  cutter  Ossipee  and  the  naval  station 
at  Cape  Elizabeth,  which  dispatched  the 
tugs  Portland  and  Cumberland.  All  per- 
sons on  board,  approximately  200  in  num- 
ber, were  saved. 

October  7. — Steamship  Ant  ilia,  with  fifty- 
six  persons  aboard,  caught  fire  off  the  Vir- 
ginia Capes  while  en  route  from  Guanta- 
namo,  Cuba,  to  Xew  York.  Approximately 
twenty-five  vessels  responded  to  the  dis- 
tress calls,  and  all  persons  were  saved. 

October  19. — Steamship  A  rap  hoe  lost 
her  rudder  twenty-five  miles  north  of  Cape 
Lookout.  SOS  calls  were  answered  by  the 
steamship  Henry  R.  Mallory  and  the  Coast 
Guard  cutters  Seminole  and  Tampa,  which 
towed  the  vessel  to  Norfolk. 

October  28. — Steamship  Chicago,  with 
265  passengers  and  crew,  caught  fire  at  sea 
and  arrived  safely  at  the  Azores  Islands. 
Communication  was  established  with  ves- 
sels, but  assistance  was  not  needed. 

October  29. — Tug  Vigilant  disabled  150 
miles  off  Irish  coast.  SOS  call  answered 
by  the  steamship  Ryndam,  which  towed  the 
tug  to  Queenstown. 

November  25. — Steamship  Powhatan,  en 
route  from  Boston  to  Baltimore,  cauglit  fire 
off  Block  Island.  Fire  was  controlled  be- 
fore arrival  of  Coast  Guard  cutters,  which 
answered  the  distress  call. 

November  27. — Steamship  Niels  Nielson 
lost  propeller  in  heavy  gale.  Distress  calls 
were  answered  by  several  vessels,  which 
assisted  the  disabled  vessel  to  make  port. 

November  28. — Steamship  Coronado  lost 
propeller  off  Tillamook  Head.  Distress 
calls  answered  by  Astoria,  Oreg.,  station, 
which  dispatched  tug  to  assistance  of  dis- 
abled vessel. 

December  3. — Steamship  Carolina,  Good- 
rich Transit  Co.,  struck  rocks  off  entrance 
to  Sturgeon  Bay  Canal.  Distress  calls  were 
received  by  the  Manitowoc,  Wis.,  station, 
which  dispatched  a  tug  to  the  assistance  of 
the  disabled  vessel. 

December  12. — S  t  e  a  m  s  h  i  p  Sumner 
grounded  in  fog  off  Barnegat,  N.J.  Six  ves- 
sels responded  to  SOS  calls,  and  all  per- 
sons on  board  were  saved. 

December  14. — Steamship  Powhatan,  en 
route  from  Norfolk  to  Boston,  sank  in  col- 
lision with  unknown  vessel  on  way  to  open 
sea.  Several  United  States  destroyers, 
Coast  Guard  cutters,  and  steamship  James- 


DO  YOU? 

By  Albert  W.  Wilsdon. 

RECENTLY  I  bought  a  copy  of  the 
ELECTRICAL  EXPERIMENTER 
AND  I  read  it  through 
DURING  the  time 

THAT  I 

HAD  to  spare 

EVERY  day  that  I  could. 

EVERY  time  in 
LOOKING  thro 

ELECTRICAL  magazines  which  I  thought 

CONTAINED  news 

THAT   would  help  the 

READER  in  his  work, 

I  always  found 

CERTAIN  articles  that  were 

ALWAYS  vague  and  which 

LEFT  me  in  the  dark. 

EVER  thinking  that 
XPERIMENTERS  like  myself 
PURCHASE  magazines 
EACH  month  for  the  purpose  of 
READING  articles 
IN  which 

MANY  new  wrinkles, 
EACH  new,  and 
NOVEL,  are  to  be  found. 
TWAS  for  this  reason  that 
EVERY  month  I  now 
READ     the     ELECTRICAL  EXPERI- 
MENTER. 

THEREFORE  BE  IT  ENACTED  by 
all  experimenters  and  the  general  public, 
that  every  Experimenter  who  has  not  read 
the  ELECTRICAL  EXPERIMENTER  do 
so  at  once,  without  delay. 

THE  PENALTY  for  failure  to  do  so  is 
a  fine  of  15  or  20  cents,  which  is  paid  for 
other  magazines,  as  well  as  the  loss  of 
articles  which  cannot  be  found  or  obtained 
elsewhere. 

Apologies  to  "Casey  Bee." 

town  answered  SOS  calls.  Crew  trans- 
ferred to  Coast  Guard  vessels  and  passen- 
gers were  taken  to  New  York  on  the  steam- 
ship Jamestown. 

December  25.  — ■  Steamship  Maryland 
sank  at  sea,  position  as  given  in  SOS  call 
380  miles  east  of  Sandy  Hook,  with  crew 
of  thirty-four.  Distress  calls  answered  by 
several  Coast  Guard  cutters,  but  they  were 
unable  to  locate  the  disabled  vessel. 


750,000  HORSEPOWER  WASTED  IN 
NEW  YORK. 

Electric  power  sufficient  to  turn  every 
wheel  and  illuminate  every  dwelling  and 
factory  in  New  York  State  could  be  de- 
veloped from  the  water  power  which  is 
running  to  waste  every  day  in  the  rivers, 
streams  and  canals  of  the  State,  Attorney 
General  Woodbury  declared  in  his  annual 
report  submitted  to  the  State  Legislature. 
He  estimates  a  daily  waste  of  750,000  elec- 
tric horsepower  on  the  Long  Sault  Rapids 
and  along  the  line  of  the  barge  canal.  He 
urges  the  Legislature  to  establish  a  policy 
by  which  the  State  will  reap  some  benefit 
from  this  stupendous  resource,  the  value 
of  which  has  been  estimated  by  conserva- 
tion experts  at  $250,000,000.  Attorney  Gen- 
eral Woodbury  points  out  that  the  Long 
Sault  Rapids  in  the  St.  Lawrence  River, 
control  of  which  was  recently  regained  by 
his  office  after  a  fight  which  was  carried 
to  the  United  States  Supreme  Court,  could 
be  harnessed  to  yield  over  700,000  electric 
horsepower,  while  the  dams  and  other 
structures  along  the  course  of  the  barge 
canal  impound  an  excess  of  water  over 
navigation  requirements  sufficient  to  gen- 
erate 50,000  horsepower. 


You  benefit  by  mentioning  "The  Electrical  Experimenter"  when  writing  to  advertisers. 


June,  1917 


THE   ELECTRICAL  EXPERIMENTER 


147 


SPRAGUE  DEFENDS  ELECTRIC 
DRIVE  FOR  CRUISERS. 

After  consultation  with  Secretary  of  the 
Navy  Daniels,  Frank  J.  Sprague,  Chairman 
of  the  Naval  Consulting  Board  Committee 
on  Electricity  and  Ship  Construction,  has 
come  out  strongly  against  the  critics  of 
electrical  drive  for  the  new  battle  cruisers. 

In  a  letter  to  Senator  Swanson,  Chair- 
man of  the  Senate  Committee  on  Naval 
Affairs,  Mr.  Sprague  says  he  has  been  re- 
luctant hitherto  to  join  in  public  discus- 
sion of  the  decision  of  the  Navy  Depart- 
ment to  adopt  electric  drive. 

"I  feel  that  perhaps  I  am  now  justified 
in  so  doing,"  he  adds,  "in  view  of  the 
fact  that  such  discussion,  which  I  assumed 
was  begun  from  patriotic  motives,  seems 
to  be  taking  on  the  nature  of  an  active 
commercial  propaganda,  incidentally  sup- 
ported by  a  number  of  gentlemen,  most 
of  whom,  however  representative  and  en- 
dowed with  experience  along  the  lines  of 
their  individual  professions,  are  utterly  un- 
trained in  naval  affairs,  and  hence  are  not 
possest  of  sufficient  knowledge  of  this 
particular  subject  to  indulge  in  the  ava- 
lanche of  criticisms  which  have  been  lev- 
eled at  the  department." 

Referring  to  what  he  describes  as  "the 
successful  installation  of  the  electric  drive 
on  a  comparatively  small  scale  on  the  col- 
lier Jupiter  and  the  adoption  of  similar 
power  for  three  battleships,"  Mr.  Sprague 
reminds  Chairman  Swanson  that  "the 
Navy  Department,  reinforced  in  their  opin- 
ion by  what  had  been  done  in  electrical  de- 
velopment in  great  power  plants,  decided 
upon  electric  drive  also  for  the  battle 
cruisers,  each  of  which  is  to  be  equipt  with 
engines  of  the  large  total  of  180,000  horse- 
power. 

"The  wisdom  of  this  decision,"  Mr. 
Sprague  continues,  "was  challenged  by 
Charles  Curtis  of  the  International  Curtis 
Marine  Turbine  Company,  which  company 
would,  if  geared  turbines  were  adopted  in- 
stead of  the  electric  drive,  be  a  beneficiary 
by  a  large  amount  of  royalties.  It  is,  of 
course,  difficult  for  one  engaged  in  a  com- 
mercial enterprise  which  may  be  seriously 
affected  to  be,  even  if  unconsciously  so  un- 
affected in  his  judgment  by  personal  inter- 
ests, but  I  prefer  to  believe  that  Mr.  Curtis 
was  actuated  by  a  desire  that  our  cruisers 
should  be  the  best  afloat,  even  if  I  disagree 
somewhat  with  his  methods  and  conclusions. 

"Failing  to  get  a  reconsideration  of  the 
Navy  Department's  decision,  a  number  of 
prominent  engineers  have  been  requested  to 
write,  and  several  have  written,  letters  based 
on  certain  adverse  information  supplied 
them,  some  condemning  without  reserve  the 
decision  of  the  department  and  others  urg- 
ing that  the  matter  be  referred  to  the  Naval 
Consulting  Board  or  some  other  board  of 
civilian  engineers. 

"Among  those  other  than  Mr.  Curtis, 
who  have  been  quoted  as  authorities  are 
Dr.  S.  S.  Wheeler,  President  of  the  Crock- 
er-Wheeler Company,  manufacturers  of 
electrical  machinery,  who  has  been  vol- 
uminous in  his  criticisms ;  Dr.  Francis 
Crocker,  an  associate  of  Dr.  Wheeler; 
George  Gibbs,  Consulting  Engineer  of  the 
Pennsylvania  Railroad;  Dr.  Michael  Pup- 
in,  a  distinguished  scientist  and  inventor  of 
a  system  for  increasing  the  efficiencv  of 
the  long-distance  telephone ;  Isham  Ran- 
dolph, a  well-known  civil  and  railroad  en- 
gineer; Prof.  William  H.  Burr,  a  widely- 
known  consulting  engineer ;  President 
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148 


THE  ELECTRICAL  EXPERIMENTER 


June,  1917 


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manufacturers  of  electrical  machinery; 
Luther  Lovekin,  Chief,  Engineer  of  the 
New  York  Shipbuilding  Company,  and  Cal- 
vin Tomkins,  former  Dock  Commissioner 
of  New  York." 

Observing  that  this  list  "contains  many 
names  not  only  of  men  of  prominence  but 
of  men  standing  high  in  their  professions," 
Mr.  Sprague  says:  "But  the  question  may 
properly  be  asked  to  what  extent  are  these 
gentlemen  qualified  to  criticise,  what  is  the 
training  and  experience  which  would  war- 
rant them  to  sit  as  judges  in  so  vital  a 
matter,  and  what  is  it  they  really  seek  to 
accomplish. 

"The  discussion,"  Mr.  Sprague  contin- 
ues, "seems  first  to  seek  to  condemn  the 
adoption  of  electricity  on  the  score  of  in- 
creased weight  and  cost,  or  impossibility 
of  construction,  or  safety  in  operation,  and 
second,  a  reference  of  the  whole  matter  to 
the  Naval  Consulting  or  some  other  board. 


A  PRESENT-DAY  ELECTRIC 
GIANT. 

While  we  may  not  have  the  human  giants 
of  old  with  us,  their  places  are  admirably 


The   Largest  Self-control   Induction,  Feeder 
Voltage  Regulator  Ever  Built. 


filled  by  the  gigantic  mechanical  and  elec- 
trical apparatus  that  modern  genius  has 
evolved,  as  for  instance,  the  device  shown 
in  the  accompanying  illustration.  This  pic- 
ture shows  the  largest  self-control  induc- 
tion, feeder  voltage  regulator  that  has  ever 
been  built.  The  regulator  is  of  the  oil- 
insulated,  self-cooling  type,  and  was  built  by 
a  Pittsburgh  concern.  It  is  rated  at  600 
kva.  (kilowatts)  3-phase,  60  cycles,  13,200 
volts,  with  10  and  20  per  cent  regulation 
at  262  and  131  amperes.  It  is  designed  for 
operation  outdoors  with  full-automatic  con- 
trol self-contained. 

This  regulator  was  built  for  the  South- 
ern Power  Company  and  is  to  be  connected 
to  the  low  voltage  side  of  a  6000  kva.  (kilo- 
watt) bank  of  44,000  to  13,000  volt  trans- 
formers on  the  power  company's  line  at 
Spray,  N.  C.  By  the  use  of  this  regulator 
the  power  from  the  line  will  be  delivered 
to  the  Thread  Mill  Company  mills  owned 
by  the  Marshall-Field's  interests,  with  the 
voltage  maintained  continuously  at  normal 
value. 


"It  is  inconceivable,"  says  Mr.  Sprague, 
"that  with  all  tfie  known  facts  in  hand  the 
Navy  department  would  or  could  surrender 
to  outside  advisers,  directly  or  even  infer- 
entially,  the  selection  between  two  known 
and  accepted  methods  of  drive,  with  their 
varying  influence  upon  the  distribution  of 
weights,  'ocation  of  turrets  and  armor,  size 
and  disposition  of  compartments  and  the 
results  of  flooding,  the  distribution  of  fuel, 
the  distances  of  machinery  from  the  skin 
of  the  ship,  provision  against  torpedo 
damage,  the  necessities  of  handling  ships  in 
emergencies  and  the  results  of  failure  of 
any  parts." 

Mr.  Sprague  declares  that  generators  and 
motors  of  the  size  indicated  can  be  built, 
and  that  if  necessary  they  can  even  be  con- 
trolled by  a  push,  button  from  the  bridge. 

"I  am,"  he  says,"  "generally  credited  with 
being  the  pioneer  of  the  modern  electric 
railway  and  am  certainly  the  creator  of  that 
system  of  train  control,  now  used  the  world 
over,  which  makes  it  possible  to  aggregate 
any  amount  of  power  required  under  a 
single  control." 

One  reason  why  Mr.  Sprague  was  select- 
ed for  the  Naval  Consulting  Board  was  that 
he  had  served  as  President  of  four  techni- 
cal societies — the  American  Institute  of 
Electrical  Engineers,  the  American  Institute 
of  Consulting  Engineers,  the  New  York 
Electrical  Society  and  the  Inventors'  Guild. 


JOHN  J.  CARTY,  TELEPHONE 
ENGINEER,  NOW  MAJOR 
CARTY. 

Mr.  J.  J.  Carty,  chief  engineer  of  the 
American  Telephone  and  Telegraph  Com- 
pany, New  York  City,  and  recognized  as 
one  of  the  foremost  authorities  in  the 
world  on  wire  communication,  has  been 
commissioned  senior  major  of  the  Signal 
Officers'  Reserve  Corps,  the  reserve  auxil- 
iary of  the  Signal  Corps,  U.  S.  A.  The 
addition  of  Mr.  Carty  to  that  organiza- 
tion will  be  a  decided  accession  and  one 
which  will  be  widely  applauded.  It  is  be- 
lieved other  appointments  will  follow  from 
the  ranks  of  leading  American  engineers. 
The  importance  of  the  telephone  system  in 
any  plan  of  national  defense  has  been  ac- 
cepted by  officials  of  the  War  Department. 

The  adaptability  of  the  American  tele- 
phone lines  was  thoroly  proven  last  sum- 
mer when  the  entire  A.  T.  &  T.  Com- 
pany's service  was  turned  over  to  the  Gov- 
ernment for  a  test  under  hypothetical  war 
conditions.  In  45  seconds  Secretary  Dan- 
iels was  in  communication  with  the  Pen- 
sacola,  Fla.,  Navy  Yard,  and  in  28  sec- 
onds more  was  talking  with  the  navy  yard 
at  San  Diego.  The  Secretary  of  the  Navy 
later  exprest  his  pleasure  over  the  "won- 
derful success"  of  the  experiment.  When 
the  country's  National  Guard  was  mo- 
bilized last  summer  a  complete  telephone 
exchange  was  established  at  Camp  Whit- 
man, in  New  York  State,  in  less  than  24 
hours  after  the  troops  were  called  out, 
connecting  Washington  with  Albany,  N.  Y., 
and  all  the  vital  points  necessary  to  the 
movement.  The  commissioning  of  Mr. 
Carty  as  an  officer  in  the  Reserve  Corps 
may  be  taken  as  a  further  step  to  have 
this  important  branch  of  the  country's  de- 
fensive system  ready,  not  only  in  ma- 
terial, but  in  personnel. 


"E.  E."  WAR  NEWS  ! ! ! 

DON'T  THINK,  NOW  THAT  WE 
ARE  AT  WAR,  THAT  YOU  CAN 
DO  WITHOUT  THE  MONTHLY 
VISIT  OF  The  Electrical  Experimenter. 
KEEP  UP-TO-DATE  IN  ELEC- 
TRICITY BY  READING  IT 
"EVERY"  MONTH. 


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June,  1917 


THE  ELECTRICAL  EXPERIMENTER 


149 


Edited  by  H.  GERNSBACK 

In  this  Department  we  publish  such  matter  as  is  of  interest  to  inventors  and 
particularly  to  those  who  are  in  doubt  as  to  certain  Patent  Phases.  Regular  inquiries 
addrest  to  "Patent  Advice"  cannot  be  answered  by  mail  free  of  charge.  Such  inquiries 
are  publisht  here  for  the  benefit  of  all  readers.  If  the  idea  is  thought  to  be  of  im- 
portance, we  make  it  a  rule  not  to  divulge  details,  in  order  to  protect  the  inventor  as 
far  as  it  is  possible  to  do  so. 

Should  advice  be  desired  by  mail  a  nominal  charge  of  $1.00  is  made  for  each 
question.  Sketches  and  descriptions  must  be  clear  and  explicit.  Only  one  side  of 
sheet  should  be  written  on. 


BELL  SOFTENER. 

(152)  E.  T.  Jones,  New  Orleans.  La., 
writes  as  follows  : 

"I,  a  subscriber  to  your  wonderful  maga- 
2ine,  would  greatly  appreciate  your  opin- 
ion on  the  following  'phone-attachment, 
printing  same  in  your  Patent  Advice  de- 
partment in  one  of  the  following  issues 
this  year,  as  soon  as  possible. 

"After  reading  over  your  article  on  pat- 
ents wanted,  I  devised  a  scheme  by  which 
any  tone  desired  can  be  had  instead  of 
using  bells.  I  have  drilled  and  tapt  the 
armature  knob  of  the  ringer  and  screwed 
thereon  a  certain  device ;  on  a  protruding 
stand,  I  have  a  mandolin  string,  which  is 
adjustable  (any  note  can  be  had)  ;  when 
the  'phone  (rings)  the  device  passes  over 
the  string  and  I  have  attained  a  dull, 
soft-pitcht  tone  which  is  -audible  three 
rooms  away. 

"I  would  appreciate  your  opinion  on  the 
above  arrangement,  and  I  highly  recom- 
mend more  suggestions  on  your  part  in  a 
magazine  which  I  and  a  million  or  so 
others  cannot  do  without,  as  it  is  the  only 
live  one  out  to-day.  I  read  it  from  cover 
to  the  last  page  and  find  old  copies  inter- 
esting even  after  they  have  been  fully 
read." 

Ans.  The  idea,  while  a  very  good  one, 
does  not  seem  very  practical  for  the  rea- 
son that  the  device  would  take  up  toe 
much  room.  If  an  arrangement  were  ob- 
tained whereby  the  long  string  could  be 
done  away  with,  we  think  a  more  practical 
arrangement  would  be  had,  but  we  believe 
a  patent  can  be  obtained  on  the  idea. 


INVISIBLE  PERISCOPE. 

(153)  Jose  M.  Moreira,  Lowell,  Mass., 
submits  a  design  of  a  glass_  periscope,  his 
idea  being  to  make  it  invisible. 

Ans.  While  this  is  a  good  idea  on 
paper  it  does  not  work  out  in  practise  for 
two  reasons,  one  of  which  is  that  glass  is 
too  dangerous  a  substance  to  be  used  for 
a  periscope  which  has  to  stand  enormous 
strains  due  to  rushing  thru  the  water  as  it 
speeds  on.  Furthermore  a  periscope  stick- 
ing out  of  the  water  can  never  be  invis- 
ible, that  is,  while  the  periscope  itself  may 
not  be  seen  at  a  distance,  it  forms  a  white 
wake  as  it  runs  in  the  water,  which  is 
very  noticeable.  It  is  not  the  periscope 
itself  that  the  enemy  will  see,  but  the 
water  trail  which  the  periscope  leaves  be- 
hind. As  long  as  nothing  is  found  to  do 
away  with  this  wake,  it  is  useless  to  make 
the  periscope  itself  invisible. 


AUTOMATIC  TUBE  CLOSER. 

(154)  James  D.  Miller,  Montreal,  Que- 
bec, Canada,  submits  to  us  several  draw- 
ings of  collapsible  tubes  such  as  are  used 
with  tooth-paste  and  shaving  creams,  the 
idea  being  to  do  away  with  the  annoyance 
of  unscrewing  and  screwing  on  the  cap 
which  so  often  exasperates  us. 

Ans.    The  drawings  submitted  to  us  of 


the  device  are  very  ingenious  indeed  and 
hold  out  a  possibility  of  a  good  invention. 
We,  however,  would  advise  our  corre- 
spondent to  simplify  the  idea,  as  at  present 
it  seems  too  complicated,  having  too  many 
parts.  We  would  also  advise  our  corre- 
spondent to  submit  the  idea  to  a  patent  at- 
torney with  a  view  to  obtaining  copies  of 
prior  patents  on  this  particular  class  of 
work. 


INTERRUPTER. 

(155)  Geo.  Shaw,  Talmage,  Neb.,  has 
conceived  an  idea  for  the  improvement  of 
interrupters  for  small  wireless  sets  and 
other  outfits  requiring  the  use  of  a  small 
transformer  or  spark  coil.  The  idea  is  to 
use  a  certain  form  of  interrupter  in  an 
air-tight  chamber,  under  sufficient  air  pres- 
sure to  prevent  the  burning  of  the  con- 
tacts. He  thinks  that  a  small  hand  air 
pump  could  be  secured  to  the  chamber  to 
pump  up  sufficient  pressure.  Is  the  idea  a 
good  one  and  is  it  patentable,  and  would 
there  be  a  demand  for  it? 

Ans.  A  scheme  of  this  sort  is  decidedly 
not  satisfactory  because  it  has  been  shown 
that  comprest  air  will  retard  an  ordinary 
vibrator  spring  or,  for  that  matter,  any 
moving  part  which  is  supposed  to  operate 
under  high  speed.  If  instead  of  using 
comprest  air  you  use  a  vacuum,  enorm- 
ously better  results  are  obtained,  as,  for 
instance,  in  the  Moore  Vacuum  Interrupt- 
er. Personally,  we  have  no  faith  in  com- 
prest air  interrupters,  as  we  have  never 
seen  one  work  satisfactorily. 


ELECTRIC  CIGAR  MOISTENER. 

(156)  Charles  Bicker,  Salina,  Kans., 
says  that  he  has  an  idea  in  the  construc- 
tion of  a  device  to  moisten  cigars  and 
tobacco  in  show  cases.  The  idea  is  to 
make  steam  by  heat  developed  from  stor- 
age batteries,  and  to  evaporize  the  steam 
in  a  certain  manner. 

Ans.  While  a  patent  might  be  obtained 
on  a  scheme  of  this  kind,  we  do  not  know 
how  valuable  it  will  be  without  knowing 
full  details.  There  are  some  very  good 
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the  market  to-day  and  we  have  one  in 
mind  which  seems  to  have  the  greatest 
sale,  whereby  an  electric  incandescent 
lamp  is  plunged  in  a  basin  filled  with 
water,  which  owing  to  the  heat  of  the 
lamp,  is  made  to  evaporate. 


AMPLIFICATION  TRANSFORMER. 

(157;  A.  J.  Camile,  New  York,  N.Y., 
sends  in  a  sketch  and  description  of  a 
transformer  which  is  supposed  to  amplify 
alternating  current  ten  times  or  more 
without  any  other  means.  He  proposes  in 
a  sketch  and  description,  that  it  will  trans- 
form 110  volts  2  amperes  into  a  current 
of  110  volts  31  amperes! 

Ans.  No  matter  what  a  scheme  of  this 
kind  may  consist  of,  it  is  absolutely  im- 
possible. You  cannot  obtain  energy  for 
nothing  and  you  might  just  as  well  try  to 
lift  yourself  by  your  own  boot  straps.  It 
simply  cannot  be  done. 


PATENT  ATTORNEYS. 

(158)  Edmund  von  Szuppiny,  Pater- 
son,  N.J.,  writes  as  follows: 

"Wishing  to  find  out  thru  whose  services 
Edison,  Maxim,  or  Lewis  obtained  their 
patents,  I  sent  for  the  literature  of  a 
good  many  patent  attorneys. 

"Many  of  them  list  a  considerable  num- 
ber of  names  and  addresses  of  their  clients 
who,  however,  are  almost  all  unknown  to 
the  world  at  large,  and  no  matter  how  I 
tried,  I  failed  to  find  the  names  of  Tes- 
la,  Hammond,  etc.,  in  any  one  of  their 
lists. 

"This  makes  the  impression  upon  me  that 
inventors  of  this  magnitude  do  not  care 
to  intrust  their  inventions  to  the  adver- 
tising patent  attorneys. 

"Will  you  kindly  inform  me  what  means 
or  what  agencies  this — say  Edison  or  Tes- 
la — uses  when  wishing  to  patent  one  of 
their  inventions." 

Ans.  The  answer  is  a  simple  one  in- 
deed. We  have  good  reasons  to  believe 
that  several  of  the  greatest  inventors  of 
this  country  patronize  the  advertising  pat- 
ent attorneys,  but  they  usually  restrict  at- 
torneys from  using  their  name  for  obvi- 
ous reasons,  as  it  is  naturally  to  their  in- 
terest not  to  disclose  who  does  their  work 
for  them.  Personally,  we  think  you  will 
get  cheaper  and  better  service  from  ad- 
vertising patent  attorneys  than  from  those 
who  do  not  advertise,  for  the  simple  rea- 
son, that  the  former  do  a  larger  business 
and  consequently  can  work  cheaper.  The 
quality  of  a  patent  obtained  certainly  does 
not  make  a  lot  of  difference  whether  it  is 
turned  out  by  an  advertising  attorney  or 
by  one  that  does  not  advertise. 

The  editor,  who  is  the  owner  of  some 
eighteen  patents,  might  state  that  nearly 
all  of  these  were  obtained  from  advertis- 
ing patent  attorneys. 


TOY  ELECTRIC  HAMMER. 

(159)  R.  DeWitt  Duffield,  Van  Wert, 
Ohio,  has  submitted  to  us  a  simple  design 
of  a  toy  electric  hammer  and  wants  to 
know  if  such  an  article  is  on  the  market 
already  and  if  it  is  worth  while  patenting. 

Ans.  This  indeed  is  a  very  excellent 
idea  and  one  of  the  best  schemes  for  a" 
cheap  electric  toy  that  we  have  seen  late- 
ly. While  there  is  nothing  particularly  new 
in  the  principle,  we  are  certain  that  a 
patent  may  be  obtained  on  the  construc- 
tion of  same. 

Our  correspondent  also  submits  to  us  a 
sketch  of  an  electrolytic  interrupter  on 
which  he  desires  our  advice. 

Ans.  Nothing  new  is  shown  in  this  de- 
sign, and  similar  interrupters  are  in  use 
all  over  the  world  and  a  patent  can  cer- 
tainly not  be  obtained  on  this  device. 


JOE'S  EXPERIMENT. 

(Continued  from  page  101) 
forming  the  circle  which  surrounded  the 
erect  and  alert  chief,  his  pale  face  drawn 
and  anxious  as  he  eyed  the  watch  he  held 
in  one  hand. 

"Do  you  think  they'll  stand  it?"  he 
asked  in  husky,  worried  tones. 

"Sure,  there  isn't  much  load  on,"  Pete 
Foley  assured  him. 

It  was  just  a  minute  before  twelve.  The 
generators  below  were  purring  smoothly, 
filling  the  whole  building  with  a  vibrant, 
steady  hum. 

Five  seconds  past  —  ten  —  twenty  —  the 
group  grew  silent,  watching  the  chief,  Mr. 
Robertson,  as  he  squared  himself  in  front 
of  the  main  control  panel.  Twenty-five 
seconds  past — thirty — forty. 

At  ten  seconds  before  twelve  Mr.  Rob- 
ertson reached  for  the  push-button  in  the 
center  of  the  panel  marked,  "Main  Switch." 

His  hand  rested  on  the  metal  disc  for  a 
moment  and  then  as  the  watch  held  in  his 
left  hand  marked  five  seconds  before 
twelve,  he  prest  the  button. 

There  was  a  purr  of  mechanism  behind  the 
marble  panel  as  the  big  main  switch  fell  into 
place.  The  generators  dipt  a  note  or  two  in 
their  hum,  and  then  rallied  as  more  water 
came  thru  on  their  turbines.  The  group 
watched  the  voltmeter  on  the  panel 
anxiously,  and  as  the  seconds  past  and 
it  did  not  waver,  Mr.  Robertson  heaved  a 
great  sigh  of  relief  and  satisfaction. 

"It  works !  It  works !"  he  shouted,  in 
sudden  released  exuberance.  "They've  got 
their  power  and  we've  got  our  franchise." 

A  white-linened,  diamond-pinned  director 
reached  for  the  chief's  hand. 

"Don't  congratulate  me,"  Mr.  Robertson 
hastened  to  forestall  him.  "We're  saved 
because  some  one  thought  of  a  very  simple 
expedient.    Here,  I'll  show  you." 

He  stept  to  a  panel  at  his  right,  followed 
by  the  interested  group.  He  paused  before 
a  rheostat,  glittering  in  bright  metal.  From 
its  connections  two  wires  led  down  to  a 
coil  of  wire  on  the  floor. 

"This  coil,"  he  said,  indicating  it,'  "is  a 
resistance  coil.  It  is  connected  in  series 
with  the  field  windings  of  the  exciter.  In 
this  way  the  voltage  of  the  exciter  has  been 
lowered,  thereby  reducing  the  strength  of 
the  alternator's  field,  which  in  turn  lowers 
the  voltage  of  the  machine  itself.  As  a 
result  we  have  the  voltage  of  the  high 
tension  line  lowered  to  such  a  point  that 
we  are  sending  current  directly  into  the 
Merwin  service  lines  without  any  inter- 
vening step-down  transformer.  A  very 
clever  and  simple  expedient,  which  will 
work  until  the  transformers  arrive.  And 
so  I  congratulate  the  man  who  suggested 
it  to  me,  Mr.  Peter  Fo  " 

"No,  you  don't.  Not  me,"  Pete  inter- 
rupted, as  Mr.  Robertson  turned  to  him. 
"Here's  the  boy  you  want  to  thank.  He 
saved  your  plant  and  not  me,"  and  he 
pushed  forward  Joe  Benson  from  the  shel- 
ter of  the  post  where  he  had  been  standing. 

"He  told  me  about  this  trick  and  asked 
me  to  tell  you.  So  just  give  him  the  thanks 
and  the  reward,"  Pete  went  on,  eyeing  in 
triumph  the  astonished  faces  of  the  group 
about  him. 

"It  wasn't  much.  Any  electrical  man 
could  have  thought  of  it,"  Joe  said  mod- 
estly, blushing  happily  in  sudden  confusion. 
"And  anyhow  I  couldn't  have  done  it,  if 
Pete  hadn't  showed  me  things  so  well  the 
day  I  was  here  looking  around." 

"Yes,  that  was  the  day  he  was  in  the 
way,"  Pete  said,  with  a  significant  glance 
toward  Mr.  Robertson. 

But  the  chief  had  recovered  from  his 
surprise  and  had  stept  forward  to  the  blind 
(Continued  on  page  152) 


Yon  benefit  by  mentioning  "The  Electrical  Experimenter"  when  writing  to  advertisers. 


June,  1917 


THE   ELECTRICAL  EXPERIMENTER 


151 


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YOU  NEED  AN  0MNIGRAPH— NOW 

We  have  been  telling  you  for  years  of  the  merits  of  THE  OMNIGRAPH 
AUTOMATIC  TRANSMITTER.     We  have  been  telling  you  that  the  Omni-  . 
graph,  connected  with  a  wireless  Buzzer,  will  send  you  unlimited  Continental 
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from  your  favorite  Electrical  House.  THE  OMNIGRAPH  is  sold  under  the 
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THE  OMNIGRAPH  MFG.  CO. 


41  Cortland  St.,  N.  Y. 


This  cut  shows  an  Omnigraph  aluminum  disc 
with  message  milled  around  the  edge.  It  is 
only  one  of  hundreds  of  different  styles  of 
discs  we  make. 


You.  benefit  by  mentioning  "The  Electrical  Experimenter"  when  tvriting  to  advertisers. 


152 


THE  ELECTRICAL  EXPERIMENTER 


June,  1917 


BEFORE   they   started   to  coast 
this  hill  they  knew  from  past 
experience  that  they  were  taking 
no    chances — they    knew    that  they 
could  rely  absolutely  upon  the  pow- 
erful grip  of  the  famous 


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JOE'S  EXPERIMENT. 

(Continued  from  page  150) 
boy,  before  the  circle  of  directors  could 
close  in  on  him. 

"Shake,"  he  cried,  gripping  his  hand. 
"Any  boy  who  can  think  of  a  thing  like 
that  deserves  a  chance  to  learn  more, 
whether  he  can  see  or  not.  So  if  the  com- 
pany doesn't  out  of  gratitude,  I'll  see  to 
it  myself  that  you  go  to  the  best  technical 
school  in  the  country." 


ELECTRICITY  AND  LIFE. 

(Continued  from  page  105) 
culosis  and  other  pulmonary  troubles  often 
yield  to  the  "effleuve"  treatment. 

3.  Perhaps  the  most  remarkable  therau- 
peutic  effect  of  heavy  high-frequency  cur- 
rents is  their  power  to  liberate  heat  in  the 
tissues  of  the  body.  For  this  purpose  the 
so-called  "D'Arsonval  current"  is  used. 
This  is  a  secondary  current  of  high 
amperage  derived  from  the  heavy  coil  of 
copper  strip  shown  in  Fig.  6.  The  lower 
terminal  of  this  coil  is  connected  with  the 
condenser  pad  on  which  the  patient  is 
seated ;  the  tubular  metal  electrode  is  held 
in  both  hands  and  connected  thru  a  Milli- 
amperemeter  with  the  upper  turns  of  the 
coil.  The  clip  is  moved  to  different  turns 
as  in  wireless  tuning,  until  the  meter  shows 
the  highest  reading  for  a  given  amount  of 
exciting  current.  The  patient's  circuit  is 
in  this  way  tuned  in  perfect  resonance 
with  the  primary  oscillations.  After  a  few 
moments  the  patient's  wrists  become  hot, 
the  heat  rapidly  extending  up  the  arms  and 
into  the  body  until  profuse  perspiration 
is  produced.  Ordinarily  we  do  not  carry 
the  treatment  as  far  as  this :  the  safe 
dose  for  an  average  patient  being  not 
over  700  milliamperes  for  twenty  minutes. 
This  is  "D'Arsonval  Autocondensation", 
and  is  applied  with  great  benefit  to  patients 
suffering  with  Arteriosclerosis  ("harden- 
ing of  the  arteries"),  and  in  a  variety  of 
other  diseased  conditions  involving  mal- 
nutrition. 

4.  In  diseases  in  which  we  wish  to  in- 
duce a  regenerative  inflammation,  promote 
circulation  and  absorption,  and  increase  cell 
activity,  the  method  known  as  "Diathermie" 
is  employed.  Instead  of  the  hand  electrode 
and  condenser-pad  the  D'Arsonval  current 
is  applied  thru  two  small  sheets  of  block- 
tin  about  2x4  inches.  These  are  applied 
to  the  skin  on  either  side  of  the  affected 
part  and  a  current  employed  which  gives 
the  patient  a  decided  sensation  of  penetrat- 
ing heat.  Average  treatments  use  from 
1000  to  1600  milliamperes.  In  treating  con- 
sumption (pulmonary  tuberculosis)  one 
electrode  is  placed  on  the  back  and  the 
other  on  the  chest  over  the  affected  lung. 
One  Tuberculosis  Hospital  in  which  this 
treatment  was  given  daily  to  a  number 
of  patients  reported  85  per  cent  of  cures! 
The  author  is  working  on  an  apparatus 
which  will  make  possible  the  use  of  Dia- 
thermic treatment  in  the  homes  of  patients 
suffering  from  this  disease. 

For  office  use  and  for  the  Electro-medi- 
cal specialist  ("Electrotherapeutist")  the 
writer  has  recently  designed  an  apparatus 
from  which  remarkable  results  are  being 
obtained  (see  Fig.  6).  The  Tesla  and 
D'Arsonval  coils  are  excited  by  a  wireless 
transmitting  set  of  the  well-known  "Hy- 
tone"  type.  The  rotary  quenched  gap  with 
its  exceedingly  high-spark  frequency  pro- 
duces an  almost  sustained  wave  in  the 
High-frequency  coils.  Both  for  the  Tesla 
and  D'Arsonval  treatment  the  writer  be- 
lieves this  apparatus  superior  to  any  that 
he  has  used  up  to  the  present  time.  The 
vitalizing-  and  exhilarating  effects  are  ex- 


tremely pronounced.  The  machine  has  the 
added  advantage  that  there  is  no  trouble- 
some spark  gap  to  adjust,  the  strength  of 
the  current  being  regulated  by  a  many- 
stept  rheostat  in  the  primary  transformer 
circuit. 

Much  has  been  done  in  adapting  high- 
frequency  currents  to  the  treatment  of 
disease,  but  much  remains  yet  to  be  done 
before  we  shall  be  able  to  avail  ourselves 
of  the  wonderful  healing  and  vitalizing 
powers  which  these  currents  undoubtedly 
possess.  The  writer  hopes  to  be  able  to 
continue  his  studies  along  this  line,  be- 
lieving that  when  we  can  scientifically  apply 
to  our  patients  pure  undamped  waves  of 
definite  form,  frequency,  amperage  and 
voltage,  we  will  obtain  results  far  surpassing 
anything  that  we  have  dreamed  of  up  to 
the  present  time,  and  that  in  the  future 
the  scientific  use  of  high-frequency  cur- 
rents will  become  the  greatest  method  ever 
discovered  for  the  healing  of  disease,  the 
promotion  of  health  and  the  maintenance 
of  a  "More  Abundant  Life!" 


EXPERIMENTAL  PHYSICS. 

(Continued  from  page  106) 

goes  out  solidly,  so  that  now  our  siphon 
has  its  "arms"  filled  and  acts  the  same  as 
the  ordinary  siphon. 

EXPERIMENT  28— The  following  is  an 
interesting  and  amusing  experiment.  It  can 
be  made  to  appear  mysterious,  and  is  im- 
portant because  in  it  lies  the  principle  of 
the  submarine.  In  Fig.  24-A,  3  is  a  jar  or 
other  cylindrical  glass  vessel  about  two- 
thirds  full  of  water.  2,  is  a  small,  light 
glass  bottle,  or  better,  a  small  glass  vial. 
1,  is  a  piece  of  sheet  rubber  stretched  over 
the  top  of  the  jar.  Before  placing  1  in 
position,  vial  2  is  partly  filled  with  water 
and  inverted  so  that  it  just  floats  upright. 
On  pushing  down  on  the  sheet  rubber  the 
vial  (Cartesian  diver)  sinks  and  on  releas- 
ing it  rises  again.  When  we  push  down 
on  the  sheet  rubber,  we  compress  the  air 
in  the  jar  and  hence  it  forces  more  water 
into  the  vial.  Since  it  was  originally  ad- 
justed so  that  it  just  floated,  the  addition  of 
more  water  into  the  vial  makes  it  heavier 
and  hence  it  sinks.  On  releasing  the  sheet 
rubber  the  pressure  in  the  jar  becomes  nor- 
mal again,  and  hence  the  pressure  in  the 
vial  causes  the  excess  water  to  come  out 
and  the  vial  returns  to  its  original  position. 
Fig.  24-B,  shows  a  more  mystifying  form 
of  the  same  experiment.  3,  is  a  Florence 
flask,  while  2,  is  the  same  vial  adjusted 
exactly  as  in  Fig.  24-A.  1,  is  an  ordinary 
cork  stopper.  After  the  vial  is  adjusted, 
the  stopper  is  put  in  carefully.  (It  may  be 
necessary  to  adjust  the  vial  so  that  it  floats 
almost  upright  so  that  on  pushing  in  the 
stopper,  a  little  more  water  enters  the  vial 
and  it  just  floats  upright.)  On  holding  the 
flask  in  the  hand  it  is  found  that  one  can, 
by  squeezing  it,  compress  the  air  and  make 
the  diver  perform.  Thus  one  can  make  the 
diver  obey  one's  command  to  rise  or  sink, 
without  the  audience  perceiving  the  cause. 
Obviously  a  thin  flask  which  will  yield  to 
squeezing  is  necessary  for  this  experiment 
and  the  ordinary  Florence  flask  answers 
the  purpose  very  well.  The  real  submarine 
boat  is  so  constructed  that  no  water  can 
enter  it,  even  if  it  is  wholly  submerged,  ex- 
cept at  the  will  of  the  occupants.  It  is 
able  to  float  like  any  other  ship  just  as  our 
vial  can  float.  If  the  occupants  wish  the 
boat  to  submerge,  water  is  allowed  to  enter 
into  special  compartments  until  the  weight 
of  the  boat  slightly  exceeds  the  weight  of 


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June,  1917 


THE   ELECTRICAL  EXPERIMENTER 


153 


the  water  it  displaces.  When  they  wish 
to  rise  again,  some  of  this  water  is  forced 
out. 

EXPERIMENT  29— We  are  all  familiar 
wiih  the  fact  that  objects  weigh  less  in 
water  than  in  air  and  that  some  things 
float  in  water.  No  one  who  has  ever  taken 
a  hath  has  failed  to  notice  this,  and  as  a 
matter  of  fact  the  great  Archimedes,  who 
first  formulated  the  law  of  buoyancy,  first 
noticed  the  buoyant  effect  of  water  while 
taking  his  daily  or  yearly  bath  (I  do  not 
know  which).  If  a  block  of  wood,  a  piece 
of  stone  or  marble,  or  a  brick  and  a  piece 
of  cork  of  the  same  size  and  shape  are 
weighed  in  air,  they  are  found  to  have 
different  weights.  If  then  each  is  weighed 
in  water  (see  Fig.  2S-A)  they  are  again 
found  to  weigh  differently  but  they  all 
weigh  less,  and  as  a  matter  of  fact  it  is 
noticed  that  the  LOSS  IN  WEIGHT  is  in 
each  case  the  same,  except  in  the  case  of 
the  cork  which  floats  and  does  not  weigh 
anything.  If  next  we  fill  a  can  until  it 
nearly  overflows  and  immerse  one  of  our 
objects  (except  the  cork)  in  it,  and  catch 
the  overflow  water  in  another  can  and 
weigh  it  (subtracting  the  weight  of  the 
can),  we  find  that  the  weight  of  the  water 
displaced  is  equal  to  the  weight  lost  ivhen 
the  bodies  were  immersed  in  the  first  part 
of  the  experiment.  In  Fig.  25-B,  abed, 
represents  the  cross-section  of  the  body 
used.  The  pressure  at  ad,  is  equal  to  the 
weight  of  the  column,  eoad.  The  pressure 
at  cb,  is  equal  to  the  weight  of  the  column, 
ceob.  The  difference  between  the  two  is 
the  resulting  buoyant  force  at  cb,  and  is 
equal  to  the  weight  of  a  column  of  water 
adeb,  which  of  course  is  the  amount  of 
water  displaced.  The  cork  being  lighter 
than  water,  if  it  were  immersed  the  buoy- 
ant force  would  be  greater  than  its  weight 
and  therefore  it  is  forced  to  the  surface. 
Hence  the  cork  will  sink  only  until  enough 
water  is  displaced  so  that  the  buoyant  force 
equals  its  weight,  i.e.,  only  part  of  it  will 
sink.  The  ordinary  ship  floats  because  it  is 
constructed  so  that  if  it  were  immersed, 
the  buoyant  force  would  be  greater  than  its 
weight. 

(To  be  continued) 

THE  NAVAL  RADIO  OPERATOR. 

(Continued  from  page  109) 
Members  of  the  Electrical  Class  are 
quartered  on  the  receiving  ship  at  either 
Mare  Island  or  New  York.  The  school 
buildings  are  situated  in  the  Navy  Yard. 
Outside  of  the  regular  school  hours  a 
course  of  instruction  is  contemplated 
whereby  they  will  be  instructed  in  the  regu- 
lar duties  of  a  man-o'-war's-man ;  this  is 
necessary,  as  every  man  aboard  ship,  irre- 
spective of  rating,  is  a  member  of  a  mili- 
tary organization.  Shore  leave  is  granted 
in  accordance  with  the  regular  Navy  cus- 
tom, usually  from  4:30  p.  m.  to  7:30  a.  m. 
every  other  day.  Leave  of  absence  is 
granted  after  completion  of  course. 

The  course  at  the  Electrical  School  com- 
prises twenty-two  weeks  of  advance  work 
and  three  weeks  of  examination.  The 
schedule  of  marking  is  based  on  4  as  per- 
fect and  a  final  average  of  2.8  is  neces- 
sary in  order  to  obtain  the  rating  of  elec- 
trician upon  graduation.  Each  man  is 
assigned  a  mark  upon  daily  oral  recitations 
and  weekly  written  examinations.  The 
final  examination  is  in  writing.  In  the 
radio  course  the  greatest  emphasis  is  placed 
upon  the  ability  to  send  and  receive  the 
Morse  and  Continental  codes,  also  radio 
regulations. 

OUTLINE  OF  THE  RADIO  COURSE. 

The  outline  of  the  radio  course  is  as 
follows : 


Machine  Shop  (bench  work). 

Magnetism  and  Electricity. 

Alternating  Currents. 

A.  C.  and  D.  C.  Instruments. 

Batteries. 

Motors  and  Motor  Control. 

Radio  Power  Circuits. 

P'rimary  Circuits. 

Secondary  Circuits. 

Condensers  and  Oscillating  Currents. 

Radiating  Currents. 

Transmitting  Sets. 

Receiving  Circuits. 

Receiving  Sets. 

Service  Radio  Sets  and  Routine. 

Wave  Meters  and  Measurements. 

Radio  Regulations  and  Fleet  Work. 

Radio  License  Booth. 

Review  and  Examination. 
To  the  above  course  is  added  several 
weeks  of  practical  work  and  special  details. 
Students  enter  the  Electrical  School  at  any 
time  and  commence  the  course  on  the 
Monday  following  their  date  of  entrance. 
Each  week  corresponds  to  a  class  or  grade 
and  shows  the  subject  which  the  student 
is  studying,  and  the  lapse  of  time  since 
entrance  to  the  school. 

The  first  eight  weeks  of  the  radio  course 
are  devoted  to  subjects  pertaining  chiefly 
to  general  electricity  and  serve  as  the 
ground  work  for  the  study  of  radio.  Text 
books  used  in  the  first  eight  weeks  are 
"Swoope's  Lessons  in  Practical  Electricity" 
and  "Bullard's  Naval  Electricians'  Text 
Book." 

Both  the  Continental  and  Morse  codes 
arc  taught.  Two  operating  tables,  each 
with  a  capacity  of  twenty  men,  are  fitted 
with  head  'phones,  sounders,  and  trans- 
mitting keys.  The  instructors  are  Chief 
Radio  Electricians.  Each  instructor  is  as- 
signed an  operating  desk  having  control 
over  a  certain  number  of  tables.  The  stu- 
dents are  assigned  to  tables  according  to 
skill  in  receiving  and  are  advanced  to 
faster  tables  whenever  necessary.  Final 
examinations  are  held  after  the  comple- 
tion of  the  twenty-second  week.  The  av- 
erage operating  ability  of  the  students 
completing  the  course  is  25  words  per 
minute.  A  great  many  of  the  students, 
however,  approach  a  speed  of  30  words 
per  minute. 

It  is  believed  that  men  completing  the 
radio  course  at  the  Electrical  Class  suc- 
cessfully have  obtained  an  excellent  gen- 
eral knowledge  of  radio  and  have  fitted 
themselves  for  rapid  and  sure  promotion 
in  this  branch  of  the  Naval  service. 


THE  HOW  AND  WHY  OF  RADIO 
APPARATUS. 

(Continued  from  page  113) 
chanical  pressure  can  be  exerted  axially 
upon  them,  in  order  to  make  the  gaps  thoro- 
ly  air  tight.  For  outputs  above  one-half 
K.W.,  the  gap  often  becomes  unduly  heated, 
and  it  is  common  practise  to  place  a  small 
motor-driven  blower  or  fan  beside  the  gap, 
in  order  to  cool  it  by  carrying  off  heat  from 
the  cooling  flanges. 

At  Fig.  4,  we  have  what  is  known  as  a 
rotary-quenched  spark  gap.  This  particular 
design  of  gap  has  met  with  considerable 
favor,  especially  for  small  radio  transmit- 
ters, of  from  one-quarter  to  several  kilo- 
watts output.  This  gap  possesses  the  dis- 
tinct and  remarkable  quality  of  producing 
a  high-tone  in  the  telephones  at  the  receiv- 
ing station,  even  tho  it  is  used  on  a  low 
frequency  or  60  cycle  transformer  at  the 
transmitting  station. 

In  the  first  place,  this  gap  operates  with 
a  remarkably  small  clearance  between  its 
two  semi-circular  fixt  spark  electrodes  and 
its  rotary  electrode,  or  having  a  gap  about 


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154 


THE  ELECTRICAL  EXPERIMENTER 


June,  1917 


PORCELAIN 

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three-thousandths  of  an  inch  in  length. 
The  gap  operates  in  an  air-tight  chamber 
formed  by  a  heavy  metallic  casting,  which 
carries  suitable  cooling  vanes,  and  besides 
which  there  are  provided  a  number  of  aux- 
iliary cooling  vanes  as  shown  in  Fig.  4,  at 
the  rear  of  the  gap.  Being  air-tight  at  the 
start,  this  gap  operates  in  the  same  manner 
as  the  design  shown  in  Fig.  3,  known  as 
the  Telefunken  gap.  To  obtain  a  high 
spark  note  with  the  rotary  quenched  gap  of 
Fig.  4,  the  two  fixt  and  also  the  rotary  elec- 
trodes have  their  faces  accurately  machined 
or  milled-out  at  equal  distances,  resulting 
in  a  number  of  teeth,  .between  which  the 
spark  occurs.  These  gaps  have  to  be  built 
very  accurately  of  course,  as  the  gap  itself 
measures  about  .003  inch,  and  it  is  desirable 


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to  have  the  sparking  distances  constant  and 
similar.  A  typical  gap  of  this  class  has  the 
sparking  surfaces  and  the  copper  on  both 
stationary  and  rotary  elements  milled  with 
th*irty-six  radial  slots,  so  that  when  rotated 
by  a  small  motor  at  1,800  R.P.M.,  the  re- 
sultant tone  corresponds  to  that  of  a  540- 
cycle  alternator.  It  is  necessary  that  the 
width  of  the  spark  segments  are  so  propor- 
tioned that  sparks  will  occur  during  not 
more  than  one-half  of  the  total  time,  as 
otherwise  the  telephone  diafram  at  the  re- 
ceiving station  is  retarded  in  its  excursion, 
away  from  the  magnet,  thereby  resulting 
in  a  decrease  in  the  sound  intensity. 

[Those  interested  in  this  spark  gap  will 
do  well  to  look  up  the  matter  in  the  excel- 
lent paper  by  Mr.  Melville  Eastham,  entitled 
"The  High  Tone  Radio  Telegraph  Trans- 
mitter" in  the  December,  1914,  issue  of  the 
proceedings  of  the  Institute  of  Radio  En- 
gineers.— Editorial  Note.] 

HIGH-FREQUENCY  APPARATUS 
AND  EXPERIMENTS. 

{Continued  from  page  117) 
so  rapid  that  it  will  not  produce  an  audible 
sound  in  the  receivers,  so  that  the  discharge 
of  an  Oudin  coil  cannot  be  used  for  the 
transmission  of  wireless  messages,  altho 
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the  aerial,  that  it  does  not  travel  as  far  or 
farther,  than  an  undamped  wave. 

It  is  very  probable  that  high  frequency 
current  of  a  periodicity  which  is  not  de- 
tected by  the  senses,  will  play  an  important 
part  in  radio  thought  transmission. 

If  experimenters  will  build  apparatus, 
similar  to  that  described,  they  will  never  re- 
gret the  little  amount  of  time  required  for 
its  construction. 


EXPERIMENTAL  CHEMISTRY. 

{Continued  from  page  127) 

be  left  in  a  closet,  or  some  place  else  for 
a  week,  or  until  the  water  has  disappeared. 
The  reaction  for  this  experiment  is : 

3Cu   +  8HN03  =  3Cu[N03]2  +  4H20  4-  2NO 
Copper        Nitric  Copper        Water  Nitrogen 

Nitrat 


Acid 


Monoxid 


MADE  FROM  ACIDS  AND  SALTS. 
EXPERIMENT  NO.  61— 

Put  5  or  10  grams  of  marble  chips  into 
a  wide  test  tube  and  add  about  10  cc.  of 
dilute  Nitric  acid,  [HNOs]  [half  acid  and 
half  water].  Apply  the  splint  test  by  ap- 
plying a  lighted  splint  to  the  mouth  of  the 
test  tube,  after  the  action  has  progrest  for 
a  short  time.  After  the  action  has  stopt, 
and  if  not  clear,  filter,  and  evaporate  most 
of  it. 


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THE   ELECTRICAL  EXPERIMENTER 


155 


EXPERIMENT  NO.  62— 

Put  2  or  3  grams  of  Ferrous  sulfid 
[FeS]  in  a  test  tube  and  cover  it  with 
water.  Place  this  near  an  open  window, 
or  in  a  place  where  a  draft  of  air  can  be 
created  to  carry  away  the  escaping  fumes. 
Add  5  cc.  of  Hydrochloric  acid  |HC1] 
[keeping  in  a  draft  of  air].  When  the 
action  stops,  filter  and  evaporate.  Equa- 
tion : — 

FeS      +        2HC1        =    FeCIo     +  H«S 
Ferrous        Hydrochloric        Ferrous  Hydrogen 
Sulfid  Acid  Chlorid  Sulfid 

EXPERIMENT  NO.  63— 

Put  10  grams  of  fine  salt  [Sodium 
Chlorid]  [NaCl]  in  a  large  test  tube,  and 
add  10  cc.  of  concentrated  Sulfuric  acid 
[H2S04].  Carry  on  this  experiment  near 
a  window  or  where  a  draft  of  air  can 
be  created.  Heat  the  solution  over  a  Bun- 
sen  burner  very  cautiously,  and  moderately. 
After  the  action  has  progrest  for  5  or  10 
minutes  let  the  tube  cool,  then  pour  in  15 
or  20  cc.  of  water,  to  dilute  or  dissolve  the 
solution.  If  the  liquid  is  not  clear,  filter 
it,  and  evaporate  the  filtrat  [the  liquid 
which  passes  thru  the  filter  paper].  If 
concentrated  sulfuric  acid  is  present,  it  will 
destroy  the  filter  paper. 

Equation : — 

2NaCl    +     H,,S04    =  Na^SC^   +  2HCI 
Sodium         Sulfuric         Sodium  Hydrochloric 
Chlorid  Acid  Sulfate  Acid 

Soluble  and  Insoluble  Substances. 

All  the  common  acids  are  soluble.  Some 
of  the  bases  are  soluble,  some  insoluble. 
An  insoluble  substance  is  one  which  does 
not  dissolve,  or  which  dissolves  very  slightly 
in  water.  Besides  water  there  are  many 
other  solvents,  as,  alcohol,  chloroform, 
ether,  carbon  disulfid,  and  the  various 
alkalis,  and  acids,  and  unless  a  certain  sol- 
vent is  mentioned,  water  is  the  one  re- 
ferred to.  To  be  able  to  distinguish  clearly 
between  soluble  and  insoluble  substances, 
is  the  basis  of  chemical  analysis. 

Soluble  salts,  are  usually  prepared  by 
[1]  neutralization,  as  in  experiments  54,  55 
and  56;  [2]  by  the  action  of  an  acid  on 
a  metal,  as  in  experiments  58,  59  and 
60;  [3]  by  the  action  of  an  acid  on  a  salt, 
as  in  experiments  61,  62,  63. 

In  experiments  54,  55  and  56,  we  pre- 
pared a  soluble  salt  by  Neutralization. 
Upon  making  a  mixture  of  the  acid  and 
base  [in  solution]  a  reaction  took  place 
and  a  salt  was  formed.  As  a  salt  usually 
gives  a  neutral  reaction,  a  point  is  reached, 
in  the  mixing,  if  it  is  done  very  care- 
fully, at  which  the  whole  mixture  was 
neutral  to  litmus.  If  the  solvent  water 
was  evaporated  at  this  point,  the  salt 
should  be  obtained  as  a  solid,  which  in 
some  cases  may  break  up  owing  to  ex- 
cessive heat. 

In  experiments  58,  59  and  60,  we  pre- 
pared a  soluble  salt  by  dissolving  a  metal 
by  an  acid.  The  result  which  we  obtained 
is  called  a  chemical  solution  and  consists 
of  two  stages;  [1]  the  metal  combined 
with  the  negative  part  of  the  acid,  and 
formed  a  salt;  [2]  the  salt  dissolved  in 
the  liquid,  the  larger  part  of  which  is 
water.  Thus  it  is  clear  why  a  salt  which 
is  insoluble  in  water  is  not  usually  made 
in  this  manner. 

In  experiments  61,  62  and  63,  we  made 
a  soluble  salt  by  the  action  of  an  acid 
on  other  salts  or  compounds.  Metallic 
oxids,  carbonats,  and  sulfids  are  the  most 
common  of  these.  Suppose  we  wish  to 
make  some  calcium  chlorid  [CaCU].  We 
know  that  it  is  soluble,  and  suppose  that 
Hydrochloric  acid  [HC1]  will  probably  dis- 
solve the  calcium.  But  we  also  learn  that 
calcium  is  not  a  common  metal  in  the 
laboratory,  so  we  look  for  an  inexpen- 
sive  compound   upon   which    the  Hydro- 


chloric   acid    will    act.      The  carbonat 
[CaCOa,  limestone,  or  marble],  is  plenti- 
ful, and  hydrochloric  acid  attacks  it  with 
great  vigor.    The  reaction  would  be : 
CaCO.,    +      2HC1      =  CaCl2  +  H2(J  +  COa 
Calcium       Hydrochloric   Calcium  Water  Carbon 
Carbonat  Acid  Chlorid  Dioxid 

[Limestone, 
or  Marble] 

Insoluble  substances,  salts  and  bases,  are 
prepared  in  the  laboratory  almost  wholly 
by  one  process,  Precipitation.  An  insoluble 
salt  or  base  may  be  made  by  mixing  two 
solutions,  one  of  which  contains  a  com- 
pound of  the  metal,  the  other  a  compound 
of  the  non-metallic  part  of  the  insoluble 
salt,  which  will  appear  in  the  mixture  as 
a  precipitat.  Lead  sulfat  [PbSOi]  is  made 
by  pouring  a  solution  of  lead  nitrat 
]Pb[NO.i]-.j  upon  a  solution  of  Sodium 
sulfat   [Na,SO,|  . 

PbtNOaL,  +     Na2SO,     =     PbSO.,    +  2NaNOa 
Lead  Nitrat  Sodium  Sulfate  Lead  Sulfate  Sodium 
iprecipitatsj  Nitrat 

Acids  are  usually  made  by  acting  with 
a  less  volatile  acid,  as  Sulfuric  acid 
[HaSOt],  on  a  salt  of  the  acid  required. 
We  have  seen  that  salts  can  be  made  by 
the  union  of  an  acid  and  a  base,  and  we 
now  learn  that  an  acid  can  be  obtained 
from  its  representative  salt.  Sulfuric  acid 
is  generally  used,  for  making  acid,  be- 
cause it  is  one  of  the  less  volatile  acids, 
and  thus  it  readily  parts  with  its  hydro- 
gen and  takes  a  metal  in  its  place.  A 
salt  of  the  acid  desired  must  be  put  with 
the  sulfuric  acid ;  for  example,  if  Hydro- 
chloric acid  [HC1]  is  wanted,  Sodium 
chlorid  [NaCl]  or  some  chlorid  is  used. 
If  Nitric  acid  [HNO.i]  some  nitrat,  as  Po- 
tassium Nitrat  [KNOs],  should  be  used. 

Soluble  bases,  especially  the  alkalis,  may 
be  made  by  acting  with  calcium  hydroxid 
on  certain  salts  of  the  base  required. 
Other  bases,  for  example  Sodium  or  Potas- 
sium Hydroxid,  may  be  used  in  place  of 
Calcium  hydroxid.  Ammonium  hydroxid 
[NH4OH]  is  prepared  from  a  salt  of 
Ammonium,  as,  Ammonium  Chlorid 
[NH.Cl],  Ammonium  Nitrat  [NH.NO>], 
Ammonium  Sulfat  [NHuhSOi,  etc.,  by 
heating  it  with  a  mixture  of  calcium  hy- 
droxid [Ca[OH]2]   [slaked  lime]. 

2NH4C1    +    Ca[OH]2    =  CaCl2  +  2NH4OH 
Ammonium         Calcium         Calcium  Ammonium 
Chlorid  Hydroxid        Chlorid  Hydroxid 

[Slaked  lime] 

Sodium  hydroxid  is  made  from  Sodium 
Carbonat  [Na-COs]  and  Calcium  Hydroxid. 

Insoluble  bases  are  made  by  mixing  two 
solutions,  one  of  which  contains  a  base 
and  the  other  a  compound  of  the  metal 
of  the  base  required.  Ferric  Hydroxid 
[Fe[OH]2]  can  be  prepared  by  adding  So- 
dium hydroxid  solution  to  a  solution  of 
Ferric  chlorid  [FeCl3].  Any  other  soluble 
ferric  [but  not  ferrous]  salt  would  do  as 
well,  and  any  other  soluble  hydroxid. 
Ferrous  hydroxid  [Fe[OH]2]  requires  a 
soluble  ferrous  [not  ferric]  salt. 

SOLUTION  :— 

In  Experiment  5  [August,  1916,  issue  of 
The  Electrical  Experimenter]  we  illus- 
trated Solution  by  experiment.  We  found 
that  by  dissolving  the  sugar  in  water,  we 
formed  a  Solution.  Sugar  is  said  to  be 
Soluble  in  water,  and  the  water  is  termed 
the  Solvent.  The  sugar  is  the  Solute.  A 
substance  is  said  to  be  in  solution  in  a 
given  liquid,  when  it  is  evenly  distributed 
thruout  the  liquid  in  such  line  division 
that  its  particles  cannot  be  seen,  and  which 
do  not  settle  or  precipitate  upon  stand- 
ing. 

The  most  important  property  of  water 
is  its  ability  to  dissolve  a  large  number 
of  substances.    Liquids  which  do  not  sepa- 
rate but   form  a  uniform  mixture  when 
(Continued  on  page  156) 


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THE  ELECTRICAL  EXPERIMENTER 


June,  1917 


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How  About  You  Young  Man? 
Tou  who  have  wrecked  your  future  by  de 
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LIONEL  STRONGFORT 

.  „  Physical  Culture  Expert 
130  Park  Building  NEWARK.  N.  J 


brought  together,  such  as  alcohol  and  water, 
or  glycerine  and  water,  are  said  to  be 
Miscible. 

An  insoluble  solid,  like  starch-powder 
or  clay,  can  be  dispersed  thru  water  by 
shaking,  but  the  mixture  will  be  Turbid 
like  muddy  water.  A  turbid  mixture  of 
a  solid  and  liquid  is  called  a  Suspension. 
In  time  the  suspended  matter  will  settle, 
leaving  the  liquid  clear.  Dissolved  matter 
will  never  settle. 

SOLUBILITY  FACTORS:— 

The  solubility  of  most  substances  is  de- 
cidedly affected  by  the  temperature.  Solids 
are  usually,  but  not  always  more  soluble 
in  liquids  at  high  than  at  low  temperature. 
In  Experiment  5,  -we  found  that  sugar 
was  more  soluble  in  hot  water  than  in  cold. 
Calcium  Hydroxid,  vised  in  the  preparation 
of  limewater,  is  more  soluble  in  cold  water 
than  in  warm  water. 

The  solubility  of  gases  decreases  as  the 
temperature  rises.  Ammonia  and  Carbon 
dioxid  are  less  soluble  in  hot  water  than 
they  are  in  cold  water.  Different  sub- 
stances vary  very  much  in  their  solubility 
in  a  given  solvent,  and  different  solvents 
differ  in  their  power  to  dissolve  the  same 
substances. 

SATURATION:— 

If  a  small  portion  of  salt  is  dissolved 
in  a  large  quantity  of  water,  such  a  solu- 
tion is  then  said  to  be  Dilute.  The  sub- 
stance is  uniformly  distributed  in  all  parts 
of  the  liquid  in  a  dilute  solution,  as  it  is 
in  one  containing  a  much  larger  propor- 
tion of  the  dissolved  substance. 

By  slowly  adding'  salt  to  a  measured 
volume  of  water,  it  can  be  shown  that  there 
is  a  limit  to  the  quantity  which  the  water 
will  dissolve.  One  liter  of  water  at  20°  C. 
will'  take  up  any  quantity  of  salt  up  to  360 
grams,  and  no  more. 

At  this  point  the  solution  is  said  to  be 
Saturated ;  or  in  other  words,  the  water 
has  dissolved  all  the  salt  it  can  under 
given  conditions.  If  any  more  salt  is 
thrown  into  such  a  solution  it  will  simply 
fall  to  the  bottom  and  form  a  layer  which, 
no  matter  how  thick,  does  not  increase  the 
amount  dissolved. 

EXPERIMENT  NO.  64— 

Take  100  cc.  of  water  and  saturate  it 
with  sugar  at  20°.  It  will  take  up  200 
grams.  Now  heat  the  liquid  to  100°  and 
dissolve  more  sugar  in  it.  It  would  prob- 
ably take  up  300  grams  additional,  but  only 
add  about  20  grams.  Allow  the  liquid  to 
again  cool  to  20°.  This  solution  must  be 
allowed  to  cool  without  any  disturbance 
and  kept  perfectly  quiet  in  a  clean  bottle; 
the  separation  of  the  extra  20  grams  of 
sugar  may  not  occur  for  a  long  time. 
This  liquid  contains  more  sugar  than  the 
saturated  solution  contains,  at  the  same 
temperature,  and  when  in  such  a  condition 
is  said  to  be  a  Super-saturated  Solution. 

Drop  a  crystal  of  sugar  into  the  above 
super-saturated  solution,  and  if  the  ex- 
periment has  been  performed  correctly,  this 
crystal  will  precipitate,  or  throw  down,  the 
extra  20  grams  of  sugar  in  crystals,  and 
the  saturated  solution  will  be  formed. 

DELIQUESCENCE  :— 

If  Potassium  Carbonat  is  exposed  to  the 
air,  it  absorbs  the  moisture  from  it,  be- 
comes damp,  and  finally  forms  a  solution. 
This,  if  substances  absorb  sufficient  mois- 
ture to  dissolve  them,  or  become  wet,  the 
name  deliquescence  is  applied  to  this  be- 
havior, and  the  substances  are  said  to  be 
Deliquescent.  Substances  which  so  absorb 
moisture  from  the  air  are  also  said  to  be 
Hygroscopic. 
EFFLORESCENCE  :— 

This  term  should  not  be  confused  with 
Effervescence,  which  is  the  escape  of  a 


gas  from  a  liquid  in  which  it  is  either 
generated  or  has  been  held  by  pressure. 

If  a  crystal  of  washing  soda  is  exposed 
to  the  air  in  a  dry  place,  it  will  lose  its 
water  of  crystallization  and  become  covered 
with  a  fine  powder.  This  is  called  Efflo- 
rescence. Copper  Sulfat  [Bluestone 
CuSOjSHsO],  retains  its  water  in  ordinary 
air  but  in  very  dry  air  it  turns  white  and 
Effloresces  rapidly. 
CRYSTALLIZATION  :— 

When  a  saturated  liquid  is  cooled  and 
the  solid  precipitates,  the  latter  is  quite 
likely  to  form  .  crystal's,  especially  if  the 
cooling  is  slow.  Evaporating  the  liquid 
from  a  saturated  solution  precipitates  the 
solid,  often  in  crystalline  form.  These 
are  crystals  from  solution.  They  may  also 
be  obtained  from  Fusion,  i.e.,  melting  a 
crystalline  substance  and  allowing  it  to 
cool  slowly.  Another  method  of  obtain- 
ing crystals  is  to  make  an  insoluble  com- 
pound in  the  usual  way,  by  mixing  two 
solutions.  Generally  precipitates  obtained 
in  this  way  are  Amorphous  or  indistinctly 
crystalline,  as  time  is  not  given  for  the 
forces  of  crystallization  to  arrange  the 
molecules  in  crystalline  form.  Crystals 
may  also  be  obtained  by  the  sublimation 
from  a  vapor.  Some  substances  do  not 
crystallize  at  all  and  are  termed  Amor- 
phous, meaning  without  crystalline  form. 
EXPERIMENT  NO.  65— 

Fill  an  evaporating  dish  half  full  of 
water,  heat  it  [using  asbestos  pad  on  tripod 
or  ring  stand  support],  and  add  to  it  alum, 
either  powdered  or  in  small  pieces,  until 
the  liquid  shows  a  tendency  to  become 
thick.  Stir  it,  and  remove  the  flame,  and 
stretch  across  the  dish  a  narrow  piece 
of  calico  or  cotton  cloth  so  that  the  middle 
portion  will  hang  in  the  solution.  Set 
aside  to  cool.  It  may  be  well  to  allow 
to  stand  a  week  before  examining.  This 
experiment  illustrates  crystallization  from 
a  supersaturated  solution. 
EXPERIMENT  NO.  66— 

Cautiously  boil  about  5  grams  of  copper 
sulfat  [CuS04],  pulverized,  in  10  cc.  of 
water  in  a  test  tube  until  it  is  dissolved. 
Then  place  the  test  tube  in  an  oblique 
position  and  let  the  liquid  cool.  It  should 
be  allowed  to  stand  for  some  time.  The 
crystals  obtained  can  be  dried  between 
filter  or  blotting  paper  and  preserved. 
This  experiment  illustrates  crystallization 
from  solution. 
EXPERIMENT  NO.  67— 

Melt  15  or  20  grams  of  brimstone  (Roll 
Sulfur)  in  a  short,  wide  test  tube.  Cover 
its  mouth  now  and  then  with  cardboard 
if  the  sulfur  should  take  fire.  After  com- 
plete fusion  let  it  stand  still  till  it  starts 
to  solidify  on  the  surface;  then  pour  off 
half  of  it  into  a  dish  of  water  and  set 
the  rest  aside  to  cool.  Examine  the  part 
in  the  water,  pulling  it  to  note  its  elas- 
ticity, etc.  When  the  part  left  in  the  tube 
is  solid,  break  the  tube  and  look  for  crys- 
tals. 

EXPERIMENT  NO.  68— 

Put  3  or  4  crystals  of  Iodine  into  a 
wide,  perfectly  dry  test  tube.  Have  a 
dry  stirring  rod  in  the  right  hand,  and 
with  the  left  hand,  hold  the  tube  contain- 
ing the  Iodine  in  the  flame  of  the  Bunsen 
burner.  As  soon  as  dense  purple  fumes 
begin  to  rise  in  the  tube,  remove  the  tube 
from  the  flame,  and  thrust  the  stirring  rod 
into  the  tube,  nearly  to  the  bottom,  be- 
ing careful  not  to  touch  the  sides  of  the 
tube  with  the  rod.  Keep  it  there  until 
the  Iodine  vapor  has  settled,  and  examine 
both  the  rod  and  tube  by  means  of  a  lens. 
This  experiment  is  the  same  as  Experi- 
ment 12  [Electrical  Experimenter,  Sep- 
tember, 1916,  issue],  and  illustrates  the  for- 
mation of  crystals  by  sublimation. 


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THE   ELECTRICAL  EXPERIMENTER 


157 


EXPERIMENT  NO.  69— 

Place  a  piece  of  Ferrous  Sulfat 
[FeSOi5H»0],  in  some  place  where  it  may 
be  exposed  on  a  piece  of  paper  for  a  week 
or  so,  after  which  time  examine  for  white 
powder.  This  experiment  illustrates  Efflo- 
rescence. 

EXPERIMENT  NO.  70— 

Expose  a  piece  of  Calcium  Chlorid 
[CaCl2]  on  a  paper  for  a  week  or  more. 
Note  any  phenomena.  This  illustrates 
Deliquescence. 

The  laws  of  precipitation  state : — 

[1]  That  when  two  substances  are  mixed 
in  solution,  a  new  compound  can  be  formed 
that  is  insoluble  in  the  solvent  employed, 
such  compound  will  be  formed  and  will 
appear  as  a  precipitate. 

[2]  When,  on  mixing  different  sub- 
stances, a  new  substance  that  is  volative 
can  be  produced  by  the  rearrangement  of 
the  atoms  of  the  partaking  substances, 
such  new  substance  will  be  produced  and 
will  appear  as  a  gas. 

EXPERIMENT  NO.  71— 

Suppose  we  wish  to  prepare  Silver 
Chlorid  [AgCl|.  We  know  that  this  com- 
pound is  insoluble.  Therefore  we  must 
select  a  soluble  salt  of  silver,  and  also 
a  soluble  chlorid.  Silver  Nitrat  [AgN03] 
being  the  only  soluble  silver  salt  in  com- 
mon use,  we  make  a  solution  of  it.  We 
may  also  take  most  any  chlorid,  because 
they  are  mostly  all  soluble.  Sodium 
Chlorid  [common  table  salt]  being  one 
of  the  cheapest,  we  shall  use  it.  Take  a 
little  Sodium  Chlorid  and  dissolve  it  in 
water.  Pour  one  of  the  solutions  into 
the  tube  containing  the  other,  and  the 
precipitat  of  silver  chlorid  which  we  wanted 
is  thus  obtained.  Save  the  precipitat  for 
the  next  experiment.  This  experiment  also 
illustrates  a  substance  which  is  insoluble  in 
water. 

EXPERIMENT  NO.  72— 

Prepare  some  Silver  Chlorid  [AgCl]  as 
in  Experiment  71,  taking  not  over  5  cc.  of 
each  solution  and  using  for  one  the  silver 
salt  prepared.  Let  the  Silver  Chlorid  sub- 
side and  pour  off  the  upper  supernatant 
portion  of  the  liquid,  leaving  the  solid 
with  some  liquid.  Add  a  little  Ammonium 
Hydroxid  [NPLOH],  cover  the  mouth  of 
the  tube  with  the  thumb,  and  shake  well. 
If  the  solid  does  not  all  disappear,  add 
more  Ammonium  Hydroxid.  Upon  the 
addition  of  Ammonium  Hydroxid,  the  pre- 
cipitat should  lie  dissolved  and  a  clear 
translucent  solution  formed.  Thus  we 
have  prepared  a  solid  from  two  clear 
liquids,  and  then  dissolved  the  solid  with 
another  liquid.  This  experiment  shows  that 
substances  which  are  insoluble  in  water, 
are  made  soluble  in  various  other  liquids. 
(To  be  continued.) 


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Experimenter,  published  monthly  at  New  York, 
N.  Y.,  for  April  1,  1917. 

State  of  New  York,  County  of  New  York,  ss. 

Before  me,  a  Notary  Public  in  and  for  the  State 
and  county  aforesaid,  personally  appeared  Hugo 
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and  Regulations,  to  wit: 

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Hugo  Gernsback,  233  Fulton  St.,  New  York  City.; 
Managing  Editor,  Hugo  Gernsback,  233  Fulton  St., 
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City;  Hugo  Gernsback,  233  Fulton  St.,  New  York 
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or  corporation  has  any  interest  direct  or  indirect 
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H.  GERNSBACK,  Editor. 
Sworn  to  and  subscribed  before  me  this  16th 
day  of  April,  1917. 

(Seal.)  E.  D.  JUNIOR. 

(My  commission  expires  March  30,  1919.) 

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catalogue  showing  a  complete  line  of  Electrical 
Motors  and  Novelties  ranging  in  price  from  10c  up. 

KNAPP  ELECTRIC  &  NOVELTY  CO. 
523  West  51st  Street,  N.  Y.  City 


Electric  Row  Boat  Motor 

Makeyour  Row  Boat 
an    Electric  Launch. 
Buy  a  Jewel  Detachable 
Row  Boat  Motor  run  by 
electricity.   No  odor  or 
dangerous  gasoline. 
.Simple,  noiseless 
and  powerful. 
Attaches  to  any 
Row  Boat  and 
runs  on  two  six 
Batteries.  This  is  our  5th 
successful  year. 

OPEN  WINDOW  BATTERY 

Look  inside  your  storage  battery  through  the 
patented  open  window.  See  condition  of 
plates  and  height  of  electrolyte.  If  you  need  a 
new  automobile  starting  Battery  buy  a  Jewel 
and  save  money.     6-00  Special  S8.50. 

Motorcycle  Electric  Lighting  System 
The  Jewel  Generator  Motorcycle  Storage  Battery  and 
complete  lighting  system  is  in  great  demand.  Agents 

wanted.     Write  fo  r  prices  and  catalog  E. 

JEWEL  ELECTRIC  COMPANY,  112  N.  Fifth  Av.,  CHICAGO 


STROMBERC  ■  CARLSON  <CQ  25 
RADIO    HEAD  SET   

Stromberg  -  Carlson    Telephone    Mfgi  Co. 
Rochester,   N.  Y. 


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^  /  ?   9  " 

free  iivkou ! 


Read  iki*  Ft  maikahk  Offei'i 


This  masterpiece  contains  160  pages,  400  illustrations.  Size 
of  book  5"  x  9".    Printed  on  extra  thin  paper,  so  book  can 
be  slipped  in  pocket.    Handsome  stiff  cloth  cover. 
Price  $1.00  if  bought  alone.  FREE  with  a  year's  subscription. 


The  most  comprehensive  Wireless  Course  ever  printed.  Con- 
tains 160  pages,  350  illustrations.  Size  of  book  6}$f  x9Jf 
Very  fine  flexible  linen  cover. 

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ip  ^Electrica 
5  Experimenter  ZL 


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they  are  gone  we  cannot  reprint  the  books  until  conditions  become  normal  again. 
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more  than  1 00  cents*  worth  for  each  dollar  spent  with  them.  Profit  by  this  liberal 
opportunity  NOW;  it  may  never  be  made  again. 


5      HERE'S  THE  OFFER 

Subscribe  to  THE  ELECTRICAL  EXPERIMENTER  for  one  year,  at 
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eign $2.00)  and  we  will  send  you  FREE  POSTPAID,  either  one  of 
the  above  books.  If  you  subscribe  for  two  years,  BOTH  BOOKS 
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6-17 


LIGHTN! 
MADE  TO  OKDEK 


12  copies  of  THE  ELECTRICAL  EXPERI- 
MENTER make  a  book  9"  x  12"and4"  thick. 
This  book  will  weigh  7  lbs.     1 1  is  the  greatest 
Electrical    and    Wireless  reference 
work  in  the  world.    And  all  for  y*»OU 


If  you  are  a  subscriber  at  present,  take  advantage  of  this 
wonderful  opportunity  anyway.  If  you  do,  we  will  extend 
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my  subscription 
//       to  THE  ELEC- 
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'\,'       MENTER  for  the 

y_  V4'        term  of  year  

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with $  

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FREE  prepaid  your  book.. . 


5v 


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June,  1917  THE  ELECTRICAL  EXPERIMENTER  159 


Scientific  Exchange  Columns 

UNDOUBTEDLY  you  have  at  the  present  time  some  things  for  which  you  have  no  further  use.  Do  you  ■wish  tor  exchange  them  for  something, 
for  which  you  have  immediate  use?  There  is  no  surer  and  quicker  way  to  do  this  than,  by  advertising  your  articles  in  these  columns. 
The  very  people,  the  Only  people,  who  could  possibly  have  a  use  for  your  things  read  this  journal.  More  than  75,000  interested  people 
will  see  your  ad.  It  is  furthermore  the  cheapest  advertising  medium  for  you  in  the  country.  Dealers'  advertising  accepted  in  Opportunity 
Exchange  Columns  only. 

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OVER  75,000  PEOPLE  READ  THIS  JOURNAL 


fee 


fa 


STOP!  LOOK! 
54"  Spark  Coil,  $1.50;  large  accurate  Voltam- 
meter,  $3;  large  Static  Machine,  17"  plates,  oper- 
ates large  X-Ray  tubes,  worth  $40,  for  $15;  Load- 
ing Coil,  $1.25.  All  rest  E.  I.  goods.  $1.25  Fixed 
Variable  Condenser,  75c;  $2.  Rotary  Potentio- 
meter, $1.10;  2,000  ohm  headset,  $3.  Call  or 
write,  all  answered.  Satisfaction  guaranteed.  C. 
Krummenacker,  1034  73rd  St.,  Brooklyn,  N.  Y. 

WANTED — Tents,  Scouting  and  Gym  supplies. 
Have  Wireless  Instruments  to  swap.  Dean  Wil- 
son, Alpha,  111. 

FOR  SALE — Receiving  Set,  consists  Arlington 
Coupler,  H-C  3000  ohm  Phones,  Murdock  Con- 
denser, Perikon  Detector,  Switches  and  large 
quantity  Crystals.  All  new.  Only  $14.  J.  Smith, 
Trout  Run,  Pa. 

FOR  SALE — One  Junior  Cyclecar  at  $65.  A 
bargain.     Jacob  Rau,   Bathgate,   N.  D. 

MOTORCYCLE— Thor,    clutch,     chain  drive, 

food  tires,  fine  running  order,  $45.  Also  parts 
or  cyclecar,  twin  engine  with  magneto,  wheels, 
etc.,  cheap.  L.  H.  Murdock,  3315  Stettinius, 
Hyde  Park,   Cincinnati,  Ohio. 

WANT  TO  TRADE— Bicycle  and  wireless 
goods,  for  motorcycle  in  running  order.  All  let- 
ters answered.    Roy  Phillips,  Hartford,  Michigan. 

WANTED — Trade  foot-power  lathe.  Post  drill, 
25-20  Mailin  pump  rifle  for  wireless  goods.  Write 
for  particulars  and  state  what  you  have  to  sell 
or  trade.    Lee  Jones,  706  Lillmore,  Amaillo,  Texas. 

FOR  SALE — Amateur  receiving  set,  good  con- 
dition.    Write  Dock  Stuart,  Troy,  N.  C. 

"WANTED— Battery  Rotary  2-inch  Spark  Coil, 
for  instruments  I  have.  Write  for  list.  August 
Otta,  Moweaqua,  111. 

WANTED — Omnigraph  and  dials.  Also 
"Smith"  Flyer  or  motor  wheel.  Must  be  cheap. 
Cash  only.    E.  Wilson,  Gwynedd  Valley,  Pa. 

FOR  SALE— Two  3  'AxS'A  film  cameras. 
Ansco,  $10;  Eastman,  $6.  Smith  Premier  Type- 
writer, $15.  Automobile  magneto,  $5.  Dynamo- 
motor,  $1.50.     Lawrence  Johnston,   Fairfield,  111. 

QUICK— FOR  SALE— Oscillation  transformer, 
regenerative  set,  navy  type  coupler,  audion  panel, 
storage  battery.  Extremely  low  prices.  Lester 
Fawcett,  Independence,  Iowa. 

AUDION  and  Amplifier  cabinet  set,  including 
tuning  equipment,  $50.  Atidion  detector  broken 
bulb,  $8.  Want  Blitzen  coupler;  pair  undamped 
coupler  coils,  $2.50.  McMurdo  Silver,  264  West 
57th  St.,  New  York  City. 

FOR  SALE — >4  H.P.  2  Cycle  Engine,  $12. 
12  volt  8  ampere  generator,  $8;  physicians  micro- 
scope, Baush  and  Lomb  make,  $20;  cost  $65. 
B.   Roehling,  3705   N.   Hermitage  Ave.,  Chicago, 

FOR  SALE — A  first-class  violin  and  bow  (less 
bridge  and  strings)  A-l  condition.  Cost  $20, 
sell  for  $15.    Marcus  Harbs,  Wilton,  Conn. 

OMNIGRAPH  WANTED— Will  pay  cash  for 
Omnigraph  in  first-class  condition.  B.  Cochran, 
Box  55,  Palmetto,  Georgia. 

FOR  SALE— 200  watt  transformer.  Steps  110 
to  10,  20,  30  or  40  volts,  $10;  40  watt  dynamo  or 
1/12  H.P.  motor,  $7;  Inch  spark  coil;  fine  fat 
spark,  $4;  Testing  magneto,  $2.50;  20  ohm  sensi- 
tive pony  relay,  $1.50;  20  ohm  giant  sounder  and 
steel  key,  $2.50;  Portable  Voltmeter,  1-20  range, 
$1.50;  Filings  coherer,  $1;  75  ohm  wireless  re- 
ceiver with  headband,  $1.25;  1/12  H.P.  water 
motor,  $1.50.    C.  M.  Adams,  Milford,  Ohio. 

SELL — 40  lesson  Taxidermy  Course,  $9.  Trade 
3  yrs.  Youth's  Companions  for  Al,  2  slide  tuner. 
William  Litwiller,  Hopedale,  111. 


FOR  SALE— Silicon  Detector  without  cat 
whisker  wire,  50c;  1,000  ohm  Receiver,  75c; 
Galvanometer,  25c;  Telegraph  Set,  50c;  Leather- 
covered  headband,  50c.  Remittance  must  accom- 
pany order.     Write  Harry   Layman,  Davidsville, 


UKULELE — Koa  wood,  $10,  or  trade  for 
camera.  Give  size,  lens,  style,  make,  etc.,  or 
guitar.    Clyde  B.  Marx,  Kaskela,  Oregon. 

FOR  SALE— Otis  Clapp  Static  Machine  in  first- 
class  condition.  Two  19"  plates  on  hand  operated 
end.  Ten  29"  plates  on  power  operated  end. 
Several  Leyden  jars  and  various  discharging  de- 
vices to  go  with  machine.  Cabinet  measures 
66"x66"x30  wide.  All  enclosed  in  glass,  $75, 
f.o.b.  Mattapan,  Mass.  Cost  $450.  Fritz  Henrici, 
Mattapan,  Mass. 


|IJi 


TALK  ABOUT  RESULTS ! 

17  PRYER  LANE, 
Larchmont  Manor,  N.  Y. 

The  Experimenter  Pub.  Co. 
New  York  City 

Dear  Sir: — 

Talk  about  results!  You've 
got  to  give  it  to  the  "E.  E."' 
to  reach  the  right  people.  On 
the  day  after  "E.  E."  came 
out  I  received  a  reply  and 
they  have  been  coming  in  at 
the  rate  of  one  a  day.  If  I 
ever  have  anything  else  that 
I  want  to  sell  I  will  send  my 
"ad"  to  you  every  time. 
Yours  truly, 

Clarence  de  Witt  Rogers,  Jr, 


! 


BARGAINS — Leaving  home,  must  sell.  New 
Electron  Relay,  $3;  slightly  used,  $2.  Loose  Coup- 
ler, $1.  500  volt  D.  C.  1/3  horsepower  Holtzer 
Cabot  motor  and  rheostat  equal  to  new,  $15. 
D.  P.  1,000  ohm  phone,  headband,  cord,  $1.25. 
Electrolytic  detector,  75c.  Telephone  magnetos, 
solid  armature,  50c,  laminated,  $1.  $10  Remy  6 
volt  automobile  magneto,  good  condition,  $3.  Six- 
inch  parabolic  reflector,  50c;  new  bulbs,  20c. 
High  resistance  ringer  coils,  15c  each;  telephone 
transmitters,  50c;  receivers,  50c;  induction  coils, 
20c;  y2  lb.  22  German  Silver  wire,  35c;  2  lb. 
antenium  wire,  40c;  quantity  2  strand  steel  guy 
wire  cheap.  Premo  Junior  No.  2  Camera,  new, 
$1.  Mechanical,  electrical  magazines  cheap.  Pre- 
paid except  magnetos,  motor,  wire.  Stamps  or 
money  order,  or  write  for  further  information. 
Kenneth  Bard,  Manawa,  Wis- 


EXCHANGE — Complete  set  of  parts  for  a  Ford 
engine,  with  exception  of  crank  shaft  and  flywheel 
for  a  panel  type  receiving  set,  typewriter  or  wire- 
less supplies.  J.  Yates  Van  Antwerp,  35  South 
Perry  St.,  Johnstown,  N.  Y. 

SALE  OR  EXCHANGE— B-Flat  cornet,  $12; 
shotgun,  $3;  incubator,  $3.  John  Enos,  Wellneet, 
Mass. 

FOR  SALE— 1/,  H.P.  Gas  Engine,  500  watt  110 
volt  "D.C.  Generator,  small  lathe,  'A  H.P.  110 
volt  D.C.  motor,  Jeweler's  Foot  Wheel.  Write 
for  description.  J.  H.  Clemmer,  Blue  Creek,  W. 
Va. 

FOR  SALE— Motor,  $10;  Headset,  $4;  1-inch 
Coil,  $3;  a  Potentiometer,  $3;  Detector,  $2;  Spark 
Cap,  $1;  Sending  Condenser,  $2.  Paulding,  Can- 
terbury   School,    New   Milford,  Conn.  

FOR  SALE— Alternating  Current  Electric 
Sewing  Machine  Motor,  $15;  new  condition;  cost 
$30.  H.  N.  Richmond,  1628  Washington  Ave., 
Colorado  Springs,  Colo. 

WANTED — Second-hand  generator  suitable  for 
charging  storage  batteries.  Must  be  in  first-class 
condition.     Archie  E.  Banks,  Delmar,  Va.  

FOR  SALE— 5,000  mile  Audion  Receiving  Set, 
complete,  $40.  George  Leonard,  11  Hamlet  St., 
Uphams  Corner,  Mass. 

EXCHANGE — 6  volt,  %  horse-power  motor; 
110  volt,  1/16  horse-power  motor,  110  volt 
ammeter.  Want  audion,  1  K.W.  quenched  gap,  or 
other  apparatus.  Ira  Wright,  Closson  St.,  Me- 
thuen,  Mass. 

FOR  SALE  OR  EXCHANGE — 28  ft.  Curtiss 
aeroplane,  without  motor;  crated;  will  sell  ch  ap; 
want  $100  cash.  Make  offer.  V.  G.  Gustafson, 
Joliet,  111.  

HAVE — Oliver  Typewriter,  Model  3.  Want 
cash  or  receiving  apparatus.  Make  offer.  All  let- 
ters answered.  Herbert  Richter,  Collegeville, 
Minn.  

BARGAIN — Complete  new  Blitzen  Receiving 
set  with  extra  equipment.  Holtzer-Cabot  Phones. 
In  perfect  condition.  Write  for  particulars.  Chas. 
Bayhss,  68  Peterboro  St.,  Detroit,  Mich. 

FOR  SALE — Complete  Audio-Tron  on  panel 
with  all  controls  and  4-40  storage  battery.  Panel 
has  2  D.P.D.T.  mineral  change-over  switches 
wired  on.  Used  10  hours.  $10.  Also  "Arlington" 
4,000  M.  Coupler,  cost  $9,  for  $6.60  and  $4. 
Murdock  Oscillation  for  $3.  George  R.  Ham- 
mond, Oelwein,  Iowa. 

WILL  EXCHANGE  my  Twin-Cylinder,  6  H.P. 

Merkle  motorcycle,  in  perfect  condition,  for  good 

wireless  apparatus.  Francis  Joannini,  3326  17th 
St.,  Washington,  D.  C. 

FOR  SALE— Set  Cyclopedia  of  Applied  Elec- 
tricity.  Send  for  description.  All  letters  an- 
swered. J.  N.  Boyington,  South  Galena  Ave., 
Freeport,  111.  

FOR  SALE — Three  undamped  wave  loading 
coils  less  sliders,  $5.  Brand  new  Chambers  No. 
749  loose  coupler,  bargain.  Write  H.  A.  Guenzel, 
410  Buttonwood  St.,  Philadelphia,  Pa.  

WANTED— Brandes  or  Murdock  2000  ohm 
headset  for  $3.  A.  Taylor,  105  East  102nd  St., 
New  York. 

WILL  EXCHANGE  first-class  wireless  set  for 
"Smith"  motor  wheel,  or  Motorcycle.  Bernard 
Brown,  Troy,  N.  C.  

SLIGHTLY  used  printer's  type  for  sale  cheap. 
Geo.   Wasserberger,  Neillsville,  Wis. 

$75  Chicago  University  advertising  course,  _  6 
volumes  with  questions  for  sale  for  $8  Write 
if  interested.    Geo.  Wasserberger,  Neillsville,  Wis. 

FOR  EXCHANGE— Keystone  MilH-voltmeter, 
excellent  for  research  work  and  radio  measure- 
ments. Will  accept  either  small  110  V.  60  cycle 
A.C.  motor,  opera  glasses,  or  «*hat  have  vou? 
Samuel  Cohen,  1936  Pitkin  Ave.,  Brooklyn,  N.  Y. 


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160 


THE  ELECTRICAL  EXPERIMENTER 


June,  1917 


Opportunity  Exchange 


'VrOU  will  probably  find  more  opportunities  and  real  bargains  in  these  columns  than  anywhere  else  in. the  country.  Most  good  things  in 
~  life  are  hard  to  find  and  worth  going  after — these  little  ads  illustrate  that  point;  you  alone  will  be  the  real  loser  if  you  don't  take  the 
time  to  scan  through  these  columns. 

Advertisements  in  th.s  section  4c.  a  word  for  each  insertion.     Count  7  words  per  line. 

Name  and  address  must  be  included  at  the  above  rate.  Cash  should  accompany  all  classified  advertisements  unless  placed  by  an  accredited 
advertising  agency. 

Ten  per  cent,  discount  for  6  issues,  20  per  cent,  discount  for  12  issues  from  above  rate.  Objectionable  or  misleading  advertisements  not 
accepted. 

Advertisements  for  the  July  issue  should  reach  us  not  later  than  May  25. 

OVER  75,000  PEOPLE  READ  THIS  JOURNAL 

EXPERIMENTER  PUBLISHING  CO.,  INC.,  233  Fulton  Street,  New  York,  X.  Y. 


4 


BOOKS 


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401   Caxton   Bldg.,   Cleveland,  Ohio,  

"BOOK  OF  KNOWLEDGE"— An  interesting 
book  revealing  valuable  trade  secrets,  new  and 
scientific  discoveries  and  old  mysteries.  Send  25c 
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DO  YOU  WANT  back  numbers  of  THE  ELEC- 
TRICAL EXPERIMENTER?  Send  for  bound 
volume  No.  3,  containing  issues  from  May,  1915, 
to  April,  1916.  Price,  $1.25.  Postage  on  7  lbs. 
is  extra.  Experimenter  Pub.  Co.,  233  Fulton  St., 
New  York  City.  

BOOKS — Scientific  and  wireless  supplied.  Let 
us  l»iow  what  you  want  and  we  will  quote  you. 
Experimenter  Pub.  Co.,  233  Fulton  St.,  New  York 
City. 

A  BINDER  for  THE  ELECTRICAL  EXPERI- 
MENTER will  preserve  your  copies  for  all  time. 
Price,  50c.  Postage  on  3  lbs.  is  extra.  Send  for 
one  today.  Experimenter  Pub.  Co.,  233  Fulton 
St.,  New"  York  City. 

CHEMICALS 

CHEMICALS  FREE  for  growing  chemical 
plants.  To  introduce  our  chemicals  and  appara- 
tus to  Experimenters,  we  will  send  free,  the  neces- 
sary chemicals  to  grow  trees,  grass,  etc.  Send 
10c  coin  (refund  on  first  order)  for  postage  and 
catalogue.  Zenith  Chemical  Laboratories,  307 
West  Second  St.,  Duluth,  Minn. 

CHEMICAL  EXPERIMENTERS!! 
I   can    supply    you    with    any    chemical  known, 
in  any  quantity,  dirt  cheap.    Also  formulas.  Write 
for  price  list.     The  Swimmer  Chemical  Co.,  1904 
Park  Place,  Brooklyn,  N.  Y. 

EXPERIMENTERS— Are  you  interested  in 
novel  chemical  experiments?  Send  10c  for  large 
collection.    Merel  Sager,  44  Apple  St.,  Tiffin,  Ohio. 

HELP  WANTED 

THOUSANDS  MEN,  WOMEN— 18  or  over, 
WANTED  for  U.  S.  Government  jobs.  $75.00 
to  $150  month.  War  means  many  vacancies. 
Steady  work;  short  hours;  rapid  advancement. 
Common  education  sufficient.  Write  immediately 
for  list  of  positions  now  obtainable.  Franklin 
Institute,  Dept.  C  27,  Rochester,  N.  Y. 

MISCELLANEOUS 

ELECTRICIANS— Send  50c  for  10  Blue  Prints 
of  Motor  and  Generator  Connections.  28  for 
$1,  10  A.  C,  4  D.  C.  Motor  Winding  Diagrams 
for  $1  or  20  A.  C,  4  D.  C,  and  4  Rotary  Con- 
verter Drawings,  $1.60.  Winding  made  easy. 
Martin  Electric  Co.,  329  Irvington  PI.,  Denver, 
Colo. 

WORN  OUT  DRY  BATTERIES  CAN  BX 
RECHARGED  for  less  than  one  cent.  Send 
twenty  cents  for  formula  to  E.  Bohner,  1009 
South  Wabash,  Chicago. 

WE  WANT  HUSTLERS  to  handle  fast  sell- 
ing household  necessities.  Big  profits,  beautiful 
premiums,  free  particulars.  Variety  Supply,  21 
East  St.,  Providence.  R.  I. 

FOR  SALE — Cameras,  400  Exposure  Kodak 
with  stereopticon  enlarger;  cost  $56;  sell  for  $30. 
One  5x7  Seneca  folding  camera,  3  plate  holders, 
tripod,  carrying  case,  etc.,  cost  $2,  $2.50,  sell  for 
$12.  One  4x5  magazine  camera,  aluminum  plate 
holders,  carrying  case,  etc.,  cost  $15,  sell  for  $6. 
V.  G.  Gustafson,  Joliet,  111. 

ATTENTION ! 
Secret    ink;    invisible    when    written,    and  can 
only  be  seen  by  our  special  process.     Price  10c. 
The  Swimmer  Chemical  Co.,  1904  Park  PI.,  Brook- 
lyn, N.  Y. 


BOYS! — Funny  blotters,  10c  per  bunch.  Other 
samples  included  with  order,  with  wholesale 
prices.  The  Novelty  Distributing  Agency,  Box 
382,  Marshalltown,  Iowa. 

CASH  YOUR  SPARE  TIME  INTO  MONEY. 
One  young  man  made  $1,800.00  in  two  months. 
Sells  to  every  automobile  and  motorcycle  owner. 
Representatives  wanted  everywhere.  Be  first  in 
your  territory — write  quick  for  free  sample  and 
particulars.  Everhold  Fabric  Patch  Co.,  Chanute, 
Kansas. 

FOR  SALE— Tents,  one  40x80  ft.,  round  top, 
four  20  ft.  center  poles,  9  ft.  wall;  bargain;  $90. 
One  16x24  ft.  hip  roof,  square  end,  7  ft.  khaki 
drill  wall,  $20.  One  12x19  ft.  square  end,  6  ft. 
8  in.  wall,  $14.  All  tents  complete  ready  to  set 
up.    V.  G.  Gustafson,  Joliet,  111. 

BARGAINS — Selling  out  music.  Over  $3 
value  for  $1.  Sample  10c.  B.  Scholz,  Majestic 
Theatre  Co.,  Sheboygan,  Wise. 

EVERYBODY  WANTS  IT — Eolding  Pocket 
Coat  and  Hat  Holder.  Can  attach  anywhere  and 
remove  instantly,  nickel  plated.  Sample  10c.  Big 
seller  for  agents.  Wedge  Mfg.  Co.,  "Km"  Bing- 
hamton,  N.  Y. 

25c  Diminishing  card  trick,  apparatus  included 
for  5c,  just  to  introduce  big  free  catalog.  Aladdin, 
Neillsville,  Wis. 

WANTED — Second-hand  drafting  instruments. 
Highest  prices  paid.  Send  complete  description 
and  we  will  make  offer.  Deutsch,  2358  Pitkin 
Ave.,  Brooklyn,  N.  Y. 

MARCONI — We  have  a  limited  number  of 
pictures  of  Guglielmo  Marconi,  Nikola  Tesla  and 
Charles  P.  Steinmetz  that  are  done  in  sepia  on 
fine  India  paper.  Fine  for  decorating  your  wire- 
less room.  10c  each  postpaid.  Experimenter 
Publishing  Co.,  233   Fulton  St.,   New  York  City. 

PATENT  ATTORNEYS 

PATENTS— R.  Morgan  Elliott  &  Co.,  Patent 
Attorneys,  Mechanical,  Electrical  and  Chemical 
Experts,  716-724  Woodward  Bldg.,  Washington, 
D.  C. 


151  LAKE  AVE., 

Lancaster,   X*.  Y. 

Feb.  22,  1917. 

Gentlemen  : 

I  wish  to  tell  you  that  my  ad.  in 
the  E.  E.  was  a  great  success,  and 
exceeded  all  expectations.  I  had  re- 
plies before  I  had  received  a  copy  of 
the  issue  myself.  This  goes  to  show 
that  every  issue  is  looked  for  with 
great  interest,  and  the  wide  field  your 
paper  covers.  I  certainly  will  recom- 
mend it  to  the  amateurs  that  have 
something  to  trade  or  sell. 

Yours  respectfully, 

G.  W.  Bradford. 


IDEAS  WANTED— Manufacturers  are  writing 
for  patents  procured  through  me.  Four  books 
with  list  hundreds  of  inventions  wanted,  sent 
free.  I  help  you  market  your  invention.  Advice 
Free^    R.  B.  Owen,  130  Owen  Bldg.,  Washington, 

PATENTS  ON  EASY  PAYMENTS— Send 
model  or  sketch  for  Free  Search  and  Certified 
Registration  of  your  Invention  for  your  Pro- 
tection. Free  book  tells  what  to  invent  and  how 
to  obtain  a  patent  on  easy  payments.  C.  C.  Hines 
&    Co.,    593    Loan    &    Trust    Bldg.,  Washington, 

PATENTS — Without  advance  attorney's  fees. 
Not  due  until  patent  allowed.  Send  sketch  for 
free  report.  Books  free.  Frank  Fuller,  Washing- 
ton, D.  C. 


 PHONOGRAPHS 

BUILD  YOUR  OWN  PHONOGRAPH  or 
manufacture  them  for  profit.  Drawings,  instruc- 
tions, etc.,  twenty-five  cents.  Satisfaction  guar- 
anteed. Circular  free.  Associated  Phonograph 
Co.,  Dept.  E.,  Cincinnati. 


STAMPS— COINS— CURIOS 

50,000  coins,  medals,  notes,  Indian  relics;  35,- 
000  antique  firearms,  daggers.  Catalogue,  4c. 
Antique  Shop,  33  South  18th  St.,  Philadelphia. 

STAMPS— 75,  all  different,  free.  Postage  2c. 
Mention  paper.    Quaker  Stamp  Co.,  Toledo,  Ohio. 


WIRELESS 

ELECTRON  RELAYS,  Moorhead  tubes,  Len- 
zite  detectors,  Racine  motors.  Authorized  repre- 
sentative. S.  &  T.  Sales  Co.,  69  Freeman  Ave., 
East  Orange,  New  Jersey. 

FOR  SALE— $35  R.A.-6,  $28.  Special  $42.50 
R.A.-6,  genuine  polished  mahogany  Formica  panel, 
$33.  $15,  3,000  meter  coupler,  $9.75.  Regener- 
ative panel  with  vacuum  bulb,  variometer,  con- 
densers, rheostat,  etc.,  $14.  1,000  meter  coupler, 
special  for  above  panel,  $5.  5,000  meter  loading 
coil,  switch  and  12  points  on  hard  rubber  panel 
to  be  used  with  above  coupler,  $5.  All  above 
high  grade,  brand  new  instruments.  Also  one 
used  electron  relay  cabinet,  damped  andjundamped 
hookup  with  bulb,  $8.    V.  G.  Gustafson,  Joliet,  111. 

FOR  SALE — To  dispose  of  the  following  in- 
struments, I  am  offering  same  far  below  the  orig- 
inal cost.  Three  sections,  Murdock  Moulded  Con- 
densers, $4.  One  K.  W.  Oscillation  Transformer, 
$4.  Sayville  Rotary  Spark  Gap,  $9.  E.  I.  Co., 
Transatlantic  Phones  (2,000  ohms)  $4.  The 
above-mentioned  instruments  are  in  first-class  con- 
dition. If  interested,  write  for  particulars. 
Charles  W.  Havlena,  934  18th  Ave.,  E.,  Cedar 
Rapids,  Iowa. 

AMATEUR  BENCH  LATHE— Austin  make, 
8"  between  centers,  3  speed  pulley,  very  strong, 
neat  and  efficient.  Price  only  $3,  worth  double. 
Limited  supply  on  hand.  Louis  E.  Schwab,  3708 
Brooklyn  Ave.,  Cleveland,  Ohio. 

WANTED— One  K.  W.— Have  Willard  Storage 
Batteries  to  exchange.  Large  Tesla  and  Oudin 
coils,  $3.24  and  $2.75.  Panel  loose  coupler,  $4.25, 
etc.  Telephone  ringers,  60c;  coils,  3  for  25c. 
Stamp  for  pictures.  Garden  City  Radio  Club, 
Garden   City,  Kansas. 

COILS!  COILS!  COILS! 
54"  spark  coils,  excellent  condition,  $1.50.  Sat- 
.    isfaction    guaranteed.      Jacob    Eisgran,    1520  St. 
I    Marks  Ave.,  Brooklyn,  N.  Y. 


You  benefit  by  mentioning  "The  Electrical  Experimenter"  when  writing  to  advertisers. 


FIVE  minutes  of  actual  practice 
properly  directed  is  worth  more  to 
a  man  than  years  and  years  of  book 
study.  Indeed.  Actual  Practice  is  the 
only  training  of  value,  and  graduates  of 
New  York  Electrical  School  have  proved 
themselves  to  he  the  only  men  that  are 
fully  qualified  to  satisfy  EVERY  de- 
mand of  the  Electrical  Profession. 

At  this  "Learn  by  Doing"  School  a  man 
acquires  the  art  of  Electrical  Drafting;  the  best 
business  method  and  experience  in  Electrical 
Contracting,  together  with  the  skill  to  install, 
operate  and  maintain  all  svstems  for  producing, 
transmitting  and  using  electricity.  A  school 
for  Old  and  Young.    Individual  instruction. 

Letters  from  Successful 
Men 

"I  have  done  well  since  leaving  school  and 
am  now  Superintendent  of  the  light,  telephone 
and  steam  heat  company  here." 

"Beginning  last  April,  extensions  to  the  plant 
called  for  an  additional  equipment  of  300  kw., 
so  I  prepared  plans  and  specifications  for  a 
600  kw.  sub-station — looked  after  the  erection 
of  the  budding  and  then  installed  the  equip- 
ment. The  cost  of  the  equipment  was  $6,200. 
This  plant  has  been  in  operation  for  several 
months — without  a  hitch — and  for  its  size  is 
the  best  sub-station  in  the  camp. 

"I  am  now  preparing  plans  for  another  station 
of  the  same  size,  for  the  North  Thompson 
Mines,  with  which  this  property  (Vipond)  has 
lately  been  consolidated.  The  equipment  of 
this  property  inside  of  a  year  probably  wdl  be 
1,000  to  1,200  kw.,  etc.,  etc. 

"I  hope  this  resume  of  my  work  has  not  been 
too  lengthy.  During  this  year  I  acquired  a 
wife  and  home.    With  best  wishes  to  all." 

"I  have  a  friend  that  is  pointing  for  a  degree 
in  Electrical  Engineering,  and  I  have  advised 
him  that  he  is  making  a  mistake  when  he  con- 
siders anything  other  than  the  course  given  by 
the  N.  Y.  E.  S.    Best  wishes  for  the  school.' 

"As  this  card  indicates  I  arrived  here  in 
Petrograd,  safe  and  sound.  Censorship  forbids 
mentioning  the  work  that  I  am  doing  for  the 
Government,  but  of  course  you  can  guess  what 
it  is.    Regards  to  the  instructors." 

"Am  in  Central  Station  work,  and  am  man- 
ager of  the  local  svstem.  I  took  charge  June, 
1013.  I  started  at  $90.00  but  at  present  am 
pulling  down  $150.00  with  another  substantial 
advance  in  sight." 

New  York  the  Center 

We  are  located  in  the  heart  of  New  York 
City  and  you  can  see  the  advantage  of  that. 
New  York  is  the  heart  of  everything  electrical 
— there  are  big  plants  nearby,  electrical  exposi- 
tions, libraries  and  facilities  for  good,  quick 
work  in  an  atmosphere  of  industry. 

A  large  number  of  our  students  come  from 
other  cities,  from  all  over  the  United  States. 
They  realize  the  advantage  of  coming  to  New 
York  to  learn  electricity.  About  4,500  in  all 
have  gone  out  from  our  school  into  success. 
You  can  do  the  same.  We  believe  that  with 
us  von  can  learn  more  thoroughly  and  more 
quicklv  than  anywhere  else  because  we  give 
von  fractice.      We  teach  you  only  what  you 


And  Now 


If  you  have  an  ambition  to  make  a  name 
for  yourself  in  the  electrical  field  you  will 
want  to  join  the  New  York  Electrical  School. 
It  will  be  an  advantage  to  you  to  start  at  once. 
Then  you  should  hurry  to  send  for  our  64- 
page  book  which  tells  you  all  about  the  school, 
with  pictures  of  our  equipment  and  students 
at  work,  and  a  full  description  of  the  course. 
S'ou  need  not  hesitate  to  send  for  this  book. 
It  is  FREE  to  everyone  interested  in  electricity. 
It  will  not  obligate  you  to  send  for  it.  Send 
the  coupon  or  write  us  a  letter.  But  write  us 
now  while  you  are  thinking  about  the  subject 
of  electricity. 

School  open  to  visitors  9  A.  M.  to  9  P.  M. 


NEW  YORK  ELECTRICAL  SCHOOL 
29  WEST  171*  ST., 

NEW  YORK,  N.Y. 


I 
I 

I 

J 


New  York  Electrical  School 

29  W.  17th  St.,  New  York,  N.  Y. 

Please  send  FREE  and  without  obligation  to  me  your  64-page  book 

NAME   

ADDRESS   


You  benefit  by  mentioning  '■The  Electrical  Experimenter"  when  writing  to  advertisers. 


Succeed  Through  Electricity 


This  is  the  Electrical  age. 
Electricity  now  controls  more 
trades,  directs  more  men,  offers 
more  opportunities  than  any- 
other  power  that  man  has  yet 
discovered.  Through  exact 
knowledge  of  Electricity  you 
will  advance  in  salary  and 
position. 

Hawkins  Electrical  Guides 

Will  Show  You  How 

These  books  are  the  standard  works  on  Elec- 
trical Science.  They  are  a  complete  and  up-to-date  course 
in  Electrical  Engineering,  presenting  the  information  in  a 
way  you  can  use  it.  Only  $1.00  per  volume  and  owners  of  the  set 
Bay  there  are  no  better  electrical  books  published  at  any  price. 

Specially  Arranged  for  p™ey 
Home  Study  and  Reference  ggg*  £00°£ nBdea£ 

flexible  black  buckram  with  gold  edges.  Eas.vto  read  and  handle, 
lou  can  carry  each  single  volume  about  with  you  until  you 
have  mastered  the  subject  it  contains.  Written  in  the  form  of 
questions  you  would  ask  and  the  answers  to  them— in  plain 
practical,  everyday  language,  complete,  concise,  authentic  and 
to  the  point.    Over  3L'(J0  pages  and  more  than  4,000  illustrations 


This  interesting  story 
shows  you  the  way  to 
greater  success  in  the 
Electrical  Field. 


' '  For  the  man  not  getting  a 
college  training  and  even  in 
that  case.  I  can  sincerely  say  I 
do  not  believe  there  is  a  better 
set  of  books  in  the  market  to- 
day." Lloyd  D.  Huffman 
Dayton,  O. 

' '  We  consider  Hawkins  Elec- 
trical Guides  the  most  compact 
and  complete  set  of  electrical 
references  in  the  market." 
Noggle  Electric  Works 
Monterey,  Cal. 
"Hawkins  surely  knows  the 
art  of  condensing  informa- 
tion."     Elbridge  F.  Ball 
Buckland,  Conn. 


10  NUMBERS  IN  ALL 


A  Number 
PAYABLE 

00 

A  Month 


X  Shipped  to  You  FREE 

Send  no  monev.    Examine  the  books  first.    Decide  for  vourseif  that  thev  are  the  most 


YOUR 
FREE 

COUPON 


Theo.  Audel  &  Co. 

72  Fifth  Avenue,  N.  Y. 

Please  send  me  for  FREE  exam- 
ination   Hawkins    Electrical  Guides 
(Price    $1.00    each).      Ship    at  once 
prepaid    the    TEN    numbers.      If  sat- 
isfactory I  agree   to  send  you  $1.00  each 
month  until  paid. 

Signature   

Occupation  

Business  Address   

Residence   


Send  no  money.    Examine  the  books  first.    Decide  for  yourself  that  they  are  the  most 
complete  library  of  Electricity  ever  published  and  that  you  cannot  afford  to  be  without 
them.  Every  book  is  complete  in  itself,  but  the  complete  set  is  the  best  bargain.  The 
^^^^  last  volumes  are  just  coming  off  the  press. 

pa  fry    pAYMFNTQ    Accept  this  unusual  offer  now — to-day,  Each 
CHOI     i  MI  Iff  EH  I  w  page — every  ill      -t!on  will  convince  you  of, 
^^^^      the  big  value  we  are  offering.    See  t'ie  E 
books  first,  then  decide.    If  you  desi 
cide  to  keep  them  you  can  make 
settlement  at  only  $1.00  monthly 
until  paid  for 


Theo.  Audel  &  Co. 


72  Fifth  Avenue 
NEW  YORK 


A  FEW  OF  THE  SUBJECTS 

Magnetism— Induction— Experiments  —  Dynamos 
—Electric  Machinery— Motors— Armatures— Arm- 
ature Windings— Installingof  Dynamos— blectn- 
cil  Instrument  Testing  — Practical  Management 
of  Dynamos  and  Motors — Distribution  Systems — 
Wiring— Wiring  Diagrams— Sign  Flashers— Stor- 
age Batteries— Principles  of  Alternating  Currents 
and  Alternators— Alternating  Current  Motors — 
Transformers — Converters — Rectifiers — Alternat- 
ing Current  Systems — Circuit  Breakers — Measur- 
ing Instruments — Switch  Boards — Wiring — Power 
Stations  —  Installing  —  Telephone  —  Telegraph  — 
Wireless — Rells — Lighting— Railways.  Also  many 
Modern  Practical  Applications  of  Electricity  and 
Ready  Reference  Index  of  the  10  numbers. 


Reference 


June  E.  E. 


JULY,  1917 


15  CENTS 


pfeElectrical 


ELECTRICAL    NEWS  ILLUSTRATED 

OLD  U.S. BATTLESHIPS 
TO  THE  FRONT 

SEE  PAGE  I  7  0 


LARGEST  CIRCULATION  OF  ANY  ELECTRICAL  PUBLICATION 


This  is  the  Electrical  Age,  and  this  wonderful  new  profession  is  calling  you.  The 

demand  for  expert  Electricians  is  greater  every  year  and  the  salaries  higher.  Elec- 
tricity is  truly  the  greatest  motive  power  in  the  world,  to-day,  and  now  is  the  time  to 
enter  this  profession. 


YOU  CAN  DO  THIS 


AFTER  HOME  STUDY 


362?  TO  $10022  A  WEEK 


You  can  earn  $36  to  $100  a  week  and  more  as  an  Expert  Electrician.  If  you  have  a 
common  school  education  I  can  train  you  in  a  few  months  at  home.  Big  lighting  and 
power  companies,  municipalities,  and  manufacturers  are  always  seeking  trained  men  to 
handle  their  Electrical  problems. 

I  Guarantee  Satisfaction 

Every  student  receives  our  Sealed  Guarantee  Bond,  which  guarantees  to  return  every  penny  of  his 
money  if  he  is  not  entirely  satisfied.  No  other  school  has  made  this  wonderful  offer,  but  I  know  the 
success  I  have  brought  to  hundreds  of  my  students,  and  I  know  what  I  can  do  for  any  ambitious  young 
man  who  will  give  me  a  little  of  his  spare  time  each  day 

FREE  ELECTRICAL  OUTFIT 


MAIL  THIS  COUPON 


Dept.  37, 

CHIEF  ENGINEER,  Chicago  Engineering  Works, 
439  Cass  St.,  Chicago,  Illinois. 

Without  obligation  on  my  part  kindly  send  at  once,  fully  prepaid, 
particulars  of  your  complete  Practical  Home  Study  Course  in  Elec- 
tricity. 


Name 


Addr 


Town    State. 


For  the  next  30  days  I  am  giving  each  student  an  Outfit  of 
Electrical  Testing  Instruments,  Tools,  Electrical  materials,  and 
Motor  absolutely  Free.  My  instruction  is  by  practical  methods  and 
this  outfit  is  used  in  working  out  the  lessons.  Practical  training 
with  the  theory  makes  perfect.  I  am  Chief  Engineer  of  the  Chicago 
Engineering  Works,  and  I  can  give  you  the  training  that  will  land 
the  big  jobs  and  hold  them. 

If  you  are  in  real  earnest  I  want  to  send  you  my  new  Book — 
"How  to  Become  an  Electrical  Expert."  It's  free.  No  matter 
how  many  other  schools  you  write  to  I  want  you  to  have  my  book 
— It's  different  because  it's  practical — Write  today. 

CHIEF  ENGINEER  COOKE 

CHICAGO  ENGINEERING  WORKS 

Dept.  37      ::       439  CASS  STREET,  CHICAGO,  ILL. 


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ly,  1917 


THE  ELECTRICAL  EXPERIMENTER 


161 


Read  iHitlitmaikdhlf  Of  fei  1 


This  masterpiece  contains  160  pages,  400  illustrations.  Size 
of  book  5"  x  9".    Printed  on  extra  thin  paper,  so  book  can 
be  slipped  in  pocket.    Handsome  stiff  cloth  cover. 
Price  $1.00  if  bought  alone.  FREE  with  a  year's  subscription. 


The  most  comprehensive  Wireless  Course  ever  printed.  Con- 
tains 160  pages,  350  illustrations.  Size  of  book  6J^//  x  9.'1 
Very  fine  flexible  linen  cover. 

Price  $1.00  if  bought  alone.  FREE  with  a  year's  subscription. 


^Electrical  m 
S  Experimenter  Sj 


This  is  a  very  limited  offer.  It  may  be  withdrawn  at  any  time,  due  to  the 
tremendous  cost  of  paper,  which  IS  JUST  DOUBLE  WHAT  IT  WAS  ONE 
YEAR  AGO.  We  only  have  about  2000  each  of  these  fine  books  on  hand  ;  after 
they  are  gone  we  cannot  reprint  the  books  until  conditions  become  normal  again 
THIS  MAY  BE  TWO  YEARS  OR  MORE.  Now  is  your  chance. 
The  publishers  of  this  journal  have  earned  an  enviable  reputation,  of  giving 
more  than  100  cents'  worth  for  each  dollar  spent  with  them.  Profit  by  this  liberal 
opportunity  NOW;  it  may  never  be  made  again. 

HERE'S  THE  OFFER 


Subscribe  to  THE  ELECTRICAL  EXPERIMENTER  for  one  year,  at 
the  regular  subscription  price  of  $1.50  per  year  (Canada  and  for- 
eign $2.00)  and  we  will  send  you  FREE  POSTPAID,  either  one  of 
the  above  books.    If  you  subscribe  for  two  years,  BOTH  BOOKS         ,^^rQ>  / 

WILL  BE  GIVEN  FREE,  POSTPAID.  ^^C-' 


V 


12  copies  of  THE  ELECTRICAL  EXPERI- 
MENTER make  a  book  9"  x  12"  and  4"  thick. 
This  book  will  weigh  7  lbs.  It  is  the  greatest 
Electrical  and  Wireless  reference  d*1  CA 
work  in  the  world.    And  all  for  <4>J-««'V 


If  you  are  a  subscriber  at  present,  take  advantage  of  this 
wonderful  opportunity  anyway.  If  you  do,  we  will  extend 
your  present  subscription  for  one  year. 

This  Offer  Limited.    Act  Now 

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Gentlemen: 

Please  enter 
my  subscription 
to   THE  ELEC- 
TRICAL EXPERI- 
M  ENTER  for  the 

pr^_  v,         termor  year  

Q,'  for  which  I  enclose  heie- 
/        with  $  

You  will  also  send  me  at  once 
FREE  prepaid  your  book..  . 


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162 


THE  ELECTRICAL  EXPERIMENTER 


July,  1917 


MrTTmes  Gil  fbr 

More  Electricians 


Without  the  help  of  trained  electricians  on  our  battleships,  in  the  army  and  in  the  thousands  of  man- 
ufacturing and  transportation  industries  behind  the  fighting  line  the  United  States  cannot  hope  to  win  the 
war.  More  young  men  must  be  found  and  trained  AT  ONCE  for  the  thousands  of  new  positions  in  the 
electrical  field.  Send  the  coupon  below  for  full  particulars.  Hundreds  and  thousands  of  Expert  Electri- 
cians are  giving  up  their  positions  to  become  soldiers.  Their  places  must  be  filled — quickly.  The  work 
they  have  been  doing  cannot  wait  for  their  return.    If  you  cannot  fight  at  the  front,  it  is  your  duty  to  prepare 

yourself  NOW  to  help  at  home — not  only  with  your  hands  but  with  a  trained 
mind  and  a  trained  skill.  The  President  says  our  production  and  efficiency  must 
be  doubled.  He  means  YOU — your  efficiency.  Don't  shirk  your  duty.  Do 
...  'NOW,  for  your  country's  sake,  what  you  might  not  do  for  your  own  sake. 
Fit  yourself  for  important,  vitally  essential  work  as  an  Expert  Electrician. 

Learn  NOW — at  home — by 
Wonderful  NEW  SYSTEM 


ALBERT  WOOD  WICKS,   B.S.,  E 
President  and  Director 

Wicks  Electrical  Institute 


You  will  be  amazed  to  find  how  easily  and  quickly  you  can  become  an 
Expert  Electrician  under  my  training.  My  remarkable  new  method  of  teaching 
electricity  at  home  is  entirely  different  from  any  other — astonishingly  simple. 
A  few  minutes'  study  each  day  in  your  spare  time  is  all  that  is  required  to  master 
this  big,  money-making  business.  No  previous  education  required.  I  positively 
guarantee  your  success  no  matter  who  you  are  or  where  you  live.  Expert 
Electricians  are  needed  everywhere  in  these  war  times  at  salaries  of  $2,400 
to  $4,000  a  year. 


Lessons 

WEE 


The  most  sensational  offer  ever  made.  I 
make  this  extraordinary  offer  as  a  patriotic 
duty,  because  I  owe  it  to  my  country  to  do 
everything  I  can  to  help  furnish  trained 
electricians  to  meet  the  great  demand. 
TWENTY  COMPLETE  LESSONS  AB- 
SOLUTELY FREE.  Send  the  coupon  be- 
low. Judge  for  yourself  whether  you  can 
learn  under  my  expert  instruction.  But  re- 
member, I  can  accept  only  a  limited  number 
of  students  on  this  Free  offer.  Write  at 
once.  Every  one  of  these  Special  students 
will  receive  my  personal,  individual  instruction,  and  I  will  help  them  to 
*\   finish  the  entire  course  in  a  few  short  months. 


A.  W.  WICKS,  B.S.,  E.E.,  Director  * 
Wicks  Electrical  Institute  ^ 
81  W.  Randolph  Street  - 

CHICAGO,  ILL.  \ 

Dept.  537  ^ 

Without  any  obligation  on  my  part,  please  send  me  full 
particulars  of  your  20  Free  Lessons  Offer,  and  all  other  in- 
formation about  your  wonderful  new  system  for  teaching 
Electricity  at  home. 


Name . 


RUSH  THIS  COUPON 

You  have  no  time  to  lose.    I  may  have  to  withdraw  this  offer  any  day,  as  soon  as  I  have 
accepted  as  many  students  as  I  can  personally  teach.    Act  before  it  is  too  late.    Get  ready 
at  the  earliest  possible  moment  to  prove  your  patriotism  by  stepping  into  an  Expert  Elec- 
trician's job.    Help  your  country  not  only  with  your  hands,  but  with  your  brain.    Let  me 
train  you.    If  you  want  to  receive  20  complete  Lessons  of  my  wonderful  new  course 
i       entirely  free,  tear  off  the  coupon  and  mail  it  today — this  minute.    Or  send  a  postal. 
^      This  Special  Announcement  may  not  appear  again. 

\      ALBERT  WOOD  WICKS,    President  and  Director 

\    Wicks  Electrical  Institute 

\  Dept  537     81  W.  Randolph  Street  CHICAGO 


Address. 


You  benefit  by  mentioning  "The  Electrical  ^Experimenter"  when  writing  to  advertisers. 


Electrical 


ram 


233  FULTON  STREET,  NEW  YORK 


Publisht  by  Experimenter  Publishing  Company,  Inc.  (H.  Gernsback,  President;  S.  Gernsback,  Treasurer;)  233  Fulton  Street,  New  York 


Vol.  V    Whole  No.  51 


CONTENTS  FOR  JULY,  1917 


No.  3 


OLD  U.  S.  BATTLE-SHIPS  TO  THE  FRONT.   Front  Cover 

From  a  painting  by  George  Wall 
LOCATING  AND  DESTROYING  SUBMARINES  WITH  A  RED 

LIGHT  RAY    165 

•COLD  LIGHT    166 

HOW  THE  SUBMARINE  CAN  HIT  A  SHIP  IT  NEVER  SEES... 

By  H.  Winfield  Secor  167 

DOES  RADIANT  LIGHT  POSSESS  WEIGHT?. By  A.  R.  McPherson  168 

WAR  AND  RADIO  IN  THE  MOVIES   169 

U.  S.  BATTLE-SHIPS  TO  RUN  ON  LAND  By  H.  Gernsback  170 

THE    MARVELS    OF  RADIO-ACTIVITY  

By   Terome  S.   Marcus — Part  I  171 

BACK  TO  THE  DAYS  OF  VOLTA   172 

SOME  ODD  X-RAYS    173 

LIGHTNING— HOW  TO  PROTECT  YOURSELF  FROM  IT  

By  W.   G.  Whitman  174 

THE  SCIENCE  OF  SOUND   176 

SPEEDING  UP  VOTE  OF  CONGRESS  BY  ELECTRICITY   179 

"HAM"  JONES— SCIENTIST  By  Harlan  A.  Eveleth  180 

20.000  VOLTS  DIRECT  CURRENT   182 


TESTING  RADIO  UNITS  WITH   DUMMY  ANTENNA  

By  Frank  C.  Perkins 

HOW  RADIO  BROUGHT  THE  NEWS  TO  THE  FARM  

The  story  of  Archie  Banks 

WIRELESS  ON  THE  AMERICAN  SUBMARINE  CHASERS  

By   Samuel  Cohen 

AN  IMPROVED  BURGLAR  ALARM  UTILIZING  THE  "STICK 

RFLAY"  By  Albert  H.  Beiler 

CONSTRUCTING  A  54-TON  LIFTING  MAGNET  By  J.  Lwak 

MORE  ABOUT  THE  "PERPETUAL"  ELECTRIC  CLOCK  

By  Howard  W.  Lewis 

HOW-TO-MAKE-IT  DEPARTMENT    199 

AMATEUR  AND  EXPERIMENTAL  RADIO  RESEARCH— PART  I. 

By  Raymond  Francis  Yates  201 
EXPERIMENTAL  CHEMISTRY— LESSON  14... Bv  A.  W.  Wilsdon  203 
WRINKLES,  RECIPES  AND  FORMULAS .. Edited"  by  S.  Gernsback  204 

LATEST   PATENTS   DIGEST   208 

PHONEY  PATENT  CONTEST    209 

QUESTION  BOX    210 


186 


16 


190 


194 
195 


196 


War  and  the  Invento 


N  this  great  crisis,  a  word  to  our  patriotic 
inventors  will  not  be  amiss.  As  I  have 
pointed  out  before,  the  average  inventor  is 
a  poor  business  man  and  a  worse  salesman. 
No  matter  how  clever  or  how  ingenious 
he  is,  he  will  insist  upon  presenting  his 
story  in  the  worst  possible  manner.  As  a 
rule  he  has  labored  for  nights  upon  nights  in  solving  an 
important  problem  ;  every  phase  of  the  invention  is  so 
clear  and  lucid  to  him  that  he  becomes  irritable  and  angry 
if  those  about  him  do  not  at  once  grasp  all  the  details.  Or 
else,  in  his  enthusiasm,  he  will  sit  down  and  taking  a 
piece  of  brown  wrapping  paper  and  a  pencil,  he  will 
forthwith  begin  to  write  out  a  few  often  unintelligible 
phrases,  garnished  with  incomprehensible  sketches, 
which  are  supposed  to  clearly  explain  his  invention.  He 
closes  the  missile  by  offering  his  device  "free  and  gratis'' 
to  the  Government,  puts  it  in  an  envelope  addrest  to  the 
Secretary  of  the  Navy,  and  then  mails  the  letter,  think- 
ing that  he  has  done  a  great  patriotic  act.  Then  if  a 
long  ominous  silence  follows,  the  inventor  as  a  rule  be- 
comes embittered  and  hostile  to  the  Government. 

Now,  this  is  no  exaggeration.  As  Editor  of  "Patent 
Advice"  I  receive  from  twenty  to  thirty  letters  a  day,  to 
be  transmitted  to  the  Government,  if  in  my  estimation 
the  device  is  practical.  And  not  two  of  these  ideas  are 
submitted  in  a  presentable  or  even  an  intelligent  manner. 
Penciled  letters  prevail  and  often  the  sender  forgets  to 
sign  his  name.  And  in  Washington  the  War  and  Navy 
Departments  are  deluged  daily  with  just  this  sort  of 
mail,  ninety-nine  percent  of  which  is  discarded.  And  it 
probably  happens  once  in  a  while  too,  that  the  Govern- 
ment loses  a  really  good  idea  simply  because  the  one 
submitted  was  unintelligible  and  in  consequence  found 
its  grave  in  a  waste  basket. 

Now  the  man  at  his  desk  in  Washington  is  human — 
and  consequently  weak.  Try  as  he  may,  he  will  pay  more 
attention  to  a  neatly  typed  letter,  than  to  a  scrawly  pen- 
ciled note.  A  correctly  drawn  sketch  will  at  least  arouse 
a  passing  interest,  whereas  a  misshapen  free-hand  pen- 
cil design,  will  rarely  fetch  a  spark  of  enthusiasm. 

The  inventor  would  not  dream  of  running  to  the  War 
Department  in  armsleeves,  unkempt,  unshaven  and  in  a 
soiled  and  torn  shirt.  But  he  insists  on  sending  the 
child  of  his  brain  just  that  way. 

If  you  have  an  idea  that  you  think  is  worthy,  this  is 


the  way — the  only  way — to~TtT^Safcl^#Tf?ember  first, 
that  the  Government  receives  daily  thousands  of  useless 
letters  from  inventors — yours  may  be  useless,  no  matter 
what  YOU  think.  Remember  too  that  there  is  no  greater 
intoxicant  than  a  newly  born  invention  ;  under  its  in- 
fluence you  are  in  no  condition  to  think  straight,  least 
of  all  sending  your  invention  to  Washington.  I  have 
been  intoxicated  myself  dozens  of  times  in  precisely 
this  manner  and  I  know  whereof  I  speak. 

First  you  should  take  your  plan  to  a  trusted  friend 
who  is  versed  in  mechanics  or  electricity.  Invite  crit- 
icism. Obtain  expert  opinion.  Remember  you  don't 
know  it  all — no  one  does.  Edison  says  he  is  just  begin- 
ning to  know  a  few  Nothings. 

If  the  expert  advice  convinces  you,  that  you  really 
have  a  worthy  device,  then  and  only  then  begin  to  think 
about  Washington.  Have  someone  tvpewrite  vour  idea 
in  a  neat  and  clear  manner  AND  MAKE  IT  "SHORT. 
Long  explanations  hurt  your  cause.  Use  the  telegraphic 
style,  just  as  if  you  had  to  pay  for  each  word  and  don't 
attempt  to  make  your  own  drawing,  unless  you  are 
thoroly  'familiar  with  drafting  instruments.  Find  a 
draftsman  who  will  make  a  creditable  drawing  in  China 
ink  upon  a  bristol  board.  Then  sign  your  name  and 
address  to  BOTH  description  and  drawing,  and  mail  the 
two  FLAT.  Don't  roll  either  manuscript  or  drawing. 
But  use  a  piece  of  heavy  stiff  cardboard  to  keep  the  con- 
tents of  your  letter  from  being  folded  in  the  mails.  If 
you  do  this  I  promise  you  a  warm  letter  of  thanks  from 
the  official  who  reads  your  invention. 

Moreover,  don't  send  your  letter  to  your  Congressman 
or  to  your  Senator,  as  many  misguided  inventors  are 
wont  to  do.  At  best  it  only  delays  it.  Instead,  address 
it  to  either  the  Secretary  of  War,  or  to  the  Secretary 
of  the  Navy,  all  depending  upon  what  subject  your  in- 
vention treats.  Last  but  not  least  don't  worry  our  offi- 
cials with  torpedo  or  submarine  catchers  which  depend 
upon  magnets.  The  majority  of  ideas  submitted  are 
based  upon  this  popular  delusion.  Here  are  facts:  If 
you  had  an  electromagnet  that  would  attract  one  million 
pounds  (no  such  animal  was  ever  built!)  a  steel  torpedo 
rushing  by  it  at  a  distance  of  20  feet  would  not  be  devi- 
ated one  inch  from  its  course.  For  the  largest  electro- 
magnet exerts  practically  no  tangible  force  a  few  feet 
away  from  its  poles. 

H.  GERNSBACK. 


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THE  ELECTRICAL 
EXPERIMENTER 


H.  GERN5B&CK  editpr 
H.  W.  5ECPR  /i55DcmTE  editpr 


Vol.  V.    Whole  No.  51 


July,  1917 


Number  3 


Locating  and  Destroying  Submarines  with  Red  Light 


ANEW   method  due  to   Yankee  in- 
genuity and  intended  for  locating 
submerged  sub-sea  boats  at  a  con- 
siderable range  has  recently  been 
worked  out.    It  has  been  described 
by  a  retired  naval  officer  and  appears  to 
have  made  a  favorable  impression  on  the 
navy's  experts. 

If  once  it  becomes  possible  to  locate 
the   presence   of  an   enemy  submarine, 


the  high  seas  with  safety,  so  far  as  sub- 
marine attacks  are  concerned. 

As  may  be  imagined,  the  experiment- 
ers in  this  field  are  not  willing  to  make 
public  the  actual  experiments,  details 
and  results  accomplished,  but  the  fol- 
lowing outline  of  the  method  now  under 
consideration  will  be  of  great  interest 
to  the  public. 

Inasmuch  as  the  great  advantage  of 


or  taste  a  submarine  over  a  mile  distant, 
so  we  are  left  only  two  of  the  senses 
remaining — the  sense  of  the  eye  and  that 
of  the  ear. 

The  microphone  enables  us  to  hear 
more  or  less  distinctly  the  engines  of 
the  submarine  when  they  are  working 
at  more  than  slow  speed,  but  this  is  not 
sufficient,  as  a  submarine  lying  in  wait 
to  torpedo  a  vessel  needs  only  to  turn 


Why  Not  Locate  the  Submerged,  Yet  Always  Dangerous,  Enemy  Submarines  by  Continually  Flashing  a  Powerful  Red  Searchlight  Beam 
Back  and  Forth  Thru  and  Under  the  Water,  Asks  a  Yankee  Genius.  Once  a  "Bulge"  Is  Spotted  (Day  or  Night)  in  the  Light  Beam,  the 
Observer  on  the  Mast  Signals  That  Fact  to  the  Gun  Crews.    Consequence — as  Soon  as  the  Periscope  Appears  the  Already  Trained  Guns 

Open  Fire.     The  Spotting  Range  Is  Over  Two  Miles,  Day  or  Night. 


then  the  greatest  worry  of  cargo  steam- 
ship captains  will  be  over,  for  when  the 
"sub's"  location  is  spotted  then  the  ves- 
sel's guns  will  be  trained  on  the  spot. 
As  soon  as  the  under-water  boat  comes 
to  the  surface  to  take  her  sightings  she 
will  be  met  with  a  hail  of  shot  and  shell. 

The  new  method,  holding  great  prom- 
ise for  the  destruction  of  the  submarine 
and  its  entire  elimination  as  an  efficient 
weapon  of  warfare  is  now  being  per- 
fected, and  it  is  probable  that  within 
a  very  few  weeks  vessels  may  navigate 


the  submarine  over  surface  vessels  is 
the  fact  that  it  is  hidden  from  view, 
if  by  some  means  the  exact  location 
is  made  known  to  a  vessel  before  she 
approaches  within  the  danger  range  (2,- 
000  to  2,500  yards)  of  the  submarine, 
the  menaced  vessel  can  invariably  es- 
cape. 

In  seeking  methods  to  be  employed 
for  certain  purposes,  inventors  and  ex- 
perimenters frequently  turn  to  the  five 
senses  when  beginning  the  solution  of 
a  baffling  problem.    We  cannot  feel,  smell 


her  engines  over  very  slowly  to  main- 
tain her  depth  below  the  surface. 

A  submarine  vibrator  operated  by 
electricity  has  produced  an  echo  from 
an  iceberg  two  miles  distant,  but  it  is 
doubtful  if  the  system  can  be  improved 
to  efficiency  in  the  case  of  the  submarine. 
Now  let  us  consider  our  remaining  sense: 
sight. 

When  our  ship  approaches  the  danger 
zone  of  the  submarine  the  latter  is  main- 
taining  a   heading   which    is   nearly  at 
(Continued  an  page  215) 


166 


THE  ELECTRICAL  EXPERIMENTER 


July,  1917 


WE  are  accustomed  to  seeing  the 
electric  or  other  source  of  light 
with  unfeeling  senses,  i.  e.,  with- 
out stopping  to  realize  for  one 
moment  that — while  it  is  undeni- 
ably true  that  the  modern  electric  light  is 
a  masterpiece  of  scientific  attainment, 
thanks  to  Edison  and  other  investigators — 
we  are  actually  paying  many  times  what 
we  should  expend  for  this  human  com- 
fort. Think  for  one  moment  that  only 
3  per  cent  of  the  electrical  energy  put  into 
a  modern  gas-filled,  tungsten  filament,  in- 
candescent electric  lamp  is  realized  as  use- 
ful light;  the  balance  of  the  energy  is  paid 
for  and  uselessly  dissipated  in  the  form  of 
heat  and  other  radiation. 

The  fire-fly  is  one  of  the  greatest  and 
absorbing  wonders  of  all  Nature.  Why? 
— because  he  knows  how  to  produce  prac- 
tically a  cold  light.  The  illumination  engi- 
neers of  today  are  studying  the  problem 
with  all  the  resources  at  their  command. 
There  ought  to  be — there  must  be  a  way  in 
which  to  convert  all  or  nearly  all  of  the 
electrical  energy  into  useful  light.  The 
electric  motor  converts  electrical  energy 
into  mechanical  energy  with  an  over-all 
efficiency  of  90  to  98  per  cent.  Suppose 
we  had  perfected  an  electric  motor  with  an 
efficiency  of  but  3  per  cent;  how  many 
motors  do  you  think  there  would  be  in 
use?    Yet  we  are  content,  at  least 


Cold  Light 

substitution,  the  intermittent  flashes  pro- 
ducing the  effect  of  a  steady  light.  Each 
lamp  is  in  consequence  lighted  for  so  short 
a  time  period  that  the  infinitesimal  amount 
of  heat  developed  is  quickly  dissipated. 
The  cooling  interval  is  about  twice  that  of 
the  light  interval.  The  lamps,  moreover, 
can  in  this  way  be  operated  on  3  to  4  times 
the  normal  voltage,  vastly  increasing  the 
efficiency  and  illumination  of  each  filament 
thereby.    It  is  said  that  Dussaud  has  suc- 


luminous  rays  are  concentrated  in  a  very 
small  point  or  space.  The  tungsten  lamps 
employed  are  of  Dussaud's  own  design. 
Some  of  them  are  only  0.8  to  1.6  inches 
in  radius.  Groups  of  three  are  used  in 
some  models.  They  are  successively  flashed 
in  the  focus  of  a  condensing  lens,  without 
breaking  down  the  filament  or  blackening 
the  bulb.  Indeed,  it  is  said  that  the  re- 
sults produced  are  identical  with  those 
obtained  with  an  electric  arc  ten  times  more 
intense. 

For  motion  picture  projection  machines 
the  new  cold  light  possesses  wonderful 
merits,  enabling  the  operator  to  run  the 
film  off  as  slowly  as  desired,  and  even  to 
stop  the  film  for  examination  when  neces- 
sary. Dussaud,  scientist,  has  projected  mo- 
tion pictures  on  a  screen  15  feet  square  with 
an  electrical  energy  consumption  of  150 
watts,  compared  to  the  5  to  10  kilowatt 
(5,000  to  10,000  watts)  arcs  now  used.  And. 
the  cold  light  machine,  complete  with  gen- 
erator, could  be  carried  easily  in  the  hand. 
Due  to  this  rapid  dissipation  of  heat,  it 
becomes  possible  to  employ  celluloid  instead 
of  glass  plates  for  ordinary  lantern  slides 
with  no  danger  of  igniting  the  celluloid  or 
of  causing  it  to  shrivel  up.  Dussaud  has 
prophesied  that  with  his  cold  light  it  will 
be  possible  to  use  celluloid  films  ^4  of  an 
inch  by  1  inch  in  size  instead  of  glass 
plates  3K  by  4  inches.    The  celluloid  can 


Above  —  Complete     Dussaud  Experimental 
"Cold    Light"  '  with   Generator  and  Current 
Measuring  Meters. 

we  know  more  about  the  subject,  to  use 
electric  lights  with  this  almost  unbelievably 
low  conversion  efficiency. 

One  of  the  nearest  approaches  to  man- 
made  cold  light  is  that  of  Professor  C.  F. 
Dussaud,  French  scientist  and  investigator. 
The  accompanying  views  show  some  of  the 
successful  apparatus  devised  by  him,  also 
their  applications.  Dussaud  has  evolved  a 
very  ingenious  arrangement,  which,  altho 
not  giving  a  true  heatlcss  light,  yet  pro- 
duces light  with  a  negligible  quantity  of 
heat. 

The  elementary  principle  upon  which  this 
so-called  cold  light  is  based  is  that  of  im- 
pressing at  sufficiently  close  and  intermit- 
tent intervals  an  excess  voltage  of  several 
times  the  normal  value-  to  each  lamp.  To 
accomplish  this  a  number  of  incandescent 
lamps  are  arranged  in  a  circle  on  a 
rotatable  disc  as  shown  herewith.  This  disc 
may  be  rotated  by  hand  or  by  an  electric 
motor.  The  lamps  have  metal  bases  and 
a  metal  brush  contact  is  caused  to  press 
against  one  base  at  a  time.  All  the  lamp 
bases  have  one  of  their  poles  connected 
to  a  common  return  contact,  made  in  the 
form  of  a  ring,  at  the  back  of  the  disc, 
against  which  a  second  metallic  brush 
makes  contact.  As  seen  it  now  becomes 
possible  to  rapidly  switch  one  lamp  after 
the  other  into  circuit,  consecutively.  The 
persistence  of  vision  of  the  retina  of  the 
human  eye  defies  the  detection  of  the  lamp 


Top  Center  View — A  "Cold  Light"  Projector 
of  the  Dussaud  Type  Intended  for  Use  by 
Firemen  and  for  Military  Purpose's.  Center 
— Rear  View  of  "Cold  Light"  Machine. 
Lower  Center — A  Three-Lamp  Projecting 
"Cold  Light"  Apparatus. 

ceeded  in  obtaining  250  to  800  CP.  of  cold 
light  for  several  hours  from  a  bank  of  16 
lamps  rated  normally  at  only  25  to  80  CP. 
with  an  energy  in-put  of  50  to  160  watts. 

Professor  Dussaud  employs  an  optical 
system  with  his  lamps,  in  other  words, 
either  lenses  or  mirrors.  The  result  is 
that  while  the  heat  effect  of  the  electric 
current  is  dissipated  over  a  great  area,  the 


Above — The    Microscopic    Projection    of  a 
"Cold  Light"  Beam  as  Devised  by  Prof.  Dus- 
saud of  France. 

be  cut  into  long  strips,  perforated  along 
the  edges  so  that  it  can  be  printed  mechan- 
ically, as  in  making  moving  picture  posi- 
tives. Indeed,  he  claims  that  a  single 
operator  can  make  twenty-five  thousand 
celluloid  prints  a  day.  These  tiny  photo- 
graphs can  be  made  by  any  amateur  at  a 
cost  of  not  more  than  a  cent,  and  can  be 
projected  on  the  screen  by  means  of  small, 
low-priced  projectors. 

By  utilizing  the  marvelous  cold  light 
auto-chrome  plates  can  be  projected,  which 
otherwise  suffer  when  exposed  to  the  in- 
tense heat  of  the  electric  arc.  Powerful 
lights  can  be  concentrated  upon  parts  of  the 
human  body  without  danger  of  scorching 
them,  with  the  result  that  foreign  bodies 
can  be  located  very  readily  in  the  muscles. 

The  cold  light  lends  itself  admirably  to 
the  photographing  of  interiors.  The  incon- 
veniences attending  the  use  of  ordinary 
magnesium  flash  powder  are  well  known. 
Powerful  cold  lights  render  it  possible  to 
make  very  brief  exposures  without  filling 
the  atmosphere  of  the  room  with  smoke 
and  fumes. 

With  a  small  electric  battery  and  a  sim- 
ple lens,  a  beacon  light  of  long  range  can 
be  cheaply  produced.  Such  an  apparatus 
will  be  found  serviceable  on  small  sailing 
boats  as  well  as  by  soldiers.  It  is  easy 
enough  with  such  a  device  to  telegraph 
optically  for  great  distances.  One  of  the 
views  shows  the  microscopic  projection  of 
cold  light. 


July,  1917 


THE  ELECTRICAL  EXPERIMENTER 


167 


How  the  Submarine  Can  Hit  a  Ship  It  Never  Sees 


THE  German  submarine  has  finally 
become  a  most  menacing  factor  in 
the  great  world-war  and  now  pre- 
sents a  first-class  problem  to  all 
the  would-be  and  master  inventors 
— electrical,  mechanical — and  fourth-dimen- 
sion. Remember  reading  now  and  then  in 
the  daily  papers  bow  "another"  merchant 
vessel  was  torpedoed  and  the  officers  saw 
no  submarine?  Sank  in  10  minutes  and 
crew  left  in  the  water  to  float  ashore  or 
possibly  to  be  picked  up  by  a  patrol  boat. 
Yes,  there  have  been  a  lot  of  such  cases 


By  H.  WINFIELD  SECOR 

requires  to  sound  the  death  knell  of  the 
proud  merchantman. 

And  sound  it  he  does,  for  as  soon  as 
he  has  the  necessary  data  on  your  status 
and  position,  he  at  once  transmits  it  thru 
the  water  by  powerful  sound  waves  to 
one  or  more  submerged  sub-sea  fighters 
lying  in  the  path  of  the  on-coming  steamer. 
Knowing  the  location,  direction  and  speed 
of  the  unsuspecting  commerce  boat,  the 
hidden  submarine  (or  submarines)  can  dis- 
charge a  torpedo  sufficiently  accurate  to 
spell  the  finish  of  the  "barred  zone"  prey. 


at  the  receiving  station,  and  which  is  set 
into  vibration  by  the  sound  waves  or  vibra- 
tions in  the  water.  Prof.  Fessenden  has 
succeeded  in  telephoning  several  miles  by 
means  of  such  sound  vibrations  propagated 
thru  water.  Thus  we  see  how  it  is  not 
only  feasible,  but  entirely  possible  for  a 
submarine  to  torpedo  a  ship  without  ever 
having  seen  it. 

(The  above-mentioned  sound  wave  sub- 
sea  telegraph  apparatus  was  fully  described, 
with  photographs,  in  our  August,  1915, 
and  February,  1916,  issues.) 


The  Latest  Reports  Regarding  Submarine  Activities  Frequently  State  that  the  Ship  Was  Torpedoed  by  an  "Unseen"  Sub-sea  War-vessel. 
This  Can  Easily  Be  True  for,  by  Utilizing  Telegraphic  Sound-waves  Propagated  Thru  Water  (Fessenden  System),  a  Relatively  Distant 
"Range-finding"  Submarine  Can  Signal  Her  Hidden  Allies  as  to  the  Position  and  Course  of  the  Enemy.     Thus  the  Submarine  That  Fires 

the   Fatal   Torpedo    Need    Never  Show   Its  Periscope. 


as  this  and  even  more  mysterious  ones. 
For  instance  there  is  the  case  where  the 
ship's  lookout  remembers  having  seen  an 
enemy  submarine  several  miles  off — much 
too  far  to  be  within  torpedo  range.  More- 
over, nothing  more  had  been  seen  of  the 
enemy  after  the  first  sighting,  but  sud- 
denly— a  terrible  explosion  fairly  lifted  the 
boat  out  of  the  sea — torpedoed?  Sure  as 
guns  ?  But  how  ?  asks  everyone,  from  Cap- 
tain down ;  yes,  how  ?  and  in  broad  day- 
light ! 

That's  the  question — and  it  now  seems 
that  there  is  an  answer.  Possibly  the 
reader  has  guest  it  by  looking  at  tbe  ac- 
companying illustration.  At  any  rate  here's 
a  new  aspect,  and  what  is  more,  a  thoroly 
practical  one  of  the  science  of  submarin- 
ing. Let  us  admit  that  the  officers  on 
the  merchant  ship  spot  a  periscope  sev- 
eral miles  away,  or  even  a  mile  and  a  half 
away.  That's  an  almost  impossible  target 
to  hit  with  any  kind  of  gun  and  the 
chances  are  the  submarine  couldn't  shoot 
a  torpedo  once  in  ten  times  to  hit  the  mer- 
chantman at  such  a  range. 

However,  the  German  sub-sea  boat  com- 
mander doesn't  have  to  worry  about  sink- 
ing the  freighter  with  a  torpedo  from  his 
submarine.  Not  at  all.  Give  him  a  few 
minutes  to  draw  a  bead  on  your  position 
and  your  speed,  as  well  as  the  course,  with 
his  periscope  and  range-finding  instru- 
ments.    That   is   all   the  information  he 


The  illustration  shows  this  remarkable 
maneuver  in  a  grafic  manner.  The  mer- 
chantman may  even  fire  on  the  periscope 
of  the  distant  submarine,  but  as  aforemen- 
tioned the  chances  of  hitting  it  at  a  range 
of  V/2  to  2  miles  are  very  slim.  Besides, 
the  spotting  submarine  may  have  been 
watching  the  steamer  for  some  minutes 
before  the  latter's  look-out  spies  the  cun- 
ningly disguised  and  mottled  periscope. 
At  the  first  shot  from  the  steamship's  gun 
crew  the  submarine  may  disappear.  Con- 
sider that  the  U-boat  commander  has  the 
range  of  the  enemy ;  he  at  once  dispatches 
the  .data  by  sub-sea  telegraphy  or  tele- 
phony, so  that  other  U-boats  lying  sub- 
merged or  awash  at  the  surface,  will  re- 
ceive the  information  on  their  sound  wave 
apparatus. 

All  this  may  sound  somewhat  mytho- 
logical— but  it  is  not.  Our  own  sub-sea 
fighters  and  war  vessels  are  all  equipt 
with  similar  instruments.  They  are  based 
upon  the  researches  of  Prof.  Reginald 
A.  Fessenden,  the  well-known  American 
inventor  and  scientist,  and  involve  the  prin- 
ciple that  water  will  transmit  sound  waves 
remarkably  well.  To  set  up  such  sound 
waves  of  sufficient  power  to  carry  sev- 
eral miles  (in  tests,  this  method  of  com- 
munication has  worked  up  to  20  miles)  a 
special  heavy  diafram  is  employed,  which 
is  caused  to  vibrate  rapidly  by  electro- 
magnetic means.    A  similar  diafram  is  used 


ELECTRICAL  TREATMENT  OF 
BRITISH  WOUNDED. 

In  a  recent  number  of  the  "Lancet,"  Dr. 
W.  J.  Turrell  describes  various  applica- 
tions of  electro-therapy  at  the  Radcliffe 
Infirmary,  Oxford,  England.  One  inter- 
esting point  is  the  treatment  of  unclean 
wounds  by  ionization',  produced  either  by 
the  application  of  salt  solutions  traversed 
by  an  electric  current,  or  by  means  of  ultra- 
violet rays.  As  is  well  known,  electric 
currents  are  now  much  used  in  treating 
certain  varieties  of  rheumatism. 

Of  considerable  importance  is  the  appli- 
cation of  mild  electric  "shock"  to  stimulate 
the  voluntary  movements ;  the  treatment  is 
specially  efficacious  in  those  cases  of  nerve 
shock  where  the  patient  is  under  the  de- 
lusion that  he  has  lost  the  power  of  his 
limbs. 

However,  the  application  of  electric 
methods  to  cases  of  "shell-shock"  calls  for 
discretion.  In  some  such  cases  the  pa- 
tient is  not  at  all  benefited  and,  indeed, 
exhibits  "electrophobia." 

Currents  are  also  a  valuable  means  of 
testing  the  action  of  various  muscles  and 
the  powers  of  sensation,  and  in  producing 
movements  which  break  down  internal  ad- 
hesions or  the  binding  of  scar-tissue.  The 
static  machine  is  considered  specially  use- 
ful in  this  direction. 


68 


THE   ELECTRICAL  EXPERIMENTER 


July,  1917 


Does  Radiant  Light  Possess  Weight? 

By  a.  r.  Mcpherson 


THE  study  of  light  presents  some  very 
interesting  facts  in  regard  to  that 
mysterious  force  of  Nature,  which 
permits  man  to  view  the  visible  ob- 
jects of  this  material  world,  and  al- 
tho  we  are  still  in  the  dark,  so  to  speak,  as 
to  the  true  nature  of  light,  much  progress 
is  being  made  which  will  perhaps,  even  in 
the  present  generation,  reveal  the  facts 
concerning  light.   The  first  theory  advanced 


conception  that  the  ether,  instead  of  being 
some  mysterious  form  of  non-matter,  as 
generally  believed,  is  actually  the  lightest 
and  the  simplest  of  the  elements,  and  a 
definite  form  of  matter.  He  believes  it  to  be 
one  of  the  inactive  gases  of  the  Argon  fam- 
ily of  elements  and  he  assigns  to  it  the 
position  'X,'  in  the  zero  group  of  his  re- 
vised periodic  arrangement  of  the  elements. 
The  atomic  weight  of  the  ether  he  concludes 


to  the  theories  of  Einstein  and  Norstrom, 
there  should  be  a  real  influence  of  gravita- 
tion on  light.  It  is  asserted  that  the  spec- 
trum lines  of  two  light-rays  originating  in 
gravitation  fields  of  different  strengths  are 
shifted  relatively  to  each  other.  As_  Frem- 
lech  has  now  shown,  the  shifting  is  very 
well  explained,  so  far  as  its  amount  is  con- 
cerned, by  Einstein's  theory.  An  influence 
of  an  impulse  proceeding  from  the  sun,  on 


Is"Liglit,,a  Material  SixKstance  ? 


LIGHT  BEAM 


Prof.  T.  J.  J.  See 's  theory  of  "Light"  -which  says 
that  Light  is  caused  by  electrically  charged 
egg-shaped  particles  revolving  at  enormous  vel- 
ocity about  their  shorter  axes. 


NICOL  PRISM 


POWERFUL  MAGNET  POLES 


POSITION  OF 
LIGHT  RAYS 
(NORMAL -  NO  MAGNET) 


DEFLECTED^ - 
RAY  CAUSED 
BY  MAGNET 


Certain  spectrum  lines  are  altered  in  posixion 
(Zeeman  effect)  by  powerful  magnetic  field. 


CROOKE'S  RADIOMETER 


U  NORMAL. 


Fremlech  as  well  as  Einstein  and . 

Norstrom,  claim  that  the 
Spectrum  lines  of  into  light  raw 
originating  in  gravitation  fields 
of  different  strengths  FjandFz 
are  shifted  relatively  to  each  other 
tending  to  show  thai  light  hasweight. 


The  pressure  of  light 
has  been  measured 
Tt  will  spin  ihe  vanes 
of  the  radiometer 


The  total  "Light 
pressure"  on  the 
earth  has  been  cal- 
culated at  7o,ooo  tons 


ALPHA  RAYS*"Ji\^gg£^"BETA  HAYS" 
fveiociTr^  (velocity  = 

2O.O0OMILES        RADIUM  MORE  THAN  100,000 

PER  SECOND)  MILES  PER  SECONoj 


That  "Light" maybe  a  material 

suhstance, having  weight.  Seems 
possible,  as  it  has  been  proven 
that  the  above  Sadium  rays 
are  actually  streams  of  little 
bodies  having  a  mass  twice 
that  of  the  Hydrogen  atom. 


as  to  the  nature  of  light  was  the  mate- 
rialistic theory,  which  involved  the  idea  that 
light  was  composed  of  material  particles  of 
matter.  This  theory  was  rejected  years  ago, 
but  like  the  alchemists'  dreams  of  the  trans- 
mutation of  matter,  which  it  seems  is  now 
becoming  a  reality,  so  this  materialistic 
theory  is  again  coming  into  favor. 

The  present  generally  accepted  theory 
states  that  light  is  identical  with  electro- 
magnetic disturbances,  such  as  are  generated 
by  oscillating  electric  currents  or  moving 
magnets ;  but  this  must  presuppose  the  ex- 
istence of  an  imaginary  medium  called 
ether,  which  is  supposed  to  pervade  all 
space,  and  is  in  the  interior  of  all  bodies  of 
whatever  nature.  It  is  thin,  elastic,  and 
capable  of  transmitting  vibrations  with 
enormous  velocity.  Every  luminous  body  is 
in  a  state  of  vibration  and  communicates 
vibrations  to  the  surrounding  ether.  This, 
in  short,  is  the  electro-magnetic  ether  theory 
which  has  been  evolved  in  recent  years. 

It  is  the  belief  of  many,  however,  that 
ether,  to  exist  at  all,  must  be  in  a  material 
form  such  as  a  gas,  in  order  to  harmonize 
with  natural .  laws.  To  quote  from  "New 
Knowledge" :  "Mendelieff,  the  Dean  of 
chemical  science,  has  recently  originated  the 


to  be  one-millionth  of  that  of  hydrogen  and 
its  atoms  consequently  travel  with  enormous 
velocities.  This  extreme  velocity  explains 
the  all-pervading  character  of  the  sub- 
stance." 

Prof.  T.  J.  J.  See,  a  scientist  whose  re- 
searches are  known  thruout  the  world,  re- 
cently made  public  the  following  statement 
in  regard  to  light : — "The  whole  theory  of 
ether  is  abandoned  as  having  no  real  exist- 
ence, light  being  caused  by  electrically 
charged  particles,  shaped  like  eggs,  revolv- 
ing about  their  shorter  axes." 

It  would  thus  seem  that  there  is  consid- 
erable difference  of  opinion  about  the  na- 
ture of  light,  and  the  writer  has  endeavored 
to  gather  together  some  of  the  leading 
facts  and  theories  which  tend  to  throw  some 
"light"  on  the  subject. 

If  it  can  be  proven  that  light  has  weight, 
it  must  necessarily  follow  that  it  possesses 
material  form  and  properties.  No  influence 
of  any  form  of  attraction  on  light  had  been 
noticed  until  about  twenty  years  ago,  when 
Zeeman  showed  that  a  powerful  magnet  vis- 
ibly altered  the  position  of  certain  lines  in 
the  spectrum. 

Now  it  appears  that  gravitation  has  a 
similar,  tho  not  the  same  effect.  According 


shifting,  cannot  be  the  cause;  for  in  this 
case,  single  lines  would  be  shifted  in  differ- 
ent degrees.  But  the  measurements  show 
that  the  shifting  of  the  lines,  both  in  amount 
and  direction,  is  the  same  for  all,  as  Ein- 
stein's theory  of  the  influence  of  gravitation 
requires.  The  shifting  of  the  lines  calcu- 
lated with  Einstein's  formula  agrees  re- 
markably well  with  the  average  observed 
values.  The  influence  of  gravitation  on 
light  may  now  be  regarded  as  partially 
proved,  and  thus  it  may  also  be  inferred 
that  light  possesses  weight. 

From  the  above  facts  it  may  be  demon- 
strated and  must  also  be  proven  that  light 
exerts  pressure,  since  it  is  a  material  sub- 
stance possessing  wreight.  This  peculiar 
truth  was  proven  mathematically  as  early 
as  1873  by  Maxwell,  tho  it  was  applied 
then  and  still  is  to  a  certain  extent  in  sup- 
port of  the  electro-magnetic  wave  theory. 
In  1901,  Peter  Lebdew  actually  proved  and 
measured  the  mechanical  pressure  of  light. 
The  pressure  discovered  was  small,  of 
course,  but  the  minuteness  of  a  thing  is 
often  an  inverse  measure  of  its  importance, 
as  this  light  pressure  has  been  found  ade- 
quate to  explain  some  of  the  earth's  greatest 
{Continued  on  page  215) 


July,  1917 


THE  ELECTRICAL  EXPERIMENTER 


69 


War  and  Radio  In  the  Movies 


THE  hero  of  the  realistic  Bluebird 
photoplay — "Treason,"  is  a  Govern- 
ment telegrapher  in  the  service  of  a 
mythical  European  country  at  war 
with  its  neighbor.  He  is  selected  to 
go  to  the  front,  and  this  arouses  the  jealousy 
of  his  chief,  who  regards  it  as  a  personal 
affront.  Pettrus  distinguishes  himself  at  the 
front  as  a  telegrapher,  and  is  invalided 
home.  He  finds,  instead  of  promotion,  that 
he  is  degraded  to  the  position  of  messenger. 
His  chief  has  tampered  with  a  telegram, 
ordering  him  to  spare  Pettrus  as  much  as 
possible. 

He  feels  deeply  the  neglect  of  his  country, 
and  confides  his  feelings  to  his  friend  the 
tobacconist,  who  in  reality  is  a  "spy."  The 
man  sends  information  to  the  enemy  ( top 
view)  by  means  of  wireless  apparatus  con- 
cealed in  a  trunk  in  his  rooms,  (extreme 
right  photo).  He  works  upon  Pettrus'  re- 
sentment until  he  finally  persuades  him  to 
steal  the  new  code  from  the  home  of  the 
Head  of  the  Secret  Service,  with  whose 
daughter  Pettrus  is  in  love.  No  sooner  has 
he  done  so,  than  he  repents,  and  would  give 
anything  to  undo  his  act. 

The  Head  of  the  Secret  Service  has  been 


crimes,  learns  of  the  plans  of  a  group  of 
criminals,  who  are  supposed  to  be  connected 
with  the  murders,  and  in  whose  power  the 
girl  who  he  loves  was  formerly  held. 

The  enemy  having  "captured"  New  York 
City,  in  Greater  Vitagraph's  preparedness 
spectacle  "Womanhood,"  Harry  Morey,  who 
plays  the  part  of  Paul  Strong,  Director  of 
Energies,  U.  S.  A.,  proceeds  to  evolve  a 
plan  by  which  he  can  be  appraised  of  their 
movements  and  act  accordingly. 


vehemently    denounces  her    native  land. 

Paul  Strong,  perceiving  in  Mary's  posi- 
tion an  opportunity  to  strike  a  telling  blow- 
to  the  "enemy,"  accordingly  outfits  a  wire- 
less telephone  contrivance  whereby  Mary, 
thru  her  close  association  with  the  "enemy," 
can  inform  him  of  their  plans  without  in- 
curring their  suspicions.  (See  left  and  lower 
center  photos.)  The  copper  gutters  on  the 
roof  of  the  Woolworth  Building  are  used 
as  antenna.  Mar}-  employs  a  pocket  radio- 
phone instrument,  which  she  connects  with 
the  improvised  antenna,  thru  a  secret  switch, 
cleverly  hidden  in  the  brass  scroll  work  of 
an  electrolier  on  the  side  wall. 


ODDLY  IDENTIFIED  BY  RADIO. 

American  naval  officers  are  highly 
amused  over  a  recent  "wireless  romance" 
connected  with  an  American  destroyer.  The 
story  well  exemplifies  traditionary  sea  cau- 
tion and  hangs  on  the  fact  that  by  reason 
of  two  Americans  having  been  roommates 
at  St.  John's  College  at  Annapolis  years 
ago,  information  was  confirmed  at  sea  that 
otherwise  would  have  remained  doubtful. 

One  man  is  a  civilian  doctor,  who  has 


Mary  Ward  (Alice  Joyce)  the  Heroine  of  the 
War    Film-Play — "Womanhood"    Is  Caught 
Using    Her    Pocket    Radiotelephone  Set. 


watching  the  tobacconist,  whom  he  knows  to 
be  a  spy.  He  now  questions  Pettrus,  who 
finally  confesses.  The  Head  of  the  Secret 
Service  helps  him  to  recover  the  code. 
There  is  a  thrilling  automobile  chase,  which 
ends  in  a  terrific  smash  over  the  side  of  a 
cliff.  The  tobacconist  is  killed,  and  Pettrus 
seriously  injured.  In  the  hospital,  he  re- 
turns the  code  to  the  Head,  who  promises 
that  his  act  shall  be  a  secret  between  them. 
The  woman  with  whom  his  Chief  has  been 
on  terms  of  intimacy  finds  the  doctored  tele- 
gram, and  in  revenge  for  neglect,  exposes 
the  Chief  to  the  Head  of  the  Government 
telegraph  department.  The  delayed  reward 
for  Pettrus'  services  arrives,  and  the  spite 
work  of  his  Chief  is  revealed. 

The  Universal  serial  "The  Voice  on  the 
Wire"  is  concerned  with  a  series  of  mur- 
ders, committed  in  the  same  way,  by  an 
attack  on  the  victim  over  his  heart  which 
leaves  a  bruise  the  size  of  a  human  thumb. 
No  other  clue  is  left  except  a  message  from 
a  mysterious  voice  spoken  over  a  discon- 
nected electric  wire,  which  warns  the  vic- 
tim of  his  end,  and  exults  over  the  detec- 
tives, as  each  time  they  fail  to  circumvent 
it.  In  the  eleventh  episode,  a  strange  inven- 
tion is  introduced.  This  is  a  material  de- 
velopment of  the  science  of  mental  tele- 
pathy. (In  the  "movies,"  they  do  it!)  By 
a  wireless  arrangement,  the  mind  in  control 
can  communicate  with  the  mind  it  influ- 
ences, and  the  machine  is  made  to  register 
the  thought.  By  its  use  (central  view  here 
shown)  the  investigator  who  is  tracing  the 


Top  Center: — A  Stirring  Scene  from  "Trea- 
son," the  Great  Photoplay  of  War,  Radio  and 
Love.  Center  Scene: — A  Moment  from  Uni- 
versale— "The  Voice  on  the  Wire."  Lower 
Center: — Paul  Strong,  Director  of  Energies, 
U.  S.  A.,  in  "Womanhood,"  Receiving  a  Re- 
port from  His  Sweetheart  in  the  Enemy's 
Stronghold    (Extreme    Left)    "Via  Radio." 


His  sweetheart,  Mary  Ward,  played  by 
Alice  Joyce,  is  also  the  object  of  Prince 
Dario's  enamouration.  Count  Dario  is  one 
of  the  commanders  of  the  invading  host  and 
the  son  of  Marshal  Prince  Dario,  the  mili- 
taristic Commander-in-Chief  of  the  Ruri- 
tanians,  the  name  given  the  "enemy." 

Thru  Count  Dario's  influence,  Mary  is 
offered  a  position  in  the  invader's  headquar- 
ters which  is  located  in  the  Woolworth 
Building.  Mary  seeing  in  this  an  oppor- 
tunity to  serve  her  country,  accepts,  and 


Here   You    Have  a   Chance  to   See  a  Spy's 
"Trunk"  Radio  Apparatus  at  Work.    An  Ab- 
sorbing   Moment   from    the    Master  Photo- 
play— "Treason." 

taken  an  important  post  in  Great  Britain, 
the  other  is  a  paymaster  in  the  navy. 
Two  days  before  the  destroyers  sailed  from 
the  United  States  these  old  friends  ate  a 
farewell  dinner.  The  doctor  was  to  sail 
by  a  liner,  but  was  ignorant  of  the  ship's 
name  and  date  of  sailing.  The  paymaster 
was  under  orders  to  join  his  destroyer. 

When  several  days  at  sea  the  destroyer 
got  into  distant  connection  one  night  with 
a  certain  vessel,  and  made  a  code  inquiry 
as  to  the  vessel's  position,  course,  and  speed. 
No  direct  reply  was  made,  the  vessel  fear- 
ing a  submarine  trick  and  the  possibility 
of  a  stolen  codebook.  Instead  of  answer- 
ing a  demand  was  made  to  the  destroyer: 
"Give  the  name  of  your  ship  in  code." 
The  destroyer  complied. 

Even  this  was  not  enough.  A  second 
wireless  was  sent  out :  "What  is  the  name 
of  your  paymaster  who  is  the  friend  of 

Dr.  ,  a  passenger  aboard  this  ship?1' 

Then  the  paymaster  of  the  destrojrer 
was  called  into  the  wireless  cabin  and  asked 
if  he  knew  Dr.   .  "Sure,"  he  re- 
plied. "He  was  my  best  pal.  We  were 
roommates  at  college,  and  had  dinner  to- 
gether two  nights  before  I  sailed.  Where 
is  he?" 

The  destroyer  sent  out  another  radio, 

saying:  "Paymaster  ,  the  doctor's 

oldest  friend." 

After  this  corroborative  statement  the 
vessel  at  last  gave  her  position,  course, 
and  speed. 


170 


THE  ELECTRICAL  EXPERIMENTER 


July,  1917 


U.  S.  Battleships  to  Run  on  Land 

By  H.  GERNSBACK 


EVERY  war  brings  out  a  host  of 
fantastic  as  well  as  ridiculous  new 
inventions  which  are  supposed  to 
annihilate  the  enemy.  Most  of 
these  wild-cat  schemes  are  of  course 
as  impractical  as  they  are  fantastic,  and 
while  they  look  good  on  paper,  the  devices 
do  not  stand  up  in  practise,  either  because 
of  inherent  defects  or  because  science  and 
technic  have  not  progrest  sufficiently  to 
do  justice  to  the  device. 

Thus  a  submarine  invented  by  no  less 
a  genius  than  Robert  Fulton,  propelled  by 
several  men  and  which  was  actually  run 
under  water,  was  sanctioned  by  Napoleon, 
the  inventors  hoping  to  sink  the  blockading 
English  fleet.  The  submarine  failed  miser- 
ably, to  Napoleon's  utter  disgust.  Never- 
theless the  failure  was  not  due  to  the 
principle  being,  inherently  wrong.  Rather 
science  had  not  progrest  sufficiently  to 
make  the  submarine  a  success  one  hun- 
dred years  ago.  Napoleon,  if  he  were  to 
come  back  today,  would  certainly  -experi- 
ence a  radical  change  of  mind,  as  to  the 
success  of  the  submarine. 

In  the  same  manner,  when  John  Ericsson 
constructed  the  "Monitor"  in  1862,  he  was 
met  with  a  good  deal  of  ridicule — at  first. 
No  one  believed  that  his  steel  "cheese- 
box  on  a  raft,"  war  vessel  could  do  much 
damage,  or  even  give  a  good  account  of 
itself,  let  alone  winning  a  battle.  The  world 
knew  different  after  the  "Monitor"  defeated 
the  famous  "Merrimac." 

Makeshifts  have  been  used  in  every  war, 
and  every  important  battle  has  them. 
Sometimes  these  makeshifts  actually  prove 
decisive  in  a  battle,  perhaps  for  the  simple 
reason,  that  insofar  as  they  usually  con- 
tain the  element  of  surprise,  the  enemy,  not 
being  prepared  for  the  unusual  onslaught 
is  defeated. 

Perhaps  the  most  famous 
instance  where  a  big  battle 
was  won  with  a  makeshift 
was  the  Battle  of  the  Marne, 
in  1914.  No  more  impos- 
sible or  ridiculous  weapon 
than  an  ordinary  taxicab 
could  be  imagined  to  launch 
a  modern  army,  equipt  with  j 
the  world's  best  artillery.  ^ 
Nevertheless,  when  the  de- 
fender of  Paris,  General 
Gallieni,  requisitioned  every 
Paris  taxicab,  and  flung 
these  thousands  of  squeaky 
vehicles,  which  had  never 
been  designed  for  such  work, 
against  the  German  hordes, 
they  simply  had  to  give  way ; 
and  the  taxicabs  won.  One  of 


paralleling  tracks,  under  a  ship.  This  car, 
after  the  ship  was  made  fast  to  it  in  a 
suitable  manner,  was  then  to  be  drawn  over- 
land— over  the  present  Panama  Canal 
route — by  powerful  locomotives. 

Lately  other  plans  have  appeared  show- 
ing battleships  running  thru  cities  and  over 


hind  her  mine  fields  and  bides  her  time. 

But  the  U.  S.  navy  has  a  number  of 
battleships  of  the  pre-dreadnought  type, 
good  ships  as  yet,  but  obsolete  as  first- 
line  ships.  I  refer  to  ships  of  the  Ore- 
gon, Iowa,  Illinois,  Kentucky,  Massachu- 
setts, Indiana  class.  These  ships  are  fully 
equipt  now,  have  good  crews  and  good 
guns.  But  the  chances  are  that  ten  years 
from  now  they  will  be  used  as  targets 
or  otherwise  will  be  relegated  to  the  scrap- 
heap.  So  why  not  send  these  ships  to  the 
front?    Briefly,  the  idea  is  this: 

Let  us  send  these  ships,  men,  guns  and 
all,  to  France.  In  the  holds  of  the  ves- 
sels we  pack  channel  irons  and  T,  as  well 
as  I  steel  beams,  cut  to  the  right  length 
before  sailing.  These  pieces  are  fashioned 
much  after  the  structural  toy  steel  pieces 
— you  can  make  almost  anything  out  of 
them. 

When  our  battleship  arrives  in  France, 
it  is  put  immediately  into  dry  dock,  and 
the  crew  at  once  proceeds  to  make  the 
wheels  from  the  channel  steel.    These  huge 
wheels  measuring  over  50  to  60  feet  in 
height,  are  made  on  the  plan  of  a  Ferris 
wheel,  light  but  strong.    Of  course  to  sus- 
tain a  weight  of  10,000  tons  or  more,  a 
set  of  single  wheels  won't  do.    Rather  each 
wheel  is  fashioned  of  a  number  of  wheels 
from  five  upwards,  paralleling  each  other, 
as  graphically  shown  on  our  front  cover, 
and  the  accompanying  illustration.  These 
separate  wheels  are  bolted  or  riveted  to- 
gether by  means  of  steel  "I"  beams  run- 
ning over  the  circumference  of  the  sepa- 
rate wheels.    The  latter  are  strengthened 
by  additional  cross-truss  work,  as  seen  in 
illustration.     Thus  a  very  light,  as  well 
as  powerful  wide  wheel  is  formed.  With 
a  little  previous  drilling,  the  crew  should 
be  able  to  construct  the 
necessary  six  wheels  in  less 
than  one  week — yes,  it  can 
be  done ;  providing  the 
pieces  are  cut  to  the  right 
dimensions  at  home. 

Next  the  thirteen  inch  hol- 
low steel  shaft  is  consid- 
ered. This,  of  course,  has 
been  brougbt  from  America 
too.  The  hollow  shaft  is 
advised,  first  because  it 
weighs  less,  and  second  be- 
cause such  shafts  are  equally 
as  strong  as  solid  ones, 
within  a  reasonable  propor- 
tion. 

The  two  wheels  at  the 
stern  are  "idlers,"  the  same 
as  the  front  wheels  on  an. 
automobile.     No  power  is 

the  world's  greatest  retreats  Puttir)g  wheels  on  Our  Battleships  and  How  It  Is  Accomplish^  The  Wheels  applied  to  them  they  simply 
was  mainly  due  to  these  Here  Shown  Are  Fashioned  of  Angle  and  I  Steel  Beams,  on  the  Plan  of  Structural  rotate  on  the  shaft,  extend- 
peaceful  fare-eaters  Per-  Steel  Toys.  Such  Wheels  Are  Tremendously  Strong.  Slow  Running  Electric  jng  from  one  wheel  to  the 
haps  taxicabs  will  never  be  Motors  CouPled  t0  the  steel  shafts  Drive  the  New  Monster  Over  Land.  other>  dear  th      the  sh;p_ 


used  again  in  such  a  man- 
ner, but  at  any  rate  they  did  their  full  duty 
once.  The  experiment  proved  worth  while. 

Therefore  when  I  propose  to  run  battle- 
ships over  land,  I  am  fully  aware  of  the 
ridicule  I  will  be  subject  to.  I  am  also 
aware  of  all  the  objections  that  will  be 
cited  against  the  fantastic-appearing  plan. 
Nevertheless,  I  insist  that  the  idea  is  not 
half  as  impractical  as  it  may  appear  at 
first.  And  at  any  rate  I  believe  I  have 
found  a  way  showing  how  it  may  be  done 
in  a  simple  manner.  I  give  the  idea  to  the 
country  for  what  it  is  worth. 

I  do  not  claim  to  be  the  originator  of 
the  idea  to  run  battleships  or  other  ships 
over  land.  That  idea  is  old  already.  Twen- 
ty-five years  ago  there  was  published  in  a 
German  weekly  an  idea  to  run  a  power- 
ful car,  moving  over  a  dozen  closely  spaced 


the  houses,  but  no  one  volunteered  to  show 
how  it  might  be  accomplisht.  A  battle- 
ship weighs  anywhere  from  10,000  tons 
upwards— quite  a  respectable  weight.  How 
then  can  we  run  such  a  monster  on  land? 
How  can  it  be  propelled  ? 

Now  that  we  are  at  war,  our  first  duty 
is  to  help  our  allies,  and  to  help  them 
quickly.  The  time  is  too  short  to  build 
new  colossal  war  engines  which  could  be  ■ 
used  at  the  front  at  once.  Our  army  will 
not  be  fully  ready  till  a  year  from  now. 
Our  navy  cannot  help  very  much  on  sea. 
For  if  the  British,  French  and  Russian 
navies,  which  are  at  least  four  times  as 
powerful  as  the  German  navy,  cannot  de- 
stroy the  latter,  the  addition  of  our  own 
navy  will  not  matter  much  one  way  or  an- 
other.   The  German  navy  simply  stays  be- 


The  two  small  center 
wheels  are  also  idlers.  They  serve  to  take 
up  undue  shocks,  which  might  break  the  ship 
in  two,  when  negotiating  difficult  terrain. 

The  two  front  (bow)  wheels  are  the 
"drivers".  They  are  bolted  solid  to  the 
shafts,  two  of  the  latter  being  used  as 
will  become  apparent  at  once.  Our  illus- 
tration shows  that  the  two  shafts  revolve 
in  a  common  bearing  (which  might  be  an 
old  reconstructed  gun  barrel).  Each  shaft 
in  turn  is  directly  coupled  to  a  slow-run- 
ning electric  motor  armature,  as  clearly 
shown.  And  this,  by  the  way,  is  the  much 
discust  electrical  drive,  adopted  in  our 
latest  monster  battle  cruisers,  now  being 
constructed.  From  this  it  becomes  ap- 
parent how  the  land  battleship  is  propelled 
overland  in  a  simple  and  practical  man- 
(Continucd  on  page  216) 


July,  1917 


THE  ELECTRICAL  EXPERIMENTER 


71 


The  Marvels  of  Radio-Activity 


First  Paper  of  a  New  Series 

THE  subject  of  Radio-activity  deals, 
not  only  with  Radium  as  many  be- 
lieve, but  with  a  whole  class  of  sub- 
stances, the  best  examples  of  which 
are    Radium,    Uranium,  Thorium, 
Actinium,  and  the  chemical  compounds  of 
these  substances.  Radio-activity  is  the  name 
given  to  the  prop- 
erty which  these 
substances  have 
O.f  giving  off  or 
emitting  certain 
radiations  spon- 
taneously, these 
rays   having  the 
power  to  pene- 
trate thru  matter 
which  is  opaque 
to  ordinary  light.  | 

History. 

Shortly  after 
the  discovery  of 
X-rays  and  their 
properties  by 
Professor  Ront- 
gen  in  1895,  many 
students  of 
physics  began  to 
investigate  the 
different  phos- 
phorescent bodies 
to  ascertain 
,wh  ether  they 
iwould  or  not  emit  rays  of  the  same  char- 
acter. Professor  Henri  Becquerel,  a  Paris 
physicist,  discovered  in  1896  that  the  com- 
pounds of  Uranium  which  had  a  phosphor- 
escence (that  is,  they  would  glow  in  the  dark 
after  exposure  to  daylight)  would  weakly 
affect  a  photographic  plate.  He  then  found 
that  salts  of  Uranium  which  were  not  phos- 
phorescent also  affected  a  plate,  thus  show- 
ing that  it  was  the  element  Uranium  which 


By  JEROME  S.  MARCUS,  B.  Sc.  (Ch.  E.) 

discharge  electrified  bodies,  produce  phos- 
phorescence in  certain  other  bodies,  and 
penetrate  many  things  that  ordinary  light 
would  not.  Fig.  1.  (Experiments  on  these 
points  will  be  given  later.)  These  rays 
■  were  named  after  their  discoverer,  "Bec- 
querel rays."  It  was  also  found  that  in 
carrying    these     ray-emitting  substances 


Gold  Bar,  About  the  Si 
Size  of  a  Match,  Worth 
Mint, 


Polonium  is  an  element,  but  it  accompanies 
the  Bismuth  in  the  ore,  and  is  separated 
from  it. 

The  discovery  of  these  substances  was 
made  in  1898  and  in  1899,  M.  Debierne  dis- 
covered another  radio-active  material  which 
he  called  "Actinium,"  and  which  follows  the 
iron  in  the  pitchblende  and  seems  to  be 
connected  with 
the  Thorium. 

It  has  been 
shown  by  recent 
investigators  that 
almost  a  1 1  sub- 
stances in  nature 
are  more  or  less 
radio-ac- 
tive. Among 
these  are  freshly 
fallen  rain  or 
snow,  many 
spring  waters, 
etc.  From  this, 
the  idea  has  been 
advanced  that 
radio-activity  i  s 
due  to  certain 
radiations  from 
the  sun  itself. 
These  are  sup- 
posed to  be  con- 
nected w  i  t  h  the 
appearance  of  the 
Aurora  Borealis 
and  other  phe- 
nomena of  atmospheric  electricity.  In  the 
spring  of  1903,  Professor  J.  J.  Thomson 
discovered  that  waters  from  deep  wells  con- 
tained a  certain  gas  which  was  radio-active, 
and  other  substances  are  being  found  which 
also  possess  the  power  of  radio-activity. 
*      *  # 

Becquerel  showed  that  the  rays  from 
Uranium,  like  the  X-rays,  were  capable  of 
discharging  an  electrified  body,  when 
charged  either  positively  or  negatively. 
(Experiment — A  gold  leaf  electroscope  is 
charged  by  touching  to  any  source  of  static 
electricity,  e.  g.,  a  glass  rod  rubbed  with 
silk.     An    Uranium   compound — any  salt 


Top: — Discharging   an    Electroscope   by  Ra- 
dium.    Lower  Illustration  Shows  a  "Radium 
Light"  Which  Will  Give  Sufficient  Illumina- 
tion to  Read  By. 

possest  the  peculiar  ray-emitting  property. 

It  was  then  found  that  these  rays  or 
radiations  of  Uranium,  like  X-rays,  would 


ze  of  an  Ordinary  Building  Brick,  Worth  $18,263.53.  Tube  of  Radium  the 
$18,000.00  (150  Milligrams  at  $120.00  Per  Milligram).  Photographed  in  the 
at  Denver,  to  Show  Relative  Value  of  Gold  to  Radium. 

around  in  one's  pocket,  burns  which  are 
very  hard  to  heal  are  caused,  known  as 
"Becquerel  burns." 

Investigation  of  these  radiations  were 
immediately  taken  up,  especially  by  E. 
Rutherford,  then  a  student  in  the  laboratory 
of  J.  J.  (now  Sir)  Thomson  at  Cambridge, 
England.  Their  properties  will  be  dis- 
cust  later. 

Mme.  Curie,  of  Paris,  made  a  system- 
atic investigation  of  a  large  number  of 
substances   to   test   whether   they  possest 
the  same  rays  as  Uranium.    At  about  the 
same  time,   in    1898,   she   and  Professor 
Schmidt  discovered  that  Thorium  and  its 
compounds  were  radio- 
active.   Mme.  Curie  and 
her  husband  then  began 
an  exhaustive  investigation 
of    the    Uranium  com- 
pounds, and  found  that  the 
activity  was  an  atomic 
property,  i.e.,  it  was  propor- 
tional  to   the   amount  of 
Uranium  present.  While 
working  on  this  basis  with 
pitchblende,    an    ore  from 
Joachimsthal,  Austria,  which 
contains  Uranium,  she  found 
that  the  activity  was  four  or 
five  times  greater  than  it 
should  be.   This  led  her  to  the 
conclusion  that  there  must  be 
something  else  with  stronger 
properties  than  the  Uranium. 
The   Austrian  Government 
placed  a  large  amount  of  the 
ore  at  her  disposal,  and  she 
set  about  separating  the  ex- 
tremely small  amount  of  this 
then  unknown  substance.    Her  efforts  were 
finally  rewarded  by  the  isolation  of  "Polo- 
nium" and  a  substance  of  such  intense  ray- 
giving  power  that  she  termed  it  "Radium." 
Radium  bromide  has  about  two  million  times 
the  activity  of  Uranium. 

Radium  has  been  found  to  be  an  element 
of  definite  atomic  weight,  and  accompanies 
the  Barium  which  is  separated  from  the 
pitchblende.    It  is  not  proved  as  yet  whether 


Remarkable  Photograph  of  the  "Alpha"  Rays  of  the  Ra- 
dium Emanation.     By  C.  T.  R.  Wilson. 

purchased  from  a  chemical  house,  the  au- 
thor uses  Uranyl  chlorid  in  his  experi- 
ments— is  then  brought  near  the  knob. 
The  leaves  are  seen  to  collapse.  (Fig.  1.) 
This  property  of  radio-active  substances  is 
used  as  a  delicate  quantitative  test  for  the 
amount  and  intensity  of  radiation.  A  spe- 
cial electroscope  has  been  devised  for  work 
in  Radium  research,  the  rate  of  collapsing 
{Continued  on  page  207) 


72 


THE  ELECTRICAL  EXPERIMENTER 

Back  to  the  Days  of  "Volta" 


July,  1917 


VOLTA,  inventor  of  the  first  electric 
battery,  after  whom  the  standard 
International  unit  of  electrical  pres- 
sure— the  volt — is  named,  was  one 
of  the  early,  most  brilliant  and  inde- 
fatigable workers  in  the  realm  of  pure  elec- 
trical science.  He  was  born  in  Como,  Italy, 
Feb.  18,  1745,  in  a  house  which  had  been  the 
homestead  of  the  Volta  family  for  over 
300  years.  Paradoxical  as  it  may  seem, 
true  genius  is  often  linked  with  less  brilliant 


knowledge,  had  him  write  essays  on-  elec- 
tricity for  the  great  men  of  the  day,  as 
people  in  general  knew  very  little  about  this 
mysterious  force  at  that  early  period. 

The  first  formal  scientific  papers  of  Volta 
were  issued  in  his  24th  year  and  fourteen 
years  later  there  appeared  his  electrophones 
(see  illustration,  Fig.  1.)  followed  by  his 
electroscope.  The  photographs  here  repro- 
duced show  the  now  historic  apparatus 
built  and  used  by  Volta  in  his  laboratory. 


dium  production  companies  employ  this 
method  in  testing  their  products.  Fig.  1  also 
shows  various  plate  condensers,  invented 
by  Volta. 

While  professor  of  physics  at  Pavia,  he 
conducted  experiments  which  led  to  the 
discovery  of  the  Voltaic  pile.  One  of  the 
accompanying  illustrations,  Fig.  4,  shows 
one  of  the  most  remarkable  historic  docu- 
ments extant — the  original  letter,  written  in 
French,  of  Alessandro  Volta  addrest  to  the 


v-         .  .  •  • 


^  Wv/fy^fJ  fc/ptfai*,.  V3dfo6&>*ur  £ 

■  Cr&ty**',  'r**  ft1       -  Wt£ 


;  a~r  'iff'*?' 'exif'r&t  /o~i  ■: 


Fig.  1 — Alessandro  Volta,  Dean  of  the  Early  Electrical  Inventors  Con- 
ducted Hundreds  of  Experiments  with  Static  Electricity.    This  Photo 
Shows  Several  of  the  Original  Apparatus — Disk  Condenser,  Electro- 
 scope,  Etc., — Used  by  Him.  

Fig-  2 — Static  Electric  Apparatus  which  Belonged  to  Volta.  The  Appa- 
ratus on  the  Right  Served  to  Produce  a  Static  Spark  by  the  Friction  on 

 a  Strip  of  Parchment,  As  It  Was  Rapidly  Reeled  Up.  

Fig.  3 — Volta's  Original  Apparatus:    At  Right — Device  for  Igniting  Mix- 
ture of  Hydrogen  and  Oxygen  by  a  Static  Spark.     Left — Instrument 
for  Demonstrating  Electric  Theory  of  Hail. 


Fig.  4— The  Highly  Prized  Original  Letter  Written  by  Volta  to  the 
Royal  Society  of  London  Describing  His  First  Battery — the  "Voltaic 

Pile." 


traits  of  character,  and  as  a  child  we  are 
told  that  Alessandro  Volta  was  very  back- 
ward. Even  to  the  point  that  he  could  only 
speak  one  word  "No,"  when  he  had  reached 
his  fourth  birthday. 

But,  like  many  other  great  scholars  of 
the  world,  he  suddenly  developed  a  great 
affinity  for  philosophy  and  became  an 
earnest  student  of  scientific  subjects,  espe- 
cially the  natural  wonders  of  nature — par- 
ticularly electricity.  When  he  was  17  years 
old  he  had  won  prizes  in  philosophy  and  at 
18,  the  famous  Abbe  Nolet.  strongly  im- 
prest with  the  youth's  superior  and  divining 


Fig.  1  shows  a  variety  of  electro-static 
apparatus,  including  a  static  electric  charg- 
ing device — the  electrophorus,  at  extreme 
left,  and  the  detector  of  static  charges — the 
electroscope  at  extreme  right.  Both  of  these 
devices  are  still  in  use  in  electrical  labora- 
tories where  the  elements  of  pure  science 
are  studied.  Besides,  the  electricians  of  to- 
day have  found  many  practical  applications 
for  the  electroscope,  never  even  dreamed  of 
by  the  illustrious  Volta.  One  important 
commercial  and  highly  important  applica- 
tion of  the  sensitive  electroscope  is  in  the 
measurement  of  radio-activity.     The  Ra- 


Societe  Royale  de  Londres  describing  his 
new  electric  battery  (Voltaic  pile),  consist- 
ing of  alternate  zinc  and  copper  discs  sepa- 
rated by  dampened  blotter  paper  sheets. 
This  formed  the  basis  of  present-day  elec- 
tric batteries.  There  is  no  doubt  that  mod- 
ern electricity  really  starts  with  this  famous 
letter.  For  it  was  Volta's  battery  that  pro- 
duced the  very  first  electric  galvanic  mark. 
It  was  Volta  who  led  the  first  galvanic  cur-' 
rent  thru  a  wire.  And  it  was  his  battery 
that  produced  for  the  first  time  useful 
dynamic  electricity. 

(Continued  on  page  212) 


July,  1917 


THE  ELECTRICAL  EXPERIMENTER 


173 


X-RAYST 


In  Child-hood  Days  We 
Used  to  Enjoy  Reading 
About  the  Two  -  headed 
Giants  Who  Strode  Over 
the  Land  with  Seven 
League  Boots.  But  Here 
We  are  Face  to  Face 
with  a  Real  Two-headed 
Human  Being.  The  X- 
Ray  Shows  the  Two  Dis- 
tinct Spines  Very  Clearly. 
(Photo  from  Dr.  W. 
B.  Snow.) 


"I  Never  Eat  Shad  Because  It  Has  so  Many  Bones"— That's 
What  They  All  Say.  Speaking  of  Fishes,  Ladles  and  Gentle- 
men, Meet  This  Rotund  Member  of  the  Finny  Tribe  in  All  His 
Glory  of  Bones  of  Every  Shape  and  Size.  What  the  X-Ray 
Reveals. 


Remarkable  X-Ray  Photo  of  »  Four-Legged  Chicken.  Five  Hours  Old     Now  That  the 
High  Cost  of  Living  Is  Our  Dally  Topic  It  Is  Pleasant  to  Note  That  Nature  Comes  to 
Our  Aid  and  Beats  the  Poultry  Trust  to  It.    "Mom,  I  Want  the  Western  Hind  Lea" 
WIN  Soon  Be  Heard  All  Over  the  Country.    Photo  G    E  R 


On  Another  Page  There  is  an  Article  on  Prof.  Miller's  Great 
Researches  on  Sound.    Here  You  Have  a  Chance  to  Meet  That 
Scientist,  and  as  You  See.   He  Wishes  to  Conceal  Nothing 
from  You.    One  of  the  Most  Wonderful  X-Ray  Photos  Ex- 
tant,   Showing   As    It    Does  the 
Entire  Human  Body,  Clothes  and 
All.     Note    the    Watch.  Keys, 
Pocketbook,  Etc. 


Did  You  Believe  That  the  New-born 
Child  Had  No  Bones?  Here's  Evidence 
to  Prove  That  the  Stork's  Gift  Is  100 
Per  Cent  Complete  in  His  Physical 
Structure. 
(Photo  Dr.  W.  B.  Snow.) 


Are  You  a  Mason? 
If  You  Are  Not,  Per- 
haps You  Can  Figure 
Out  What  Mystic  Or- 
der the  Gentlemen 
Posing  for  This  Skia- 
graph Belonged  to. 
Note  the  Twisting  of 
the  Wrist  Joints  Due 
to    Clasping  Hands. 

(Photo  from   Dr.  W. 
B.  Snow. 


1  74 


THE  ELECTRICAL  EXPERIMENTER 


July,  1917 


Lightning — How  to  Protect  Yourself  From  It 

By  W.  G.  WHITMAN,  State  Normal  School,  Salem,  Mass. 


1IGHTNING,  that  awe-inspiring  nat- 
ural phenomenon  which  compels  the 
attention  of  child  and  adult  alike, 
-J  is  the  cause  of  about  800  deaths 
and  of  1,500  injuries  sustained  by 
the  people  of  the  United  States  in  a  single 
year.  It  also  causes  the  destruction  of 
many  millions  of  dollars  worth  of  property 
yearly. 

Lightning  is  a  more  vital  subject  in  the 
country  and  small  village  than  in  the  city. 
It  is  rare  that  lightning  strikes  in  the  large 
towns  or  cities.  The  isolated  building  or 
object  is  in  greatest  danger.  The  subject 
is  of  varying  economic  importance  too  in 
different  states.  Records  show  that  light- 
ning does  more  damage  in  Iowa  than  in 
any  other  state.  Maryland,  Wisconsin, 
New  York,  Ohio  and  Illinois  follow  in  the 
amount  of  damage  received  from  this 
source. 

That  the  harmless  spark  obtained  by  rub- 
bing .a  cat's  fur  in 
cold  winter  and  the 
terrifying  lightning 
of  a  hot  summer  day 
are  closely  related, 
belonging  as  they  do 
in  the  same  family  of 
natural  phenomena, 
has  never  been  sur- 
mised by  the  average 
school  pupil.  In  fact 
many  older  people 
have  not  thought  of 
them  as  related  phe- 
nomena, even  tho 
Franklin  proved  their 
identity  in  1752. 

Benjamin  Franklin 
while  experimenting 
with  electricity 
noticed  certain  resem- 
blances between  the 
sparks  produced  arti- 
ficially and  the  nat- 
ural lightning.  Both 
flashes  were  instan- 
taneous ;  gave  intense 
light  ;  followed  a 
crooked  path  ;  pro- 
duced noise ;  set  com- 
bustible material  on 
fire  and  killed  animals. 
From  observation  of 
the  similar  behavior 
of  the  two,  he  was  led 
to  a  strong  belief  in 
their  identity,  so  he 
determined  to  per- 
form some  experiment 
which  would  prove 
their  likeness  or  un- 
likeness.  And  on  July 
4,  1752,  he  sent  a  kite 
into  the  clouds  during 
a  thunder  storm  and 
succeeded  in  bringing 
electrical  energy  from 
the  cloud  thru  the  kite 
string  to  a  key  at  its 
lower  end.  This  string 
and  key  were  insu- 
lated from  the  earth 
by  a  silk  cord.  Frank- 
lin obtained  sparks 
from  the  key  just  like 
those  he  had  produced 
in  his  laboratory,  thus 
did  he  demonstrate  to 
the  world  the  fact  that 
lightning  is  an  electrical  discharge. 

The  boy  who  shuffles  his  feet  over  the 
carpet  and  draws  a  spark  from  the  water 
faucet  or  gas  burner  is  a  dynamo  un- 
awares ;  he  generates  electricity  and  dis- 
charges it  at  a  pressure  of  thousands  of 
volts. 

It  is  usuallv  true  that  the  air  above  the 


earth  is  positively  electrified  and  that  the 
earth  differs  in  electrical  pressure  from  all 
space  around  it  by  many — possibly  150,000 
volts.  It  is  not  constant,  however;  con- 
ditions are  always  changing  and  the  elec- 
trical tension  is  variable.  Such  a  difference 
of  potential  as  this  is  not  sufficient  to  pro- 
duce lightning. 

When  clouds  are  rapidly  formed  by  air 
currents  rising  into  the  air,  enormous  quan- 
tities of  electricity  are  produced.  We  do 
not  know  exactly  how  it  is  produced.  The 
latest  theory,  that  of  Dr.  Simpson,  explains 
the  electrification  as  resulting  from  the 
splitting  of  rain  drops  into  smaller  particles 
as  they  tend  to  fall  thru  a  rapidly  rising 
current  of  air.  In  some  way  clouds  do  be- 
come highly  charged  with  electricity. 
Sometimes  they  are  positively  charged  and 
sometimes  negatively  charged.  When  two 
clouds  or  a  cloud  and  the  earth  are  at  suf- 
ficiently great  difference  of  potential  the 


That  All 


Thousands  of  Cattle  on  the  Great  Farms  of  the  West  Are  Annually  Electrocuted  by 
Lightning   Discharges  Which  Charge  "Ungrounded"   Metal   Fences  and   Demolish  "Un- 
rodded"    Barns    and    Outbuildings.      The    Highest    Authorities  Recommend 
Buildings  Be  Equipt  With  Proper  Lightning  Rods. 

resistance  of  the  intervening  air  is  over- 
come and  a  discharge  takes  place  producing 
the  common  phenomenon  of  lightning.  Sir 
Oliver  Lodge  calculated  that  a  flash  of 
lightning  one  mile  long  is  probably  due 
to  a  difference  of  potential  of  5,000,000,000 
volts,  but  it  is  generally  thought  now  that 
this,  figure  is  too  high.     Trowbridge  has 


found  that  a  difference  of  potential  of 
about  25,000  volts  between  battery  terminals 
will  give  a  one-inch  spark  thru  air. 

The  duration  of  a  flash  of  lightning  is 
usually  under  1/50,000  second  and  may  be 
only  1/1,000,000  second.  Because  of  per- 
sistence of  vision  we  apparently  see  the 
flash  for  a  longer  time.  According  to  cal- 
culations made  by  Lodge,  a  discharge  from 
a  cloud  10  yards  square,  fully  charged,  at 
a  height  of  one  mile,  liberates  2,000  foot- 
tons  of  energy.  This  energy  is  enough  to 
warm  2^4  quarts  of  water  to  the  boiling 
point  and  then  change  it  to  steam  in  a 
trifling  part  of  a  second.  Such  intense  heat 
warms  the  particles  of  air  to  incandescence 
and  is  the  cause  of  the  flash  seen.  Heated 
air  conducts  electricity  better  than  cold  air, 
so  at  times  other  flashes  will  follow  in  the 
path  of  the  first  one  before  the  air  has 
become  cold.  These  multiple  or  oscillating 
flashes  may  continue  for  1/1,000  to  1/200 
second,  but  altogether 
they  apparently  make 
but  one  flash  to  the 
eye. 

The  discharge  of 
this  cloud,  10  yards 
square,  gives  enough 
energy,  in  1/20,000  of 
a  second,  if  properly 
directed,  to  hurl  1,000 
barrels  of  flour  20 
feet  into  the  air.  When 
this  energy  heats  the 
air  in  the  path  of  the 
lightning  discharge  it 
causes  sudden  expan- 
sion with  explosive 
violence  and  when  the 
expanded  air  cools  and 
contracts  a  vacuum  is 
formed,  into  which  air 
rushes  again  with  im- 
plosive  force.  When 
you  blow  up  a  rubber 
balloon  to  an  exces- 
sive pressure,  explo- 
sion results  with  a 
loud  sound.  When  an 
incandescent  bulb  is 
broken,  air  rushes  in- 
to the  space,  and  when 
it  meets  it  produces  a 
loud  sound  from  the 
implosion.  These  two 
cases  illustrate  the 
production  of  thun- 
der. One  part  of  a 
lightning  flash  may  be 
a  mile  farther  away 
from  you  than  the 
nearer  part.  The 
thunder  from  the 
more  distant  part  will 
reach  you  about  5  sec- 
onds later  than  that 
from  the  nearer  part. 
Thus  while  a  flash 
may  be  instantaneous, 
the  thunder  which 
you  hear  may  be  of 
considerable  duration. 
Thunder  from  several 
flashes  may  unite. 
Thunder  may  be  re- 
flected by  one  or  more 
clouds.  In  these  ways 
the  rumblings,  char- 
acteristic of  thunder, 
are  produced. 
Objects  standing  on  the  surface  of  the 
earth  become  a  part  of  it  and  are  electri- 
cally charged  the  same  as  the  earth.  Stand- 
ing" above  the  earth's  surface  they  _  form 
excellent  discharge  points_  since  the  air  gap 
from  them  to  the  cloud  is  less  than  from 
the  surrounding  earth  to  the  clouds,  and 
furthermore,  the  electrical  density  or  ten- 


July,  1917 


THE  ELECTRICAL  EXPERIMENTER 


175 


sion  is  greater  at  points,  corners  and  angles 
than  on  surfaces.  Whatever  the  object  may 
be  thru  which  the  discharge  starts,  it  in- 
stantly becomes  the  conductor  thru  which 
electricity  passes  either  to  or  from  a  large 
area  surrounding  it.  If  an  object  only  dis- 
charged an  amount  of  electricity  equal  to 
that  which  it  held  before  the  discharge, 
there  would  be  little  danger  or  violence,  but 
when  it  becomes  the  conductor  to  carry  the 
electricity  of  a  consid- 
erable portion  of  the 
earth  about  it,  the  large 
quantity  of  electricity 
passing  in  so  brief  an 
interval  causes  violence 
and  damage. 

A  similar  discharge 
of  the  earth  occurs 
when  an  object  on  the 
earth  is  electrified  by  a 
near-by  cloud  by  induc- 
tion and  a  discharge 
passes  between  them. 
The  discharges  at  the 
storm  front  are  usually 
the  most  severe.  After 
the  first  few  discharges 
the  air  seems  to  become 
a  better  conductor  and 
the  lightning  is  less 
severe. 

Any  high  object 
reaching  above  the 
earth  carries  the  elec- 
trostatic field  nearer  to 
that  of  the  cloud,  thus 
increasing  the  possibil- 
ity of  an  electrical  dis- 
charge between  them. 
The  tremendous  heat 
energy  which  is  pro- 
duced from  the  electri- 
cal discharge  of  a  large 
cloud  highly  charged  is 
sufficient  to  heat  air 
particles  to  incandes- 
cence, to  melt  minerals 
and  metals,  to  vaporize  solids  and  liquids 
with  explosive  violence  and  to  set  fire 
to  combustible  matter.  It  is  little  won- 
der that  trees  are  splintered  and  buildings 
set  on  fire  when  they  make  a  path  for  the 
lightning  to  the  earth — or  from  the  earth— 
for  it  is  believed  that  fully  as  many  dis- 
charges are  from  the  earth  to  the  clouds 
as  from  the  clouds  to  the  earth. 

Protection  against  lightning  is  needed  on 
isolated  buildings,  tall  chimneys,  steeples 
and  flag  poles.  Such  protection  is  secured 
by  use  of  a  nvetal  cage  or  series  of  rods 
with  high  points  and  the  whole  thoroly 
grounded.  The  material  must  be  of  suf- 
ficient capacity  to  carry  off  large  quantities 
of  electricity  and  it  must  not  corrode 
readily.  Copper  and  galvanized  iron  are 
the  two  metals  most  commonly  used  for 
lightning  rods.  The  lightning  rods  or  con- 
ductors should  not  be  insulated  from  the 
building  because  the  object  of  the  rods  is 
to  drain  electricity  from  all  objects  about 
or  a  part  of  the  building.  Conductors 
ought  not  to  be  placed  near  or  parallel  to 
an  inside  pipe,  because  the  discharge  might 
jump  thru  the  wall  to  it,  causing  fire,  or 
it  might  produce  a  powerful  heating  effect 
in  it,  resulting  from  induction.  A  safe- 
guard against  such  a  disaster  is  to  connect 
the  lightning  rod  system  at  the  highest  and 
at  the  lowest  points  with  inside  structural 
beams  and  water  pipes.  Sometimes  gas 
pipes  are  connected  but  because  of  the  in- 
flammability of  gas,  many  prefer  not  to 
connect  them.  All  exterior  metal  work  of 
the  building,  as  gutters,  railings,  etc.,  either 
should  be  connected  to  the  lightning  rod  at 
a  level  below  their  own  or  they  should  be 
grounded  by  a  separate  cable.   The  ground- 


ing of  lightning  rods  is  a  very  important 
matter.  They  are  frequently  connected  to 
large  copper  plates  which  are  buried  in  a 
mass  of  coke  at  a  depth  which  is  below 
the  permanent  water  level  of  the  earth.* 

The  metal  cage  or  rods  should  have  a 
number  of  high  points  extending  above  the 
level  of  the  building;  and  should  have  few 
joints  and  no  sharp  bends.  Our  commer- 
cial currents  will  follow  good  conductors 
around  any  amount  of  curving,  but  light- 


Actual  Photograph  Taken  After  a  Severe  Electric  Storm  Showing  the  Lightning's  Toll  in 
Valuable  Live-Stock.    The  Barn  Was  Unrodded,  as  May  Be  Surmised,  for  It  Is  Very 
Seldom  that  Fatalities  Occur  Where  Buildings  Are  Properly  Covered  with  First-Class 
Lightning  Rods,  Thoroly  Grounded  in  Damp  or  Wet  Earth. 


WHAT  TO  DO  IN  A  THUNDER 
STORM. 

If  you  are  out  of  doors  in  a  very  severe 
electrical  storm,  it  is  well  to  observe  the 
following  rules  for  your  own  protection. 

1.  Keep  away  from  wire  fences.  They 
may  carry  a  dangerous  electrical  charge 
long  distances.  Cattle  in  pastures  are 
frequently  killed  from  the  neglect  of 
farmers  to  ground  the  wire  of  the  fence. 

2.  Keep  away  from  hedges,  ponds,  and 
streams. 

3.  Keep  away  from  isolated  trees.  Oak 
trees  are  frequently  struck;  beech  are 
seldom  struck.  It  is  safe  in  a  dense 
forest. 

4.  Keep  away  from  herds  of  cattle  and 
crowds  of  people. 

5.  Do  not  hold  an  umbrella  over  you. 

6.  It  is  safer  to  sit  or  lie  down  in  an 
open  field  than  to  stand. 

7.  Drivers  should  dismount  and  not 
stay  close  to  their  horses. 

8.  Do  not  work  with  any  large  metal 
tool  or  implement. 

If  you  are  indoors: — 

1.  Keep  away  from  the  stove  and 
chimney.  The  hot  gases  from  the  chim- 
ney may  conduct  the  lightning  to  and 
down  the  chimney. 

2.  Do  not  take  a  position  between  two 
bodies  of  metal  as  the  stove  and  water 
pipe,  for  example.  An  exception  to  being 
near  metals  is  the  case  of  an  iron  bed. 
One  of  the  safest  places  is  on  a  mattress 
in  an  iron  bed,  provided  you  do  not  touch 
the  metal.  The  metal  surrounding  you 
makes  a  safe  cage  which  will  prevent  the 
lightning  from  reaching  a  person  inside. 

3.  Do  not  stand  on  a  wet  floor  nor  d.-aw 
water  from  the  well  or  faucet. 

4.  Do  not  stand  directly  under  a  chan- 
delier, near  a  radiator,  nor  on  a  register. 

5.  Do  not  use  the  telephone. 


*Specifications  for  installing  lightning  rods  are 
given  in  Technologic  Paper  No.  56,  Bureau  Stand- 
ards, at  35c,  procurable  from  Government  Printing 
Office,  Wash.,  D.  C. 


ning  will  often  jump  off  from  a  good  con- 
ductor at  a  sharp  bend,  even  tho  it  must 
pass  thru  a  poorer  conductor. 

There  are  two  ways  in  which  lightning 
rods  protect  a  house.  First,  they  serve  as 
conductors  carrying  the  discharge  harm- 
lessly ;  second,  they  tend  to  discharge  the 
earth  slowly.  Often  such  an  amount  of 
electricity  escapes  by  this  slow  discharge 
that  a  lightning  stroke  is  prevented,  or  if  not 
prevented  it  is  less  severe.  Occasionally  a 
rodded  house  is  struck, 
but  the  damage  is  much 
less  than  if  the  house 
had  been  unrodded.  The 
idea  that  lightning  rods 
draw  lightning,  and  are 
a  source  of  danger,  is 
unfounded  even  if  the 
rods  are  poorly  ground- 
ed. The  majority  of 
fires  resulting  when 
lightning  strikes  rodded 
buildings  occur  when 
masses  of  metal,  gut- 
ters, pipes,  etc.,  are  not 
connected  to  the  light- 
ning rods  or  are  not 
grounded. 

Sir  Oliver  Lodge 
classifies  lightning  as 
"A"  flashes  and  "B" 
flashes.  The  A  flashes 
are  less  sudden  and  vio- 
lent, and  are  what  the 
Germans  term  cold 
lightning.  Lightning 
rods  are  effective  pro- 
tection against  them. 
The  B  flashes  are  sud- 
den and  violent,  and  are 
what  the  Teutons  term 
burning  lightning. 
Lightning  rods  will  not 
always  safeguard 
against  these  flashes. 
Both  the  A  and  B 
flashes  are  fatal  to 
man.  Ball  lightning  is 
produced  when  the  B  flashes  strike  the 
ground.  The  A  flashes  are  the  more  com- 
mon. When  a  storm  is  at  such  a  distance 
that  flashes  of  light  are  seen  but  no  thun- 
der is  heard,  the  flashes  are  termed  heat 
lightning.  The  thunder  may  be  refracted 
above  the  head  of  the  observer  or  it  may 
be  at  such  a  distance  that  its  intensity  is 
so  decreased  as  to  become  inaudible. 

If  a  person  forms  a  part  of  the  conduct- 
ing path  of  the  discharge,  he  is  likely  to 
suffer  and  yet  the  stroke  may  not  prove 
fatal. 

The  heart  is  the  chief  danger  spot.  It 
is  not  the  voltage  but  the  current  which 
passes  thru  the  heart  which  is  the  important 
thing.  Tho  with  a  given  body  resistance, 
an  increased  voltage  causes  an  increased 
current  to  pass.  It  has  never  been  deter- 
mined with  accuracy  just  howr  much  cur- 
rent can  pass  thru  the  human  body  with 
safety.  It  doubtless  varies  with  individuals. 
High  voltage  causes  paralysis  which  may 
stop  breathing,  and  even  the  heart's  action. 
First  aid  in  lightning  stroke  should  be  arti- 
ficial respiration,  the  same  as  is  used  to 
restore  a  drowning  person. 

No  danger  results  when  a  comparatively 
large  current  flows  thru  the  lower  trunk 
alone,  but  as  low  a  pressure  as  65  volts 
has  been  known  to  prove  fatal,  when  it 
past  thru  the  thorax. 

The  resistance  of  the  skin  varies  with 
its  dryness,  moisture,  greasiness,  and  by  the 
area  which  is  in  contact  with  an  electric 
conductor.  A  bare  wire  carrying  our  ordi- 
nary lighting  current  at  110  volts  or  220 
volts  pressure  may  be  handled  safely  if  the 
skin  which  the  wire  touches  is  dry  or  if  the 
person's  boots  by  which  the  current  leaves 
(Continued  on  page  212) 


176 


THE  ELECTRICAL  EXPERIMENTER 


July,  1917 


The  Science  of  Sound 


SOUND  is  that  mysterious  phenomenon 
of  nature  by  which  we  are  able  to 
communicate  intelligence  to  one  an- 
other, and  by  which  it  becomes  pos- 
sible to  accomplish  many  industrial 
and  scientific  wonders,  and  according  to 
Professor  Dayton  C.  Miller,  of  the  Case 
School  of  Applied  Science,  Cleveland,  O., 
we  may  define  sound  as  the  sensation  re- 


are  enabled  to  present  thru  the  courtesy  of 
Prof.  Miller,  who  is  considered  a  very 
high  authority  on  the  science  and  physics 
of  sound,  illustrate  but  a  few  of  the  hun- 
dreds of  extremely  interesting  demonstra- 
tions and  peculiar  devices  which  have  been 
worked  out  in  the  physical  study  of  sound. 

One.  of  the  accompanying  illustrations 
shows  how  laboratory  apparatus  may  be 


The  tuning  fork  may  be  adjusted  for  dif- 
ferent frequencies  when  desired  and  in  gen- 
eral corresponds  to  the  usual  musical  tuning 
fork,  except  that  a  small  electro-magnet 
is  placed  between  the  two  prongs.  When  a 
battery  current  is  past  thru  this  electro- 
magnet, it  attracts  the  opposite  leg  and  sets 
the  fork  vibrating,  the  battery  current  be- 
ing interrupted  at  every  swing  of  the  tun- 


Prof.  W.  C.  Sabine  of  Harvard  University  Has  Made  the  Accompanying  Remarkable  Photographs  Showing  First — the  Start  of  a  Sound  Wave 
Into  an  Auditorium,  (Left).     At  Center,  the  Sound  Wave  Photograp h<=>d  3-100ths  Second  After  Its  Production  on  Stage.     Right — Echoes 
in  a  Theater  Developed  from  a  Single  Sound  Impulse  in  14-100ths  Second,  Resulting  in  What  We  Call  "Reverberation." 


suiting  from  the  action  of  an  external 
stimulus  on  the  sensitive  nerve  apparatus  of 
the  ear.  In  other  words,  it  is  a  species  of 
reaction  to  this  external  stimulus,  excitable 
only  thru  the  ear,  and  dis- 
tinct from  any  other  sensa- 
tion. Atmospheric  vibration 
is  the  normal  and  usual 
means  of  excitement  for  the 
ear.  This  vibration  originat- 
ing in  a  source  known  as  the 
sounding  body,  which  is  it- 
self always  in  vibration.  For 
instance,  the  source  of  the 
sound  may  be  constructed  es- 
pecially to  produce  a  certain 
quality  as  in  a  stringed  in- 
strument, whether  the  string 
is  plucked  or  bowed,  and  its 
consequent  vibration  trans- 
ferred to  the  wooden  or 
other  sound-board  and  which 
in  turn  impresses  the  motion 
upon  a  larger  mass  of  air. 

The  word  sound  is  used 
by  the  scientist  to  designate 
the  vibrations  of  the  sound- 
ing body  itself  or  those 
which  are  set  up  by  the  sounding  body 
in  the  air  or  other  medium,  and  which 
are  capable  of  directly  affecting  the  ear, 
even  tho  there  is  no  ear  to  hear;  the  sound 
going  forth  just  the  same. 

The  accompanying  illustrations  which  we 


set  up  so  as  to  cause  a  single  taut  string 
to  vibrate  in  a  single  loop.  In  taking  the 
photograph  of  the  vibrating  string,  a  black 
background  was  provided,  so  as  to  show 


Interesting  Vi 
a  Simple  Ton 


ew  of  a  String  Vibrating  in  a  Single  Loop,  Co 
e  of  a  Fundamental  Only.     An   Electrically  Vi 
Fork  Is  Used  in  This  Experiment. 

the  loop  of  vibration  more  clearly.  This 
single  loop  corresponds  to  a  simple  tone 
consisting  of  a  fundamental  only.  The 
string  is  secured  at  one  end  to  a  stationary 
support,  and  at  the  other  to  one  prong  of  a 
special    electrically-operated    tuning  fork. 


ing  fork  limbs  by  virtue  of  a  platinum  con- 
tact mounted  on  the  vibrating  fork.  The 
string  may  consist  of  a  silk  cord. 
By  simply  changing  the  tension  of  the 
string  so  arranged,  it  can 
be  made  to  vibrate  in  va- 
rious   sub-divisions  corre- 
sponding  to    its  harmonic 
over-tones.     For  instance, 
it  may  be  caused  to  show 
two-loop,    three-loop  and 
five-loop  formations,  repre- 
senting respectively  the  first, 
second    and    fourth  over- 
tones. 

One  of  the  most  remark- 
able sound  analyzing  instru- 
ments is  Professor  Miller's 
Phonodeik.  This  instru- 
ment has  been  made  in  sev- 
A  J*L  eral  different  forms  for  es- 

fjiAfe  pecially  analyzing  and 
'Mmfa-JSk  studying  the  various  funda- 
sP^^*9(  mental  tones  and  harmonics 
of  musical  and  other  sounds 
in  the  laboratory,  but  the  one 
here  shown  is  probably  of 
the  greatest  interest  to  the 
layman.  By  means  of  the 
projection  type  of  phonodeik  (here  il- 
lustrated), Prof.  Miller  was  enabled 
to  present  some  very  startling  effects 
in  his  recent  lectures  in  New_  York 
City  before  the  American  Association  for 
the  Advancement  of  Science.    When  the 


rresponding  to 
brated  Tuning 


Many  Valuable  Studies  of  Sound  Waves  Can  Be  Made  by  Means  of  "Sand   Figures."     The  Sand 

Be  Vibrated  at  Any  Desired  Frequency  or  Note. 


Placed 


Diafram  Which  Can 


July,  1917 


THE  ELECTRICAL  EXPERIMENTER 


word  "War"  for  instance  was  pronounced 
into  the  horn  of  the  phonodeik,  its  tiny  re- 
volving mirror  caused  a  narrow  beam  of 
light  to  dance  wildly  on  the  stage  screen, 
but  when  the  word  "Peace"  was  spoken  into 
the  instrument,  the  light  beam  smoothed 
out  remarkably,  exercising  a  wonderful  and 
truly  remarkable  psychological  effect  on  the 
audience. 

The  operation  of  the  phonodeik,  which 
is  the  result  of  many  years'  study,  is  based 
upon  the  use  of  a  vibrating  diafram,  which 
is  placed  at  the  base  of  the  horn  shown. 
The  movements  of  the  diafram  due  to 
vocal  or  musical  sounds  projected  into  the 
horn  cause  it,  with  its  vibrating  mirror, 
to  project  a  tiny  beam  of  light,  which  fall- 
ing upon  a  motor-driven  revolving  mirror, 
is  thrown  on  to  the  white  screen  on 
the  stage  in  the  form  of  a  long  wave.  The 
movements  of  the  diafram  are  magnified 
forty  thousand  times  or  even  more,  pro- 
ducing a  "light"  sound  wave  on  the  screen 
which  may  measure  ten  feet  in  width  and 
even  forty  feet  in  length,  suitable  for  a 
practical  demonstration  of  the  physics  of 
sound  to  an  audience  of  any  magnitude. 

The  projection  phonodeik  possesses  many 


rarefactions  which  are  projected  thru 
space  with  a  velocity  of  1,132  feet  per  sec- 
ond (at  70°  Fahrenheit),  and  for  the  tone 
"middle  C,"'  the  distance  from  one  com- 
pression to  the  next  is  about  four  feet. 
It  would  prove  very  desirable  indeed  to 
be  able  to  actually  photograph  sound  waves 
in  air,  but  no  practical  means  have  as  yet 
been  perfected  for  photographing  waves 
of  this  size.  The  accompanying  photo- 
graphs of  a  cross-sectional  model  of  a 
theater  showing  the  progress  of  a  sound 
wave  from  the  stage  is  due  to  the  re- 
searches of  Prof.  W.  C.  Sabine,  of  Har- 
vard University.  Photographs  such  as  these, 
showing  the  sound  wave  at  any  instant, 
are  taken  by  instantaneous  exposures  and 
are  obtained  by  the  snapping  sound  pro- 
duced by  the  electric  spark  discharge 
from  a  Leyden  jar.  The  sound  thus  given 
off  by  a  Leyden  jar  discharge  consists  of 
a  single  wave  containing  one  condensation 
and  one  rarefaction,  the  wave  length  of 
which  may  be  1/16  inch  or  less,  and  the 
sound  is  relatively  a  loud  one.  Now  if, 
while  such  a  sound  wave  is  past  over  a 
photograph  plate  in  the  dark,  the  wave  is 
instantaneously  illuminated  by  a  single  dis- 


The  Marvelous  "Phonodeik"  Devised  by  Prof.  Dayton  C.  Miller,  Which,  by  Extremely  Delicate 
Electro- Mechanical  Attachments,  Permits  a  Lecturer  to  Project  on  a  Screen  the  Undulations 
of  the  Speaking   Voice,   Magnified  40,000  Times!     Truly   a   Scientific    Masterpiece   and  An 
Invention  of  Far-Reaching  Importance  and  Application. 


remarkable  qualities,  among  which  we  find 
that,  if  the  revolving  mirror  is  kept  sta- 
tionary the  spot  of  light  on  the  screen 
moves  in  a  vertical  line  as  the  diafram 
vibrates ;  tho  these  movements  are  super- 
posed, their  extreme  complexity  is  shown 
since  the  turning  points  are  made  evident 
by  bright  spots  of  light.  If  we  turn  the 
mirror  slowly  by  hand,  then  the  production 
of  the  harmonic  curve  by  the  combination 
of  vibratory  and  translator)-  motions  is 
demonstrated.  By  the  aid  of  a  simple 
tuning  fork,  the  simplicity  and  wonders 
of  the  sine  curve  are  exhibited  grafically. 
By  using  two  tuning  forks,  it  becomes  pos- 
sible to  demonstrate  before  a  large  audi- 
ence, the  combination  of  sine  curve  waves. 
Also  the  relations  of  loudness  to  ampli- 
tude, and  of  pitch  to  wave  length  may 
be  fully  demonstrated.  As  the  sound 
changes  at  the  phonodeik  apparatus,  the 
light  wave  follows  in  consequence,  and  the 
projected  image  on  the  screen  undulates 
rythmically,  and  in  a  most  remarkable  man- 
ner. 

Three  interesting  illustrations  are  pre- 
sented herewith  which  show  the  progress 
of  a  sound  wave  in  a  theater ;  the  wave 
gradually  swelling  out  into  the  auditorium 
until  the  main  wave  has  reached  the  back 
of  the  gallery  and  been  reflected. 

Sound  waves,  according  to  Prof.  Miller, 
consist    of    alternate    condensations  and 


tant  electric  spark,  then  the  light  from  the 
spark  will  be  reacted  by  the  sound  wave 
which  will  then  act  as  a  lens  and  register 
itself  on  the  plate.  The  accompanying 
photographs,  due  to  Professor  Sabine,  show 
some  of  the  work  carried  out  by  him  in 
studying  the  problem  of  auditorium  acous- 
tics. 

To  make  such  sound  wave  photographs, 
a  small  cross-sectional  model  of'  the  audi- 
torium is  first  made.  The  photograph  plate 
is  placed  behind  the  model ;  the  sound  is 
produced  on  the  stage  at  the  right,  and 
the  resulting  wave  is  propagated  out  into  the 
auditorium  .with  a  velocity  of  1,132  feet 
per  second.  The  second  view  shows  the 
period  just  before  the  main  sound  wave 
reaches  the  balcony,  and  the  final  photo 
shows  the  wave  14/100ths  second  after  the 
production  of  the  original  sound  on  the 
stage,  when  the  main  wave  has  reached  the 
back  of  the  gallery.  It  will  be  noted  that 
a  large  number  of  echo  waves  appear,  and 
which  seem  to  come  from  many  different 
directions,  but  which  are  actually  generated 
by  the  one  original  impulse.  The  multiple 
echoes  continue  to  develop  with  ever  in- 
creasing confusion  until  finally  the  sound 
is  diffused  thruout  the  auditorium,  when 
we  have  the  condition  known  as  reverber- 
ation. This  explains  the  effect  occurring 
in  a  theater,  when  we  hear  anyone  say 
that  the  singer  has  such  a  powerful  voice 


that  the  music  rever- 
berates thruout  the 
auditorium. 

A  great  deal  of  study 
can  be  and  has  been 
carried  out  in  the  realm 
of  sound  studies  by 
means  of  sand  figures. 
These  are  known  as 
Chladnis'  figures,  and 
one  of  the  accompany- 
ing illustrations  shows 
three  interesting  forms 
produced  by  certain 
sounds.  A  large  num- 
ber of  patterns  can  be 
formed  by  the  various 
sounds,  and  which  pat- 
terns or  figures  are  al- 
ways the  same  for  the 
same  note. 

As  an  example  of 
what  has  been  accom- 
plished in  this  direc- 
tion, it  may  be  of  in- 
terest to  state  that,  with 
a  diafram  of  glass  held 
in  circular  rings  and 
placed  horizontally,  the 
vibrator  being  attached 
to  the  under  side  ;  when 
sand  w  a  s  sprinkled 
over  the  diafram, 
figures  were  obtained 
as  the  diafram  was 
made  to  respond  in  suc- 
cession to  each  one  of 
eighty  pipes  corre- 
sponding to  frequen- 
cies from  129  to  12,400. 
The  characteristic  no- 
dal lines  produced  for 
each  frequency  were 
then  photographed. 

Our  long,  narrow  il- 
lustration carrying  the 
continuous  undulating 
sound  wave  as  shown 
at  right  is  one  of  the 
most  remarkable  rec- 
ords of  vocal  music 
ever  obtained.  It  was 
made  in  Professor 
Miller's  laboratory,  and 
is  part  of  a  record  of 
world-famous  opera 
singers  singing  the  sex- 
tette from  "Lucia  di 
Lammermoor."  The 
white  dots  along  the 
edge  of  the  record 
represent  the  time 
periods  1/100  of  a 
second  apart.  The  orig- 
inal photographic  rec- 
ord of  this  bit  of  opera 
is  nearly  four  times  as 
long  as  the  one  here  re- 
produced. The  particu- 
lar section  of  the  rec- 
ord illustrated  shows 
the  voice  undulations 
and  variations  of  Mme. 
Tetrazzini  and  Signer 
Amato,  i.e.,  soprano 
and  baritone  voices 
singing  softly.  This 
particular  section  of  the 
voice  record  has  a  dur- 
ation of  .80  second,  and 
is  for  a  single  note. 


The  Voice  Record  at  the 
Right  Shows  the  Undu- 
lations Occurring  When 
Tetrazzini  and  Amato 
(Soprano,  and  Baritone) 
Warble  a  Note  from 
"Lucia  di  Lammer- 
moor.'' Each  Dot  is 
1-100th  Second  Apart; 
the  Time  Period  of  the 
Record  Shown  Is  .80 
Second  and  Is  for  a 
"Single  Note." 


178 


THE  ELECTRICAL  EXPERIMENTER 


July,  1917 


TELEPHONE  AND  RADIO  IN  WAR- 
TIME FRANCE. 

The  French  army  lias  perhaps  made 
greater  use  of  all  electrical  means  of  com- 
municating   intelligence    than    any  other 


many  thousands  can  he  found  just  back 
of  the  battle  lines.  The  telephone,  tele- 
graph and  radio  stations  are  often  located 
in  the  basement  of  a  once  beautiful  cha- 
teau or  church. 


dreds,     even     thousands     of     men.  He 

must     not     make     a     mistake     and  his 

instruments  must  always  work- — so  long 
as  his  antenna  stays  up. 


Here  We  See  Two  Interesting  French  War 
Pictures.  At  Left — Telephone  Switchboard 
at  Headquarters.  Right — Radio  Station 
Near  the  Battle  Front  "Somewhere  in 
France." 


Of 


military  organization  of  the  present  time. 
(The  illustrations  herewith  show  a  central 
telephone  switchboard  at  army  headquar- 
ters and  a  typical  radio  station,  of  which 


TORPEDO  NOW  USED  AS  LAMP- 
POST. 

The  accompanying  illustration  shows  an 
odd  electric  lamp-post  in  use  at  Newport, 
R.  I.  It  is  formed  of  a  one-time  danger- 
ous torpedo,  which  was  captured  in  the 
Spanish-American  War.    The  torpedo  has 


,1    M^ORO  WIN  OCR 

—  CORD  TO  TELEPHONE  HOOK 


Photo  Copyright  by  Presa  Illustrating  Service. 

A  One-Time  Formidable  Torpedo,  Captured 
in  the  Spanish-American  War,   Now  Serves 
as  a  Lamp-Post  at  Newport,  R.  I. 


The  central  telephone  switchboard  shows 
how  cable  lines  are  brought  in  from  every 
important  army  division.  By  means  of 
the  flexible  cord  and  attachment  plug  con- 
nected to  the  wall  telephone  instrument  seen 
in  the  picture,  an  officer  of  the  command- 
ing staff  may  instantly  ring  up  any  divi- 
sion commander  and  transmit  orders  or 
receive  a  special  report  as  to  the  progress 
of  a  battle  at  any  certain  part  of  the  front. 

The  head  telephone  set  lying  on  the 
table  is  used  to 
listen  in  secretly 
into  any  line  run- 
ning from  the 
trenches  to  head- 
quarters. Thus 
the  officer  in 
charge  may  know 
at  once  if  unau- 
thorized talk  is 
going  on. 

But  to  the  radio 
operator  comes  a 
full  share  of  mys- 
tery, romance  and 
action.  He  sit:, 
with  his  head  re- 
ceivers clamped 
tight  against  his 
ears  while  from 
out  of  the  bound- 
less ether  there 
comes  the  news 
of  victory  or  de- 
feat— the  call  for 

reinforcements — messages  of  every  descrip- 
tion and  from  many  points  along  the  battle 
front.  Needless  to  say  the  military  radio 
operator  holds  a  most  important  position — 
an  importance  which  the  peace-time 
operator  never  even  dreams  about.  In 
his  hands  there  may  lie  the  differ- 
ence    between    life    and    death    for  hun- 

been  securely  anchored  in  the  ground  and 
the  electric  feed  wires,  supplying  the  lamps 
at  the  top  with  current  pass  thru  the  hol- 
low shell.  The  relative  size  of  the  torpedo 
may  be  judged  by  comparing  it  with  the 
marine  standing  beside  it.  Rather  an  ex- 
pensive lamp-post,  as  lamp-posts  go,  this 
particular  one  having  cost  about  $7,000 
originally  when  the  Spanish  torpedo  factory 
turned  it  out. 


NEW  INVENTION  'PHONES 
POLICE— "THIEF'S  HERE." 

Burglar  detection  is  made  a  matter 
certainty  and  simplicity  by  means  of  a 
device  invented  by  Lee  A.  Collins,  of  Louis- 
ville, Kentucky,  Patents  are  pending  on 
the  invention. 

With  the  installation  of  the  alarm,  a 
burglar  in  forcing  or  gaining  an  entrance 
sets  in  motion  the  mechanical  device,  which 
then  summons  the  police,  giving  them  the 
name  and  address  of  the  person  whose 
home  or  office  is  being  entered. 

Another  type  of  the  device  does  not 
operate  with  a  phonograph  attachment,  but 
instead  has  a  buzzer  which  warns  central, 
who  in  turn  reports  the  matter  to  the  po- 
lice. Anotlier  type  of  the  invention  has 
a  bell  which  is  controlled  by  thermostats, 
and  gives  fire  alarms  as  well  as  burglar 
alarms. 

The  alarm  does  not  cease  if  a  window 
or  door  is  closed  immediately  after  be- 
ing opened,  but  continues  at  work  until 
the  connection  is  cut  off.  The  device  is 
simple  in  construction,  and  can  be  attached 
to  any  telephone.  A  special  attachment 
makes  it  possible  for  bank  or  express  com- 
pany cashiers  to  start  the  mechanism  by 
pressure  of  the  foot  or  knee  in  the  event 
an.  attempt  is  made  at  a  hold-up.  Two 
dry  cell  batteries  operate  the  entire  sys- 
tem. If  the  bank  cashier  is  held  up,  for 
instance,  he  simply  obeys  orders  and  throws 
up  both  hands  if  he  deems  it  best,  but 
his  foot  is.  busy  meanwhile,  and  when  the 
foot  operated  trip-switch  closes,  the  Col- 
lins automatic  telephone  alarm  immedi- 
ately gets  busy.  It  raises  the  telephone 
hook  (in  another  room,  so  the  thief  will 


CONCIAIEO  HIRES  TO  ANOTHER  ROOM 


When  the  Bank  Robber  Appears  Now,  the  Cashier  Simply  Presses  a 
Button  with  His  Foot.    This  Causes  a  Special  Device  in  Another  Room 
to   Lift  the  Telephone   Hook  and   Start  a   Phonograph   Which  Gives 
Central  the  Call  for  Police. 

not  become  desperate)  and  simultaneously 
starts  a  small  phonograph  located  near  the 
telephone.  It  carries  a  special  record,  an- 
nouncing the  bank's  name,  the  location 
and  the  news  that  the  "thief's  here !"  It 
repeats  the  message  over  and  over  again, 
notifying  Central,  who  at  once  informs 
police  headquarters. 


A  trap  drummer  has  discovereo.  that  elec- 
tric lights  installed  inside  his  drums  keep 
the  moisture  out  and  makes  the  drumheads 
tight. 


The  new  battleship  Tennessee  will  use 
27,500  electrical  horsepower,  enough  power 
to  furnish  heat,  light  and  power  for  a  city 
of  100,000  inhabitants. 


July,  1917 


THE   ELECTRICAL  EXPERIMENTER 


1  79 


I  Speeding  Up  Vote  of  Congress  by  Electricity 


Instead  of  Wasting  an  Hour  and  a  Half  in  Which  to  "Call  the  Roll"  Alone  in  the  House  of  Representatives  at  Washington,  a  Newly  Pro- 
posed Electric  Voting  System  Will  Cut  the  Time  Down  to  a  Few  Minutes,  Resulting  in  a  Saving  of  Thousands  of  Dollars  Annually. 


HAVE  you  ever  been  present  at  the  roll 
call  of  the  U.  S.  Senate  or  House  of 
Representatives?  If  you  haven't  then 
it  is  perhaps  difficult  to  realize  how  much 
valuable  time  is  lost  by  calling  the  roll  of 
such  august  bodies.  Mr.  Wilfred  Lewis  was 
quite  surprised  not  long  ago,  as  perhaps 
sQme  of  our  readers  will  be  now,  to  learn 
that  it  takes  generally  no  less  than  an  hour 
and  a  half  to  get  a  vote  of  the  House  of 
Representatives,  using  the  tedious  and 
antiquated  process  of  calling  the  roll.  In 
fact,  a  favorite  form  of  filibustering  in 
the  House  is  to  keep  demanding  roll  calls 
on  every  question  that  comes  up,  some  of 
them  introduced  for  the  purpose.  It  oc- 
curred to  Mr.  Lewis  that  in  this  electrical 
age  some  more  efficient  method  might  be 
adopted,  and  he  proposes  a  far  more  ac- 
curate one,  which  he  thinks  might  accom- 
plish the  same  result  in  half  a  minute  or 
less.  Such  a  device  has  been  in  use  in  the 
Russian  Duma  for  years,  and  presumably 


there  is  some  reason  why  other  legislative 
bodies  have  not  adopted  it. 

Mr.  Lewis  goes  on  to  say :  "It  occurred 
to  me  while  listening  to  the  debates  in  the 
House,  followed  by  such  interminable  roll 
calls,  that  a  vote  on  any  question  had  bet- 
ter be  'seen  than  heard,'  that  the  old  max- 
im should  not  be  applied  exclusively  to 
children.  The  talk,  of  course,  will  go  or! 
forever,  but  with  a  little  preparation  the 
vote  might  be  Hashed  instantly  on  a  screen 
back  of  the  Speaker  in  full  view  of  every 
member  and  be  photographed  by  an  oper- 
ator in  the  gallery  near  the  clock.  This 
procedure  would  require  that  every  member 
of  the  House  have  a  lock-box  in  front  of 
his  seat  which,  when  opened,  would  cause 
his  name  to  appear  in  a  certain  space  on 
the  wall  or  screen.  When  a  vote  was  called 
for,  he  would  press  a  button  showing  'Yes' 
or  'No'  opposite  his  name,  or  simply  vote 
'present'  by  doing  nothing.  The  number  or 
title  of  the  bill  would  be  displayed  at  the 
same  time ;  and  if  the  record  was  illumi- 


nated, it  could  be  quickly  photographed. 

"I  believe  the  time  will  come  when  all 
legislative  bodies  will  be  equipt  for  voting 
in  this  expeditious  way,  and  that  the  same 
method  will  be  adopted  by  engineering  and 
other  bodies  that  have  no  time  to  burn. 

"You  can  readily  estimate  the  cost  of 
the  voting  done  by  500  or  1,000  high-priced 
men  day  after  day  and  year  after  year 
in  the  present  absurd  way.  The  cost  of 
installing  effective  voting  machinery  in  Con- 
gress might  be  considerable,  but  it  would 
soon  be  saved  at  the  rate  of  perhaps  $2,000 
an  hour  in  the  cost  of  legislation  ;  and  more 
time  could  also  be  given  to  the  consider- 
ation of  the  bills  presented." 

The  illustration  we  present  herewith 
shows  President  Wilson  addressing  a  joint 
session  of  Congress  in  the  hall  of  the  House 
of  Representatives,  with  an  automatic  elec- 
tric vote-recording  bulletin,  as  suggested 
by  Mr.  Lewis,  mounted  on  the  wall  above 
the  Speaker's  chair. 


The  U.  S.  Signal  Corps  Wants  You ! 


FOR  the  information  of  all  applicants  in 
Signal  Enlisted  Reserve  Corps,  we 
give  below  the  general  plan  of  the 
training  and  preparation  the  new  units  of 
Signal  Reserve  Corps  are  to  receive  before 
they  are  fitted  for  work  in  connection  with 
other  arms  of  the  service. 

"In  the  first  place,"  says  Major  Carl  F. 
Hartmann,  of  the  New  York  Headquarters, 
"we  have  attempted  to  enlist  only  such  men 
as  are  technically  qualified  to  carry  on  the 
usual  functions  of  the  Signal  Corps  without 
additional  technical  training.  We  expect  to 
give  them  additional  training  concerning  the 
use  and  operation  of  equipment  directly 
pertaining  to  Signal  Corps  Battalions,  also 
an  intensive  course  of  military  training 
which  will  make  our  organization  an  effi- 
cient military  unit  for  active  service. 

"Our  advice  to  men  who  enlist  is  to  con- 
tinue their  ordinary  pursuits  until  they  re- 
ceive the  call  from  the  President,  then  report 
immediately  to  the  place  designated.  In  the 
meantime  it  will  be  well  for  them  to  notify 
their  employers  that  they  will  be  subject  to 
the  call  of  the  President,  and  must  leave 
his  employ  when  they  are  notified,  other- 
wise their  status  with  him  will  be  the  same 
as  it  has  been  formerly. 


"Equipment  for  all  men  enlisted,  such  as 
uniforms,  bedding,  messing  utensils,  etc., 
will  be  available  for  issue  at  the  camps  of 
instruction.  Each  man  enlisted  will  from 
the  time  he  reports  receive  the  same  pay 
and  allowances  as  the  corresponding  grade 
in  the  regular  army.  They  are  also  entitled 
to  transportation  in  kind  and  commutation 
of  rations  at  50  cents  per  meal  for  the  time 
of  actual  travel  from  their  homes  to  places 
to  which  ordered  for  active  service.  If 
transportation  in  kind  is  not  furnished  from 
their  homes  to  place  ordered  for  active 
service,  they  are  entitled  to  reimbursement 
for  the  actual  necessary  cost  of  such  trans- 
portation. 

"The  term  of  enlistment  is  for  four  years. 
However,  the  President  of  the  United  States 
has  stated  that  the  Reserve  Corps  will  be 
held  in  active  service  only  during  the  period 
of  the  emergency. 

"It  is  proposed,  in  the  Eastern  Depart- 
ment, to  organize  ten  (10)  Field  Battalions, 
Signal  Reserve  Corps,  and  the  proper  mate- 
rial for  these  organizations  appears  to  be 
scarce. 

"These  Battalions  will  require  men  who 
have  technical  ability.  Most  of  all,  Ave 
want  operators,  both  Morse  and  Continental. 


In  addition  to  operators,  men  must  be  ob- 
tained who  have  had  technical  training,  or 
who  have  had  an  education  which  will 
enable  them  to  quickly  grasp  the  mechanical 
and  electrical  work  incident  to  the  opera- 
tions of  a  Field  Battalion  Signal  Corps  in 
active  service.  The  men  must,  in  addition 
to  above  qualifications,  be  strong  and  ath- 
letic, and  preferably  horsemen. 

"A  Field  Battalion  of  Signal  Corps  is  an 
organization  for  which  college  and  techni- 
cal men  are  especially  adapted.  The  work  is 
active  and  interesting.  It  is  necessary 
everywhere,  on  the  battlefield  as  well  as  on 
the  lines  of  communication  to  the  bases. 
The  Signal  Corps'  drills  involve  the  prin- 
ciples of  nearly  all  the  other  branches  of  the 
Army,  in  addition  to  the  interesting  ap- 
paratus necessary  for  the  transmission  of 
information.  We  are  prepared  to  follow 
the  cavalry  at  whatever  gait  they  desire  to 
take.  We  work  in  conjunction  with  the 
artillery,  and  the  infantry  rely  on  us  for 
their  information.  The  Signal  Corps  has 
been  termed  the  "Nerves  of  the  Army,"  and 
is  a  very  necessary  branch  of  the  service. 
At  this  time,  due  to  the  unusual  expansion 
of  the  Army,  promotion  should  be  rapid 
(Continued  on  page  214) 


180 


THE  ELECTRICAL  EXPERIMENTER 


July,  1917 


"Ham"  Jones — Scientist 

By  HARLAN  A.  EVELETH 


HENRY  ALFONSO  MARMA- 
DUKE  JONES,  alias  "Ham" 
Jones,  was  a  youth  of  seventeen 
summers,  awkward  and  lanky, 
with  auburn  hair  and  freckles, 
and  blue  eyes  which  imbibed  the  beauties 
of  nature — several  sat  near  him  in  "Latin 
1" — thru  the  lenses  of  omnipresent,  iron- 
rimmed  spectacles.  "Ham"  was  some  boy. 
He  had  attained  a  wide  reputation  among 
his  fellow  students  as  a  wizard  of  wire- 


Come  right  in  and  make  yourself  at  home." 
And  with  that  he  gave  me  the  "glad  hand" 
and  a  pat  on  the  shoulder. 

"The  pleasure's  all  mine!"  I  replied;  I, 
alias  "Spin"  (short  for  "Spindle")  being 
modeled  somewhat  along  the  graceful  lines 
of  a  Geissler  tube. 

"Come  right  up  stairs,"  chirped  "Ham," 
so  I  trailed  along  behind  him,  up  two  flights 
of  stairs  to  a  hall  leading  to  the  laboratory 
in  the  attic. 


"Ham"  turned  on  a  light,  and  there- 
upon my  eyes  opened  wider  and  wider 
as  I  gazed  in  mingled  awe  and  ecstasy 
upon  the  vast  accumulation  of  multifarious 
electrical  equipment  which  adorned  the 
four  walls  and  portions  of  the  ceiling  and 
floor  of  the  laboratory;  a  bewilderment  of. 
coils  of  wire,  switches,  bells,  insulators  and 
instruments  of  every  type  and  form  imagin- 
able— and  surmounting  the  whole,  a  crudely 
lettered  sign  bearing  the  ominous  warning: 


,  .  .  .  He  Picked  Up  a  Fine  Wire  from  the  Floor,  Fastened  It  to  the  Coil  and  Prest  the  Key.  Suffering  Cats!  !  !  My  Shoes  Became 
Full  of  Carpet  Tacks  and  I   Leapt  so  High  that  My  Head  Nearly  Hit  the  Ceiling.    .    .    .    'Hen'  Got  to  Laughing  so  Hard  He  Could  Not 

Keep  His  Stick  on  the  Key." 


less  telegraphy  and  as  an  authority  on  all 
the  intricacies  of  "hook-ups"  and  electrical 
phenomena  pertaining  thereto  ;  in  fact,  the 
pages  of  his  "Caesar"  housed  innumer- 
able and  priceless  diagrams  of  diagrammatic 
data,  while  a  rear  view  of  this  assemblage 
of  students  disclosed  the  existence  of  a 
secret  service  system  of  communication 
whereby  others  who  desired  information  of 
a  technical  brand  could  obtain  the  same 
direct  from  the  hand  of  the  renowned 
scientist.  "Ham"  Jones.  Thus  it  was  with 
a  great  feeling  of  joy  and  expectation  that 
I,  a  humble  member  of  the  secret  service 
organization,  accepted  the  magnanimous  in- 
vitation of  "Ham"  to  devote  an  evening 
of  my  leisure  time  among  the  electrical 
paraphernalia  of  his  far-famed  laboratory. 

I  ascended  the  steps  of  the  front  porch 
of  "Ham's"  abode  with  faltering  steps  that 
memorable  night,  and  I  pushed  the  push 
of  the  push-button  with  the  end  of  an  ink 
eraser ;  for  I  had  heard  rumors  of  "big 
sparks"  and  unexpected  shocks,  and  rub- 
ber is  an  insulator — "Ham"  had  told  me 
so. 

"Hello !  'Spin',"  quoth  "Ham,"  as  he 
swung  the  door  open.    "Glad  to  see  you! 


"There's  my  room,  you  can  open  the 
door  and  step  right  in,"  gurgled  "Ham." 
"I  left  something  down  stairs,  I'll  be  back 
in  a  moment." 

"All  right,"  I  said,  innocently,  and  then 
grasped  the  knob  of  the  door.  I  had 
pushed  it  about  half  open  when  the  knob 
suddenly  turned  red-hot,  or  something,  and 
it  would  not  let  go  of  my  hand  for  all 
I  could  do  to  persuade  it  to.  "Ham" 
stood  on  the  stairs,  with  his  hand  beneath 
the  railing,  and  laughed  so  hard  that  he 
finally  sat  down  on  the  steps  to  keep  from 
tumbling  the  whole  length ;  thereupon  the 
knob  turned  "cool"  and  I  yanked  my  hand 
away. 

"You  big  boob !"  I  yelled,  for  I  was 
scared  and  about  ready  to  choke.  "Do 
you  want  to  kill  a  feller?" 

"Aw  forget  it.  You  have  to  get  used 
to  shocks  if  you're  going  into  the  wire- 
less business." 

"Yes — well,  will  you  let  me  try  it  on 
you  ?" 

"Perhaps,  later  on,  but  I've  got  lots  to 
show  you — and  besides,  it's  a  waste  of 
'juice.'  Come  in  and  I'll  show  you  my 
junk."    So  in  I  went. 


DANGER ! 

150,000  VOLTS 
All  Persons  Entering  This 
Laboratory  Do  So  At 
Their  Own  Risk 


"Hen,"  I  said,  in  a  plaintive  tone,  as 
if  about  to  ask  him  for  a  job.  "I  guess 
I'll  stand  over  near  the  doorway."  I  was 
careful  to  call  him  "Hen",  for  I  feared 
dire  consequences  if  I  should  offend  his 
dignity. 

"No,  you  stay  right  where  you  are," 
he  retorted.  "There  will  be  no  danger  as 
long  as  you  keep  your  hands  off  the  wires." 

"But  how  about  those  150,000  volts?" 

"Don't  you  worry  about  them.  They  are 
Tesla  coil  volts,  and  they  won't  do  more 
than  knock  you  down.  I'll  save  the  fire- 
works for  the  last,  so  that  if  you  get 
killed  you  won't  miss  any  of  the  show." 


July,  1917 


THE   ELECTRICAL  EXPERIMENTER 


181 


"Uh  huh!"  I  gasped;  then  wondered  if 
I  had  not  better  make  a  break  for  tbe 
door  while  I  had  the  chance. 

"Take  a  seat,"  said  "Ham,"  "and  I'll 
show  you  the  wireless."  So  I  gingerly 
took  a  seat,  after  first  turning  it  upside- 
down  to  discover  the  presence  of  any 
diabolical  mechanism  which  might  be  con- 
cealed in  the  cushion. 

"Now,  'Spin',"  he  said,  with  a  wave  of 
his  hand,  as  he  assumed  a  professional  atti- 
tude, "that  apparatus  over  there  on  your 
right  is  called  the  transmitting  set.  It  is 
hard  for  me  to  explain  the  function  of 
the  various  instruments  in  terms  which 
will  be  understood  by  the  layman,  so  I'll 
try  to  use  simple  language.  This  instru- 
ment here  is  called  a  transformer,  and  it 
takes  the  110  volts  and  cuts  them  up  into 
pieces  until  there  are  fifteen  thousand  volts. 
That  is  thirty  times  as  many  volts  as  run 
the  electric  cars,  so  it  is  a  very  danger- 
ous current  to  fool  with.  From  the  trans- 
former the  volts  flow  into  this  condenser, 
which  piles  'em  up  like  sardines,  until 
there  are  so  many  that  they  jump  across 
this  spark  gap.  That  coil  of  wire  is  called 
a  helix.  The  volts  get  going  around  it  so 
fast  that  some  of  them  shoot  off  into  the 
aerial,  and  from  there  into  the  ether.  That's 
about  all  there  is  to  it.  The  code  is  made 
by  punching  this  key." 

"That's  a  pretty  complicated  affair,  all 
right,"  I  ventured  to  say,  "but  there's  one 
thing  I  don't  understand.  What  do  you 
mean  by  saying  the  volts  go  into  the  ether? 
I  took  ether  when  I  had  my  arm  broken, 
but  I  don't  see  what  it  has  to  do  with 
wireless." 

"Haw !  Haw  !  The  wireless  ether  is  not 
a  liquid,  it's  a  substance,  er  'incon- 
ceivably attenuated  which  is  supposed  to  be 
coextensive  with  infinite  space.'  That  is 
the  only  way  I  can  describe  it.  I  don't 
know  much  about  it  myself.  However, 
these  instruments  over  here  are  for  re- 
ceiving. The  messages  come  down  the 
aerial,  and  then  pass  thru  those  tuning 
coils,  the  receivers  and  the  detector.  The 
detector  lowers  the  rate  of  vibration  of 
the  incoming  current  so  that  you  can  hear 
the  signals,  while  the  tuner  regulates  the 
wave-length." 

"I  think  I  understand,  but  can  I  hear 
a  message?" 

"Sure  thing!  I've  got  two,  good  (get 
that),  one-hundred-ohm  receivers  and 
we'll  have  one  apiece." 

We  clamped  the  receivers  on  our  head, 
and  "Hen"  monkeyed  with  the  switches  and 
the  detector  and  slid  the  contacts  up  and 
down  the  timing  coil  as  if  he  was  sawing 
wood,  but  the  only  thing  we  heard  was 
the  test  buzzer. 

"There  must  be  a  loose  connection  some- 
where," explained  "Hen",  as  he  made  a 
minute  examination  of  the  wiring.  Finally 
we  heard  a  series  of  loud  buzzes  which 
suddenly  broke  into  a  long  dash.  "Hen" 
Avorked  the  tuner  for  all  he  was  worth, 
but  could  not  tune  the'  station  out. 

"There's  no  use  trying,  it's  another  one 
of  those  Hams  who  sits  on  his  key  for  the 
pleasure  of  hearing  his  spark.  Those  fel- 
lows make  me  sick ;  they  have  a  habit  of 

doing  it  just  as  I  start  to  listen  to  " 

Just  then  "Hen"  lifted  his  elbow  and  the 
noise  stopt.  He  didn't  say  a  word;  just 
looked  a  bit  foolish  and  sawed  his  tuner 
harder  than  ever.  Finally  he  jumped  up, 
stuck  his  head  and  arms  out  of  the  win- 
dow and  did  something  which  suddenly 
made  the  buzzes  come  in  at  a  great  rate. 

"I  guess  that's  one  on  me,"  said  "Hen." 
"I  forgot  to  open  the  ground  switch.  Now 
listen.  Ah !  There's  Colon — keep  quiet 
now,  don't  talk — hang  it  all,  there's  that 
fellow  who  sits  across  the  aisle  from  me 
in  Latin  one ;  he's  always  butting  in  on 
me  when  I  am  trying  to  do  long-distance 
work — listen!     There's  the  'R.  B.'  giving 


her  'O.  S.'  to  'B.  H.' — Hear  that  low  spark? 
That's  'H.  A.'  shooting  the  baseball  scores. 
Gee !  I  wish  I  could  copy  him,  but  I  can't, 
he's  using  Morse.  I  guess  you  have  heard 
enough.  Take  the  receivers  off  and  I'll 
go  on  with  the  show." 

So  I  did  as  commanded,  thanked  him 
for  the  demonstration,  and  told  him,  in 
earnestness,  what  a  remarkable  person  he 
must  be  to  comprehend  the  technique  of 
such  complex  mechanism. 

"Say,  'Hen'  "  I  inquired,  noticing  the 
contents  of  a  box  reposing  in  the  corner, 
"where  did  you  get  all  of  those  fuses?" 

"Fuses?  Those  are  all  burnt  out.  I 
bought  them  at  a  nickel  apiece,  and  there's 
about  two  dollars'  worth  there  in  the  box. 
I  threw  another  dollar's  worth  away  last 
night  at  a  couple  of  cats.  About  a  week 
ago  'pa'  served  me  with  an  ultimatum  to 
the  effect  that  I  was  to  buy  no  more  fuses, 
so  I  have  hit  upon  a  scheme  whereby  they 
won't  burn  out  so  easily.  I  take  the  top 
off  a  burnt  fuse  and  fill  it  with  tin-foil, 
then  force  it  back  onto  the  fuse,  and  be- 
hold, I  have  a  new  fuse  which  lets  more 
current  thru  than  it  did  when  new !  You 
need  not  tell  anybody  about  it,  for  I  am 
thinking  of  getting  the  idea  patented." 


ARTICLES  IN  THE  AUGUST 
"E.  E," 

H'e  hare  a  number-  of  fine  things  in  \ 

1    store  for  the  August  issue  of  The  \ 

f    Electrical  Experimenter.    Among  1 

I     the  125  articles  already  scheduled  for  \ 

1    the  August  number  the  Editors  take  \ 

1    pleasure  in  announcing   the  follow-  f 

|    ing:—  \ 

"The    Unsinkable  Ship"- — A   solu-  \ 

I     Hon   to    the  submarine  problem   by  I 

1  Hiram  Maxim  himself.  A  feature  \ 
|     article  of  the  highest  class. 

"The    Radio    Bomb" — A    thrilling  | 

1    wireless   story    that   -will   keep   you  l 

1  guessing  every  minute  by  C.  M.  \ 
|  Adams. 

"Standard    Time" — In   which    our  \ 

1    friend,  Thomas  Reed,  discourses  in  his  § 

|    inimitable  style  on  the  use  of  spider  f 

1  webs  and  electricity  in  checking  stand-  1 
1    ard  time.    Don't  miss  it — Readers. 

Selenium,  some  new  electrical  and  \ 

I  scientific  aspects  of  this  little  known  \ 
1    substance  by  Albert  IV.  Wilsdon. 

The    Marvels    of    Radio-Activity.  | 

I  Part  II  by  Icrome  S.  Marcus,  B.  Sc.,  \ 
\    (Ch.  E.) 

A  Homc-Made  Arc  Searchlight  for  I 
1    the  Amateur  by  Frank  M.  Jackson. 

An  Electrolytic  Interrupter  for  Low  § 
1     J^oltages  by  C.  A.  Oldroyd. 

Making  An  Electric  Clock  by  \ 
|     Thomas  Reed. 

The  Present  Status  of  the  Audion  I 
1    by  Dr.  Lee  dc  Forest. 

Complete  Details  for  Building   a  1 

f  20,000  Meter  Undamped  Radio  Re-  I 
|    ceivcr  by  Wm.  Burnett,  Jr. 

1       Amateur  and  Experimental  Radio  \ 

|  Research.  Part  II  by  Raymond  Fran-  \ 
I    cis  Yates. 


"That  is  a  good  scheme,  all  right,"  I  re- 
marked. "I  will  say  nothing  about  it;  but 
what  is  that  arrangement  over  there  on 
the  wall  ?" 

"That  is  a  little  contrivance  of  mine 
whereby  I  am  enabled  to  listen  to  con- 
versation which  takes  place  on  the  first 
floor.  It  consists  of  two  microphones,  a 
battery  and  a  telephone  receiver.  I  in- 
stalled the  microphones  last  Sunday  when 
the  rest  of  the  family  were  at  church ; 
one  is  located  behind  the  boiler  in  the 
kitchen  and  the  other  beneath  the  radiator 
in  the  parlor.  Hold  the  receiver  up  to 
your  ear  and  see  if  you  hear  anything." 


"Yes,"  I  said,  "I  can  hear  people  walk- 
ing around.  Keep  quiet  a  moment."  The 
hissing  and  scraping  noise  gradually  died 
down,  and  then  there  came  to  my  ear  a 
series  of  distorted  words  to  the  effect  that 
".  .  .  I  am  sick  and  tired  of  the  com- 
pany which  Henry  continually  brings  to 
this  house  .  .  .  they  are  a  nuisance 
.  .  .  .  he  is  failing  in  his  Latin  .  .  . 
some  night  .  .  .  throw  his  old  wireless 
out  of  the  window  .  .  ."  Whereupon  I 
dropt  the  receiver  and  said  to  the  un- 
suspecting "Hen,"  "It's  getting  pretty  late. 
I  think  I  had  better  go  home." 

"Hen"  urged  me  to  stay.  "I  will  now 
show  you  the  Tesla  coil.  I  can't  operate 
it  very  much  in  the  evening,  for  it  blinks 
the  lights  and  is  apt  to  cause  trouble  in 
the  family."  He  tinkered  with  the  switch- 
board, made  new  connections,  then  prest 
the  key  with  a  yard-stick  and  blandly  con- 
tinued, "The  sparks  I  am  about  to  show 
you  consist  of  over  one  hundred  and  fifty 
thousand  volts.  They  electrocute  men  over 
in  Sing  Sing  with  two  or  three  thousand 
volts,  so  you  can  imagine  what  a  danger- 
ous current  this  is.  That's  it,"  as  I  backed 
away,  "stand  on  the  rug  there  and  you  will 
be  safe."  "Ham"  Jones  punched  the  key 
with  his  stick  and  long,  purple  sparks  shot 
off  from  the  knobs  of  the  Tesla  coil, 
flicked  about  like  the  fangs  of  a  boa  con- 
strictor and  snarled  and  crackled  like  a 
wounded  "rattler."  I  stood  on  the  rug  in 
mute  admiration  of  this  exhibition  of  arti- 
ficial lightning,  ever  fearful  of  an  impend- 
ing death.  "Hen"  let  the  sparks  play  over 
his  hands  and  even  pulled  sparks  from 
conspicuous  portions  of  my  anatomy. 
Surely,  he  was  a  genius,  a  second  Edi- 
son, a  great  engineer  to  be ;  I  told  him  so, 
but  he  only  laughed  and  told  me  to  wait 
a  moment  and  he  would  show  rr.e  some- 
thing better.  He  picked  a  fine  wire  up 
from  the  floor,  fastened  it  to  the  coil  and 
prest  the  key.  Suffering  cats  ! !  My  shoes 
became  full  of  carpet  tacks  and  I  leaped 
so  high  that  my  head  nearly  hit  the  ceil- 
ing ;  then  down  I  came  again  on  that  red- 
hot  carpet,  and  thus  I  danced  in  agony  un- 
til "Hen"  got  to  laughing  so  hard  that 
he  could  not  keep  his  stick  on  the  key. 
I  was  mad  clean  thru,  but  what  could 
I  do  with  "Ham"  leaning  against  the  wall, 
so  merry  that  the  tears  fairly  rolled  out  of 
his  eyes? 

In  about  ten  minutes  the  "Wizard"  re- 
gained his  former  dignity  and  proffered  an 
explanation  of  his  ingenious  trick.  "Un- 
derneath that  rug  on  which  you  so  kindly 
stood,"  said  he,  "are  a  couple  of  square- 
yards  of  chicken-wire.  I  connect  it  with 
the  coil  by  means  of  this  fine  wire,  when- 
ever I  desire  to  pass  the  spark  into  the 
feet  of  whoever  is  standing  on  the  rug. 
It  works  better  on  the  ladies,  for  the  soles 
of  their  shoes  are  not  as  thick  as  men's. 
I  worked  it  on  our  Parson  the  other  day, 
and  the  sermon  I  got  from  'pa'  a  few 
hours  later  was  sure  brief  and  right  to  the 
point." 

"  'Ham' — er,  Hen,'  that's  a  pretty  clever 
stunt,  even  if  I  was  the  goat,"  I  ventured 
to  say.  "Those  big  sparks  of  yours  are 
more  interesting  than  the  wireless,  but  I 
don't  understand  the  peculiar  way  in  which 
they  seem  to  work.  I  don't  see  why  they 
should  jump  into  my  feet  when  I  do  not 
have  a  second  connection  " 

"Of  course  you  don't,"  interrupted  "Hen." 
"I  can't  explain  the  reason  in  simple  lan- 
guage. Now  if  you  will  step  over  here 
near  the  bed  I'll  show  you  some  more  in- 
teresting ideas.  Before  retiring  I  pull  the 
shade,  shut  the  door  and  turn  on  the  elec- 
tric light.  All  three  of  these  are  arranged 
to  be  worked  electrically  from  a  series  of 
push-buttons  located  near  the  head  of  my 
bed.  Step  over  here  and  I'll  show  you 
how  the  curtain  works." 

(Continued  on  page  217) 


182 


THE  ELECTRICAL  EXPERIMENTER 


July,  1Q17 


20,000  Volts  Direct  Current 


When  a  sufficiently  high  potential  dif- 
ference is  imprest  between  two  parallel 
wires,  or  a  wire  and  concentric  cylinder, 
separated  by  air  or  some  other  gas,  this 
gas  which  for  low  potential  gradients  is  a 


These  machines  are  divided  into  two  sets 
of  ten  machines  each  and  one  set  of  twen- 
ty machines,  each  set  being  driven  by  a 
belt-connected  continuous-current  shunt 
motor.    The  generators  are  mounted  on  in- 


One  of  the  Most  Remarkable  Electric  Generating  Plants  Ever  Built.    It  Is  Used  for  Special 
Test  Work  and  Comprises  Forty  500  Volt  D.C.  Dynamos,  Which,  All  Driven  and  Connected 
Together,  Develop  20,000  Volts  Direct  Current! 


very  good  insulator  breaks  down  and  be- 
comes a  partial  conductor.  The  phenomena 
connected  with  this  character  of  conduc- 
tion thru  gases  are  known  collectively  by 
the  name  corona.  The  failure  of  the  gase- 
ous dielectric  separating  the  metallic  con- 
ductors is  made  evident  by  a  flow  of  cur- 
rent from  one  conductor  to  the  other,  by  a 
power  loss  and,  in  practically  all  cases,  by 
the  appearance  of  light  at  either  one  or 
both  conductor  surfaces.  In  some  cases 
light  appears  in  the  intervening  space. 

Since  the  present  theories  as  to  the  mech- 
anism of  corona  formation  do  not  satis- 
factorily account  for  all  of  the  observed 
phenomena  it  was  decided  to  carry  out  fur- 
ther investigations,  says  G.  W.  Davis  and 
C.  S.  Breese  in  the  Proceedings  of  the 
A.T.E.E.,  in  the  hope  that  when  enough 
data  were  accumulated  some  theory  based 
on  fundamental  principles  and  explaining 
the  observed  phenomena  might  be  evolved. 
With  this  purpose  in  mind  it  was  attempt- 
ed to  simplify  the  conditions  of  corona 
formation. 

A  wire  and  concentric  cylinder  were  used 
in  order  to  make  the  field  radial  and  to 
get  away  from  the  secondary  effects  due  to 
the  high  intensity  electric  field  surrounding 
a  second  wire.  Hydrogen  was  used  as  the 
dielectric  in  order  to  minimize  the  effects 
due  to  changes  in  the  chemical  constitution 
of  the  gas.  When  air  is  used  as  the  dielec- 
tric the  formation  of  ozone  may  produce 
marked  changes  in  the  voltage  necessary 
for  corona  formation.  Continuous  poten- 
tial was  used  in  order"  to  separate  the  ef- 
fects accompanying  a  discharge  from  a 
positive  wire  to  a  negative  tube  from  those 
which  are  characteristic  of  the  discharge 
from  a  negative  wire  to  a  positive  tube. 

The  continuous  (direct  current)  voltage 
used  in  these  investigations  was  obtained 
by  means  of  a  battery  of  forty  500-volt, 
250-watt.  continuous-current,  shunt-wound 
generators  connected  in  series. 


sulating  bases  and  the  shafts  of  the  sepa- 
rate machines  are  connected  by  insulating 
couplings.  In  the  newer  part  of  the  instal- 
lation one  terminal  of  each  machine  is  per- 
manently connected  to  the  frame  of  that 
generator,  in  order  definitely  to  limit  the 
strain  on  the  machine  insulation  to  the 
voltage  generated  in  one  armature. 

The  field  of  each  machine  is  connected 
directly  across  the  armature  terminals,  a 
single-pole  knife  switch  being  included  in 
the  circuit  in  order  that  the  machine  may 
either  be  made  to  generate  or  to  run  idle 
at  will.  These  switches  were  operated  by 
means  of  a  hard  rubber  rod  approximately 
eighteen  inches  in  length,  since  they  may 
be  20,000  volts  above  earth  potential.  The 
generators  were  run  somewhat  below  rated 
speed  in  order  to  limit,  to  a  safe  value,  the 
voltage  generated  with  no  external  resist- 
ance in  the  field  circuit. 


READING  BY  WALL  PAPER  IS 
THE  LATEST  INVENTION. 

Two-wheeled  automobiles  and  torpedoes 
with  mechanical  ears  to  chase  ships  by 
sound  waves  are  brain  products  of  Pro- 
fessor Montraville  M.  Wood,  who  gave  a 
demonstration  of  his  inventions  at  the 
Union  League  Club  recently. 

By  radioactive  paints  he  asserts  an  ex- 
pensive mural  decoration  may  be  manu- 
factured which  will  furnish  so  much  light 
a  person  may  read  by  it. 

"Within  ten  years,"  he  said,  "there  will 
be  plenty  of  nonskidding  automobiles  run- 
ning on  two  wheels,  built  on  the  principle 
of  the  monorail  and  retaining  their  equi- 
librium by  means  of  the  gyroscone." 

The  "listening  torpedo."  of  which  Pro- 
fessor Wood  is  the  inventor,  is  fitted  with 
delicate  mechanical  devices  which  record 
the  sound  waves  made  by  a  ship's  screw 
and  draws  the  torpedo  in  that  direction. 


SEVENTEEN  PICK  UP  FALLEN 
WIRE. 

The  curiosity  of  the  human  race  knows 
no  limit.  In  one  of  our  large  Eastern 
cities,  says  the  Au  Sable  News,  some  men 
were  at  work  installing  a  new  wire  on  a 
busy  street.  For  some  reason  the  part  of 
the  wire  that  was  already  in  place  broke 
near  one  of  the  poles  and  fell  to  the 
ground.  As  the  work  of  erection  was  not 
yet  completed,  the  circuit  was  not  in  serv- 
ice and  the  wire  was  dead — biit  this  fact 
was  known  only  to  the  employees  of  the 
electrical  company.  One  of  the  men,  know- 
ing the  danger  to  the  public  from  fallen 
wires,  but  also  knowing  that  this  partic- 
ular wire  was  harmless,  stood  near  by  to 
note  what  action  the  passing  throng  would 
take.  In  fifteen  minutes  approximately 
200  persons  past  this  point,  and  of  this 
number  twenty-two  showed  some  curiosity 
regarding  the  wire.  Of  the  twenty-two 
who  stopt  seventeen,  all  adults  who  might 
reasonably  be  supposed  to  know  'better, 
stooped  down  and  took  hold  of  the  wire, 
or  at  least  touched  it,  and  then,  finding  it 
harmless,  past  on.  If  the  wire  had  been 
charged  to  a  high  potential,  the  first  of 
the  seventeen  "doubting  Thomases"  would 
have  been  killed. 

HOW  BEES  BECAME  INTERESTED 
IN  TELEPHONY. 

If  C.  W.  Weston,  manager  of  the  Port 
Byron  (New  York)  telephone  company,  had 
been  in  the  honey  business  he  might  have 
welcomed  the  visit  of  a  full  sized  swarm 
of  bees  which  took  refuge  in  the  company's 
terminal  box  located  on  the  main  street  of 
the  village.  After  taking  council  with  the 
local  physician  and  druggist,  and  receiv- 
ing no  satisfactory  advice,  Mr.  Weston's 
mind  wandered  back  to  the  old  days  on  the 
farm  where  on  one  occasion  he  had  been 
compelled  to  test  conclusions  with  several 
skunks.  He  procured  some  bi-sulfate 
of  carbon  and  with  it  saturated  a  handful 
of  cotton  waste  and  packed  it  in  every 
aperture  of  the  terminal  box.  A  careful 
and  cautious  examination  was  made  the 


Bee-lines  and  Telephone  Lines  May  Not  Have 
Any  Common  Bond  Existing  Between  Them, 
But  These  Bees  Evidently  Thought  So  As 
They  Calmly  Proceeded  to  Build  a  Home  In 
a  Telephone  Cable  Terminal  Box  at  Port 
Byron,  N.Y. 

next  evening,  when  it  was  found  the  deadly 
fumes  had  done  their  work.  The  accom- 
panying cut  shows  the  dead  bees.  Note 
the  comb  started  in  the  top  right  hand  cor- 
ner. 


July,  iqi7 


THE  ELECTRICAL  EXPERIMENTER 


183 


A  COMPACT  ELECTRICAL 
HOSPITAL. 

Electro-therapeutics  is  steadily  claiming 
the  attention  of  the  present-day  electrical 
engineer,  owing  to  the  rapid  strides  being 


A  Remarkable  Electrical  Outfit  of  Extreme  Com- 
pactness  Which   Yields   Practically   Every  Form 
of  Current  the  "Doc."  May  Require.    It  Is  Rated 
at  5  Kilowatts. 

made  in  this  field,  competition  acting  as 
the  all-important  stimulant. 

Formerly,  the  electrical  laboratory  of  the 
physician  was  littered  with  various  appara- 
tus, of  no  real  consequence  save  to  occupy 
space.  But  these  conditions  have  been  rap- 
idly overcome,  and  to-day  we  find  that  the 
modern  physician  insists  on  his  apparatus, 
where  electricity  is  employed,  shall  be  as 
compact  and  yet  as  complete  as  possible. 
Various  equipments  have  been  devised  and 
introduced  but  none  of  these  compare  with 
that  illustrated  herewith  which  was  de- 
signed and  built  by  Harry  Rosenthal,  an 
electrical  engineer  of  New  York  City. 

The  applications  of  these  instruments  are 
numerous  a  few  of  which  are  here  men- 
tioned :  X-ray  work,  high  frequency,  Tes- 
la  and  cautery  currents  of  all  intensities. 
Ozone  generation  for  liquid  saturation; 
apparatus  for  the  production  of  mechanical 
vibration  and  air  suction  for  skin  treat- 
ment; also,  the  apparatus  for  the  produc- 
tion of  a  remarkable  new  therapeutic  ray, 
namely,  the  Rosenthal  R-ray. 

The  construction  of  such  an  equipment 
requires  a  fine  degree  of  engineering-  skill, 
considering  the  numerous  apparatus  to  be 
fitted-  into  the  smallest  possible  space. 

Commencing  at  the  top.  of  the  cabinet, 
the  two  X-ray  terminals   will  be  noted, 
which  are  used  to  connect  with  the 
X-ray  tube.    A  milliampere  meter 
is  stationed  on  the  left,  which  is 
used    for   measuring   the  current 
sent  thru  the  tube  when  in  opera- 
tion.    The    control  switch-board 
consists  of  two  white  mar.ble  pan- 
els.    Vario,us    binding    posts  are 
placed  in  front  of  the  panel,  each 
pair  being  used  for  a  definite  pur- 
pose, and  the  connections  are  made 
thru    flexible    copper  conductors. 
Levers  and   switch    arms  are  stationed 
about  the  panel  suitable  for  controlling  the 
many  kinds  of  currents  supplied.    The  two 


ball  posts  at  the  extreme  right  hand  are 
used-  for  connecting  the  apparatus  used  in 
the  production  of  the  X-ray.  Each  pair  of 
terminals  are  controlled  by  an  individual 
switch.  Apparatus  for  applying  the  gen- 
erated ozone  may  be  seen  in  the  upper 
left  corner,  and  this  consists  of  a 
special  glass  tube  fitted  with  a  fine 
nozzle. 

The  generating  and  main  instru- 
ments are  contained  in  the  lower  por- 
tion of  the  cabinet.  A  motor-driven 
suction  pump  is  utilized'  for  the  pro- 
duction of  mechanical  vibration  and 
the  device  which  is  applied  to  the  pa- 
tient is  noted  on  the  left 
side  of  the  cabinet.  It  con- 
sists of  nothing  more  than 
a  rubber  tube  placed  in  a 
special  receptacle  and  con- 
nected to  the  pump  by 
means  of  another  rubber 
tube.  A  second  pump  is 
used  to  force  out  the  gen- 
erated ozone.  This  is  made 
in  a  glass  tube  hung  on  the 
door  of  the  cabinet  seen  at 
the  right.  The  terminals 
are  connected  to  the  high 
frequency  circuit  by  means 
of  brass  clips  when  the 
door  is  closed,  while  the 
ozone  is  past  thru  a  rub- 
ber tube  to  the  pump,  and 
finally  to  the  glass  bottles 
as  above  mentioned.  Four 
high  tension  condensers  are 
employed  and  these  are 
placed  in  each  corner  of  the  lower 
compartment.  The  Leyden  jars  con- 
tain salt  water  as  the  interior  coat- 
ing, and  connection  is  made  thru  a 
carbon  rod.  The  Tesla  transformer 
is  placed  on  the  door  of  the  cabinet 
and  its  connections  are  terminated 
at  copper  jaws  which  interlock  on  metal 
lugs  when  the  door  is  closed.  The 
high  tension  current  is  supplied  by  a  5- 
kilowatt  closed-core  transformer  and  this 
is  placed  in  the  base  of  the  cabinet.  Its 
secondary  terminals  are  led  to  a  special 
rotary  spark  gap  which  is  placed  in  the 
rear. 


A  NEW  TELEGRAPH  TEACHING 
MACHINE. 

The  instrument  here  illustrated  is  intend- 
ed to  simplify  the  details  of  telegraphy.  It 
is  operated  without  the  aid  of  an  instructor. 
All  that  the  beginner  nas  to  do  is  to  follow 
the  chart  and  execute  the  dots  and  dashes 
as  they  are  printed  thereon.  It  was  in- 
vented by  Air.  George  J.  Little  and  is  called 
the  Siniplograph. 

The  object  of  having  a  key  for  each  let- 
ter is  to  allow  for  the  use  of  both  hands  si- 
multaneously if  desired.  This  gives  the 
beginner  plenty  of  finger  exercise.  This 
instrument  is  claimed  to  represent  distinct 


A  TELEGRAPH  SOUNDER  THAT 
WORKS  ON  A.C. 

Telegraph  sounders  all  operate  on  direct 
or  continuous  current,  such  as  that  from 
a  battery.    But  here  is  one  that  clicks  away 


Something  New  in  Telegraph  Sounders — One  That  Actually 
Works  Efficiently  On  Low  Voltage  Alternating  Current  From 
a  Step-down  Transformer. 

at  a  merry  pace  on  alternating  current! 
In  brief,  the  current  from  the  line  thru  the 
main  line  relay  keeps  the  armature  normally 


The  "Simplograph" — An  Attempt  to   Make  the  Learning 
of  the  Telegraph  Code  as  Simple  as  Possible.    A  Buzzer 
Sounds  the  Signals  for  Radio  Students. 

advantage  over  the  single  key  or  other  me- 
chanical devices  that  are  now  on  the  mar- 
ket. A  dry  cell  or  two,  connected  up  to 
the  keyboard  here  shown,  causes  the  buz- 
zer mounted  thereon  to  respond  every  time 
the  keys  are  deprest.  Incoming  signals  are 
received  on  the  buzzer  also.  The  key  be- 
fore each  letter  on  the  chart  must  be  de- 
prest the  proper  number  of  times  for  the 
corresponding  dots  and  dashes.  The  device 
should  prove  of  value  lO  students. 

against  the  front  contact,  permitting  cur- 
rent from  a  small  alternating  current  trans- 
former to  energize  a  winding  on  a  lamina- 
ted iron  core.  On  opening  the  main  line 
and  consequent  demagnetization  of  the  re- 
lay the  armature  makes  contact  with  the 
back  stop,  thus  energizing  one  coil  of  the 
transformer.  The  sounding  lever  of  the 
transformer,  fulcrumed  on  the  center  or 
common  leg  of  the  laminated  core  of  the 
transformer,  is  alternately  held  in  contact 
with  adjusting  screws  kept  continuously 
magnetized  by  a  permanent  magnet.  The 
function  of  the  magnet  is  to  prevent  chat- 
ter and  hum  of  instrument  and  renders  the 
telegraphic  sounds  uniform. 

The  small  transformer  case  (including 
secondary  voltage  regulator)  measures  3x6x 
inches  high.  This  transformer  is  ca- 
pable of  operating  fifteen  or  twenty  sound- 
ers simultaneously.  Energy  taken  by  the 
sounder  is  approximately  four  watts ;  the 
magnetizing  energy  taken,  by  transformer 
is  so  small  that  the  primary  may  be  left  in 
circuit  continuously,  as  the  ordinary  inte- 
grating watt  hour  meters  will  not  indicate 
the  energy  consumed. 

The  function  of  the  contacts  on 
trans-former  is  to  adjust  voltage  to 
best  operation  o-f  sounder.  Under 
proper  conditions'  it  is  practically 
impossible    to    tell    whether  the 
sounder  is  connected  to  an  alternat- 
ing or  direct  current  circuit.  A 
trial  equipment  in  a  railway  tele- 
graph office  has  operated  success- 
fully on  a  sixty  cycle  circuit,  but 
the  device  operates  equally  as  well 
without  any  change  on  twenty-five  cycles. 
A  loud,  clear  sound  is  obtained  by  a  move"- 
ment  of  but  5/1000  inch  of  the  leveV. 


THE  ELECTRICAL  EXPERIMENTER 


July,  IQ17 


A  36-INCH  SPARK  TESLA  COIL 
FOR  LECTURERS. 

Probably  the  most  amazing  and  spectacu- 
lar of  all  electrical  apparatus  is  the  Tesla 
or  High  Frequency  Coil  and  no  electrical 


3  Kilowatt  Tesla  Coil  in  Full  Activity,  Giving 
36  Inch  Sparks.  The  Sparks  May  Be  Taken 
Into  the  Body  as  Their  Ultra-high  Fre- 
quency Renders  Them  Harmless.  This  Is 
the  Class  of  Apparatus  with  Which  Our 
Pseudo- professors  of  the  Stage  Are  Wont  to 
Over-awe  and  Mystify  Us. 

laboratory  or  lecturer's  outfit  is  complete 
without  such  an  equipment.  It  is  most  as- 
tonishing to  be  able  to  draw  coiling,  flam- 
ing sparks  from  a  few  inches  to  several 
feet  in  length  from  your  body  to  the  coil 
without  the  slightest  injury  or  discomfort. 
Hundreds  of  other  interesting  and  strange 
experiments  may  be  performed,  such  as 
lighting  large  numbers  of  vacuum  or  Geiss- 
-  ler  tubes  of  various  brilliant  colors  by 
merely  holding  them  in  the  hand  near  the 
coil  without  any  wires  whatever.  The  or- 
dinary incandescent  lamp  will  glow  with  a 
pale  green  light  when  held  near  the  coil  or 
connected  to  it.  Various  minerals  and 
many  precious  stones  will  glow  and  fluor- 
esce with  unusual  lights  and  colors  under 
its  influence.  Its  sparks  when  occurring 
over  large  flat  areas  produce  a  large  quan- 
tity of  ozone.  A  wire  bent  in  the  shape  of 
the  letter  "S"  and  balanced  on  the  point 
of  a  pin  from  its  center,  will  rotate  as  a 
static  motor  with  flames  shooting  from  its 
ends  when  the  pin  is  connected  to  rne  pole 
of  the  machine.  All  of  these  experiments 
and  hundreds  of  others  may  be  performed 
without  the  slightest  danger,  as  the  fre- 
quency of  the  current  is  so  hrgh  as  to  rend- 
er it  harmless.  You  cannot  even  feel  the 
spark  if  it  is  allowed  to  jump  to  a  piece  of 
metal  held  in  -the  hand,  but  where  the  spark 
jumps  directly  to  the  skin  it  gives  a  slight 
pricking  sensation  only  on  the  spot  where 
the  spark  strikes.  The  coil  has  a  movable 
contact  on  the  primarv  for  tuning  it  to  the 
secondary.  Proper  tuning  between  primary 
and  secondary  is  important  for  satisfactory 
results. 

The  Tesla  Coil  rated  at  li  K.W.  will  give 
a  purple  flame  about  9  inches  long  when 
operating  in  proper  tune  or  resonance,  and 
when  the  electrodes  are  separated  to  a 
greater  distance  each  is  surrounded  by  a 
fan  of  coiling  sparks  several  inches  in 
length.  It  requires  a  condenser  of  ap- 
proximately .01  M.F. 

The  coil  shown  in  full  activity  is  produc- 
ing^ 36-inch  high  frequency  sparks  and  is 
excited  with  a  3  K.W.  radio  transformer, 
a  spark  gap  and  a  high-tension  condenser 
of  .03  microfarad  capacity.  These  outfits 
operate  from  110  volt.  60  cycle  A.C.  cir- 
cuits and  form  an  excellent  apparatus  for 
the  lecture  and  stage  platform. 


ELECTRIC  UNA-FON  MAKES 
MUSIC  TO  BEAT  THE  BAND. 

The  electric  Una-Fon  here  illustrated  is 
played  from  a  keyboard,  the  keys  of  which 
are  exactly  the  same  as  those  of  a  piano. 
No  previous  experience  is  necessary  for  its 
successful  use  and  any  piano  selection  can 
be  played  on  it,  both  harmony  and  melody. 
The  instrument  is  said  to  mark  a  new  de- 
parture in  tone  quality,  it  having  been  lik- 
ened by  some  to  the  Vox  Humana  of  a 
pipe  organ.  The  Una-Fon  may  be  played 
either  soft  or  loud  and  is  equally  adapted 
to  use  in  theater  or  in  the  open.  In  street 
work,  under  fair  conditions,  it  may  be  heard 
several  blocks  ;  it  has  wonderful  volume  and 
carrying  capacity.  On  the  water  its  clear, 
brilliant  tone  carries  great  distances.  The 
maintenance  expenses  is  kept  at  a  low  fig- 
ure by  reason  of  the  storage  battery  sup- 
plied with  each  set,  cutting  the  operating 
cost  down  to  two  or  three  cents  an  hour. 

Each  tone-producing  unit  is  a  patented 
special  alloy,  nickel  plated,  concave  steel 
bar,  mounted  over  a  special  resonator  on  a 
solid  oak  frame,  with  an  electric  playing 
action  attachment.  It  remains  in  perfect 
adjustment,  produces  a  fast  vibrating  stroke 
and  wields  a  large  composition  mallet  that 
brings  out  the  full  beauties  of  the  tone.  The 
instrument  is  not  affected  by  atmospheric 
conditions,  and  retains  its  tone  at  all  times. 

The  various  electric  actions  are  firmly 


keyboard  is  connected  thru  a  ten-foot  flexi- 
ble cable. 

electric  musical  instruments  such  as  the 
Xylophone,  Alarimbaphone,  etc.,  as  these 
can  be  played  from  the  same  keyboard. 

The  third  unit  of  this  instrument  com- 
prises a  small,  light  battery  case  for  hold- 
ing dry  cells  of  standard  size,  which  is 
constructed  with  fastenings  so  that  it  may 
be  attached  to  any  part  of  the  machine  thai 
is  found  convenient.  The  three  parts  of  the 
apparatus  are  connected  by  a  single  ca- 
ble, of  such  length  that  the  whole  apparatus 
can  be  instantly  attached  to  any  of  the 
standard  instruments  now  in  use. 


RADIO  IN  DENMARK. 

Denmark  has  organized  at  Svenborg  a 
school  of  radiotelegraphy  with  the  ob- 
ject of  giving  complete  professional  in- 
struction allowing  pupils  to  obtain  the 
necessapy  certificate  to  operate  wireless 
stations. 


A   Novel   Electric   Musical  Instrument 
Which  Is  Played  from  a  Keyboard  Ex- 
actly Like  That  of  the  Piano. 


mounted  on  solid  oak  cross-pieces  on  nick- 
el plated  floor  rack  that  occupies  minimum 
space  and  can  be  moved  anywhere.  The 


LARGEST  STORAGE  BATTERY  IN 
UNITED  STATES. 

The  Detroit  Edison  Co.,  has  in  service 
in  its  Congress  Street  Sub-station  the  larg- 
est storage  battery  in  the  United  States. 

This  installation  is  of  interest,  not  only 
on  account  of  the  high  capacity  of  the  bat- 
tery but  also  as  showing  the  most  recent 
practise  in  storage  battery  engineering  as 
applied  to  urban  direct  current  lighting 
systems. 

This  battery  is  kept  fully  charged  and 
connected  to  the  bus  bars  at  all  times  in 
order  to  insure  against  an  interruption  of 
6-rvice.  In  case  of  failure  of  the  custom- 
ary sources  of  energy  the  battery  is  in- 
stantly available  for  use. 

The  -battery  consists  of  150  large  Exide 
cells  having  a  capacity  of  25,200  amperes 
at  110  volts  for  one  hour  and  80,000  am- 
peres for  ten  minutes. 

Elaborate  endcell  switches  and  battery 
control  switchboard  are  employed  for  prop- 
erly switching  in  the  cells,  charging  them 
and  regulating  the  counter  electro  motive 
force  of  the  battery. 

Many  of  the  largest  central  power  sta- 
tions are  equipt  with  storage  batteries  sim- 
ilar to  this  one,  for  the  purpose  of  helping 
to  carry  the  peak  load,  which  may  last 
only  an  hour  or  so,  and  which  does  not 


The  Gigantic  "Standby"  Storage  Battery  of  the  Detroit  Edison  Co.,  Said  To 
Be  the  Largest  Storage  Battery  in  the  United  States. 


Special  octave  couplers  produce  a  twen- 
ty-piece brass  band  volume.  The  detacha- 
ble keyboard  enables  the  addition  of  other 


warrant  the  installation  of  additional  dy- 
namos to  carry  the  mean  average  load,  plus 
the  peak  load. 


July,  1917 


THE   ELECTRICAL  EXPERIMENTER 


185 


GRAFITE-SELENIUM  CELLS. 

The  new  type  of  Selenium  Cell  here  il- 
lustrated and  brought  out  in  England,  pos- 
sesses distinct  advantages  over  all  for- 
mer types,  chiefly  owing  to  the  use  of  the 
non-oxidizahle  grafite  in  place  of  copper, 
gold  or  platinum  for  the  electrodes  bridged 
  -^Sjl  over  by  the  selenium. 

These  cells  are 
Bf^^^^l^iF^  claimed  to  have  great 
^llllwf*         ^  llillli  stability,    and  should, 

■||||\  1  v'<;    g|  IjfJ    v  .ill  !•!••!>  n  -  i.  n 

PPi  lill  I  (  I  rem. mi  effective  Lot 
|l3|h|' i|  !!  I  [  "' I  many  years.  As  no 
wil  l  III  I  H  wire  is  used  in  their 
W|  construction,  short-cir- 
BBKgjwipM  cuiting  is  excluded. 
^IBIlii!^^  Their  efficiency,  meas- 

ured by  the  useful  current  obtainable 
on  illumination,  is  well  above  that  of  the 
best  previous  types.  This  claim,  put  into 
figures,  is  as  follows : 

With  a  sensitive  selenium  surface  of  5 
sq.  cm.,  and  a  voltage  of  20,  the  additional 
current  obtainable  at  various  illuminations 
is  as  follows: 

1  metre-candle   J4  milliampere 

50  metre-candles   1  milliampere 

500  metre-candles   2  milliamperes 

The  cells  are  constructed  under  the  su- 
pervision of  Dr.  Fournier  d'Albe,  A.R.C. 
Sc.,  the  inventor  of  the  Type-reading  Op- 
tophone, and  are  made  in  two  standard 
patterns.  Type  A,  suitable  for  working 
relays ;  resistance  about  10,000  ohms.  Type 
B,  suitable  for  use  as  Photophone  Receiv- 
ers, or  for  other  applications  of  intermit- 
tent light ;  resistance  about  100,000  ohms. 
Type  A  has  a  sensitive  surface  of  5  sq. 
cm.,  and  is  guaranteed  to  yield  the  currents 
above  specified.  Type  B  has  a  sensitive 
surface  of  0.3  sq.  cm.,  and  is  guaranteed 
to  detect  an  intermittent  illumination  of 
25  metre-candles  with  a  sensitive  telephone 
receiver  and  a  batter}'  of  20  volts.  Larger 
patterns  are  constructed  'by  special  ar- 
rangement. The  size  of  standard  cells  is 
2x2x1  inches  overall  and  weight  2%  ounces. 

HANDY  RESISTANCE  UNITS. 

Something  every  electrical  man  wants  at 
some  time  is  a  standard  resistance  unit. 
Each  resistance  unit  of  the  type  illustrated 
is  mounted  in  a  block  of  hard  wood  with 
shellac  finish.  The  terminals  of  the  resist- 
ance are  attached  to  spring  binding  posts. 
The  resistance  unit  blocks  are  1 54  inches 
square  and  2T/2  inches  high,  and  can  be  ar- 
ranged together  like  blocks  in  various  com- 
binations. The  resistance  wire  is  wound 
bifilar  on  a  large  diameter  spool  which  is 
concealed  in  the  block.    All  units  are  ad- 


New  Form  of  Handy  Resistance 
Unit.      It    Is    Supplied    in  Any 
Size  Desired. 


justed  to  within  one-twentieth  of  one  per 
cent  accuracy.  Each  unit  will  safely  carry 
a  load  of  2  watts  which  will  produce  a  final 
temperature  rise  of  50°C. 

These  resistance  units  will  be  found  of 
great  convenience  for  obtaining  any  desired 
resistance  value.  (The  desired  value  is 
quickly  obtained  by  series,  parallel,  or 
series-parallel  combinations  of  the  units)  ; 
for  shunting  a  galvanometer  to  make  it 
critically  damped,  or  to  reduce  its  sensibil- 
ity; making  up  the  ratio  coils  of  a  slide- 
wire  bridge  or  a  Kelvin  double-bridge  ;  mul- 
tiplying the  scale  of  a  voltmeter  or  watt- 
meter by  increasing  its  resistance;  building 
up  a  "volt  box"  to  use  in  connection  with  a 
potentiometer  and  for  building  up  resist- 
ance combinations  to  teach  students  to  cal- 
culate and  measure  the  same. 


A  PRECISION  TYPE  OF  RHEOSTAT. 

ft  is  often  desirable  in  electrical  work, 
especially  when  making  delicate  measure- 
ments, to  have  available  a  finely  adjustable 


A  Precision  Type  of  Rheostat  of  Par- 
ticular   Value    in    All    Fine  Electrical 
Measurements. 


resistance  such  as  the  one  illustrated.  This 
particular  rheostat  is  of  English  manufac- 
ture and  comprises  a  metal  tube  covered 
with  insulation  and  over  which  many  turns 
of  closely  wound  bare  resistance  wire  are 
placed. 

By  means  of  the  usual  hand  wheel 
projecting  at  the  right  and  the  geared 
worm,  it  becomes  possible  to  move 
the   adjustable    spring   contact  very 
accurately  along  the  resistance  coil. 
In  order  that  this  movement  shall 
not  require  too  many  turns  of  the 
hand  wheel,  the  pitch  of  the  thread 
on  the  worm   shaft   is  made  quite 
long  or  about  one-half   inch.  The 
particular    precision    rheostat  illus- 
trated is   designed  to  be 
mounted  on   the  rear  of 
a  switch-board  panel  and 
the    regulating    knob  or 
wheel      only  projecting 
thru  on  the  face  of  the 
panel.     It    should  prove 
ideal  for  all  kinds  of  elec- 
trical  measuring  circuits, 
as  well  as  wireless  circuits. 


A  VERTICAL  TABLE  FAN. 

The  advantages  of  the  new  electric  table 
fan  shown  in  the  accompanying  illustration 
lie  in  the  fact  that  it  can  be  used  on  a 
dining-room  table  or  a  flat  top  desk  without 
disturbing  the  pa- 
pers or  articles 
on  the  desk's  or 
table's  surface. 
The  breeze  is  dis- 
tributed in  a  strata 
of  about  one  foot 
above  the  table 
level,  and  has  a 
radius  of  six  to 
ten  feet.  There- 
fore, everyone 
seated  within  that 
radius,  receives  a 
continuous  breeze 
instead  of  the  in- 
termittent and 
often  annoying 
strong  blast  of  the 
ordinary  oscillat- 
ing fan. 


Table  Fan  for  Use  on 
Dining-room  or  L  I- 
brary   Tables   to  Give 
All-around  Breeze. 


ELECTRIC  TAG  MARKER  SAVES 
TIME. 

The  marking  of  price  tags  in  dry-goods, 
and  department  stores  particularly,  is  a 
slow  and  tedious  task  if  done  by  hand. 
The  simple  motor-driven  tag  marker  shown 
changes  all  this.  By  its  use  2,400  tags  can 
be  printed  in  an  hour. 

The  mechanism  of  this  tag  marker, 
which  is  driven  by  a  1/20  h.p.  motor  thru 
a  worm  and  gear,  consists  of  a  set  of 
cams,  which  move  an  endless  chain  of 
aluminum  trays  beneath  a  miniature  type 
chase.  The  tags  are  printed  as  they  move 
along  on  these  trays.  The  trays  are  hand 
fed.  A  tag  is  placed  in  each  tray  beneath 
a  clip  which  holds  the  tag  in  place  from 
the  time  it  is  fed  into  the  machine  until 
marked  by  a  downward  movement  of  the 
type  chase.  This  insures  uniform  regis- 
ter of  the  marking.  When  the  tag  is 
printed  it  is  automatically  released  from 
the  clip  and  discharged  from  the  tray  at 
the  end  of  the  machine. 

The  machine  will  accommodate  any  size 
or  shape  of  tag  up  to  1J4  inches  wide,  of 
any  thickness  from  thin  paper  up  to  cards 
3/32  inch  thick.  The  type  chase  is  ad- 
justable to  adapt  it  to  various  sizes  of 
type  and  is  capable  of  marking  as  mam- 
as seven  lines  with  fifteen  small  characters 
or  nine  large  characters  on  a  line.  The 
type  commonly  used  is  of  metal,  full  twelve 
point  (r6  inch  high).  With  the  usual  set 
up  of  the  chase,  it  is  possible  to  print  both 
the  tag  and  the  stub  with  the  words  Lot, 
Size,  Price  and  some  other  word  if  needed. 


The  new  battleship  Ten- 
nessee will  use  27,500  electrical  horsepower, 
enough  power  to  furnish  heat,  light  and 
power  for  a  city  of  100,000  inhabitants. 


The  Electric  Tag  Marker  Prints  2,400  Price  or  Other  Tags 
an  Hour. 


This  tag  marker  is  compact,  portable, 
very  quiet  in  operation  due  to  the  worm 
drive,  and  only  weighs  45  nounds. 


186 


THE  ELECTRICAL  EXPERIMENTER 


July,  1917 


Notice  to  All  Radio  Readers 

As  most  of  our  radio  readers  are  undoubtedly  aware,  the  U.  S.  Government  has  decided  that  all  Amateur  Wireless  Stations, 
whether  licensed  or  unlicensed,  or  equipt  for  receiving  or  transmitting,  shall  be  closed. 

This  is  a  very  important  consideration,  especially  to  those  who  are  readers  of  THE  ELECTRICAL  EXPERIMENTER, 
for  the  reason  that  we  desire  to  continue  to  publish  valuable  articles  in  the  wireless  art  from  time  to  time,  and  which  may 
treat  on  both  transmitting  and  receiving  apparatus.  In  the  first  place,  there  are  a  great  ma-ny  students  among  our  readers 
who  will  demand  and  expect  a  continuation  of  the  usual  class  of  Radio  subjects,  which  we  have  publisht  in  the  past  four 
years,  and  secondly,  there  will  be  hundreds  and  even  thousands  of  new  radio  pupils  in  the  various  naval  and  civilian  schools 
thruout  the  country,  who  will  be  benefited  by  up-to-date  wireless  articles  treating  on  both  the  transmitting  as  well  as  receiv- 
ing equipment. 

Therefore ,  and  in  view  of  the  foregoing  explanation,  we  feel  sure  that  every  reader  will  thoroly  understand  that  altho 
articles  on  transmitting,  as  well  as  receiving,  apparatus  may  appear  from  time  to  time  in  these  columns,  he  is  not  permitted  to 
connect  up  any  radio  apparatus  whatsoever  to  any  form  of  aerial. — The  Editors. 


Testing  Radio  Units  With  Dummy  Antenna 


THE  accompanying  illustrations, 
figures  1,  2  anil  3,  show  the  equip- 
ment used  for  testing  radio  units  of 
the  Federal  Telegraph  Company 
with  a  Dummy  Antenna,  as  utilized 
at  the  Palo  Alto,  California,  laboratory.  It 
was  possible,  with  this  antenna,  to  repro- 
duce practically  any  antenna  found  in  com- 
mercial radio  telegraph  stations,  and  there- 


By  FRANK  C.  PERKINS 

are  likely  to  disturb  the  ether  for  hundreds 
of  kilometers  in  all  directions.  A  need 
arises,  therefore,  for  a  dummy  antenna,  or 
a  radio  load  for  testing  radio  generators, 
which  shall  not  seriously  stir  up  and  vex 
the  ether  in  the  vicinity.  The  problem  is 
to  load  the  generator  but  to  suppress  the 
output  beyond  a  short  range.  This  is  a 
problem  in  radio  inefficiency,  and  is  just 


The  Accompanying  Views  Show  a  Colos- 
sal "Dummy"  Antenna  Erected  by  a 
Large  Radio  Concern  in  Palo  Alto,  Cali- 
fornia, for  the  Purpose  of  Testing  Out 
Large  Poulsen  Arc  Generators  Now  Being 
Extensively  Used  by  Uncle  Sam.  The  An- 
tenna Is  262.5  Ft.  Long  by  136.5  Ft.  Wide. 


fore  observe  the  performance  of  the  wire- 
less s€ts  under  practical  operating  condi- 
tions. 

The  Arc  Radio  Transmitters  are  now 
produced  for  commercial  uses  in  ratings 
from  5  to  500  kilowatts,  and  the  350  K.W. 
unit  has  an  overload  rating  of  500  K.W. 

It  is  pointed  out  that  when  electrical  en- 
gineers test  a  dynamo  they  are  not  likely 
to  disturb  engineering  operations  in  other 
buildings,  or  even  in  other  parts  of  the 
same  building.  When,  however,  they  test 
a  radio  plant  of  considerable  power  they 


the  reverse  of  the  ordinary  problem^  of  the 
radio  engineer,  which  is  to  load  his  gen- 
erator as  efficiently  as  possible,  so  that  the 
effects  may  be  manifested  at  a  great  range. 

The  dummy  antenna  at  Palo  Alto  con- 
sists of  a  series  of  horizontal  galvanized 
iron  wires  in  five  layers,  so  arranged  as  to 
be  capable  of  forming  an  air  condenser  of 
adjustably  variable  capacity  up  to  about 
one-thirtieth  of  a  microfarad.  With  such 
a  capacity  carrying  250  amperes,  at  20,000 
cycles  per  second,  the  voltage,  neglecting 
all  losses,  would  be  approximately  64,000. 


Sixty-four  kilovolts  driving  250  amperes 
in  quadrature  would  develop  16  megaw:atts 
of  reactive  power. 

It  is  pointed  out  that  an  active  power 
rating  of  200  K.W.  W'Ould  thus  only  de- 
mand a  little  more  than  1  per  cent  of  dissi- 
pation factor.  It  is  evident  that  this  dum- 
my has  large  dissipation  possibilities.  In 
making  radio  units  of  larger  capacity  than 
have  heretofore  been  attempted, 
it  was  found  necessary  to  pro- 
vide a  dummy  antenna  which 
could  be  used  for  testing  Fed- 
eral-Poulsen  Arc  converters  of 
various  sizes.  Because  of  the 
large  units  contemplated,  and 
since  interference  with  nearby 
commercial  stations  had  to  be 
avoided,  the  type  of  construction 
shown  in  the  accompanying  il- 
lustrations was  developed. 

It  may  be  stated  that  this  af- 
forded capacities  up  to  0.031 
microfarad,  and  by  being  of  such 
construction  as  to  have  a  low 
effective  height,  caused  a  min- 
imum of  interference.  The  an- 
tenna consists  of  five  parallel 
layers  of  wires  spaced  5  ft.  apart 
vertically.  The  wires  in  each 
layer  are  2  ft.  apart  horizontally 
and  there  is  a  10  ft.  clearance 
between  the  ground  and  the  low- 
est point  in  the  bottom  layer. 
The  bottom  layer,  which  is 
grounded,  is  136.5  ft.  wide,  with 
a  maximum  length  of  262.5  ft. 

It  is  of  interest  to  note  that 
the  other  layers,  insulated  from 
ground,  are  20  ft.  shorter  and 
41  ft.  narrower.  The  insulated 
layers  have  fifty-one  wires  each 
and  the  grounded  layer  sixty-six 
wires.  The  two  outer  wires  on  each  side  of 
the  four  top  layers  are  size  No.  2,  because 
the  edge  wires  are  not  shielded  as  well  as 
the  others  and  it  was  desired  to  prevent  the 
corona  which  would  otherwise  appear  at  the 
edges  of  these  layers.  With  this  exception, 
No.  14  galvanized  telephone  wire  was  used 
in  all  layers,  and  the  wires  are  fastened  at 
each  end  to  1-in.  stranded  cables.  Altho 
galvanized  wire  is  not  generally  considered 
good  practise  in  radio  work,  it  was  never- 
theless used  on  this  antenna  because  with 
the  large  number  of  -  wires  employed  the 


July,  1917 


THE  ELECTRICAL  EXPERIMENTER 


187 


resistance  could  be  kept  within  the  usual 
limits. 

For  convenience  the  five  parallel  layers 
of  the  antenna  are  numbered  from  the  top 
down.  Layers  Nos.  1  to  4  inclusive  are 
well  insulated,  and  a  long  length  of  halyard 


length  so  as  to  secure  the  parabolic  curve 
in  the  1  -in.  cables.  Two  short  posts, 
exactly  200  ft.  apart,  were  set  up  on  the 
site  with  several  intermediate  stakes  be- 
tween. The  wire  was  unwound  from  the 
reel  near  one  of  the  posts  and  run  out  with 


San    Diego,    Pearl    Harbor    and  Cavite. 


RADIO  IN  PERU  AND  SPAIN. 

Measures  have  been  adopted  by  the  Peru- 
vian Government  authorizing  the  construc- 
tion of  a  telegraph  line  between  the  cities 
of  lea  and  Castrovirreyna  at  a  cost  of  6,300 
Peruvian  pounds  ($30,659),  and  the  installa- 
tion of  wireless  stations  at  various  points 
in  the  basin  of  the  Amazon  at  a  cost  of 
10,000  Peruvian  pounds  ($48,665).  1A 
Peruana  also  notes  that  a  new  telegraphic 
code  has  been  compiled  by  the  Department 
of  Telegraphs  and  Mails,  and  a  commission 
of  Government  officials  has  been  appointed 
to  examine  the  code  and  to  make  a  recom- 
mendation as  to  its  adoption. 

The  new  postal  building  at  Madrid,  Spain, 
is  to  be  fitted  with  wireless  telegraph  and 
telephone  apparatus  of  the  latest  pattern. 
The  transmitter  will  be  of  the  same  type 
as  that  which  made  possible  the  transmis- 
sion of  the  human  voice  from  New  York  to 
Honolulu  and  Paris.  From  the  central 
tower,  90  metres  high,  wire  will  be  stretched 
to  the  three  other  posts,  of  which  two  are  on 
the  front  and  the  other  on  the  back  of  the 
building.  The  receiving  apparatus  will  com- 
prise a  certain  type  of  telephonic  relay  al- 
lowing the  intensity  of  the  feeble  current 
received  to  be  amplified  500  times. 


Wonderful  Night  Photograph  of  "Dummy"  Antenna  in  Full  Activity.  Note  the  Corona 
Glow  on  the  Wires  Caused  by  a  Charge  from  a  300  K.W.  Federal- Poulsen  Arc  Generator. 


between  the  insulation  and  the  supporting 
towers  was  provided  in  order  to  permit  of 
putting  in  more   insulation   with  suitable 


this  became  neces- 
Obviouslv,  if  this 


corona  shields  in  case 
sary  at  a  later  date, 
were  done,  only  layers  Nos.  1  and  5  could 
be  used,  because  the  large  diameter  of 
shields  necessary  with  such  a  long  string 
of  insulators  would  otherwise  interfere,  the 
layers  being  only  5  ft.  apart. 

It  will  be  observed  that  provision  was 
also  made  for  the  installation  of  corona 
shields  on  the  insulator  strings  now  used, 
but  no  trouble  of  this  sort  has  been  experi- 
enced thus  far  and  these  shields  have  not 
been  added.  Beneath  layer  No.  5  are  two 
single  wires  which  are  normally  connected 
and  have  a  separate  lead  running  into  the 
laboratory.  These  have  a  capacity  of  0.002 
microfarad.  By  various  combinations  of 
these  wires  with  different  layers  of  the 
antenna,  a  considerable  number  of  capaci- 
ties are  available,  the  maximum  being  ob- 
tained when  layers  Nos.  1,  3  and  5  are 
connected  as  the  earth  side  of  the  system 
and  Nos.  2  and  4  are  connected  with  the 
two  single  wires  as  the  high  potential  side. 
With  this  combination  the  capacity  is  0.031 
microfarad. 

The  jumpers  used  for  connecting  the 
various  layers  consist  of  V/2  in.  copper  tube 
provided  with  suitable  clamps  and  fittings 
so  that  shifting  to  different  capacities  is  an 
easy  matter.  The  capacities  most  com- 
monly used  are  0.006,  0.012,  0.017  and  0.024 
microfarad.  Many  others  are  available. 
Before  deciding  upon  the  exact  lengths  of 
the  antenna  wires,  it  was  noted  that  with 
evenly  spaced  equal  loading  the  1-in.  cables 
to  which  the  wires  are  attached  would  as- 
sume a  parabolic  curve.  The  lengths  of  the 
wires  in  each  layer  were  calculated  accord- 
ingly, and  thus  a  uniform  tension  is  secured 
in  the  individual  wires  of  each  layer  with- 
out 'excessive  pull  on  the  pole  supports. 

Previous  to  the  tests,  it  was  desirable  to 
tabulate  the  length  of  each  wire,  which  was 
calculated  to  the  nearest  0.01  ft.  A  con- 
venient scheme  was  then  devised  for  cut- 
ting the  large  number  of  wires  to  exact 


a  "come  along"  grip  to  the  desired  length 
beyond  the  second  post. 

There  was  steel  tape  with  its  zero  on  the 
second  post  stretched  out  beyond  it  with 
the  wire  and  the  end  of  the 
wire  was  placed  at  the  exact 
tape  reading  before  signaling. 
Having  the  end  of  the  wire 
held  firmly  in  place  on  the  tape, 
a  man  near  the  reel  put 
steady  tension  in  the  wire 
by  means  of  a  "come  along" 
grip  until  the  wire  was  just 
raised  above  the  intermediate 
stakes,  and  then,  upon  signal 
from  the  man  at  the  tape,  the 
wire  was  cut  with  pliers  at  the 
first  stake.  After  cutting  each 
individual  wire  the  crew,  con- 
sisting of  two  men  at  each 
end,  proceeded  at  once  to  fas- 
ten it  in  place  on  the  1-in. 
cable  which  had  been  previous- 
ly stretched,  to  remove  twists, 
and  laid  out  on  the  ground  in 
position  for  hoisting.  In  cut- 
ting the  wires,  1  ft.  over  and 
above  finished  dimensions  was 
allowed  for  connections. 

There  was  then  a  point  6  in. 
from  each  end  measured  off 
with  a  rule,  and  this  point  was 
kept  at  the  inner  side  of  the 
cable  while  the  end  of  the  wire 
was  given  two  turns  around  the 
cable  and  sufficient  wrapping  to 
secure  it.  The  antenna  as  a 
whole  reaches  the  corona  point 
with  an  undamped  high-fre- 
quency current  of  250  amperes 
at  a  frequency  of  20,000  cycles. 
The  accompanying  night  photo- 
graph, Fig.  3,  shows  a  layer  of 
the  antenna  at  the  corona  noint 
during  the  test  of  a  300  K.W. 
Federal-Poulsen  Arc  genera- 
tor. The  dummy  antenna  was 
used  at  the  laboratory  for  testing  the  high 
power  apparatus  which  the  company  has 
constructed  for  the  United  States  Navy  at 


WOMEN   RADIO   OPERATORS  TO 
THE  FRONT. 

The  National  League  for  Women's  Ser- 
vice has  enlisted  its  first  wireless  oper- 
ator. She  is  Miss  Helen  Campbell  and 
she  is  an  expert  in  receiving  and  sending. 
She  entered  the  service  of  the  League  on 
May  8th.  Women  in  all  parts  of  the  coun- 
try are  taking  up  the  study  of  telegraph 
and  radio  operating  in  earnest,  as  these 
vocations  hold  undeniable  promise  for  those 
aspiring  to  fill  positions  of  responsibility 


Miss  Helen 
I  ntricacies 
Send 


Campbell  Has  Successfully  Mastered  the 
of  Radio-Telegraphy.  She  Is  an  Expert  in 
ing  and    Receiving    Radio  Messages. 

and  service  to  the  Nation.  Besides,  there 
will  be  plenty  of  opportunities  after  the 
war   for  radio  and  telegraph  experts. 


188 


THE  ELECTRICAL  EXPERIMENTER 


July,  1917 


HOW  THE  GOVERNMENT  SEALS 
RADIO  APPARATUS. 

Uncle  Sam's  radio  inspectors  have  been 
extremely  busy  the  past  few  weeks  seal- 


Our  Uncle  Samuel  Seals  Up  Wireless  Apparat 
Does  the  Job.    A  Heavy  Wire  Is  Run  Thru  Al 
and  Sealed  as  Shown,  and  Woe  Be  Unto  Anyo 
Breaks  the  Seal. 

ing  up  all  radio  apparatus  not  in  actual 
use  by  the  Government. 

Heavy  wire  is  wrapt  around  the  poles 
of  the  spark  gap  and  the  ends  of  this 
wire  are  joined  with  wax  bearing  the  great 
seal  of  the  United  States  of  America. 
Heavy  prison  penalties  are  provided  for 
the  breakage  of  this  seal.  The  wire  short- 
circuits  the  spark  gap  and  makes  it  impos- 
sible to  secure  a  spark.  The  impression 
of  the  great  seal  is  made  in  red  wax  on 
an  ordinary  piece  of  paper. 


U.  S.  CALLS  FOR  TELEGRAPH  AND 
RADIO  OPERATORS. 

The  war's  demand  for  telegraphic  com- 
munication has  increased  so  much  that  an 
emergency  call  has  been 
issued  thru  the  War 
Department  for  young 
men  and  women  of  the 
country  to  present 
themselves  to  be  trained 
as  telegraph  operators. 
Arrangements  have 
been  made  with  the 
Western  Union  Tele- 
graph Company  to  train 
2,500  n  e  w  operators. 
These  are  to  enable  the 
Government  to  handle 
its  war  telegraph  busi- 
ness without  taking  any 
more  operators  for  the 
Signal  Corps  from  the 
present  railroad  and 
commercial  tele- 
graph  forces,  and  with- 
out seriously  interfer- 
ing with  vital  communi- 
cations. 

The  War  Depart- 
ment's appeal  fol- 
lows : — 

"Several  thousand 
young  men  and  women 
are  needed  for  tele- 
graph service,  either  in 
the  Signal  Corps  of  the 
army,  or  to  replace 
those  in  commercial 
work  who  are  leaving 
positions  to  join  the 
colors.    These  y  oting 
people  must  be  trained. 
For   this   purpose  the 
Western    Union  Tele- 
graph   Company  has 
placed  its  facilities  at 
us  Tight  When  He  the  disposal  of  the  Gov- 
I  the  Binding  Posts  eminent  to  tram  twen- 
ne  Who  Maliciously  ty-five    hundred  oper- 
ators, and  the  training 
will  be  conducted  by  its  experts. 

"It  is  estimated  that  there  are  more 
than  30,000  amateur  wireless  (sending) 
operators  in  the  Tjnited  States.  These 
young  men  now  have  an  opportunity — 
perhaps  the  only  opportunity  of  their  lives 
— to  contribute  materially  to  their  country's 
welfare  in  an  hour  of  need  by  volunteer- 
ing for  this  work.  At  the  same  time  they 
will  be  mastering  a  trade  in  which  stable 
employment  can  almost  always  be  secured 
in  any  important  city. 


"Telegraph  operators  in  the  army  and 
navy  occupy  preferred  positions  both  as 
to  rank  and  pay.  Young  men  who  take 
up  telegraphy,  but  who  do  not  enter  the 
Government  employ  will  still  render  pa- 
triotic service  by  relieving  those  who  de- 
sire to  enlist. 

"The  tremendous  demands  upon  the 
operating   forces   of   the   country  during 

A  HUMAN  RADIO  OUTFIT! 


Radio  Fiends  and  Bugs — 

Please  Take  Notice  of  the  Master  Incarnated 
Wireless  Vampire.  This  Photo,  Which  Came 
to  Us  Anonymous — by  Wireless  of  Course — 
Shows  How  the  Fiend  Is  Gradually  Turning 
into  a  Radio  Outfit.  His  Legs  Already  Are 
Long  Switch  Levers,  and  Before  We  Go  to 
Press,  His  Brain  Probably  Will  Have  Turned 
into  an  Ether  Wave!  Here  at  Last  We  Have 
a  Radio  Enthusiast  Who  Loves  His  Set  Well 
Enough  to  Get  Married  to  It! 


MANUFACTURING 
WIRELESS  APPARA- 
TUS FOR  SUBMA- 
RINE CHASERS. 

Radio  manufacturers  are 
now  working  night  and  day 
building  apparatus  for  the  U. 
S.  Naval  vessels.  The  photo 
shows  quenched  spark  gaps 
being  machined. 

These  spark  gaps  are  brass 
discs  with  silver  centers,  and 
they  must  be  accurate  to 
1/10.000  of  an  inch.  Measure- 
ment is  made  by  the  small 
dial  above  the  pin  which 
shows  the  accuracy.  If  the 
spark  gaps  are  inaccurate  they 
must  be  sent  back  to  be  ma- 
chined to  the  proper  dimen- 
sions. Sixteen  of  these  discs 
are  installed  in  each  set  for 
submarine  chasing  purposes. 


A  new  radio  station  has  re- 
cently been  erected  at  Viacha, 
near  La  Paz,  Bolivia.  Com- 
mercial service  was  estab- 
lished on  Oct.  20th. 


this  period  of  intense  activity — the 
mobilizing  of  all  the  resources  and  ener- 
gies of  the  American  people — have  taxed 
the  present  telegraph  forces  to  the  ut- 
most and  necessitate  the  immediate  re- 
cruiting of  hundreds  of  volunteers  for  this 
service.  The  Government  needs  telegraph 
operators  for  its  Signal  Corps. 

"Amateur  wireless  operators,  women 
typists,  and  all  other  competent  young 
men  and  women  possessing 
the  fundamentals  of  grammar 
and  high  school  education  and 
not  already  employed  in  service 
contributing  to  the  national  wel- 
fare, are  urged  to  apply  to  the 
offices  of  the  Western  Union 
Telegraph  Company  to  take  up 
telegraphy  training.  By  so  doing 
they  will  serye  their  country  in 
a  very  practical  and  patriotic 
way." 


Photo  by  Kadel  &  Herbert.  N.  Y 


Manufacturing  Quenched  Spark  Gaps  in  New  York  City  for  U.  S.  Naval 
Vessels.    The  Gap  Plates  Must  Be  Machined  to  1/10,000  inch  Accuracy. 


CORRECTION  NOTICE! 

In  the  article  appearing  in  the 
May  issue  and  entitled  "Receiv- 
ing the  Marconi  300  K.W.  Sta- 
tions on  the  Oscillating  Audion," 
by  S.  Curtis,  Jr.,  an  error  was 
made  in  stating  that  Dr.  White 
of  the  General  Electric  Com- 
pany's research  staff  had  suc- 
ceeded in  getting  an  Audion  type 
of  oscillator  to  operate  at  wave 
lengths  as  low  as  Yz  meter.  This 
should  have  read  6  meters,  which 
wave  length  of  oscillation  was 
only  obtained  with  a  perfect 
non-gaseous  bulb. 


July,  1917 


THE  ELECTRICAL  EXPERIMENTER 


189 


How  Radio  Brought  the  News  to  the  Farm 


WEATHER  reports,  market  quota- 
tions and  world  news  daily  by 
wireless  telegraph,  such  is  the 
innovation  which  makes  the  farm 
and  the  work  of  Archie  Banks, 
of  Delmar,  Iowa,  of  more  than  ordinary  in- 
terest. The  last  vestige  of  isolation  and 
aloofness  from  the  world  has  been  banished 
from  the  farm  by  this  young  Iowan.  Back 
of  his  achievements  lies  a  story  of  deter- 
mination which  should  be  an  inspiration  to 
all. 

Eight  years  ago  Archie  Banks  was  a  six- 
teen-year-old boy,  living  on  the  farm  of  his 
father,  a  well-known  live  stock  farmer.  The 
boy  had  always  been  interested  in  machin- 
ery and  mechanical  matters,  but  met  with 
little  encouragement  along  this  line  from 
his  parents.  He  might  never  have  had  an 
opportunity  to  develop  his  latent  talents  had 
it  not  been  for  an  accident.  One  day,  in 
working  about  her  household  task,  the  boy's 
mother  knocked  off  the  telephone  batteries. 

"Central  told  her  how  to  connect  them 
up  again  and  she  did  so,"  says  Mr.  Banks. 
"I  happened  to  come  in  then  and  she  told 
me  what  she  had  done.   Of  course,  I  wanted 
t©  see  if  she  did  it  right.    I  was  promptly 
told  to  run  along  and  that  what  I  knew  about 
telephone  batteries  wouldn't  bother  anyone. 
Well,  I  made  up  my  mind  I  would  know 
something  about  them,  and  I  set  to  work 
studying  everything  I  could  get  hold  of — 
books,  magazines 
and  catalogs.    In  a 
year    I    had  the 
house  wired  from 
cellar    to  garret, 
and    lighted  with 
electric  lights  run 
from  batteries. 
Two  years  after- 
ward I  had  a  small 
wireless  built,  but 
it  would  not  work 
well.    All  I  could 
do  was  to  talk  to 
Delmar,     a  mile 
away.      I  deter- 
mined to  do  better, 
and    so   I   set  to 
work  again." 

This  second  time 
the  boy  was  more 
successful,  so  that 
today  he  has  in- 
stall e  d  in  the 
twelve-room  farm- 
house, a  mile  from 
Delmar  and  about 
eight  miles  from 
Maquoketa,  a  com- 
plete wireless  tele- 
graph outfit,  by 
which  he  receives 
weather  forecasts 
and  news  bulletins 
wireless  station 


Farmers  who  live  near  Mr.  Banks  did  not 
have  to  wait  for  the  belated  newspaper 
which  the  R.  F.  D.  carrier  delivered  to  see 
what  the  weather  would  likely  be  the  next 
few  hours  ;  they  were  not  caught  unprepared 
by  any  sudden  and  unpredicted  change  in 
temperature;  a  minute  at  the  rural  tele- 
phone, to  secure  proper  connections  with 
the  Banks  farmhouse,  and  the  weather  fore- 
cast was  known  by  them  as  promptly  as  it 
was  known  by  the  man  in 
the  city,  with  the  daily 
paper  laid  on  his  desk  but 
a  few  minutes  after  it  had 
left  the  press. 

This  is  not  all,  however. 
As  one  drives  toward  or 
from  Delmar,  along  the 
road  which  leads  by  the 
Banks  home,  he  comes  sud- 
denly upon  a  large  sign 
stretched  across  the  road, 
a  board  sign  eight  feet  long 
and  two  feet  high,  upon 
which  is  painted,  in  large 
words,  this  placard  :  "Eat 
honey,  For  sale  here.  To- 
day's weather  report  by 
wireless  on  next  curve. 
Archie  Banks."  A  few  rods 
further  on,  at  the  first  turn 
in  the  road  stands  the  large 
bulletin  board,  eight  feet 


east  and  west.  Passers-by  who  would  stop 
at  the  Banks'  home  to  read  the  bulletin 
board,  or  to  inspect  the  wireless  plant, 
bought  honey  and  thus  came  to  be  regular 
customers  of  the  apiary,  adding  to  a  side- 
line income,  which  has  already  begun  to  as- 
sume large  proportions.  There  was  no 
thought  of  the  business  possibilities  of  his 
wireless  service  when  it  was  first  inaugu- 
rated, but  there  is  a  close  connection  be- 


Now  That  the  Country  Is  in  a  State  of  War  and  All  Amateur 
Radio  Stations  Are  Closed,  Mr.  Archie  Banks,  Owner  of  the 
Elaborate  Wireless  Station  Here  Pictured,  Has  Offered  His  Sta- 
tion and  Services  to  Uncle  Sam.  Before  the  War  He  Used  to 
Receive  the  Daily  Weather  Reports  and  Other  News.  Which  Was 
Posted  on  a  Bulletin  Board  in  His  Home  Town — Delmar,  Iowa. 


twice  a  day  from  the 
connected  with  the  Illinois 
State  Agricultural  College,  at  Springfield, 
and  the  Iowa  State  Agricultural  College,  at 
Ames.  (Prior  to  the  war  of  course). 
Weather  reports  are  sent  out  by  these  sta- 
tions every  day  at  noon,  while  news  bulle- 
tins and  the  events  of  the  world  are  sent 
twice  a  day — at  noon  and  again  at  8 :30  in 
the  evening. 

But  Mr.  Banks  did  not  stop  with  this. 
He  did  not  believe  in  being  selfish.  He  had 
this  news  service  himself;  why  not  share 
it  with  friends,  neighbors  and  passers-by? 
Accordingly,  the  weather  forecasts  and  the 
news  bulletin  were  telephoned  from  his 
farmhouse  to  whoever  desired  to  receive 
them,  the  climatic  changes  being  known  for 
a  radius  of  ten  or  fifteen  miles,  long  in  ad- 
vance, by  means  of  this  excellent  service. 


high  by  five  feet  broad.  Upon  it  Mr.  Banks 
used  to  post  the  weather  forecasts  and  the 
news  bulletin,  each  day,  just  as  soon  as  they 
were  received.  Whoever  drove  by  the  Banks' 
home  got  the  news  of  the  world  as  prompt- 
ly and  as  accurately  as  the  city  man  got  it 
from  reading  the  bulletin  board  of  the 
metropolitan  newspaper  office. 

All  this  is  not  without  its  business  effect. 
Mr.  Banks  (now  twenty-four  years  of  age 
and  farming  for  himself)  owns  and  operates 
a  farm  of  160  acres,  carrying  on  a  general 
farming  business.  He  has  two  particular 
hobbies,  however — electricity  and  bees.  Prior 
to  December  10,  he  had  sold  almost  3,000 
pounds  of  honey  last  year;  he  could  sell 
much  more  if  he  had  it,  for  his  honey  is  of 
good,  uniform  quality,  and  Delmar  is  in 
the  midst  of  a  rich  honey  section,  many  car- 
loads being  shipt  from  there  to  all  points 


tween  the  two,  without  a  shade  of  doubt. 

Nor  must  it  be  thought  that  Archie  Banks 
is  not  a  genuine  farmer ;  he  is  in  love  today 
with  farm  life  and  with  the  beautiful  farm 
which  he  bought  of  his  father,  with  the  big 
twelve-room  house  set  in  its  grove  of  maples 
and  elms  100  feet  back  from  the  road,  with 
one  room  given  over  to  the  wireless  outfit,, 
which  brings  that  particular  farm  into  touch 
with  all  the  outside  world. 

"The  wireless  station  is  about  as  com- 
plete as  I  can  make  it,"  says  Mr.  Banks.  "I 
have  copied  messages  from  Darien,  Pana- 
ma; Hanover,  Germany;  Mare  Island,  and 
San  Diego,  California  ; .  Guantanamo  Bay, 
Cuba;  Arlington,  Virginia;  New  York  City, 
and  all  over  the  world.  I  received  New 
York  messages  so  loud  that  the  signals  could 
be  heard  all  over  my  house,  which  is  of 
twelve  rooms." 


190 


THE  ELECTRICAL  EXPERIMENTER 


July,  1917 


Wireless  on  the  American  Submarine  Chasers 

By  SAMUEL  COHEN 


THE  greatest  task  of  the  United 
States  in  the  war  against  Germany  is 
that  in  overcoming  the  under-sea 
monsters,  the  SUBMARINES,  which 
have  proven  to  be  a  constant  and 
rapidly  increasing  menace  to  both  the  Allied 
and  American  shipping. 


transmitting  set  is  seen  on  the  right  and  the 
apparatus  comprising  the  installation  con- 
sists of  the  following  and  all  of  which  are 
mounted  on  a  Bakelite  panel.  The  source 
of  high  tension  current  for  charging  the 
condenser  is  derived  from  a  special  spark 
coil,  stationed  behind  the  panel.    An  inde- 


• 

• 

• 

• 

• 

1 

• 

h 

Q    «  ©  a  (§ 


Fig.  1 — Space  Is  at  a  Premium  on  the  "Submari 
Is  Available  the  Extremely  Light- Weight  Tran 
Utilizes  a  Spark  Coil  with  Indepe 


ne  Chaser."  For  Such  Radio  Service  There 
smitting  and  Receiving  Set  Illustrated.  It 
ndent  Vibrator  for  Batteries. 


This  problem  is  now  in  the  hands  of  our 
most  prominent  scientists,  inventors  and 
marine  experts,  and  one  solution  to  this  task 
seems  to  have  been  found  in  the  building  of 
hundreds  or  even  thousands  of  high-speed 
armed  motor-boats  to  be  used  in  fighting 
the  U-boats. 

One  of  the  most  important  details  in 
equipping  these  "submarine  chasers"  is  that 
of  radio-communication  apparatus  to  be 
used  for  notifying  near-by  vessels  of  sub- 
marine attacks  and  the  like.  The  marked 
development  in  the  art  of  radio-telegraphy 
in  recent  years  has  demonstrated  that  every 
vessel  to  be  used  for  the  above  named  work 
should  and  can  be  equipt  with  a  suitable 
light-weight,  yet  highly  efficient  radio  trans- 
mitting and  receiving  outfit. 

A  considerable  variety  of  such  apparatus 
have  already  been  designed  and  built  and 
we  give  below  descriptions  of  several  types 
of  transmitting  and  receiving  sets  which 
will  prove  very  effective  for  the  work  in 
question.  The  accommodations  offered  by 
submarine  chasers,  are  few  and  for  this  rea- 
son the  radio  engineer  must  comply  with  the 
accommodations  as  much  as  possible  before 
he  undertakes  the  designing  of  the  equip- 
ment. Space  is  a  very  important  factor  in 
consideration,  and  for  this  reason  the  ap- 
paratus herewith  described  have  been  chosen 
since  they  are  of  the  most  compact  type  ever 
built  for  the  efficiency  which  they  have 
shown. 

The  first  of  these  outfits  is  illustrated  at 
Fig.  1.  This  set  was  designed  and  built  bv 
Mr.  A.  B.  Cole,  of  New  York  City.  The 


pendent  vibrator  is  employed  and  this  is 
mounted  on  the  panel,  and  may  be  seen  di- 
rectly to  the  left  of  the  antenna  switch, 
which  is  the  right  circular  knob.  A  number 
of  important  features  are  incorporated  in 
this  independent  vibrator,  vie.,  a  high-tone, 
corresponding  to  a  500  cycle  generator,  is 


obtained  with  a  primary  excitation  of  6 
volts,  obtained  from  a  storage  battery.  The 
current  consumed  by  the  primary  of  the 
spark  coil  is  indicated  by  the  two  lower 
meters ;  the  one  toward  the  left  indicates 
amperes,  and  the  one  toward  the  right, 
volts.  The  simple-pole  double-throw  switch 
below  the  two  meters  is  used  to  throw  in 
either  6  or  12  volts  onto  the  primary  of  the 
coil-;  the  latter  voltage  must  naturally  be 
derived  from  a  12  volt  battery  or  other  gen- 
erating source.  Terminals  for  the  current 
source  are  located  below  the  switch.  The 
plug  towards  the  right  interconnects  a  key 
with  the  coil  as  perceived ;  while  the  plug 
on  the  left  is  employed  for  connecting  the 
receiving  apparatus  with  the  antenna  and 
ground,  thru  the  change-over  switch  which 
is  located  directly  over  the  voltmeter. 

The  oscillatory  circuit  of  the  equipment 
consists  of  the  secondary  of  the  induction 
coil  generating  the  high  tension  voltage 
which  is  used  to  charge  a  moulded  type  con- 
denser, thru  an  inductance  and  a  quenched 
gap  discharger,  the  latter  being  visible  in 
the  center.  Annular  grooves  are  cut  on  the 
surface  of  the  outside  plate  for  rendering 
greater  cooling  facilities  to  the  gap.  A 
radiation  ammeter  is  also  furnished  and  this 
is  placed  on  top  of  the  panel. 

The  receiving  equipment  consists  of  a 
standard  cabinet  outfit,  with  crystal  de- 
tector which  can  be  seen  to  the  left  of 
the  transmitting  panel.  It  is  comprised  of 
an  inductively  coupled  tuner  which  has  a 
fixt  coupling  coil,  linked  with  a  variable 
capacity  for  tuning  to  different  wave  lengths. 
This  condenser  is  mounted  in  the  center. 
A  short  and  long  wave  change-over  switch 
is  employed  and  this  is  placed  at  the  center 
upper  corner.  The  detector  is  of  the  mineral 
type  and  is  mounted  below  the  condenser, 
while  the  buzzer,  for  test  work  is  just  be- 
low the  detector. 

The  complete  outfit  has  been  found  to  be 
very  satisfactory  and  efficient  and  it  will  no 
doubt  prove  to  be  highly  serviceable  to 
Uncle  Sam's  mosquito  fleet. 

In  addition  to  the  excellent  transmitter 
above  described  a  very  efficient  and  an  all- 
around  receiving  outfit  has  been  designed 
and  built  by  Messrs.  L.  G.  Pacent  and  A.  H. 
Grebe  for  the  submarine  chasers,  and  this 
outfit  is  illustrated  in  Fig.  2.  This  equip- 
ment consists  of  four  units,  viz.,  a  main 
tuning   cabinet,    loading   cabinet,  detector 


Fig.  2 — An  Excellent  Audion  Type  Radio  Receptor  for  "Mosquito  Fleet"  Service. 

It  Is  Fitted  with  "Radiumized"  Dials  That  Glow  in  the  Dark. 


July,  1917 


THE  ELECTRICAL  EXPERIMENTER 


191 


cabinet,  and  an  emergency  crystal  detector. 
The  main  tuning  cabinet  is  the  largest  of 
the  three  and  comprises  an  inductive  coup- 
ler, coupled  with  variometers,  the  latter  of 
which  are  controlled  by  two  handles,  while 
the  center  one  operates  a  variable  condenser 
linked  in  the  secondary  circuit.  The  handle 
on  the  left  side  is  used  to  control  the  sec- 
ondary coupling.  The  two-point  switches 
are  employed  for  regulating  the  inductance 
of  the  primary  of  the  inductive  coupler. 

The  cabinet  on  top  of  this  is  the  loading 
box  which  contains  the  proper  coils  for  aid- 
ing the  regenerative  Audion  circuit ;  the 
center  knob  is  the  coupling  handle,  while 
the  two  side  knobs  are  the  inductance  con- 
trol handles.  The  cabinet  to  the  right  is  the 
detector  box  in  which  the  vacuum  detector 
is  housed.  An  opening  litted  with  a  sliding 
door  is  used  to  note  the  illumination  bril- 
liancy of  the  detector  bulb.  The  switch  to 
the  right  is  the  filament  switch  while  the  one 
to  the  left  is  the  "B"  battery  control  switch. 
A  variable  resistance  is  secured  to  the  side 
of  this  cabinet  (not  shown  here)  and  this  is 
used  for  regulating  the  current  consumption 
of  the  filament.  The  emergency  crystal  de- 
tector is  hooked  up  to  the  set  thru  binding 
posts  at  the  bottom  of  the  main  tuning  cab- 
inet. 

One  of  the  most  striking  characteristics 
of  this  receiving  outfit  is  that  which  has 
been  overlooked  by  all  of  our  radio  en- 
gineers designing  apparatus  intended  for 
warfare  purposes.  This  is  the  application 
of  the  wonderful  properties  possest  by 
radium  of  giving  forth  light  when  mixed 
with  certain  phosphorescent  materials.  All 
of  the  graduated  dials  of  this  equipment 
are  painted  with  phosphorescent  radium 
paint  which  glows  in  the  dark,  and  which 
facilitates  working  operations  of  the  oper- 
ator when  he  is  ordered  to  have  his  den 
pitch  dark  during  certain  engagements  in 
war.  This  will  certainly  be  appreciated  by 
the  radio  operator  who  has  to  operate  this 
receiving  set.  All  connections  of  the  vari- 
ous pieces  of  apparatus  are  made  bv  means 
of  square  shaped  aluminum  wire  which  has 
been  found  to  be  very  effective  for  wiring 
purposes,  as  it  is  easier  to  wire  and  at  the 
same  time  gives  a  better  appearance  to  the 
finished  instrument.  It  also  reduces  the 
weight. 

The  illustration,  Fig.  3,  shows  a  well- 
built  set  designed  by  Cutting  and  Washing- 
ton. This  outfit  utilizes  a  new  principle  in 
radio  transmitter  design  involving  the  use 
of  a  special  spark  gap,  by  means  of  which 
powerful  oscillations  and  a  hy-note  signal 
are  produced  in  a  very  simple  manner  with- 
out a  transformer.  The  antenna  wave 
length  can  be  changed  with  this  set  by  alter- 
ing the  secondary  of  the  oscillation  trans- 
former only,  the  primary  remaining  fixt. 


A  Medal  of  Honor  to  be  Awarded  by  the  Insti- 
tute of  Radio  Engineers 


The  Board  of  Direction  of  the  Institute 
of  Radio  Engineers  has  decided  to  award 
annually  a  "M  e  d  a  1  of  Hono  r"  to 
such  persons  who  have  distinguished  them- 


recognized  standing  and  must  be  in  actual, 
tho  not  necessarily  commercial,  operation. 
However,  preference  is  to  be  given  to 
widely  used  and  widely  useful  inventions. 


New  "Medal  of  Honor"  to  be  Presented  by  the  Institute  of  Radio  Engineers  Each  Year  to  the 
Person  Who,  During  the  Two  Preceding  Calendar  Years,  Shall  Have  Made  Public  the  Greatest 
Advance  in  the  Art  of  Radio-Communication. 


Fig.   3— Particularly    Efficient    Radio  Set 
"Mosquito  Fleet"  Service 


selves  by  unusual  advances  in  the  fields  of 
radio-telegraphy  and  telephony.  It  has 
been  felt  that  some  way  should  be  found 
whereby  valuable  work  in  these  fields  of 
great  and  rapidly  growing  importance 
might  properly  he  recognized  by  an  au- 
thoritative engineering  society.  As  is  well 
known,  the  Institute  of  Radio  Engineers, 
with  more  than  1.000  members  here  and 
abroad,  and  with  sections  in  New  York, 
Washington,  Boston,  Seattle,  San  Fran- 
cisco (with  others  in  contemplation),  is 
the  leading  technical  and  scientific  society 
in  the  wireless  field.  It  is  therefore  rec- 
ognized that  a  "Medal  of  Honor"  from 
the  Institute  will  be  a  goal  worthy  of  at- 
tainment by  any  investigator. 

The  appearance  of  the  medal  is  as  fol- 
lows :  The  front  is  a  symbolic  represen- 
tation of  ■electromagnetic  waves,  indicating 
the  interlinking  of  the  magnetic  and  elec- 
tric forces  in  their  rapid  path  thru  the 
depths  of  space.  The  reverse  side  bears 
the  inscription : 

"To  

in  Recognition  of  Distin- 
guished Service  in  Radio 
Communication"  (followed 
by  the  date),  the  inscription 
being  surrounded  by  a  lau- 
rel wreath. 

The  medal  is  the  work  of 
the  well-known  sculptor, 
Edward  Sanford,  Jr.,  of 
New  York. 

The  award  will  be  made 
yearly  at  the  April  meeting 
of  the  Institute  to  the  per- 
son who,  d  u  r  i  n  g  the  two 
preceding  calendar  years, 
shall  have  made  public  the 
greatest  advance  in  the 
art  of  radio-communication. 
The  advance  may  be  a 
patented  or  unpatented  in- 
vention, but  it  must  lie  com- 
pletely and  adequately  de- 
Well  Adapted  to  scribed  in  a  scientific  or 
engineering   publication  of 


The  advance  may  also  consist  in  a  scien- 
tific analysis  or  explanation  of  hitherto 
unexplained  phenomena  of  distinct  import- 
ance to  the  radio  art,  altho  the  application 
may  not  be  immediate.  Preference  will  be 
given  to  analyses  directly  applicable  in  the 
art.  In  this  case  also  publication  must  be 
full  and  in  approved  form. 

The  advance,  furthermore,  may  consist 
in  a  new  system  of  traffic  regulation  or 
control,  a  new  system  of  administration 
of  radio  companies  or  the  radio  service 
of  steamship,  railroad  or  other  companies, 
a  legislative  programme  beneficial  to  the 
radio  art,  or  any  portion  of  the  operating 
or  regulating  features  of  wireless.  It  must 
be  described  publicly  in  clear  and  approved 
form  and  must,  in  general,  be  actually 
adopted  in  practise.  In  all  cases,  marked 
preference  is  to  be  given  to  advances  made 
in  the  preceding  year. 

The  medal  is  to  be  awarded  under  the 
following  conditions  : 

At  least  thirty  days  before  the  April 
meeting  the  Board  of  Direction  will  call 
from  a  number  of  members  and  fellows 
of  the  Institute,  whom  it  may  choose  to 
consult,  for  suggested  candidates.  This 
provision  will  be  waived  wholly  or  in  part 
for  1917  only. 

In  deciding  upon  the  award,  the  Board 
at  its  April  meeting,  thru  those  actually 
present  or  voting  by  mail,  will  nominate 
at  least  one,  but  not  more  than  three  can- 
didates, in  order  of  preference  for  the 
award.  The  names  of  these  candidates  will 
then  be  sent  to  each  member  of  the  board, 
who  will  have  the  privilege  of  returning 
a  vote  for  one  candidate.  Four  weeks  after 
the  April  meeting  the  ballot  will  be  read, 
and  the  candidate  receiving  the  most  votes 
will  become  the  recipient  of  the  award. 

The  official  presentation  of  the  medal 
to  the  successful  candidate  or  his  repre- 
sentative will  occur  at  the  May  or  June 
meeting. 


AMATEURS  ! 
ATTENTION!! 


Now  that  we  are  for  the  time 
being,  deprived  of  using  our 
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The  army  and  navy  need  thou- 
sands of  operators  right  now. 
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The  outfit  replaces  the  old-fashioned  learne 
Radiotone  Codegraph  comprises  our  famous 
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not  harsh,  is  heard  all  over  the  room.  With 
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AND  THAT  IS  NOT  ALL: 

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with  a  brilliant  electric  light. 
Just  insert  Flag  in  button- 
hole of  your  coat,  put  flash- 
light case  in  vest  or  coat 
pocket  and  every  time  you 
press  the  button,  the  flag  in 
your  button-hole  flashes  up 
with  a  beautiful  color  effect. 


Illuminated  flag,  cord  and  plug  (to      <t  CQ      (postage  10 
be  connected  to  any  2  cell  flashlight ) ,  cents). 
Illuminated  flag,  flashlight  case  and  battery,  cord  and  plug, 

complete  as  per  illustration,  $1.10  postage  15c). 
DEALERS  :  Write  for  our  proposition  today. 

IMMEDIATE  SHIPMENTS 


THE  "ELECTRO  TELEGRAPH" 


TELEGRAPH  CODES. 


LETTERS       MORSE        I  CONTINENTAL 


$122 


Electro  " 
telegraph 


is  not  a  toy,  but  a  practical,  honestly  built  telegraph  outfit,  which  not  only 
sounds  but  works  like  the  big  commercial  instruments.  By  studying  the 
code  for  30  davs  vou  can  become  a  first-class  telegraph  operator,  bucii 
operators  are  in  big  demand  now.  Outfit  consists  of  TWO  complete  tele- 
graph instruments  each  measuring  3  y2  x2  V2  x2  % .  All  metal  parts  are 
highly  nickel  plated,  including  key  lever.  Note  hard  rubber  knob.  Tele- 
graph Code  Chart,  telegraph  blanks  and  connecting  wire  comes  with  set, 
but  no  batteries.  Outfit  works  on  2  dry  cells  (one  cell  for  each  instru- 
ment). The  "Electro"  is  the  ONLY  Outfit  that  works  both  ways,  each 
station  can  call:  no  switches,  no  extras.  Nothing  to  get  out  of  order. 
Guaranteed  to  please  you  or  money  back.  <M  QQ 

Price  Complete  as  illustrated   v  ' 

At  all  good  dealers  and  department  stores.  If  your  dealer  cannot 
supply  you  send  us  $1.00  for  outfit  and  add  mailing  charges  for  two 
pounds,  otherwise  we  ship  express  collect. 


THE  ELECTRO  IMPORTING  CO. 


No.  H!<  1800 

The  "Electro"  Radiotone 

HIGH    FREQUENCY   SILENT   TEST  BUZZER 

The  RADIOTONE  is  NOT  a  mere  test  buzzer, 
it  is  infinitely  more.  Mr.  H.  Gernsljack  who  de- 
signed this  instrument  labored  incessantly  to 
produce  an  instrument  which  would  imitate  the 
sound  of  a  high  power  Wireless  station  as  heard 
in  a  set  of  phones.  This  actually  has  been 
achieved  in  the  RADIOTONE.  This  instrument 
gives  a  wonderful  high  pitched  MUSICAL  NOTE 
in  the  receivers,  impossible  to  obtain  with  the 
ordinary  test  buzzer.  The  RADIOTONE  is  built 
along  entirely  new  lines;  it  is  NOT  an  ordinary 
buzzer,  reconstructed  in  some  manner.  The 
RADIOTONE  has  a  single  fine  steel  reed  vibrat- 
ing at  a  remarkably  high  speed,  adjusted  to  its 
most  efficient  frequency  at  the  factory.  Hard 
silver  contacts  are  used  to  make  the  instrument 
last  practically  forever. 

Yes,  the  RADIOTONE  is  SILENT.  In  fact, 
it  is  so  silent  that  you  must  place  your  ear  on 
top  of  it  to  hear  its  beautiful  musical  note. 

You  will  be  astounded  at  the  wonderfully  clear, 
500  cycle  note,  sounding  sharply  in  your  re- 
ceivers, when  operated  on  one  dry  cell.  To  learn 
the  codes,  there  is  absolutely  nothing  like  it. 
With  the  radiotone,  a  key  and  one  dry  cell  and 
ANY  telephone,  a  fine  learner's  set  is  had.  Two 
or  more  such  sets  in  series  will  afford  no  end  of 
pleasure  for  intercommunication  work.  Particu- 
larly now  that  we  cannot  use  our  Wireless  sets, 
the  Radiotone  is  already  in  wonderful  demand. 
All  the  interesting  things  as  described  with  our 
Radiotone  Codegraph,  elsewhere  on  this  page, 
can  be  performed  with  the  Radiotone,  a  key,  a 
dry  cell  and  a  phone. 

Radiotone  as  described  each  ^.90 

IMMEDIATE  SHIPMENTS 


HERCULES  DYNAMO 

The  Electro 
Hercules  is  a 
dynamo  gener- 
ating 12  Volts,  9 
Amperes  (100 
Watts>  and  a 
marvel  of  elec- 
trical or  me- 
chanical effi- 
ciency and  sim- 
plicity. 

It  is  espe- 
cially designed  for  lighting  and  charging  storage 
batteries;  will  run  18  twelve  volt  lamps  simul- 
taneously. Can  also  be  used  as  a  powerful  mo- 
tor developing  nearly  %  H.P.  Machine  is  shunt 
wound;  size  7  in.  high,  by  11%  in.  long  and 
6%  in.  wide.  It  is  the  cheapest  Dynamo  for  its 
output  on  the  market. 

No.  AGEK  1209.  Electric  Hercules  Dy-fl-1  "7  CH 

namo  ;  shipping  weight,  40  lbs.  Price. . .  .M*1  • 

We  carry  these  machines  always  in  stock  and 
can  make  immediate  shipment. 


The  "Electro"  Rheostat-Regulator 

(Porcelain  Base) 

This  illustration  represents  our  little  current 
regulator  which  is  used  everywhere  to  regulate 
battery  current.  It  will  prevent  the  burning  out 
of  your  battery  lamps,  or  will  regulate  the  speed 
of  your  small  motors,  and  scores  of  other  uses. 

It  makes  an  excellent  automobile  lamp  dimmer, 
where  it  can  be  used  to  cut  down  the  glare  of  the 
headlights.  This  little  instrument  is  impossible 
In  gel  out  of  order.  It  is  constructed  ENTIRELY 
OF  PORCELAIN,  metal  and  hard  rubber. 

The  resistance  of  our  Rheostat  is  10  ohms,  the 
capacity  3  amperes  continually,  size  is  4  inches  in 
diameter;  thickness  of  porcelain  base  is  13/16  ins. 
No.  FK5000    Rheostat.  Regulator.  Price 
Shipping  weight,  2  lbs. 
IMMEDIATE  SHIPMENTS 


$.60 


Fl<  5000 


"Electro"  Pony  Receiver 


Our  Pony  receiver  is 
without  doubt  the  best 
article  for  the  money 
to-day. 

Points  of  superiority  : 
Hard  rubber  composi- 
tion shell  beautifully 
polished.  Powerful  per- 
manent steel  magnet, 
soft  iron  core,  fibre  coil 
heads,  very  thin  dia- 
phragm, brass  posts  in- 
side. Hanger  can  be  un- 
screwed and  receiver 
will  then  fit  our  No. 
AX8077  headbands. 

SOME  USES. —  For 
all  telephone  work. 
Also  for  making  the 
small  testing  outfits  for 
cuit  with  only  one  dry  cell  or  flashlight  bat- 
tery. When  connected  in  parallel  with  your 
house  telephone  receiver,  you  have  a  double 
receiver,  an  invaluable  acquisition  to  those 
who  phone  in  noisy  places  or  to  people  hard 
of  hearing.  It  can  also  he  used  for  wireless 
though  its  low  resistance  won't  permit  of 
such  good  results  as  a  higher  resistance 
phone. 

This  receiver  is  single  pole;  2I4xl'/s  inches:  wgt. 
4  oz. ;  resistance.  75  ohms.  IF  TWO  OF  THESE 
RECEIVERS  ARE  rSEO.  IT  IS  POSSIBLE  TO 
SPEAK  AT  A  DISTANCE  OF  130  FEET  WITH- 
OUT USING  BATTERIES.  ONE  WIRE  BEING 
SUFFICIENT  IF  GROUND  IS  USED.  ttft  en 
No.  EKI024   Pony  Receiver.  75  ohms  <pU.OU 

IMMEDIATE  SHIPMENTS 


El<  1024 


repair  men 


cir- 


BINDING  POSTS 


No.    B-~  Weight  Weight  Weight  Weight  J>0.  u  / 

Each  $0.15  1  lb.  per  12.  1  lb.  per  12.        1  lb.  per  12.       1  lb.  per  12.         Each  $0.10 

Shipping  Shipping 
Weight  IMMEDIATE  SHIPMENTS  Weight 

2  lbs.  per  doz.  2  lbs.  per  12. 

These  binding  posts  are  furnished  either  nickel  plated  or  gold  lacquered.  They  are  made 
of  first  quality  brass  ;  holes  are  accurately  bored,  well  fitting  set  screws,  and  highly  polished. 
Each  post  is  furnished  with  a  %,  in.  machine  screw  and  washer  (not  shown  in  illustrations). 
Engravings  are  full  size. 

"The  Livest  Catalog  in  America" 

Our  big,  new  electrical  cyclopedia  No.  18  is  waiting  for 
you.    Positively  the  most  complete  Wireless  and  elec- 
trical catalog  in  print  today.     200  Big  Pages,  600 
illustrations,  500  instruments  and   apparatus,  etc. 
Big  "Treatise  on  Wireless  Telegraphy."    20  FREE 
coupons  for  your  100-page  FREE  Wireless  Course 
in  20  lessons.    FREE  Cyclopedia  No.  18  measures 
7x5%".    Weight  %  lb.    Beautiful  stiff  covers. 


"THE  LIVEST  CATALOG 


AMERICA" 


Now  before  you  turn  this  page  write  your 
name  and  address  on  margin  below,  cut  or 
tear  out,  enclose  6  cts.  stamps  to  cover 
mail    charges,    and    the    Cyclopedia  is 
yours  by  return  mail. 


THE  ELECTRO  IMPORTING  CO 
231  Fulton  Street,  New  York  City, 


FULTON  ST.,  NEW  YORK,  N.Y. 


AMATEURS  ! 
ATTENTION!! 


Now  that  we  are  for  the  time 
being,  deprived  of  using  our 
Radio  outfits,  it  behooves  us  to 
become  proficient  in  learning 
the  Wireless  Codes.  Operators 
who  know  the  Code  are,  and 
will  be,  In  ever  rising  demand. 
The  army  and  navy  need  thou- 
sands of  operators  right  now. 
the  required   speed,  when  your  country 

The  Radiotone  Codegraph  is  positively  the  only  instrument  made  that  will  send  such 
an  unbelievably  close  imitation  of  a  high  pitch  Radio  Station,  that  It  bas  baffled  experts. 
The  outfit  replaces  the  old-fashioned  learner's  outfit,  consisting  of  key  and  sounder.  The 
Radiotone  Codegraph  comprises  our  famous  Radiotone  High  Frequency  Silent  Buzzer,  a 
special  loud  talkinp  receiver  with  horn,  and  a  key  all  mounted  on  a  base.  Operated  on 
one  or  two  drv  cells,  the  phone  will  emit  the  characteristic  high  pitch  sound,  which  while 
not  harsh,  is  heard  all  over  the  room.  With  little  trouble  you  can  learn  the  code  correctly 
in  30  days— 


AND  THAT  IS  NOT  ALL: 


Connect  two  of  these  outfits  together 
friend  five  or  fifteen  blocks  distant  can  coi 
will  see  it.  Or  vou  can  use  instead  of  the  ' 
■  110  lighting  I 


directions  how  to  do  this  are  furnished  with  the  instrument. 
Century  instrument  that  will  sell  like  WILDFIRE.   600  sold  i 
our  proposition  today! 

Radiotone  Codegraph  complete  as  described,  ea> 
IMMEDIATE  SHIPMENTS 


ntprcnmmunication  work  and  vou  and  your 
le  over  a  NO.  36  WIRE,  so  fine  that  no  one 
a  metallic  fence  and  the  ground.  Or  you 
sing  no  extra  wire,  only  the  ground.  Full 


$1.95 


Selenium  Cells 

Ererybndy  has  rend  ,-ilioui 
!he  experiments  of  telepho- 
iograpby  (s  e  n  d  1  n  g  photi.- 
;raphs  over  a  wlro  hundreds 
.f  miles)   made  by  rrofcssoi 


portant  role.    At  present  wt 

1'nlted  States  sell  Inn  thes! 
cells.    They  are  the  most  sen- 

Better  send  for  a  cell  to- 
y  and  try  making  an  elec- 
tric dog  that  will  follow  ,i 
electric    I  'ir.'!  ir 


ind  | 


i  Hon 


her.    1916,  Iss 
No.    FX5I7     Selenium  Cell, 

$6.00 

M MEDIATE  SHIPMENTS 


BOYS! 


National 
rlglnal  colors 
electric  light. 
Just  Insert  Flap,  in  button- 
hole of  your  coat,  put  flash- 
light case  tn  vest  or  coal 
pocket 

press  the  button,  the  flap,  in 
your  button-bole   flashes  up 
beautiful  color  eHect- 


llluminated  flag,  flashlight 

complete  as  per  illustration.  $1.10  postage  lie). 
DEALERS  :  Write  for  our  proposill.m  today 
IMMEDIATE  SHIPMENTS 


nd  battery,  cord  and  plug 


THE 


TELEGRAPH  CODES. 


ELECTRO  TELEGRAPH 

$122 


siniiMh  liiit  mirks  like  Ihi'  Mj.' 

code  for  31)  days  you  can  hec< 

•>|icratiirs  are  In  Mi;  demand  n 
irrapli  Instruments  ■■.nil  rm  asi 
hlchlv  nickel  Mutcil.  ineluillne. 
L'r:i[ili  dale  Chart,  tcl'/tra  |>h  I' 
luil  no  liiitti-rlcs.  outll r  »,,rks 
mcnt).  The  "Electro"  Is  the 
Gallon  ran  call  ;  nu  snitches 
lamr.ml.e.l  tr,  i,|ea>e  vnu  nr  m< 
Price 


By  studying  t 
legraph  operator.  Such 
i  of  TWO  complete  leli- 
.    All  metal  parts  ara 
ard  rubber  knob.  Tele- 

ne  roll  fnr  each  instru- 
works  both  ways,  each 
nu  to  net  out  of  order. 

 $1.00 


THE  ELECTRO  IMPORTING  CO. 


Pa-tents; 

^0.842.550 

'  Feb5  1907 
J  Oct  £7, 1 908 

Feb  1. 1910 
No.  951.766 

Nq9(^I,655 
June^l.1910 

No.976,999 
Dec  10, 1910 

No  386,456 

No  988,767 
April  4,191 1 

No  1,010,138 
dan  30. 19lg. 

No  1033,035 
1  MyZ5.\3\Z 

No  \fj51filQ 
April  1. 1913 

'No  [\l  4,413 
dan  1915 

No  94,990 
;danRO.I9l4 

Pencingio 


E.  I.  Co. 
Patents 


The  "Electro"  Radiotone 

HIGH    FREQUENCY    SILENT    TEST  BUZZER 

Tho  RADIOTONE  Is  NOT  a  mere  test  buzzer. 
It  Is  infinitely  mure.  Mr.  H.  Ccrnsback  who  de- 
signed this  instrument  bin, ml  Incessantly  to 
produce  an  Instrument  villi. Ii  umihl  Imitate  the 
sound  of  a  high  pi.iier  Wirek-s  station  as  heard 
in  a  set  of  plumes.  Tills  actuallv  has  been 
achieved  In  the  HAIUOTIINK  This  instrument 
gives  a  wonderful  bleb  pitched  MUSICAL  NOTE 
In  tho  receivers.  1  m  puss  Idle  tu  nbtaln  with  tho 
ordinary  test  huzier  The  HADItVTONE  Is  built 
alone  entirely  new  lines  ;  It  Is  NOT  an  ordinary 
buzzer,    reconstructed    in    some    manner.  The 

RADIOTONE  lias  ..  single  tin,-  steel  reed  ill. rat- 
ine at  a  remarkably  hle.li  speed,  adjusted  to  Its 
most  efficient  frequency  at  the  factory.  Hard 
silver  contacts  arc  used  to  make  the  Instrument 
last  practically  forever. 

Tes,  the  RADIOTONE  Is  SILENT.  In  fact, 
it  Is  so  silent  that  you  must  place  your  ear  on 
top  of  It  to  hear  Its  beautiful  musical  note. 

You  will  be  astounded  at  the  wonderfully  clear, 
500  cycle  note,  guimdlng  sharply  In  your  re- 
ceivers, when  operated  on   ■  dry  cell.  To  learn 

the  codes,  there  is  absolutely  nothing  like  it. 
With  the  radiotone.  a  key  and  one  dry  cell  and 
ANY  telephone,  a  flue  learner's  set  is  had.  Two 
or  more  such  sets  In  series  will  alTord  no  end  of 
work.  Part  leu* 
inot  use  our  Wireless  sets, 
ady  In  wonderful  demand. 


$.90 


HERCULES  DYNAMO 


atlngl2  Yolts,  0 
Amperes  (111  II 
Wattaj  and  n 
marvel  of  elec- 
trical or  me- 
chanical effi- 
ciency and  sim- 
plicity. 

It    Is  espe- 
cially designed  for  llgbti 
batteries;  will  run  IS  t< 


1  charging  storage 
volt  lamps  slmul- 

tor  developing  nearly  ',i  II  I'    Machine  Is  shunt 
wound;  size  7  in.  high,  by  11%  In.  long  and 
in.  wide.    It  Is  the  cheapest  Dynamo  for  Its 
output  on  the  market. 
No.  AGEK  1209.  Electric  Here 
namu  .  shipping  Height,  40  lbs.  1 

always  in  stock 


$17.50 


■ent. 


The  "Electro"  Rheostat-Regulator 


"$.60 


J1ATE  SHIPMENTS 


'Electro"  Pony  Receiver 


Wh. 


I  In  i 


ivilll  \ 


■lephone  receiver,  ymi  have  a  dr.uble 

■eiver,  an  Invaluable  aeipilslt         t,.  thnse 

o  phone  In  nulsy  plnees  ,,r  t.,  |n  >>i>U-  hanl 
hearing.  It  can  ,-ilsn  liL.  used  fur  wireless 
though  Its  Imi  resistance  imn't  permit  of 
higher  resistance 


phor 

This  : 


md  results 

i  single  polo:  2'i 


$0.50 


IMMEDIATE  SHIPMENTS 


■  furnished  either  nickel  ph 


g'.ld  lac'iiHTCd.  They  are  made 
set  screws,  and  hlchh  p'tllslud. 
her  Inot  shi.un  in  Illustrations). 


"The  Livest  Catalog  in  America" 


Our  big,  new  electrical  cyclopedia  No.  18  Is  wait 
you.    Positively  the  most  complete  Wireless  and 
trienl  catalog  In  print  today,     200  Big  Fagcs, 
illusl  ral  Inns.    Tain    hist  rumen  Is    and    apparatus,  etc 
Big  "Treatise  on  Wireless  Telenraphy."    2i>  FREE 
ci.upims  fur  Mnir  HHi-pag..-  FHEE  Wireless  Cnurso 
in  2ii  ifssmis.    fit  EE  <>ci..|ivdin  No. 
7s3>4".    Weight       lb.    Beautiful  slirt  covers 
"THE  LIVEST  CATALOG  IN  AMERICA" 
Now  before  you  turn  this  pi 


mail     charges,     and    the     Cyclopedia  Is 

yours  by  return  mall. 
THE  ELECTRO  IMPORTING  CO. 
231  Fulton  Street,  New  York  City, 


231  FULTON  ST.,  NEW  YORK,  N.Y. 


194 


THE  ELECTRICAL  EXPERIMENTER 


July,  1917 


M  C2N5TRUQT2R 


An  Improved  Burglar  Alarm  Utilizing  the  "  Stick  Relay." 

By  ALBERT  H.  BEILER 


MANY  electrical  experimenters 
have  at  one  time  or  another  in- 
stalled a  burglar  alarm  in  their 
homes.  Most  of  the  burglar 
alarms  constructed  by  amateurs 
are  of  the  open-circuit  type,  and  have  there- 
fore several  disadvantages,  the  most  im- 
portant of  these  being,  that,  whereas  the 
opening  of  a  door  or  window  causes  the 
alarm  to  ring,  the  closing  of  the  door  or 
window  will  stop  the  alarm  again.  To  keep 
up  a  steady  ringing  requires  a  different  type 
of  circuit  than  that  usually  employed.  This 
may  be  of  either  the  closed  or  open  type. 
In  the  former,  the  current  flows  continu- 
ously and  the  opening  of  the  circuit  causes 
a  relay  to  release  its  armature  which  touches 
the  rear  contact  thereby  ringing  the  alarm. 
The  latter  type  is 
seen  in  the  continu- 
ous ringing  bell, 
with  which  most  of 
us  are  no  doubt 
familiar.  There  is 
another  open-circuit 
device,  however, 
which  is  less  known, 
called  a  stick  relay 
arrangement.  It  _  is 
this  last  one  which 
we  shall  consider  in 
detail. 

The  stic  k  relay 
is  used  extensively 
in  the  interlocking 
machines  for  rail- 
way signaling.  Its 
mode  of  operation 
insures  the  follow- 
ing result :  —  a  cir- 
cuit may  be  closed 
at  a  switch  but  not 
opened  again  at  the 
same  point ;  it  may 
be  opened  at  a  sec- 
ond switch  but  not 
closed  at  this  latter 
point.  To  illustrate 
this  a  little  more 
clearlv,  let  us  refer 
to  Fig.  1. 

When  the  main 
switch  M  is  closed, 
but  the  open  circuit 
door  or  window 
switch  O  kept  open, 
no  current  c  a  n 
travel  thru  the 

relay,  and  its  armature  wrill  be  drawn  away 
from  contact  C  by  a  retractile  spring.  If 
switch  O  is  now  closed,  either  by  opening 
the  door  or  the  window,  electro-magnet  R 
will  draw  its  armature  towards  it.  A  then 
touches  C,  and  the  current  has  two  paths 
to  travel,  i.e.,  one  by  way  of  the  open-circuit 
door  switch,  and  the  other  by  branching  off 
at  B,  going  thru  contact  C  and  the  arma- 
ture, thru  the  magnet  and  back  to  the  posi- 
tive main.  Should  O  now  be  opened,  it  will 
have  no  effect  on  electro-magnet  R,  since 
R  still  has  a  path  by  which  it  obtains  its 
source  of  current.  The  current  can  only  be 
shut  off  by  main  switch  M,  but  it  will  be 


noticed  that  once  M  is  opened,  its  subse- 
quent closing  will  not  energize  the  relay- 
again,  unless  O  is  closed. 

Fig.  2  shows  how  this  principle  is  used 
in  the  burglar  alarm.  The  relay  instead  of 
having  only  one  front  contact  has  two,  one 
for  keeping  its  own  circuit  closed  as  just 
described,  and  the  other  to  close  a  circuit 
for  ringing  an  alarm  bell.  The  relay,  which 
by  the  way,  is  only  wound  to  4  ohms,  oper- 
ates on  110  volts  in  series  with  a  lamp  or 
lamps,  which  are  connected  in  parallel  with 
one  another.  Thus  when  the  alarm  starts, 
not  only  will  the  bell  ring,  but  the  lamps 
will  light  and  assist  friend  burglar  towards 
a  hasty  departure.  The  relay  may  be  made 
to  operate  from  batteries  if  the  builder 
desires  to  dispense  with  the  lamps  ;  indeed 


indicated  in  Fig.  3.  Now  temporarily  re- 
move the  entire  armature  from  the  tele- 
graph sounder  and  file  the  end  down  half- 
way. (Fig.  3.)  Drill  and  tap  a  hole  as  indi- 
cated. Screw  the  piece  B,  on  to  it  so  as  to 
form  a  half  lap  joint.  Insert  adjusting 
screws  with  lock-nuts  into  the  end  holes  of 
B,  and  then  replace  the  armature  in  its 
frame. 

The  small  brass  pillars  A,  should  be 
screwed  onto  the  base  in  such  a  position 
that  when  the  armature  is  pulled  down,  the 
adjusting  screws  hit  the  centers  of  the 
pillars.  The  screws  must  be  exactly  ad- 
justed so  that  each  makes  contact  with  its 
pillar.  If  one  is  screwed  down  too  far,  the 
other  will  not  touch  its  pillar  or  front 
contact.  This  should  be  thoroly  tested  by 
an    electric  circuit. 


R  ?■  '.  I 


F,gl 


HOY 


Fig  6 


r/i 

r 

A 

V 

1 

0-32  tap 

*/9dn//  ,  #811  tap 


"•■>$s  I  o         ;  6 

r — *  1 

1  '    i!  1 

d  32  fop 

Fig  4-        Grei/nd  on  frame 


Working    Drawings   and    Diagrams   for   Constructing    a    Really    Reliable    and  Particularly 
Effective   Burglar  Alarm  Apparatus,  Employing  the  "Stick  Relay"  Principle.     Many  Other 
Applications  of  This  Relay  Will  Suggest  Themselves  to  the  Experimenter. 

the  same  source  of  current  that  rings  the 
bell  may  be  used  to  operate  the  relay. 

Since  double  contact  relays  are  rather  ex- 
pensive, a  good  substitute  that  will  cost 
very  little,  will  now  be  described.  Secure  a 
telegraph  sounder  (or  the  equivalent  parts 
from  a  large  electric  bell ;  also  the  parts 
may  be  easily  made),  one  wound  for  4 
ohms  is  best  if  the  lamps  are  to  be  used, 
also  a  piece  of  5/16"  square  brass,  2^" 
long,  and  two  pieces  of  Y%"  brass  rod  1" 
long.  The  two  pieces  of  rod  should  each 
have  a  hole  drilled  and  tapt  about  half-way 
thru  them  longitudinally.  The  5/16"  square 
brass  should  have  holes  drilled  and  tapt  as 


The  magnets  when 
energized  should 
draw  the  armature 
down  so  that  both 
front  contact  circuits 
are  closed.  Lamps 
or  bells  may  be  used 
to  test  the  continu- 
ity of  the  circuit  at 
the  contacts. 

Two  additional 
binding  posts  will  be 
needed  as  shown  in 
Fig.  4.  The  wiring 
on  the  instrument 
proper  is  m  a  d  e  as 
indicated. 

The  reader  will 
see  the  advantage  of 
this  type  of  burglar 
alarm  over  the  con- 
tinuous ringing  bell, 
because  the  alarm 
may  be  immediately 
shut  off  by  a  switch, 
and  be  ready  for 
another  alarm  an  in- 
stant later,  whereas 
with  the  continuous 
ringing  bell  an 
armature  must  be 
lifted  by  hand  and 
the  alarm  reset. 

A  few  auxiliary 
contrivances  may 
also  be  made  in  con- 
nection   with  the 
burglar  alarm.  The 
simple  burglar  alarm 
may  be  set  from  inside  the  house.  When 
a  person  leaves,  and  opens  the  door  it  will 
ring,  but  stop  when  he  closes  it.    This,  of 
course,  cannot  be  done  with  the  alarm  de- 
scribed herein,  and  a  means  must  be  em- 
ployed to  set  the  alarm  after  the  person  has 
closed  the  door  and  is  outside.    The  main 
switch  may  be  put  outside  the  house  and 
closed  when  leaving,  but  this  is  sometimes 
undesirable  where  there  is  no  good  means 
of  concealment. 

The  author  has  devised  a  little  contriv- 
ance wherein  the  alarm  is  set  from  the  out- 
side when  the  key  is  turned  in  the  lock,  in 
conjunction  with  another  device  which  rings 


July,  1917 


THE  ELECTRICAL  EXPERIMENTER 


the  alarm  as  soon  as  the  key  is  again  turned 
in  the  lock  to  open  the  door.  Tims  not  only 
will  the  alarm  ring  when  the  door  is  actual- 
ly opened,  hut  the  turning  of  the  key  will 


Special   Arrangement  of   Interlocking  Switches  for  Con- 
trolling  "Stick    Relay"   in    Burglar   Alarm    System  Here 
Described. 


setting  the  alarm*.  When  the  door  is 
opend  hy  the  key,  A  will  move  to  the  left 
without  carrying  the  switch  lever  with  it, 
thus  insuring  the  continuity  of  the  circuit. 

The  knob  H  is  used  for  push- 
ing the  knife  back  against  A, 
when  the  door  has  been  opened. 

When  the  author  installed  his 
alar  m  the  greatest  difficulty 
was  to  get  people  to  set  it. 

To  prevent  anyone  forgetting 
to  close  the  main  switch,  a  very 
simple  but  effective  device  was 
finally  resorted  to,  so  that  the 
alarm  is  always  set,  can  be  shut 
off  when  it  rings,  and  still,  a 
moment  after  having  stopt 
ringing,  it  is  set  again.  The 
main  switch,  instead  of  being  a 
knife  type,  is  a  two-way  snap 
switch,  connected  as  illustrated 
in  Fig.  6.  When  the  alarm 
rings  and  it  is  desired  to  shut 
it  off,  the  switch  need  only  be 
turned  once.  For  an  instant — 
the  time  it  takes  for  the  piece 
C,  to  snap  from  contacts  BE 
to  AD — the  circuit  will  be 
opened,  which  is  enough  time 
for  the  stick  relay's  armature  to 
be  raised.  The  switch  is  imme- 
diately closed  again  which, 
however,  does  not  start  the 
alarm  as  previously  explained. 

The  reader  can,  with  a  little 
ingenuity,  arrange  to  have  even 
the  turning  of  the  door  knob 
start  the  alarm.  This  should 
have  a  separate  switch,  how- 
ever, so  that  it  may  be  put  in 
operation  only  at  night,  whereas 
the  rest  of  the  alarm  may  be  in 
operation  all  the  time. 

Since  no  circuit  is  directly 
opened  or  closed  at  the  pillars 
and  since  consequently  no  arcs 
are  formed,  the  use  of  platinum 
contacts  is  unnecessary. 


start  it.  The  reader  can  arrange  to  ring 
the  alarm  by  so  much  as  inserting  a  key  in 
the  lock,  if  he  has  a  contact  insulated  from 
the  lock  frame,  and  which  will  touch  the 
frame  by  means  of  a  circuit  thru  the  key. 
This  latter  is  simple,  but  the  two  formerly 
mentioned  are  slightly  more  complicated. 

The  bar  A  (Fig.  5)  is  pivoted  to  B,  B  is 
pivoted  to  C,  while  C  is  fastened  to  a  base 
M  by  pin  P.  If  A  moves  to  the  right  or 
left  B  moves  to  the  right  or  left.  The 
movement  of  B  causes  C  to  travel  in  an 
arc  of  a  circle.  The  upper  part  of  C  en- 
gages a  stiff  spring  S,  in  its  travel,  but  only 
for  a  moment ;  for  when  A  has  moved  as 
far  to  the  right  as  it  can,  C  will  be  in  a 
position  to  the  left  of  S,  and  S,  which  will 
have  ceased  engaging  C,  will  spring  back 
to  normal.  When  A  is  moved  to  the  left, 
C  will  turn  clockwise,  again  engaging  spring 
S  and  carrying  it  to  contact  Q,  causing  it  to 
touch  Q..  This  closes  the  alarm  circuit; 
only  for  an  instant  it  is  true,  but  long 
enough  for  the  stick  relay  to  operate. 

The  part  A  is  rigidly  attached  to  the  lock 
lever  of  the  lock,  so  that  when  the  latter 
moves,  A  will  move  with  it.  When  the  door 
is  locked  by  the  key,  C  moves  counter- 
clockwise and  engages  S  so  that  S  does  not 
touch  Q.  Upon  opening  the  door,  however, 
S  touches  Q  and  the  alarm  is  rung.  These 
parts  should,  of  course,  be  firmly  covered 
over  with  a  steel  junction  box  attached  with 
blind  screws. 

The  method  for  closing  the  main  circuit 
by  means  of  the  door  key  will  now  be  de- 
scribed. In  Fig.  5,  it  will  be  seen  that  the 
upper  part  of  A  engages  a  bar  which  is 
attached  to  the  lever  of  a  switch,  K.  When 
A  moves  to  the  right  it  will  carry  this  lever 
along  with  it,  closing  the  main  switch  for 


*  The  switch  need  not  necessarily  be  the  main 
switch ;  it  may  be  any  switch  in  series  with  the 
line. 


A  K-TON  LIFTING  MAGNET. 

An  electro-magnet  that  is  capable  of  lift- 
ing about  1,000  lbs.,  may  be  easily  made. 
Its  current  consumption  is  about  5  amperes 
on  110  volts. 

The  body  of  the  magnet  consists  of  a  cir- 
cular piece  of  wrought  iron  or  steel  7^4 
inches  in  diameter  and  2  9/16  inches  thick. 
The  bottom  of  the  body  should  be  machined 
true  and  a  circular  groove  turned  out  in  it 
to  fit  the  magnet  coil.  The  outer  end  of  the 
groove  is  counterbored  1/16  of  an  inch 
deep  by  l-)4  inches  wide,  to  fit  a  brass  ring 
which  keeps  the  coil  in  place.  The  ring  is 
held  in  position  by  eight  small  flat-head 
screws.  When  fastened  in  place,  the  screws 
and  brass  plate  should  be  slightly  below 
the  surface  of  the  magnet  body. 

To  support  the  magnet,  three  screw  eyes 
of  3/16  inch  stock  should  be  provided  and 
fastened  in  three  tapt  holes  equally  spaced 
in  a  5  in.  diameter  circle,  or  one  V$  inch 
stock  screw-eye  may  be  placed  in  the  cen- 
ter as  shown.  For  winding  the  wire  coil, 
a  wooden  form  or  spool  must  be  provided.  It 
is  made  with  a  cylindrical  core  3j4  inches 
in  diameter  by  l'j  inches  long  and  slightly 
tapered,  so  that  the  coil  may  be  easily  re- 
moved when  finished. 

The  flanges  of  the  spool  are  7%  inches  in 
diameter  wooden  disks  fastened  on  the 
cylindrical  piece  so  as  to  be  easily  removed. 
The  spool  is  mounted  on  an  axle  or  between 
both  centers,  to  allow  it  to  rotate  wdiile 
winding  the  coil.  About  a  dozen  strips  of 
insulating  tape  are  equally  spaced  around 


195 

FLY  PAPER. 

Resin    8  parts 

Castor  oil   6  " 

Glycerin    3  " 

Dissolve  the  resin  into  the  other  two 
ingredients  by  the  aid  of  heat.  When  they 
become  a  liquid  spread  on  parchment  paper 
by  means  of  a  brush. 


"MOSQUITO  CHASERS." 

Oil  of  pennyroyal   1  oz. 

Castor  oil    3  " 

Alcohol    6  " 

Mix  together  and  apply  to  parts  of  body 
exposed  to  the  mosquitoes  and  they  will 
not  bite  or  come  near  it. 
Contributed  by 

ROBERT  THOMPSON,  Jr. 


the  spool  and  tied  or  pasted  in  place, 'fit- 
ting length-wise  with  the  spool  centers  and 
up  along  the  inner  side  of  both  flanges. 

The  coil  (for  110  volts  D.C.)  will  re- 
quire about  7  lbs.  of  Xo.  20  gage  wire,  sin- 
gle cotton  covered,  or  7  lbs.  of  Xo.  23  gage 
wire  for  220  volts,  D.C. 

In  starting,  about  1  ft.  of  wire  must  be 
allowed  for  a  magnet  lead  which  is  past 
thru  a  hole  near  the  center  of  one  of  the 
flanges.  Each  layer  should  be  insulated 
with  a  heavy  coat  of  thin  shellac.  When 
the  winding  is  finished,  about  1  ft.  of  wire 
must  be  left  for  the  other  lead.  The  strips 
of  tape  can  then  be  brought  over  and  pasted 
together  to  hold  the  coil  in  shape  and  in- 
sulate it  from  the  magnet  body.  Several 
turns  of  the  tape  are  then  wound  around 
the  outside  of  the  coil.  The  coil  may  then 
be  left  in  a  warm  oven  for  about  a  day  to 
let  the  shellac  harden. 

The  magnet  leads  are  spliced  to  a  piece 
of  heavy  lamp  cord.  A  Y%  inch  hole  should 
be  drilled  in  the  top  of  the  magnet  casting 
for  the  cord  and  bushed  with  a  fiber  in- 
sulating tube.  The  coil  should  then  be 
placed  in  the  magnet  body;  if  it  has  any 
play,  several  extra  layers  of  tape  can  be 
wound  on  the  coil  to  keep  it  sufficiently 
tight.  The  brass  plate  is  then  fastened  in 
place. 

To  suspend  the  magnet,  three  equal 
lengths  of  chain  are  attached  to  a  sup- 
porting ring;  the  loose  ends  are  fastened  to 
the  screw  eyes  to  keep  the  magnet  level. 
The  cord  is  then  attached  to  a  plug  to  make 
a  connection  with  a  110  volt  direct  current 
circuit.  It  is  not  adapted  for  operation  on 
alternating  current  circuits. 

Contributed  by  J.  LWAK. 


Something  Everyone  Finds  a  Need  for  at 
Some  Time  Is  a  Good  Lifting  Magnet.  Here 
Are  the  Details  for  Building  an  Efficient 
|/2-Ton  Electro- Magnet  for  Use  on  D.C. 
Circuits. 


96 


THE   ELECTRICAL  EXPERIMENTER 


July,  1917 


More  About  the  "Perpetual"  Electric  Clock 


THERE  appeared  in  the  June,  1916, 
Electrical  Experimenter,  a  de- 
scription of  a  proposed  perpetual 
electric  clock  and,  in  August  of  the 
same  year,  an  explanation  of  why 
the  same  would  not  operate  indefinitely. 
That  the  plan  is  entirely  feasible,  provided 
a  small  amount  of  energy  be  supplied  from 
some  outside  source,  may  be  seen  from  the 
following  description  and  illustrations  of  a 
similar  device  recently  constructed  at  Stan- 
ford University. 

In  connection  with  some  research  work 
in  Aerodynamics,  need  arose  for  an  in- 
strument which  would  close  a  battery  cir- 
cuit momentarily 
at  one  second  in- 
tervals. As  a  sub- 
s  t  i  t  u  t  e  for  a 
standard  seconds 
pendulum,  an 
electro  -  magnet- 
ically actuated 
clock  was  built 
which  is  capable 
of  performing  the 
desired  service 
very  satisfac- 
torily. 

The  photo- 
graphs show  the 
construction 
clearly.  The  de- 
tails may  be  seen 
from  the  draw- 
ing. The  frame 
is  of  small  iron 
pipe  and  the  table 
of  thin  steel 
plate.  The  pendu- 
lum consists  of  a 
round  steel  rod 
with  two  attached 
weights.  It  is 
h  u  n  g  on  thin 
flexible  steel 
springs  from  the 

short  piece  of  angle  iron  shown,  thus  being 
free  to  swing  with  a  minimum  of  friction. 

The  period,  that  is,  the  time  of  one 
swing  of  a  pendulum,  depends  upon  its 
length  and  the  distribution  of  its  weight. 
Near  the  bottom  of  the  pendulum  rod  is 
a  large  iron  cylinder  (part  No.  7)  which 
may  be  moved  up  or  down.  The  upper 
end  of  the  rod  is  threaded  to  receive  the 
nut,  16.  Coarse  or  fine  adjustment  of  the 
periodicity  is  thus  secured  by  shifting  one 
or  the  other  of  these  weights. 

On  top  of  the  plate  is  mounted  a  Veeder 
stroke  counter,  actuated  thru  links  from 
the  pendulum  rod.  This  device,  together 
with  a  stop  watch,  facilitates  the  calibra- 
tion and  adjustment  of  the  clock. 

A  solenoid  consisting  of  2,700  turns  of 
No.  26  B.  &  S.  gage  insulated  copper  wire 
is  attached  to  the  lower  part  of  the  frame. 
To  the  bottom  of  the  pendulum  is  fast- 
ened a  bundle  of  closely  bound  iron  wires. 
This  curved  plunger  moves  in  and  out  of 
the  solenoid  as  the  pendulum  swings.  The 
coil  is  energized  from  either  the  110  volt 
lighting  circuit  with  a  lamp  in  series  there- 
with, or  from  3  dry  cells  without  the  lamp. 

It  is  necessary,  of  course,  to  have  some 
arrangement  which  will  close  the  circuit 
thru  the  solenoid  when  the  plunger  is  mov- 
ing toward  it,  and  open  the  circuit  when 
the  plunger  is  moving  away.  Accordingly, 
a  six-tooth  ratchet-wheel  is  fitted  on  a 
short  horizontal  shaft,  and  a  commutator 
having  the  same  number  of  brass  and  of 
fiber  segments  of  equal  width,  is  placed  be- 
side it.  The  shaft  is  mounted  in  plain 
bearings  on  top  of  the  plate.    To  the  pen- 


By  HOWARD  W.  LEWIS 

Chairman  Stanford  University  Branch  of  A.  I.  E.  E. 

dulum  rod  is  attached  a  flat  link  with  a 
hook  on  its  outer  end,  which  engages  with 
the  ratchet-wheel  and  turns  it  one-sixth 
of  a  revolution  for  each  alternate  stroke 
of  the  pendulum.  A  copper  leaf  brush 
bears  against  the  commutator  from  below. 
When  the  plunger  is  moving  away  from 


In  Connection  with 
Some  Research 
Work  in  Aerody- 
namics Need  Arose 
for  an  Instrument 
that  Would  Close 
a  Battery  Circuit 
at  One  Second  In- 
tervals, the  Appa- 
ratus Shown  Hav- 
ing Fulfilled  the 
Requirements  Very 
Satisfactory.  A  s 
a  Test  It  Was 
Run  for  24  Hours 
with  a  Deviation 
of  a  Few  Seconds 
Only. 


the  solenoid  and  the  hook  is  consequently 
reaching  forward  to  pick  up  the  next  tooth 
of  the  ratchet-wheel,  this  brush  rests  on  a 
fiber  segment  and  the  circuit  thru  the  coil 
is  open.  On  the  return  stroke,  however, 
the  hook  pulls  a  live  (brass)  segment 
under  the  brush  and  current  flows  into  the 
coil,  which  thus  exerts  a  powerful  pull  on 
the  plunger.  Before  the  plunger  reaches 
the  end  of  its  travel,  a  dead  (fiber)  seg- 
ment rolls  under  the  brush,  the  solenoid 
releases  its  pull  on  the  plunger,  and  the 
pendulum  swings  back  to  repeat  the  cycle. 
The  relative  positions  of  the  ratchet-wheel 
and  commutator  are  adjustable  on  the 
shaft,  so  that  the  time  of  excitation  of  the 
solenoid  can  be  placed  at  any  desired  point 
in  the  stroke  of  the  plunger.  An  adjustable 
condenser  of  several  microfarads'  capacity 
is  used  to  eliminate  the  spark  between 
commutator  and  brush. 

The  secondary  circuit,  for  whose  opera- 
tion this  clock  was  built,  is  closed  once 
each  cycle  between  a  phosphor  bronze 
spring  and  the  pendulum.  The  duration  of 
the  closure  of  this  circuit  can  be  adjusted 
by  turning  the  screw  (see  details,  part  No. 

19)- 

Considerable  time  and  attention  was 
given  to  designing  this  mechanism  along 
correct  principles  and  it  has  been  very 
carefully  constructed.  The  results  attained 
justify  the  trouble  involved.  After  a  pre- 
liminary adjustment,  a  continuous  run  of 
24  hours'  duration  showed  a  deviation  of 
only  a  fczv  seconds  from  a  standard  clock. 
Furthermore,  it  closes  the  secondary  cir- 
cuit at  regular  intervals,  quite  as  well  as  a 


standard  seconds  pendulum  costing  several 
hundred  dollars. 

The  original  design  of  "Perpetual  Motion" 
Clock  involved  the  action  of  a  swinging 
permanent  magnet,  which,  as  it  swung  into 
the  coil,  was  supposed  to  develop  sufficient 
energy  to  keep  the  clock  going  forever. 

Upon  request  of  the  Editors,  the  author 
made  a  quantitative  electrical  measurement 
upon  this  device.  For  one  thing  he  soon 
discovered  that  operating  it  upon  batteries 
was  too  expensive,  as  it  is  now  in  con- 
tinuous service  eight,  and  often  more  hours 
per  day.  It  is  now  operated  thru  the  me- 
dium of  a  bell-ringing  transformer.  The 
secondary  circuit 
which  it  operates 
is  energized  by 
batteries,  how- 
ever. 

The  point  was 
raised  as  to  the 
magnitude  of  the 
induced  current 
in   the  coil. 

In  order  to  an- 
swer this  ques- 
tion the  author 
made  a  simple 
test  which  con- 
vinced him  that 
the  transient  phe- 
nomena referred 
to  are  inappreci- 
able c  o  m  p  a  red 
with  either  the 
normal  current 
thru  the  solenoid, 
or  the  current  in 
the  secondary 
(battery)  circuit. 
These  experi- 
ments were  as 
follows : 

(A)  Solenoid 
entirely  discon- 
nected from  the 
source,  then  connected  directly  to  the  ter- 
minals of  D.  C.  milli-ammeter.  No  effect 
was  produced  on  ammeter  needle  when  the 
plunger  was  rapidly  moved  in  and  out  of 
the  solenoid.  Same  absence  of  effect  noted 
when  telephone  receiver  was  used  as  cur- 
rent detector.  Very  slight  deflection  when 
sensitive  ballistic  galvanometer  was  used 
as  current  detector. 

This  is  exactly  what  might  be  expected, 
since  there  is  no  field  produced  by  the 
solenoid,  as  there  is  no  exciting  current 
thru  it.  I  take  it  that  what  small  current 
there  is  induced  in  the  solenoid  is  due  to 
the  rapid  motion  thru  it  of  the  minute 
remanent  field  in  the  plunger.  However 
as  this  is  composed  of  a  bundle  of  fine, 
soft  iron  wires,  this  residual  magnetism  is 
very  small. 

(B)  Solenoid  connectly  directly  (without 
ratchet  wheel  or  commutator)  to  D.  C. 
source;  current  in  the  circuit  as  indicated 
by  milli-ammeter  was  0.26  amp.  Plunger 
rapidly  moved  in  and  out  of  the  solenoid 
by  hand.  Effect:  When  plunger  was 
forced  in,  current  decreases,  while  the 
plunger  was  moving,  about  Yz  milli-ampere. 
When  the  plunger  was  drawn  out,  current 
increased,  while  the  plunger  was  moving 
about  l/i  milli-ampere.  As  soon  as  the 
plunger  was  stopt  from  moving,  or  as  soon 
as  it  had  moved  out  of  influence  of  the  so- 
lenoid, this  transient  current  increment  or 
decrement  stopt  and  the  current  returned 
to  its  normal  value  in  the  circuit,  as  de- 
termed  by  Ohm's  law,  i.  e.,  0.26  amp. 

This  again  is  exactly  in  accordance  with 
the  theory   involved,   that   is,   when  the 


July,  1917 


THE   ELECTRICAL  EXPERIMENTER 


197 


plunger  was  moving  into  the  solenoid  the 
flux  threading  the  latter  was  increasing  at 
a  rapid  rate,  due  to  the  decreasing  reluct- 
ance of  the  magnetic  circuit,  the  magneto- 
motive force  meanwhile  remaining  con- 
stant. This  change  of  flux  induced  a  volt- 
age in  the  turns  of  the  solenoid  which 
tended  to  oppose  the  E.M.F.,  which  was 
forcing  the  current  thru  the  coil ;  in  other 

di 

words  it  is  the  well-known  law  L  =  — . 

dt 

It  is  exactly  analogous  to  the  similarly 
induced  counter  E.M.E.  which  arises  in  a 
coil  to  oppose  the  flow  of  current  therein 
when  the  coil  is  first  connected  to  a  source 
of  continuous  voltage.  Due  to  the  fact, 
however,  that  the  movement  of  the  plunger 
could  not  under  any  conditions  compare  in 
rapidity  with  the  rise  of  current  in  an 
inductive  circuit,  this  counter  E.M.F.  is 
'undoubtedly  very  much  smaller  than  it 
would  be  if  the  solenoid  permanently  sur- 
rounded the  core  and  the  current  were 
then  establisht  in  the  coil. 

A  moment's  reflection  will  explain  the 
observed  phenomena  when  the  plunger  was 


drawn  out  of  the  solenoid  along  a  very 
similar  line  of  thought.  It  is  exactly  anal- 
ogous to  the  arc  that  follows  the  opening 
of  a  switch  in  an  inductive  circuit.  The 
collapsing  magnetic  field  induces  a  volt- 
age in  the  coil  which  tends  to  maintain 
the  current. 

[Of  course  if  the  moving  core  had  been 
of  steel,  powerfully  magnetised,  the  effects 
noted  would  have  been  much  more  pro- 
nounced.— Ed. J 


WHAT  TO  DO  WHEN  ACIDS  ARE 
SPILLED. 

The  safest  course  is  not  to  spill  the  acid; 
the  next  best  is  to  apply  an  alkaline  solu- 
tion at  once,  or  cover  with  chalk.  It  is 
a  good  plan  to  keep  a  jar  of  strong  wash- 
ing soda  solution  always  ready  in  case  of 
emergency.  The  reason  for  using  a  jar 
instead  of  a  bottle  is  that  the  solution  can 
be  poured  over  the  spilled  acid  more 
quickly.  A  loose  cardboard  cover — the  lid 
of  a  box — will  serve  to  keep  out  dust,  and 
more  water  can  be  added  when  necessary 
to  make  up  for  evaporation.    A  cocoa  tin 


Brass  ^ 

- — ij' — . 

>«_M 

■I 

1      '  / 

Steel  spring  y 
1 

1 

it 

containing  crushed  chalk   should   also  be 

kept  handy  in  case  any  quantity  of  strong 
acid  is  spilled. 

Contributed  by  H.  J.  GRAY. 


MULTIPLE  TELEPHONE  AND 
TELEGRAPH  "PHANTOM" 

SYSTEM. 
By  L.  R.  W.  Allison,  Assoc., 
A.  I.  E.  E. 
The  complementary  relation  between  the 
telephone  and  telegraph  system  is  particu- 


le/epbone 


k/tpfi, 


telephone 


Details  of  All  Parts  Necessary  to  Build  a  Standard  Seconds  Pendulum  for  Use  in  Closing 
a  Secondary  Circuit  at  Exact  Intervals,  Et  Cetera. 


Schematic  Diagram  Showing  How  Three 
Telephone  and  Eight  Telegraph  Messages 
Are  Transmitted  Simultaneously  Over  Two 
Telephone  Circuits.  The  A.  T.  and  T.  Co.'s 
Method. 

larly  interesting  and  instructive.  The  ac- 
companying diagram  shows  the  method  of 
wiring  for  multiple  telegraphy  as  arranged 
by  the  American  Telephone  and  Telegraph 
Company,  indicating  two  telephone  circuits, 
totaling  four  wires,  which  provide  for  the 
transmission  simultaneously  of  a  maximum 
of  three  independent  telephone  conversa- 
tions and  eight  distinct  telegraph  messages 
without  any  interference  with  each  other. 

The  telephone  circuit  consists  of  two  cop- 
per wires  of  approved  construction,  ar- 
ranged in  specific  relation  to  each  other  and 
transposed  at  frequent  intervals  to  reduce 
the  inductive  effects  to  a  minimum.  This 
pair  of  wires  forms  a  metallic  circuit, 
equipped  with  auxiliary  apparatus,  loading 
coils,  etc.,  connected  with  a  switchboard. 
As  will  be  noted  from  the  diagram,  one 
wire  of  each  pair  is  employed  to  form  the 
third  telephone  circuit. 

The  telegraph  circuit  comprises  one  wire, 
grounded  to  the  earth  to  make  the  neces- 
sary return,  and  which  may  be  divided  into 
several  distinct  circuits  for  the  transmission 
of  messages. 

Each  of  the  four  telephone  wires  is  ca- 
pable of  providing  for  a  telegraph  circuit  at 
the  same  time  the  lines  are  being  used  for 
telephone  service.  The  telegraph  circuit  is 
thus  superimposed,  and  can  be  divided  into 
a  duplex  system  of  two,  four  or  eight 
working  telegraph  circuits,  each  of  which 
may  be  employed  for  the  transmission  of 
telegraph  messages.  The  telephone  circuit 
proper  can  only  be  used  for  telephonic  pur- 
poses by  the  two  parties  in  direct  communi- 
cation, during  the  period  of  connection,  as 
will  be  readily  understood. 

This  complementary  relation  between  the 
telephone  and  telegraph  shows  that  tele- 
phone toll  and  long-distance  lines  may  be 
used  for  telegraph  purposes,  but  existing 
telegraph  lines  cannot  be  employed  for  tele- 
phone service  until  reconstructed  and  ar- 
ranged in  the  manner  indicated  in  the  dia- 
gram. 

In  connection  with  this  effective  wiring 
arrangement  it  is  interesting  to  note  that 
this  possible  interchange  of  system  and  serv- 
ice brings  about  greater  economv  in  the 
use  of  joint  facilities  of  both  telephone  and 
telegraph  plants,  including  both  lines  and 
terminal  stations.  Quite  naturally,  there 
are  great  advantages  to  be  derived  thru 
the  use  of  a  joint  "wire  plant,"  utilizing  for 
both  telephone  and  telegraph  the  operating 
facilities  that  would  ordinarily  be  employed 
for  a  single  purpose  only. 


198 


THE  ELECTRICAL  EXPERIMENTER 


July,  1917 


A  "GEISSLER  TUBE"  EASILY 
MADE. 

Now  that  Geissler  tubes  are  hardly  pro- 
curable at  any  cost,  I  think  that  this  article 
will  prove  of  interest  to  all  who  have 
wanted  a  Geissler  tube.     Below  are  full 


ELECTRIC  IGNITER  FOR  FIRING 
A  CANNON. 

After  having  some  experience  with  firing 
a  cannon  by  fuses,  lighting  paper,  and  sev- 
eral other  methods  used,  and  getting  a  taste 
of  powder  at  one  time,  I  decided  to  make 


WAX     \  NEEDLE 


FIG.I 

'SPARK  COIL 


NEEDLE 


WAX 


F1G.H 


AIR  SPACE 


Details  for  Making  a  Home-Made  Geissler  Tube  from  an  Incandescent  Lamp  and  Appearance 
of  Completed  Bulb  When  Excited  from  Even  a  Small  Spark  Coil. 


directions  for  making  such  a  tube  from 
a  burned-out  lamp  bulb,  providing  the 
vacuum  is  not  destroyed. 

Take  a  piece  of  sealing  wax  and  soften 
it  so  that  it  can  easily  be  prest  into  a 
shape  somewhat  like  that  in  Fig.  1.  Then 
hollow  out  the  center  as  in  Fig.  2.  Stick 
a  needle  thru  the  wax  and  while  still  soft 
and  hot  press  the  wax  firmly  against  the 
side  of  the  bulb  as  in  Fig.  3,  taking  care 
that  the  wax*  is  air-tight.  Then  connect 
one  terminal  of  a  1  inch  spark  coil  to 
the  needle  in  the  wax  and  the  other  ter- 
minal to  the  base  of  the  lamp.  Turn  on 
the  current  and  the  spark  will  puncture 
the  glass  and  the  effect  produced  will  be 
that  of  a  high  grade  Geissler  tube.  The 
purpose  of  the  hollow  space  in  the  wax  is 
as  follows: 

This  space  is  filled  with  air  and  when 
the  spark  punctures  the  glass,  the  air  in 
this  space  rushes  inside  the  bulb;  in  this 
way  regulating  the  amount  of  air  in  it. 
Different  colors  are  obtained  with  differ- 
ent air  holes,  that  is,  the  larger  the  hollow 
space  in  the  wax,  the  more  air  in  the  bulb. 

When  inserting  the  needle  thru  the  wax, 
take  care  that  it  just  touches  the  glass  of 
the  light  bulb. 

I  have  used  this  method  of  making 
Geissler  tubes  for  years  and  I  have  found 
that  it  never  fails  to  produce  the  desired 
results ;  as  good  as  any  tube  I  have  bought. 
As  the  cost  of  each  tube  is  very  slight,  and 
every  tube  made  produces  a  different  color, 
I  have  found  it  very  interesting  to  make 
a  great  number  of  them. 

Contributed  by  DAVID  GOODMAN. 


something  which  would  be  entirely  safe 

and  sane. 

This' apparatus  costs  but  little,  to  which 
is  added  the  fact  that  it  is  safe.  It  is  a 
good  thing  to  be  used  at  a  camp  when  fir- 
ing a  cannon  for  the  raising  and  lowering 
of  the  flag,  and  is  a  safe  way  in  which  to 
fire  a  cannon  on  July  4th. 

The  apparatus  can  be  placed  as  far  as  75 
yards  away  from  the  cannon.  The  things 
needed  would  be  1  push  button,  3  dry  cells, 
2  binding  posts,  a  small  (%"  spark)  spark 
coil,  about  4  square  feet  of  y2  inch  poplar 
or  pine,  some  shellac,  screws  and  wire.  I 
would  recommend  a  section  of  a  Ford  coil 
which  can  be  bought  for  a  reasonable 
amount. 

The  inside  measurement  of  the  box  should 
be  13I2/'  by  8T4"  by  3",  the  compartment 
for  the  batteries  A,  A,  A,  being  8*4"  by 
6/4"  by  3"  separated  by  a  partition,  and  then 
a  compartment  6T  i"  by  3l/2"  by  3"  or  any 
suitable  size  for  the  spark  coil  which  you 
have.  The  bottom  and  top  should  be  made 
about  1z"  larger  than  the  outside  size  of  the 
box  for  the  sake  of  appearance.  When 
putting  the  box  together  all  joints  should  be 
made  by  painting  them  with  shellac  and  be- 
fore it  dries  screw  it  down  tight  so  it  will 
be  water-tight  and  damp-proof.  When 
connecting  the  batteries  leave  plenty  of 
wire  for  connections.  The  push  button  C, 
which  is  to  complete  the  primary  circuit  to 
operate  the  coil,  should  be  fastened  on  the 
cover  above  the  compartment  which  has 
nothing  in  it. 

The  secondary  binding  posts  "F"  in  the 
diagram  should  be  fastened  on  the  cover 


above  the  spark  coil,  and  be  sure  the  wires 
are  carefully  insulated  from  each  other. 
After  the  box  is  made  and  put  together 
give  it  about  5  coats  of  shellac  to  make  it 
damp-proof.  Shellac  both  inside  and  out- 
side. 

Before  fastening  the  spark  coil  in  the 
box  be  sure  the  coil  is  adjusted  to  its  best 
secondary  output  when  connected  to  the 
batteries  which  are  to  be  used. 

Up  to  about  75  yards  this  will  fire  a 
cannon  with  one  side  of  the  secondary 
grounded  and  the  other  secondary  wire  run 
through  the  air.  This  wire  is  supported 
by  insulated  wood  sticks  stuck  into  the 
grounds.  Have  the  cannon  grounded  and 
the  end  of  the  wire  about  from  the 
one  side  of  the  fuse  hole  with  powder 
around  it.  Then  if  everything  is  arranged 
as  described,  when  the  button  is  presst 
the  powder  will  go  up  in  smoke.  For  firing 
a  cannon  more  than  75  yards  from  appa- 
ratus run  one  wire  along  on  the  ground 
and  the  other  through  the  air.  Connect 
the  ground  wire  to  the  cannon.  Fix  the 
air  wire  as  described  before.  This  you  will 
find  is  a  very  safe  way  to  fire  a  cannon.  . 

Code  to  Drawing:  A,  batteries;  B,  spark 
coil ;  C,  push  button  on  top  of  cover ;  D, 
primary  circuit;  E,  secondary  circuit;  F, 
secondary  binding  post  on  top  of  cover; 
G,  partition  separating  batteries;  H,  parti- 
tion separating  spark  coil;  K,  spark  coil 
vibrator. 

In  using  this  apparatus  to  fire  a  cannon 
with,  make  it  a  rule  not  to  have  the  sec- 
ondary leads  over  20  to  30  feet  long.  These 
spark  leads  should  be  well  insulated  (at 
least  one  of  them)  and  the  primary  push 
button  wires  can  be  of  any  length  desired 
up  to  50  or  75  feet,  but  20  feet  is  usually 
sufficient. 

Some  constructors  make  their  cannon  to 
accommodate  a  standard  gasoline  engine 
spark  plug  at  breech.  Others  arrange  an 
insulated  wire  as  shown  in  the  accompany- 


An    Electric    Igniter   for   the    Toy  Cannon 
Which    Will    Save    Fingers,    Mis-Fires  and 
Premature  Explosions. 


ing  sketch.    This  apparatus  has  been  used 
very  successfully  by  the  Erie  Y.  M.  C.  A. 
and  the  Erie  Boys'  Club  of  Erie,  Pa. 
Contributed  by 

GILBERT  CROSSLEY. 


July,  1917 


THE  ELECTRICAL  EXPERIMENTER 


This   department   will   award   the  following  monthly   prizes:     First   Prize,  $3.00;  Second   Prize,  $2.00;  Third   Prize,  $1.00. 

The  purpose  of  this  department  is  to  stimulate  experimenters' towards  accomplishing  new  things  with  old  apparatus  or  old  material, 
and  for  the  most  useful,  practical  and  original  idea  submitted  to  the  Editors  of  this  department,  a  monthly  series  of  prizes  will  be 
awarded.  For  the  best  idea  submitted  a  prize  of  $3.00  is  awarded;  for  the  second  best  idea  a  $2.00  prize,  and  for  the  third  best  prize  of 
$1.00.  The  article  need  not  be  very  elaborate,  and  rough  sketches  are  sufficient.  We  will  make  the  mechanical  drawings.  Use  only  one 
side  of  sheet.    Make  sketches  on  separate  sheets. 


FIRST  PRIZE,  $3.00 


SECOND  PRIZE,  $2.00 


THIRD  PRIZE,  $1.00 


AN  EFFICIENCY  PLIER  KINK. 

Nature  provides  for  average  conditions 
only  and  she  supplied  us  with  a  reasonably 
thick  skin  where  it  is  called  upon  to  do 
extraordinary  amount  of  work  or  wear,  but 
one  of  the  spots  neglected  by  bountiful 
nature  is  on  the  back  of  the  index  linger, 
between  the  first  and  second  joints  of  the 
right  hand.  This  is  the  spot  that  is  charged 
with  the  duty  of  opening  "diagonals," 
"long-nose,''  "goose-bill"  and  the  common, 
ordinary,  everyday  pliers,  and  on  this  spot 
more  blisters  can  be  raised  to  the  square 
inch  than  on  any  other  spot  on  our  an- 
atomy. 

The  photograph  clearly  shows  how  to 
"save  your  skin"  and  while  it  will  save 
more  time  than  skin,  it  is  our  skin  that 
we  are  most  considerate  of. 

The  spring  that  holds  the  legs  apart 
should  be  made  of  spring  brass,  phosphor 


Do  You  Want  to  Save  Your  Skin  and  Your 
Temper?    Then  Simply  Fit  Your  Pliers  with 
a  Steel  or  Bronze  Spring  Like  That  Shown 
and  Your  Worries  Will  Be  Over. 

bronze  or  German  silver  and  it  is  soldered 
to  one  leg,  or  if  soldering  offers  any  dif- 
ficulty the  spring  may  be  riveted  to  the  leg. 

This  kink  is  particularly  useful  in  tele- 
phone exchanges  in  trimming  terminal  racks 
or  cable  and  relay  work,  where  it  is  neces- 
sary to  cut  and  trim  wires  by  the  hour 
and  which  operation  wears  off  considerable 
"bark."  The  kink  also  allows  the  use  of 
all  fingers  for  pressure  on  the  legs. 

Contributed  by 

FRED'K  J.  SCHLINK. 


A  "EAMBOO"  FLASHLIGHT  NOV- 
ELTY. 

A  distinct  and  useful  novelty  in  electric 
flashlights  is  here  shown  and  described.  To 
make  it,  first  secure  a  battery  for  a  tubular 
flashlight.  A  piece  of  bamboo  with  an 
inside  diameter  the  same  or  nearly  the 
same  as  that  of  the  battery  is  then  obtained. 
The  length  of  the  bamboo  is  slightly  great- 
er, say  an  inch  and  a  half,  than  the  battery. 
The  bamboo  must  have  a  joint  about  a  half 
inch  from  one  end.  A  hole  is  bored  thru 
the  center,  just  large  enough  to  permit  the 
flashlight  bulb  to  fit  tightly.  A  piece  of 
bright  tin,  shaped  right,  is  placed  around 
the  bulb  to  act  as  a  reflector.    A  cork  is 


A  GAGE  THAT  INDICATES  RELA- 
TIVE MAGNETIC  ATTRACTION 
OF  METALS. 

The  experimenter  may  often  want  to  test 
the  effect  of  different  metals  under  mag- 


With  This  Simple  Home-Made  Testing  De- 
vice the  Amateur  Can  Make  Interesting 
Investigations  of  the  Relative  Magnetic 
Attraction  of  Various  Metals,  Both  Ferric 
and  Non-Ferric. 

netic  influence  and  an  instrument,  con- 
structed by  the  writer,  to  determine  this 
particular  effect  is  shown  in  the  accompany- 
ing illustration.  The  action  of  the  appa- 
ratus as  shown  in  the  photo  is  very 
evident.  As  soon  as  a  current  is  past  thru 
the  electro-magnet,  the  metal  strip  to  be 
tested  is  either  attracted  or  left  neutral. 
In  some  metals  as  iron  or  steel,  the  arma- 
ture or  testing  strip,  wall  be  moved  consid- 
erably, but  other  metals  like  copper,  lead, 
zinc  are  not  affected  at  all.  The  effect  of 
the  magnet  upon  these  latter  metals  can, 
however,  be  easily  detected  by  so  construct- 
ing the  indicator  that  it  will  register  the 
least  perceptible  movement  of  the  armature. 
It  is  quite  evident  that  the  slightest  move- 
ment of  the  rod  will  move  the  pointer 
over  a  considerable  distance.  By  passing 
AC  thru  the  magnet  coil  the  relative  mag- 
netic repulsion  of  metals  may  be  tested. 

The  indicator  arrangement  may  be  con- 
structed from  an  old  steam  gage  or  clock 
works.  The  pivot  block  can  be  obtained 
from  an  old  bell.  Care  must  be  used  in 
making  the  instrument  so  that  there  is  very 
little  iriction  in  the  pivot  rod  support 
or  in  pinion  and  gear  of  the  indicator. 

Contributed  by  MARK  SLABODNIK. 

placed  at  the  bottom  to  keep  the  battery 
from  falling  out.  The  contact  is  made  as 
shown  in  the  diagram,  by  means  of  the 
brass  spring. 

Contributed  by  EDMUND  ANGLIN. 


Lamp 


no 


/r~r-.'  v — re f tec  for. 
nuti  button  , 


A  Distinct  Novelty  in  Flashlights — It's  Made 
of  Bamboo  and  Will  Make  a  Very  Attractive 
Gift  or  Favor  for  Parties  and  Dinners. 


AN  EMERGENCY  FUSE  PLUG. 

Here  is  a  little  idea  of  my  own  on  an 
"Emergency  Fuse."  Take  an  ordinary  at- 
tachment plug  and  connect  the  terminals 


A   SUBSTITUTE  FOR  SWITCH 
CONTACT  POINTS. 

When  in  need  of  switch  contact  points, 
old  used  .32  or  .25  caliber  cartridges  come 
in  handy.  The  "Radio-bug"  with  a  lean 
pocketbook  can  construct  these  at  practi- 
cally no  cost. 

First  clean  the  inside  of  the  cartridge 
shell  from  all  dirt,  by  using  a  small  pen- 
knife or  half-round  file.  Next  take  a  com- 
mon brass  wood  screw  that  will  fit  inside 
the  cartridge  and  place  it  inside  one  which 
has  been  cleaned.  Now  pour  solder  in  and 
you  then  have  a  serviceable  contact  point 
It  is  perhaps  better  to  put  a  drop  of  zinc 
chlorid  on  the  inside  of  the  cartridge  to 
make  the  solder  stick  better. 

If  screws  are  used  which  will  come  thru 
on  the  rear  of  the  base,  wires  may  easily 
be  soldered  to  them. 

Contributed  by      G.  GRANT  WAITE. 


Save  Your  Cartridge  Shells,  Boys.  They 
Make  Good  Switch  Points,  if  a  Wood  or 
Machine  Screw  Is  Firmly  Embedded  in  the 
Shell  by  Means  of  Solder.  The  Leads  May 
Be  Soldered  to  the  End  of  the  Screw. 


A  PECULIAR  STATIC  ELECTRICAL 
PHENOMENON. 

I  am  a  stenographer,  employed  in  an 
architect's  office,  and  my  duty  is  to  write 
specifications,  ten  copies  at  a  writing.  In 
writing,  a  static  charge  is  generated  on 
each  of  the  carbon  papers,  which  is  sep- 
arated from  the  next  by  the  white  paper. 
On  separating  the  carbons  from  the  white 
papers,  which  is  done  by  pulling  the  ends 
of  the  carbons,  which  protrude  beyond  the 
white  papers,  with  one  hand  and  the  white 
papers  themselves  with  the  other  hand, 
some  of  the  charges  are  neutralized  on 
separation  ;  sharp  crackling  being  indicative 
of  this.  I  usually  place  all  of  the  carbons 
onto  the  machine,  after  which  I  draw  quite 
a  long  spark  from  any  part  of  the  ma- 
chine into  my  knuckle. 

At  first  I  received  the  shock  unexpectedly 
after  bringing  my  hand  near  the  charged 
machine,  as  I  had  formed  a  habit  of  plac- 
ing the  carbons  onto  the  machine  after 
each  writing.  After  investigating  the  mat- 
ter, I  found  that  the  mysterious  "what-is- 
it"  was  developed  in  the  machine. 

Contributed  by  WM.  LESKY. 

with  a  small  piece  of  common  screen  wire. 
A  single  strand  of  wire  will  pass  about 
3  amperes;  .3  strands  6  amperes,  and  6 
strands  about  10  amperes. 
Contributed  by  HUBERT  YEAGER. 


200 


THE  ELECTRICAL  EXPERIMENTER 


July,  1917 


Where  the  Radio  Amateur  Fits  in  the  U.  S.  Naval  Reserve 

By  M.  B.  WEST,  RADIO  GUNNER,  U.  S.  N.  R.  F. 


THE  amateur  has  at  last  an  oppor- 
tunity to  be  of  real  service  to  the 
Government,  and  one  that  will  not 
in  any  way  interfere  with  his 
career  in  civil  life.  The  argument 
that  the  amateur  would  be  of  inestimable 
benefit  in  time  of  war  has  so  often  been 
made  that  it  has  at  last  been  recognized. 
Yet  it  is  clear  to  anyone  who  gives  it  a 
moment's  thought,  that  without  at  least 
some  preliminary  training  most  amateurs 
would  fail  miserably  if  suddenly  placed  in 
charge  of  a  large  radio  station. 

It  is  with  the  intention  of  remedying 
this  situation,  that  the  Class  4,  Naval  Re- 
serve, has  been  created.  In  as  far  as 
possible,  it  is  hoped  that  amateurs  enroll- 
ing in  the  reserve  will  at  once  ask  for  a 
short  period  of  active  duty  so  as  to  be- 
come familiar  with  the  requirements  of 
the  radio  work  of  the  navy.  Then  they 
will  return  home,  and  it  is  hoped  will  join 
one  of  the  drill  routes  that  have  been  or- 
ganized in  connection  with  the  Naval  Sta- 
tions. The  purpose  of  these  drill  routes 
is  to  perfect  these  amateurs  in  handling 
radio  business  according  to  the  rules  of 
the  navy. 

And  think  what  a  difference  it  would 
make  in  amateur  working  conditions  if  all 
amateur  business  was  handled  in  an  orderly 
and  thoroly  efficient  manner ! 

These  drill  routes  will  be  placed  under 


the  direction  of  an  officer  of  the  naval 
reserve,  and  every  effort  will  be  made  by 
them  to  assist  amateurs  in  solving  the  many 
puzzling  problems  that  arise  in  connection 
with  their  stations. 

It  is  not  necessary  to  enroll  in  the  re- 
serves, to  join  in  the  drill,  but  it  is  earnestly 
hoped  that  all  will  do  so.  So  far  this 
feature  has  been  worked  out  more  com- 
pletely in  the  Middle  West  in  connection 
with  NAT,  the  naval  station  at  Great  Lakes, 
Illinois. 

The  Class  4,  Naval  Reserve,  is  a  very 
liberal  organization,  and  creates  an  oppor- 
tunity that  seems  especially  adapted  to 
amateur  needs.  To  enroll,  you  must  be 
an  American  citizen,  be  able  to  send  and 
receive  at  the  rate  of  ten  words  per  min- 
ute, and  be  able  to  pass  the  usual  physical 
examination.  On  enrollment  members  will 
receive  a  yearly  retainer  fee  of  $12.00,  until 
such  time  as  they  have  perfected  them- 
selves sufficiently  to  be  able  to  handle  their 
work  in  a  manner  on  a  par  with  regular 
naval  practise.  After  such  time  they  will 
receive  an  annual  retainer  pay  equal  to 
two  months'  pay  of  their  corresponding 
grade  in  the  regular  navy.  In  addition 
they  receive  traveling  expenses  to  and  from 
place  of  training — uniforms,  meals  and 
lodging  and  the  regular  pay  from  the  time 
they  leave  their  homes  until  they  return 
to  them.     This   is  all  clear  money,  and 


should  be  particularly  attractive  to  stu- 
dents and  others,  as  it  gives  an  opportunity 
for  training  and  also  saving  during  vaca- 
tion period. 

One  feature  that  is  especially  liberal  is 
that  a  member  of  the  reserves  will  be  dis- 
charged at  any  time  during  peace  at  his 
own  request.  Active  service  is  not  com- 
pulsory, and  orders  to  active  duty  are  only 
issued  at  the  request  of  members  them- 
selves, and  will  be  arranged  so  as  to  inter- 
fere as  little  as  possible  with  your  regular 
business.  The  only  time  the  reserves  can  be 
called  for  active  duty,  is  in  time  of  war, 
and  it  is  intended  to  use  them  at  the  less 
important  land  stations  so  as  to  relieve  the 
regular  officers  and  men  for  their  active 
war  duties.  Information  in  detail  can  be 
secured  from  the  nearest  naval  recruiting 
officer,  who  will  be  glad  to  give  you  any 
information  you  may  require. 

Here  is  an  opportunity  to  prepare  your- 
self so  as  to  be  of  real  assistance  to  the 
Government,  and  at  the  same  time  be  well 
paid  while  doing  so. 

As  it  is  the  first  appeal  to  the  amateur, 
if  we  are  to  live  up  to  the  reputation  that 
has  been  made  for  us  we  should  respond 
gladly  and  willingly.  We  can  assure  you 
that  you  will  be  pleased  with  the  treatment 
you  receive  while  on  active  duty  and  will 
return  home  with  a  much  more  friendly  feel- 
ing towards  "Uncle  Sam"  and  his  navy. 


AN   EXTREMELY  LIGHT-WEIGHT 
RADIO  TRANSMITTER 
AND  RECEIVER. 

The  illustrations  herewith  show  one  ,  of 
the  latest  types  of  portable  light-weight, 
radio  transmitter  and  receiver,  adaptable 
for  both  military  and  civilian  duty. 

This  outfit  was  designed  and  built  by  Mr. 
A.  B.  Cole,  a  prom- 
inent radio  engineer 
of  New  York  City. 
The  transmitter  is 
stationed  in  the  main 
compartment  while 
the  receiving  outfit 
is  placed  in  the  cover 
of  the  case,  which  is 
a  substantially  built 
fiber  affair  measur- 
ing 10  x  10  x  12 
inches.  It  is  equipt 
with  heavy  carrying 
straps.  The  trans- 
mitting set  com- 
prises the  following: 
— A  high  tension 
spark  coil  placed 
within  the  case  and 
w  h  i  c  h  is  used  to 
charge  a  condenser 
thru  a  special 
quenched  spark  gap. 
This  is  seen  on  top 
of  the  panel,  indi- 
•cated  by  the  hori- 
zontal circular  disc. 
This  gap  is  of  the 
quenched  type  and 
is  composed  of  two 
perfectly  parallel 
plates.  The  top 
electrode  is  connect- 
ed to  the  helix  by 
a  flexible  conductor. 
A  special  independ- 
ent vibrator  is  con- 
nected with  the  primary  of  the  induction 
coil  and  this  is  located  behind  the  forward 
binding  posts.  It  is  an  essential  feature 
that  the  frequency  of  the  emitted  wave  have 


a  high  pitch,  musical  tone  and  with  the  aid 
of  this  vibrator  this  is  readily  accomplished, 
which  was  heretofore  impossible,  due  to 
forced  action  of 
the  spring  con- 
stituting the  com- 
mon form  of  vi- 
brator. 


The  tuning  inductance  consists  of  a  num- 
ber of  turns  of  wire  placed  on  a  frame,  the 
size  of  which  is  equivalent  to  that  of  the 
inside  of  the  dimensions  of  the  box,  so  that 


it  does  not  interfere  with  any  of  the  other 
inclosed  instruments.  Taps  are  led  off  at 
four  different  positions,  and  are  termi- 
nated in  four  plug 
receptacles  which 
are  placed  at  the 
left  of  the  panel. 
A  flush  type  hot 
wire  ammeter  is  also 
secured  to  the 
Bakelite  control 
panel.  The  antenna 
change-over  switch 
is  shown  in  the 
background  and  the 
transmitter  key  at 
the  right. 

The  receiving  ap- 
paratus is  mounted 
on  a  separate 
Bakelite  panel  and 
contained  in  the  case 
as  illustrated.  This 
receiver  comprises 
an  inductive  coupler, 
with  a  fixt  secondary 
and  tuning  is  ac- 
complished by  means 
of  a  secondary  vari- 
able capacity.  This 
latter  is  controlled 
by  means  of  a  grad- 
uated handle  noted 
at  the  upper  right 
hand  corner.  An  en- 
closed mineral  detector  is  employed  with  this 
set;  it  is  placed  in  the  center  of  the  cabinet. 
The  round  instrument  below  the  detector  is  a 
high  frequency  buzzer  used  for  testing  pur- 
poses, and  the  button  directly  beneath  the 
buzzer  is  used  to  start  the  buzzer.  The  plug 
to  the  left  of  the  push  button  inter-connects 
the  telephones  with  the  set,  while  the  plug  to 
the  right  interlinks  the  antenna  and  ground 
thru  the  sending  apparatus.  The  switch  to 
the  left  of  the  sending  key  connects  the  an- 
tenna with  either  the  sending  or  receiving 
instruments ;  by  turning  to  the  left,  the  re- 
ceiving instruments  are  connected,  and  to 
the  right  is  for  transmitting. 


One  of  the  Latest  Compact 
Radio  Sets  Designed  Espe- 
cially for  Field  Military  Ser- 
vice. It  Has  a  Powerful 
Transmitter  Operating  on  a 
Storage  or  Dry  Battery. 


July,  1917 


THE  ELECTRICAL  EXPERIMENTER 


201 


Amateur  and  Experimental  Radio  Research 


PART  I. 

OF  all  the  present-day  fields  of  sci- 
entific endeavor,  there  is  probably 
none  more  promising  or  produc- 
tive than  that  of  wireless.  It  is 
hardly  correct  to  say  that  wireless 
is  in  its  infancy,  but  the  art  has  by  no 
means  reached  any  reasonable  degree  of 
perfection  and  the 
work  yet  to  be  done 
is  unbelievably  vast 
and  important. 

Of  the  multitude  of 
wireless  amateurs  in 
the  United  States, 
there  is  a  surprisingly 
small  number  of  se- 
rious-minded experi- 
menters who  have 
really  entered  the  field 
for  anything  more 
than  an  interesting 
hobby.  Many  experi- 
menters are  inclined 
to  think  that  wireless 
research  entails  such 
a  great  expense  and 
involves  such  costly 
apparatus  that  it  is 
quite  beyond  their 
means.  It  is  the  pur- 
pose of  this  paper  to 
disprove  this  errone- 
ous opinion  and  ex- 
plain how  it  is  possible 
for  every  amateur  to 
exercise  his  inventive 
talent  in  the  great 


By  RAYMOND  FRANCIS  YATES 

member  that  the  application  of  wireless  is 
not  necessarily  limited  to  the  transmission 
of  intelligence.  In  the  future  this  will  con- 
stitute the  smallest  part  of  it.  We  have 
seen  the  birth  of  developments  that  tell 
us  in  no  uncertain  terms  that  the  science 
of  radio  is  destined  to  play  a  far  greater 
part  in  the  life  of  the  world  than  it  does 


If  You   Make   Up   Loading   or  Other  Induc- 
tances, Take  the  Trouble  to  Either  Measure 
or  Calculate  the  Inductance  in  Micro-Henrys 
or  Centimeters.     It  Always  Pays. 

field  of  radiocommunication.  There  seems 
to  be  a  lack  of  real,  scientific  enthusiasm 
among  the  amateurs  of  the  United  States, 
especially  in  regard  to  the  perfection  of  the 
art,  and  it  is  the  object  of  the  author  to 
try  and  offer  a  few  suggestions  with  the 
hope  that  these  amateurs  will  regard  their 
work  in  a  more  serious  attitude  with  the 
intention  of  developing  something  original. 
I  have  talked  to  many  experimenters  who 
thought  that  they  had  conceived  a  valuable 
idea,  but  either  they  did  not  possess  the 
courage  to  develop  it  or  they  thought  it 
was  beyond  their  ability.  If  de  Forest  had 
had  the  same  attitude,  we  would  not  have 
the  Audion  ;  if  Alarconi  had  lacked  unflinch- 
ing inspiration  and  courage,  probably  de 
Forest  would  not  have  needed  to  invent 
his  Audion  detector  at  all.  Among  the 
400,000  and  more  radio  experimenters  in 
the  United  States,  there  are  undoubtedly 
many  Fessendens,  Marconis  and  de  Forests, 
who  either  lack  courage  or  enthusiasm  to 
enter  research  work. 

Possibilities  of  the  Field. 

The  possibilities  of  development  in  wire- 
less are  limitless.  We  have  just  entered  a 
new  era — the  Wireless  Era.    We  must  re- 


A  Typical  Radio  Experimental  Laboratory  Equipt  with  a  Variety  of  Condensers  and 
Inductances,  as  Well  as  Other  Supplementary  Apparatus  with   Which    Many  Valuable 

Researches  Can  Be  Made. 

today.  The  wireless  transmission  of 
power,  radio  control  of  mechanisms  (radio 
tele-mechanics),  the  development  of  radio- 
telephony,  directive  communication,  the 
perfection  of  the  high  frequency  alternator, 
and  the  elimination  of  interference,  are  but 
a  few,  a  very  few,  of  the  problems  to  be 
solved.  There  will  be  a  day,  in  the  not 
far  distant  future,  when  an  audience  in 
New  York  may  sit  and  listen  to  a  concert 
being  played  in  Paris  •  via  radio.  Nikola 
Tesla  tells  us  that  within  25  years  we  will 
be  sending  radio  controlled  boats  to  airs- 
port  of  Europe  without  a  man  on  board ! 
We  may  put  much  faith  in  statements  made 
by  Tesla,  as  his  accomplishments  are  many 
and  great.  If  it  is  possible  to  control  ves- 
sels via  radio,  why  will  it  not  become  pos- 
sible to  control  airships,  trains  and  auto- 
mobiles? It  would  indeed  be  a  superficial 
observer  who  would  conclude  that  radio  is 
anything  but  a  fruitful  field  for  those  who 
desire  to  enter  irrto  penetrating  and  pro- 
ductive investigation. 


Knowledge  Necessary  for  Research  Work. 

Contrary  to  the  general  opinion  possest 
by  experimenters,  it  is  next  to  impossible 
to  successfully  enter  into  research  work 
without  an  elementary  understanding  of 
the  fundamental  principles  of  radiocom- 
munication. It  is  indeed  a  deplorable  fact 
that  70  per  cent  of  the  radio,  experimenters 
in  the  United  States 
can  not  thoroly  ex- 
plain the  theoretical 
basis  of  operation  of 
one  of  their  instru- 
ments. True,  they 
can  tell  you  that  a 
variable  condenser  is 
used  to  tune  with  and 
to  reduce  "static,"  but 
the  real  "how"  of  its 
operation  is  hopelessly 
beyond  them.  These 
statements  do  not 
necessarily  infer  that 
to  enter  research  work 
it  is  imperative  that 
one  be  a  radio  expert 
or  graduate  engineer. 
Quite  to  the  contrary. 
It  is  only  necessary 
that  one  be  familiar 
with  the  elementary 
theory  under  which 
the  various  elements 
of  radio  receptors  and 
transmitters  operate. 
This  knowledge  is  ab- 
solutely essential  and 
even  then  it  is  not 
necessary  to  go  real  deep  at  the  start.  It 
is  not  necessary  to  be  able  to  explain  in 
theoretical  detail  the  unilateral  conductivity 
of   crystal   rectifiers  or  the  mathematical 


A  Good  Type  of  Experimental  Radio  Trans- 
mitter Which  May  be  Used  with  a  Phantom 
or  "Dummy"  Antenna. 


The  Radio  Student  and  Investigator  Should 
Provide  Himself  With  a  Number  of  Variom- 
eters of  Different  Sizes  and   Known  Induc- 
tance Values. 

physics  of  the  expanding  hot-wire  meter. 
One  should  be  familiar,  however,  with  in- 
ductance, capacity,  resonance,  damping, 
resistance,  impedance,  etc.  One  should 
know  ivhy  a  variable  condenser  will  alter 
the  wave  length  by  changing  the  capacity 
of  the  circuit;  why  the  inductance  of  a 
tuning  transformer  has  the  same  effect, 
and  why  the  quenched  gap  has  a  tendency 
to  set  up  sustained  oscillations.  It  is  sur- 
prising how  many  suggestions  present  them- 
selves when  a  working  knowledge  of  the 
various  instruments  is  acquired.  Ideas  then 
come  fast  and  numerous.  The  moral  here 
is — study !  Read  every  article  and  book 
you  can  get  hold  of.  If  you  don't  under- 
stand it  the  first  time,  read  it  again.  It 
would  probably  take  you  several  years  to 
work  out  the  law  of  W.  L.  =  59.6  V  L  X  C  , 
but  by  reading  the  up-to-date  magazines  on 
the  subject  and  elementary  books  such  as 
the  "Wireless  Course"  by  Gernsback,  Les- 
carboura  and  Secor,  you  can  learn  just 
why,  for  a  given  wave  length,  that  when 
C  is  decreased,  L  must  be  increased,  etc. 
None  are  so  blind  as  those  who  won't  seel 
(Continued  on  page  218) 


202 


THE  ELECTRICAL  EXPERIMENTER 


July,  1917 


A  PECULIAR  EXPERIMENT  WITH 
A  LAMP  BULB. 

A  curious  experiment  can  be  made  with 
a  110  volt,  16  candle  power  carbon  lamp. 
Anyone  who  has  seen  the  tip  broken  off 
an  electric  lamp  while  burning  has  noticed 
that  it  soon  becomes 
brilliant,  then  goes  out. 

For  this  paradoxical 
experiment,  now  break 
the  tip  A  off  as  small 
as  possible,  but  enough 
to  let  the  air  in,  then  fill 
up  to  B  with  gasoline. 
Connect  the  lamp  in 
circuit  to  110  volts,  and 
the  lamp  will  b  u  r  n 
about  y2  candle  power. 
Now,  tho  this  is  only 
a  110  volt  lamp  and  or- 
dinarily in  perfect  con- 
dition, it  would  burn 
out  in  a  very  short 
time  on  a  220  volt  cir- 
cuit ;  connect  it  to  a  220  volt  circuit,  and  it 
will  apparently  burn  at  the  same  candle 
power  or  l/2.  When  the  lamp  has  burned 
for  about  three  minutes  on  either  voltage, 
place  a  match  at  the  opening  and  a  small 
and  very  white  light  will  burn  like  a  candle, 


MILITARY  SIGNAL  LIGHT  AND 
BUZZER. 

A  very  compact  and  serviceable  arrange- 
ment of  military  signal  light  and  tell-tale 
buzzer  is  shown  in  the  accompanying  illus- 
tration.     It    was    developed    by    R.  C. 


The  Boy  Scout  S 
Light  Outfit  Very 


ignal  Corps  Divisions  Will   Find  This  Combined  Buzzer  and  Signal 
Light  and  Serviceable.     Be  Sure  You  Have  a  Good  Lens  to  Start 
With,  and   a    Parabolic,   Well   Polished  Reflector. 


A  Novel  Experiment  with  an  Incandescent 
Lamp  Which  Is  Filled  Up  to  "B"  with  Gaso- 
line. When  Connected  to  Live  Circuit  Gas 
Is  Generated  and  May  Be  Ignited  at  A  by 
a  Match. 

becoming  stronger  as  long  as  the  gasoline 
lasts,  same  depending  on  the  size  of  the 
tip,  but  as  soon  as  you  open  the  switch, 
the  light  and  flame  go  out. 

Place  the  lamp  in  a  horizontal  position 
and  the  lamp  acts  the  same  as  tho  you  had 
broken  the  tip  while  it  was  burning.  It 
will  only  behave  in  this  paradoxical  manner 
while  vertical,  tip  up  and  base  down. 

Contributed  bv 

GEORGE  C.  MACLEAN. 


FORMULA  FOR  WOOD'S  METAL. 

This  silvery  fine-grained  alloy  fuses  .be- 
tween 151  and  162  deg.  Fah.,  and  is  adapted 
to  soldering,  and  mounting  crystals  as 
galena,  silicon,  etc.,  for  wireless  work. 

Tin  2  parts 

Lead   4  parts 

Bismuth   5  to  8  parts 

Contributed  bv 

ALBERT  W.  WILSDON. 

Due  to  the  advent  of  the  war,  we  are 
particularly  desirous  of  obtaining  manu- 
scripts describing  original  and  practical 
"  Electrical  Experiments." 


Avery,  and  is  said  by  him  to  be  particu- 
larly efficacious  for  flashing  light  signals 
at  night ;  the  tell-tale  buzzer  sounding  for 
each  dot  and  dash  as  they  are  sent  out  by 
the  transmitting  key  or  switch  on  the  side 
of  the  battery  case. 

This  idea  should  prove  very  useful  to 
the  signal  corps  division  of  the  Boy  Scouts. 
The  present  signaling  device  was  found 
very  efficacious  compared  to  the  acetylene 
lantern  previously  used  in  the  United 
States  Army  signaling  work,  the  electric 
lantern  here  illustrated  having  signaled 
over  a  distance  of  5  miles  at  night  and 
2  miles  in  daylight. 

The  instrument  as  developed  by  its  in- 
ventor measures  10;  '2  inches  in  length  by 
2J4  inches  extreme  diameter.  The  trans- 
mitting key  folds  over  so  that  when  car- 
ried in  the  pocket  it  cannot  accidentally 
close  the  circuit. 


AN    ELECTRIC   BIRTHDAY  CAKE 
WITHOUT  THE  DOUGH. 

The  materials  required  for  this  stunt  are 
a  tin  pan,  about  ten  inches  in  diameter  and 
four  inches  high,  a  number  of  miniature- 
base  colored  lamps,  and  a  source  of  cur- 
rent. After  obtaining 
these,  proceed  as  fol- 
lows : 

Mark  off  on  the  bot- 
tom of  the  tin  pan, 
the  desired  positions  of 
the  lamps,  and  punch 
holes,  H,  at  these 
points.  The  holes  must 
be  of  such  size  that  the 
screw  base,  C,  of  the 
lamps,  L,  will  just  fit  in 
them.  This  done,  turn 
the  pan  over  and  solder 
the  No.  20  wires,  M,  to 
all  the  center  connec- 
tions of  the  lamps,  and 
continue  this  wire  to 
current,   which  may  be  a 


HOLY  SMOKE!  ANOTHER 
ELECTRIC  ALARM  CLOCK. 

The  illustration  shows  an  electrically  op- 
erated alarm  clock  of  new  design.  One 
terminal  of  the  battery  is  connected  to  a 
metal  standard,  holding  a  brass  pulley,  on 
which  is  wound  a  few  turns  of  fine  copper 
or  brass  wire.  One  end  of  the  wire  is  fast- 
ened to  a  piece  of  cord,  the  other  end  of 
which  is  tied  to  the  alarm  winding  key. 
The  second  terminal  of  the  battery  is  con- 
nected thru  a  bell  to  one  foot  of  the  alarm 
clock. 

The  mode  of  operation  is  as  follows : 
The  circuit  is  open  at  the  cord  due  to  its 
non-conductivity.  When  the  alarm  rings, 
it  winds  the  cord  on  it  until  the  wire  is 
drawn  on  to  the  key.  This  completes  the 
circuit  and  operates  the  bell  or  any  other 
device.    The  magnet  wire  is  of  course  long 


Chech  spring 


Alarm 
clocA 


What!  Ding-bust-it,  if  Here  Ain't  Another 
"Electric"  Alarm  Clock.  The  Inventor  Ar- 
ranges a  String  and  Wire  So  That  When 
Clock     Key    Turns,    the    Wire     Is  Finally 

Grounded,  Closing  the  Bell  Circuit- 
enough  so  that  when  the  alarm  key  has 
turned  its  full  rotation  there  is  still  some 
wire  wound  around  the  pulley.    Both  the 


the  source  of 

flashlight  battery  or  two,  B,  placed  under 
the  pan.  If  the  source  of  current  is  a 
storage  battery  or  a  step-down  transformer, 
the  wires  going  to  the  same  should  be  con- 
cealed. The  hardest  part  of  the  work  is 
now  finished. 

The  icing  is  now  to  be  put  on  the  "cake" 
and  in  order  to  make  it  stick,  paper  should 
be  pasted  on  the  pan.    The  icing  is  spread 


For    Birthday   Parties   an    Electric  Cake 
Always  Welcome.    This  One  Is  Made  from 
a  Tin  Pan  Iced  Over.    The  Battery  Is  Placed 
Within  the  Pan. 

smoothly  over  the  paper  up  to  and  touching 
the  lights.    When  hardened,  this  novelty 
will  have  all  the  appearances  of  a  genuine 
iced  cake  with  lights  mounted  in  the  top. 
Contributed  by  VICTOR  DE  FLORIN. 

clock  and  the  standard  should  be  securely 
fastened  to  a  suitable  baseboard. 
Contributed  by  A.  H.  BEILER. 

TO  TRANSFER  PICTURES  TO 
WOOD. 

Dissolve  salt  in  soft  water ;  float  your 
photo  print  on  the  surface,  picture-side  up; 
let  it  remain  about  an  hour.  The  wood 
should  be  of  bird's-eye  maple,  or  other 
light-colored  hardwood.  Varnish  with  the 
best  copal  or  transfer  varnish. 

Take  the  picture  from  the  water ;  dry  a 
little  between  linen  rags  ;  then  put  the  en- 
graving, picture  side  down,  on  the  varn- 
ished wood,  and  smooth  it  nicely.  If  the 
picture  entirely  covers  the  wood  after  the 
margin  is  cut  off,  so  that  no  varnish  is 
exposed,  lay  over  it  a  thin  board  and  heavy 
weight ;  leave  it  thus  over  night.  If  you 
wish  but  a  small  picture  in  the  center  of 
the  wood,  apply  the  varnish  only  to  a  space 
the  size  of  the  picture.  Dip  your  forefinger 
in  salt  and  water,  and  commence  rubbing 
off  the  paper ;  the  nearer  you  come  to  the 
picture,  the  more  careful  you  must  be,  as 
a  hole  would  spoil  your  work. 

Contributed  by       V.  C.  McILVAINE. 


July,  1917 


THE   ELECTRICAL  EXPERIMENTER 

Experimental  Chemistry 

By  ALBERT  W.  WILSDON 


203 


HYDROCHLORIC  ACID. 

BASIL  VALENTINE  in  the  15th 
Century  first  described  the  prepara- 
tion by  a  process  similar  to  the 
one  now  in  use.  He  called  it 
"Spirit  of  Salt."  That  which  es- 
caped from  anything'  easily  in  intangible 
form  was  called  a  "Spirit."    Thus  Spirit 


Experimental  Apparatus  Set  Up  for  the  Preparation  of  Hydrochloric 
Acid   in   the  Laboratory. 

of  Wine,  Spirit  of  Wood,  etc.,  are  indica- 
tion of  the  crude  theory  of  spirits  so  long 
in  vogue.  Hydrochloric  acid  being  a  gas 
which  is  liberated  from  salt  when  it  is 
treated  with  Sulfuric  acid,  it  was  naturally 
regarded  as  a  Spirit  of  Salt. 

Glauber  prepared  this  gas  in  the  17th 
Century  by  treating  Sodium  Chlorid  [Com- 
mon salt,  Na  CI]  with  sulfuric  acid. 

Priestly,  in  1772,  first  obtained  it  in  pure 
condition.    He  called  it  "Marine  Acid  Air." 

Upon  the  theory  introduced  by  Lavoisier, 
that  all  acids  necessarily  contain  oxygen, 
Hydrochloric  acid  was  for  a  long  time  be- 
lieved to  contain  oxygen. 

About  1810,  Davy  established  the  ele- 
mentary nature  of  Chlorin,  and  hence  the 
true  nature  of  its  hydrogen  compound,  Hy- 
drogen Chlorid  [Hydrochloric  acid].  The 
correctness  of  his  results  became  generally 
recognized  shortly  after.  Many  facts  lead 
to  the  conclusion  that  Hydrochloric  acid 
gas  is  composed  of  Hydrogen  and  Chlorin 


Th/stle  tube- 
Deli  very  tube 


rig.  70 


Fig.71 


At  Left— A  Wolff  Bottle  With  Three  Neck': 
At  Right — Erlenmeyer  Flask  Which  May  Be 
Substituted  for  the  Florence  Flask  Specified. 


Fourteenth  Lesson 
in  such  a  ratio  that  its  composition  may  be 
represented  by  the  formula,  HC1. 

1.  Hydrogen  burns  in  chlorin,  the  only 
product  being  Hydrochloric  acid  gas. 

2.  When  hydrogen  chlorid  [Hydrochloric 
acid]  is  decomposed  by  an  electric  cur- 
rent, equal  volumes  of  hydrogen  and  chlorin 
are  evolved. 

3.  When  a  mixture 
of  equal  volumes  of 
hydrogen  and  chlorin 
is  exposed  to  the  di- 
rect sunlight,  or  to  the 
action  of  an  electric 
spark,  the  gases  com- 
bine w  i  t  h  explosive 
violence,  and  Hydro- 
chloric acid  gas  is 
formed  with  no  resi- 
due. Furthermore,  the 
volume  of  the  result- 
ing gas  equals  the 
sum  of  the  volumes 
of  hydrogen  and 
chlorin  used. 

4.  When  a  given 
volume  of  dry  hydro- 
c  h  1  o  r  i  c  acid  gas  is 
treated  with  sodium 
amalgam,  the  chlorin 
is  withdrawn  by  the 
sodium  in  the  amal- 
gam, and  a  volume  of 
hydrogen  remains 
which  is  half  the  orig- 
inal volume. 

5.  No  derivative  of 
Hydrochloric  acid  is 
known  which  contains 
less  hydrogen  or  less 
chlorin  in  a  molecule. 

6.  The  ratio  by  weight  in  which  hydrogen 
and  chlorin  combine  is  1  to  33.45.  Hence, 
the  lowest  molecular  weight  of  Hydro- 
chloric acid  is  36.45,  a  number  which  has 
been  verified  by  several  different  methods. 
Occurrence : 

The  free  occurrence  of  Hydrochloric  acid 
in  Nature  is  rare,  as  its  affinities  are  too 
strong.  It  occurs  from  the  exhalations  of 
active  volcanoes,  as  Vesuvius  and  the 
fumaroles  of  Hecla.  It  is  also  a  constitu- 
ent of  some  streams  and  rivers  which 
have  their  origin  in  volcanic  mountains. 
It  is  found  in  the  waters  of  certain  South 
American  rivers  that  have  their  source  in 
the  volcanic  districts  of  the  Andes. 

The  series  of  salts,  derived  from  Hy- 
drochloric acid,  are  widely  distributed  and 
of  great  importance.  In  general,  they  are 
crystalline,  stable,  and  soluble  [except  Sil- 
ver], tho  some  are  decomposed  by  water, 
especially  if  evaporated  with  it.  Common 
salt,  Sodium  Chlorid  [NaCl]  is  the  most 
important  of  the  chlorids,  and  in  fact  is 
the  parent  substance  from  which  almost 
all  chlorin  and  its  compounds  are  made, 
as  well  as  all  of  the  sodium  compounds. 

In  the  manufacture  of  Sodium  Car- 
bonat  by  the  process  in  most  common  use, 
Salt  is  first  treated  with  Sulfuric  acid, 
by  which  it  is  converted  into  Sodium  Sul- 
fate. In  this  stage  of  the  process,  Hydro- 
chloric acid  is  necessarily  formed  in  large 
quantity.  Formerly  this  was  allowed  to 
escape  into  the  air,  but  the  injurious  ef- 
fects which  it  had  upon  vegetation,  caused 
laws  to  be  enacted  whereby  the  manu- 
facturers were  compelled  to  prevent  the 
escape  of  this  gas.  The  waste  gases  arc 
now  caused  to  pass  thru  towers  filled  with 
bricks  so  arranged  as  to  present  a  maxi- 
mum of  surface,  over  which  water  is  kept 
constantly  passing.  The  gas  dissolves  in 
the  water  quite  readily,  and  the  solution 


thus  obtained,  which  is  sometimes  some- 
what colored,  is  the  Hydrochloric  or  Muri- 
atic acid  of  commerce.  The  discoloration 
is  due  to  the  presence  of  impurities,  such 
as  Iron  and  organic  substances. 

Hydrochloric  acid  forms  a  part  of  the 
digestive  fluids  of  the  stomach.  The  acid 
is  supposed  to  be  secreted  in  what  is  known 
as  the  Border   Cells,  whose  exact  func- 


Method   of  Collecting    Hydrochloric   Gas  By 
the  Downward   Displacement  in  a  Dry  Test 
Tube.     See  Experiment  79. 

tions  are  still  unknown.  The  gastric  juices 
of  the  stomach  in  normal  condition  con- 
tain about  0.33  per  cent  of  free  acid. 
Aside  from  the  aid  which  Hydrochloric 
acid  gives  in  peptic  digestion,  its  presence 
is  important,  in  that  it  destroys  the  germs 
of  fermentation  and  disease,  and  probably 
dissolves  some  mineral  salts.  Its  action 
in  destroying  germs  permits  the  food  to  be 
stored  in  the  stomach  for  some  time  with- 
out undergoing  decay. 
Preparation  : 

The  method  generally  used  in  the  labora- 
tory is  to  treat  common  salt,  Sodium 
Chlorid  [NaCll  with  Sulfuric  acid.  The 
reactions  which  may  take  place  are : 

[1] 


[2] 


NaCl  +  H,S04  =  HC1  +  NaHSCn 
Sodium  Sulfuric  Hydrochloric  Hydrogen 
Chlorid        Acid  Acid  Sodium 

Sulfate 

2NaCl  +  H.SO,  =  2HC1  -f  Na=SO, 
Sodium  Sulfuric         Hydro-  Sodium 

Chlorid  Acid  chloric  Sulfate 

Acid 

If  an  excess  of  acid  is  employed,  as  in 


Fit].  72 


Me/hoc/  cf  cutting 
rubber  connector 


F>9  73  Q 


Shape  of  Glass  Tubes  Used  to  Connect  Up 
the  Apparatus  Here  Illustrated  and  Method 
of    Cutting    Rubber    Sleeves    Diagonally  to 
Make  Them  Slip  On  Tubes  Easier. 

the  first  reaction,  a  moderate  heat  is  re- 
quired, and  a  readily  soluble  salt,  Hydrogen 
(Continued  on  page  220) 


204 


THE  ELECTRICAL  EXPERIMENTER 


July,  1917 


Wrfipklesi 


EDITED  BY  S.GERNSBACK 

Under  this  heading  we  will  publish  every 
month  useful  information  in  Mechanics, 
Electricity  and  Chemistry.  We  shall  be 
pleased,  of  course,  to  have  our  readers  send 
us  any  recipes,  formulas,  wrinkles,  new 
ideas,  etc.,  useful  to  the  experimenter  which 
will  be  duly  paid  for,  upon  publication,  if 
acceptable. 


HOW  TO  MAKE  A  CHEMICAL 
BALANCE. 

The  accompanying  photo  illustrates  a 
chemical  balance  constructed  by  the  writer 
While  not  being  extremely  accurate  it 
nevertheless  will  measure  quantities  to  the 
degree  of  accuracy  generally  demanded  in 
an  amateur's  shop  or  laboratory.  It  is  not 
difficult  to  construct  and  ordinary  care  be- 
ing used,  it  can  be  made  to  weigh  within  a 
gram. 

The  illustration  is  self-explanatory,  but 
a  few  words  may  not  be  amiss.  To  make 
it,  first  obtain  a  telephone  ringer  set  as  that 
shown  in  figure.  It  is  not  necessary  to  pur- 
chase a  brand  new  one,  but  go  to  some 
electric  or  telephone  repair  shop  where  you 
may  secure  a  ringer  for  less  than  fifty 
cents  or  even  for  nothing,  possibly.  Pro- 
ceed to  rearrange  the  different  pieces  so  as 
to  appear,  after  adding  other  parts,  like 
that  shown  below.  On  the  armature, 
solder  or  bolt  a  strip  of  metal,  preferably 
aluminum,  1 2"  x  7"  and  on  the  ends  of  this 
"beam"  attach  two  circular  4"  pans.  Be- 
low one  of  the  pans  place  a  right  angle 
strip  and  adjusting  screw,  in  order  to  be 
able  to  make  pans  balance.  Back  of  the 
instrument,  after  fixing  on  base,  place  a 
strip  for  an  indicator. 


Every  Experimenter  Needs  a  Small  Balance 
for    Weighing    Chemicals    On.      Here's  One 
Made  from  a  Telephone  Ringer  Frame  Fitted 
with  a  Set  of  Pans  and  a  Scale. 

Finished  with  shellac,  this  instrument 
will  make  a  neat  looking  and  useful  little 
piece  of  apparatus  for  chemical  or  photo- 
graphic work. 

Contributed  by  MARK  SLABODNIK. 


1  per  cent  to  50  per  cent,  based  on  the 
weight  of  one  gallon  of  water  at  40°  F. 
=  8.33888  lbs.  [avoirdupois],  or  one  fluid 
ounce  of  water  weighing  456.03  grains 
[avoirdupois] . 
For  each  fluid  ounce  of  water  take 


For  a  1  per  cent  solution 


2 

9.38 

3 

..  14.10 

4  " 

. .  19.00 

5  " 

"     . .  24.00 

6  " 

"     . .  29.10 

7  " 

"     . .  34.30 

8  " 

"     . .  39.60 

9  " 

"     . .  45.09 

10  " 

"     . .  50.67 

15  " 

"     . .  80.48 

20  " 

"     ..  114.00 

25  " 

"      ..  152.00 

30  " 

"      ..  195.44 

35  " 

"     . .  245.56 

40  " 

"     ..  304.02 

45  " 

"     ..  373.10 

50  " 

"     ..  456.03 

4.66  grains 


It  should  be  noted  that  the  above  table 
applies  to  water,  percentage  solutions  for 
other  liquids  would  necessarily  have  to  be 
figured  on  the  weight  of  the  particular 
liquid. 

Percentage  solutions  are  also,  sometimes, 
made  up  from  a  saturated  base.  This 
method  is  incorrect  unless  it  is  so  desig- 
nated in  giving  the  formula,  that  is,  by 
stating  in  the  formula  saturated  solution 
base.  Such  percentages  are  made  by  plac- 
ing in  the  liquid  used  more  of  the  chem- 
ical than  the  liquid  will  carry  in  solution ; 
this  resulting  solution  is  filtered  to  re- 
move the  excess  chemical  and  then  used 
as  a  base.  For  example,  to  make  a  10 
per  cent  solution,  10  per  cent  of  the  base 
is  used  and  90  per  cent  of  the  pure  liquid, 
or  in  other  words,  1  ounce  of  the  saturated 
solution  to  9  ounces  of  the  liquid. 

Contributed  by  ALBERT  W.  WILSDON. 


TO  PETRIFY  WOOD. 

Equal  quantities  of  gem  salt,  rock  alum, 
white  vinegar,  chalk  and  Peebles'  powder. 
This  solution  will  petrify  wood  or  any  other 
porous  substances  if  put  in  after  the  ebul- 
lition is  over. 

A  Stone  Coating  for  Wood :  Forty  parts 
chalk,  fifty  of  resin,  four  of  linseed  oil, 
melted  together;  to  this  should  be  added 
one  part  of  oxid  of  copper  and  then  one 
part  of  sulfuric  acid.  This  last  should  be 
added  very  carefully.  Apply  with  a  brush 
while  hot. 

To  Imitate  Dark  Woods :  The  appearance 
of  walnut  may  be  given  to  white  woods 
by  painting  or  sponging  with  a  concen- 
trated warm  solution  of  permanganat  of 
potassium.  The  effect  varies  for  differ- 
ent kinds  of  woods,  some  becoming  stained 
rapidly,  others  requiring  more  time.  When 
stained  wash  thoroly  with  soft  water.  After 
the  wood  has  dried  it  may  be  varnished, 
and  will  be  found  to  very  closely  resemble 
the  natural  dark  woods. 

To  Polish  W ood :  Only  a  very  few  ex- 
perimenters who  make  their  own  cabinets 
know  how  to  put  a  good  polish  on  their 
woodwork.  The  following  is  a  very  good 
method.  Take  a  piece  of  pumice  stone  and 
water,  and  pass  regularly  over  the  work 
until  the  rising  of  the  grain  is  cut  down; 
then  take  tripoli  and  boiled  linseed  oil, 
and  polish  to  a  bright  surface. 

Contributed  by      V.  C.  McILVAINE. 


"PER  CENT"  SOLUTIONS. 

A  table  giving  the  weight  in  grains 
[avoirdupois]  of  any  chemical  substance 
required  to  make  a  per  cent  solution  from 


HOW  TO  MAKE  A  HYGROMETER. 

The  hygrometer  is  an  instrument  to 
measure  the  degrees  of  dryness  or  mois- 
ture of  the  atmosphere.  There  are  various 
kinds  of  hygrometers;  for  whatever  body 


either  shrinks  or  swells  by  dryness  or 
moisture,  is  capable  of  being  formed  into 
an  hygrometer,  such  as  woods  of  most 
kinds,  particularly  ash,  deal,  poplar,  etc. 
The  following  is  the  most  lasting  and  con- 
venient mode  of  construction  for  an  in- 
strument of  this  description. 

Take  a  very  fine  balance,  and  place  in 
it  a  sponge,  or  other  body  which  easily 
absorbs  moisture,  and  let  it  be  in  equilib- 
rium with  a  weight  hung  at  the  other  end 


/ 

tj^jDampwtaflier 

0  1 

^^^^ 

y%\pry  waif  her 

if  %  K\ 

© 

mm 

A  Simple  Hygrometer  Which  Can  Be  Made 
at  a  Cost  of  a  Few  Cents,  from  a  Sponge, 
a  Paper  Scale  and  a  Lightly  Pivoted  Lever. 

of  the  beam.  If  the  air  becomes  moist, 
the  sponge,  becoming  heavier,  will  prepon- 
derate ;  if  dry,  the  sponge  will  be  raised 
up.  This  balance  may  be  contrived  in  two 
ways,  by  either  having  the  pin  in  the  mid- 
dle of  the  beam,  with  a  slender  tongue, 
a  foot  and  a  half  long,  pointing  to  the  di- 
visions of  an  arched  plate,  fitted  on  it,  or 
the  other  extremity  of  the  beam  may  be 
so  long,  as  to  describe  a  large  arc  on  a 
board  placed  for  the  purpose. 

To  prepare  the  sponge,  it  may  be  neces- 
sary to  wash  it  in  water  and,  when  dry,  in 
water  or  vinegar,  in  which  sal  ammoniac 
or  salt  of  tartar  has  been  dissolved  and 
let  it  dry  again ;  then  it  is  fit  for  use.  The 
instrument  can  be  hung  against  the  wall; 
and,  in  that  case  a  bit  of  steel,  as  at  "A," 
should  be  placed  before  the  needle,  to  keep 
it  straight. 

Contributed  by     WILL  M.  DUFFIE. 


COLD  SOFT  SOLDER. 

Everyone  at  sometime  or  other  has  had 
occasion  to  solder  two  pieces  of  metal, 
which  because  of  their  composition,  or  be- 
cause of  attached  parts,  could  not  be  raised 
to  the  temperature  that  even  soft  solder 
flows  at.  The  following  solder  meets  that 
demand,  as  it  can  be  used  without  heat. 

Precipitate  some  copper  from  a  copper 
solution,  such  as  copper  sulfate  or  copper 
nitrat  by  means  of  zinc  or  iron  filings. 
Into  a  mortar  pour  some  mercury  and  the 
copper  precipitate.  Add  a  few  drops  of 
dilute  sulfuric  acid  and  grind  until  the  cop- 
per has  united  with  the  mercury.  Wash' 
the  amalgam  with  water  till  bright  and 
clean.  Put  into  a  cloth  to  dry  and  by  means 
of  a  twisting  motion,  like  grapes  are 
strained,  squeeze  out  the  excess  of  mercury 
until  the  copper  amalgam  is  just  workable 
by  the  fingers.  Rub  well  into  the  surfaces 
to  be  joined,  and  press  together  over  night. 
Some  of  the  mercury  penetrates  the  sur- 
faces, and  some  of  the  copper  crystallizes 
out,  and  the  compound  becomes  very  hard. 
Strange  to  say,  this  compound  is  silver 
white.  By  using  more  mercury,  a  pliable 
metal  is  obtained  that  hardens  slowly.  If 
the  solder  is  too  hard,  grind  up  with  more 
mercury.  Keep  gold  and  silver  jewelry, 
etc.,  out  of  the  way,  as  mercury  destroys 
them. 

Contributed  by        H.  V.  PFEIFFER. 


July,  1917 


THE   ELECTRICAL  EXPERIMENTER 


205 


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Here  is  your  chance  to  win  a  cash  prize  for  a  few  minutes'  brain  work.  The  big  question  now  confronting  every  radio 
amateur  is— "What  can  I  do  with  my  wireless  apparatus?"  To  help  the  more  than  400,000  loyal  radio  students  and  en- 
thusiasts to  apply  their  knowledge  and,  most  important  of  all,  to  utilize  their  instruments  for  some  practical  electrical  or 
communication  purpose  other  than  wireless,  we  shall  pay  two  prizes— one  of  $10.00  and  one  of  $5.00  respectively,  for  the 
best  suggestion  as  to  "what  to  do  with  your  radio  set  during  the  war."  Be  brief;  100  to  200  words  should  tell  your  story, 
Remember— it's  the  "idea"  that  counts.  Get  busy  at  once,  boys,  as  we  want  all  suggestions  in  by  July  25th,  at  the  latest,  so  that 
the  results  can  be  announced  in  the  September  number  of  The  Electrical  Experimenter.  And  don't  forget  we  must  have 
thoroly  "practical"  ideas.    Address  the  Editor,  Radio  Problem  Contest. 


A  GROUP  OF  REPRESENTATIVE  AMERICAN  AMATEUR  RADIO  STATIONS. 

Ma°s°s  !*2— Rldin  S  nfWAr,d6d  *r?  Amateu£  Radl°  Station  of  8— Parker  Wiggin,   Kansas  City,   Kan.     1— William   P.  Aldrich,  Westfield, 
Citv    'ivir,  •  =ad  ?,  s,\at,0S  0f  0rn.?y,  Dunnum-  Hannaford,  N.  D. ;  3— N.  W.  Lockwood,  East  Orange,  N.  J.;  4— Lucas  Tylekens,  Jr.,  Kansas 
H    Cook    Itef^n    N    ve!Tnr'  ^Mwaukee,  W  s. ;  6-Lester  S.   Fawcett,  Independence,  Iowa;  7-Ole  B.  Ritchey,  Lake  City,  Mich.;  9-Lovlll 
U00k'   Mexic°.   N.  Y.;  10— Henry  W.  Hall,   Beeville,  Tex.;   11— Otto   Vandell,   Brooklyn,   N.   Y.;   12— Hubert   F.  Jordan,   Evanston,  111.; 

13 — Palmer  Reist,   Dayton,  O. 


206 


THE  ELECTRICAL  EXPERIMENTER 


July,  1917 


Some  More  Representative  American  Amateur 

Radio  Stations. 


14 — Radio  Station  of  Louis  Falconi,  Fort  Stanton,  N.  Mex.;  15 — Lessesne  R.  Allison,  Statesville,  N.  C;  16 — Frank  O.  Walsh,  Jr.,  Augusta, 
Ga.;  17 — Geo.  Anderson,  Dorchester,  Mass.;  18 — James  B.  Armstrong,  Ithaca,  N.  Y.;  19 — L.  C.  Herndon,  Portsmouth,  Va.;  20 — Allen  B.  Du 
Mont,  Montclair,  N.  J.;  21 — Morris  Pollack,  Chicago,  III.;  22— H.  Muyskins,  Jr.,  Lynden,  Wash.;  23 — Geo.  M.  Bends,  Utica,  N.  Y.;  24 — Earl 
McClure,  Van  Wert,  O.;  25 — Butswick  Brattland,  Ada,  Minn.;  26 — Geo.  E.  Meldrum,  Jr.,  Carrollton,  III.;  27 — Clyde  R.  Battin,  Athens,  Ohio. 


July,  1917 


THE   ELECTRICAL  EXPERIMENTER 


207 


THE  MARVELS  OF  RADIO- 
ACTIVITY. 

(Continued  from  page  171) 

of  the  leaves  being  indicative  of  the  amount 
of  Radium  in  a  certain  amount  of  sample. 

Rutherford  showed  that  the  discharging 
effect  is  due  to  the  production  of  ions 
or  charged  particles  of  the  gas  thru  which 
the  radiations  pass.  In  an  electric  field, 
positive  ions  travel  to  the  negative  electrode 
and  vice  versa ;  thus  causing  the  discharge 
of  an  electrified  body.  If  a  sufficiently 
strong  field  is  used,  the  ions  are  all  swept 
to  the  electrodes  without  appreciable  loss. 
The  rate  of  discharge  then  reaches  a  maxi- 
mum, which  is  not  altered  by  an  increased 
voltage,  this  maximum  current  being  called 
the  saturation  current.  The  ions  produced 
are  in  every  way  identical  with  those  pro- 
duced by  X-rays.  This  phenomenon  of 
ionization  is  the  basis  for  the  conductivity 
of  gases  caused  by  radioactive  substances. 

Radium 

Radium  has  been  definitely  determined 
as  an  element,  atomic  weight  226.2  (Mme. 
Curie).  It  imparts  a  brilliant  red  color 
to  a  flame  and  red  predominates  in  its 
flame  spectrum.  The  production  of  Radium 
is  in  this  country  largely  from  the  ore 
carnotite,  an  Uranium  oxid,  found  in 
Colorado  and  Utah.  The  Radium  is  ex- 
tracted by  chemical  means  from  the  ore  to- 
gether with  Barium,  from  which  it  is  sepa- 
rated by  fractional  crystallization.  The 
bromid  salt  of  Radium  is  slightly  less  sol- 
uble than  that  of  Barium,  so  on  cooling 
a  solution,  crystals  richer  in  Radium  than 
in  Barium  separate  out  first.  After  six  or 
eight  successive  operations,  pure  crystals 
of  Radium  bromid  are  obtained,  which  are 
then  ready  for  the  market. 

The  prominence  attained  by  Radium  is 
due  more  to  its  ease  of  production  and  the 
amount  of  easily  secured  ore  than  to  any 
exceptional  properties  it  possesses  over 
many  of  the  other  radioactive  elements. 

Besides  the  radiations  given  off  by  Ra- 
dium, there  is  produced  in  addition  a  gas, 
known  as  "emanation."  This  gas  is  about 
a  hundred  thousand  times  as  active  as 
Radium  itself.  When  introduced  into  a 
glass  tube  it  causes  a  bright  glow.  This 
glow  increases  to  a  brilliant  illumination 
when  substances  which  phosphoresce,  as  zinc 
sulfid,  are  put  into  a  tube  containing 
emanation.     Fig.  2. 

By  means  of  this  emanation  a  finer  esti- 
mation of  amounts  of  Radium  than  by  the 
ordinary  electroscopic  method  can  be  made. 
The  emanation  is  driven  off  by  boiling  and 
conducted  into  a  suitable  electroscope  and 
the  rate  of  collapsing  of  the  leaves  noted 
as  compared  to  a  standard.  Quantities 
of  radium  as  small  as  .000,000,000,001  gram 
can  be  detected  and  determined.  This 
emanation  method  is  used  to  determine  the 
amount  of  Radium  in  rocks  and  minerals. 

Another  method  for  quantitative  measure- 
ments of  small  amounts  of  Radium,  when 
not  less  than  1/100  of  a  milligram  is  pres- 
ent, is  to  place  the  tube  containing  the 
Radium  some  distance  from  a  lead  screen 
and  measure  the  rate  of  discharge  of  an 
electroscope,  as  compared  with  the  rate 
caused  by  a  standard  amount  of  radium 
similarly  placed.  The  material  being  in- 
vestigated must  be  at  least  a  month  old, 
in  order  that  the  emanation  be  in  equil- 
ibrium with  the  Radium  (due  to  decay 
and  recovery,  as  explained  later).  This 
method  is  simple  and  direct,  as  the  tube 
need  not  be  opened  nor  the  material 
weighed. 

The  radioactive  substance,  Actinium,  also 
gives  off  an  emanation,  whose  activity  dies 
m  a  few  seconds.    Polonium  likewise  un- 


NIKOLA   TESLA    RECEIVES  THE 
"EDISON  MEDAL." 

Nikola  Tesla,  the  famous  electrical 
wizard,  who  was  awarded  the  seventh  Edi- 
son medal  on  December  13,  1916,  "for 
meritorious  achievements  in  his  early  orig- 
inal work  in  polyphase  and  high-frequency 
electric  currents,"  received  the  medal  at  a 
presentation  made  at  the  annual  meeting 
of  the  American  Institute  of  Electrical  En- 
gineers, on  May  18. 

The  Edison  Medal  was  established  upon 
the  initiative  of  a  group  of  friends  and 
associates  of  Thomas  A.  Edison,  for  the 
purpose  of  recounting  and  celebrating  the 
achievements  of  a  quarter  of  a  century  in 
the  art  of  electric  lighting,  with  which  the 
name  of  Edison  is  imperishably  identified. 
It  was  decided  that  the  most  effective 
means  of  accomplishing  this  object  would 
be  by  the  establishment  of  a  gold  medal, 
which  should,  during  the  centuries  to  come, 
serve  as  an  honorable  incentive  to  scien- 
tists, engineers  and  artisans  to  maintain 
by  their  works  a  high  standard  of  accom- 
plishment. 

The  Edison  Medal  was,  therefore,  es- 
tablished and  endowed  with  a  trust  fund, 
under  an  indenture  dated  February  11, 
1904,  whereby  the  American  Institute  of 
Electrical  Engineers  agreed  to  award  the 
medal  annually.  It',  is  awarded  each  year 
by  a  committee  consisting  of  24  members 


dergoes  a  series  of  changes,  there  being 
considerable  evidence  that  the  final  product 
is  lead.  Polonium  is  much  more  active 
than  Radium,  but  occurs  in  smaller  quan- 
tities. Marckwald  obtained  three  milligrams 
from  fifteen  tons  of  pitchblende  residue. 
The  amount  of  Polonium  in  a  Radium 
mineral  is  1/5000  of  the  amount  of  the 
Radium. 

Another  body,  known  as  "Ionium,"  has 
been  recently  separated  with  similar  radio- 
active properties.  Ionium  compounds  are 
several  thousand  times  as  active  as  those 
of  Uranium.  The  especial  interest  in 
Ionium  is  that  its  decomposition  product 
is  Radium,  altho  its  period  of  transforma- 
tion is  much  longer  than  that  of  Radium. 

It  has  been  found  that  Uranium,  Ionium, 
Radium,  Actinium,  Thorium — all  break 
down,  some  giving  off  emanation,  into  new 
substances  which  in  turn  break  down  again 
into  others,  and  so  on  thru  the  series. 
This  phenomenon  is  nothing  more  or  less 
than  a  spontaneous  commutation  of  mat- 
ter. 

Perhaps  the  ancient  Alchemists'  ideas 
were  not  entirely  wrong! 

(To  Be  Continued) 


ELECTRIC  RESISTANCE  OF 
SELENIUM  CELLS. 

According  to  Professor  H.  Greinacher 
of  Zurich,  selenium  cells  of  the  original 
Shalford  Bidwell  type,  which  he  studied 
together  with  Mr.  C.  W.  Miller,  behave 
with  respect  to  alternating  currents  as  they 
behave  when  exposed  to  light,  and  show 
polarity  when  traversed  by  continuous  cur- 
rents. Communicating  his  observations  to 
the  German  Physical  Society,  Greinacher 
stated  that  the  resistance  of  the  selenium 
cell  rose  when  direct  current  flowed  in  the 
dark,  that  this  increase  in  resistance  was 
different  for  positive  and  for  negative  cur- 
rents and  increased  with  the  time,  and  that 
selenium  cells  acted  in  a  certain  sense  like 
current  rectifiers.  These  statements  are 
questioned  by  Dr.  Robert  Furstenau  of 
Berlin,  who,  in  experimenting  with  hun- 
dreds of  selenium  cells  with  similar  bridge 
arrangements  as  Greinacher,  had  never  no- 
ticed any  of  these  effects.    Furstenau  sug- 


of  the  Institute  to  a  resident  of  the  United 
States  of  America  and  its  dependencies, 
or  of  the  Dominion  of  Canada,  "for  meri- 
torious achievement  in  electrical  science  or 
electrical  engineering  or  the  electrical  arts." 

B.  A.  Behrend  said  :— 

"By  an  extraordinary  coincidence,  it  is 
exactly  twenty-nine  years  ago,  to  the  very 
day  and  hour,  that  there  stood  before  this 
Institute  Nikola  Tesla,  and  he  read  a  de- 
scription of  his  great  discovery  of  the  gen- 
eration and  utilization  of  polyphase  alter- 
nating currents.  He  left  nothing  to  be 
done  for  those  .  who  followed  him.  His 
paper  contained  the  skeleton  even  of  the 
mathematical  theory. 

"Three  years  later,  in  1891,  there  was 
given  the  first  great  demonstration,  by 
Swiss  engineers,  of  the  transmission  of 
power  at  30,000  volts  from  Lauffen  to 
Frankfort  by  means  of  Mr.  Tesla's  sys- 
tem. A  few  years  later  this  was  followed 
by  the  development  of  the  Cataract  Con- 
struction Company,  under  the  presidency  of 
our  member,  Edward  D.  Adams,  and  with 
the  aid  of  the  engineers  of  the  Westing- 
house  Company.  It  is  interesting  to  re- 
call here  to-night  that  in  Lord  Kelvin's 
report  to  Mr.  Adams,  Lord  Kelvin  recom- 
mended the  use  of  direct  current  for  the 


Nikola  Tesla,  Prince  of  Electrical  Inventors, 
Who   Was   Recently   Awarded   the  "Edison 
Medal." 


development  of  power  at  Niagara  Falls 
and  for  its  transmission  to  Buffalo. 

"The  basis  for  the  theory  of  the  oper- 
ating characteristics  of  Mr.  Tesla's  rotat- 
ing-field  induction  motor,  so  necessary  to 
its  practical  development,  was  laid  by  the 
brilliant  French  savant  Prof.  Andre  Blon- 
del,  and  by  Professor  Kapp  of  Birming- 
ham. It  fell  to  my  lot  to  complete  their 
work  and  to  co-ordinate — by  means  of  the 
simple  'circle  diagram' — the  somewhat  mys- 
terious and  complex  experimental  phenom- 
ena. As  this  was  done  twenty-one  years 
ago,  it  is  particularly  pleasing  to  me,  upon 
the  coming  of  age  of  this  now  universally 
accepted  theory — tried  out  by  application 
to  several  million  horse-power  of  machines 
operating  in  our  great  industries — to  pay 
my  tribute  to  the  inventor  of  the  motor 
and  the  system  which  have  made  possible 
•the  electric  transmission  of  energy.  His 
name  marks  an  epoch  in  the  advance  of 
electrical  science.  From  that  work  has 
sprung  a  revolution  in  the  electrical  art." 


gests  that  Greinacher's  cells  had  been  of 
pecidiar  kind.  That  selenium  cells  are  very 
sensitive  to  moisture,  and  that  the  elec- 
trode material  may  have  peculiar  puzzling 
effects,  is  fairly  well  understood,  and  these 
features  may  explain  some  of  the  contro- 
versial statements  made  from  time  to  time. 


208 


THE  ELECTRICAL  EXPERIMENTER 


July,  1917 


PATENTS 


Electric  Light  for  Razors 

(No.  1,223,305;  issued  to  Katherine 
E.  Allport.) 
At  last  an  inventor  has  come  to 
the  rescue  of  the  long-suffering 
bath-room  barber  and  here  provides 
a    simple   electric    light  attachment 


so  that  one  may  see  at  all  times 
on  any  part  of  the  face,  which  is 
usually  difficult  with  the  ordinary 
source  of  illumination,  due  to 
shadows.  She  also  provides  a  neat 
combined  razor  and  battery  cabinet, 
the  lower  part  containing  a  suitable 
dry  battery,  with  a  flexible  cord  to 
connect  the  miniature  lamp  with  the 
battery.  A  new  battery  may  be 
quickly  placed  in  the  cabinet  by 
means  of  a  sliding  bottom.  The 
device  would  seem  of  extreme  value 
to  all  military  and  traveling  men. 

The  Electrolytic  Rectifier 

(No.  1,223,114;  issued  to  Charles  C. 
Ruprecht.) 
An  improvement  in  the  design  of 
electrolytic  rectifiers  which  con- 
duces to  the  thoro  circulation  of 
the   electrolyte  solution,  as  the  ar- 


rows in  diagram  illustrate.  The 
metal  electrodes  7  and  8  are  placed 
in  a  small  chamber  which  com- 
municates with  the  main  circulating 
chamber  thru  two  ports,  the  solu- 
tion continually  rising,  due  to  heat- 
ing, and  passing  thru  the  salts  de- 
posited in  the  lower  part  of  the 
pocket  formed  by  diagonal  grid  as 
indicated.  The  inventor  claims 
that  the  solution  will  thus  be  kept 
saturated  at  all  times  and  that  heat- 
ing is  reduced  to  a  minimum,  with 
increased   efficiency  in  consequence. 

Night-Sight  for  Firearms 

(No.  1,225,592;  issued  to  Britannio 
Solaro.) 

A  clever  invention  of  particular 
value  at  this  time  and  involving  the 
use  of  special  back  and  fore-sights 
for  rifles  or  other  firearms,  each 
sight  being  provided  with  chambers 


or  cavities  enclosed  by  a  lens,  and 
adapted  to  contain  a  salt  of  radium 
which  will  emit  rays  of  light,  these 
being  concentrated  as  a  spot  of 
light  by  the  lens  in  each  case. 
When  the  back-sight  and  fore-sight 
are  applied  to  a  rifle,  as  shown,  it 
becomes  evident  that  the  ordinary 
sights  of  the  rifle  will  not  be  ob- 
structed. 


Galvanic  Cell 

(No.  1,221,062;  jssued  to  Morduch 
L.  Kaplan. ) 
New  design  of  miniature  dry  cell 
as  used  particularly  for  flash-lights. 
Use  is  made  in  this  cell  of  a  higher 
oxid  of  manganese,  which  appar- 
ently consists  of  manganese  in  two 
or  more  stages  of  oxidation,  and  in 
a  peculiar  form  whereby  extremely 
satisfactory  depolarizing  action  is 
secured,  and  whereby  it  becomes 
possible  to  concentrate  and  compact 
finely-divided  grafite  or  other  suit- 
able form  of  conducting  carbon  with 
such  a  quantity  of  the  depolarizing 


compound  that  long  life  of  the  cell 
is  assured.  The  inventor  has  found 
that  a  lower  oxid  is  desirable  in 
combination  with  the  higher  oxid,  to 
assure  a  novel  and  pronounced  de- 
polarizing action.  He  claims  by 
this  means  a  certain  measure  of 
transference  of  oxygen  from  the 
interior  to  the  exterior  of  the  cell, 
so  that  depolarizing  efficiency  does 
not  depend  merely  on  surface  ex- 
posure, but  also  on  the  gross  amount 
of   the    manganese  compound. 


Electric  Interrupter 

(No.    1,224,570;    issued    to  Stuart 
Sandreuter.) 
An    electric    interrupter  intended 


for  low  frequencies  and  comprising 
an  insulating  disc  which  carries  a 
ring  of  conductive  material  provided 
with  a  plurality  of  radial  exten- 
sions between  which  are  mounted 
insulating  strips  or  segments.  The 
disc  shaft  may  be  driven  by  a  motor 
or  other  device  in  order  to  rapidlv 
rotate  the  same.  Contact  with  the 
rapidly  rotating  segmented  metal 
ring  is  effected  thru  a  spring  actu- 
ated rolling  wheel.  Connection  is 
made  with  the  segmented  perifery 
of  the  rotating  disc  by  means  of  a 
suitably  proportioned  metal  wheel 
14.  This  is  pivoted  in  a  sliding 
metal  block  11,  constantly  'pushed 
forward  by  a  spiral  spring  15,  and 


connected  with  binding  post  10  by 
flexible  conductor  17. 


Alternating  Current  Rectifier 

(No.    1,221,981;    issued   to  Thomas 
A.  Edison.) 
A    simplified    form    of  vibrating 
rectifier    for   charging    storage  bat- 
teries, etc.    It  involves  a  permanent 


steel  polarizing  magnet,  a  set  of 
vibrating  reeds  and  an  actuating 
magnet  coil.  The  contacts  on  the 
vibrators  and  fixt  electrodes  are  of 
special  carbon  to  cut  down  arcing 
and  sticking  of  contacts.  By  con- 
necting the  rectifying  contacts  in 
parallel  a  large  current  capacity  is 
obtained;  in  series  a  relatively  high 
potential  current  can  be  handled. 
The  amplitude  of  movement  of  the 
vibratory  contacts  is  small — about 
10    thousandths   of    an  inch. 


Ionized-Chamber  Device 

(No.  1,222,916;  issued  to  Clifford 
Dudley  Babcock.) 
A  clever  arrangement  for  ionized- 
chamber  detectors  or  amplifiers  of 
the  de  Forest  type,  and  here  shown 
in  a  de  Forest  radio  receiving  cir- 
cuit. The  inventor  simplifies  the 
construction  and  gains  the  advan- 
tage of  having  a  finely  adjustable 
variable  condenser  incorporated  in 
the  device  itself,  by  means  of  two 


metal  sleeves  placed  inside  and  out- 
side of  the  tubular  glass  bulb.  The 
inner  sleeve  supports  the  usual  grid 
and     is     charged     thru     the  glass 


inu  is  cnargeu  inru  tn<_ 
dielectric  from  the  outer  sliding 
metal  sleeve,  connected  in  the  circuit 
as  shown. 


Undamped  Wave  Receiver 

(No.  1,224,343;  issued  to  James  O. 
Watkins.) 
The  "tikker"  apparatus  comprises 
a  suitable  base  and  upright  members 
of  small  size,  and  which  serve  to 
support  adjustably  a  metal  wire  or 
string.  The  tension  of  this  string 
is  adjustable  by  raising  or  lowering 


a  pointed  tension  block  A,  by  means 
of  thumb  screw  B.  The  string  is 
vibrated  at  radio  frequency  by 
means  of  a  smooth-edged  disc 
mounted  on  the  shaft  of  a  motor. 


Radio-Telegraph  Receptor 

(No.  1,224,499;  issued  to  Greenleaf 
Whittier  Pickard.) 
An  improved  method  of  receiving 
radio-telegraphic  or  telephonic  sig- 
nals wherein  (Fig.  1)  the  secondary 
coil  C  has  only  one  side  connected 
to  the  receiving  apparatus  D-T, 
which  may  be  grounded.  Fig.  2 
shows  a  like  arrangement  except 
that  the  coupling  between  aerial  A 
and  primary  B  is  made  inductively. 
Fig.  3  is  similar  to  Fig.  1,  except 
that  two  primaries  B  and  Bl  are 
used.  T  may  be  a  telephone  re- 
ceiver, and  D  a  crystal  rectifying 
detector.  Coil  B  is  of  sufficient 
length  to  cause  its  natural  period  to 
be  equal  to  the  shortest  desired 
wave  length.  The  secondary  C,  is 
adapted  to  slide  in  the  primary  B, 

c 


A  I 


,  ^fulfil, 

and  consists  of  but  a  few  turns  of 
coarse  wire  having  a  natural  period 
much  smaller  than  the  shortest  de- 
sired wave  length. 


Aerial  Torpedo  Steering  Device 

(No.  1,222,630;  issued  to  Lemuel 
John  Husted.) 
A  unique  idea  involving  the  use 
of  "magnetic  attraction"  to  actuate 
a  special  rudder  control  switch  so 
as  to  cause  an  aerial  torpedo  or 
similar  projectile  to  unfailingly 
reach  its  target  when  the  latter  is 
composed  of  a  steel  or  iron  shell 
structure.     The   lower  part  of  the 


torpedo  contains  a  charge  of  explo- 
sives to  be  detonated  by  an  electric 
fuse  10-11,  operated  by  switch  15, 
when  the  missile  strikes  its  target. 

The  inventor  provides  an  "attrac- 
tion" electro-magnet  9,  suspended  to 
swing  in  any  direction. 


COPIES  OF  ANY  OF  THE  ABOVE  PATENTS  SUPPLIED  AT  10c  EACH 


July,  1917 


THE   ELECTRICAL  EXPERIMENTER 


209 


Phoney  Patent  Offizz 


Under  this  heading  are  publisht  electrical  or  mechanical  ideas  which 
our  clever  inventors,  for  reasons  best  known  to  themselves,  have  as  yet 
not  patented.  We  furthermore  call  attention  to  our  celebrated  Phoney 
Patent  Offizz  for  the  relief  of  all  suffering  daffy  inventors  in  this  country 
as  well  as  for  the  entire  universe. 

We  are  revolutionizing  the  Patent  business  and  OFFER  YOU  THREE 
DOLLARS!  $3.00  FOR  THE  BEST  PATENT.  If  you  take  your  Phoney 
Patent  to  Washington,  they  charge  you  $20.00  for  the  initial  fee  and  then 


you  haven't  a  smell  of  the  Patent  yet.  After  they  have  allowed  the  Pat- 
ent, you  must  pay  another  $20.00  as  a  final  fee.  That's  $40.00  !  !  WE 
PAY  YOU  $3.00  and  grant  you  a  Phoney  Patent  in  the  bargain,  so  you 
save  $43.00  !  !  When  sending  in  your  Phoney  Patent  application, 
be  sure  that  it  is  as  daffy  as  a  lovesick  bat.  The  daffier,  the  better. 
Simple  sketches  and  a  short  description  will  help  our  staff  of  Phoney 
Patent  examiners  to  issue  a  Phoney  Patent  on  your  invention  in  a 
jiffy. 


No 


(M.  I.  L.  K.°\ 
Ha0  / 


Lapup  Cowjuce  of  Milkshake,  N.  D. 

CUDOMOTOR 


Patent  Appraised 


To  Whome  It  May  Constcrn; 

Be  it  appraised  to  all  cows,  calves,  dairy- 
men, dairymaids,  dairyouths,  dairywomens, 
and  all  others  interested  in  the  lacto  indus- 
try, that  I,  Lapup  Cowjuce  of  the  City  of 
Milkshake,  in  the  State  of  Nervous  Depres- 
sion, have  at  the  risk  of  my  decaying  sanity, 
invented  and  designed  a  world-upheaving 
device,  whereby  it-  is  made  possible  at  last 
for  cows  to  milk  themselves,  automatically 
without  cost  or  expense. 


away  (patent  applied  for).  To  her  jaws 
are  now  attached  jaw  clamps  A.  These  in 
turn  are  attached  to  a  scissor-mechanism  B, 
pivoted  on  silk  ball-bearings  as  shown.  It 
becomes  apparent  that  as  the  cow  chews,  the 
scissor  mechanism  is  given  a  reciprocating 
movement.  This  motion  is  transmitted  thru 
lateral  zinc  rods  C,  connected  in  turn  to 
brass  cranks  D.  By  means  of  soft  rubber 
pulley  E,  the  wooden  belt  F  now  transmits 
the  resulting  energy  to  the  selenium  pulley 


Galena  is  used  on  the  stop-cock  because  it 
is  very  sensitive.  The  oscillating  air  next 
flirts  into  the  quartz  pulsator  U,  from  which 
it  escapes  to  liberty.  This  creates  a  pulsat- 
ing vacuum  in  the  scanatory  Bakelite  milk 
can  R.  But  as  the  latter  is  connected  by 
means  of  a  flexible  hard-rubber  tube  T,  to 
the  cow's  teats,  by  means  of  teat-cups  (not 
tea-cups)  it  follows  that  the  milk  is  drawn 
rapidly  into  the  can  R. 
1  /  hat  1  claim  is.; 


NO-MILK  SWITCH 

tffi. 


GRASS  FOR  CUD  N0.2  ^> 
PAT. APPLIED  FOR 


"  .  .  .1,  Lapup  Cowjuce  of  the  City  of  Milkshake,  N.  D.,  Have  at  the  Risk  of  My  Decaying  Sanity,  Invented  and  Designed  a  World  -  Upheav- 
ing Device,  Whereby  It  Is  Made  Possible  At  Last  for  Cows  to  Milk  Themselves  Automatically  By  the  Surplus  'Cow-Power'  Developed  By 

Their  Constant  Cud-Chewing." 


As  is  universally  known  among  cows  and 
dairypeople,  cows  continually  "chew  their 
cud."  Here  we  have  a  constant  form  of 
energy,  which  has  been  calculated  to  repre- 
sent about  9^4  cow-power  per  day.  It  has 
also  been  calculated  that  the  cow  to  chew 
the  cud  efficiently  only  requires  5-)4  cow- 
power.  This  leaves  a  net  wastage  of  4  CP. 
per  day.  This  totally  wasted  energy  I  have 
now  at  last  harnest,  in  as  simple  as  it  is 
efficient  manner.  Not  only  do  I  use  this 
energy  to  milk  the  cow  itself,  but  I  use  it 
also  to  light  the  house,  run  the  butterchurn- 
er  as  well  as  the  buttermilker. 

_  First  the  cow  is  secured  properly  to  a 
simple  mechanism  to  keep  her  from  backing 


of  Dynamo  G.  This  latter  on  account  of  the 
oscillatory  moving  jaws  of  the  cow,  gen- 
erates an  oscillating  alternating  current, 
which  then  charges  the  alternating  current 
storage  batten-  H.  This  resulting  current 
oscillates  thru  the  Tungsten  switchboard  I, 
and  thence  thru  the  connecting  platinum 
cables  J.  The  current  then  drives  the  bash- 
ful motor  K  which  now  operates  the  anaemic 
hot-air  compressor  L.  The  resulting  com- 
prest  and  perfumed  air  is  then  stored  free 
of  charge  in  the  leather  tank  M.  Hot  wire 
ammeter  N  is  used  to  observe  too  high  a 
temperature.  The  air  is  now  conveyed  thru 
glass  pipe  O,  thru  Galena  stop-cock  P, 
thence  thru  flexible  cast  iron  supply  pipe  Q. 


1st — An  automatic  cow-milk  dispenser, 
dispensing  with  all  milkmaids. 

2nd — A  cow-milker  operated  by  the  cow's 
own  cud-chewing. 

3rd — A  motor  attachable  on  all  rumina- 
tors  and  other  rummies. 

In  memoriam  henceforth  and  hencewith  I 
have  therefore  caused  and  bv  these  presents 
do  hereby  depose  upon  this  legal  instru- 
ment my  south-western  uppermost  back- 
hoof,  this  3rd  clay  of  our  Grace,  in  the  149th 
year  of  the  French  Revolution. 
fitnesses;  Lapup  Cowjuce, 

A.  Heluvaguy,  By  his  attorney; 

A.  W.  Drvup,  Leonard  Sarver, 

S.  O.  Mecrust.  Enid,  Okla 


210 


THE  ELECTRICAL  EXPERIMENTER 


July,  1917 


Question  Box 


This  department  is  for  the  sole  benefit  of  all  electrical  experimenters.  Questions  will  be  answered  here  for  the  benefit  of  all,  but  only 
matter  of  sufficient  interest  will  be  publish!    Rules  under  which  questions  will  be  answered: 

1.  Only  three  questions  can  be  submitted  to  be  answered. 

2.  Only  one  side  of  sheet  to  be  written  on;  matter  must  be  typewritten  or  else  written  in  ink;  no  penciled  matter  considered. 

3.  Sketches,  diagrams,  etc.,  must  be  on  separate  sheets.    Questions  addrest  to  this  department  cannot  be  answered  by  mail  free  of  charge. 

4.  If  a  quick  answer  is  desired  by  mail,  a  nominal  charge  of  25  cents  is  made  for  each  question.  If  the  question  entail  considerable  re- 
search work  or  intricate  calculations  a  special  rate  will  be  charged.  Correspondents  will  be  informed  as  to  the  fee  before  such  questions  are 
answered. 


BUZZER  TELEGRAPH  SYSTEM. 

(801.)  O.  M.  Warren,  Detroit,  Mich., 
asks : 

Q.  1.  Would  it  be  possible  to  use  the 
following  scheme  to  telegraph  a  distance 
of  a  block  or  two? 


Rece/'wng 
telephone^, 


a  80i 


An  Effective  "Buzzer"  Telegraph  System 
Which  Employs  Two  "Ground"  Plates  at 
Each  Station,  Each  Plate  Buried  at  a  Differ- 
ent Level.  A  Radio  Detector,  Fixt  Condenser 
and  Telephone  Receiver  Are  Used  at  the  Re- 
ceiving Station. 

A.  1.  Yes.  You  will  have  no  trouble  in 
transmitting  considerably  more  than  the 
distance  you  mention. 

Q.  2.  If  possible  would  a  tuning  coil  or 
loose  coupler  connected  in  the  receiving 
circuit  improve  it? 

A.  2.  A  tuning  coil  or  loose  coupler 
should  not  be  used  with  this  system,  as 
it  is  impossible  to  tune  any  distant  signal 
with  this  ground  telegraph  system,  speak- 
ing generally.   

ADHESION  PHENOMENON. 

(802.)  Betram  Wertheim,  N.  Y.,  writes 
us  : 

Q.  1.  Whenever,  after  typing  carbon 
copies,  I  find  that  a  strange  phenomenon 
occurs.  The  papers,  including  the  carbons, 
are  charged  with  static  electricity  and  they 
all  adhere  to  each  other.  The  most  pecu- 
liar thing  about  this  phenomenon  is  that 
all  the  papers  seem  neither  to  be  charged 
negatively  or  positively,  but  neutrally.  No 
matter  how  I  change  their  positions  to 
each  other,  they  always  attract.  I  there- 
fore come  to  the  conclusion  that  they  must 
be  charged  neutrally,  or  by  some  new  form 
of   static  electricity. 

A.  1.  The  peculiar  phenomenon  which 
you  have  observed  with  the  paper  sheets 
is  due  directly  to  the  adhesion  properties  of 
air  when  it  comes  in  contact  with  paper 
and  when  the  papers  are  separated,  they 
stick  to  each  other.  A  similar  experiment 
can  be  demonstrated  by  placing  a  sheet  of 
paper  on  a  flat  table  and  quickly  lifting 
it  up ;  you  will  observe  that  the  paper  will 
tend  to  stick  to  the  table.  This  is  due  to 
the  adhesion  properties  of  air ;  also  a  par- 
tial vacuum  is  usually  created.  There  is 
nothing  electric  about  it. 


OXYBENZYLMETHYLENGLY- 
COL  ANHYDRIDE. 

(803.)  Harold   Betts,   Sacramento,  Cal., 

wishes  to  know : 


Q.  1.  What  is  the  chemical  symbol  for 
"Oxybenzylmethylenglvcolanhy  dride"  (  Ba- 
kelite)? 

A.  1.  At  the  present  time  there  is  no 
chemical  symbol  to  the  Bakelite  as  the 
chemical  decomposition  of  phenol,  which 
is  the  ingredient  used  in  the  making  of 
this  compound  is  still  a  puzzle  to  the  mod- 
ern chemist.  It  is  one  of  the  most  diffi- 
cult problems  of  the  chemist  to  obtain  the 


M       ODD  PHOTOS  WANTED  AT  M 
$1.00  EACH!!! 

g  Now  is  the  time  to  make  your  g 
g  Kodak  pay  for  itself  in  a  real  praeti-  g 
=1  cal  way.  We  are  after  interesting  g 
g  photographs  of  out-of-the-ordinary  = 
jl  electrical,  radio  and  scientific  sub-  g 
g  jects  and  are  willing  to  pay  $1.00  cash  g 
m  for  every  one  we .  can  use.  Please  g 
g  bear  in  mind  that  for  half-tone  re-  g 
|H  production  in  a  magasine ,  a  photo-  g 
g  graph  should  be  particularly  sharp  g 
g  and  clear.  Of  course,  if  a  subject  g 
U  happens  to  interest  us  particularly  g 
g  well,  we  can  have  the  photo  retouched.  g 
m  For  the  general  run  of  subjects,  how-  g 
H  ever,  it  does  not  pay  to  go  to  such  g 
i§  expense.  Therefore,  please  take  pains  g 
111  to  properly  focus  and  expose  your  g 
g  pictures.  It  often  happens  that  a  g 
g  really  mediocre  subject  well  photo-  ]| 
HI  graphed  wins  approval  over  an  ex-  g 
=  cellent  subject  poorly  photographed,  g 
WS  And  don't  send  us  plate  or  film  "nega-  g 
g  tives:"  send  unmounted  or  mounted  g 
g"  "prints,"  preferably  a  light  and  a  dark  B 
§§§  one.  g 
H  As  to  what  to  photograph:  Well  §1 
H§  that's  hard  for  us  to  say.  We  leave  §§j 
H  that  up  to  you,  and  every  reader  now  g 
=  has  the  opportunity  to  become  a  re-  g 
U  porter  of  the  latest  things  in  the  realm  g 
g  of  Electricity,  Radio  and  Science.  g 
§§§  But,  please  remember — it's  the  "odd,  |I 
=J  novel  or  practical  stunts"  that  we  are  g 
g  interested  in.  Every  photo  submitted  §§§ 
§§§  should  be  accompanied  by  a  brief  dc-  g 
g  scription  of  100  to  150  words.  Give  g 
Hi  the  "facts" — don't  worry  about  the  3 
HHI  style.  We'll  attend  to  that.  Enclose  §f§ 
§§§  stamps  if  photos  are  to  be  returned  g 
U  and  place  a  piece  of  cardboard  in  the  g 
H  envelope  with  them  to  prevent  mutila-  g 
g  tion.  Look  around  your  town  and  g 
g  see  what  you  can  find  that's  interest-  ||| 
HI  ing.  g 
-  To  give  some  idea  of  the  freak  g 
j§  photos  we  like — refer  to  page  188.  g 
§§§  Address  photos  to — Editor  "Odd  ffj 
§§§  Photos,"  Electrical  Experimenter,  g 
g  233  Fulton  Street,  New  York  City.  g 

■  y     i  '  i '!  ^  :  -  .     :  ■  1  : .1 

symbol  of  an  organic  compound,  and 
Bakelite  is  one  of  these. 

Q.  2.  Which  is  the  best,  an  aerial  of 
two  wires  fifty  feet  long,  or  an  aerial  of 
one  wire  one  hundred  feet  long?  Why? 

A.  2.  As  to  whether  the  antenna  is  to 
be  used  for  receiving  or  transmitting,  the 
two  wires  50  feet  long  are  better  for  the 
latter  purpose,  as  the  antenna  must  have 


as  much  capacity  as  possible  in  order  to 
obtain  the  maximum  efficiency  therefrom, 
and  when  combining  the  two  conductors, 
the  capacity  is  increased.  A  single  wire 
100  feet  long  is  desirable  for  receiving 
purposes,  as  the  capacity  of  such  antenna 
is  uniformly  distributed  and  at  the  same 
time  the  inductance  is  increased,  which 
permits  finer'  tuning  of  received  signals. 

Q.  3.  Is  it  possible  to  make  an  electro- 
lytic interrupter  for  a  spark  coil  operating 
on  110  volts  A.  C,  and  if  so,  how? 

A.  3.  Yes.  An  electrolytic  interrupter 
for  this  purpose  can  be  made  by  placing 
a  lead  electrode  in  a  container  and  adding 
a  solution  composed  of  one  part  of  sul- 
furic acid  and  nine  parts  of  water.  A 
second  electrode,  made  of  small  diameter 
iron  wire  is  placed  perpendicularly  to  the 
first  electrode,  as  shown,  taking  care  that 
they  do  not  touch  each  other.  It  is  pre- 
ferable to  enclose  the  iron  wire  or  electrode 
of  smaller  surface  within  a  porcelain  tube 
having  a  small  orifice  at  the  lower  end, 
which  will  just  pass  the  wire.  With  the 
iron  wire  relatively  very  small  as  com- 
pared to  the  surface  of  the  lead  electrode, 
and  with  the  applied  potential  and  current 
critically  adjusted,  as  well  as  the  induct- 
ance and  capacity  of  the  circuit  properly 
balanced,  an  interruption  action  can  be 
effected. 

The  interrupter  is  then  connected  in  the 
usual  way  and  the  wiring  diagram  here- 
with gives  the  proper  connections.  The 
choke  coil  which  is  connected  in  the  pri- 
mary circuit  should  consist  of  an  iron  wire 
core  one  inch  in  diameter  and  12  inches 
long.  Two  layers  of  No.  14  D.C.C.-mag- 
net  wire  are  wound  on  it.  This  coil  should 
invariably  be  used,  as  considerable  trouble 
is  encountered  in  running  electrolytic  in- 
terrupters on  alternating  current. 


Elect. 


I/O  V  AC. 


a  80s 


ClJokecoil 


Simple   Electrolytic    Interrupter  for   Use  on 
Alternating    Current    Circuits    with  Spark 
Coils  or  Open  Core  Transformers. 


AUDION  CIRCUIT  QUERY. 

(804.)  Oscar  F.  Miller,  Milwaukee,  Wis., 
says : 

Q.  1.  I  have  a  receiving  apparatus  com- 
posed of  the  following: — Audion  detector, 
4,500  meter  loose  coupler,  6  volt — 60  amp. 
hour  storage  battery,  Brandes'  'phones,  an 
aerial  150  ft.  long,  4  wires,  which  gave 
very  poor  results.  The  Audion  (de  For- 
est tubular  type)  has  been  tested  and  is 
O.K.  I  am  sending  a  diagram  of  my  set. 
Kindly  advise  me  what  you  think  my  trou- 
ble is. 

A.  1.  The  trouble  is  with  your  wiring 


July,  1917 

diagram,  and  the  only  way  to  remedy  it 
is  to  connect  the  filament  terminal  with 
one  leg  of  the  secondary  of  the  coupler, 
and  disconnecting  the  '"B"  battery  terminal 
with  the  leg  of  the  secondary,  as  you  have 
it  at  present. 


THE  ELECTRICAL  EXPERIMENTER 


21  1 


BOOKS. 

(805.)  H.  H.  Bales,  Halifax,  N.  R, 
wants : 

Q.  1.  The  prices  of  the  following  text 
books :  "Alternating  Current  Electricity 
and  Its  Applications  to  Industry'' — By  W. 
H.  Timbie  and  H.  H.  Higbie,  729  pages, 
Second  Course,  1916.  Also  "Practical 
Electricity."  Latest  edition,  published  by 
the  Cleveland  Armature  Works. 

A.  1.  The  price  of  "Alternating  Current 
Electricity  and  Its  Applications  to  In- 
dustry," is  $3.00,  and  "Practical  Electricity" 
is  worth  $2.00.  These  books,  as  well  as 
any  others,  can  be  obtained  thru  our 
"Book  Department,"  by  sending  amounts 

stated.  ■  ■ 

TELEPHONE  MAGNETS. 

(806.)  A  Reader,  Otsego,  Michigan, 
wishes  to  know : 

Q.  1.  How  can  I  magnetize  telephone 
magneto  magnets  ? 

A.  1.  The  magneto  magnets  can  be  re- 
magnetized  by  employing  an  electro-mag- 
net consisting  of  two  poles ;  the  distance 
between  these  poles  should  correspond  to 
the  distance  between  the  magneto  mag- 
net poles.  By  passing  a  current  thru  the 
electro-magnet  and  holding  the  same  against 
the  poles  of  the  steel  magneto  magnet, 
so  as  to  permit  the  magnetism  to  flow  into 
the  poles  of  the  permanent  magnet,  the 
latter  will  be  revitalized.  The  N.  pole  of 
the  electro-magnet  should  be  placed  against 
the  S.  pole  of  the  magneto-magnet. 

Q.  2.  What  is  the  approximate  voltage 
of  my  telephone  magneto  and  also  the 
amperage?  It  is  a  two-bar  double  mag- 
net type. 

A.  2.  It  is  impossible  for  us  to  give  you 
the  voltage  and  amperage  developed  by 
your  magneto,  as  the  required  data  such 
as  speed  of  armature,  number  of  conduc- 
tors on  the  armature  and  the  flux  density 
is  not  given ;  we  are  thus  unable  to  an- 
swer your  query  and  if  you  will  enlighten 
us  on  the  above-mentioned  points,  we  will 
be  pleased  to  help  you  out  in  this  respect. 
Telephone  magnetos  as  a  rule  develop  be- 
tween 200  and  300  volts  A.  C.  The 
amperage  is  about  1/10  to  1/8. 

Q.  3.  My  radio  receiving  set  consists  of 
a  twenty-seven  hundred  meter  tuner, 
single  slide,  and  a  six-hundred  meter  tuner 
used  as  loader.  I  have  a  silicon  detector, 
fixt  condenser  and  1,000  ohm  receiver.  My 
aerial  was  a  "T"  type  and  comprised  a 
single  "Antenium"  wire  with  lead-in  75 
ft.  long.  Ground  of  iron  pipe  driven  into 
hard  clay.  I  never  heard  anything  but 
static ;  can  you  tell  me  what  the  cause  of 
this  is?  I  have  never  heard  a  signal.  If 
it  is  some  minor  trouble  and  if  I  remedied 
it,  could  I  receive  Arlington  and  N.A.R. 
(Key  West),  with  it? 

A.  3.  The  trouble  is  undoubtedly  with 
your  ground,  and  this  can  be  remedied  by 
placing  a  copper  sheet  about  6  feet  square 
in  the  ground.  This  should  be  placed  10, 
or  even  15  feet  deep,  in  the  earth,  cover- 
ing the  same  with  pulverized  charcoal  and 
impregnating  the  total  mass  with  salt  water, 
which  will  improve  the  ground  conductivity 
considerably. 

In  regard  to  the  reception  of  Arling- 
ton time  signals  with  your  present  equip- 
ment, we  are  very  much  in  doubt  as  to 
whether  it  can  be  done,  but  by  the  employ- 
ment of  an  Audion  detector,  a  variable 
condenser  shunted  across  the  secondary  of 
the  inductive  coupler  and  a  pair  of  2,000 
ohm  'phones,  you  should  have  no  trouble 


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THE  ELECTRICAL  EXPERIMENTER 


July,  1917 


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WIRELESS  TELEPHONE  CON- 
NECTION. 

(807.)  Ivan  Bulock,  Fairmont,  Minn., 
writes  : 

Q.  1.  Which  is  the  best  way  to  connect 
an  ordinary  carbon  grain  transmitter  on 
110-voIt,  6  amp.  d.c,  for  wireless  tele- 
phony? 

A.  1.  The  accompanying  wiring  diagram 
shows  the  best  way  of  connecting  such  a 
transmitter. 

Q.  2.  Could  an  ordinary  one-inch  spark 
coil  be  used  as  a  transformer  for  wireless 
telephony? 

A.  2.  No.  The  current  obtained  from  the 
secondary  of  a  one-inch  spark  coil  is  so 
small  that  it  does  not  warrant  its  use. 


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WWW — Mww— L 


Arc  -sSt  p 


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Transm. 


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© 


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WHAT  IS  SYNCHRONISM? 

(809.)  H.  Somerfelt,  Butte,  Mont,  asks: 

Q.  1.  What  is  meant  by  synchronism? 

A.  1.  This  term  may  be  defined  as  the 
simultaneous  occurrence  of  any  two  events. 
Thus  two  alternating  currents  are  said  to 
be  in  synchronism  when  they  have  the  same 
frequency  and  are  in  phase. 

Q.  2.  For  what  service  are  the  25-cycle 
and  60-cycle  currents  adapted? 

A.  2.  The  25-cycle  frequency  is  used  for 
conversion  to  direct  currents,  for  alternat- 
ing current  railways,  and  for  machines  of 
large  size ;  the  60-cycle  frequency  is  used 
for  general  distribution  for  lighting  and 
power. 

Q.  3.  How  must  an  alternator  be  con- 
structed to  generate  two-phase  current  ? 

A.  3.  It  must  have  two  independent 
windings,  and  these  must  be  so  spaced 
out  that  when  the  E.M.F.  generated  in  one 
of  the  two  phases  is  at  a  maximum,  the 
E.M.F.  generated  in  the  other  is  at  zero, 
i.  c.  they  are  90  degrees  apart,  vectorially 

speaking.  

SOLDERING  QUERIES. 

(810.)  Paul  Johnson,  Poughkeepsie, 
N.  Y.,  wants  to  know : 

Q.  1.  What  is  hard  solder? 

A.  1.  An  alloy  composed  of  copper  and 
zinc,   or   copper,   zinc   and   silver.  Hard 
{Continued  on  page  213) 


BACK  TO  THE  DAYS  OF  VOLTA. 

{Continued  from  page  172) 
Volta  was  one  of  the  most  prolific  in- 
ventors of  all  times.  He  invented  a  greater 
amount  of  basic  electric  apparatus  than  any 
other  living  scientist  with  the  exception  of 
Faraday.  In  Fig.  3,  at  the  left  is  shown  a 
clever  apparatus  which  when  energized  by 
static  electricity  produces  imitation  hail. 
Fig.  3  (at  right)  shows  his  apparatus  for 
exploding  a  mixture  of  oxygen  and  hydro- 
gen by  means  of  an  electric  spark. 


LIGHTNING— HOW   TO  PROTECT 
YOURSELF  FROM  IT. 

{Continued  from  page  175) 
are  dry.  But  let  the  hand  be  wet  with 
water  or  with  perspiration,  or  let  the  per- 
son stand  on  damp  floor  or  ground,  then 
enough  current  may  pass  thru  the  heart  to 
paralyze  it,  and  death  will  occur  suddenly. 
Most  fatalities;  from  industrial  currents 
come  from  those  at  500  volts  to  5,000  volts 
pressure.  People  who  have  received  shocks 
from  a  10,000  volt  current  have  lived. 

At  low  voltages  the  alternating  current  is 
three  to  four  times  as  dangerous  as  the 
direct  current,  but  at  high  voltages  the 
direct  current  is  the  more  dangerous.  It 
is  safe  to  pass  a  current  at  several  hundred 
thousand  volts  pressure  thru  the  body  if 
there  are  over  10,000  alternations  per  sec- 
ond. Three-tenths  of  an  ampere  causes 
death  at  low  rate  of  alternations  but  three 
amperes  can  safely  be  taken  if  the  alterna- 
tions are  half  a  million  per  second.  With 
wet  hands  and  feet  the  resistance  of  the 
human  body  may  be  from  1,000  to  1,500 
ohms.  This  is  not  much  of  a  resistance 
for  the  lightning  at  its  greatest  pressure 
to  overcome.  A  person  standing  isolated 
on  moist  soil  makes  an  attractive  target  for 
the  lightning. 

There  is  a  superstition  that  lightning 
figures,  found  on  the  skin  of  a  person 
struck  by  lightning,  are  mysterious  photo- 
graphic reproductions  of  trees,  landscapes 
or  objects  in  the  neighborhood  at  the  time 
the  person  was  struck.  But  the  various 
figures  produced  doubtless  show  the  distri- 
bution of  the  high  potential  electricity  in 
passing  along  a  poor  conductor  and  the 
consequent  burning  along  a  ramifying  path. 

The  telephone  instruments  and  users  to 
a  large  extent  are  protected  by  use  of  a 
device — the  lightning  arrester.  This  con- 
sists of  a  ground  wire  coming  close  to  the 
telephone  wire  but  not  quite  touching  it. 
The  gap  between  is  enough  to  prevent  the 
current  used  in  telephoning  from  passing 
across  to  the  ground,  but  when  the  wire 
receives  a  high  charge  from  lightning,  the 
potential  is  so  high  that  the  charge  easily 
jumps  across  the  gap  and  passes  to  the 
ground  instead  of  passing  thru  the  instru- 
ment and  finding  some  other  passage  to  the 
earth.  You  will  observe  that  telephones 
properly  installed  in  your  homes  are  not 
placed  where  a  person  in  using  them  could 
at  the  same  time  make  contact  with  a 
register,  radiator,  or  water-pipe. — "G.  S.  Q." 


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•  July,  1917 


THE  ELECTRICAL  EXPERIMENTER 


213 


illed 


QUESTION  BOX. 

(Continued  from  page  212) 

solder    is    sometimes  erroneously 
spelter. 

Q.  2.  What  necessary  relation  must  ex- 
ist between  solder  and  the  metals  with 
which  it  is  to  unite? 

A.  2.  The  solder  must  have  a  lower  melt- 
ing point  than  the  metals  to  be  joined  to 
it.  The  melting  point  should  approach  as 
nearly  as  possible  that  of  the  metals  to  be 
joined,  so  that  a  more  tenacious  joint  is 
effected. 

Q.  3.  What  does  soft  solder  consist  of 
and  for  what  purpose  is  it  best  adapted? 

A.  3.  There  are  two  classes  of  soft 
•solders,  viz.,  common  or  plumber's,  and 
medium  or  fine.  These  consist  chiefly  of 
tin  and  lead,  altho  other  metals  are  oc- 
casionally added  to  lower  the  melting  point. 
Those  containing  the  most  lead  are  the 
cheapest  and  have  the  highest  melting 
point.  Common  or  plumber's  solder  con- 
sists of  one  part  of  tin  or  two  parts  of 
lead,  >and  melts  at  441°  Fah.  It  is  used 
"by  plumbers  for  ordinary  work,  and  oc- 
casionally for  electrical  work  where  wiped 
joints  are  required;  for  instance,  in  large 
lead-covered  cable  work.  Medium  or  fine 
solder  consists  of  equal  parts  of  tin  and 
lead,  or  half  and  half,  and  melts  at  370° 
Fah.  This  solder  is  used  for  soldering 
joints  in  copper  conductors,  and  for  solder- 
ing lead  sleeves  and  lead-covered  wires. 


ELECTRO-THERAPEUTICS. 

(811.)  Thomas  Holdstern,  Little  Creek, 
Mich.,  asks : 

Q.  1.  What  is  the  true  definition  of  the 
term  "electro-therapeutics"? 

A.  1.  The  term  electro-therapeutics  is 
defined  as  the  treatment  of  disease  by  elec- 
tricity ;  it  embraces  the  laws,  principles  and 
doctrines  of  such  treatment.  Electricity  is 
of  special  value  in  the  treatment  of  various 
forms  of  nerve  tension.  The  kinds  of  elec- 
tricity used  may  be  classed  as  follows  : 

1.  So-called  static,  generated  by  Wims- 
hurst  machines. 

2.  Current,  which  is  derived  from  two 
sources,  namely,  primary  batteries,  which 
current  is  technically  called  galvanic  cur- 
rent and  second  the  faradic  currents  (pro- 
duced by  secondary  induction  coils ) . 

3.  Radiant  energy,  which  is  generated  by 
radio-active  substances  such  as  radium  and 
radium  ores,  and  X-rays.  We  may  also 
add  the  curative  powers  of  radiant  energy 
generated  by  our  distant  sun. 

Q.  2.  What  is  meant  by  an  interrupter- 
less  transformer  as  used  in  X-ray  work? 

A.  2.  This  is  nothing  more  than  a  high- 
tension  rectifier  which  converts  the  high- 
tension  alternating  current  generated  by 
the  transformer  into  a  uni-directional  cur- 
rent which  is  fed  to  the  X-ray  tube.  This 
rectifier  is  a  four-electrode  wheel  rotating 
on  the  shaft  of  a  synchronous  motor,  and 
the  direct  current  is  obtained  from  two 
fixt  electrodes  stationed  near  the  revolving 
disc. 


GOVERNMENT  INSTALLS  LAMPS 
TO  PROTECT  OHIO  RIVER 
BRIDGES. 

The  Federal  Government  has  purchased 
ten  searchlights  for  use  in  illuminating  ap- 
proaches to  the  bridges  over  the  Ohio  River 
at  Louisville,  Ky.,  all  of  which  are  under 
guard.  Another  of  the  same  lamps  has  been 
installed  on  the  roof  of  the  City  Hall  in 
Louisville  and  is  used  to  illuminate  the  flag 
at  night. 


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PHILIP  EDELMAN,  Publisher 


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214 


THE  ELECTRICAL  EXPERIMENTER 


July,  1917 


Junior  Deaf-Phone  $15  c-^-e 

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THE  U.  S.  SIGNAL  CORPS  WANTS 
YOU! 

{Continued  from  page  179) 

providing  the  men  show  ability  and  qualify." 

The  following  information  is  publisht  to 
answer,  in  general,  inquiries  regarding  the 
Signal  Enlisted  Reserve  Corps.  The  En- 
listed Reserve  Corps  is  authorized  by  sec- 
tion 55  of  the  National  Defense  Act,  ap- 
proved June  3,  1916,  the  purpose  or  object 
being  to  secure  an  additional  reserve  of 
enlisted  men  that  could  be  brought  to  the 
aid  of  the  Government  in  time  of  national 
crisis.  Applicants  must  be  citizens  of  the 
United  States  or  have  declared  their  inten- 
tion to  become  such,  and  must  be  between 
the  ages  of  18  and  45  years. 

The  responsibilities  assumed  by  men  en- 
listed in  the  Reserve  Corps  are  as  follows  : — 
They  are  subject,  in  time  of  peace,  to  duty 
in  instruction  camps  or  elsewhere,  for  fifteen 
days  each  year.  They  are  subject  to  order 
to  duty  by  the  President  whenever  war  is 
actual  or  imminent. 

The  benefits  conferred  are  : — Opportunity 
to  render  their  most  effective  service  to 
their  country  in  time  of  war ;  opportunity  to 
prepare  for  that  work  beforehand  by  study 
and  instruction  ;  rank  in  the  Army  of  the 
United  States  and  corresponding  pay  while 
on  duty;  the  right  to  wear  a  distinctive 
"rosette"  or  "knot"  with  civilian  clothing. 

Enlisted  men  of  the  Reserve  Corps  will  be 
assembled  in  summer  camps  for  fifteen 
days'  instruction  each  year,  so  far  as  ap- 
propriations granted  by  Congress  will  per- 
mit. Transportation  to  and  from  these 
camps  is  furnished  by  the  Government,  also 
commutation  of  subsistence  at  the  rate  of 
50  cents  per  meal  during  the  journeys. 
While  at  the  camps  subsistence  is  furnished 
by  the  Government.  Uniforms  and  equip- 
ment are  also  provided  by  the  Government 
for  use  while  attending  the  camps  of  instruc- 
tion. Reservists  are  entitled  to  pay  at  the 
rate  of  their  respective  grades  in  the  Reg- 
ular Army  during  active  service,  including 
the  time  required  for  actual  travel  from 
their  homes  to  the  places  to  which  ordered 
and  return  to  their  homes. 

The  grades  and  monthly  pay  of  enlisted 
men  of  the  Signal  Reserve  Corps,  accord- 
ing to  the  new  schedule,  are  as  follows : — 

Master  signal  electrician  $81.00 

Sergeant,  first  class   51.00 

Sergeant    44.00 

Corporal    36.00 

Horseshoer    38.00 

Cook    38.00 

Private,  first  class   33.00 

Private    30.00 

The  following  are  the  general  qualifica- 
tions requisite  for  enlistment  in  the  Signal 
Enlisted  Reserve  Corps : 

A.  Master  Signal  Electrician.  The 
applicant  must  be — 

(a)  An  expert  telegrapher  and 
have  knowledge  of  the  con- 
struction, operation,  and  main- 
tenance of  telegraph  systems, 
primary  and  secondary  bat- 
teries, and  motor  generators, 
or — 

(b)  An  expert  radio  operator  and 
have  knowledge  of  radio  ap- 
paratus. 

(c)  Have  knowledge  of  the  con- 
struction, operation  and  main- 
tenance of  telephone  systems, 
switchboards,  location  of 
troubles,  repairs,  primary  and 
secondary  batteries,  motor 
generators,  or — 

(d)  Possess  such  qualities  as 
would  fit  him  to  act  as  senior 
non-commissioned  officer  of 
a  company  of  Signal  troops, 
to  act  as  a  leader. 


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July,  1917 

B.  Sergeant,  1st  Class.  The  applicant 
must  be — 

(a)  An  expert  telegrapher  and 
have  knowledge  of  the  opera- 
tion and  maintenance  of  tele- 
graph systems  and  batteries, 
or — 

(b)  An  expert  radio  operator  and 
have  knowledge  of  radio  ap- 
paratus, or — 

(c)  Have  knowledge  of  telephone 
systems,  switchboards,  bat- 
teries, locating  and  correcting 
faults,  etc.,  or — 

(d)  Possess  such  qualities  as 
would  fit  him  to  act  as  leader 
of  a  platoon  of  a  company  of 
Signal  troops. 

C.  Sergeants  and  Corporals.  The  ap- 
plicant must  have  general  knowledge 
of  the  subjects  given  under  B,  or 
possess  such  qualities  as  would  fit 
him  to  act  as  a  leader  of  a  platoon  or 
section  of  a  company  of  Signal 
troops. 

D.  Private,  1st  Class  and  Private. 
The  applicant  must  show  an  interest 
in  the  subjects  mentioned,  be  com- 
petent, keen,  and  possess  such  qual- 
ities as  will  insure  that  he  will  de- 
velop along  the  proper  lines  in  train- 
ing. 

Applicants  for  enlistment  as  Master  Sig- 
nal Electricians  and  Sergeants,  First  Class, 
will  be  given  an  oral  examination.  Appli- 
cants for  enlistment  in  the  other  grades  will 
demonstrate  to  the  officer  designated  to  ob- 
tain recruits  that  they  have  the  necessary 
qualifications.  Applicants  for  enlistment  in 
the  Eastern  Department  should  present 
themselves  at  39  Whitehall  St.  (near  the 
Battery),  New  York  City. 

LOCATING  AND  DESTROYING 
SUBMARINES  WITH  A 
RED  LIGHT  RAY. 

{Continued  from  page  165) 
right  angles  to  our  course  and  she  is 
thus  in  a  position,  broadside,  to  an  ob- 
server from  our  vessel;  that  is,  the  sub- 
marine is  presenting  the  greatest  sur- 
face of  her  hull  to  us  and  is  in  the  most 
favorable  position  for  the  visibility  from 
our  vessel,  if  she  can  be  rendered  so  by 
any  means. 

A  searchlight  operated  from  aloft  on 
our  ship  has  two  defects  which  prevent 
it  from  being  sucessfully  used  for  this 
purpose  as  a  submarine  detector. 

A  submarine  ready  to  fire  a  torpedo 
is  submerged  to  a  depth  of  some  fif- 
teen or  twenty  feet.  A  searchlight 
played  over  the  water  from  aloft  must  not 
only  find  the  horizontal  angle  of  the  sub- 
marine but  the  vertical  angle  as  well,  the 
area  being  too  great  to  admit  accomplish- 
ment of  this  object. 

Moreover,  the  ray  of  light  when  strik- 
ing the  water,  passing  from  a  light  medium 
(air)  to  the  denser  medium  of  water  causes 
a  glare,  due  to  the  refraction  which  forms 
an  opaque  cloud  to  the  observer,  obscur- 
ing everything  beyond  it. 

There  is  too  much  daylight  for  the 
searchlight  to  be  practical  during  the  day, 
the  time  when  attacks  are  made  by  sub- 
marines. 

However,  if  we  submerge  our  search- 
light or,  rather,  its  ray  of  light  to  a  depth 
of  fifteen  feet  by  installing  the  searchlight 
in  the  vessel  at  this  depth  below  the  water- 
line,  and  flash  a  powerful  beam  of  light, 
red  in  color  thru  a  thick  lens  of  glass 
in  the  ship's  side  and  out  into  the  water, 
we  obtain  several  distinct  advantages  over 
the  searchlight  operated  from  aloft. 

It  is  only  necessary  to  revolve  this  light 


THE  ELECTRICAL  EXPERIMENTER 


215 


thru  an  approximate  angle  of  90  degrees 
on  either  side  of  the  vessel  to  bring  a 
lurking  submarine  into  its  path,  for  the 
ray  is  already  in  the  proper  horizontal 
plane  beneath  the  surface  of  the  water. 

It  is  operating  only  in  one  medium,  water, 
and  the  opaque  glow  is  not  formed.  Its 
color  in  contrast  to  the  green  sea  enables 
it  to  be  seen  in  bright  daylight  as  a  slender 
reddish  path  extending  some  two  miles  out 
into  the  ocean  just  beneath  the  surface  of 
the  water. 

An  observer  with  a  powerful  telescope 
is  stationed  aloft,  whose  duty  it  is  to  ob- 
serve vigilantly  this  tract  of  crimson  as 
it  sweeps  slowly  back  and  forth  abreast  of 
the  ship. 

Suddenly  he  presses  a  button,  instantly 
arresting  the  revolution  of  the  beam  of 
light,  for  he  has  noted  that  the  ray  of 
light  does  not  extend  to  its  ordinary  limit, 
while  there  is  a  glare  of  blurred  light  form- 
ing what  may  be  termed  a  "bulge"  in  its 
path  and  he  realizes  instantly  that  the 
beam  of  light  has  encountered  a  non-trans- 
parent body  which  is  refracting  the  ray. 

The  alarm  is  sounded  and  the  gun  battery 
trained  on  the  spot  indicated.  One  or  two 
shots  will  destroy  the  menace  and  the  ves- 
sel may  divert  her  course  to  clear  it. 

All  that  is  necessary  to  insure  the  suc- 
cess of  this  method  is  the  perfection  of  a 
searchlight  of  sufficient  power  and  an  ex- 
perienced observer. 

The  public  may  confidently  anticipate  the 
rapid  development  of  this  system  of  de- 
fence, which  will  prove  not  only  a  mortal 
blow  to  the  submarine  but  a  benefaction 
to  all  humanity.  The  device  here  described 
is  easily  adaptable  to  either  naval  or  com- 
mercial ships  and  a  vessel  may  conveniently 
carry  four  search-lights  of  this  type — two 
forward  and  two  aft ;  one  on  either  side 
of  the  hull  in  both  positions. 

DOES  RADIANT  LIGHT  POSSESS 
WEIGHT? 

{Continued  from  page  168) 
mysteries.  Briefly,  he  allowed  a  beam  of 
light  to  fall  on  a  suspended  disc  in  a  vacuum 
bulb,  exhausted  to  the  highest  degree.  In 
such  a  vacuum  the  disc  was  repelled  on  the 
impact  of  a  light  beam,  and  its  repulsion 
was  measured  by  its  torsional  effect  on  the 
suspending  wire.  This  light-pressure  at  the 
distance  of  the  earth  from  the  sun  is  small, 
not  quite  a  milligram  per  square  metre  of 
the  earth's  surface,  or  roughly,  70,000 
tons  on  the  whole  earth.  The  light-pressure 
is  applied  only  on  the  surface,  and  is  pro- 
portional to  the  surface,  while  weight,  or 
the  pull  of  gravitation,  affects  the  whole 
body.  The  adherents  to  the  electro-mag- 
netic wave  theory  of  light  have  some  diffi- 
culty in  explaining  this  pressure,  as  it  seems 
impossible  to  conceive  of  a  mere  wave-form 
in  the  ether  exerting  a  material  force  or 
pressure  on  the  earth.  If  light  were  con- 
sidered a  material  substance,  however,  the 
above  phenomenon  could  be  more  plausibly 
explained,  as  due  to  the  effect  of  gravita- 
tion on  a  tangible  substance. 

There  are  many  interesting  facts  to  be 
obtained  on  the  chemical  and  physical  ef- 
fects of  light,  and  in  respect  to  this  side  of 
the  problem  there  are  many  opportunities 
for  research  work,  which  might  result  in 
the  solution  of  the  mystery  as  to  the  na- 
ture of  light.  Below  are  given  a  very  few 
of  the  instances  in  which  the  elements  are 
acted  upon  by  the  strange  force  of  light : 
(1)  Nitric  acid  is  readily  decomposed  by 
light.  (2)  Silver  chlorid,  silver  iodid  and 
silver  bromid  are  all  chemically  changed 
on  exposure  to  light.  (3)  Silver  nitrat  in 
the  presence  of  organic  matter,  looses  its 
oxygen  and  is  reduced  to  the  metallic  state 
by  the  action  of  light.  (4)  Mercuric  oxid 
is  decomposed  by  light.     (5)  The  chlorids 


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Name 
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0RS 


T 

1  GREAT 
OPPORTUNITY! 


We  havo  the  following  listed  motors  in 
stock.  We  are  discontinuing  these  sizes 
and  offer  them  now  BELOW  COST.  If  you  need  a 
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These  are  all  for  110  volts  direct  current.  Further 
particulars  may  he  had  by  applying  to  the  undersigned. 
3— liH.P.  D.  C.  110  volts,  each  $19.00;  list  price, 
$24.00.  3—  '/8H.P.,  D.  C.  110  volts,  each  $9.00:  list 
price.  $15.00.  I— '2H.P..  D.  C,  110  volts,  each  $37.00: 
list  price.  $46.50.  I  — I/I6H.P.,  D.  C,  110  volts,  each 
$7.00:  list  price,  $9.00. 


Loo 


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J£  231  Fulton  St.,  New  York  City,  N.  Y. 


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Drive  and  demonstrate  the  Bush  Car.  Fay  lor  11  oui  oi 
your  commiMioDi.on.aleB.  My  w.i.UueimkmBn.w.  Ship- 

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Dept.  141 
Delco  Ignition— Elect.  Stg.  &  Ug. 
BTJSH  MOTOR  COMPANY,  Bosh  Templet  Chicago,  UUaota 


PRO-ALLY  or  PRO-MOTION? 

WHICH  ARE  YOU  FOR? 

You  can't  settle  this  war,  but  you  CAN  settle  your 
future!  Are  you  FOR  yourself?  Or  AGAINST  your- 
self? "Pro"  means  "for" — are  you  FOR  promotion 
that  will  move  you  out  of  the  rut  and  into  the  place 
higher  uj> — where  you'd  like  to  be? 

"Motion-'  means  "action."  Pro- 
motion means  action  that  gets  some- 
where. You  can't  have  action  with- 
out HEALTH,  VITALITY  anil 
STRENGTH.  You  MUST  have  these 
to  go  forward  and  up  I 

A  clam  has  motion — just  enough  to 
ooze  'round  in  the  mud.  Its  only  pro- 
motion is  to  the  chowder.  Don't  be  a 
clam!  Be  a  MAN  with  vigor  and 
purpose  of  manhood.  Let  me  show 
you  HOW!  By  the  same  methods 
that  I  became  the  strongest  man  in 
the  world,  I  can  teach  you  also. 

If  you  are  suffering  from  any  ail- 
ment then  mark  it  on  the  coupon 
below.  Or  if  you  are  paying  the 
penalty  of  early  indiscretion,  write 
and  tell  me  all  about  yourself.  It 
will  be  in  confidence.  I  can  help 
YOU  as  I  have  helped  others.  I 
can  not  only  show  you  the  way  to 
bigger  things,  but  I  can  give  you 
the  power  to  GET  them.  Write  to- 
day for  my  book,  "Intelligence  In 
Physical  and  Health  Culture."  It 
will  be  an  eye-opener  to  you  as  to 
what  you  are,  and  what  you  CAN  be. 

LIONEL  STRONGFORT 

PHY'SICAL  CULTURE  SPECIALIST 
175  Park  Bldg.  Newark,  N.  j. 

FREE   CONSULTATION  COUPON 

Dear  Strongfort — Please  send  me  your  book  "IN- 
TELLIGENCE IN  PHYSICAL  AND  HEALTH  CUL- 
TURE," for  which  I  enclose  5  cents  for  postage. 

I  have  marked  (X)  before  the  subject  in  which  I  am 
Interested  and  should  like  you  to  send  me  a  personal 
talk  on  this  subject.  175  Park  Bldg. 

.  .Thinness  .  .Rheumatism        .  .Despondency 

.  .Obesity  .  .Heart weakness    .  .Poor  Memory 

.  .Nervousness         .  .Headache  .  .General  Health 

.  .Insomnia  .  .Skin  Disorders    .  .Increased  Height 

.  .Indigestion  .  .Round  Shoulders.  .Muscular 

. .  Constipation  . .  Stoop  Shoulders  Development 
.  .Short  Wind         .  .Deformity  .  .Great  Strength 

.  .Flat  Chest  .  .Rupture  .  .Weight  Lifting 

.  .Colds  .  .Youthful  Errors  .  .Advanced  Course 

.  .Catarrh  .  .Devitalizing       .  .Multi-Weight 

.  .Lung  Trouble  Losses  Barbell 

.  .Poor  Circulation  .  .Impotency 

Name   

Street  

City    State   


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216 


THE  ELECTRICAL  EXPERIMENTER 


July,  1917 


WIRELESS 

for  the  College  or  Prep.  School 
man,  High  School  graduate,  etc. 
The  U.  S.  Gov't  needs  you  in  its 
Naval  Reserve,  Naval  Militia 
and  Signal  Corps. 
Attractive  openings.  Special 
three  months'  Summer  course 
starting  June  25th  prepares  you 
for  either  Gov't  or  Commercial 
Service.  Endorsed  by  U.  S.  Gov't 
and  Marconi  Co.  Day  and  Eve- 
ning classes. 

SEND  FOR  SPECIAL  LITERATURE. 

EASTERN  RADIO  INSTITUTE 

899B  Boylston  St.  Boston 


LEARN 

WIRELESS 

This  summer 

THOUSANDS  of  operators  are  urgently 
needed  by  the  Government.  In  war  and 
peace  the  demand  has  always  greatly  ex- 
ceeded the  supply.  Unusual  opportunities 
therefore  await  the  well  trained  Radio  Men. 

Although  we  have  trained  more  operators 
than  any  other  private  school  in  the  East, 
we  can  supply  only  one-tenth  of  the  demand 
made  upon  us. 

New  Day  and  Evening  Classes  forming 
this  month — Reasonable  Rates — Large  Labo- 
ratory— Complete  Commercial  Installations. 

U.  S.  GOVERNMENT  INSTRUCTORS 

Dormitories        Catalogue  Employment 

Y.  M.  C.  A.  Radio  School 

145  East  86th  Street         NEW  YORK,  N.  Y. 


ELECTRICAL  Je»»«l.      Having   trained  over 
■  ^ "  "        2IMKI  y<.unB  men  in  the  past  23 

years  in  the  fundamentals  of  Applied  Electricity,  THK  Bliss  ELtXTKi- 
CAL  School,  with  it3  well-equipped  shops  and  laboratories,  is  peculiarly 
well  qualified  to  give  a  condensed  course  in  Electrical 


ENGINEERING 

Including  Mathematics,  Steam  and  Gas  En. 
Kines.  Mechanical  Drawing,  Shop  Work  and 
Theoretical  and  Practical  Electricity,  in  all 
branches.  Students  actually  construct  dyna- 
mos, install  wiring  and  teat  efficiency  of 
electrical  machinery.  Course,  with  diploma, 
complete 

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and  iodids  of  mercury  and  thallium  are 
decomposed  by  light.  (6)  Upon  heating 
nitrogen  chlorid  and  nitrogen  bromid  in 
sunlight,  the  mixture  explodes  with  violence. 
(7)  A  balloon  containing  hydrogen  and 
chlorin  will  burst  when  exposed  to  the 
sun's  rays.  (8)  Selenium  lowers  its  elec- 
trical resistance  when  exposed  to  light.  (9) 
In  the  Crooke's  Radiometer  the  pressure 
of  light  causes  a  multi-blade  vane  or  wheel 
to  rotate  in  a  vacuum. 

It  will  be  noticed  in  the  cases  cited  above 
that  the  group  of  elements  known  as  the 
Halogens,  particularly  the  silver  salts,  are 
affected  by  the  action  of  light,  which  acts 
in  most  instances  like  a  reducing  agent. 
Why  the  silver  salts  are  singled  out  from 
all  the  other  compounds  and  made  an  ob- 
ject of  attack  by  the  force  of  light  is  diffi- 
cult to  explain  by  the  ether-wave  theory. 
But  if  light  were  taken  to  be  a  gas,  the 
above  phenomenon  would  be  more  easily 
understood  by  the  simple  fact  that  light 
is  then  a  reducing  agent.  The  light-gas 
theory  must  thus  assume  that  light  pos- 
sesses properties  similar  to  other  gases, 
such  as  chemical  afhnity,  a  definite  valency, 
or  possessing  the  power  of  a  catalytic 
agent.  Such  properties  appear  to  be  con- 
sistent within  the  chemical  effects  of  light 
as  shown  above. 

As  is  well  known,  the  element  Selenium 
possesses  the  peculiar  property  of  chang- 
ing (lowering)  its  electrical  resistance  ac- 
cording to  the  intensity  of  the  light  cast 
upon  it,  and  this  strange  phenomenon  has 
been  a  strong  argument  against  the  wave 
theory,  as  it  is  almost  impossible  to  con- 
ceive of  the  so-called  ether  waves  produc- 
ing such  a  tangible,  material  effect.  Sev- 
eral theories  have  been  advanced  to  ex- 
plain this  behavior  of  light.  One  is  the 
formation  of  conducting  selenids  under  the 
action  of  light.  Another,  the  formation 
of  conducting  crystals.  Still  another,  that 
it  is  due  to  electrolytic  action  and  finally 
the  electronic  theory  which  assumes  the 
releasing  of  negative  electrons,  due  to  vibra- 
tary  resonance  in  the  atoms. 

Again,  it  has  been  demonstrated  that 
light  has  a  strong  effect  on  bacteria,  such 
as  ferments.  At  the  Paris  Exhibition  in 
1900,  the  powerful  results  of  light  were 
forcefully  illustrated  by  the  culture  of 
pathogenic  bacteria  in  gelatin  in  glass  bot- 
tles. Portions  of  the  bottles  were  covered 
with  dark  paper,  the  bottles  incubated  at 
suitable  temperatures  in  bright  sun-light 
and  the  contents  afterwards  completely 
sterilized.  Wherever  the  dark  paper  had 
prevented  light  action,  dense  colonies  of 
bacteria  could  be  seen,  while  in  exposed 
parts  the  nutrient  gelatin  remained  per- 
fectly clear.  Here  again,  light  acts  as  a 
gas,  for  it  can  be  easily  shown  that  sev- 
eral gases  such  as  oxygen,  exert  an  in- 
fluence on  the  growth  of  bacteria.  Only 
a  strong  imagination  could  attribute  these 
results  to  wave  forms  in  the  ether,  it  would 
seem. 

In  concluding,  it  may  be  well  to  take 
up  the  question  of  the  speed  of  light  and 
its  relation  to  any  of  the  accepted  the- 
ories. The  speedy  of  light  has  been  definitely 
accepted  and  proven  as  186,000  miles  per 
second,  and  this  tremendous  velocity  has 
been  for  years  a  strong  objection  to  the 
corpuscular  or  material  theory,  as  it  was 
unbelievable  that  any  material  form  of 
matter  could  attain  such  terrific  velocity. 
Of  late  years,  however,  there  has  been 
much  progress  made  in  the  study  and  be- 
havior of  X-rays  and  radium  emanations ; 
and  it  has  been  conclusively  proven  by 
means  of  mathematics  that  the  speed  of 
the  corpuscles  emitted  by  metals  under  the 
impact  of  ultra-violet  light,  may  be  taken 
as  anywhere  from  10,000  to  90,000  miles 
per  second;  and  it  may  also  be  stated  that 
these  corpuscles  are  material  atoms  of  mat- 


ter for  their  individual  weights  have  been 
actually  determined  by  mathematics. 

In  regards  to  the  Alpha,  Beta  and  Gam- 
ma-rays emitted  by  radium,  it  has  been 
conclusively  proven  that  the  Alpha  rays 
are  streams  of  little  bodies  (matter)  with 
a  mass  about  twice  the  mass  of  the  hy- 
drogen atoms,  flying  off  from  radium  with 
a  velocity  of  20,000  miles  per  second,  while 
the  Beta-rays  given  off  by  this  innocent- 
looking  little  pinch  of  salt,  are  actual 
material  corpuscles,  with  a  known  weight, 
and  a  speed  of  over  100,000  miles  per  sec- 
ond. This  is  now  regarded  as  an  estab- 
lished fact,  and  such  being  the  truth,  it 
is  much  easier  to  believe  that  a  gas,  such 
as  light  may  be,  could  attain  a  velocity 
of  186,000  miles  per  second,  and  still  be 
within  the  bounds  of  material  matter. 

As  will  be  noticed,  it  was  the  author's 
object  to  present  a  few  arguments  in  favor 
of  the  material  theory,  and  altho  this  the- 
ory has  not  come  into  general  acceptance 
by  scientists,  it  is  gradually  gaining  ground, 
and  from  the  researches  being  made  on 
radium  emanations  and  all  forms  of  radio- 
activity, it  appears  that  the  electro-mag- 
netic-wave theory  of  light  may  have  to 
be  confined  to  more  reasonable  realms ; 
it  may  well  serve  to  explain  wireless- 
telegraphy  and  such  wave-activities,  but  the 
strange,  material  force  known  as  "Light" 
certainly  demands  a  more  consistent  explan- 
ation in  view  of  its  chemical  effects. 


U.  S.  BATTLESHIPS  TO  RUN  ON 
LAND. 

(Continued  from  page  170) 

ner.  The  steering  is  equally  simple  and 
efficient.  By  running  one  motor  at  a  slight- 
ly higher  or  lower  speed,  the  ship  must 
either  turn  to  the  right  or  to  the  left, 
as  desired  by  its  commander. 

I  have  pointed  out  in  previous  articles, 
that  the  monster  wheel  is  the  prime  re- 
quisite of  all  large  war  machines.  A  huge 
wheel,  such  as  the  ones  here  described, 
will  easily  ride  over  the  widest  trenches. 
Ordinary  shell  holes  will  be  negotiated  as 
easily  as  a  cart  wheel  runs  over  a  hole  in 
the  street  due  to  a  missing  cobblestone. 
Rivers  will  be  forded  easily,  if  there  is  a 
fair  approach.  Even  steep  banks  will  be 
negotiated  by  running  the  craft  diagonally 
thru  the  stream.  Low  hills  will  prove  no 
obstacle  at  all,  while  steeper  ones  can  be 
climbed  by  running  the  ship  in  a  zig-zag 
line. 

There  will  be  less  wear  and  tear,  and 
less  shocks  too  when  running  over  land 
than  when  fording  a  tempestuous  sea.  The 
reason  is  that  these  huge  wheels,  just  on 
account  of  their  size,  are  rather  elastic. 
They  "give"  a  good  deal.  Then  too,  the 
earth  as  a  rule  is  more  or  less  soft.  Thus 
we  get  a  double  spring  action.  Also  due 
to  the  enormous  width  of  the  wheels — dis- 
tributing the  weight  over  a  wide  area — 
they  will  not  sink  into  the  softest  earth 
much  more  than  a  few  inches.  This  may 
seem  surprising,  but  a  simple  calculation 
which  any  engineer  may  make  in  a  few 
seconds,  will  prove  the  statement  correct. 

It  goes  without  saying  that  in  order  to 
carry  the  enormous  strain,  the  ship  must 
be  strengthened  by  a  good  deal  of  cross- 
truss  steel  work,  as  indicated  in  our  illus- 
tration. Otherwise  the  shaft  would  rip 
clear  thru  the  decks.  This  truss  work, 
however,  should  not  prove  over  difficult, 
nor  a  very  long-winded  operation.  The 
reader  has  already  guest  that  no  new 
power  plant  is  required.  The  old  one  is 
of  course  utilized,  the  ship  burning  coal 
the  same  as  if  it  were  on  the  ocean. 


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July,  1917 


THE  ELECTRICAL  EXPERIMENTER 


217 


From  a  military  standpoint,  this  mon- 
ster engine  of  destruction  proves  rather  in- 
teresting. But  let  us  see  what  happens 
when  the  "Oregon,"  one  fine  summer  morn- 
ing steams  thru  the  French  fields,  "Old 
Glory"  flying  from  hoth  masts,  and  plow- 
ing toward  the  German  trenches.  No  more 
thrilling  or  awesome  picture  could  be  im- 
agined. Of  course  long  ere  our  battle- 
ship has  reached  the  first  trenches,  the 
enemy  aeroplanes  have  reported  it,  and 
the  "Oregon"  receives  a  warm  welcome 
from  the  heavy  enemy  guns.  But  this 
is  just  what  we  want.  After  finding  the 
range  of  the  enemy  guns,  our  battleship's 
10-inch  guns  can  either  silence  the  enemy 
or  otherwise  run  towards  the  German  bat- 
tery and  crush  it  by  simply  running  over 
it.  There  is  no  escape  for  them,  for  we 
have  the  advantage  of  quick  mobility  (the 
ship  runs  from  15  to  18  miles  per  hour) 
against  the  slow  mobility  of  the  enemy 
guns,  which  cannot  be  moved  quickly. 
After  annihilating  these,  the  land  monster 
runs  amuck,  destroying  ammunition  dumps, 
and  raising  general  havoc  behind  the  lines. 
Small  guns  and  machine  guns  prove  of 
little  use  against  our  armored  battleships, 
and  even  if,  as  is  to  be  expected,  enemy 
shells  find  their  mark,  they  cannot  "sink" 
us  or  stop  us.  For  the  engines  as  well 
as  all  other  vital  parts  are  protected  by 
heavy  armor.  The  wheels  themselves  will 
not  be  put  out  of  running  order  easily, 
because  they  are  not  solid.  The  shells, 
even  if  they  do  hit,  will  hardly  destroy 
the  entire  wheel.  Beyond  ripping  out  a 
few  steel  beams,  no  great  damage  will  be 
done. 

The  "Oregon"  now  runs  over  and  par- 
allel the  trenches,  the  battleship's  well  pro- 
tected machine  guns  emplaced  low  down 
in  the  holds,  firing  away  continuously.  The 
result  is  that  the  enemy  must  give  way. 
If  several  battleships  are  used  simultan- 
eously in  a  grand  attack,  there  is  no  ques- 
tion that  the  enemy  must  fall  back  over 
a  wide  area. 

And  it  will  be  impossible  for  the  enemy 
to  board  the  swiftly  moving  vessel.  Even 
if  forced  to  stand  still,  its  machine  guns 
and  other  guns  would  ward  off  all  close 
attacks. 

There  remains  the  aeroplanes  dropping 
bombs  into  the  ship.  The  answer  here 
would  be — anti-aeroplane  guns,  installed _al- 
ready  on  every  modern  war-ship.  Besides 
our  own  aeroplanes  would  protect  the  ship 
by  beating  off  the  enemy  flyers. 


"HAM"  JONES— SCIENTIST. 

{Continued  from  page  181) 
As  we  approached  the  curtain  he  spied 
a  pair  of  pliers,  and  said,  "By  the  way, 
you  see  how  the  cutting  edges  of  these 
pliers  are  fused?  Well,  several  days  ago 
I  cut  a  lamp  cord  with  them.    The  current 


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THE  ELECTRICAL  EXPERIMENTER 


July,  1917 


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was  on,  and  I  cut  both  wires  at  once.  There 
was  some  great  fireworks,  but  those  new 
fuses  of  mine  held  first  rate."  Then  he 
laid  them  reverently  upon  the  top  of  the 
helix. 

"Hen"  told  me  all  about  the  mechanism 
of  the  curtain  and  then  towed  me  back  to 
the  bed  to  show  how  he  "turned  in"  and 
"hit  the  hay."  It  seems  he  did  not  use 
the  curtain  arrangement  very  often,  for 
it  had  a  habit  of  rising  before  the  desired 
time ;  however,  all  was  ready  for  the  dem- 
onstration. "Hen"  was  supposed  to  have 
said  his  prayers  and  be  snugly  tucked  un- 
der the  covers. 

"Watch  out,"  he  warned,  "while  I  press 
button  number  one."  So  he  prest  it  and 
with  a  click  the  latch  gave  away  and  the 
door  swung  open. 

"Now  for  number  two,"  cried  "Hen." 
"Watch  the  curtain.  This  is  the  best  of 
the  whole  bunch!"  Twang  went  the  spring 
of  the  curtain  and  up  went  the  latter  with 
a  bang,  but  on  its  upward  journey  it  struck 
the  end  of  the  pliers  which  "Hen"  had  left 
sticking  over  the  edge  of  the  helix ;  the 
pliers  sailed  over  toward  the  110-volt 
switchboard  and  thereupon  there  occurred 
a  series  of  twangs  and  bangs  intermingled 
with  shooting  stars  and  meteors — then 
something  gave  away  and  the  Jones'  house 
was  plunged  in  total  darkness ! 

"What  the  deuce!"  cried  "Hen",  in  alarm, 
and  very  undignified.  "Wouldn't  that  make 
yer  mad?" 

From  below,  on  the  second  floor,  there 
came  in  a  stentorian  voice,  a  series  of  in- 
terrogations, ejaculations  and  commenta- 
tions which  only  served  to  add  terror  to 
an  already  fluttering  heart — so  while  "Ham" 
Jones  hunted  around  in  the  dark  for  a 
ten-penny  nail  with  which  to  form  a  1918 
model  Jones'  Unblowable  Fuse  (Patents 
Pending)  I  slunk  down  two  flights  of  stairs 
and  ran  home  as  fast  as  I  could. 


AMATEUR  AND  EXPERIMENTAL 
RADIO  RESEARCH. 

(Continued  from  page  201) 

Apparatus  Necessary  for  Research  Work. 

While  a  well-equipt  radio  experimental 
laboratory  is  a  great  asset  in  research  work, 
it  is  by  no  means  an  absolute  necessity. 
By  means  of  the  ordinary  amateur  equip- 
ment, together  with  a  few  easily  made  ac- 
cessories, one  can  do  much  experimental 
work  of  a  very  useful  and  penetrating 
nature.  There  are  certain  research  prob- 
lems, of  course,  that  would  demand  elab- 
orate apparatus  to  work  with,  but  this  is 
not  generally  true. 

The  amateur  who  wishes  to  do  experi- 
mental work  should  equip  his  station  with 
a  certain  amount  of  auxiliary  apparatus. 
He  should  first  wind  several  loading  coils 
and  inductances  of  various  sizes.  These 
coils  should  be  labeled  as  to  the  number 
of  turns  they  contain  and  the  wave-length 
they  should  respond  to  (or  better  still,  cal- 
culate or  measure  the  inductance  in  centi- 
meters of  each  coil  as  explained  in  the 
series  by  Secor  and  Cohen  published  in  the 
March  and  April  issues  of  this  journal), 
as  it  is  always  best  to  know  just  what 
one  is  working  with.  Aside  from  these, 
several  variometers  of  different  sizes 
should  be  constructed,  as  they  are  almost 
indispensable  in  work  of  this  nature.  It 
is  not  necessary  to  build  an  elaborate  cab- 
inet for  the  variometers,  as  they  can  be 
placed  inside  a  square  framework,  which 
is  just  as  good.  On  each  variometer  there 
should  be  a  single-pole  switch,  connected 
across  the  terminals  so  the  instrument  can 
be  quickly  eliminated  from  the  circuit  if 
desired.  At  least  three  receiving  trans- 
formers  should   also  be   included  in  the 


equipment  and  these  should  be  of  various 
dimensions  capable  of  responding  to  a  wide 
range  of  wave  lengths.  It  is  also  desirable 
to  build  several  fixt  receiving  condensers 
of  various  capacities  and  each  one  equipt 
with  a  shorting  switch.  Detectors  of  vari- 
ous types  should  also  be  on  hand,  as  it 
must  be  remembered  that  certain  crystals 
are  better  adapted  for  some  work  than 
others.  The  Audion  is  not  an  absolute 
necessity  unless  it  is  desired  to  experiment 
with  this  particular  instrument  for  regen- 
erative work,  etc.  It  might  be  said  here 
that  the  Audion  and  its  circuits  offer  a  very 
fruitful  line  of  research.  At  least  three 
variable  condensers  should  be  included  in 
an  experimental  outfit,  as  they  are  very 
necessary  additions,  absolutely  essential  for 
real  serious  work. 

'  Probably  the  most  important  considera- 
tion in  wireless  research  work,  especially  in 
regard  to  receiving,  is  the  rapid  change  of 
connections.  Experimental  apparatus 
should  be  as  flexible  as  possible.  The  sim- 
plest way  to  accomplish  this  is  to  build  a 
small  switch-board  and  this  should  contain 
a  number  of  single  point  switches,  D.  P. 
S.T.,  D.  P.  D.  T.,  and  multipoint  switches. 
The  points  and  blades  of  the  switches 
should  "be  connected  directly  to  binding 
posts  on  the  back  of  the  board.  There 
should  also  be  a  row  of  binding  posts  fixt 
along  the  top  of  the  board,  as  it  is  often- 
times found  convenient  as  well  as  necessary 
to  use  such  an  arrangement. 

The  transmitting  outfit  should  be  equipt 
with  several  inductances,  both  loose  and 
close  coupled,  of  various  dimensions  and 
known  values.  A  rotary,  quenched  and 
series  spark  gap,  together  with  a  large  con- 
denser with  removable  plates  or  other 
means  of  capacity  variation  should  also  be 
included.  If  experiments  in  radiation  are 
to  be  conducted,  it  is  of  course  necessary 
to  either  construct  or  purchase  a  reliable 
hot-wire  ammeter.  The  problem  of  pro- 
viding means  for  the  rapid  changing  of 
connections  in  the  transmitting  apparatus 
is  not  as  necessary  as  in  the  case  of  the 
receiving  equipment.  Furthermore,  the  con- 
nections are  not  so  complicated.  A  few 
heavy  switches  may  be  added  to  the  sending 
equipment,  as  they  are  found  to  be  useful 
in  many  cases.  Valuable  research  work 
can  be  carried  on  in  the  laboratory  by 
means  of  a  buzzer  transmitter,  together 
with  a  wave  meter  and  a  dummy  or  load- 
ing antenna.  This  is  formed  of  a  compact 
coil  of  resistance  wire,  designed  to  have 
the  proper  radiation  resistance,  inductance 
and  capacity,  and  corresponding  to  a  fair 
size  antenna.  These  are  available  in  the 
market  and  those  interested  will  receive 
information  concerning  them  by  writing  to 
the  Editor,  Radio  Department,  enclosing  a 
stamped  and  addrest  envelope.  Most  com- 
mercial radio  transmitters  are  tested  out  to- 
day on  a  phantom  aerial  or  load,  as  they 
are  sometimes  termed.  See  article  else- 
where in  this  issue  on  the  "load"  or  dum- 
my antenna  used  by  the  Federal  Telegraph 
Company.    (See  page  186.) 

The  suggestions  offered  above  only  deal 
with  a  general  equipment  for  research 
work,  and  there  will,  of  course,  be  many 
instances  where  the  experimenter  will  have 
to  use  his  own  judgment  in  building  instru- 
ments of  special  design  to  carry  out  his 
ideas.  The  only  suggestion  of  worth  that 
can  be  offered  in  this  way  is  to  work  care- 
fully and  neatly,  as  results  cannot  be  ex- 
pected from  a  piece  of  apparatus  that  is 
"thrown"  together.  Altho  it  is  not  neces- 
sary to  build  elaborate  experimental  instru- 
ments, they  should  be  neatly  and  substan- 
tially made,  as  it  may  be  that  a  poorly  con- 
structed instrument  may  defeat  an  impor- 
tant and  valuable  experiment  that  would 
otherwise  prove  successful.  Part  II  will 
take  up  "Suggestions  for  Research  Work." 


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July,  1917 


THE  ELECTRICAL  EXPERIMENTER 


219 


Edited  by  H.  GERNSBACK 

In  this  Department  we  publish  such  matter  as  is  of  interest  to  inventors  and 
particularly  to  those  who  are  in  doubt  as  to  certain  Patent  Phases.  Regular  inquiries 
addrest  to  "Patent  Advice"  cannot  be  answered  by  mail  free  of  charge.  Such  inquiries 
are  publisht  here  for  the  benefit  of  all  readers.  If  the  idea  is  thought  to  be  of  im- 
portance, we  make  it  a  rule  not  to  divulge  details,  in  order  to  protect  the  inventor  as 
far  as  it  is  possible  to  do  so. 

Should  advice  be  desired  by  mail  a  nominal  charge  of  $1.00  is  made  for  each 
question.  Sketches  and  descriptions  must  be  clear  and  explicit.  Only  one  side  of 
sheet  should  be  written  on. 


THAT  BELL  SOFTENER. 

(160)  The  Editor  sometime  ago  in  an 
Editorial  entitled  "Inventions  Wanted," 
mentioned  that  there  existed  a  large  market 
for  an  appliance  which  would  take  the  dis- 
agreeable jar  out  of  the  telephone  bell.  This 
editorial  was  consequently  publisht  broad- 
cast by  dozens  of  newspapers  and  periodi- 
cals. Since  then  hundreds  upon  hundreds 
of  letters  reached  the  Editor's  desk,  nearly 
all  the  writers  wishing  to  know  who  would 
buy  such  an  invention. 

Frankly,  we  do  not  know  of  any,  off- 
hand. Altho  we  are  certain  that  if  a  really 
good  appliance,  which  fills  the  bill,  is  in- 
vented, there  are  a  number  of  electrical 
manufacturers  and  telephone  manufacturers 
who  certainly  would  want  to  buy  the  patent. 
But,  like  all  good  things,  nothing  sells  it- 
self. There  was  a  positive  demand  for  the 
telephone,  long  before  it  was  invented,  but 
everybody  knows  of  the  long,  bitter  fight 
that  Bell  had,  trying  to  introduce  his  tele- 
phone. It  is  the  same  with  almost  any  in- 
vention. After  you  make  it,  the  fight  to 
realize  on  it,  begins.  If  you  have  something 
really  good,  you  will  make  more  money  in 
the  long  run  by  marketing  it  yourself. 

Another  thing :  When  the  Editor  sug- 
gested the  "Bell  softener"  he  did  not  have 
some  sort  of  a  muffler  in  mind  at  all,  as 
most  correspondents  seem  to  think.  Muf- 
fling the  gongs  does  not  solve  the  problem. 
•Take  the  gongs  off  and  substitute  something 
that  is  not  a  gong.  Wooden  or  similar 
gongs  won't  do.  Substitute  rather  something 
giving  a  musical  pleasing  note,  soft  and  mel- 
low, which  however  should  not  be  harsh  or 
abrupt.  It  is  the  abruptness  of  the  telephone 
bell  which  gets  on  one's  nerves. 


MAGAZINE  PENCIL. 

(161)  Morton  Gross  of  Chicago  has 
submitted  to  us  an  idea  of  a  pencil  which 
requires  no  sharpening.  It  is  made  of  paper, 
but  embodies  a  totally  different  construc- 
tion than  the  present  paper  pencils  on  the 
market.    Our  advice  is  asked. 

A.  An  extraordinary  good  idea,  as  good 
as  it  is  novel.  It  also  seems  to  us  that  it 
could  be  manufactured  cheaper  than  the 
present  patent  ones.  We  feel  certain  that  a 
good  patent  can  be  obtained. 


OSCILLATING  DEVICE. 

(162)  William  Woodward,  Wilmette, 
111.,  submits  sketch,  an  illustration  of  a  novel 
device  for  making  a  damped  hookup  oscil- 
late. Is  the  device  practical  and  can  it  be 
patented  ? 

A.  The  scheme  looks  eminently  prom- 
ising on  paper,  but  without  necessary  re- 
search work,  we  would  not  be  willing  to 
give  a  final  opinion.  We  advise  our  corre- 
spondent to  try  it  out  by  building  a  model. 
If  it  works,  as  described,  a  valuable  patent 
will  result.  We  have  never  seen  anything 
just  like  it. 


COVER  LIFTING  DEVICE. 

(163)  A.  J.  Walrath,  Detroit,  Mich.,  has 
sent  us  a  description  and  illustration  of  a 
clever  automatic  cover  lifting  device  at- 
tachable to  garbage  -cans  or  ash  cans.  Is  it 
patentable  and  practical? 

A.  A  capital  idea.  Something  that 
should  appeal  to  every  housekeeper  and  to 
every  janitor.  Moreover,  the  device  can  be 
manufactured  very  cheaply,  and  sold  at  a 
low  price.  We  think  it  extremely  practical 
and  we  believe  a  patent  can  be  obtained 
upon  the  device. 


INSULATOR. 

(164)  Harry  J.  Wright,  Jr.,  North  Van- 
couver, B.  C,  Canada,  submits  an  insulator 
for  outdoor  wiring.  This  insulator  uses 
two  nails  which  are  placed  in  such  a  man- 
ner that  the  insulator  is  not  easily  pulled 
away  from  its  support  during  storms,  or 
when  sleet  settles  upon  the  wire. 

A.  A  very  good  and  a  very  cheap  in- 
sulator. There  is  only  one  objection  and 
that  is  that  the  insulator  will  crack  when 
the  nails  are  driven  home,  due  to  the  fact 
that  only  one  point  of  the  nails  touch  the 
top  of  the  insulator.  If  the  top  is  made  at 
an  angle,  so  that  the  nails  will  meet  the  sur- 
face at  right  angles,  a  much  better  insulator 
will  be  the  result.  We  think  a  patent  can 
be  obtained  on  the  device. 


NOVELTY  FAN. 

(165)  Sidney  Brown,  Lake  Charles,  La., 
has  submitted  a  design  of  a  certain  fan  in 
which  are  incorporated  novelty  lights.  Our 
advice  is  asked. 

A.  While  the  idea  seems  original  and 
while  a  patent  can  probably  be  obtained,  we 
think  that  the  resulting  flickering  of  the 
lights  will  be  a  serious  objection  unless  the 
device  is  to  be  used  only  for  advertising 
purposes,  such  as  window  display,  etc. 


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THE  ELECTRICAL  EXPERIMENTER 


July,  1917 


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EXPERIMENTAL  CHEMISTRY. 

{Continued  from  page  203) 
Sodium  Sulfate  [NaHSCX],  is  formed. 

If  two  molecules  of  the  salt  are  taken 
and  one  of  Sulfuric  acid,  a  less  soluble  salt, 
Normal  Sodium  Sulfate  [Na2S04]  is 
formed,  during  which  process  a  much 
higher  temperature  is  required. 

Hydrochloric  acid  can  also  be  formed  by 
the  union  of  its  constituent  elements, 
namely,  Hydrogen  and  Chlorin.  When  the 
gases,  Hydrogen  and  Chlorin,  are  brought 
together  in  the  dark,  no  action  takes  place. 
If  the  mixture  is  put  in  the  sunlight,  grad- 
ual combination  takes  place,  and  if  the 
direct  sunlight  is  allowed  to  fall  for  an 
instant,  an  explosion  occurs,  indicating  the 
combination  of  the  two  gases.  This  sud- 
den combination  is  also  effected  by  the 
application  of  a  flame,  by  a  spark  or  by 
any  intense  light,  as  magnesium  light,  etc. 

When  water  is  formed  by  the  combina- 
tion of  its  constituent  elements,  hydrogen 
and  oxygen,  the  introduction  of  an  electric 
spark  is  necessary.  This  combination 
[Hydrogen  and  Oxygen]  would  not  take 
place  upon  exposure  to  light.  Thus  we 
can  see  that  Hydrogen  and  Oxygen  can 
only  combine  to  form  water  by  introducing 
a  spark,  and  not  by  exposure  to  light,  while 
Hydrogen  and  Chlorin  unite  with  explo- 
sive violence  when  any  intense  light  is  per- 
mitted to  fall  directly  upon  the  mixture. 

Propertifs  : 

Physical:  1.  It  is  a  colorless  gas,  pos- 
sessing a  sharp  irritating  and  penetrating 
smell  and  taste,  and  produces  suffocation 
when  inhaled,  and  is  poisonous. 

2.  It  can  easily  be  liquefied  at  0°  and 
28  atmospheres,  and  solidifies  at  — 111.1°. 
In  the  liquefied  state  it  boils  at  — 83.7°. 

3.  It  is  very  easily  soluble  in  water. 

4.  It  is  a  little  heavier  than  air. 

5.  When  the  fumes  of  the  acid  come  in 
contact  with  moist  air,  dense  white  fumes 
are  formed,  and  due  to  the  great  attraction 
of  the  gas  for  water,  thus  condenses  the 
moisture.  The  fumes  when  the  acid  is 
brought  into  contact  with  Ammonia  gas, 
are  Ammonium  Chlorid  [NHjCl]. 

Commercial  Hydrochloric  acid  [Also 
called  Muriatic  acid]  generally  consists  of 
one-third  acid  to  two-thirds  water.  This 
liquid  if  pure,  should  be  without  color. 
Sometimes  it  is  of  a  yellow  color,  caused 
either  by  the  presence  of  dissolved  salts  of 
iron  or  organic  substances.  The  chemically 
pure  [C.  P.]  should  be  without  color.  This 
may  be  distilled  at  110°,  when  it  gives  a 
liquid  containing  20%  Hydrochloric  acid, 
and  corresponds  to  the  formula,  HC1  + 
8H^O.  If  more  Hydrochloric  acid  is  con- 
tained in  the  liquid,  heat  will  liberate  the 
gas ;  if  less,  water  will  be  liberated  upon 
the  application  of  heat. 
Chemical  : 

1.  Hydrochloric  acid  possesses  a  very 
strong  acid  reaction. 

2.  It  is  not  inflammable  [a  non-com- 
bustible gas],  and  does  not  support  com- 
bustion, and  is  not  decomposed  by  light  or 
on  heating;  but  its  hydrogen  may  be  re- 
placed by  metals  as  Zinc  or  Sodium,  and 
its  Chlorin  by  Manganese  dioxid  [MnO^]. 

3.  Sodium  or  Potassium  burns  vigor- 
ously in  it  on  heating,  forming  chlorids. 

4.  It  dissociates  into  its  elements  at 
1800°. 

5.  It  dissolves  most  metals,  forming 
chlorids. 

If  there  are  two  chlorids  of  a  given 


EXPERIMENTS 

FOR  EVERY  STUDENT 


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THE  ELECTRICAL  EXPERIMENTER 


221 


metal,  the  lower  is  usually  formed  by 
Hydrochloric  acid.  Silver  [Ar],  Lead 
[Pb],  Mercury  [Hg],  Copper  [Cu],  Plat- 
inum [Pt | ,  Gold  [An],  are  not  dissolved, 
or  are  very  slightly  acted  on  by  this  acid. 
Chlorids  of  the  first  three  are  insoluble ; 
chlorids  of  the  other  three  are  formed  by 
using  Aqua  Regia  [Hydrochloric  and  Nit- 
ric acids]. 

Uses  : 

1.  It  is  used  for  preparing  the  chlorids 
of  various  metals. 

As  stated  before,  Sodium  chlorid  is  the 
most  important  of  the  chlorids.  Common 
Salt  [Sodium  Chlorid |  besides  its  use  as  a 
preservative,  is  a  necessary  article  of  food 
with  all  animals  living  on  vegetable  diet. 
It  is  used  in  medicine,  internally,  in  small 
doses  as  a  gastric  stimulant,  in  large  doses 
as  an  emetic ;  externally  in  baths  for  the 
relief  of  rheumatism,  and  injected  in  solu- 
tion, to  replace  loss  of  blood. 

2.  It  is  used  for  extracting  phosphats 
from  bones. 

3.  It  is  used  in  dyeing  and  tissue  print- 
ing. 

4.  It  is  used  in  the  manufacture  of  coal- 
tar  colors. 

5.  It  is  used  in  preparing  other  com- 
pounds of  chlorin  than  chlorids,  and  in 
preparing  the  element  Chlorin  itself. 

6.  In  the  laboratory  it  is  used  for  gen- 
erating hydrogen,  also  in  analysis  and  in 
making  Aqua  Regia. 

7.  It  furnishes  chlorin,  from  which 
bleaching  powder  is  made. 

8.  The  silver  chlorid  [AgCl]  in  pho- 
tography is  deposited  upon  .  the  photo- 
graphic paper  from  solutions  of  Silver 
Nitrat  [AgN03]  and  Sodium  Chlorid 
[NaCl]. 

EXPERIMENT  NO.  73: 

Arrange  a  flask  [about  250  cc]  with  a 
two-hole  rubber  stopper  and  two  bottles, 
each  having  a  capacity  of  about  125  cc, 
make  connections  as  shown  in  Fig.  69. 
The  first  bottle  contains  a  three-hole  rub- 
ber stopper  thru  which  passes  the  delivery 
tube  from  the  generator  [the  flask  contain- 
ing the  Sodium  Chlorid  and  Sulfuric  acid ] , 
this  tube  should  extend  only  a  little  below 
the  stopper  in  both  the  flask  and  bottle,  and 
should  not  touch  the  solution.  A  long 
glass  tube  is  then  inserted  in  the  center 
hole  of  bottle  No.  1  above  the  cork  and 
below  the  surface  of  the  water.  This  is 
called  a  Safety  tube.  A  third  tube  just 
passes  thru  the  stopper  in  bottle  No.  1,  and 
leads  to  the  second  bottle  [which  does  not 
contain  a  cork]  and  in  which  the  delivery 
tube  is  permitted  to  be  under  the  water. 

A  Wolff  Bottle  (see  Fig.  70)  may  be 
used  in  place  of  No.  J,  and  if  this  form  is 
used,  one  containing  three  necks  is  to  be 
preferred. 

It  will  be  noticed  in  the  illustration  of 
the  apparatus  that  rubber  connectors  (cut 
diagonally — see  Fig.  73)  are  used  to  con- 
nect the  delivery  tubes  of  the  flask  and  sec- 
ond bottle.  If  it  is  desired,  the  tubing  may 
be  bent  in  one  piece  as  shown,  but  it  is 
more  convenient  to  use  separators,  as  the 
pieces  may  then  be  used  in  other  experi- 
ments. 

Fill  the  two  bottles,  1  and  2,  about  one- 
quarter  full  of  water.  Set  the  flask  on  a 
ring  stand  support,  on  a  piece  of  asbestos 
or  wire  gauze.  Pour  about  5  cc.  of  water 
into  the  flask  and  add  10  or  15  grams  of 
sodium  chlorid  [common  salt,  NaCl],  by 
pouring  into  the  flask  from  a  creased 
paper. 

Have  handy  a  splint,  also  an  evaporating 
dish  containing  three  or  four  drops  of 
Ammonium  Hydroxid  [NH,OH],  and  a 
stirring  rod  or  piece  of  paper. 

Make  sure  that  all  connections  are  air- 
tight,  then  pour  about  20  cc.  of  Sulfuric 


acid  fFLSOil  in  small  quantities,  say  three 
or  four  drops  at  a  time,  into  the  flask,  by 
means  of  a  thistle  tube.  Do  not  add  too 
much  acid  at  one  time. 

Action  will  probably  take  place  upon  the 
introduction  of  the  acid,  which  is  made 
apparent  by  the  bubbling  and  frothing  in 
the  flask,  but  to  aid  it,  a  Bunsen  flame 
should  be  placed  under  the  flask.  Do  not 
apply  too  much  heat,  and  if  the  liquid  tends 
to  pass  over  the  delivery  tube  into  the  first 
bottle,  remove  the  flame,  and  if  it  does  not 
abate,  add  a  little  water  thru  the  delivery 
tube. 

The  reactions  which  may  take  place,  are : 

1.  NaCl  +  H2SO.,    =      HCI  +  NaHSO, 

Sodium  Sulfuric  Hydrochloric  Hydrogen 
Chlorid         Acid  Acid        Sodium  Sulfate 


NaCl  +  2H2SQi 
Sodium  Sulfuric 
Chlorid  Acid 


:       2HC1       +  Na.SO, 
Hydrochloric  Sodium 
Acid  Sulfate 


The  equations  are  more  fully  explained  in 
the  preceding  methods  of  preparation. 

EXPERIMENT  NO.  74: 

Loosen  the  stopper  of  the  flask  and  very 
cautiously  try  the  odor  of  the  fumes.  Do 
not  inhale  too  much,  but  just  enough  to 
give  you  the  characteristic  smell.  [Note: — 
In  case  you  have  inhaled  an  overdose  of 
the  gas,  an  antidote  should  be  taken,  by 
inhaling  the  Ammonia  from  a  bottle  con- 
taining Ammonium  Hydroxid]. 

Apply  a  lighted  splint  to  the  open  mouth 
of  the  flask.  The  splint  should  go  out,  due 
to  the  fact  that  Hydrochloric  acid  gas  is  a 
non-supporter  of  combustion,  and  non-com- 
bustible. 

Either  bring  the  dish,  glass  rod  or  piece 
of  paper  dipt  in  the  Ammonium  Hydroxid 
to  the  mouth  of  the  flask.  Dense  white 
fumes  should  be  evolved  upon  the  intro- 
duction of  the  Ammonia  gas  [obtained 
from  the  Ammonium  Hydroxid]  coming  in 
contact  with  the  Hydrochloric  acid  gas. 
This  test  is  characteristic  of  the  gas. 

Look  very  closely  at  the  liquid  in  the 
bottles  1  and  2  while  the  action  is  taking 
place  in  the  flask.  If  you  look  thru  the 
bottle  at  a  strong  light,  it  will  be  noticed 
that  an  oily  liquid  is  being  precipitated  in 
these  bottles.  This  is  the  Hydrochloric  acid 
gas  which  is  forming  a  solution  with  the 
water. 

After  about  10  or  15  minutes  generating, 
remove  the  flame  from  under  the  flask. 
Allow  to  cool  for  a  few  minutes,  then  un- 
cork the  flask,  insert  a  funnel,  and  cau- 
tiously pour  in  two  or  three  test  tubes  full 
of  water.  The  flask  may  then  be  filled  from 
the  jet  and  the  contents  poured  out.  If 
the  substance  in  the  flask  has  caked,  be 
careful  not  to  break  the  glass,  but  let  it 
stand  till  cool  before  adding  the  water. 

Save  the  liquid  in  the  bottle  No.  1  for 
the  next  experiment. 

EXPERIMENT  NO.  75 : 

Pour  into  a  test  tube  about  5  cc.  of  the 
liquid  obtained  from  bottle  No.  1  in  the 
preceding  experiment,  and  into  a  second 
tube  pour  5  cc.  from  the  open  bottle;  then 
test  each  with  litmus  paper  or  solution. 
Determine  if  the  solution  is  an  acid  by  its 
action  on  litmus,  as  done  in  some  of  the 
experiments  already  performed. 

To  prove  what  is  present  we  must  apply 
tests  for  both  the  positive  and  the  nega- 
tive constituents  of  the  compound. 

EXPERIMENT  NO.  76: 

Pour  about  5  cc.  from  bottle  No.  1  into  a 
smajl  test  tube  and  add  two  or  three  pieces 
of  Zinc.  After  action  has  progrest  for  a 
short  time,  apply  a  lighted  splint  to  the 
mouth  of  the  tube  to  determine  if  a  gas 
escapes.  If  we  have  Hydrochloric  acid  in 
bottle  No.  1  it  is  reasonable  to  suppose  that 
Hydrogen  gas  will  be  liberated  when  Zinc 
is  treated  with  the  liquid. 


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THE  ELECTRICAL  EXPERIMENTER 


July,  1917 


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This  is  the  test  for  the  positive  con- 
stituent. 

EXPERIMENT  NO.  77: 

Pour  small  portions  from  bottle  No.  1 
into  three  tubes.  To  one  add  a  few  drops 
of  Lead  Nitrat  solution,  [Pb[N03]2],  to 
another  a  few  drops  of  Silver  Nitrat  solu- 
tion, [AgNOs],  to  the  third  a  few  of 
M  ercurous  Nitrat  solution  [HgN03]. 

White  precipitates,  the  chlorids  of  the 
metals,  Lead,  Silver  and  Mercury,  should 
form  upon  the  mixture  of  the  respective 
nitrats  with  Hydrochloric  acid. 

Soluble  Chlorids  : 

Soluble  chlorids  are  made  by  dissolving 
in  Hydrochloric  acid,  either  a  metal  or  some 
of  its  salts  which  are  transposed  by  it. 

Insoluble  Chlorids  : 

Insoluble  chlorids  may  be  made  by  adding 
Hydrochloric  acid  to  solutions  of  the  solu- 
ble salts  of  these  metals,  for  example,  Lead 
Nitrat  [Pb[N03],],  Silver  Nitrat  [AgNOs], 
Mercurous  Nitrat  [HgNOs].  There  are 
only  three  chlorids,  Lead  Chlorid  [PbCb], 
Silver  Chlorid  [AgCl],  Mercurous  Chlorid 
[HgCl]  insoluble  in  acidulated  water. 

Separations  : 

SupDose  we  were  to  mix  solutions  of 
Lead  Nitrat  [Pb[N03]2],  and  Copper  Nit- 
rat [Cu[NOs]a],  the  lead  could  be  sepa- 
rated from  the  copper  by  Hydrochloric 
acid,  for  the  former  would  precipitate  and 
the  latter  remain  in  solution.  On  filtering, 
the  lead  would  remain  on  the  filter  as  a 
residue  Lead  Chlorid  [PbCU],  and  the 
copper  would  pass  into  the  filtrat  un- 
changed as  Copper  Nitrat  [Cu[N03]2],  or 
Copper  Chlorid  [CuCU],  and  could  be  pre- 
cipitated by  Hydrogen  Sulfide  [H2S],  as 
Copper  Sulfide  [CuS].  A  mixture  of  Lead, 
Silver  and  Mercury  salts  could,  by  the 
same  reagent,  be  separated  from  other  salts 
in  solution.  This  is  exactly  what  is  done 
in  Analysis. 

EXPERIMENT  NO.  78: 

Mix  in  a  test  tube  about  5  cc.  of  Lead 
Nitrat  solution,  and  an  equal  amount  of 
Copper  Nitrat  solution.  From  the  above 
explanation,  see  if  you  can  devise  a  method 
of  separating  the  lead  from  the  copper  in 
the  solution. 

EXPERIMENT  NO.  79: 

Pour  about  20  cc.  of  Sulfuric  acid  [2  to  1] 
into  a  flask  supported  on  an  asbestos  mat 
on  a  ring-stand,  and  add  about  10  grams 
of  Sodium  chlorid  [Common  salt].  Gently 
rotate  the  flask  so  as  to  mix  the  acid  with 
the  chlorid.  Close  the  flask  with  a  two-hole 
stopper  carrying  a  thistle  tube  and  delivery 
tube  arranged  as  shown,  for  the  collection 
of  gas  by  downward  displacement  in  a  dry 
test  tube.  If  necessary  heat  the  flask  with 
a  small  flame.  The  contents  of  the  flask 
will  bubble  and  froth,  indicating  the  pro- 
cess of  liberating  the  gas  (Fig.  74). 

EXPERIMENT  NO.  80: 

Fill  a  dish  with  water  and  set  it  on  the 
table.  Take  a  test  tube  of  gas  collected 
[which  is  made  apparent  when  the  fumes 
are  liberated  in  the  air],  close  its  mouth 
tightly  with  the  thumb,  invert  the  test  tube, 
and  hold  its  mouth  below  the  surface  of 
the  water.  Remove  the  thumb.  Notice 
how  the  water  acts  with  the  gas. 

EXPERIMENT  NO.  81: 

Close  the  mouth  of  the  test  tube  with  the 
thumb  and  remove  it  from  the  water. 
Moisten  a  piece  of  litmus  paper  with  the 
liquid  contained  in  the  test  tube.  The  re- 
sult of  change  of  the  litmus  would  show 
that  this  effect  is  typical  of  the  water  solu- 
tion of  acids. 


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THE   ELECTRICAL  EXPERIMENTER 


223 


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August  issue  should  reach  us  not  later  than  June  25th. 

The  Classified  Columns  of  "The  Electrical  Experimenter"  Bring  Positive  Results. 
Subscribers  experiencing  trouble  in  dealing  with  any  advertiser  should  notify  the  publisher  very  promptly. 

OVER  75,000  PEOPLE  READ  THIS  JOURNAL 


WANTED— 1  K.W.  Marconi  or  United  Wire- 
less Transformer.  Harry  S.  Weber,  1113  N.  Wal- 
nut  St.,  Canal  Dover,  Ohio.  

FOR  SALE — >4  H.P.  gasoline  engine  in  excel- 
lent condition.  Price  $15.  Howard  Pfeiffer,  213 
Spring  Hill,  Connersville,  Ind. 

WANTED — Omnigraph;  must  be  in  first  class 
condition.  All  letters  answerod.  Archie  E.  Banks, 
Delmar,  Iowa.  

SACRIFICE — 4,000  Meter  Navy  Tvpe  Coupler, 
$6.50;  85  foot  Aerial,  $5;  Coil,  $2.75;  %  K.W. 
Gap,  50c;  Key,  50c.  Write  for  particulars. 
Howard  Nance,  Troy,  N.  C. 

BRAND  NEW — De  Forest  round  amplifier  or 
tubular  audion  bulb  $3.50  each.  First  money- 
order  takes  them.  R.  Cuthbert,  375  E.  184th  St., 
New  York. 

EXCHANGE  for  $14— One  Smith  Premier  No. 
4  typewriter,  excellent  condition,  used  only  short 
time.  Fred  Fries,  60  E.  Bringhurst  St.,  German- 
town,   Phila.,  Pa.  

WANTED — Stanley  Steam  Boiler  in  good  work- 
ing order.  Will  pay  cash.  Carl  Zeiner,  31  East 
Pleasant  St.,  Lawrence,  Mass.  

WANTED  FOR  CASH — Drummond  Bros. 
Model  Makers  Precision  Lathe.  Please  be  reason- 
able.    Write.     Frank  Coffman,  Silverton,  Oregon. 

MUST  SELL  AT  ONCE— Real  Bargains— All 
New:  Trans-Pacific  Receiving  Outfit  cost  $10, 
price  $8;  2,000  ohm  Phones  (Trans-Atlantic)  cost 
$6,  price  $4.80;  Crystaloi,  Type  AA,  cost  $6,  price 
$4.80;  Junior  Fixed  Condenser  40c;  "Electro" 
Loading  Coil,  $2;  "Turney"  Buzzer,  65c;  100  amp. 
600  volt  Switch  cost  $3.75,  price  $3;  "Electro''  Key 
25c;  9  Ball  Antenna  Insulators,  each,  20c;  8 
Electrose  Ball  Insulators,  each  20c;  Ground  Clamp, 
10c;  200  ft.  Suspension  Rope,  50c  per  100  ft.;  2 
Aerial  Pulleys,  each  5c;  one  3  volt  Nitrogen 
Battery,  30c;  two  "Electro"  Dry  Batteries,  each 
20c;  y2  lb.  Friction  Tape,  20c;  "Electro"  Solder- 
ing Outfit,  25c;  Fusible  Cut-outs,  3  fuses,  15c; 
Electrose  Lead-in,  cost  $1.30,  price  $1;  5  pr. 
porcelain  cleats,  10c;  Large  Mineral  Assortment, 
95c;  V<  oz.  Alloy,  10c;  Blue  Book,  10c;  "Electro'' 
Thriller  and  Magneto,  70c;  Book  "Experimental 
Wireless  Stations,"  $1.00;  200  ft.  aerial  copper 
cable,  50c  per  100  ft.;  900  ft.  No.  16  Antenium 
copper  wire,  30c  per  100  ft.;  20  ft.  No.  4  copper 
ground  wire,  80c.  Purchaser  to  pay  charges  on 
orders  less  than  $5.  All  above  brand  new. 
Address,  Fred  Allen,  Vernon,  Alabama. 

FOR' SALE  OR  EXCHANGE— Electrical  Thera- 
peutic  Apparatus  new  and  in  good  condition;  all 
equipments.  Medical  remedy  for  rheumatism,  bad 
circulation  or  any  stagnetic  element.  First  good 
offer  takes  it.  John  Ferguson,  113  West  63rd  St., 
New  York  City,  home  address,  364  West  57th  St. 

GENERAL  ELECTRIC  D.  C.  Ammeter  $12.50. 
Six  Edison  primary  batteries,  $8.  60  numbers 
Popular  Mechanics,  $7.50.  Type  BB  Crystaloi 
and  resonance  coil,  $10.  Want  Colts  .32  automa- 
tic pistol  and  25-20,  32-20  or  .22  Winchester 
repeating   rifles.     Coyd   Maffet,   Opal,  Colorado. 

STOP!  LOOK!  First  $8  gets  4  H.P.  motor- 
cyclc  engine,  in  fine  condition,  with  tanks,  piping, 
plug.  Write  for  particulars.  Earl  Wright,  Cole 
Camp,  Mo. 

FOR  SALE — Audion  Detector  complete  with 
two  bulbs;  y2  K.W.  Transmitting  Set;  Undamped 
coupler;  Navy  coupler;  Phones;  Aerial  Wire; 
Interrupter;  Crystal  Detectors.  All  in  good  work- 
ing order.  Louis  E.  Krieg,  Tr.,  134  No.  School 
St.,  Gloversville,  N.  Y.  

WANTED— Burnt-out  De  Forest  Audion  bulbs. 
Will  pay  $1.50  if  bulbs  are  not  broken.  Harold 
Schonwald,  443   E.  Padon,  Blackwell.  Okla.  

FOR  SALE — iy2"  spark  coil  and  electrolytic  in- 
terrupter in  good  condition.  Make  an  offer. 
T.  R.  Wiley,  Piqua,  Ohio.  

FOR  SALE — Electrical  and  wireless  apparatus, 
a  small  mechanical  drawing  set,  a  ten  mile  Pedom- 
eter. _  Send  stamp  for  list  of  other  apparatus. 
Francis  T.  Crump,  Jr.,  Columbus,  Ind.  

FOR  SALE  OR  EXCHANGE— 4  H.P.  motor- 
cycle engine  $15  for  bicycle,  rifle  or  what?  M.  J. 
Liese,  511  S.  Morgan  St.,  Chicago,  111. 


FOR  SALE — AudioTron  panel  complete  with 
new  bulb  and  battery,  $7;  Mesco  2"  spark  coil, 
$6;  Murdock  oscillation  transformer,  $3.  Send 
for  big  list.  Want  omnigraph.  Thomas  Kelly, 
1614  S.  54th  St.,  Philadelphia,  Pa.  

WANTED — Second-hand  drafting  instruments. 
Highest  prices  paid.  Send  complete  description 
and  we  will  make  offer.  Deutsch,  2358  Pitkin 
Ave.,  Brooklyn,  N.  Y.  

SACRIFICE:  BARGAINS— 3,000  Meter  Navy 
Tvpe  Coupler,  $6.50;  Murdock's  2,000  ohm  Phones, 
$3';  V?"  Coil,  $1.75;  Complete  100  foot  Aerial,  $5; 
Lead-in  Insulator,  50o;  Knapp  Motor,  $1.25;  Key, 
50c;  Gap,  50c;  Transformer,  $2.  Write  Bernard 
Brown,  Troy,  N.  C. 

iUllllllllllllllilllllllllli 

I    TALK  ABOUT  RESULTS!  | 

|  17  PRYER  LANE, 

■  Larchmont  Manor,  N.  Y.  | 

=     The  Experimenter  Pub.  Co. 
New  York  City 

■  Dear  Sir: — 

Talk  about  results!  You've  || 

■  got  to  give  it  to  the  "E.  E."  J 

■  to  reach  the  right  people.  On  ■ 

■  the  day  after  "E.  E."  came  ( 
H  out  I  received  a  reply  and  S 
(  they  have  been  coming  in  at 

■  the  rate  of  one  a  day.    If  I  J 
H  ever  have  anything  else  that  j 
[  I  want  to  sell  I  will  send  my  [ 
1  "ad"  to  you  every  time. 

.  Yours  truly, 

m  Clarence  de  Witt  Rogers,  Jr.  g 

■IIIIIIIIIIIIIIIIIIIIIH 

CHEAP— Smith  Motor  Wheel,  $35.  1  H.P. 
Redemotor,  $8.  Both  excellent  condition  Will 
trade.   Enclose  stamp.    Earl  Roske,  Columbus,  Wis. 

FOR  SALE  OR  EXCHANGE— Ford  spark  coil, 
$1;  telephone  transmitter,  50c;  telephone  magneto, 
75c. _  Write  for  list.  What  have  you?  Sidney 
Collisson.  Keokuk,  Iowa.  

FOR  SALE— Brief-hand  Manual,  35c;  $7.50  de- 
tective course,  $1.50;  $10  finger  print  course,  $1; 
$5  hypnotism  course,  $1.  Prepaid;  back  numbers 
E.E.;  M.E.;  A.B. ;  farm  papers  and  others;  elec- 
trical  and  wireless   instruments.     W.   B.  Bagley, 

Stirling  City,  Cal.  

K.W.  Transformer  coil  and  electrolytic 
interrupter  in  fine  condition,  first  money  order  for 
$6  takes  both.  Walter  Alexander,  Dunkerton, 
Iowa. 

FOR  SALE  OR  EXCHANGE— A  Frank  Holton 
Cornet,  with  case,  costs  $50  when  new.  Every- 
thing in  excellent  condition.  The  first  good  offer 
takes  it.     Veryl  Ebert,  Alden,  Minn. 

STOP!  LOOK!  SACRIFICE!— -J4"  Spark  Coil, 
$1.25;  Wheatstone's  Bridge,  $3;  Large  Voltam- 
meter,  $3;  all  rest  E.  I.  Co.  goods:  $1  Key,  60c; 
Fixed  Variable  Condenser,  75c;  3,  15  Ampere 
D.P.D.T.  Switches,  20c  each;  Ammeter,  40c; 
Hustler  Motor,  40c;  Receivers,  1000  ohm  D.P., 
$1;_  2,  75  ohm  D.P.,  $1;  2,  75  ohm  S.P.,  60c. 
Satisfaction  guaranteed.  C.  Krummenacker,  1034 
73  St.,  Brooklyn,  N.  Y. 


WANT — 110  A.  C.  Voltmeter  and  Ammeter, 
cash  or  exchange.  Have  wireless  and  electrical 
goods.  What  do  you  want?  C.  H.  Rauschenberg, 
Charleroi,  Pa.  

WANTED  FOR  CASH  or  exchange.  Alternat- 
ing  current  motor  J^-J/j  H.P.  110  volts  60  cycles. 
Have  1/12  H.P.  variable  speed  motor.  Also  want 
lathe,  Drummond  preferred.  Carroll  Pfleegor, 
Milton,  Pa.  

BARGAIN — Smith  Premier  typewriter  for  sale. 
Cost  new  $100,  will  take  $25.  Little  used.  Money 
order  or  certified  check  accepted.  S.  W.  Dearing, 
Covington,  Tenn.,  Route  2.  

EXCHANGE  OR  SELL  110  volt  Alternating 
Current  %  Horsepower  Westinghouse  Motor. 
What  will  you  give?  Frank  V.  Golitz,  Box  194, 
Patton,  Pa.  

EXCHANGE — A  wireless  set,  3,000  M.  coupler 
and  an  AudioTron.  Want  an  F6:3  Kodak.  H. 
Parker,  212  Park  Ave.,  Syracuse,  N.  Y. 

FOR  SALE  OR  EXCHANGE— Album  and  over 
500  stamps.  Make  offer.  I  want  Leyden  Jar. 
Jesse  Burton,  Culpeper,  Va. 

FOR  SALE — Four  cylinder  10  horsepower  2 
speed  Pierce  motorcycle,  Al  conditon,  fully 
equipped,  magnetp,  rear  seat,  practically  brand 
new  tires,  for  quick  sale  $85.  Twelve  inch  Gen- 
eral Electric  fan,  110  A.  C.  Good  shape  but  old 
model,  $3.  Stevens  Favorite  22  cal.  rifle  $3. 
Winchester  22  Automatic  $12.  Both  in  perfect 
condition."  Blickensderfer  typewriter,  brand  new, 
tools,  etc.,  $10.  Complete  100  mile  sending  and 
receiving  set,  first  class  shape  $18.  Money  orders 
or  certified  checks.  Stephen  H.  Porter,  124 
Annetta  St.,  Syracuse,  N.  Y. 

SACRIFICE— For  cash,  $125  Siemens-Holske 
Galvanometer.  Extremely  sensitive  and  compact. 
Dead  beat.  New.  Foreign  2,000  ohm  polarized 
relay.  Scientific  rheostat.  Don  MacDonald,  215 
W.  23rd  St.,  New  York  City.  

FOR  SALE — 2,500  mile  receiving  set,  complete 
with  aerial,  fixtures,  never  been  used.  $20  for 
outfit.     John  Wells,  Ada,  Ohio.  

FOR  SALE— Dvnamo,  $4.f0;  1,800  M.  Coupler, 
$4.50;  Loading  Coil,  $1;  H  inch.  Spark  Coil,  $1.25; 
Storage  Cell,  $1.50;  Erector  Motor,  70c;  Weeden 
Motor,  75c;  Erector  Electrical  Set.  Postage  extra. 
Frank  Fletcher,  Warner  St.,  Hudson,  Mass. 

SEN  DING-RECEIVING  new"  and  complete, 
$5.50.  Books,  Rotary  Printing  Presses,  Simplex 
Typewriter,  "Modelit"  outfit.  Want  Cash.  Fold- 
ing Brownie.  Other  bargains  for  stamp.  Field, 
South  Weymouth,  Mass. 

SELL — Twelve  Horsepower  two  cylinder  auto- 
mobile gasoline  engine  complete  with  carburetor 
and  high  tension  magneto,  $25.  Splitdorf  and 
Remy  magneto's  with  coils.  $7.50  li  Horsepower 
Vertical  Steam  Engine  with  boiler,  $6.  14  Horse- 
power Horizontal  Steam  Engine  with  boiler,  $11. 
Clarence    Vaughan,    Middletown,    N.  Y. 

FOR  SALE — International  Correspondence 
Schools'  complete  Electric  Lighting  and  Railway 
Course.  Five  leather  volumes,  finest  condition. 
Best  offer  takes  them.  Reason  for  selling,  have 
more  comprehensive  course.  Paul  Mackey,  619 
Shakespeare  Ave.,  Milton,  Pa. 

FOR  SALE— Good  32  caliber  Revolver,  $4. 
Also  two  Battery  Motors,  $1  each.  Earl  Cook, 
Bernardston,  Mass. 

FOR  SALE — I.  C.  S.  course  in  chemistry, 
chemistry  and  technology.  For  Exchange  storage 
battery,  dynamo,  wireless  instruments,  etc.,  for 
Smith  Motor  wheel.  Leo  E.  Edmonds,  125  U  St., 
N.  E.,  Washington,  D.  C.  

FOR  SALE — Receiving  outfit,  Lionel  train,  2A 
and  00  Brownies.  Stamp  for  photo.  A.  L.  H. 
Darragh,   Beaver,  Pa.  

SALE  OR  EXCHANGE— Two  wireless  receiv- 
ing  sets;  damped  and  undamped  waves;  never 
been  used.  Small  transmitting  set.  M.  Guyton, 
Cotton  Plant.  Miss.  

FOR  SALE— Duck's  5AA  Receiving  Transform- 
er, $15;  Type  "O"  Crystaloi,  $3.10;  Turney  Buz- 
zer, 90c.  All  new,  never  used.  High  grade  4x5 
Folding  Camera,  uses  films  or  plates,  automatic 
8  speed  shutter,  carrying  case,  etc.,  $15.  J.  Frank 
Key,  Buena  Vista,  Va. 


You  benefit  by  mentioning  "The  Electrical  Experimenter"  when  writing  to  advertisers. 


224 


THE  ELECTRICAL  EXPERIMENTER 


July,  1917 


"2" 


Opportunity  Exchange 


X/OU  will  probably  find  more  opportunities  and  real  bargains  in  these  columns  than  anywhere  else  in  the  country.  Most  good  things  in 
A  life  are  hard  to  find  and  worth  going  after — these  little  ads  illustrate  that  point;  you  alone  will  be  the  real  loser  if  you  don't  take  the 
time  to  scan  through  these  columns. 

Advertisements  in  this  section  4c.  a  word  for  each  insertion.     Count  7  words  per  line. 

Name  and  address  must  be  included  at  the  above  rate.  Cash  should  accompany  all  classified  advertisements  unless  placed  by  art  accredited 
advertising  agency. 

Ten  per  cent,  discount  for  6  issues,  20  per  cent,  discount  for  12    issues  from  above  rate.    Objectionable  or  misleading  advertisements  not 

accepted. 

Advertisements  for  the  August  issue  should  reach  us  not  later  than  June  25. 

OVER  75,000  PEOPLE  READ  THIS  JOURNAL 

EXPERIMENTER  PUBLISHING  CO.,  INC.,  233  Fulton  Street,  New  York,  X  Y. 


4 


AERONAUTICS 


AERIAL  AGE,  America's  only  illustrated 
weekly,  presents  the  latest  developments  in  aero- 
nautics throughout  the  world.  Up  to  the  minute 
technical  information  concerning  aero-engines, 
aeroplanes,  accessories  and  patents.  Complete 
model  news  and  instruction.  Trial  subscription 
six  months,  twenty-six  issues,  One  Dollar.  Sample 
copy  free.  Aerial  Age,  280  Madison  Ave.,  New 
York  Citv,  New  York. 


BOOKS 


TO  GET  BETTER  PICTURES:  Read  the 
Amateur  Photographer's  Weekly;  illustrated; 
weekly  prize  competitions;  print  criticisms;  many 
unique  features;  $1.50  per  year;  three  months  trial 
subscription,  25c.  Abel  Publishing  Company,  401 
Caxton   Bldg.,   Cleveland,  Ohio. 

BOOKS — Scientific  and  wireless  supplied.  Let 
us  know  what  vou  want  and  we  will  quote  you. 
Experimenter  Pub.  Co.,  233  Fulton  St.,  New  York 
City.  ____ 

A  BINDER  for  THE  ELECTRICAL  EXPERI- 
MENTER will  preserve  your  copies  for  all  time. 
Price  50c.  Postage  on  3  lbs.  is  extra.  Send  for 
one  today.  Experimenter  Pub.  Co.,  233  Fulton 
St.,  New  York  City.  

DO  YOU  WANT  back  numbers  of  THE  ELEC- 
TRICAL EXPERIMENTER?  Send  for  bound 
volume  No.  3  containing  issues  from  May,  1915 
to  April,  1916.  Price,  $1.25.  Postage  on  7  lbs. 
is  extra.  Experimenter  Pub.  Co.,  233  Fulton  St., 
New  York  City. 

WE  HAVE  a  limited  number  of  beautiful  art 
pictures  of  the  following  famous  electrical  men  on 
hand.  Nikola  Tesla,  Thomas  A.  Edison,  GugHelmo 
Marconi,  Charles  P.  Steinmetz,  and  Reginald  A. 
Fessenden.  These  make  a  handsome  decoration  for 
any  laboratory  or  workshop  and  should  be  prom- 
inently displayed.  Price  for  five,  prepaid,  25c. 
Experimenter  Pub.  Co.,  233  Fulton  St.  New  York 
City.  

OLD  E.E.  BACK  NUMBERS — We  have  some 
valuable  old  E.E.  back  numbers  on  hand  as  per 
list  below. 


1915 

March  .  .price  each  $.20 

Jan.  .  . 

.price  each  $.25    April    ..."        "  " 

Feb.  .  . . 

.    "        "       "      May    " 

March  . 

"        "       "      June      .  .    ''        "  " 

April    .  . 

.    "        "       "      July  ..." 

May  .  .  . 

.    "        "       "      August    .  " 

June 

.    "       "      "      Sept.  ..." 

July  .. 

.    "       "      "      Oct   " 

August 

.    "       "      "      Nov   " 

Sept.  . 

.    "       "      "      Dec   " 

Oct.   .  . . 

"       «      "  1917 

Nov.  . 

.    "        "       "      Jan              "        "  .15 

Dec.  .  . 

.    "       "      *'      Feb   " 

1916 

March  . .    "       "  " 

Jan.    .  . 

.    "       "      .20    April  ..." 

Feb.   .  . 

.    "       "      "      May  .  .  .  .    "       "  " 

We  can  fill  orders  at  once  upon  receipt  of  your 
remittance  and  if  you  have  not  these  numbers  al-. 
ready  now  is  your  chance  to  get  them  as  they  prob- 
ably will  be  snapped  up  very  quickly.  Experi- 
menter Publishing  Co.,  233  Fulton  St.,  New  York 
City.  

FIRE  SALE  OF  SLIGHTLY  DAMAGED 
BOOKS.  Due  to  fire  in  our  stock  rooms,  a  great 
many  of  our  books  were  water  stained  but  not  other- 
wise damaged.  Rather  than  dispose  of  them  to 
dealers  we  prefer  to  give  our  readers  the  benefit. 
Look  at  this  list!  Our  Celebrated  Wireless  Course, 
160  pages,  400  illustrations;  List  of  Radio  Stations 
of  the  World;  Experimental  Electricity  Course, 
160  pages,  350  illustrations;  How  to  Make  Wireless 
Sending  Instruments.  These  four  books  for  $1.50 
prepaid.  Regular  selling  price  of  these  four  books 
is  $2.75.  We  guarantee  you  will  be  satisfied.  Ex- 
perimenter Pub.  Co.,  233  Fulton  St.,  New  York 
Citv. 


CHEMICALS 


CHEMICALS  FREE  for  growing  chemical  plants. 
To  introduce  our  chemicals  and  apparatus  to  Ex- 
perimenters, we  will  send  free,  the  necessary 
chemicals  to  grow  trees,  grass,  etc.  Send  10c 
coin  (refunded  on  first  order)  for  postage  and 
catalog.  Zenith  Chemical  Laboratories,  307  West 
Second  St.,  Duluth,  Minn. 


HELP  WANTED 


WAR  MEANS  THOUSANDS  Men-Women,  18 
or  over,  wanted  by  Government  for  excellent 
clerical  positions,  $100  month.  Steady  work.  Short 
hours.  Life  appointment.  Common  education 
sufficient.  Write  immediately  for  free  list  of 
positions  now  obtainable.  Franklin  Institute. 
Dept.  D27,  Rochester,  N.  Y. 


MISCELLANEOUS 


BOYS!  LOOK!— Send  one  dime  for  the  Letter 
"H"  Puzzle,  the  hardest  on  the  market  to  solve. 
Or  the  "Phantom  Trick  Cards."  The  greatest 
card  trick  ever  invented.  Chas.  H.  Derr,  306  N. 
9th  St.,  Allentown,  Pa. 

DECALCOMANIE  Initials  for  monograming 
automobiles,  etc.  Wholesale  price  list  and  samples 
free.  A  set  of  Old  English  letters  and  material 
for  quickly  applying  $1.00  postpaid.  Globe  Decal- 
comanie  Co.,  Mfgs.,  Jersey  City,  N.  J. 

FORMULAS— We  will  send  you  the  Formula 
for  anything  you  want  to  know  for  10c  (coin). 
National  Exchange,  1314  Park  Ave.,  New  York. 

STAMPS  —  75,  all  different,  free.  Postage,  2c. 
Mention  paper.     Quaker  Stamp  Co.,  Toledo,  Ohio. 


151  LAKE  AYE., 

Lancaster,   N.   Y.  |g 

Feb.  22,  1917.  S 

Gentlemen :  g 
I  wish  to  tell  you  that  my  ad.  in  {S 
the  E.  E.  was  a  great  success,  and  S; 
exceeded  all  expectations.  I  had  re-  M 
plies  before  I  had  received  a  copy  of  H 
the  issue  myself.  This  goes  to  show  g 
that  every  issue  is  looked  for  with  W 
great  interest,  and  the  wide  field  vour  g 
paper  covers.  I  certainly  will  recom-  g 
mend  it  to  the  amateurs  that  have  m 
something  to  trade  or  sell. 

Yours  respectfully, 

G.  W.  Bradfopd.  H 


PATENT  ATTORNEYS 


PATENTS  ON  EASY  PAYMENTS.  Send 
model  or  sketch  for  Free  Search  and  Certified 
Registration  of  Your  Invention  for  Your  Protec- 
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AUGUST,  1917 


15  CENTS 


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ELECTRICAL    NEWS  ILLUSTRATED 


BLINDING  THE 
SUBMARINE 

5 EE  PAGE  234 


LARGEST  CIRCULATION  OF  ANY  ELECTRICAL  PUBLICATION 


This  is  the  Electrical  Age,  and  this  wonderful  new  profession  is  calling-  you.  The 
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CHICAGO  ENGINEERING  WORKS 

Dept.  38      ::       439  CASS  STREET,  CHICAGO,  ILL. 


Yo:t  benefit  by  mentioning  "The  Electrical  Experimenter"  when  writing  to  advertisers. 


August,  1917 


THE  ELECTRICAL  EXPERIMENTER 


225 


FELDMAN'S  "GEYSER"  ELECTRIC  WATER  HEATER 


Continuous  Flow  of  Water 
as  Desired.    Always  Ready. 

You  only  pay  for  electricity  as  used. 
All  water  that  passes  through  the 
"Geyser"  is  thoroughly  sterilized. 
The  "Geyser"  is  perfectly  insulated 
and  is  absolutely  safe,  no  danger  of 
short  circuiting  or  electric  shock. 

Cold  to  Hot  Water  by  Merely 
Turning  Handle. 

Both  the  water  and  the  current  act 
together  and  both  controlled  by  the 
movement  of  the  faucet  handle.  To 
secure  hot  water  turn  handle  to  the 
left,  for  cold  water  turn  to  the  right, 
at  the  center  both  the  water  and  cur- 
rent are  shut  off. 

The  Supreme  Court  has  decided  that  we 
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Others  take  warning,  as  we  zuill  prosecute 
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226 


THE  ELECTRICAL  EXPERIMENTER 


August,  1917 


Bead  ikivI'miaihaMe  ©ffei'J 


This  masterpiece  contains  160  pages,  400  illustrations.  Size 
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^Electrical 
jS  Experimenter  S| 


This  is  a  very  limited  offer.  It  may  be  withdrawn  at  any  time,  due  to  the 
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the  above  books.  If  you  subscribe  for  two  years,  BOTH  BOOKS 
WILL  BE  GIVEN  FREE,  POSTPAID. 


Gentlemen: 


I  f  you  are  a  subscriber  at  present,  take  advantage  of  this 
wonderful  opportunity  anyway.  If  you  do,  we  will  extend 
your  present  subscription  for  one  year. 


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The  Electrical  Experimenter 

233  FULTON  STREET,  NEW  YORK 

Piiblisht  by  Experimenter  Publishing  Company,  Inc.  (H.  Gernsback,  President;  S.  Gernsback,  Treasurer;)  233  Fulton  Street,  New  York 

Vol.  V    Whole  No.  52  AUGUST,  1917  No.  4 


BLINDING  THE  SUBMARINE  Front  Cover 

From  a  painting  by  George  Wall 

TESLA'S  VIEWS  ON  ELECTRICITY  AND  THE  WAR  

By  H.  Winfield  Secor  229 

ELECTRIC  SUBMARINE  FORTS  TO  DESTROY  SUBMARINES.  231 

PUTTING  THE  OCEAN  WAVES  TO  WORK.  .Bv  Charles  W.  Geiger  232 

BLINDING  THE  SUBMARINE  ."..By  H.  Gernsback  234 

THUNDER-STORMS  AND  LIGHTNING  RODS  By  Terrel  Croft  236 

WOMEN  RADIO  OPERATORS  TO  AID  UNCLE  SAM   238 

AN  ELECTRICAL  MINIATURE  VILLAGE  DE  LUXE   240 

LET  THE  ELECTRIC  REFRIGERATOR  KEEP  YOUR  FOOD   242 

UNIQUE  ELECTRICAL  APPARATUS  READS  THE  MIND   245 

THE  RADIO  BOMB— A  WIRELESS  STORY  By  C.  M.  Adams  246 

DIONIC  WATER  TESTER  OPERATES  BY  ELECTRICITY   248 

'-"PERPETUAL  MOTION"— A  CHANCE  TO  BECOME  FAMOUS..  243 

EXPERIMENTAL  PHYSICS— LESSON  6  

By  John  J.  Furia,  A.B.,  M.A.  250 


RADIO  LEAGUE  OF  AMERICA   NEWS   251 

THE  AMATEUR  AND  EXPERIMENTAL  RADIO  RESEARCH.... 

By  Raymond  Francis  Yates  254 
DETAILS  OF  A  20,000  METER  UNDAMPED  RADIO  RECEIVER. 

By  Wm.  Burnett,  Jr.  258 

"BATS"— A  DISCOURSE  ON  SOME  FREAK  BATTERIES  

By  Thomas  Reed  261 
AN  ELECTROLYTIC  INTERRUPTER  FOR  LOW  VOLTAGES.... 

By  C.  A.  Oldroyd  263 

A  HAND-FEED  ARC  FOR  THE  EXPERIMENTER  

By  James  Pratt  264 

"HOW-TO-MAKE-IT  DEPT."  PRIZE  CONTEST   266 

EXPERIMENTAL  CHEMISTRY— FIFTEENTH  LESSON  

By  Albert  W.  Wilsdon  267 
WRINKLES,  RECIPES  AND  FORMULAS.  .Edited  by  S.  Gernsback  268 
"WITH  THE  AMATEURS"  DEPT.  (SPECIAL  CASH  PRIZES)..  269 
QUESTION  BOX    271 


The  Submarine  War  \V 


m 


in 


(HERE  is  hardly  a  problem  today  of  greater 
importance  and  of  a  greater  complexity 
than  the  submarine  warfare.  It  affects  not 
only  this  nation,  but  every  nation,  big  and 
little,  over  the  entire  globe. 

So  complex  and  so  entirely  new  is  this 
problem  that  it  paralyzes  clear  thinking  of 
expert  and  layman  alike.  Logic  runs  rampant,  even 
great  thinkers  and  scientists  continuously  clashing  in 
their  widely  divergent  opinions.  There  is  a  chaos  of 
plans,  suggestions,  inventions  and  schemes  that  seem  to 
stupefy  everyone  concerned  in  solving  the  problem. 
And  there  seems  to  be  no  ray  of  light  in  all  the  darkness 
so  far. 

A  visitor  from  Mars,  not  affected  by  the  war  fever 
bacillus,  which  now  infects  the  whole  world,  would 
surely  look  in  amazement  upon  the  strange  spectacle 
now  being  enacted  upon  this  planet. 

He  would  marvel  first,  that  during  the  three  years  of 
submarine  warfare,  no  general  plan  to  combat  the  dan- 
ger had  been  evolved  by  the  several  Allies.  Everyone 
seems  to  be  trying  something  different  from  somebody 
else,  but  there  is  no  cohesion,  no  general  cooperation 
that  he  could  perceive. 

Our  Martian  friend,  after  having  looked  on  a  while 
would  probably  say:  "With  the  scientific  knowledge  now 
at  your  command,  there  are  only  a  few  ways  to  success- 
fully combat  the  submarine  evil.  Either  one  will  do  per- 
fectly, choose  the  one  which  is  best  adapted  to  your 
present  day  technique.  Broadly  speaking,  there  are  only 
three  practical  means  of  effectively  dealing  with  the 
submarine.    They  are : 

"1st.    Destroy  the  submarine. 

"2nd.  Prevent  the  torpedo 'from  reaching  the  attacked 
ship. 

"3rd.  Blind  the  submarine  so  it  can  not  take  the  ship's 
bearings." 

There  are,  of  course,  more  means  than  these  three, 
but  they  can  be  left  out  on  account  of  being  impractical. 
Also  each  one  of  the  above  classes  can  be  subdivided 
into  numerous  other  classes  ;  thus  the  suggestion  to  find  a 
means  of  preventing  the  submarine  from  leaving  its 
harbor  comes  really  under  class  2  because  the  primary 
purpose  of  a  submarine  is  to  sink  ships  with  a  torpedo. 


Gunfire  from  the  U-boat  is  aksegpnd££\  c6*ns|]leration, 
for  with  ships  becoming  arram  ^c^rr\rA.  more,  the 
submarine  is  forced  to  rely  upon^sQbrpeaqej/ 

At  the  present  time  our  inventoVs<are  wdtsting  valu- 
able time  trying  to  invent  submarine^^cfetectors."  Of 
what  earthly  use  are  these?  Suppose  we  do  know  that 
a  submarine  is  near  our  ships?  Suppose  that  we  even 
know  its  exact  position?  What  will  it  help  us?  Our 
knowledge  will  certainly  not  prevent  a  torpedo  from 
reaching  our  ship.  You  can't  destroy  a  submerged  U- 
boat  as  yet.  Even  running  in  a  zig-zag  line  does  not 
always  help,  for  the  crafty  U-boat  commander,  if  he 
can  but  take  a  few  observations,  running  in  a  straight 
line  behind  the  fleeing  ship,  will  average  the  zig-zag 
course  and  if  he  wants  to  use  two  torpedoes,  one  of 
these  almost  certainly  will  find  its  mark. 

While  in  some  high  quarters  the  opinion  prevails  that 
there  will  never  be  found  a  real  cure  against  the  sub- 
marine evil,  we  refuse  to  share  such  a  view.  There 
has  never  been  a  weapon  in  all  history  which  in  time  did 
not  find  its  equal  or  its  master.  The  submarine  and  its 
torpedo  will  prove  no  exception  to  this  rule.  Science 
in  the  end  will  conquer  as  it  always  does. 

It  is  more  than  probable  that  it  will  not  be  a  startling 
new  invention  that  will  solve  the  problem.  Rather,  we 
venture  the  opinion  that  a  combination  of  well  known 
and  tried  out  methods  will  do  the  trick.  All  indications 
point  that  way.  Also,  we  believe  that  either  means  2  or 
3  as  above  enumerated  will  prove  the  simpler  of  the 
three. 

If  we  would  only  make  up  our  minds  which  course 
to  pursue,  the  solution  of  the  problem  would  be  reached 
much  sooner. 

It  is  foolish  and  humiliating  trying  to  build  ships 
faster  than  the  U-boats  can  sink  them.  If  we  pursue 
this  course  the  U-boat  will  win  in  the  end.  If  the  sun 
melts  your  ice  too  fast  you  don't  go  and  put  out  more  ice 
in  the  sun.  You  devise  means  to  keep  the  sun  away 
from  the  ice,  by  protecting  the  latter. 

The  submarine  war  is  no  different.  And  we  will  need 
a  lot  of  ships.  Let  our  inventors  devise  means  to  pro- 
tect them  adequately. 

H.  Gernsback. 


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THE  ELECTRICAL 
EXPERIMENTER 


H.  GERN5B&CK  editdr 

H.  W.  A55DZ\UTE  EDITOR 


Vol.  V.   Whole  No.  52 


August,  1917 


Number  4 


Tesla's  Views  on  Electricity  and  the  War 


By  H.  WINFIELD  SECOR 
Exclusive  Interview  to  THE  ELECTRICAL  EXPERIMENTER 


NIKOLA  TESLA,  one  of  the 
greatest  of  living  electrical  engi- 
neers and  recipient  of  the  seventh 
"Edison"  medal,  has  evolved  sev- 
eral unique  and  far-reaching  ideas 
which  if  developed  and  practically  applied 
should  help  to  partially,  if  not  totally,  solve 


interview  and  some  of  his  ideas  on  elec- 
tricity's possible  role  in  helping  to  end  the 
great  world-war  are  herein  given: 

The  all-absorbing  topic  of  daily  con- 
versation at  the  present  time  is  of  course 
the  "U-boat."  Therefore,  I  made  that  sub- 
ject my  opening  shot. 


pacity  of  chief  electrician  for  an  electric 
plant  situated  on  the  river  Seine,  in  France, 
I  had  occasion  to  require  for  certain  test- 
ing purposes  an  extremely  sensitive  gal- 
vanometer. In  those  days  the  quartz  fiber 
was  an  unknown  quantity — and  I,  by  be- 
coming specially  adept,  managed  to  pro- 


ENEMY  SUBMARINE 


Nikola  Tesla,  the  Famous  Electric  Inventor,  Has  Proposed  Three   Different   Electrical   Schemes  for    Locating   Submerged  Submarines. 
The  Reflected  Electric  Ray  Method  Is  Illustrated  Above;  the  High-Frequency  Invisible  Electric  Ray,  When   Reflected  by  a  Submarine 
Hull,  Causes  Phosphorescent  Screens  on  Another  or  Even  the  Same  Ship  to  Glow,  Giving  Warning  That  the  U-boats  Are  Near. 


the  much  discust  submarine  menace  and  to 
provide  a  means  whereby  the  enemy's  pow- 
der and  shell  magazines  may  be  exploded 
at  a  distance  of  several  miles. 

There  have  been  numerous  stories 
bruited  about  by  more  or  less  irresponsi- 
ble self-styled  experts  that  certain  Ameri- 
can inventors,  including  Dr.  Tesla,  had  in- 
vented among  other  things  an  electric  ray 
to  destroy  or  detect  a  submarine  under 
water  at  a  considerable  distance.  Mr.  Tes- 
la very  courteously  granted  the  writer  an 


"Well,"  said  Dr.  Tesla,  "I  have  several 
distinct  ideas  regarding  the  subjugation  of 
the  submarine.  But  lest  we  forget,  let  us 
not  underestimate  the  efficiency  of  the 
means  available  for  carrying  on  submarine 
warfare.  We  may  use  microphones  to  de- 
tect the  submarine,  but  on  the  other  hand 
the  submarine  commander  may  employ 
microphones  to  locate  a  ship  and  even  tor- 
pedo it  by  the  range  thus  found,  without 
ever  showing  his  periscope  above  water. 

"Many  years  ago  while  serving  in  the  ca- 


duce  an  extremely  fine  cocoon  fiber  for  the 
galvanometer  suspension.  Further,  the 
galvanometer  proved  very  sensitive  for  the 
location  in  which  it  was  to  be  used ;  so  a 
special  cement  base  was  sunk  in  the  ground 
and  by  using  a  lead  sub-base  suspended  on 
springs  all  mechanical  shock  and  vibration 
effects  were  finally  gotten  rid  of. 

"As  a  matter  of  actual  personal  experi- 
ence," said  Dr.  Tesla,  "it  became  a  fact 
that  the  small  iron-hull  steam  mail-packets 
(ships)  plying  up  and  down  the  river  Seine 


229 


230 


THE  ELECTRICAL  EXPERIMENTER 


August,  1917 


BRITISH  WOUNDED  HEAR  LON- 
DON'S FAVORITES  VIA 
TELEPHONE. 

The  free  Electrophone  Service,  con- 
tributed by  public-spirited  people  of  Lon- 
don to  the  hospitals  in  that  city,  includes 
an  installation  by  which  a  hundred  patients 
can  listen,  whilst  ly- 
ing in  bed,  to  the  per- 
formances transmitted 
from  the  stages  of 
the  leading  musical 
comedy  theaters  and 
music  halls  in  Lon- 
don. The  accompany- 
ing illustration  shows 
some  patients,  with 
their  mascot  enjoying 
a  performance.  It  is 
probable  that  some 
similar  arrangement 
will  be  made  in  this 
country  when  the  reg- 
ular and  auxiliary 
hospitals  become  filled 
with  wounded  soldiers 
and  sailors.  The  tele- 
phone has  made  un- 
precedented strides  in 
America  where  there 
are  more  telephones 
per  capita  than  in  any 
other  country  in  the 
world.  There  are 
more  telephones  in 
New  York  City  than 
in  all  Europe. 

Hence,  with  such 
extension  telephone 
facilities  available,  the 
American  convales- 
cents will  surely  fare 
as  well  as  their  allies. 
Connection  with  band 
and  orchestra  concerts 
would  seem  very  suit- 
able. 


ELECTRICITY  AND  MILK 
PRODUCTION. 

The  shortage  of  milk,  due  largely  to 
difficulties  of  transport,  suggests  another 
field  of  agricultural  work  where  electricity 
can  do  good  service.  The  transport  of 
milk  and  agricultural  produce  is  largely  a 


The  Hospitals  of  London,  England,  Are  Fitted  with  Special  Telephone  Instruments  So  That 
the  Wounded  Soldiers  Can,  As  They  Lie  in  Bed,  Listen  to  the  Latest  Music  Direct  from  the 
Theaters  and  Music  Halls.    Even  the  "Mascot"  Enjoys  It. 


matter  of  providing  light  electric  railways. 
In  the  pastoral  districts  in  parts  of  Wales 
and  Ireland,  for  example,  facilities  for 
carrying  such  produce  are  almost  non-ex- 
istent, and  this  has  always  been  a  check 
on  agricultural  production,  as  well  as  po- 
tential industrial  resources.  In  the  dairy 
electrical  appliances 
have  fully  justified 
their  value,  and  it  only 
requires  electric  pow- 
er to  be  available  for 
them  to  be  much  more 
used.  The  prejudice 
against  the  milking 
machine  has  now  been 
largely  overcome,  and 
experts  believe  that 
its  action  is  more  re- 
liable than  milking  by 
hand,  especially  as 
skilled  milkmaids  are 
now  difficult  to  obtain 
in  England  and  Ire- 
land. Refrigerating 
machinery,  again 
plays  a  great  part  in 
preserving  milk  and 
enabling  it  to  be  trans- 
ported for  long  dis- 
tances, and  electrical- 
ly driven  centrifugal 
separators  for  re- 
moving the  cream  are 
great  time  savers.  The 
use  of  mechanical 
methods  is  also  of  as- 
sistance in  maintain- 
ing cleanliness  and  in 
sterilization. 

The  electrical  dairy- 
maid is  growing  to  be 
more  of  a  reality 
every  day,  especially 
in  the  United  States. 


oy  Central  Ne 


at  a  distance  of  3  miles  would  distinctly 
affect  the  galvanometer !" 

"How  could  this  be  applied  to  the  sub- 
marine problem?"  I  asked. 

"Well,  for  one  thing,"  the  scientist  re- 
plied, "I  believe  this  magnetic  method  of 
locating  or  indicating  the  presence  of  an 
iron  or  steel  mass  might  prove  very  prac- 
tical in  locating  a  hidden  submarine.  And 
it  is  of  course  of  paramount  importance 
that  we  do  find  a  means  of  accurately  lo- 
cating the  sub-sea  fighters  when  they  are 
submerged,  so  that  we  can,  with  this  in- 
formation, be  ready  to  close  in  on  them 
when  they  attempt  to  come  to  the  surface. 
Especially  is  this  important  when  several 
vessels  are  traveling  in  fleet  formation ; 
the  location  and  presence  of  the  enemy 
submarine  can  be  radiographed  to  the  other 
vessels  by  the  one  doing  the  magnetic  sur- 
veying and,  by  means  of  nets  in  some  cases, 
or  gun-fire  and  the  use  of  hydro-aeroplanes 
sent  aloft  from  the  ships,  the  enemy  under 
water  stands  a  mighty  good  chance  of  be- 
ing either  'bombed,'  shelled  or  netted. 

"However,  a  means  would  soon  be  found 
of  nullifying  this  magnetic  detector  of  the 
submerged  undersea  war-craft.  They  might 
make  the  'U-boat'  hulls  of  some  non-mag- 
netic metal,  such  as  copper,  brass,  or  alumi- 
num. It  is  a  good  rule  to  always  keep  in 
mind  that  for  practically  every  good  in- 
vention of  such  a  kind  as  this,  there  has 
always  been  invented  an  opposite,  and 
equally  efficient  counteracting  invention." 

"How  about  this  new  electric  ray  method 
of  locating  submarines?"  I  ventured  to  ask. 

"Yes,  yes,  I  am  coming  to  that,"  the 
master  electrician  parried.  "Now  suppose 
that  we  erect  on  a  vessel,  a  large  rect- 
angular helice  or  inductance  coil  of  insu- 
lated wire.  Actual  experiments  in  my 
laboratory  at  Houston  Street  (New  York 


City),  have  proven  that  the  presence  of  a 
local  iron  mass,  such  as  the  ship's  hull, 
would  not  interfere  with  the  action  of  this 
device.  To  this  coil  of  wire,  measuring 
perhaps  400  feet  in  length  by  70  feet  in 
width  (the  length  and  breadth  of  the  ship) 
we  connect  a  source  of  extremely  high  fre- 
quency and  very  powerful  oscillating  cur- 
rent. By  this  means  there  are  radiated 
powerful  oscillating  electro-static  currents, 
which  as  I  have  found  by  actual  experi- 
ment in  my  Colorado  tests  some  years  ago, 
will  first  affect  a  metallic  body  (such  as  a 
submarine  hull,  even  tho  made  of  brass  or 
any  other  metal ) ,  and  in  turn  cause  that 
mass  to  react  inductively  on  the  exciting 
coil  on  the  ship.  To  locate  an  iron  mass 
it  is  not  necessary  to  excite  the  coil  with 
a  high  frequency  current ;  the  critical  bal- 
ance of  the  coil  will  be  affected  simply  by 
the  presence  of  the  magnetic  body.  To  be 
able  to  accurately  determine  the  direction 
and  range  of  the  enemy  submarine  four 
exciting  inductances  should  be  used.  With 
a  single  inductance,  however,  it  would  be 
possible  to  determine  the  location  of  a  sub- 
marine by  running  the  ship  first  in  one 
direction  and  then  in  another,  and  noting 
whether  the  reactive  effect  caused  by  the 
presence  of  the  submarine  hull  increased 
or  decreased.  The  radiating  inductance 
must  be  very  sharply  attuned  to  the  measur- 
ing apparatus  installed  on  the  ship,  when 
no  trouble  will  be  found  in  detecting  the 
presence  of  such  a  large  metallic  mass  as 
a  submarine,  even  at  a  distance  of  5  to  6 
miles ;  of  this  I  feel  confident  from  my 
past  experiments  in  the  realm  of  ultra- 
high frequency  currents  and  potentials." 

"What  particular  experiments  do  you 
have  in  mind,  Dr.  Tesla?"  I  asked. 

"The  Colorado  tests  of  1898-1900.  Won- 
derful  were   the    results    there  obtained, 


both  those  anticipated  as  well  as  those  un- 
expected. As  an  example  of  what  has 
been  done  with  several  hundred  kilowatts 
of  high  frequency  energy  liberated,  it  was 
found  that  the  dynamos  in  a  power  house 
six  miles  away  were  repeatedly  burned  out, 
due  to  the  powerful  high  frequency  cur- 
rents set  up  in  them,  and  which  caused 
heavy  sparks  to  jump  thru  the  windings 
and  destroy  the  insulation !  The  lightning 
arresters  in  the  power  house  showed  a 
stream  of  blue-white  sparks  passing  be- 
tween the  metal  plates  to  the  earth  con- 
nection. I  could  walk  on  the  sand  (ordi- 
narily considered  a  very  good  insulator) 
several  hundred  feet  from  my  large  high 
frequency  oscillator,  and  sparks  jumped 
from  my  shoes !  At  such  distances  all  in- 
candescent lamps  glowed  by  wireless  pow- 
er, and  banks  of  lamp,  connected  to  a  few 
turns  of  wire  arranged  in  a  coil  on  the 
ground,  were  lighted  to  full  brilliancy. 
The  effect  on  metallic  objects  at  consider- 
able distances  was  really  remarkable." 

I  asked  him  about  the  "Ulivi  ray,"  which 
was  accorded  considerable  newspaper  pub- 
licity some  time  ago. 

"The  'Ulivi  ray'  really  was  transplated 
from  this  country  to  Italy,"  asserted  Dr. 
Tesla.  "It  was  simply  an  adaptation  of  my 
ultra-powerful  high-frequency  phenomena 
as  carried  out  in  Colorado  and  cited  pre- 
viously. With  a  powerful  oscillator  de- 
veloping thousands  of  horsepower  it  would 
become  readily  possible  to  detonate  powder 
and  munition  magazines  by  means  of  the 
high  frequency  currents  induced  in  every 
bit  of  metal,  even  when  located  five  to  six 
miles  away  and  more.  Even  a  powder  can 
would  have  a  potential  of  6,000  to  7,000 
volts  induced  in  it  at  that  distance. 

{Continued  on  page  270) 


August,  1917 


THE  ELECTRICAL  EXPERIMENTER 


231 


Electric  Submarine  Forts  to  Destroy  Submarines 


A NOVEL  method  of  destroying  the 
stealthy  submarine  is  here  illus- 
trated and  described.  It  is  the 
invention  of  Mr.  H.  Hartman,  a 
consulting  engineer  of  New  York 
City,  whose  Submarine  Camera,  Electric 
Speaking  Clock,  Automatic  Electric  Light 
Buoy,  Automobile  Direction  Signal,  et  cet- 
era, have  been  described  and  illustrated  in 
previous  numbers  of  The  Electrical  Ex- 
perimenter. 

The  present  invention  relates  to  a  Sub- 
marine Exploration  Device  which  origi- 
nally has  been  intended  only  for  the  pur- 
pose of  conducting  submarine  exploration 
and  salvage  operations  at  such  depths  of 


ber,  and  a  number  of  instruments  like 
water-pressure  gage,  volt  and  ammeters, 
switches,  telephone,  etc. 

Attached  below  the  main  cylinder  is  an 
auxiliary  casing,  closed  watertight  and  con- 
taining a  second  storage  battery  for  the 
purpose  of  overcoming  the  buoyancy  of 
the  main  body.  This  auxiliary  casing  can 
be  dropt  at  will  by  the  operator  in  case 
of  emergency;  for  instance,  if  the  wire 
rope  from  which  the  whole  device  is  low- 
ered into  the  water  should  break,  in  which 
case  the  main  body  would  rise  by  buoy- 
ancy to  the  surface  of  the  water. 

Furthermore,  there  is  provided  at  the 
rear  of  the  main  cylinder  an  electrically 


tight  partition,  so  that  no  water  can  enter 
the  same  in  case  that  the  large  lens  thru 
which  the  light  is  projected  into  the  water 
should  break  under  the  high  pressure  pre- 
vailing at  great  depths.  The  water-tight 
cover  of  the  main  cylinder  contains  a 
special  cooling  arrangement  which  is  re- 
quired, as  otherwise  the  heat  emanating 
from  the  light  projector  would  rise  to  a 
dangerous  degree,  which  could  cause  the 
bursting  of  the  large  lens ;  nevertheless 
the  same  is  protected  by  an  inner  circle 
of  transparent  mica  with  small  openings 
thru  which  the  heated  nitrogen  gas,  filling 
this  compartment,  may  only  gradually  and 
slowly  circulate  before  striking  the  large 


"Why  Not  Mine  Harbor  Approaches  and  Other  Shallow  Waters  with  a  Series  of  Submarine  Forts  Like  Those  Here  Shown?"  Asks  a  New 
York  Inventor.    They  Would  Carry  Powerful  Sub-sea  Searchlights,  Microphones,  Telephone  (Connecting  with  Shore  Station),  and  Spe- 
cial Torpedo  Tubes  for  Torpedoing  the  Enemy  Submarines,  Should  They  Come  Within  Range. 


the  sea  which  are  beyond  the  reach  of  a 
diver,  but  this  device  can  also  be  adapted 
successfully  for  warfare  against  enemy 
submarines  and  especially  for  the  protec- 
tion of  entrances  to  harbors,  rivers,  bays 
and  more  or  less  narrow  water-ways  as 
well  as  for  the  defense  of  vital  parts  of 
the  coast. 

This  device,  on  which  the  U.  S.  Patent 
Office  has  granted  letters  patent  to  Mr.  H. 
Hartman,  consists  mainly  of  a  vertically 
arranged  strong  steel  cylinder  of  25"  to 
30"  inner  diameter  which  can  be  closed 
water-tight  at  the  top,  providing  sufficient 
room  for  an  operator  and  also  containing 
within  special  compartments  a  powerful 
electric  search-light,  a  storage  battery,  a 
photographic  camera,  the  appliances  neces- 
sary for  the  absorption  of  the  carbon 
dioxid  exhaled  by  the  operator  as  well  as 
for  supplying  the  oxygen  required  to  re- 
vitalize the  air  within  the  operator's  cham- 


operated  screw  propeller  which  will  rotate 
the  whole  suspended  (or  anchored)  unit 
round  its  vertical  axis  if  desired  by  the 
operator.  The  main  cylinder  is  divided 
into  three  separate  compartments  as  is 
shown  in  the  picture.  The  lowermost 
compartment  contains  a  storage  battery 
of  high  capacity  and  sufficient  evacuated 
space  to  take  up  any  gas  which  the  bat- 
tery may  develop  during  its  discharge 
action. 

Hermetically  sealed  from  this  compart- 
ment follows  the  operator's  chamber  in 
which  a  man  may  comfortably  ride  on  an 
elastic  saddle  and  observe  the  surround- 
ing waters  thru  a  system  of  heavy  lenses 
which  are  set  carefully  and  watertight  into 
the  steel  cylinder.  To  illuminate  the 
water  a  very  powerful  electric  searchlight 
is  arranged  within  the  next  or  top  com- 
partment, which  in  its  turn  is  also  divided 
from  the  operator's  chamber  by  a  water- 


lens  which  is  cooled  from  outside  by  the 
icy  waters  of  the  depth. 

The  operator  can  not  only  swing  the 
light  projector  under  different  angles  by 
means  of  electro-magnets  but  also  rotate 
the  whole  device  slowly  round  its  vertical 
axis  and  incline  the  same  to  a  certain  de- 
gree and  observe  the  surrounding  water 
in  every  direction.  A  telephone  connec- 
tion, whose  insulated  conductors  are  em- 
bedded into  the  core  of  the  wire  rope 
from  which  the  device  is  suspended  into 
the  water,  permits  the  operator  to  remain 
in  constant  communication  with  his  mother 
ship  and  to  report  at  once  everything  he 
sees  and  also  to  direct  salvage  operations, 
when  so  used.  The  submarine  fort  can 
also  be  anchored  as  shown,  the  top  cable 
running  to  a  submerged  buoy.  A  string 
of  these  forts  could  be  placed  across  the 
entrance  of  a  harbor  or  bay. 

{Continued  on  page  270) 


232 


THE  ELECTRICAL  EXPERIMENTER 


August,  1917 


Putting  the  Ocean  Waves  to  Work 


IF  there  is  any  one  invention  that  has 
been  well-nigh  worked  to  death,  it  is 
that  which  tends  in  some  way  or  other 
to  make  practical  use  of  the  boundless 
energy  in  the  ocean  waves.    But,  re- 
gardless of  all  the  study  and  work  that 
has  been  expended  on  this  engrossing  and 
worthy  problem,   all   attempts   up  to  the 


By  CHARLES  W.  GEIGER 

by  water  at  low  tide.  These  wheels,  by 
the  merit  of  the  novel  clutch  used,  have 
an  absolute  freedom  and  independence  one 
from  the  other,  even  tho  they  play  on  a 
common  power  shaft.  In  this  manner  any 
vibrating  tendency  of  the  swell  is  imme- 
diately disposed  of  as  driving  energy  on 
power  generating  units.    The  machine  now 


Fig.  2 — Another  View  of  the  Hydraulic  (Compound  Pump  and  Turbine)  Type  of  Wave  Motor 
Shown  Below.     Depending  Paddles  Are  Actuated  by  the  Waves  and  Every  Bit  of  Motion 

Is  Put  to  Useful  Work. 


present  time  have  signally  failed  to  pro- 
duce any  satisfactory  results  in  putting 
these  ever-rolling  walls  of  water  to  work. 
It  must  have  exasperated  many  an  engi- 
neer to  see  this  tremendous  power  con- 
tinually going  to  waste.  But  indomitable 
courage  and  resourcefulness  will  overcome 
almost  any  obstacle  as  long  as  it  comes 
within  the  pale  of  practicability. 

Just  to  show  that  there  is  a  way  to 
harness  the  industrious  waves  and  break- 
ers, two  California  inventors  have  worked 
out  what  seems  to  be  a  start  in  the  right 
direction,  as  the  accompanying  photographs 
bear  testimony,  illustrating  as  they  do, 
two  distinct  types  of  wave  motors  in- 
stalled at  Long  Beach,  California.  They 
are  intended  to  develop  considerable  power 
and  to  show  that  it  is  possible  to  develop 
electrical  energy  more  cheaply  than  by 
burning  coal  or  by  other  means.  The 
view,  Fig.  1,  shows  the  extensive  wave 
power  plant  now  being  installed  in  com- 
mercial capacity  at  Long  Beach,  California. 
The  wave  motor  here  presented  displays 
a  wide  divergence  from  the  wave  motors 
of  past  experimentation. 

The  unique  feature  of  this  new  machine 
is  a  compound  uni-directional  or  free-draw 
and  release  clutch.  This  clutch  is  an 
achievement  in  rotating  a  power  shaft  in 
such  a  manner  as  to  free  the  same  from 
all  dead  center  action,  as  well  as  creating 
rolling  energy  with  the  condition  of  no 
given  stroke.  So  perfect  is  the  action  of 
the  clutch  employed,  it  is  said,  that  any 
vibrational  action  is  immediately  trans- 
formed into  a  continuous  rotary  impulse. 
The  machinery  employed  utilizes  for  its 
driving  energy  the  reciprocating  action  of 
the  ground  swell  occurring  in  ocean  water. 
This  action  being  caused  by  volumetric  dis- 
placement as  the  wave  moves  forward  set- 
ting up  compound  actions  in  opposite,  a 
feature  that  no  other  motor  possesses. 

Substantially  the  machine  consists  of  a 
multiple  number  of  large  bull-wheels  each 
actuated  by  an  impulse  paddle,  well  covered 


being  installed  will,  when  fully  completed, 
present  an  ultimate  capacity  of  some  three 
to  four  thousand  horse-power. 

This  machine,  aside  from  presenting  the 
required  feature  of  being  a  continuous 
power  producer  operating  irrespective  of 
surface  action,  also  possesses  the  merit  of 
being  a  storm  resistant  machine,  being  the 
only  one  of  its  kind  having  no  resistance 
to  start,  and  at  no  time  experiencing  back 
pressure  effects. 
The  device  was 
thoroly  tested 
and  proven  by 
the  operation  of 
a  demonstrating 
plant  which  ex- 
perienced the  ac- 
tion of  two  of 
the  heaviest 
storms  that  has 
occurred  on  the 
Pacific  coast  for 
a  period  of  twen- 
ty -  five  years, 
without  the 
slightest  damage. 

With  its  wave 
power  equipment 
the  company  an- 
ticipates the  pro- 
duction of  elec- 
tric energy  on  a 
wholesale  basis, 
at  about  90%  of 
the  cost  of  pro- 
duction by  steam, 
and  75%  of  the 
cost  of  produc- 
tion by  present- 
day  hydro  -  elec- 
tric methods.  Ac- 
cording to  the 
best  of  author- 
ity it  will  be  pos- 
sible even  under 
the  present  strest 
condition  of 


the  steel  market  to  install  these  plants  at 
the  surprising  figure  of  $30.00  per  horse- 
power. 

In  actuating  the  power  shaft,  oscillating 
bull-wheels  are  connected  by  heavy  54-inch 
plow-steel  cables,  which  engage  the  impulse 
wheels  actuating  the  clutch  units  by  mul- 
tiple series  of  turns  on  the  same.  By  direct 
connection  on  side  and  reverse  connection 
on  the  opposite  side,  the  continual  rota- 
tion of  the  power  shaft  is  readily  main- 
tained. The  bull-wheels  employed  in  driv- 
ing the  power  shaft  are  of  a  six-sector 
bridged  arc  type,  24  feet  in  diameter,  built 
to  resist  fractious  stress  on  two  one-inch 
steel  cables.  These  wheels  are  so  disposed 
as  six  units  to  incorporate  within  the  ma- 
chine the  action  of  two  ground  swells  at 
any  one  time,  taking  varied  action  so  as 
to  afford  a  steadied  maintenance  of  power 
at  all  times. 

Mr.  Alva  L.  Reynolds,  the  inventor  of 
the  second  type  of  wave  motor  being  in- 
stalled at  Long  Beach,  shown  at  Figs.  2 
and  3,  possesses  several  promising  feat- 
ures. 

This  wave-motor  is  of  the  hydraulic 
transmission  and  regulation  type.  The 
paddles  are  actuated  with  any  kind  of  a 
wave,  and  either  forward  or  backward 
movements  of  the  paddle  are  transmitted 
into  energy.  The  paddle  is  connected  to 
a  pendulum  shaft  with  a  sprocket  as  shown. 
This  sprocket  actuates  a  chain  that  is  con- 
nected with  a  sprocket  on  the  shaft  that 
drives  the  pumps.  On  the  drive  shaft  is 
a  crank  connected  with  the  pumps  by 
means  of  a  connecting  rod.  These  pumps 
were  designed  for  this  special  work  in 
this  special  position.  The  chain  and  cog- 
wheel that  drives  the  crank-shaft  is  seen 
near  the  left  edge  of  the  picture.  Each 
movement  of  the  paddle  moves  this  crank- 
shaft and  by  means  of  the  connecting  rod 
works  the  pumps.  There  are  two  pumps  to 
each  pendulum.  There  is  another  crank- 
shaft on  the  end  of  the  drive-shaft  that 


Fig.  3 — Perspective  View  of 
Type  of  Wave  Motor 


New  Hydraulic  Transmission  and  Regulation 
Installed  At  Long  Beach,  California. 


August,  1917 


THE  ELECTRICAL  EXPERIMENTER 


233 


actuates  the  pump  seen  to  the  left  of  the 
picture.    There  are  four  pumps  altogether 
in  this  unit  and  two  pendulums. 
As  the  water  is  comprest  by  the  pumps, 


Fig.  1 — A  Second  Type  of  Wave  Motor  Being  Installed  At  Long 
Beach,  Calif.  The  Waves  Actuate  Dependent  Paddles  Attached  to 
the  Large  Bull-Wheels  (Top  Photo).  Continuous  Rotary  Motion 
Is  Obtained  by  the  Remarkably  Sensitive  Free-Draw  and  Release 
Clutches  Used  (Lower  View). 

it  passes  thru  a  large  pressure  tank  (seen 
to  the  right  in  the  large  picture).  This 
takes  the  pulsating  effect  of  the  pumps 
out  of  the  water  and  leaves  a  perfectly 
steady  stream  for  the  water  wheels.  This 
water,  under  120  pounds  pressure,  runs  a 
water  turbine  which  in  turn  is  connected 
to  the  electric  generator. 

The  power  thus  generated  is  at  pres- 
ent used  for  lighting  purposes  and  for  a 
large  search-light.  The  generator  is  also 
connected  to  storage-batteries,  which  are 
charged  when  there  is  plenty  of  water 
power  in  preparation  for  the  time  when 
the  ocean  may  be  comparatively  calm. 


lumination  increases.  The  selenium  cells 
operate  a  siphon  recorder  or  a  relay.  There 
being  no  physical  connection  between  the 
recorder  or  relay  and  the  line  galvano- 
meter, the  inertia 
and  frictional  losses 
present  in  the  older 
magnifying  and  re- 
cording apparatus 
are  largely  eliminat- 
ed, the  more  so  as  in 
the  new  system  the 
amplitude  of  vibra- 
tion of  the  galva- 
nometer coil  is,  in 
general,  much  less 
than  in  the  case  of 
the  older  apparatus. 
It  is  stated  that  Mr. 
Dixon  employed  45 
separate  light  beams, 
all  derived  from  one 
40  0  candle  -  power 
tungsten  lamp,  and 
all  concentrated  on 
a  thin  galvanometer 
mirror  5  inches  long 
and  Y%  inch  wide. 
These  light  beams 
were  reflected  from 
the  galvanometer 
mirror,  in  one  case, 
a  distance  of  7  feet 

6  inches,  and  were 
then  reflected  a 
further  distance  of 

7  feet  6  inches  to 
the  selenium  cells, 
the  light  beams  be- 
ing concentrated  co- 
incidently  upon  the 
cells. 

With  this  appar- 
atus, working  over 
one  of  the  transat- 
lantic cables  the  nor- 
mal rate  of  operation 
of  which  is  less  than 
two  hundred  letters 
per  minute,  a  speed 
of  450  letters  per 
minute  and  higher  was  obtained  in  the  reg- 
ular commercial  handling  of  business,  and 
still  higher  speeds  have  been  obtained  on 
tests,  with  signals  fully  readable  as  to  size 
and  character. 


GROWTH    OF    ELECTRIC  STEEL 
FURNACE  INDUSTRY. 

In  1908  there  was  one  electric  steel  fur- 
nace in  the  United  States  with  an  annual 
production  of  55  tons.  January  1st  of  this 
year  there  were  136  furnaces  reported,  as 
compared  with  73  in  use  in  1916.  The 
electric  furnace  can  no  longer  be  said  to 
be  in  the  experimental  stage,  with  20-ton 
furnaces  in  regular  operation. 


SELENIUM  SPEEDS  UP  THE 
OCEAN  CABLE. 

A  new  invention,  devised  by  Mr.  J.  B. 
Dixon,  has  been  in  practical  operation  on 
certain  of  the  Atlantic  cables,  and  is  re- 
ported to  have  given  remarkable  results, 
the  speed  of  operation  in  the  commercial 
handling  of  cable  messages  has  been  in- 
creased upwards  of  125  per  cent,  while  in 
tests  far  greater  speeds  have  been  attained. 
The  gain  in  speed  is  due  to  the  use  of 
selenium  cells  to  amplify  the  signals  re- 
ceived, and  to  the  use  of  means  for  ob- 
taining, from  one  or  more  sources  of  illu- 
mination, a  very  large  number  of  light 
beams,  concentrated  coincidently  upon  se- 
lenium cells,  and  deflected  by  a  line  gal- 
vanometer across  the  surface  of  the  cells, 
the  effect  being  that  a  very  intense  illumi- 
nation of  the  cells  is  obtained. 

It  is  found  that  the  practicable  speed  of 
operation  increases  as  the  intensity  of  il- 


ELECTRIC  TRAPSHOOTERS  WHO 
"NEVER  MISS"  ARE  NO 
MORE. 

For  the  past  16  months,  from  sunset  to 
sunrise,  the  electrically  operated  trap- 
shooters  on  the  world's  largest,  most  at- 
tractive, realistic  and  spectacular  electric 
sign — located  on  the  Million  Dollar  Pier, 
Atlantic  City,  N.  J. — have  fired  at  10  tar- 
gets a  minute  and  recorded  a  "hit"  every 
time. 

Human  trapshooters  are  not  equal  to 
the  task  of  breaking  every  target  thrown. 
Mechanisms,  of  course,  can  be  made  al- 
most infallible,  but  mark  you,  from  now 
on,  the  electrical  trapshooters  are  to  be 
more  realistic  and  more  human  than  ever. 
They  will  miss  at  irregular  intervals.  Ir- 
regular is  the  proper  word. 

Thousands  of  persons  seat  themselves 
on  the  spacious  hotel  verandas  and  many 
more  mass  on  the  boardwalk  every  night 


trying  to  figure  out  when  the  shooter  will 
miss.  Sometimes  the  misses  are  as  many 
as  two  or  three  in  thirty  seconds — while 
at  other  times  the  misses  are  not  more 
than  two  in  the  same  number  of  minutes. 
Therefore  it  is  difficult  to  work  out  a  sys- 
tem and  play  it. 

Figuring  out  "when  the  shooter  misses" 
has  become  quite  a  game  in  Atlantic  City, 
and  every  one  is  playing.  You  cannot 
help  but  enthuse  and  get  into  the  game 
after  watching  the  electrical  display.  It 
is  only  human  to  try  and  solve  the  puzzle 
— and  ascertaining  just  when  the  shooter 
misses  is  a  puzzle.  Thousands  check  up 
the  misses  each  night,  keeping  tabs  by  the 
hour,  but  on  no  two  nights  thus  far  has 
the  rotation  of  misses  been  the  same. 

It  took  five  months  of  incessant  schem- 
ing and  testing  to  perfect  the  scheme  of 
having  the  shooters  miss,  and  the  changes 
had  to  be  made  so  as  not  to  affect  the  oper- 
ation of  the  sign.  The  iron  work  was  ex- 
tended 10  feet  and  several  hundred  addi- 
tional lights  are  now  in  operation. 

This  is  the  second  change  that  has  been 
made  in  the  working  of  the  great  sign 
since  it  was  first  shown  to  public  view — 
January  4,  1916.  The  original  shooter  was 
a  man.  Then  the  idea  was  suggested  to 
have  a  woman  alternate  with  the  man  in 
firing  at  the  targets.  This  wonderful  ac- 
complishment was  perfected  and  the  fair 
Diana  began  alternating  with  the  male 
shooter  several  months  after  the  first  oper- 
ation of  the  sign. 

There  are  4,000  lights  in  the  entire  sign, 
which  is  50  by  100  feet.  The  figures  of 
the  shooters  are  21  feet  high.  The  trap 
puller  is  18  feet  6  inches  tall.  The  target 
is  15  inches  in  diameter.  The  sign  cost 
upwards  of  $100,000. 

There  are  six  operations  to  the  sign, 
each  one  taking  about  one  second.  First 
the  green  lights  come  on,  producing  a  lawn 
effect,  and  then  in  order  appears  the  trap- 
shooter,  who  places  his  gun  to  his  shoul- 
der and  aims  as  the  trap  puller  rises  be- 
hind him.  The  puller  throws  the  lever, 
which  releases  the  target.  You  soon  learn 
whether,  the  target  is  hit  or  mist.  When 
hit,  the  target  bursts  into  hundreds  of 
small  lights,  looking  for  all  the  world 
like  the  fragments  of  a  target.  When 
the  target  is  mist  it  travels  the  length  of 
the  sign  and  disappears  into  the  fourth 
dimension — inky  blackness. 

It  is  a  most  interesting  display,  and  has 




Atlantic  City  Crowds  Are  Now  Kept  Busy 
Figuring    When    the    Electrical  Trapshooter 
Is  Going  to  "Miss." 

proved  the  only  means  so  far  of  grafically 
depicting  the  actual  sport  of  trapshooting 

by  mechanical  effects. — Photos  courtesy  of 
R.  C.  Maxwell  Co. 


234  THE  ELECTRICAL  EXPERIMENTER  August,  1917 

Blinding  The  Submarine 


THERE  is  one  dead  sure  way  of 
making  a  ship  torpedo-proof  and 
that  is  by  making  it  invisible.  No 
one  will  deny  this.  For  if  the  sub- 
marine commander  can't  see  his 
quarry  he  can't  torpedo  it.  Now,  this  is 
not  intended  as  a  joke,  nor  do  I  refer  to 
Grimm's  Fairy  Tales,  where  the  young 
prince  by  the  turn  of  his  magic  cap  be- 


By  H.  GERNSBACK 

Experiment  2.  Have  an  assistant  throw 
the  full  glare  directly  into  your  eyes.  You 
will  be  blinded  for  several  seconds. 

Experiment  3.  Try  experiment  2  in 
broad  daylight,  but  with  the  searchlight 
detached  from  the  auto.  Ask  your  assist- 
ant to  move  to  one  side  of  the  car.  Have 
him  train  the  full  glare  into  your  face.  It 
will  be  impossible  for  you  to  see  the  car, 


City  by  us.  "But,  what  is  the  good  of 
them,"  you  will  ask.  Here  is  the  answer : 
Consider  that  the  submarine  commander, 
in  order  to  look  thru  his  periscope,  must 
of  necessity  be  in  the  dark,  or  at  least 
his  quarters  immediately  surrounding  him 
must  be  more  or  less  subdued  and  shielded 
from  light.  You  know  you  cannot  look 
thru  a  telescope  at  a  distant  object  without 


DIRECTION  OE  SHIP  \ 
2  SEARCHLIGHTS^ 


pOfiTCROWSNESTCONTtOL 


SEARCHLIGHTS 


Fig  1.  Keeping  Very  Powerful  Searchlights  Trained  On  the  U-Boat  Periscope,  Makes  It  I mpossible  for  Its  Commander  to  Take  the  Attacked 

Ship's  Bearings.    The  Searchlights  Are  Used  In  Broad  Daylight.    Now  See  Fig.  2. 


comes  invisible  to  all.  Rather  I  wish  to 
stay  within  the  realms  of  common  physics, 
and  present  day  physics  at  that. 

After  all,  what  is  visibility?  It  is  that 
which  is  perceptible  to  the  eye.  A  ship 
visible  in  broad  daylight  is  invisible  in  a 
dead  black  night.  But  visibility  depends 
upon  sight,  so  that  a  ship  visible  to  you 
in  broad  daylight  is  invisible  to  the  blind 
man.    All  this  is  obvious. 

Our  problem  as  applied  to  submarine 
warfare  then  resolves  itself  in  blinding  the 
submarine  commander,  so  that  he  cannot 
see  the  ship  he  wishes  to  attack.  Can 
this  be  done?  I  am  certain  of  it.  And 
what  is  more,  the  plan 
which  I  advance  herewith  ^m^— 
is  so  idiotically  simple,  that 
probably  just  on  account 
of  its  very  simplicity  it  has 
not  been  tried  before.  It 
is  the  old  story  of  Colum- 
bus and  the  egg — it  is  sim- 
ple if  you  know. 

In  order  to  understand 
what  I  mean  let  us  try  a 
few  simple  experiments. 

Experiment  1.  Light  up 
a  powerful  auto  search- 
light tonight,  only  one  tho. 
The  auto  must  be  in  ^——^^^^ 
the  dark.  Now  station 
yourself  50  yards  away.  Do  not  look 
directly  into  the  shaft  of  light.  Can  you 
tell  zuhere  the  driver  sits?  You  cannot. 
You  simply  see  the  light  shaft,  that  is  all. 
But  you  can't  see  where  the  car  is,  and 
whether  it  is  the  right  or  the  left  search- 
light that  is  lighted. 


even  with  the  sun  shining  on  it.  You  are 
blinded  in  broad  daylight.  This,  of  course, 
providing  that  the  searchlight  is  sufficiently 
powerful.  If  you  don't  own  a  searchlight 
try  a  mirror,  and  have  your  assistant  re- 
flect the  sunlight  into  your  eyes.  Try  as 
you  may,  you  will  never  as  much  as  glimpse 
an  object  within  500  feet  of  either  side  of 
him. 

Experiment  4.  Repeat  experiment  3, 
but  protect  your  eyes  by  black  glasses 
(smoked  glasses).  You  will  find  that  it 
won't  help  you  at  all.  Instead  of  a  ball 
of  white  fire  you  now  get  a  ball  of  orange 
fire  into  your  eyes.    Less  blinding,  true — 


When  a  U-boat  Commander  wishes  to  torpedo  your  ship  he  must  know 
three  things: 

1st    He  must  know  the  speed  of  your  vessel. 
2nd    He  must  know  in  which  direction  you  move. 

3rd  He  must  know  the  distance  measured  in  a  straight  line  from  the 
U-boat  to  your  ship. 

If  you  devise  a  means  whereby  he  cannot  make  his  observations  cor- 
rectly, the  commander  will  be  unable  to  torpedo  you.  The  idea  outlined 
in  this  article  aims  to  blind  the  U-boat  commander  in  broad  daylight  by 
means  of  powerful  searchlights,  thereby  making  it  impossible  for  him  to 
correctly  take  a  ship's  bearing. 

An  interesting  as  well  as  plausible  article,  that  will  set  you  thinking. 


placing  your  eye  close  to  the  eye-piece,  in 
order  to  shield  your  eye  from  the  light. 
Now  then  imagine  for  a  minute  that  you 
are  the  submarine  commander,  with  your 
eye  glued  to  the  as  yet  submerged  peri- 
scope. Slowly  and  cautiously  you  raise 
the  periscope  tube  till  it  is  a  foot  or  more 
above  the  water.  Rapidly  you  turn  it  in 
a  circle  to  scan  every  point  of  the  horizon. 
Nothing  but  the  blue  sky  and  the  ocean. 
You  keep  on  turning.  Suddenly  like  a 
bolt  of  lightning  your  eyes  are  filled  with 
a  ball  of  white  fire  that  makes  your  eyes 
water. 

"Donnerwetter!"  you 
will  say — presuming  that 
you  are  a  German  U-boat 
commander.  Down  comes 
the  periscope,  while  you 
wipe  your  eyes  stupidly. 
After  a  few  minutes  you 
try  again.  Once  more  you 
are  blinded  for  seconds  at 
a  time.  You  see  the  light 
but  that's  all. 


but  you  cannot  see  the  objects  to  either 
side  of  your  assistant — even  in  full  day- 
light— because  the  darkened  glass  does  not 
pass  thru  enough  light. 

You  readily  understand  these  experi- 
ments, and  they  are  correct  as  stated,  hav- 
ing been  actually  tried  out  in  New  York 


Now  to  torpedo  a  ship 
you  must  know  several 
things.  First  you  must 
^bmk  know  its  position,  that  is 
how  far  away  it  is  from 
you.  Second,  you  must  know  in  what 
direction  the  ship  is  traveling.  Third,  you 
must  know  its  speed.  Without  knowing 
these  three  things  it  is  as  a  rule  impossible 
to  torpedo  successfully. 

And  with  a  powerful  searchlight  trained 
full  on  your  periscope  you  would  of  course 


August,  1917 


THE   ELECTRICAL  EXPERIMENTER 


235 


know  where  the  ship  was,  but  you  could 
not  possibly  know  how  far  away  it  was 
from  you  as  measured  in  yards,  nor  would 
you  know  if  the  ship  was  traveling  towards 
you  or  away  from  you.  You  could  not 
know  if  the  searchlight  was  on  the  bow 
or  on  the  stern  of  the  vessel.  Neither 
would  you  know  if  the  ship  was  traveling 
at  right  angles  to  you  or  whether  it  pre- 
sented its  bow  or  stern  to  you.  Artifices 
such  as  sensitive  microphones  will  not  help 
you  much.  You  must  take  the  ship's  bear- 
ings accurately  or  you  cannot  possibly  tor- 
pedo it ;  any  naval  man  versed  in  sub- 
marine matters  will  confirm  this.  As  long 
as  the  glare  persists  you  cannot  take  your 
bearings.  And  you  don't  dare  come  up 
to  the  surface  to  walk  on  deck  of  the 
U-boat,  because  the  ship  that  has  the 
searchlight,  most  likely  will  have  guns  too. 
So  you  curse  a  full  round,  haul  down  the 
periscope  for  the  ninth  time  and  drown 
yourself  in  a  stein  of  Wiirzburger. 

My  idea  then  is  this.  Mount  on  the 
ship  four  powerful  searchlights.  Our  illus- 
tration shows  how  it  should  be  done. 
There  should  be  one  attendant  to  each 
searchlight.  Ordinarily  the  searchlights 
are  not  lighted  but  remain  dark.  Each 
searchlight  operator  wears  a  telephone 
headgear,  exactly  as  our  naval  gunners  do 
now.  Stationed  high  up  in  the  crow's  nest 
are  two  observers  scanning  the  water  at 
all  times  with  their  glasses.  One  observer 
scans  the  ocean  on  the  starboard  side,  the 
other  overlooks  the  water  "orTTffie~iJoft  side 
of  the  ship.  Strapt  to  their  breasts  is  a 
transmitter,  the  same  as  "Central"  wears. 
The  instant  the  top  of  a  periscope  is  ob- 
served, let  us  say  on  the  port  side,  the 
crow's  nest  immediately  gives  the  position 
to  the  two  port  searchlight  attendants.  By 
means  of  a  foot  operated  switch,  the  cur- 
rent is  turned  into  the  searchlight  instantly 
and  the  latter  is  trained  onto  the  periscope. 
The  searchlight  being  placed  on  ball  or 
roller  bearings,  obeys  the  touch  of  the 
finger.  Thru  a  sighting  tube  the  attendant 
will  positively  throw  the  glare  full  onto  the 
periscope  in  less  than  five  seconds  after  he 
received  the  position  from  above.  Very 
great  accuracy  is  not  necessary  for  these 
simple  reasons : 

Let  us  assume  the  U-boat  is  two  miles 
off.  At  this  distance  the  beams  of  the 
searchlight  cover  a  fan-shaped  expanse  of 
about  50  yards.  In  other  words,  if  the 
attendant  makes  a  mistake  of  25  yards  on 
either  side  of  the  periscope,  it  does  not 
matter ;  the  U-boat  commander  will  be 
blinded  just  as  efficiently.  Besides,  the 
man  behind  the  searchlight  will  correct 
his  aim  in  less  than  three  seconds,  once 
his  rays  have  hit  the  periscope. 

Observe  the  simplicity  of  the  operation. 
A  hundred  percent  hit  should  be  recorded 
every  time.  It  is  inconceivable  how  either 
of  the  two  attendants  could  fail  to  make  a 
"hit"  with  their  rays.  Note,  too,  that  the 
operation  is  unlike  firing  a  gun.  First, 
considerable  time  is  lost  in  sighting  the 


projectile  is  almost  an  impossibility.  It 
lias  never  been  done,  except  by  pure 
chance.  One  hit  in  a  thousand  would  be 
considered  good.  Consider,  on  the  other 
hand,  a  shaft  of  light  50  yards  wide,  which 
can  be  moved  instantly  over  an  expanse 
of  several  miles,  and  it  becomes  plain  why 
there  cannot  be  possibly  any  escape  for 
the  periscope. 

The  beauty  of  the  scheme  is  the  great 
speed  at  which  the  entire  operation  is  per- 
formed. Five  to  six  seconds — and  with  a 
trained  crew  it  should  be  less — is  ample 
time  once  the  periscope  is   located.  No 


submarine  commander  can  possibly  make 
his  necessary  observations  in  such  a  short 
time;  it  requires  a  minimum  of  one  min- 
ute to  take  a  ship's  bearings. 

Of  course  it  is  evident  that  the  success 
of  the  scheme  lies  in  the  ability  of  the 
lookout,  who  must  spot  the  periscope  at 
once.  This,  however,  should  not  be  so 
difficult  for  a  trained  seafaring  man. 

I  mentioned  above  that  two  searchlights 
could  and  can  be  used  simultaneously. 
For  practical  purposes  and  for  tactical  ad- 
vantages a  single  searchlight,  however,  is 
preferable  for  the  following  reasons : 

Our  front  cover  shows  how  the  search- 
lights are  mounted  on  a  long  steel  exten- 
sion projecting  some  25  feet  from  the  bow 
and  stern  of  the  ship.  This  is  done  for 
two  reasons.  First,  it  gives  the  operator 
a  better  sweep,  second  and  most  impor- 
tant, if  the  submarine  commander  should 
fire  a  torpedo  in  the  direction  of  the  light 


ci  pally  to  the  extended  location  of  the 
searchlights.  This  is  not  apparent  at  once 
but  bear  in  mind  that  the  commander 
does  not  see  the  ship  itself,  and  that  he 
does  not  know  if  the  beam  of  light  origi- 
nates from  the  bow  or  from  the  stern  of 
the  vessel  to  be  torpedoed.  Neither  does 
he  know  in  which  direction  the  ship  moves. 
Then,  too,  as  soon  as  the  enemy  periscope 
is  sighted  and  has  been  covered  by  the 
light  beam,  the  ship  can  turn  about  at 
once,  the  searchlight's  rays  however  being 
kept  on  the  periscope  all  the  while  during 
this  maneuver.    If  the  periscope  is  hauled 


down,  the  operators  have  but  to  watch  for 
its  reappearance,  when  the  game  starts 
anew.  In  the  meantime  the  commander 
of  the  ship  can  either  "zig-zag"  his  ship 
or  else  present  the  stern  of  the  ship  to- 
wards the  U-boat.  In  either  case  torpedo- 
ing is  extremely  doubtful,  and  the  attacked 
ship  should  make  good  its  escape. 

The  scheme  as  outlined  is  for  use  in 
broad  daylight,  or  rather  during  the  day- 
time, but  I  doubt  if  it  is  feasible  or.  prac- 
tical at  night.  Nor  is  it  necessary,  for 
only  comparatively  few  boats  are  sunk  be- 
tween sunset  and  sunrise.  Of  course  in 
clear  moonlight  or  in  extraordinarily  clear 
nights  where  the  visibility  is  not  too  low, 
the  searchlights  can  be  used  to  advan- 
tage. In  a  very  dark  night,  however,  it  is 
obvious  that  the  U-boat  possesses  a  great 
advantage  over  the  ship.  It  is  then  almost 
impossible  to  sight  the  small  periscope,  and 
the  U-boat  would  surely  see  the  searchlight 
much  quicker  than  the  ship's  observer 
could  see  the  U-boat.  Still  the  fact  re- 
mains that  the  submarine  commander 
would  be  baffled,  because  he  could  not  tell 
if  the  searchlight  was  in  the  center,  in  the 
bow  or  in  the  stern  of  the  ship.  It  is  there- 
fore doubtful  if  he  could  make  a  hit,  ex- 
cept perhaps  by  using  two  torpedoes  simul- 
taneously directed  fifty  yards  to  either  side 
of  the  searchlight.  But  even  then  a  hit  is  not 
at  all  certain,  because  the  ship  might  present 
its  bow  or  its  stern  to  the  U-boat,  thereby 
offering  a  very  small  target.  In  that  case 
the  torpedoes  would  of  course  pass  the 
ship  on  either  side  of  it.  The  main  re- 
quirements of  the  plan  as  outlined  are 
VERY  powerful  electric  searchlights. 
Hundreds  of  thousands  of  candlepower 
MUST  be  used,  otherwise  the  scheme  is 
(Continued  on  page  270) 


2  seorcn/ignfs 

/ 

2  seorcn/fgnfo 

J; 

:    .  -■/<  ' 

Top  view  of 
Periscope 

Fig.  2 

Direction 
of  5 flip 

_•;  ■/  "'  '■ 
Z/g.-Zag  course 
of  snip 

From  the  Ship's  Position  As  Shown  in  Fig.  1  It  Now  Swings  About— Still  Keeping  the  Search- 
lights On  the  Enemy's  Periscope — Thereby  Presenting   Its   Narrowest  Part  to  a  Possible 
Torpedo.    Then  By  Zig-Zagging,  the  Attacked  Steamer  Can  Escape. 


latter;  second,  to  hit  an  object  one  foot  rays,  even  if  he  has  the  general  position 
high  and  six  inches  in  diameter  (the  of  the  searchlight,  he  probably  would  miss 
enemy  periscope)  with  a  two  or  three  inch     the  ship  by  a  great  many  feet,  due  prin- 


 >_<  . 


\\  o 


\C3  \  — \ 

\  \  CO 

.o       \  o 


\t3  > 


A  \  I 

\  \  I 

S  \  1 

\    o.  N 

■  Vl] 


C-  Shorn  posif/on  of  affacfred  ship  of  f/me 
of  firing  of  forpedoes  by  submarine 
sfaffoned of  B" 

D  -  Doffed  fines  showing  affacAed  sh/p  where 
if  mil  be  » 'hen  forpedoes  f/9J&  Np2 
infercepf  ifs  course.. 
Nofe  ongfe  of  which  forpedoes 
musf  be  fired. 


Submarine 


To  Torpedo  a  Ship  the  Submarine  Commander  Must  Know  These  3  Things: 
1st,  Distance  from  A  to  B  in  Yards;  2nd,  Speed  of  Ship,  i.e.,  How  Long  It  will  Take  to  Travel 
from  C  to  D;  3rd,  Direction  in  Which  Ship  Is  Moving,  i.e.,  Does  It  Travel  from  C  to  D  or  from 

C  to  E? 


236 


THE  ELECTRICAL  EXPERIMENTER 


August,  1917 


Thunder-Storms  and  Lightning  Rods 


THIS  matter  of  thunder-storms  and 
lightning  rods  is  one  about  which 
many  inaccurate  impressions  exist. 
Altho  the  lightning  rod  is  the  oldest  use- 
ful electrical  invention  (it  was  first  pro- 
posed by  Benjamin  Franklin  in  1752)  it 
has  been  the  writer's  experience  that,  to- 
day, a  majority  of  otherwise  well-informed 
folks  do  not  know  whether  or  not  lightning 
rods  afford  protection  to  the  buildings  on 
which  they  are  in- 
stalled. The  subject 
is  one  of  such  uni- 
versal interest  that 
everyone  should  be 
familiar  with  the  gen- 
eral facts  relating  to 
it.  Therefore  in  this 
article  the  essential 
and  underlying  prin- 
ciples as  they  are  ex- 
plained by  the  mod- 
ern theories  will  be 
discust. 

There  are  no  ex- 
periments which  the 
reader  can  readily 
perform  to  verify  the 
facts  disclosed  in  this 
article  because  the 
electrical  qualities  in- 
volved in  lightning 
phenomena  are  of 
such  great  magnitude 
that  they  cannot  be 
accurately  reproduced 
in  the  laboratory.  In 
this  instance  he  must, 
without  verification, 
take  the  author's 
word  for  it  that  the 
statements  which  will 
be  made  are  correct. 

First  of  all,  light- 
ning rods   do,  when 
they  are  properly  in- 
stalled, afford  practi- 
cally perfect  protection  against  lightning 
damage  to  structures.   The  United  States 
Government  Bureau  of  Standards  finds  that 
even  as  they  are  ordinarily  installed — and 
they  are  not  always  in  practise  arranged  as 
effectively   as    should   be— lightning  rods 
"reduce  the  fire  hazard  from  lightning  by 
80  to  90  per  cent  in  the  case  of  houses, 
and  by  as  much  as  99  per  cent  in  the 
case  of  barns."    Inasmuch  as  some- 
thing more  than  $8,000,000  worth  of 
property   is   destroyed   annually  by 
lightning  in  our  United  States  (prac- 
tically all  of  this  loss  could  be  pre- 
vented by  the  suitable  lightning-rod 
installations),  the  importance  of  the 
subject  is  apparent. 

Now  that  we  understand  the  fun- 
damental dollars-and-cents  feature 
affecting  this  situation,  let  us  ex- 
amine the  causes  of  thunder-storms 
and  lightning  and  find  out  how  and 
why  lightning  rods  afford  protection. 

What  is  it  that  causes  lightning 
and  thunder-storms?  That  is,  how  do 
the  unusual  electrical  conditions, 
which  we  all  know  must  precede  a 
lightning  flash  between  a  cloud  and 
the  earth,  originate?  It  is  almost 
apparent  that  the  cloud  must  be  high- 
ly electrified — must  contain  an  ex- 
cess or  a  deficit  of  electrons  as  com- 
pared with  the  earth  to  cause  the 
lightning  flash.  But  how  does  the 
cloud  thus  become  electrified? 

No  one  can  now  answer  this  ques- 
tion with  absolute  definiteness.  But 
we  can,  thanks  to  the  researches  of 
George  C.  Simpson  of  the  India  Meteoro- 
logical Department,  Simla,  give  a  logical 


By  TERRELL  CROFT 

explanation  which  is  well  supported  by  ex- 
perimental facts.  It  is,  probable,  as  will  be 
shown,  that  the  electrification  of  thunder 
clouds  is  due  to  an  excess  of  electrons  in 
the  cloud  which  electrons  have  been 
knocked  off,  in  the  base  of  the  cloud,  from 
drops  of  water  by  an  ascending  air  current. 

It  appears  that  there  is  always  a  current 
of  moisture-laden  warm  air  ascending  from 
near  the  earth  to  the  cloud  just  prior  to  a 


Cond&cfor  ^ 

Ground 
connect/on  -i=-  6 


Fig.  J 


Experience   Has  Shown  That  the   Ideal    Lightning   Protection   Cage  Suggested   by  Lodge 
Is  Approximated  Amply  if  a  House  Is  Rodded  in  the  Manner  Illustrated. 

thunder  storm. 

When  this  humid  warm  air  current 
reaches  the  cold  region  at  the  cloud,  the 
moisture  in  the  air  current  is  condensed  by 
the  low  temperature  there  and  then  forms 
into  drops  of  water.  The  data  collected 
by  Dr.  Simpson  tends  to  indicate  that  the 
ascending  air  current  then  breaks  into  smal- 


Aer/o/  rerm/no/s  or  Points 


fig.2 


It  Would  Be  Expensive  and  Unsightly  to  Install  a  Com- 
plete Inclosing  Metallic  Cage  on  Every  Building,  Altho 
This  Would  Afford  the  Ideal  Protection  from  Lightning. 


Dr. 


ler  water  particles  or  minute  water  globules 
the  drops  of  water  which  have  been  con- 
densed from  it. 


Now  it  can  be  shown  experimentally  that 
when  "drops  of  distilled  water  which  are 
falling  downward  thru  an  upward  air 
blast  of  sufficient  strength  to  cause  some 
spray,"  the  water  particles  and  the  sur- 
rounding air  become  electrically  charged. 
The  particles  become  positively  electrified 
and  the  surrounding  air  becomes  negatively 
electrified.  In  other  words,  such  an  air 
blast  appears  to  knock  off  some  of  the 
electrons,  which  are, 
as  has  been  explained, 
particles  of  negative 
electricity.  These 
float  about  and  final- 
ly penetrate  to  all 
portions  of  the  cloud, 
charging  the  cloud 
negatively  thruout  its 
entire  volume.  The 
drops  of  water,  from 
which  the  electrons 
were  knocked,  finally 
shift  or  are  forced 
away  from  the  area 
where  they  are  sup- 
ported by  the  ascend- 
ing air  current  and 
ultimately  fall  to  the 
earth  as  rain.  Thus 
the  entire  cloud  be- 
comes negatively  elec- 
trified. 

The  ascending  air 
current   from  the 
earth    to    the  cloud 
must,   in   order  that 
the  electrons  may  be 
torn  off  from  the  con- 
densed-water drops, 
as    above  described, 
have    a    certain  up- 
ward   speed    or  ve- 
locity. And  there  are 
other    conditions  — 
which  it  is  unneces- 
sary to  discuss  here 
— that  must  be  satisfied.    But,  taken  all  to- 
gether,  observation   of    actual  conditions 
leads  Dr.  Simpson  and  others,  who  are  well 
qualified  to  judge,  to  believe  that  the  above 
outlined  theory  explains  in  a  general  way, 
how  thunder-storm  clouds  become  so  high- 
ly electrified. 

Thus  when  a  cloud  has  become  negatively 
electrified,  thru  the  process  above 
outlined,  the  situation  may  then  be 
diagrammed  somewhat  as  shown  in 
Fig.  1.  The  cloud,  C,  contains  many 
or  an  excess  of  free  electrons — is 
highly  electrified  negatively.  The 
area  of  the  earth,  E,  under  the  thun- 
der cloud,  is  in  an  almost  neutral 
state,  that  is,  practically  speaking,  it 
contains  neither  an  excess  or  a  deficit 
of  electrons.  Hence,  there  is  a  ten- 
dency (which  is  sometimes  called  an 
electric  pressure  or  electromotive 
force)  tending  to  establish  an  elec- 
trical balance  between  the  cloud  and 
the  earth.  There  is  a  tendency  for 
the  excess  electrons  in  the  cloud  to 
pass  thru  the  atmosphere  between  the 
cloud  and  the  earth  to  equalize  the 
unbalanced  electrical  condition  due 
to  all  of  those  excess  electrons  in 
the  cloud. 

However,  the  atmosphere  is  a  non- 
conductor of  electricity  or  electrons. 
Hence,  the  excess  free  electrons  on 
the  cloud  cannot  pass  freely  thru 
the  air  to  equalize  the  electrical  un- 
balance. (If  the  air  were  a  good 
electrical  conductor  there  could  be 
no  lightning.)  But  the  tendency  of  the 
electrons  to  pass  to  the  earth  does  create 
a  stress — an  electrostatic  field — in  the  air 


August,  1917 


THE  ELECTRICAL  EXPERIMENTER 


237 


between  the  earth  and  the  cloud.  This 
field  is  represented  in  Fig.  1  by  the  dotted 
lines. 

Now,  as  more  and  more  electrons  are 
knocked  off  of  the  water  drops  by  the  air 
current  ascending  from  the  earth  to  the 
cloud,  the  electrification  of  (the  number 
of  free  electrons  in)  the  cloud  increases. 
The  electrostatic  stress  in  the  air  increases 
correspondingly.  Ultimately,  if  the  separa- 
tion of  the  electrons  from  the  water  drops 
continues,  the  layer  of  air  insulation  be- 
tween the  cloud  and  the  earth  breaks  down 
— it  is  ruptured — and  then  the  free  elec- 
trons in  the  cloud  do 
flow  to  the  earth  and 
the  flow  is  an  electric 
current.  Such  an 
electric  current  thru 
the  air  produces  what 
we  call  lightning,  or 
a  lightning  flash. 

The  "break  down" 
thru  the  air  between 
the  cloud  and  the 
earth  will  occur  at 
the  path  of  least  op- 
position. Usually  the 
path  of  least  opposi- 
tion— the  shortest 
path  electrically  —  is 
between  a  portion  or 
knob  of  the  cloud 
protruding  from  the 
lower  face  of  the 
cloud  and  the  upper 
end  of  some  semi- 
conducting object  ex- 
tending up  from  the 
surface  of  the  earth. 
Thus,  with  conditions 
as  shown  in  Fig.  1, 
the  lightning  flash 
would  probably  occur 
between  A  and  B,  this 
being  the  shortest 
path.  However,  for 
reasons  which  it  is 
unnecessary  to  dis- 
cuss here,  the  short- 
est path  in  feet  be- 
tween the  cloud  and  the  earth  is  not  neces- 
sarily the  one  of  the  least  opposition. 

Thus  we  now  understand  what,  probably, 
causes  lightning  and  why  lightning  usually 
"strikes"  high  objects  extending  from  the 
earth's  surface,  such  as  buildings,  trees, 
towers,  steeples  and  the  like. 

If  there  is  no  lightning-rod  installation 
on  a  building  or  object  and  lightning 
"strikes"  it,  the  lightning-flash  current  will 
flow  thru  some  part  of  the  building  to 
the  earth.  The  current,  which  is  always  of 
enormous  intensity,  may  develop  sufficient 
heat  to  ignite  combustible  objects  in  its 
path.  Thus,  buildings  are  set  on  fire  by 
lightning.  When  the  current  flows  in  a 
non-combustible  material,  it  may  heat  the 
part  of  the  material  in  its  path  to  very 
high  temperature.  Then,  almost  instan- 
taneously, that  moisture  which  has  been 
absorbed  by  the  material  and  which  lies 
in  the  path  of  the  current  is  turned  into 
steam.  An  explosion  results.  It  is  due  to 
these  explosions  that  bricks,  stones  and 
boards  are  knocked  from  buildings  and 
trees  are  splintered  and  split.  Chemical 
action  due  to  the  great  current  may  also 
play  a  part  in  these  "explosions." 

However,  if  a  building  be  surrounded 
by  a  metallic  cage,  as  suggested  in  Fig.  2, 
and  it  is  "struck"  by  lightning,  the  metallic 
conductors  will  offer  a  path  of  such  low 
resistance  (as  compared  with  the  path 
thru  some  poorly-conducting  part  of  the 
building)  that  all  of  the  lightning  flash 
current  will  flow  thru  the  conductors 
to  earth.  Then  no  damage  will  occur,  as- 
suming, of  course,  that  the  conductors  are 
large  enough  so  that  they  will  not  be  melted 


by  the  lightning-flash  current.  We  may 
now  understand  how  lightning  rods  protect 
buildings. 

It  will  be  very  expensive  to  install  a 
complete  inclosing  metallic  cage  like  that 
of  Fig.  2  on  every  building,  altho  such 
a  cage  would  afford  the  ideal  protection. 
Experience  has  shown  that  ample  protec- 
tion is  provided  if  only  part  of  the  cage 
is  installed  on  the  ordinary  building,  as 
shown  in  Fig.  3.  The  conductor  is  so 
routed  over  the  building  as  to  afford  maxi- 
mum enclosure  with  minimum  material. 
Aerial  terminals  or  points  (P,  P  and  P) 


a  long  life  under  conditions  where  iron 
would  rust  away  in  a  short  time.  All  iron 
conductors  should  be  protected  with  a  zine 
coating  to  minimize  corrosion.  A  good  sub- 
stantial iron  conductor  is,  doubtless,  in  most 
cases,  preferable  to  a  flimsy,  weak  copper 
one. 

The  day  of  the  lightning  rod  agent  of  ill 
repute  is  past.  Once,  these  agents  used  to 
ramble  over  the  countryside,  selling  the  un- 
suspecting farmers  anything  from  a  fake 
lightning  rod  to  a  neat  parcel  containing  a 
"million  volts."  But  the  farmer  of  to-day 
is  educated  in  electrical  matters. 


I   \Dmwtfrm  *l//Pe$  or  fonce\  i 

KV  /  I       Mi  1   i  1 


it 


JOINING  GLASS 
AT  MODERATE 
TEMPERATURES. 

In  a  paper  recently 
presented  to  the  Far- 
aday Society,  Messrs. 
Barker  and  Dalladay 
described  some  inter- 
esting experiments  on 
the  direct  joining  of 
glass  at  relatively  low 
temperatures  which 
they  have  carried  out 
in  the  research  labo- 
ratories of  Messrs. 
Adam  Hilger,  Ltd., 
England.  The  results 
described  are  not 
only  of  very  consid- 
arable  direct  scientific 
interest,  but  afford 
great  practical  advan- 
tages in  the  construc- 
tion of  glass  appa- 
ratus out  of  what  is 
actually  a  single  solid 
piece  instead  of  using 
more  or  less  unsatis- 
factory cements.  The 
advantage  of  such 
solid  construction  is 
particularly  evident  in 

Charged  Cloud.    When  This  Stress  Reaches  a_Certain  Limit,  the  Air  Insulator  Is  Broken  polarimeter  tubes  and 
n  Electric  Current  in  the  Forrr 

Have  a  "Lightning"  Discharge.  latter    can  b 


\  \ 
\  \ 


il!!iB  ^w^W^m^ /   I  i 
8iiii.B  .     Iluil,   /    /  I 

■  -/ 
I  I 

/     I  ■ 


Elementary  Representation  of  the  Electrostatic  Stress  Existing  Between  the  Earth  and  a 
Charged  Cloud.    When  This  Stress  Reaches  a  Certain  Limit,  the  Air  Insulator  Is  Broken  t 

Down,  an  Electric  Current  in  the  Form  of  a  Powerful  Spark  (or  Sparks)  Passes,  and  We  absorotion    cells  the 

Thunder  Is  the  Sound  Caused  by  Lightning.   v   , 


are  connected  to  the  top  part  of  the  con- 
ductor system  and  extend  upwardly  into 
the  air.  The  lower  ends  of  the  down  con- 
ductors are  grounded  as  shown  at  G  and  G. 

There  is  not  sufficient  space  available 
here  to  give  complete  directions  for  the 
installation  of  lightning-rods,  because  if  an 
installation  is  to  be  made  most  effectively 
there  are  many  things  must  be  considered. 
In  fact  the  routing  and  arrangement  of 
the  conductor  system  are  the  most  import- 
ant features  of  an  installation.  Good  ma- 
terials can  be  arranged  and  connected  so 
as  to  provide  ineffective  protection.  A  few 
pointers  will  be  given. 

The  lightning  conductor  should  not  be  in- 
sulated from  the  building  and  its  contents. 
First  of  all,  it  is  foolish  to  endeavor  to 
insulate  against  the  enormous  voltages  to 
which  lightning  flashes  are  due.  An  in- 
sulator that  would  actually  insulate  against 
such  voltages  would  be  almost  as  big  as 
a  small-sized  house.  Furthermore,  even  if 
it  were  feasible  to  insulate  the  lightning 
rod  system  from  the  building  and  its  con- 
tents, it  would  be  undesirable  and,  in  some 
instances,  positively  dangerous  to  do  so. 
The  ground  connections  should  be  good. 
The  ground  conductors  should  extend  down 
into  permanently-moist  soil. 

As  to  the  best  metal  for  the  lightning 
conductors  :  Any  reasonably  good  conductor 
will  do,  provided  the  rod  is  large  enough 
so  as  to  be  mechanically  strong  and  so  that 
the  lightning-flash  current  will  not  melt  it. 
Either  iron  or  copper  is  ordinarily  used. 
While  iron — if  big  enough — is  altogether 
satisfactory  as  long  as  it  lasts,  copper  is 
much  more  preferable  because  it  will  have 


can  now 
constructed  with  truly 
parallel  faces  and  with  inside  faces  opti- 
cally worked. 

The  process  of  joining  which  the  au- 
thors have  worked  out  consists  in  plac- 
ing the  surfaces  of  glass  to  be  united  in 
good  optical  contact  under  pressure,  and 
then  raising  the  temperature  to  a  carefully 
determined  degree.  The  glass  surfaces 
thus  treated  become  perfectly  united,  so 
that  the  two  pieces  of  glass  will  not  sep- 
arate along  their  former  interface,  and 
the  composite  piece  acts  as  if  ft  were  a 
single  solid  mass,  even  a  crack  or  a  dia- 
mond-cut will  pass  thru  the  junction  with- 
out hindrance  or  deflection.  The  tem- 
perature employed  is  chosen  as  high  as 
possible  in  order  to  lessen  the  time  re- 
quired for  union  of  the  surfaces,  but  if 
distortion  of  the  optically  worked  surfaces 
is  to  be  avoided,  then  the  temperature  must 
not  be  taken  too  near  the  limit,  which 
the  authors  describe  as  the  "annealing 
point."  This  point  they  determine  by  ob- 
serving the  strains  set  up  in  a  piece  of 
glass  while  being  heated  at  a  definite  rate 
in  an  electric-tube  furnace;  for  each  kind 
of  glass  they  find  that  these  internal 
stresses — which  are  readily  observed  by 
means  of  polarized  light— disappear  quite 
suddenly.  At  this  point,  also,  the  glass 
becomes  appreciably  soft,  and  can  be  in- 
dented by  a  sharp  tool.  When  similar  kinds 
of  glass  are  used,  having  similar  "anneal- 
ing points,"  then  the  welding  of  surfaces 
in  optical  contact  takes  place  well  below 
this  annealing  point.  Very  dissimilar 
glasses,  however,  cannot  well  be  joined, 
since  the  softer  becomes  distorted  before 
the  harder  is  hot  enough  to  weld  freely. 


238 


THE  ELECTRICAL  EXPERIMENTER 


August,  1917 


Women  Radio  Operators  To  Aid  Uncle  Sam 


AMERICAN  women  have  never  yet 
been  found  wanting  when  it  comes 
to  real  dyed-in-the-wool  service, 
no  matter  what  that  service  might 
be — even  to  helping  in  executing 
the  duties  of  war.  The  exigencies  of  war 
have  now  claimed  several  hundreds  of  the 
fair  daughters  of  Cleveland,  Ohio,  where 
a  new  radio  service  school  has  been  in- 


lieved  for  the  service  the  country  needs. 
Railroad  men,  telegraph  and  wireless  op- 
erators have  been  in  great  demand  since 
the  very  inception  of  strife. 

The  classes  are  well  organized  and  hap- 
pily ensconced  in  rooms  where  work  is  con- 
ducted in  a  quiet,  systematic  manner.  The 
Cleveland  Advertising  Club  has  bent  every 
effort  to  make  the  pupils  comfortable,  and 


has  assumed  a  very  live  and  active  concern 
since  the  very  inception  of  the  measure, 
even  sending  Charles  Seldon  of  Baltimore, 
chief  telegrapher  and  head  of  the  main- 
tenance department  of  the  road,  to  Cleve- 
land to  investigate  the  plan  and  offer  the 
assistance  and  co-operation  of  the  road. 
The  company  has  supplied  the  classes  with 
books  on  railroad  rules,  and  has  practically 


Indorsed  By  the  Secretary  of  War  and  Engineered  By  a  Progressive  Cleveland,  Ohio,  Man,  Mr.  Arthur  S.  Newman,  These  Sturdy 
American  Girls  Are  Rapidly  Learning  the  Arts  of  Radio  and  Wire  Telegraphy,  So  As  To  Be  Ready  When  Uncle  Sam  Needs  Them, 


augurated  by  Arthur  S.  Newman,  of  that 
city.  It  has  received  the  unqualified  recom- 
mendation of  Secretary  of  War  Newton 
D.  Baker,  who  says  of  it : 

"This  effort  to  teach  a  number  of  com- 
petent young  women  the  art  of  wireless 
telegraphy  in  order  that  their  services  may 
be  available  to  the  Government  if  needed, 
seems  to  me  a  very  practical  thing  to  do, 
and  it  shows,  too,  the  patriotic  impulse  of 
the  service  and  the  practical  wisdom  of 
choosing  a  way  in  which  services  may  really 
be  demanded." 

The  classes,  which  meet  every  Monday 
evening  at  8  in  the  Cleveland  Advertising 
Club's  rooms,  represent  a  real,  sincere  and 
highly  practical  preparedness  measure  con- 
ceived by  Mr.  Newman,  indorsed  by  Secre- 
tary of  War  Newton  D.  Baker,  and  entered 
into  with  a  zest  that  assures  success  both 
to  instructors  and  students. 

The  idea  back  of  the  instruction  is  the 
training  of  women  to  take  places  of  men 
in  telegraph  and  railroad  service  and  in  the 
wireless  service  on  lake  vessels,  so  that  the 
men  now  holding  those  jobs  may  be  re- 


supplies  every  need  for  efficient  work,  like 
tables  and  blackboards. 

There  have  been  over  one  thousand  ap- 
plicants for  instruction  and  238  of  these 
have  been  accepted.  Among  these  are  law- 
yers, teachers,  physicians,  professional  and 
business  women.  A  very  small  per  cent, 
has  tackled  the  intricacies  of  wireless 
telegraphy — only  about  forty,  in  fact.  Of 
course  the  wireless  operation  presents  more 
complications  which  many  girls  fear  to  un- 
dertake, and,  too,  there  is  a  great  deal  more 
opportunity  for  real  service  in  telegraphy 
than  in  the  wireless. 

"Except  in  case  of  exhaustive  war,"  Mr. 
Newman  stated,  "there  will  be  but  little 
employment  for  women  as  wireless  opera- 
tors, while  railroad  work  and  telegraphy 
offer  an  unlimited  field.  In  case  of  a  long- 
drawn  out  war,  women  would  doubtless  be 
employed  in  the  wireless  service  on  freight- 
ers and  passenger  lake  boats,  but  the  rail- 
roads and  telegraph  companies  can  make 
use  of  efficient  women  right  now." 

Various  railroads  have  evinced  interest 
in  the  classes,  but  the  Baltimore  &  Ohio 


guaranteed  to  place  in  positions  every  girl 
who  is  turned  out  from  the  classes.  The 
railroad  has  further  announced  that  it  is 
not  looking  for  girls  to  take  the  positions 
in  order  to  cut  the  pay  roll,  but  will  place 
them  on  the  same  salary  schedule  it  uses 
for  its  men  employees. 

Telegraphy,  wireless  operating,  railroad 
traffic  and  signaling  will  be  taught  during 
the  course.  The  classes  meet  in  separate 
rooms.  A  part  of  the  two-hour  period  is 
given  to  talks,  and  the  rest  to  practise 
work. 

The  directors  of  the  school  endeavor  to 
bring  speakers  each  Monday  evening,  who 
will  fire  the  patriotism  of  the  students  as 
well  as  give  them  practical  talks  on  the 
subject  matter.  Scientific  demonstrations 
are  also  given,  and  as  the  work  progresses, 
more  complicated  and  technical  programs 
will  be  planned. 

The  girls  •  work  at  three  tables  in  the 
telegraph  room.  Tables  are  equipt  with  in- 
struments, and  each  table  has  its  own  in- 
structor. Miss  Agness  Galagher,  who  has 
{Continued  on  page  270) 


DATE  OF  ISSUE. — As  many  of  our  readers  have  recently  become  unduly  agitated  as  to  when  they  could  obtain  The  Electrical 
Experimenter,  we  wish  to  state  that  the  newsstands  have  the  journal  on  sale  between  the  fifteenth  and  the  eighteenth  of  the  month  in 
the  eastern  part  of  the  United  States  and  about  the  twentieth  of  the  month  west  of  the  Mississippi  River.  Our  subscribers  should  be  in 
possession  of  their  copies  at  these  dates.  Kindly  bear  in  mind,  however,  that  publications  are  not  handled  with  the  same  dispatch  by  the 
Post  Office  as  a  letter.  For  this  reason  delays  are  frequent,  therefore  kindly  be  patient  and  do  not  send  us  complaints  as  to  non-arrival 
of  your  copy  before  the  twenty-fifth  of  the  month. 


August,  1917 


THE  ELECTRICAL  EXPERIMENTER 


239 


ONE  CENT'S  WORTH  OF 
ELECTRICITY. 

At  ten  cents  per  kilowatt  hour  electricity 
will  operate  the  following  for  one  cent: 

A  16-candlepower  Mazda  lamp  for  five 
hours. 

A  six-pound  flatiron  15  minutes. 

A  radiant  toaster  long  enough  to  pro- 
duce ten  slices  of  toast. 

A  sewing  machine  for  two  hours. 

A  fan  12  inches  in  diameter  for  two 
hours. 

An  electric  percolator  long  enough  to 
make  three  cups  of  coffee. 

A  heating  pad  from  two  to  four  hours. 

A  domestic  buffer  for  one  and  one-quar- 
ter hours. 

A  chafing  dish  12  minutes. 

An  electric  broiler  6  minutes. 

An  electric  griddle  8  minutes. 

A  radiant  grill  for  10  minutes. 

An  electric  curling  iron  once  a  day  for 
two  weeks. 

It  will  operate  a  luminous  500-watt  ra- 
diator 12  minutes. 

A  portable  vacuum  cleaner  45  minutes. 

A  sewing  machine  motor  two  and  one- 
half  hours. 

A  vibrator  (for  massage)  four  hours. 

A  washing  machine  for  half  an  hour. 


WIRELESS    PATROL    OF  TRANS- 
MISSION LINES. 

The  Chattanooga  Wireless  Club,  an  ama- 
teur organization  having  wireless  stations 
at  Chattanooga  and  Cleveland,  Tenn.,  ren- 


ELECTRIC  VIBRATORS  HELP 
HEAL  CANADIAN  WOUNDED. 

Surgeons  in  most  of  the  hospitals  car- 
ing for  soldiers  have  found  the  electric 
vibrator  extremely  helpful  in  assisting  the 


"BUY    A    LIBERTY  BOND" 
ELECTRIC  SIGN  BLAZED. 

One  of  the  leading  New  York  electric 
sign  producers  erected  this  sign  for  the 
Government,  free  of  all  cost.  They  also 
maintained  the  sign  free  of  cost  to  Uncle 
Sam  and  paid  the  "juice"  bill.  That's 
what  we  call  real  patriotism !  Let's  have 
more  of  'em.  The  space  is  a  $20,000  one. 
The  original  plan  was  to  erect  an  excep- 
tionally artistic  sign,  but  the  time  was  too 
short,  so  Mr.  Woolley,  the  Director  of 
Publicity  at  the  Treasury  Department, 
suggested  the  design  as  used.  The  phrase, 
"The  Fate  of  Mankind  Lies  in  Your 
Hands"  is  his  thought. 

There  are  3,800  lamps  in  the  sign,  and 
the  structure  is  50  feet  high  and  125  feet 
long. — Photo  courtesy  O.  J.  Gude  Co. 


The  Electric  Vibrator  as  Well  as  the  Treatment  Lamp  Have  Come  Into  Their  Own  for 
Relieving  the  Stiffened  Muscles  and  Wounds  of  Hundreds  of  Canadian  Wounded,  the  Illus- 
tration Showing  These  Devices  in  Use. 


dered  excellent  service  to  the  Tennessee 
Power  Company  on  three  occasions  by  dis- 
covering breaks  in  the  transmission  line. 
The  company  has  used  an  aluminum  line, 
and  when  this  parts,  the  arc  has  made  itself 
heard  at  the  wireless  stations. 


cure  of  returned  soldiers,  suffering  from 
any  form  of  muscular  paralysis.  The  de- 
vices hasten  by  days  the  cure  of  bayonet, 
shrapnel  and  gun  shot  wounds,  as  well 
as  sprains,  strains  and  bruises.  Nerves 
shattered  by  long  hours  under  fire  in  the 
trenches,  sudden  shell-shock,  and  the  re- 
sulting nervous  disorders,  are  all  bene- 
fited by  electric  vibratory  treatment. 

Under  a  doctor's  instruction  the  nurs- 
ing sister  can  use  the  vibrator  on  the 
patient  with  equally  good  results,  and  as 
the  patient  improves  he  himself  can  as- 
sist his  cure.  This  treatment  is  said  to 
energize  and  vitalize,  besides  purging  the 
blood  of  toxic  poisons — soothing  the 
nerves  and  giving  complete  relaxation 
more  restful  than  sleep. 

The  illustration  shows  a  special  vibra- 
tor, as  well  as  a  thermolite  treatment  lamp 
in  actual  use  in  one  of  the  Canadian  con- 
valescent homes. 

The  thermolite,  whose  healing  proper- 
ties are  produced  by  a  combination  of 
light  and  heat,  is  highly  recommended  for 
nervous  complaints. 


These  Electric  Signs  "Buy  a  Liberty  Bond"  and  "Enlist  in  the  Navy"  Were  Erected  and 
Maintained  in  New  York  City  Free  of  All  Cost  to  Uncle  Sam  by  a  Patriotic  Concern  in 

That  City. 


CITY    SELLS    LIGHTING  POSTS 
FOR  MUNITION  USE. 

The  Street  Department,  Bronx,  N.  Y., 
has  arranged  for  the  sale  of  about  6,000 
old  lamp-posts  used  for  gas  service,  and 
now  superseded  by  an  electric  street-light- 
ing system,  to  R.  D.  Wood  &  Company, 
Philadelphia,  Pa.,  at  a  cost  of  $1.06  each, 
with  removal  by  the  purchaser.  Prior  to 
the  country's  entrance  into  the  war  the 
borough  had  been  paying  about  $11  each 
to  have  the  posts  removed  by  private  con- 
tractors, bringing  a  considerable  asset 
where  a  financial  burden  was  anticipated. 
It  is  said  that  the  posts  will  be  utilized  in 
shrapnel  manufacture. 


240 


THE  ELECTRICAL  EXPERIMENTER 


August,  1917 


An  Electrical  Miniature  Village  de  Luxe 


WE  were  all  kids  once,  to  be  sure, 
but  it  is  doubtful  if  any  of  us  ever 
had  such  a  wonderful  play-thing 
as  two  little  Chicago  boys,  George 
and  Robert,  the  twin  sons  of  Mr. 
and  Mrs.  Robert  Hutchison,  who  have  an 
electric  village  that  might  very  well  typify 
in  miniature  the  great  electrical  city  of  Chi- 


will  be  seen  the  house,  the  garage,  the 
opera  house,  the  stores  and  the  church. 
The  residence  is  on  a  grassy  knoll  with 
lawn  and  path  neatly  laid  out,  and  the 
railroad  line  finds  it  necessary  to  pass  thru 
a  long  tunnel  underneath  this  part  of  the 
scene.  The  street  railway,  on  the  other 
hand,  makes  a  loop  over  a  pretty  rustic 


purchased  as  oil  lamps  and  have  been  made 
over  by  Mr.  Hutchison.  All  motors  have 
been  rewound  to  accommodate  themselves 
to  the  voltages  derivable  by  the  use  of  a 
150-watt  step-down  toy  transformer  and 
the  alternating  current  lighting  circuit. 
The  smaller  illustration  herewith  shows 
the  neat  400-watt  electric  plant,  compris- 


How  Would  You  Like  to  Be  the  Boy  Who  Owns  This  Wonderful  Electric  Village — Where  the  Trains  Whiz  by  the  Crossings,  the  Wind- 
mill Turns,  the  Church  Chimes  Ring,  and  Even  the  Opera-house  Electric  Sign  Flashes  On  and  Off?  Two  Chicago  Boys  Are  the  Happy 
Owners  and  We'll   Bet  Dollars  to  Doughnuts  They  Will  Grow  Up  to  Be  Future  Edisons.    Such  a  Display  Is   Nothing   If  Not  Highly 

Educating  and  inspiring. 


cago  in  which  they  live.  The  photograph 
cannot,  of  course,  show  the  movement  of 
the  miniature  railroad  train,  operated  by 
electricity;  nor  the  speeding  third-rail  in- 
terurban  electric  car ;  the  whirling  windmill 
pump  ;  the  twinkling  of  the  electric  stars  in 
the  little  blue  firmament  provided ;  the 
tolling  of  the  church  bell  and  the  music  of 
the  organ;  the  man  cranking  the  automobile 
at  the  entrance  to  the  garage,  and  the  flash- 
ing of  the  sign  on  the  opera  house.  These 
things  the  camera  must  show  as  tho  they 
moved  not ;  but  when  the  village  is  in  oper- 
ation they  all  do  move  and,  in  addition, 
the  pretty  little  electric  fountain  throws 
its  spray  nearly  a  foot  into  the  air,  the 
electric  street  lamps  glow,  the  store,  resi- 
dence and  church  windows  shed  a  pretty 
light,  and  the  safety  gate  at  the  railroad 
crossing,  just  where  the  big  engine  is  stand- 
ing in  the  photograph,  falls  and  rises  with 
precision  on  the  approach  of  the  train  and 
when  it  has  past. 

All  of  these  things  are  arranged 
with  beautiful  mechanical  perfection 
of  finish  and  detail.  The  base  is  fif- 
teen feet  long  and  six  feet  wide. 
The  motive  power  for  everything 
is  electrical,  there  being  nine  sepa- 
rate small  electric  motors  in  differ- 
ent parts  of  the  foundation  of  the 
electric  village.  There  are  no  less 
than  42  miniature  electric  lamps, 
counting  headlights  on  the  trains 
and  other  small  lights. 

With  the  aid  of  an  able  assistant 
whose  artistic  work  with  the  brush 
appears  in  the  decorative  part  of  the 
work,  Mr.  Hutchison,  who  made 
nearly  every  detail  himself,  has 
worked  out  these  things  and  many 
more,  with  a  careful  regard  for  rela- 
tive sizes ;  thus,  the  farmer  stand- 
ing in  the  barnyard,  and  the  horse 
and  other  live  stock  nearby,  are  rel- 
atively of  about  correct  proportions  ; 
so  are  the  other  people  on  the  street 
and  on  the  porch  of  the  house,  and 
so  are  the  buildings  and  the  imple- 
ments and  accessories  which  go  to 
make  up  the  completeness  of  social 
and  commercial  activity  in  this  model  vil- 
lage. 

The  village  main  street  begins  just  to 
the  right  of  the  residence,  and  along  it 


bridge  and  around  the  park  with  the  little 
pond  and  the  ducks  at  the  right-hand  end 
in  the  foreground,  passing  back  to  an- 
other loop  at  the  left  hand  and  return- 
ing. An  interesting  feature  of  this  street 
railroad  is  the  automatic  switches  connect- 
ing the  main  track  with  the  loop  at  each 
end  and  operated  by  the  flange  of  the  rear 
wheels  of  the  car  as  it  passes  over  them, 
so  that  the  next  time  the  car  approaches 
the  loop  it  will  pass  round  it  in  the  oppo- 
site direction,  varying  the  effect. 

The  electric  fountain  used  to  be  sup- 
plied from  the  water  tower,  the  pump  feed- 
ing the  latter ;  but  this  has  been  super- 
seded by  a  direct  feed  from  the  pump  to 
the  fountain,  a  metal  diafram  and  air 
chamber  equalizing  the  pressure. 

So  particular  has  Mr.  Hutchison  been 
about  the  construction  of  his  electrical 
features,  that  there  are  certain  lamps  in 
this  installation  which  were  made  espe- 
cially for  him.    These  little  incandescent 


ing  a  dynamo  driven  by  a  gasoline  engine. 
A  suitable  switchboard  is  installed  so  that 
service  may  be  taken  from  the  electric 
light  company's  mains  or  from  the  isolated 
plant  here  pictured. 

A  very  neat  asbestos  board  switchboard 
on  the  wall  near  by  has  switches  for  all 
the  principal  divisions  of  the  exhibit,  in- 
cluding the  street  lighting,  the  street  car, 
the  railroad  train,  fountain,  windmill, 
graphophone,  church  chimes,  sign  flasher, 
star  flasher,  store  lights,  automobile,  cross- 
ing gates,  etc. 

It  is  quite  interesting  to  see  the  two 
little  boys  manipulate  these  switches  with 
the  utmost  quickness  and  precision  to  ex- 
hibit the  various  effects  of  which  they 
are  so  fond. 

Mr.  Hutchison  sets  up  this  electric  vil- 
lage in  the  basement  of  his  residence  each 
Christmas  time,  and  for  the  last  five  years 
it  has  been  growing  to  its  present  propor- 
tions. 


LIABILITY  TO  TRESPASS- 
ERS ON  POLES. 

An  employee  of  a  telephone  com- 
pany went  on  the  pole  of  a  power 
company  in  the  absence  of  any  con- 
tract or  agreement  giving  the  em- 
ployee or  the  telephone  company 
the  right  to  do  so.  He  was  injured 
by  an  electric  shock  received  thru 
a  defect  in  a  transformer.  In  an 
action  against  the  power  company 
it  was  held  that  both  the  telephone 
company  and  its  employee  were 
trespassers  on  the  power  company's 
pole,  and  the  power  company  was 
not  liable  for  the  injury.  The  estab- 
lisht  principle  in  the  law  of  negli- 
gence, that  there  is  no  liability  to 
trespassers  except  for  injuries  wil- 
fully or  wantonly  inflicted,  is  appli- 
cable to  electric  companies  and 
electric  appliances. 


The 

Plant 


Complete   Independent   400- Watt    Electric  Generating 
Which  Is  Available  for  Supplying  the  Miniature  City 
Shown  Above  with  the  Necessary  Current. 


bulbs  have  flat  sides  like  very  short  bung- 
hole  lamps  of  miniature  type,  and  were 
made  to  accommodate  themselves  to  the 
little  electric  lanterns  which  were  originally 


A  wireless  plant  fully  equipt  and 
capable  of  sending  messages  5,000 
miles,  was  discovered  by  govern- 
ment Secret  Service  officials  near 
the  base  of  Mount  Hood  in  the  Cascade 
Mountains  of  Oregon  recently.  Evidently 
the  proposed  raid  had  become  known,  the 
plant  being  abandoned. 


August,  1917 


THE  ELECTRICAL  EXPERIMENTER 


241 


The  Capitol   at   Washington,    D.  C. 

Triumph 


BEAUTIFUL    ILLUMINATION  OF 
CAPITOL  AT  WASHINGTON. 

Against  the  sombre  shadows  of  night, 
at  this  critical  moment  in  our  history,  the 
inspiring  white  dome 
of  our  Capitol  at 
Washington,  high 
above  the  Federal 
City,  stands  resplen- 
dent in  rays  of  shin- 
ing light,  a  radiant 
monument  to  free- 
dom and  democracy. 
The  plans  for  illu- 
minating the  Capitol 
dome  were  perfected 
for  the  recent  in- 
auguration of  Presi- 
dent Wilson,  and  the 
spectacular  results 
were  so  satisfactory 
that  the  system  was 
made  permanent. 

Flood  lighting  was 
the  method  used  to 
illuminate  the  great 
dome,  which  is  135 
feet  in  diameter  at 
the  base,  218  feet 
high  above  the  roof, 
and  is  surmounted 
by  a  bronze  statue 
of  Freedom.  Eighty- 
f  o  u  r  flood  proj  ec- 
tors,  each  e  q  u  i  p  t 
with  a  400-watt  flood 
lighting  lamp,  were 
used.  These  pro- 
jectors were  placed 
in  four  banks,  about 
200  feet  from  the  dome,  on  the  corners 
of  the  House  and  Senate  wings.    By  plac- 

A  REAL  "WAR"  LAMP  MADE 
FROM  SHELLS. 

An  Ohio  concern  is  now  offering  a 
special  lighting  unit  which  is  known  as 
the  "War  Lamp."  This  remarkable  and 
appropriate  (sic  pac- 
ifists) lamp  is  shown 
in  the  accompanying 
illustration  and  is 
made  from  genuine 
shrapnel  shells,  3-in. 
Russian  and  British, 
called  "18-pounders" 
or  the  French  "75 
mm."  The  total 
height  is  23  in.  and 
the  base  Sy2  in.,  with 
the  bullet  globe  3  in. 
The  base  support 
uses  nickel  shrapnel 
balls.  Lamps  up  to 
75-watts  can  be  used 
in  the  unit.  This 
lamp  is  intended  as 
a  reading  lamp  for 
homes,  offices  or 
stores  and  is  a  prac- 
tical unit,  besides  be- 
ing a  souvenir  of 
historical  value  later. 
A  5  in.  by  8  in.  silk 
flag  eye  shade  and 
a  suitable  holder  for 
it  is  furnished  with 
each  lamp  and  adds 
a  patriotic  touch, 
The  makers  guaran- 
tee each  shell  to  be 
genuine. 


ing  the  projectors  in  these  positions,  it 
was  found  possible  to  throw  light  from 
different  directions  on  the  36  columns  at 
the  base  (representing  the  36  states  in  the 


service.  At  the  end  of  1914  there  was  a 
total  of  1,940  stations  supplying  electricity, 
390  of  these  being  central  stations,  24  rail- 
way plant,  47  combined  railway  and 
central  station  plant, 
1,366  isolated  plants, 
and  the  remainder 
official  installations. 
The  water-power 
stations  number 
695,  steam  788  and 
gas-driven  stations 
547.  The  total  ca- 
pacity of  these  sta- 
tions is  608,544  kw., 
of  which  341,809  kw. 
are  central  stations, 
140,000  isolated 
plants.  The  water- 
power  equipment 
totalled  366,243  kw., 
steam  217,967  kw., 
and  gas  stations  24,- 
344  kw.  There  were 
21,909  miles  of  aerial 
and  751  miles  of  un- 
derground transmis- 
sion lines. 


at  Night  with  Its  New  Electric  Flood  Lighting — a 
n   Illumination  Engineering. 


Union  at  the  time  it  was  designed),  and 
thus  eliminate  objectionable  shadows.  Some 
shadows  are  desirable  to  bring  out  the 
architectural  beauty,  but  if  the  shadows 
are  too  pronounced  they  become  objection- 
able. 

The  building  proper  was  also  lighted 
to  a  low  intensity,  to  form  a  setting  for 
the  dome  and  to  relieve  the  contrast  be- 
tween a  very  light  dome  and  a  dark  build- 
ing. The  building  is  about  750 
feet  long  and  250  feet  wide. 
The  central  portion,  or  main 
building,  is  of  sandstone  paint- 
ed white,  and  the  House  and 
Senate  wings  at  the  ends  are 
of  white  marble.  Surrounding 
the  building  on  three  sides  is  a 
wide  concourse  bounded  by  a 
parapet.  Thirty-four  flood 
lighting  projectors,  each  equipt 
with  a  400-watt  flood  lighting 
lamp,  were  mounted  on  orna- 
mental posts  and  placed  on  this 
parapet.  The  poles  were  orig- 
inally designed  to  take  large 
opal  globes.  These  globes  were 
removed  and  blocks  of  wood 
were  placed  in  the  fittings,  to 
which  the  projectors  were  bolt- 
ed. Thus  the  projectors  were 
inconspicuous  and  did  not  de- 
tract from  the  natural  archi- 
tectural features  around  the 
building.    Photo.  G.  E.  Co. 


METAL  HEAT- 
ING PAD. 

A  western  manu- 
facturer has  placed 
on  the  market,  after 
thoro  testing,  a 
metal  heating  pad. 
This  hot-pad  con- 
sists of  a  heating 
element  encased  in  a 
nickeled  steel  jacket 
made  up  of  hinged  units  permitting  the 
bending  of  the  inner  heating  element.  The 
flexibility  is  sufficient  for  the  requirements 
demanded  of  a  hot-pad  as  the  illustration 
shows ;  it  may  even  be  wrapt  around  a  limb. 

It  operates  from  any  lamp-socket,  con- 
sumes 40  watts  and  its  heat  is  easily  regu- 
lated, even  in  the  dark  or  under  the  bed- 
cover, by  a  small  lever.  Any  temperature 
from   100  to  200   degrees   Fahrenheit  is 


The  Electric  Metal  Heating  Pad  Here  Illustrated  Is  Ex- 
cellent for  That  Stiff  Neck,  Ear-ache,  or  Neuralgia.  It 
Connects  with  Any  Lamp  Socket. 


To  Be  Up  to  Date  You  Must  Have  One  of 
These  Electric  Table  Lamps  Made  from  Gen- 
uine 75  mm.  Shells. 


ELECTRIC  PROGRESS  IN  JAPAN. 

Japan  is  taking  to  electricity  like  a  duck 
to  water.  The  Lake  Inawashiro  plant  now 
includes  six  10,000  h.p.  turbines,  and  trans- 
mits power  at  a  pressure  of  115,000  volts 
over  140  miles  of  transmission  lines  in 
Tokio.  This  is  one  of  the  big  hydro-elec- 
tric schemes  which  Japan  has  now  put  in 


easily  attained  and  automatically  main- 
tained by  thermostat ;  it  cannot  become  over- 
heated, as  current  is  shut  Off  automatically 
when  certain  temperature  is  reached. 
Under  average  conditions,  it  may  be  oper- 
ated at  least  five  hours  for  less  than  one 
cent's  worth  of  current.  It  is  provided 
with  soft,  washable  and  removable  eider- 
down cover  and  encased  in  "parchmyn" 
envelop.  It  comes  complete  with,  cord 
and  connection  plug,  ready  for  use. 


242 


THE  ELECTRICAL  EXPERIMENTER 


August,  1917 


LET  THE  ELECTRIC 
REFRIGERATOR  KEEP  YOUR 
FOOD. 

The  electric  refrigerator  illustrated  com- 
prises a  motor-driven  ice-machine  adopted 
to  any  standard  refrigerator,  the  ice  ma- 


Using  Ethyl-Chlorid  as  the  Refrigerant, 
This  Electrically  Operated  Refrigerator 
Automatically  Keeps  the  Food  Compartments 
at  Frigid  Temperature.  Besides,  it  Freezes 
Ice  Cubes  for  Table  and  Kitchen  Use. 


chine  itself  occupying  what  would  ordi- 
narily be  the  ice-box.  Here  we  have  the 
cooling  coils,  partly  immersed  in  a  brine 
tank  containing  receptacles  in  which  small 
blocks  of  pure  ice  are  formed  for  table  use. 
This  electric  refrigerator  is  claimed  to  be 
entirely  safe.  Explosions  in  large  refrig- 
erating plants  are  due  to  the  use  of  ammo- 
nia gas  under  pressure.  To  avoid  possible 
danger  from  this  source  in  the  household 
refrigerator,  ethyl  chlorid  at  low  pressure 
has  been  substituted  for  ammonia. 

This  type  of  electric  refrigerator  is  auto- 
matic. It  is  regulated  to  maintain  a  con- 
stant temperature,  the  machine  starting  and 
stopping  automatically,  by  means  of  an  in- 
genious thermostatic  control.  All  valves 
are  locked:  the  consumer  is  not  called  up- 
on to  make  any  adjustment,  and  the  ma- 
chine will  run  from  one  to  three  years  with- 
out adjustment. 

Artificial  refrigeration  by  such  a  machine 
is  said  to  be  much  cheaper  than  ice.  About 
two  and  one-half  kilowatt  hours  of  current 
are  required  for  one  hundred  pounds  of 
ice-effect  in  the  course  of  one  day.  At  the 
eight-cent  rate  for  current,  this  makes  the 
cost  of  refrigeration  twenty  cents  for  the 
ice-effect  of  one  hundred  pounds,  as  con- 
trasted with  real  ice  at  forty  cents  a  hun- 
dred. In  suburban  and  country  districts 
the  contrast  is  still  more  marked  for  the 
price  of  ice  there  more  frequently  runs  up 
to  sixty  and  seventy  cents  a  hundred,  and 
in  addition  the  ordinary  ice  supply  is 
usually  irregular  and  inadequate. 


Automatic  control  cuts  down  the  amount 
of  electricity  used,  for  when  the  set  tem- 
perature is  reached  the  motor  is  automati- 
cally cut  off.  Thus  the  machine  consumes 
current  only  when  actually  in  operation, 
and  this  is  but  a  small  proportion  of  the 
twenty-four  hours.  The  entire  machine 
can  be  operated  from  an  ordinary  lamp- 
socket,  this  being  another  indication  of  the 
small  amount  of  power  required. 

With  an  electric  ice  machine,  the  purity 
of  the  table-ice  can  be  absolutely  guaran- 
teed, each  family  using  whichever  distilled 
water  it  prefers  for  this  purpose.  Table 
ice  is  frozen  in  about  two  hours'  time. 
Furthermore,  with  artificial  cooling  substi- 
tuted for  melting  ice,  the  refrigerator  can 
be  kept  strictly  clean  with  little  effort,  thus 
preventing  contamination  of  food. 

The  household  refrigerator  comes  in 
three  sizes ;  the  smallest  is  rated  to  give  the 
cooling  effect  of  one  hundred  and  fifty 
pounds  of  ice;  the  second  size,  three  hun- 
dred pounds ;  and  the  largest,  six  hundred 
pounds. 

The  machine  is  regulated  to  preserve  cer- 
tain temperatures  thruout  the  refrigerator. 
In  the  upper  left-hand  compartment,  where 
table-ice  is  made,  the  temperature  is  twen- 
ty-four degrees  Fahrenheit.  The  section 
below  it  is  kept  at  thirty-eight  degrees,  the 
lower  right-hand  compartment  at  forty- 
two  degrees,  and  the  upper  right  hand  at 
forty-six  degrees.  These  variations  pro- 
vide for  proper  circulation  of  air  within  the 
refrigerator,  thus  keeping  it  dry  and  sweet. 
They  are  also  desirable,  as  foods  require 
different  temperatures  for  best  results  in 
their  preservation.  Thus,  milk,  butter  and 
eggs  would  be  placed  in  the  lower  left- 
hand  compartment:  cooked  foods  and 
meats  in  the  lower  right-hand  chamber ; 
and  fruits  and  vegetables,  requiring  a  less 
degree  of  cold,  in  the  upper  right-hand 
chamber. 

The  refrigerant,  ethyl-chlorid,  is  a  neu- 
tral gas  which  in  the  manner  employed  does 
not  change  or  deteriorate  with  use,  neither 
does  it  act  on  the  metals  of  which  the  ma- 
chine is  constructed. 
The  process  employed 
is  known  as  the  com- 
pression system  :  the 
gas  is  expanded  from 
a  liquid  state  at  a  rel- 
atively high  pressure 
to  a  gaseous  state  at  a 
lower  pressure,  corre- 
sponding to  the  tem- 
perature  required. 
This  gas  is  withdrawn 
from  the  cooling  coils 
and  discharged  into 
the  condensing  cham- 
ber by  means  of  a 
specially  designed  ro- 
tary compressor, 
where,  by  the  com- 
bined action  of  pres- 
sure and  cooling  by 
water  pas-sing  thru  the 
condenser  coil,  the 
latent  heat  of  vapori- 
zation is  removed, 
and  the  gas  condensed 
to  liquid  again,  ready 
once  more  for  the  re- 
frigerating  cycle. 
Water  consumption  is 
at  the  rate  of  about 
fifteen  gallons  per 
hour  while  the  ma- 
chine is  running,  the 
flow  being  shut  off 
when  the  machine  is 
stopt. 


FLASHLIGHTS  AS  CHEAP  AS 
MATCHES. 

It  costs  no  more  to  operate  an  electric 
flashlight  than  to  use  matches  for  the  same 
purpose,  according  to  figures  compiled  re- 
cently. Each  modern  tungsten  battery  (for 
flashlight  use)  is  guaranteed  to  burn  for 
a  certain  number  of  hours,  and,  using  this 
guarantee  as  a  basis,  it  is  found  that  the 
average  cost  of  operating  such  a  flashlight 
is  one  cent  for  600  flashes,  of  a  second 
each,  or  for  60  flashes  of  10  seconds  each. 

Now,  the  average  one-cent  box  of 
matches  contains  just  60  matches.  Each 
of  these  will  burn  for  15  seconds,  but  when 
allowance  is  made  for  some  blowing  out 
and  others  being  used  for  a  second  or  two 
only,  it  is  estimated  that  the  average  match 
does  not  burn  longer  than  10  seconds.  At 
this  figure  the  cost  would  be  the  same  as 
that  of  using  a  flashlight. 

Some  of  the  most  popular  styles  of  flash- 
lights, however,  cost  a  good  deal  less  than 
this  to  operate.  Take  for  instance,  the 
tubular  pocket  flashlight,  in  which  the  bat- 
tery gives  1,200  flashes  of  a  second  each 
for  one  cent.  This  size  battery  costs  one- 
half  as  much  to  use  as  would  safety  matches. 


AN  ELECTRIC  TABLE  LAMP  THAT 
SPEAKS. 

The  combination  phonograph  and  electric 
lamp  shown  in  the  accompanying  illustra- 
tion has  been  developed  by  a  New  York 
inventor.  The  phonograph  is  concealed  in 
the  base  of  the  lamp,  which  is  so  designed 
that  it  will  accommodate  any  size  records  up 
to  the  12-in.  disk.  When  the  phonograph 
is  to  be  played  the  hood  is  raised,  the  disk 
inserted  and  the  power  turned  on. 

The  disk  is  revolved  by  a  small  motor  in 
the  same  circuit  as  the  electric  light,  but 
controlled  by  a  separate  switch.  This  ar- 
rangement makes  it  possible  to  play  the 
instrument  when  the  lamp  is  not  in  use.  In- 
stead of  using  a  horn  as  with  some  "talk- 
ing" machines,  the  sound  is  diffused  thru 
the  stem  of  the  lamp,  which,  it  is  claimed, 
considerably  softens  the  tone.   The  "phono- 


Behold!    the    Electric   Table    Lamp   That   Speaks   and    Sings — 
Thanks  to  a  Phonograph  Cleverly  Concealed  in  the  Base  and 
Driven    by   a    Miniature    Electric  Motor. 


Mine  gas  is  detected  with  a  portable 
electric  outfit  which  miners  carry. 


lite,"  as  this  combination  set  is  called,  is 
especially  applicable  where  there  is  a  limited 
amount  of  room  as  in  small  apartments. 


August,  1917 


THE  ELECTRICAL  EXPERIMENTER 


243 


ELECTRICAL  CITY  GUIDE  TELLS 
WHERE  YOU'RE  AT. 

By  D.  Wyman. 

A  novel  device,  the  Electric  Directory, 
has  been   installed   by   several  prominent 


How  Do  I  Get  to  125  Street  and  Seventh  Avenue?  That 
and  Hundreds  of  Similar  Ones  Are  Now  Answered  by  the 
Electric  Street  Guide,  Here  Shown  Installed  in  the  Hotel 
Martha  Washington,  New  York  City. 

New  York  City  Hotels  and  will  soon  be 
seen  all  over  the  United  States. 

The  apparatus  serves  the  dual  purpose 
of  an  accurate  street  guide  and  attractive 
sign  board.  It  is  of  pleasing  appearance, 
about  sixteen  square  feet  in  size  and  has 
an  all-glass  and  mirror  front.  In  its  center 
is  a  large  map  of  New  York  City  with 
a  number  of  interchangeable  advertising 
spaces  arranged  alongside  of  it.  Below 
the  map  are  two  boards,  each  mounted  with 
thirty  numbered  push  buttons.  In  a  pocket 
between  the  push  button  boards  is  an  Index 
Book,  wherein  every  point  shown  on  the 
map  is  alphabetically  listed,  with  a  number 
placed  opposite  each  of  them.  All  a  per- 
son has  to  do  to  operate  the  guide  is  to 
press  the  button  bearing  the  number  of  the 
place  sought;  railroad  station,  part  of  street 


or  avenue,  etc.,  whereupon  a  bright  light 
appears  on  the  map  giving  the  desired 
location,  while  a  red  light  indicates  the 
hotel  as  the  starting  point.  The  pressure 
of  any  button  automatically  flashes  up  all 
the  advertisements,  which  together  with  the 
map  are,  however,  visible  and 
readable  even  when  not  illumi- 
nated. 

Fifty  4-volt  lamps  are  evenly 
distributed  behind  the  adver- 
tising spaces.  The  current  is 
supplied  by  a  special  type  of 
storage  battery.  The  pressure 
of  any  button  closes  the  circuit 
to  one  map  light  and  to  the 
starting  point  indicator,  auto- 
matically operating  a  relay 
which  closes  the  second  circuit 
for  the  fifty  advertising  lights. 

TEACHING  WAR  AT 
COLUMBIA. 

Columbia  University's  enrol- 
ment in  the  special  war  courses 
which  opened  some  time  ago 
has  exceeded  all  expectations. 
The  work  is  in  charge  of  Prof. 
Tames  C.  Egbert,  director  of  the 
department  of  ex- 
tension teaching. 
Prof.  Egbert  has 
decided  to  permit 
students  to  enter 
the  classes  for  sev- 
eral  more  weeks. 

The  courses  in- 
clude   training  in 
trench  construc- 
tion, camp  sanita- 
tion, army  regula- 
tions,  radio 
telegraphy  and  en- 
gineering training 
such  as  is  needed 
by  army  engineers 
and  for  similar 
courses. 
Other  courses  are  offered  for 
governmental  training,  and  hosts 
of  classes  are  open  for  special 
training  for  women  who  desire 
to  be  of  service  to  the  Gov- 


AT  LAST  A  VERTICAL  COMPASS. 

Navigators  on  the  Sea  or  in  the  Air 
can  now  ascertain  their  direction  from  a 
compass  whose  dial  is  vertical.  This  is  es- 
pecially convenient  because  it  makes  pos- 
sible the  reading  of  a  compass  set  on  a 
level  with  the  eyes  and  does  away  with 
the  necessity  of  bending  forward  and  over 
the  compass.  At  the  same  time  the  ver- 
tical compass  on  aeroplanes  can  be  mounted 
a  greater  distance  from  the  disturbing  ele- 
ments, such  as  control  cables,  etc. 

This  new  compass  was  invented  by  Cap- 
tain F.  O.  Creagh-Osborne,  Superintendent 
of  Compasses  for  the  British  Admiralty. 
It  is  now  manufactured  for  the  United 
States  Air  Service  by  Elmer  A.  Sperry, 
member  of  the  Naval  Consulting  Board, 
and  inventor  of  the  gyro-compass  now 
used  in  American  and  other  first-class 
navies  thruout  the  world. 

This  new  instrument  is  a  magnetic  com- 
pass, having  the  card  mounted  in  a  liquid 
in  order  to  minimize  oscillation  and  to 
help  support  it.  The  compass  card  really 
is  a  narrow   strip  of  metal  mounted  on 


Always,  fo 
on  a  Com 
Th 


HOW   TELEPHONE   AIDS  STAGE 
LIGHTING  DESIGN. 

The  great  motion  pictures  of  the  day 
are  practically  all  directed  by  means  of  the 


The  Telephone  Has  Found  Another  Role  in  Helping  the  Experts 
to  Design  Theatrical  Illumination  Effects. 


ernment  during  the  war. 

telephone,  but  the  telephone  is 
used  not  only  for  directing 
motion  picture  scenes,  but  also 
as  a  modern  aid  in  securing 
desired  lighting  effects  in  con- 
nection with  the  staging  of 
scenes  in  a  theater  catering  to 
legitimate  drama. 

An  expert  in  lighting  effects  equipt  with 
an  operator's  set  occupies  a  seat  in  the 
audience  and  transmits  instructions  to  the 
stage  electrician  also  equipt  with  an  oper- 
ator's set,  who  is  stationed  at  the  electric 
light  switchboard,  which  is  located  on  one 
side  of  the  stage.  By  using  the  telephone, 
the  most  perfect  lighting  arrangements  can 
be  obtained  and  proper  adjustments  made 
at  the  instant  under 
expert  direction  with- 
out the  noise  of  bells, 
buzzers  or  other  sig- 
nals, as  the  telephone 
line  is  in  constant  use 
thruout  the  perform- 
ance. 

The  stage  electrician 
is  sp  located  that  it 
is  impossible  for  him 
to  see  the  lighting  ef- 
fect as  it  is  seen  by 
the  audience.  The 
telephone  has  again 
solved  a  problem  and 
has  accomplisht  the 
desired  results  with 
success. — T.  R. 


r  Centuries,  Mariners  Have  Had  to  Look  Down 
pass.  Now  They  May  Look  Straight  Ahead, 
anks  to  the  "Sperry"  Vertical  Compass. 

the  float.  The  points  of  the  compass  are 
indicated  on  the  card  with  a  radium  com- 
pound so  they  will  be  visible  at  night.  The 
bowl  of  the  compass  is  like  a  metal  sphere 
having  a  circular  window  on  its  surface. 

This  bowl  is  mounted  so  that  the  vibra- 
tions are  not  transferred  by  the  frame  to 
the  card.  Gimbal  rings  are  entirely  dis- 
pensed with  and,  at  the  same  time,  a  gen- 
erous heeling  angle  is  obtained.  Neither 
reflecting  nor  refracting  devices  are  neces- 
sary, the  compass  being  read  directly. 
Compensating  magnets  are  provided  in  the 
small  container  attached  separately  to  the 
frame. 


ELECTRIC  AUTOS   IN  MADRID. 

It  is  considered  probable  that  there  will 
shortly  be  a  good  opportunity  for  push- 
ing the  sale  of  electric  vehicles  in  Madrid, 
as  the  cobble  pavements  of  the  city  must 
be  replaced  by  asphalt  or  other  similar 
surface  within  two  years. 

The  ordinary  animal-drawn  carts  and 
heavy  wagons  are  injurious  to  asphalt 
pavements,  and  it  should  not  be  difficult 
to  get  a  footing  for  the  smooth-running 
and   reliable   electrically-propelled  vehicle. 


244 


THE  ELECTRICAL  EXPERIMENTER 


August,  1917 


UNIQUE  PORTABLE  ELECTRIC 
PLANT. 

The  accompanying  photograph  shows  a 
portable  electric  generating  outfit  which 
has  been  manufactured  especially  for  the 
use  of  the  American  Telephone  and  Tele- 


J 


Extremely  Compact  and   Efficient  Portable   Engine  and  Dynamo 
Set  for  Supplying  Current  to  Electric  Hammers  and  Drills,  One 
of  Which  Is  Here  Shown  In  Use. 


graph  Company,  in  building  the  Jackson- 
ville-Key West  toll  line  along  the  concrete 
causeways  of  the  Florida  East  Coast  Rail- 
way. The  set  consists  of  a  \Yi  h.p.  gaso- 
line engine,  belted  to  a  120  volt  30  ampere 
generator.  The  wiring  on  the  power  board 
admits  of  attaching  three  leads  which  are 
used  for  the  electric  drills  and  electric 
hammers,  one  of  the  latter  being  shown 
in  the  position  in  which  it  will  be  used. 
The  weight  of  the  entire  outfit  is  not  great, 
four  men  being  able  to  handle  it  easily. 
— Photo  courtesy  Western  Electric  Co. 


MAGNET  RESET  FOR  MAXIMUM 
AND  MINIMUM  REGISTERING 
THERMOMETER. 

The  thermometer  shown  in  the  illustra- 
tion below  is  set  by  drawing  the  bottom  of 
the  index  in  each  side  of  the  tube  down  to 
the  mercury  column,  with  the  magnet. 

As  the  temperature  fluc- 
tuates the  mercury  will  rise 
in  one  side  or  the  other, 
leaving  the  index  in  either 
case  to  show  when  the  next 
reading  is  taken  what  has 
been  the  highest  degree  of 
heat  or  cold  since  the  ther- 
mometer was  last  set. 


IWIRELESS  FOR 
TRANSMISSION 
LINE  SERVICE. 

A  new  and  important 
use  has  been  developed  for 
wireless  telegraphy  in  con- 
nection with  long-distance 
transmission  lines  of  elec- 
tric light  and  power  com- 
panies. For  communication 
between  stations  over  large 
systems  of  this  character, 
a  private  telephone  ser- 
vice usually  is  installed  along  the  route,  with 
lines  strung  on  the  transmission  poles  or 
towers,  making  them  liable  to  all  the 
troubles  to  which  the  power  leads  are  sub- 
jected. 

The  wireless  has  now  stept  in  to  eliminate 
the  many  inconveniences  and  interruptions 
of  communication  over  metallic  circuits  with 
absolute  and  reliable  service  under  all  condi- 
tions of  operation.  The  radio  installation 
seems  destined  to  be  placed  to  this  new  use 


with  increasing  range  of  accomplishments 
and  unquestioned  possibilities,  both  in  ser- 
vice and  maintenance  features,  becoming  a 
highly  essential  factor  for  extensive  power 
transmission  systems,  where  continuous 
and  positive  service  always  is  necessary. 

As  a  result  of  many 
practical  experi- 
ments, the  Southern 
Sierras  Power  Com- 
pany of  California  is 
rapidly  adopting  wire- 
less telegraphy  trans- 
mission and  reception 
between  its  important 
power  plants  and  sub- 
stations, readily  appre- 
ciating the  value  and 
dependability  of  radio- 
communication  at  all 
times.  The  company's 
system  extends  from 
Bishop,  Cal.,  to  the 
Imperial  Valley  district, 
a  distance  of  about  500 
miles,  consisting  for 
the  most  part  of  a 
double  three  -  phase 
high-voltage  circuit  on 
steel  towers.  The  sta- 
tions in  the  Bishop 
Creek  section,  on  the 
north  are  situated  on 
a  rugged  and  moun- 
tainous country,  a  territory  which  is  fre- 
quented by  sudden  and  exceptionally  severe 
storms  and  floods  and  extreme  weather  con- 
ditions. 

Radio  transmitting  and  receiving  sets 
have  been  installed  to  provide  communica- 
tion over  this  district,  as  well  as  at  other 
important  plants  on  the  main  transmission 
system  leading  into  San  Bernardino.  Plans 
are  being  perfected  to  provide  all  other 
primary  stations  with  wireless  equipment, 
effecting  a  complete  chain  for  radio-com- 
munication thruout  the  company's  territory. 
In  this,  the  equipment  installed  at  the  dif- 
ferent plants  will  be  arranged  for  a  par- 
ticular type  of  service,  in  some  instances 
allowing  for  a  communicating  radius  of 
500  miles  or  more,  and  in  others  for  con- 
nection with  the  next  sub-station  along 
the  route  only ;  dependent  upon  the  char- 
acter and  province  of  the  station.  The 
service,  when  entirely  installed  and  per- 
fected, will  be  used  both  for  regular  and 
emergency  purposes. 

It  is  interesting  to  note  that  the  station 
operators  have  welcomed  this  change  from 
the  telephone  and  telegraph  to  wireless ; 
and,  adept  in  the  use 
of  the  key  thru  the 
private  telegraph  sys- 
tem which  the  com- 
pany has  employed 
superimposed  upon 
the  telephone  lines  of 
the  system,  the  new 
installation  has  not 
brought  any  particu- 
lar departure  in  the 
general  workings  of 
the  station  organiza- 
tions. Moreover,  the 
company  has  been 
active  in  advancing 
the  knowledge  of  its 
operators  in  wireless 
and  the  wireless  code, 
furnishing  equipment, 
data  and  instructions 
to  make  them  fully 
proficient  in  this  new 
phase  of  science. — 
L.  R.  W.  Allison. 


ICE  CREAM  BY  ELECTRICITY. 

Did  you  ever  grind  an  ice-cream  freezer 
on  a  sultry  July  day,  and — eventually  lose 
about  4  pounds  avoirdupois,  along  with 
your  appetite  for  the  great  American  deli- 
cacy. That's  the  usual  case — but  our  friend, 
the  electrical  engineer,  has  perfected  an 
electric  motor  drive  for  turning  the  ice- 
cream freezer  which  is  warranted  not  to 


Ice  Cream  at  Any  Time,  When  You  Have 
the  Motor- Driven  Freezer  at  Hand.    It  Saves 
Its  Cost  in  a  Very  Short  Time. 

develop  a  "glass"  arm  when  the  cream  is 
about  half  frozen.  The  cost  of  one  hour's 
operation  for  this  welcome  servant  is  only 
a  fraction  of  a  cent  for  the  family  size  out- 
fit, and  the  initial  cost  is  soon  repaid.  It  is 
furnished  in  both  large  and  small  sizes. 


COLLECTING  TELEPHONE  TOLLS 
BY  MACHINE. 

A  device  used  as  an  accessory  to  tele- 
phone systems  and  which,  it  is  claimed, 
simplifies  the  collection  of  telephone  tolls 
among  tenants  in  apartment  houses,  hotels 
or  other  buildings  has  been  developed  by 
a  New  York  concern.  The  device  may  be 
placed  on  the  switchboard  ledge  and  con- 
nected with  a  coin  collector  in  every  apart- 
ment. The  machine  enables  the  operator 
to  determine  whether  a  coin  is  deposited 
in  any  particular  machine.  Such  notifi- 
cation will  correspond  with  the  different 
denominations  of  the  coins  used.  The 
operator  can  also  cause  any  number  of  de- 
posited coins  to  be  delivered  to  a  customer, 
either  for  the  purpose  of  making  change 
or  for  returning  the  equivalent  of  any  de- 
posited coin  or  coins.  If  a  tenant  does  not 
have  the  necessary  money  with  which  to 
pay  for  a  call,  the  operator  can  cause  a 
check  or  checks  to  be  issued  to  the  tenant, 


A  New  Device  Intended  to  Facilitate  the  Collection  of  Telephone 
Tolls  in  Apartment  Houses  and  Hotels.    It  Enables  the  Operator 
to  Check  Coins  Deposited  and  Also  to  "Make  Change." 


Even  the  Chinaman  has  found  electricity 
a  cheap  and  obedient  servant.  Thousands 
of  electric  irons  and  cooking  utensils  are 
used  in  China. 


who  in  turn  deposits  them  in  the  machine. 
The  value  indicated  on  these  checks  is  re- 
deemed by  the  customer  when  the  regular 
monthly  or  weekly  collections  are  made. 


August,  19 1 7 


THE  ELECTRICAL  EXFERIMENTER 


M5 


Unique  Electrical  Apparatus  Reads  the  Mind 


The  accompanying  illustrations  show  two 
extremely  interesting  electrical  apparatus 
of  French  design,  and  which  are  of  par- 
ticular moment  at  this  time,  when  we  hear 


words  and  sentences  flashed  before  the  eyes 
of  the  person  undergoing  the  test  and  also 
by  making  a  series  of  careful  observations 
of  the  various  time  periods  required  for  the 
person  to  more  or  less  accur- 
ately  memorize   th  se  captions, 
an  accurate  criterion  of  the  sub- 
ject under  test  is  obtainable. 

The  smaller  photograph  shows 
a  D'Arsonval  chronoscope  or 
electrical  time  mechanism  de- 
signed for  certain  applications  in 
psychological  research.  This 
apparatus  can  be  used  by  the 
average  person  with  very  little 
training.  Its  use  in  one  particu- 
lar instance  is  for  measuring 
the  exact  time,  in  thousands  of 
a  second,  required  for  auditory 
reaction,  or  in  other  words — 
the  time  required  for  the  nerve 
waves  to  pass  from  the  ears  and 
to  signal  the  brain  that  a  sound 
has  been  received  by  them.  The 
special,  double  contact  electrode 
used  by  the  expert  making  the 
test  is  provided  ith  a  small 
tapper,  so  designed  that  when 
this  is  used  to  strike  a  bell,  that 
its  movement  will  cause  the 
electrical  circuit  to  be  opened. 

Connected  with  the  clock- 
work of  the  electrical  chrono- 
scope is  a  second  two-contact 
electrode  shown  at  the  right  and 
which  is  held  in  the  hand  of  the 

Photos  from  Jacqjea  Boyer  ,  rp,  1 

How  Many  Words  Out  of  25  in  a  Group  of  Sentences  person  under  test.     ihe  proced- 

Can  You  Remember  If  They  Are  Flashed  Before  You  for  ure  is  as  follows:    The  expert 

a  Fifth  of  a  Minute?    With  This  Electric  Shutter  Device  strikes  the  bell  with  his  special 

and  a  Stop  Watch  the  Expert  Will  Know  Exactly  What  rfprtrnAP    aT1a    the    instant  the 

Kind  of  a  Memory  You  Have  electrode,   and   tne   msiant  me 


so  much  about  industrial  and  various  other 
kinds  of  psychological  research.  The  larger 
illustration  shows  a  precise  electrical  in- 
strument, comprising  an  electro-magnetic 
solenoid  which  operates  a  shutter.  When 
this  shutter  descends,  as  in  the  present  il- 
lustration, it  exposes  for  a  short  space 
of  time,  several  words,  or  in  some  cases 
several  sentences,  the  time  of  all  such  ex- 
posures being  governed  accordingly.  The 
person  taking  the  memory  test  with  this 
apparatus  sits  in  front  of  the  table  and  the 
operator  simply  presses  a  button  which 
causes  the  electric  solenoid  to  drop  the  shut- 
ter of  the  apparatus  quickly.  By  means  of 
a  stop-watch  the  time  during  which  the 
shutter  is  dropt  is  accurately  taken  note  of 


gong  sounds,  the  electrical  cir- 
cuit thru  the  chronoscope  is  opened,  per- 
mitting the  clock-work  to  rotate  the  hand 
over  the  dial,  which  is  spaced  off  in  small 
fractions  of  a  second.  As  soon  as  the 
subject  hears  the  sound  (which  is  not,  it 
should  be  noted,  at  the  exact  instant  when 
the  sound  strikes  the  membrane  or  drum 
of  the  ear,  but  an  appreciable  and  meas- 
urable time  afterward)  he  at  once  presses 
the  contacts  of  the  electrode  in  his  hand, 
and  this  actuates  an  electro-magnet  cm  the 
chronoscope,  causing  it  to  stop.  It  is  thus 
a  simple  matter  to  at  once  read  off  the 
fraction  of  a  second  required  for  audi- 
tory reaction  to  take  place.  


A  Gong  Is  Struck  with  the  Electric  Hammer  at  the 
Left;  When  You  Hear  the  Sound  You  Compress  the 
Hand  Switch  (at  Right)  and  the  Electric  Chronograph 
Registers  in  1-1000ths  of  a  Second  the  Time  Required 
for  Auditory  Response. 

by  the  expert  making  the  test,  which  time 
may  be  a  few  seconds  or  more,  depending 
upon  the  length  of  the  sentences  or  phrases, 
and  by  carefully  grading  the  make-up  of  the 


A  NEW  PORTABLE 

PYROMETER. 
By  Thomas  W.  Benson. 

Possibly  the  first  form  of  port- 
able pyrometer  or  means  for 
measuring  radiant  heat  was  the 
human  eye.  And  stranger  still  to 
relate  is  the  fact  that  some  of  the 
Old-timers  can  heat-treat  steel 
more  accurately  by  eye  than  some 
of  the  younger  experts  who  use 
the  various  forms  of  pyrometers. 

This  is  not  difficult  to  under- 
stand when  it  is  considered  that 
pyrometers  using  a  fixt  thermo- 
couple do  not  measure  the  tem- 
perature of  the  piece  under  treat- 
ment but  merely  the  temperature 
of  the  furnace  itself.  That  a  dif- 
ference exists  in  the  temperature 
of  the  two  requires  no  proof. 

The  portable  form  of  pyromet- 
er solved  this  by  measuring  di- 
rectly the  temperature  of  the  body 
itself  by  measuring  the  brilliancy 
or    amount  of    light  given  off. 
This  method  takes  advantage  of  the  fact 
that  the  temperature  of   steel  varies  dir 
rectly  as  its  luminosity  after  it  begins  to 
glow. 


The  illustration  shows  the  constructional 
details  of  a  unique  portable  pyrometer  re- 
cently brought  out.  This  device  is  about 
tie  size  of  a  large  tubular  flashlight,  being 
but  &'/2  inches  long.  It  can  be  easily  car- 
ried in  the  pocket,  is  sturdy,  accurate  and 
not  apt  to  get  out  of  adjustment. 

As  will  be  observed  the  case  contains  at 
the  lower  end  a  flashlight  battery  that  sup- 
plies current  to  the  small  incandescent  lamp. 
Above  the  lamp  is  placed  ai  opaque  dia- 
fram  in  which  is  mounted  a  diffusing  screen. 
By  means  of  small  rolls  and  knobs  mounted 
on  the  outside  of  the  instrument  it  is  pos- 
sible to  cause  a  tinted  film  to  pass  before 
the  diffusing  screen.  The  film  is  tinted  in 
the  varying  shades  of  color  assumed  by  a 
heated  body.  The  different  shades  are 
carefully  calibrated  with  relation  to  the 
corresponding  temperatures. 

At  the  left  is  seen  the  conical  eye-piece 
through  which  the  operator  views  the  hot 
body  under  observation.  A  small  mirror  is 
arranged  to  cover  one-half  of  the  field  of 
vision  as  shown.  This  mirror  reflects  the 
light  that  passes  thru  the  tinted  film  from 
the  lamp. 


Something  New  in  Portable  Pyrom- 
eters. This  Model,  which  May  Be 
Held  in  the  Hand,  Compares  the 
Luminous  Valve  of  the  Hot  Body  with 
That  of  an  Illuminated  Tinted  Film. 


In  use  the  rolls  are  turned  until  both 
halves  of  the  field  correspond  exactly  in 
shade,  then  by  referring  to  the  dial  it  is 
possible  to  determine  accurately  the  tem- 
perature. It  is  possible  to  build  the  de- 
vice in  practically  any  range,  but  the  more 
common  ranges  are  1000-1800  degrees  Fah- 
renheit and  1800-2300  degrees  Fahrenheit. 


NEW  YORK  HERALD  WIRELESS 
STATION  AGAIN  IN  COMMISSION. 

The  wireless  station  of  the  New  York 
Herald  was  formally  returned  to  commis- 
sion on  February  twenty-eighth  in  its  new 
quarters  atop  the  United  States  barge 
office  in  New  York.  Mr.  John  Bottom- 
ley,  vice-president,  secretary  and  treasurer 
of  the  Marconi  Wireless  Telegraph  Com- 
pany of  America,  New  York,  was  present 
at  the  opening  ceremonies.  This  station 
was  placed  under  censorship  last  October. 


246 


THE  ELECTRICAL  EXPERIMENTER 


August,  1917 


1  i 


'OU'VE  been  wantin'  proof. 
There  it  is  I"  With  a  gasp  of 
astonishment  the  group  about  the 
big  stove  in  Preston's  store 
leaned  forward  with  a  jerk,  necks 
craned,  mouths  and  eyes  wide,  staring  in 
wonder  at  the  object  old  Tom  Waldon  had 
drawn  from  beneath  his  big  sheepskin  coat. 

Cylindrical  in  shape,  it  was  made  of  heavy 
steel,  measuring  


The  Radio  Bomb 

By  C.  M.  ADAMS 

the  middle  o'  the  road  at  the  end  o'  my  lane 
and  my  hoss  almost  stept  on  it.  So  I  gets 
out  and  picks  it  up  after  I'd  seed  it  was 
wet." 

"Suppose  it  was  gunpowder.  What  does 
that  prove  anyhow?"  Dick  demanded,  re- 
suming his  seat  on  the  cracker  barrel. 

"He  put  it  there !"  the  old  man  declared. 

"Did  vou  see  him?" 


about  two  feet  in 
length  by  four 
inches  in  diam- 
eter, and  painted 
a  brilliant  red, 
save  at  one  end 
where  the  figure 
"6"  was  stenciled 
in  black. 

"What  does 
that  prove  ?  " 
Dick  Preston  de- 
manded, from  his 
perch  on  a  crack- 
er barrel. 

"Prove?"  Wal- 
don repeated, 
glaring  up  at  the 
boy  who  ques- 
tioned him.  "Just 
what  I've  been 
tellin'  you  —  that 
he's  a  'spy'  and 
he'll  blow  us  all 
up  if  we  don't 
stop  him !  Why, 
me  and  my  hoss 
would've  been 
Mowed  to  pieces 
this  mornin'  if  it 
hadn't  been  wet 
from  layin'  in  the 
snow  so  long!" 

"What  is  it?" 
Pete  Bailey  asked 
in  an  awed  whis- 
per. 

"A  bomb !" 

With  a  clatter 
of  upsetting 
chairs  the  terror- 
stricken  group 
fled  precipitately 
to  the  opposite 
end  of  the  store. 

"Don't  get 
scared !"  Dick 
laughed,  slipping 
down  from  his 
barrel  and  taking 
the  tube  from  the 
old  man.  "Look !" 

With  a  twist  of 
the  threaded  cap 
he  removed  one 
end  of  the  tube 
and  poured  out 
in  his  free  hand 
a  dirty  brown 
wet  powder. 

"It's  gunpow- 
der!" Waldon 
exulted. 

"Powder,  noth- 
ing; it's  sand  and 
ashes  and  dirt !" 
Dick  scoffed. 
"Watch !" 

He  jerked  open 
the  door  of  the 
glowing  stove  and  threw  in  a  generous 
handful  of  the  material.  On  the  red-hot 
coals  it  lay  in  an  inert  mass,  while  one  by 
one  the  group  tiptoed  cautiously  back  to  see 
and  regain  courage. 

"Course  it  won't  burn  when  it's  wet,"  old 
Tom  defended.  "That's  why  it  wouldn't 
go  off  this  mornin'.    It  was  layin'  right  in 


"Them  boxes  and  crates  and  barrels  and 
things  he  had  me  haul  up,  was  mighty 
heavy,"  Tom  Sullivan  affirmed. 

"Yes,  and  what's  that  thing  he's  been  car- 
ryin'  around  that  pretends  to  be  a  surveyin' 
instrument?"  Pete  Bailey  demanded. 

"All  that  don't  prove  a  thing!"  Dick  re- 
torted angrily.'  "Just  because  he  doesn't 
choose  to  tell  you  what  he's  here  for,  and 
 everything  about 


".  .  .  Straight  as  an  Arrow  the  Uncanny  Thing  Came,  Showing  Momentarily  the  Glimpse 
of  a  Humming  Propeller.  ...  A  Huge  Column  of  Spray  and  Ice  Spouted  Skyward  From 
the  Jam,  and — Where  Had  Been  the  Towering  Ice  Barrier,  the  People  of  Pine  Flat  Saw  the 
River — Yellow,  Swift  and  Turbulent,  Running  Free  and  Clear  Thru  the  Gap  and  Down  Past 

the  Hamlet." 


"Who  else  would?"  Waldon  parried. 
"Who's  been  prowlin'  around  here  all  hours 
o'  the  day  and  night?  Who's  been  livin'  in 
a  cabin  on  Pine  Mountain  by  himself  all 
winter  and  not  sayin'  what  he's  up  there 
for?  Couldn't  he  shoot  up  the  whole  val- 
ley with  a  cannon  up  there?" 


his  business,  you 
think  he's  a  spy. 
Why  don't  you 
be  reasonable?" 

"I  am  reason- 
able," old  Tom 
grinned  mali- 
ciously. "I  hain't 
takin'  no  chances. 
I  sent  down  to 
Squire  Jefferson's 
this  mornin'  for 
a  search  warrant 
and  when  it  gets 
here,  I  as  con- 
stable, will  go  to 
that  cabin  and 
see  just  what  he's 
doing  there  and 
find  out  if  he 
can't  give  some 
reason  for  actin' 
the  way  he  does  !" 

"That's  the 
stuff.  Good  for 
you,  Tom!''  a 
half  dozen  en- 
dorsed. 

"Yes  sir,  I 
think  it  was  time 
we  was  a  doin' 
somethin'  besides 
sittin'  around 
here  talkin'  and 
wonderin'  and 
lettin'  him  have 
a  chance  to  blow 
us  into  next 
week !"  the  old 
man  continued 
importantly, 
opening  his  coat 
so  that  the  nickel- 
plated  star 
showed  plainly. 
"This  here  bomb," 
and  he  tapt  the 
tube  in  his  lap, 
"sort  o'  set  me  to 
thinkin'  and  I'm 
goin'  up  the  first 
thing  in  the 
mornin'  if  that 
search  warrant 
comes  up  on  the 
mail  this  after- 
noon." 

"You're  doin' 
just  right,  Tom !" 
Pete  Bailey  de- 
clared. "I  was 
just  wonderin'  if 
you  was  goin'  to 
let  him  run  loose 
around  here, 
while  you're  con- 
stable." 

"You  bet  1 
won't !"  that  offi- 
cial boasted. 
But  Dick  Preston  did  not  endorse  old 
Tom  Waldon's  new  decision.  For  a  mo- 
ment he  sat  on  his  cracker  barrel,  staring 
in  surprise  at  the  old  constable  and  the 
group  about  the  stove  which  was  so  loud 
in  its  support  of  his  new  plan  of  deal- 
ing with  the  mysterious  and  undesirable 
stranger. 


August,  1917 


THE  ELECTRICAL  EXPERIMENTER 


247 


And  then  without  a  word  he  slipt  to  the 
floor  and  past  out  into  the  house  which  ad- 
joined the  store  and  mounted  the  stairs 
to  the  room  which  he  occupied  under  the 
eaves. 

A  worried  frown  puckered  his  brow  as 
he  seated  himself  at  a  table  covered  with 
a  bright  new  set  of  wireless  telegraph  in- 
struments, and  his  frown  deepened  as  he 
adjusted  the  detector  and  inductances. 

"Suspicious  old  fool !"  he  growled  as  he 
slipt  on  the  head  receivers.  "I  hope  we 
can  beat  him  !" 

"H  D,  H  D,  H  D,  D  P,"  the  white  spark 
in  the  gap  crackled  in  clean-cut  Continental 
as  he  tapt  the  key. 

Again  the  call  repeated  before  he  threw 
over  the  aerial  switch. 

Then,  "O  K,  D  P,  H  D,"  sounded  the 
clear  reply  in  his  receivers. 

"News  to  report.  Coming  up,"  the  spark 
snapt. 

"O  K,"  the  reply  buzzed. 

Slipping  receivers  from  his  head  Dick 
drew  on  mackinaw,  mittens  and  cap,  as  he 
went  rapidly  down  the  stairs,  and  paused  on 
the  back  porch  to  adjust  a  capable  looking 
pair  of  snowshoes. 

Then  off  up  the  slope  which  rose  ab- 
ruptly at  the  rear  of  the  building  he  swung, 
laying  a  course  eastward  to  where  Pine 
Mountain  reared  its  low  broad  bulk  against 
the  skyline.  For  a  half  hour  he  climbed, 
leaving  behind  the  hamlet  sprawled  in  the 
valley  on  the  broad  flat  just  below  the  nar- 
row gorge  where  Pine  River  rushed  swiftly 
between  steep  high  banks.  But  not  once 
did  he  turn  to  look  back  at  the  cluster  of 
houses  or  to  glance  up  at  the  dazzling  glory 
of  the  late  afternoon  sun  on  the  clean  crisp 
whiteness  of  the  deep  snow  which  covered 
the  whole  country. 

With  the  worried  frown  deepening  be- 
tween his  brows  he  mounted  steadily  until 
he  topt  the  last  rise  and  came  out  on  a  broad 
flat  summit,  where,  in  the  midst  of  a  large 
clearing,  stood  a  cahin. 

It  was  different  from  the  usual  mountain 
cabin  in  that  it  was  long,  narrow  and  low 
and  windowed  at  but  one  end.  Otherwise, 
except  that  from  one  end  a  span  of  glit- 
tering wireless  antennae  rose  in  a  long 
slant  to  a  tree  at  the  edge  of  the  clearing, 
it  was  quite  the  usual  rough  log  structure. 

Dick  drew  off  his  snowshoes  at  the  door 
and  stept  inside  without  knocking.  He 
found  himself  in  a  small  room,  evidently 
partitioned  off  from  the  main  windowless 
apartment.  Stove,  bunk,  a  table  spread  with 
a  litter  of  papers,  and  the  other  usual  furni- 
ture made  it  seem  like  the  ordinary  cabin 
room.  But  at  one  side  stood  a  table  on 
which  was  spread  the  elaborate  wireless  in- 
struments connected  to  the  antennae  wires. 
It  was  similar  to  Dick's  set  except  that 
above  the  table  was  a  row  of  carefully  di- 
aled instruments  marked  "Distance — height 
— speed — direction — shot  control." 

Dick  had  barely  entered  and  drawn  off 
his  mackinaw  when  the  door  leading  into 
the  other  room  opened  and  a  tall  man  whose 
erect  military  poise  contrasted  strangely 
with  his  grease-smeared  overalls,  entered. 

Dick  saluted. 

"Good  afternoon  Captain,"  he  said. 

"Hello,  Dick,"  the  tall  man  replied,  re- 
turning the  salute.  "What's  the  matter? 
Didn't  the  tests  work  right?" 

"Oh,  they  were  fine !"  Dick  answered. 
"It's  old  Tom  Waldon  again." 

"Oh,  your  worthy  constable  and  defender 
of  the  peace  and  safety  of  the  common- 
wealth," Captain  Hardy  laughed,  as  he  drew 
up  a  chair  beside  the  stove. 

"Its  nothing  to  be  laughed  at,"  Dick  pro- 
tested, while  the  concern  deepened  in  his 
face.  "He's  sent  for  a  search  warrant  and 
is  coming  up  here  to  investigate  you  and 
what  you've  been  doing." 

"Whe — e — e — ew!"  the  tall  man  whistled. 


"What's  the  matter  now?" 

"Number  '6'  fell  in  front  of  his  house 
last  night.  He's  all  worked  up  about  it  and 
now  he's  certain  you're  a  spy.  The  search 
warrant  will  be  here  tomorrow  morning  if 
the  mail's  on  time;  then  he'll  ransack  the 
whole  place.  If  he'd  only  keep  his  fool  no- 
tions to  himself  and  not  try  to  be  buttin' 
around  into  other  people's  business !"  and 
Dick  kicked  savagely  at  a  block  of  cord- 
wood  beside  him. 

"Of  course  I  don't  want  to  stir  up  any 
trouble,"  Hardy  began  thoughtfully.  "You 
know  I  could  resist  search  by  him." 

"But  he's  got  the  whole  bunch  worked  up 
to  believing  the  same  as  he  does,"  Dick  put 
in  despairingly. 

"Yes,  that's  true,"  Hardy  replied.  "But 
to  come  back  to  something  more  important, 
how  did  the  tests  come  out?" 

"I  have  the  locations  here,"  Dick  replied, 

piiiiiiiniiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiH 

=  WATCH  FOR  THE  SEPT.  "E.E."  g 

g  "X-Ray  Tubes  for  High-Frequency  g 

H  Coils." — A  subject  of  extreme  interest  g 

|  to  all  those  owning  radio  transmit-  g 

H  ting    apparatus    or    high    frequency  g 

'  coils,  by  Dr.  Frederick  F.  Strong.  - 

g  New  Electro-therapeutic  apparatus,  g 

g  by  H.  Rosenthal.  H 

="  The  Marvels  of  Radio-activity.  Part  - 

g  77    {with  some   wonderful   illustra-  g 

g  Hons),  by  Jerome  S.  Marcus,  B.Sc.,  g 

|  (Ch.E.)  "                                     f  | 

=  Invisible  Radio  Aerials  that  "Spies"  == 

g  might  use.  g 

g  The  first  electric  apparatus — The  g 

g  first  incandescent  lamp;  the  first  .dy-  g 

g  namo;  the  first  motor,  et  cetera.  g 

H  A  New  Popular  Scientific  Article,  g 

g  by  Rogers  D.  Rusk,  B.Sc.  g 

g  Selenium   Cell,  Design   and  Con-  g 

g  struction  by  Thomas  IV.  Benson.  g 

g  An    Automatic    Storage    Battery  g 

|  Charger,  by  Lewis  Scrivcn.  g 

g  Making  an  Electric  Clock — Part  I,  = 

g  by  Thomas  Reed.  g 

=  Are  There  Currents  About  a  Mag-  g 

g  net?  by  F.  F.  Mace.  g 

g  The    Franklin    Electric    Club,    as  g 

g  founded  by  William  J.  Hammer,  and  g 

g  his  message  to  the  "Electrical"  and  g 

g  "Radio-Bugs"  of  To-day.  g 

g  Unusual  Entertainment  Stunts  with  g 

g  High     Frequency     Currents — With  g 

g  several    startling    photos    of   actual  g 

g  stunts.  g 

g  Announcement  of  Prise  Winners  in  s 

g  the  "What  to  do  with  your  radio  set  g 

g  during  the  war"  contest.  g 

g  Besides  these  leading  articles  the  g 

g  September  number  will  fairly  bristle  g 

g  with  dozens  of  live,  up-to-the-minute  g 

g  electrical,  scientific  and  radio  articles  g 

g  of  interest  to  all  of  our  readers.  g 
Illlllllllllllllllllllllllllllllilllllllllllllllllllllllli 

drawing  a  notebook  from  his  pocket.  "Num- 
ber '6'  fell  in  front  of  his  place,  and  the 
rest — " 

For  a  half  hour  the  two  bent  over  a  de- 
tailed map  of  the  valley  while  they  com- 
pared figures  and  locations. 

"That's  fine !  The  biggest  variation  is 
about  four  feet  and  that's  corrected  by  the 
adjustments  I've  been  making  to-day," 
Hardy  breathed  in  satisfaction,  as  he 
straightened  up.  "Now  I  think  if  we  can 
run  a  test  with  a  real  charge  instead  of  those 
dummies  we  can  be  prepared  to  announce 
results." 

"I  know  a  good  target  for  it,"  Dick  vol- 
unteered. "Its  a  big  pile  of  drift  and  rub- 
bish down  by  the  bend  just  below  town. 
Its  doesn't  belong  to  anyone.  See — ■"  and 
he  pointed  out  the  spot  on  the  map. 

"Good!  Just  the  thing!"  Captain  Hardy 
endorsed.    "What  do  you  say  we  try  it  this 


evening?  If  your  friend  the  eminent  de- 
tective is  to  come  up  here  to-morrow  with 
his  search  party,  we  can  tell  him  everything, 
if  the  test  is  successful." 

"That  suits  me,"  Dick  agreed. 

"Very  well,"  Hardy  replied.  "We'll  set 
the  time  for  nine  o'clock  then.  Get  your 
'interference'  going  and  we'll  see  how  this 
tryout  works." 

"All  right,  sir.  I'll  be  ready,"  Dick  re- 
plied. "And  I  hope  that  warrant  doesn't 
get  here  in  time,"  he  added  as  he  smiled 
thru  his  anxious  frown. 

"Don't  you  worry  about  that,"  Hardy  ad- 
vised. 

"Yes,  but  it  makes  me  sick,"  Dick  pro- 
tested. "When  a  man's  trying  to  do  what 
you  are  and  then  for  him  to  plot  against 
you  !    It  makes  me  want  to  hit  him  !" 

"Oh,  never  mind,"  Hardy  laughed.  "Just 
you  go  to  bed  to-night  and  get  plenty  of 
sleep.  We  may  have  to  run  another  test  if 
this  one  doesn't  work  and  I'll  have  to  have 
you  fresh  and  ready,  because  you're  re- 
sponsible for  half  the  success  of  this  thing." 

"No — no !"  Dick  protested,  while  he 
blushed  with  pleasure. 

"Yes,  but  you  are,"  the  tall  man  insisted. 
"I  couldn't  have  done  a  thing  without  your 
'interference'  and  the  other  ways  you've 
helped.  So  just  go  along  and  forget  that 
old  spy-chaser." 

But  Dick  could  not  shake  off  the  thought 
of  what  the  old  man  might  do  to  wreck 
Captain  Hardy's  plans.  All  the  way  down 
the  long  white-covered  slope  he  wondered 
and  pondered,  as  he  tried  to  find  some  way 
out  of  the  complication  into  which  _  his 
friend  was  drifting  with  the  local  officials. 

"Has  the  mail  come  in  yet?"  he  asked  his 
father  as  he  tramped  into  the  kitchen  and 
found  the  family  at  supper. 

"No,"  Joe  Preston  replied.  "The  trail's 
getting  too  soft.  That  wind's  melting  the 
snow  fast.    Didn't  you  notice  it?" 

Then  Dick  remembered.  While  he  had 
been  in  the  big  cabin  on  the  top  of  Pine 
Mountain  the  wind  had  shifted  to  the  south 
and  with  it  had  come  balmy  warm  air  which 
had  rapidly  softened  the  hard-crusted  snow. 

"I  don't  like  this  spell  at  all.  There's 
too  much  ice  and  snow  on,"  Joe  Preston  re- 
marked. 

But  Dick  rejoiced  secretly.  It  might  so 
impede  the  trails  as  to  make  it  impossible 
for  old  Tom's  search  warrant  to  arrive 
in  time  from  the  Squire  down  the  river. 
.  His  anxiety  was  gradually  relieved  as  all 
that  evening  the  warm  south  wind  blew  and 
the  snow  melted.  It  was  dripping  from  the 
eaves  in  pattering  cascades  when  he  went 
upstairs  into  his  room  about  eight  thirty, 
after  preparing  his  lessons  for  the  'morrow. 

But  he  forgot  it  and  even  old  Tom  as  he 
adjusted  his  wireless  instruments  carefully 
and  cleaned  all  the  contacts  and  tightened 
connections. 

Then  at  a  quarter'  before  nine  his  call 
came  in,  "D  P,  D  P,  D  P,  H  D." 

"O  K,  H  D,  D  P,"  he  responded  and  the 
replv  came  back. 

"Ready !" 

Throwing  over  the  aerial  switch  he  set 
to  work  methodically.  For  the  next  fifteen 
minutes  he  sent  anything  and  everything, 
stopping  at  intervals  of  several  seconds  to 
make  swift  changes  in  his  transmitting  wave 
length  adjustment. 

Then  just  as  the  hands  of  the  watch 
which  lay  before  him,  pointed  to  nine,  he 
heard  faintly  the  muffled  boom  of  an  ex- 
plosion from  down  the  river,  and  with  a 
satisfied  sigh  slipt  off  his  receivers  and 
crawled  into  bed. 

Day  had  scarcely  broken  the  next  morn- 
ing when  he  was  awakened  by  an  unusual 
sound.  Sitting  bolt  upright  in  bed  he  lis- 
tened for  several  moments  before  he  recog- 
nized what  it  was. 

(Continued  on  page  279) 


248 


THE  ELECTRICAL  EXPERIMENTER 


August,  iq 1 7 


Dionic  Water  Tester  Operates  by  Electricity 


WHAT  is  known  as  a  dionic  water 
tester  has  been  recently  perfected 
and  appears  to  be  an  extremely 
practical  apparatus  for  testing  water,  or 
any  dilute  solution.  So  simple  and  so  di- 
rect is  its  operation  that  any  unskilled  per- 
son can  make  accurate  tests,  and  even  de- 


water,  so  altering  the  effective  cross  area 
of  the  liquid  path.  This  thermometer  is 
supported  in  a  sliding  holder  L,  which 
moves  in  guides  H,  H,  and  which  carries  an 
index  I  ranging  over  a  scale  J,  calibrated 
in  degrees  centigrade.  After  the  water  to 
be  tested  has  been  poured  into  the  funnel 
F  and  fills  the  tube  G,  the  reading  on  the 
thermometer  is  noted;  and  its  sliding 
holder  is  moved  until  the  reading  of  the 
index  I  on  the  scale  J  corresponds  with 
the  thermometer  reading.  This  operation 
compensates  for  the  change  of  conductivity 
due  to  temperature,  and  the  reading  given 
on  the  dial  of  the  meter  M  is  the  conduc- 
tivity of  the  water  at  20°  C. 

By  turning  the  handle  W  of  the  dynamo, 
a  current  is  generated  which  traverses  the 
meter  and  the  water  in  the  conductivity 


of  one  megohm,  and  we  must  be  content 
to  call  it  simply  one  unit.  In  the  conduc- 
tivity meter  for  dilute  solutions  the  scale 
extends  from  zero  up  to  2,000  units. 

The  tube  is  mounted  in  a  strong  teak  case 
designed  to  be  as  compact  as  possible  and 
when  opened  to  afford  a  firm  support  for 
the  tube  during  test.  It  is  so  constructed 
that  by  pouring  water  into  the  funnel  F. 
and  allowing  it  to  overflow  through  the 
outlet  pipe  O,  every  part  of  the  tube  is 
thoroly  washed  out.  A  drain  pipe  D,  of 
pure  rubber,  is  provided  at  the  bottom  for 
the  purpose  of-  drawing  off  the  contents  at 
the  conclusion  of  a  test.  Normally,  the 
drain  is  closed  by  a  pinch-cock.  Water 
may  be  left  standing  in  the  tube  for  days 
at  a  time  without  the  slightest  trace  of  con- 
tamination from  the  rubber  being  traceable. 
All  the  user  has  to  do  in  order  to  connect 
the  tube  to.  the  meter  is  to  push  the  plug 
into  the  socket. 


General  Appearance  of  New  Dionic  Electric  Water  Tester.     Operates  on  the   Principle  that 
Relative  Chemical  Make-up  of  Water  and  Its  Electrical  Conductivity  Correspond. 


tect  and  measure  traces  of  impurity  so 
small  as  entirely  to  escape  chemical  analysis. 

The  detection  and  estimation  of  impuri- 
ties dissolved  in  water  and  the  measure- 
ment of  the  strength  of  weak  solutions 
have  hitherto  been  carried  out  by  chemi- 
cal tests  of  more  or  less  complexity.  The 
dionic  water  tester  involves  the  substitu- 
tion of  an  extremely  simple  electrical  meas 
urement. 

When  the  nature  of  any  substance  in 
solution  is  known,  the  conductivity  of  the 
solution  is  a  measure  of  its  amount;  and 
the  dionic  tester  is  therefore  able,  by  a 
simple  measurement  of  conductivity,  to  de- 
termine to  a  high  degree  of  accuracy  the 
strength  of  the  solution  under  test.  The 
weaker  the  solution,  the  more  sensitive  be- 
comes the  method,  so  that  the  instrument 
is  peculiarly  well  adapted  for  detecting  the 
contamination  of  water.  Xot  only  is  it 
possible  by  the  use  of  the  dionic  instru- 
ment to  measure  amounts  of  salt  in  solu- 
tion too  small  to  be  detected  by  chemical 
means,  but  it  performs  in  a  few  seconds, 
and  in  the  hands  of  totally  unskilled  per- 
sons, work  which  a  skilled  man  would  take 
some  time  to  carry  out  by  chemical  methods. 

It  does  not,  of  course,  discriminate  be- 
tween one  kind  of  substance  and  another ; 
analysis  alone  can  do  that.  But  in  most 
instances  in  which  water  testing  is  carried 
out  for  engineering  and  kindred  purposes, 
the  substance  present  in  the  water  is  well 
known.  Such  tests  are  not  made  for  pur- 
poses of  analysis,  but  to  find  out  how  much 
of  a  known  substance  is  present  in  the 
water;  and  in  all  these  cases  the  dionic 
meter  gives  the  required  answer  with  a 
rapidity  and  simplicity  unapproached  by 
any  chemical  test. 

The  complete  apparatus  is  shown  here, 
where  G  is  a  glass  tube  to  contain  the 
water  under  test,  and  A  and  B  are  the 
electrodes  for  passing  the  electric  current 
thru  the  water.  The  electrodes  are  con- 
nected by  wires  to  a  direct-reading  con- 
ductivity meter  M,  and  a  continuous-cur- 
rent hand-driven  dynamo  E. 

The  thermometer  T,  measures  the  tem- 
perature of  the  water  under  test,  and  is 
capable  of  being  lowered  or  raised  in  the 


tube  G.  The  pointer  of  the  meter  is  de- 
flected, and  comes  to  rest  at  some  point 
upon  the  scale  which  directly  indicates  the 
conductivity  of  the  water  in  the  tube  cor- 
rected to  20°  C.  The  test  is  completed  as 
soon  as  the  pointer  has  come  to  rest,  that 
is  to  say,  in  two  or  three  seconds. 

The  conductivity  meter  is  a  novel  instru- 
ment; it  measures  directly,  and  without  cal- 
culation, the  conductivity  of  any  electroly- 
tic solution  in  the  tube  to  which  it  may  be 
connected.  The  indication  is  given  by  an 
index  which  ranges  over  an  engraved  scale, 
graduated  in  units  of  conductivity.  Con- 
ductivity (specific  conductance)  is  the  re- 


TWO  NEW  RADIO  STATIONS  FOR 
COLOMBIA. 

It  is  reported  that  the  two  Marconi  wire- 
less outfits  purchased  by  the  Colombian 
Government  some  time  ago  will  be  deliv- 
ered soon.  It  is  intended  to  establish  these 
two  stations  at  Arauca  and  Orocue.  The 
former  is  situated.'  on  the  Arauca  River 
where  it  forms  the  boundary  between  Co- 
lombia and  Venezuela,  and  the  latter  is  cn 
the  Meta  River  some  200  miles  east  of 
Bogota. 

VALUABLE  NEW  DEPOSITS  OF 
PLATINUM. 

Platinum  is  becoming  so  scarce  that 
Russia,  where  most  of  the  mines  are,  is 
seeking  new  deposits.  M.  Chtein  published 
in  Promichlennost  i  Torgorlia  last  year  a 
calculation  showing  that  the  Ural  mines 
would  be  exhausted  in  from  fifteen  to 
twenty  years.  But  the  Russian  paper  Gor- 
no-Zadvodskoie  Dielo  announces  the  recent 
discovery  of  a  very  rich  deposit  in  the 
Vilyui  River  near  where  it  flows  into  the 
Kundai,  in  the  Yakutsk  region.  It  is  found 
mixed  with  gold  in  the  sands  of  this  river 


Diagram  of  Dionic  Water  Tester  Showing  Tube' Provided  with  Automatic  Compensa- 
tion for  Temperature,  High  Tension  Hand   Dynamo  and  Conductivity  Meter. 


ciprocal  of  specific  resistance,  and  the  most 
convenient  unit  for  the  purpose  of  water- 
testing  is  the  reciprocal  of  one  megohm. 
No  one  has  given  a  name  to  the  reciprocal 


and  its  tributaries,  from  which  the  natives 
wash  it  and  obtain  an  ore  that  is  50  per 
cent  pure  platinum  and  50  per  cent  iridium, 
palladium  and  ruthenium. 


August,  1917 


THE  ELECTRICAL  EXPERIMENTER 


249 


"Perpetual  Motion " 


Here's  Your  Chance,  "Electrical  Bugs,"  to  Become  Internationally  Famous.  Design  a  Perpetual  Motion  Scenic  Railway  Like  That  Shown; 
the  Descending  Cars  Pump  Electrical  Energy  Back  Into  the  Storage  Battery;  the  Ascending  Cars  Are  Helped  Over  the  Peaks  by  Cur- 
rent from  the  Battery.    For  the  Best  100  Words  Explaining  Why  This  Device  Will  or  Will  Not  Keep  Going  For  Years,  Ignoring  Wear 

and  Tear,  We  Wiii  Give  a  Year's  Subscription  to  the  "E.  E." 


WHEN  your  Editor  was  at  the  ten- 
der (?)  age  of  eleven — yes,  tough 
old  birds  like  us  were  tender  once, 
strange  as  it  may  seem — he  had, 
just  like  the  rest  of  us  bugs, 
rather  strange  ideas  about  electricity  and 
mechanics.  Perpetual  motion  had  a  great 
and  attractive  fascination  and  appealed 
"mos'  pow'fully"  to  his  imagination.  Yes, 
you  said  it — imagination  is  his  middle  name 
— altho,  bless  his  dear  ignorance,  in  those 
innocent  days  he  was  as  yet  not  aware  of 
the  great  axiom,  to  wit:  "If  you  wish  to 
lift  yourself  by  your  own  boot-straps,  do  it 
in  an  elevator !" 

Just  like  all  budding  electrical  bugs,  his 
first  revolutionary  invention  consisted  of 
the  time-honored  perpetual  motion  where 
you  take  a  motor  and  a  dynamo  both  of 
the  same  size,  mind  you,  and  connect  them 
together  by  a  belt.  Then  you  connect  the 
binding  posts  of  the  motor  to  those  of  the 
dynamo,  and  let  'er  go !  Of  course  you 
must  give  the  belt  a  push,  in  order  to  start 
the  rinktum  going,  that  much  is  clear.  In 
that  case  you  generate  a  little  current  in 
the  dynamo  which  feeds  the  motor.  The 
latter  in  turn  runs  the  dynamo  by  means 
of  the  belt.  In  a  few  seconds  the  sys- 
tem will  run  so  fast  that  the  dynamo — 
bless  its  soul — will  have  a  generous  amount 
of  juice  left  over,  which  latter  will  feed 
all  your  various  contraptions  in  your  shop. 
Of  course  once  started  the  system  will  run 
forever.    Sounds  fine. 

Well,  anyway,  your  Editor  was  one  of 
those  fool  kids  who  did  not  believe  in 
theory  alone.  Not  him.  He  meant  to  try 
it  out.  He  had  a  nice  enough  motor,  but 
no  dynamo.  True,  the  patient  old  motor 
had  been  taken  apart  so  often,  and  its  field 
and  armature  had  been  rewound  so  fre- 
quently that  it  looked  decidedly  disreput- 
able— but  it  ran,  yes,  on  one  Leclanche ! 


Speak  of  a  finely  balanced  armature! 
Well,  after  committing  almost  every  imag- 
inable crime  on  the  bill  of  fare,  with  the 
possible  exception  of  murder,  enough  cash 
was  scraped  together  to  send  for  that 
dynamo.  In  the  catalog  it  said  that  it 
gave  4  volts  and  4  amperes  at  3,000  R.P.M. 
"Takes  remarkably  little  power — can  be 
driven  nicely  from  a  sewing  machine,  in 
order  to  charge  storage  cells,  etc.,  etc." 

Well,  in  those  days,  mail  order  firms 
were  not  so  careful  about  their  statements 
as  they  are  today.  At  any  rate  your  young 
hopeful  for  the  benefit  of  all  bugs  in  the 
Universe  concerned,  wishes  to  make  pub- 
lic the  fact  that  charging  storage  batteries 
with  a  dynamo  from  a  sewing  machine  can- 
not be  termed  as  a  howling  success.  He 
tried  it.  Oh  yes,  frequently.  Once  for  al- 
most ten  minutes  at  a  time.  For  the  first 
19  seconds  the  dynamo  ran  at  the  pre- 
scribed 3000  R.P.M.  It  ran  remarkably 
easy  too.  At  the  end  of  the  first  minute 
its  speed  had  dropt  to  about  1100 
R.P.M.  At  the  end  of  the  10  minutes  its 
speed  had  gone  to  minus  10  R.P.M.  From 
this  you  will  infer  correctly  that  the  stor- 
age battery  now  ran  the  dynamo  as  a 
motor,  and  the  latter  ran  the  sewing  ma- 
chine flywheel  and  the  treadle!  This  was 
decidedly  unpleasant.  So  he  went  at  it 
again,  first  taking  off  coat  and  collar.  This 
time  he  lasted  eight  minutes.  But  the 
storage  battery  got  some  juice  in  its  car- 
cass anyway,  that  afternoon.  We  should 
guess  approximately  2J4  watts  net.  And 
next  day,  too,  your  Editor-to-be  had  such 
sore  legs  that  he  could  not  possibly  walk. 
But  it  works.    The  catalog  was  right !  | 

But  we  are  running  ahead  of  the  story. 
At  any  rate,  the  dynamo  soon  arrived.  It 
was  a  great  day.    Birds  sang  in  the  trees. 

And  the  squirrel  jumped  hush,  hush, 
From  the  tree  into  the  bush! 


From  this  you  have  correctly  deducted 
that   it   was    a   spring    day.     Ah,  noble 
spring  .  .  .  and  if  we  had  been  a  trifle 
older  we  might  have  completed  the  "pome"  _ 
with : 

Maiden  aunts  grow  sentimental 
While  the  landlord  claims  the  rental! 
Luckily,  however,  we  did  not  know  oldish 
maids  and  their  sentimental  mental  scents, 
nor  were  we  as  yet  much  troubled  with 
ghoulish  landlords. 

At  least  we  were  not  while  we  stood  in 
a  perfect  trance  before  that  dynamo,  fresh- 
ly unpacked,  standing  there  in  its  virgin 
beauty  of  brightly  red  lacquered  field  cast- 
ings, dazzling  green  magnet  wire  covering 
graceful  limbs,  and  bright  nickel  binding 
posts,  the  whole  mounted  on  a  heavy  real 
oak  base.  While  we  stood  there  gazing 
with  love  and  admiration  in  our  eyes,  like 
a  mother  gazes  at  her  first  born  babe,  a  de- 
licious shiver  ran  up  and  down  our  back 
when  we  thought  of  the  sumptuous  monu- 
ment that  would  garnish  the  public  square 
which  a  thankful  world  had  erected  in  our 
honor,  after  our  death !  The  inscription 
was  to  read : 

"To  the  inventor  of  the  first  Perpetuum 
mobile." 

To  make  an  unpleasant  tale  abbreviated, 
let  us  disclose  the  fact,  that  little  time  was 
lost  in  trying  out  the  great  invention. 
Everything  was  connected  carefully,  the 
belt  was  tightened  correctly,  and  the 
bases  of  both  motor  and  dynamo  screwed 
down  tight.  The  supreme  moment  had 
arrived. 

We  connected  the  wire  to  the  last  bind- 
ing post  and  gave  the  belt  a  push — nothing 
happened.  We  gave  it  a  harder  push — an 
ominous  quietude.  What  could  be  wrong? 
Ah,  of  course,  oil !  Mother's  can  of  sew- 
ing machine  oil  was  promptly  secured  and 
soon  the  dynamo  and  motor  were  drown- 
(Continued  on  page  280) 


AMONG  the  hundreds  of  new  devices  and  appliances  publisht  monthly  in  The  Electrical  Experimenter,  there  are  several,  as 
a  rule,  which  interest  you.    Full  information  on  these  subjects,  as  well  as  the  name  of  the  manufacturer,  will  be  gladly 
furnisht  to  you,  free  of  charge,  by  addressing  our  Technical  Information  Bureau. 


250 


THE  ELECTRICAL  EXPERIMENTER 


August,  1917 


Experimental  Physics 

By  JOHN  J.  FTJRIA,  A.  B.,  M.  A. 

Instructor  in  Physics  and  Science  Master.  Riverdale  Country  School 


LESSON  6. 
Newton's  Laws. 

THE  branch  of  Physics  known  as 
Mechanics,  of  which  Statics  and 
Dynamics  are  subdivisions,  is  con- 
ceded by  scientists  to  be  the  founda- 
tion for  all  Physical  Science  if  not 
of  Science  as  a  whole.  Mach,  in  his  "Science 


ard 
the 
re- 


•n^H^vi^^SS^S    — -=  

A  Simple  Example  of  "Inertia."     If  the  C; 
Is  Snapt  by  the  Finger  it  Will  Fly  Off,  1 
Coin  Dropping  Directly  Underneath  Its  P 
vious  Position. 


of  Mechanics,"  says  that  since  the  time  of 
Newton  no  essentially  new  principle  has 
been  stated  but  that  all  that  has  been  accom- 
plisht  has  been  a  deductive  formal  develop- 
ment of  Mechanics  on  the  basis  of  New- 
ton's Laws.  The  man  who  establisht  this 
basis  two  centuries  ago  was  a  truly  great 
man  if  during  all  these  years  of  excellent 
scientific  research  and  discovery,  no  essen- 
tially new  principle  has  been  stated. 

Sir  Isaac  Newton  was  born  in  1642,  which 
was  the  year  in  which  the  great  Galileo 
died.  While  a  boy,  Newton  spent  a  great 
deal  of  his  time  in  constructing  many 
mechanical  toys.  He  didn't  like  school,  and 
since  he  stood  at  the  bottom  of  his  class  in 
scholarship,  his  teachers  didn't  like  him. 
His  thoughts  instead  of  being  on  his  school- 
work,  were  usually  on  other  worlds  than 
ours.  Not  being  very  healthy  and  being 
considered  a  dunce,  he  was  bullied  by  the 
other  boys.  He  stood  for  this  as  long  as 
he  could,  and  suddenly  one  day  he  "got 
mad  and  beat  up  the  bull}',"  who  was  first 
in  athletics  and  scholarship.  In  his  anger 
he  developed  great  strength,  and  he  himself 
was  more  surprised  than  anyone  else  to 
see  the  licking  be  gave  the  bully.  That 
night  he  decided  that  if  he  could  beat  up 
the  strongest  boy  in  the  class  he  could 
also  study  and  beat  him  intellectually. 
Henceforth  Newton  stood  at  the  head  of 


A  Nifty  Mexican  Game.  The  Idea  Is  to 
Knock  Out  Each  Block  One  by  One,  Finally 
Leaving  the  "Head"  A,  on  the  Table  and 
in  the  Same  Vertical  Line.    "Inertia"  Again. 


his  class  and  was  never  bullied  again. 
Therefore,  my  friends,  if  you  find  that  you 


are  at  the  bottom  of  the  clasr  or  not  up  at 
the  very  top,  beat  up  the  strongest  bully 
of  the  class  and  then  study  hard  and  get 
first  place,  and  perhaps  you  will  be  second 
Newtons.  While  an  undergraduate  at 
Trinity  college  he  studied  the  works  of 
Galileo,  Huygens  and  Keplar,  became  in- 
terested in  mathematics  and  physics,  and 
paved  the  way  to  his  great  future  contri- 
butions to  those  sciences.  At  his  death  in 
1727,  he  left  those  sciences  establisht  on  a 
firm  foundation.  He  was  a  great  scholar, 
not  only  in  his  field,  but  also  in  the  Clas- 
sics and  hence  we  are  not  surprised  to  find 
his  great  work  the  immortal  " Principia" 
written  entirely  in  the  Latin  language. 

Among  his  many  contributions,  and  first 
in  importance,  was  his  formulation  of  what 
are  known  as  Newton's  Three  Laws  of 
Motion.    He  stated  them  as  follows  : 

LAW  I.  Every  body  perseveres  in  its 
state  of  rest  or  of  uniform  motion  in  a 
straight  line,  except  in  so  far  as  it  is 
compelled  to  change  that  state  by 
imprest  forces. 

LAW  II.  Change  of  motion  (i.  e., 
momentum)  is  proportional  to  the  mov- 
ing force  imprest  and  takes  place  in  the 
direction  of  the  straight  line  in  which 
such  force  is  imprest. 

LAW  III.  Reaction  is  equal  and  op- 
posite to  action;  that  is  to  say,  the  actions 


Illustrating  "Action"  and  "Reaction."  With 
Board    "A"    Removed    the    Fan    Propels  the 
Wagon;  With  "A"  in  Place  the  Wagon  Stands 
Still. 


of  two  bodies  upon  each  other  are  al- 
ways equal  and  directly  opposite. 

Among  Newton's  definitions,  these  two 
are  of  especial  importance  in  connection 
with  his  laws  of  motion: — 

DEFINITION  II.  Quantity  of  mo- 
tion is  the  measure  of  it  by  the  velocity 
and  quantity  of  matter  conjointly. 

DEFINITION  III.  The  resident 
force  (i.  e.,  the  inertia)  of  matter  is  a 
power  of  resisting,  by  which  every  body, 
so  far  as  in  it  lies,  perseveres  in  its  state 
of  rest  or  of  uniform  motion  in  a  straight 
line. 

These  laws  are  to  be  regarded  as  axioms 
incapable  of  rigorous  experimental  proof. 
The  most  powerful  argument  for  their 
validity  rests  on  the  fact  that  their  applica- 
tion to  the  solution  of  problems  in  Physics 
and  Astronomy  leads  to  results  that  always 
agree  with  those  of  observation.  For  ex- 
ample, the  time  for  a  coming  eclipse  is  cal- 
culated by  assuming  the  truth  of  these  laws 
and  the  remarkable  agreement  between  the 
calculated  time  and  the  subsequent  ob- 
served time  confirms  the  laws. 


EXPERIMENT  31— Take  a  ride  in 
the  subway.  You  will  notice  that  the 
company  very  generously  furnishes  straps 
to  hang  on.  Newton's  Laws  are  respon- 
sible for  making  the  company  adorn 
its  trains  with  straps.  (If  you  live  out- 
side the  city  and  have  not  had  the  oppor- 
tunity of  riding  on  the  straphanger's  route, 
by  all  means  take  the  first  train  for 
the  city  and  enjoy  this  "pastime".)  The 


By  Means  of  Thumb-Tacks,  a  Baseball  Is 
Suspended  as  Shown.  Pulling  Suddenly  on 
Thread  at  "A",  it  Breaks  Between  "A"  and 
Pin  "B":  Pulling  Slowly  the  Thread  Parts 
Between  "C"  and  "D". 

bodies  in  the  moving  train  tend  to  move 
toward  the  rear  of  the  train  when  the  train 
starts,  and  toward  the  front  of  the  train 
when  the  train  stops.  This  serves  to  illus- 
trate Newton's  first  law,  that  a  body  in  mo- 
tion tends  to  keep  in  motion  and  that  a 
body  at  rest  tends  to  stay  at  rest.  (This 
experiment  is  apt  to  prove  unsuccessful  if 
tried  during  the  rush  hour,  when  we  are 
packed  so  tight  that  we  cannot  move.)  If 
the  train  should  turn  a  curve  while  in  rapid 
motion  we  are  thrown  into  the  lap  of  a 
pretty  young  girl  or  (if  we  are  sitting) 
said  young  girl  falls  into  our  lap  and  we 
are  duly  thankful  for  Newton's  first  law 
in  either  case. 

EXPERIMENT  32— If  father  should 
be  after  you  for  having  gone  to  the 
ball  game  instead  of  to  school  (he 
having  seen  you  by  going  to  the  game  in- 
stead of  to  work),  run  into  the  dining  room 
and  grasp  the  rug  firmly  in  both  hands. 
As  he  enters  the  threshold,  pull  the  rug 
and  he  will  sit  down  on  the  floor  in  great 
haste,  thus  giving  you  ample  time  to  es- 
cape. This  is  a  case  of  the  First  Law — 
Pa's  body  tended  to  stay  at  rest  while  you 
pulled  his  feet  from  under  him. 

EXPERIMENT  33— Another  interest- 
ing phase  of  this  experiment,  which 
you  can  try  on  a  good  friend  (pre- 
ferably one  who  can't  lick  you),  is  as 
follows  :  Ask  your  friend  to  place  his  right 
foot  behind  and  to  the  left  of  his  left 


Several    Interesting    and    Easily  Performed 
Experiments    to    Demonstrate'  the    Law  of 
Centrifugal  Force. 

foot.  Then  let  him  place  a  long  pole  or 
broomstick  on  his  right  toe,  holding  the 
pole  loosely  in  his  left  hand.  Count  three 
slowly  and  have  him  kick  out  rapidly  at 
the  word  three  to  see  how  far  he  can  send 
{Continued  on  page  281) 


August,  1917 


THE  ELECTRICAL  EXPERIMENTER 


251 


a*  RADIO  LEAGUE 


^AMERICA 


H.  Gernsback,  Manager 


HONORARY  MEMBERS 
CAPT.  WH.G  BULLARD.  U.  SN.     NIKOLA  TESLA 
PROF  REGINALD  FESSENDEN     DR  LEE  DE  FOREST. 

W.  H.  Kirwan,  Master  of  Radio  Relays 


Mr.  Amateur,  This  Means  You, 


By  THE  EDITORS 


THERE  are  still  a  few  amateurs  scat- 
tered over  the  country,  who  fail  to 
comprehend  that  this  nation  is  now 
engaged  in  the  most  stupendous  war 
the  world  has  ever  known. 
Being  at  war  is  a  mighty  serious  business 
and  it  is  not  good  patriotism  for  a  few 
thousand  disgruntled  amateurs  to  pass 
judgment  upon  our  government.  Whether 
we  think  that  the  Navy  Department  acted 
wisely  or  not  in  depriving  us  of  our  sta- 
tions, is  of  small  concern  to  the  nation  at 


in  order  to  get  in  touch  with  them  and  keep 
their  interest  in  wireless  alive.  Reason : 
The  government  needs  lots  of  operators. 
It  will  get  most  of  them  from  the  amateur 
ranks.  Yes,  perhaps  you  don't  believe  it, 
but  the  Government  is  with  us  now,  not 
against  us. 

We  think  we  will'have  some  good  news 
for  you  next  month.  Don't  think  that  we 
are  asleep,  and  if  some  of  you  have  given 
up  the  ship,  the  Editors  have  NOT.  So 
watch !  The  telegram  and  the  letter  repro- 
duced here- 


POSTAL  TELEGRAPH  -  COMMERCIAL  CABLES 


mm 


OOTTOrt CKCHANCE 

NEW  YOltK'CITV 
FHONC  Bit  HASOVCH 


TELEGRAM 


99KS  MJ  346P  41  GOVT 
TOPEKA  *S  JUNE  1 6  17 
EDITOR  ELECTRICAL  EXPERIMENTER 

223  'ULTON  ST  NY 
RADIO  COMPANY  KANSAS  NATIONAL  GUARD  NEEDS  TEN 


V 


COMMERCIAL  RADIO  OPERATORS 


with  speak 
volumes  to 
any  amateur 
who  wants  to 
see  the  light. 
Amateurs, 
GOOD  AMA- 
TEURS, not 
Hams,  are 
wanted  more 
than  ever. 

It's  up  1 0 
you  if  yon 
prefer  the 
trench  to  the 


dible  in  your  receiving  apparatus.  This 
makes  for  efficiency,  as  very  careful  and 
sharp  tuning  is  necessary.  Besides  it  is  not 
against  the  law,  and  also  it  keeps  you  in 
trim. 

Next  month  we  will  have  a  lot  of  new 
stunts,  "Illicit  to  do  with  your  Radio  Out- 
fit." Several  thousand  suggestions — some 
very  good  ones — have  already  been  re- 
ceived. 

In  the  meanwhile,  "don't  give  up  the  ship." 
As  "Fips,"  our  dear  office  boy,  was  wont  to 
say :    "It's  an  ill  wind  that  has  no  silver 


Immg 


I" 


ALL  RADIO  AMATEURS 
ATTENTION! 

The  Navy  Department  has  been  dele- 
gated by  our  President  to  close  all  ama- 
teur or  experimental  radio  stations,  no 
matter  whether  equipt  for  transmitting  or 
receiving,  licensed  or  unlicensed,  and 
therefore  we  shall  all  have  to  abide  by  this 
decree,  whether  we  like  it  or  not. 

Therefore,  "THE  ELECTRICAL  EX- 


PLEA8E  FURNISH  NAMES  ANO  ADDRESSES  SUCH  OPERATORS  IN  THIS  SECTION 
OF  COUNTRY  REPLY  MY  EXPENSE       BY  NIGHT  LITTER 

ADJUTANT  CENERAL  0F  KANSAS 


The  Radio  Amateurs  Who  Think  That  All  Opportunities  to  Do  Something 
Worth  While  Have  Ceased  Will  Do  Well  to  Note  the  Accompanying  Official 
Recognition  of  the  Service  Which  the  Radio  League  of  America  Will  Be 
Called    Upon    to    Furnish    Right    Along.    The    Moral    Is    Mr.    Amateur — 

"Prepare!" 


large.  At  any  rate,  the  facts  are  that  we 
can't  use  our  outfits  the  same  as  before, 
and  being  placed  in  this  position,  we  must 
try  and  make  the  best  of  it,  as  good  and 
law  abiding  Americans  should  do. 

On  the  other  hand,  we  should  show  a 
little  more  spunk  than  we  have  shown  dur- 
ing the  past  three  months.  It  is  decidedly 
un-American  to  "chuck  up"  our  hands  and 
say :  * 

"Oh,  well,  what's  the  use.  Wireless  is  as 
dead  as  the  Dodo.  •  Forget  it !" 

And  this  is  just  what  a  few  chicken- 
hearted  Amateurs  have  been  doing.  Luck- 
ily our  reports  show  that  their  numbers  are 
far  from  large.  Things  are  beginning  to 
shape  themselves  nicely.  The  situation  is 
becoming  rapidly  better ;  there  is  a  light 
gray  mist"  where  last  month  there  was  noth- 
ing but  inky  darkness.  The  Navy  begins  to 
see  that  the  curbing  of  Amateur  Wireless 
has  proved  a  boomerang.  Operators  are 
becoming  scarcer  than  hen's  teeth,  and  we 
need  countless  thousands  of  good  operators. 
How  to  get  them  quick?  In  Philadelphia  the 
Navy  Department  a  few  weeks  ago  took 
over  a  private  wireless  school  in  order  to 
speed  things  up.  As  we  go  to  press  a  gov- 
ernment official  calls  on  us  asking  for  a  list 
of  all  New  York  and  vicinity  Radio  Clubs 


Radio  tent  behind  the 
lines.  You  can  be  heroic 
and  manly  in  either. 
Which  do  you  choose? 
But  you  must  know  your 
business,  and  if  you  are 
a  "ham"  now,  go  to  some 
good  radio  school  or  if 
you  cannot  do  this  take 
a  correspondence  school 
course.  Then  again  as  a 
beginner,  you  can  drill  at 
home  at  little  or  no  cost. 
There  are  a  number  of 
good  instruments  with 
which  to  learn  how  to 
send  and  how  to  receive 
the  code.  In  less  than  ' 
three  months  you  can  be 
an  expert  in  sending  and  in  receiving,  with 
an  outfit  operated  right  at  home.  An  hour 
a  day  suffices.  If  you  have  a  radio  outfit, 
keep  it  in  good  trim,  even  if  you  can't  con- 
nect it  to  an  aerial.  After  that  go  to  a 
good  radio  school  and  "brush  up."  Also 
with  a  simple  buzzer  arrangement,  you  can 
send  yourself  messages,  using  your  receiv- 
ing apparatus,  and  no  aerial.  A  muffled  or 
silent  buzzer  along  side  of  you  will  send  out 
sufficient  waves  across  the  table,  to  be  au- 


STATE  OF  KANSAS 
ADJUTANT  GENERALS  DEPARTMENT 


June  25,  1917. 


H.  Gernsbaok  ,Edi tor. 
The  Electrical  E*periro?nter, 
233  Fulton  street. 
New  York,  H.  1. 


Dear  Sir: — 


Kindly  accept  my  thanks  for  your  kindness  In  furnishing  me 
With  the  names  of  radio  operators  in  tills  section  of  the  country. 


As  a  part  of  the  troops  alloted  to  Isnsas  by  the  War  Depart- 
ment I  was  authorised  to  organize  a  battalion  of  Signal  troops 
consisting  of  one  wire  conpany,  one  radio  conpany  and  one  outpost 
compeny.     Each  Company  comprising  seventy-five  enlisted  men  and 
of  ucers.     In  the  organization  of  the  radio  conpany  which  is 
stationed  at  Topeka  I  was  advised  by  the  .'ar  iiepartment  that  at 
least  ten  Conns roial  Radio  operators  should  be  inoluded  in  the 
membership  of  the  company.     1  an  not  quite  clear  as  to  whether  the 
term  "comrercial  radio  operators"  as  used  by  the  v/ar  Department  is 
intended  to  cover  only  licensed  Comrercial  operators,  or  operatorf 
who  are  oapable  of  handling  Comrercial  business  but  has  not  been 
granted  their  Commercial  Radio  lloenses. 


Captain  Elmer  5.  stahl,  Topeka,  am, as,  is  cemwanding  officer  of 
the  Radio  Convoy,  and  it  Is  probable  that  Captain  Stahl  and  the  lum- 
bers of  his  organisation  would  be  interested  In  eleotrioal  and  radio 
publications  published  by  your  Company.     I tJ might  be  well  to  send  him 
a  list  of  sncb  publications  and  possibly  a  catalogue  of  apparatus. 

Yours  very  truly. 
The  Adjutant  General. 


PERI  M  ENTER,"  will  endeavor  to 
feature  the  Electrical  Laboratories  in 
preference  to  any  radio  stations  in  the 
awarding  of  the  monthly  prize  of  $3.00  in 
this  department.  Now  is  the  time  to  get 
busy  and  freshen  up  your  electrical  ap- 
paratus, and  incidentally  improve  your 
understanding  of  electrical  matters,  which 
perhaps  you  have  unwittingly  slighted  to 
a  large  degree  in  your  pursuit  of  radio- 
telegraphy.    Let  her  go,  boys! 


252 


THE  ELECTRICAL  EXPERIMENTER 


August,  1917 


Bell  Telephone  Engineers  in  U.  S.  Signal  Reserve  Corps 


THE  Signal  Corps  forms  one  of  the 
most  important  divisions  of  any 
army.  The  U.  S.  Signal  Reserve 
Corps  have  had  the  good  fortune  to 
enlist  in  their  ranks  some  of  the 
best  telephone,  telegraph  and  radio  engi- 
neers in  the  country.  The  extensive  and 
ever  progressive  Bell  Telephone  System  has, 
among  numerous  other  worthy  accomplish- 
ments, developed  a  particularly  efficient 
engineering  staff,  comprising  thousands  of 
men,  practically  all  college-trained  and  men 
who  have  proven  ability  in  these  now  su- 
premely important  branches  of  applied 
electricity.    This  widespread  organization 


received  the  approval  of  the  Army  au- 
thorities. 

In  March,  1917,  the  detailed  plan  was 
presented  to  the  employees  of  the  Bell  Sys- 
tem thruout  the  country,  with  an  oppor- 
tunity given  all  men  from  eighteen  to  forty- 
five  years  old  to  volunteer. 

Mr.  J.  J.  Carty,  chief  engineer  of  the 
American  Telephone  and  Telegraph  Com- 
pany, had  received  his  commission  from 
President  Wilson  as  senior  major,  and 
twenty-five  Signal  Corps  Reserve  com- 
panies were  to  be  formed  from  the  Bell 
operating  companies,  each  company  to  be 
made  up  of  one  captain,  two  first  lieutenants 


A  Group  of  Future  U.  S.  Signal  Reserve  Corps  Engineers  Receiving  Instruction  in  the  Engineers'  Conference  Room, 
American  Telephone  and  Telegraph  Co.,  New  York  City. 


has  had  not  only  the  problem  of  furnishing 
trained  officers  and  men  to  the  Signal  Re- 
serve Corps,  but  also  to  face  the  gigantic 
task  of  maintaining  its  nation-wide  lines  of 
communication  which  it  had  built  up. 

The  presidents  of  the  various  Bell  Com- 
panies thruout  the  United  States  at  a  con- 
ference held  in  New  York  in  November, 
1916,  approved  a  plan  which  had  previously 
received  the  approval  of  the  directors  of 
the  American  Telephone  and  Telegraph 
Company,  to  encourage  the  formation  from 
the  telephone  companies'  personnel  of  a 
reserve  of  officers  and  men,  in  accordance 
with  the  provisions  of  the  National  De- 
fense Act  of  June  3,  1916.    This  plan  had 


and  an  average  of  about  one  hundred  non- 
commissioned officers  and  men,  with  one 
major  and  an  extra  lieutenant  (his  adju- 
tant) for  each  two  companies,  a  total  of 
about  one  hundred  officers  and  2,500  non- 
commissioned officers  and  men. 

The  New  York  Telephone  Company  was 
to  provide  five  of  these  companies.  A  total 
of  2,871  volunteered.  Two  companies  have 
been  formed  from  the  Manhattan-Bronx 
and  Westchester  Divisions,  one  from  the 
Long  Island  Division,  one  from  the  New 
Jersey  Division,  and  one  from  the  Albany- 
Syracuse-Buffalo  districts. 

In  addition  a  number  of  the  engineers  of 
the  Western  Electric  Company  have  been 


commissioned  in  the  Signal  Officers  Re- 
serve to  do  special  development  and  research 
work  in  connection  with  wireless  and  other 
systems  of  communication.  Maj.  F.  B. 
Jewett  is  the  ranking  officer  in  charge  of 
this  work  and  will  be  stationed  in  New 
York.  Maj.  N.  H.  Slaughter  is  in  direct 
charge  of  the  radio  development  work  in 
Washington,  where  he  will  have  a  separate 
organization  reporting  to  him,  which  he  is 
now  engaged  in  organizing. 

As  war  with  Germany  had  not  been  de- 
clared when  the  plan  was  put  into  effect, 
provision   was  made   for  employees  who 
joined  the   Signal   Reserve  Corps  during 
times  of  peace,  as  well 
as  in  times  of  actual  or 
threatened  hostilities. 
The  following  regula- 
tion is  in  force  since 
the  country  is  now  at 
war : 

Leaves  of  absence  will 
be  granted  to  such  em- 
ployees when  ordered  to 
duty  by  the  President  of 
the  United  States  in  time 
of  actual  or  threatened 
hostilities.  Such  leaves 
of  absence  will  be  subject 
to  the  following  condi- 
tions: 

"(a)  The  leave  will 
cover  the  period  of 
the  employee's  neces- 
sary absence  on  such 
duty  during  the  re- 
mainder of  the  term 
of  the  commission  or 
enlistment  under 
which  he  is  serving 
at  the  time  he  is 
ordered  to  duty,  and 
during  renewals 
thereof  in  time  of 
war. 

"(b)    The  employee  will 
be  allowed  full  pay, 
at  the  normal  rate  in 
effect    when    he  is 
ordered  to  duty,  until 
the  end  of  the  calen- 
dar month  in  which 
he  is  thus  called  into 
service;  thereafter, 
for    the     period  of 
leave  of  absence,  but 
not  exceeding  twelve 
months,  he  will  be  al- 
lowed full  pay  at  such 
normal  rate  less  the 
amount  which  he  is 
entitled    to  receive 
from     the  Govern- 
ment.    If  the  neces- 
sary absence  on  duty 
continues  beyond 
such  twelve  months, 
further  consideration 
will  be  given  to  the 
matter   of  payment. 
"(c)    The  employee  will  retain  his  eligibility  to 
benefits  under  the  'Plan  for  Employees'  Pen- 
sions, Disability  Benefits  and  Death  Benefits' 
during  the  period   of  leave  of  absence,  and 
such  period  of  absence  will  not  be  deducted 
in    computing   his    term    of    employment  for 
purposes  of  said  Plan. 
"(d)    Upon  return  from  such  duty  (after  honor- 
able discharge  if  the  employee  has  left  the 
United  States  military  service),  the  employee 
will  be  given  such  employment  as  the  needs 
of  the  service  permit  and  as  he  is  able  and 
fitted  to  perform." 

These  officers  and  men  of  the  Bell  Sys- 
tem, trained  and  experienced  in  "the  art 
of  construction  and  maintaining  telephone 
and  telegraph  lines,"  have  been  accepted 
and  commissioned  by  the  Government,  and 
are  being  instructed  in  military  duties. 


August,  1917 


THE  ELECTRICAL  EXPERIMENTER 


253 


MEXICO  CITY  RADIO  MAY  REACH 
GERMANY. 

The  accompanying  photograph  shows  the 
new  wireless  station  erected  close  to  the 
Castle  of  Chapultepec  in  the  City  of  Mex- 
ico. The  Mexican  government  has  had  a 
wireless  station  at  that  point  for  several 


to  be  something  more  than  a  mere  "scrap 
of  paper." 

It  is  said  that  there  is  another  wireless 
station  in  Mexico  somewhere  near  Salina 
Cruz,  as  well  as  the  one  installed  between 
the  towers  of  the  parochial  church  in 
Tampico,  the  latter  having  been  trans- 
ferred from  the  interned  Ham- 
burg-American steamship  An- 
tonina  at  Tampico. 

It  is  known  that  Mexico  City 
has  been  holding  wireless  com- 
munication with  San  Salvador 
and  also  with  Colombia,  and  it 
is  also  known  that  the  German 
Minister  in  Havana  has  re- 
ceived mysterious  wireless  mes- 
sages having  to  do  with  Mexi- 
can affairs. 


rolled  in  the  Signal  Corps  of  the  students' 
battalion  and  are  receiving  instruction  in 
wireless  work.  Experienced  drill  sergeants 
are  needed  at  once  for  the  University  bat- 
talion, in  which  nearly  2,000  students  have 
enrolled.  Men  who  have  had  experience 
in  military  schools,  the  National  Guard  or 
the  regular  service  will  be  accepted,  and 
will  be  on  duty  each  afternoon  from  1  to 
6  o'clock.    The  pay  is  $45  a  month. 


Photo  from  New  York  Herald. 

One  of  the  Gigantic  Steel  Radio  Masts,  Each  410  Feet 
High,  in  Mexico  City.    This  Plant  It  Is  Thought  Can  Easily 
Communicate  With  Germany. 

years,  but  it  was  practically  useless,  be- 
cause, it  was  said,  the  towers  for  the  aerials 
were  not  high  enough.  They  were  85 
meters  high,  or  about  278  feet.  Recently 
the  towers  have  been  made  higher.  They 
are  now  125  meters  high,  or  410  feet,  and 
one  of  these  towers  is  shown  in  the  ac- 
companying photograph.  The  other  tower 
is  not  in  the  picture,  but  the  supporting 
stay  wires  leading  to  its  top  may  be  plainly 
seen  to  the  right. 

While  this  wireless  station  is  owned  and 
operated  by  the  Mexican  government,  it 
is  common  talk  in  Mexico  City  that  the 
recent  additions  and  improvements  have 
been  made  possible  by  German  capital  and 
that  the  station  is  of  far  greater  value  to 
the  Germans  than  to  the  Mexican  govern- 
ment. Mexico,  it  is  indicated,  has  no  mer- 
chant marine  and  practically  no  navy,  so 
that  the  erection  of  an  expensive  wireless 
station  at  the  capital  would  seem  to  be  a 
useless  and  superfluous  luxury. 

A  Mexican  account  says  "that  the  wire- 
less station  installed  at  Chapultepec  has 
been  communicating  directly  with  the 
North  American  city  of  Houston,  in  the 
State  of  Texas,  and  with  some  cities  of 
South  America,  especially  Panama. 
"This  fact  signifies  that  our  wireless  ser- 
vice is  improving  daily  and  that  its  field  of 
action  is  extended  more  and  more." 

The  inspired  "explanation"  of  why  Mex- 
ico has  suddenly  added  such  a  powerful 
station  to  its  wireless  service — to  be  pre- 
pared to  report  merchant  ships  after  the 
war  ends  in  Europe — has  been  received  with 
some  amusement  by  foreigners  who  read 
it  in  Mexico  City  in  the  government  or- 
gan. It  was  commented  that  the  station 
might  be  of  far  greater  value  to  German 
submarines  in  Gulf  waters  if  possibly  the 
Zimmerman  note  inviting  Mexico  to  be- 
come an  ally  of  Germany  should  prove 


MOST  ANYTHING 
SERVES  EXPERT  FOR 
A  WIRELESS. 

The  police  at  the  Second 
Precinct  station  in  Cleveland, 
O.,  recently  received  an  im- 
promptu lesson  in  wireless  that 
curled  their  hair  and  left  them 
wondering. 

A.  D.  Silva,  equipment  ex- 
pert, was  taken  to  task  because 
police  thought  he  had  not  dis- 
mantled his  wireless  plant  in 
compliance  with  the  President's 
order. 

"But  I  took  down  my  aerial," 
protested  Mr.  Silva. 

"Won't  do — you  must  take 
your  instruments  off  the  table 
— put  them  out  of  commission," 
explained  the  police. 

"But  I  can  sit  right  here  in 
this  room,  and  with  materials 
you  see  on  this  desk  I  can  make 
an  outfit  with  which  I  can  re- 
ceive from  a  distance  of  200 
miles,"  said  Mr.  Silva. 

Whereupon  he  took  the  sergeant's  safety 
razor  blades,  a  pencil,  a  telephone  receiver, 
some  wire  and — (deleted  by  censor) — gave 
a  demonstration  that  proved  so  interesting 
that  it  lasted  for  two  hours. 

"Or  one  could  do  the  same  with  clock 
parts — if  he  knew  how,"  said 
Mr.  Silva. 


KEEP  UNIV.   OF  PENN. 
WIRELESS  OPEN. 

Permission  has  been  granted 
the  University  of  Pennsylvania 
by  the  Government  to  keep  its 
wireless  station  open  for  the 
receiving  of  messages,  but  no 
messages  will  be  sent.  Eight 
members  of  the  wireless  class 
have  agreed  to  watch  the  ap- 
paratus to  prevent  tampering 
with  the  station  and  to  pick  up 
any  enemy  messages  that  might 
be  sent  from  hidden  wireless 
plants  nearby. 

In  the  past  two  weeks  thirty- 
two  undergraduates  have  en- 


OSCILLATORY  DISCHARGES. 

Ten  little  coulombs  looking  jolly  fine, 
One  was  discharged,  and  then  there  were 
nine. 

Nine  little  coulombs  made  to  oscillate, 
One  jumped  a  spark  gap,  and  then  there 
were  eight. 

Eight  little  coulombs  sent  off  to  heaven, 
One  became  earthed,  and  then  there  were 
seven. 

Seven  little  coulombs  playing  funny  tricks, 
One  strained  the  ether,  and  then  there 
were  six. 

Six  little  coulombs  looking  quite  alive, 
One  got  damped,  and  then  there  were  five. 

Five  little  coulombs  feeling  somewhat  sore, 
One  got  resisted,  and  then  there  were  four. 

Four  little  coulombs  in  a  battery, 
Someone  switched  the  current  on,  and  then 
there  were  three. 

Three  little  coulombs  wondering  what  to 
do, 

One  got  polarized,  then  there  were  two. 

Two  little  coulombs,  after  all  this  fun, 
One  caught  hysteresis,  and  then  there  was 
one. 

One  little  coulomb,  feeling  rather  glum, 
He  was   short-circuited,   then  there  was 
none. 

— R.  C.  D.,  in  Wireless  World. 


"How  to  use  your  radio  instru- 
ments for  short  range  communica- 
tion without  aerials  (sending  and 
receiving)"  is  the  title  of  an  article 
to  appear  in  the  September  "E.  E." 
Don't  miss  it,  "Radiobugs!" 


THIS  RADIO  MAST  RESEMBLES 
EIFFEL  TOWER  ON  WHEELS. 

Herewith  is  pictured  one  of  the  new- 
est inventions  for  military  purposes.  It 
is  a  portable  wireless  telegraph  outfit, 
mounted  on  top  of  a  fast  automobile. 
The  transmitting  and  receiving  appa- 
ratus is  connected  to  a  latticed  steel  aerial 
tower  which  looks  like  a  miniature  Eiffel 
tower  and  has  a  hinged  top  which  may 
be  raised  and  lowered  as  desired.  The 
contrivance  attracted  much  attention 
when  it  was  recently  driven  about  the 
streets  of  New  York  City. 

It  is  possible  to  transmit  and  receive 
radio  messages  while  the  car  is  moving 
at  any  speed.  It  is  intended  to  be  fitted 
with  machine  guns  and  may  serve  as  an 
elevation  from  which  to  signal  by  wig- 
wag flags  or  by  heliograph. 


v.. 


Photo  by  American  Press  Association. 

The  Newest  Combined  Radio,  Signal  and  Observation  Tower  Mounted  On  Fast  Auto  Truck, 
Which  Is  Being  Used  By  U.  S.  Signal  Corps. 


254 


THE  ELECTRICAL  EXPERIMENTER 


August,  1917 


The  Amateur  and  Experimental  Radio  Research 


WE  may  bring  radio  research  work 
under  two  general  captions.  (1) — ■ 
That  involving  the  electrical  and 
mechanical  design  of  instruments 
without  changing  the  theoretical 
principle.      (2) — That    involving    the  de- 


An  Experimental  Poulsen  Arc  Will  Prove  Extremely  Valuable 
for  All  Classes  of  Radio  Measurements  and  Tests  with  Dummy 
Antennae.  This  Piece  of  Apparatus  Should  Be  Found  in  Every 
Radio  Experimenter's  Laboratory.  It  is  Provided  with  Gas 
Jacket  and  Water  Cooled  Anode. 


sign  of  apparatus  that  operates  on  a  new 
theoretical  principle.  During  the  past  few 
years,  many  new  instruments  have  been  in- 
vented that  would  come  under  the  first 
classification.  We  have  seen  scores  of  new 
detectors,  tuning  transformers,  variable  con- 
densers— et  cetera,  that  possess  the  same 
basic  principle  of  operation  but  differ  only 
in  mechanical  design.  In  many  cases,  the 
manufacturers  permit  novelty  of  design  to 
interfere  with  the  most  efficient  construc- 
tion of  the  instrument,  and  this  is  indeed 
a  mistake.  There  is  much  in  the  design  of 
an  instrument,  but  novelty  plays  the  small- 
est part.  Those  experimenters  who  wish  to 
invent  new  designs  should  first  assure  them- 
selves that  their  new  design  will  give 
greater  satisfaction  in  either  one  of  the 
following  ways;  i.  e.,  efficiency,  (first  and 
foremost),  economical  construction  with- 
out loss  of  efficiency,  and  convenient  man- 
ipulation. The  design  of  instruments  forms 
a  very  lucrative  field  of  research  and  ex- 
periment for  the  amateur  and  it  is  indeed 
encouraging  to  see  that  many  amateurs  in 
the  United  States  have  invented  new  in- 
struments of  merit  and  practicability. 
Eugene  V.  Turney  of  New  York  City  offers 
a  splendid  example  of  the  work  experi- 


By  RAYMOND  FRANCIS  YATES 
Part  II — Suggestions  for  Research  Work 

menters,  who  possess  a  little  originality, 
can  do  in  the  way  of  new  designs.  If  an 
instrument  can  be  built  more  cheaply,  func- 
tion more  accurately  or  efficiently,  or  made 
easier  to  manipulate,  it  can  find  a  place  of 
ready  sale  on  the  market  and  its  inventor 
will  be  well  paid  for  his 
effort,  both  in  money  and 
in  distinction  for  advan- 
cing the  art.  The  man 
that  found  that  comprest 
air  was  preferable  to 
glass  as  a  di-electric  in 
condensers  discovered  a 
new  principle  of  great 
importance,  yet  most  any 
amateur  could  have  made 
the  same  discovery. 

We  find  very  few  new 
instruments  on  the  mar- 
ket that  operate  on  a  new 
basic  or  theoretic  prin- 
ciple. There  are  many 
cases  where  an  instru- 
ment can  be  designed  so 
that  it  will  accomplish  a 
certain  function  by  a  dif- 
ferent fundamental  prin- 
ciple. The  Audion  is  a 
good  illustration.  It  is 
a  substitute  for  an  or- 
dinary detector  that  not 
only  operates  on  a  new 
principle,  but  performs 
its  part  more  efficiently. 
There  are  many  instru- 
ments that  would  per- 
form more  efficiently  on 
different  principles. 
Thus,  the  quenched 
spark  gap  operates  dif- 
ferently than  the  rotary 
and  the  variometer  dif- 
ferently than  the  tuning 
transformer.  In  some 
cases,  mechanical  and 
electrical  design  are  so 
closely  related  that  we 
cannot  alter  one  without 
considering  the  other. 

Aside  from  the  inven- 
tion of  new  instruments 
and  the  discovery  of  new 
principles,  the  problem 
of  hook-ups  also  forms 
an  important  field  for 
wireless  research  work.  There  is  much 
in  the  method  of  connecting  a  wireless 
outfit  and  our  present  systems  are  as 
young  and  undeveloped  as  wireless  itself, 
and  it  is  only  logical  to  conclude  that, 
as  the  art  advances,  so  must  the  methods  of 
connections  and  many  important  changes 
will  take  place.  In  many  cases,  patents  may 
be  procured  on  wireless  hook-ups  and  if 
an  experimenter  really  discovers  a  method 
of  connection  that  increases  efficiency,  he 
may  protect  it  and  in  all  probability  realize 
something  from  it. 

Question — What  Is  There  to  Invent? 

The  room  for  improvement  is  so  great 
and  the  multitude  of  suggestions  so  vast 
that  it  would  indeed  take  a  volume  to  cover 
them.  In  the  following  we  will  outline  a 
few  of  the  more  important  and  popular 
problems  of  the  day. 

At  the  present  time  the  Audion  detector 
is  not  being  used  by  many  amateurs  be- 
cause it  is  too  expensive  to  operate,  due  to 
the  cost  of  the  flashlight  batteries.  Is  it 
not  possible  to  find  means  that  will  obviate 
the  necessity  of  using  a  high  potential  bat- 
tery? It  indeed  seems  very  reasonable 
that  the  basic  construction  of  the  Audion 


can  be  changed  to  accomplish  this  result. 
If  this  cannot  be  done,  why  not  invent  a 
"new"  Audion  that  will  possess  this  de- 
sirable feature?  Another  possibility  of  im- 
provement in  the  "Audion"  is  in  the  fact 
that  a  glowing  filament  is  not  the  only 
agency  that  will  produce  ionization  in  a 
vacuum.  If  some  other  agency  could  be 
utilized,  "Audions"  could  be  constructed 
that  would  last  forever. 

Another  conspicuous  problem  of  the  day, 
and  one  that  is  preventing  progress  in 
radio-telephony,  is  the  heavy-current  trans- 
mitter. At  first  thought,  this  is  a  seemingly 
simple  problem,  but  this  is  not  so,  as  many 
great  minds  have  worked  on  the  problem 
and  there  is  yet  a  great  fortune  in  store 
for  the  inventor  of  a  real  practical  ar- 
rangement. 

The  spark  gap  of  today,  whether  rotary 
or  quenched,  is  a  very  inefficient  instrument 
and  an  extravagant  user  of  energy.  Will  it 
ever  become  possible  to  make  a  circuit  os- 
cillate without  a  discharge  in  connection 
with  a  transformer?  If  such  a  discovery 
was  made,  the  high-frequency  alternator 
would  probably  never  need  to  be  perfected. 

While  the  high  aerial  today  forms  an  in- 
dispensable part  of  a  wireless  equipment, 
without  a  doubt,  it  will  be  entirely  obviated 
in  the  equipment  of  the  future.  At  the 
present  time  experiments  are  being  carried 
on  with  a  "concentrated"  aerial  and  it  has 
been  found  to  give  remarkable  results. 
The  "concentrated"  aerial  is  probably  the 
fore-runner  of  the  aerial  of  the  future.  It 
is  only  logical  to  conclude  that  the  aerial  of 
the  future  must  be  small,  for  at  that  time 
man  will  have  perfected  transmitting  in- 
struments to  such  a  degree  of  efficiency, 
and  brought  receiving  apparatus  to  such  a 
point  of  sensitivity,  that  the  large  and  lofty 
aerial  will  no  longer  be  necessary.  The 
question  today  is,  what  type  of  concentrated 
aerial  is  the  most  efficient?  This  is,  of 
course,   left  open  to   experimental  deter- 


The  Spark  Gap  of  To-day,  Whether  Rotary 
or  Quenched,  Is  a  Very  Inefficient  Instru- 
ment and  an  Extravagant  User  of  Energy. 
Why  Not  Try  to  Find  a  Substitute  for  It? 


mination.  When  we  realize  that  the  great- 
est item  of  expense  in  a  powerful  radio 
station,  is  the  aerial-supporting  towers,  we 
can    readily  conceive  what  an  important 


August,  1917 


THE   ELECTRICAL  EXPERIMENTER 


255 


question  it  really  is.  Man)'  may  be  in- 
clined to  say  that  it  is  too  early  to  experi- 
ment with  the  "concentrated"  aerial,  but 
this  is  not  so  as  that  degree  of  perfection 
in  radio  apparatus  is  so  rapidly  approach- 
ing that  this  type  of  aerial  will  soon  be  a 
necessity. 

Every  instrument  in  a  radio  equipment, 
no  matter  what  it  is,  represents  only  a  small 
degree  of  efficiency.  The  'phones,  con- 
densers, tuners,  detectors,  gaps  or  trans- 
formers are  all  in  the  embryo  state.  To 
obtain  suggestions  for  improvement,  the  ex- 
perimenter need  only  sit  down  at  his  instru- 
ments and  gaze  at  them,  at  the  same  time 
analyzing  each  one  and  asking  himself 
where  and  how  they  can  be  perfected. 

Methods  of  Attacking  Problems 

Before  entering  into  research  on  any 
special  subject,  the  experimenter  should  first 
properly  prepare  himself  in  what  may  be 
called  the  "preliminaries."  If  his  idea  con- 
cerns tuning  transformers,  he  should  not 
depend  wholly  upon  the  knowledge  he  al- 
ready has  in  connection  with  this  particular 
instrument,  but  should  go  further  and  make 
a  complete  study  of  it.  Every  available  bit 
of  literature  should  be  read.  Probably  the 
idea  has  been  tried  before,  or  it  may  be 
that  during  his  investigations  he  will  con- 
ceive of  a  better  way  to  accomplish  his  ob- 
ject. Above  all,  he  must  know  the  theory 
and  operation  of  the  instrument  he  is  con- 
cerned with.  Every  experiment  he  makes 
should  be  inspired  by  a  definite  conception 
of  the  circumstances  and  conditions  to  be 
involved  as  well  as  a  concrete  pre-deter- 
mination  of  the  result  being  sought.  An  ex- 
perimenter may  start  a  certain  investiga- 
tion with  an  isolated  idea  of  the  result  he 
wishes  to  obtain,  but  as  he  gets  into  the 
practical  research  work,  he  will  be  sur- 
prised to  find  that  his  idea  is  suffering 


ence"  on  the  other  side  of  the  continent. 

That,  however,  was  over  telephone  wires. 
To  play  the  piano  while  isolated  in  mid- 
ocean  and  have  the  notes  float  thru  the  air 
and  bring  pleasure  to  those  far  distant,  does 


K 


FEED  SCREW 


10-32 


POLE 


GAS 


evolution.     If  it  has  no  evolution,  some- 
thing is  wrong,  for  when  an  idea  is  put  to 
practical  test,   one  invariably  finds  many 
ways  of  improvement,  and,  in  many  cases 
these  are  so  numerous  and  severe  that  our 
later  conception  of  ob- 
taining the  desired  re- 
sults is  entirely  dif- 
ferent  from  the  one 
we  originally  possest. 
When    an  amateur 
gets    into  research 
work  and  feels  these 
circumstances  devel- 
oping, he  will  at  once 
find    his    interest  so 
keen  and  his  "invent- 
ing mood"  so  intense 
that  something  is  sure 
to  come  of  it,  as  his 
efforts  are  sure  to  be 
conscientious.  Re- 
search   work    is  the 
most  interesting  field 
o  f  endeavor 
open  today, 
and  it  is  safe 
to   say  that 
with  o  u  t 
proper  and 
rigid  investi- 
gation —  Rc- 
scarch  —  no 
important  in- 
vention will 
be  made. 
There  are  ex- 
ceptions to 
every  rule, 
but   it   is  in- 
variably true 
that,  we  can- 
not get  some- 
thing  for 
nothing. 

The  best 
paid  radio  and 
electrical  en- 
gineers to-day 
are  those  en- 
gaged in  re- 
search work,  sectional  View  of  V2  K.  W.  Experimental  Poulsen  Arc  for  Radio  Require- 
But  they  must  ments  (See  Opposite  Page  Also),  which  the  Radio  Student  Will  Find  Highly 
be  thoro  in  Interesting  and  of  Many  Uses  in  Various  Investigations  and  Tests.  It  Has 
their  knowl  Talked  Wirelessly  25  Miles.    Excitation  Is  By  Direct  Current. 

edge. 

much  toward  the  complete  annihilation  of 
space  and  causes  us  to  wonder  what  tomor- 
row may  bring  forth. 

When  we  are  far  from  home — and  think 
of  the  loved  ones  left  behind,  shall  we  be 
able  to  commune  with  them  thru  music  ? 


5PRING*I6  WIRE 


THUMB  NUT 


ASBESTOS 
GASKET ^ 


STD  2"  IRON  PIPE 


CARBON 
ROD 


SOLID 


ro+  POLE 


WATER  CHAMBER 


COPPER  ELECTROpE 

S=?--GAS  INLET 
£  PIPE 

-ASBESTOS 
^--SLATE 


WATER 
OUTLET 


PORCELAIN  J 
KNOB 


1%  O.D.  BRASS  TUBE 


3 


A   Common    Form    of   Step-up  Transformer 
Used  for  Radio  Transmitting  Purposes.  There 
Should    Be    Many    Opportunities   Offered  in 
This  Direction  for  New  Ideas. 


MUSIC  BY  WIRELESS 
Tina  Lerner's   Playing  on  Board  Ship 
Heard  on  Other  Vessels  500  Miles  Away 

Imagine  sailing  on  a  ship  in  mid-ocean 
and  being  able  to  hear  your  favorite  pianist 
in  a  concert  that  she  is  giving  on  board  a 
vessel  hundreds  of  miles  away !  The  pos- 
sibility is  not  so  remote  as  one  might  sur- 
mise, for  on  Washington's  birthday  last, 
Tina  Lerner,  the  distinguished  young  Rus- 
sian pianist,  gave  a  recital  on  board  the 
Ventura  on  her  homeward  journey  from 
Honolulu,  and  enjoyed  the  unique  thrill  of 
feeling  that  her  music  was  being  heard  by 
wireless  operators  on  board  passenger  and 
freight  steamers  as  far  as  500  miles  away. 

In  the  concert  room  where  Miss  Lerner 
was  playing,  a  transmitter  was  placed,  and 
by  means  of  a  recently  perfected  wireless 
telephone  apparatus,  the  music  was  sent  out 
over  a  large  radius. 

The  experience  of  listening  to  this  con- 
cert was  far  more  novel  than  participating 
in  the  demonstrations  which  have  recently 
been  tried  successfully,  when  singers  and 
speakers  in  San  Francisco  were  heard  at 
meetings  and  banquets  in  New  York  and 
other  cities.  At  these  functions  the  guests 
were  provided  with  telephones  thru  which 
they  heard  every  tone  distinctly.  Even  the 
applause  that  the  singers  received  on  the 
Pacific  Coast  was  accurately  transmitted, 
and  all  the  thrills  that  attended  the  real 
concert   were   felt   by   this    "proxy  audi- 


NAVY    RESERVE    WANTS  WIRE- 
LESS OPERATORS 

An  opportunity  for  amateur  wireless  op- 
erators having  a  knowledge  of  wireless  or 
land  telegraphy  to  join  the  navy  reserve 
force  was  announced  at  the  Great  Lakes 
training  station  at  Lake  Bluff  recently.  It 
was  stated  that  radio  operators  soon  will 
be  needed  and  that  facilities  for  giving  the 
instruction  have  been  provided  by  the  navy. 

Heretofore  the  number  of  radio  opera- 
tors who  responded  to  the  call  to  the  colors 
has  been  so  great  that  all  positions  were 
filled,  the  schools  of  instruction  were  over- 
crowded and  all  enlistments  in  the  branch 
had  to  be  stopt  until  further  arrangements 
could  be  made. 


PROF.  TAYLOR   DIRECTS   U.  S. 
RADIO. 

Professor  A.  H.  Taylor  of  the  physics 
department,  University  of  North  Dakota, 
was  recently  appointed  district  superinten- 
dent of  communication  at  the  Great  Lakes 
Training  Station.  He  is  a  radio  expert  and 
has1  been  given  the  rank  of  lieutenant  in  the 
Navy. 


THE  "ELECTRO"  CODOPHONE 


(Patents 

AMATEURS! 
ATTENTION!! 

Now  that  we  are  for  the  time  being,  deprived  of  using  our 
Radio  outfits,  it  behooves  us  as  good  Americans  to  become 
proficient  in  learning  the  Wireless  as  well  as  Telegraph 
Codes.  Operators  who  know  the  Code  are,  and  will  be,  in 
ever  rising  demand.  The  Army  and  Navy  need  thousands 
of  operators  right  now. 

So  far  the  Government  has  not  been  able  to  obtain  any 
way  near  all  the  operators  it  requires.  Not  alone  does  the 
Federal  Government  call  for  thousands  and  thousands  of 
operators  for  the  army  and  navy,  but  nearly  all  of  our  many 
states  require  operators  for  the 
militia.  Here  is  the  great  opportun- 
ity of  a  life  time  for  you. 

Would  you  rather  fight  in  the 
trenches,  or  punch  the  key  behind 
the  lines?  Either  way  you  benefit 
your  country.  Which  do  you  prefer? 
And  it  is  SO  easy  to  become  an  oper- 
ator. You  do  not  necessarily  require 
a  teacher,  nor  do  you  have  to  go  to 
a  school  to  learn.  30  days  of  intel- 
ligent study  will  make  you  proficient. 
Can  you  qualify  NOW  1  Are  you 
proficient?  Can  you  send  and  receive 
when  your  country  calls  you? 

THE  "ELECTRO"  CODOPHONE 

(Patents  Pending) 
which  we  present  herewith  is  the 
outcome  of  several  months  of  intense 
study  and  experimentation  of  our 
Mr.  H.  Gernsback.  It  supersedes  our 
former  Radiotone  Codegraph,  which 
comprised  a  Radiotone  silent  Buzzer, 
a  loud  talking  telephone  receiver  and 
a  key.  As  in  all  of  his  work  Mr.  Gernsback  strives  for  simplicity.  So 
he  combined  the  three  above  mentioned  instruments  with  one  stroke  into 
ONE  single  instrument.  He  combined  the  Kadiotone  Buzzer  and  the  loud 
talking  receiver  into  a  single  unit,  not  only  mechanically,  but  electrically 
as  well.  This  involves  an  entirely  new  principle,  never  before  attempted, 
and  on  which  basic  patents  are  now  pending. 

What  this  remarkable  instrument  is  and  does. 
The  "Electro"  Codophone  is  positively  the  only  instrument  made  that 
will  imitate  a  500  cycle  note  exactly  as  heard  in  a  Wireless  receiver,  so 


Pending) 

closely  and  so  wonderfully  clear,  that  Radio  operators  gasp  in  astonish- 
ment when  they  first  hear  it.  And  you  need  no  receivers  over  the  ears  to 
hear  the  imitation  singing  spark,  which  sounds  for  all  the  world  like  a 
high-pitched  distant  powerful  Radio  Station.  No,  the  loud-talking  receiver 
equipped  with  a  horn,  talks  so  loud  that  you  can  hear  the  sound  all  over 
the  room,  even  if  there  is  a  lot  of  other  noise. 

THAT'S  NOT  ALL.  By  lessening  or  tightening  the  receiver  cap,  a  tone 
from  the  lowest,  softest  quality,  up  to  the  loudest  and  highest  screaming 
sound  can  be  had  in  a  few  seconds. 

FURTHERMORE,  this  jack-of-all-trades  marvel,  can  be  changed  in- 
stantly into  our  famous  silent  Radiotone  test  buzzer,  simply  by  replacing 
the  metal  diaphragm  with  a  felt  disc,  which  we  furnish  with  every  instru- 
ment. 

FOR  INTERCOMMUNICATION.  Using  two  dry  cells  for  each  instru- 
ment, two  Codophones  when  connected  with  one  wire  and  return  ground, 
can  be  used  for  intercommunication  between  two  houses  one-half  mile 
apart.  Any  one  station  can  call  the  other,  no  switches,  no  other  appliances 
required.    No  call  bell  either,  the  loud-talking  phone  takes  care  of  this. 

AS  AN  ARMY  TYPE  BUZZER.  Last,  but  not  least,  two  Codophones 
with  two  75  ohm  receivers  can  be  used  to  converse  over  miles  of  fine  (No. 

36  B  &  S  Wire),  so  fine  that  no  one 
_  can  see  the  wire.    Or  you  can  use  a 

Is  ,  -C  long  metallic  fence  and  the  ground, 

fJ^J  or  you  can  communicate  over  your 

  110  volt  line  up  to  several  miles,  us- 

_flL  9   ing  no  wires,  only  the  ground. 

Full  directions  how  to  do  all  this 
furnished  with  each  instrument. 

One  outfit  alone  replaces  the  old- 
fashioned  learner's  telegraph  set, 
consisting  of  key  and  sounder,  which 
is  all  right  to  learn  the  telegraph 
code  but  not  the  wireless  codes. 

The  "Electro"  Codophone  is  a 
handsome,  well  made  instrument, 
fool  proof,  and  built  for  hard  work. 
Contacts  are  of  hard  silver  %  inch 
in  diameter,  that  will  outlast  the  in- 
strument. Base  and  housing  is  of 
metal  throughout,  horn  and  key 
lever  nickel  plated  and  buffed.  Three 
new  style  metal  binding  posts  are 
furnished. 

There  is  also  a  neat  code  chart  and 
full  directions  enabling  any  intelli- 
gent young  man  or  girl  to  learn  the  codes  within  30  days,  practising  one- 
half  hour  a  day. 

Sizes:  6%   x  3  x  2%".     Shipping  weight,  i  lbs. 
The  "Electro"  Codophone  as  described,  complete 

Money  refunded  if  instrument  is  not  as  represented  or  does  not  come  up 
fully  to  expectation. 

Ready  for  delivery  July  25th.  There  will  be  an  enormous  demand  for 
this  new  marvel — place  your  order  now.  All  orders  filled  in  rotation. 
Better  order  two  instruments  today. 


icusmg  one- 

$1.35 


LABORATORY  OUTFIT! 


How  often  have  you  wished  to  possess  a  compact  outfit  in  your 
laboratory  combining  a  Filter-stand  with  a  Test-tube  holder  and 
Spirit  lamp? 


We  have  spent  considerable  time  to 
combine  just  such  a  practical  outfit  and 
present  it  herewith  to  our  friends. 

The  outfit  is  complete  as  per  illustra- 
tion and  consists  of : 

1  Stand,  made  of  well  quartered  oak, 
varnished  three  times,  so  as  to  be  acid 
proof  and  grooved  on  top  and  bottom,  so 
that  it  will  not  warp  in  getting  wet.  Size 
5%  inches  high  by  11%  inches  long. 

1  Glass  Spirit  Lamp.  Size  3%  inches 
by  2  inches.  Uses  wood  alcohol  and  is 
invaluable  to  the  experimenter.  Besides 
being  used  to  heat  test-tubes  contents  as 
per  illustration,  it  can  be  used  to  bend 
glass  rods  and  tubings,  to  solder  wire, 
etc. 

1  Glass  Filter  Funnel.  This  funnel  is 
made  of  heavy  glass  that  will  not  break 
easily.  It  fits  accurately  in  the  hole  on 
top  of  the  Filter  stand  and  is  provided 
with  a  thick  rim  on  the  outlet,  so  that 
a  rubber  hose  can  be  attached  to  it, 
without  slipping  off. 

1  Glass  Rod,  to  be  used  in  stirring  and 
mixing. 

10  Test  Tubes,  made  from  the  best  im- 
ported glass.  A  new  feature  of  some  of 
the  test  tubes  is  that  they  have  a  flat  bottom  and  therefore  can  be  placed  on  any  table  if  desired,  needing  no 
special  stand. 

1  Roll  of  Copper  Clad  Steel  Wire.  This  wire  is  to  be  used  to  make  a  number  of  useful  articles  as  shown  in 
the  illustration,  such  as  test-tube  holders,  tripods  to  support  retorts,  etc.  We  furnish  a  blue  print  with  the 
outfit,  showing  how  to  make  all  these  wire  articles. 

Now  this  whole  outfit  as  described  costs  you  only  

Postage  extra.    Shipping  weight,  4  lbs. 

Order  one  today,  even  if  you  don't  need  it  now. 

We  have  only  500  outfits  on  hand,  and  as  some  of  the  glassware  is  imported,  it  will  be  impossible  to  make  up 
more  during  the  present  war.    First  come,  first  served.    Money  returned  if  sold  out.    Send  for  it  today. 


$1.50 


"Electro"  Pony  Receiver 


Our  Pony  re- 
ceiver is  without 
doubt  the  best  ar- 
ticle for  the  money 
to-day. 

Points  of  superi- 
ority: Hard  rubber 
composition  shell 
beautifully  pol- 
ished. Powerful 
permanent  steel 
magnet,  soft  iron 
core,  fibre  coil 
heads.  very  thin 
diaphragm,  brass 
posts  inside. 
Hanger  can  be  un- 
screwed and  re- 
ceiver will  then  fit 
our  No.  AX807? 
headbands. 

SOME  USES.  — 

For  all  telephone  work.  Also  for  making 
the  small  testing  outfits  for  repair  men  in 
circuit  with  only  one  dry  cell  or  flashlight 
hatterv.  It  can  also  be  us»d  for  wire- 
less though  its  low  resistance  won't  per- 
mit of  such  good  results  as  a  higher 
resistance  phone. 

This  receiver  is  single  pole:  214  x  lVs 
inches;  wgt.  4  oz. ;  resistance,  75  ohms. 

IF  TWO  OF  THESE  RECEIVERS 
ARE  USED,  IT  IS  POSSIBLE  TO 
SPEAK  AT  A  DISTANCE  OF  150 
FEET  WITHOUT  USING  BAT- 
TERIES. ONE  WIRE  BEING  SUF- 
FICIENT IF  GROUND  IS  USED. 
No.  EKI024    Pony  Receiver,  CA— 

75  ohms   OuC 

IMMEDIMATE  SHIPMENTS 


No.  EK  1024 


THE  ELECTRO  IMPORTING  CO. 


Manufacturers 


THE   "ELECTRO"  SPINTHARISCOPE 


As  usual  we  lead — others  follow.  Now  the  Spinthari- 
scope, first  to  be  introduced  to  the  American  public  by 
us.  The  Spinthariscope  was  originated  by  the  famous 
English  Radium  expert,  Sir  William  Crookes.  Everyone 
knows  that  Radium  gives  off  a  tremendous  amount  of 
energy  which  goes  on  for  several  thousand  years,  with 
undiminished  force. 


MAKING  RADIUM. 
VISIBLE 


Radium  gives  off  a  number  of  rays  of  which  the 
Alpha  rays  are  known  chiefly  for  their  great  power. 

These  electric  rays  are  invisible  to  the  naked  eye,  the 
same  as  are  X-rays.  But  if  we  take  a  small  amount  of 
Radium  and  place  it  in  front  of  a  zinc-sulflde  screen, 
the  latter  lights  up.  If  the  radium  speck  is  arranged 
suitably  the  Alpha  rays  will  bombard  the  zinc  sulfide 
with  a  veritable  hail  of  electrons  and  the  screen  begins 
to  scintillate  like  Fourth  of  July  fireworks. 

This  Is  the  principle  of  the  Spinthariscope,  which  we  present  herewith. 
It  is  a  little  instrument  made  of  two  neatly  nickeled  metal  tubes,  one 

You  owe  it  to  yourself  to  own  one.  It  is  small  enough  to  be  put  into 
It  will  continue  to  operate  after  you  are  dead  2500  years!  We  guarante 
Radium  salts.    "Electro"  Spinthariscope,  in  neat  box  and  directions  for  u 

Sent   Prepaid.  IMME 


telescoping  into  the  other.  The  top  tube  has  a  powerful 
lens.  The  bottom  contains  the  zinc-sulflde  screen  and 
a  minute  quantity  of  REAL  RADIUM,  too  small  to  do 
any  harm.  The  instrument  can  only  be  used  in  the 
dark.  After  the  top  tube  with  the  lens  has  been  ad- 
justed to  the  right  focus,  we  observe  a  vividly  illumi- 
nated green  background,  glowing  in  a  soft  light.  As 
the  eye  becomes  accustomed  to  it,  we  begin  to  see  the 
ELECTRONIC  BOMBARDMENT  of  the  Alpha  rays  from 
the  Radium.  It  looks  exactly  like  tiny  fireflies  flashing 
off  and  on  in  the  dark  night.  The  more  we  look  the 
better  we  see  the  miniature  fireworks.  We  are  now  in 
the  presence  of  the  most  marvelous  substance  man  ever 
knew,  RADIUM  and  its  uncanny  forces — Radium,  which 
some  day  will  turn  the  world  upside  down. 

The  Spinthariscope  up  to  now  sold  from  $10.00  up- 
wards, but  by  greatly  simplifying  it  the  cost  has  been  brought  down  by 
us  to  such  a  nominal  figure,  that  no  one  can  afford  to  be  without  this 
most  important  and  marvelous  instrument. 

your  vest-pocket,  and  interesting  enough  to  show  it  to  all  of  your  friends, 
e  the  instrument  to  be  genuine  and  to  contain  a  minute  quantity  of  real 

se,  as  described  <f>-i  An 

DIATE    SHIPMENTS.  .pl.UU 


ll  ; 


BOYS! 

Here  Are  the  Stars 
and  Stripes  in  All 
Their  Glory. 

Be  the  first 
one  in  your 
town  to  wear 
this  patriotic 
emblem.  Think 

0  f  1 1  :  A  n 
electrically  il- 

1  u  m  i  n  a  ted 
b  o  u  tonniere 
worn  in  the 
lapel  hole  of 
your  coat, 
ft  illuminates 

1  our  National 
Flag  in  the 
original  col- 
ors with  a 
brilliant 
electric  light. 
Just  insert 
Flag  in  buttonhole  of  your 
coat,  put  flashlight  case  in 
vest  or  coat  pocket  and  every 
time  you  press  the  button,  the 
flag  in  your  button-hole 
flashes  up  with  a  beautiful 
color  effect. 

Illuminated  flag,  cord  and 
plug  (to  be  connected  to  any 
2  cell  flash-  Ctf\l* 

light)   OUC 

(Postage  10  cents.) 
Illuminated   flag,  flashlight 
case  and   battery,   cord  and 
plug,  complete  as  per  illustra- 
tion, $1.10;  postage  15c. 

DEALERS:  Write   for  our 
proposition  todav. 
IMMEDIATE  SHIPMENTS 


Selenium  Cells 

Everybody  has  read 
about  the  experiments 
of  tele  phot  ogra  pli  y 
(sending  photographs 
over  a  wire  hundreds  of 
miles)  made  by  Profes- 
sor Korn  and  others.  It 
is  also  known  that  if 
the  problem  of  tele- 
vision is  ever  solved,  the  | 
selenium  cell  will  play 
an  important  role.  At 
present  we  are  the  only 
concern  in  the  United 
States  selling  these  cells. 
They  are  the  most  sen- 
sitive ones  made. 

Better  send  for  a  cell 
today  and  try  making  an  electric  dog  that  will 
follow  a  lamp,  or  an  electric  burglar  alarm.  It's 
very  instructive  and  great  fun.  (See  November, 
1916,  issue  "Electrical  Experimenter.")!' 
No.  FX5I7  Selenium  Cell,  each. 
Shipping  Weight,  4  oz. 

IMMEDIATE  SHIPMENTS 


No.  FX5I7 


:$6.oo 


THE  "ELECTRO  TELEGRAPH" 
$J#00 


is  not  a  toy,  but  a  practical,  honestly  built  telegraph  outfit,  which  not  only  sounds 
but  works  like  the  big  commercial  instruments.  By  studying  the  code  for  30  days 
you  can  become  a  first-class  telegraph  operator.  Such  operators  are  in  big  demand 
now.  Outfit  consists  of  TWO  complete  telegraph  instruments  each  measuring  3%  x 
2%  x  2  All  metal  parts  are  highly  nickel  plated,  including  key  lever.  Note  hard 
rubber  knob.  Telegraph  Code  Chart,  telegraph  blanks  and  connecting  wire  conies 
with  set,  but  no  batteries.  Outfit  works  on  2  dry  cells  (one  cell  for  each  instrument). 
The  "Electro"  is  the  ONLY  Outfit  that  works  both  ways,  each  station  can  call ;  no 
switches,  no  extras.  Nothing  to  get  out  of  order.  Guaranteed  to  please  you  or 
money  back.  djl  f\(\ 

Price  Complete  as  illustrated  ipl.VU 

At  all  good  dealers  and  department  stores.  If  your  dealer  cannot  supply  you  send 
us  $1.00  for  outfit  and  add  mailing  charges  for  two  pounds,  otherwise  we  ship 
express  collect. 


The  Livest  Catalog  in  America" 


Our  big,  new  electrical  cyclopedia  No.  18  is  waiting 
you.    Positively  the  most  complete  Wireless  and  el 
trical  catalog  in  print  today.    200  Big  Pages, 
illustrations,   500   instruments   and   apparatus,  et 
Big  "Treatise  on  Wireless  Telenraphy."    20  FREE 
coupons  for  our  100-page  FREE  Wireless  Course 
in  20  lessons.    FREE  Cyclopedia  No.  18  measures 
7x5 M".    Weight  %  lb.    Beautiful  stiff  covers. 

"THE  LIVEST  CATALOG  IN  AMERICA" 

Now  before  you  turn  this  page  write  your 
name  and  address  on  margin  below,  cut  or  ' 
tear  out,  enclose  6  cts.  stamps  to  cover 
mail    charges,    and   the  Cyclopedia 
yours  by  return  mail. 

THE  ELECTRO  IMPORTING  CO. 

231  Fulton  Street,  New  York  City. 


II  FULTON  ST,  NEW  YORK,  N.Y. 


THE  "ELECTRO"  CODOPHONE 


AMATEURS! 
ATTENTION!! 

Now  that  we  are  for  the  time  being,  deprived  of  using  our 
Radio  outfits,  it  behooves  us  as  good  Americans  to  become 
proficient  in  learning  the  Wireless  as  well  as  Telegraph 
Codes.  Operators  who  know  the  Code  are,  and  will  be,  in 
ever  rising  demand.  The  Army  and  Navy  need  thousands 
of  operators  right  now. 

So  far  the  Government  has  not  been  able  to  obtain  any 
way  near  all  the  operators  it  requires.  Not  alone  does  the 
Federal  Government  call  for  thousands  and  thousands  of 
operators  for  the  army  and  navy,  but  nearly  all  of  our  many 


ndln-U 

closely  and  so  wonderfully 
mem  when  tin  y  llr.st  hear  ii 
hear  the  Imitation  slngliij:  sri;i rh. 
high-pitched  dh 
equipped  with  1 


:liat  Radio  operators 

  which  sounds  lor  nil  the  world  II 

;rful  itinUn  Station.    Nil.  the  Imul- t:i tkl rii; 

,  talks  srj  Inud  thill 

 re  Is  a  lot  of  other  noise. 

THAT'S  NOT  ALL.  JSv  lessening  ..r  ttg)ii"'»lrig  the  receiver  cap,  a 
from  the  lowest,  softest  quality,  up  lo  tlie  loudest  and  highest  screi 
sound  en n  I'f  liinf  in  ;i  few  seconds. 

FURTHERMORE.   this  j:ick-of -all-trailes  marvel,   enn  bo  channel 

stantly  Into  our  t.nnoii-  silent  limit"!  ■  test  buzzer,  simply  by  rcpl 

the  metal  diaphragm  with  a  felt  disc,  which  wo  furnish  with  every  ir 

FOR  INTERCOMMUNICATION.  Using  two  dry  cells  for  each  In 
ment,  two  Codoahones  when  connected  with  mie  wire  and  return  gri 
can  be  used  fur  liilercoiimiiinh  .itlou  between  two  houses  one-half 
apart.  Any  one  station  run  •-.til  the  other,  no  switches,  no  other  npplli 
required.    No  call  liell  either,  the  loud-lalklng  phone  lakes  eare  of 

AS  AN  ARMY  TYPE  BUZZER.    Last,  but  not  least, 
with  two  Tj  ohm  receivers  can  bt-  used  to 


inly  the  ground 


B  &  S  Wire),  sc 
can  see  the  wire,  i 
lone  melnlllc  fence 

110  volt  line  ud  to 
ins  no  wires. 

Full  dlreetioi 
furnished  with  each  I 

One  outfit  alone  replaces  the  old- 
fashioned  learner's  telegraph  set, 
consisting  of  key  and  sounder,  which 
Is  all  right  to  learn  the  telegraph 
code  but  not  the  wireless  codes. 
The    "Electro"    Codophone    is  a 

fool  proof,  and  built  for  hard  work.' 
Contacts  are  of  hard  silver  %  inch 
in  diameter,  (hat  will  outlast  (lie  In- 
it.  Base  and  housing  Is  of 
metal  throughout,  horn  and  key 
lever  nickel  plated  and  buffed.  Three 
— *ll   binding   posts  are 

a  neat  code  chart  and 
enabling  any  Intelli- 
learn  the  codes  within  30  days,  practising  i 


;ctro"  Codophone 

refunded  If  n 
expectation. 

for  delivery  July  2f.th, 


2%".  Shipping  weight,  4  lbs. 
described,  complete 

ot  as  represented  or  does 


$1.35 


All  orders  ailed  i 


LABORATORY  OUTFIT! 


tat  i 


complete  as  per  llluslra- 


1  Stand,  made  of  well  quartered  ook, 
varnished  three  times,  so  iis  to  lie  arid 
pr""f  .mil  pronved  un  top  and  bottom.  >" 
lh.it  it  nill  ii,,t  H.irji  in  pelting  wet  Size 

".■>i  In.  In  s  high  Li  11 in,  lies  long. 
1  Glass  Spirit  Lamp.    Size  inches 

by  J  indies.  fsrs  uuml  alcohol  and  is 
lin  .ilii.it. Ic  (u  the  experimenter.  Besides 

per  llliistralioii.  It  cm  be  Umi|  to  l.eicj 
glass  rods  and  tubings,  to  Bolder  wire, 


1  Glass  Filter  F 

de  of  heavy  gb 
illy.    It  tits  acc 
of  the  Filter 
1th  a  thick  rim 

nil. .nt  slipping  o 
1  Glass  Rod,  to 


anel.    This  funnel  is 
that  will  n,.t  break 
rately  In  the  hole  on 
and  and  Is  provided 


■e  used  In  stirring  and 

ade  from  the  best  1m- 
■w  feature  of  some  „r 
If  desired,  needing  im 


lie  all  these  wire  art 
5  described  costs  yo 

Postage  ei 
1  you  don't  need  It  n 
i  on  hand,  and  as  sc. 


1.  Shipping  i 
eat  the  glassv 


$1.50 


"Electro"  Pony  Receiver 


Patents: 

NO.8+Z.S50 

Feb5, 1907 

t0cts;7,l908 
No.9ti^75 
FebU19IO 

No.  951.783 
Mar.6,1910 

No.%1,655 
dune  21. 1910 

No.97<S,999 
Dec  ^0, 1910 

No  986,156 

flpriK.I9|| 

No966,7fef 
April  4.I9H' 

No  1,016,138 
clan  30. 191?. 

No  1033,095 
duly23.l9lgf 

Nolj£)57,8£0 
April  1. 1913 

NolH4l3 
Janlj.1915, 

No  94,9  901 1 
clonic  1914 
i  " 
Patents 
Fending  in' 
fisteni  Office 


8 


THE   "ELECTRO"  SPINTHARISCOPE 


follow.    Now  the  Spinthari 

I  to  tho  American  public  1 
s  originated  by  thc_  famo 


The  Spinthari--.  ..(i, 
llsli  Itadhim  expert.  : 
ws  that  Radium  gives  oh*  a  tremendous 
7  which  goes  on  for  several  thousand 


undiminished  force. 

Radium  gives  on* 
Alpha   rays  are  km 

These  elec 


of  rays  of  which  tb 


Radium  and  place 
the  latter  lights  u 

suitably  Ihe  Alpha  rays  will  bombard 
with  a  verlt.ili!.'  Ii  ill  ..t  electrons  and  the 
to  scintillate  like  I'.. mill  of  .ItHv  firework. 

This  Is  the  principle  ,,r  the  Splnthariicop  . 
It  Is  a  llllle  Instrument  nude  of  tun  neatly  nickeled  metal 
You  owe  It  (o  yourself  lo  own  one.    II  Is  small  enough 
ft  will  continue  to  operate  after  y 
Radium  salts.    "Electro"  Spinthari 


Hut  If  wo  take  ._  _ 
t  In  front  of  a  zlnc-sulndc 

If  the  radium  speck  Is  arranged 


$1.00 


THE  "ELECTRO  TELEGRAPH" 


THE  ELECTRO  IMPORTING  CO.Manutacturers 

mmmmmmmmtmmmm 


Better  send  for  a  ci 
toduv  anil  trv  making 
follow  a  lamp,  or  an  el 
vorv  Instrucllvi 
1U1C,  Issue  "Electrical  Experi 
No.  FX5I7  Selenium  Cell, 
Shipping  Weight,  4  az. 
IMMEDI. 


SHIPMENTS 


231  FULTON  ST.,  NEW  YORK, 

mmmmmmmmm 


258 


THE  ELECTRICAL  EXPERIMENTER 


August,  1917 


Details  of  a  20,000  Meter  Undamped  Radio  Receiver 

By  WM.  BURNETT,  JR. 


A GREAT  deal  has  been  accomplished 
in  the  last  few  years  in  the  recep- 
tion of  undamped  wave  trains.  In 
this  description  I  will  endeavor  to 
relate  some  details  of  the  experi- 
mental work  that  has  been  successfully  car- 


to  the  adjusting  of  the  filament  rheostats. 
In  regard  to  the  resistance  of  the  'phones, 
I  am  convinced  that  the  2,000  ohm  type 
will  work  better  than  the  3,000  ohm  type. 
The  usual  care  should  be  taken  in  connect- 
ing the  filament  of  the  bulb  to  the  negative 


Antenna 


6 rid  cond. 


dud/on  1 


—  6 


Impedance 


4sVo/tbot 

i|lh"l|l 

f/g.l 


Audion  *2 


PnonesQj^ 

2000  6h>Hf~J 

© 


Diagram  of  Circuits  for  20,000  Meter  Undamped   Wave  Audion   Receiving  Set  Which  Has 
Given   Highly  Satisfactory  Results. 


ried  on  at  our  laboratory.  A  great  deal 
of  the  apparatus  ordinarily  involved  in  this 
work  is  rather  expensive,  and  unless  the 
person  has  a  good  knowledge  of  electrical 
laws  he  is  quite  apt  to  get  poor  results. 

The  subject  of  ultra-high  frequency  cur- 
rents has  set  the  amateur  electrical  "bug" 
afire,  and  at  the  present  time  it  is  hard 
to  tell  from  one  day  to  the  next  just  what 
will  turn  up  in  the  way  of  a  new  inven- 
tion. 

In  the  accompanying  diagram  (Fig.  1) 
is  shown  a  very  good  set  of  connections 
for  the  reception  of  long  undamped  waves. 
This  consists  of  very  few  pieces  of  appara- 
tus and  works  admirably  well.  Any  one 
who  has  access  to  two  Audion  (round  or 
tubular)  bulbs  will  find  that  this  is  one  of 
the  most  simple  hook-ups. 

These  connections  give  a  very  sensitive 
circuit  and  by  spending  a  little  time  in 
adjusting  the  Audions  the  experimenter 
will  find  it  possible  to  attain  excellent  re- 
sults. It  is  advisable  not  to  connect  a 
variable  condenser  across  the  'phone  ter- 
minals, as  this  paralyzes  them  to  such  an 
extent  that  the  diaframs  refuse  to  move. 
The  impedance  which  is  connected  in  the 
diagram  is  one  of  about  9,000  ohms ;  a 
spark  coil  secondary,  having  an  iron  wire 
core  running  thru  it,  will  answer  the  pur- 
pose. 

This  hook-up  produces  a  very  strong  re- 
generative effect.  This  can  be  partly  done 
away  with  if  the  proper  attention  is  paid 


binding  post  of  the  lighting  battery  and  the 
rheostat  to  the  positive  post  of  the  lighting 
battery.  However,  all  who  have  had  ex- 
perience with  the  Audion,  know  that  the 


The  loose  coupler  used  in  this  hook-up 
is  one  built  after  the  so-called  Cambridge 
Receiving  Transformer  design.  Its  over- 
all length  is  36  inches  and  the  secondary 
slides  on  a        square  brass  tube.  (Fig.  3.) 

The  primary  is  12"  long  and  8"  in  diam- 
eter, wound  full  of  No.  28  single  silk  cov- 
ered copper  wire,  and  is  divided  into  19 
equal  parts.  Being  of  the  Navy  type,  the 
first  18  taps  are  brought  out  to  switch 
points  and  the  remaining  section  is  divided 
into  19  equal  parts  and  these  brought  out 
to  as  many  switch  points.  The  accompany- 
ing illustration  (Fig.  2)  will  explain  this. 

Rather  than  count  the  turns,  wait  until 
after  winding  and  then  by  direct  measure- 
ment locate  the  position  of  the  taps.  The 
secondary  is  12"  long  and  7"  in  diameter 
and  is  wound  -full  of  No.  33  S.  S.  C.  wife 
and  divided  into  19  equal  sections  and 
brought  out  to  the  switch  points  on  the 
front  of  the  secondary.  As  the  drawing 
below  is  self-explanatory,  giving  the 
principal  dimensions,  no  further  space  will 
be  given  to  the  construction  of  the  receiv- 
ing transformer. 

My  best  results  have  been  obtained  with 
the  following  set  of   connections:  (See 


20,000  meter 
receiving  transformer 
F/g.3 


-ii 

8"- 


T- 


-12' 


Secondary  - 


Wound  *J3  s.s.c  7"d/am. 


 — i 


Primary  wound* 26  \ 
s.s.c.  a" diameter 


 .  1. 


-36" 


is  sec  switch 
points 


Mode  ofj  'red  fiber 

4 


Isg..  brass 
tube 


rb  ■ 

,1 

{*>} 

J 


S/ritches  mpfs.each 


Details  of  20,000  Meter   Loose  Coupler  for   Undamped   Wave  Reception. 


characteristics  of  the  bulbs  differ  and  the 
experimenter  will  be  able  to  adjust  these 
minor  difficulties  by  using  good  judgment. 


■Antenna 

Inductonce  .ooos 
so"  tony 


uctonce  .ooos       ,  Audion  i  a 


Audion  2 


.OOOSM.F 


vlwv-4 


4S/o/t  bat. 


.00!  M.f. 


\$ooo  on  177 
impedance 


Phones 


.001^* 

M.F. 


46 /oil  bat 


— "     Inductance  some  as 
o  -=r       obo/e  so"/$/7f4  d/om.  so  enamel  w/re  ~/g.4 


© 


Detailed  Circuit  Diagram  for  Two-Audion  Continuous  Wave  Radio  Receptor  Operating  On 

the  "Heterodyne"  Principle.  ' 


Fig.  4.)  The  loading  coils  or  inductances 
are  4"  in  diameter  and  32"  long.  These  are 
wound  with  No.  30  enameled  magnet  wire. 
Taps  are  taken  off  at  10  different  places, 
thereby   giving   a   great  variation   of  in- 

USEFUL  HINTS  ON  THE  AUDION. 
By  Frank  J.  Collins. 

IN  this  paper  an  attempt  will  be  made 
to  clear  up  certain  misunderstandings 
current  among  numerous  amateurs  in 
regard  to  the  required  amount  of  apparatus 
employed  in  the  Armstrong  Regenerative 
Audion  receiving  circuits. 

Numerous  articles  have  appeared  in  past 
issues  of  electrical  magazines,  to  the  ef- 
fect that  the  Grid  and  Wing  coils  are  un- 
necessary; that  certain  condensers  could  be 
eliminated;  that  the  body  could  not  ap- 
proach the  apparatus  without  affecting  the 
tuning  considerably  (due  to  the  capacity 
of  the  operator's  body)  and  that  the  oscil- 
lations were  unsteady,  to  say  the  least. 

There  were  furnished  with  these  articles, 
"newly  discovered"  hook-ups  by  the  authors, 
claimed  to  do  the  same  thing  as  the  Arm- 
strong arrangement,  employing  the  minimum 
of  apparatus  and  giving  the  same  results ! 
{Continued  on  opposite  page.) 


August,  1917  THE  ELECTRICAL  EXPERIMENTER 


ductance.  An  advanced  form  of  the  Arm- 
strong regenerative  circuit  is  used  and  is 
here  given  for  Amateur  use  only. 


The  Complete  20,000  Meter  Audion  Receptor 
for    Undamped    Waves,    With    Loading  In- 
ductances and  Large  Loose  Coupler. 

Large  values  of  inductance  and  small 
values  of  capacity  give  the  best  results. 
N.A.A.,  W.L.S.  and  N.AJ.  have  been  heard 
40  feet  from  the  'phones.  Two  pairs  of 
3,000  ohm  'phones  work  very  well  in  place 
of  the  one  pair  of  2,000  ohm.  The  antenna 
from  which  this  set  is  operated  is  100  feet 
high  and  100  feet  long,  of  the  "T"  type. 

USEFUL  HINTS  ON  THE  AUDION. 

(Continued  from  opposite  page) 

In  the  first  place,  the  Grid  inductance 
not  only  acts  as  a  wave  length  tuning  in- 
ductance, but  also  as  a  storage  of  energy. 
This  stored-up  energy  discharges  back  into 
the  Wing  inductance  (which  also  acts  as 
a  storage  of  energy).  The  Wing  induct- 
ance transferring  the  energy  back  again 
into  the  Grid  circuit,  causing  a  greater 
amount  of  current  to  flow,  than  would  or- 
dinarily occur  in  the  absence  of  these  in- 
ductance coils,  and  therefore,  a  greater 
drop  of  current  across  the  telephones  upon 
the  reception  of  signals. 

It  is  impossible  to  obtain  maximum  sig- 
nal strength,  or  to  hold  the  oscillations 
steady,  for  the  reception  of  undamped 
waves,  unless  these  coils  are  employed  and 
adjusted  properly. 

The  complaint  that  the  body  cannot  be 
brought  near  the  apparatus  during  the  re- 
ception of  signals  without  interferring  with 
the  signals,  can  be  overcome  to  a  large 
degree  by  grounding  the  Grid  circuit  be- 
tween the  secondary  of  the  loose-coupler 
and  the  negative  side  of  the  telephone  bat- 
tery, also  by  short-circuiting  the  unused  or 
idle  turns  on  the  Grid  and  Wing  induct- 
ance coils,  and  also  by  grounding  the  head- 
band thru  a  small  condenser. 

These  precautions  will  enable  the  oper- 
ator to  work  the  arrangement  with  little 
or  no  trouble  from  capacity  effects. 

Instead  of  using  long  coils,  30  to  40 
inches  in  length,  four  tubes  of  6-5^-5  and 
414  inches  respectively  in  diameter,  and  8 
inches  long  may  be  wound  full  with  num- 
ber 32  S.S.C.  magnet  wire  and  placed  with- 
in one  another,  using  insulating  rings  to 
separate  the  windings,  taking  care  the  wind- 
ings do  not  oppose  one  another.    This  ar- 


rangement of  coils  will  work  the  same  as 
the  longer  coils  and  take  up  far  less  room. 

The  use  of  extremely  large  loose-coup- 
lers for  long  waves  is  not  necessary.  The 
mutual  inductance  between  primary  and 
secondary  of  such  large  couplers  is  very 
great  and  when  used  in  conjunction  with 
the  Armstrong  circuits  requires  very  long 
(or  loose)  coupling.  An  air  space  of  8 
and  10  inches  between  primary  and  sec- 
ondary is  not  uncommon. 

Practically  the  same  results  will  be  ob- 
tained on  a  much  smaller  coupler,  giving 
smaller  coupling  between  primary  and  sec- 
ondary ;  the  signal  strength  and  tuning 
properties  remaining  the  same  as  for  the 
larger  coupler. 

It  has  been  stated  that  one  should  never 
use  finer  wire  on  the  primary  of  the  loose- 
coupler  and  the  primary  loading  coil  than 
number  24.  That  is  all  right  theoretically 
and  in  the  reception  of  shorter  wave 
lengths,  but  in  dealing  with  undamped  wave 
lengths  the  frequency  is  much  lower,  the 
current  penetrating  further  into  the  wire. 

Number  32  wire  is  found  from  experi- 
ence to  give  practically  the  same  results 
as  number  24  wire,  when  used  as  pri- 
mary loading  inductances  in  receiving 
long  waves,  besides  requiring  a  minimum 
of  space. 

While  it  is  admitted  the  high  frequency 
currents  travel  on  the  surface  of  the  wire 
and  granting  the  surface  of  a  number 
32  wire  is  not  as  great  as  a  number  24 ; 
in  practise,  the  same  signal  strength  will 
be  obtained  and  the  sharpness  of  tuning 
is  not  affected  by  the  finer  wire. 

There  is  no  necessity  of  building  re- 
ceiving transformers  for  the  reception  of 
wave  lengths  in  excess  of  12,000  meters, 
as  there  are  few  stations  at  the  present 
time  using  wave  lengths  above  that  value 
(12,000  meters). 


Close  View  of  20.000   Meter   Loose  Coupler. 
Primary  Control  Switches  at  Right;  Second- 
ary  Coil    at  Left. 

A  variable  condenser  should  not  be 
shunted  across  the  primary  inductances 
for  tuning  in  the  long  wave-lengths,  but  a 
variometer  employed  instead,  as  it  is  well 
known,  a  condenser  so  used,  decreases  the 
current  strength  of  received  signals  con- 
considerably.    (Dr.  Cohen.) 

That  a  short  antenna  is  suitable  for  the 
reception  of  long  wave  undamped  signals 
is  quite  true,  but  all  things  remaining  the 
same,  the  higher  and  longer  the  antenna, 
the  stronger  the  received  signal,  providing 
the  fundamental  wave  length  of  the  an- 
tenna remains  below  that  of  the  received 
wave.  The  above  assertion  holds  true  in 
all  cases. 

Finally,  every  piece  of  apparatus  as  used 
in  1;he  Armstrong  circuits  is  absolutely 
necessary  and  the  elimination  of  any  one 
piece  of  apparatus  decreases  the  efficiency 
of  the  set  proportionally. 

There  is  only  one  fault  to  find  in  con- 
nection with  the  working  of  the  apparatus, 
and  that  is  the  unexperienced  amateur 
who  condemns  it  before  learning  how  to 
work  it. 

There  is  no  doubt  but  what  it  requires 
experience  to  do  real,  serious  long-dis- 
.tance  work,  and  the  trouble  lies  mostly  in 
the  inability  of  the  amateur  and  not  in 
the  apparatus,  if  connected  properly. 


259 

The  apparatus  should  consist  of  a  pri- 
mary loading  inductance  ;  a  loose-coupler — 
Grid  and  Wing  inductance;  Grid  con- 
denser ;  secondary  tuning  condenser  ;  Wing 
coil  condenser,  and  telephone  condenser, 
in  conjunction  with  the  regular  Audion  de- 
tector apparatus. 

In  conclusion,  the  long  tubular  bulb  with 
the  filament  entirely  surounded  by  the  Grid 
and  Wing,  will  give  better  results  for  the 
reception  of  undamped  waves  than  the 
ordinary  round  form,  as  it  is  more  stable 
in  operation. 


HOW  TO  EXTINGUISH  ELECTRIC 
FIRES. 

In  the  extinguishing  of  electrical  fires 
there  is  large  opportunity  for  the  display 
of  good  judgment  and  prompt  action.  The 
element  of  time  is  exceedingly  important. 
The  operator  should  observe  whether  con- 
ditions warrant  the  cutting  of  current  from 
affected  part  before  the  fire  is  attacked. 
His  knowledge  of  the  apparatus  under  his 
charge  should  be  such  as  to  guide  him 
promptly,  says  H.  L.  Ganett  in  E.  D.  &  C. 

Sand  and  powder  bicarbonat  of  soda 
have  been  found  to  have  some  merit  as 
extinguishing  agents  in  certain  kinds  of 
electrical  fires,  but  their  use  is  limited. 

Where  sand  is  provided  for  fire-extin- 
guishing purposes,  it  should  be  carefully 
sifted  thru  a  sieve  of  window  screen  of 
14  mesh  to  remove  the  larger  particles,  es- 
pecially scraps  of  metal.  It  should  be  kept 
in  a  clean  and  dry  condition  and  should 
not  be  used  where  there  is  a  liability  of 
its  getting  into  the  bearings  of  moving 
parts.  . 

In  tests  recently  made  in  extinguishing 
oil  fires,  wet  sawdust  impregnated  with 
sal  ammoniac  has  been  found  to  have  con- 
siderable merit. 

Carbon  tetrachlorid  has  shown  up  well 
as  an  extinguishing  fluid  and  has  the  ad- 
vantage of  being  a  non-conductor  to  a  high 
degree,  which  is  a  very  valuable  attribute. 

In  many  modern  plants  the  liability  of 
structural  fires  is  vastly  less  than  the  lia- 
bility of  the  occurrence  of  fire  in  appa- 
ratus, and  much  of  this  apparatus  is  so 
constructed  that  in  case  of  fire  occurring 
in  the  interior  it  is  very  difficult  or  im- 
possible to  use  an  extinguishing  agent 
with  success 


CONTROL  BY  SOUND. 

At  Lady  Drogheda's  Aircraft  Exhibi- 
tion at  the  Grafton  Galleries,  an  inter- 
esting model  airship  constructed  by  Lieut. 
Roberts,  in  which  the  control  is  effected 
by  sound,  was  recently  exhibited.  Elec- 
tric circuits  are  worked  by  a  telephone 
diafram,  and  this  is  tuned  by  an  air 
column  so  as  to  respond  to  any  desired 
note.     On  sounding  this  note  the  electric 


Co/7  n "  long  a"  d/'om. 


Connection    Scheme    for    Primary    of  20,000 
Meter  Loose  Coupler. 

apparatus  goes  into  action,  the  diafram 
acting  as  a  relay,  and  by  bringing  this  re- 
lay into  action  a  sufficient  number  of  times 
any  particular  motor  can  be  put  into  oper- 
ation. 


260 


THE  ELECTRICAL  EXPERIMENTER 


August,  1917 


Converting  a  Tuning  Coil  into  a  Cabinet  Tuner 

By  N.  H.  ALLEN 


THE  accompanying  idea  is  to  convert  a 
one,  two  or  three  slide  tuning  coil  into 
a  cabinet  tuner  with  rotary  control  at 
small  cost. 

First,  secure  a  suitable  box,  similar  in 
size  to  the  tuner  and  slightly  larger  as 
shown  in  the  drawing,  and  fasten  the  base 


tuner  is  used,  the  top  knob  may  be  marked 
Primary  and  the  bottom  one  Secondary. 
The  whole  of  the  box,  except  scales,  may  be 
varnished  for  good  appearance. 

If  a  chart  be  prepared  as  shown  here,  the 
operator  will  be  able  to  immediately  adjust 
his  tuner  for  listening  in  to  any  desired  sta- 


A'  top  v/eiv 


B"  top  mw 


Srodua/ed  sca/e 


■      '      "\_  J- Pnm 

I    ■\Z\l\4\s\i\l\t\}  \  »V 


Graduated 
"  sca/e 


tVojted  f/shinq 
/me 


iliimpl 


Wood  fox 


"C  front  v/eiv 


© 


Now  Is  a  Good  Time  In  Which  to  Re-design  Your  Radio  Apparatus.     Here's  a  Fine  Idea 
for  Converting  Your  Old  Tuning  Coil  Into  a  "Cabinet"  Style  Set.     By  Changing  Around 
the  Connections  a  Number  of  Effective  Tuning  Arrangements  May  Be  Had. 


of  the  tuning  coil  to  the  back  of  the  box. 
Then  fasten  four  small  screw  hooks  (or 
better  still,  use  small  pulleys)  to  the  box 
in  the  position  shown  in  the  drawing. 
A  small  hole  should  next  be  bored  in  the 
face  of  box  in  order  to  accommodate  the 
rotary  control  knob  shaft,  on  the  inside  end 
of  which  is  fastened  a  small  thread  bob- 
bin. The  drawing  shows  the  manner  of  at- 
taching much  better  than  I  could  describe 
it,  so  I  will  not  go  into  details,  and  anyway 
there  are  no  two  amateurs  that  would  do  it 
just  alike.  When  knob,  bobbin  and  screw 
hooks  are  all  in  position,  a  waxed  piece  of 
fish-line  is  fastened  to  the  slider,  run  thru 
the  hooks  round  the  bobbin  once  or  twice 
and  fastened  securely.  Thus  it  will  be  seen 
that  when  the  knob  on  the  front  of  the 
cabinet  is  rotated  the  slider  will  run  along 
the  coil  to  any  desired  position.  (A  good 
way  to  fasten  the  fish-line  to  slider  is  to 
drop  a  piece  of  melted  wax,  such  as  used 
in  sealing  batteries,  on  the  line  and  slider, 
effectively  holding-  it  in  place  and  which 
does  not  injure  the  slider  in  any  way.) 

Next  refer  to  figure  B,  in  which  the  ap- 
paratus described  above  is  left  out  for  clear- 
ness and  the  next  point  will  now  be  de- 
scribed. This  consists  in  the  pinching  of 
the  minute  hand  from  an  old  clock  or  ma- 
king one  from  tin  or  brass.  Fasten  it  to 
the  slider  in  the  manner  described  above 
for  fastening  the  cord  in  place.  The  end  of 
the  pointer  is  bent  in  the  manner  shown 
so  as  to  project  thru  a  slit  in  the  face  of 
the  box,  cut  the  same  length  as  the  slider 
rod.  (This  is  clearly  shown  in  Fig.  C.) 
Looking  at  C,  it  will  be  seen  that  a  gradu- 
ated scale  is  tacked  or  glued  to  the  front  of 
box  just  above  the  slit.  This  scale  may  be 
graduated  in  any  manner  desired. 

If  a  two  or  three  slide  tuner  is  used,  sim- 
ply duplicate  the  operations  described  here- 
tofore. The  completed  two-slide  tuner  is 
shown  in  C. 

Now  for  the  climax.  When  knobs  are 
moved  the  pointer  will  be  moved  along  the 
graduated  scale  and  show  the  position  of 
the  slider  for  any  operation.    If  a  two  slide 


tion.  Thus  if  (9XE)  is  found  to  come  in 
loudest  when  Prim,  pointer  is  at  7^  and 
when  Sec.  Pointer  at  2>Ya  by  arranging  as 
shown  below,  when  the  operator  wishes  to 
listen  to  (9XE),  he  simply  adjusts  his  tuner 
accordingly;  no  guess  work  being  neces- 
sary. 


Name  of 
Operator 

Operator's 
Address 

Oper's 
Call 
Signal 

Adjust, 
for 
Pri. 

Adjust, 
for 
Sec. 

H.  SMITH 

323  Oswego  St. 
New  Jersey 

GEE 

7.8 

5.1 

J.  GIBSON 

18  St.  Paul  St. 
New  York  City 

WIZ 

9.8 

7.3 

EFFECT  OF  WATER  VAPOR  ON 
THE  PROPAGATION  OF 
ELECTROMAGNETIC 
WAVES. 

An  interesting  paper  on  this  subject  by 
Dr.  Frederick  Schwers,  was  recently  pre- 
sented before  the  Physical  Society  of  Lon- 
don. 

The  author  discusses  the  probable  influ- 
ence of  moisture  in  the  atmosphere  on  the 
refraction  of  electromagnetic  waves  round 
the  earth's  surface.  The  conclusion  of 
Kiebitz  that  the  presence  of  moisture  does 
not  affect  the  dielectric  constant  by  more 
than  10  per  cent,  is  shown  to  be  erroneous, 
being  based  on  the  assumption  that  the 

k—\  l 

Clausius-Mossoti    formula,    -  =con- 

k+2  d 

stant,  holds  when  passing  from  the  liquid 
to  the  gaseous  state.  Examples  are  quoted 
to  show  that  this  law  fails  in  many  cases, 
especially  where  the  dielectric  constant  is 
high  in  the  liquid  state. 

In  the  absence  of  more  accurate  data 
for  ordinary  temperatures,  the  author  pre- 
fers to  assume  a  value  for  the  dielectric 
constant  of  water  vapor  obtained  by  ex- 
trapolating the  results  obtained  by  Baed- 
eker for  higher  temperatures.  The  extra- 
polated value  is  almost  certainly  too  low. 

From  this  result,  and  the  average  con- 


ditions of  the  atmosphere  over  the  ocean 
with  regard  to  temperature  gradient,  etc., 
deduced  from  meteorological  data,  it  is 
shown  that  the  lowest  layers  of  the  atmos- 
phere (1,000  to  1,500  meters  approximately 
in  depth)  refract  electromagnetic  waves  to- 
wards the  earth,  so  that  the  greater  part 
of  the  space  waves  will  reach  the  receiver, 
contrary  to  the  conclusion  of  Kiebitz. 

Dr.  C.  Chree  in  discussion,  says: — The 
author,  presumably  unaware  of  their  exr 
istence,  does  not  refer  to  the  somewhat 
numerous  upper  air  data  which  have  been 
publisht  in  this  country  (England)  by  the 
Meteorological  Office.  A  study  of  this  data 
as  to  the  temperature  gradients  would,  I 
think,  have  proved  useful.  Inversions  are 
not  confined  to  the  lowest  layers,  but  in 
these  layers  they  are  exceptional,  and  do 
not  suffice  to  reduce  the  average  temper- 
ature gradient  to  such  low  values  as  the 
author  has  taken  for  the  first  and  second 
kilometers.  For  these,  5  deg.  or  6  deg. 
per  kilometer  would  not  have  been  too 
high,  especially  for  tropical  regions.  If 
the  empirical  exponential  formula  for  va- 
por pressure  be  assumed,  the  pressure  at 
any  given  height  varies  directly  with  that 
at  ground  level,  and  so  in  temperate  lati- 
tudes is  much  lower  in  winter  than  in  sum- 
mer. It  thus  seems  rather  a  fundamental 
point  whether  wireless  phenomena  in  tem- 
perate latitudes  show  a  marked  annual 
variation  corresponding  with  that  of  vapor 
pressure  at  ground  level. 


A  DUPLEX  POLARITY  POTEN- 
TIOMETER. 

By  the  diagram  given  it  will  be  noticed 
that  two  batteries  are  employed  instead  of 
the  one  battery  formerly  employed  with 
the  potentiometer ;  this  by  no  means  changes 
the  ordinary  hook-up,  and  while  serving  for 
the  same  purpose  as  usual,  eliminates  the 
continual  shifting  of  battery  or  detector 
leads  when  inserting  either  one,  in  order 
to  find  the  correct  connection.  I  have 
found  that  this  connection  works  very  good, 
especially  when  experimenting  as  most  ama- 
teurs do ;  i.e.,  continually  changing  detectors 
and  circuits.  When  the  slider  is  at  the  mid- 
dle of  the  potentiometer  the  instrument  is 
cut  out  of  the  circuit  and  a  change  either 
from  positive  to  negative  is  made  possible 
by  moving  the  slider  either  above  or  below 
the  point  marked  O,  thereby  making  it  un- 
necessary to  shift  detector  or  battery  leads 
in  order  to  get  the  correct  polarity.  Your 


By    Means    of    the    Duplex  Potentiometer 
Scheme  Shown,   It  Is  Possible  to  Quickly 
Reverse  the  Battery  Current  Thru  the  De- 
tector or  Other  Device. 

old  potentiometer  is  easily  converted  for 
this  circuit  by  taking  off  a  lead  from  the 
center  of  the  grafite  rod  or  coil. 
Contributed  by        EDW.  T.  JONES. 


i 


August,  1917 


THE  ELECTRICAL  EXPERIMENTER 


W  C2N5TRUQTER 


B 


*4  •■  "%  ATS"  in  this  case  is  short  for 
batteries.    All  those  who  expect- 
ed a  nature-fake  story,  or  a  trea- 
tise on  the  kind  of  bats  which 
unkind  people  say  inhabit  the  bel- 
fries of  electrical  experimenters,  may  now 
pass  out  quietly  thru  the  door  on  the  ex- 
treme left.    And  please  don't  slam  it ! 


"One  of  My  First  Attempts  In  Battery  Re- 
search," Relates  the  Author,  "Took  the  Form 
of  a  Modified  Gravity  Cell  in  which  I  Tried 
to  Control  the  Action  of  the  Copper  Sulfate 
By  Means  of  a  Small  Hole  In  Its  Glass 
Retainer  'S.'  " 

The  old  house  where  I  lived  and  moved 
and  had  my  shop  hadn't  been  wired  for 
electricity  when  it  was  built.  You  see,  at 
that  time  builders  were  quite  conservative 
about  including  electric  fixtures  in  the 
specifications,  because  the  only  lighting  cur- 
rent in  existence  was  being  produced  in 
laboratories  at  a  cost  of  about  a  hundred 
dollars  per  kilowatt-hour.  In  fact,  elec- 
tricity was  in  its  infancy;  and  if  you  know 
anything  about  infancy  you'll  recognize  that 
its  expense-bill  was  running  true  to  form. 

By  the  time  I  began  to  take  notice,  elec- 
tric lighting  had  conquered  the  streets  and 
had  begun  to  invade  the  houses.  It  was 
useful  mostly  as  one  of  those  modest  means 
of  advertising  that  you  were  "well  off," 
same  as  the  cast-iron  hound  on  the  front 
lawn.  If  you  succeeded  in  blowing  your- 
self like  this  without  the  grocer  getting 
uneasy  about  his  overdue  bill,  the  inference 
was  that  you  and  Want  were  strangers, 
and  that  the  mortgage  had  been  left  on  the 
domicile  simply  in  a  public-spirited  effort 
to  keep  money  m  circulation.  As  mere 
illumination  the  light  was  negligible,  burn- 
ing at  various  low  degrees  of  candle-power, 
and  usually  going  out  whenever  the  neigh- 
bors dropt  in  to  admire  it. 

I  speak  thus  bitterly  of  the  early  light 
because  it  was  an  unsatisfied  hankering  of 
mine  to  have  this  current  on  tap  for  the 
operation  of  the  various  electrical  machines 
which  my  young  factory  turned  out  with 
regularity.  The  Fates  said  me  nix  on  that, 
and  I  defied  them  as  one  must;  but  it  peeves 


"Bats" 

By  THOMAS  REED 

me  that  now  in  my  flat,  when  I  can  have  all 
the  "juice"  I  feel  like  paying  for — I  haven't 
any  shop!  Fates  are  like  that:  if  they 
conclude  to  hand  you  the  thing  you've 
wished  for,  they  wrap  up  with  it  a  neat 
kibosh  to  prevent  any  enjoyment  of  it.  It's 
just  when  the  fish  are  biting  fit  to  take  your 
leg  off,  that  your  bait  gives  out,  now 
isn't  it? 

However,  you  know  we  old  fellows  are 
great  for  finding  reasons  why  any  given 
calamity  was  "all  for  the  best,"  and  I  can 
console  myself  for  the  lack  of  the  piped 
lightning  in  this  way:  if  I'd  had  the  handy 
electric  socket  and  one  of  those  dinky  toy 
transformers  they  sell  in  these  days  (which 
consume  me  with  envy  just  as  a  great  big 
shut-eye  doll  with  real  hair  consumes  a  girl 
of  any  age  from  9  to  90)  I  should  have 
mist  the  pleasure  of  experimenting  with 
batteries. 

The  question  of  operating  current  was 
always  with  me,  butting  in  like  the  tradi- 
tional hag  among  the  good  fairies  at  the 
christening  of  every  new  rinktum,  with  the 
threat  of  stunting  its  career  thru  malnutri- 
tion.   To  provide  my  scientific  family  with 


When  the  Valve  Action  Shown  In  Fig.  1,  Did 
Not  Seem  Very  Promising,  the  Author  Tried 
Out  a  "Siphon"  for  Controlling  the  Flow  of 
the  Copper  Sulfate  Solution,  which  Is  a  New 
One  On  Us. 

their  daily  ration  of  wattage  was  a  grim, 
endless  duty;  so,  more  from  necessity  than 
inclination,  I  was  continually  fussing  with 
batteries. 

The  first  battery  I  ever  saw  was  the  one 
used  to  actuate  the  family  medical  coil. 
It  was  a  zinc  cylinder  suspended  in  a  cop- 
per can,  using  a  "straight"  blue-vitriol  solu- 
tion as  an  electrolyte.  In  action,  it  bubbled 
and  boiled,  and  produced  whiskers  on  the 
zinc  and  mud  on  the  bottom  with  surpris- 
ing industry.  It  would  run  the  coil  for 
about  half  an  hour,  after  which  you  had 
to  clean  it,  and  after  that,  clean  yourself  : 
so  take  it  all  together  the  coil  gave  you  a 
lot  of  exercise  as  well  as  faradic  effects. 
Father  used  it  mostly  to  relieve  his  insom- 
nia; after  the  thing  was  all  packed  away 


again,  and  he'd  had  his  bath,  he  could  usu- 
ally sleep  quite  well.    Electricity  is  life! 

That  mud-battery  was  the  one  I  used  on 
my  first  sounder,  the  one  with  the  gate- 
hinge  for  an  armature.  It  was  quite  strong 
while  going  at  its  proper  stride,  though  not 
much  stronger  than  the  gate-hinge  de- 
manded. But  when  father's  reserve  stock 
of  blue  vit.  solution  was  all  used  up,  and 
I  had  duly  received  my  "talking;-to"  for 
diverting  it  from  its  beneficent  mission  of 
nerve-relief,  I  saw  distinctly  that  it  was 
too  rich  for  my  blood.  It  was  related  to 
my  own  finances  in  about  the  ratio  that 
three  chorus-girls  and  a  spendthrift  son 
would  bear  to  an  elderly  bookkeeper. 

The  flower  of  Bughood  would  have 
frozen  in  the  bud  but  for  good  Pere 
Leclanche.  You  remember  Leclanche's  or- 
iginal wet  cell — nothing  could  have  fitted 
better  the  wants  and  the  pocketbook  of  the 
struggling  Bug.  I  wish  all  the  wattage 
that  the  old  wet  cells  ever  produced  could 
be  collected  and  burned  in  a  neon  lamp  as 
big  as  a  barrel  in  honor  of  that  benefactor 
of  the  race  of  boys ! 

You  could  make  a  Leclanche  cell  for  as 
near  nothing  as  figures  will  come  without 
lying.  Any  old  cut-off  bottle  would  do  for 
a  jar.  For  the  porous  cup  we  used  a  can- 
vas bag.  For  a  nickel  the  junkman  would 
part  with  a  large  piece  of  second-hand  sheet 
zinc ;  sal  ammoniac  and  black  oxid  of 
manganese  were  the  only  cheap  goods  in 
the  drugstore.  For  the  carbon  we  made  a 
raid  on  the  gas  works,  where  the  rounded 
scales  from  the  retorts  were  thrown  out 
in  heaps,  there  being  no  use  for  them  in 
those  days.  Gee,  but  that  carbon  was  hard ! 
It  was  impossible  to  saw  or  work  it  in  any 
way.  To  secure  plates,  we  would  shatter 
up  a  big  hunk  and  select  from  the  result- 
ing hunklets  such  as  happened  to  occur 
somewhere  near  the  desired  size. 

A  battery  made  in  this  way,  with  the 
jagged  end  of  the  carbon  protruding  from 
(Continued  on  page  282) 


Bur/op  folded 
over  edge  of  ^ 
inner  jar 


Inner  gloss 
/or mtfy  copper 
sulfote  solution 


Sulfate  copper 
crystal* 


© 


Finally  the  Gravity  Cell  Research  Work 
Boiled  Down  to  the  Type  Shown.  The  Copper 
Sulfate  Oozed  Out  By  Capillarity  Thru 
Several  Layers  of  Burlap  Dipping  In  Both 
Solutions. 


262 


THE  ELECTRICAL  EXPERIMENTER 


August,  1917 


An  Ingenious  Battery  Night  Lamp 


I  describe  herewith  what  I  call  a  night 
light.  It  is  fastened  to  the  wall  near  the 
bed  and  when  I  wish  to  know  the  time  I 


tery  terminals  make  contact  with  brass  or 
copper  strips,  Ai  and  Bi.  The  reason  for  this 
is  so  battery  is  easier  to  change  in  re- 


Lower  f 
contort  2 


Hook  for  iY<7/c/?f3 

fJas/7//g/)f  £h//^/T  ' 
M/mafure  Base  B 


© 


detected.  The  idea  in  soldering  it  is  to 
get  underneath  this  oxid  while  the  surface 
is  covered  with  molten  solder. 

First : — Clean  all  dirt  and  grease  off  the 
surface  of  the  metal  with  a  little  benzine 
[bearing  in  mind  that  benzine  forms  an 
explosive  mixture  when  in  contact  with  air, 
and  for  that  reason  should  not  be  kept  near 
any  flame  whatsoever]. 

Second : — Apply  the  solder  with_  a  copper 
bit,  and  when  the  molten  solder  is  cover- 
ing the  surface  of  the  metal,  scratch  thru 
the  solder  with  a  small  wire  scratch  brush. 
By  this  means  you  break  up  the  oxid  on 
the  surface  of  the  metal,  underneath  the 
soldering,  and  the  solder,  containing  its  own 
flux,  takes  up  the  oxid  and  enables  you,  so 
to  speak,  to  tin  the  surface  of  the  aluminum. 
Contributed  by  ALBERT  W.  WILSDON. 


Do  You  Keep  Your  Watch  Beside  the  Bed  At  Night?  Here's  a  Nifty  Battery  and  Lamp 
Attachment  Which  Enables  One  to  Light  the  Dial  by  Simply  Pulling  on  the  Fob  or  Chain. 


just  give  a  slight  pull  on  the  watch  fob 
and  can  tell  the  time  by  the  light  of  the 
miniature  bulb.     In  the  drawing  the  bat- 


newing  than  it  would  be  if  wires  were 
soldered  direct  to  them. 

Contributed  by  J.  A.  SIMONIS. 


AN  ELECTRICAL  MUSICAL  TOP. 

Here  is  a  plan  for  making  an  electric  top 
which  will  play  a  tune.  It  consists  of  a 
top  run  by  an  electric  motor.  On  the  in- 
side of  the  top  are  placed  small  tubes,  each 
fitted  with  a  reed  of  different  tone.  On 
the  end  of  each  tube  is  a  circuit-breaker 
which  is  opened  by  an  electro-magnet.  One 
terminal  from  each  electro-magnet  is  con- 
nected to  the  rod  running  thru  the  top, 
the  other  terminal  being  connected  to  a 
small  brass  disc,  insulated  from  the  rod. 
Each  magnet  has  a  separate  disc  and  a 
small  brass  spring  brush.  Each  spring  is 
permanently  connected  with  a  key  on  a 
keyboard.  The  discs  must  be  separated 
slightly  from  each  other.  In  operation,  the 
motor  is  started,  a  key  is  prest  on  the 
keyboard,  the  current  passes  thru  elec- 
tro-magnet, causing  the  hole  in  the  end  of 
the  tube  to  open.  This  permits  the  air  to 
pass  thru,  thus  causing  a  suction  which 
vibrates  the  reed.  By  having  enough  reeds 
to  form  the  musical  scale  a  tune  can  thus 
be  played.  Since  the  electro-magnets  are 
connected  in  multiple,  more  than  one  note 
can  be  produced  at  a  time. 

Contributed  by       EARL  FINFRO'CK. 


MINIATURE  ELECTRIC  LIGHTS 
FROM  110  VOLT  LAMP. 

To  do  the  following  "stunt"  will  re- 
quire quite  some  patience,  so  don't  get  dis- 
couraged if  it  does  not  pan  out  well  at 
first.  Procure  a  few  burned-out  110-volt 
Mazda  lamps,  say  from  10  to  15  watts,  and 
shake  or  jar  a  bulb  until  all  the  wires  are 
broken  loose  from  the  supports  or  the 
frame  to  which  the  fine  wires  are  attached. 
Now  turn  the  bulb  so  that  the  heavy  end 
is  pointing  down  and  get  all  the  broken 
pieces  of  wire  on  the  side  of  the  bulb 
where  the  current  enters.  Quickly  invert 
the  bulb  and  some  of  the  wires  may  fall 
across  the  lead  in  wires — -or  they  may  not. 
If  they  do  not,  try  it  over  again.  When 
you  get  a  wire  or  two  to  hang,  connect 
a  small  current  to  the  lamp  and  you  will 
have  a  light,  and  a  cheap  one  too.  I  gen- 
erally connect  a  flashlight  battery  at  first, 
in  order  to  weld  the  small  wires  firmly  in 
place,  and  then  by  means  of  a  transformer 
and  rheostat,  adjust  the  current  until  the 
lamp  burns  at  full  brightness.  I  have  ob- 
tained as  much  as  32  C.  P.  from  nine 
volts  on  such  a  lamp. 

Contributed  by       EARL  MELDRIM. 


HOW  TO  SOLDER  ALUMINUM. 

In  soldering  aluminum,  it  is  necessary  to 
bear  in  mind  that  upon  exposure  to  the  air 
a  slight  film  of  oxid  forms  over  the  sur- 
face of  aluminum,  and  afterwards  pro- 
tects the  metal.  The  oxid  is  the  same  color 
as  the  metal,  so  that  it  cannot  easily  be 


To  baft. 


This  Electric  Spun  and  Variable  Tune  Top   Will   Interest  Young  and  Old 
Alike.    A  Set  of  Keys  Control  Electric  Circuits  Actuating  the  Various  Tone 
Reeds  Within  the  Revolving  Top. 


August,  1917 


THE  ELECTRICAL  EXPERIMENTER 


263 


An  Electrolytic  Interrupter  for  Low  Voltages 


THE  main  advantages  of  the  electro- 
lytic interrupter  are :  Increased 
number  of  interruptions  per  second, 
increased  spark  length  and  intensity 
and  remarkable  steadiness  of  the 
image  when  used  for  X-ray  work.  The 
electrolytic  interrupter  also  makes  a  con- 


© 


Sectional  View  of  Low  Potential  Electrolytic 
Interrupter  for  Use  on  Voltages  as  Low  as 
12,  and  Provided  with  an  Adjustable  Anode, 
Thermometer  and  Special  Means  for  Keeping 
the  Solution  Hot. 


denser  for  the  primary  of  the  coil  unnec- 
essary: The  only  draw-back  is  the  neces- 
sity of  using  a  voltage  of  about  110  volts 
when  employing  the  usual  type  of 
"Wehnelt"  interrupter. 

In  the  following  it  will  be  shown  how 
the  interrupter  may  be  modified  to  work 
at  a  potential  of  only  12  volts,  thus  enabling 
the  experimenter  who  has  only  a  storage 
battery  or  primary  batteries  at  his  dis- 
posal, to  work  his  coil  with  an  electrolytic 
interrupter.  The  interrupter  consists  of 
an  inner  stoneware  jar  B,  and  an  outer 
one  A.  Both  are  separated  by  a  layer 
of  cotton-wool  C.  The  inner  jar  carries 
a  wooden  cover  E,  which  fits  air-tight  into 
B.  This  is  achieved  by  using  a  small 
rubber  band  S,  in  a  groove  in  the  cover, 
the  groove  having  such  a  depth  that  the 
outer  diameter  of  the  rubber  ring  in  posi- 
tion is  about  1/32  inch  larger  than  the 
inside  diameter  of  the  jar.  A  very  slight 
pressure  will  be  sufficient  to  fix  the  cover 
E  into  the  jar.  From  the  cover  E  is 
suspended  a  lead  plate  G,  bent  as  shown. 
This  plate  is  held  in  position  by  the  screw 
Q,  of  the  binding  post  K.  A  glass  tube 
F,  Y%"  diameter  is  fitted  into  the  cover 
E  and  has  a  small  hole  at  the  lower  end 
to  let  the  platinum  wire  O  pass  thru. 
This  wire  is  attached  to  a  lead  rod  N, 
which  in  turn  is  fixt  to  an  adjusting  screw 
M.  This  screw  works  in  a  small  hard- 
rubber  plate  L,  which  is  attached  to  E, 
by  three  wood-screws  R.  H  is  a  ther- 
mometer, reading  up  to  120  degrees  or 
150  degrees  centigrade ;  it  passes  thru  a 
hole  in  cover  E.  I,  is  a  small  glass  tube 
bent  as  shown  and  mounted  in  the  cover 
E  in  such  a  manner  that  the  lower  end 
just  projects  thru  E. 

The  reader  may  be  puzzled  why  two 
containers  are  used  where  one  would  be 
sufficient,  but  the  reason  is  that  for  such 


By  C.  A.  OLDROYD 

low  voltages  as  mentioned  above,  i.  e.,  12 
volts,  the  diluted  acid  in  the  interrupter 
must  be  kept  at  a  temperature  of  about 
90  degrees  centigrade  to  ensure  proper 
working.  The  layer  of  cotton-wool  C, 
keeps  the  heat  in  the  inner  vessel  B,  and 
once  the  diluted  acid  in  B  is  warmed,  it 
will  remain  warm  for  several  hours.  The 
gases  produced  by  the  interrupter  can  only 
escape  thru  the  glass  tube  I,  as  the  cover 
E  fits  airtight  in  B.  As  the  small  sketch 
shows,  the  tube  I  is  connected  by  means 
of  rubber  tubing  to  a  second  glass  tube 
Y,  fitting  into  a  stopper  Z,  both  being  fixt 
into  a  glass  bottle  containing  a  solution 
of  water  and  washing  soda,  which  neu- 
tralizes the  gases  produced  by  the  inter- 
rupter when  working.  The  tube  Y  reaches 
abqut  2"  below  the  level  of  the  solution 
and  the  stopper  Z,  has  a  notch  on  one 
side  to  let  the  gases  escape,  after  they 
have  past  thru  the  soda  solution,  and  thus 
been  neutralized.  To  warm  the  solution 
in  the  inner  container  B,  of  the  interrupter, 
it  is  only  necessary  to  withdraw  the  jar 
B  by  gripping  it  at  the  projecting  part 
and  place  it  on  a  radiator  or  on  a  gas 
ring  until  the  thermometer  shows  '  about 
90  degrees  centigrade.  Then  the  container 
B  can  easily  be  replaced  into  A,  in  the 
same  way.  When  warming  the  solution, 
care  should  be  taken  to  do  this  gradually 
or  the  jar  may  crack. 

To  build  this  interrupter  let  us  first  pro- 
cure two  stone  jars,  A  and  B,  which  should 
be  approximately  of  the  dimensions  given. 
Place  some  cotton-wool  on  the  bottom  of 
the  outer  vessel  A  and  compress  it  slightly 
by  placing  B  into  A.  The  thickness  of 
the  wad  of  cotton-wool  should  be  about 
Yi" .  Now  fill  the  remaining  space  between 
A  and  B  with  cotton-wool,  always  com- 
pressing it  with  your  fingers.  Next  cut 
a  small  ring  D,  from  wood  about  J4" 
thick,  and  glue  it  into  A.  This  ring  serves 
to  keep  the  cotton-wool  in  position  when 
withdrawing  or  replacing  the  inner  jar  B. 
Next  turn  the  cover  E  from  hard  wood 
y  thick,  making  the  lower  part  fit  easily 
into  B.  Cut  the  groove  shown  and  place 
a  rubber  band  S  into  it.  As  mentioned 
above  the  outer  diameter  of  S  when  in 
position,  should  be  about  1/32"  larger  than 
the  inner  diameter  of  the  jar  B.  Drill  a 
hole  Y%"  diameter  thru  the  center  of  the 
cover  for  the  glass  tube  F  and  three  other 
holes  T,  U  and  V,  as  shown  in  detail 
drawing  of  the  cover.  T  is  for  the  ther- 
mometer, U  for  the  glass  tube  I,  and  V 
is  a  clearance  hole  for  the  screw  Q,  of 
the  binding  post  K.  This  cover  plate  must 
now  be  soaked  in  molten  paraffin  wax  for 
at  least  half  an  hour. 

We  turn  now  to  the  glass  tube  F.  This 
is  Ay%'  long  by  y%"  diameter.  Take  a  tube 
about  15"  long  and  heat  the  middle  over 
a  Bunsen  burner  until  the  glass  becomes 
fairly  soft.  Then  draw  the  two  ends  apart 
and  you  will  have  two  glass  tubes  with 
tapering  ends.  Cut  the  taper  where  the 
bore  is  about  and  smooth  it  on  sand- 
paper. Now  cut  off  the  parallel  part  of 
the  tube  to  make  the  total  length  4y&" 
and  fit  the  tube  into  "E,  by  means  of 
shellac  varnish.  We  now  come  to  the  ad- 
justing screw:  Procure  a  screw  M,  with 
3/16"  thread,  by  about  one  inch  long ; 
solder  to  M  a  piece  of  lead  rod 
N  2>y%'  long  by  %"  diameter  and  solder 
to  N  a  platinum  wire  O.  This  should 
be  one  millimeter  diameter  by  y%"  long. 
If  you  have  a  slightly  smaller  or  larger 
gage    in   your    possession,    yon    may  use 


it,  as  the  diameter  of  the  wire  is  of  no 
great  importance.  The  hard  rubber  plate 
L,  is  next  made  to  the  dimensions  given 
in  the  detail  drawing,  and  the  center  hole 
is  tapt  to  suit  the  adjusting  screw  M.  The 
plate  L  is  then  painted  with  shellac  varnish 
at  the  side,  which  is  to  be  in  contact  with 
the  cover  and  screwed  to  E  by  means  of 
three  small  screws  R.  The  next  part  to 
be  completed  is  the  lead  plate  G.  This 
is  made  from  strip  about  1^4"  wide  by 
18  gage  thick,  and  bent  as  shown.  G  is 
then  fixt  in  position  by  screwing  Q,  into 
the  binding  post  K.  The  thermometer  H 
and  glass  tube  I,  are  now  put  in  place, 
using  again  shellace  varnish. 

The  interrupter  is  now  complete  and 
has  to  be  filled  with  a  solution  of  one  part 
of  sulfuric  acid  in  ten  parts  of  water,  and 
stir  the  water  all  the  time  with  a  glass 
rod.  (Pour  acid  into  water — never  water 
into  acid.) 

The  wash  bottle  is  next  made  from  an 
eight-ounce  glass  bottle  or  any  similar  size. 
The  glass  tube  Y  is  of  the  same  diameter 
as  I,  and  bent  as  shown.  The  stopper  L 
receives  a  notch  as  mentioned  before. 
Place  some  lumps  of  washing  soda  into 
the  bottle  and  pour  sufficient  water  on  it 
to  bring  the  water  level  about  2"  above 
the  end  of  tube  Y.  Finally  connect  I  and 
Y  by  means  of  rubber  tubing. 

The  interrupter  is  connected  in  series 
with  the  primary  of  the  coil,  the  lead  plate 
being  the  cathode.  (A  lead  sleeve  covering 
a  copper  wire  may  be  used  instead  of  a 
lead  rod  for  the  anode.) 


HOW   TO    MAKE  FIREPROOF 
PAPER. 

Dip  a  sheet  of  paper  in  a  strong  solu- 
tion of  alum  water,  and,  after  drying  it, 
repeat  the  process  three  (3)  times;  then 
hold  it  in  a  flame  and  it  will  not  burn. 

To  melt  steel  as  easily  as  lead,  heat  a 


four  holes  fdw  - 


@  /o/errupter 


Wosf?  i>o/l/e 


Details   of   Low   Voltage    Electrolytic  Inter- 
rupter and  Arrangement  of  Wash  Bottle  for 
Neutralizing  the  Gas  Fumes  Produced. 


piece  of  steel  in  a  fire  until  it  is  red,  then 
take  it  out  and  touch  it  with  a  piece  of 
brimstone  (sulfur).  As  soon  as  the  brim- 
stone touches  the  steel  the  metal  will  melt 
and  drop  down  like  liquid. 

Contributed  by        JAMES  MILLEN. 


264 


THE  ELECTRICAL  EXPERIMENTER 


August,  1917 


A  Hand-Feed  Arc  for  the  Experimenter 


I  give  herewith  a  sketch  of  an  arc  lamp 
of  my  own  design.  The  right  hand  bind- 
ing post  is  connected  to  the  stationary 
carbon.  The  left  hand  binding  post  is 
connected  to  the  hinge  F,  and  is  fastened 
along  the  wood  standard  R.  By  turning 
the  threaded  rod  A,  this  causes  the  slider 
C,    which    is  not 


for  110  volt  circuits  some  resistance  is 
absolutely  necessary.  For  110  volt  D.C. 
service  the  value  of  resistance  approxi- 
mates 11  to  12  ohms.  It  may  be  in  the  form 
of  a  water  rheostat. 

Contributed  by        JAMES  PRATT. 


Chain  or  . 
wire  cobje 


Bo/ 

Height  -  - 


threaded,  to  lower 
or  raise  the  brass 
arm  I.    (Fig.  1.) 

It  is  best  to  make 
all  of  the  parts 
such  as  the  base  and 
upright  R,  of  slate, 
fiber,  soapstone, 
marble  or  other 
non  -  combustible 
material.  They  may 
be  constructed  of 
sheet  iron  with  a 
little  care  as  to  the 
insulation,  using 
mica  washers  and 
bushings  on  the 
screws.  The  car- 
bons may  be  small 
or  large,  the  stand- 
ard size  for  com- 
mercial arcs  being 
Yz  inch  diameter. 
A  spiral  spring  G, 
formed  of  phosphor 
bronze  or  steel 
wire,  pulls  the  bar 
I  downward.  The 
glass  lamp  chimney 
is  retained  in  place 
by  a  wood  or  fiber 
ring.  This  arc  lamp 
is  well  adapted  for  use  in  small  motion  pic- 
ture machines,  post  card  projectors,  model 
search-lights,  wireless  telephones,  speak- 
ing arcs,  etc. 

Fig.  2,  (left)  shows  a  balanced,  straight- 
line-feed  arc  lamp  which  the  amateur 
electrician  will  find  easy  to  construct. 
Iron  pipe  can  be  used  with  standard 
flanges,  etc.,  to  make  it  with.  The  toothed 
rack  is  riveted  to  a  piece  of  iron  or  steel 
rod  A,  the  rack  sliding  in  a  slot  in  the 
front  face  of  guide  bar  B.  A  pinion  is 
mounted  in  this  slot  to  mesh  with  the 
rack,  the  pinion  being  rigidly  secured  to 
the  arc  adjusting  handle  and  shaft.  The 
balance  weight  should  just  about  balance 
the  moving  carbon  holder.  Fig.  2,  (right) 
illustrates  the  rack  and  pinion  action  in 
standard  handfed  arc  lamps. 

Regarding  the  current  to  be  used  with 
it,  this  may  be  either  A.C.  or  D.C.  The 
arc  will  give  a  powerful  light  on  50  to  60 
volts  and  5  to  8  amperes.  It  works  best 
with  a  ballast  resistance  in  series ;  this  may 


Grooved  pulleys 


W/re 


dross 


F/ter 


Fig.  2. —  Hand-Feed  Types  of  Arc  Lamp  Which  Lend  Themselves  R 
tional  Skill  of  the  Amateur  Electrician 


TO  KEEP  HUMAN  PESTS  AWAY 
FROM  YOUR  AUTO. 

How  many  of  you  fellows  who  own  an 
automobile  are,  to  put  it  mildly,  peeved, 
to  have  some  person  leave  their  hand- 
marks  on  its  glossy  finish,  or  if  it  hap- 
pens to  be  covered  with  a  light  film  of 
dust,  leave  their  delicately  inscribed  mono- 
gram traced  therein.  Some  of  this  of  course 
is  thru  carelessness  and  some  thru  the  ir- 
resistible impulse  of  some  people  to  see 
their  name  or  trade-mark  in  every  pos- 
sible place.  The  result  however  is  the 
same,  leaving  the  car  in  a  messy  looking 
condition,  and  oftentimes  actually  injur- 
ing the  finish. 

My  car,  however,  has  of  late  been 
strangely  immune  from  this  slight  source 
of  annoyance  apparently  due  to  a  "short" 
in  the  electrical  connections.  Whenever  I 
am  in  the  car  and  some  "nut"  starts  ex- 
hibiting his  skill  in  engraving  on  the  metal 
body  of  the  bus  this  short  develops, 
and  believe  me,  he  suddenly  loses  all  in- 
terest in  his  art,  and  rather  shows  a  tend- 
ency to  do  a  little  vaudeville  turn,  exe- 
cuting something  similar  to  the  "High- 
land Fling." 

The  secret,  however,  lies  in  the  fact  that 
I  have  a  small  spark-coil  connected  to  my 
storage  battery  and  in  turn  connected  to 
the  metal  body  of  the  car,  with  a  push 
button  located  in  a  place  not  readily  seen, 
but  at  the  same  time  easily  got  at,  with- 
out attracting  attention.  I  will  not  attempt 
to  describe  connections  of  this  stunt,  as 
anyone  can  easily  hook  it  up.  But  take  it 
from  me  it  gives  Results,  with  a  capital 
"R". 

Contributed  by  H.  H.  L. 


carboy  into  pitchers  or  jars  by  means  of 
which  the  individual  battery  cells  are  filled 
is  a  difficult  task  and  results  in  consider- 
able trouble,  loss  and  contamination  of 
solution,  wasting  of  time,  and  frequently 
destruction  of  clothing.    Where  there  are 
quite  a  number  of  stationary  battery  cells 
to  be  filled,  as  in  the  case  of  a  new  installa- 
tion or  where  the  electrolyte  is  being  com- 
pletely renewed," 
says      George  A. 
Broder,  in  E.  R.  & 
W.  £.,  "I  find  that 
a  carboy  pump  sim- 
ilar to  the  one  illus- 
trated is  a  desirable 
adjunct. 

"This  device  con- 
sists of  a  foot  pump 
or  bellows  con- 
nected by  a  rubber 
tube  to  a  rubber 
stopper  in  the  neck 
of  the  carboy  ;  from 
this  stopper  another 
tube  leads  to  the 
jars  or  cells  to  be 
filled.  The  rubber 
stopper  must  fit 
very  tightly,  has 
two  holes  passing 
thru  it  and  into  one 
of  these  is  placed 
a  short  piece  of 
glass  or  hard-rub- 
ber tube  to  the  top 
of  which  the  tube 
from  the  pump  is 
connected.  Thru  the 

other    hole    in  the 
eadily  to  the  Construc- 

stopper  passes  a 
long  piece  of  glass 
or  hard-rubber  tubing  which  is  pre- 
ferably curved  slightly  so  as  to  reach  the 
lowermost  part  of  the  carboy;  this  glass 
tube  projects  above  the  rubber  stopper  just 
enough  to  permit  fastening  the  discharge 
tube  or  hose  to  it. 

"The  principle  of  the  device  is  very  sim- 
ple. Air  is  forced  in  from  the  pump  or 
bellows  and  creates  a  pressure  on  the  sur- 
face of  the  electrolyte  or  acid  in  the  car- 
boy. This  forces  the  electrolyte  up  thru 
the  glass  tube  and  discharge  hose  which 
can  be  carried  to  any  jar  or  cell  to  be 
filled.  The  tubing  should  be  of  one-fourth 
or  three-eighths  inch  internal  diameter. 
By  this  device,  especially  if  a  bellows  is 
used,  a  steady  pressure  can  be  maintained 
upon  the  electrolyte  so  as  to  secure  a  con- 
stant flow  regardless  of  the  amount  of 
liquid  left  in  the  carboy ;  in  fact  the  car- 
boy can  be  emptied  to  almost  the  last  drop. 
By  placing  a  small  pinchcock  near  the  end 
of  the   filling  or  discharge  hose,   or  by 


P/n/on 
attached  fo 
regulating 
handle 


F//?er  co ye  red 
r/refs 


Rubber  stopper 


Ri/bbertube 


loot  pump  Crote 


Corbou 


Fig.   1. — A   Swinging   Carbon   Type   of  Arc 
Lamp  for  Amateurs. 

consist  of  a  few  short  coils  of  iron  or 
German  silver  wire  about  No.  20  gage. 
The  resistance  should  be  adjustable  and 
1 


HOW  TO  PUMP  BATTERY  ELEC- 
TROLYTE FROM  CARBOYS. 

"Electrolyte  for  storage  batteries  is  usually 
shipt  in  carboys  which  are  heavy  and  un- 
wieldy. The  ordinary  method  of  pouring 
the  electrolyte  or  acid  directly  out  of  the 


Method  Whereby  Battery  Electrolyte  Can  Be 
Pumped  by  Comprest  Air  from  Carboys  Into 
Cells. 


bending  this  hose  sharply,  it  is  possible 
to  stop  the  flow  of  electrolyte  without  spill- 
ing a  drop  when  changing  from  one  cell 
to  another." 


August,  1917 


THE  ELECTRICAL  EXPERIMENTER 


265 


AN  ELECTRIC  PLAYER  FOR 
TUBAPHONES. 

By  J.  W.  F.  BOWLES 

DOOR-BELL  music  would  hardly  ap- 
peal to  city  people  any  more  than 
grass-hopper  music  to  a  farmer,  but 
an  apparatus,  consisting  of  Drummers' 
Bells  and  ordinary  electric  house  bells  with 
the  gongs  removed,  will  produce  music 
which  is  virtually  door-bell  music  and 
which  is  finding  favor  with  musicians  pa- 
tient and  handy  enough  to  construct  the 
simple  attachments. 

As  seen  in  the  diagram,  the  working 
parts  of  ordinary  vibrating  bells  are  fas- 
tened to  a  frame,  which  sets  over  the 
rows  of  tubes.  The  bells  as  well  as  the 
frame  itself  are  adjustable,  making  it  pos- 
sible to  adjust  the  hammer  of  each  bell  to 
strike  its  corresponding  tube  squarely. 


Even  the  Musician  Finds  Electricity  Useful. 
Here  We  Have  the  Details  for  Making  an 
Electric  Player  for  Tubaphones. 

Several  keys  may  be  struck  at  once. 
Any  pianist  or  a  drummer  who  plays  bells 
can  operate  the  key-board  for  which,  how- 
ever, a  lingering  touch  is  preferable  to 
that  of  the  pianists'  staccato. 

The  instrument  may  be  introduced  into 
an  orchestra  as  a  novelty  but  in  dance 
halls  it  may  be  used  permanently  with 
great  success. 

Description  of  Apparatus  (See  Illustration) 

(A)  Tubaphones  in  case. 

(B)  Frame  with  sharps  and  flats. 

(C)  Frame  with  naturals.  To  play  the 
tubes  the  frames  (B)  and  (C)  are  set 
over  the  tubes  in  case  (A)  so  the  hammer 
of  bells  strike  the  center  of  tubes. 

(D)  Supports   for  holding  backboards. 

(E)  Felt  under  resting  part  of  supports. 


HINTS    ON    WEIGHING  CHEMI- 
CALS. 

Many  of  the  chemicals  used  for  making 
up  battery  and  other  solutions  used  by 
electrical  experimenters  can  be  weighed 
quite  well  upon  a  small  piece  of  tissue 
paper,  this  being  used  to  keep  the  scale 
pans  clean.  Another  piece  of  paper  of  the 
same  size  should  be  placed  in  the  other 
pan  to  avoid  errors  in  weighing.  Some 
such  dodge  as  this  is  particularly  useful 
when  a  cheap  balance  is  used,  having  the 
pans  suspended  by  means  of  thin  cords 
past  thru  holes  in  their  edges.  These  cords 
retain  small  particles  of  the  substances 
weighed  and  so  give  rise  to  impurities  in 
solutions  subsequently  prepared. 

A  better  plan  than  the  above  is  to  use 
a  couple  of  watch  or  clock  glasses,  two 
being  required  so  that  one  does  not  have 
to  wait  while  the  glass  is  washed  after  a 
previous  weighing.  With  the  tung  of  a 
file  scratch  a  circle  on  the  back  of  one  glass, 
and  a  cross  on  the  other.  Then  make  two 
counterpoises  from  thin  sheet  metal,  mak- 
ing one  round  and  the  other  like  a  Maltese 
cross,  to  avoid  all  possibility  of  mistaking 
which  is  which. 

Contributed  by  H.  J.  GRAY. 

Same  on  balance  of  (E)  supports. 

(F)  Backboard  containing  the  bells. 

(G)  Adjusting  screws  for  adjusting  bell 
to  strike  tubes  to  various  pitches. 

(H)  Leverboard  or  keyboard  on  which 
are  mounted  the  keys  to  make  circuit  to 
bells.  The  keys  are  arranged  in  an  order 
corresponding  to  the  tubes  in  order. 

(I)  Five  one  and  a  half  volt  dry  cells. 
Wet  batteries  can  be  employed  in  the  same 
manner  and  circuit.  If  open  circuit  bat- 
teries are  employed  and  a  greater  quan- 
tity of  current  is  required  (which  is  neces- 
sary when  the  bells  are  in  continual  serv- 
ice) the  batteries  should  be  placed  in  mul- 
tiple-series, which  means  a  repetition  of 
the  present  set  connected,  positive  to  posi- 
tive and  negative  to  negative.  As  well  as 
the  former,  alterating  or  direct  current 
from  power  lines  can  be  attached  to  the 
outfit  as  described  under  (L)  and  (M). 

(J)  Positive  binding  post  and  bell  bat- 
tery wire. 

(K)  Negative  binding  post  and  key  bat- 
tery wire.  (J)  and  (K)  can  be  reversed, 
as  there  is  no  set  positive  and  negative 
connections  to  the  operating  apparatus. 

(L)  Step-down  transformer  apparatus 
reducing  the  voltage  from  110  volts  to  8 
volts  on  alternating  current  circuits.  An 
attachment  plug  is  connected  with  a  length 
of  No.  16  flexible  wire,  with  reinforced 
insulation,  and  is  then  attached  to  the  pri- 
mary side  of  the  transformer.  The  sec- 
ondary side  of  transformer  has  wires  pro- 
vided to  connect  to  (J)  and  (K)  binding 
posts — eliminating  battery  wires. 

(M)  A  direct  current  power  line  cir- 
cuit with  resistance  to  reduce  the  voltage 
from  110  volts  to  8  volts.  Connections  can 
be  employed  in  the  same  manner  as  de- 
scribed under  (J)  and  (K). 

(N)  Attachment  plugs  that  will  fit  any 
Edison  socket  or  receptacle. 

(O)  Shows  how  individual  bell  is 
mounted  to  backboard  (F).  The  band 
iron  brackets  are  fastened  to  the  back- 
board by  means  of  stove-bolts.  The  bell 
is  also  secured  to  the  bracket  in  the  same 
manner  with  a  piece  of  felt  between  the 
two,  to  eliminate  any  foreign  sound  while 
the  bells  are  in  action.  The  bells  in  this 
equipment  have  two  ohms  resistance  and 
must  all  be  of  the  same  make  and  adjust- 
ment. The  wire  is  No.  18  for  sections 
and  No.  16  for  battery  or  main  lines  which 
are  lettered  (J)  and  (K).  The  wires  in 
the  present  equipment  are  individual,  have 
rubber  insulation  and  are  cabled.  A  stand- 
ard cable  can  be  employed  if  the  distance 
between  parts  is  great. 


AN  INTERESTING  RADIOGRAPHIC 
EXPERIMENT. 

The  following  experiment,  which  I 
worked  up  several  years  ago,  has  always 
proved  of  interest  to  men  somewhat  ad- 


Radio-Actlvity  Is  an  Absorbing  Study;  Here 
We  Have  a  Photo  Made  by  Exposing  a 
Covered  Plate  to  the  Rays  of  Uranyl-Chlorld. 


vanced  in  scientific  experimentation. 

An  experiment  of  interest  to  those  who 
find  pleasure  in  Radiography  is  that  per- 
formed by  Niewenglowski  several  years 
ago.  The  material  furnishing  the  radia- 
tions is,  in  this  case,  calcium  sulfid,  such  as 
is  used  in  the  manufacture  of  phosphores- 
cent paint.  A  photographic  plate  is  placed 
in  a  plate-holder  A,  and  instead  of  a  cover- 
slide,  a  thin  sheet  of  aluminum,  B,  is  in- 
serted. Upon  the  aluminum  are  placed 
squares  of  thin  glass,  and  on  these  pieces 
of  calcium  sulfid,  D,  previously  exposed  for 
some  time  to  sunlight.  These  are  protected 
by  a  cover  glass,  E. 

The  apparatus  is  left  in  the  dark  for 
twenty-four  hours  or  so  and  the  plate  then 
developed.  The  particles  radiating  from 
the  sulfid  will  have  penetrated  the  aluminum 
and  affected  the  sensitized  photograph  plate. 

The  phenomenon  is  similar  to  that  ob- 
served about  the  same  time  as  Niewenglow- 
ski by  Becquerel,  in  respect  to  the  salts  of 
Uranium.  It  was  later  found,  however,  that 
the  uranium  salts  exhibit  this  property  of 
affecting  a  plate  without  previous  exposure 
to  light. 

From  the  similarity  to  the  action  of  the 
recognized  radioactive  elements,  and  from 
the  accepted  theory  of  radioactivity,  an  ex- 
planation for  this  phenomenon  can  be  de- 
rived. The  calcium  atom  in  the  salt  ex- 
plodes, or  decomposes,  as  does  Radium  and 
the  other  radioelements,  giving  rise  to  a  yet 
unknown  substance  (perhaps  a  calcium  em- 
anation), and  the  characteristic  penetrating 
rays ;  from  their  nature,  the  B-rays.  It  is 
these  B-rays  which  penetrate  the  aluminum 
and  affect  the  plate.  That  the  calcium  salt 
must  be  exposed  to  light  in  order  to  secure 
this  radioactivity  is  probably  due  to  the  ra- 
dio-weakness of  calcium. 

(If  the  experimenter  is  able  to  secure  any 
of  the  uranium  salts,  either  from  a  repu- 
table chemical  house  or  from  the  ore,  re- 
sults will  be  much  more  easily  attained  and 


A  -  Plate  holder 

B  ■Jlum/num  sfteef  ^  

C ■  6/oss  p/ofe  i 
O-Su/p/i/te             (5    J  ™\ 

t- Cover   W$u  |  \  -^kz 

— -  © 

How    the    Apparatus    Is  Ar- 
ranged in  Performing  the  Ra- 
diographic    Experiment  Here 
Described. 

will  be  more  satisfactory.  The  accompa- 
nying photo  print  was  made  from  uranyl- 
chlorid.) 

Contributed  by  J.  S.  MARCUS. 

(University  of  Colorado.) 


266 


THE  ELECTRICAL  EXPERIMENTER 


r\/7 


mm  w 


August,  1917 


This  department  will  award  the  following  monthly  prizes:    First  Prize,  $3.00;  Second  Prize,  $2.00;  Third  Prize,  $1.00. 

The  purpose  of  this  department  is  to  stimulate  experimenters  towards  accomplishing  new  things  with  old  apparatus  or  old  material, 
and  for  the  most  useful,  practical  and  original  idea  submitted  to  the  Editors  of  this  department,  a  monthly  series  of  prizes  will  be  awarded. 
For  the  best  idea  submitted  a  prize  of  $3.00  is  awarded;  for  the  second  best  idea  a  $2.00  prize,  and  for  the  third  best  prize  of  $1.00.  The  article 
need  not  be  very  elaborate,  and  rough  sketches  are  sufficient.  We  will  make  the  mechanical  drawings.  Use  only  one  side  of  sheet.  Make 
sketches  on  separate  sheets. 


FIRST  PRIZE,  $3.00 
A  NOVEL  ACOUSTIC  AMPLIFIER. 

An  amplifier  which  nearly  equals  an 
Audion  in  its  sensitiveness  and  which  re- 
quires no  battery  current  to  operate  it  is 
described  herewith. 

It  is  however  better  suited  for  use  in  re- 
generative vacuum  detector  receiving  sets, 
that  use  a  capacity  to  vary  the  number  of 
beats. 

Referring  to  the  illustration,  R  is  the 
telephone  receiver  (of  1,000  or  1,500  ohms 
resistance),  while  H  is  a  Helmholtz  reso- 
nator. The  resonator  is  mounted  so  that 
the  large  opening  fits  over  the  hole  in  the 
ear  cap  of  the  receiver. 

The  number  of  beats  is  then  regulated 
(by  turning  the  variable  condenser)  until  a 
clear  response  is  heard.  As  a  resonator  of 
this  type  responds  only  to  a  certain  note, 
the  beats  must  be  regulated  until  the  reso- 


The   Simplest   Amplifier  for   Radio    Is  That 
Shown.  Which  Involves  the  Use  of  a  Helm- 
holtz Resonator. 


nator  is 

The  sy 
what  les 
less  set, 
by  first 
the  inco 
resonato 
Contri 


in  resonance  with  the  receiver, 
stem  may  also  be  used  (with  some- 
s  efficiency)  on  an  ordinary  wire- 
i.e.,  one  using  a  crystal  rectifier, 
carefully  ascertaining  the  pitch  of 
ming  signal  and  then  choosing  a 
r  of  the  proper  pitch, 
buted  by  F.  G.  THACKABERRY. 


LOCATING  ARMATURE  GROUNDS 
WITH  A  TELEPHONE  RECEIVER. 

A  simple  method  for  locating  a  grounded 
coil  in  an  armature,  will  appeal  to  all  electri- 
cians having  to  care  for  motors  or  gen- 
erators. This  test  can  be  made  without 
removing  the  armature. 

Remove  all  the  brushes  from  the  com- 
mutator with  the  exception  of  two  located 
diametrically  opposite.  These  brushes  are 
connected  to  a  few  cells  of  dry  battery 
and  a  buzzer,  as  shown  in  the  illustra- 
tion. 

A  telephone  receiver  has  one  terminal 
connected  to  the  frame  of  the  machine, 
while  the  other  terminal  is  connected  to  a 


SECOND  PRIZE,  $2.00 

COMBINED     PENCIL  RHEOSTAT 
AND  LAMP  SOCKET. 

Here  is  an  improvement  on  my  vest- 
pocket  rheostat  described  in  the  October, 
1916,   issue   of   The   Electrical  Experi- 


With   a   Pencil,  a  Clip  and  a    Lamp  Socket 
Shell    One    May    Construct    a  Vest-pocket 
Rheostat  and    Lamp  Socket. 

menter,  and  as  now  constructed,  it  will  be 
found  very  handy  for  testing  the  strength 
of  small  lamps. 

In  addition  to  slotting  the  pencil  and 
making  the  other  details,  secure  a  socket 
from  a  porcelain  base,  such  as  are  used  for 
miniature  lamps,  and  force  this  over  the 
end  of  the  pencil.  If  necessary,  an  ad- 
hesive may  be  employed.  Make  the  wire 
connections  as  shown,  so  that  the  current 
will  travel  via  the  inserted  lamp  after  pass- 
ing thru  the  grafite  resistance,  as  regulated 
by  the  fountain  pen  clip. 

Contributed  by     JOHN  T.  DWYER 

third  brush,  which  bears  on  the  commu- 
tator midway  between  the  other  two. 

On  starting  the  buzzer  a  sound  will  be 
heard  in  the  'phone.  The  armature  should 
then  be  turned  slowly,  keeping  the  brushes 
in  the  same  relation  to  each  other,  until 
no  sound  is  heard  in  the  telephone ;  this 
will  indicate  that  the  bar  connected  to  the 
grounded  coil  is  under  the  middle  brush. 

Due  to  the  winding  in  wave-wound 
armatures  it  will  be  found  that  there  are 
as  many  ''silent"  or  nearly  silent  bars  as 
there  are  poles  in  the  machine.  The  proper 
one  can  be  found  by  selecting  the  one  which 
gives  the  least  sound  in  the  receiver. 
Should  more  than  one  be  entirely  "sil- 
ent" increase  the  number  of  batteries  in 
series  with  the  buzzer  until  it  is  found  that 
one  bar  gives  less  noise  than  the  others 
in  the  series. 

Contributed  by   THOS.  W.  BENSON. 


Tel  rec 


3*  brush 


HHHh 


© 


-Baft 


THIRD  PRIZE,  $1.00 
A  SIMPLE  WHEATSTONE  BRIDGE. 

Select  a  piece  of  board  of  dimensions 
8"  x  15"  x  1"  thick.  This  should  be  well- 
seasoned  wood,  preferably  some  non-resin- 
ous kind.  Bore  holes  for  the  binding- 
posts  and  the  mercury  cups,  as  shown  in 
the  drawing. 

The  contact  keys  are  made  of  strips  of 
hard  sheet  brass,  bent  as  shown. 

For  the  ratio  coils  No.  22  B.  &  S.  double- 
cotton  covered,  German  silver  wire  will 
be  found  the  most  convenient.  It  is  very 
desirable  to  adjust  these  coils  to  exactly 
one  and  ten  ohms  each  respectively,  but 
this  is  not  essential.  Good  results  can  be 
obtained  by  simply  measuring  off  lengths 
of  one  and  ten  feet  very  accurately.  The 
resistance  of  these  wires  will  not  vary 
greatly  from  the  values  marked,  and  their 
ratio  will  be  very'  close  to  10  :  1,  which  is 
the  essential  thing. 


The    Amateur    Electrician    Will    Find  This 
Small  Wheatstone  Bridge  Useful  As  Well  As 
Instructive. 

All  permanent  connections  shown  in  the 
sketch  should  be  very  carefully  soldered 
on  the  under  side  of  the  bridge.  A  coat 
or  two  of  orange  shellac  will  make  a  neat 
appearance. 

This  apparatus,  used  in  connection  with 
an  ordinary  resistance  box  (.1  to  110 
ohms),  will  give  a  possible  range  for 
measurements  from  .01  to  1100  ohms. 

This  bridge  will  commend  itself  on  ac- 
count of  its  teaching  value,  since  it  fol- 
lows the  theoretical  Wheatstone  bridge  de- 
sign very  closely.  Another  good  feature 
is  its  low  cost.  The  necessary  materials 
need  not  cost  over  seventy-five  cents,  and 
the  labor  involved  in  its  construction  is 
very  small. 

Contributed  by 

PETER  J.  M.  CLUTE. 


Method  of  Testing  for  "Grounds"  on  Motor 
and  Dynamo  Armatures  with  a  Buzzer,  Bat- 
tery and  Telephone  Receiver. 


Due  to  the  advent  of  the  war,  we  are 
particularly  desirous  of  obtaining  manu- 
scripts describing  original  and  practical 
"Electrical  Experiments."  We  shall 
continue  to  publish  Radio  articles,  but 
what  we  need  is  snappy  "Electrical" 
articles.  Be  on  guard  for  the  enemy — 
Repetition! 


August,  1917 


THE  ELECTRICAL  EXPERIMENTER 


267 


Experimental  Chemistry 


NITRIC  ACID.  (HISTORY). 

(HNOs) 

NITRIC  ACID  was  probably  known 
to  the  ancient  Egyptians  and 
alchemists  as  Aqua  Fortis  (Strong 
Water).  Geber  is  credited  with 
having  prepared  it  in  the  Ninth 
Century  by  strongly  heating  a  mixture  of 


Glass    Retorts   With   and    Without  Stopper. 
They  Are  Used  Extensively  in  Chemical  Re- 
searches. 

Saltpeter  (Potassium  Nitrat),  Alum,  and 
Copper  Sulfate,  the  Nitric  Acid  distilling 
over,  owing  to  the  decomposition  of  the 
Saltpeter  by  the  Sulfuric  Acid  of  the  other 
salts.  Nitric  Acid  was  commonly  pre- 
pared and  used  as  a  valuable  reagent  by 
the  alchemists,  especially  as  a  means  of 
separating  Gold  from  Silver. 

(.Synonyms  —  Aqua  Fortis, 
Strong  Water,  Azotic  Acid, 
Hydrogen  Nitrat,  Hydric  Ni- 
trat, Spirit  of  Niter.) 

Glauber  about  1650  prepared 
it  by  a  similar  method  to  the 
one  which  is  now  used,  name- 
ly, by  the  action  of  Oil  of 
Vitriol  (Sulfuric  Acid)  on 
Niter   (Potassium  Nitrat). 

Lavoisier  first  determined 
the  composition  of  this  acid 
about  1776.  He  proved  that 
one  constituent  was  Oxygen, 
but  was  unable  to  prove  the 
nature  of  the  others. 

Cavendish  proved  the  exact 
composition  and  mode  of  for- 
mation of  this  acid  of  its  salts 
by  the  direct  combination  of 
Oxygen  gases  in  the  presence 
of  water  or  alkaline  solutions. 

Priestley,  from  his  experi- 
ments, observed  that  when  a 
series  of  electric  sparks  was 
made  to  pass  thru  air  included 
between  short  columns  of  a 
solution  of  litmus,  the  solution 
acquired  a  red  color  and  the  air  was  dimin- 
ished in  volume. 

In  the  place  of  litmus,  Cavendish  per- 
formed similar  experiments  to  Priestley's, 


By  ALBERT  W.  WILSDON 

Fifteenth  Lesson 

using  what  was  known  as  Soap-lees  (Caus- 
tic Potash)  and  Lime-water.  He  con- 
cluded that  the  Soap-lees  (Caustic  Pot- 
ash) and  the  Lime-water  became  satu- 
rated with  some  acid  during  the  operation. 
He  proved  that  this  was  Nitric  Acid,  by 
passing  the  electric  discharge  thru  a  mix- 
ture of  pure  Dephlogisticated  Air  ( Oxy- 
gen) and  pure  Phlogisticated  Air  (Nitro- 
gen) .over  Soap-lees  (Caustic  Potash), 
when  Niter  (Potassium  Nitrat)  was 
formed. 

In  1816,  Gay-Lussac  found  the  ratio  of 
Hydrogen,  Oxygen,  Nitrogen,  correspond- 
ed with  H,0,  NaO,. 

Occurrence : 

Like  Hydrochloric  Acid,  Nitric  Acid 
does  not  occur  in  the  free  state  in  Nature, 
its  affinities  being  too  strong.  After  thun- 
der-storms, or  electrical  discharges  in  the 
air,  traces  are  found.  It  occurs  in  large 
quantities  combined  in  the  form  of  Alka- 
line Nitrats,  the  two  important  ones  being 
Sodium  Nitrat  [NaNOs],  found  in  large 
quantities  in  Chile,  and  also  being  known 
as  Chile  Saltpeter ;  and  Potassium  Nitrat 
[KNOs]  which  is  found  in  India,  also 
known  as  Niter,  Saltpeter,  and  Bengal 
Saltpeter. 


trated  Sulfuric  Acid  and  Sodium  Nitrat 
be    heated    to    about    130°,    Nitric  Acid 


Test  tube 

Bottle  filled  I 
With  water 


Retort 


'Iron  gauze 


~  Fig  77  — 


Sunsen 
Burner 


NaNOa 
Sodium 
Nitrat 


Optional  Method  of  Mounting  Retort  on  Iron 
Tripod   for   Performing    Experiment   No.  82. 

[HN03],  is  volatilized.  The  reaction  is 
represented 

f  H2S04  =  NaHS04  +  HNO3 
Sulfuric  Sodium  Nitric 
Acid  Hydrogen  Acid 

Sulfate 

The  two  salts,  Sodium  Ni- 
trat [NaNOs]  and  Sodium 
Hydrogen  Sulfate  [NaHSOi] 
are  not  volatile.  The  Nitric 
Acid  boils  at  86°,  the  Sulfuric 
Acid  boils  at  330°.  It  is  thus 
obvious,  when  heated  at  100', 
the  Nitric  Acid  is  volatilized 
and  the  state  of  equilibrium  of 
the  solution  disturbed,  thus  the 
Sodium  Nitrat  is  all  decom- 
posed. 

If  the  temperature  be  high- 
er, Normal  Sodium  Sulfate 
[Na2S04]  is  formed,  requiring 
the  use  of  less  Sulfuric  Acid. 

In  comparison  of  the  two 
equations : 


Bunsen/ 
dower 


Ring/  force/am  'mortar 
stand    and  pestle 


Seo/rer  c.'c  cruel  He  Glass 
Graduate  pone/a/n 


Florence 
f/asA 


NaNOs 
Sodium 
Nitrat 


H,S04 
Sulfuric 
Acid 


Typical  Ou 
of  Importa 


Ring  jfancf^ 


Retorts 


Test  tube 
1 

l 

dott/e  filled  I 

>r,?,'e. '  I 


rig.  76 


Method  of  Setting  Up  Retort,  Bunsen  Bur- 
ner, Condenser,  Etc.,  in  Experiment  No.  82. 


tfit  for  An  Experimental  Chemist's  Laboratory.  Hundreds 
nt  Experiments  Can   Be  Performed  with  This  Equipment. 

The  formation  of  the  nitrats  are  sup- 
posed to  have  their  origin  in  the  putrefac- 
tion of  nitrogeneous  or  organic  matters, 
the  latter  are  assumed  to  be  converted  into 
Ammonia  [NH.,],  and  this  to  be  oxidized 
in  the  presence  of  the  hydrat  of  potassium 
[K],  Sodium  [Na],  or  Calcium  [Ca],  into 
the  corresponding  nitrat. 


Preparation  : 

The  acid  is  prepared  both  commercially 
and  in  the  laboratory  by  the  action  of  Sul- 
furic Acid  on  some  Nitrat. 

Either  Potassium  or  Sodium  Nitrat  may 
be  employed,  but  owing  to  the  greater 
abundance  and  less  expensive  cost  of  So- 
dium Nitrat,  this  is  generally  used. 

When  Sodium  or  Potassium  Nitrat  is 
mixed  with  dilut  Sulfuric  Acid,  no  ob- 
trusive sign  of  chemical  action  takes  place, 
altho  it  can  be  proved  that  a  reversible 
change  has  taken  place,  so  that  the  Sodium 
is  distributed  between  the  Sulfuric  and 
Nitric  Acids.     If   a  mixture  of  concen- 


=    HNaS04  + 
Sodium  Hvdrogen 
Sulfate 


HN03 
Nitric 
Acid 


and  also 

2NaNOs  +  H2S04  =  Na2S04   +  2HN03 

Sodium       Sulfuric       Sodium  Nitric 

Nitrat             Acid          Sulfate  Acid 

we  can  see  that  these  reactions  are  similar 
to  those  obtained  when  we  prepared  Hy- 
drochloric Acid  [see  July,  1917,  issue  of 
the    Electrical    Experimenter],  insofar 


Method  of  Pouring  Sodium   Nitrat  Into  Re- 
tort   from    a    Creased    Paper.  Experiment 
No.  82. 

that  an  excess  of  acid  is  employed,  as  in 
the  first  reaction,  a  moderate  heat  is  re- 
(Contiiiued  on  page  274) 


268 


THE  ELECTRICAL  EXPERIMENTER 


August,  1917 


Under  this  heading  we  publish  every  month 
useful  information  in  Mechanics,  Electricity 
and  Chemistry.  We  shall  be  pleased,  of 
course,  to  have  our  readers  send  us  any 
recipes,  formulas,  wrinkles,  new  ideas,  etc., 
useful  to  the  experimenter,  which  will  be 
duly  paid  for,  upon  publication,  if  acceptable. 


USEFUL  CHEMICAL  HINTS  FOR 
AMATEURS. 

In  many  chemical  experiments  a  ring- 
stand  is  needed,  but  as  these  are  some- 
what expensive  a  substitute  will  be  wel- 
come. The  stand  is  made  of  two  rings  of 
heavy  iron  or  copper  wire,  one  larger  than 
the  other,  with  three  supporting  legs.  The 
ends  of  these  are  bent  around  the  rings 
at  equal  distances.  The  stand  should  be 
covered  with  a  double  thickness  of  screen- 
wire  upon  which  the  vessel  to  be  heated 
is  placed.  The  stand  should  be  of  the 
proper  height  in  relation  to  the  heater 
(lamp  or  Bunsen  burner).  This  stand  is 
illustrated  in  Fig.  1.  A  funnel  stand  is 
shown  in  Fig.  2  and  a  test-tube  stand  at 
Fig.  3. 

An  inexperienced  visitor  to  your  labora- 
tory will  be  mystified  and  his  admiration 
increased  when  you  unconcernedly  dip  a 
piece  of  copper  into  a  liquid  in  a  bottle 
and  bring  it  out  coated  with  what  seems 
to  be  silver.  The  liquid  is  prepared  by 
dissolving  a  drop  of  mercury  in  a  little 
nitric  acid. 

If  some  paper  that  has  been  soaked  in 
starch  solution  and  dried  is  dropt  into  a 
mixture  of  sulfuric  acid  and  potassium 
permanganate,  it  will  flash  several  times 
and  throw  a  very  light  black  residue  for 
several  inches.  This  experiment  looks  like 
a  miniature  volcano. 

Invisible  ink  may  be  made  by  diluting 
one  part  sulfuric  acid  with  twenty  parts 
water.  This  ink  is  visible  only  when 
heated  very  hot. 

Contributed  by        A.  C.  SIMPSON. 


Several     Useful    Wrinkles    for    the  Young 
Chemist  Are  Here  Suggested.    The  Stands 
Shown  Can  All  Be  Made  of  a  Piece  of  Wire, 
Properly  Bent. 


PERCENTAGE  SOLUTIONS. 

Many  persons  appear  to  find  a  difficulty 
in  working  with  solutions  containing  so 
much  per  cent  of  an  ingredient.  There  is 
no  reason  why  confusion  should  ensue,  for 
percentage  solutions  are  as  easy  to  pre- 
pare as  those  whose  constitution  is  other- 
wise exprest,  neither  is  there  any  greater 
difficulty  in  diluting  to  some  weaker  per- 


centage strength.  The  following  points  are 
worth  bearing  in  mind : 

To  convert  percentage  strength  into 
ounces  per  pint,  divide  by  5.  Thus,  20  per 
cent  -r-  5  =  4  oz.  to  the  pint. 

To  convert  ounces  per  pint  to  percentage 
strength,  multiply  by  5.  Thus,  5  oz.  to  the 
pint  X  5  =  25  per  cent  strength. 

The  rule  for  diluting  is  equally  simple. 
To  dilute  a  25-per  cent  solution  to  15  per 
cent,  take  15  parts  of  the  former  and  add 
sufficient  water  to  make  up  to  25  parts 
(ounces,  cubic  centimeters,  or  otherwise). 
Or,  to  put  it  in  general  terms,  for  the  rule 
applies  to  all  strengths,  to  dilute  a  solution 
of  A  per  cent  strength  to  make  one  of  B 
per  cent  strength,  take  B  parts  of  the  strong 
solution  and  add  water  to  make  A  parts  in 
all. 

Contributed  by  H.  J.  GRAY. 


THAT  TEST  FOR  FREE  AMMONIA. 

In  the  May,  1917,  issue  of  your  magazine, 
you  publisht  an  article  written  by  W.  R. 
Spurrier,  on  "Chemical  Experiments." 

In  experiment  number  seven,  Mr.  Spur- 
rier calls  attention  to  Phenolphthalein  be- 
ing a  test  for  free  Ammonia.  As  this  is 
decidedly  wrong,  kindly  publish  the  follow- 
ing experiment  and  test,  lest  some  young 
chemist  be  misled. 

(1)  — Experiment  proving  that  any  alka- 
line solution  will  turn  a  bright  red  when 
Phenolphthalein  is  added. 

Make  up  a  weak  solution  of  Ammonia 
water  (about  five  or  six  drops  of  Aqua 
Ammonia  to  four  ounces  of  water),  a  few 
drops  of  Phenolphthalein  (25%  Alcoholic 
solution)  will  turn  this  solution  to  a  bright 
red.  Neutralize  this  solution  by  adding 
concentrated  Hydrochloric  acid  (HC1), 
drop  by  drop,  until  it  is  again  clear.  (NH« 
OH  +  HC1  =  NH4C1  +  H20.)  If  a  small 
piece  of  Potassium  metal  (K),  be  dropt  in 
this  clear  solution,  it  will  burn  and  at  the 
same  time  slowly  redden  the  solution  again. 
Try  a  fresh  solution,  using  another  alkali 
than  Aqua  Ammonia,  (NH4OH),  eliminat- 
ing the  Potassium  metal,  (K),  and  note  re- 
sults. 

Caution : — 
Handle  Potassium  metal  with  forceps. 
Keep  face  from  solution  when  adding  the 
metal,  as  a  small  explosion  frequently  oc- 
curs. Do  not  allow  any  water  to  come  in 
contact  with  K,  while  handling  it. 

(2)  — Test  for  free  Ammonia  (NH8)  or 
Ammonium  compounds  (NIL — ). 

Mix  unknown  with  any  hydroxid,  pre- 
ferably Sodium  Hydroxid  (NaOH),  if  a 
solid,  add  enough  water  to  cover  the  same 
in  a  test  tube.  Heat  gently,  test  the  gac 
that  is  given  off,  by  holding  a  piece  of  paper 
which  was  previously  dipt  in  concentrated 
Hydrochloric  acid  (HC1),  over  mouth  of 
test  tube.  If  Ammonia  is  present,  white 
fumes  will  appear.  Moistened  red  litmus 
paper  will  turn  blue  when  held  over  mouth 
of  test  tube. 

The  white  fumes  are  solid  particles  of 
Ammonium  Chlorid  (NH4C1).  The  free 
Ammonia  (NH3),  given  off  by  the  Am- 
monium compound  combines  with  the  Chlo- 
rin  (CI),  of  the  Hydrochloric  acid  form- 
ing (NH«C1). 

I  am  a  reader  of  your  excellent  maga- 
zine and  will  continue  to  be  as  long  as  it 
is  printed.   With  apologies  to  W.  R.  Spur- 

"contributed  by     CHAS.  A.  HASEK. 


HOW  TO  CHANGE  THE  TONE  OF 
ANY  GONG. 

Take  the  ordinary  gong  and  cut  a  deep 
groove  or  a  slot  in  it  with  a  hack  saw  and 
it  immediately  changes  the  tone  to  a  cow- 
bell. 

Contributed  by     JULIUS  FRANKS. 


AN  EFFICIENT  PLATE  GLASS 
DRILL. 

In  making  a  static  machine,  it  is  pre- 
ferable to  have  the  glass  plates  drilled  in 
the  exact  center  to  allow  passage  of  the 
spindle  or  axle,  but  the  accomplishment 
of  this  task  is  a  stumbling  block  to  the 


P/umb  bob^S. 

i  ilk  Belt 


Shelf- 


Drill-\  llllll 

Gloss  pfofe^ ^Spool  © 


Simple  Home-made  Apparatus  for  Drilling 
Holes  in  Plate  Glass  for  Static  Machines,  Etc. 

amateur  constructor  and  even  difficult  for 
those  more  skilled  in  workmanship.  How- 
ever, the  simple  drill  apparatus  shown  here- 
with will  do  the  trick  very  nicely  and, 
while  a  little  patience  is  necessary,  the  ex- 
cellent results  will  more  than  compensate 
for  the  time  and  energy  expended. 

First  procure  a  wooden  box,  size  about 
17"  x  10"  x  7"  and  force  out  the  top  and 
bottom  of  the  same,  after  which  construct 
a  shelf  as  shown.  Then  drill  thru  both 
the  top  piece  and  this  shelf  a  hole,  size 
of  which  should  be  of  such  a  diameter 
as  to  allow  the  tube  of  an  ordinary  cur- 
tain rod  to  revolve  freely  and  not  too 
loosely.  Take  the  brass  rod  that  was  in- 
side of  this  tube,  cut  off  a  piece  about  6" 
in  length  and  insert  one  extremity  into  the 
bore  of  a  carpenter's  plumb  bob.  This 
latter  should  be  as  large  as  possible  and 
weigh  at  least  one  pound.  Now,  saw  off 
both  ends  of  an  ordinary  thread  spool  and 
then  glue  together  in  such  a  manner  as  to 
form  a  pulley,  after  which  fasten  rigidly 
to  the  top  of  the  drill,  directly  underneath 
the  plumb  bob.  To  give  greater  speed  to 
the  drill,  make  a  larger  pulley  as  shown 
and  connect  together  by  means  of  a  leather 
belt.  I  may  say,  however,  that  this  method 
will  not  be  found  very  satisfactory,  as  the 
stretching  tendency  of  the  leather  will  in 
a  short  time  cause  the  belt  to  slip  and  thus 
prevent  motion  entirely.  A  better  and 
simpler  way  is  to  merely  hold  the  belt  at 
both  ends,  fit  into  the  groove  of  the  small 
pulley,  and  then  pull  forward  first  with 
one  hand  and  then  the  other,  which  action 
will  give  a  continual  alternating  circular 
motion  to  the  drill. 

When  everything  has  been  completed, 
insert  the  rod,  to  which  the  plumb  bob  is 
attached,  into  the  drill  or  tube,  being  care- 
ful beforehand  to  pour  in  a  small  quantity 
of  emery.  In  as  much  as  this  substance 
is  difficult  to  get  in  a  loose  form,  I  would 
suggest  that  the  reader  do  as  I  did  and 
buy  a  few  sheets  of  regular  emery  paper. 
These  should  first  be  torn  up  in  small 
pieces,  then  put  in  a  metal  pot  or  pan  and 
finally  set  fire  to.  The  paper  will  burn 
away,  leaving  the  emery  grains,  which  can 
be  easily  separated  from  the  paper  ash  by 
sifting  thru  a  fine  strainer.  For  the  pur- 
pose of  raising  the  glass  plate  upward  so 
that  the  full  weight  of  the  plumb  bob  is 
brought  to  bear,  glue  a  large  thread  or 
cotton  spool  to  its  center.  As  the  hole  of 
the  latter  can  be  seen  thru  the  glass,  this 
will  also  act  as  a  guide  in  drilling. 

From  time  to  time,  in  operating  this 
drill,  add  a  little  machine  oil  to  the  emery 
in  order  to  provide  a  lubricant  and  thus 
prevent  the  glass  from  cracking.  Also 
roughen  the  end  of  the  drill  with  a  file, 
so  as  to  give  it  a  sharper  and  therefore 
better  cutting  edge. 

Contributed  by  JOHN  T.  DWYER. 


August,  1917 


THE  ELECTRICAL  EXPERIMENTER 


269 


Our  Amateur  Laboratory  Contest  is  open  to  all  readers,  whether  subscribers  or  not.  The  photos  are  judged  for  best  arrangement  and  efficiency 
of  the  apparatus.  To  increase  the  interest  of  this  department  we  make  it  a  rule  not  to  publish  photos  of  apparatus  unaccompanied  by  that  of  the  owner.  Dark 
photos  preferred  to  light  toned  ones.  We  pay  each  month  $3.00  prize  for  the  best  photo.  Make  your  description  brief  and  use  only  one  side  of  the  sheet. 
Address  the  Editor,  "With  the  Amateurs"  Dept. 


$15.00  Cash  in  Prizes.   Get  Busy,  Boys!!! 

Here  is  your  chance  to  win  a  cash  prize  for  a  few  minutes'  brain  work.  The  big  question  now  confronting  every  radio 
amateur  is — "What  can  I  do  with  my  wireless  apparatus?"  To  help  the  more  than  400,000  loyal  radio  students  and  en- 
thusiasts to  apply  their  knowledge  and,  most  important  of  all,  to  utilize  their  instruments  for  some  practical  electrical  or 
communication  purpose  other  than  wireless,  we  shall  pay  two  prizes — one  of  $10.00  and  one  of  $5.00  respectively,  for  the 
best  suggestion  as  to  "what  to  do  with  your  radio  set  during  the  war."  Be  brief ;  100  to  200  words  should  tell  your  story. 
Remember — it's  the  "idea"  that  counts.  Get  busy  at  once,  boys,  as  we  want  all  suggestions  in  by  July  25th,  at  the  latest,  so  that 
the  results  can  be  announced  in  the  September  number  of  The  Electrical  Experimenter.  And  don't  forget  we  must  have 
thoroly  "practical"  ideas.   Address  the  Editor,  Radio  Problem  Contest. 


A  GROUP  OF  REPRESENTATIVE  AMERICAN  AMATEUR  RADIO  STATIONS. 
Radio  Stations  of,  5 — J.  A.  GJelhaug,  C.  E.  Baudette,  Minn.  (Prize  Winner);  1— Seefred  Bros.,  Los  Angeles,  Cal.;  2 — Greer  W.  Peck,  Spring- 
field, Tenn.;  3 — George  M.  Stuff,  So.  Auburn,  Nebr.;  A — Leo  Hirsch,  Columbus,  Ohio;  6 — Robert  A.  Gerhard,  Lehighton,  Pa.;  7 — Everett  Crump, 
Columbus,  Ind.;  8 — Donald  S.  Bennett,  Wollaston,  Mass.;  9 — Maurice  Pollack,  Chicago,  III.;  10— Charles  Cross,  Oakland,  Cal.;  11 — L.  H.  Cook, 

Mexico,  N.  Y. 


270 


THE  ELECTRICAL  EXPERIMENTER 


August,  1917 


TESLA'S  VIEWS  ON  ELECTRICITY 
AND  THE  WAR. 

(Continued  from  page  230) 

"At  the  time  of  those  tests  I  succeeded 
in  producing  the  most  powerful  X-rays 
ever  seen.  I  could  stand  at  a  distance  of 
100  feet  from  the  X-ray  apparatus  and  see 
the  bones  of  the  hand  clearly  with  the  aid 
of  a  fluoroscope  screen ;  and  I  could  have 
easily  seen  them  at  a  distance  several  times 
this  by  utilizing  suitable  power.  In  fact, 
I  could  not  then  procure  X-ray  generators 
to  handle  even  a  small  fraction  of  the 
power  I  had  available.  But  I  now  have 
apparatus  designed  whereby  this  tremen- 
dous energy  of  hundreds  of  kilowatts  can 
be  successfully  transformed  into  X-rays." 

"Could  these  ultra-powerful  and  unusu- 
ally penetrating  X-rays  be  use_d  to  locate 
or  destroy  a  submarine  with.''"  I  inter- 
jected. 

"Now  we  are  coming  to  the  method  of 
locating  such  hidden  metal  masses  as  sub- 
marines by  an  electric  ray,''  replied  the 
electrical  wizard.  "That  is  the  thing  which 
seems  to  hold  great  promises.  If  we  can 
shoot  out  a  concentrated  ray  comprising  a 
stream  of  minute  electric  charges  vibrating 
electrically  at  tremendous  frequency,  say 
millions  of  cycles  per  second,  and  then 
intercept  this  ray,,  after  it  has  been  re- 
flected by  a  submarine  hull  for  example, 
and  cause  this  intercepted  ray  to  illuminate 
a  fluorescent  screen  ( similar  to  the.  X-ray 
method)  on  the  same  or  another  ship, 
then  our  problem  of  locating  the  hidden 
submarine  will  have  been  solved. 

"This  electric  ray  would  necessarily  have 
to  have  an  oscillation  wave  length  extreme- 
ly short  and  here  is  where  the  great  prob- 
lem presents  itself ;  i.e.,  to  be  able  to  de- 
velop a  sufficiently  short  wave  length  and 
a  large  amount  of  power,  say  several  hun- 
dred thousand  or  even  several  thousand 
horse-power.  I  have  produced  oscillators 
having  a  wave  length  of  but  a  few  milli- 
meters. 

"Suppose,  for  example,  that  a  vessel  is 
fitted  with  such  an  electric  ray  projector. 
The  average  ship  has  available  from  sav 
10,000  to  15,000  H.P.  The  exploring  ray 
could  be  flashed  out  intermittently  and  thus 
it  would  be  possible  to  hurl  forth  a  very 
formidable  beam  of  pulsating  electric  ener- 
gy, involving  a  discharge  of  hundreds  of 
thousands  of  horse-power.  The  electric 
energy  would  be  taken  from  the  ship's 
plant  for  a  fraction  of  a  minute  only,  be- 
ing absorbed  at  a  tremendous  rate  by  suit- 
able condensers  and  other  apparatus,  from 
which  it  could  be  liberated  at  any  rate  de- 
sired. 

"Imagine  that  the  ray  has  been  shot  out 
and  that  in  sweeping  thru  the  water  it  en- 
counters the  hull  of  a  submarine.  What 
happens?  Just  this: — The  ray  would  be 
reflected,  and  by  an  appropriate  device  we 
would  intercept  and  translate  this  reflected 
ray,  as  for  instance  by  allowing  the  ray  to 
impinge  on  a  phosphorescent  screen,  acting 
in  a  similar  way  to  the  X-ray  screen.  The 
ray  would  be  invisible  to  the  unaided  eye. 
The  reflected  ray  could  be  flatly,  inter- 
cepted by  the  one  or  more  f^J^s  'o  the 
fleet;  or  secondly,  it  would  ~be  possible  for 
the  ship  originating  the  ray  to  intercept  the 
refracted  portion  by  sending  out  the  ray 
intermittently  and  also  by  taking  advantage 
of  what  is  known  as  the  after-glow  effect, 
which  means  that  the  ray  would  affect  the 
registering  screen  an  appreciable  time  after 
its  origination.  This  would  be  necessary 
to  allow  the  ship  to  move  forward  suffi- 
ciently to  get  within  range  of  the  reflected 
ray  from  the  submarine,  as  the  reflection 
would  not  be  in  the  same  direction  as  the 
originating  ray. 

"To  make  this  clearer,  consider  that  a 
concentrated  ray  from  a  searchlight  is 
thrown  on  a  balloon  at  night.    When  the 


spot  of  light  strikes  the  balloon,  the  latter 
at  once  becomes  visible  from  many  differ- 
ent angles.  The  same  effect  would  be  cre- 
ated with  the  electric  ray  if  properly  ap- 
plied. When  the  ray  struck  the  rough  hull 
of  a  submarine  it  would  be  reflected,  but 
not  in  a  centrated  beam — it  would  spread 
out;  which  is  just  what  we  want.  Suppose 
several  vessels  are  steaming  along  in  com- 
pany ;  it  thus  becomes  evident  that  several 
of  them  will  intercept  the  reflected  ray  and 
accordingly  be  warned  of  the  presence  of 
the  submarine  or  submarines.  The  vessels 
would  at  once  lower  their  nets,  if  so  equipt, 
order  their  gun  crews  to  quarters  and  dou- 
ble the  look-out  watch.  The  important 
thing  to  know  is  that  submarines  are  pres- 
ent.   Forewarned  is  forearmed ! 

"The  Teutons  are  clever,  you  know; 
very,  very  clever,  but  we  shall  beat  them," 
said  Dr.  Tesla  confidently.  [It  may  be  of 
interest  to  our  readers  to  know  that  several 
important  electrical  war  schemes  will  short- 
ly be  laid  before  the  War  and  Navy  De- 
partments by  Dr.  Tesla,  the  details  of  which 
ice  naturally  cannot  now  publish.] 

BLINDING  THE  SUBMARINE. 

(Continued  from  page  235) 

foredoomed  to  failure.  To  counteract 
strong  sunlight  on  a  silvery  dazzling  ocean 
requires  a  very  strong  light  as  every  sailor 
knows.  Also  if  the  periscope  is  two  or 
more  miles  off,  a  small  searchlight  would 
hardly  be  noticed  by  the  U-boat  com- 
mander, even  if  trained  full  on  him.  For 
that  reason  only  a  very  powerful  light  will 
do.  Perhaps  large  parabolic  mirrors  to 
reflect  the  sunlight  could  be  used  with  fair 
cloudless  skies,  for  there  is  no  stronger 
and  more  blinding  light  than  sunlight.  On 
a  clear  day  this  would  be  perhaps  prefer- 
able to  using  electric  searchlights.  At  any 
rate  the  plan  is  not  an  expensive  one  and 
is  certainly  worth  trying,  foolish  and  idiotic 
as  it  may  appear  at  first. 

However,  most  of  our  everyday,  me- 
chanical reasoning  is  faulty.  For  thou- 
sands of  centuries  people  fled  in  terror 
from  lightning.  No  "sane"  person  up  to 
Benjamin  Franklin's  time  could  have  been 
induced  to  remain  in  a  house  where  there 
was  a  good  chance  for  lightning  to  strike. 
Most  preposterous  of  all,  no  one  would 
have  been  crazy  enough  to  deliberately 
seek  shelter  in  a  house  where  he  knew  in 
advance  that  the  lightning  would  strike, 
nine  chances  out  of  ten.  The  idea,  of 
standing  right  under  the  lightning  for  pro- 
tection ! !  Nevertheless  people  got  over 
their  foolish  notions  when  Benjamin 
Franklin  began  sticking  lightning  rods  on 
their  houses.  Today  the  lightning-rod  pro- 
tected skyscraper  is  hit  frequently  by  thun- 
derbolts, and  people  are  so  used  to  it  that 
they  much  rather  stay  in  a  skyscraper  than 
venture  into  the  open  during  an  electric 
storm.  It  is  safer  right  under  the  light- 
ning. _ 

It  is  just  so  with  the  searchlight  plan 
outlined  above.  Its  very  apparent  danger 
is  its  safety.    Think  it  over. 

WOMEN   RADIO   OPERATORS  TO 
AID  UNCLE  SAM. 

(Continued  from  page  238) 

charge  of  the  Western  Union's  branch  in 
the  Leader-News  building  is  supervising 
instructor  in  the  telegranh  room,  and  a 
real  efficient  pedagog  she  is,  too. 

Applicants  for  membership  are  required 
to  give  their  vocation,  their  own  and  pa- 
rents' nationality,  their  residence  in  the 
city,  and  education.  The  application  blank 
states,  however,  that  the  applicant  incurs 
no  obligation.  There  is  no  expense  what- 
ever attached  to  the  training.  If  women 
are  placed  thru  their  training  in  railroad 


service,  it  will  doubtless  require  that  they 
leave  the  city  and  take  up  work  in  small 
railroad  stations.  At  least,  that  will  be 
where  the  shortage  of  men  employees  will 
be  most  felt.  Mr.  Newman  expects  to 
have  at  least  one  hundred  telegraph  oper- 
ators and  a  score  of  wireless  operators 
qualified  to  take  positions  at  the  expiration 
of  the  present  terms. 

ELECTRIC  SUBMARINE  FORTS  TO 
DESTROY  SUBMARINES. 

(Continued  from  page  231) 

Ordinarily  the  device  would  be  lowered 
into  the  sea  from  on  board  of  a  suitable  ves- 
sel after  the  storage  batteries  are  charged, 
the  operator  took  his  seat  and  the 
cylinder  has  been  closed  carefully  water- 
tight from  outside.  Suspended  from  a 
wire  rope  the  steel  unit  would  slowly 
descend  to  the  bottom  of  the  sea  and  the 
operator  would  himself  feel  nothing  of  the 
ever-increasing  pressure  of  the  water,  but 
could  comfortably  observe  his  surround- 
ings by  turning  on  the  light  projector 
and  rotating  the  device  round  its  vertical 
axis.  Through  the  telephone  he  would  at 
all  times  remain  in  direct  contact  with 
the  vessel,  could  at  any  moment  stop  the 
lowering  of  the  device,  the  shock  of  which 
when  striking  the  ground  would  be  ab- 
sorbed by  a  shock  absorber  arranged  at 
the  bottom  of  the  device  and  ending  in  a 
ball,  and  arrived  near  a  sunken  vessel  he 
could  conduct  and  direct  by  means  of  the 
telephone  any  possible  salvage  operations. 

For  military  purposes,  however,  this  de- 
vice can  be  adapted  to  contain  at  the  same 
point  in  place  of  the  camera  a  special 
arrangement  of  short  torpedo  tubes,  each 
of  which  contains  a  special  short-range 
torpedo  which  can  be  discharged  at  any 
moment  by  the  operator  simply  by  pressing 
a  corresponding  electric  button,  as  soon 
as  he  detects  a  passing  submarine  and  has 
his  device  adjusted  in  the  right  direction. 

For  such  protective  and  defensive  pur- 
poses the  inventor  believes  that  a  num- 
ber of  such  cylinders  submerged  across  a 
given  water-way,  across  the  entrance  to 
the  harbor  of  New  York,  for  instance, 
would  doom  to  destruction  any  enemy  sub- 
marine which  would  attempt  to  pass  thru 
submerged.  Each  device  could  be  con- 
nected to  a  floating  buoy  and  anchored 
from  the  bottom  of  the  bay  from  a  special 
heavy  casing  which  would  contain  an  elec- 
trically operated  drum  upon  which  suffi- 
cient cable  would  be  wound  to  allow  the 
operator  to  rise  to  the  surface  and  which 
would  be  controlled  by  the  operator  thru 
a  special  switch.  Thus  the  operator  could 
constantly  oscillate  slowly  up  and  down 
under  the  water  and  rise  every  twelve 
hours  at  a  certain  time  to  the  surface.  A 
small  vessel  could  at  the  same  hour  pass 
from  one  buoy  to  the  other,  open  the 
cylinder  as  soon  as  its  top  would  appear 
above  water,  let  the  operator  out  and  an- 
other take  his  place.  Where  it  is  possible 
the  electric  current  necessary  could  be  sup- 
plied by  an  electric  cable  running  from 
shore  to  all  anchors  and  up  into  the  devices 
in  place  of  the  storage  batteries  and  also 
telephone  connections  could  be  established 
in  the  same  way  between  all  cylinders 
submerged  and  a  coast  station  (fort)  so 
that  the  operators  could  report  at  once 
everything  of  importance. 

"Submarine  chasers  may  be  of  great 
value,"  says  Mr.  Hartman,  "but  they  have 
to  limit  their  field  mainly  to  the  surface  of 
the  water  as  they  cannot  see  a  submarine 
which  is  running  submerged  at  a  certain 
depth ;  especially  at  night-time.  It  is  more 
easy  for  a  submarine  commander  to  see 
the  shadow  of  any  dangerous  small  craft 
from  below  the  water  thru  special  lenses 
than  to  see  the  submarine  at  a  certain 
depth." 


August,  1917 


THE  ELECTRICAL  EXPERIMENTER 


271 


QUESTION  BOX 


This  department  is  for  the  sole  benefit  of  all  electrical  experimenters.  Questions  will  be  answered  here  for  the  benefit  of  all,  but  only 
matter  of  sufficient  interest  will  be  publisht.    Rules  under  which  questions  will  be  answered: 

1.  Only  three  questions  can  be  submitted  to  be  answered. 

2.  Only  one  side  of  sheet  to  be  written  on;  matter  must  be  typewritten  or  else  written  in  ink,  no  penciled  matter  considered. 

3.  Sketches,  diagrams,  etc.,  must  be  on  separate  sheets.  Questions  addrest  to  this  department  cannot  be  answered  by  mail  free  of  charge. 

4.  If  a  quick  answer  is  desired  by  mail,  a  nominal  charge  of  25  cents  is  made  for  each  question.  If  the  questions  entail  considerable  re- 
search work  or  intricate  calculations  a  special  rate  will  be  charged.  Correspondents  will  be  informed  as  to  the  fee  before  such  questions  are 
answered. 


WIRING  DIAGRAM. 

(812.)  David  Langstrom,  Chicago,  111., 
desires  : 

Q.  1.  How  are  the  wiring  connections 
made  for  the  Fleming  combined  voltmeter 
and  ammeter  method  of  measuring  power 


the  arc  furnaces.  Only  the  direct  current 
can  be  used  in  furnaces  dependent  partly 
or  wholly  upon  the  chemical  effect  of  the 
current,  as  in  the  production  of  aluminum. 


Connections  of  Apparatus  for  Measuring  the 
Power    in    A.    C.    Circuits    by    the  Fleming 
Method. 

in  an  alternating  current  circuit? 

A.  1.  The  diagram  herewith  gives  the 
proper  connections.  The  true  watts  will 
be  equal  to : 

w  =  (Ai=-A=-(rT)x-; 

Where  W  =  true  watts 

Aj=  Indication  of  generator  cur- 
rent 

A  =  Current  consumed  by  load 
V  =  Voltage  across  generator 
If  the  voltmeter  V,  takes  an  appreciable 
amount  of  current,  it  may  be  tested  as 
follows :  Disconnect  R  and  V  at  Y,  and 
see  that  A  and  Ai  are  alike ;  then  connect 
R  and  V  at  Y  again  and  disconnect  the 
load.  Ai  will  equal  current  taken  by  R 
and  V  in  parallel. 

Q.  2.  Why  is  the  active  pressure  in  phase 
with  the  current? 

A.  2.  The  pressure  used  in  overcoming 
resistance  is  from  Ohm's  law,  E  =  RI. 
Hence,  when  the  current  is  zero,  E  is  zero 
and  when  the  current  is  a  maximum  E  is 
a  maximum.  Hence,  that  component  of 
the  imprest  pressure  necessary  to  overcome 
resistance  must  be  in  phase  with  the  cur- 
rent. 


FILAMENT  TEMPERATURE. 

(813.)  Paul  Hancock,  Boston,  Mass., 
asks : 

Q.  1.  What  do  you  consider  as  the  tem- 
perature of  an  incandescent  lamp? 

A.  1.  A  carbon  filament  runs  at  1,700  to 
2,100  degrees  Centigrade.  If  the  voltage 
is  too  high  the  lamp  consumes  too  much 
current  and  the  temperature  of  the  fila- 
ment becomes  so  high  that  it  softens  and 
droops  until  it  may  touch  the  glass  bulb 
which  cracks,  allowing  air  to  enter  and 
burn  out  the  filament.  An  abnormally  high 
temperature  also  causes  disintegration  of 
the  filament  and  causes  its  candle-power 
to  drop  off  rapidly.  Tantalum  and  tungsten 
filaments  run  hotter. 

Q.  2.  What  kind  of  current  is  used  in 
electric  furnaces? 

A.  2.  Either  direct  or  alternating  current 
may  be  used  in  incandescent  and  some  of 


REGENERATIVE  AUDION. 

(814.)  Robert  Murphy,  Phoenix,  N.  Y. 
writes : 


M       ODD  PHOTOS  WANTED  AT  pj 
$1.00  EACH!!! 

pj  Now  is  the  time  to  make  your  pj 
pj  Kodak  pay  for  itself  in  a  real  practi-  m 
pj  cal  way.  We  are  after  interesting  pj 
p|  photographs  of  out-of -the- ordinary  pj 
Hi  electrical,  radio  and  scientific  sub-  pj 
pj  jects  and  are  willing  to  pay  $1.00  cash  Pj 
^  for  every  one  we  can  use.  Please  pj 
Pj  bear  in  mind  that  for  half-tone  re-  pj 
=  production  in  a  magazine,  a  photo-  PJ 
pj  graph  should  be  particularly  sharp  pj 
Pj  and  clear.  Of  course,  if  a  subject  pj 
=  happens  to  interest  us  particularly  = 
m  well,  we  can  have  the  photo  retouched.  pj 
Pj  For  the  general  run  of  subjects,  how-  pj 
pj  ever,  it  does  not  pay  to  go  to  such  jjj 
PI  expense.  Therefore,  please  take  pains  Pj 
Pj  to  properly  focus  and  expose  your  pj 
pj  pictures.  It  often  happens  that  a  PI 
HI  really  mediocre  subject  well  photo-  =j 
PI  graphed  wins  approval  over  an  ex-  pj 
111  cellent  subject  poorly  photographed.  pj 
pj  And  don't  send  us  plate  or  film  ''nega-  PI 
==  fives" ;  send  unmounted  or-  mounted  H 
pj  "prints,"  preferably  a  light  and  a  dark  Pj 

pj  As  to  what  to  photograph:  Well,  Pj 
H  that's  hard  for  us  to  say.  We  leave  Pj 
pj  that  up  to  you,  and  every  reader  now  Pj 
Pi  has  the  opportunity  to  become  a  re-  pj 
m  porter  of  the  latest  things  in  the  realm  pj 
=  of  Electricity,  Radio  and  Science.  PJ 
HI  But,  please  remember — it's  the  "odd,  pj 
=  novel  or  practical  stunts"  that  we  are  pj 
p|  interested  in.  Every  photo  submitted  pj 
pj  should  be  accompanied  by  a  brief  de-  pi 
Pj  scription  of  100  to  150  words.  Give  pj 
p|  the  "facts" — don't  worry  about  the  pj 
=  style.  We'll  attend  to  that.  Enclose  Pj 
jjj  stamps  if  photos  arc  to  be  returned  pj 
=  and  place  a  piece  of  cardboard  in  the  jjj 
p|  envelope  with  them  to  prevent  mutila-  pj 
pi  tion.  Look  around  your  town  and  pj 
pj  see  zvhat  you  can  find  that's  interest-  pj 

pj  Address  photos  to — Editor  "Odd  Pj 
pj  Photos,"  Electrical  Experimenter,  ■ 
jjj  233  Fulton  Street,  New  York  City.  pj 

Q.  1.  Do  all  regenerative  receiving  cir- 
cuits change  the  individual  tone  of  spark 
signals  to  a  hiss  when  maximum  ampli- 
fication is  employed?  If  not,  please  give 
diagram  circuit  for  the  de  Forest  round 
Audion,  suitable  for  200-600  meter  spark 
signal  reception,  where  the  individual  spark 
tone  is  retained. 

A.  1.  The  tone  received  on  the  regen- 
erative  Audion   circuit   corresponds  iden- 


tically to  that  of  the  imprest  frequency 
of  the  distant  transmitter.  However,  in 
regards  to  the  hiss  in  the  receiver  of  such 
a  system  this  is  due  to  "overflow"  effect 
("spilling  over")  of  the  Audion  at  the  high 
potential,  which  is  essential  in  a  regenerative 
circuit  and  which  must  be  controlled  in 
order  to  overcome  this  hiss.  This  effect 
is  not  one  which  is  controlled  by  the  dis- 
tant transmitter  but  due  to  local  condi- 
tions inherent  in  the  system,  which  can  be 
eliminated  by  proper  adjustment. 

The  wiring  diagram  for  a  receiver  cap- 
able of  performing  the  duties  in  question 
is  identical  with  the  standard  regenerative 
Audion  circuit  and  which  you  will  find 
given  a  complete  description  in  the  Jan- 
uary, 1916,  issue  of  this  journal. 

Q.  2.  Which  group  of  apparatus  is  best 
suited  for  undamped  wave  reception  from 
foreign  stations,  the  large,  loose  coupler 
using  the  Chamber's  circuit,  or  the  small 
coupler  with  its  loading  coils  and  conden- 
sers ? 

A.  2.  The  large,  loose  coupler  with  its 
accessories,  such  as  condensers,  etc.,  em- 
ploying either  the  Chamber's  or  Armstrong 
circuits  will  be  found  to  give  best  results. 

Q.  3.  In  constructing  an  aerial  for  200 
meter  transmission,  what  spacing  of  wires., 
what  number  of  wires,  and  what  length 
should  they  be,  to  give  160  meters  natural 
wave  length ;  the  aerial  to  be  of  the  "T" 
type  with  leads  taken  from  the  exact  cen- 
ter? 

A.  3.  The  antenna  for  200  meters  should 
consist  of  four  wires,  50  feet  long,  60 
feet  high  and  the  wires  should  be  spaced 
two  feet  apart.  The  160-meter  antenna 
should  consist  of  four  wires  50  feet  long, 
40  feet  high  and  each  wire  spaced  the 
same  as  the  200  meter  one. 


CAPACITY  MEASUREMENT. 

(816.)  J.  Andricks,  St.  Louis,  Mo.,  in- 
quires : 

Q.  1.  What  is  the  simplest  and  yet  ac- 
curate method  for  measuring  the  capacity 
of  a  condenser? 

A.  1.  The  bridge  method  is  the  simplest 


Showing  How  the  Bridge  Method  Is  Applied 
for  Measuring  Condenser  Capacities. 

method  for  measuring  the  capacity  of  a 
condenser.  This  scheme  employs  a  stand- 
ard condenser  and  the  unknown  capacity 

(Continued  on  page  275) 


272 


THE  ELECTRICAL  EXPERIMENTER 


August,  1917 


■RtEst  Patents 


A  Novel  Electric  Projectile 

(No.  1,226,732;  issued  to  Clarence 
W.  White.) 
One  of  the  most  radical  projectile 
designs  that  we  have  come  across, 
and  which  involves  a  novel  applica- 
tion of  electricity.  The  projectile 
is  made  in  several  sections  and  is 


open  thru  the  center  except  for  de- 
tachable base  cap  c.  By  a  clever 
arrangement  of  an  air  propeller  con- 
nected to  a  dynamo,  the  inventor 
causes  several  things  to  happen,  viz., 
— the  cap  c  drops  off  as  soon  as 
the  projectile  is  started  on  its  way; 
a  magnetically  controlled  rudder 
projects  out  at  the  back;  electric  cur- 
rent from  dynamo  is  caused  to  act 
on  a  quantity  of  water  in  the  annu- 
lar chamber  shown,  causing  oxygen 
and  hydrogen  gas  to  be  evolved,  and 
which  is  electrically  exploded  after 
a  pre-determined  time  period.  More- 
over the  projectile  may  be  set  to 
change  its  course,  while  in  flight. 


Radio  Receptor 

(No.  1,226,060;  issued  to  Elmer  E. 
Bucher.) 

Unique  radio  receptor  in  which  1 


represents  the  aerial  circuit,  contain- 
ing a  tuning  inductance  2,  which  is 
connected  to  the  earth  or  a  suitable 
capacity  at  4.  The  aerial  1,  prefer- 
ably consists  of  a  long  horizontal 
conductor  connected  to  the  earth. 
The  free  end  of  the  aerial  being  a 
point  of  maximum  potential,  is  con- 
nected to  a  vacuum  detector  5.  The 
patent  mentions  the  use  of  an  in- 
ductance connected  to  the  filament 
circuit  as  shown;  this  inductance 
being  adjustable. 

Generator     of     Radio  Frequency 
Oscillations 

(No.  1,226,099;  issued  to  Guglielmo 
Marconi.) 

A  generator  of  radio  frequency 


continuous  oscillations  intended  for 
use  in  wireless  telegraphy  and  tel- 
ephony. Several  sene»  of  insulated 
rotary  spark  gaps  with  comprest  air 


blasts  are  used,  and  the  oscillatory 
circuits  are  energized  from  a  D.  C. 
source  a,  controlled  thru  key  b,  and 
inductance  i.  The  condenser  CI  is 
caused  to  discharge  into  condenser 
C2,  which  discharges  into  condenser 
C3,  which  finally  discharges  thru  a 
rotary  gap  d3,  causing  the  oscillation 
transformer  secondary  S,  to  be  pow- 
erfully excited,  and  which  communi- 
cates its  energy  to  the  aerial  circuit 
thru  a  second  oscillation  trans- 
former. / 


Electrical  Toy 

(No.  1,226,835;  issued  to  Allen  B. 
Wilder.) 

An  efficient  and  simple  self-acting 
electrical  device  for  continuously  op- 
erating swinging  bodies  such  as  toy 
birds  and  animals,  advertising  de- 
vices for  window  displays,  etc.  The 
device  is  claimed  to  operate   on  a 


single  dry  cell  and  to  consume  but 
a  very  small  current.  The  illustra- 
tion shows  a  swinging  parrot,  prop- 
erly counterbalanced.  At  the  top 
of  the  upright  stand  is  a  small  case 
containing  a  set  of  electro-magnets 
and  a  pivoted  armature,  provided 
with  a  contact  spring  which  is  actu- 
ated by  the  downward  movement  of 
the  parrot.  As  the  figure  continues 
to  swing  forward,  the  contact  is 
closed,  and  the  electro-magnet  at 
once  attracts  its  armature  which 
throws  the  figure  upward,  and  thus 
the  action  continues  to  repeat  itself. 

Electrical  Piano  Attachment 

(No.    1,229,122;    issued   to  Donald 
Patrick  Muse.) 
A   clever   electrical   piano  attach- 
ment which  permits  of  playing  sev- 
eral  instruments   such  as  a  violin 


whereby  it  is  possible  for  the  musi- 
cian to  cut  out  any  of  the  auxiliary 
musical  instruments  and  their  elec- 
trical playing  attachments. 

Signaling  Device 
(No.  1,223,589;  issued  to  August  J. 
Kloneck.) 
Means  whereby  high  frequency 
oscillations  may  be  produced  and 
controlled  with  greater  efficiency 
than  heretofore.  The  invention  in- 
volves the  use  of  a  special  vacuum 
fi/otv  oat  co// 


Microphone 


bulb  provided  with  a  metal  plug, 
which  may  be  heated  so  as  to  pass 
gas  from  the  atmosphere,  and  thus 
vary  the  degree  of  vacuum.  The 
bulb  also  contains  a  heating  fila- 
ment, the  usual  grids  and  a  small 
blow-out  coil  arranged  within  the 
chamber  so  as  to  control  the  ther- 
mionic currents  by  its  magnetic  field, 
the  strength  of  which  may  be  regu- 
lated by  a  microphone  connected  in 
the  circuit.  The  operation  of  this 
oscillator  is  similar  to  the  arc  type, 
except  that  instead  of  the  arc,  the 
less  luminous  radiation  of  a  larger 
area  of  electrodes  is  utilized,  and 
the  radiation  of  the  current  is  oc- 
casioned by  a  glowing  filament  in 
the  bulb. 


Electrical    Massage    for    the  Ear 

(No.    1,227,476;    issued    to  Albert 
Maurice.) 


Rec 


duiier 


The  apparatus  in  question  con- 
sists of  a  telephone  receiver  con- 
nected with  a  circuit  comprising  a 
battery  and  a  rapidly  interrupted 
switch  or  contact,  such  as  a  buzzer. 


Sound-Producing  Device 

(No.    1,228,639;   issued   to   Erik  C. 
Bayer.) 

A    rather    out    of   the  ordinary 

and  orchestra  bells  in  harmony  with  -— •         --  ' 

a  piano  when  playing  the  latter. 
The  desired  result  is  accomplisht  by 
arranging  electrical  contacts  at  the 
back  of  each  piano  key,  and  which 
control  electric  sounding  devices 
which  may  play  orchestra  bells,  a 
violin,  etc.  A  flexible  cable  carry- 
ing one  common  wire  and  one  addi- 
tional wire  for  each  sounding  in- 
strument, connects  the  piano  with 
the  separate  cabinet  containing  the 
auxiliary  musical  instruments.  The 
inventor    has    provided    a  means 

COPIES  OF  ANY  OF  THE  ABOVE  PATENTS  SUPPLIED  AT  10c  EACH 


sound-producing  device  which  may 
be  used  as  a  telephone  relay  or  as 
a  loud-speaking  telephone.  The  ap- 
paratus produces  acoustic  vibrations 
from  telephone  or  other  currents 
thru  the  medium  of  a  series  of 
tightened  non-magnetic  wires  con- 
nected in  the  circuit  of  the  tele- 
phone transmitter.  These  wires  are 
placed  in  a  powerful  magnetic  field 
maintained  by  the  large  magnetizing 
coil  2.  High  amplification  is  claimed 
with  this  device,  and  by  using  a 
microphone  8,  within  the  sound 
hood  6,  the  device  acts  as  a  tele- 
phone repeater  with  amplifying 
characteristics. 


High  Tension  Electric  Rectifier 

(No.  1,228,405;  issued  to  William 
H.  Chapman.) 
This  invention  is  based  on  the 
fact  that  if  a  sheet  of  paper  is  laid 
on  the  surface  of  a  grounded  metal- 
lic body  and  a  pointed  conductor 
having  an  alternating  charge  of 
several  thousand  volts,  be  brought 
near  the  paper  or  separated  there- 


Rectif/er 
o-f 


Dyn. 


:t9 


it 


Tronsf 


from  by  an  air  space  for  an  instant, 
as  it  is  in  contact  with  the  grounded 
conductor,  the  paper  when  moved 
from  the  surface  of  the  conductor 
will  show  a  very  high  negative 
charge  of  many  times  the  voltage 
of    the    alternating  charge. 

The  two  metal  rolls  are  grounded 
and  as  the  paper  travels  around,  it 
carries  negative  charges  from  "c" 
and  "d"  to  "f"  and  "g."  The  ap- 
paratus in  Fig.  2  is  for  producing 
positive  electricity. 


Radio  Receiving  Apparatus 

(No.  1,228,647;  issued  to  Elmer  E. 
Bucher.) 

The  aerial  connects  to  a  metal 
band  2,  which  slides  along  an  in- 
ductance coil  3,  this  coil  being 
grounded.    The  free  end  of  the  in- 

Senol 


ductance  coil  is  connected  to  the 
grid  of  vacuum  bulb  detector  used 
in  the  manner  shown,  or  a  crystal 
detector  may  be  used  instead.  It  U 
seen  that  electrostatic  coupling  is 
thus  employed  and  in  tuning  such  a 
receiving  set  metal  ring  2,  is 
moved  along  coil  3,  and  also  the 
degree  of  coupling  may  be  varied 
by  contracting  or  expanding  ring  2. 


August,  1917 


THE  ELECTRICAL  EXPERIMENTER 


273 


Phoney  Patents 


Under  this  heading  are  publisht  electrical  or  mechanical  ideas  which 
our  clever  inventors,  for  reasons  best  known  to  themselves,  have  as  yet 
not  patented.  We  furthermore  call  attention  to  our  celebrated  Phoney- 
Patent  Offizz  for  the  relief  of  all  suffering  daffy  inventors  in  this  country 
as  well  as  for  the  entire  universe. 

We  are  revolutionizing  the  Patent  business  and  OFFER  YOU  THREE 
DOLLARS  ($3.00)  FOR  THE  BEST  PATENT.  If  you  take  your  Phoney 
Patent  to  Washington,  they  charge  you  $20.00  for  the  initial  fee  and  then 


you  haven't  a  smell  of  the  Patent  yet.  After  they  have  allowed  the 
Patent,  you  must  pay  another  $20.00  as  a  Anal  fee.  That's  $40.00  tt 
WE  PAY  YOU  $3.00  and  grant  you  a  Phoney  Patent  in  the  bargain,  so 
you  save  $43.0011  When  sending  in  your  Phoney  Patent  application, 
be  sure  that  it  is  as  daffy  as  a  lovesick  bat.  The  dafner,  the  better. 
Simple  sketches  and  a  short  description  will  help  our  staff  of  Phoney 
Patent  examiners  to  issue  a  Phoney  Patent  on  your  invention  in  a 
jiffy. 


PHONEY  PATENT  OFFIZZ 


0TT0MATTICK  DAIRY  WAGON  [Prize  Winner.  $3,001 
Why  Make  Butter  and  Cheese  on  the  Farm?  Such  Antiquated  Rot!  Pour  the  Milk 
In  Funnel  and  Say  "Glddap"  to  the  Hoss.  While  the  Wagon  Moves  on.  a  Belt 
Operates  the  Electrical  Machinery  Which  In  Turn  Churns  the  Butter  and  Cheese 
Machine,  and  by  the  Time  Hick  Hayseed  Gets  to  Market  the  Fresh  Butter  and 
Cheese  Are  Ready.   Simple.  Ain't  It?   Patented:  H.  0.  Wuelflng,  Bloomfield.  Conn. 


OTTOMATTICK    RAIN  ALARM 
This  Patent  Rain  Alarm  Provides  for  a  Dry  Sponge,  Which  When  the  Rain  Ex- 
pands It,  Presses  a  Push  Button;  This  Latter  Operates  the  800  H.  P.  Motor  Which 
Works  a  Loud-Speaking  Drum  Over  Mr.  Sleeper's  Head.    It  That  Don't  Wake  Him, 
There's  a  Feather  Duster  to  Tickle  His  Soles.    Real  Soulful. 

Inventor:   James  Nelson,  Paterson.  N.  J. 


MAN-O-MOBILE 

The  Wasted  Energy  of  Man  Has  Never  Been  Controlled  Efficiently.    By  Making  Him 
Walk  on  Bellows.    We  Get  a  Lot  of  Comprest  Air  In  the  Storage  Tank.    This  Air 
Is  Then  Used  to  Expand  the  Bellows  Behind  the  Knees,  Thus  Propelling  the  Gink 
at  High  Speed.    To  Prevent  Over-speeding  Counterweight  Is  Provided. 

Inventor:  Nameless  (He  Forgot  to  Send  His  Name). 


ROAD-O-MOTOR 

First  We  Take  a  Lot  of  Planks  and  Hinge  Them  Along  the  Road  on  One  End.  Now 
Then,  When  the  Flivvers  Fllwer  By.  the  Planks  Will  Be  Deprest.    Compressing  Air 
In  the  Compression  Pipe-line.    As  Soon  As  the  Fllwer  Passes,  a  Spring  Under  Plank 
Pushes  It  Up  Again.    The  Comprest  Air  Drives  the  Dynamo. 

Inventor:  W.  C.  Holber,  Valdosta,  Ga. 


2  74 


THE  ELECTRICAL  EXPERIMENTER 


August,  1917 


EXPERIMENTAL  CHEMISTRY. 

(Continued  from  page  267) 
quired,  which  yields  a  readily  soluble  salt, 
Sodium    Hydrogen    Sulfate  [NaHSCX]. 

A  higher  temperature  yields  a  Normal 
salt  [NazSO-i].  For  this  reason  moderate 
heat  should  be  used  when  the  acid  is  pre- 
pared in  the  laboratory. 

Even  at  86°  some  of  the  acid  breaks  up 
into  Nitrogen  Peroxid  [N02],  water 
[H,0],  and  Oxygen  [O]. 

2HN03  =  H20    +    2N02       +  O 
Nitric       Water       Nitrogen  Oxygen 
Acid  Peroxid 

This  dissociation  is  made  apparent  by 
the  liberation  of  the  red  fumes,  Nitrogen 
Peroxid  [NO2],  and  these  dissolved  on  the 
acid  impart  a  yellow  or  red  color  and 
increase  its  strength.  It  is  then  called 
Fuming  Nitric  Acid  [sometimes  errone- 
ously called  Nitrous  Acid]  and  is  extremely 
powerful  and  corrosive.  After  a  time  the 
fumes  will  mostly  evaporate,  though  some 
combine  with  any  water  and  oxygen  pres- 
ent and  form  Nitric  Acid. 

Nitric  Acid  is  prepared  commercially  by 
heating  Sodium  Nitrat  and  Sulfuric  Acid 
in  cast-iron  retorts ;  the  vapor  being  con- 
densed in  earthenware  condensers,  cooled 
by   water,   and   collected   in  earthenware 


Apparatus  Used  in  Making  the  Copperas 
Test  for  a  Nitrat.     See  Experiment  No.  88. 


jars.  The  last  jar  is  connected  with  a 
tower  filled  with  coke,  down  which  a  stream 
of  water  is  allowed  to  flow.  The  object 
is  to  recover  the  Nitrogen  Peroxid  pro- 
duced by  the  decomposition  of  the  acid. 
The  retort  has  an  outlet  pipe  from  which 
the  Sodium  Sulfate  can  be  run  when  the 
action  is  completed.  To  reduce  the  amount 
of  Nitrogen  Peroxid  formed  during  the 
decomposition  of  the  Nitric  Acid  by  heat, 
the  stills  are  often  worked  under  a  re- 
duced pressure  to  permit  the  acid  to  come 
off  at  as  low  a  temperature  as  possible. 

If  the  solution  of  Sodium  Nitrat  and 
Sulfuric  Acid  used  to  prepare  the  acid  is 
weak,  water  will  distill  over  first,  but,  if 
strong,  Nitric  Acid  goes  over  first,  an 
acid  of  quite  constant  composition  is  ob- 
tained containing  about  68%  Nitric  Acid, 
which  is  the  commercial  product. 

When  the  acid  is  prepared  as  above,  it 
generally  contains  some  Chlorin,  and  Iodin, 
derivatives  or  the  Chlorids  and  Iodids  as- 
sociated with  the  Niter.  In  some  cases 
some  Sodium  Sulfate,  Sulfuric  Acid  and 
Iron  are  also  carried  over  during  the 
process  of  distillation.  In  order  that  the 
acid  may  be  purified,  it  is  distilled  in  glass 
retorts,  and  the  first  fraction  which  comes 
over  is  put  on  one  side  as  crude  acid  con- 
taining Chlorin  compounds.  When  no  pre- 
cipitate is  observed  upon  the  introduction 


of  the  distillat  in  a  dilute  solution  of  Sil- 
ver Nitrat,  the  receiver  is  changed  and 
the  larger  part  of  the  Nitric  Acid  distilled 
off.  The  residue  remaining  in  the  retort 
contains  the  Sulfates,  Iodin  and  Iron. 

The  acid  can  be  redistilled  from  con- 
centrated Sulfuric  Acid  to  remove  all  the 
water ;  and  the  Nitrogen  Peroxid  can  be 
eliminated  by  permitting  a  current  of  car- 
bon dioxid  to  pass  thru  the  warm  acid 
until  it  is  without  color. 

Professor  Ostwald  has  patents  on  a 
process  "For  the  Oxidation  of  Ammonia 
into  Nitric  Acid"  and  known  as  the  "Ost- 
wald Process." 

Nitric  acid  may  be  prepared  from  the 
air,  three  important  stages  being  involved. 
First,  the  Nitrogen  and  Oxygen  of  the  air 
are  combined  to  Nitric  Oxid : 

N      +      O      =  NO 
Nitrogen       Oxygen        Nitric  Oxid 

Second.  The  Nitric  Oxid  is  permitted  to 
unite  with  more  Oxygen : 

NO        +        O        =  N02 
Nitric  Oxid        Oxygen        Nitrogen  Peroxid 

Third.  The  Nitrogen  Peroxid  thus  ob- 
tained is  then  permitted  to  react  with 
water : 

3N03  +  H,0  =  2HN03  +  NO 
Nitrogen  Water  Nitric  Nitric 

Peroxid  Acid  Oxid 

Properties  : 

Physical. — 1.  Pure  Nitric  Acid  is  a  color- 
less liquid  with  a  specific  gravity  of  1.53 
at  ordinary  temperatures.  Strong  aqueous 
solutions,  as  well  as  the  pure  acid,  slowly 
decompose  when  submitted  to  exposure  to 
light,  forming  water  [H20]  oxygen  [O] 
and  Nitrogen  Peroxid  [N03],  the  latter 
giving  the  acid  a  yellow  color. 

2.  It  is  very  poisonous  and  corrosive, 
possessing  a  sour  tast,  pungent  odor,  and 
acid  reaction. 

3.  The  pure  acid  is  hygroscopic  and  ra- 
pidly absorbs  moisture  from  air. 

4.  It  is  miscible  in  water  in  all  propor- 
tions, and,  like  sulfuric  acid,  a  rise  in  tem- 
perature is  caused  in  the  mixture,  due  to 
the  contraction  of  the  acid  .when  mixed 
with  water. 

5.  It  boils  at  85°  and  freezes  at — 47°. 

6.  It  completely  dissociates  at  about  256° 
into  Water  [H20],  Nitrogen  Peroxid 
[NO2]  and  Oxygen  [O,]. 

Chemical  : 

1.  It  reacts  with  most  metals  and  non- 
metals  to  form  nitrats. 

2.  It  reacts  with  most  compounds,  and 
turns  animal  matter  yellow.  It  readily  re- 
acts with  many  organic  substances,  form- 
ing compounds  of  great  importance.  Thus, 
with  ordinary  glycerine  it  forms  the  com- 
pound known  as  Nitroglycerine,  which,  is 
the  explosive  constituent  of  dynamite. 
Likewise,  with  cellulose,  the  principal  con- 
stituent of  wood-fiber,  forms  Nitro-cellu- 
loses,  which  are  used  in  making  smokeless 
powder.  When  Nitric  Acid  reacts  upon 
Protein  matter,  a  yellow  compound  known 
as  Xanthorprotein  is  formed ;  hence  when 
Nitric  Acid  comes  in  contact  with  the 
skin,  a  yellow  stain  is  produced. 

Nitric  Acid  is  a  strong  oxidizing  agent 
due  to  the  large  percentage  of  oxygen 
which  it  contains,  and  thus  readily  de- 
composes with  evolution  of  Oxygen.  Un- 
der ordinary  circumstances,  in  the  presence 
of  a  substance  readily  oxidized,  the  acid 
decomposes  according  to  the  equation : 

2HNO3     =     H20    +    2NO      +  30 
Nitric  Acid     Water      Nitric   Oxid  Oxygen 

In  such  cases  Oxygen  is  not  evolved,  but 
enters  into  combination  with  the  oxidizable 


substances  present.  In  this  way  Carbon, 
when  heated  with  Nitric  Acid,  is  oxidized 
to  Carbon  Dioxid : 

C    +    20     =  C02 

Carbon       Oxygen  Carbon 
Dioxid 

3.  Practically  all  Nitrats  are  soluble. 

4.  It  does  not  dissolve  Tin  [Sn],  Anti- 
mony [Sb],  Gold  [Au]  or  Platinum  [Pt]. 
It  forms  white  powders  with  Tin  and  Anti- 
mony. 

Uses  : 

1.  The  chief  uses  of  Nitric  acid  are  to 
make  Nitrats,  Nitroglycerine,  Nitroben- 
zine,  Gun  Cotton,  Celluloid,  to  etch  Zinc 
and  Copper,  and,  in  the  laboratory,  to 
prepare  Aqua  Regia,  dissolve  precipitates, 
and  as  an  oxidizer.  The  most  important 
nitrats  are  Potassium  [K],  Sodium  [Na], 
Silver  [Ag],  Barium  [Ba],  and  Bismuth 
[Bi]  ;  also  Nitroglycerine  and  Gun  Cotton. 
The  Potassium  Nitrat  is  used  as  an  in- 
gredient of  Gunpowder ;  the  Sodium  Ni- 
trat in  making  Nitric  acid ;  the  Silver  Ni- 
trat in  Photography,  in  analysis,  indelible 
inks ;  Barium  Nitrat  is  used  in  fireworks ; 
Bismuth  [BiN03[OH]2]  in  medicine. 

So  far,  in  this  series  of  articles,  the 
writer  has  endeavored  to  make  use  of  the 
simplest  of  apparatus,  knowing  that  most 
experimenters  have  not  funds  sufficient  to 
purchase  more  elaborate  apparatus.  In 
this  installment  we  make  use  of  a  glass 
retort.  This  is  essential  to  prepare  this 
acid,  and  will  be  used  again  for  the  prep- 
aration of  other  compounds.  For  the  bene- 
fit of  experimenters  who  desire  to  equip 
a  chemical  laboratory  on  an  economical 
basis,  the  writer  heartily  recommends  the 
use  of  the  apparatus  illustrated  in  Fig. 
75,  which  contains  nearly  all  the  apparatus 
necessary,  with  the  exception  of  a  few  8- 
ounce  bottles,  which  can  be  purchased,  or 
when  an  experiment  calls  for  an  8-ounce 
bottle,  ordinary  jam  bottles  may  be  em- 
ployed with  good  results.  The  apparatus 
shown  may  be  obtained  from  several  of 
our  advertisers. 

EXPERIMENT  NO.  82: 

Fasten  on  an  iron  stand,  or  tripod  [Figs. 
76  to  77]  a  large  ring  on  which  is  placed 
an  iron  gauze  or  tin  plate  and  asbestos. 
Above  this  fasten  a  clamp  having  three 
thumb  screws,  one  of  which  grips  the  ver- 
tical rod,  another  the  arm  clamp,  the  third 
the  tubulure  of  a  250  cc.  glass  retort  hav- 
ing a  sharply  bent  neck  about  25  or  30 
cm.  long  [Figs.  75a-75b].  Ring  and  clamp 
should  be  nearly  parallel  to  the  base  of 
the  stand,  but  the  retort  neck  should  run 
at  right  angles  to  it  [Fig.  76],  and  reach 
within  3  cm.  of  the  bench.  Tightly  fas- 
ten the  three  screws.  The  neck  of  the 
retort  is  then  put  into  a  large,  clean,  empty 
test  tube,  by  lifting  the  entire  stand  and 
contents  by  the  vertical  rod  with  one  hand 
and  adjusting  it  with  the  other.  Place 
the  test  tube  in  a  wide  bottle  or  tumbler, 
so  as  just  to  touch  the  bottom,  readjust- 
ing the  clamps  if  necessary.  Fill  the  bottle 
or  tumbler  nearly  full  of  water.  Now  raise 
the  ring  until  the  asbestos  reaches  the  bulb 
of  the  retort,  which  should  not  be  in  con- 
tact with  any  metal. 

Before  charging  the  retort  remove  it 
from  the  tube  by  lifting  the  stand  with 
one  hand  and  taking  out  the  tube  with 
the  other.  Unclamp  the  retort  by  the 
screw.  Pour  into  the  retort  thru  the  tubu- 
lure, from  a  creased  paper  [Fig.  78],  about 
10  grams  of  not  too  coarse  Sodium  Nitrat 
[NaNOs],  holding  it  with  the  stem  slightly 
pointed  upward  so  as  to  prevent  any  salt 
from  lodging  within  the  neck.  Remove 
(Continued  on  page  285) 


August,  1917 


THE  ELECTRICAL  EXPERIMENTER 


275 


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QUESTION  BOX. 

(Continued  from  page  271) 
is  compared  electrically  by  means  of  the 
standard. 

Q.  2.  Please  give  wiring  diagram  of  such 
a  simple  method  for  measuring  the  capacity 
of  a  condenser? 

A.  2.  The  diagram  gives  the  wiring  con- 
nections. The  resistance  arms  of  the  bridge 
are  represented  by  Ri  and  R2,  while  G  is  the 
unknown  capacity  and  C2  the  standard.  The 
value  of  the  unknown  condenser  is  deter- 
mined by  the  following  equation : 
Ra 

G  =  G  . 

Rr 


ELECTRICAL  ATTRACTION. 

(817.)  Lucius  M.  Turner,  Royston,  Ga., 
wants  to  know : 

Q.  1.  How  to  illustrate  the  experiment  by 
which  the  laws  of  electrical  attraction  and 
repulsion  are  shown. 

A.  1.  There  are  several  methods  by 
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Q.  2.  How  to  make  a  simple  electro-mag- 
net for  use  on  2  dry  cells. 

A.  2.  A  simple  electro-magnet  is  made  by 
winding  several  layers  of  insulated  copper 
wire  upon  an  iron  core,  as  for  instance, 
by  procuring  a  four-inch  carriage  bolt  about 
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A.  1.  The  power  depends  upon  the  pres- 
sure and  current  supplied  to  the  motor, 
the  current  being  regulated  by  the  amount 
of  work  put  upon  the  motor. 

Q.  2.  What  causes  the  long  flash  when 
the  field  circuit  is  opened  after  the  arma- 
ture circuit  is  opened? 

A.  2.  This  is  caused  by  self-induction. 
When  the  current  thru  the  magnet  coil 
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THE  ELECTRICAL  EXPERIMENTER 


August,  1917 


Mesco  Wireless  Practice  Set 

For  Learning  the  Wireless  Code 


The  Practice  Set  comprises  a  regular  tele- 
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For  the  beginner,  the  set  is  of  exceptional 
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his  wireless  outfit  for  setting  the  detector 
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to  control  the  spark  coil. 

Recommended  for  schools,  as  it  gives  ex- 
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The  main  object  of  the  set  is  to  enable  the 
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Every  beginner  needs  one  of  these  sets, 
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List  No.  Price. 
342.    Wireless  Practice  Set,  with  Battery 

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344.    Wireless  Practice  Set  only,  no  bat- 
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will  be  the  induced  E.M.F.  This  tends  to 
maintain  the  current  even  thru  the  air 
gap  as  the  switch  is  opened.  In  the  case 
of  a  shunt  machine  the  E.M.F.  due  to  open- 
ing the  field  circuit  is  likely  to  reach  a 
value  of  several  thousand  volts  and  is 
liable  to  cause  a  spark  to  jump  thru  the 
insulation  and  either  '"ground''  or  "short- 
circuit''  the  field  coil. 


WAVE  LENGTH  DETERMINA- 
TION. 

(819- A.)  C.  King  Davis,  Hickman,  Ky., 
desires  to  know : 

Q.  1.  How  do  you  determine  the  wave 
length  of  instruments  and  aerials? 

A.  1.  Wave  length  of  instruments  and 
aerials  are  determined  directly  by  means 
of  a  wave  meter  or  by  mathematical  cal- 
culation if  certain  relations,  such  as  di- 
mensions, etc.,  of  the  instrument  or  antenna 
are  known.  These  relations  are  substituted 
in  definite  mathematical  formula?  which, 
when  solved,  will  give  the  wave  length  of 
the  instrument  or  antenna. 

Q.  2.  I  have  heard  that  amateur  wire- 
less stations  have  been  prohibited  until 
this  present  war  is  over;  is  this  true? 

A.  2.  Yes. 


MULTIPLE  RADIO  CIRCUIT. 

(820.)  H.  S.  New,  West  Orange,  N.  J., 
inquires : 


across  the  "B"  or  high  tension  Audion 
battery  for  reducing  the  impedance  offered 
to  the  flow  of  the  high  frequency  currents 
which  are  generated  by  the  Audion  when 
in  an  oscillatory  condition. 

CALIBRATION  OF  INSTRUMENT. 

(821.)  John  Olsen,  Jamaica,  L.  I.,  de- 
sires to  know : 

Q.  1.  What  do  you  mean  when  you  speak 
of  calibrating  an  instrument? 

A.  1.  The  calibration  of  an  instrument  is 
the  process  of  determining  the  value  of 
the  current  or  voltage  required  to  move 
the  indicator  to  any  or  all  parts  of  the 
scale.  This  may  be  done  either  in  making 
a  new  scale  or  in  checking  an  instrument 
which  has  been  in  use.  The  calibration 
may,  for  example,  be  a  comparison  with  a 
standard  instrument  or  it  may  require  the 
use  or  construction  of  new  absolute  stand- 
ards. 

Q.  2.  For  what  range  of  resistance  is  the 
ohmmeter   (megger  type)  suitable? 

A.  2.  It  will  measure  resistances  from 
about  5  megohms  (one  megohm  equals  1,- 
000,000  ohms)  down  to  about  1,000  ohms. 
It  is  convenient  for  measuring  the  insula- 
tion resistance  of  wiring  in  houses  that  are 
not  yet  connected  with  the  supply  circuit, 
insulators,  transmission  line  leaks,  etc. 


ROTATING  FIELD  PRINCIPLE. 

(822.)    V.  R.  Sullivan,  Urbana,  111.,  asks: 


Audion 
l  a,S  IS 


L.C^Aer/ol  loading  cod  Deforest '  RJ  II isoo-izewM.  PS 

C  '  Variable  condenser  Ci  =  Variable  condenser  P,S, 

C?  -  j>oi  mf  Arnold  fiofory.  ^/  brass  plates  or  L'L< 

oooo is -.ooi  Turney  Vorio  Variable  D 

d  *ftff    condeoser.oosmf  C*!Var/ob/ecood  Di 

Cs  =Vor/ob/e  cood  oosmf  Ce- Variable  cond  Di, 

ooos  'iz-t  A  .  00002  fo .  0007  mf  Cenera/Radio  Co  P 
II    =  Variometer  De  forest  type  Rd,  indue fa/?ce 
200  M  to  isooM  or  Ayrton  ■  Perry.  _ 
I07-/I .  oi s  to .  25  M/tlinenrys  Ceneral  Radio  Co 
i07  b  25  to  4  Hi  If  henry s  Genera/  Radio  Co 


-Long  wove,  i  *7  Arnold  loose  coupler  indudive  tuner  t/.ooo  me/ers. 
=5hort  wore  i*5-t  Navy  type  Receiving  transformer  ssooM  Radio  ApporafusCo 
=/  * s  Arnold  foose  coupler  Inductive  tuner  ssoo  M. 
•Type  BB  Turney  Crysta/oi  detecfor 

'Liquid  Barn? Iters Ronescon  Crystol  detector  Motional  f/ectric Syn'lg  Co. 
=L  If  Austin  Static  5hunt  Detector  ff/re/ess  Spec/of fy Apparatus  Co. 
=5randes  Navy  fype  Phones  J2oo  ofims 


Deforest  VC.  5-.002S  mf  ror/able  condenser 

f/oi0  fori  able  air  condenser. 005 mf 'Several  ftod/o  Co- 


© 


Interesting  Hook-up  for  Audion,  Which  May  B 
dyne,  Oscillating  Audion  for  Generator,  Ampli 

phone  Generator 

Q.  1.  Would  the  diagram  shown,  by 
using  the  proper  switches,  be  suitable  for 
use  as :  1 

(a)  Fessenden's  Interference  Preventer 

(b)  Fessenden's  Heterodyne  receiver 

(c)  Oscillating  Audion  for  generator 

(d)  Amplifier  for  crystal  detector 

(e)  De  Forest  Audion  bulb  as  generator 
and  transmitter? 

A.  1.  The  circuit  which  you  show  was 
very  ingeniously  worked  out  and  after 
careful  examination,  we  find  that  it  is  satis- 
factory for  accomplishing  the  results  in 
question.  It  would  be  advisable  to  shunt 
a  high  capacity  fixt  condenser  of  2  m.f. 


e  Operated  As  Interference  Preventer,  Hetero- 
fier  for  Crystal  Detector,  and  deForest  Radio- 
and  Transmitter. 

Q.  1.  At  the  E.  E.  show  at  the  University 
of  Illinois,  one  of  the  magnetic  freaks  was 
as  follows:  a  quarter  (25c  piece)  was 
placed  on  a  wooden  base,  somewhat  con- 
cave, over  a  magnetic  field  consisting  of 
three  magnets,  equidistantly  placed,  which 
was  actuated  by  a  three-phase  current. 
When  the  current  was  on,  the  quarter  given 
a  slight  start,  would  spin  indefinitely,  and 
the  direction  could  be  reversed  at  will. 
Please  explain  ? 

A.  1.  The  phenomena  which  explains  the 
action  of  the  rotation  of  the  coin  is  identi- 
cal to  the  fundamental  principle  of  the 
operation  of  the  A.  C.  induction  motor. 


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August,  1917 


THE  ELECTRICAL  EXPERIMENTER 


277 


As  soon  as  the  coin  was  started  in  a  field 
of  a  three-phase  current,  currents  are  in- 
duced in  the  quarter,  which  reproduce  a 
magnetic  field  in  phase  with  the  generated 
current  and  this  field  tends  to  follow  in 
synchronism  with  the  generated  current,  so 
that  rotation  is  evident  in  the  coin. 

Q.  2.  In  the  design  of  a  rotary  quenched 
spark  gap  as  suggested  hy  Dr.  Zenneck,  I 
believe  it  is  necessary  to  revolve  a  wheel  30 
inches  in  diameter  at  a  speed  of  14,400 
r.p.m.  This  wheel  may  be  made  of  either 
an  insulator  or  a  metal.  The  formula  for 
m  v2 

centrifugal  force  is  f  =   and  is  cor- 

r 

rect  for  a  'weight  on  the  end  of  a  weight- 
less string.  What  is  the  formula  for  de- 
termining the  point  of  application  of  the 
force  or  the  point  corresponding  to  the 
center  of  gravity  in  such  calculations?  If 
I  consider  the  entire  weight  of  the  wheel 
at  the  circumference,  the  results  are  im- 
possible. You  may  consider  the  wheel  as 
being  made  from  a  plain,  unwebbed  or  un- 
spoked  wheel. 

A.  2.  You  are  entirely  wrong  in  consid- 
ering the  rotation  of  a  wheel  for  a  rotary 
quenched  spark  gap  at  the  velocity  you 
state.  It  is  necessary  for  such  rotaries  to 
be  revolved  at  a  maximum  speed  of  4,000 
R.P.M.,  which  is  a  normal  speed  for  a 
wheel  of  30  inches  in  diameter  when  prop- 
erly balanced.  There  aren't  any  special 
formulae  for  computing  centrifugal  force 
and  the  equation  which  you  give  will 
hold  true  for  a  mass  revolved  at  any  speed, 
providing  that  the  mass  around  the  cir- 
cumference is  uniformly  distributed. 


SMALL  HIGH  FREQUENCY  COIL. 

(823.)  E.  E.  Doherty,  Dorchester,  Mass., 
inquires  : 

Q.  1.  What  size  wire  should  be  wound 
on  a  small  Tesla  coil  secondary,  and  how 
far  apart  should  the  turns  be  spaced  from 
one  another  ? 

A.  1.  The  secondary  coil  should  be 
wound  with  No.  28  D.  C.  C.  magnet  wire 
and  each  turn  should  be  spaced  from  its 
adjoining  turn  by  a  1/32-inch  air  space.  It 
is  advisable  to  wind  between  turns  a  thread 
which  has  been  soaked  with  shellac  or 
paraffin.  This  will  prevent  considerable 
leakage  between  turns. 

Q.  2.  Would  the  above  coil  work  well  on 
a  one-inch  spark  coil? 

A.  2.  Yes.  However,  it  is  preferable 
that  a  two-inch  spark  coil  should  be  em- 
ployed. 

Q.  3.  About  how  many  glass  plates  4x5 
inches  would  be  needed  for  the  condenser 
on  a  one-inch  spark  coil? 

A.  3.  Ten  plates  will  be  required. 


How  "Staggered"   Windings   Are   Built  for 
Radio  Purposes  So  As  to  Reduce  Distributed 
Capacity. 

STAGGERED  WINDING. 

(824.)  N.  W.  Smith,  London,  Ont, 
Can.,  inquires : 

Q.  1.  Please  state  what  a  staggered  wind- 
ing is? 

A.  1.  A  staggered  winding  is  a  special 
method  of  winding  inductance  coils  so  as 
to  minimize  the  distributed  capacity  of  the 
coil  due  to  its  multiple  layers.  This  method 
is  employed  considerably  in  winding  multi- 


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78 


THE  ELECTRICAL  EXPERIMENTER 


August,  1917 


Be  Prepared. 


This  picture  shows  Chemcraft  No.  2,  which  con- 
tains 32  chemicals  with  complete  apparatus  and 
Instructions  for  working  85  experiments  in  Chem- 
istry and  Chemical  Magic.  Price,  postage  paid. 
$2.50.  West  of  the  Mississippi  and  to  Canada.  $3.00. 


Dealers:   Write  for 


jnts  on  the  Chemcraft 


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layer  coils  for  use  in  radio  work.  It  is 
sometimes  called  "'bank  winding"  and  the 
manner  in  which  the  individual  layers  are 
wound  is  shown  in  a  cross-sectional  view 
given  herewith.  The  numbers  correspond- 
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in  which  it  is  related  to  the  corresponding 
turns  of  the  coil. 


U.   S.   WANTS   RADIO  AUDITING 
CLERK,  ALSO  BOOKKEEPER 
AND  ACCOUNTANT. 

The  United  States  Civil  Service  Com- 
mission announces  open  competitive  exam- 
inations for  auditing  clerk  (radio)  and 
bookkeeper  and  accountant  (radio),  for 
men  only,  on  July  25,  1917.  Five  vacancies 
in  the  position  of  auditing  clerk  at  en- 
trance salaries  ranging  from  $1,000  to  $1,400 
a  year ;  one  vacancy  in  the  position  of 
bookkeeper  and  accountant  at  $1,500  a 
year ;  two  vacancies  in  the  position  of  as- 
sistant bookkeeper  and  accountant  at  $1,000 
a  year,  all  in  the  office  of  Naval  Com- 
munication Service,  Washington,  D.  C,  and 
future  vacancies  requiring  similar  quali- 
fications, will  be  filled  from  these  examina- 
tions, unless  it  is  found  in  the  interest  of 
the  service  to  fill  any  vacancy  by  rein- 
statement, transfer,  or  promotion. 

The  duties  of  the  position  of  bookkeeper 
and  accountant  involve  the  necessary  book- 
keeping work  in  connection  with  both  Gov- 
ernment and  commercial  traffic  handled  by 
the  Naval  Communication  Service  thruout 
the  world,  including  disbursements  to  do- 
mestic and  foreign  Governments  for  such 
traffic. 

Applicants  must  state  in  answer  to  Ques- 
tion 1  of  the  application  form  which  of 
these  examinations  they  desire.  Only  one 
of  these  examinations  may  be  taken  by  the 
same  applicant. 

Applicants  for  the  position  of  auditing 
clerk  must  show  that  they  have  had  at 
least  six  months'  experience  in  auditing 
radio,  telegraph,  and  cable  accounts  in  con- 
nection with  a  communication  service  in- 
volving all  three  methods  of  communica- 
tion. They  should  be  familiar  with  laws, 
regulations,  and  rates  pertaining  to  radio 
telegraph  and  cable  communication  thruout 
the  world.  It  is  desirable  that  they  be  able 
to  operate  a  typewriter. 

Applicants  for  the  position  of  bookkeeper 
and,  accountant  must  show  that  they  have 
had  at  least  six  months'  experience  in 
bookkeeping  and  accounting  work  in  con- 
nection with  radio,  telegraph,  and  cable 
traffic,  and  they  should  be  familiar  with 
the  laws,  regulations,,  and  rates  pertaining 
thereto. 

Applicants  must  have  reached  their  twen- 
ty-first birthday  on  the  date  of  the  ex- 
amination. 

Applicants  must  submit  to  the  examiner 
on  the  day  of  the  examination  their  photo- 
graphs, taken  within  two  years,  securely 
pasted  in  the  space  provided  on  the  ad- 
mission cards  sent  them  after  their  appli- 
cations are  filed.  Tintypes  or  proofs  will 
not  be  accepted. 

These  examinations  are  open  to  all  male 
citizens  of  the  United  States  who  meet  the 
requirements. 

Applicants  should  at  once  apply  for  Form 
1312,  stating  the  title  of  the  examination 
desired,  to  the  Civil  Service  Commission, 
Washington,  D.  C,  or  to  the  secretary  of 
the  United  States  Civil  Service  Board  at 
any  duly  appointed  place.  Applications 
should  be  properly  executed,  excluding  the 
medical  and  county  officer's  certificates,  and 
filed  with  the  Commission  at  Washington  in 
time  to  arrange  for  the  examination  at  the 
place  selected  by  the  applicant.  The  exact 
title  of  the  examination  desired,  as  given 
at  the  head  of  this  announcement,  should 
be  stated  in  the  application  form. 

For  further  information  address  U.  S. 
Civil  Service  Commission,  Washington, 
D.  C. 


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August,  1917 


THE  ELECTRICAL  EXPERIMENTER 


2  79 


THE  RADIO  BOMB. 

(Continued  from  page  247) 
And  then  he  knew — 

Deep,  rumbling  and  sinister,  it  was  the 
roar  of  the  river  straining  sullenly  at  the 
prison  of  ice  which  confined  the  rush  of 
water  coming  down  from  the  tributaries 
far  up  in  the  hills. 

As  he  drest  hurriedly,  he  glanced  out  the 
window  and  saw  to  his  surprise  that  where 
there  had  been  deep  drifts  of  clean  white 
snow,  the  evening  before,  there  were  now 
vast  stretches  of  muddy  earth  criss-crost 
by  rivulets  of  yellow  water  running  to  the 
swollen  river.  Evidently  the  south  wind 
had  done  its  work  well. 

Hastening  down  stairs  he  found  his 
father  pacing  the  length  of  the  kitchen  with 
quick  nervous  strides. 

"Is  it  very  bad,  Dad?"  Dick  asked. 

"Yes,  I'm  afraid  it  is,  Son,"  his  father  re- 
plied anxiously.  "The  river's  so  high  I'm 
afraid  the  ice'll  go  out  any  minute  and — " 

"Joe — oh,  Joe !"  loud  voices  summoned 
imperatively,  and  following  his  father  Dick 
past  out  into  the  store  from  which  the 
cry  had  come. 

"What  do  you  want?"  the  elder  Pres- 
ton asked,  as  he  threw  open  the  doors  and 
confronted  the  group  which  stood  outside. 

Glancing  past  him,  Dick  saw  in  astonish- 
ment old  Tom  Waldon  at  the  head  of  some 
dozen  men  armed  with  shotguns,  rifles  and 
revolvers  ominously  ready  for  use. 

"Are  you  comin'?"  Waldon  demanded, 
opening  his  coat  so  that  the  constable's  star 
could  show  to  even  better  advantage. 

"Coming  where?"  Joe  Preston  asked  in 
surprise. 

"To  get  that  spy !"  old  Tom  retorted. 

Wide-eyed  and  face  pale,  Dick  stared  in 
amazement  at  the  old  constable  and  his 
posse.  Did  they  really  mean  to  attempt  the 
capture  of  Captain  Hardy?  Did  they  mean 
to  apprehend  him  simply  because  of  their 
suspicions?  The  grim  intentness  of  men 
and  weapons  left  no  room  for  doubt. 

"Did  you  get  your  search  warrant?"  he 
managed  to  stammer  out  huskily. 

"We  ain't  got  time  for  no  search  war- 
rant!" old  Tom  shot  back.  "Didn't  you 
hear  that  bomb  last  night?" 

"I  thought  I  heard  some  one  shoot,"  Joe 
Preston  replied. 

"Well,  I  reckon  you  did,"  the  old  man 
cackled,  ironically.  "I'd  been  blowed  to 
pieces  if  I'd  been  fifty  yards  closer  to  that 
pile  o'  drift  down  there  on  the  bend  when 
it  blowed  up.  The  pieces  fell  all  around 
me  just  as  I  was  goin'  home.  Are  you 
a'comin'?" 

"But  I  don't  see — "  Joe  began. 

"Look  here,  Joe  Preston,"  Pete  Bailey 
burst  out.  "Are  you  goin'  to  stand  by  and 
let  that  spy  blow  up  our  houses?  that's 
what'll  be  next.  Tom's  right.  We'd  bet- 
ter get  him  right  now  a'fore  he  gets  a 
chance  to  do  somethin'  else." 

"And  that's  what  I  think  too,"  a  half 
dozen  endorsed. 

"Better  come  along  a'fore  I  have  to 
deputize  you,"  old  Tom  advised  with  a 
threat  in  his  tone. 

Cheeks  pale  and  eyes  staring  in  appre- 
hension, Dick  saw  his  father  gaze  in  per- 
plexity at  the  grimly  armed  group  before 
him. 

"I—"  Joe  began. 

His  words  were  lost. 

With  a  roar  like  the  broadside  of  a 
mighty  battleship,  the  ice  of  the  river  shot 
skyward  in  a  mad  jumble  of  huge  leaping 
cakes,  only  to  fall  back  in  a  crashing  grind- 
ing mass  and  be  swept  crunching  and 
splintering  down  the  stream  on  the  crest 
of  the  yellow  water,  as  it  raced  at  whirl- 
wind speed  down  the  channel  so  suddenly 
freed. 

Paralyzed  by  the  shock  the  group  in  front 


of  Preston's  store  stared  in  bewilderment 
at  the  plunging  rocking  mass  as  it  surged 
wildly  down  the  stream  with  a  terrible 
deafening  din. 

And  then,  as  one  man,  they  turned  in 
terror  to  the  gorge. 

They  had  cause  for  terror,  for  there,  be- 
tween the  high  banks,  the  ice  had  jammed 
in  a  solid  immovable  barrier  squarely  across 
the  stream's  channel. 

As  the  group  stared  open-mouthed  in 
paralyzed  inaction,  it  grew  swiftly,  tower- 
ing higher  and  higher  as  the  swirling  waters 
from  above  swept  down  fresh  masses  of 
ice  to  be  piled  cake  on  cake  as  the  ob- 
struction mounted  steadily  skyward.  Higher 
and  higher  it  reared  itself  and  higher  and 
higher  rose  the  foaming  yellow  waters  be- 
hind it,  striving  in  vain  to  thrust  aside  the 
obstacle  which  blocked  its  path. 

If  it  should  triumph,  if  the  swiftly  widen- 
ing lake  behind  the  jam  should  sweep  down 
on  the  little  clustered  hamlet —  The  group 
in  front  of  Preston's  store  knew  just  how 
long  their  houses  would  survive  that  rush. 

"Dynamite !  Dynamite !"  Pete  Bailey 
shouted,  and  a  half  dozen  men  leaped  to- 
ward the  shack  where  Joe  Preston  stored 
his  supply  of  the  explosive. 

But  even  as  they  leaped  they  knew  that 
no  man  could  live  in  that  heaving  tumult 
long  enough  to  place  a  charge  where  it 
could  blast  the  steadily  mounting  obstruc- 
tion from  the  channel. 

"The  hills!  Run  to  the  hills!"  they 
shouted,  and  around  the  store  and  up  the 
muddy  slope  they  fled  to  the  first  steep 
knoll  where  the  women  and  children  had 
already  gathered  at  the  first  thundering 
break  of  ice. 

But  Dick  Preston  did  not  run.  For  a 
long  moment  he  stared,  fascinated  at  the 
wall  of  ice  which  towered  in  the  gap  re- 
straining the  impending  wall  of  water.  If 
that  jam  could  not  be  broken  before  the 
water  surged  thru  with  its  own  mighty 
strength,  he  knew  just  how  short  would  be 
the  life  of  this  little  village,  his  home.  But 
who  could — 

He  whirled,  dashed  thru  the  store  and 
sprang  up  the  stairs  to  his  room.  At  his 
wireless  table  he  halted,  jammed  the  re- 
ceivers down  over  his  ears,  while  his  fingers 
slammed  in  switches  and  connections. 

Then  with  savage  speed  his  key  tapt  out, 
"H  D,  H  D.  H  D,  D  P,"  the  crackle  of  the 
spark  sounding  dimly  weak  thru  the  deaf- 
ening roar  of  ice  and  water  outside. 

Again  he  repeated  the  call  with  frantic 
speed  and  threw  over  the  aerial  switch. 

"O  K,  D  P,  H  D,"  came  the  reply,  barely 
audible  thru  the  din. 

"Ice  has  jammed  in  gorge.  Can  you — " 
the  white  hot  spark  faltered  and  then  failed. 

With  a  choking  sob  Dick  peered  over  his 
instruments,  trying  wildly  to  locate  the 
trouble.  Then  thru  the  window  he  caught 
sight  of  his  aerial  wires  sagging  limply 
along  the  ground  where  they  had  fallen 
when  a  guy  wire  peg  had  slipt. 

"Dick!  Dick!  Where  are  you,  Dick!" 
he  heard  his  father  calling  in  agonized 
tones,  and  snatching  the  receivers  from  his 
head  he  sprang  up  and  dashed  downstairs 
to  meet  his  parent  leaping  up  in  search  of 
him. 

"Hurry!  Hurry!  It'll  go  any  minute!" 
Joe  Preston  implored  and  together  father 
and  son  raced  up  the  muddy  slope  to  the 
knoll  where  the  population  huddled  in  a 
forlorn  hopeless  mass. 

Would  he  understand?  Had  the  ground- 
ed aerial  made  his  message  unintelligible? 
Over  and  over  Dick  asked  himself  while 
he  sped  to  safety. 

At  the  gorge  he  looked  and  saw  the  ice 
wall  still  mounting  higher  while  the  water 
restrained  behind  it  spread  wider  and 
wider  in  a  huge  menacing  lake. 


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1 


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□  ELECTRICAL  ENGINEER 

□  Electrician 

Q  Electric  Wiring 

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G  Electric  Car  Running 
Q  Heavy  Electric  Traction 

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Q  Surveyingand  Mapping 
Q  MINE  KOREM'N  OR  ENH'R 

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□  RAILROADER 

□  ILLUSTRATOR 

□  DESIGNER 

□  BOOKKEEPER 

□  Stenographer  and  Typist 

□  Cert.  Pub.  Accountant 

□  Railway  Accountant 
ZJ  Commercial  Law 

□  GOOD  ENGLISH 

□  Common  School  Subjects 
J  CIVIL  SERVICE 

□  Railway  Mail  Clerk 

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Present 
Occupation. 

Street 

and  No  


City- 


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280 


THE  ELECTRICAL  EXPERIMENTER 


August,  1917 


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Then  with  a  prayer  on  his  lips,  he  lookt 
eastward  toward  the  mist-hidden  bulk  of 
Pine  Mountain. 

In  an  agony  of  suspense  he  scanned  the 
blurred  clouds  and  after  an  almost  endless 
moment,  caught  the  darker  and  distinct  out- 
line of  an  object  high  up  in  the  heavens. 

For  an  instant  it  appeared  but  a  blotch 
against  the  mist.  And  then  shaking  free 
the  vapor  it  shot  out  into  the  clear  sunshine, 
a  slimly  cylindrical  shape,  the  sunlight  glit- 
tering from  its  two  pointed  ends  as  it 
glided  at  terrific  speed  thru  the  air.  a 
thousand  feet  above  the  earth. 

"Look !  Look !"  Dick  gasped,  and  pointed. 

Straight  as  an  arrow  the  uncanny  thing 
came,  showing  momentarily  a  glimpse  of  a 
humming  propeller  on  the  tiny  car  which 
drove  it  forward  without  the  presence  of  a 
man.  Then  into  the  cloud  of  mist  which 
hung  high  above  the  gorge  it  dove  and  was 
lost  to  sight. 

But  even  as  it  dove  a  huge  column  of 
spray  spouted  skyward  from  the  jam  to 
join  the  hovering  mist-cloud,  and  an  in- 
stant later  a  series  of  six  rapid  reports 
boomed  out  even  above  the  roar  of  ice  and 
water. 

A  minute  afterward  the  mist  drifted  clear 
of  the  gorge  and  there — where  had  been  the 
towering  ice  barrier,  the  people  of  Pine 
Flat  saw  the  river,  yellow,  swift  and  turbu- 
lent to  be  sure,  but  running  free  and  clear 
thru  the  gap  and  down  past  the  hamlet, 
with  a  wide  margin  of  safety  between  water 
and  buildings. 

"You  couldn't  have  placed  them  more  ac- 
curately with  gunfire !"  Dick  cried  enthusi- 
astically. "Why  they  were  right  where 
they  needed  to  be!" 

"I'm  glad,"  the  tall  man  in  overalls 
beamed  happily.  "I  was  a  bit  afraid  of  the 
control.  But  I'm  ready  to  announce  results 
now." 

"I've  already — " 

Dick  stopt  in  amazement  as  the  door  of 
the  cabin  swung  back.  In  the  opening  stood 
old  Tom  Waldon,  mud-smeared,  bedraggled 
and  wet  but  strangely  humble ;  while  at  his 
back  crowded  the  men  of  Pine  Flat,  push- 
ing their  way  inside. 

"Captain  Hardy?"  old  Tom  inquired 
deferentially. 

"Yes,"  Hardy  acknowledged,  returning 
the  stiffly  queer  salute  the  old  man  gave 
him. 

"We've  come  to  tell  you,"  the  old  con- 
stable said,  "that  we're  mighty  thankful 
to  you  for  savin' .  us  by  blowin'  that  ice 
jam  out  o'  the  gorge.  And  more'n  that  we 
want  you  t'  know  we  never  would've  thought 
you  was  a  spy  if  you'd  let  Dick  Preston 
here  tell  us  that  you  was  a  United  States 
signal  corps  officer  inventin'  that  airship 
that  dropt  them  bombs  by  wireless." 


PERPETUAL  MOTION. 

(Continued  from  page  249) 

ing  in  the  oil.  But  try  as  we  might,  the 
rinktum  wouldn't  budge.  Another  bright 
idea — a  few  batteries,  connected  to  the 
dynamo  to  "start  her  off."  Once  she  runs 
we  take  the  batteries  off,  and  the  system 
will  run  under  its  own  power.  No  sooner 
thought  than  done.  We  fetched  the  8  volt 
storage  battery  and  hooked  her  up!  And 
by  jove  it  worked!  Ran  fine,  and  fast 
too.  But  alas,  as  soon  as  the  storage  bat- 
tery was  taken  off,  the  newly  wedded  motor 
and  dynamo  had  a  private  disagreement. 
Both  became  as  obstinate  as  mules — or 
shall  we  say  as  a  newly  married  couple, 
on  their  first  (and  subsequent  spat) — and 
refused  to  budge. 
After  that  several  other  schemes  were 


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August,  1917 


THE  ELECTRICAL  EXPERIMENTER 


281 


tried  out,  but  none  of  them  could  be  classed 
as  even  a  tolerable  success.  Of  course,  no 
one  was  charitable  enough  in  those  days  to 
inform  us  that  in  the  transformation  of 
energy  from  dynamo  to  motor,  and  in  turn 
frcm  motor  to  dynamo,  we  lose  about 
20%  of  our  total  energy,  which  being 
100%,.  And  20  from  100  leaves  80%.  And 
you  can't  buy  a  dollar  for  80  cents — at  least 
not  thru  the  cashier's  window. 

But  ignorance  is  bliss.  So  the  other  day 
while  rummaging  thru  old  papers,  the 
Editor  came  across  "Experiment  79,  not 
tried  out — looks  positively  feasible."  Ex- 
periment 79,  by  the  way,  was  one  of  the 
series  of  schemes  to  make  the  above,  pain- 
fully described  rinktum  work.  And  if  we 
do  say  it  ourselves,  for  a  scheme  evolved 
by  an  11  year  old  school  boy,  it  is  positively 
epatant,  extraordinaire ,  as  our  French 
teacher  would  have  said,  pride  oozing  out 
of  him  by  the  handful,  while  he  spoke. 

But  alas  we  never  had  the  money  to  try 
it  out.  And  what's  more,  we  haven't  got 
it  now.  And  the  way  things  look  with  the 
war,  the  H.C.L.,  and  the  cost  of  high  liv- 
ing, there's  no  telling  that  we  will  ever  get 
a  crack  at  it. 

But  your  Editor,  who  is  far  famed  for 
his  vast  generosity  (when  his  own  pocket- 
book  is  not  concerned)  graciously  donates 
his  great  and  wonderful  "Experiment  79" 
to  all  Bugdom.  Anyone  may  try  the 
scheme,  and  there  is  only  one  string  at- 
tached to  the  offer,  to  wit: 

In  case  it  works,  the  Editor  is  to  get  a 
free  ride  at  least  once  a  week !  Now  that's 
modest,  isn't  it? 

Well  here's  "Experiment  79." 

Build  a  scenic  railroad  in  a  complete 
circle,  as  shown  in  illustration.  Hills  and 
valleys — the  more  the  better — just  like  the 
regular  scenic  railroad.  Now  we  know  as 
a  fact  that  a  car  launched  on  such  a  road 
will  run  the  entire  length  of  the  track — 
almost,  that  is,  it  will  almost  come  back  to 
its  starting  point.  But  not  quite.  Now 
here's  where  the  foxyness  of  the  idea 
crops  out : 

While  coasting  down  hill,  the  car  ex- 
pends a  lot  of  useful  energy.  So  let's  har- 
ness it !  We  simply  install  a  dynamo  in 
the  car,  coupled  to  the  axle  of  the  latter. 
Use  a  third  rail  to  convey  the  energy  to  a 
central  storage  battery.  So  we  see  that 
while  the  cars  coast,  we  accumulate  a  lot 
of  surplus  energy.  Also  the  more  cars  used, 
the  more  energy  we  get.    That's  plain. 

Now  then.  As  the  car  comes  up  the 
home  stretch  it  runs  slower  and  slower, 
and  finally  reaches  a  stage  where  the  dy- 
namo, which  is  "floating  on  the  line"  gives 
forth  no  more  energy  into  the  line.  At  this 
point  the  storage  battery  begins  to  dis- 
charge into  the  dynamo  and  the  latter  then 
must  run  as  a  motor.  No  electrical  en- 
gineer will  deny  this  fact.  So  the  motor 
fed  from  the  storage  battery  will  pull  up 
the  car  over  the  crest,  and  the  play  com- 
mences anew.  If  there's  no  hitch  any- 
where, the  car  will  keep  on  running  till  the 
tracks  are  worn  out ! 

Sounds  perfectly  logical,  doesn't  it?  Now 
why  in  Sam  Hill  don't  it  work? 

EXPERIMENTAL  PHYSICS. 

(Continued  from  page  250) 
the  pole.    He  will  likewise  sit  down  on 
mother  earth  in  great  haste.     (It  may  be 
advisable  at  this  stage  of  th«  experiment 
for  you  to  retreat.) 

EXPERIMENT  34  (See  Fig.  26)  — 
Place  a  card  on  a  table  with  part  of  it 
projecting.  Place  a  coin  on  the  card.  If 
now  the  index  finger  is  rapidly  snapt 
against  the  protruding  end  of  the  card,  the 
card  will  fly  off  and  the  coin  will  tend 
to  remain  at  rest  and  drop  directly  under- 
neath.   With  a  little  practise  one  may  ac- 


quire skill  and  can  place  the  card  on  one 
of  the  fingers  of  the  other  hand  and  per- 
form the  same  experiment. 

EXPERIMENT  35  (Fig.  27)— This 
represents  a  little  Mexican  game  (not 
the  game  of  throwing  the  bull )  which 
can  be  purchased  in  the  five  and  ten  cent 
store.  It  consists  of  five  blocks  in  the 
shape  of  checkers,  together  with  a  wooden 
head,  and  a  wooden  hammer  of  slightly 
smaller  diameter  than  the  blocks.  With  a 
swing  of  the  hammer  G,  block  B  is  sent 
flying  and  head  A  drops  on  block  C.  In 
the  same  manner  blocks  C,  D,  E  and  F, 
are  removed.  Obviously  the  tendency  of 
the  blocks  to  stay  at  rest  makes  this  game 
possible.  Later  one  can  learn  to  skip  a 
block  and  try  to  knock  off  alternate  ones. 
Finally  it  becomes  possible  to  knock  off 
block  F,  without  the  rest  of  the  pile  be- 
ing disturbed. 

EXPERIMENT  36— So  far  we  have 
considered  only  part  of  the  First  Law. 
The  fact  that  mud  flies  off  a  bicycle 
wheel  tangentially  leads  up  to  the  con- 
sideration that  bodies  tend  to  maintain 
not  only  the  amount,  but  the  direction 
of  motion.  It  is  inertia  that  keeps  the  water 
from  falling  out  of  the  pail  when  swing- 
ing it  over  one's  head.  It  is  inertia  that 
makes  it  possible  for  us  to  loop  the 
loop  in  the  scenic  railway  at  the  amuse- 
ment parks.  Inertia  causes  rotating  liquids 
to  move  out  as  far  as  possible  from  the 
axis  of  rotation ;  it  makes  flywheels  burst 
sometimes ;  it  makes  the  diameter  of  the 
earth  at  the  equator  greater  than  at  the 
poles ;  it  makes  the  milk  which  is  heavier 
than  the  cream  move  out  farther  in  the 
cream  separator.  It  causes  the  loop  of  cord 
A  to  assume  the  position  B,  or  a  perfect 
circle  (Fig.  29),  when  rotating  the  cord 
rapidly.  This  is  the  underlying  principle 
of  the  cowboy's  lasso.  An  egg  (good  or 
bad)  provided  it  is  not  a  hard-boiled  egg, 
after  having  its  insides  sucked  out  thru 
a  pin-hole,  has  a  string  attached  to  one  end 
by  the  aid  of  a  piece  of  sealing  wax.  If 
now  the  string  is  twisted  rapidly  so  that 
the  egg  rotates  rapidly,  it  assumes  the  po- 
sition B  because  of  inertia.    (See  Fig.  29.) 

EXPERIMENT  37— If  an  automobile 
engine  exerts  4,000  pounds  pull  on 
an  engine  on  a  level  road,  at  the 
end  of  one  second  the  velocity  ac- 
quired would  be  just  twice  as  great  as  if 
the  engine  exerted  a  2,000  pull.  In  view 
of  this  fact,  Newton's  second  law  could 
be  stated — The  rate  of  change  of  momen- 
tum takes  place  in  the  direction  in  which 
the  force  acts  and  is  proportional  to  it. 

Space  does  not  permit  giving  anything 
but  this  very  simple  experiment.  (See 
Fig.  28.)  By  means  of  thumb  tacks  at- 
tach two  pieces  of  thread  to  a  base  ball 
and  suspend  it  as  shown.  If  the  thread 
is  grasped  at  A  and  pulled  suddenly  it 
will  break  between  A  and  B.  If,  how- 
ever, the  experiment  is  repeated,  pulling 
slowly,  the  thread  breaks  between  C  and  D. 

EXPERIMENT  38—  If  a  small  "Little 
Hustler"  motor  fan  is  placed  on  a 
light  wagon  (Fig.  30)  with  ball-bear- 
ing wheels  and  a  board  is  placed 
in  position  A,  then  when  the  fan  is  started 
nothing  unusual  happens.  If,  however,  the 
board  A  is  removed,  our  little  wagon 
moves  toward  the  right.  Every  action  has 
an  equal  and  opposite  reaction,  and  hence 
when  the  fan  pushes  against  the  air  in 
front  of  it,  the  air  pushes  back  and  if 
the  wagon  is  light  enough  and  the  friction 
at  the  wheels  is  small,  the  wagon  moves. 


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"My  CONSTIPATION  has 
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"My  CONSTIPATION  was 
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THE  ELECTRICAL  EXPERIMENTER 


August,  1917 


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When  the  board  A  is  in  place  the  wind 
from  the  fan  pushes  against  it,  but  since 
both  the  board  and  the  fan  are  attached 
to  the  same  wagon,  no  motion  occurs.  On 
a  calm  day,  if  motoring  rapidly,  we  feel 
a  wind.  Our  pushing  against  the  air  causes 
the  air  to  push  against  us  and  we  get  the 
sensation  of  wind.  The  aeroplane  is  pro- 
pelled by  the  reaction  of  the  air  against 
the  wind  made  by  the  propellers. 

In  the  case  of  a  man  rowing  a  boat, 
the  man  pushes  against  the  oars,  the  oars 
against  the  water.  The  reaction  of  the 
water  against  the  oars  is  transmitted  to 
the  boat,  and  it  moves.  When  one  jumps 
off  a  boat,  the  boat  experiences  a  back- 
ward thrust.  When  a  bullet  is  shot  from 
a  gun  or  a  shell  from  a  cannon,  the  gun 
"kicks"  or  the  cannon  is  pushed  back  by 
the  reaction.  If  the  two  bodies  consid- 
ered are  of  the  same  mass  the  action  and 
reaction  are  easily  seen  to  be  equal  in 
magnitude,  but  otherwise  it  may  be  diffi- 
cult to  see  it  at  first  consideration.  We 
must  remember  that  the  quantity  of  mo- 
tion is  in  each  case  the  product  of  the 
mass  by  the  velocity. 

The  importance  of  Newton's  laws  can- 
not be  overrated,  and  examples  of  their 
application  can  be  found  without  end.  It 
is  suggested  that  the  reader  look  about 
him  for  as  many  examples  of  each  as 
he  may  recognize.  The  writer  will  be  glad 
to  correspond  with  those  further  interested 
in  this  subject. 


"BATS." 

{Continued  from  page  261) 
the  top  of  a  cloth  bag  of  dropsical  shape 
and  knobby  surface,  could  be  truly  loved 
for  its  appearance  by  its  maker  only ;  but 
it  worked  perfectly,  and  faithfully  gave  up 
its  little  trickle  of  "juice"  for  the  operation 
of  our  apparatus.  What  should  we  ever 
have  done  without  it? 

Of  course,  like  all  worldly  things,  it  had 
its  faults.  Sal-ammoniac  is  harmless  to  the 
human  system  ( unless  you  happen  to  get 
it  on  a  cut,  when  it  makes  vou  execute  a 


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inventions.  The  Government  is  ready  to  experiment  with  and  carefully 
consider  any  inventions  which  will  aid  in  winning  and  ending  the  War. 
The  Special  War  Bulletin  just  off  the  press  will  give  you  a  good  idea  of 
What  is  needed.  We  will  send  it  to  you  free  of  charge.  Located  in  Wash- 
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few  capers  and  forget  your  other  troubles) 
but  its  appetite  for  copper  is  unlimited, 
and  its  cunning  hygroscopic  habit  of  creep- 
ing out  of  the  jar  and  spreading  itself 
over  the  surrounding  landscape  does  not 
endear  it  to  any  member  of  the  family, 
from  the  cat  up.  On  returning  from  a  sum- 
mer vacation,  I  have  more  than  once  found 
my  copper  terminals  eaten  off  and  forming 
the  center  of  a  spongy  mass  of  a  beautiful 
grass-green  color,  while  everything  within 
several  feet  was  covered  with  the  damp 
white  deposit  of  sal-ammoniac  crystals.  I 
always  longed  to  try  the  experiment  of  set- 
ting one  of  these  batteries  in  the  midst 
of  a  boundless  plain  and  seeing  how  far 
one  jar-full  of  the  stuff  could  spread  itself 
if  it  had  plenty  of  time  and  room;  I  be- 
lieve it  would  cover  the  earth. 

While  the  Leclanche  battery  was  always 
our  standby,  it  had  its  limitations.  Its 
resistance  was  high,  its  current  of  small 
quantity,  and  on  being  short-circuited  it 
promptly  polarized  and  died.  We  tried 
Bunsen's,  but  they  were  far  too  expensive. 
But  with  the  coming  of  the  telegraph  era, 
we  took  up  gravity  cells,  and  they  soon 
secured  a  warm  place  in  our  hearts.  These 
sturdy  cells  worked  24  hours  a  day,  as 
long  as  the  slightest  color  of  copper  sul- 
fate remained  in  them.  We  were  never 
tired  of  noting  the  clean-cut  line  of  the 
blue  solution,  held  in  its  place  at  the  bot- 
tom of  the  jar  by  its  excess  weight  over 
the  transparent  solution  above — a  differ- 
ence, of  course,  not  apparent  to  the  eye. 

This  battery  piqued  our  inventive  faculty 
because  it  furnished  so  much  more  current 
than  we  needed.  Not  only  when  we  were 
using  the  telegraph,  but  all  the  time  when 
we  were  at  school,  or  in  bed  and  asleep, 
it  plugged  away.  If  one  could  only  econo- 
mize it !  but  it  was  impossible.  If  the 
circuit  was  left  open,  the  blue  solution  rose 
by  diffusion  till  it  directly  attacked  the 
zinc,  when  mud  and  long  strings  of  copper 
metal  began  to  form,  and  soon  the  battery 
was  ruined.  Neither  could  you  economize 
by  lifting  out  the  zinc,  because  again  the 
diffusion  took  place,  and  you  couldn't  put 
it  back  without  raising  all  sorts  of  chemical 
Cain. 

No  use ;  we  had  to  stand  by  and  see  all 
that  beautiful  "juice"  wasted  while  we 
needed  it  elsewhere.  It  manufactured  more 
in  one  day  than  the  Leclanche  cell  did  in 
its  lifetime,  yet  it  was  useless  because  it 
couldn't  be  held  back.  Even  the  similar 
Daniell  cell,  with  its  porous  cup,  couldn't 
be  left  on  open  circuit ;  it  was  necessary  to 
use  up  the  copper  sulfate  on  its  depolariz- 
ing job  faster  than  it  could  spread  by 
diffusion.  All  the  text-book  writers  said 
there  was  no  help  for  it. 

But  text-book  writers  have  never  been 

boys ! 

When  clocks  came  in,  the  demand  be- 
came still  more  pressing.  Here  was  a 
mechanism  which  required  but  little  current, 
to  be  sure.  A  wet  Leclanche  would  run  it 
for  months ;  but  that  only  made  the  gravity 
cell,  in  its  obstinate  generosity,  more  exas- 
perating. A  gravity  cell  would  run  three 
months  on  one  charge  of  sulfate,  produc- 
ing in  that  time  enough  current  to  run  the 
clock  for  60  years  at  the  lowest  calculation. 
If  one  could  only  choke  it  back! 

Fools  rush  in  where  scientists  are  afraid 
of  getting  the  laugh.  In  spite  of  the  text- 
book writers.  Dr.  Daniell  and  the  Lion's 
Den,  I  puzzled  over  ways  to  strangle  up 
that  cell. 

It  first  struck  me  to  confine  the  sulfate 
solution  in  a  non-porous  cup,  and  let  it 
ooze  out  over  the  copper  plate  thru  a  very 
small  hole,  instead  of  exposing  a  great  area 
(Continued  on  page  284) 


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August,  1917 


THE  ELECTRICAL  EXPERIMENTER 


283 


Edited  by  H.  GERNSBACK 

In  this  Department  we  publish  such  matter  as  is  of  interest  to  inventors  and 
particularly  to  those  who  are  in  doubt  as  to  certain  Patent  Phases.  Regular  inquiries 
addrest  to  "Patent  Advice"  cannot  be  answered  by  mail  free  of  charge.  Such  inquiries 
are  publisht  here  for  the  benefit  of  all  readers.  If  the  idea  is  thought  to  be  of  im- 
portance, we  make  it  a  rule  not  to  divulge  details,  in  order  to  protect  the  inventor  as 
far  as  it  is  possible  to  do  so. 

Should  advice  be  desired  by  mail  a  nominal  charge  of  $1.00  is  made  for  each 
question.  Sketches  and  descriptions  must  be  clear  and  explicit.  Only  one  side  of 
sheet  should  be  written  on.   

siderably.  There  is  nothing  hew  in  this  ex- 
periment, which  has  been  performed  by 
various  physicists  over  100  years  ago. 


DETACHABLE  HEEL. 

(166.)  Joseph  Pacyk  of  Glassport,  Pa., 
submits  to  us  a  very  ingenuous  idea  where- 
by an  ordinary  leather  heel  on  a  shoe  can 
be  detached  when  it  is  worn  out,  in  a  very 
simple  manner  thereby  making  it  unneces- 
sary to  take  the  shoes  to  the  shoemaker  or 
repair  shop.  His  idea  is  to  get  the  shoe 
people  to  stock  these  special  heels,  which  can 
then  be  attached  by  any  one  without  any 
tools  whatsoever. 

A.  This  is  a  capital  idea,  and  no  doubt 
a  patent  can  be  obtained..  In  case  nothing 
similar  has  been  patented  before,  and  we 
doubt  there  has,  we  think  a  valuable  patent 
may  result.  We  would  advise  our  corre- 
spondent to  get  in  touch  with  a  patent  at- 
torney. 

Mr.  Pacyk  also  submits  to  us  a  design  of  a 
tooth  brush,  the  idea  being  that  it  could  be 
used  for  brushing  teeth  on  the  inner  side 
of  the  teeth  as  well. 

A.  We  do  not  think  this  idea  is  patent- 
able, and  we  believe  several  brushes  similar 
to  this  one  have  been  in  use. 


SUBMARINE  MINE. 

(167.)    Elmer  Wahl,  of  Carnegie,  Pa 
closes  diagram  and  description  of  a 
exploding  mine  for  harbor  defence, 
mine  is  supposed  to  explode  when  a 


,  en- 
self- 
The 
sub- 


marine comes  in  proximity  to  it.  The  prin- 
ciple is  based  upon  a  highly  magnetized 
needle  which  the  submarine  is  supposed  to 
deflect,  and  then  auxiliary  contacts  cause 
the  explosion  of  the  mine,  or  otherwise  the 
current  for  the  mines  may  be  supplied  from 
the  shore ;  thus,  doing  away  with  the  bat- 
teries in  the  mine  itself. 

A.  We  do  not  favor  the  first  idea  at  all, 
as  it  is  not  practical,  being  too  dangerous  ; 
i.e.,  the  mine  might  explode  prematurely  if 
a  friendly  steamer  came  into  range.  The 
second  idea  is  not  new.  The  United  States 
Navy  is  using  similar  mines  controlled  from 
shore.  We  cannot  give  any  encouragement 
on  these  two  ideas. 


GAS  SPARK  GAP. 

(168.)  Harry  McLaughlin,  Jr.,  Paw- 
huska,  Okla.,  has  made  some  experiments 
with  a  bunsen  burner  and  spark  gap,  and 
found  that  by  means  of  the  bunsen  burner, 
the  spark  can  be  lengthened  out  several 
times  its  original  value.  He  wishes  to  know 
if  this  is  a  new  discovery  and  whether  the 
idea  is  patentable.  Also  if  it  is  to  any  ad- 
vantage in  some  form  of  electrical  appar- 
atus, wireless,  etc. 

A.  Nothing  new  is  suggested  in  the  de- 
vice, which  is  old.  If  you  take  an  ordinary 
candle  and  spark  gap,  and  let  the  spark  go 
across  the  lighted  candle  flame,  the  spark 
will  be  lengthened  considerably.  The  rea- 
son is  that  all  flames  contain  large  amounts 
of  hydro-carbons,  due  to  the  combustion 
of  carbon  or  whatever  other  materials  are 
burnt  up,  and  these  carbon  particles  as  well 
as  the  hot  air  form  a  much  better  conductor 
than  the  common  atmosphere.  This  is  the 
reason  why  the  spark  is  lengthened  out  con- 


SELLING  PATENTS. 

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to  know  the  best  place  to  dispose  of  a  patent. 
Mr.  Jeffries  is  an  electrician  and  has  a  patent 
on  an  electrical  device  which  he  desires  to 
dispose  of. 

A.  The  Electrical  Experimenter  can- 
not officially  give  the  names  of  persons  that 
are  likely  to  buy  electrical  or  any  other  pat- 
ent. The  safest  and  best  way  is  to  adver- 
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our  advertising  columns  or  otherwise  in 
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idea  to  send  copies  of  the  patent  to  adver- 
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THE  ELECTRICAL  EXPERIMENTER 


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"BATS." 

(Continued  from  page  282) 

of  it  to  diffusion.  That  sounds  reasonable, 
doesn't  it?    Well,  here's  what  happened. 

I  set  up  a  cell  as  shown  in  Fig.  1,  my 
glass  sulfate-storage  cup  "S"  having  a  hole 
about  diameter  drilled  thru  the  bottom. 
That  seemed  to  me  pretty  small,  but  bless 
you,  it  was  as  wide  as  a  barn  door  for 
that  elusive  sulfate.  On  open  circuit  it 
serenely  diffused  out  as  tho  my  cup  had 
been  composed  entirely  of  hole. 

This  sulfate  was  evidently  an  animal  that 
had  to  be  stalked  with  care  if  one  wanted 
to  capture  it.  I  cleaned  out  my  storage- 
cup,  and  in  the  bottom,  over  the  hole,  I 
placed  a  dozen  discs  of  filter-paper.  "Now," 
says  I  to  the  sulfate,  "tackle  that  little  ob- 
struction and  see  what  you  make  of  it,  dog- 
gone you."  Another  surprise :  Mr.  Sulfate 
sulked  and  refused  to  emerge  at  all.  I  was 
tickled  to  death  at  first,  because  I  needed 
hardly  any  of  it  for  an  open-circuit  propo- 
sition, and  it  looked  as  if  I  had  it  strangled 
good  and  plenty  for  the  purpose ;  but  as 
days  went  by  and  no  sulfate  appeared  with- 
out, I  concluded  I  had  it  choked  too  much. 
"Well  and  good,"  says  I,  "I've  got  you 
down,  now  I'll  let  you  up  slow."  So  one 
by  one  I  removed  my  filter-paper  discs  until 
only  a  single  one  was  left,  and  what  do  you 
think?  That  one  was  just  as  good,  or  bad, 
as  the  whole  dozen !  In  the  open  air  the 
blue  solution  would  go  thru  nicely,  but 
against  the  pressure  of  the  surrounding 
liquid  it  wouldn't  budge ! 

I  wasn't  disappointed;  in  fact  I  was 
rather  pleased,  because  all  I  had  to  do  was 
to  continue  my  cautious  stalking.  I  took 
a  fine  needle  then  and  pricked  just  one 
little  hole  in  the  filter-paper.  "Now,"  says 
I  to  Mr.  Sulfate,  "there's  a  place  you  can 
crawl  thru,  and  I'll  slowly  enlarge  it  till 
you  can  get  your  head  out,  but  no  more,  so 
don't  you  tease !" 

Is  that  so?  I  heard  what  I  thought  was 
a  gurgle  in  the  battery,  but  it  was  Mr. 
Sulfate  giving  me  the  grand  high  chuckle. 
He  came  out  of  that  needle-hole  as  easily 
as  I  could  get  out  of  the  State  of  Massa- 
chusetts (if  I  wanted  to,  that  is;  of  course 
no  one  would  ever  want  to  do  a  thing  like 
that).  It  was  evidently  either  one  extreme 
or  the  other  with  Mr.  S.,  and  that  choke- 
valve  theory  had  to  be  abandoned. 

All  this  time  my  battery,  electrically, 
worked  to  a  charm,  and  I  could  see  plainly 
that  the  only  problem  was  controlling  my 
supply  of  sulfate.  My  blue-colored  friend 
had  shown  considerable  ability  in  crawling 
out  thru  the  cellar,  but  could  he  climb  out 
the  chimney?  I  plugged  up  the  hole  in 
the  bottom  of  my  storage-cup,  and  offered 
him  a  passage  instead  thru  the  siphon 
shown  in  Fig.  2. 

I  can't  remember  whether  the  sulfate  did 
diffuse  thru  the  siphon  or  not ;  I  think  it 
did ;  but  the  chief  trouble  was  that  bubbles 
of  gas  collected  in  the  top  of  the  siphon 
and  eventually  broke  the  liquid  connection. 
The  next  step  was  to  discontinue  the  siphon 
as  a  siphon,  and  fill  it  with  cotton  wicking, 
so  that  a  connection  between  the  two 
liquids  was  maintained  by  capillarity. 

This  at  last  was  successful.  The  liquids 
did  not  mingle  at  all,  while  the  hydrogen 
atoms  still  .  had  opportunity  to  travel,  as 
they  must,  from  the  zinc  to  the  copper 
plate.  My  battery  gave  a  nice  little  cur- 
rent— very  slight  in  quantity,  of  course,  on 
account  of  its  high  resistance,  but  of  good 
voltage.  It  would  stand  any  length  of  time 
on  open  circuit  without  mixing,  while  if 
put  on  closed  circuit  it  would  get  busy 
all-same  bee,  as  Charley  One-Lung  would 
say,  and  stick  to  its  job  as  long  as  required. 

The  problem  was  now,  while  preserving 
the  same  principle  of  capillarity,  to  reduce 


No.  Hl<  1800 

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it  Is  infinitely  more.  Mr.  H.  Gernsback  who  de- 
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top  of  it  to  hear  its  beautiful  musical  note. 

Tou  will  he  astounded  at  the  wonderfully  clear, 
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or  more  such  sets  in  series  will  afford  no  end  of 
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the  Radiotone  is  already  in  wonderful  demand. 
All  the  interesting  things  as  described  with  our 
C0D0PH0NE  (see  our  big  ad  on  pages  256-7, 
this  issue),  can  be  performed  with  the  Radio- 
tone,  a  key,  a  dry  cell  and  a  phone. 

Radiotone  as  described  each  ^.90 

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THE  ELECTRICAL  EXPERIMENTER 


285 


the  internal  resistance.  The  final  form  to 
which  I  carried  the  cell  is  shown  in  pig.  3. 
This  is  like  Fig.  2,  except  that  the  capil- 
larity is  secured  thru  several  layers  of  bur- 
lap sacking,  straddling  the  entire  edge  of 
the  inner  cup.  This  reduced  the  resist- 
ance to  a  point  where  the  electric  output 
was  sufficient  to  work  a  swinging-magnet 
annunciator-drop  very  well. 

Munn  says  the  idea  is  patentable,  but 
none  of  this  patent  stuff  for  mine.  I  here- 
by turn  the  invention  over  to  Bugdom  for 
improvement.  If  such  a  form  can  be  given 
it  that  the  capillary  mass  is  very  much 
larger,  it  will  give  an  output  big  enough 
for  a  clock;  at  present  it  doesn't,  but  is 
ample  for  any  nigh-resistance  indicating 
device,  electrolytic  detectors,  etc.  As  to  its 
staying  powers,  I  had  one  of  these  cells 
on  open  circuit  in  my  shop  for  four  years, 
testing  it  with  the  annunciator-drop  from 
time  to  time.  At  the  end  of  the  period  the 
liquid  had  evaporated  out  by  a  half,  owing 
to  my  cover  not  being  perfectly  tight;  but 
the  zinc  plate  was  very  little  consumed,  the 
liquid  in  the  outer  jar  was  as  clear  as 
spring-water,  the  blue  solution  remained  in 
the  inner  jar  with  no  diminution  in  the 
sulfate  crystals  I  had  added  to  keep  it 
saturated.  The  current  would  still  work 
the  annunciator-drop,  tho  not  as  vigorously 
as  at  first,  probably  due  to  the  liquid  levels 
being  lower.  I  had  to  leave  the  old  house 
then,  and  as  the  battery  couldn't  be  moved 
the  experiment  was  over. 

Why  don't  you  push  it  along,  Bugs,  just 
to  while  the  time  away  till  they  give  us 
back  the  air?  That  "bat's"  a  handy  little 
thing  as  it  is ;  and  if  you  could  devise 
some  low-resistance  form  that  you  could 
couple  on  to  a  clock  and  run  the  thing 
5  to  10  years  at  a  stretch — well,  s-ay ! 

EXPERIMENTAL  CHEMISTRY. 

(Continued  from  page  274) 
also,  by  the  finger  or  towel,  any  nitrat 
adhering  to  the  tubulure,  as  it  is  liable 
to  crack  the  retort  on  heating.  The  retort 
may  now  be  readjusted  in  position.  Pour 
into  a  tube  about  20  cc.  of  strong  Sul- 
furic Acid  [H2SO4],  and  using  a  glass 
funnel,  so  as  to  keep  the  acid  out  of  the 
retort  neck,  pour  it  into  the  retort.  Rinse 
the  funnel,  replace  the  stopper  in  the  tubu- 
lure, and  readjust  the  retort  in  position. 
Apply  heat  for  10  or  15  minutes,  or  until 
5  cc.  or  more  of  liquid  has  collected  in 
the  test  tube. 

Upon  the  introduction  of  the  Sulfuric 
acid  into  the  retort,  action  will  probably 
commence  at  once,  but  a  gentle  heat  should 
be  applied,  whereupon  the  volatile  Nitric 
Acid  passes  over  and  is  then  collected  in 
the  test  tube  in  the  bottle  or  tumbler, 
which  should  be  kept  cool.  A  few  pieces 
of  ice  may  be  placed  in  the  water. 

The  reactions  which  will  probably  take 
place  are : 

NaN03  +  H2S04  =  HNaS04  +  HN03 
Sodium  Sulfuric  Sodium  Nitric 
Nitrat  Acid         Hydrogen  Acid 

Sulfate 


2NaN03  +  H2S04  =  Na2S04  +  2HNOa 
Sodium       Sulfuric       Sodium  Nitric 
Nitrat  Acid  Sulfate  Acid 

The  reason  for  these  two  equations  are 
more  fully  explained  under  the  heading 
"Preparation"  in  a  previous  paragraph. 

Note  all  phenomena,  fumes,  color, 
whether  or  not  the  color  changes  with 
varying  temperature,  effervescence,  whether 
anything  is  visible  in  the  retort  tube,  color 
of  the  liquid  collected,  etc. 

As  soon  as  the  lamp  is  removed,  pour 
5  or  10  drops  of  Ammonium  Hydroxid 
[NH4OHI  into  a  dish  and  dip  a  small  piece 


of  paper  or  stirring  rod  into  it ;  then  bring 
the  alkaline  paper  or  rod  to  the  tubulure, 
removing  the  stopper  with  a  cloth  if  it  is 
hot.  This  must  be  done  while  the  con- 
tents of  the  retort  are  hot. 

Note  any  action  and  fumes  [whether 
gaseous  or  solid]. 

To  remove  the  collected  acid,  which 
should  be  done  soon  after  the  lamp  is 
taken  away,  lift  the  entire  ring  stand  with 
one  hand  and  with  the  other  grasp  the  test 
tube  by  its  rim  between  the  thumb  and 
forefinger  and  set  it  in  the  rack.  [Use 
great  care  at  all  times  not  to  get  any  of 
this  acid  on  the  flesh  or  clothing,  as  it  is 
very  corrosive.  Let  down  the  ring  stand 
in  such  a  position  that  any  acid  may  drip 
from  the  nozzle  into  the  sink ;  then  raise 
the  retort  to  a  horizontal  position  by 
changing  the  clamp  screw.  Put  a  funnel 
into  the  tubulure  and  pour  water  thru  it 
into  the  retort  bulb  [cautiously  at  first,  if 
it  is  hot,  and  from  a  tube].  Finally  clean 
the  entire  retort,  running  water  several 
times  thru  the  neck,  bulb  and  tubulure. 

EXPERIMENT  NO.  83 : 

Note  the  color  of  the  liquid  obtained  in 
the  preceeding  experiment,  and  if  you 
have  some  of  the  commercial  acid  at  hand, 
compare  with  it  in  this  respect. 

Apply  a  piece  of  litmus  paper  to  the 
liquid  thus  obtained  in  the  preceding  ex- 
periment, and  if  an  acid  is  present  it  should 
give  an  acid  reaction  with  the  litmus. 

Obtain  a  piece  of  colored  cloth  [woolen] 
and  permit  a  few  drops  of  the  acid  to  fall 
upon  it.  Dense  fumes  should  rise  from 
the  cloth,  and  the  cloth  become  discolored, 
as  tho  rotten.  From  this  it  is  obvious  what 
would  occur  if  this  acid  were  to  come  in 
contact  with  one's  suit  or  other  cloth ;  thus 
it  is  obvious  that  great  care  should  be  ex- 
ercised not  to  permit  it  to  spill. 

With  a  glass  rod  put  a  drop  of  the  liquid 
on  a  quill,  a  feather  or  a  piece  of  white 
silk;  also  place  a  drop  on  the  finger  nail, 
but  wash  it  off  at  once.  Note  any  change 
in  the  color  of  these  substances.  Pour 
into  a  dish  a  few  drops  of  ammonium 
hydroxid  [NH4OH]  and,  using  the  rod,  put 
a  drop  of  this  on  the  places  just  touched 
with  the  acid,  noticing  whether  the  color 
is  intensified  or  reduced. 

Dip  a  splint  and  a  narrow  strip  of  paper 
into  your  liquid,  dry  them,  and  then  set 
them  on  fire,  noting  how  they  burn. 

EXPERIMENT  NO.  84: 

Put  a  few  pieces  of  copper  clippings  into, 
a  dish  and  pour  over  them  some  of  the 
acid  obtained.  [This  is  the  same  experi- 
ment as  No.  28  in  the  January,  1917,  issue 
of  the  Electrical  Experimenter,  page 
666].  In  Experiment  No.  28,  it  was  stated 
that  hydrogen  was  not  liberated  by  the 
inter-action  of  Copper  and  Nitric  Acid,  the 
equation  being : 

3Cu    +    8HNO3  =  3Cu[NOs]a  +  4HaO  -f-  2NO 
Copper        Nitric         Copper  Water  Nitric 

Acid  Nitrat  Oxid 

[Note] 

[Note. — In  Exp.  28  this  was  given  as  Nitrogen 
Monoxide]. 

As  we  did  not  take  up  the  reason  why 
Hydrogen  is  not  liberated  when  Copper 
is  reacted  upon  by  Nitric  acid,  and  this 
paper  deals  with  the  acid,  it  will  not  be 
out  of  place  to  show  why  the  Hydrogen 
is  not  liberated. 

When  moderately  dilute  Nitric  acid 
[density  1.2]  acts  upon  copper,  the  reac- 
tion may  be  exprest  by  the  following  equa- 
tions : 

2HNO3     =     H20     +     2NO      +  30 
Nitric  Acid        Water        Nitric  Oxid  Oxygen 


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30 

Oxygen 


3Cu 
Copper 


3CuO 
Copper  Oxid 


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THE  ELECTRICAL  EXPERIMENTER 


August,  1917 


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3CuO  +  6HN03  =  3Cu[NO:!]3  +  3H2C> 
Copper  Oxid    Nitric  Acid     Copper  Nitrat  Water 

By  cancelling  the  factors  30  and  3CuO, 
representing  substances  formed  in  one  re- 
action and  used  up  in  another,  and  com- 
bining these  three  equations,  the  following 
equation  is  obtained : 

3Cu  +  8HNO:!  =  3CutN03]2-l- 2NO    +  4H20 
Copper        Nitric        Copper        Nitric  Wafer 
Acid  Nitrat  Oxid 

If  concentrated  acid  is  used  in  place  of 
dilute,  Nitrogen  dioxid  is  liberated,  as 
shown  by  the  following  equations : 


2HNO3  = 
Nitric  Acid 


H20  +  2N02  + 
Water    Nitrogen  Peroxid 


O 

Oxygen 


Cu       +       O       =  CuO 
Copper       Oxygen        Copper  Oxid 


CuO  + 
Copper  Oxid 


2HN03 
Nitric 
Acid 


:Cu[N03]2  4-  H..O 
Copper  Water 
Nitrat 


CHEMISTS! 

tJ 


DON'T  BE  HAMPERED 
by  LACK  of  APPARATUS 

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STUDY  CHEMISTRY  WITHOUT  IT. 

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1221  FIRST  ST 


EVANSVILLE,  INDIANA 


Combining  these  into  a  single  equation,  we 
obtain  the  following: 

Cu    +    4HN03  =  Cu[N03]3  +  2H20  +  2N02 
Copper     Nitric  Acid     Copper       Water  Nitrogen 
Nitrat  Peroxid 

Hydrogen  is  not  evolved  at  the  same 
time,  as  in  the  case  with  Sulfuric  Acid  and 
Hydrochloric  Acid,  but  in  its  place  lower 
oxids  of  Nitrogen  and  even  Nitrogen  it- 
self and  Ammonia  are  formed.  The  ex- 
planation frequently  given  of  this  change 
is  that  hydrogen  is  first  produced,  but 
that  it  at  once  acts  on  the  excess  of  Nitric 
Acid  present,  forming  water  and  the  lower 
oxids  of  Nitrogen.  Thus,  the  formation 
of  nitrous  oxid  by  the  action  of  Nitric 
Acid  on  Copper  is  supposed  to  take  place 
in  the  two  following  stages : 

Cu    +    2HNOa     =     Cu[N03]2     +  2H 
Copper      Nitric  Acid      Copper  Nitrat  Hydrogen 


6H 
Hydrogen 


2HNOa 
Nitric  Acid 


2NO  +  4H20 
Nitric  Oxid  Water 


According  to  Veley,  however,  this  ex- 
planation is  not  correct,  inasmuch  as  pure 
Copper,  Mercury  and  Bismuth  do  not  dis- 
solve in  pure  dilute  Nitric  Acid,  but  dis- 
solve readily  when  nitrous  acid  is  present, 
or  by  impurities  in  the  metal  inducing  a 
local  electric  current;  the  first  product  of 
the  Nitric  Acid  is  Nitrous  Acid,  and  the 


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CHICAGO,  ILL. 


Racine  Universal  Motor  Co. 

304  South  Dearborn  Street 


production  of  lower  oxids  of  nitrogen  he 
regards  as  due  to  the  subsequent  changes 
occurring  between  nitrous  acid  and  the 
metallic  nitrat  or  nitrit  in  presence  of  an 
excess  of  Nitric  Acid,  and  nitrous  acid 
being  decomposed  as  fast  as  formed. 
[Proceeding  of  the  Royal  Society,  1890, 
46,  216;  and  others.] 

Upon  the  addition  of  the  acid  to  the 
copper  action  should  commence  at  once, 
forming  a  deep-green  solution,  and  dense 
brown  fumes  of  Nitrogen  Peroxid  liber- 
ated. 

EXPERIMENT  NO.  85: 

Dilute  the  solution  obtained  in  the  pre- 
ceding experiment  and  put  in  a  clean  test 
tube.  Add  a  little  Potassium  Hydroxid 
and  note  results.  A  blue  precipitat  should 
form  of  Copper  Hydroxid  [Cu[OH]2]. 
EXPERIMENT  NO.  86: 

Dilute  some  of  the  acid  obtained  in  Ex- 
periment 84  and  put  in  a  clean  test  tube. 
Add  a  little  Ammonium  Hydroxid  [NH, 
OH].  Upon  the  addition  of  the  Am- 
monium Hydroxid  a  dark  blue  solution  is 
formed  similar  to  the  preceding,  and  with 
a  blue  precipitat. 

Add  an  excess  of  Ammonium  Hydroxid 
and  note  results.     The   precipitat  should 
disolve  upon  the  introduction  of  an  excess 
of  the  Hydroxid. 
EXPERIMENT  NO.  87: 

Dilute  a  little  more  of  the  solution  ob- 
tained in  Experiment  No.  84  and  put  in 
another  clean  test  tube.  Add  a  little  Am- 
monium Hydroxid  and  note  results.  A 
dark  blue  solution  should  form  with  a 
light  blue  precipitat.  Introduce  an  iron 
nail  in  this  solution.  Upon  the  introduc- 
tion of  the  nail  the  copper  should  deposit 
on  the  nail,  action  taking  place,  the  nail 
being  attacked  by  the  solution,  forming  a 
yellow  solution.  Add  an  excess  of  Am- 
monium Hydroxid  and  allow  to  stand  a 
few  minutes.  After  a  few  minutes  a 
brownish  red  precipitat  of  Ferric  Hydrat 
[Fe2[OH]2]  results. 
EXPERIMENT  NO.  88: 

Copperas  Test  for  Nitrat : — Pour  into  a 
tube  5  cc.  of  Sodium  Nitrat  [NaNO,]  or 
other  nitrat  solution  and  the  same  volume, 
both  estimated,  of  Ferrous  Sulfate  [FeSO*] 
solution  freshly  made.  Shake  the  mixture 
well  together.  Then  run  a  thistle  tube  to 
the  bottom  of  the  mixture  and  pour  thru 
it  about  the  same  volume  of  strong  Sulfuric 
acid,  having  the  two  tubes  perfectly  quiet, 
or  use  clamps  [Fig.  79],  till  you  observe 
a  brown  ring  [halo]  at  the  junction  of  the 
two  liquids.  Its  composition  is  uncertain, 
but  it  comes  from  the  action  of  Sulfuric 
acid  on  the  nitrat  to  form  Nitric  Acid, 
which  is  perhaps  reduced  to  Nitrous  Acid 
[HNO.]  by  Ferrous  Sulfate  [FeS04], 
which  thereby  becomes  oxidized  to  [Fe 
SOj]3.  This  experiment  is  sometimes  done 
by  mixing  the  supposed  Nitrat  and  Sul- 
furic acid  then,  when  it  is  cool,  laying  the 
Ferrous  Sulfate  solution  on  the  surface 
with  a  pipette.  The  brown  ring  is  often 
regarded  as  [FeS04]*  [NO]y  [unstable]. 


ATTENTION    WIRELESS  AMATEURS 

We  anticipate  that  very  shortly  all  of  the  amateur  wireless  receiving  stations  will  be  reopened.  Our 
stock  of  wireless  instruments  was  never  more  complete  than  it  is  at  this  time.  We  have  large  quantities 
of  every  item  listed  in  our  big  300  page  catalog  and  in  the  few  cases  where  our  stock  was  low  it  has  been 
replenished.  Our  wireless  business  is  one  out  of  five  big  departments  of  our  business  and  our  patrons  can 
always  rest  assured  of  prompt  service  for  anything  in  the  electrical  or  wireless  line  at  any  time  in  the  future. 

If  you  are  without  our  big  300  page  No.  11  electrical  and  wireless  catalog,  would  suggest  that  you  send 
8  cents  for  it  at  once. 

There  will  be  no  special  sale  on  wireless  instruments  by  this  company  during  the  continuance  of  the  war. 

THE  WILLIAM  B.  DUCK  COMPANY,  230-232  superior  St.,  Toledo,  Ohio 


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August,  1917 


THE  ELECTRICAL  EXPERIMENTER 


287 


9 


h  m   a 

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LP  


WILL  TRADE  my  $11  omnigraph  with  dials 
for  chemicals  and  chemical  apparatus  or  a  6-60 
or  cash.  F.  Mursch,  321  W.  44th  St.,  New  York 
City.  

WONDERFUL  BARGAIN!  $35  receptor,  never 
used,  $25.  Your  opportunity.  Card  brings  par- 
ticulars.     Roland  Place,  Fall  River,  Mass.  

FOR  SALE; — Single  cylinder  Indian  engine  two 
and  a  half  horsepower,  $6.50,  f.  o.  b.  Quincy,  111. 
Ralph  McLaughlin,  1318  N.  4th  St.,  Quincy,  111. 

JUST  THE  THING  for  motorboat^S  horse- 
power Continental  automobile  engine,  clutch  in- 
cluded,  to  trade   for  electric   lighting  plant.  J. 

Flagg,  Sidney,  Neb.  

LOOKEY  HERE!!! 

Brand  New  Thordarson,  Type  "H,"  1  K.W. 
Transformer,  cost  $30,  condenser,  rotary  gap,  large 
X-Ray  Tube  and  Tesla  Coil,  giving  12-inch  spark, 
complete  $35.  Also  all  kinds  of  other  electrical 
goods  for  sale.  Chicago  Experimenters  please 
visit.  No  obligation  to  buy.  Phone  Lakeview 
1045.  Others  write  your  needs.  Have  almost 
anything  and  will  almost  give  it  away.  Ralph 
Weddell,  1050  Buena  Ave.,  Chicago.  

FOR  SALE  OR  EXCHANGE— Aerothrust  twin 
cylinder  3  H.P.  rowboat  engine  with  32-inch  pro- 
peller in  perfect  condition  for  $25,  or  Victor  Pho- 
nograph and  records.  Otto  C.  Rolli,  426  Dewalt 
Ave.,  S.  W.,  Canton,  Ohio.  

FOR  SALE — New  Columbia  Bike;  Omnigraph; 
Audio  Tron  panel  complete;  Brandes  phones,  2,000 
ohms;  Blitzen  Electrolytic  Interrupter;  Variables; 
Receiving  Condenser;  Receiving  Transformer; 
Willard  6-60  Storage  Battery.  Everything  cheap, 
write  for  prices.     Geo.  Auten,  Oberlin,  Ohio. 

FOR  SALE — Electric  Therapeutic  Apparatus 
Machine  Second-hand  in  good  condition,  used  by 
physicians  for  rheumatism  and  circulation.  Will 
sell  at  a  very  reasonable  price.  John  Ferguson, 
113  West  63d  St.,  New  York  City;  home,  364 
West  57th  St.  

WANTED — Two-inch  spark  coil,  high  tension 
condenser  and  zinc  spark  gap.  Send  description. 
J.  Ray  Smith,  McConnelsville,  Ohio.  R.  F.  D. 
No.  3.  

FOR  SALE— 1913,  5  H.P.  Harley-Davidson 
Motorcycle  in  perfect  condition  all  the  way  round. 
Write  C.  H.  Calhoun,  Madison,  Fla. 

EXCHANGE— Meccano  Set  No.  4  for  motor 
cycle  engine.  Stuart  Cope,  Highland,  Middletown, 
Conn.     R.  R.  No.  1. 

FOR  SALE— One  Steffey  Motor  Bicycle  in  good 
running  order,  $15.  One  Charging  Dynamo,  $15. 
Write,  Russell  Moir,  Kent,  Minn. 

FOR  SALE— $4  Loading  Coil.  $2;  $25  Audion, 
$10;  $5  Film  tank  3'A  x  S'A,  $2;  $3  Boxing 
Gloves,  $1.50;  New  $65  Visible  Typewriter,  $10. 
Raymond  Schlegel,  East  Liberty,  P.  O.  Box  329, 
Pittsburgh,  Pa. 

ODDS  AND  ENDS— New  and  shopworn— 3 
H.P.  gas  engine  with  new  dynamo  and  carbu- 
retor, $17.  Complete  set  of  castings  for  Wheeler 
6-inch  machine  shop  bench  lathe,  $7.  Wood  turn- 
ing tools.  }/&  H.P.  steam  engine,  %  H.P.  A.C. 
motor,  copper  plating  outfit,  K.W.  transformer 
coil,  loose  couplers  and  audions.  Louis  E.  Schwab, 
3708  Brooklyn  Ave.,  Cleveland. 

FOR  SALE— 1-inch  coil  panel  set,  $6;  10,000 
meter  Navy  Type  Loose  Coupler,  $8;  4,000  Meter 
Arlington  Navy  Type  Loose  Coupler,  $7;  Crystaloi, 
$1.50;  500  ft.  No.  14  Copper  Wire,  $1.50;  7  Ball 
Insulators,  $1 ;  Commercial  Type  Oscillation 
Transformer,  $7.  Everything  guaranteed.  Leroy 
Bremmer,  care  of  Laufersweiler  Furniture  Co., 
Fort  Dodge,  Iowa. 

WANTED — Old  Edison  moving  picture  machine 
or  mechanism,  used  camera  and  typewriter.  M. 
Miller,   La  Harpe,  Kans. 

MY  $200  Electrical  Laboratory  must  be  sold 
as  I  am  to  leave  for  college.  Have  apparatus 
pertaining  to  wire  and  wireless  telegraphy,  physics 
and  electrochemistry.  Send  for  price  list.  Mark 
Slabodnik,  Box  91,  Ely,  Minn. 


FOR  SALE— Silicon  Detector  without  cat 
whisker  wire,  50c;  1,000  ohm  Receiver,  75c; 
Galvanometer.  25c;  Telegraph  Set,  50c;  Leather- 
covered  headband,  50c.  Remittances  must  accom- 
pany order.  Write  Harry  Layman,  Davidsville, 
Pa. 


UKULELE— Koa  wood,  $10,  or  trade  for 
camera.  Give  size,  lens,  style,  make,  etc.,  or 
guitar.    Clyde  B.  Marx,  Kaskela,  Oregon. 


FOR  SALE — Otis  Clapp  Static  Machine  in  first- 
class  condition.  Two  19"  plates  on  hand  operated 
end.  Ten  29"  plates  on  power  operated  end. 
Several  Leyden  jars  and  various  discharging  de- 
vices to  go  with  machine.  Cabinet  measures 
66"x66"x30  wide.  All  enclosed  in  glass,  $75, 
f.o.b  Mattapan,  Mass.  Cost  $450.  Fritz  Henrici, 
Mattapan,  Mass. 


WANTED — Wireless  transformer,  state  size, 
make,  condition  and  price.  My  1-inch  coil  goes 
for  $3.    J.  R.  Dean,  Rochester,  N.  Y. 


|llllllllll!lll!lll[l!lll!llllllll![lllll!lll!lll 

|    TALK  ABOUT  RESULTS !  | 

17  PRYER  LANE, 
Larchmont  Manor,  N.  Y.  jj 

■  The  Experimenter  Pub.  Co. 

New  York  City 

[  Dear  Sir: — 

Talk  about  results!  You've  1 

1  got  to  give  it  to  the  "E.  E."  |j 

B  to  reach  the  right  people.  On  ■ 

m  the  day  after  "E.  E."  came  | 

I  out  I  received  a  reply  and  ■ 

m  they  have  been  coming  in  at  ■ 

I  the  rate  of  one  a  day.   If  I  | 

■  ever  have  anything  else  that  | 

■  I  want  to  sell  I  will  send  my  §§ 

■  "ad"  to  you  every  time. 

Yours  truly, 
Clarence  de  Witt  Rogers,  Jr.  j 

Iiiiiiiiia 


BARGAINS — Leaving  home,  must  sell.  New 
Electron  Relay,  $3;  slightly  used,  $2.  Loose  Coup- 
ler, $1.  500  volt  D.  C.  1/3  horsepower  Holtzer 
Cabot  motor  and  rheostat  equal  to  new,  $15. 
D.  P.  1,000  ohm  phone,  headband,  cord,  $1.25. 
Electrolytic  detector,  75c.  Telephone  magnetos, 
solid  armature,  50c,  laminated,  $1.  $10  Remy  6 
volt  automobile  magneto,  good  condition,  $3.  Six- 
inch  parabolic  reflector,  50c;  new  bulbs,  20c. 
High  resistance  ringer  coils,  15c  each;  telephone 
transmitters,  50c;  receivers,  50c;  induction  coils, 
20c;  y2  lb.  22  German  Silver  wire,  35c;  2  lb. 
antenium  wire;  40c;  quantity  2  strand  steel  guy 
wire  cheap.  Premo  Junior  No.  2  Camero,  new, 
$1.  Mechanical,  electrical  magazines  cheap.  Pre- 
paid except  magnetos,  motor,  wire.  Stamps  or 
money  order,  or  write  for  further  information. 
Kenneth  Bard,  Manawa,  Wis. 


EXCHANGE — Complete  set  of  parts  for  a  Ford 
engine,  with  exception  of  crank  shaft  and  flywheel 
for  a  panel  type  receiving  set,  typewriter  or  wire- 
less supplies.  J.  Yates  Van  Antwerp,  35  South 
Perry  St.,  Johnstown,  N.  Y. 

SALE  OR  EXCHANGE— B-Flat  cornet,  $12; 
shotgun,  $3;  incubator,  $3.  John  Enos,  Wellfleet, 
Mass. 


FOR  SALE— 1H  H.P.  Gas  Engine,  500  watt  110 
volt  D.C.  Generator,  small  lathe,  %  H.P.  110 
volt  D.C.  motor,  Jeweler's  Foot  Wheel.  Write 
for  description.  J.  H.  Clemmer,  Blue  Creek,  W. 
Va. 


FOR  SALE— Motor,  $10;  Headset,  $4;  1-inch 
Coil,  $3;  a  Potentiometer,  $3;  Detector,  $2;  Spark 
Gap,  $1 ;  Sending  Condenser,  $2.  Paulding,  Can- 
terbury School,  New  Milford,  Conn. 

FOR  SALE — Alternating  Current  Electric 
Sewing  Machine  Motor,  $15;  new  condition;  cost 
$30.  H.  N.  Richmond,  1628  Washington  Ave., 
Colorado  Springs,  Colo. 

WANTED — Second-hand  generator  suitable  for 
charging  storage  batteries.  Must  be  in  first-class 
condition.    Archie  E.  Banks,  Delmar,  Va. 

FOR  SALE — 5,000  mile  Audion  Receiving  Set, 
complete,  $40.  George  Leonard,  11  Hamlet  St., 
Uphams  Corner,  Mass. 


NEW  $8.50  (4x5)  Kodak  $5.50;  $35  1/6  K.W. 
Dynamo  $20.  Want  yi-K.W.  Generator.  Edwin 
Puis,  Hoskins,  Nebr. 


VEST-POCKET  AUTOGRAPHIC  KODAK 
wanted.  Cash  paid  or  swap  even  for  unused 
new  Colby  Tuner  with  switches.  Brainerd  Strat- 
ton,  Oneida,  N.  Y. 

FOR  SALE — Eighteen-foot  speed  boat  hull, 
double  rudders.  Never  in  water,  $30.  Howard 
Tbuemmel,  53  Park  Ave.,  Guttenberg,  N.  J. 

BARGAINS — Jeweler's  Elgin  Lathe  for  $10. 
Write  for  description.  Wireless  Apparatus  for 
sale,  send  for  list.  Clarence  Gunderson,  Albert 
Lea,  Minn. 


SWAP — Cabinet  receiving  set.  Moving  Picture 
Machine.  No  Toy.  Want  Blitzen  or  Type  D 
Tuner.  Variables,  Perikon  and  25  Automatic. 
Carl  Cardin,  Cushing,  Okla. 

WANTED — Used  Motorcycle  at  a  bargain. 
Those  having  one  for  sale,  please  write  to  Claude 
Gallaher,  R.  No.  3.     Vebler,  So.  Dak. 

FOR  SALE — Mechanic's  11 -inch  Lathe,  $35~; 
$40  Racycle,  $15;  Chemicals  and  laboratory  appa- 
ratus.    M.  F.  Flavian,  Munhall,  Pa. 

FIXED  RECEIVING  CONDENSER  $1.  C. 
Phelps  Dodge,  Jr.,  Haystack  Gulch,  Brookvale, 
Colo. 


VIBROPLEX,  Two  sounding  relays  250  and 
150  ohms;  relay  50  ohms;  sounder  4  ohms;  Brandes 
phones,  all  $20.  Graflex  Camera,  3  A,  F.6.3,  $65, 
or  exchange  equal  value.  W.  F.  Dolezal,  342 
East  80th  St.,  N.  Y.  C. 

FOR  SALE — 3  No.  366  Murdock  variable  con- 
densers, $3  each;  1  No.  368  Murdock  variable 
condenser,  $2.25;  1  No.  364  Murdock  variable 
condenser,  $2.25;  1  Monotone  quenched  gap, 
75c;  1  E.  I.  Co.  1  K.W.  condenser,  $3.50;  2 
Electro  rheostat  regulators,  50c.  each;  2  Electro 
fixed  variable  condensers,  75c.  each;  1  lb.  No.  32 
S.  S.  C.  magnet  wire,  $2;  3  lb.  No.  22  S.  S.  C. 
wire,  $3;  1  lb  No.  24  S.  S.  C  wire,  $1;  1  Electro 
rotary  potentiometer,  $1.25;  2  complete  audion 
high  voltage  potentiometers,  75c.  each.  Every- 
thing is  in  good  condition.  Transportation  extra. 
Edw.  C.  Schurch,  Deer  Lodge,  Mont. 

SELL — 8-volt  10  ampere  Dynamo,  $8;  Type 
S.  S.  Dynamo,  $3.50;  Spark  Coil  ^-inch,  $1; 
Ignition  Magneto,  $3;  6-Volt  60  ampere  hour 
storage  battery,  $7.  All  for  $20.  Write  for  par- 
ticulars. J.  R.  Wilkinson,  Las  Cruces,  New 
Mexico. 


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288 


THE  ELECTRICAL  EXPERIMENTER 


August,  1917 


Opportunity  Exchange 


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books  for  $1.50  prepaid.  Regular  selling  price 
of  these  four  books  is  $2.75.  We  guarantee  you 
will   be   satisfied.     Experimenter   Publishing  Co., 

Inc.,  233  Fulton  St.,  New  York  City.  

"  OLD  E.E.  BACK  NUMBERS — We  have  some 
valuable  old  E.E.  back  numbers  on  hand  as  per 
list  below:  . 

X9i 5.  March    .  .price  each  $.20 

Jan.    ...  .price  each  $.25      April    ...  " 

Feb   "      "  May  •  •  •  •  „ 

March  ....  "  June  

April  ....    "      "  J«]y   

May   August  .. 

June    "      "       "  Sept  

juiy      -  -  ::   get       i(  M 

August  ...    "  Nov  

Sept   "      "      "  Dec  

Oct   "      -      -  1917-        „  „ 

Nov  Jan   „  •}.? 

Dec   "      "      "       Feb.  ....   

March  .... 

1916.  April    ...  " 

Jan   "      "    -20  May   

Feb   "      "  . 

We  can  fill  orders  at  once  upon  receipt  of  your 
remittance  and  if  ycu  have  not  these  numbers  al- 
ready now  is  your  chance  to  get  them  as  they 
probably  will  be  snapped  up  very  quickly.  Ex- 
perimenter Publishing  Co.,  233  Fulton  St.,  New 
York  City.   


BUSINESS  OPPORTUNITIES 


FREE  FOR  SIX  MONTHS— My  special  offer 
to  introduce  my  magazine,  "Investing  for  Profit." 
It  is  worth  $10  a  copy  to  any  one  who  has  not 
acquired  sufficient  money  to  provide  necessities 
and  comforts  for  self  and  loved  ones.  It  shows 
how  to  become  richer  quickly  and  honestly.  "In- 
vesting for  Profit"  is  the  only  progressive  financial 
journal  and  has  the  largest  circulation  in  America. 
It  shows  how  $100  grows  to  $2,200;  write  now 
and  I'll  send  it  six  months  free.  H.  L.  Barber, 
613-20  W.  Tackson  Boulevard,  Chicago. 


Gentlemen:  B 

When  it  comes  to  results  the  "E.E."  |j 

is  all  broke  out  with  it.    Reed  an  jj 

answer  with  the  same  mail  that  I  got  g 

the  magazine  on.  S_ 

Yours  truly,  S 

Bernard  Brown.  g 


CHEMICALS 


CHEMICAL  LABORATORY  FOR  $5  contain 
ing  44  expensive  chemicals  as  Iodine,  Mercury 
etc.  Wash  bottle  complete,  flask,  test  tubes 
holder,  funnel,  graduate,  tubing,  filter  paper,  etc 
Description  and  catalog  of  chemicals  and  appa 
ratus  for  stamp.  Zenith  Chemical  Laboratories, 
Duluth,  Minn.  

EXPERIMENTERS— Are  you  interested  in 
novel  chemical  experiments?  Send  10c.  for  large 
collection.  Merel  Sager,  44  Apple  St.,  Tiffin, 
Ohio. 

HELP  WANTED 

THOUSANDS  MEN-WOMEN,  18  or  over, 
WANTED  for  U.  S.  Government  Jobs.  $75  to 
$150  month.  War  means  many  vacancies.  Steady 
work,  short  hours.  Rapid  advancement.  Com- 
mon education  sufficient.  Write  immediately  for 
list  of  positions  now  obtainable.  Franklin  Insti- 
tute, Dept.  E27,  Rochester,  N.  Y.  

MISCELLANEOUS  

ELECTRICIANS— Send  50c.  for  10  Blue  Prints 
of  Motor  and  Generator  connections.  28  for  $1. 
10  A.C.,  4  D.C.  Motor  Winding  diagrams  for  $1. 
20  A.C.,  6  D.C.  and  6  Rotary  Converter  Draw- 
ings, $1.60.  32  A.C.,  6  D.C.  and  6  Converter 
drawings,  $2.25.  Winding  made  easy.  Superior 
Electric  Co.,  Superior,  Wyo. 


Hill! 


151  LAKE  AVE.,  jj 

Lancaster,  N.  Y.  jj 

jj  Gentlemen:  g 

B     /  wish  to  tell  you  that  my  ad.  in  g 

g  the  E.  E.  was  a  great  success,  and  JJ 

|§  exceeded  all  expectations.    I  had  re-  |j 

a  plies  before  I  had  received  a  copy  of  jj 

j§  the  issue  myself.  This  goes  to  show  m 

H  that  every  issue  is  looked  for  with  g 

S  great  interest,  and  the  wide  field  your  g 

g  paper  covers.   I  certainly  will  recom-  g 
S  mend  it  to  the  amateurs  that  have 
\     something  to  trade  or  sell. 
=               Yours  respectfully, 

i  G.  W.  Bradford.  ■ 


m\ 


BE  POPULAR — Amuse  your  friends  wherever 
you  go  with  my  six  baffling  puzzles  and  tricks. 
Complete  set  for  10c.  Address,  H.  J.  Kunow, 
2246  N.  Tripp  Ave.,  Chicago,  111. 

TEN  POST  CARDS  "Beautiful  Women"  Cor- 
respondence  Exchange  membership  three  months. 
How  to  obtain  best  premiums  free.  Send  three 
dimes  in  envelope.    Burg.  Commercial,  Gary,  Ind. 

ENORMOUS  PROFITS  monograming  automo- 
biles,  motorcycles,  trunks,  etc.,  with  our  trans- 
fer initials.  Wholesale  price  list  and  samples 
free.     Globe    Decalcomanie    Co.,    Mfrs.,  Jersey 

City,  N.  J.  

_  STAMPS— 75,  all  different,  free.  Postage,  2c. 
Mention  paper.    Quaker  Stamp  Co.,  Toledo,  Ohio. 

BARGAIN — Green  silk  telephone  cords,  3  feet, 
receiver  cords,  10c;  8  ft.  lengths,  3  strands,  35c; 
22  ft.  lengths,  75c.  Wm.  Horlick,  186  Belmont 
St.,  Maiden,  Mass.  

WORN  OUT  DRY  BATTERIES  CAN  BE  RE- 
CHARGED for  less  than  one  cent.  Send  twenty 
cents  for  formula  to  E.  Bohner,  1009  South 
Wabash,  Chicago.  

100  GOOD  Quality  Business  Envelopes  printed, 
50c.  Envelope  Printing  Dept.,  Box  382,  Marshall- 
town,  Iowa.  

WE  HAVE  a  limited  number  of  beautiful  art 
pictures  of  the  following  famous  electrical  men  on 
hand.  Nikola  Tesla,  Thomas  A.  Edison,  Guglielmo 
Marconi,  Charles  P.  Steinmetz  and  Reginald  A. 
Fessenden.  These  make  a  handsome  decoration 
for  any  laboratory  or  workshop  and  should  be 
prominentlv  displayed.  Price  for  five,  prepaid, 
25c.  Experimenter  Pub.  Co.,  233  Fulton  St.,  New 
York  City. 

PATENT  ATTORNEYS 

PATENTS— R.  Morgan  Elliott  &  Co.,  Patent 
Attorneys,  Mechanical,  Electrical  and  Chemical 
Experts,  716-724  Woodward  Bldg.,  Washington, 
D.  C.  

PATENTS — Without  advance  attorney's  fees. 
Not  due  until  patent  allowed.  Send  sketch  for 
free  report.  Books  free.  Frank  Fuller,  Wash- 
ington.  D.  C.  

PATENTS  ON  EASY  PAYMENTS— Send 
model  or  sketch  for  Free  Search  and  Certified 
Registration  of  Your  Invention  for  Your  Protec- 
tion. Free  Book  Tells  What  to  Invent  and  How 
to  Obtain  a  Patent  on  Easy  Payments.  C.  C. 
Hines  &  Co.,  593  Loan  &  Trust  Bldg.,  Washing- 
ton,  D.  C.  

IDEAS  WANTED — Manufacturers  are  writing 
for  patents  procured  through  me.  Four  books 
with  list  hundreds  of  inventions  wanted  sent  free. 
I  help  you  market  your  invention.  Advice  Free. 
R.  B.  Owen,  130  Owen  Bldg.,  Washington,  D.  C. 

JOHN  M.  McLACHLEN,  attorney  -  at  -  law, 
Patent  causes.     Union  Trust  Bldg.,  Washington, 

D.  C. 

 PHONOGRAPHS  

BUILD  YOUR  OWN  PHONOGRAPH  or  manu- 
facture them  for  profit.  Drawings,  instructions, 
etc,  Twenty-five  Cents.  Satisfaction  guaranteed. 
Circular  free.    Associated  Phonograph  Co.,  Dept. 

E,  Cincinnati. 

WIRELESS  

SPECIAL!!  While  stock  lasts — brand  new  un- 
used genuine  Lenzite  Detectors  prepaid — $3.75. 
Brainerd  Stratton,  Oneida,  N.  Y. 

FIRE  SALE — We  have  a  great  many  slightly 
damaged  electrical  apparatus  and  supplies  on  hand 
which  we  are  selling  at  extraordinarily  low  prices 
while  they  last.  These  goods  were  damaged  in 
our  recent  fire  and  embrace  such  goods  as  tele- 
phone receivers,  telephone  cords,  printing  presses, 
telimphones,  detectors,  tuning  coils,  rotary  con- 
densers, leyden  jars,  porcelain  tube  insulators, 
strap  keys,  Gernsback  relays,  Inter-City  transmit- 
ting outfits,  etc.,  etc.  Send  for  list  and  prices  to- 
day. Wonderful  bargains  such  as  will  not  readily 
occur  again  for  a  long  time  to  come.  Electro 
Importing  Co.,  231  Fulton  St.,  New  York  City. 


ucceei 


This  interesting  story 
shows  you  the  way  to 
greater  success  in  the 
Electrical  Field. 


**  For  the  man  not  getting:  a 
college  training;  and  even  in 
that  case.  I  can  sincerely  s^ay  I 
do  not  believe  there  is  a  better 
set  of  books  in  the  market  to- 
day." Lloyd  D.  Huffman 
Dayton,  O. 

11  We  consider  Hawkins  Elec- 
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and  complete  set  of  electrical 
references  in  the  market." 
Nogglb  Electric  Works 
Monterey,  Cal. 
"Hawkins  surely  khowb  the 
art  of  condensing  informa- 
tion/'      Elbridge  F.  Ball 
Buckland,  Conn. 


This  is  the  Electrical  age. 
Electricity  now  controls  more 
trades,  directs  more  men,  offers 
more  opportunities  than  any 
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eay  there  are  no  better  electrical  books  published  at  any  price. 

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10  NUMBERS  IN  ALL 


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Send  no  money.    Examine  the  books  first.    Decide  for  yourself  that  they 
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A  PEW  OF  THE  SUBJECTS 

Magnetism — Induction — Experiments  —  Dynamos 
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of  Dynamos  and  Motors — Distribution  Systems — 
Wiring— Wiring  Diagrams— Sign  Flashers— Stor- 
age Batteries— Principles  of  Alternating  Currents 
and  Alternators— Alternating  Current  Motors- 
Transformers— Converters— Rectifiers— Alternat- 
ing Current  Systems— Circuit  Breakers— Measur- 
ing Instruments — Switch  Boards— Wiring— Power 
Stations  —  Installing  — Telephone —Telegraph — 
Wireless— Rells— Lighting— Railways.  Also  many 
Modern  Practical  Applications  of  Electricity  and 
Beady  Reference  Index  of  the  10  numbers. 


we  are  offering.   See  the  books  first, 
then  decide.   If  you  decide  to  keep 
them  you  can  make  settlement  at 
only  $1.00  monthly  until  paid  for. 


Theo.  Audel  &  Co. 
72  Fifth  Ave.,  N.  Y. 

Please  send  me  for 
FREE  examination 
Hawkins  Electrical 
Guides  (Price  $1.00  each). 
Ship   at   once   prepaid  the 
TEN  numbers.  If  satisfactory 
I  agree  to  send  you  $1.00  each 
month  until  paid. 


Signature 


Theo.Audel&Co.^ 


Occupation. 


72  Fifth  Ave. 
NEW  YORK 


Business  Address. 


Residence 


Reference 


Aug.  E.E. 


You  benefit  by  mentioning  "The  Electrical  Experimenter"  when  writing  to  advertisers. 


This  is  a  War  of 
Brains 

THE  men  behind  the  firing  lines  win 
the  modern  battles  as  much  as  the 
men   in   the   trenches.     One  can't 
succeed  without  the  aid  of  the  other. 

When  your  call  comes,  do  you  go  into 
the  trenches  or  are  your  services  so  valu- 
able that  you  are  directed  to  do  work 
in  the  rear  which  the  army  staff  consid- 
ers more  important?  THINK  IT  OVER. 

"The  Nation  needs  each  man  in  the  en- 
deavor that  will  best  serve  the  common 
good.  The  Nation  is  being  served  only 
when  the  sharpshooter  marches,  and 
the  machinist  remains  at  his  levers,"  said 
President  Wilson  in  his  proclamation  of 
May  17th. 

Are  You  Qualified? 

Can  you  do  things?  Could  you  repair 
a  burnt  out  armature  in  the  field?  Could 
you  re-wire  a  switchboard  damaged  by 
shot?  Could  you  ACTUALLY  DO  a 
thousand  and  one  things  of  an  electrical 
nature  in  case  of  emergency  at  the  front? 
You  may  now  have  a  good  electrical 
knowledge  acquired  bv  reading  books 
and  magazines,  BUT  YOU  CAN'T  DO 
the  things  you've  read  about,  at  least  not 
EFFICIENTLY  and  METHODI- 
CALLY. Some  one  will  be  called  to  the 
spot  to  do  the  work.  That  chap  HAS 
EXPERIENCE,  which  you  lack. 

Learn  by  Doing 

the  same  as  he  did,  and  you  will  not 
have  occasion  to  regret  it  when  it  is  too 
late. 

The  crying  need  of  America  today  is 
Men  who  are  trained  to  do  things,  not 
dabblers,  but  PRACTICAL  men— men 
who  can  take  a  situation  in  at  a  glance, 
due  to  their  EXPERIENCE. 

Only  One  Way  to  Learn 
Electricity 

The  only  way  you  can  become  an  ex- 
pert is  by  doing  the  very  work  under 
competent  instructors,  which  you  will  be 
called  upon  to  do  later  on.  In  other 
words,  learn  by  doing.  That  is  the 
method  of  the  New  York  Electrical 
School. 

Our  concentrated  work  with  actual  appara- 
tus under  actual  conditions  will  put  you  abreast 
of  men  with  from  5  to  10  years'  experience  in 
the  electrical  field.  4,500  of  our  students  have 
gone  forth  into  electrical  success. 

LEARN  BY  DOING.  This  method  makes 
you  an  expert,  able  to  command  an  expert,  able 
to  command  a  high  salary.  All  instruction  is 
individual.  You  go  ahead  as  fast  as  you  can 
learn.  Good  students  complete  the  course  in 
seven  months.  Send  today  for  FREE  64-page 
book. 

Use  the  handy  coupon  below  and  send  it  to- 
day.   You  will  never  regret  it. 

School  open  to  visitors  from  9  A.  M.  to  9  P.  M. 


New  York  Electrical  School, 

29  W.  17th  St.,  New  York,  N.  Y. 

Please  send  FREE  and  without  obligation  to  me  your  64-page 
book. 


Name 


Address. 


I 
I 
I 


NEW  YORK  ELECTRICAL  SCHOOL 
29  WEST  l7ti!ST., 

NEW  YORK,  N.  Y. 


(f  SEPTEMBER,  1917 


15  CENTS 


POPULAR  •   ELECTRICAL    NEWS  ILLUSTRATED 


ELECTRIC  BLOODHOUNDS 

FIND  AND  DESTROY  SUBMARINES 


SEE  PAGE  298 


LARGEST  CIRCULATION  OF  ANY  ELECTRICAL  PUBLICATION 


This  Is  the  Electrical  Age,  and  this  wonderful  new  profession  is  calling  you.  The 
demand  for  expert  Electricians  is  greater  every  year  and  the  salaries  higher.  Elec- 
tricity is  truly  the  greatest  motive  power  in  the  world,  to-day,  and  now  is  the  time  to 
enter  this  profession. 


YOU  CAN  DO  THIS 


AFTER  HOME  STUDY 

$3622  TO  $10022  A  WEEK 


You  can  earn  $36  to  $100  a  week  and  more  as  an  Expert  Electrician.  If  you  have  a 
common  school  education  I  can  train  you  in  a  few  months  at  home.  Big  lighting  and 
power  companies,  municipalities,  and  manufacturers  are  always  seeking  trained  men  to 
handle  their  Electrical  problems. 

I  Guarantee  Satisfaction 

Every  student  receives  our  Sealed  Guarantee  Bond,  which  guarantees  to  return  every  penny  of  his 
money  if  he  is  not  entirely  satisfied.  No  other  school  has  made  this  wonderful  offer,  but  I  know  the 
success  I  have  brought  to  hundreds  of  my  students,  and  I  know  what  I  can  do  for  any  ambitious  young 
man  who  will  give  me  a  little  of  his  spare  time  each  day. 

FREE  ELECTRICAL  OUTFIT 

Fot   the  next  30   days  I  am   giving  each   student  an   Outfit  of 

™ ™ *                                  ™ ~"  " ™  ~*  ~ ~~  ™~  "**  Electrical    Testing    Instruments,    Tools,    Electrical    materials,  and 

|Ot  £jk  1  I              H  1  ^5              ^^tt  I  I  P          fVl        I  Motor  absolutely  Free.     M>    instruction  is  by  practical  methods  and 

■                  mm      I    ■  ■  m  mW             ^m*                                     .  this  outfit  is  used  in  working  out  the  lessons.     Practical  training 

~~               "~  "~ "  —  ~~  "~ ~  ~—  — ■  ~ ~"  ~~  —  — I  with  the  theory  makes  perfect.    I  am  Chief  Engineer  of  the  Chicago 

Dept.  40,                                                                                                  I  Engineering  Works,  and  I  can  give  you  the  training  that  will  land 

CHIEF  ENGINEER.  Chicago  Engineering  Works,                                 I  the  biS  jobs  and  hold  them. 

439  Cass  St.,  Chicago.   Illinois.                                                        I  „Jf  -vou  ar,e        reaI  earnest  I  want  to  send  you  my  new  Book— 

I  How    to    Become   an   Electrical    Expert.       It  s   free.     No  matter 

Without  obligation  on  my  part  kindly  send  at  once,  fully  prepaid,       |  how  many  other  schools  you  write  to  I  want  you  to  have  my  book 

particulars  of  your  complete  Practical  Home  Study  Course  in  Elec-      I  — It's  different  because  it's  practical — Write  today. 

trlclty  I  CHIEF  ENGINEER  COOKE 

Name    I    CHICAGO  ENGINEERING  WORKS 

Dept.  40      ::       439  CASS  STREET,  CHICAGO,  ILL. 

Address   

T»wn    State  


You  benefit  by  mentioning  "The  Electrical  Experimenter"  when  writing  to  advertisers. 


September,  1917 


THE  ELECTRICAL  EXPERIMENTER 


289 


SOONER  or  later  you  will  be  standing  in  front  of 
the  mahogany  desk.    The  big  man  reclining  in  his 
office  chair  will  gaze  earnestly  at  you  while  his  keen 
gray  eyes  "take  you  in." 

When  this  big  moment  comes,  can  you  make  good? 
Will  you  "come  through"?  Will  you  be  just  another 
one  of  the  million  "little  fish"  trying  hard  to  land  a 
small  job  at  $15.00  a  week,  or  will  you  be  one  of  the  men 
that  DO  things,  at  a  salary  running  into  four  figures? 

Suppose  the  man  behind  the  desk  bombards  you  with 
questions,  such  as  these  :  "Can  you  wire  a  stvitchboard? 
Can  you  lay  out  a  500  light  power  installation  on  the 
drafting  board?  Can  you  rewind  a  10  H.  P.  Direct 
Current  dynamo  armature?  Can  you  plan  and  install 
a  private  telephone  installation  and  75  phones  in  a  new 
factory?" 

Will  you  withstand  such  a  bombardment? 
No,  Sir.   Not  if  you  have  no  actual  experience 
of  you? 

WHAT'S  BACK  OF  YOU?  Just  a  little 
dabbling  in  your  attic  at  home,  a  few  books  ; 
magazines?  Or  have  you  actually  done  thes 
yourself  with  your  own  hands,  in  a  place  wherl 
things  are  done  every  day  ?  The  keen  eyed  man  be 
the  desk  will  know  in  less  than  a  minute.  You  cannot 
bluff  him.  HE  knows.  He  wants  an  expert,  not  a 
dabbler.  It's  experience  that  counts  today.  It's  ex- 
perience that  brings  the  big  coin. 

Learn  by  Doing 

The   only  way  you   can  become  an  expert  is  by  doing  the 
very  work  under  competent  instructors,  which  you  will  be  called 
upon  to  do  later  on.     In  other  words,  learn  by  doing. 
That  is  the  method  of  the  New  York  Electrical  School. 

Our  concentrated  work  with  actual  apparatus  under 
actual  conditions  will  put  you  abreast  of  men  with 
from  5  to  10  years'  experience  in  the  electrical  field. 
4,500  of  our  students  have  gone  forth  into  electrical 
success. 

LEARN  BY  DOING.  This  method  makes  you  an 
expert,  able  to  command  a  high  salary.  All  instruc- 
tion is  individual.  You  go  ahead  as  fast  as  yo-u  can 
learn.  Good  students  complete  the  course  in  seven 
months.     Send  today  for  FREE  64-page  book. 

Use  the  handy  coupon  below  and   send  it 
You  will  never  regret  it. 

School  open  to 


today 


isitors 

from  9  A.  M.  to  9  P.  M. 


Yes,   Sir,   It's  Experts 
We  Want  -  -  -  When 
Can  You  Start?" 


NEW  YORK 

ELECTRICAL  SCHOOL 

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THE  ELECTRICAL  EXPERIMENTER 


September,  1917 


FELDMAN'S  "GEYSER"  ELECTRIC  WATER  HEATER 


Continuous  Flow  of  Water 
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You  only  pay  for  electricity  as  used. 
All  water  that  passes  through  the 
"Geyser"  is  thoroughly  sterilized. 
The  "Geyser"  is  perfectly  insulated 
and  is  absolutely  safe,  no  danger  of 
short  circuiting  or  electric  shock. 

Cold  to  Hot  Water  by  Merely 
Turning  Handle. 

Both  the  water  and  the  current  act 
together  and  both  are  controlled  by 
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To  secure  hot  water  turn  handle  to 
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right,  at  the  center  both  the  water 
and  current  are  shut  off. 

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Vol.  V     Whole  No.  53 


SEPTEMBER,  1917 


No.  5 


ELECTRIC   "BLOODHOUNDS"   TO   FIND  AND   DESTROY  U- 

BOATS   Front  Cover 

From  a  painting  by  George  Wall 

U.  S.  BLOWS  UP  TESLA  RADIO  TOWER   293 

"OUR  NAVY"  ON  THE  STAGE  By  George  Holmes  294 

FOILING  THE  TRAIN  ROBBER  WITH  RADIO   295 

ALL  ABOARD  FOR  "LUNA'S"  ELECTRIC  TOP   296 

TRANSMITTING    SOUND    BY    PHONOGRAPH    AND  TELE- 
PHONE 104  MILES,  THRU  48  PHYSICAL  CHANGES   297 

ELECTRIC   "BLOODHOUNDS"  TO  FIND  AND   DESTROY  U- 

BOATS  By  H.  Gernsback  and  H.  W.  Secor 

"SPY  AERIALS"   

THE  MARVELS  OF  RADIO  ACTIVITY.    PART  II. 

By  Jerome  S.  Marcus,  B.Sc.  (Ch.Er 

LARGEST  ELECTRIC  LOCOMOTIVE  DEVELOPS  7,000  H.P   304 

VOCATION  OF  THE  ENGINEER  By  Prof.  A.  E.  Watson  308 

X-RAY  TUBES  FOR  HIGH  FREQUENCY  COILS. 

By  Dr.  Frederick  Finch  Strong 


298 
300 


302 


309 


310 


THE  FRANKLIN  EXPERIMENTAL  CLUB.  .By  William  J.  Hammer 

EXPERIMENTAL  PHYSICS.    LESSON  7. 

By  John  J.  Furia,  A.B.,  M.A. 

MANUFACTURING   MAGNETISM  By  Rogers  D.   Rusk,  B.Sc. 

A  REMARKABLE  AMATEUR  RADIO  STATION  WITH  A  REC- 
ORD By  A.  F.  Pendleton 

SENATOR    MARCONI    ENCOURAGES    WOMEN'S  WIRELESS 
CLASS 

U.  S.  SIGNAL  CORPS  WANTS  ELECTRICAL'  AND  RADIO  MEN 
THE  PRESENT  STATUS  OF  THE  AUDION.  .By  Dr.  Lee  de  Forest 
"RADIO"-COMMUNICATION  OVER  GAS  AND  WATER  PIPES 

—"WIRED  WIRELESS"    31 

CALCULATION    AND     MEASUREMENT     OF  INDUCTANCE. 

PART  III— CONCLUSION  By  H.  W.  Secor  and  S.  Cohen 

HOW  I  BUILT  A  2^  H.P.  FLIVVER-ETTE  By  Cleage  Feild 

SELENIUM  CELL  DESIGN  AND  CONSTRUCTION. 

By  Thomas  W.  Benson 
MAKING  AN  ELECTRIC  CLOCK  By  Thomas  Reed 


312 
313 

314 

315 
316 
317 


320 
323 


325 
326 


Secret  Intelligence 


N  homme  averti  en  vaut  deux" — a  man 
forewarned  is  worth  two ; — so  runs  the 
well  known  French  proverb. 

To  our  country,  surrounded  by  a  web  of 
spies  and  intrigue,  this  is  of  vital  impor- 
tance today.  Even  when  we  were  at  peace 
with  Germany,  our  officials  soon  learned 
that  the  country  where  the  "art"  of  spying  is  developed 
to  a  higher  degree  than  anywhere  else  on  this  globe, 
stopt  at  nothing  to  secure  important  military  informa- 
tion. When  in  1915  we  ventured  the  opinion  that  the 
Sayville  Radio  station  could  be  and  probably  was  used 
to  send  un-neutral  messages  to  Berlin,  we  were  laughed 
at.  That  same  month  our  Government  took  over  Say- 
ville, after  a  New  Jersey  Radio  amateur  actually  suc- 
ceeded in  "canning"  on  phonograph  cylinders  incriminat- 
ing radio  messages,  sent  out  from  Sayville. 

Today,  being  at  war  with  Germany,  we  are  facing  a 
tremendously  more  difficult  problem  of  dealing  with  the 
spies.  And  evidence  is  not  lacking  that  the  latter  are 
doing  their  work  quite  satisfactorily  to  their  govern- 
ment just  now. 

When  Admiral  Sims  took  his  fleet  to  England,  Berlin 
knew  the  fact  four  days  ahead  of  the  arrival  of  our  ships. 
Again,  when  our  first  transports  were  sent  to  France, 
Berlin  knew  that  too,  days  before  our  ships  reached 
France;  hence,  the  flotilla  of  submarines  lying  in  am- 
bush. 

The  question  is,  how  did  the  enemy  get  the  intelli- 
gence? Our  officials  frankly  admit  that  they  don't  know. 
In  some  quarters  the  opinion  prevails  that  the  informa- 
tion was  sent  by  mail  or  by  wire  to  Mexico — in  clever 
code  of  course — and  thence  sent  across  the  Atlantic  over 
the  powerful  Mexico  City  radio  plant.  This  may  be 
possible,  but  we  much  doubt  it. 

We  can  be  certain  that  a  nation  that  attained  as  high  a 
scientific  development  as  Germany,  will  use  subtler  and 
surer  means  to  convey  priceless  intelligence.  Besides, 
the  round-about  route  thru  Mexico  is  certainly  far  too 
slow  and  too  dangerous,  all  messages  being  closely 
watched  by  our  alert  officials. 

No,  we  must  look  elsewhere.  An  enemy  usually 
attacks  at  the  most  vulnerable  or  exposed  spot.  Un- 
fortunately we  have  thousands  of  such  spots,  namely, 
our  endless  coastlines.  On  the  coast  of  Long  Island 
and  Maine,  for  instance,  there  are  countless  thousands 
of  spots  where  a  human  being  is  hardly  ever  seen. 
There  are  hundreds  of  secluded  little  inlets  and  shel- 
tered spots  from  which  intelligence  could  be  sent  out  in 


a  ridiculously  simple  manner,  and  perfectly  safe  too  for 
the  sender. 

No,  we  don't  think  he  would  be  so  foolish  as  to  oper- 
ate even  a  mediocre  radio  outfit,  for  our  Navy  has  too 
many  ears.  What,  for  instance,  is  to  prevent  a  spy  from 
sending  messages  daily  to  a  submarine  lying  still  some 
ten  or  more  miles  off  the  coast?  This  could  be  accom- 
plisht  by  various  methods.  One  is  by  means  of  the 
Fessenden  underwater  oscillator ;  twenty  to  thirty  miles 
can  be  covered  very  easily.  And  if  we  don't  know  that 
this  sort  of  thing  is  going  on,  we'll  never  discover  the 
spy.  And  we  insist  once  more  that  no  man  in  his  right 
senses  will  use  a  Radio  Outfit — it  is  too  dangerous. 

Then  again  what  is  to  prevent  any  enemy  submarine 
from  bringing  over  an  electric  cable  ten  or  twenty  miles 
long,  unreeling  it  on  a  shallow  sand  bank  (using  a 
motor  boat  to  accomplish  this)  and  establishing  a  secure 
terminal  in  one  of  the  secluded  spots  on  the  coast.  The 
other  end,  twenty  miles  out  in  the  ocean  could  end  in  a 
submerged  buoy.  The  submarine  then  has  nothing  to 
do  but  to  hover  about  that  buoy,  while  the  land  oper- 
ator presses  his  key  at  certain  pre-arranged  hours  of 
the  day.  By  means  of  an  electro-magnet  inside  of  the 
buoy,  the  metal  shell  of  the  latter  is  struck,  spelling  out 
the  Morse  or  other  code  signals.  The  sound  can  be 
muffled  of  course  to  such  an  extent  that  only  a  sub- 
marine with  underwater  microphones  can  hear  the 
sounds  over  a  radius  of  a  few  hundred  feet. 

Then  by  using  its  own  powerful  radio,  the  subma- 
rine can  send  the  message  across  the  Atlantic  either  di- 
rect or  by  relaying  it.  By  radiating  certain  long  un- 
damped waves,  detection  becomes  almost  impossible. 
For  as  soon  as  the  message  is  sent  the  U-boat  submerges 
and  lays  motionless  for  the  next  twenty-four  hours  if 
necessary. 

Now,  this  may  or  may  not  be  the  exact  means  how  the 
trick  is  done,  at  any  rate  we  feel  that  the  intelligence 
leaves  by  way  of  our  coastline — it  is  too  vulnerable  and 
too  inviting. 

The  remedy?  Intensified  and  intelligent  coast  patrols 
— thousands  of  them.  Then  let  us  sink  super-sensitive 
microphones  two  or  three  miles  apart  along  our  entire 
coastline.  This  will  do  two  things :  First,  every  under- 
water signal  could  be  heard,  no  matter  where ;  second, 
hostile  U-boats  could  be  heard  readily  and  accurately 
located. 

We  owe  it  to  our  soldiers  to  take  every  precaution 
humanely  possible.  We  do  not  wish  to  wait  till  a  score 
of  our  transports  have  been  sunk.     H.  Gernsback. 


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293 


THE.  ELECTRICAL 
EXPERIMENTER 


H.  GERM5B&CK  edit* 

H.  W.  5EZUR  4550C1&TE  EDITC7 


Vol.  V.    Whole  No.  53 


September,  1917 


U.  S.  Blows  Up  Tesla  Radio  Tower 


SUSPECTING  that  German  spies  were 
using  the  big  wireless  tower  erected 
at  Shoreham,  L.  I.,  about  twenty 
years  ago  by  Nikola  Tesla,  the  Fed- 
eral Government  ordered  the  tower 
destroyed  and  it  was  recently  demolished 
with  dynamite.  During  the  past  month  sev- 
eral strangers  had  been  seen  lurking  about 
the  place. 

Tesla  erected  the  tower,  which  was  about 
185  feet  high,  with  a  well  about  100  feet 
deep,  for  use  in  experimenting  with  the 
transmission  of  electrical  energy  for  power 

and  lighting  pur-  

poses  by  wireless. 
The  equipment 
cost  nearly  $200,- 
000. 

The  late  J.  P. 
Morgan  backed 
Nikola  Tesla 
with  the  money 
to  build  this  re- 
markable steel 
tower,  that  he 
might  experiment 
in  wireless  even 
before  people 
knew  of  Marconi. 
A  complete  de- 
scription, revised 
by  Dr.  Tesla  him- 
self,  of  this 
unique  and  ultra- 
powerful  radio 
plant  was  given 
in  the  March, 
1916,  issue  of 
The  Electrical 
E  x  p  e  r  i  - 
M  enter.  Every- 
one interested  in  the  study  of  high  frequency 
currents  should  not  fail  to  study  that  dis- 
course as  it  contains  the  theory  of  how  this 
master  electrician  proposed  to  charge  this 
lofty  antenna  with  thousands  of  kilowatts 
of  high  frequency  electrical  energy,  then  to 
radiate  it  thru  the  earth  and  run  ships,  fac- 
tories and  street  cars  with  "wireless  power." 

Most  of  our  readers  have,  no  doubt,  read 
about  the  famous  Tesla  wireless  tower, 
which  structure  involved  the  expenditure  of 
a  vast  sum  of  money  and  engineering  talent. 
From  this  lofty  structure,  which  was  de- 
signed some  20  years  ago  by  Dr.  Tesla  and 
his  associates,  there  was  to  be  propagated 
an  electric  wave  of  such  intensity  that  it 
could  charge  the  earth  to  such  a  potential 
that  the  effect  of  the  wave  or  charge  could 
be  felt  in  the  utmost  confines  of  the 
globe. 

Further,  it  may  be  said  that  Tesla,  all  in 
all,  does  not  believe  in  the  modern  Hertzian 
wave  theory  of  wireless  transmission  at  all. 
Several  other  engineer's  of  note  have  also 


gone  on  record  as  stating  their  belief  to  be 
in  accordance  with  Dr.  Tesla's.  More  won- 
derful still  is  the  fact  that  this  scientist  pro- 


mulgated his  basic  theory  of  earth  current 
transmission  a  great  many  years  ago  in  some 
of  his  patents  and  other  publications.  Brief- 
ly explained,  the  Tesla  theory  is  that  a 
wireless  tower,  such  as  that  here  illustrated 
and  specially  constructed  to  have  a  high 
capacity,  acts  as  a  huge  electric  condenser. 
This  is  charged  by  a  suitable  high  frequency, 
high  voltage  apparatus  and  a  current  is  dis- 
charged into  the  earth  periodically  and  in 
the  form  of  a  high  frequency  alternating 
wave.  The  electric  wave  is  then  supposed 
to  travel  thru  the  earth  along  its  surface 
shell  and  in  turn  to  manifest  its  presence  at 
any  point  where  there  might  be  erected  a 
similar  high  capacity  tower  to  that  above 
described. 

A  simple  analogy  to  this  action  is  the  fol- 
lowing: Take  a  hollow  spherical  chamber 
filled  with  a  liquid,  such  as  water;  and  then, 
at  two  diametrically  opposite  points,  let  us 
place,  respectively,  a  small  piston  pump, 
such  as  a  bicycle  pump,  and  an  indicator, 
such  as  a  pressure  gage.    Now,  if  we  suck 


some  of  the  water  into  the  pump  and  force  it 
back  into  the  ball  by  pushing  on  the  piston 
handle,  this  change  in  pressure  will  be  in- 
dicated on  the  gage 
secured  to  the  op- 
posite side  of  the 
sphere.  In  this 
way  the  Tesla  earth 
currents  are  sup- 
posed to  act. 

The  patents  of 
Dr.  Tesla  are  ba- 
sically quite  differ- 
ent from  those  of 
Marconi  and  others 
in  the  wireless 
telegraphic  field. 
In  the  nature  of 
things  this  would 
be  expected  to  be 
the  case,  as  Tesla 
believes  and  has 
designed  apparatus 
intended  for  the 
transmission  o  f 
large  amounts  of 
electrical  energy, 
while  the  energy 
received  in  the 
transmission  of  in- 
telligence wireless- 
ly  amounts  to  but 
a  few  millionths  of 
an  ampere  in  most 
cases  by  the  time 
the  current  so 
transmitted  has 
been  picked  up  a 
thousand  miles 
away.  In  the  Hert- 
zian wave  system, 
as  it  has  been  explained  and  believed  in,  the 
energy  is  transmitted  with  a  very  large  loss 
to  the  receptor  by  electro-magnetic  waves 
which  pass  out  laterally  from  the  transmit- 
ting wire  into  space.  In  Tesla's  system  the 
energy  radiated  is  not  used,  but  the  current 
is  led  to  earth  and  to  an  elevated  terminal, 
while  the  energy  is  transmitted  by  a  process 
of  conduction.  That  is,  the  earth  receives  a 
large  number  of  powerful  high  frequency 
electric  shocks  every  second,  and  these  act 
the  same  as  the  pump  piston  in  the  analogy. 

Quoting  from  one  of  Tesla's  early  pat- 
ents on  this  point :  "It  is  to  be  noted  that 
the  phenomenon  here  involved  in  the  trans- 
mission of  electrical  energy  is  one  of  true 
conduction  and  is  not  to  be  confounded 
with  the  phenomena  of  electrical  radiation, 
which  have  heretofore  been  observed,  and 
which,  from  the  very  nature  and  mode  of 
propagation,  would  render  practically  im- 
possible the  transmission  of  any  appreciable 
amount  of  energy  to  such  distances  as  are 
of  practical  importance." 


Two  Views  of  the  Last 
Minutes  of  Tesla's  Gigan- 
tic Radio  Tower  at  Shore- 
ham,  L.  I.,  New  York,  As 
It  Was  Being  Demolished 
by  the  Federal  Govern- 
ment. It  Was  Suspected 
That  German  Spies  Were 
Using  the  Tower  for  Ra- 
dio -  Communication  Pur- 
poses. It  Stood  185  Feet 
Above  the  Ground  and 
Cost  About  $200,000.  Tesla 
Had  Not  Used  It  For  Sev- 
eral Years. 

Photos  by  Ameiican  Press  Association 


294 


THE  ELECTRICAL  EXPERIMENTER 


September,  1917 


"Our  Navy"  On  The  Stage 

By  GEORGE  HOLMES 


THE  electrical  engineer  who  was  art- 
ist and  dreamer  as  well,  has  again 
outdone  the  common -place.  A  spec- 
tacular theatrical  effect  is  now  play- 
ing in  New  York,  which  besides  giv- 
ing further  publicity  to  "Our  Navy,"  bids 
fair  to  rival  Uncle  Sam's  big  fleet  in 
awe-inspiring  and 
realistic  thrill. 
Electricity  plays 
the  master  role  in 
this  wonderful 
spectacle,  which 
has  become  the 
talk  of  Broad- 
way. 

At  the  rise  of 
the  curtain  we  see 
a  golden  sunset 
with  the  sun 
slowly  sinking  in 
the  west  and 
night  gradually 
approach- 
ing. With  a  hush 
we  watch  a  fleet 
of  war  ships  in 
battle  formation 
steaming  toward 
us  on  the  distant 
horizon.  They 
gradually  draw 
nearer,  increas- 
ing to  three  times 
their  original  (or 
life)  size,  and  as 
they  get  immedi- 
ately before  us, 
we  get  a  sensa- 
tion as  if  the 
ships  are  going 
to  bear  down  up- 
on us.  This  real- 
istic illusion  is 
based  upon  the 
scientific  princi- 
ple of  perspec- 
tive ;  viz.,  the 
further  away  an 
observer  is  from 
an  object  the 
smaller  it  appears 
to  the  eye ;  and 
that  every  particle 
of  the  object's 
contour  increases 
in  exact  propor- 
tion as  it  enlarges 
in  approach. 

Each  ship  is 
electrically  oper- 
ated and  con- 
trolled by  a  single 
operator,  who 
manipulates  the 
numerous  and 
various  devices 
by  means  of 
switches,  push 
buttons  and  rheo- 
stats, all  of  which 
are  located  on  a 
massive  switch- 
board on  the  rear 
of  each  ship. 

The  motive 
power  under  the 
control  of  each 
operator  is  sup- 
plied by  two  large 
electric  motors  which  are  connected  to  the 
various  parts  of  the  apparatus  by  gears, 
belts  and  chains,  thus  enabling  the  ships 
to  appear  to  travel  slow  or  faster  in  their 


approach  as  desired.  Each  ship  has  its  own 
set  of  motors,  belts,  chains  and  gears.  An 
electrically  heated  boiler  furnishes  steam 
for  the  smoke  stacks.  The  cannon  are  fired 
by  electricity,  the  signal  lights  blink,  search- 
lights play  across  the  horizon  and  on  "Old 


paratus  was  built  in  his  New  York  studios, 
where  other  similar  theatrical  sensations 
like  "The  Honeymoon  Express"  and  "The 
Forest  Fire"  were  conceived  and  produced 
— proving  that  this  genius  accepts  the  stage 
as  having  no  limitations.  All  in  all  it  is 
probably  the  most  complex  and  true  to 
nature  theatrical 
effect  ever  pro- 
d  u  c  e  d  on  any 
continent. 

A  few  more 
electrically  oper- 
a  t  e  d  spectacles 
like  this  one 
would  seem  a  big 
national  stimulus 
toward  recruit- 
ing. Who  can  sit 
and  witness  such 
a  stirring  scene 
without  feeling 
the  red-blooded 
desire  to  be  up 
and  doing  some- 
thing patriotic, 
even  to  buying 
Liberty  Bonds. 


New  York  Stage  Produce 
"Our  Navy."    By  the  Aid 
Guns  Boom, 


rs  Have  Outdone  Themselves  In  Evolving  the  Great  Marine  Spectacle 
of  Electricity  These  Warships  Are  Made  to  Grow  Larger  and  Larger;  the 
Searchlights  Flash  and  Even  the  Smoke  Is  Not  Forgotten. 

Glory,"  making  a  truly  inspiring  and  last- 
ing impression  upon  the  audience. 

The  inventor  of  this  magnificent  spectacle 
is  Langdon  McCormick,  and  the  whole  ap- 


LIGHT  FROM 
THE  FISHES? 

Long  strides 
are  being  taken 
by  the  biological 
department  o  f 
Princeton  U  n  i  - 
versity  to  obtain 
light  without  heat. 
If  the  discovery 
fully  realizes  its 
expectations  i  t 
will  doubtless 
revolution- 
ize modern  light- 
ing.  Professors 
Edwin  Conklin, 
Ulric  Dahlgren 
and  Edmund  N. 
Harvey  are  work- 
ing on  luminous 
animals  in  an  at- 
tempt to  fathom 
the  cause  of  their 
luminosity,  which 
is  99  per  cent 
light.  Modern 
electric  light  pro- 
duces only  from 
2%  to  3%  light, 
the  rest  being 
wasted  in  heat. 

Professor  Har- 
vey obtained  a 
consider- 
able  quantity  of 
the  luminous  ma- 
terial from  small 
fish  found  in 
Japan.  He  has 
partly  analyzed 
the  substance, 
finding  that  like 
the  proteids  of 
the  living  bodies 
it  can  be  kept  for 
years  by  drying 
it  and  sealing  it 
in  vacuum  tubes. 
When  released, 
moistened  and 
exposed  to  oxy- 
gen it  will  light 
into  a  clear,  bluish  phosphorescent  flame. 

The  substance  is  very  powerful,  as  it 
is  still  visible  when  one  part  of  it  is  diluted 
in   1,700,000  parts   of  water. 


September,  1917 


THE  ELECTRICAL  EXPERIMENTER 


295 


SQUIRTED  TUNGSTEN 
FILAMENTS. 

Some  interesting  particulars  of  a  pecu- 
liar method  of  preparing  tungsten  fila- 
ments, which  are  ductile  in  spite  of  being 
squirted,  are  cited  in  Engineering,  Lon- 
don. 

The  process,  which  was  described  by  Dr. 
W.  Bottyer  before  the  December  meeting 
of  the  Bunsen  Gesellschaft,  is  employed 
by  Julius  Pintsch,  and  is  due  to  Messrs. 
O.  Schaller  and  Orbig.  Members  of  the 
society  were  able  to  watch  the  process  in 
the  works  after  the  meeting.  The  metallic 
powder  is  mixed  with  2  per  cent,  of  thoria 
and  kneaded  into  a  paste  with  addition 
of  some  binding  agent;  a  thread  is  then 
squirted.  The  thread  is  first  pre-heated 
and  then  rapidly  heated  up  to  2,400°  C. 
or  2,600°  C,  the  object  being  to  make  the 
crystallization  of  the  metal  more  rapid 
than  the  passage  of  the  wire  thru  the  hot 
zone.  The  first  apparatus  used  for  this 
delicate  operation  had  the  dimensions  of 
several  meters ;  the  actual  apparatus  is  only 
a  few  centimeters  in  height.  The  result- 
ing wire  is  said  to  consist  of  crystals  sev- 
eral meters  in  length,  tho  only  a  few  hun- 
dredths of  a  millimeter  in  thickness,  the 
cross-section  of  the  wire  conies  out  octago- 
nel  rather  than  circular.  There  are  very 
few  joints  in  a  wire.  A  re-crystallization 
of  the  filament  after  long-continued  use 
of  the  lamp  is  said  not  to  occur. 


causes  a  movable  contact  drum  to  close  the 
individual  circuits  to  the  various  electric 
flashlight  stands  progressively,  as  the  camera 
turns  to  take  in  the  complete  view. 

This  arrangement  should  prove  extremely 
practical  and  of  great  service  to  commercial 


powder  is  ignited  all  in  one  spot  or  in  two 
or  three  spots. 


FOILING  THE  TRAIN  ROBBER 
WITH  RADIO. 

A  number  of  American  railroads  have 


ELECTRICITY   OPERATES  PANO- 
RAMA CAMERA  AND  FLASH- 
LIGHTS AUTOMATICALLY. 

The  accompanying  illustration  shows  a 
novel  idea  recently  evolved  by  a  New  York 
inventor,  Mr.  George  Wall,  by  which  it  be- 
comes possible,  thanks  to  the  flexibility  of 
electrical  control,  to  take  large  photographs, 
particularly  those  of  a  panoramic  nature  in- 
side buildings,  such  as  power  houses,  etc. 
A  small  battery  box  which  can  be  carried 
by  the  photographer  supplies  the  small 
quantity  of  electrical  energy  necessary  in 
igniting  the  flashlight  powder,  which  is 
placed  in  proper  containers  on  a  series  of 
telescopic  flashlight  stands.  The  electric 
panoramic  camera  is  specially  designed,  so 
that  once  the  photographer  has  it  focust 


Now  That  Wireless  From  Moving  Trains  Has  Been  Demonstrated  As  Practical,  We  May 
Expect  to  Read  In  Future  Train  Robbery  Accounts  That  the  Brave  and  Heroic  Radio  Operator 
Stuck  to  His  Post  Until  His  Frantic  Distress  Signals  Brought  the  Police. 


photographers  who  are  confronted  with  the 
problem  of  photographing  large  interiors, 
machinery,  etc.,  which  are  often  extremely 
difficult  to  handle  with  ordinary  cameras. 
With  Mr.  Wall's  invention  properly  ap- 
plied, the  panorama  camera  swings  around 
the  circle  for  the  number  of  degrees  de- 
sired, and  lights  up  each  part  of  the  scene 


A  New  Photographic  Scheme  Involving  the  Application  of  Electricity  to  Rotate  a  Panorama 
Camera  and  to  Ignite  a  Series  of  Flash-Lights  Successively  and  At  the  Proper  Instant.  In 
This  Way  an  Even  Illumination  of  the  Scene  Is  Assured. 


to  take  in  the  proper  view  as  it  swings  about 
on  its  tripod,  propelled  by  means  of  special 
gears  and  a  miniature  electric  motor  (oper- 
ated from  the  battery  before  mentioned),  it 


progressively  as  it  turns ;  thus  giving  a 
very  uniformly  illuminated  picture,  which  is 
very  difficult  to  obtain  with  the  usual  style 
of  concentrated  flash  where  the  magnesium 


experimented  with  wireless  installations  on 
moving  trains  and  exceptional  results  have 
been  obtained  in  many  instances,  the  mes- 
sages having  been  transmitted  over  dis- 
tances of  75  to  100  miles  from  the  train 
while  in  motion.  These  considerations  have 
led  a  New  York  genius,  Mr.  George  Wall, 
to  suggest  that  all  trains  traversing  barren 
parts  of  the  country  such  as  the  prairies 
of  the  West  and  Southwest  be  provided 
with  wireless  apparatus  particularly  for 
use  in  summoning  police  aid  in  the  event 
of  being  held  up  by  train  robbers. 

Albeit,  this  is  not  such  a  far-fetched  idea 
at  that,  as  we  read  quite  often  of  a  train 
being  held  up,  even  in  this  latter  age  of 
enlightenment  and  civilization.  As  the  un- 
settled regions  of  the  country  are  becom- 
ing rapidly  populated,  at  least  to  a  fair  ex- 
tent, and  as  mounted  police  are  to  be  found 
at  relatively  short  distances  in  practically 
every  part  of  the  United  States,  the  sug- 
gestion seems  very  logical,  and  undoubtedly 
when  the  present  war  situation  has  past 
away,  the  leading  railroads  will  foresee  the 
distinct  advantages  and  facilities  provided 
by  installing  radio-telegraphic  sets  on  all 
trains  passing  thru  unsettled  parts  of  the 
country. 

Not  only  will  the  radio  prove  exception- 
ally valuable  in  many  such  instances  as 
that  here  illustrated,  but  it  has  already 
proven  of  extreme  efficacy  in  the  handling 
of  trains.  It  may  in  this  way  often  be 
the  means  of  averting  a  serious  train 
wreck,  especially  when  severe  storms  have 
caused  bad  washouts  along  the  line  and 
dismantled  the  telegraphic  and  telephone 
wires.  One  eastern  railroad,  the  Dela- 
ware, Lackawanna  and  Western,  has  tried 
out  a  wireless  train  installation  with  excel- 
lent satisfaction,  and  found  it  of  great 
practical  use  in  the  dispatching  of  trains 
during  the  winter  months,  when  severe 
storms  had  demolished  part  of  the  com- 
munication lines. 


296  THE  ELECTRICAL  EXPERIMENTER  September,  1917 

All  Aboard  for  "  Luna's"  Electric  Top 


ONE  of  the  largest  and  most  inter- 
esting rides  ever  constructed  at 
Coney  Island,  New  York's  famous 
pleasure  park,  is  "The  Top,"  which 
is  one  of  Luna's  latest  amusement 
devices.    It  is  an  immense  structure,  seven- 


ty-five feet  in  diameter  and  eighty  feet 
high,  and  follows  closely  the  design  of  an 
ordinary  spinning  top.  There  are  two 
sets  of  tracks,  one  on  the  outer  and  the 
other  on  the  inner  rim,  with  the  cars 
operated  by  a  third-rail  system.  The  entire 
ride  covers  nearly  one  mile.  Forty-five 
tons  of  steel  were  used  in  the  construction, 
and  the  ride  in  its  finished  condition,  with 
equipment,  carries  fifty  tons,  all  of  which 
rests  upon  a  solid  concrete  foundation. 

It  is  an  electrical  achievement  which  has 
been  accomplisht  after  several  years  of 
study  and  experimenting.  One  of  the 
greatest  problems  that  has  been  solved  is 
the  transmission  of  current  to  the  wheel 
which  is  revolving  on  a  shaft  resting  in  a 
pivot  socket,  as  shown  in  the  drawing, 
while  the  shaft  is  at  all  times  resting  at 
an  angle  of  about  15  degrees  from  the 
horizontal.  The  lighting  and  operating 
current  is  transmitted  from  the  socket  pit 
by  means  of  stationary  contact  rings  and 
a  floating  brush  arm  carried  on  the  shaft. 
The  necessary  electric  current  for  the  mo- 
tor car  and  lamps  (night  illumination)  is 
thus  conveyed  thru  the  revolving  brush 
arm  and  brushes. 

No  great  electrical  driving  force  is  re- 
quired, as  the  shifting  weight  of  the  mo- 
tor cars  on  the  outside  rim  drives  forward, 
by  gravity,  the  cars  (without  motors)  on 
the  inner  rim  up  an  incline  to  a  height  of 
thirty  feet. 

Four  motors,  each  of  seven  and  one- 
half  horse  power,  are  used  in  the  oper- 
ating. These  are  fitted  to  the  motor  car 
running  on  the  outer  rim.  In  loading  po- 
sition the  "top"  is  so  designed  that  all  three 
passenger  cars  are  on  the  lowest  level  of 
each  of  the  three  independent  tracks,  and 
all  in  line  before  the  gate.  Passengers 
may  thus  pass  thru  the  first  car  to  the 
second  and  third  cars.  The  two  inner 
cars  are  always  slightly  behind  the  (outer) 


motor  car  when  the  "top"  is  running. 

The  passengers  in  the  inner  cars  enjoy 
the  most  sensations,  rising  and  falling  as 
the  "top"  whirls  around.  The  outer  motor 
car  keeps  at  an  average  elevation  of  15 
feet  above  the  ground,  but  owing  to  the 


track  (and  "top")  continually  rolling,  the 
motor  and  other  cars  eventually  swing 
around  a  complete  circle.  The  "top"  has 
to  make  fifteen  complete  revolutions  for 
a  "ride",  so  as  to  bring  all  the  cars  back 
to  the  lowest  track  levels  and  in  line  be- 
fore the  gate. 

Luna  Park  has  augmented  its  brilliancy 
by  the  addition  of  thirty-two  posts,  each 


with  five  three  hundred  watt  lamps.  Placed 
at  equal  distances  apart  and  in  the  center 
of  the  main  concourse,  they  have  bright- 
ened the  entire  park.  The  concourse  is  now 
known  as  Luna's  White  Way. 


EXTENSION  TO  C,  M.  &  ST.  PAUL 
RAILWAY  ELECTRIFICATION 
PROGRESSING. 

That  part  of  the  Chicago,  Milwaukee  & 
St.  Paul  Railroad  between  Harlowton, 
Mont.,  and  Avery,  Idaho,  a  distance  of 
437  miles,  is  now  being  operated  as  an 
electric  line.  Electric  power  is  supplied 
by  various  plants  of  the  Montana  Power 
Company,  the  largest  two  of  these  being 
at  Great  Falls,  Mont,  and  Thompson  Falls, 
Idaho.  The  first  electric  train  was  moved 
in  December,  1915,  and  the  last  steam-oper- 
ated train  was  taken  off  the  Missoula  divi- 
sion in  February,  1917.  On  that  division 
is  the  St.  Paul  Pass  tunnel,  which  cuts 
thru  the  summit  of  the  Bitter  Root  moun- 
tain range  near  the  Montana-Idaho  line, 
and  has  a  length  of  8,000  ft. 

The  work  of  electrifying  another  divi- 
sion, of  217  miles,  began  about  May  16, 
1917.  The  starting  point  is  at  Othello, 
100  miles  east  of  Cle  Elum,  and  electrifi- 
cation will  proceed  westerly  to  Seattle  and 
Tacoma.  Power  will  be  furnished  by  the 
Intermountain  Power  Company.  It  is  fig- 
ured that  the  work  will  be  completed  be- 
tween Cle  Elum  and  Seattle  and  Tacoma 
before  the  close  of  1918. 


JACK  BINNS  ENLISTS  IN  BRITISH 
ARMY. 

Prominent  among  the  applicants  answer- 
ing the  call  for  British  recruits  in  Amer- 
ica, was  Jack  Binns,  the  wireless  operator, 
whose  messages  from  the  liner  Republic 
on  Jan.  23,  1909,  brought  rescue  ships  after 
she  had  been  rammed  by  a  freighter.  Jack 
gave  up  the  sea  soon  after  the  sinking  of 
the  Republic  and  took  up  newspaper  work. 
Binns  is  thirty-two,  married  and  has  two 
children.  He  was  injured  in  a  train  wreck 
and  could  claim  exemption,  but  would  not. 


Illustrating  In  Detail  How  Luna's  Wonderful  Electric  "Top"  Is  Operated.    Its  Central  Shaft 
Rests  On  a  Cone  Bearing  and  the  Climbing  Movement  of  the  Outer  Motor-Car  Causes  the 
Whole  Structure  to  "Roll"  Around,  Propelling  the  Inner  Cars  By  Gravity  Alone 


Cor/oad/ng 
position 


Speed  of  reyo/y/ng 
top  25 m/'/es perfioar 


Z  'Top"  75  feet 
'  diameter  and 
so  feet  high 


When  'motor' cor gefs here) 
'Top'  starts  m  Mis  direction         Mrs  to  motors 
by  grow  ft/  and '  //gfifs 


Contact 
rings 


E/ectric  feed 
wires 


Coney  Island,  New  York's  Supreme  Play-Ground  for  Grown-Ups  and  Youngsters  Alike,  Now 
Boasts  Something  Real  New  In  Amusement  Devices.  You  Board  a  Small  Car  and  Before  You 
Know  It  You  Are  Whirling  Around  the  Spiral  Track  of  "The  Top,"  As  Luna  Calls  It.  This 
Gigantic  Electric  "Top,"  80  Feet  High  By  75  Feet  In  Diameter  Rotates  at  a  Speed  of  25  Miles 

Per  Hour. 


September,  1917 


THE  ELECTRICAL  EXPERIMENTER 


297 


Transmitting  Sound  by  Phonograph  and  Telephone  104 

Miles,  Thru  48  Physical  Changes 


/  ^ 


J  /  <r 


APPARATUSAT 
/6  cortlahdt  sr 

-ft£W  YORK  CITY 


TELEPHONE 


APPARATUS  Ar  F/WWL/N  /HST/TOTE 
PMLAOEL  P>NA,  P/P 


NEW  YORK  END  Of  LINE 


PHILADELPHIA  END  OF  LINE 


SUBMARINE  CABLE  UNDERGROUND 
I ONG  DISTANCE  TELEPHONE  COTIPANIEF'L/NES  CASLS 
/Of  MILES  LONG 
J IX  MILES  UNDERGROUND  AND  t/NDEPWATEP 

One  of  the  Most  Remarkable  Telephonic  Demonstrations  Ever  Attempted  Is  That  Here  Illustrated.    By  Means  of  Phonographs  a 
speaking  Telephones  the  Human  Voice  Was  Transmitted  Thru  a  Series  of  48  Physical  Changes,  15  Different  Mediums  and  Thru 
Times,  Between  New  York  and  Philadelphia.    Mr.  Hammer,  Who  Engineered  This  Stunt,  Was  Awarded  the  "Franklin  Medal"  in 

the  Occasion. 


nd  Loud- 
the  Air  5 
Honor  of 


SOME  years  ago  when  telephony 
was  still  quite  a  youngster,  one  of 
the  most  interesting  and  remark- 
able scientific  demonstrations  in- 
volving several  of  Thomas  A.  Edi- 
son's great  inventions,  including  the  phono- 
graph, were  demonstrated  by  a  New  York 
Electrical  Engineer,  Mr.  William  J.  Ham- 
mer. 

Mr.  Edison  was  very  highly  pleased  with 
this  really  beautiful  piece  of  engineering 
and  scientific  technique,  which  not  only 
seemed  impossible  of  accomplishment  by 
the  leading  telephone  engineers  of  the  day, 
but  which  also  retained  and  involved  the 
demonstration  of  several  Edison  inven- 
tions. 

This  remarkable  experiment  in  the  pho- 
nographic and  telephonic  transmission  of 
sound  took  place  between  New  York  and 
Philadelphia,  over  104  miles  of  telephone 
cables,  six  miles  of  which  were  under 
ground  and  under  water,  as  the  illustration 
here  shown  clearly  indicates.  This  novel 
experiment  was  shown  by  Mr.  Hammer  in 
his  lecture  on  "Edison  and  His  Inventions," 
delivered  before  the  Franklin  Institute  at 
Philadelphia.  It  employed  two  Edison 
phonographs,  two  Edison  carbon  transmit- 
ting telephones,  two  Edison  motograph  re- 
ceivers or  loud-speaking  telephones,  two 
sets  of  induction  coils  and  batteries  and 
104  miles  of  long-distance  telephone  cir- 
cuit as  before  mentioned ;  98  miles  of  this 
circuit  consisting  of  wire  strung  on  poles. 

In  this  experiment  in  which  three  of  Mr. 
Edison's  wonderful  inventions  were  shown 
working  in  juxtaposition,  it  will  be  ob- 
served that  the  sounds,  which  consisted  of 
talking,  singing  and  cornet  playing,  were 
transmitted  thru  the  air  five  times  and  were 
transmitted  thru  no  less  than  fifteen  dis- 
tinct mediums,  from  the  speaker  and  mu- 
sician in  New  York  to  the  audience  in  the 
Franklin  Institute  in  Philadelphia. 

These  mediums  included  vocal  chords, 
cornet,  air,  glass,  iron  and  mica  diaframs, 
carbon  buttons,  styli  of  steel,  palladium- 
faced  pens  or  springs,  hydrogen  gas,  dis- 
tilled water,  wax  and  chalk  cylinders,  cop- 
per wire  and  the  mechanism  of  the  ear. 

The  physical  characteristics  of  the  sound 
waves  were  changed  during  transmission 
no  less  than  48  times,  as  follows:  (1)  Air 
waves  produced  by  vibration  of  the  vocal 
chords  in  the  speaker's  throat  or  by  the 
cornet.  (2)  Vibration  of  the  glass  dia- 
fram  of  the  phonograph  recorder,  produc- 
ing variations  in  curvature  of  the  diafram. 
(3)  Variation  in  longitudinal  stress  of  the 
steel  stylus  attached  to  glass  recording  dia- 
fram. (4)  Undulations  in  the  wax  cylinder 
of  the  phonograph.  (5)  Variation  in  the 
longitudinal  stress  of  the  steel  stylus  at- 
tached to  diafram  of  phonograph  repro- 


ducer. (6)  Vibration  of  the  glass  diafram 
of  the  phonograph  reproducer  producing 
variations  in  curvature  of  diafram.  (7) 
Sound  waves  thru  the  air.  (8)  Vibra- 
tions of  the  iron  diafram  of  the  carbon 
transmitter  producing  variations  in  curva- 
ture of  the  diafram.  (9)  Varying  pres- 
sures on  the  carbon  button,  varying  the  re- 
sistance of  the  carbon  exactly  in  accord- 
ance with  the  number  and  amplitude  of  the 
vibrations  of  the  diafram.  (10)  Pulsatory 
current  produced  in  the  primary  winding 
of  the  induction  coil.  (11)  Undulating 
magnetic  force  produced  in  the  iron  core  of 
the  coil.  (12)  Alternating  electric  cur- 
rents in  secondary  winding  of  the  coil. 
(13)  Minute  Eddy  currents  appearing  in 
copper  wires  of  the  primary  and  secondary 
windings  of  coil  and  in  the  iron  core  of 
the  coil.  (14)  Heat  produced  by  Eddy  cur- 
rents. (IS)  Magnetic  hysteresis  in  iron  core 
formed  in  overcoming  molecular  friction 
in  the  iron  caused  by  reversals  of  polarity. 

(16)  Heat  produced  by  hysteresis  in  iron. 

(17)  Infinitesimal  variation  in  length  of 
iron   core    due    to    magnetizing  currents. 

(18)  Moving  electro-static  flux  on  the  line 
accompanied  by  or  producing  electromag- 
netic flux  around  the  wire.  (19)  Heat 
produced  by  passage  of  electric  current 
thru  the  wire.  (20)  Variation  of  the  co- 
efficient of  friction  between  the  surface  of 
chalk  cylinder  and  palladium-faced  pen  or 
spring  of  the  motograph  receiver.  (21) 
Electrolytic  action,  causing  evolution  of  hy- 
drogen and  oxygen  between  the  chalk 
cylinder  and  palladium-faced  spring  of  the 
motograph  receiver.  (22)  Electro-capillary 
action,  forcing  moisture  to  the  surface  of 
the  chalk  cylinder  of  motograph  receiver. 
(23)  Variation  in  longitudinal  stress  of  bar 
or  spring  attached  to  mica  diafram  of  the 
motograph  receiver.  (24)  Vibration  of  the 
diafram  of  motograph  receiver  produc- 
ing variations  in  curvature  of  the  diafram. 
(25)  Sound  waves  thru  the  air.  (26) 
Vibrations  of  glass  diafram  of  phonograph 
transmitter  producing  variations  in  curva- 
ture of  diafram.  (27)  Variation  in  longi- 
tudinal stress  of  steel  stylus  attached  to 
glass  transmitting  diafram.  (28)  Undula- 
tions in  wax  cylinder  of  the  phonograph. 
(29)  Variations  in  longitudinal  stress  of 
steel  stylus  attached  to  glass  reproducing 
diafram.  (30)  Sound  waves  thru  the  air. 
(31)  Vibrations  of  iron  diafram  of  car- 
bon transmitter,  producing  variation  of 
curvature  of  iron  diafram.  (32)  Varying 
pressure  on  carbon  button,  varying  the  re- 
sistance of  the  carbon  exactly  in  accord- 
ance with  the  number  and  amplitude  of  the 
vibrations  of  the  diafram.  (33)  Pulsatory 
current  produced  in  the  primary  winding 
of  the  induction  coil.  (34)  Undulating 
magnetic   force   in   the   iron   core   of  the 


coil.  (35)  Alternating  electric  current  in 
secondary  winding  of  the  coil.  (36)  Min- 
ute Eddy  currents,  appearing  in  copper 
wires  of  the  primary  and  secondary  wind- 
ings of  coil  and  in  the  iron  core  of  the 
coil.  (37)  Heat  produced  by  Eddy  cur- 
rents. (38)  Magnetic  hysteresis  in  iron 
core  formed  in  overcoming  molecular  fric- 
tion in  the  iron  by  reversal  of  polarity. 
(39)  Heat  produced  by  hysteresis.  (40) 
Infinitesimal  variation  in  length  of  iron 
core  due  to  magnetizing  currents.  (41) 
Moving  electrostatic  flux  on  the  line  ac- 
companied by  or  producing  electromagnetic 
flux  around  the  wire.  (42)  Variation  of 
the  coefficient  of  friction  between  the  sur- 
faces of  chalk  cylinder  and  pailladium- 
faced  pen  or  spring  of  the  motograph  re- 
ceiver. (43)  Electrolytic  action  causing 
evolution  of  hydrogen  and  oxygen  between 
the  chalk  cylinder  and  palladium- faced 
spring  of  the  motograph  receiver.  (44) 
Electro-capillary  action  forcing  moisture  to 
the  surface  of  the  chalk  cylinder  of  the 
motograph  receiver.  (45)  Variation  in 
longitudinal  stress  of  bar  or  spring  at- 
tached to  mica  diafram  of  the  motograph 
receiver.  (46)  Vibration  of  the  diafram 
of  the  motograph  receiver  producing  vari- 
ations in  curvature  of  the  diafram.  (47) 
Sound  waves  thru  the  air.  (48)  Transla- 
tion of  sound  waves  into  words  by  the 
auditory  nerves  and  other  mechanism  of 
the  ears  of  the  audience  at  Philadelphia. 
By  means  of  transmitters  placed  upon  the 
stage,  the  lecture  was  listened  to  by  audi- 
ences in  fourteen  different  cities. 


THE  FRANKLIN  MEDAL  AWARDS. 

The  Franklin  Medal,  which  is  awarded 
annually  by  the  Franklin  Institute,  Phila- 
delphia, Pa.,  to  "those  workers  in  physical 
science  or  technology,  without  regard  to 
country,  whose  efforts,  in  the  opinion  of 
the  Institute,  have  done 'most  to  advance 
a  knowledge  of  physical  science  or  its  ap- 
plications," were  awarded  May  16  to  Hen- 
drik  Antoon  Lorentz,  president  of  Royal 
Academy  of  Science,  Amsterdam,  and  pro- 
fessor of  mathematical  physics,  University 
of  Leyden,  in  recognition  of  his  "researches 
which  have  so  largely  contributed  to  lay- 
ing on  a  new  foundation  our  knowledge 
of  the  nature  of  light  and  in  developing 
our  ideas  concerning  the  ultimate  consti- 
tution of  matter" ;  also  to  David  Watson 
Taylor,  chief  constructor  and  chief  of 
Bureau  of  Construction  and  Repair. 
United  States  Navy,  in  recognition  of  his 
"fundamental  contributions  to  the  theory 
of  ship  resistance  and  screw  propulsion, 
and  of  his  signal  success  in  the  applica- 
tion of  current  theory  to  the  practical  de- 
sign of  varied  types  of  war  vessels  in  the 
United  States  Navv." 


298 


THE  ELECTRICAL  EXPERIMENTER 


September,  1917 


Electric  "Bloodhounds"  to  Find  and  Destroy  U-Boats 


magnet.  8-  Induction  bo/once  apparatus.  9-  Fxp/os/ve  chamber  /0-£lednc  detonator.  11 -Diving  plane  control  solenoids. 
12- Cable  drum.  15- Electric  Cyroscope.  t4- Batteries.  15- Mo.  retease.  J6- Bolt  float.  17-  Pilot  tamp.  16-  Position  flag. 
19- Solenoid  control  relays  etc.  20- 11. Res.  sensitive  relays.  21-  Amplifiers.  22-Pudder  control 'solenoid.  2S- Microphone. 


NO  one  will  deny  the  fact  that  the 
modern  U-boat  owes  its  deadliness 
to  its  invisibility.  The  submarine 
operates  upon  the  time-old  princi- 
ple of  waylaying  its  quarry,  hidden 
in  the  dark  from  the  view  of  its  victim. 
The  victim,  unsuspecting  of  the  waylayer 
is  stabbed  in  the  back,  at  the  opportune 
moment  when  the  bandit  feels  himself  safe 
from  counter  attack. 

Were  the  U-boat  to  operate  in  a  per- 
fectly transparent  medium — such  as  the  air 
for  instance — we  would  not  have  much 
trouble  in  hunting  it  down  soon.  It  is 
plain  that  we  could  then  go  after  it  with 
our  own  submarines,  or  on  the  other  hand, 
merchant  steamers  would  see  the  U-boat 
long  before  it  could  fire  a  torpedo,  and  in 
such  a  case  the  ship  could  be  maneuvered 
quickly,  making  a  torpedo  hit  unlikely. 

Unfortunate- 
ly water  is  far 
from  transpa- 
rent.  To  all 
practical  pur- 
poses it  is  as 
opaque  as  a 
brick  wall. 
Therefore,  in- 
ventors who  are 
apt  to  fight  sub- 
marines —  on 
p  a  p  e  r — b  y 
means  of 
powerful  sub- 
merged search- 
lights should  do 
well  to  remem- 
ber that  even 
the  strongest 
light  rays  do 
not  penetrate 
the  ocean  more 
than  300  feet  at 
a  depth  of  25 
feet  below  sea  level. 

Coming  back  to  our  analogy  of  the  ban- 
dit, everyone  knows  that  while  our  own 
senses  are  more  or  less  imperfect,  this  is 
not  the  case  of  the  senses  of  certain  ani- 
mals. Thus  if  you  fear  an  attack  on  a 
lonely  road,  you  probably  would  take  along 
a  good  dog  if  you  owned  one,  reasoning 
that  the  dog  would  smell  and  hear  the 
bandit  in  time  and  thus  warn  you.  Also 
the  dog  would  probably  show  you  the  direc- 
tion in  which  the  waylayer  is  located,  and 
if  you  were  armed,  you  could  "go  for  the 
bandit."  All  this  irrespective  if  it  was  in 
bright  sunlight  or  on  a 
dark  night.  — ^— — 

Applying  this  reasoning 
to  the  present  submarine 
war,  we  find  that  if  we  can 
design  the  mechanical 
counterpart  of  a  real  blood- 
hound, the  invulnerability 
of  the  U-boat,  i.e.,  its  in- 
visibility, will  be  wiped 
out. 

With  this  in  mind  the 
authors  have  devised  an 
electro-mechanical  "blood- 
hound"   which  functions 

upon  the  same  principle  as   

his  live  brother  on  land.  '^mm^^^^^m 
While  the  live  bloodhound 
is  mainly  guided  by  his  hearing  and  by  his 
smell,  the  authors'  machine  operates  only 
by  "hearing." 

Briefly,  the  idea  consists  of  equipping  a 
standard  torpedo  with  a  number  of  super- 
sensitive microphones,  which  are  provided 
with  certain  tone- filters,  well  known  to 
electrical    engineers.    Now,    a  submarine 


By  H.  GERNSBACK  and  H.  W.  SEGOR 

must  run  its  electric  motors  when  running 
under  water,  and  these  motors  of  necessity 
make  quite  a  good  deal  of  noise.  In  fact, 
the  sound  of  submarines  has  been  detected 
with  micro phone-audion  units  for  over  20 
miles.    This  is  a  well  established  fact. 

While  on  the  other  hand  we  have  it  on 
good  authority  that  of  late  German  U-boats 
mount  their  motors  on  felt  and  other  sound 
deadening  substances,  the  fact  remains  that 


And  like  the  flesh  and  blood  dog,  the 
electric  "bloodhound"  guides  us  by  a  rope. 
In  this  case  the  rope  is  an  electrical  cable 
thru  which  the  current  passes  to  drive  its 
propelling  motors.  The  cable  contains  other 
wires,  too,  as  will  become  apparent  later. 
The  cable  itself  runs  to  the  fast  motor  boat 
chaser,  which  we  own  already,  but  which 
are  rather  ineffective  today,  due  to  their 
blindness ;  i.  e.,  they  can  neither  see  nor 
smell  submerged  U-boats.  Given  a  hun- 
dred submarine  motor  boat  chasers  equipt 
with  the  authors'  sound-controlled  tor- 
pedoes, it  should  be  possible  to  rid  the 
oceans  from  the  U-boats  in  a  few  months' 
time.  Once  the  enemy  sees  that  a  large 
number  of  his  submarines  are  sunk,  he  is 
likely  to  come  to  his  senses  and  give  up  the 
game. 

Now,  the  au- 
thors, who  have 
carefully  gone 
into  all  of  the 
details,  find  that 
the  idea  is  en- 
tirely practical 
and  feasible.  For 
obvious  reasons, 
not  all  of  the  de- 
tails and  refine- 
ments are  made 
public  at  this 
time,  and  this  ar- 
ticle is  published 
with  a  view  of 
setting  other  able 
workers  to  think 
along  similar 

l-3rassrod.  2- Iron.  3- Bronze  or  gun -mefot  she// lip.  4-Microphone.  5-  Powrfw 'ho/ding moppet.  6-/roncore.  7 -Telegraphing  lmes. 


24- Motor.  25-  Shaft.  26- Rudders.  27-  Prvpe/lers. 

Fig.l 


the  sound  of  a  600  horsepower  electrical 
motor  of  a  submarine  cannot  be  deadened 
entirely.  Then  too — and  this  will  be  a  sur- 
prise to  the  layman — sound  travels  much 
better  and  farther  in  water  than  in  the  air. 
(If  you  don't  think  so,  next  time  you  are 
in  your  bath  tub,  submerge  both  ears  in 
the  water  and  slightly  rub  two  fingers  to- 
gether, under  the  water,  of  course.  You 
will  be  surprised  how  well  you  can  hear 
the  slightest  noises.)  Therefore,  even  if 
the  enemy  submarine  muffles  its  motors, 
we  will  still  be  able  to  hear  the  U-boat 
machinery  over  a  distance  of  several  miles. 


Hunting  the  submarine  in  its  own  lair  by  an  electro-mechanical 
"bloodhound"  is  proposed  in  this  interesting  article.  The  idea  is  to  steer 
a  torpedo  by  the  sound  of  the  submarine  propellers.  Certain  sensitive 
microphones  on  the  torpedo  cause  the  latter  to  "go  for"  the  U-boat  and 
blow  it  up. 


And  that  is  all  we  require. 

Our  electro  -  mechanical  "bloodhound" 
then,  thanks  to  his  electric  brain  and  his 
electric  motors,  will  start  at  once  in  the 
direction  of  the  U-boat,  as  soon  as  he  picks 
up  its  noise.  Just  as  his  live  brother,  he 
will  then  guide  us  to  the  invisible  enemy  as 
certain  as  fate. 


It    is  thought 
that  even  if  the 
enemy  should  be- 
©       come  aware  of 
the  plan,  no  harm 
would    be  done, 
because  there  does  not  seem  to  be  a  defense 
against  the  proposed  scheme.    Also  by  pub- 
lishing the  idea  thousands  of  people  will 
become  interested  in  it  with  the  very  great 
possibility  that  the  device  will  ■  be  greatly 
improved  upon  in  a  short  time. 

It  should  be  remembered  that  the  elec- 
tric "bloodhound"  contains  no  startling 
new  apparatus  or  machines,  nor  is  it  based 
upon  mere  theories  or  untried  ideas.  It 
makes  use  of  certain  well-known  apparatus 
and  devices,  the  only  new  thing  being  in 
their  application  and  disposition.  Any  fac- 
tory turning  out  torpedoes  now  will  be 
able  to  construct  the  new 
hmbm^^b  "U-Boat  Killer"  in  short 
order. 

It  should  also  be  borne 
in  mind  that  this  idea  does 
not  depend  entirely  upon 
the  principle  of  the  micro- 
phones "hearing"  the  hum 
of  the  motors  alone.  The 
Germans    might    in  time 
make  their  motors  entirely 
noiseless  —  altho   the  au- 
thors   very    much  doubt 
that  it  can  be  done.  There 
remains    the    very  loud 
^^^^^^^^     sound   of   the  propellers 
churning  the  water.  And 
this   cannot   be  supprest 
by  any  possible  means,  unless  the  U-boat 
lies   perfectly   still,   and   a   U-boat  can't 
always  lie  perfectly  still;   it  must  move 
some  time.    Then,  too,  during  the  night  it 
is  forced  to  come  up  to  the  surface,  run- 
ning its   Diesel   oil  engines   in  order  to 
charge  the  storage  batteries.    And  it  is 
{Continued  on  page  347) 


September,  1917 


THE  ELECTRICAL  EXPERIMENTER 


299 


€fje  &ob  of  tfje  &ub. 

By  Ed.  Schultz. 

Ten  ambitious  submarines 
Splashing  through  the  brine; 

One,  alas,  went  out  of  gas, 
Which  left  together  nine. 

Nine  aspiring  submarines 

Thrust  themselves  to  fate; 
One  dove  steep,  in  fact  too  deep ; 

Their  number  then  was  eight. 

Eight  aggressive  submarines 

Seeking  for  a  haven ; 
One,  take  note,  refused  to  float, 

Which  made  their  total  seven. 

Seven  alert  submarines 

The  enemy  went  to  "fix" ; 
They  all  went  fine,  till  a  floating  mine 

Reduced  the  fleet  to  six. 

Six  defying  submarines 

Ready  for  the  strife; 
They  then  took  count,  but  quickly  found 

That  really  they  were  five. 

Five  evading  submarines 

Skilled  in  ocean  lore ; 
All  went  well,  till  an  en'my  shell 

Diminished  them  to  four. 

Four  determined  submarines 

Terrorized  the  sea ; 
Their  reign  was  brief,  for  a  hidden  reef 

Curtailed  the  group  to  three. 

Three  desperate  submarines 

Beneath  the  ocean  blue ; 
While  there,  a  net  made  them  regret, 

Because  it  left  but  two. 

Two  dejected  submarines 

Their  voyage  nearly  done; 
One  'tis  plain  was  rammed  in  twain, 

For  now  remained  but  one. 


Electric  Tally-Board  Shows  Positions  of  Trains 

Constantly 

Do  you  ever  stop  to  think,  as  you  go     trains  with  a  guiding  hand,  always  with 
speeding  over   the  clicking   rails,   of   the     the  watchword  "safety  first"  in  mind, 
large  forces  of  men  and  the  numerous  de-        Practically  all  of  the  large  roads  have 


A  Tower  Director  at  the  "Grand  Central"  Terminal,  New  York  City,  with  His  Elaborate  Elec- 
trical Aide-de-Camp.    The  Various  Lamps  Show  the  Progress  of  Trains,  Confirmed  by  Tele- 
graph, Telephone  and  Telautograph. 


vices  and  appliances  that  watch  your  trip 
day  and  night  that  you  may  reach  your 
destination  safely?  Perhaps  few  of  us  give 
much  thought  to  this  all-important  matter. 


within  the  last  few  years  greatly  increased 
the  number  of  appliances  which  tend  to 
safeguard  the  public  and  at  the  same  time 
eliminate  the  human  factor  as  a  figure  in 
accidents,  making  every  mile  of  the  road 
always  visible  to  the  dispatchers.  In  the 
accompanying  photographs  may  be  seen 
views  of  the  large  electric  tally-boards  in 
the  dispatchers'  offices  on  a  great  eastern 
road.  These  boards  show  the  position  of 
all  trains  over  the  section  covered  by  that 
particular  office,  by  means  of  little  lights 
which  automatically  flash,  and  go  out  as 
the  train  advances  from  one  block  section 
to  another.  In  addition  to  this  new  device, 
the  dispatcher  has  also  the  telegraph  and 
telephone  to  aid  him.  In  this  way  it  is 
indeed  rare  that  collisions  occur,  as  the 
man  in  the  tower  or  dispatcher's  office  knows 
just  where  every  train  is  located  constantly. 


The  Twentieth  Century  Railroad  Tower  Director  Is  a  Very  Important  Person  a  geT*  Indeed!" 
To  Facilitate  the  Accurate  Handling  of  Trains  in  Complicated  Terminal  Yards  Electrical 
Tally-boards  Are  Provided  Which  Show  the  Exact  Position  of  Every  Train  by  Means  of  Lamps 


One  remorseful  submarine 
To  a  neutral  port  came  near ; 

It  there  sojourned  till  'twas  interned, 
Which  left  the  high  seas  clear. 


We  are  either  engrost  in  business,  or 
watching  the  scenery,  and  seldom  give  a 
second's  consideration  to  the  large  corps 
of  men  located  in  many  isolated  towers 
along  our  journey  watching  the  speeding 


STEEL  FOR  ELECTRICAL 
TRANSMISSION. 

In  a  recent  paper,  read  at  a  joint  meet- 
ing of  the  American  Institute  of  Electrical 
Engineers  and  the  Association  of  Iron  and 
Steel  Engineers,  Mr.  H.  B.  Dwight  empha- 
sises the  utility  of  steel  cables  for  trans- 
mission purposes  on  branch  lines,  espe- 
cially in  cases  where  the  size  of  copper 
strictly  required  to  meet  the  load  would 
be  too  small  for  use  in  practise.  For  alter- 
nating currents  the  resistance  of  a  steel 
cable  is  considerably  greater  than  for  di- 
rect current,  owing  to  the  skin  effect.  In 
copper  or  aluminum  conductors  the  lat- 
ter is  negligible,  increasing  the  resistance 
by  at  most  1  to  2  per  cent.,  but  at  high 
frequencies  the  apparent  resistance  of  steel 
conductors  may  be  increased  by  100  per 
cent,  or  more.  The  losses  may  be  kept 
within  moderate  limits  by  using  fine 
strands  to  act  as  laminations,  and  by  wind- 
ing the  spirals  of  alternate  layers  of  wire 
in  reverse  directions. 


300 


THE  ELECTRICAL  EXPERIMENTER 


September,  1917 


Spy  Aerials 


"S 


PY  wireless"  is  one  of  the  all- 
absorbing  topics  of  interest  thru- 
out  the  country  at  the  present 
time,  and  quite  naturally  it  would 
be,  for  some  of  the  reasons  which 
are  illustrated  and  described  herewith. 

The  average  law-abiding  citizen  will 
probably  consider  that  some  of  the  devices 
mentioned  would  not  serve  at  all  for  the 
reception  or  transmission  of  wireless  mes- 
sages, even. over  short  distances  of  five  to 
ten  miles,  but  such  is  the  case  as  experts 
well  know  from  many  experiments  and 
tests  which  have  been  conducted  in  the 
past  few  years. 

A  simple  and  extremely  innocent-looking 
flag-pole  aerial  might  be  constructed  by  a 
clever  spy  as  shown  in  Fig.  1.    This  is 
nothing  else  but  the  well-known  concen- 
trated  aerial   of  which 
much  has  been  publisht 
in  the  past  three  years.  ^ ^™ 
In   France  the  concen- 
trated   antenna  consist- 
ing of  a  small   rod  or 
tube,   a   few   meters  in 
length  and  wound  with 
a  layer  of  insulated  wire, 
has   proved   capable  of 
picking  up  wireless  mes- 
sages at  quite  consider- 
able distances  from  the 
Eiffel  Tower  Radio  Sta- 
tion at   Paris.     In  this 
country  several  very  sat- 
isfactory  experiments 
have   been   carried  out 
with  similar  aerials  consisting  of  a  large 
number  of  turns  of  wire  concentrated  in  a 
small    space,   notably  .  at   Union  College, 
Schenectady,  N.  Y.,  and  Atlantic  City,  N.  J. 

It  is  a  matter  of  actual  fact  that  these 
small  concentrated  aerials,  which  however 
possess  considerable  inductance,  tho  of 
very  small  dimensions,  have  picked  up 
messages  five  hundred  to  one  thousand 
miles  away.  In  fact,  it  is  believed  that  the 
Union  College  aerial,  which  did  not 
measure  over  ten  feet  square,  actually 
picked  up  messages  from  Nauen,  Germany, 
a  distance  of  nearly  four  thousand  miles. 
Several  modifications  of  the  flag-pole  an- 
tenna are  possible;  the  layer  of  wire  might 
be  covered  with  a  fiber  or  other  sheath 
painted  to  imitate  wood,  etc. 

Metal  roofs  may  often  be  used  to  ad- 
vantage in  receiving  wireless  messages,  and 
also  for  transmitting  them  over  short  dis- 
tances as  indicated  by  Fig.  2.  If  the  roof 
is  grounded  by  a  continuous  leader  pipe 
running  down  into  a  cistern  or  sewer,  then 
this  pipe  would  have  to  be  cut  or  patched 
up  in  some  way,  so  that  the  metal  roof 
would  be  insulated  by  the  framework  of  the 
building,  and  a  lead  wire  run  from  the  Toof 
or  leader  into  the  house. 

Electric  light  wiring  is  one  of  the  sim- 
plest indoor  aerials  which  could  be  used 
by  a  Spy.  It  would  usually  be  necessary  to 
open  the  service  switch  so  as  to  isolate  the 
house  wiring  system,  and  as  every  electri- 
cian knows,  these  wires  are  very  highly 
insulated  and  form  really  a  very  good  radio 
aerial,  in  view  of  this  excellent  insulation. 

Fig.  3  also  shows  another  form  of  secret 
aerial  which  might  be  employed  for  carry- 
ing on  nefarious  radio  intercourse  by  the 
Kaiser's  able  spies.  Many  houses  are  fitted 
with  metal  instead  of  wood  lath,  and  the 
perforated  steel  lath  plates  usually  overlap, 
presenting  quite  an  appreciable  capacity, 
especially  when  large  rooms  or  corridors 
are  considered. 

Another  interesting  and  possible  aerial 
which  might  be  imprest  for  service  in 
emergency  is  the  ordinary  gas  pipe  system 


as  illustrated  in  Fig.  4.  It  would  be  an  easy 
matter  for  an  enemy  radio  expert  to  dis- 
connect the  gas  pipe  at  the  meter  in  the 
cellar  of  the  building,  so  as  to  isolate  it, 
and  in  this  way  the  building  gas  pipe  sys- 
tem would  be  fairly  well  insulated  by  the 
wooden  framework,  and  would  serve  as  an 
antenna  for  the  reception  of  messages  or 
even  for  transmitting  them. 

Little  does  the  washerwoman  hanging  up 
clothes  on  an  iron-wire  clothes-line  stop  to 
think  that  that  very  clothes-line  might  be 
serving  as  a  medium  for  secret  radio-com- 
munication. Such  may  be  the  case  very 
easily  (see  Fig.  5),  and  there  have  been 
several  instances  already  where  wires  very 
much  resembling  clothes-lines  have  been 
discovered  on  roofs  of  buildings  which 
have  proven  to  be  disguised  wireless  an- 


In  preparing  this  article  we  have  endeavored  to  show  the  unsuspect- 
ing public  how  an  enemy  agent  may  either  send  or  receive  radio  mes- 
sages by  means  of  the  most  innocent  appearing  objects. 

The  Editors  thought  it  best  to  give  the  article  wide  publicity,  in  order 
that  patriotic  citizens  may  the  better  apprehend  possible  spies,  who  might 
be  using  secret  aerials  of  the  types  illustrated. 

The  article  is  intended  for  public  enlightenment,  as  well  as  for  the 
country's  safety. 


tennae.  One  of  these  aerials  in  a  large 
eastern  city  extended  for  several  blocks, 
and  was  easily  capable  of  picking  up  mes- 
sages from  such  powerful  stations  as  that 
at  Nauen,  Germany.  If  you  live  in  the 
city  (or  even  in  the  country)  and  have 
occasion  to  use  a  metal  clothes-line  of. any 
appreciable  size,  it  might  pay  you  to  closely 
scrutinize  the  supporting  framework  to 
see  whether  or  not  some  alien  enemy  has 
been  at  work  in  an  effort  to  use  it  for 
wireless  communication  purposes. 

Fig.  6  illustrates  two  devices  which  the 
enemy  might  employ  to  carry  on  wireless 
service  for  quite  a  considerable  distance. 
The  first  of  these  involves  the  use  of  a 
hidden  aerial  supported  inside  of  a  brick 
smoke-stack.  Such  an  aerial  might  easily 
be  quite  a  pretentious  affair,  comprising  a 
large  number  of  wire  strands.  Consider  for 
the  moment  also  that  there  are  thousands 
of  brick  chimneys  in  various  parts  of  the 
country  in  the  neighborhood  of  factories 
and  other  plants,  such  as  have  been  closed 
down,  and  who  would  want  to  gamble  for 
one  moment  that  such  a  stack — which  might 
have  a  height  of  two  hundred  feet,  as  many 
of  them  have — is  not  harboring  a  secret 
radio  aerial.  City  houses  too  can  easily 
harbor  good  aerials  in  their  chimneys  and 
these  will  work  irrespective  of  the  fact  that 
much  heat  goes  up  the  flue. 

Another  substitute  antenna  which  is  often 
available  on  factory  chimneys,  as  well  as 
on  private  houses,  is  the  lightning  rod, 
which  you  and  I  would  most  probably  pass 
by  unthinkingly  a  thousand  times,  and  yet 
that  very  lightning  rod  might  be  serving 
as  a  valuable  link  in  the  Teuton's  espionage 
system.  Of  course  the  lightning  rod  would 
have  to  be  cut  at  the  earth  so  as  to  insulate 
it  and  the  trick  is  done ;  and  come  to  think 
of  it,  we  have  seen  lightning  rod  instal- 
lations which  rambled  over  considerable 
areas,  especially  on  large  factories,  not  to 
mention  200  foot  and  250  foot  brick  chim- 
neys. Even  a  one-hundred-foot  aerial  for 
instance  is  a  mighty  good  one,  as  any  radio 
experimenter  will  tell  you. 


The  open  well  could  easily  be  used  es- 
pecially in  the  country  to  contain  a  radio 
aerial  in  a  similar  manner  to  that  described 
in  connection  with  chimneys.  A  clever 
Spy  might  even  bury  his  lead-in  wire  from 
the  apparatus  in  the  house,  and  simply 
connect  it  at  the  well  to  a  small  wire  cable, 
which  could  be  substituted  for  the  usual  in- 
nocent-looking well  rope,  fastening  a 
bucket  to  the  lower  end  of  the  cable  in 
the  regular  manner.  When  in  use  of  course 
the  bucket  would  have  to  be  out  of  the 
water  so  as  not  to  "ground"  the  steel 
cable.  When  this  is  cleverly  done,  we 
would  like  to  know  indeed  of  a  more  inno- 
cent-looking radio  antenna. 

Have  you  examined  your  shade  trees 
closely  this  summer?  Don't  be  surprised 
if  you  find  a  wire  cleverly  painted  to 
match  the  bark  on 
the  tree  and  leading 
^^^^mmmm^^  up  to  the  v  a  r  i  o  u  s 
branches.  It  is  readily 
possible  for  a  persistent 
member  of  the  enemy 
espionage  squad  to  thus 
rig  up  a  tree  aerial,  and 
it  is  not  necessary  to 
travel  very  far  to  find  a 
sufficiently  large  tree, 
which  would  serve  as  a 
framework  for  several 
hundred  feet  of  insu- 
lated  wire. 

Fig.  7  illustrates 
this  very  ingenious 
antenna.  In  many  instances  success  could 
be  attained  using  the  same  tree  as  an  aerial 
for  wireless  communications,  but  placing  no 
wire  in  the  tree  whatever.  General  G.  O. 
Squier,  Chief  Signal  Officer,  U.  S.  A., 
found  in  some  tests  made  several  years 
ago  that  it  is  readily  possible  to  receive 
wireless  messages  over  fair  distances  by 
simply  driving  a  nail  in  the  trunk  of  a 
tree,  and  thus  utilizing  the  tree  itself  and  its 
foliage  as  the  antenna.  This  works  sur- 
prisingly well. 

Not  to  be  outdone  by  all  of  the  foregoing 
more  or  less  efficient  emergency  aerials, 
wireless  experts  have  for  some  time  known 
that  radio  messages  could  be  picked  up  over 
remarkable  distances  by  properly  connect- 
ing a  radio  receiver  to  existing  telegraph 
or  telephone  lines  as  illustrated  at  Fig.  8. 
A  Spy  could  readily  use  a  pocket  wireless 
set  in  this  case,  and  chances  are,  he  would 
thrive  many  months  and  even  years  before 
being  detected,  as  naturally  he  would  not 
endeavor  to  carry  out  this  important  ex- 
periment in  the  front  parlor  with  the  shades 
up  and  the  lights  turned  on.  Quite  the 
contrary. 

In  Fig.  9,  we  see  two  other  forms  of 
aerials,  which  may  be  used  to  cover  quite 
respectable  distances,  either  transmitting  or 
receiving.  One  of  these  is  the  ordinary 
wire  fence,  which  may  be  found  most  any- 
where and  some  of  which  are  very  well 
insulated,  due  to  the  particular  construction 
employed,  and  the  other  possible  aerial 
here  shown  is  the  ordinary  iron  fence,  which 
very  often  is  mounted  on  stone  basepil- 
lars,.  so  that  it  would  be  quite  well  in- 
sulated. These  suggestions  may  sound  a 
little  out  of  place  to  a  great  many  per- 
sons, but  it  is  well  to  remember  that  several 
years  ago,  a  number  of  tests  carried  out 
in  New  York  City,  proved  that  wireless 
messages,  even  from  out  of  town  stations 
could  be  picked  up  very  easily  by  connect- 
ing a  wireless  receiving  set  to  an  ordinary 
iron  fire-escape  located  not  higher  than  the 
(Continued  on  page  342) 


September,  1917  THE  ELECTRICAL  EXPERIMENTER  30 


SECRET  RADIO  AERIALS' 


(See  descriptive  text  on  opposite  page.) 


302 


THE  ELECTRICAL  EXPERIMENTER 


September,  1917 


The  Marvels  of  Radio-Activity 


Properties  of  Radium  Rays 

THE  radiations  emitted  from  Radium 
are  of  three  distinct  types  known 
as  the  alpha,  beta  and  gamma  rays. 
Rutherford  showed,  in  1899,  that 
the  radiation  from  uranium  was 
complex  and  consisted  of  (1)  an  easily 
absorbed  radiation  stopt  by  a  sheet  of  paper 
or  a  few  centimeters  of  air,  the  alpha 
rays,  and  (2)  a  far-more  penetrating  ra- 
diation  capable   of   passing   thru  several 


Formation  of  the  Electrons  of  the  "Alpha"  Rays  from  a 
Particle  of  Radium.    Photographic  Picture  by  C.  T.  R.  Wilson. 
Magnified  1:2,  18. 


Alpha"  Rays  of  a  Radium  Particle  as  Above.  Highly  Magnified. 
The  Fracture  of  the  Rays  Is  Remarkable.  It  Is  Produced  by  Colli- 
f.  °J  the  A-corpuscles  with  Another  Atom.  The  Ingenious 
Method  of  Wilson  Is  Based  Upon  the  Electronic  Property  of  the 
Radium  Rays.  In  Water  Vapor  the  Electrons  Generate  Condensa- 
tion Droplets  of  Aqueous  Vapor. 

centimeters  of  aluminum,  the  beta  rays. 
Later  Villard  found  that  radium  emitted 
a  very  penetrating  type,  the  gamma  ray, 
capable  of  passing  thru  twenty  centimeters 
of  iron  and  several  of  lead. 

The  Alpha  Rays 

The  alpha  rays  are  the  most  character- 
istic and  important  of  the  three  forms  of 
radiation.  They  are  slightly  deflected  by 
an  intense  magnetic  field.  Some  idea  of 
the  intensity  may  be  gathered  from  the 
fact  that  a  field  which  will  deflect  cathode 
rays  (from  a  vacuum  tube)  in  a  circle 
of  0.1  cm.  radius  will  turn  alpha  rays  only 
in  a  circle  of  39  cm.  radius. 

Before  going  on  with  our  discussion 
of  the  types  of  rays,  it  would  be  well  to 


By  JEROME  S.  MARCUS,  B.Sc.    (Ch.  E.) 
Part  II. 

interpolate  an  experiment  on  their  ability 
to  affect  a  photographic  plate,  that  this 
phenomenon  may  be  used  later.  (Experi- 
ment— A  plate  is  well  wrapt  in  black  paper 
in  a  dark-room,  and  a  small  amount  of 
the  salt  secured — as  explained  in  the  last 
article — placed  on  top.  A  key  or  other  bit 
of  metal  may  be  placed  between  the  salt 
and  the  paper.  After  about  forty-eight 
hours  the  plate  is  developed.  In  all  these 
experiments  the  salt  used  may  be  kept  in 
a  glass  tube  if  care  is  taken 
to  secure  lead-free  glass,  as 
the  Jena  variety.  The  lead 
in  ordinary  glass  will  absorb 
a  considerable  number  of  the 
rays.  The  author  took  the 
radiograph  shown  in  thirty 
hours,  using  two  grams  of 
uranyl  chlorid  in  the  bottom 
of  a  Jena  beaker.) 

Becquerel  demonstrated  the 
magnetic  properties  of  the 
alpha  rays  by  placing  a  plate 
with  radioactive  salt  a  short 
distance  away  in  a  magnetic 
field.  The  plate  showed  a 
distinct  band  where  the  rays 
had  moved.  The  deflection 
is  greatly  magnified  in  a 
partial  vacuum. 

By  means  of  the  magnetic 
field  it  has  been  de- 
termined that  the 
alpha  ray  consists  of 
a  stream  of  positively 
electrified  particles. 
Hence,  they  will  be 
deflected  also  by  an 
electrostatic  field. 

Observations  of  the 
mass  and  velocity  of 
these  particles  have 
been  made  by  Ruther- 
ford, from  the  data 
secured  by  deflection. 
The  velocity  of  an  al- 
pha particle  is  2.5x10" 
cms.  per  second,  or 
approximately  15,000 
miles  per  second.  The 
mass  is  calculated 
from  physical  chemis- 
try as  twice  that  of 
the  hydrogen  atom. 

The  alpha  radiation 
is  intense,  but  the 
power  of  penetration 
by  the  rays  is  inde- 
pendent of  the  inten- 
sity. A  thickness  of 
medium  sufficient  to 
stop  any  one  particle 
will  stop  the  whole 
discharge  —  regardless 
of  its  strength.  That 
the  penetration  is  small  is  due  to  the  fact 
that  the  mass  of  an  alpha  particle  is  large. 

Due  to  the  large  mass,  the  alpha  par- 
ticle possesses  a  considerable  kinetic  energy 
(6xl0-6  ergs).  Owing  to  this  fact  the  par- 
ticle has  a  great  power  of  ionizing  gases. 
The  range  of  ionization  depends  on  the 
element  emitting  the  ray,  the  nature  and 
pressure  of  the  gas.  The  maximum  is 
about  seven  centimeters  of  air  at  atmos- 
pheric pressure. 

The  alpha  rays  do  not  possess  much 
power  of  affecting  a  photographic  plate, 
the  greater  part  of  the  effect  being  pro- 
duced by  the  beta  and  gamma  rays.  They 
do,  however,  exhibit  a  remarkable  power 
of    causing    fluorescence    in    many  sub- 


stances. A  little  instrument  devised  by 
Sir  William  Crookes,  known  as  the  spin- 
thariscope, shows  this  phenomenon  in  a 
very  pretty  and  visual  manner.  A  short 
brass  tube  has  a  screen  coated  with  crys- 
talline zinc  sulfid  at  one  end,  and  a  lens 


line  su/ph/de  scree/? 

k 


©  Lens 


Rod/i/m  so/f 


The  Marvels  of  Radio-activity  Are  Happily 
Available  to  Everyone  Interested,  In  the  In- 
strument Known  as  the  "Spinthariscope." 
The  Eye  Perceives  the  Radium  Particles 
Bombarding  the  Zinc  Sulfid  Screen,  the  Ac- 
tion Being  Magnified  by  a  Strong  Lens. 


that  can  be  focused  at  the  other.  A  small 
pointed  brass  needle,  having  an  extremely 
small  amount  of  radium  salt  mounted  on 
the  end,  is  fixt  a  few  millimeters  from 
the  screen.  The  screen  will  be  seen  to 
scintillate  at  points  where  the  alpha  rays 
strike,  the  beautiful  effects  having  been 
likened  to  "moonlight  on  rippling  water." 
(These  instruments  can  be  purchased  very 
cheaply.)  Each  flash  corresponds  to  the 
impact  of  an  alpha  particle  against  the 
screen.  This  is  possibly  the  only  direct 
evidence  of  the  action  of  one  individual 
atom  known  to  science. 

It  is  known  that  a  given  mass  of  ra- 
dium maintains  itself  at  a  temperature 
higher  than  that  of  the  surrounding  air. 
This  is  due  to  the  changing  of  the  kinetic 
energy  of  the  alpha  particles  into  heat. 
Professor  Curie  reached  the  conclusion 
that  one  gram  of  pure  radium  would 
emit  a  quantity  of  heat  equal  to  100  gram- 
calories  per  hour. 


ph. to  Radium  Limited 

Radium-therapy  Is  the  Newest  Agent  for 
Treating  Various  Ills.  This  Is  a  Practical 
Apparatus  for  the  Generation  of  Radium 
Emanation  Water.  The  Inner  Porcelain  Cell 
Contains  An  Insoluble  Radium  Salt,  Which 
Activates  the  Whole  Volume  of  Water  Daily. 


September,  1917 


THE  ELECTRICAL  EXPERIMENTER 


303 


The  Beta  Rays  The  gamma   rays   can  be  investigated 

The  beta  rays  are  composed  of  nega-  by  the  electrical  method  as  they  ionize 
tively  charged  particles.  They  are  con-  gases  they  pass  thru.  Rutherford  states 
sidered  by  many  as  electrons  with  an  ex-  that  the  gamma  radiation  from  30  milli- 
ceptionally  high  velocity,  1.6xl010  cms. 
per  second.  Beta  particles  are  de- 
flected by  magnetic  and  electrostatic 
fields  with  much  greater  ease  than 
the  alpha  particles.  The  deviation 
reduces  the  ionizing  power. 

The  ionizing  caused  by  the  beta  ra- 
diation is  considerable,  but  not  as 
marked  as  that  caused  by  the  alpha 
type.  However,  the  range  is  very 
much  longer. 

Owing  to  the  exceptionally  high 
velocity  of  the  beta  particles,  they 
have  a  considerable  power  of  pene- 
tration. The  absorption  effected  by 
matter  is  approximately  proportiona 
to  the  density  of  the  medium.  Thus 
lead  is  a  far  better  absorbent  thai 
aluminum.  (Experiment — A  charged 
electroscope  is  placed  on  one  side  ol 
a  thin  sheet  of  lead  and  the  salt  on 
the  other.  The  rate  of  collapse  of 
the  leaves  is  noted.  A  sheet  of  alu- 
minum of  the  same  thickness  is  then 
substituted  for  the  lead  and  the  rate 
of  collapse  again  noted,  and  a  com- 
parison made.) 

The  photographic  action  of  the  beta 
rays  is  intense,  as  proved  by  deviating  them     grams  of  radium  bromid  could  be  detected 
away  from  the  other  types,  and  allowing     by  the  electroscope  after  passing  thru  30 
them  to  act  on  a  plate.    A  brilliant  fluores-     centimeters  of  solid  iron ! 

The  photo- 
graphic action  of 
the  rays  is  also 
very  intense,  and 
most  of  the  ac- 
tion produced  by 
any  radioactive 
substance  seems 
to  be  due  to  the 
gamma  radiation 
emitted.  Fluor- 
escent effects  are 
produced  by  the 
gamma  rays  to  a 
marked  extent  in 
a  wide  variety  of 
materials,  altho 
there  are  cases 
where  the  action 
differs  from  that 
of  X-rays. 

Experiment 
shows    that  the 

Prepared  specially  for  the  "E.  E."  by  Radium  Chemical  Ltd       abSOTptlOn  of 

Curve  Showing  the  Decay  of  Radium.    Each  Radio-active  Element  Trans-  gamma  rays  de- 
mutes  at  a  Constant  Rate  That  Is  Characteristic  for  That  Element.  Radium  pends  on  the  den- 
Is  Disintegrating  at  Such  a  Rate  That  Half  of  Any  Quantity  Will  Have     •.        t  ^ 
Transformed  in  1,690  Years.    After  a  Second  Interval  of  1,690  Years  Half  ul    ul.c  "if 
of  the  Remaining  Radium  Will  Be  Gone,  and  So  On  Until  After  Ten  Times  aium,   as   in  tne 
the  Half-decay  Time  Has  Elapsed,  16,900  Years,  There  Will  Be  Remain-  case  of  the  beta 
ig  Only  0.1%  of  the  Original  Amount  of  Radium.    The  Curve  Shows  This  r_  j-  +-  _  p>llf 
Graphically.    By  Substituting  the  Half-decay  Time  of  Any  Other  Radio-  radiation,  dui  as- 
Element,  the  Curve  Can  Serve  to  Show  Its  Rate  of  Decay.    Thus  for  suming  the  gam- 
Radium  Emanation  3.85  Days  Is  the  Half-decay  Period,  and  So  In  38.5  ma  rays  to  be  a 
Days,  Any  Quantity  of  This  Substance  Falls  to  0.1%  of  the  Initial  Amount.  varjetv   0f  ether 

disturbance,  it 


ondary  radiation  on  passing  thru  matter. 
A  pencil  of  beta  rays  falling  on  matter  is 
widely  scattered  in  all  directions,  the  scat- 
tered radiation  being  known  as  the  second- 


100Z 


so 


60 


40 


20 


0 

leors 


1690 

* 

% 

6/60 

IS2/0 

Photo  Courtesy  Cold  Light  Mfg.  Co 

Here  the  Radium  Is  Measured  by  Means  of  An  Electroscope;   Employees  from   Other   Parts  of  the 
Laboratory  Are  Excluded  at  All  Times,  as  the  Electroscope  Is  So  Sensitive  That  Even  the  Radium 
Infection  in  Their  Clothing  Impairs  Its  Accuracy.    (Electroscope  in  the  Middle  Foreground.) 

ary  beta  rays.  The  gamma  rays  give  rise 
to  secondary  rays  which  consist  in  part  of 
scattered  gamma  rays,  and  in  part  of  elec- 
trons moving  with  a  high  velocity.  These 
secondary  rays  produce  tertiary  rays,  and 
so  on. 

The  impact  of  the  alpha  rays  on  matter 
sets  free  a  number  of  slow-moving  elec- 
trons which  are  very  easily  affected  by  a 
magnetic  or  electro-static  field.  This  type 
of  radiation  was  first  observed  by  Thom- 
son, and  has  been  called  by  him  the  S  rays. 

The  angle  of  incidence  of  the  primary 
rays  affects  the  intensity  of  the  secondary 
radiation.  The  most  effective  angle  ap- 
pears to  be  about  45°. 

{Continued  on  page  355) 


cence  is  caused  in  many  substances,  but 
not  the  scintillation  of  the  alpha  rays. 

The  mechanical  disintegration  caused  in 
many  substances,  appears  *  largely  due  to 
beta  rays.  Paper  and  rubber,  after  hav- 
ing been  wrapt  around  relatively  large 
quantities  of  highly  active  compounds,  be- 
come quite  rotten.  Chemical  changes  are 
also  produced,  or  induced,  in  many  stable 
compounds.  The  harmful  physiological 
effects,  as  the  Becquerel  burns,  are  attribut- 
able to  these  electronic  rays. 

The  Gamma  Rays 

The  third  type  of  radiation  has  an  al- 
most incredible  power  to  penetrate  matter. 
The  gamma  rays  appear  to  be  similar  to 
X-rays,  being  ether  pulses,  but  are  en- 
dowed with  very  considerably  greater 
power  of  penetration  than  even  the  most 
penetrating  variety  of  X-ravs. 


seems  impossible  to  assign  a  limit  to  their 
theoretical  penetration.  Yet  a  certain 
thickness  of  a  medium  will  serve  to  ab- 
sorb them. 

Gamma  rays  are  not  affected  by  a  mag- 
netic field  and  so  cannot  be  charged  par- 
ticles, as  are  the  other  two  types. 

Occurrence 

The  alpha  rays  are  found  in  the  radi- 
ation of  all  radio-active  bodies.  Beta  rays 
are  emitted  by  radium,  uranium,  thorium 
and  actinium,  but  not  by  polonium.  Gamma 
rays  being,  according  to  some  theories,  a 
consequence  of  beta  rays,  are  given  out 
by  actinium,  thorium,  uranium  and  radium. 
In  all  cases,  the  radiation  from  radium  is 
stronger  than  the  others. 

Secondary  Rays 

The  three  types  of  ray  all  set  up  sec- 


2* 

taw 

Photo  Courtesy  Cold  Light  Mfg.  Go. 

Luminous  Radium  Paint  Is  Being  Widely 
Applied  Now  to  Switch  Buttons,  Lamp  Pen- 
dants, Dials,  Etc.  At  Right,  Appearance  In 
Dark  of  Radium  Coated  Pendant  and  Switch; 
Left,  Daytime  Appearance.  The  First  Radi- 
um Luminous  Mixtures  Were  Made  In  1902 
by  Wm.  J.  Hammer,  the  Eminent  American 
Electrical  Engineer,  Which  Fact  Is  Proved 
In  His  Letters  Patent. 


304 


THE  ELECTRICAL  EXPERIMENTER 


September,  1917 


LARGEST  ELECTRIC  LOCOMO- 
TIVE DEVELOPS  7,000  H.  P. 

A  new  era  in  railroad  practise  is  dawn- 
ing.    The  problem   now   confronting  the 


pearance  to  a  regulation  steam  locomotive. 

The  engine  may  be  operated  from  either 
end,  and  the  control  system  has  been  de- 
signed  so  that  the  application  of  power 


tion  will  greatly  facilitate  the  movement 
over  this  grade  section.  Trains  of  maximum 
tonnage  will  be  handled  by  two  of  these  en- 
gines, one  pulling  and  one  pushing,  at  a 
speed  of  over  twenty  miles  an  hour,  that 
now  require  three  and  sometimes  four 
steam  locomotives  of  the  largest  size,  and 
at  only  about  one-half  the  speed  that  will 
be  attained  by  the  electrics. 

Notwithstanding  the  power  of  these 
giants  of  the  rail,  they  are  operated  by 
one  engineer  with  perfect  ease,  owing  to 
the  design  of  the  control  apparatus. 


This  Electric  Locomotive  Is  "King 
of  the  Rail,"  Measures  76  Feet  in 
Length  and  Develops  7000  Horse- 
power. Equal  to  Two  Giant 
Steam  "Locos"  It  Will  Haul 
Freight  Trains  Over  the  Allegheny 
Mountains  At  Twice  the  Speed  of 
Its  Predecessors. 


railroads  is  that  of  increasing 
their  efficiency,  of  getting  more 
but  of  their  existing  equipment 
of  trackage.  Their  product, 
namely  transportation,  is  re- 
stricted by  congestion  and  made 
more  expensive  by  increased 
costs  of  fuel,  materials  and  la- 
bor. 

Accordingly  they  have  turned  'j" 
to  electrification  as  a  solution  of 
the  problem  thru  the  applica- 
tion of  higher  powered  engines  to  their 
trains.  Greater  saving  is  also  secured 
thru  the  more  efficient  use  of  coal  in  the 
great  steam  turbine  plants,  and  also  from 
the  huge  water  power  plants. 

Pursuing  a  far-seeing  policy,  which  was 
clearly  exemplified  some  years  ago  when 
it  built  the  first  steel  passenger  car,  the 
Pennsylvania  Railroad  has  recently  had 
built  the  electric  freight  locomotive  shown, 
which  is  the  first  of  what  will  be  a  stand- 
ard type  of  high-powered  units  to  be  used 
by  the  railroad  for  moving  its  freight  traf- 
fic. This  locomotive,  which  is  the  most 
powerful  ever  built,  weighs  260  tons,  is 
76  feet  long,  and  is  capable  of  developing 
a  maximum  of  7,000  horsepower! 

This  monster  of  the  rails,  capable  of 
exerting  as  much  power  as  a  string  of 
trolley  cars  over  a  half-mile  long,  draws 
its  current  from  a  wire  no  bigger  than  a 
lead  pencil.  This  is  made  possible  by  the 
use  of  the  high  voltage,  single  phase,  alter- 
nating-current distribution  system.  Cur- 
rent is  supplied  from  a  single  trolley  wire 
at '11,000  volts  and  the  track  is  used  for 
the  return  circuit  just  as  in  the  case  of 
the  ordinary  city  trolley  car.  This  cur- 
rent is  changed  by  means  of  suitable  auxil- 
iary devices  on  the  locomotive  to  a  form 
suitable  for  application  to  the  four  three- 
phase  induction  motors,  two  of  which  are 
mounted  on  each  of  the  locomotive  trucks. 
These  motors  possess  characteristics 
which  particularly  adapt  them  to  this  work, 
namely,  ruggedness,  constant  speed  and 
powerful  starting  effort. 

The  locomotive  is  built  in  one  unit  con- 
sisting of  a  cab,  and  trucks  each  having 
six  driving  wheels,  six  feet  in  diameter. 
Dn  each  truck  there  are  mounted  two 
powerful  motors,  geared  to  a  spring  gear 
jackshaft,  which  in  turn  is  connected  to 
the  driving  wheels  by  side  rods  in  a  man- 
ner very  similar  in  construction  and  ap- 


is so  gradual  that  a  long  train  may  be 
started  without  a  jerk. 

A  maximum  speed  of  slightly  over  20 
miles  an  hour  can  be  obtained  by  this  loco- 
motive with  a  heavy  train  on  grade,  a  speed 
that  is  deemed  sufficient  in  view  of  the 
heavy  traffic,  sharp  curves  and  steep  grades 
to  be  encountered.  A  speed  of  10  miles 
an  hour  can 
also  be  obtained 
when  desired 
for  slow  move- 
ments, such  as 
switching  and 
running  about 
the  yards. 

This  engine  is 
primarily  i  n  - 
tended  "for  use 
in  hauling 
the  tremendous- 
ly heavy  traf- 
fic on  the  Penn- 
sylvania Rail- 
road over  the 
Allegheny 
Mountains  be- 
tween Altoona 
and  Johnstown, 
Pa.,  including 
the  famous 
H  o  r  seshoe 
Curve,  a  dis- 
tance of  about 
forty  miles. 
The  freight 
traffic  over  this 
section  is  un- 
usually heavy, 
amounting  to 
as  much  as  300,- 
000  tons  a  day. 
The  grades  are 
unusually  steep, 
and  electrifica- 


HONK!  HONK!  HERE  COMES  THE 
MOTOR  CHAIR. 

One  of  the  chief  attractions  at  the  re- 
cent San  Francisco  Exposition  and  at  other 
similar  fetes  thruout  the  country,  as  well 
as  at  the  seaside  resorts,  is  the 
electric  motor  chair,    one  of 
which  is  here  illustrated. 

An  electric-motor  chair  fur- 
nished with  either  150  amp.-hr. 
or  200  amp.-hr.  batteries  is  the 
latest  luxury.  The  150-amp.- 
hr.  battery  when  fully  charged 
will  give  five  hours  of  contin- 
uous running  service,  it  is  said, 
and  the  200-ampere-hour  bat- 
tery will  give  seven  hours. 
The  batteries  are  of  the  12- 
volt  type  and  the  motor  is  de- 
signed to  develop  0.5  hp.  to  2 
hp.,  according  to  load.  The 
motor  is  geared  directly  to  the 
axle  of  the  front  wheel  with  a 
triple  worm  which  permits  the 
motor  to  propel  the  car  up  a 
15  per  cent  grade  when  loaded 
with  two  adults.  Extending  in 
front  of  the  car  is  a  guard 
which  breaks  the  circuit  be- 
tween the  batteries  and  motor 
and  applies  the  brake  when  it 
comes  in  contact  with  any  obstacle. 


Electrically  illuminated  signs  to  be  car- 
ried on  the  roofs  to  show  whether  taxicabs 
are  vacant  or  occupied  have  been  patented 
in  England.  Why  not  invent  an  electric 
sign  giving  the  rates  to  various  points? 
We  never  could  savvy  taximeter  jargon. 


Honk!  Honk!  Watch  Your  Step.    Here  Comes  the  Motor  Chair.  It 
Is  Particularly  Adapted  to  Ladies'  Use  and  Will  Not  Bite,  Balk  or 
Rear.    Can  Be  Stopt  Instantly  and  Is  Both  Clean  and  Noiseless. 


September,  1917 


THE  ELECTRICAL  EXPERIMENTER 


305 


BIRD'S  NEST  IN  ARC  LAMP. 

Recently  an  employee  of  the  Cincinnati, 
Ohio,  Electric  Company,  found  that  Eng- 
lish sparrows  had  built  a  nest  in  an  arc 
lamp.  The  top  of  the  lamp  had  been 
broken  so  that 
the  birds  found  a 
warm  place  for  a 
home.  Evidently 
the  nest  which 
they  built  was  oc- 
cupied thru  most 
of  the  winter. 
The  birds  picked 
the  wires  and 
this  interfered 
with,  but  did  not 
stop  the  illumina- 
tion. Attention 
was  thus  called 
to  the  lamp,  and 
i  n  v  e  s  tigation 
showed  the  pres- 
ence of  the  nest, 
which  had  been 
built  so  as  to  fill 
part  of  the  in- 
terior. The  birds 
had  not  been 
harmed  by  their 
experience.  Pho- 
to courtesy  C. 
G.  Stander. 


AUTO  CUTS 
OFF  TELE- 
PHONE 
POLE. 

At  Logan,  W. 
Va.,  recently  an 
automobile 
The   Birds  In   Cincinnati  crashed    into  a 
Are   Strictly   Up-to-date,  telephone  pole 
This    Nest    In    An    Arc  carrying  a  heavy 
Lamp  Proves  It.  joad       Jhe  car 

struck  the  pole 
with  such  force  that  a  20-foot  section  was 
broken  out  of  the  pole  just  above  the 
ground  line.    This  part  of  the  pole  fell 


A  Peculiar  Accident  In  Which  a  Telephone 
Pole   Was   Severed    By   An   Auto  Crashing 
Into  It.    The  Pole  Remained  Suspended  by 
Its  Own  Wires. 

across  the  top  of  the  car  and  remained 
securely  balanced  there,  as  the  illustration 
shows.    The  upper  10-foot  section  of  the 


pole,  relieved  of  its  former  support,  dropt 
down  and  alighted  squarely  upon  a  steel 
messenger  wire  which  was  strung  above 
the  street  at  a  less  height.  There  the  piece 
of  pole  remained  in  an  upright  po- 
sition. Photograph  courtesy  C.  W.  de 
Forest. 


FREES      JUNGLES  OF 
TERRORS  FOR  EX- 
PLORER. 

Radio-telegraphy  has  shat- 
tered the  silence  and  terror  of 
the  jungle  for  explorers,  and 
it  is  possible  to  penetrate  vast 
wildernesses  now  without  once 
losing  touch  with  civilization. 
This  is  the  message  that  Dr. 
Alexander  Hamilton  Rice,  the 
explorer,  brought  with  him 
from  his  perilous  journey  2,100 
miles  up  the  Amazon  River. 
He  was  accompanied  on  his 
journey  by  his  courageous  wife 
and  a  party  of  scientists. 

In  speaking  of  his  explora- 
tions, Doctor  Rice  said : 

"We  took  the  Alberto,  a 
yacht  drawing  seventeen  feet, 
up  the  Amazon  to  Iquitos,  a 
distance  of  2,100  miles.  Com- 
modore Benedict  last  year  took 
the  Oneida  up  to  Manaos,  but 
we  went  1,000  miles  further, 
and  I  think  the  Alberta  is  the 
first  yacht  that  ever  went  as 
far  as  Iquitos. 

"It  was  while  we  were  off 
Iquitos  that  we  realized  the 
possibilities  of  the  wireless.  At  that  re- 
mote point  we  had  no  difficulty  in  picking 
up  the  signals  sent  out  from  the  Arlington 
Station  at  Washington.  They  came  to  us 
sharp  and  crisp,  and  it  made  us  feel  sort 
of  homelike  to  think  that  we  were  in  touch 
with  the  outside  world  in  spite  of  the  fact 
that  we  had  penetrated  thousands  of  miles 
of  this  vast  country. 

"We,  of  course,  were  not  the  first  explor- 
ers of  the  Rio  Negro,  which  we  reached. 
Others,  notably  Dr.  Russell  Wallace,  in  1851, 
went  up  the  river,  but  Doctor  Wallace  did 
not  succeed  in  making  the  latitude  and  lon- 
gitude observations  on  the  north  bank, 
which  we  accomplisht. 

"Another  purpose  was  the  further  test- 
ing of  the  portable  wireless  which  had  been 
especially  made  for  this  journey,  and  a 
third  object  was  the  study  of  the  diseases 
of  the  Rio  Negro  Valley. 

"As  its  name  indicates,  the  Rio  Negro  is 
a  black  water  river,  and  it  is  unusually 
free  from  the  logs,  driftwood  and  debris. 
White  water  rivers  like  the  Amazon,  in  this 
region,  are  just  the  reverse,  being  full  of 
floating  matter.  Then  again  the  white 
water  rivers  have  the  usual  vegetation  ex- 
tending back  from  their  banks  into  the  for- 
est, but  with  the  Rio  Negro  the  vegeta- 
tion varies  and  has  no  set  law  of  con- 
sistency. 

"After  you  leave  Santa  Isabel  you  come  to 
the  Caoxeiras  rapids  and  cataracts,  which 
are  formed  by  ledges  and  rocks." 


satisfy  a  passing  mood  of  the  housewife. 
This  has  never  been  possible  heretofore  in 
metal  and  glassware  fixtures  than  have 
been  installed  permanently. 

The  secret  of  the  changeability  of  these 
new  fixtures  consists  in  their  unique  con- 
struction, which  embodies  two  separate 
glass  bowls  held  together  by  means  of  a 
metal  ring  and  so  arranged  that  between 


On  a  Recent  2,100- Mile  Journey  Up  the  Amazon  River 
in  South  America,  a  Noted  Explorer  Found  His  Radio 
Apparatus  of  Wonderful  Value.  The  Arlington  "Time 
Signals"  Were  Received  Daily  As  Well  As  Other  News. 


them  can  be  inserted  a  piece  of  colored 
silk  or  cretonne.  By  changing  this  insert 
it  is  thus  readily  possible  to  change  the  en- 
tire decorative  effect  of  the  fixture.  These 
fixtures  are  made  in  some  half  dozen  dif- 
ferent sizes  and  shapes,  some  having  shal- 
low, others  deep  bowls  and  some  urn- 
shaped  bowls.  A  pattern  is  furnished  with 
each  size  and  type  of  fixture.  This  per- 
mits cutting  the  fabric  to  exactly  the  right 
shape  and  size.  The  fixture  is  very  easily 
assembled  and  any  housewife  can  readily 
take  it  apart  and  change  it  as  she  wishes. 


A  CHANGEABLE  DECORATIVE 
LIGHT  SHADE. 

The  increasing  desire  of  the  modern 
housewife  for  artistic  decorative  effects  in 
her  home  is  bringing  about  the  develop- 
ment of  home  furnishings  of  all  kinds  that 
readily  adapt  themselves  to  varied  tastes 
and  designs  of  home  decorations.  The 
most  striking  feature  about  these  fixtures 
is  that  their  design  can  readily  be  changed 
from  time  to  time  to  suit  an  entirely  new 
type  of  interior  decoration,  any  special 
party  or  other  social  function,  or  even  to 


^^^^^^^ 

When    Madame    Tires    of    the  Same 
Lighting    Fixture    She    May    Insert  a 
New  Piece  of  Flowered  Silk  or  Other 
Material  in  This  New  Shade  and  Re- 
alize Her  Heart's  Desire. 

The  fabric  is  first  placed  over  the  inner 
bowl,  after  the  latter  is  inverted  on  a  table. 
This  bowl  has  prismatic  ribs  upon  it  which 
serve  to  reflect  most  of  the  light  upward 
toward  the  ceiling,  thus  making  the  fixture 
a  purely  semi-indirect  type. 


306 


THE  ELECTRICAL  EXPERIMENTER 


September,  1917 


THE  KISS  OF  DEATH. 

Contrary  to  expectation,  this  is  not  the 
title  of  a  new  film  thriller,  but  the  story  of 
a  short-circuit  on  a  13,800-volt  line.  On  a 
recent  Sunday,  trouble  showed  on  the  Fay- 
ville  line  between  Hopkinton  and  the  Sud- 
bury dam  in  England.  On  patrolling  the 
line  thru  the  woods  Charlie  Marshall,  Hop- 
kinton trouble  man,  found  one  of  the  lines 
on  the  ground  with  a  squirrel  lying  dead 


The  Destruction  of  Steel  and  Concrete  by  Electrolysis. 


By  K.  M.  COGGESHALL 


0 


When  These  Squirrels  Touched  Noses  There  Was  a  Flash 
of  Sparks  and  Two  Red-skins  Bit  the  Dust. 


beside  the  wire.  Another  squirrel  was 
wedged  in  the  cross-arm  brace  on  the  pole, 
and  was  also  dead.  On  examination  it  was 
found  that  the  bodies  and  noses  of  both 
animals  were  burned.  The  nature  of  the 
burns  disclosed  the  fact  that  one  squirrel 
was  on  the  line  and  the  other  was  on  the 
brace,  which  is  grounded.  When  the  little 
animals  touched  noses  a  flash-over  from 
line  to  arm  was  caused,  which  burned  off 
the  wire  and  resulted  fatally  for  the  unfor- 
tunate lovers.  Which  goes  to  show  that  the 
top  of  a  pole  carrying  13,800  volts  is  a  bad 
place  for  spooning. 


MAKING  "MALLO  TOPPING"  BY 
MOTOR. 

Mallo  topping— that  delicacy  which  we 

all  enjoy  so  much  at  soda  fountains — is 
now  made  by  motor. 

Place  one-half  gallon  of  Mallo  Topping 
in  the  whipper,  and  add  four  ounces  of 
hot  water,  says  the  recipe.  Start  the  ma- 
chine and  whip  two  or  three  minutes. 
Then  add  four  ounces  more  of  hot  water. 
Whip  this  until  nice  and  light.  The  Mallo 
Topping  when  finished  will  be  about  the 
consistency  of  whipt  cream.  By  whip- 
ping the  Mallo  Topping  with  this  amount 
of  water,  it  will  double  in  volume.    If  you 


Mallo  Topping  for  Soda  Water  Fountains  Can  Be 
Made  in  a  Jiffy  with  this  Motor-driven  Whipper. 


■wish  to  re-flavor  or  re-color  it,  place  the 
flavor  or  color  desired  in  the  mallo  when 
lit  is  being  whipt  up. 


(JITE  often,  while  walking  down  a 
city  street,  we  will  notice  a  little 
squad  of  workmen  digging  in  the 
roadway  to  unearth  a  burst  water 
main.  Perhaps  we  will  see  a  piece 
of  the  old  pipe  after  it  has  been  removed 
and  will  be  surprised  to  note 
how  it  is  pitted  and  eaten 
away.    If  a  pocket  knife  is 
used  to  dig  into  the  sides  of 
the  pipe,  it  will  be  found  to 
be  soft  and  easily  cut.  A 
chemist  would   tell   us  that 
this  destruction  of  the  steel 
or  cast  iron  pipe  was  caused 
by  electrolysis — a  decomposi- 
tion by  an  electric  current. 

A  further  explanation 
might  make  this  action  more 
lucid  if  we  consider  the  elec- 
tro-chemistry of  the  plating 
bath.  Here  we  have  the  cur- 
rent entering  the  bath  thru 
the  copper,  silver,  or  nickel 
metal,  passing  thru  the  bath, 
and  leaving  by  the  metal 
article  being  plated.  A  chemi- 
cal reaction  then  takes  place ; 
the  copper,  silver,  or  nickel, 
as  the  case  may  be,  is  de- 
composed and  a  deposit  of 
this  same  metal  is  formed 
on  the  object  being  plated.  The  voltage 
necessary  to  create  this  action  may  be  quite 
small  altho  the  decomposition  will  increase 
materially  with  a 
larger  difference  of 
potential. 

Dry  soil  does  not 
easily  lend  itself  to  the 
passage  of  an  electric 
current  altho,  espe- 
cially in  large  cities,  it 
contains  a  great  deal 
of  mineral  matter  and 
salts.  When  the  earth 
is  wet,  however,  these 
salts  dissolve,  thus 
changing  the  soil  into 
an  electrolytic  conduc- 
tor. It  can  easily  be 
seen,  then,  that  if  there 
is  a  difference  of  po- 
tential between  two 
points  on  the  earth's 
surface,   a  current  of 

electricity  will  flow  from  one  to  the  other. 

Most  cities  operate  a  street  railway  sys- 
tem which  uses  the  rails  as  a  return  circuit. 
As  it  is  impossible  to  insulate  the  rails 
from  the  ground,  the  current  will  stray 
from  them  and  flow  back  to  the  power 
house  thru  the  soil.  If  a  water 
main  is  in  the  near  vicinity  of 
these  currents  it  will  serve  as  a 
conductor  for  part  of  the  distance 
until  a  path  of  less  resistance  pre- 
sents itself.  Here,  then,  is  where 
a  problem  must  be  solved  by  the 
municipal  and  railway  engineers. 
At  every  point  along  the  water 
main,  where  the  electric  current 
leaves  the  pipe,  decomposition  by 
electrolysis  will  occur. 

Eventually  this  decomposition 
will  destroy  the  walls  of  the  pipe 
and  bursting  may  take  place  at  a 
critical  moment  when  an  excess 
pressure  is  put  upon  it  during  a 
fire. 

The  sketch  shows  the  condition 
contributing  to  electrolysis.  The 
current  flows  along  the  trolley,  thru  the 
car  motors,  to  the  rails,  and  back  to  the 
power  house.    Suppose  that  a  water  main 


runs  parallel  to  the  track.  Some  of  the 
current  will  stray  from  the  track,  as  in- 
dicated by  the  arrows,  and  use  the  water 
main  as  a  conductor.  At  the  point  of 
exit  near  the  power  house  electrolysis  will 
occur. 

Quite  often  there  will  be  a  high  resist- 
ance joint  in  the  water  pipe  caused  by  a 
coating  of  asphalt  or  other  compound.  In 
such  instances  the  electric  current  will  shunt 
around  this  joint  thru  the  soil.  Here, 
again,  we  find  electrolytic  action  where  the 
current  leaves  the  pipe.  This  disintegra- 
tion, as  a  rule,  causes  pittings  close  to  the 
lead  filler,  which  softens,  resulting  in  a 
leak. 

It  is  interesting  to  note  the  effect  electro- 
lysis has  on  different  metals.  The  cast  iron 
pipe  does  not  show  the  destructive  action 
on  its  surface  while  in  the  ground.  If  a 
section  of  the  pipe  is  removed,  however, 
and  exposed  to  the  sun's  rays  until  thoroly 
dry,  the  graphite  and  other  impurities  with 
which  the  pittings  are  filled,  become  hard 
and  drop  out  or  may  be  easily  removed  with 
a  pen  knife.  In  wrought  iron  and  steel 
pipes  the  iron  oxid  resulting  from  the 
chemical  action  is  diffused  thru  the  soil. 
As  a  rule  in  wrought  iron  pipes  the  action 
will  concentrate  at  one  point,  thus  causing 
rapid  deteriorization.  White  and  yellow 
salts  are  formed  when  electrolysis  takes 
place  in  lead  pipes.  This  is  especially  no- 
ticeable where  lead-sheathed  cables  are  used 
in  underground  wiring. 


Where  e/ectro/yrts  ' 


Wafer  mo/ti 


Grass  sec/w/ta, 


Diagram   Showing    How  the   Street    Railway   Current  Often 
Strays  from  the  Rails  to  a  Water  Pipe,  Eventually  Causing  a 
Ruptured  Main  Where  the  Current  Leaves  the  Pipe  Line. 

Many  experiments  have  shown  that  con- 
crete when  damp  is  a  good  conductor  of 
electricity.  The  majority  of  the  concrete 
structures  of  to-day  are  reinforced  with 
steel  bars.  It  has  been  found  that  when 
currents  of  electricity  pass  from  these  bars 
into  the  concrete,  the  latter  will  crack.  The 
oxids  of  iron  formed  occupy  a  space 
greater  than  the  original  bar  and  a  terrific 
outward  pressure  is  produced.  It  has  also 
been  found  that  when  currents  pass  from 
the  concrete  into  the  iron,  the  former  will 
soften  and  eventually  the"  rigid  bond  be- 
tween the  two  will  be  broken.  Electrolysis 
in  concrete  is  often  found  in  bridges  and 
where  steel  foundations  are  imbedded  in 
concrete. 

All  of  the  foregoing  discussion  refers 
only  to  the  action  of  direct  currents  such  as 
used  for  street  railway  power.  The  dam- 
age caused  by  alternating  current  is  so 
slight  as  to  be  negligible.  The  only  dif- 
ference is  that  while  with  direct  current 
electrolytic  decomposition  occurs  only  at 
the  positive  electrode,  with  alternating  cur- 
rent this  corrosion  is  present  at  both  elec- 
trodes. 


September,  1917 


THE  ELECTRICAL  EXPERIMENTER 


307 


NEW  LIFE  BELT  HAS  ELECTRIC 
LIGHT. 

The  illustration  herewith  shows  a  new 
wrinkle  in  life  belts,  and  one  which  should 
be  conducive  to  the  saving  of  many  lives 
annually.  It  often  happens  that  persons 
washed  overboard,  even  tho  provided  with 
a  life  belt,  are  lost  nevertheless,  particu- 
larly when  this  occurs  in  the  night  time. 


mention  the  perpetually  busy  servant  girl 
or  cook  who,  when  she  is  not  busy  frying 
potatoes  or  baking  cakes,  or  perusing  one 
of  Laura  Lean  Jibby's  famous  works,  is 
highly  preoccupied  with  the  fatuous  and 
propitious  duty  of  entertaining  the  iceman. 


A  Yankee  Genius  Has  Come  Forward  With 
Light   Attachment   for    Life    Belts,  Which 
Should  Help  to  Save  Many  Lives  Ann 


To  increase  the  chances  of  being  rescued 
of  the  person  so  situated,  a  New  York  in- 
ventor, Mr.  A.  M.  McGiff,  has  patented  a 
luminous  life  belt. 

As  soon  as  the  person  dons  this  life  belt 
a  switch  is  closed  which  illuminates  the 
electric  light  or  lights,  and  thus  the  ship- 
wrecked soul  has  every  chance  of  being 
seen  by  another  vessel  in  the  dark.  The 
lamps  may  be  supplied  with  current  from 
a  dry  or  storage  battery  placed  within  one 
of  the  belt  compartments. 


MOVING    MAGNET  OPERATES 
MYSTIC  WINDOW  DISPLAY. 

Possibly  you  have  found 
yourself  among  a  hundred 
others  standing  before  an  at- 
tractive show  window,  and 
patiently  stretching  your  neck 
in  an  effort  to  see  what  held 
the  interest  of  the  crowd. 
Mysticism  is  the  key  to  nearly 
all  of  the  best  window  attrac- 
tions that  have  been  evolved  in 
the  past  several*  years.  The 
one  shown  here- 
with is  no  excep- 
tion, and  undoubt- 
edly you  have 
come  face  to  face 
with  it  more  than 
once  without  being 
able  to  figure  out 
just  what  caused 
the  ever  shuffling 
advertisement  to 
move  about  in  such 
an  uncanny  man- 
ner. 

The  display  in 
question  is  gen- 
erally designed 
with  a  heavy  plate 
glass  top  sup- 
ported on  four  well-spaced  columns.  When 
you  see  this  device  in  operation,  it  is  really 
very  puzzling,  for  it  is  hard  for  one  to 
conceive  that  a  magnet  could  be  made  pow- 
erful enough  to  move  the  advertisement 
card  and  its  attached  base  about  on  the 
glass  plate,  which  latter  stalls  most  of  the 
"electrical  experts"  in  the  crowd,  as  glass 
is  known  to  be  a  good  electrical  insulator.  A 
magnet  is  really  in  back  of  or  rather  under 


all  be  eliminated,  and  the  time  re- 
quired reduced  to  a  minimum  by  the  use 
of  the  motor-operated  opener  shown.  This 
device  opens  the  letters  in  a  continuous 
stream,  cutting  only  a  thread  from  the  edge 
of  the  envelopes,  and  in  a  seemingly  un- 
canny way  missing  the  enclosures.  One 
of  these  letter  openers  in  actual  operation 
has  opened  73,000  letters  in  a.  working  day 
of  8  hours ! 

In  operation,  the  unopened  letters  are 
placed  on  a  feed-table  back  of  a  guard, 
which  has  a  capacity  of  50  letters  at  a 
time.  They  are  fed  thru  one  at  a  time 
by  means  of  two  rubber  rollers,  which  pass 
them  along  past  two  cutting  wheels.  The 
guard  eliminates  all  possibility  of  the  oper- 
ator's fingers  coming  into  contact  with  the 
cutters.  The  depth  of  the  cut  may  be 
varied  and  set  at  will.    After  the  letters 


An  Electric 
If  Adopted, 
ually. 


73,000  Letters  Opened  in  8  Hours,  Is  the  Record  of 
This  New  Electric  Letter  Opener. 


are  opened  they  are  automatically  thrown 
out  and  stacked  up  in  the  case  of  the 
machine,  as  shown  in  the  illustration.  A 
1/20  h.p.  electric  motor  operates  it. 


ELECTRIC  DRIP  PAN. 

How  many  times  have  you  heard  mother 
say,  "Johnny,  empty  that  drip  pan,"  and 
when  you  undertook  to  carry  out  the  as- 
signed task  found  that  the  pan  was  filled 
to  overflowing,  and  possibly  had  flooded 
several  square  yards  of  carpet  about  the 
ice  box.  To  obviate  this  household  catas- 
trophe which  has  occurred  and  will  most 
probably  occur  many  thousand  times,  a  New 
York  inventor,  Mr.  M.  Jacobson,  has  re- 
cently obtained  a  patent  on  an  electric  drip 
pan  alarm  here  featured.  When  the  water 
reaches  a  certain  predetermined  level  in  the 
pan,  the  float  arm  rises,  causing  the  electric 


Magic  and   Black  Art  Still   Exercise  Their 
Charm  Upon  the  Public.     If  You  Don't  Be- 
lieve  It   Watch   the  Crowd   This  Magnetic 
Window  Novelty  Attracts. 


the  whole  device,  and  it  is  re- 
peatedly changed  in  position  by 
means  of  proper  gearing,  and 
an  electric  motor  hidden  in  the 
base. 

The  pedestal  supporting  the  ad- 
vertisement card  is  of  iron  so  that 
the  magnet  can  act  upon  it. 


NEW  TRAVELING  ELECTRIC 
TALKING  SIGN. 

Recent  improvements  in  the  talking  elec- 
tric sign  have  made  it  possible  to  either 
flash  the  message  in  consecutive  distinct 
flashes  or  continuously  traveling,  the  story 
moving  across  the  lamp  field  from  right 
to  left.  The  sign  can  be  supplied  in  any 
size,  either  for  outdoor  display  or  for 
store  or  show  window  use.  One  of  its 
greatest  features  is  that  it  can  flash  an 
advertisment  of  any  desired  length.  The 
system  consists  of  only  three  essential 
parts,  the  lamp  letter  field,  the  flash  con- 
troller for  the  operating  stencil,  and  the 
connecting  cable  which  joins  the  two. 

How  does  it  do  it?  The  words  are 
spelled  out  on  a  bank  of  very  closely 
spaced  electric  lamps.  The  lamp  bank 
may  be  of  a  size  to  flash  a  six-foot  or  six- 
inch  letter. 

The  word-flashes  are  operated  by  means 
of    a    motor-driven    stencil    ribbon,  per- 


AT 


To  Obviate  the  Overflowing  Drip  Pan  a  Re- 
cent Patent  Provides  for  a  Simple  Electric 
Alarm   Bell   and    Float  Switch,   Which  Act 
When  the  Pan  Is  Nearly  Full. 

bell  circuit  to  be  closed.  This  should  prove 
a  God-send  to  the  busy  housewife,  not  to 


OPENING    50  LETTERS 
ONCE    BY  MOTOR. 

Anyone  who  has  ever  had  to 
open  a  thousand  letters  by  hand  or 
by   hand-operated    letter  openers, 


the  enormity  of  the 
the  amount  of  time 
plete  the  operation, 
greatest     care  has 


The 
verti 
to  th 

knows 


task   involved  and 
necessary   to  corn- 
In    addition,  the 
to     be  exercised 


in  the  opening  process  in  order  that 
enclosures    be    not    mutilated.    This  can 


Latest  Electric  Talking  Sign  Enables  the  Ad- 
ser  to  Flash  a  Continuously  Changing  Message 
e  Public.  The  Letters  Move  From  Right  to  Left. 

forated  with  the  message.  This  ribbon  may 
be  practically  any  length.  It  may  be  con- 
tinuous so  as  to  repeat  the  message.  Sec- 
tions of  message-ribbon  may  be  added  at 
any  time  or  removed — all  in  a  few  min- 
utes. The  story  may  thus  be  kept  up  to 
the  minute. 


308 


THE  ELECTRICAL  EXPERIMENTER 


September,  1917 


Vocation  of  the  Engineer 

By  PROF.  A.  E.  WATSON 
Instructor  in  Electrical  Engineering,  Brown  University 


WHAT  is  an  engineer,  and  what 
does  he  do?  The  trade  definition 
is  obvious  and  simple,  but  the  pro- 
fessional application  is  meant,  and 
to  that  the  answer  is  not  so  easy; 
at  least  it  cannot  be  short.  New  extensions 
and  applications  of  the  name  are  constantly 
being  found,  suggesting  wide  differences  in 
the  definition. 

The  name  was  early  used  in  a  military 
sense,  for  to  the  "engineer  corps"  of  an 
army  was  assigned  the  detail  of  designing 
and  constructing  fortifications,  roads, 
bridges,  etc.  For  the  arts  of  peace  the 
building  of  canals  and  railroads  demanded 
similarly  skilled  men,  but  in  civil  life.  It 
was  in  the  decade  of  1865-1875  when  the 
first  great  transcontinental  railroads  were 
building  that  these  "civil"  engineers,  as  dis- 
tinguished from  the  military  engineers, 
were  recognized  as  forming  a  separate 
professional  body.  To  equip  railroads  and 
ships  with  their  motive  power,  great  fac- 
tories with  their  machinery  and  tools,  re- 
quired men  trained  along  quite  other  lines, 
and  the  mechanical  engineers  became  a  sec- 
ond professional  class.  Hand-in-hand 
with  these  latter,  at  first  perhaps  a  step 
behind,  but  now  with  the  slogan  "Do  it 
electrically,"  quite  in  line  with  his  elder 
brother,  the  electrical  engineer  has  found 
his  functions  both  a  demonstration  and  a 
challenge. 

Like  that  of  other  professions,  the  work 
of  engineers  is  constantly  becoming  more 
diverse  and  specialized.  With  the  multi- 
plication of  proofs  that  their  work  is  ordi- 
narily done  in  an  economical  and  reliable 
manner,  more  and  more  matters,  not  at 
first  regarded  as  properly  within  the  scope 
of  engineering,  have  been  entrusted  to  their 
advice,  judgment,  and  execution.  Thus  in 
addition  to  the  older  designation  of  "city 
engineer"  we  find  "public  service  engineer," 
"efficiency  engineer,"  "illuminating  engi- 
neer," "heating  engineer,"  etc.  It  is  from 
these  actual  instances  rather  than  from  a 
dictionary  that  the  present  usage  of  the 
word  is  to  be  derived. 

It  is  fortunate  that  all  of  us  are  not 
vitally  interested  in  the  same  things,  for 
a  certain  sort  of  life-work  that  is  a  source 
of  the  highest  inspiration  to  some  would 
be  of  most  depressing  drudgery  to  others. 
While  a  normal  man  is  sufficiently  re- 
sourceful and  energetic  to  adapt  himself 
to  circumstances,  and  to  derive  a  sufficient 
and  tolerable  subsistence  from  any  one  of 
a  variety  of  employments,  he  should  be 
given  free  choice  in  the  matter  of  selec- 
tion of  that  work  which  above  all  others 
appeals  to  his  whole  heart  and  mind.  Once 
entered,  upon  this  course  he  will  bode  no 
stint  or  limitation.  Some  have  heard  that 
call  in  engineering,  have  followed,  and  not 
been  deceived.  As  judged  by  their  own 
admissions  and  by  the  testimony  of  word 
and  deed,  they  have  done  the  work  for 
which  they  have  seemed  specially  fitted. 

What  shall  we  reply  then  to  the  young 
man  who  says,  "Engineering  is  just  what 
I  want.  How  can  I  get  into  it?"  If  pos- 
sible, even  from  the  first,  the  value  of  the 
personal  element  should  be  recognized.  Tell 
him  that  if  he  knows  of  an  engineer  with 
whom  he  can  get  acquainted,  let  him  do 
it.  Try  to.  visit  him  at  his  work,  or  even 
at  his  play.  If  engineers  or  engineering 
societies  in  the  neighborhood  have  meet- 
ings for  discussion,  let.  him  attend  such  as 
appear  to  furnish  subjects  of  interest. 
Ordinarily  the  public  is  cordially  invited 
to  such  gatherings.  Altho  many  of  the 
topics  may  be   over  the  young  visitor's 


Prof.  A.  E.  Watson,  Instructor  in  Electrical 
Engineering,  Brown  University,  Is  to  Our 
Mind  An  Ideal  Educator  and  Scholar.  He 
Holds  Degrees  of  B.  Sc.,  and  Ph.  D.,  and  Is 
a  Member  of  the  A.  I.  E.  E.  Besides  His 
Tutorial  Duties  He  Finds  Time  to  Write 
Technical  Books  and  Papers,  and  We  Are 
Pleased  to  Present  His  Message  to  Embryo 
Engineers  Herewith. 

head,  he  will  be  sure  to  become  interested 
in  certain  of  the  attendants,  and  some  of 
the  members  will  become  interested  in  him. 


|  IN  THE  OCTOBER  "E.E."  § 

H  "Research  in  High  Frequency,  High  ZZ 

H  Potential  Currents,"  by  Dr.  Nikola  = 

g  Tesla.  g 

H  An  automatic  electric  " zig-zaggcr,"  g 

g  to  prevent  torpedoing  of  ships.  || 

H  The   marvels    of   Radio-activity —  g 

H  Part  III — by  Jerome  S.  Marcus,  B. Sc.  ZZ' 

H  Electricity  in  the  manufacture  of  g 

—  Ammunition  and  Guns.  = 
g  "A  new  electrical  war  scheme" —  g 

—  by  H.  Gernsback.  g 
§§  The  American  inventor  of  Radio  = 
H  who  antedated  Marconi.  |§ 
=  The  earliest  electrical  apparatus —  g 

—  an  article  of  historic  and  technical  || 
g  interest,  by  H.  Winfield  Secor.  = 

Chemical  action  of  storage  batteries  = 

H  — of  interest  to  all  electrical  and  radio  g 

H  students,  by  Albert  W.  Wilsdon.  H 

H  New  and  startling  experiments  with  — 

g  High  Frequency  Currents — Lighting  g 

ZZ  a  bank  of  110  volt  lamps  thru  the  g 

g  body,  and  a  host  of  other  extremely  g 

H  interesting  and  mystical  experiments.  ZZ 

H  Radio-dynamics — the    control    of  g 

g  torpedoes,  boats,  et  cetera,  by  wireless  g 

=  waves.    Some  recent  developments  in  g 

=  this  field.  — 

g  The  How  and  Why  of  Radio  Ap-  g 

H  paratus — Part  5.    Helices  and  Oscil-  g 

H  lation  Transformers.  — 

H  The  ''October  issue"  will  be  of  par-  g 

§§  ticular  interest  to  all  classes  of  read-  g 

g  ers.    It  will  mark  the  official  opening  '= 

g  of  the  "working"  season.    We  will  all  g 

ZZ  be   back  from  vacations   then   and  ZZ 

=  ready  to  study  up  on  the  latest  ad-  ZZ: 

=  vances  in  electricity,  radio  and  science  §§ 

g  — which   "The  Electrical  Expert-  = 

ZZZ  menter"  knows  just  how  to  serve.  ZZ 

g  Don't  miss  it,  Friends!  v 

IllllHlllllllllllllllllllllllllllllllllllllllllllllllllH 


This  association  should  quicken  his  intel- 
lect and  unfold  to  him  some  of  the  prob- 
lems of  the  engineers  and  their  tentative 
or  final  solutions.  Let  him  subscribe  for 
an  engineering  magazine,  and  read  such 
others  as  may  be  available.  Without  inter- 
fering with  regular  school  or  other  work, 
such  an  enquiry  extending  over  a  couple  of 
years  will  demonstrate  if  the  interest  in 
engineering  matters  is  merely  transient  or 
is  likely  to  be  permanent.  Once  in  the  life- 
work  the  competition  between  one's  fellows 
is  altogether  too  real  to  permit  trifling 
with  the  original  selection. 

To  have  any  reasonable  chance  of  get- 
ting into  the  first  rank  of  engineers  or 
even  of  good  standing  in  the  profession, 
the  aspirant  should  have  a  college  or  tech- 
nical school  degree.  Of  course  numerous 
instances  can  be  quoted  of  successful  engi- 
neers who  have  not  received  such  formal 
education,  but  they  will  be  found  to  con- 
sist mostly  of  the  older  generation  whose 
schooling  came  before  the  present  numer- 
ous and  comparatively  easy  opportunities 
for  education  were  afforded.  Immediately 
after  graduation,  two-year  training  courses 
are  ordinarily  available  in  some  consulting, 
designing,  erecting,  operating  or  manu- 
facturing concern.  During  such  a  coarse  the 
"student-engineer"  receives  a  living  wage, 
say  $60.00  to  $75.00  per  month,  and  is  fre- 
quently transferred  from  one  department 
to  another,  whereby  he  acquires  a  working 
familiarity  with  a  great  variety  of  sub- 
jects or  apparatus.  During  such  a  course 
or  at  its  completion,  the  embryo-engineer 
is  supposed  to  have  made  a  sufficient  im- 
pression upon  his  employers  as  to  merit 
an  appointment  to  their  permanent  staff, 
or  to  secure  a  recommendation  to  some 
allied  interest,  or  to  warrant  his  getting 
into  business  more  of  his  own  making. 
He  can  now  properly  call  himself  an  engi- 
neer, but  to  secure  that  recognition  from 
his  fellows  he  should  make  application  for 
membership  in  one  of  the  national  engi- 
neering societies.  Its  publications  and  asso- 
ciations should  prove  of  lifelong  interest. 

Thus  scheduled  it  would  appear  that  the 
engineer  has  to  a  considerable  degree  been 
the  product  of  artificial  methods,  that  he 
has  been  machine-made,  without  the  rec- 
ognition of  the  inventive  and  creative  at- 
tributes usually  ascribed  to  one  of  his  pro- 
fession. Perhaps  this  criticism  may  occa- 
sionally be  heightened  by  hearing  a  sea- 
soned veteran  maintain  that  engineering 
consists  simply  of  good  common  sense.  In 
reality,  however,  such  a  statement  hardly 
puts  the  case  strongly  enough,  for  success- 
ful engineering  will  be  found  to  consist 
of  uncommonly  good  sense.  In  this  last 
expression  is  to  be  summed  the  whole 
school  education  of  the  man,  then  tem- 
pered and  supplemented  with  years  of  ex- 
perience. The  weight  of  increasing  re- 
sponsibilities in  connection  with  important 
and  even  stupendous  enterprises  may  dim 
the  recollection  of  college  and  apprentice 
days,  but  that  early  training  is  indispen- 
sable. 

The  expectant  engineer  may  well  con- 
sider that  his  life-work  will  bring  him  in 
touch  with  city  councils,  with  legislative 
committees  and  assemblies,  with  courts  of 
law,  with  financial  interests,  and  undertak- 
ings. He  may  be  called  upon  to  give  pub- 
lic addresses  and  to  prepare  papers  for 
publication.  His  word  and  action  will  be 
critically  watched,  for  the  engineer  must 
make  no  mistakes.  Life  and  property  are 
too  valuable  to  serve  as  subjects  for  snap- 
judgments  and  ill-considered  experiments. 


September,  1917  THE  ELECTRICAL  EXPERIMENTER  309 


X-Ray  Tubes  for  High  Frequency  Coils 

By  Dr.  FREDERICK  FINCH  STRONG 
Lecturer  on  Electro-therapeutics,  Tufts  Medical  School,  Boston 


IN  all  the  history  of  scientific  achieve- 
ment there  has  been  perhaps  no  dis- 
covery of  such  a  startling  and  revolu- 
tionary character  as  that  of  the  X-Ray. 
The  Electron  theory,  which  forms  the 
basis  of  the  chemistry  and  physics  of  our 
New  Age  has  been  formulated  almost  en- 


dealing 


Standard  Form  of  Single-Focus  High  Frequency  X-Ray 
Tube.    The  First  Powerful  X-Ray  Tubes  Were  Excited 
By  a  High   Frequency  Oscillator. 


tirely  from  deduction  made  possible  by  the 
work  of  Roentgen  and  the  Curies. 

If  we  review  the  history  of  these  dis- 
coveries we  find  that  they  have  resulted 
from   long   series   of  researches 
with  the  phenomena  of  electrical 
discharges  in  partial  vacua. 

The  air  pump  was  invented  in 
1650  by  Otto  von  Guericke;  by 
its  use  Sir  W.  Snow  Harris,  in 
1834  was  able  to  show  that  the 
spark-length  of  a  given  electrical 
machine  increases  in  inverse 
ratio  to  the  pressure  of  the  gas 
thru  which  it  passes.  His  tubes 
were  exhausted  to  about  one 
five-hundredth  of  an  atmosphere, 
and  the  dischage  took  the  form 
of  a  pencil  of  violet-pink  light. 

Geissler,  in  1838,  experimented 
with  discharges  in  low  vacua, 
and  invented  the  beautiful  tubes 
which  bear  his  name.  By  im- 
proving the  air-pump,  he  was 
able  to  withdraw  all  but  one  ten- 
thousandth  of  the  original  air 
from  the  glass  tube,  and  change  the  color 
of  the  glow,  in  the  electrified  space  from 
violet-pink  to  a  pure  white. 

The  invention  of  the  mercury  air-pump 
by  Sprengel  in  1865,  made  it  possible  for 


an  atmosphere.  He  gave  to  the  world  the 
"Crookes  tube,"  with  which  Lenard  in 
1894,  proved  the  existence  of  the  "Cathode 
rays,"  and  from  which  in  1895,  Roentgen 
accidentally  discovered  a  new  form  of 
emitted  energy  which  he  tentatively  called 
the  "X-Ray." 

We  all  recall  the  circumstances 
of  this  discovery.  Roentgen 
was  experimenting  with  a 
Crookes  tube  enveloped  in  an 
opaque  cover,  when  he  noticed 
a  bright  glow  on  a  nearby  card, 
coated  with  Platinum-Barium- 
Cyanid.  The  glow  continued 
even  when  the  uncoated  sur- 
face of  the  card  was  presented 
to  the  tube,  and  further  ex- 
periment showed  that  the  inter- 
position of  the  experimenter's 
hand  between  the  covered  tube 
and  the  fluorescent  screen 
would  cause  a  shadow-picture 
of  the  bones  to  appear  upon 
the  glowing  surface. 
The  publication  of  Roent- 
gen's discovery  led  investigators  in  all  parts 
of  the  world  to  study  the  new  phenomena. 
Static  machines  and  Ruhmkorff  induction 
coils  were  at  first  employed  to  excite  the 
Crookes  tubes ;  but  the  intensity  of  the  re- 


may  be  made  in  the  fraction  of  a  second. 

For  the  general  practitioner,  the  dentist 
and  the  amateur  experimenter,  however,  the 
high-frequency  apparatus  is  still  the  most 
convenient  and  inexpensive  device  for  ex- 


Po/ /ad turn  ft  'be 


The  Simple  X-Ray  Tube  Contains  an  Anode 
or  Target  "a"  and  an  Aluminum  Cathode 
"b."  The  Cathodic  Electron  Bombardment 
of  Target  "a"  Causes  X-Rays  to  be  Produced 
At  Right  Angles  or  Downward  As  Shown. 

Sir  William  Crookes  in  1878,  to  study  elec- 
trical discharges  in  rarefied  gases  with 
pressures  as  low  as  one  one-millionth  of 


Commercial  Form  of  a  Second  Type  of  Single-Focus  H 
quency  X-Ray  Tube  Shown  Sectionally  in  Fig.  4.    These  T 
Adapted  to  High  Power  Tesla  or  Oudin  Coils 

suiting  X-rays  was  not  very  great.  In  those 
days  an  induction  coil  giving  a  four-inch 
spark  was  regarded  as  exceedingly  power- 
ful. We  know  now  that  such  an  apparatus 
is  entirely  inadequate  to  the  production  of 
X-rays  for  any  practical  purpose. 

Tesla  and  Elihu  Thompson  advocated 
high-frequency  currents  for  X-ray  gener- 
ation, and  in  1896  the  Knott  Apparatus 
Company  of  Boston  designed  the  first  prac- 
tical commercial  X-ray  machine.  It  con- 
sisted of  an  open-core  transformer,  glass- 
plate  condenser  and  Tesla  coil,  immersed 
in  oil,  and  a  rotary  spark-gap  not  unlike 
those  now  used  in  Radio-telegraphy. 

A  few  months  later,  the  writer  made  the 
first  practical  high-frequency  apparatus 
haying  solid  insulation  instead  of  oil,  and 
suitable  for  therapeutic  as  well  as  X-ray 
work.  The  many  types  of  high-frequency 
machines  that  are  now  made  for  physi- 
cians' use  are  but  variations  and  improve- 
ments of  this  original  apparatus. 

At  the  present  time  the  professional 
Roentgenologist  uses  almost  exclusively 
powerful  apparatus  of  the  high-tension 
transformer  type ;  the  high-voltage,  low- 
frequency,  alternating  current  being  recti- 
fied by  a  high-tension  commutator  oper- 
ated by  a  synchronous  motor.  With  such 
an  apparatus  and  suitable  X-ray  tubes,  a 
skiagram  of  the  adult  thorax  or  abdomen 


Special  Form  of  X-Ray  Tube  of  the  Single- 
Focus  Type,  Fitted  With  Palladium  Vacuum 
Regulator  and  Focussing  Mirror  "C1",  Also 
Copper  Cone  "d,"  for  Dissipating  Auxiliary 
Cathode  Stream. 

citing  X-ray  tubes,  and  produces  results 
quite  adequate  to  their  respective  needs. 

The  construction  of  an  X-ray  tube  is 
familiar  to  all : — in  its  simplest  form  it 
consists  of  a  Crookes  tube  (as  shown  in 
Fig.  1),  containing  an  anode  or 
target  (a),  faced  with  platinum 
or  tungsten,  and  a  concave 
aluminum  cathode  (b).  A  high- 
voltage,  unidirectional  current 
flowing  thru  the  tube  causes 
streams  of  electrons  to  pass 
from  the  cathode  to  the  target, 
which  is  set  at  an  angle  of  forty- 
five  degrees  to  the  axis  of  the 
tube.  The  electronic  stream 
("Cathode  rays"),  is  reflected  at 
right  angles  and  part  of  the  en- 
ergy is  transformed  into  X-rays, 
which  emerge  from  the  glass  in 
a  divergent  cone,  as  shown. 
Such  a  tube  is  not  suited  for  use 
with  alternating  or  oscillating 
currents,  as  a  double  set  of  rays 
would  be  produced;  this  would 
tend  to  melt  the  aluminum 
cathode  and  cause  the  absorption  of  the 
residual  gas  in  the  tube  so  that  it  would 
soon  be  too  "hard"  to  use. 

This  led  Elihu  Thompson,  in  1896,  to 
invent  his  "double-focus  tube";  the  con- 


igh  Fre- 
ubes  Are 


The  Original  Thompson  Double-Focus  High 
Frequency  X-Ray  Tube  Which  Really  Com- 
prised Two  Distinct  Bulb  Elements. 

struction  and  operation  of  the  Thompson 
double-focus  tube  is  shown  in  Fig.  2. 
(Continued  on  page  328) 


310 


THE  ELECTRICAL  EXPERIMENTER 


September,  1917 


The  Franklin  Experimental  Club 


By  WILLIAM  J.  HAMMER 

Consulting  Electrical  Engineer 


UE  to  the  exigencies 
of  the  World's  War, 
our  Government  has 
deemed  it  advisable 
to  dismantle  the 
many  Wireless 
Plants  about  the 
country  which  might 
be  used  to  convey 
messages  to  the 
enemy,  and  strict 
regulations  are  at 
present  in  force. 
Doubtless  there  are  thousands  of  enterpris- 
ing and  ambitious  boys  all  over  the  country 


wire,  chemicals,  etc.,  as  well  as  a  library 
of  technical  books  and  papers,  and  where 
each  boy  will  be  enabled  to  avail  himself 
at  small  expense  of  the  club's  facilities  and 
secure  the  benefit  of  the  criticism  and  help 
of  the  other  members  and  perhaps  the  valu- 
able advice  and  co-operation  of  older  men 
in  the  community  who  have  had  experi- 
ence in  scientific  matters.  Such  men,  for 
instance,  as  the  teachers  of  science  in  the 
local  public  schools,  whom  he  feels  con- 
fident would  be  glad  to  assist  the  boys  in 
organizing  and  conducting  the  club,  for 
they  realize  the  great  benefits  which  come 
from  doing  things  with  one's  hands  and 


The  Electrical  Side  of  the  "Franklin  Experimental  Club's"  Laboratory  and  Work-Shop.  Every 
Member  Had  His  Own  Tool  Drawer  and  Prizes  Were  Given  Monthly  for  the  Best  Original 

Piece  of  Work  Or  Experiment. 


who  have  constructed  and  operated  wire- 
less plants  at  their  homes  whose  ardor  for 
scientific  knowledge  and  experimentation 
has  been  somewhat  cooled  by  their  inability 
to  operate  their  stations. 

The  writer  has  noted  with  great  inter- 
est the  illustrations  of  wireless  installa- 
tions, many  of  them  elaborately  equipt  for 
both  sending  and  receiving  wireless  mes- 
sages ;  which  have  been  designed  and  built 
by  amateurs  all  over  the  country  who  have 
sent  in  photographs  and  data  regarding 
their  installations  for  reproduction  in  the 
columns  of  The  Electrical  Experimenter, 
and  he  has  a  fellow  feeling  for  these  young 
men,  as  he  has  dabbled  somewhat  in  this 
field  himself  and  believes  that  he  was  the 
first  person  in  the  world  to  use  wireless 
for  domestic  purposes  in  1894.  (See  Elec. 
Review,  Feb.  25,  1905).  Therefore,  he 
would  like  to  make  a  suggestion  to  the 
host  of  "Electrical"  and  "Radio  Bugs" 
about  the  country  which  might  further 
stimulate  their  interest  in  scientific  mat- 
ters, for  which  their  work  in  wireless  has 
already  given  them  a  keen  taste. 

The  writer's  suggestion  is  that  in  various 
communities  boys  interested  in  wireless  and 
other  branches  of  electrical  science,  phy- 
sics, chemistry,  etc.,  get  together  and  form 
a  scientific  club  where  they  can  study,  ex- 
periment, build  apparatus  and  models, 
where  they  can  gradually  collect  tools, 
instruments  and  supplies  such  as  batteries, 


believe  that  boys  should  be  encouraged  to 
do  useful  work  of  this  character  and  they 


also  realize  that  there  are  few  things  out 
of  which  boys  can  derive  as  much  pleas- 
ure. 

Perhaps  the  "Electrical"  and  "Radio 
Bugs"  to  whom  this  article  is  addrest  and 
who  may  consider  forming  such  a  scien- 
tific club  may  secure  some  useful  sugges- 
tions if  the  writer  tells  them  of  such  a 
club  which  he  took  the  initiative  in  form- 
ing and  in  which  he  was  greatly  interested 
for  several  years  until  a  serious  fire,  which 
started  in  an  adjoining  alleyway,  destroyed 
the  club's  headquarters,  causing  him  a  per- 
sonal loss  of  several  thousand  dollars  in 
apparatus,  books,  tools,  etc.,  which  he  had 
loaned  the  organization,  and  unfortunately 
putting  a  quietus  upon  the  club's  activities. 

The  Franklin  Experimental  Club  of 
Newark,  N.  J.,  was  organized  January  31st, 
1890.  The  object  of  the  club  as  stated 
in  its  constitution  was  "the  advancement  of 
its  members  in  scientific  knowledge  by 
study  and  experimental  research  thru  the 
helpful  influence  of  united  effort." 

This  modest  little  club  was  really  the 
result  of  the  writer's  previous  unsuccess- 
ful efforts  made  years  before  to  interest 
certain  prominent  men  in  the  formation  of 
an  Institution  in  New  York  City  where 
Popular  Scientific  Lectures  would  be  given, 
where  there  would  be  a  scientific  museum 
of  models  of  historical  value,  and  also  con- 
taining many  working  models  and  instru- 
ments, each  demonstrating  some  scientific 
principle,  and  each  accompanied  by  an  ap- 
propriate explanatory  card.  Keys,  push- 
buttons and  switches  for  operating  the  ap- 
paratus would  be  supplied  and  instead  of 
the  usual  notice  everywhere,  "Please  do 
not  handle,"  the  visitor  would  be  requested 
to  "handle  everything"  and  more  than 
this,  the  proposed  lyceum  was  to  have  ex- 
perimental laboratories  and  workshops 
where  young  men  without  means  who 
showed  an  aptitude  for  scientific  investiga- 
tion and  were  properly  fitted  and  desirous 
of  availing  themselves  of  such  opportuni- 
ties, would  be  supplied  without  cost  to  them 
with  instruments,  tools  and  appurtenances 
for  such  work,  and  could  prosecute  their 
studies  and  experiments  under  qualified  in- 
structors.    However,  such  a  plan  did  not 


Another  View  of  the  Well-equipt  Laboratory,  Showing  Part  of  the  Chemical  Apparatus  At 
Extreme  Left.    Such  a  Club  Is  a  Real  A«set  to  Any  City  Or  Town.    There  Ought  to  Be  50,000 

of  Them  Right  Now. 


September,  1917 


THE  ELECTRICAL  EXPERIMENTER 


311 


receive  the  necessary  encouragement. 
Some  years  later  (1889)  while  visiting  Ber- 
lin, Germany,  with  Mr.  and  Mrs.  Edison, 
we  were  shown  thru  the  New  "Urania" 


lection  of  flags  of  all  nations  which  the 
writer  had  collected  in  his  various  trips  to 
Europe.  A  case  containing  a  collection  of 
butterflies,  bugs  and  insects,  which  he  had 


monthlies,  several  quarterlies,  and  a  num- 
ber of  weeklies  were  on  file,  and  it  is  well 
to  note  that  publishing  and  supply  houses 
not  only  gave  the  club  special  rates,  but 


The  Wonderful  Electrical  Dinner  Given  by  the  "Franklin  Experimental  Club"  And  Which  Was  Attended  By  Many  Notable  Guests.  Franklin 
(Thanks  to  a  Concealed  Phonograph)  Repeated  His  Proverbs.  The  Electric  Railway  Hustled  Cigars  Around  the  Table,  the  Skulls  Flashed 
and  Howled,  Oysters  Sizzled  In  An   Electric  Cooker,  While   Bennie  Franklin  Drew  Lightning  Now  and  Then  From  the  Kite  String.  It 

Was  "Some"  Dinner,  Fellow  "Muckers,"  Take  It  From  Your  Uncle  William. 


Museum  by  the  chief  director  and  origi- 
nator, Dr.  Werner  Siemens,  and  the  writer 
saw  that  here  was  a  small  model  of  the 
very  institution  which  he  had  tried  pre- 
viously to  establish  in  New  York  and  he 
decided  upon  his  return  to  America  to 
start  a  scientific  club  in  a  small  way  hop- 
ing that  its  earnest  work  and  actual  ac- 
complishments would  cause  public  spirited 
men  to  extend  it  into  the  original  plan  he 
had  conceived. 

The  accompanying  illustra- 
tions, Fig.  1,  2,  and  3,  give  a 
fair  idea  of  the  exterior  and  in- 
terior of  the  club  headquarters, 
which  the  members  facetiously 
dubbed  the  "Chinese  Laboratory" 
by  reason  of  its  occupancy  of 
the  premises  over  Mr.  Sing 
Lee's  laundry.  The  club  and 
Mr.  Sing  Lee  were  soon  on 
speaking  terms,  due  _  among 
other  things  to  the  "high  peri- 
odicity" of  the  upset  battery  jars 
and  chemicals  in  the  club 
rooms. 

The   bare   beams    and  walls 
were  covered  with  heavy  paper 
and    hung    with    many    photo-  obverse 
graphs,  pictures,  diagrams,  etc.,   which  Ea 
and  later  draped  with  a  fine  col- 


caught  and  mounted  while  an  assistant  at 
Mr.  Edison's  laboratory  at  Menlo  Park, 
N.  J.,  1880-1,  may  be  noted  in  one  of  the 
accompanying  photos. 

One  side  of  the  Club  room  was  devoted 
to  electrical  and  physical  apparatus  and  the 
other  side  to  chemical  apparatus,  while 
work  tables  and  benches  ran  around  the 
walls  and  down  the  center  of  the  room. 

The  club  possest  quite  a  fine  library  of 
technical  books  and  some  twelve  scientific 


frequently  sent  us  things  with  their  com- 
pliments, and  certain  publications  put  the 
club  on  their  free  list.  The  various  mem- 
bers also  loaned  books,  instruments,  tools, 
etc.  Professor  George  C.  Sonn  of  the  New- 
ark Public  High  School  and  the  Club's 
Curator  and  Historian,  was  one  of  the  club's 
most  valued  supporters. 

Each  member  received  a  handsome  cer- 
tificate of  membership  bearing  Franklin's 


portrait. 


nd  Reverse  of  Souvenir  Medallion  of  Benjamin  Franklin 
ch  Guest  At  the  "Franklin  Experimental  Club"  Electrical 
Dinner  Received.     A  Pleasing  Memento. 


The  initiation  fee  was  $5,  and 
the  dues  $1  per  month.  The 
dues  were  expended  for  rent  and 
the  purchase  of  apparatus  and 
supplies.  Each  member  was 
supplied  with  keys  to  the  club 
and  access  could  be  had  at  all 
times,  night  and  day,  and  each 
had  a  special  drawer  for  his 
tools,  apparatus,  etc.,  and  a  sec- 
tion of  the  work  bench.  All  ap- 
paratus, tools,  books,  etc., 
whether  the  property  of  the 
club  or  of  individual  members, 
were  at  the  disposal  of  all  mem- 
bers and  were  under  the  guard- 
ianship of  the  Club  Curator. 

Lectures  and  informal  talks 
and  demonstrations  were  fre- 
quently given. 


312 


THE  ELECTRICAL  EXPERIMENTER 


September,  1917 


Experimental  Physics 

By  JOHN  J.  FURIA,  A.  B.,  M.  A. 
Instructor  in  Physics  and  Science  Master,  Riverdale  Country  School 


TALKING 


LESSON  7. 
Sound. 

WE  all  pity  the  unfortunate  per- 
son who  is  born  deaf  and  has  to 
go  thru  life  without  hearing  a 
sound.  He  never  has  the  oppor- 
tunity of  hearing  the  exquisite 
music  of  people  eating  soup,  of  the  baby 
next  door  yowling  twenty-four  hours  a 
day,  of  the  rollick- 
ing ragtime  rattle  of 
the  square  piano 
downstairs,  of  the 
straining  of  the  vo- 
cal cords  of  Miss 
Nightingale  upstairs 
while  she  sings  the 
"ahs"  and  "ohs"  and 
"ees"  preliminary  to 
allowing  the  impresarios  fight  each 
other  as  to  who  shall  have  her  ser- 
vices at  $5,000  per,  for  the  next 
season's  opera.  Never  does  our 
poor  unfortunate  hear  the  strains 
of  Heine's  little  German  Band 
playing  in  the  back-yard,  nor  does 
he  hear  the  harmony  of  the  cat 
quintet. 

The  question  arises,  "if  we  were 
all  deaf,  would  .there  be  no  sound?" 
Believing  that  the  world  could  not 
possibly  get  along  without  the 
above  enumerated  soothing  sounds, 
we  are  gratified  that  in  so  far  as 
"Physics"  is  concerned,  the  sound 
really  does  exist,  whether  anyone 
hears  it  or  not.  When  -we  hear  the 
sound  it  simply  means  that  the 
Physical  sound  is  causing  a  Physi- 
ological sensation  in  us.  In  every- 
day life  sounds  are  usually  dis- 
turbances. Therefore  the  grouch 
will  be  gratified  to  learn  that  Phy- 
sics teaches  us  that  all  sounds  are  always 
disturbances  (of  the  air). 

EXPERIMENT  40— Place  about  half  a 
cup-ful  of  water  in  a  large  Florence  flask 


tinctly.  This  leads  us  to  the  first  impor- 
tant consideration  that  sound  will  not  travel 
in  a  vacuum.  The  clapper  hit  the  sides 
of  the  bell  in  both  cases ;  and  if  now  the 
stopper  is  removed  and  the  air  allowed 
to  pass  into  the  flask,  on  shaking,  the  bell 
will  again  ring. 

The  question  naturally  arises,  "What 
caused   the   vacuum  ?"     When  the  water 


T/GH.TL  Y  STRETCHED  STRING 


ry-33- 


LISTENING 


BOTTLES  Of 
WATER. 


To   Demonstrate  That  Sound   Is  Conducted 
Thru  the  Air  and  Not  Thru  the  Ether,  Try 
to  Make  a  Bell  Ring  in  a  Vacuum. 


(or  thin  bottle  which  can  be  heated  with- 
out breaking).  Stick  a  heavy  wire  thru 
a  rubber  stopper  which  fits  the  flask  tightly, 
and  attach  a  small  bell  (such  as  hangs  on 
pussy's  neck  to  warn  the  mice  that  she 
is  approaching)  to  the  end  of  the  wire  as 
in  Fig.  30.  If  now  with  the  stopper  tightly 
in  place  the  flask  is  shaken,  the  bell  is 
heard  distinctly.  Remove  the  stopper  with 
bell  attached  and  place  the  flask  on  a 
Bunsen  flame  or  stove  and  allow  the  water 
to  boil  several  minutes.  Then  replace  the 
stopper  tightly ;  allow  the  flask  to  cool  and 
when  sufficiently  cool  run  cold  water  over 
it.  If  now  the  flask  is  shaken  the  bell 
will  not  be  heard  and  if  the  stopper  is 
not  airtight  it  will  be  heard  only  indis- 


Fig.  33  Illustrates  the  Well-Known  Tin-can  Telephone,  Which 
Shows  the  Principle  of  Sound  Conduction  by  Means  of  a 
Vibrating  String.  Fig.  34  Shows  the  Principle  of  the  Organ 
Pipe.  The  Air  Columns  Are  Set  in  Vibration  by  Blowing 
Over  Them. 


was  heated  the  steam  from  the  water  dis- 
placed the  air  in  the  flask  and  caused  the 
air  to  leave.  As  the  flask  was  cooled  the 
steam  condensed  to  water  again  and  if 
the  stopper  was  airtight  since  no  air  could 
enter  to  replace  the  steam,  a  vacuum  was 
left  above  the  water  in  the  flask.  The 
fact  that  sound  will  not  travel  thru  a 
vacuum  and  that  when  a  sound  is  made 
the  surrounding  air  moves  violently,  as  for 
example  when  the  automobilist  has  a  blow- 
out, or  when  an  explosion  occurs,  etc., 
leads  us  to  the  next  important  consider- 
ation, namely,  that  sound  is  a  disturbance 
of  some  medium — usually  the  air. 

As  far  as  Physics  is  concerned  the  sound 
occurs  if  the  air  is  disturbed,  whether  there 
is  anyone  present  to  hear  the  sound  or 
not.  On  careful  consideration  one  will 
grant  that  this  is  the  logical  way  to  look 


at  it,  just  as  one  grants  that  the  Sun 
shines  at  night  even  tho  we  do  not  happen 
to  see  it.  Light  exists  while  we  are  in  a 
dark  cellar,  but  we  do  not  happen  to  be 
getting  the  physiological  sensation.  In 
other  words,  the  question  of  whether  or 
not  a  sound  exists  if  no  one  is  around  to 
hear  it  is  identical  with  the  question  of 
whether  light  exists  if  we  shall  all  become 
blind  suddenly.  The 
actual  physical  phe- 
nomena exist  in 
both  cases,  and  it  is 
the  Physical  phe- 
nomena of  sound 
that  the  Physicist 
deals  with.  The 
Physiologist  and 
Psychologist  deal 
with  the  sensations  which  the  hu- 
man being  interprets  as  light  or 
sound. 

EXPERIMENT  41  —  Everyone 
has  noticed  that  the  lightning  flash 
is  seen  before  the  thunderclap  is 
heard.  Anyone  who  has  been 
present  when  a  cannon  is  fired  at 
a  distance  from  him  has  noticed 
that  the  sound  of  the  cannon  is 
not  heard  until  after  the  flash  is 
seen.  On  the  other  hand  if  one 
is  close  to  the  cannon  the  flash 
and  sound  appear  to  occur  at  the 
same  time.  It  is  evident  that  sound 
travels  more  slowly  than  light  (for 
all  practical  purposes  light  can  be 
taken  to  travel  instantaneously)  and 
it  is  interesting  to  measure  just 
how  fast  sound  does  travel.  Two 
persons  are  necessary  to  perform 
this  experiment,  but  it  is  by  no 
means  complicated  and  does  not 
require  any  elaborate  apparatus 
except  a  stop-watch,  which  may  be 
borrowed  for  the  occasion.  A  piece  of 
metal  is  attached  to  the  end  of  a  broom 
handle  or  other  stick  and  a  handkerchief 


Ficf.32 

< 

■Sfl 

1  1  1 

.Gong  or  be// 

Broom  \ 

\ 

fig.  3/ 

A    Simple    Experiment    in    Measuring  the 
Velocity  of  Sound  by  Means  of  a  Flag,  a 
Gong,  and  a  Stop-watch. 


Another  Scheme  for  Checking  Up  the  Veloc- 
ity  of   Sound    by    Means   of   the  "Seconds 
Pendulum."   Sound  Travels  at  1,100  Feet  Per 
Second. 

is  tied  as  in  Fig.  31.  A  gong  or  old  bell 
or  a  large  cow  bell  such  as  is  used  on 
New  Year's  Eve,  is  suspended  so  as  to 
hang  freely.  Thirty-three  hundred  feet  is 
measured  out  from  the  gong  by  use  of  a 
tape,  or  string  of  known  length,  or  by 
taking  1,100  paces  if  your  pace  is  three 
feet.  Your  partner  stands  there  with  a 
stop-watch  and  watches  the  gong.  Stand- 
ing below  the  gong  you  wave  the  im- 
provised flag  from  the  horizontal  position 
slowly  to  and  past  the  gong.  At  the  given 
signal  you  wave  slowly  past  the  gong 
three  times  at  an  even  rate  of  speed ;  at 
(Continued  on  page  345) 


September,  1917 


THE  ELECTRICAL  EXPERIMENTER 


313 


Manufacturing  Magnetism 

By  ROGERS  D.  RUSK,  B.  Sc. 


MAGNETISM  is  such  a  common 
force  today  that  we  hardly  ever 
stop  to  think  how  it  is  made  or 
why  we  do  not  make  more  of  it, 
why  we  do  not  use  it  to  sweep 
the  submarines  from  the  sea,  or  why  we 


nuc/ec/s  \ 

 — 

C  i 

fig  J           .  j 

  / 

Electron 

The  Old  Theory  of  Magnetism  Has  Under- 
gone a  Revolutionary  Change  in  the  Science 
of  To-day.  Each  Atom  Is  Now  Believed  to 
Comprise  a  Positive  Nucleus  or  Center, 
About  Which  the  Negative  Particles  (Elec- 
trons) Rotate  At  High  Velocity. 


do  not  use  it  to  put  out  of  commission  the 
delicate  machinery  of  some  distant  enemy. 
In  the  first  place  it  has  never  been  possible 
to  direct  a  magnetic  field 
or  concentrate  it  at  a  distant 
point.  Then  iron,  our  most 
magnetic  element,  can  only  be 
magnetized  to  a  certain  intens- 
ity known  as  the  saturation 
value.  Further  than  that  man 
has  been  producing  magnetism 
in  the  same  old  way  ever  since 
its  discovery  by  stroking  a  piece 
of  steel  with  the  pole  of  an- 
other magnet  or  by  placing  an 
iron  core  in  a  coil  of  wire  thru 
which  a  current  is  flowing. 
This  latter  is  the  same  process 
by  which  the  magnetism  of  the 
motor,  the  dynamo,  the  trans- 
former, or  the  electro-magnet, 
is  produced.  A  current  flows  in 
a  solenoid  about  a  core  of  iron 
when  lo  and  behold,  the  iron 
becomes  a  magnet.  Until  lately 
there  has  never  been  another 
method  by  which  magnetism 
could  be  produced  except  by 
placing  the  body  to  be  magne- 
tized in  such  a  magnetic  field,  either  that  due 


been  found  out  about  magnetism.  Several 
magnetic  alloys  have  been  found  which  are 
composed  of  metals  not  magnetic  in  them- 
selves. Iron,  which  was  long  supposed  to 
be  the  most  permeable  substance  known, 
has  now  been  surpast  by  one  of  its 
alloys,  and  Dr.  S.  J.  Barnett,  of  Ohio  State 
University,  has  discovered  a  totally  new 
method  of  producing  magnetization  not  de- 
pendent on  the  ordinary  electro-magnetic 
processes,  but  one  the  theory  of  which 
reaches  back  to  the  fundamental  constitu- 
tion of  matter  itself,  and  is  based  upon 
simple  laws  of  mechanics. 

Mother  Nature  herself  has  always  been 
the  greatest  manufacturer  of  magnetism, 
for  in  some  strange  and  mysterious  way 
she  keeps  a  supply  permeating  the  earth 
all  of  the  time.  If  the  earth's  magnetism, 
weak  as  it  is,  could  be  concentrated  at  a 
single  point  it  would  be  over  a  trillion  times 
stronger  than  the  strongest  field  ever  pro- 
duced, and  it  would  pull  the  largest  dread- 
naught  afloat  right  out  of  the  water  and 
over  the  land ! 

If  we  could  manufacture  magnetism  in 
the  same  way  that  the  earth's  magnetism 
is  being  continually  generated,  or  if  we 
could  find  some  element  or  compound 
vastly  more  magnetic  than  iron,  industry 
would  be  revolutionized,  fortunes  would  be 
won,   science  would  advance  years   at  a 


by  Henry  in  America  which  was  capable 
of  lifting  a  ton  weight.  Nowadays  com- 
mercial lifting-magnets  are  made  much 
more  powerful  still. 

The  intimate  relation  between  electricity 
and  magnetism  is  now  well  known,  and  it 


DYNAMO  MADE 
OF  J  RON 


SAME  CAPACITY 
DYJVAMO  MADE  OF 
1R.OH-  COBALT 


The  old  molecular  theory  of  magnetism 

A ,  a,  fl ,  Ar  "-ftr 
irirlrlrlr 

The  new  molecular  theory  of  magnetism  0 


Representation  of  the  Old  and  New  Molecu- 
lar Theories  of  Magnetism. 


to  a  solenoid  or  to  a  permanent  magnet. 
Recently,  however,  strange  things  have 


Comparative  Size  of  Two  Dynamos,  Each  of  Equal  Output,  One 
Made  of  the  Usual  Iron  and  the  Smaller  One  of  the  New  Iron-Co- 
balt Alloy,  Whose  Permeability  Is  25  Per  Cent  Higher  Than  That 
of  Pure  Iron. 


single  bound,  inventions  would  multiply, 
and  warring  nations  might  be  at  once  sub- 
dued. 

Many  attempts  have  been  made  to  solve 
the  problem  of  the  earth's  magnetism  and 
for  the  most  part  these  have  failed  be- 
cause they  presented  nothing  new.  In  fact, 
only  the  most  vague  and  unsatisfactory 
guesses  have  been  possible  concerning  its 
origin,  such  as  that  it  is  due  to  static 
charges  carried  about  by  the  rotation  of 
the  earth,  and  thereby  acting  as  a  magne- 
tizing current ;  or  that  it  was  induced  by 
some  heavenly  body. 

The  earliest  method  of  producing  mag- 
netism was,  of  course,  by  rubbing  with  the 
lodestone  or  natural  magnet.  This  was  a 
slow  way  at  best,  and  magnets  of  great 
strength  were  not  made  until  after  Oersted 
had  discovered  the  magnetic  effects  of  an 
electric  current.  Up  to  this  time  it  has 
scarcely  been  suggested  that  there  was  any 
close  relation  between  electricity  and  mag- 
netism, but  shortly  after  Oersted's  discov- 
ery electro-magnets  of  huge  size  were  con- 
structed, and  we  read  of  one  constructed 


Showing  How  the  Electrons  Revolve  About 
the  Nucleus  In  Opposite  Directions  In  the 
"Non-Magnetic"  Atom. 


was  upon  a  further  study  of  this  intimate 
relation  that  Dr.  Barnett  was  led  to  con- 
clude that  a  bar  of  iron  could  be  magne- 
tized by  simply  rotating  it.  His  results 
show  his  assumptions  to  be  true  and  these 
give  us  many  new  ideas  concerning  the 
nature  of  magnetism  and  even 
suggests  a  totally  new  theory 
concerning  the  magnetism  of 
the  earth  itself. 

The  theory  of  magnetization 
by  rotation,  tho  of  deep  scien- 
tific interest  and  one  which 
reaches  back  to  the  very  struc- 
ture of  matter  itself,  is  not  at 
all  hard  to  understand. 

Everyone  knows  that  a  spin- 
ning top  stands  upright  with- 
out visible  support,  due  to  its 
motion.  In  the  same  way  a 
gyroscope,  which  is  nothing 
more  than  a  wheel  revolving 
about  an  axle,  will  retain  its 
horizontal  position  and  if  dis- 
placed will  return  to  it.  Now 
if  a  bushel  basket  full  of  gyro- 
scopes all  of  them  running, 
was  suddenly  started  revolving, 
all  the  gyroscopes  would  line 
up  with  their  axes  parallel  to 
the  axis  of  rotation  of  the 
basket,  and  all  would  point  in 
the  same  direction.  That  is  the  secret  of 
Magnetization  by  rotation,  only  in  the  case 


Fig.  4 

@ 

Structure  of  the  "Magnetic"  Atom,  Wherein 
the  Electrons  Act  Together. 

of  a  rotating  piece  of  iron,  the  gyroscopes 
are  the  atoms  themselves,  and  because  each 
atom  acts  as  a  little  elemental  magnet ;  when 
they  line  up  the  bar  is  magnetized.  The  only 
{Continued  on  page  355) 


314 


THE  ELECTRICAL  EXPERIMENTER 


September,  1917 


A  Remarkable  Amateur  Radio  Station  with  a  Record 

By  A.  F.  PENDLETON 

Notice  to  All  Radio  Readers 

As  most  of  our  radio  readers  are  undoubtedly  aware,  the  U.  S.  Government  has  decided  that  all  Amateur  Wireless  Sta- 
tions', whether  licensed  or  unlicensed,  or  equip t  for  receiving  or  transmitting ,  shall  be  closed. 

This  is  a  very  important  consideration,  especially  to  those  who  are  readers  of  THE  ELECTRICAL  EXPERIMENTER, 
for  the  reason  that  we  desire  to  continue  to  publish  valuable  articles  on  the  wireless  art  from  time  to  time,  and  zvhich  may  treat 
on  both  transmitting  and  receiving  apparatus.  In  the  first  place,  there  are  a  great  many  students  among  our  readers  who  will 
demand  and  expect  a  continuation  of  the  usual  class  of  Radio  subjects,  which  we  have  published  in  the  past  four  years,  and 
secondly,  there  will  be  hundreds  and  even  thousands  of  new  radio  pupils  in  the  various  naval  and  civilian  schools  thruout 
the  country,  who  will  be  benefited  by  up-to-date  wireless  articles  treating  on  both  the  transmitting  as  well  as  receiving  equip- 
ment.   Remember!  that  you  must  not  connect  up  radio  apparatus  to  any  form  of  antenna. —  The  Editors. 


THE  accompanying  photographs  show 
radio  station  2PM,  owned  and 
operated  by  Messrs.  Faraon  and 
Grinan  of  New  York  City. 
This  station  has  (prior  to  the  war) 
repeatedly  establisht  new  records  for  long- 
distance work.  In  February  they  suc- 
ceeded in  communicating  directly  with  sta- 
tion 9ZF,  in  Denver,  Colo.,  and  a  few 
weeks  later  they  were  reported  being  heard 
in  Los  Angeles,  Calif.,  by  Mr.  J.  B.  Far- 
rington  of  that  city.  To  our  mind  this 
is  wonderful  work,  since  at  no  time  did 
they  use  more  than  450  watts  input.  Their 


from  Seattle,  Wash.,  to  them  via  but  one 
relay  station,  9GC  in  Grand  Forks,  N.  D. 

The  author  recently  made  a  trip  as  oper- 
ator on  the  S.  S.  Manchuria  and  heard 
2PM's  signals  six  days  out.  We  were 
then  2,100  miles  East  of  Nantucket.  The 
author  was  using  a  single  vacuum  valve 
detector. 

Mr.  Lebowitz,  senior  operator  on  the 
S.  S.  Ancon,  has  reported  that  he  heard 
2PM's  signals  while  lying  at  anchor  in 
Colon,  Panama,  on  a  galena  detector. 

Operator  Grace  of  the  S.  S.  El  Sol  and 
Frank  Attwater  of  the  S.  S.  Pastores  have 


Speaking  of  Real  Amateur  Radio  Stations,  Here's 
One  That  Was  Operated  With  Extreme  Success  by 
Messrs.  Faraon  and  Grinan,  in  New  York  City. 
Records,  Did  You  Say?  Well,  They  Were  Heard 
2,100  Miles  Away  by  a  Commercial  Ship  Operator 
on  One  Occasion.  That's  "Class"  on  200  Meters 
and  450  Watts  Input. 


The  efficiency  of  their  installation  should 
be  a  goal  for  all  other  amateurs. 

Mr.  Grinan  operated  old  "N.  Y.",  42 
Broadway,  and  was  also  at  the  Sayville 
trans-Atlantic  station  during  1914.  Mr. 
Faraon  on  a  recent  trip  to  France  oper- 
ated the  Eiffel  Tower  station  in  Paris  for 
seven  months. 

On  February  6th  last,  they  were  the  start- 
ing point  of  the  epoch-making  trans-con- 
tinental message.  It  took  exactly  one  hour 
and  twenty  minutes  for  them  to  receive  an 
answer  to  their  message  addrest  to  6EA 
of  Los  Angeles,  Calif. 

We  know  of  many 
commercial  stations 
that  are  envious  of  the 
records  made  by  these 
men  during  the  past 
I  year. 

Herewith  is  a  list  of 
stations  with  which 
2PM  has  worked  be- 
fore the  war : 


Stations  Worked 


9AAB 

9AAR 

9ABD 

9ALM 

9AU 

9BJ 

9CF 

9DB 

9DC 

9DK 

9EG 

9GJ 

9GY 

9HO 

9IC 

9JI 

9KR 

9AFG 

9LR 

9NN 

9NW 

90N 

9PC 

9PF 

9PI 

9QR 

9RW 

9VY 


by  2PM. 
9WG 
9GC 
9WO 
9XM 
9ZL 
9ZN 
9ZF 

1ASE 

1ASR 

1DK 

1IZ 

1SJ 

1VN 

3AEP 

3AFA 

3AK 

3ATR 

3NB 

3NG 

3PC 

3UF 

3XJ 

3ZS 

3WM 

2AGJ 


wave  length  was  200  meters  and  decrement 
.09,  as  tuned  by  the  radio  inspector. 

During  March  they  handled  400  mes- 
sages, most  of  which  averaged  over  1,000 
miles.    This  also  included  a  message  sent 


both  heard  2PM  while  in  Havana  harbor. 

The  author  visited  their  station  a  num- 
ber of  times  and  noticed  that  the  way  in 
which  they  handled  traffic,  even  thru  the 
worst  kind  of  interference,  was  remarkable. 


U.  S.  SEIZES  POW- 
ERFUL RADIO. 

A  powerful  wireless 
outfit,  valued  at  $10,- 
000,  was  confiscated  re- 
cently and  a  man,  said 
to  be  Edward  Clay,  was 
arrested  by  United  States  secret  service 
agents  about  four  miles  west  of  Green- 
field, O. 

The  secret  service  agents  found  the  ap- 
paratus strung  from  two  big  oak  trees. 


September,  1917 


THE  ELECTRICAL  EXPERIMENTER 


315 


SOUTH  AMERICAN  INDIANS  HAD 
RADIO  IN  1898. 

In  these  days  of  wireless  telegraphy  it 
may  be  interesting  to  learn  that  as  long 
ago  as  July,  1898,  there  was  recorded  the 
discovery  of  a  wireless  telegraphic  appara- 
tus in  use  among  the  Catuquinaru,  an  In- 
dian tribe  of  the  Amazon  valley  in  South 
America,  says  a  writer  in  the  Geographi- 
cal Journal. 

The  apparatus,  called  cambarysu,  con- 
sists of  a  hole  in  the  ground  about  half 
filled  with  coarse  sand;  above  this  layers 
of  fine  sand,  fragments  of  wood  and  bone, 
and  powdered  mica  fill  it  almost  to  the 
surface  of  the  ground.  These  materials 
are  surrounded  by  a  case  of  hard  palm 
wood,  which  extends  above  the  surface. 
The  upper  part  of  the  apparatus  consists 
of  layers  of  hide,  wood  and  hard  rubber, 
arranged  in  the  manner  shown  in  the  ac- 
companying illustration  below. 

Between  the  upper  layers  and  the  lower 
layers  there  is  a  hollow  space.  With  a 
club,  much  like  the  stick  used  to  play  the 
bass  drum,  the  native  strikes  the  layer  of 
rubber  that  forms  the  top  of  the  instru- 
ment. 

One  of  these  instruments  is  concealed 
in  each  hamlet  of  the  tribe.  The  villages 
are  not  more  than  a  mile  apart,  and  are 
placed  in  a  direct  North-and-South  line. 
Altho  a  person  standing  outside  the  build- 
ing in  which  the  apparatus  is  kept  can- 
not hear  a  blow  of  the  stick  on  the  rubber 
top,  it  is  quite  distinct  in  a  similar  build- 
ing a  mile  distant.  When  one  of  these  in- 
struments is  struck,  the  neighboring  ones 
to  the  North  and  South  echo  the  blow. 
The  Indian  stationed  at  each  one  of  the 
posts  answers  the  signal,  and  by  means  of 
code  messages  a  long  conversation  may  be 
carried  on. 


PUEBLO,  COLO.,  NAVY  STAFF 
STARTS  RADIO  SCHOOL. 

Spurred  by  the  need  of  the  navy  for  sev- 
eral thousand  radio  operators,  members  of 
the  Pueblo  naval  recruiting  staff  have,  of 


SENATOR  MARCONI  ENCOUR- 
AGES WOMEN'S  WIRELESS 
CLASS. 

The  accompanying  photograph  shows  the 
women's  wireless  class  of  Hunter  College, 


An  electrical  process  is  being  tried  in 
Russia  for  the  manufacture  of  gold  leaf, 
heretofore  made  only  by  hand. 


New  York  City,  and  Senator  Marconi  of 
the  Italian  Commission  in  a  special  pose  at 
the  Hotel  Ritz-Carlton,  where  the  Senator 
received  the  girls. 

The  women  are  studying  to  become  radio 
operators  for  the  Government.  The  class 
was  organized  before  the  war  was  declared 
and  now  has  one  hundred  and  twenty-five 
women  enrolled.  The  students  are  now 
taking  tine  more  intensive  course  at  the 
Marconi  School.  Senator  Marconi  talked 
to  the  women  on  their  work  as  an  aid  to 
the  Government  in  war  time. 


As  Far  Back  As  1898,  the  South  American  Natives  Had  a  Sys- 
tem of  "Wireless   Communication"   Working.     It   Employed  S,ve  tlle  instruction  an  ap- 
Sound  Waves  Propagated  Thru  the  Earth.  plicant  needs  to  qualify  for 


Photo  Qby  Unieruooi  4  Un.lerwood 

Senator  Guglielmo  Marconi  on  His  Recent  Visit  to  New  York  and  the  Young  Women  Radio 
Siuucnts  01  nunier  Ouiicye  to  Wnom  i-ic  Gave  Important  Advice  as  to  the  Future,  as  Well 
as  the   Military   Advantages   of  Radio-Telegraphy. 

their  own  initiative,  arranged  to  start  a 
school  in  wireless  telegraphy.  Classes  will 
be  held  at  the  naval  recruiting  headquarters 
starting  very  soon.  Charles  T.  Randall, 
head  of  the  station,  and  H.  T..Rainey. 
one  of  his  assistants — both  men  graduates 
of  the  U.  S.  naval  radio  service  course  at 
Mare  Island  near  San  Francisco — will  be 
the  instructors. 

The  course  will  be  free 
of  charge.  It  will  be  open 
to  young  men  between  the 
ages  of  18  and  25  years,  tho 
in  special  cases  men  up  to 
30  years  of  age  and  ap- 
proaching 18  will  be  accepted. 

The  navy  is  now  in  urgent 
need  of  wireless  operators. 
Every  ship  which  crosses  the 
\tlantic  now  must  be  pro- 
vided with  them.  The  great 
nerchant  fleet  of  1,000  ships 
being  built  by  the  United 
States  Government  to  beat 
die  German  submarine 
>lockade  must  be  supplied 
vith  naval  radio  operators 
ind  gunners.  In  addition 
here  are  some  300  subma- 
rine chasers  which  will  have 
o  be  supplied  with  operators 
>y  fall.  Many  ships  of 
various  other  kinds  are  now 
n  the  service  or  will  be 
olaced  in  the  service  in  the 
ar  future. 

All  of  these  must  have 
laval  radio  operators. 

The  men  who  may  be  en- 
-olled  as  landsmen  for  elec- 
trician (radio  operators) 
nust  be  able  to  receive  at 
'east  ten  words  a  minute  in 
the  continental  code  legibly, 
;pell  correctly  at  the  rate  of 
IS  words  per  minute  and 
lave  a  grammar  school 
knowledge  of  arithmetic. 
Randall  and  Rainey  will 


enlistment  as  an  operator.  They  estimate 
that  the  average  man  should  master  this  end 
of  it  inside  of  three  weeks.  Then,  if  he 
qualifies  for  enlistment  in  other  regards, 
he  will  be  sent  on  to  one  of  the  three  train- 
ing schools  for  wireless  operators — Har- 
vard, Mare  Island,  or  the  New  York  school 
in  the  Brooklyn  navy  yard. 

Three  of  four  months'  training  should 
make  a  man  able  to  handle  an  instrument  in 
the  naval  service.  Thus,  inside  of  three  or 
four  months,  a  man  should  be  able  to  get 
into  actual  service  on  some  craft  of  the 
United  States  navy.  He  might  be  detailed 
to  a  submarine  chaser  and  go  thru  with  the 
tense  excitement  of  hunting  out  the  German 
sea  sharks  off  the  British  Isles  or  the  coast 
of  France.  Or  he  might  be  put  on  one  of 
the  great  merchant  fleet  ships  which  will 
run  the  submarine  gauntlet.  Or  again  be 
assigned  to  one  of  the  U.  S.  battleships. 

In  addition  to  affording  a  chance  for  all 
kinds  of  wild  adventure  in  the  radio  service 
inside  of  a  short  time,  it  is  one  of  the  most 
desirable  branches  of  the  naval  service,  all 
of  the  grubby  and  disagreeable  work  which 
falls  to  the  lot  of  an  ordinary  seaman  being 
eliminated. 

The  radio  operators,  third  class,  will  re- 
ceive $32.60  per  month  and  all  expenses ; 
second  class,  $52,  and  first  $61. 


316 


THE  ELECTRICAL  EXPERIMENTER 


September,  1917 


U.  S.  SIGNAL  CORPS  WANTS  ELEC- 
TRICAL AND  RADIO  MEN. 

Still  the  cry  comes  for  more  men !  You 
young  fellows  hanging  on  the  outside  of 
things  in  these  stirring  days  don't  seem  to 


DeFOREST    LOSES  "AMPLIFIER" 
AND  POSSIBLY  "OSCILLION" 
PATENTS. 

Judge  Julius  M.  Mayer  found  the  follow- 
ing on  July  11,  for  the  Marconi  Company, 
plaintiff,  against 
the  de  Forest 
Radio  Telephone 
and  Telegraph 
Company,  de- 
fendant : 

"This  is  the  re- 
turn of  an  order 
to  show  cause 
why  the  decree 
and  injunction 
heretofore  made 
and  issued  does 
not  cover  and  in- 
clude certain  de- 
vices which  de- 
fendant makes 
and  sells  and  why 
the  reports  al- 
ready filed  should 
not  be  extended 
to   include  such 


At  the  Right  We  See  a 
New  York  Street  Exhibit 
Where  the  Omnlgraph 
Clicks  Off  the  Dots  and 
Dashes  to  Future  Sol- 
diers. 


"1.  An  amplifier  consists  really  of  two 
or  more  detectors  in  tandem  with  a  tele- 
phone transformer  interposed  between  each 
element  of  the  series.  The  primary  ele- 
ment of  such  an  amplifier  may  be  either 
an  Audion  or  any  other  form  of  detec- 
tor. In  some  of  the  amplifier  sets  sold 
by  defendant,  the  primary  element  is  a 
part  of  the  outfit.  In  other  instances,  the 
primary  element  is  not  part  of  the  outfit. 

"I  fully  agree  with  Waterman  on  his 
facts  and  explanation  as  to  the  'ampli- 
fier'. In  other  words,  an  'amplifier'  is  part 
of  a  detector.  In  any  event,  the  case  falls 
under  the  familiar  rule  of  Roberts  v.  Ryer, 
91  U.  S.  150,  157,  many  times  since  reiter- 
ated and  followed.  I  have  no  doubt  what- 
ever that  the  motion  in  this  regard  must 
be  granted. 

"2.    I  am  not  clearly  convinced  that  the 
Fleming  valve  can  perform  the  functions 
of  an  'oscillion'  so  as  to  oscillate  and  gen- 
erate radio  waves.    On  this  branch  it  will 
be  necessary  to  give  demonstrations  or  oral 
testimony  or  both  and  witnesses  should  be 
subject  to  cross-examination.  This  is  really 
equivalent  to  a  trial.  My  view  is  that  where 
the  court  on  an  application  of  this 
kind  is  not  clearly  convinced  that 
the  motion  should  be  granted,  then 
the  proceeding  should  be  by  bill 
and   answer,   because  _  the  inquiry 
necessarily  develops  into  a  trial, 
and,  therefore,  the  issues  should  be 
clearly  joined.     There  is  usually 
little  saving  of  time  or  labor  in  short 
cuts. 

"The   motion,   therefore,   as  to 
'oscillions'  is  denied." 


grasp  the  opportunities 
that  are  being  offered  you 
in  the  U.  S.  Signal  Corps. 

The  Signal  Corps  needs 
men  and  needs  them 
badly,  so  if  you  are  qual- 
ified in  any  branch  of  the 
work  just  step  up  and  be 
one  of  the  boys  to  "do 
your  bit." 

A  large  school  has  been  opened  at  Pratt 
Institute,  Brooklyn,  to  give  training  to 
young  men  in  Radio  work,  and  all  men 
enlisting  are  immediately  transferred  there 
to  receive  a  complete  course  in  Radio  Teleg- 
raphy. 

The  Corps  is  using  many  interesting  and 
novel  ways  of  street  advertising  and  two 
illustrations  are  here  reproduced  showing 
some  of  these  stunts.  The  field  radio  pack 
set  is  on  exhibition  at  Times  Square,  New 
York  City,  and  is  drawing  quite  a  number 
of  worthy  lads  to  the  service.  Recruiting 
offices  have  been  opened  all  over  the  coun- 
try for  this  branch  of  the  service,  includ- 
ing New  York,  Philadelphia,  Rochester, 
Baltimore,  Richmond,  Ithaca  (where  aero- 
nautics is  taken  up  with  this  work)  and 
Pittsburgh. 

One  of  our  illustrations  depicts  an  omni- 
graph  attached  to  a  small  electric  lamp 
bulb.  The  telegraphic  flashing  off  and  on 
always  draws  a  big  crowd  of  men  and  boys, 
who  gasp  in  astonishment  at  the  unfamiliar 
signaling  apparatus. 

As  soon  as  a  bystander  manifests  the 
slightest  interest  and  starts  asking  ques- 
tions, one  of  Uncle  Sam's  smart  khaki  clad 
soldiers  gets  busy  and  explains  the  many 
advantages  of  the  service  to  him. 

The  main  offices  for  the  Eastern  Divi- 
sion are  at  39  Whitehall  street,  New  York, 
and  all  communications  and  inquiries  should 
be  addrest  to  Major  Henry  G.  Opdycke, 
who  is  in  charge  of  recruiting  in  New  York 
City  and  vicinity. 

It's  up  to  you,  so  show  your  colors ! 


devices. 

"The  devices  in  question  are  called 
'amplifiers'  and  'oscillions.' 

"In  the  first  place,  this  procedure  is  cor- 
rect. It  has  frequently  been  followed  in 
this  court  and,  as  I  understand,  approved 
by  the  Circuit  Court  of  Appeals. 

"The  opinions  of  the  Circuit  Court  of 
Appeals  and  of  this  court  on  the  main  con- 
troversy so  fully 
discust  the  essen- 
tial features  of  the 
patent  and  the  in- 
fringing  device 
that  it  must  be  as- 
sumed that  the 
litigants  are,  by 
this  time,  fully  in- 
formed  of  the 
views  of  the  two 
courts.  As  in  the 
original  case,  there 
is  again  the  use  of 
'Audion'  language, 
which  is  more  or 
less  meaningless 
from  the  stand- 
point of  the  patent 
law  and  certainly 
does  not  add  to  a 
clear  understand- 
ing of  what  has 
now  become  rea- 
sonably simple, 
even  in  an  ab- 
struse art. 


A    FRENCH    RADIO  CON- 
TROLLED TORPEDO. 
By  Frank  C.  Perkins. 

The  accompanying  illustration 
shows  a  remarkable  French  auto- 
matic wirelessly  controlled  torpedo 
on  the  River  Seine.  The  control  of 
this  torpedo  from  a  distance  is  ac- 
complish by  a  wireless  operated 
valve  supplying  comprest  air  to  the 
motor.  To  turn  the  torpedo  one 
way  or  the  other  the  rudder  is  moved 
by  two  solenoids  controlling  the  air 
valve  by  means  of  different  wave 
lengths.  To  steer  the  torpedo  to  the  right 
one  set  of  wave  lengths  are  used,  the  coherer 
acting  on  the  proper  solenoid  and  operating 
the  air  valve  turning  the  rudder  in  that  di- 
rection. To  turn  the  rudder  so  as  to  swing 
the  torpedo  to  the  left,  another  similar  mech- 
anism is  used  which  works  on  another  wave 
length.  At  the  wireless  controlling  station 
there  is  checking  and  tally  apparatus. 


A  French  Radio-Controlled  Torpedo.    Such  Devices  as  These,  If  Made 
to  Resist  Enemy  Radio  Interference,  May  Prove  One  of  the  Deciding 
Factors  In  the  World  War. 


September,  1917 


THE  ELECTRICAL  EXPERIMENTER 


317 


PORTABLE   WIRELESS  REPORTS 
CALIFORNIA  "WASH-OUTS." 
By  Charles  W.  Geiger. 

During  the  annual  rainy  season  in  South- 
ern California,  a  wireless  outfit  is  sent  out 
in  all  directions  to  report  the  condition 
of  the  roads  and 
various  bridges  that 
may  have  been 
washed  out. 

The  wireless  outfit 
is  mounted  on  a 
1^2-ton  motor  truck. 
The  equipment  con- 
sists of  field  tele- 
phones, switch- 
boards,  relay  coils, 
guys,  metal  pins, 
aerial  and  demount- 
able poles,  head  sets, 
telegraph  keys  and 
other  equipment. 
The  truck  made  30 
miles  an  hour  on 
good  roads.  It  car- 
ried a  company  of 
15  men.  The  follow- 
ing is  a  copy  of  a 
wireless  report  from 
the  expedition : 
"Roads  open  Bakers- 
field  Castaic  Wash 
quick  sand  danger- 
ous cars  sinking  to 
frame  passable 
towed  county  team 
Ridge  route  passable 
from  end  State  high- 
way to  Castaic  rough 
dangerous  Bakers- 
field  reached  Bou- 
quet canyon  Elisa- 
beth lake  rough 
thruout  deep  ruts 
bogs  Mint  closed 
(Signed) ." 


MISS  SYDNEY  SHIELDS,  WIRE- 
LESS OPERATOR. 

Miss  Sydney  Shields,  the  little  leading 
woman  who  was  recently  seen  in  "The  Case 
of  Lady  Camber,"  is  the  very  first  woman 
of  the  stage  to  have  completed  a  wireless 


telegraphic  course.  She  is  now  ready  to 
enlist  in  the  Signal  Corps  of  the  United 
States  Navy.  Wanting  to  be  especially 
efficient  in  the  field  she  has  chosen  to  serve 
her  country,  Miss  Shields  has  taken  a  post- 
graduate course  in  the  various  other  ways 
of  marine  signaling 
— by  means  of  flags 
and  semaphores, 
Ardois  lights  and 
"blinkers."  Just  now 
she  is  intensely  in- 
terested in  the  new 
means  of  communi- 
cating on  the  high 
seas  with  "smoke 
signals,"  which  are 
electrically  operated, 
according  to  the 
Morse  code. 

"Although  it  may 
seem  wicked  to  say 
so,"  said  Miss 
Shields,  "I  have 
never  had  such  a 
good  time  as  since 
war  was  declared. 
When  I  was  a 
youngster  my  great- 
est regret  was  be- 
cause I  was  a  girl 
instead  of  a  boy.  I 
wanted  to  be  a  sai- 
lor." 


In  California  They  Have  Developed  a  New  Use  for  the  Radio.    During  the  Rainy  Season  a 
Portable  Radio  Outfit  Is  Sent  Out  to  Report  the  Road  Conditions. 


A  high  barbed 
wire  fence  now  sur- 
rounds the  United 
States  radio  station 
at  North  Head, 
Wash.,  and  the 
strands  of  wire  are 
heavily  charged  with 
high  -  tension  elec- 
tricity. 


The  Present  Status  of  the  Audion 


NOW  that  the  U.  S.  Circuit  Court 
of  Appeals  has  refused  to  reverse 
the  lower  Court's  finding  that  the 
Audion  is  an  infringement  of  two 
claims  of  the  Fleming  Valve  pat- 
ent, a  brief  review  of  the  facts  brought  out 
in  the  trial  will  be  of  interest  to  all  radio 
men. 

First  of  all  it  was  shown  that  both  Flem- 
ing and  de  Forest  utilized  the  Edison  effect, 
or  the  incandescent  lamp  with  a  cold  elec- 
trode—Fleming as  a  rectifier  simply  and 
solely,  connecting  the  cold  electrode,  always 
and  invariably,  to  the  negative  of  the  fila- 
ment battery ;  that  this  rectifier  was  in- 
ferior to  any  ordinary  crystal  rectifier,  and 
has  never  been  used  in  commercial  wire- 
less signaling;  incidentally  that  Fleming 
claimed  in  his  patent  that  he  had  discovered 
this  rectification  phenomenon,  quite  forget- 
ful of  Edison,  Howell,  Wehnelt,  etc.  Fur- 
ther, that  de  Forest  was  the  first  to  dis- 
close the  use  as  a  wireless  detector  of  the 
heated  electrode  in  gas — at  atmospheric  or 
rarefield  pressure ;  that  by  the  addition  of 
the  B-battery  in  the  telephone  circuit  a 
genuine  relay  (as  distinguished  from  the 
rectifier)  effect  was  obtained,  of  much 
greater  sensitiveness ;  that  two  years  after 
de  Forest's  disclosure  of  the  Edison  lamp 
relay  detector  with  B-battery,  Fleming  rec- 
ognized the  new  way  as  he  styled  it,  in 
which  this  incandescent  lamp  detector  can 
be  used,  and  patented  a  form  of  B-battery 
"valve"  of  which  some  200  were  used ; 
that  long  prior  to  this  "discovery"  de  Forest 
had  introduced  the  third,  or  grid  electrode, 
which  at  once  placed  the  Audion  in  a  class 
by  itself;  that  this  grid  principle  and  nu- 
merous improvements  which  de  Forest  and 


By  Dr.  LEE  de  FOREST 

other  inventors  had  brought  out  from  time 
to  time  had  made  possible  the  reliable 
trans-oceanic  telegraphy,  trans-continental 
telephony  (wire  and  wireless),  the  Audion 
Amplifier  of  low  and  high-frequency  cur- 
rents, the  Ultraudion,  or  self-heterodyning 
detector,  the  Oscillion  or  generator  of  un- 
damped waves  of  any  length ;  that  tens  of 
thousands  of  grid  Audions  have  been,  and 
are  in  use  by  every  Government  in  the 
world ;  that  the  present  state  of  our  U.  S. 
Navy  Radio  Service,  and  of  the  Radio 
Art  itself,  could  not  exist  without  the 
Audion;  that  the  Fleming  valve  (as  dis- 
closed in  his  U.  S.  and  Foreign  patents), 
had  contributed  nothing  whatever  of  utility 
to  the  art,  and  has  evolved  not  at  all ;  that 
the  rectification  effect  on  which  the  valve 
must  absolutely  depend  (ceases)  when  both 
electrodes  are  heated ;  that  the  Audion  ef- 
fect on  the  other  hand  is  unaffected  whether 
one,  two  or  three  electrodes  are  incandes- 
cent; that  any  rectification  effect,  if  ex- 
istent at  all,  is  wholly  parasitic  and  of  no 
effect  in  the  genuine  relay  and  extraordi- 
narily sensitive  actions  which  make  the 
Audion  so  immensely  practical. 

However,  and  largely  due  to  the  clever 
and  fact-defying  feats  of  the  Marconi  ex- 
pert, all  the  above  considerations  availed 
nothing  to  convince  the  Court  that  a  very 
great  injustice  would  be  inflicted  by  grant- 
ing to  the  inutile  Fleming  patent,  domina- 
tion over  what  all  unbiased  scientific  minds 
the  world  over  have  come  to  regard  as 
one  of  the  most  radical  and  practically  valu- 
able devices  yet  discovered  in  the  art  of 
signaling,  by  wire  or  wireless.  Truly — - 
"the  Shadow  dominates  the  Substance." 

This  Audion  patent  case  is  on  all  fours 


with  that  of  the  famous  Selden  automobile 
patent,  but  with  this  immense  difference: 
the  Court  there,  while  finally  sustaining  the 
visionary  and  impractical  Selden  patent  as 
basic,  so  limited  its  applications  that  its 
owners  were  no  longer  able  to  extort  tribute 
from  those  who  had  actually  developed 
the  gasoline-engine-propelled  vehicle  of 
commerce. 

Early  in  the  Audion  trial  the  Marconi 
Wireless  Telegraph  Company  confest  the 
validity  and  their  infringement  of  the  de 
Forest  grid  and  amplifier  Audion  patents, 
and  are  now  perpetually  enjoined  from 
these  patents.  They  are  at  present  en- 
deavoring to  avoid  this  hardship  by  de- 
veloping an  Audion  with  the  grid  member 
on  the  outside  of  the  glass,  in  defiance  of 
the  de  Forest  Patent  No.  841,386;  but  due 
to  the  present  inferiority  in  sensitiveness 
of  this  to  the  interior  grid  Audion,  they 
have  not  yet  used  the  device  in  practise. 
They  were  also  forced  to  file  a  disclaimer 
in  the  Patent  Office,  limiting  their  claims 
to  high-frequency  currents — as  otherwise 
all  their  claims  were  invalid  on  their  face, 
in  view  of  Edison.  For  ten  years  those 
claims  have  thus  stood  obviously  invalid 
and  un-menacing  to  a  rapidly  developing 
Audion  art. 

To  those  familiar  with  U.  S.  Courts  of 
Appeals  in  patent  causes,  the  recent  sus- 
taining of  the  Lower  Court's  finding  in 
so  highly  technical  a  case  detracts  nothing 
from  the  true  merits  of  the  Audion  as 
against  the  "valve."  It  is  the  consensus 
of  unbiased  opinion  of  those  acquainted 
with  the  facts  that  an  opportunity  to  correct 
a  grievous  injustice  has  been  regrettably 
lost  bv  this  court. 


3'8  THE  ELECTRICAL  EXPERIMENTER  September,  1917 

"Radio"- Communication  Over  Gas  and  Water  Pipes— "Wired  Wireless" 

I      f/fy/'^  J,ave  ^ecn  careful  in  studying  the  various  phases  embodied  in  this  article,  and  it  is  our  opinion  that  amateurs  may  now  t 

|     yfS     find  a  good  as  well  as  practical  use  for  their  outfits.   Let  it  be  understood  that  the  ideas  set  forth  in  this  article,  do  in  no  1 

way  violate  the  President's  order,  as  no  radio  waves  are  either  radiated  in  free  space  {ether),  nor  can  outside  radio  mes-  I 

I    sages  be  received  with  such  outfits.    From  this  it  follows  that  "Wired  Wireless"  is  nothing  but  a  modified  telegraph  wire  line.  I 

1     The  "wire"  in  this  instance  being  the  gas  or  water  mains.  % 

By  means  of  this  system,  amateurs  should  be  enabled  to  cover  modest  distances  by  relaying  messages  from  house  to  house  1 

m  block  to  block.    This  should  keep  them  in  trim  until  such  time  when  we  will  be  allowed  to  send  and  receive  real  radio  I 


or  fro 
messages 


T 


ident. 


HE  radio  amateur  has  undoubtedly 
in  many  instances  felt  that  all  was 
lost  after  amateur  and  experimental 
radio  stations  thruout  the  country 
had  been  closed  by  order  of  the  Pres- 
In  the  following  paragraphs  there 


general  is  to  utilize  the  ordinary  buzzer, 
such  as  commonly  used  for  signaling  pur- 
poses in  place  of  bells,  etc.,  as  the  reader 
will  perceive  from  the  diagrams  here  given. 

Referring  first  to  the  sending  circuits, 
an  ordinary  buzzer  is  utilized  thruout  in 


ture  terminals  of  the  buzzer,  interposing 
a  small  fixt  condenser  in  series  with  one 
of  these  leads  to  prevent  short-circuiting 
the  buzzer  coils.  This  is  a  more  efficient 
type  of  transmitter  than  that  shown  in 
Fig.  1. 


"Radio-bugs"  Who  Are  Grieving  Their  Hearts  Away  Because  They  Cannot  Use  Their  Radio  Apparatus,  Will  Find  This  Group  of  Short-range 
"Wired  Wireless"  Hook-ups  of  Interest.    A  Buzzer  Transmitter  Is  Employed  and  a  "Unilateral"  Receptor. 


are  given  a  number  of  new  ideas  which  it 
is  believed  the  radio  amateur  will  find  of 
considerable  interest  under  the  present 
stringent  conditions  governing  all  such 
work. 

The  general  scheme  here  outlined  is  to 
carry  on  short-range  communication  by 
means  of  radio  apparatus  of  extremely 
low  power,  and  with  which  it  is  not  pos- 
sible to  transmit  or  receive  messages  over 
a  distance  exceeding  a  few  city  blocks  or 
possibly  one-quarter  of  a  mile. 

The  circuits  shown  are  presented  in  three 
different  groups  under  "Transmitting," 
"Receiving,"  and  "Combined  Transmitting 
and   Receiving  Hook-ups."     The   idea  in 


Figs.  1  to  4.  In  Fig.  1,  there  is  shown  a 
low-power  buzzer  transmitter,  a  connec- 
tion being  establisht  between  the  water 
pipe  (or  a  piece  of  pipe  or  other  metal 
driven  into  the  damp  earth)  as  indicated. 
This  connection  being  known  as  unilateral 
excitation.  It  should  be  used  wherever  a 
short  distance  of  a  few  hundred  feet  is 
to  be  covered,  so  as  to  not  create  any  un- 
due disturbance  or  interference  with  other 
stations  which  may  be  using  a  similar 
transmitter. 

The  buzzer  transmitter  shown  in  Fig.  2 
represents  a  bipolar  transmitter,  connec- 
tions being  establisht  between  the  gas  and 
water  pipes  to  the  contact  screw  and  arma- 


Diagram  Fig.  3  shows  a  bipolar  buzzer 
transmitter,  connected  to  the  gas  and  water 
pipes  with  a  fixt  condenser  in  series  with 
one  of  the  leads,  and  also  utilizing  an  extra 
kicking  inductance  in  one  of  the  exciting 
leads.  This  inductance  may  consist  of  a 
soft  iron  wire  core,  about  24  mcn  >n 
diameter  by  6  inches  long,  wound  with 
several  layers  of  No.  16  insulated  magnet 
wire.  The  inductance  coil  tends  to  intensify 
the  radiated  current  by  the  self-inductance 
action  of  the  coil  and  iron  core.  Fig.  4 
shows  a  unilateral  connection  of  buzzer 
with  inductance  coil. 

{Continued  on  page  332) 


September,  1917 


THE  ELECTRICAL  EXPERIMENTER 


319 


A  CONTROL  HANDLE  FOR 
UNDAMPED  WAVE  TUNERS. 

In  the  handling  of  super-sensitive  un- 
damped wave  apparatus,  the  operator  is  put 
to  a  great  deal  of  inconvenience  by  the  fact 
that  the  proximity  of  his  hand  to  the  appa- 
ratus has  a  marked  effect  upon  the  opera- 
tion. 


nograph  to  receive  undamped  waves.  Where 
no  motor  is  available  to  drive  the  tikker, 
cut  out  a  metal  disc  about  \0l/z  inches  in 
diameter,  having  nicks  evenly  spaced  about 
the  circumference,  ]/$  inch  apart.  When 
the  phonograph  is  not  otherwise  engaged, 
put  on  this  new  record  and  use  it  as  a  cir- 
cuit-breaker in  place  of  the  ordinary  crys- 
tal detector  in  the  receiving  circuit,  'fry 
it — it  works  !  ! 
Contributed  by       F.  C.  HAMILTON. 


with  as  mu^h  or  even  greater  separation 
between  points  than  is  usually  allowed. 

The  template  is  a  lather  thick  piece  of 
metal.    The  stud  for  tne  center  hole  of  the 


To    Prevent    "Body"    Capacity  Interfering 
With   Undamped  Wave  Audion  Tuning  Use 
May  be  Made  of  This  Extension  Handle. 

To  overcome  this  annoying  and  time  con- 
suming condition,  there  is  a  scheme  where- 
by the  knobs  of  the  control  are  extended  as 
far  from  the  set  as  is  necessary  to  keep  the 
operation  of  the  set  stable.  This  plan,  while 
effective,  disfigures  a 
neat  appearing  set, 
and  takes  up  valuable 
room. 

To  secure  the  ad- 
vantages of  the  above 
plan,  at  the  same  time 
doing  away  with  the 
disadvantages,  the 
author  devised  the 
controller  shown  in 
the  sketch,  which  is 
self-explanatory.  The 
entire  device  should 
be  made  of  Bakelite, 
hard  rubber  or  fiber, 
with  the  exception  of 
the  pins,  which  may 
be  of  brass.  The 
knobs  of  the  set  have 
two  small  holes 
drilled  in  them  to  receive  the  pins.  These 
holes  need  not  be  very  deep,  and  will  not 
mar  the  appearance  of  the  apparatus  in 
the  least. 

In  operation  the  device  is  used  for  fine 
or  close  adjustments.  The  set  is  roughly 
tuned  to  the  incoming  wave  in  the  usual 
manner.  Upon  removing  the  hand,  the  sig- 
nals often  die  completely  out.  Then  by 
using  the  controller,  the  signals  are  brought 
back  to  their  original  loudness. 

The  hard  rubber  rod  should  be  not  less 
than  twelve  inches  long.  With  some  sets 
two  feet  may  be  necessary. 

Contributed  by       C.  S.  ROBINSON. 

TRY  THIS  ON  YOUR  "VICTROLA." 

Most  of  "us  amateurs"  who  are  still  with- 
out Audions  can  make  use  of  their  pet  pho- 


AN  EFFICIENT  SCHEME  FOR 
LEARNING  THE  CODE. 

To  learn  the  code  well,  altho  not  dif- 
ficult, requires  considerable  and  attentive 
practise.  Very  often  the  beginner  claims 
he  knows  the  code  well,  giving  as  proof  his 
ability  to  send.  The  proof,  however, 
should  be  his  ability  to  receive  well  and  the 
impatient  learner  usually  fails  in  this  at- 
tempt. Confusion,  the  cause  of  this,  is  the 
result  of  the  incoming  signals  not  being 
imprest  sufficiently  upon  his  memory  to  re- 
spond quickly.  His  efforts  should  there- 
fore be  directed  to  methods  more  suitable 
than  the  ordinary  sound  signals. 

Referring  to  the  accompanying  sketch, 
the  lead  wires  lettered  "to  phone"  are  taken 
from  the  stationary  contact  and  armature 
of  the  ordinary  buzzer.  In  series  with  the 
buzzer  is  a  small  electric  bulb  of  the  flash- 


\C.TOn 


rare  14    6  Or'/S 

Dr/// sizes  for  /4  c/se  f5/dr///  for  f>6  use 
fssjn//  far  *  >t  Lse  *ss  dr/// 


® 


With  the  Arrangemen 
on 


t  of  Lamps  and  Buzzers  Shown,  the  Telegraph 
the  Student's  Mind  Both  Visually  and  Aura 

light  type.  By  enclosing  the  light  in  a  small 
box  which  supports  in  front  of  it  a  small 
transparent  screen  of  a  gray  color,  the  per- 
sistence of  vision  on  the  retina  of  the  eye 
will  not  be  effective  to  such  a  degree  as  to 
interfere  with  the  proper  reception  of  sig- 
nals. The  buzzer  should  be  adjusted  to  a 
high  pitch  and  packed  in  a  box  with  cot- 
ton. Four  dry  cells,  two  at  each  end  of 
the  line,  will  provide  current  enough  for 
several  hundred  feet.  The  operation  of  the 
line  is  as  follows : 

When  receiving,  the  beginner  should  look 
attentively  at  the  gray  screen  in  front  of 
the  electric  bulb.  The  receiver  should  be 
held  on  his  ear  by  the  customary  head-band 
and  may  be  of  the  seventy-five  ohm  type. 
When  the  key  is  deprest  at  the  other  end,  he 
will  not  be  confused,  as  the  light  and  buz- 
zer will  act  simultaneously  in  their  action 
on  his  mind  in  the  same  manner  that  per- 
sons speaking  naturally  convey  their  mean- 
ing by  facial  expression  and  words,  the  two 
always  acting  in  harmony.  By  means  of 
the  cut-out  switches  shown,  any  one  of  the 
instruments  at  either  end  of  the  line  may 
be  used. 

Contributed  by         JOSEPH  BRAFF. 


This  Scheme  Proves  That  There   Is  a  Way 
to    Get    an    Unusually    Large    Number  of 
Switch   Contacts   In   a   Small  Space. 

switch  is  soldered  fast  to  it.  and  three  holes, 
of  the  size  given  for  the  different  sizes  of 
wire,  drilled  in  the 
outer  end.  In  mak- 
ing a  switch,  the  stud 
is  inserted  in  the  cen- 
tral hole  of  the  base 
and  the  first  hole 
drilled.  Put  a  pin  (a 
phonograph  needle) 
through  the  template 
into  the  base  in  this 
hole  and  drill  the 
next  pair.  Then  move 
the  template  so  that 
the  pin  will  enter  the 
outer  hole  of  the  pair 
just  drilled,  and  drill 
the  next  pair;  con- 
tinuing in  this  man- 
ner until  the  required 
number  have  been  fin- 
ished. 

This  method  insures  a  true,  evenly  spaced 
switch,  without  use  of  dividers,  or  laying 
out  the  switch  base,  marking  it  off,  etc  and 
when  carefully  made  the  switch  is  a 'neat 
and  very  efficient  article.  Enameled  wire 
may  be  used  for  the  points,  and  cleaned  of? 
on  top  with  sand  or  emery  paper,  after  the 
switch  is  finished.  The  wire  is  best  twisted 
several  times  on  the  back  of  the  base  or 
panel,  so  as  to  ensure  its  remaining  in  place 
permanently.  Tap  leads  from  coils  may 
be  soldered  to  the  twisted  wire  stubs.  The 
idea  is  very  useful  in  building  miniature 
loose  couplers. 

Contributed  by  CEP 

RADIO  STATION  CHART  FOR 
TUNING  DATA. 

The  chart  here  shown  will  prove  useful 
m  any  wireless  station  for  keeping  a  record 
of  the  setting  of  the  instruments.  It  saves 
time  and  patience,  as  one  can  tune  any  sta- 
tion on  the  minute  providing  it  is  recorded 


ic  Signals  Are  Imprest 
My. 


A  Toothed  Metal  Disc  Driven  By  a  Phono- 
graph   Motor  So   As  to  Interrupt  the  Con- 
denser Circuit  Rapidly  Provides  a  Serviceable 
"Tikker." 


PLACING    LARGE    NUMBER  OF. 
SWITCH   POINTS  IN  SMALL 
SPACE. 

For  use  where  a  large  number  of  switch 
points  are  necessary  in  a  small  space,  or 
where  the  regular  switch  points  are  geo- 
graphically or  financially  out  of  reach,  this 
switch  is  recommended.  Forty-eight  of 
these  points  can  be  put  in  a  two-inch  circle 


  .  

Slot /on  Chart 

Station 

Coil 

WHnqh 

Time 

Prim 

Sec 

Coup 

Cm 

L  i 

iri/ngton 

//A  A 

.  -,;>«.  v<  ■ 

Continuous 

s  points 

*  points 

-><>' 

0 

Brooklyn 

tltAfi. 

io oo  etc 

//.JO 

j  • 

3  - 

JO* 

3 pot/A 

LOUfrSfiOrp 

Vauen-G 

PO.Z 

12000 

1030  PM 

10  " 

6  • 

soc 

fS  • 

Undamped 

Radio  Operators  Will  Find  This  Method  of 
Keeping    Station    Data    Very    Efficient  for 
Rapid  Tuning. 

on  the  chart.    Such  a  chart  will  also  show 
how  far  you  can  receive. 
Contributed  by 

MAURICE  L.  MUHLEMAN. 


320  THE  ELECTRICAL  EXPERIMENTER  September,  1917 

Calculation  and  Measurement  of  Inductance 


By  H.  WINFIELD  SECOR  AND  SAMUEL  COHEN 


Part  3  (Conclusion)* 

HAVING  thoroly  discust  the  meth- 
ods of  both  calculating  and  meas- 
uring the  inductance  of  coils,  we 
are  now  in  a  position  to  continue 
with  the  design  of  the  most  im- 
portant type  of  inductance  coils  used  in 
radio  work.  We  will  confine  ourselves  to 
the  types  of  coil  which  are  mostly  used, 
namely — loading   inductances,   loose  coup- 


wave  lengths  and  aerial  inductance  to  local- 
ized inductance  ratios. 

Considering  long  wave  lengths  (10,000 
meters  and  higher)  and  the  design  of  large 
loose  couplers,  we  are  safe  in  using  the 
expression : 

W.L.  =  59.6  \  I  x  C  ■ 
where : — 

L  =  inductance  of  loose  coupler  primary 
and  loading  coil   (if  used)  ;  the 


A  Modern  Long  Wave  Loose  Coupler  Provided  With  Dead-end  Switches.  To  Ensure  Accu- 
rate Inductance  Adjustments  in  Any  Case,  All  Switch  Connections  Should  be  Mounted  on 
Hard  Rubber  or  Bakelite.    A  Large  Loose  Coupler  Is  Usually  Superior  To  a  Small  One  and 

a  Loading  Coll. 


lers,  variometers  and  transmitting  oscilla- 
tion transformers. 

Before  we  delve  into  the  actual  design 
of  these  coils,  let  us  first  consider  the  first 
fundamental  facts  necessary  for  the  design. 
Since  the  inductance  is  employed  in  build- 
ing up  the  proper  oscillating  condition  of 
the  circuit  and  consequently  the  wave 
length,  we  can  express  this  relation  by  the 
following  formulae : 

We  have  first  the  formula  expressing  the 
wave  length,  IV. L.,  of  the  open  (antenna) 
oscillatory  circuit,  thru  the  primary,  Lo,  of 
a  loose  coupler,  loading  or  tuning  coil. 


inductance  of  the  antenna  being 
neglected,  owing  to  its  small  value 
compared  to  the  inductance  of  the 
loose  coupler  (or  loading  coil). 
C  =  capacity  of  antenna,  including 
lead-in. 


IV. L.  =  a  yj  I  x  c  i 


(1) 


where  :— 
A  =  a 


variable,  ranging  from  38.15  to 
59.6  for  short  wave  lengths.  (See 
curves  for  various  values  of  "A" 
in  article  above  cited,  in  Febru- 
ary, 1917,  issue.) 
L  =  total  inductance  in  centimeters  of 
aerial,  including  lead-in  and  loose 
coupler,  tuning  coil  or  loading 
coil. 

C  =  capacity  in  micro-farads  of  aerial, 
including  lead-in. 

Those  interested  in  this  subject  should 
refer  to  the  excellent  article  on  "The  De- 
sign of  Large  Radio  Receiving  Trans- 
formers," by  C.  S.  Ballantine,  in  the  Feb- 
ruary, 1917,  issue  of  this  journal,  page 
732.  The  variable  factor,  59.6,  appearing 
in  the  usual  wave  length  formulae  was  there 
discust  at  length,  with  a  graph  giving  the 
different  values  of  this  function  for  various 

*Parts  I  and  II  of  this  series  appeared  in  the 
March  and  April,  1917,  issues  of  The  Electrical 
Experimenter. 


One  Method  of  Winding  Radio  Inductances 
Involves  the  Use  of  a  Thread  Spun  on  Be- 
tween the  Turns. 


For  designing  short  wave  apparatus  we 
shall  call  L0,  the  value  of  the  loose  coupler 
(or  tuning  coil)  primary  inductance.  Then 
we  have  : 

X2 

Lo  =  L  ;  (2) 


here  :— 
U  = 

X  = 
L  = 
C  = 


3552  X  C 

inductance  of  load  (loose  coupler, 
tuner,  etc.),  in  centimeters. 

maximum  wave  length  to  be  tuned 
to. 

inductance  of  antenna  and  lead-in 
in  centimeters. 

capacity  of  antenna  and  lead-in  in 
micro-farads.  (See  tables  here- 
with for  these  values.) 


For  long  wave  apparatus,  let  Lo  represent 
the  loading  coil  inductance,  plus  the  in- 
ductance of  the  loose  coupler  primary  (or 
tuner,  if  used).  Then  we  have  the  formula: 


Lo  = 


3552  X  C 


(3) 


formula 


with  all  values  the  same  as  in 
No.  2. 

The  following  tables  will  be  found  use- 
ful in  applying  the  above  equations  to  the 
design  of  loose  couplers,  etc. 

TABLE  "A" 
Cap.  in  M.F.,  Including  Lead-in,  of  4  Wire  Inverted 
"L"  Aerials.    Wires  Spaced  3  Ft.  Apart 


Height 

i  Length  of  Flat-top  in 

Feet  , 

in  Feet 

60 

80 

100 

120 

40  

.00033 

.00042 

.00051 

.00060 

50  

.00035 

.00043 

.00050 

.00058 

60  

.00036 

.00044 

.00051 

.00059 

70  

.00037 

.00045 

.00052 

.00059 

80  

.00039 

.00046 

.00053 

.00060 

90  

.00040 

.00048 

.00055 

.00061 

100  

.00042 

.00049 

.00056 

.00062 

TABLE  "B" 

Inductance  in  Cms.,  Including  Lead-in,  of  4  Wire 
Inverted  "L"  Aerials 


Height 
imFeet 

40.  .. 

60.  .. 

80.  .. 
100. .. 


-Length  of  Flat-top  in  Feet- 


80 
41,100 

55,460 
69,320 
83,500 


100 
47,200 
62,090 
76,300 
90,750 


120 
53,310 
68,700 
83,300 
98,020 


It  is  possible  to  determine  approximately 
the  inductance  required  to  produce  a  de- 
sired wave  length  when  the  capacity  of  the 
total  oscillating  system  is  known.  When 
using  any  of  the  above  formulas,  it  should 
be  remembered  that  they  include  the  total 
value  of  the  unit.  Thus,  the  capacity  fac- 
tor includes  the  antenna,  and  condenser 
capacity,  each  of  which  must  be  determined 
separately  and  the  capacity  of  the  antenna 
must  be  obtained  by  actual  calculation, 
formula  for  deriving  this  quantity  having 
been  given  on  page  732  of  the  February, 
1917,  issue  of  this  journal,  as  well  as  a 
table  of  the  capacities  of  a  four  wire  an- 
tennae of  different  lengths  and  heights. 

The  first  step  in  the  design  of  an  in- 
ductive tuner  (having  determined  the  wave 
length)  is  the  actual  size  of  the  instru- 
ment, and  from  this  to  find  the  approxi- 
mate dimensions  of  the  winding  tubes  to 
be  used.  Having  these  on  hand,  and  know- 
ing the  maximum  inductance  of  the  pri- 
mary by  equations  (2  or  3),  we  can  imme- 
diately determine  the  number  of  turns  that 
the  primary  coil  will  require  to  obtain  the 
wave  length  sought,  by  solving  equation 
(3)  of  (Part  1,  March,  1917,  issue)  for  A7; 


Fig.  2  Shows  a  "Staggered"  Radio  Induc- 
tance and  Fig.  3  a  Sectional  View  of  the 
New  "Morecroft"  Multilayer  Radio  Winding, 
Designed  to  Have  Minimum  Distributed 
Capacity. 


September,  1917 


THE  ELECTRICAL  EXPERIMENTER 


321 


in  terms  of  units  we  obtain  the  following 
relation :   

1     IL  (3  S  +  d)  (4) 

N  =  -  J  

Sd\  3 

Where : — 
./V  =  total  required  number  of  turns. 
d  =  diameter  of  coil  in  inches. 
.S  =  length  of  coil  in  inches. 
L  =  inductance  required  in  centimeters. 

The  inductance  of  the  secondary  winding 
should  be  such  that  its  wave  length  should 
correspond  very  nearly  to  the  antenna  cir- 
cuit, and  that  of  the  primary.  If  this  con- 
dition is  to  be  obtained,  then  we  have  an 
ideal  condition  of  maximum  efficiency  and 
great  care  must  be  exercised  in  bringing 
about  this  ideal  condition.  The  value  of 
the  secondary  inductance  must  therefore  be 
in  the  neighborhood  of  the  primary  (unless 
it  is  to  be  shunted  by  a  variable  capacity), 
but  in  practise  it  is  made  somewhat  larger 
than  that  of  the  primary.  It  is  customary 
in  coupler  design  to  allow  one-half  inch 
difference  in  size  of  diameters  between  the 
primary  and  secondary  tubes  and  therefore 
the  diameter  of  the  secondary  can  readily 
be  determined.  The  number  of  turns  re- 
quired is  deduced  from  equation  (4). 

The  size  of  wire  to  be  used  on  the  sec- 
ondary coil  is  a  very  important  factor  in 
efficient  couplers,  and  the  only  factor  con- 
trolling the  diameter  of  the  wire  to  be 
used  is  whether  a  crystal  or  Audion  de- 
tector will  be  connected  in  the  secondary 
circuit.  Since  the  latter  type  is  a  potential 
operating  device  it  is  essential  that  the 
winding  should  consist  of  a  smaller  wire 
than  if  the  same  coil  is  to  be  connected 
to  a  crystal  detector.  The  reason  for  this 
is  that  the  energy  received  by  the  sec- 
ondary winding  is  so  infinitesimally  small 
that  any  superfluous  resistance  in  the  sec- 
ondary circuit  due  to  small  wire  winding 
destroys  the  intensity  of  the  rectified  cur- 
rent in  the  telephone  receiver ;  but  this 
condition  does  not  hold  true  for  a  poten- 
tial operating  detector  where  the  super- 
fluous resistance  is  overcome  by  applying 
a  greater  potential  in  the  circuit  by  the 
variation  of  the  "B"  battery  of  the  Audion 
circuit.  It  was  found  from  actual  experi- 
ments carried  out  by  the  authors  that  with 
an  Audion  detector,  the  secondary  winding 
should  be  made  with  a  gage  wire  ranging 


/vg.4 


Details  of  a  "Morecroft"  Radio  Inductance. 
In  Winding  the  Coil,  a  Layer  of  Card-board 
is  Placed  Between  the  Layers  to  Give  a 
Spacing  Between  All  Turns  as  Shown  Clear- 
ly in  Fig.  3. 

from  No.  28  to  32  B&S,  while  with  a  crys- 
tal detector  numbers  22  and  24  were  found 
to  give  best  results. 

After  the  primary  and  secondary  coil 
quantities  have  been  obtained,  the  speci- 
fied design  is  completed  and  the  next  step 
is  to  consider  the  general  mechanical  fea- 
tures of  the  tuning  devices  and  the  man- 
ner in  which  the  coils  are  held  in  place; 
the  latter  will  be  left  to  the  builder,  since 
each  one  has  his  own  idea  of  finishing  up 
an  instrument. 


It  is  advisable  at  first  in  winding  the 
coils,  that  no  shellac  or  any  kind  of  var- 
nish be  applied  to  the  wire  to  keep  it  in 
place,  as  the  capacity  dielectric  losses  be- 
tween adjacent  turns  are  considerably 
increased,  which  naturally  decreases  the 
efficiency  of  the  instrument.  An  ideal 
method  of  winding  the  wire  is  to  cut  a 
very  fine  thread  on  the  surface  of  the  tube 
in  a  lathe,  and  winding  the  wire  in  this 
thread,  if  a  coil  of  this  kind  was  going 
to  be  made,  hard  rubber  or  Bakelite  should 
be  used ;  the  latter  is  preferable  since  it 


always  employ  a  dead-end  szvitch  in  order 
to  reduce  losses  due  to  the  distributed 
capacity  inherent  in  the  coil.  Both  pri- 
mary and  secondary  windings  should  be 
equipt  with  one  of  these  switches,  and  a 
very  excellent  and  easily  constructed  type 
was  illustrated  and  described  on  page  33 
of  the  May,  1917,  issue  of  The  Electrical 
Experimenter. 

A  great  deal  of  deficiency  and  loss  of 
energy  accrues  to  the  use  of  wood,  hard 
rubber  and  fiber  for  switch  panels,  as  the 
former    usually   contains    water,    acid  or 


Prim,  coil  in  cabinet 


Loading  coil  of  eo  turns  28  wire 
8 taps  P/e '  ii'th/cA  Ins.d/om.  if 


sw.  izpts. 


slide  hole 


Contact  spring 


Construction  Details  of  4,000  Meter  Loose  Coupler  Having  Dead-end  Switches  in  Primary  and 
Secondary  Circuits.    The  Secondary  Terminals  Are  Attached  to  the  Slider  Rods,  Against 
Which  Two  Brushes  Bear,  These  Brushes  Being  Placed  Inside  the  Secondary  Form. 


does  not  warp  during  changes  of  weather 
conditions.  The  method  of  winding  a  wire 
on  a  threaded  tube  is  also  advantageous 
in  reducing  the  distributed  capacity  of  the 
winding. 

Still  another  method  of  winding  the  wire 
on  a  coil  upon  which  a  thread  can  not  be 
machined,  is  to  wind  a  fine  silk  thread 
between  adjacent  turns.  Fig.  1  shows  how 
it  is  done.  This  method  of  winding  has 
been  used  considerably  in  building  high 
grade  inductance  coils  and  has  proved  of 
sufficient  merit  to  warrant  its  use  with 
inductive  coupler  windings. 

The  question  of  tap  connections  and 
switches  is  a  very  important  one  in  de- 
signing inductive  transformers,  and  the 
following  points  should  be  kept  in  mind 
by  the  designer :  i.  e.,  that  all  connections 
from  winding  leads  should  be  as  short  as 
possible;  all  connections  are  to  be  invari- 
ably soldered  and  if  possible  they  should 
consist  of  stranded  cable  in  order  to  re- 
duce lead  resistance.  These  terminal  leads 
should  be  soldered  to  copper  lugs  which 
are  connected  to  the  switch  point.  The 
latter  must  be  free  from  any  lacquered 
plate  coating  as  this  increases  the  high 
frequency  resistance  due  to  an  increase  of 
metal  surface.  It  has  been  found,  however, 
that  if  the  metal  is  silver-plated  and  its 
surface  kept  white  (not  lacquered),  that 
the  increase  of  surface  resistance  to  high 
frequency  currents  is  negligible.  Care 
should  be  taken  to  keep  the  buttons  and 
switch  blade  contact  as  clean  as  possible, 
in  order  to  minimize  the  contact  resistance. 
This  also  applies  to  the  elimination  of  the 
use  of  lacquer  or  any  other  form  of  polish 
on  switch  contact  surfaces. 

It  is  advisable  in  building  a  coupler  to 


other  mineral  substances,  which  cause  a 
partially  short-circuit  on  the  taps ;  conse- 
quently not  permitting  the  total  energy  to 
traverse  the  winding,  which  naturally  does 
not  permit  the  total  flux  induction  to  take 
place  between  the  windings. 

The  fiber  and  hard  rubber  panels  are 
not  satisfactory  for  the  simple  reason  that 
their  surface  deteriorates  in  time,  and  with 
the  latter  material,  a  film  of  sulfur  is 
formed  which  collects  dust,  into  which 
metallic  particles  lodge.  These  produce  a 
short-circuit  between  contacts.  Fiber,  too, 
is  rather  hygroscopic.  The  best  material 
for  the  construction  of  switch  panels  is 
Bakelite,  which  makes  an  ideal  insulator 
for  radio  work.  It  is  used  on  all  receiving 
sets  now  built  by  the  large  commercial 
companies. 

For  the  benefit  of  those  who  desire  to 
build  an  excellent  4,000  meter  loose  coupler, 
we  give  herewith  a  complete  working  draw- 
ing of  one. 

There  is  still  another  type  of  inductance 
coil  which  has  recently  proven  very  satis- 
factory for  tuning  long  waves,  and  this  is 
the  multilayer  coil.  During  the  last  few 
years  considerable  criticism  was  made 
against  the  use  of  these  coils,  due  to  the 
untoward  distributed  capacity  effect  pro- 
duced by  adjacent  layers.  However,  these 
criticisms  lost  themselves  among  certain 
radio  engineers  who  have  been  working  on 
this  problem  and  notably  the  Telefunken 
experts,  who  have  evolved  the  so-called 
staggered  winding  multilayer  coils,  which 
consists  of  tapering  layers  of  wire  on  top 
of  each  other  in  the  manner  shown  in 
Fig.  2.  The  first  layer  A  was  wound  in 
the  usual  way ;  the  second  layer  B  was 
(Continued  on  page  322) 


322 


THE  ELECTRICAL  EXPERIMENTER 


September,  1917 


"RELAY  KEY"  MADE  FROM  TELE- 
GRAPH SOUNDER. 

I  give  below  description  of  an  easily 
made  relay  key. 

A  good  many  amateurs  are  using  the 
small  (legless)  type  of  telegraph  key  and 
are  bothered  with  the  points  burning  away 
— at  least  that  was  my  trouble  until  I 
thought  of  this  way  of  preventing  it. 

I  don't  think  that  this  key  has  ever  ap- 
peared in  your  magazine  as  I  have  been  a 
reader  of  The  Electrical  Experimenter 
for  the  past  two  years  and  have  never  run 
across  it  among  the  pages  of  your  very 
useful  magazine. 

The  relay  key,  which  is  nothing  more 
than  an  old  telegraph  sounder,  is  easily 
made  and  I  think  that  most  amateurs  have 
the  necessary  material  lying  in  their  junk 
heaps. 

Cut  a  piece  of  fiber  2j4"xj£"xI4".  Drill 
two  y%"  holes  thru  this  and  the  bar  of 
the  sounder  and  fasten  these  together  with 
bolts.  Then  drill  a  hole  thru  the  outer 
end  of  the  fibre  bar  and  fasten  on  a  piece 
of  copper,  to  which  an  old  binding  post  has 
been  riveted.    Another  binding  post  serves 


fibre  Bar 
Copp?r 
i  tea,  iSfr/0 


 r 


-f 


is  due  to  Prof.  J.  H.  Morecroft  of  Colum- 
bia University,  who  has  done  considerable 
research  work  in  radio. 

It  was  pointed  out  in  an  article  on  "Dis- 
tributed Capacity  and  Its  Effect"  in  the 
May,  1917,  issue,  that  on  the  long  single- 
layer  coil  the  distributed  capacity  increased 
with  an  increase  of  coil  length,  and  that 
the  potential  effect  is  greatest  at  the  end 
of  the  coil.  It  naturally  follows  that  with 
extremely  long  coils  the  voltage  is  ex- 
tremely "high  at  their  ends,  as  compared 
with  any  of  the  apparatus  used  in  the 
tuning  circuit.  It  has  usually  been  con- 
sidered that  multilayer  coils  had  consider- 
ably greater  distributed  capacity  than  those 
of  the  single  layer  type,  due  to  the  prox- 
imity of  the  layers  making  up  the  coil,  but 
it  has  recently  been  found  that  by  properly 
constructing  such  coils,  the  inherent  capa- 
city is  minimized.  This  fact  was  proved 
by  constructing  two  multilayer  coils  where 
the  layers  of  each  winding  were  separated 
by  a  layer  of  air  as  indicated  in  Fig.  3. 
One  of  these  coils  has  twenty  layers,  the 
other  ten  layers,  yet  the  distributed  capacity 
was  found  to  be  very  low,  or  of  the  order 
of  25  centimeters  and  an 
inductance  value  of  about 
70  milli-henries. 

The  winding  is  made 
over  a  cagelike  insulating 
reel,  by  eight  wood  pins 
past  thru  two  end  pieces. 
After  one  layer  is  wound 
a  strip  of  cardboard  is 
placed  across  the  winding 
right  over  each  wooden 
peg.  The  next  layer  is 
then  wound  on  and  the 
cardboard  strips  give  an 
air  space  between  the  two 
layers.  Each  successive 
layer  is  wound  in  a  similar 
manner,  giving  an  air  space 
between  layers. 

The  inductance  of  multi- 
layer coils  of  the  More- 
croft type  is  obtained  from 
equation  No.  10,  Part  1  of 
this  series.  The  notation 
of  symbols  is  the  same. 
The  cross-sectional  dia- 
gram, Fig.  2,  of  the  first 
series  shows  a  multilayer 
coil  without  an  air  space 
between  layers,  but  the  re- 
lation of  the  units  holds 


1 

'llliiw/'*.  "Ol  I 

J 

Substantial  Design  of  Heavy  Current  Relay  Key  Which  Can   true  for  the  air  space  coils, 
Be   Made  from   a    Discarded   Telegraph    Sounder.  since  the  dimension  of  the 

air  space  must  be  consid- 
ered in  the  actual  calculation. 

In  determining  the  capacity  of  multilayer 
coils  the  following  equation  has  been  found 
quite  accurate: 

be 

C  =  —  I  —  +  0.8  | 
420  Lex 

Where : — 

C  =  capacity  in  milli-microf arads. 
a  =  means  radius  of  coil  (inches). 
b  =  axial  length  of  coil  (inches). 
e  —  2.718. 

c  =  winding  depth  of  coil  (inches). 
x  —  insulation  thickness  between  layers 
in  mils. 


as  the  bottom  contact,  it  having  been  fast- 
ened to  the  base  of  the  sounder,  as  shown 
in  the  drawing,  when  the  key  is  ready  to 
hook-up.  Two  dry  cells  will  be  sufficient 
to  operate  this  key  as  it  works  similar  to 
the  telegraph  sounder  and  the  battery  will 
not  burn  the  points  off  the  small  key  as 
will  the  A.C. 

Contributed  by       DON  I.  BAILEY. 


[r, +  °'8] 


(5) 


CALCULATION  AND  MEASURE- 
MENT OF  INDUCTANCE. 

(Continued  from  page  321) 

started  from  the  center  of  the  first  two 
turns  as  shown;  the  third  between  the  first 
two  of  the  second  layer  and  so  on  until 
the  last  winding  which  consisted  of  a 
single  turn. 

Great  precaution  must  be  exercised  in 
making  the  turn  for  the  approaching  next 
layer.  This  is  done  by  making  a  sharp 
bend  in  the  wire.  This  type  of  coil  has 
been  used  with  success  for  a  number  of 
years  by  the  Telefunken  concern,  and  they 
are  still  being  used.  They  are  excellent 
for  building  inductances  for  long  wave 
lengths  in  a  small  space. 

Something  new  in  multilayer  inductances 
is  shown  in  Figs.  3  and  4.    This  design 


The  first  part  of  the  equation  represents 
the  capacity  due  to  the  dielectric  flux  be- 
tween layers,  and  this  varies  with  the  dif- 
ferent parts  of  the  coil  as  the  variation  of 
voltage  is  different  at  the  various  lengths 
of  the  winding.  It  also  takes  care  of  the 
dielectric  losses  due  to  the  wire,  and  for 
air,  which  is  used  in  the  Morecroft  coils, 
it  is  unity.  Various  other  losses  are  en- 
countered in  these  types  of  coil  such  as 
eddy  current,  hysteresis  and  skin  effect,  all 
of  which  losses  are  still  under  investiga- 
tion. 

The  general  construction  and  dimensions 


of  the  Morecroft  multilayer  coil  is  shown 
in  Fig.  4.  The  ends  are  made  from  well- 
seasoned  wood  and  the  J4"  dowel  pegs 
are  glued  into  the  holes  made  in  the  side 
pieces  as  indicated.  The  winding  consists 
of  ten  layers  of  No.  30  silk  covered  wire. 
Each  layer  consists  of  75  turns. 

The  great  advantages  of  these  coils  are 
that  long  wave  lengths  can  be  tuned  with 
a  small  size  coil,  and  the  capacity  effect 
of  the  operator's  body  upon  the  coils  is 
minimized,  which  eliminates  the  detuning 
effect  on  the  oscillating  Audion  circuit  when 
the  operator  stands  near  his  apparatus. 
This  effect  is  very  noticeable  when  the  long 
inductance  coils  are  employed. 

This  completes  this  series,  and  it  is  the 
aim  of  the  authors  to  have  the  information 
given  herein  accurate  and  concise  so 
that  it  may  prove  of  value  to  both  the  elec- 
trical and  radio  experimenter  who  reads 
these  columns.  The  student  who  is  en- 
deavoring to  master  the  various  problems 
of  the  calculation,  measurement  and  appli- 
cation of  inductance  coils  in  radio  circuits 
will  do  well  to  procure  copies  of  the  March 
and  April,  1917,  numbers,  the  three  articles 
forming  a  complete  series.  This  is  a  sub- 
ject which  no  prospective  radio  expert, 
whether  operator  or  engineer,  can  afford 
to  neglect. 

AUDION    EXPERT    IS  AWARDED 
RADIO  ENGINEER'S  HONOR 
MEDAL. 

The  first  award  of  the  medal  of  honor  of 
the  Institute  of  Radio  Engineers  which  was 
described  and  illustrated  in  our  July  issue 
of  The  Electrical  Experimenter  has  been 
presented  to  Mr.  Edwin  H.  Armstrong, 
E.  E.,  of  the  Radio  Research  Department, 
Columbia  University,  New  York  City,  in 
recognition  of  the  valuable  contribution  to 
the  art  represented  in  his  work  in  con- 
nection with  receiving  apparatus,  and  par- 
ticularly to  the  efficiency  of  the  well-known 
Armstrong  Circuit. 

It  will  come  as  a  surprise  to  many  of 
our  wireless  readers  no  doubt  to  learn 
that  Mr.  Armstrong's  regenerative  Audion 
circuit  was  developed  and  perfected  in 
his  amateur  experimental  days.  This  sim- 
ply goes  to  prove  that  much  is  to  be  gained 
by  experiment  in  the  radio  field,  and  this 
should  prove  a  decided  incentive  to  every 
radio  amateur  worth  his  salt.  Certain  it 
is,  that  little  may  be  gained  that  is  really 
worth  while  by  simply  owning  a  radio 
station,  if  one  intends  to  simply  sit  at  the 
apparatus  and  punch  the  key.  In  this,  as 
in  every  other  field  of  scientific  endeavor, 
and  wireless  certainly  is  scientific  if  any- 
thing, it  has  always  developed  in  practically 
every  case  on  record  that  wherever  a  revo- 
lutionizing, original  idea  or  invention  has 
been  evolved,  that  back  of  it  all  there  was 
invariably  a  vast  amount  of  hard  work 
which  required  much  study  and  experi- 
mental research.  The  present  situation, 
when  all  experimental  wireless  stations 
have  been  closed  by  the  Government,  due 
to  the  war,  should  prove  nothing  less  than 
a  spur  to  urge  the  real  radio  amateur  on 
to  a  higher  goal.  "After  the  War"  days 
are  surely  coming,  and  with  them  will 
come  a  wonderful  opportunity  for  radio  ex- 
perts,- not  to  mention  the  present  great 
opportunities  in  the  Army  and  Navy  sig- 
nal divisions,  besides  many  lucrative  posi- 
tions available  with  industrial  concerns  at 
the  present  time  for  first-class  radio  ex- 
perts. 

Due  to  the  advent  of  the  war,  we  are 
particularly  desirous  of  obtaining  manu- 
scripts describing  original  and  practical 
"Electrical  Experiments."  We  shall 
continue  to  publish  Radio  articles,  but 
what  we  need  is  snappy  "Electrical" 
articles.  Be  on  guard  for  the  enemy — 
Repetition! 


September,  1917 


THE   ELECTRICAL  EXPERIMENTER 


:T3CZ)C=3l" 


How  I  Built  A  2X  H.P.  Flivverette 

By  CLEAGE  FEILD 


"A.  TOT 


OTHING  succeeds  like  success," 
would  seem  to  be  the  beacon- 
ight  of  one  Master  Cleage  Feild, 
age  fifteen  years,  who  has  pa- 
tiently designed  and  built  the 
racy  looking  motor  car  in  miniature  here 
shown.  Like  many  other  motor  car  makers 
of  the  day,  Master  Feild  has  assembled 
his  parts  around  an  engine  that  runs,  pre- 
ferring not  to  take  chances  on  casting 
and  machining  the  engine  parts.  The  in- 
ventor deserves  considerable  credit  for  his 
ingenuity  in  building  a  little  pleasure  auto- 
mobile that  really  gets  there.  It  covers 
the  ground  at  a  speed  of  20  miles  per 
hour  easily  and  35  miles  on  a  gallon  of 
gas  is  regular  work  with  Cleage.  -Fellow- 
bugs — electrical,  mechanical  and  radio — 
Master  Feild.  Master  Feild,  etc.  The  in- 
troduction having  been  effected,  let  us  read 
what  this  young  mechanic  and  inventor  has 
to  say  regarding  the  details  of  his  2y2  H.P. 
flivver-ette. — Editor. 

Construction  Details 

Frame — The  frame  is  of  red  oak,  one 
and    three-fourth    inches    square.     It  is 


Wheels — These  are  No.  3,  Auto  wheel, 
coaster,  size  10  inches  high  and  use  }4- 
inch  axle.  They  are  roller  bearing  and 
are  held  on  by  cotter  pins.  The  wheel 
base  is  58  inches.  The  front  axle  is  riveted 
to  the  block,  while  the  rear  one  revolves 
in  four  iron  boxes. 

Brake — I  have  only  a  foot  brake.  This 
pushes  on  the  rear  left  wheel  and  the 
pedal  for  it  is  on  the  same  side  of  frame. 

Seat- — I  have  three  seats  which  may  be 
changed  to  suit  the  occasion,  a  wooden 
one,  which  is  my  country  and  county  seat, 
another  one  which  came  off  of  a  girls' 
tricycle,  which  is  my  town  seat.  And  a 
small  leather  auto  seat  which  is  my  "Sun- 
day best" ! 


seventy-four  inches  long,  fourteen  inches 
wide  and  thirteen  inches  above  the  ground. 
It  is  bolted  at  the  corners  and  braced  by 
pine  and  oak  strips. 

Hood — The  hood  is  of  oak  with  poplar 
slats  on  it,  4  inch  slope,  27  inches  long,  14 
inches  wide,  15  inches  high  in  front  and 
19  inches  back.  A  screened  hole  in  the 
front  admits  air.  It  has  two  hooks  on 
each  side  to  secure  it  to  the  frame. 

Dash  Board— The  dash  is  separate  from 
the  hood  and  is  nailed  to  the  bed.  It  is 
made  of  oak  and  has  the  same  dimensions 
as  the  back  of  the  hood. 

Steering  Gear — This  runs  thru  the  dash 
in  an  iron  box;  the  rod  is  a  piece  of 
broom  handle  and  the  wheel  came  from 
a  book  press.  The  horn  (hand  Klaxon) 
is  clamped  to  this  rod.  Ropes  wrapt 
around  the  part  of  the  rod  under  the 
hood,  in  opposite  directions,  run  thru  pul- 
leys on  the  left  of  frame  to  the  swivelled 
front  axle  block,  as   shown  in  drawing. 


Boys,  Wouldn't  You 
Like  to  Ride  Around 
Town  in  Your  Own 
Little  Car?  Read  the 
Story  of  How  a  15- 
Year-Old  Genius  Built 
HisOwn  "Racer"  From 
Odd  Parts. 


Engine—The  engine  is  a  2y2  horse  power, 
Shaw  bicycle  attachment,  air-cooled  type. 
It  is  fastened  to  the  frame  by  iron  strips 
and  bolts.  I  use  a  Cico  spark  plug  and  a 
contact  timer  equipt  with  a  spring  to  keep 
it  shut  off.  In  the  cylinder  head  is  a  prim- 
ing cup  which  can  be  used  as  a  compres- 
sion release  when  starting. 

Carburetor — The  carburetor  is  a  small 
one-half  Acme  Essex,  of  the  float  valve 
type. 

Tank — The  gas  tank  is  made  of  a  copper 
tank  cut  in  two;  it  has  a  copper  tube  run- 
ning from  it  to  the  carburetor.  The  tank 
is  on  the  back  of  the  dash  board  and  has 
a  capacity  of  one-half  gallon.  It  has  a 
screw  cap  on  top  of  it. 

Piston — This  has  three  rings  and  is  con- 
nected directly  to  the  two  fly  wheels,  which 
are  enclosed  in  the  crank  case. 

Oil  System — The  oil  is  poured  into  the 
oil  case  thru  a  plug. 


Ignition — The  ignition  consists  of  the 
spark  plug,  four  dry  batteries  (which  are 
located  in  the  box  behind  the  seat),  a 
vibrator  coil  (which  will  give  about  54- 
inch  spark),  a  switch,  the  ground  connec- 
tor, the  timer  and  wires  connecting  them 
all  together  properly. 

Controls — The  spark  is  the  main  con- 
troller of  the  speed  of  the  engine.  A 
wire  runs  from  the  timer  to  a  small  lever 
which  works  into  a  notched  slot.  This 
lever  may  be  seen  on  left  of  frame.  The 
gas  feed  is  regulated  by  a  string  which 
opens  and  shuts  the  vaporizing  chamber 
door.  Since  my  drive  was  changed  I  have 
no  need  for  an  idler. 

Drive — This  is  the  last,  but  very  import- 
ant subject.  The  engine  runs  in  opposite 
direction  to  the  wheels,  but  the  gears,  as 
you  can  see  in  the  drawing,  being  only 
two,  reverse  the  direction  of  pull,  causing 
.the  wheels  to  go  forward.  My  gears  and 
the  boxes  connected  with  them  and  the 
rear  axle  I  got  off  of  an  old  "Irish  Mail 
Flyer."  The  small  countershaft  was  once 
the  axle  of  a  wheel-barrow  and  two  of 
the  boxes  on  the   rear  axle  came  from 


the  same  outfit.  The  left  rear  wheel  is 
equipt  with  bearings  like  the  front  two, 
but  the  right  and  drive  wheel  is  different. 
I  found  the  end  of  the  axle  cut  almost 
square,  or  I  would  have  done  it  myself. 
A  piece  of  a  flat  iron  strip  with  a  square 
hole  in  it  was  fitted  over  the  axle  and 
bent  thru  the  spokes.  This  clamps  axle 
and  wheel  firmly  together.  The  automatic 
idler  I  spoke  of  is  very  good.  The  pull 
of  the  belt,  which  is  at  the  bottom  of  the 
rear  pulley  wheel,  tends  to  raise  the  small 
gear,  boxes,  shaft  and  itself  upward.  This 
movement  lengthens  the  distance  between 
pulleys  and  tightens  the  belt.  The  smaller 
gear,  as  you  can  see,  would  naturally  climb 
up  the  larger  one  and  do  the  same  as 
above. 

A  few  facts — My  car  will  make  about 
20  miles  per  hour.  The  wheels  altho  a 
little  too  small,  possibly,  are  very  good. 


324 


THE  ELECTRICAL  EXPERIMENTER 


September,  1917 


Seven  Years  of  Wireless 

By  HOWARD  S.  PYLE 


fn<xine 


Head 
Lid  fit 


J=i  .I-.  Brake 


Gear  fix- 
ed on 
Shaft 


WELL  I  remember  my  first  days  in  the 
mysteries  of  wireless,  seven  years  ago. 
It  all  started  with  the  problem  of 
ringing  a  bell  from  a  220-volt  source  of 
supply.  The  results 
exceeded  my  great- 
est expectations.  But 
in  them  was  kindled 
the  fire  of  experi- 
mentation. The  usual 
collection  of  junk 
accumulated  in  dif- 
ferent parts  of  the 
house  until  finally 
I  was  forced  to  seek 
larger  quarters  in 
the  attic.  There  be- 
gan the  construction 
of  an  indoor  aerial 
of  bell  wire;  four 
strands,  thirty  feet 
long  and  about  the 
same  height,  tacked 
to  the  rafters ;  a 
"coal"  detector  and 
a  receiver  borrowed 
from  the  family 
'phone.  Three 
months  were  spent 
in  vain  endeavor  to 
pick  up  the  Navy 
Yard  station,  15 
miles  away.  I  recol- 
lect trying  all  man- 
ner of  mineral  mat- 
ter in  the  detector 
— from  gold  nug- 
gets to  tinfoil  wads, 
finally  abandoning 
the  detector  to  look 
for  other  trouble. 

I  finally  purchased 
a  75  ohm  watch 
case  receiver  for  40 
cents  and  began 
anew.  Still  no  re- 
sults, so  the  aerial 
came  down  post 
haste  and  was 
replaced  by  a  single 
wire  100  feet  long 
and  40  feet  high, 
running  parallel  to  a 
220-volt  A.  C.  cir- 
cuit, but  four  feet 
below,  for  its  full 
length.  A  trip  to 
New  York  (my  sta- 
tion being  in  Pater- 
son,  N.  J.),  resulted 
in  the  purchase  of  a 
highly  nickeled  but 
extremely  small 
tuning  coil  of  the 
double  slide  variety, 
a  piece  of  silicon 

crystal  and  a  potentiometer.  After  strug- 
gling along  with  meagre  instructions  from 
the  first  wireless  catalog  published.  I  finally 
jimmied  the  collection  of  apparatus  (?) 
into  a  workable  hook-up,  according  to  a 
printed  diagram  and  with  a  thrill  of  ex- 
pectation, glued  the  receiver  to  my  ear. 
The  only  response  was  a  humming  so  loud 
that  my  ear  sang  for  some  minutes  after- 
ward. After  three  days  of  this  I  asked 
information  of  a  more  advanced  radio 
friend  and  with  his  help  and  advice,  placed 

It  will  climb  any  ordinary  hill.  I've  been 
working  to  get  this  perfected  for  nearly 
a  year  and  my  new  drive  system  so  far 
has  been  a  great  success.  If  any  one  desires 
any  more  details  I  shall  be  pleased  to  write 
them.  Address  me  in  care  of  the  Editor, 
inclosing   stamped  envelope. 


my  one  wire  aerial  at  right  angles  to  the 
A.  C.  power  circuit.  Upon  trying  the  set 
we  found  the  hum  almost  entirely  elimi- 
nated but  "no  sigs."    Where  then  w*as  the 


DET/f/L  OF 
DG/V/rVG  W/iEi-L 
"X 


Square/Vole 
to /it  in  end 
of  Shaft 


Pulley's 
Tastened 
to  frame 


(Abteactio, . 

w fieri  tu  miner  rod) 


WIBtm  SYSTEM 


BrakeTreadlet 


Bearings* 

Pinion 
^ fixe  dor? 
Lounter 
Sfia/t 


^Belt  tofngine 


Belt  Pulley 

DriVinyWfieel"X" 
Pfffg   )  Position  of  optional 


p 

Pivoi 

teenn^"  Popes 


>~ak e  Shoe 

DP/V//VG  GE/?R 


Leother;  Canvas, 
Pope  or  Chain  Self 


Why  Wish  for  a  Flivver-ette,  "Bugs"?    Here's  How  to  Make  One  From  the  Simplest  Materials 
Possible.    Four  Wheels,  a  Few  Sticks  of  Wood,  a  Broom-stick,  a  Battery  and  Spark  Coil,  and 
Lastly — a  Discarded  Motorcycle  Engine  That  Still  Peeps,  and  You're  In  for  the  Tim"  of  Your 
Life,  Even  to  Stealing  Your  Rival's  Best  Girl. 


trouble?  After  a  thoro  investigation  and 
testing  of  each  individual  piece,  we  found 
the  wire  on  the  tuner  to  be  a  continuous 
short-circuit  under  the  sliders.  An  expert 
friend  constructed  and  presented  me  with  a 
small  but  well-built  loose-coupler  at  this 
time,  which  probably  was  the  only  thing 
that  prevented  me  from  turning  to  a  more 
gratifying  art.  At  last  after  seven  months 
of  experimentation  and  disappointment,  the 
coupler  was  hooked  in  and  we  received 
good  signals  from  two  stations,  one  about 
twelve,  the  other  fifteen  miles  away,  both 
five  kilowatt  installations. 

This  fired  me  to  greater  efforts  and  the 
remaining  three  years  of  my  residence  on 
the  east  coast  were  spent  in  constant  ex- 
perimentation and  endeavor  to  improve  on 
the  original  installation,  which  finally  con- 
sisted of  two  loose-coupled  receivers  and 


a  l/z  K.  W.  transmitter,  a  complete  descrip- 
tion of  the  whole  installation  appearing 
around  about  the  latter  part  of  1911  in  the 
Modern  Electrics  magazine.  A  combination 
of  circumstances  resulted  in  my  being  com- 
pelled to  drop  Radio  work  for  about  six 
months,  but  at  the  first  opportunity  I 
erected  a  two-wire  aerial  90  feet  long  and 
40  feet  high,  and 
started  in  again  on 
the  Pacific  Coast.  I 
found  conditions 
here  much  better,  be- 
ing remarkably  free 
from  the  trouble- 
some static  of  the 
Atlantic  seaboard. 
However,  the  sta- 
tions out  here  were 
few  and  even  less 
Amateurs,  as  this 
was  about  the  time 
that  the  Radio  law 
went  into  effect.  I 
made  immediate  ap- 
plication and  re- 
ceived one  of  the 
first  second  -  grade 
amateur  licenses  is- 
sued. After  about  a 
year's  work,  during 
which  time  nothing 
particularly  note- 
worthy occurred,  we 
again  changed  our 
residence,  still  re- 
maining in  Seattle, 
however.  Right 
after  these  things 
began  to  happen,  the 
Marconi  people  in- 
stalled a  5  K.  W. 
station  in  the  tallest 
building  west  of  . 
Chicago,  which 
brought  them  just 
three  miles  from 
me — a  high  -  power 
station  was  es- 
tablisht  at  Astoria, 
Ore.,  300  miles  S.W. 
by  the  same  com- 
pany. The  Y.  M. 
C.  A.  undertook  the 
instruction  of  oper- 
ators for  commer- 
cial service  and  a 
local  concern  began 
the  manufacture  and 
installation  of  radio 
equipment  on  vessels 
of  this  coast.  I  se- 
cured employment 
with  this  concern 
and  worked  on 
the  installation  of 
the  Alaska  S.  S. 
Co.,  involving  about 
15  complete  1  K. 
W.  equipments.  I 
course  at  the  Y.  M. 
settled  down  to  real 
five  evenings  a 
I  was  not  equipt 


c///pssfs 


FPO/VT 


also  took  up  a 
C.  A.  school  and 
earnest  work,  averaging 
week  at  my  instruments, 
for  sending  for  about  two  years,  but  spent 
a  great  deal  of  time  in  perfecting  my  re- 
ceiving equipment.  My  "log  book,"  which 
I  have  always  kept  up-to-date,  shows  many 
trials  and  disappointments  which  have  been 
conquered,  and  makes  interesting  reading 
for  me  now,  I  can  tell  you. 

A  little  later,  I  met  thru  our  "ads"  in  a 
radio  publication  an  old  United  Wireless 
operator  who  had  a  1  K.  W.  United  trans- 
mitting installation  for  sale,  and  this  I 
purchased  and  brought  up-to-date.  I  had 
hardly  installed  it  when  we  again  moved  to 
our  present  location,  and  where  I  have 
practically  completed  a  first-class  1  K.  W. 
station,  which  awaits  the  end  of  war. 


September,  1917 


THE  ELECTRICAL  EXPERIMENTER 


325 


Selenium  Cell  Design  and  Construction 

By  THOS.  W.  BENSON 


THAT  selenium  or  one  of  its  closely 
related  elements  possessing  similar 
properties  will  find  many  uses  in 
the  near  future  is  a  logical  and 
foregone  conclusion.  In  the  past 
its  sporadic  applications  have  been  many, 
but  its  present  status  remains  more  or  less 
in  an  experimental  stage.  Among  other  ap- 
plications, we  find  that  Minchin  used  it 
in  his  astronomical  work,  Prof.  Barnard 
of  Lick  Observatory  employed  selenium 
cells  in  a  device  to  automatically  detect 
comets,  Siemens  for  photometric  measure- 
ments, Ruhmer,  Bell  and  Taintor  and  others 
for  wireless  telephony  and  experimenters 
without  number  have  employed  selenium 
in  one  way  or  another  in  an  effort  to  trans- 
mit pictures  over  a  wire.  Among  these 
might    be   mentioned    Senlecq,  Larroque, 


Terminals 


Deadends 


-w/i~es 

Selenium    fig.  5 

rig.  2 


Rods 


I  y^iAi 

fig 


fig.  5 


rig4 


Copperplate? 


Term.l 


Transparent  sneet  J  ,.•  r 
of.<jo/</  fo//  


Various  Types  of  Selenium  Cells:  Fig.  1, 
Cross-Section  of  a  Bidwell  Cell;  2,  Modified 
Bidwell  Type;  3,  Second  Type  of  Modified 
Bidwell  Cell;  4,  Bell  and  Taintor  Cell;  5,  the 
Mercadier  Cell  and  Finally  the  Fritts  Form 
of  Selenium  Cell,  Fig.  6,  Which  Is  the  Most 
Sensitive  Ever  Discovered,  the  Light  Shining 
Thru  the  Thin  Gold  Foil. 


Korn,  Dussaud,  Liesengang  and  DePaloa. 

Many  experts  have  bent  their  efforts  to 
the  perfection  of  the  selenium  cell  proper, 
rather  than  the  application  of  the  same, 
and  it  is  their  work  with  which  we  will 
deal.  Among  these  workers,  the  names  of 
Giltay,  Draper,  Hittorf,  Adams  and  Day, 
Ayrton  and  Perry,  Mercadier,  Bidwell, 
Ruhmer,  Hammer,  Fritts  and  Gripenberg 
are  the  more  prominent.  Despite  their  ef- 
forts the  selenium  cell  of  today  is  far 
from  being  a  reliable  piece  of  apparatus. 
This  may  be  due  to  a  certain  extent  to 
the  fact  that  the  material  is  but  little 
understood. 

The  physical  changes  that  take  place  when 
the  substance  is  heated  are  too  well  known 
to  require  extensive  mention,  but  the  ac- 
tion of  the  light  on  the  metal  is  still  the 
subject  of  much  conjecture.  And  herein 
lies  the  stumbling  block. 

We  can,  however,  draw  certain  conclu- 
sions that  will  assist  us  greatly  in  design- 
ing selenium  cells  that  are  nearly  alike 
in  their  various  characteristics.    For  one 


thing  the  light  can  only  affect  the  surface 
of  the  cell,  but  it  is  reasonable  to  sup- 
pose, ^however,  that  the  ultra-violet  rays 
can  penetrate  the  material  to  a  certain  ex- 
tent, since  it  is  more  effective  in  alter- 
ing the  resistance  of  the  cell.  The  longer 
light  waves  of  the  visible  spectrum  act  on 
the  surface  only,  since  the  metallic  form 
of  selenium  is  opaque. 

Then  again,  just  what  is  the  action  of 
the  light  when  it  strikes  the  cell?  Sev- 
eral theories  of  the  physical  action  oc- 
curring have  been  put  forward,  one  being 
that  since  light  is  a  form  of  electro-mag- 
netic ether  vibration  it  may  act  to  cohere 
the  particles  of  the  metal  in  a  manner  re- 
sembling the  action  of  the  well-known 
coherer  and  thus  serve  to  reduce  the  re- 
sistance of  the  material. 

This  theory  was  rendered  highly  im- 
probable by  the  research  work  of  Adams 
and  Day,  who  in  1877  publisht  the  results 
of  a  series  of  experiments.  They  claim 
that  the  conduction  thru  a  selenium  cell 
differs  from  metallic  conduction,  partaking 
of  that  occurring  in  an  electrolyte  when 
the  current  passing  decomposes  the  solu- 
tion. This  would  seem  to  support  the  the- 
ory that  the  light  falling  on  the  selenium 
causes  the  same  to  throw  off  electrons  and 
in  this  manner  form  a  low  resistant  con- 
ductor. The  latter  phenomena  is  well  known 
and  has  been  the  subject  of  much  research 
work,  particularly  by  Fleming. 

Even  so,  we  are  now  in  a  position  to 
design  cells  with  a  maximum  sensitive- 
ness. As  in  the  case  of  other  conductors 
the  resistance  of  selenium  increases  di- 
rectly with  the  length  and  decreases  as 
the  area  is  increased.  Therefore  a  cell 
made  in  the  usual  form,  that  is  with  wires 
wound  on  a  support  as  in  the  Bidwell  type, 
will  have  a  low  resistance  due  to  the  com- 
paratively large  area  of  selenium  lying  be- 
tween the  wires. 

Referring  to  Fig.  1,  a  cross-section  is 
shown  of  this  type  of  cell  with  the  selenium 
applied.  The  insulating  support  of  slate, 
mica  or  porcelain  is  shown  at  A,  the  spir- 
ally wound  parallel  conductors  at  B,  B,  etc., 
while  the  selenium  is  shown  at  C.  A  cell 
so  constructed  is  not  sensitive,  for  the  fol- 
lowing reason :  The  light  only  affecting 
the  surface  of  the  selenium  may  reduce 
the  resistance  of  the  surface  to  a  great 
extent,  but  the  total  resistance  of  the  selen- 
ium present  is  only  slightly  affected,  as 
will  be  clear  by  applying  the  law  cover- 
ing resistances  connected  in  parallel. 

The  above  condition  is  that  usually  met 
with  in  home-made  cells ;  the  writer  re- 
cently constructed  a  cell  along  these  lines 
with  a  resistance  of  but  200  ohms,  its  change 
of  resistance  was  approximately  20  ohms 
from  darkness  to  sunlight.  Naturally  this 
is  not  a  good  cell,  its  use  being  impractical 
since  the  variation  is  too  slight  to  make 
it  respond  to  small  changes  of  light  inten- 
sity. 

To  overcome  this  state  of  affairs  a  Bid- 
well  cell  was  made  as  shown  in  Fig.  2. 
In  this  case  four  wires  were  wound  on 
the  porcelain  support.  Two  of  these  were 
bare  and  formed  the  terminals  for  the  cell, 
the  other  two  were  enameled  and  were 
dead-ended.  The  selenium  being  applied 
over  the  wires  could  not  get  between  them 
and  in  this  way  the  area  of  the  light-af- 
fected part  formed  a  fairly  large  part  of 
the  total  conducting  area.  This  type  of 
construction  is  satisfactory  for  general 
work,  its  ratio  rarely  exceeding  5  to  1, 
however,  and  the  resistance  is  fairly  high. 
This  can  be  reduced  to  a  certain  extent 
by  using  fine  wires,  say  No.  32  B.  &  S. 
{Continued  on  page  332) 


RUNNING  SMALL  D.C.  MOTORS 
ON  A.C. 

Below  is  given  a  method  which  I  find 
useful  in  running  D.C.  motors  on  A.C.  cir- 
cuits. 

Disconnect  the  field  winding  from  the  ar- 
mature and  connect  the  brushes  (b)  of  the 


A  Plan  Whereby  a  Small  D.C.  Motor  Can  Be 
Operated  As  a  "Repulsion"  Type  Motor  On 
A.C.   Circuits.     Shift   the   Shorted  Brushes 
Until  Best  Results  Are  Obtained. 

armature  (a)  together.  Then  connect  the 
field  (F)  in  series  with  a  variable  resist- 
ance (R)  and  the  source  of  current.  The 
resistance  should  be  low  for  starting,  but 
may  be  increased  when  the  motor  is  under 
full  speed. 

Contributed  by  RAE  GALUSHA. 


A  VARIABLE   RESISTANCE  GAL- 
VANOMETER SHUNT. 

This  galvanometer  shunt  consists  of  a 
baseboard  4"  x  6"  x  1"  mounted  on  feet 
made  of  two  strips  of  half-inch  dowel  pin, 
each  4"  long.  Bore  holes  for  the  binding- 
posts  and  mercury  cups,  as  shown  in  the 
accompanying  sketch.  Put  all  screws, 
washers,  etc.,  in  place  and  then  solder  in 
the  resistances  and  connections. 

The  resistances  are  best  made  of  No.  22 
double-cotton  insulated  German  silver  wire, 
which  runs  nearly  one  ohm  per  foot. 
Relative  values  1:2:4  for  the  resistance 
coils  are  convenient.  These  used  singly, 
or  two  or  three  in  series,  will  give  a  wide 
range  of  combinations. 

The  actual  resistance  of  these  coils  will, 
of  course,  depend  upon  the  resistance  and 
sensitiveness  of  the  galvanometer. 


Res  coils 


Mercury  cups  t 


Simple  and  Efficient  Variable  Shunt  for  Use 
With    Galvanometers,    Employing  Mercury 
Switch. 

Short  pieces  of  heavy  copper  wire  bent 
to  connect  two  adjacent  mercury  cups  are 
used  for  short-circuiting  the  coils  when 
not  in  use. 

Contributed  by  PETER  J.  M.  CLUTE. 


326 


THE  ELECTRICAL  EXPERIMENTER 


September,  1917 


Making  an  Electric  Clock 


c 


OME  on  now,  "Bugs,''  roll  up  your 
sleeves,  sit  down  on  anything  you 
aren't  supposed  to  sit  on,  like  the 
bench  or  the  top  of  the  tool-cup- 
board, and  I'll  tell  you  how  to  make 
clock.     ("High  time  he  did,"  they 


Suspension  post  ' 
-  Suspension  spr/ng 
Hook  -  ":  "" 


-Pegu /a for 


'C/vss-seef/of? 

of  rod 


Confucf 


Bob 


f/g.2 


Several  Important  Details  of  the  Electric  Clock  Are  Here 
Illustrated,  Showing  Among  Other  Things  the  Particular  Man- 
ner of  Suspending  the  39-Inch  Pendulum  and  Bob,  Also  the 
Electrical  Contact  Actuated  by  the  Swinging  Pendulum  Rod. 

In  a  mechanical  clock,  the  pendulum  is 
driven  by  the  wheelwork ;  but  in  an  electric 
clock  (of  the  Hipp  type  at  least;  see  page 
114,  June,  1917  issue)  the  pendulum  drives 
the  wheels.  This  is  an  advantage  (for 
"Bug"  purposes  at  any  rate)  because,  there 
being  no  heavy  power  on  the  wheel-train, 
it  can  be  made  very  light,  and  you  aren't 
ruined  by  a  rough  bearing  or  wobbling  gears 
as  long  as  they're  true  enough  to  keep  in 
mesh. 

In  my  clock  (which  has  an  unnecessarily 
heavy  wheelwork)  the  pendulum  receives  an 
impulse  once  every  6  or  8  seconds,  when  the 
dry-cell  is  fresh.  The  interval  diminishes 
as  the  battery  runs  down,  till  just  before  it's 
played  out  it  receives  the  feeble  impulse 
every  2  seconds.  One  dry-cell  will  run  the 
clock  for  7  or  8  months ;  I  usually  put  on 
two  cells  in  parallel,  which  run  it  practically 
just  twice  as  long,  or  from  14  to  16  months. 

Almost  all  the  energy  is  used  up  in  driv- 
ing the  wheelwork.  With  the  pendulum 
swinging  alone,  it's  really  surprising  how 
little  power  is  required ;  a  single  impulse 


By  THOMAS  REED 

Part  1— The  Pendulum 

of  the  magnet  will  drive  it  from  5*  to  10 
minutes — minutes,  not  seconds.  You  know 
the  pendulum  is  theoretically  a  perpetual- 
motion  machine,  and  but  for  friction  and 
air-resistance  would  swing  forever  if  once 
started.  On  this  basis,  one  cell  would  keep 
the  pendulum  going  for  about  38  years,  if 
it  could  stand  up  that  length 
of  time.  Wish  it  would,  and 
that  were  all  there  was  to 
it !  You  could  hitch  on  a 
cell  when  the  baby  was  born, 
and  leave  it  to  him  to  pay 
for  the  next  one  when  he 
reached  middle  -  age  —  pro- 
vided he'd  laid  by  enough  of 
the  old  healthy  "mazuma"  in 
the  meantime;  some  of  us 
don't.  But  of  course  a  pen- 
dulum alone  doesn't  make  a 
clock,  any  more  than  one 
swallow  makes  a  —  drink; 
it's  useless  to  measure  the 
time  unless  you  record  the 
measurement. 

All  the  same,  if  any  of  you 
"Bugs"  start  a  clock,  I'd 
recommend  you  to  make  the 
pendulum  and  its  apparatus 
first,  and  get  it  going  nicely 
before  you  begin  the  wheel- 
work.  It's  easier  on  battery- 
finances,  for  one  thing.  Bat- 
tery upkeep  used  to  be  quite 
a  factor  in  my  young  days, 
and  in  my  efforts  to  keep  the 
upkeep  down  I  experimented 
quite  largely,  and  invented 
a  new  form  of  battery  which 
I  explained  at  some  length 
in  the  August  issue. 

So  now  about  the  pendu- 
lum. Fig.  1  shows  it  at  the 
end  of  the  right  oscillation, 
just  as  the  contact  is  made. 
The  departure  from  the  per- 
pendicular is  exaggerated. 
The  amplitude  should  be 
kept  as  small  as  possible, 
and  depends  upon  the  size 
of  the  teeth  in  the  escape- 
wheel.  Of  course  you  can 
place  your  contact-post  and 
magnet  in  accordance  with 
the  degree  you  require. 

Begin  at  the  top  of  Fig.  1, 
with  the  suspension  -  post. 
This  is  a  plain  brass  rod, 
say  y2"  diam.,  attached  to  the  back-board 
by  a  machine-screw  thru  the  back,  or  bet- 
ter attached  to  a  base-plate  and  screwed 
on  from  the  front.  It  ought  to  be  very 
strong  and  solid,  as  the  slightest  wiggle  will 
throw  your  time  all  out  of  gee.  It  has  a 
perpendicular  slit  in  front,  into  which  you 
poke  the  suspension-spring  and  pin  it. 

The  suspension-spring  you  can  make 
easily  enough,  if  you  want  to.  It's  simply 
a  piece  of  flat  steel  spring  like  a  watch- 
mainspring,  with  a  hole  in  each  end  for  a 
pin.  But  it  hardly  pays  to  make  it,  for  you 
can  buy  one  for  a  nickel  or  so  at  any  clock- 
store,  much  thinner  than  watch-mainspring 
(of  course  the  thinner  it  is  the  better)  and 
with  neat  brass  ends.  You  can  get  big 
ones,  but  the  little  ones  made  for  mantel 
clocks  are  all  right.  Don't  be  afraid  if  it 
looks  small;  I  had  a  20-lb.  pendulum  once 
hanging  on  one  of  those.  Only  be  sure 
that  your  hanging-pins  go  thru  the  steel 
itself,  as  on  these  light  springs  sometimes 
the  brass  ends  are  only  pinched  on.  An- 


a  home-made  one,  especially  if  thinned  by 
filing,  is  apt  to  have  inequalities,  which 
make  your  pendulum  wobble. 

Now  then,  your  pendulum  rod.  Thank 
heaven  in  this  case  the  best  is  the  cheapest, 
for  it's  recommended  to  be  made  of  or- 
dinary white  pine,  on  account  of  its  light- 
ness. That's  on  the  theory  of  concentrating 
all  the  weight  possible  in  the  bob,  but  it 
isn't  much  more'n  a  theory;  if  you'd  rather 
have  a  nice  pretty  mahogany  or  rosewood 
rod,  go  to  it.  If  you  have  a  pine  rod,  paint 
it  black  and  shellac  it  to  keep  the  moisture 
out. 

A  good  size  for  the  rod  is  3/4"  wide  by 
1/4"  thick,  and  it's  planed  down  rounding 
to  an  edge  till  it  has  a  cross-section  like  a 
lens.  This  is  only  theoretical  too,  in  order 
to  cleave  the  air  better ;  a  square-cornered 
one  will  do  about  as  well. 

At  the  top  of  the  rod  you  saw  down  a 
slit  and  set  in  a  piece  of  thick  sheet  brass, 
bent  into  hooks  as  shown  in  Fig.  2,  to 
hang  on  the  pin  of  your  suspension-spring. 
This  enables  you  to  take  the  pendulum  off 
more  easily  than  drawing  out  a  pin.  You'll 
have  occasion  to  take  it  off  quite  a  few 
times,  you  know,  before  it  starts  on  its  50- 
year  non-stop  run. 

At  the  bottom  of  the  rod,  drill  a  hole 
lengthwise  (and  for  the  love  of  Mike,  drill 
it  straight!)  and  screw  in  a  length  of  8-32 


other  reason  for  buying  your  spring  is  that 


Showing  How  the  Pendulum  Actuating  Mag- 
net Is  Mounted  So  as  to  Be  Readily  Ad- 
Justed.  It  Pays  to  Make  All  of  These  Parts 
Right,  Especially  the  Pole-pieces  or  Faces 
of  the  Magnet  Poles.  The  Magnet  Coils  Are 
Periodically  Excited  from  a  Battery. 


September,  1917 


THE  ELECTRICAL  EXPERIMENTER 


327 


screw  wire  for  the  regulating  nut  and 
armature. 

The  length  of  a  seconds-pendulum  (for 
mean  solar  time)  is  39.1  inches  from  the 
middle  of  the  suspension-spring  to  the  mid- 
dle of  the  bob;  so  you  won't  know  how  long 
to  have  it  unless  you  make  your  bob  first. 


The    Electric    Clock    Problem    Was  Finally 
Solved    by    Resurrecting    Hipp's  Pendulum. 
This  Design  Seemed  to  Work  the  Best. 


The  bob  can  be  any  size,  shape  or  weight, 
but  practically  should  be  a  symmetrical  fig- 
ure, and  the  heavier  it  is  the  better.  It 
takes  no  more  power  to  drive  a  heavy  one 
than  a  light  one,  and  the  heavy  one  eats  up 
some  slight  temporary  disturbances. 

The  cylindrical  bob  is  easiest  to  make. 
Use  a  brass  tube  about  6"  long  and  2"  in 
diameter.  Make  an  extra  foot  of  wooden 
rod  the  same  shape  as  your  pendulum-rod 
but  a  little  larger.  Stick  this  rod  up  per- 
pendicularly in  a  pailful  of  sand,  having 
the  surface  of  the  sand  packed  hard  and 
smooth.  Set  your  brass  tube  down  over 
the  rod  till  it  rests  on  the  sand,  being  sure 
that  your  rod  comes  exactly  in  the  middle 
of  the  tube  (top  and  bottom)  and  projects 
out  an  inch  or  so  at  the  top.  Now  pack 
more  sand  around  the  tube,  to  hold  it  dur- 
ing the  pouring  process  and  stop  the  lead 
from  running  out  the  bottom. 

Melt  up  some  scrap  lead,  but  don't  get  it 
too  hot — not  redhot,  just  hot  enough  to  run 
freely  and  show  up  shiny.  Pour  it  in  till 
the  tube  is  full,  and  stand  by  to  pour  a 
little  more  as  it  shrinks  on  cooling.  Your 
wooden  core  will  smoke,  but  let  it  smoke ; 
a  charcoal  core  is  just  as  good  as  a  wooden 
one,  and  comes  out  easier.  When  cold, 
drive  it  out,  and  your  bob  is  done,  except 
for  polishing  and  lacquering. 

The  bob-regulating  nut  should  have  a 
good  large  diameter  as  the  heavy  bob  takes 
some  power,  and  besides  it's  easier  to  see 
how  much  you've  turned  the  nut. 

The  armature  is  at  the  very  bottom  of  the 
rod,  and  is  simply  an  iron  disc  of  good 
thickness  and  about  3/4"  diameter.  It's 
screwed  up  on  your  bob-screw  and  held  fast 
by  a  check-nut  on  top  (here's  where  that 
ever-faithful  dry-battery  nut  comes  in).  If 
you  look  in  the  box  at  the  hardware-store 
where  they  keep  the  thumping  big  washers, 
you'll  probably  find  some  punchings  from 
the  inner  holes,  which  are  just  the  thing 
for    armatures.     I    imagine    the  wicked 


washer-makers  adulterate  their  goods  with 
as  many  of  these  useless  punchings  as  they 
dare,  to  the  woe  of  the  hardware-man ;  but 
it's  an  ill  wind  that  blows  nobody  good, 
and  we  should  worry  about  tainted  punch- 
ings. 

The  magnet  needs  pole-pieces  as  shown 
in  Fig.  4,  and  the  illustration  gives  what 
I've  found  to  be  a  very  good  adjustable 
mounting.  I  use  a  magnet  with  coils  about 
1"  diam.  by  XYi"  long,  wound  with  No.  24 
wire;  I  imagine  the  entire  magnet  measures 
about  20  ohms. 

The  Hipp-pattern  contact  was  described 
in  a  previous  article,  but  if  the  Editor 
please,  we'll  have  the  illustration  again  here 
(Fig.  3)  in  order  to  get  everything  to- 
gether. The  contact  is  mounted  on  a 
screw-post  (Fig.  5)  with  nuts  front  and 
back,  in  order  to  adjust  the  trigger  to  the 
notch  very  finely,  and  also  the  distance 
from  the  backboard,  as  the  contact  and 
magnet  have  to  be  in  the  same  plane  as  the 
pendulum. 

I  past  up  for  the  moment  the  rinktum 
shown  near  the  top  of  the  pendulum,  that 
looks  like  a  flower-pot  with  a  dead  begonia 
in  it.  (Figs.  1  and  6.)  That's  the  precision- 
regulator.  You  could  never  train  a  clock 
down  to  seconds-a-day  if  every  time  you 
regulated  it,  you  had  to  stop  the  pendulum 
and  screw  the  bob  up  and  down  ;  besides 
a  32  screw  isn't  fine  enough.  You  must 
have  some  means  of  changing  the  rate  of 
the  pendulum  without  stopping  it,  and  that 
with  extreme  delicacy,  as  any  change  you 
make  accumulates  till  after  the  86,400  sec- 
onds in  a  single  day  it  shows  up  big.  So 
you  first  attach  a  little  brass  cup  to  the 
pendulum  (Fig.  6)  about  a  third  of  the  way 
down  from  the  top,  and  put  in  it  a  dozen 
or  so  pieces  of  about  No.  24  wire,  long 
enough  to  project  well  out  of  your  cup,  so 
you  can  get  hold  of  them  easily  with  your 
fingers.  Now  you  regulate  your  pendulum 
by  the  bob-screw  till  you  get  it  fairly  good, 
say  to  half  a  minute  a  day;  after  that,  you 
regulate  by  taking  wires  out  of  the  cup,  or 
putting  more  in,  as  the  case  may  be.  Your 
hand  can  follow  the  motion  of  the  pendu- 
lum easily  enough,  especially  as  the  oscil- 
lation is  short  up  near  the  top,  so  you 
don't  have  to  stop  it.  The  more  you  load 
the  cup,  the  faster  the  pendulum  will  beat, 
which  is  opposite  to  what  you  might  sup- 
pose ;  but  the  weight  above  tends  to  make 
a  shorter  and  quicker  pendulum  theire, 
which  shortens  the  net  oscillating  length  of 
the  whole.  As  you  get  nearer  to  seconds-a- 
day  you  can  use  pieces  of  finer  and  finer 
wire,  till  finally  you  reach  the  point  where 
the  erratic  changes  exceed  your  regulation. 

[Watch  for  the  next  paper  describing  the 
wheel-work  in  the  October  issue.} 

HOW  TO  POLISH  HARD  FIBER. 

Hard  fiber  is  used  to  a  larger  extent  by 
amateurs  in  making  wireless  and  electrical 
apparatus,  but  it  has  the  disadvantage  of  ab- 
sorbing moisture  and  soon  becoming  a  poor 
insulator.  To  overcome  this  difficulty  I 
used  the  following  method:  After  the  fiber 
has  been  cut  to  size,  sand-papered  smooth 
and  all  holes  drilled,  soak  a  piece  of  waste 
in  thin  white  shellac  and  place  on  the  center 
of  a  piece  of  cloth  which  has  been  soaked 
in  boiled  linseed  oil.  Then  bring  the  edges 
of  the  cloth  up  around  the  waste  and  twist 
up  tight  until  the  shellac  begins  coming 
thru  the  cloth.  Then  rub  the  fiber  firmly 
but  rapidly  with  a  circular  motion,  and  con- 
tinue rubbing  until  the  shellac  begins  to 
get  sticky.  Do  not  stop  with  the  cloth  rest- 
ing on  the  fiber  as  it  is  apt  to  leave  a  spot. 
Before  the  polish  is  put  on  the  fiber  should 
be  left  in  a  warm  dry  place  for  a  day  or  so 
to  expel  all  moisture.  After  one  layer  has 
dried,  the  fiber  may  be  rubbed  with  fine 
steel  wool  and  another  coat  of  polish  put 
on.    About  three  or  four  coats  should  give 


a  fine  mirror-like  polish.  This  is  the  way 
the  finish  is  put  on  pianos,  etc.,  and  if  the 
experimenter  is  careful,  he  should  be  able 
to  attain  good  results  after  a  few  trials. 
To  keep  the  moisture  out  the  fiber  should 
of  course  be  covered  completely  with  the 
polish. 

Contributed  by        E.  C.  SCHURCH. 

A  HOME-MADE  "MAGNETIC" 
WINDOW  ATTRACTION. 

This  window  attraction  is  suitable  for 
a  tobacconist's  or  other  shop  and  never 
fails  to  attract  the  passers-by,  who  try  to 
solve  the  riddle.  The  effect  produced  is  as 
follows :  A  glass  dish  "A"  is  resting  on 
three  glass  knobs  "C,"  which  in  turn  are 
supported  by  a  small  wooden  box  "D." 

About  half  a  dozen  cigarettes  are  lying  in 
the  glass  dish.  Suddenly  the  cigarettes  rise 
on  end  and  are  standing  nearly  vertically 
for  a  few  moments,  then  they  fall  back 
again.  This  is  repeated  for  any  length  of 
time. 

The  cigarettes  cannot  be  operated  by 
threads,  as  they  roll  about  when  they  drop 
back  again,  and  as  the  dish  is  supported 
by  three  glass  knobs,  the  average  spectator 
does  not  think  it  likely  that  the  cigarettes 
are  operated  from  below. 

But  they  are ! 

The  box  contains  a  powerful  electro- 
magnet which  consists  of  an  iron  core  "F" 
and  the  winding  "E."  This  electro-magnet 
is  connected  in  series  with  a  Thermo-blink 
flasher  and  three  carbon  filament  lamps. 
The  latter  are  connected  in  parallel.  When 
the  current  is  thrown  on,  the  iron  core  "F" 
will  be  magnetized  by  the  coil  and  attract 
the  cigarettes. 

These  cigarettes  are  of  special  construc- 
tion and  consist  of  a  wooden  part  "G,"  and 
a  steel  part  "F."  The  latter  is  made  from 
a  wire  nail  about  lA  inch  diameter  by  Yn 
inch  long. 

The  wooden  part  is  hollow  so  as  to  make 
the  cigarette  dummy  rise  easily  when  the 
current  magnetizes  the  core  "F." 

After  the  current  has  been  passing  thru 
the  circuit  described  above  for  a  short  time 
the  Thermo-blink  flasher  breaks  the  cir- 
cuit only  to  close  it  again  in  a  few  seconds. 

Three  lamps  are  placed  in  parallel  so  as 
to  get  the  greatest  amperage  possible,  and 
for  the  same  reason  carbon  filament  lamps 
were  chosen. 

The  iron  core  was  made  of  a  short  piece 
of  mild  steel  shafting,  3  inch  diameter.  It 
was  thoroly  annealed  before  being  used,  so 
as  to  keep  the  residual  magnetism  as  small 
as  possible. 


Class d/sh 


Main 


Lamps 


^55 


-CKh 


f/asfie/- 


mm 


Section  //?rv  C/yaret/e 


Details  for  Making   the  "Magic  Cigarettes" 
Electrical  Window  Attraction.     It  Also  Pro- 
vides  Plenty  of  Mystery  for   Parlor  Enter- 
tainments. 

The  magnetizing  coil  "E"  consisted  of 
about  200  turns  of  No.  14  gage,  double  cot- 
ton covered  copper  wire.  "G"  is  a  wooden 
block  to  hold  "F"  in  position.  The  con- 
necting wires'  should  be  led  thru  the  bot- 
tom of  the  box  to  render  them  as  inconspic- 
uous as  possible. 

Contributed  bv       C.  A.  OLDROYD. 


328 


THE  ELECTRICAL  EXPERIMENTER 


September,  1917 


A  SMALL  WATER  MOTOR  FOR 
DRIVING  DYNAMOS. 
By  W.  E.  Leach. 

A  water  motor,  owing  to  the  variety  of 
uses  it  may  be  put  to,  will  find  ready  call 
among  experimenters.  It  is  not  at  all  diffi- 
cult to  construct  and  below  I  describe  one 


Construction  Details  for  a  Small  Water  Mo- 
tor  Which    Will    Prove    Useful    In  Driving 
Dynamos  or  Other  Light  Machinery. 


that  I  made  and  used  successfully  to  drive 
a  dynamo,  sharpen  tools,  as  a  drill,  and 
also  as  a  small  lathe. 

The  first  thing  to  obtain  is  the  materials. 
These  consist  briefly  of  the  following: — 1 
piece  2"  x  8"  x  10"  plank  (hard  wood), 
2  pieces  1"  x  8"  x  10"  board  (pine),  some 
Va"  x  y2"  board  (soft  or  hard  wood) — 7 
5"  x  3/16"  bolts,  4  ty2"  x  3/16"  bolts,  1 
piece  brass  tubing  y2"  in  diameter,  2}4" 
long  (for  nozzle). 

To  begin  with,  cut  a  case  from  the  piece 
of  plank  as  shown  in  Fig.  1  A  and  B.  Bore 
seven  *4"  holes  thru  this  as  shown.  At  the 
bottom  bore  a  1*4"  hole  for  an  outlet.  Then 
at  the  top,  bore  a  y2"  hole  about  12°  to 
the  horizontal ;  this  is  the  inlet.  The  ro- 
tating section  is  made  up  as  shown  in 
Fig.  2  A  and  B.  The  vanes  or  paddles  are 
cut  from  l/2"  boards  and  of  dimensions 
shown.  They  are  hollowed  out  at  the  ends 
and  are  set  into  an  axle  cut  from  a  piece 
of  hard  wood  1^4"  x  2"  with  a  hole 
thru  the  center. 

To  make  the  nozzle  take  the  piece  of 
brass  tubing  above  mentioned  and  solder 
to  it  a  cone  shaped  piece  of  tin  as  in  Fig. 
3 — A.  Now  drive  this  into  hole  at  top 
of  case  until  its  tip  first  comes  to  the  in- 
ner edge. 

Now  for  the  sides,  cut  two  pieces  out  of 


1"  pine  as  shown  in  Fig.  4.  Bore  7  %" 
holes  thru  these  to  correspond  to  those 
in  the  case  (Fig.  1).  At  the  center  bore 
a  1"  hole,  and  about  1"  away  from  the 
center  in  a  perpendicular  line,  drill  one  %" 
hole  on  each  side  of  this  as  shown.  Now 
make  two  plates  3"  in  diameter  and  J4" 
thick  as  shown  in  B  (Fig.  4).  Bore  a  *4" 
hole  in  the  center  and  about  1"  to  either 
side  bore  another  J4"  hole.  Make  two 
plates  of  iron  as  in  Fig.  3— B.  Drill  holes 
to  correspond  to  those  in  the  plates,  Fig. 
4— B. 

Give  all  parts  two  coats  of  good  water- 
resisting  paint  and  when  dry  assemble  as 
follows: — Place  a  plate  (Fig.  4— B)  on  the 
outside  of  the  sides,  put  a  wad  of  packing 
soaked  in  oil  in  the  1"  hole.  Then  -place 
an  iron  strip  (Fig.  3 — B)  on  the  inside  of 
each  side  and  bolt  firmly  together  with  two 
V/2"  x  3/16"  bolts.  Drive  a  shaft  thru 
the  rotating  part.  Insert  one  end  of  shaft 
thru  one  side  and  then  place  inside  of 
case.  Put  the  7  5"  x  3/16"  bolts  thru  and 
fasten  the  other  side  together.  (In  setting 
up,  if  some  pitch  is  placed  between  the  sides 
and  case  it  will  prevent  any  leakage.)  Con- 
nect the  motor  to  any  faucet  by  a  rubber 
hose  and  it  is  ready  for  work.  If  all  parts 
were  smooth  and  bored  and  cut  accurately, 
little  trouble  will  present  itself  and  the 
motor  will  go  buzzing  around  at  first  con- 
nection. 

X-RAY  TUBES  FOR  HIGH-FRE- 
QUENCY COILS. 

(Continued  from  page  309) 

It  is  really  a  combination  of  two  dis- 
tinct tubes,  as  indicated  by  the  heavy  ver- 
tical dotted  line.  When  the  current  passes 
in  the  direction  of  the  arrow  (b)  X-rays 
are  produced  from  the  cathode  and  target 
(c  and  d)  in  the  righ-hand  half  of  the 
tube ;  alternations  in  the  opposite  direc- 
tion, indicated  by  the  arrow  (a),  produce 
a  stream  of  rays  from  the  left  half  of 
the  tube.  This  is  the  most  efficient  form 
of  high-frequency  X-ray  tube,  as  it  uses 
both  sets  of  alternations.  It  is  now  prac- 
tically obsolete,  however,  as  it  was  found 
that  the  two  sets  of  X-rays  overlapt  and 
produced  double  outlines  in  the  skiagram. 

At  the  present  time  there  are  two  types 
of  X-ray  tubes  made  for  use  with  high- 
frequency  currents.  The  one  shown  in 
Fig.  3  has  a  target  of  heavy  copper  faced 
with  tungsten,  and  is  mounted  opposite  the 
active  cathode  (c)  ;  when  the  current  flows 
in  the  opposite  direction  the  electronic 
stream  from  the  small  cathode  (c1)  be- 
comes choked  out  and  dispersed  by  the 
constricted  glass  neck  (d),  which  acts,  in 
a  measure,  as  a  valve,  eliminating  the  in- 
verse discharge. 

Another  type  of  modern  high-frequency 
X-ray  tube  is  shown  in  Fig.  4,  in  which 
the  cathode  rays  from  the  small  aluminum 
mirror  (c1)  focus  inside  a  small  copper 
cone  (d),  in  which  they  are  converted  into 
heat  and  take  no  part  in  the  production 
of  the  X-rays. 

Tubes  of  these  types  may  be  operated 
by  the  current  from  a  Tesla  coil  or  from 
an  Oudin  resonator.  In  a  previous  article 
in  the  May  issue  of  the  Electrical  Ex- 
perimenter the  writer  has  given  details 
for  the  construction  of  apparatus  of  both 
these  types. 

When  the  Tesla  coil  is  used  its  termi- 
nals are  connected  to  the  two  aluminum 
cathodes  (c  and  c1)  ;  the  Oudin  coil  has 
but  one  active  terminal  which  should  be 
connected  to  the  active  cathode  (c)  ;  the 
small  cathode  (c1)  may  be  grounded,  but 
this  is  not  absolutely  necessary. 

X-ray  tubes  are  spoken  of  as  "hard"  and 
"soft" — a  "hard"  tube  is  one  which  has 
been  exhausted  to  a  very  high  degree — 
(say,  one-ten-millionth  of  an  atmosphere) 
— a  "soft"   tube  has  a  lower   degree  of 


exhaustion  (between  one-five-hundred-thou- 
sandth and  one-one-millionth  of  an  atmos- 
phere). More  current  is  needed  to  oper- 
ate a  hard  tube,  but  it  gives  deep  pene- 
tration and  works  more  quickly.  The  soft 
tube,  on  the  other  hand,  produces  strong 
contrasts  in  the  skiagram  or  fluoroscope. 

Tubes  have  a  tendency  to  become  hard 
by  use,  the  trace  of  residual  air  or  gas 
being  gradually  driven  out  thru  the  in- 
termolecular  spaces  of  the  glass  by  the 
electronic  bombardment.  So  it  is  neces- 
sary to  provide  the  tube  with  some  means 
for  replacing  these  lost  ions  at  intervals. 
.  The  first  is  of  the  thermic  type  and  is 
now  seldom  used  (see  e,  Fig.  2)  ;  it  con- 
sists of  a  small  bulb  containing  potassium 
chlorat  sealed  into  the  side  of  the  X-ray 
tube.  By  heating  this  bulb  with  a  match 
or  spirit-lamp,  a  trace  of  oxygen  is  given 
off,  which  reduces  the  pressure  in  the  tube 
to  the  required  degree.  The  modern  high- 
frequency  tubes  use  the  forms  known  as 
the  "spark  regulator"  and  the  "osmotic 
regulator." 

The  first  is  the  more  common  type  and 
is  shown  in  (f,  Fig.  3).  A  platinum  wire 
is  sealed  in  the  regulator  tube  which  con- 
tains a  gas-producing  chemical,  such  as 
manganese  dioxid,  or  sodium  formate,  f. 

In  practise  a  piece  of  E-shaped  stiff 
brass  wire  set  in  a  rubber  handle  is  used 
to  divert  a  portion  of  the  current  from 
the  active  terminal  to  the  wire  in  the  regu- 
lator ;  the  heat  from  the  current  liberating 
the  gas  and  softening  the  tube. 

A  regulator  of  the  osmotic  type  is  shown 
at  (g,  Fig.  4).  It  consists  of  an  extremely 
small  tube  of  metallic  palladium  sealed 
into  the  side  of  the  X-ray  bulb,  the  inner 
end  of  the  metal  tube  being  open  while 
the  outer  end  is  closed.  Ordinarily  the 
tube  is  protected  by  a  cylindrical  glass  cap. 
If  the  latter  be  removed,  and  the  flame  of 
a  spirit-lamp  be  applied  to  the  closed  ex- 
tremity of  the  palladium  tube,  hydrogen 
ions  from  the  interior  of  the  flame  will 
be  drawn  thru  the  intermolecular  spaces 
of  the  heated  metal  into  the  X-ray  bulb. 

Amateurs  and  physicians  using  X-ray 
outfits  often  desire  to  view  considerable 
areas  of  the  body  simultaneously;  this  can 
be  done  only  by  using  a  large  fluorescent 
screen  and  covering  the  X-ray  tube  with 
opaque  material.  Ordinary  fluoroscopic 
screens  are  coated  with  barium-platinum- 


One  Form  of  Commercial  High-Frequency 
X-Ray  Bulb  of  the  Single-focus  Type,  Utiliz- 
ing An  Active  Cathode  "C",  Also  a  Small 
Cut-off  Cathode  "C1".  The  Inverse  Cath- 
odic  Stream  from  "C1"  Is  Choked  Off  and 
Dispersed  by  the  Constricted  Glass  Neck 
"D",  Which  Acts  As  a  Valve. 

cyanid  and  cost  about  $0.25  per  sq.  inch. 
A  very  good  screen  may,  however, 
be  easily  made  by  evenly  coating  a  sheet 
of  white  cardboard  with  a  solution  of 
sodium  silicat  and  immediately  sifting  on 
it  finely  powdered  calcium  tungstat.  Gent- 
ly raise  the  screen  on  its  edge  and  tap  it 
to  shake  off  the  excess  of  tungstat;  then 
allow  to  dry.  A  still  simpler  experimental 
screen  may  be  made  by  painting  a  card 
several  times  with  a  strong  solution  of 
quinine  bi-sulfate. 


September,  1917 


THE  ELECTRICAL  EXPERIMENTER 


329 


A  Home-Made  Arc  Search-Light  for  the  Amateur 


THE  arc  search-light  here  shown  and 
described  when  properly  constructed 
and  focused,  is  capable  of  projecting  a 
powerful  beam  that  can  be  seen  for  several 
miles  around.  The  amateur  will  find  it  very 
interesting,  to  pick  out 
distant  objects  as  well 
as  passing  pedestrians 
and  vehicles.  The  ma- 
terials required  are 
few,  most  of  which 
are  found  around  the 
amateur's  home.  The 
search-light  is  not  dif- 
ficult to  construct  and 
is  quite  worth  the 
effort. 

The  body  of  the 
searchlight,  A  (Fig. 
1)  is  a  large  syrup 
can,  7  inches  long  and 
b]/2  inches  in  diameter. 
No  other  size  can  will 
do  unless  the  carbon 
clamps  and  base  are 
made  to  correspond 
with  it.  The  venti- 
lation top,  V,  is  made 
from  tin,  cut  and 
bent  into  the  shape 
shown.  The  holes  are 
punched  to  allow  the 
heat  and  smoke  to 
escape.  Before  fast- 
ening it  to  the  can  a 
large  oblong  hole  is 
cut  directly  under  it. 
The  top  is  then  fast- 
ened on  with  small 
stove  bolts.  A  broom 
stick  fastened  to  the 
back  of  a  tin  strip, 
bent  into  a  sort  of  U 
shape,  bolted  to  the 
back  of  the  can,  forms 
a  handle. 

The  next  thing  to 
make  is  the  base.  A 
stand  taken  from  an 
old  electric  fan  is  just 
the  thing,  but  a  wood- 
en or  iron  one  with  the 

same  swivel  adjustment  can  be  easily  made 
and  will  well  serve  the  purpose.  In  Fig.  2 
the  wooden  one  is  shown  with  the  dimen- 
sions.    The   dotted   circle   represents  the 


By  FRANK  M.  JACKSON 

is  next  fastened  to  the  rear  end  of  the 
search-light.  This  mirror  reflects  the  light 
from  the  arc  and  sends  out  a  beam  greatly 
intensified. 

Great  care  must  be  taken  in  the  construc- 


Appearance  and  Detail  of  Arc  Carbon  Holder  for  Experimental  Search- Light.  Many 
Scientific  as  Well  as  Practical  Uses  Can  be  Found  for  Such  a  Device,  Including  the 
Stunt  of  "Talking  Over  a  Beam  of  Light." 

tion  of  the  clamps,  which  are  to  hold  the 
carbons,  to  follow  the  dimensions  correctly. 
The  wooden  base,  B,  Fig.  3,  is  5^4x1x^2 
inches.  First  cover  it  all  over  with  a  thin 
piece  of  asbestos.  Next  a  strip  of  tin  is 
fastened  around  the  left  hand  end  of  the 
base  and  runs  3A  of  the  way  to  the  other 
end.  Then  a  small  space  %  inch  is  left  so 
that  the  tin  strip  on  this  end  will  not  short- 
circuit  with  the  strip  on  the  other  end.  A 
small  piece  of  tin  is  put  on  the  right  hand 
end,  the  same  as  the  left,  but  much  shorter. 
The  clamp  at  the  left  hand  end  is  adjusta- 
ble. It  should  slide  easily  over  the  tin  strip 
on  the  base.  It  is  made  from  tin  cut  and 
bent  around  the  carbon  and  base  and  then 


fastened  onto  each  side  of  the  block,  D, 
which  is  Ixlxyi  inches  and  is  covered  with 
asbestos  and  tin.  To  this  block  is  also 
fastened  the  handle,  H,  with  the  hard  rub- 
ber knob  on  the  end.  The  clamp  at  the 
right  is  stationary 
and  is  fastened  to  the 
base.  The  clamps 
should  each  be  2^4 
inches  high.  A  stick 
of  carbon  Yz  inch  in 
diameter  and  12  in- 
ches long  may  be  pro- 
cured from  a  store 
dealing  in  electrical 
goods  for  only  five 
cents.  It  is  broken 
into  four  equal  pieces 
to  put  into  the  clamps 
and  held  into  position 
by  the  screws,  S  and 
S.  Put  a  nail,  N  into 
the  right  hand  end  of 
the  base. 

The  next  thing  to 
do  is  to  put  the  clamps 
into  the  search  -  light 
can.  The  best  way  to 
find  the  position  for 
the  proper  focus  is  by 
holding  a  candle  at 
different  distances 
from  the  reflector. 
When  the  smallest 
spot  is  projected  this 
is  the  best  focus. 
Mark  this  position  and 
put  the  clamps  in  as 
shown  in  Fig.  3,  with 
the  nail  at  the  right 
hand  end  and  the 
handle  at  the  left  go- 
ing thru  small  holes, 
one  in  each  side  of  the 
can.  If  desired  striped 
glass,  as  shown  in 
Fig.  1,  may  be  mount- 
ed on  a  hinged  door 
at  the  front  of  the 
searchlight,  but  is  not 
necessary.  The  search- 
light is  now  complete. 
A  suitable  resistance  to  operate  with  the 
searchlight  must  be  constructed.  This  re- 
sistance is  shown  in  Fig.  4.  The  two  ends 
are  each  4x12  inches  and  the  top  and  bot- 


Showing  the  Arc  Search-Light  Made  by  the 
Author,  Complete  with  Rheostat. 

front  of  the  can  and  shows  method  of  fast- 
ening it  to  the  base.  These  bolts  must  be 
loose  enough  to  permit  movement  up  and 
down.  Movement  from  side  to  side  is  al- 
lowed by  the  single  nail  shown  at  N,  Fig. 
2.  Next  procure  from  an  automobile  sup- 
ply house  or  garage  a  parabolic  reflector 
such  as  that  from  an  old  gas  lamp.  This 
should  be  about  6  inches  in  diameter.  It 


Connections  for  Miniature  Arc  Search-Light 
on  110  Volt  Circuit. 


How  Rheostat  Frame  Is  Made.  It  Should  be 
Constructed  of  Fire-Proof  Materials  Thruout. 

torn  are  each  4x18  inches.  After  screw- 
ing these  boards  together  as  shown,  they 
are  lined  inside  with  heavy  asbestos.  Pro- 
cure from  a  hardware  store  50  feet  of  No. 
18  soft  iron  wire,  which  will  cost  about 
five  cents.  Cut  the  wire  in  two  20  foot 
lengths  and  run  it  in  zig-zag  fashion  thru 
staples  in  two  rows  3  inches  apart,  the 
length  of  the  boards.  Fig.  4  shows  how 
the  wire  is  pulled  thru  the  staples  in  two 
(Continued  on  page  332) 


330 


THE  ELECTRICAL  EXPERIMENTER 


September,  1917 


raw 


This  department  will  award  the  following  monthly  prizes:    First  Prize,  $3.00;  Second  Prize,  $2.00;  Third  Prize,  $1.00. 

The  purpose  of  this  department  is  to  stimulate  experimenters  towards  accomplishing  new  things  with  old  apparatus  or  old  material, 
and  for  the  most  useful,  practical  and  original  idea  submitted  to  the  Editors  of  this  department,  a  monthly  series  of  prizes  will  be  awarded. 
For  the  best  idea  submitted  a  prize  of  $3.00  is  awarded;  for  the  second  best  idea  a  $2.00  prize,  and  for  the  third  best  prize  of  $1.00.  The  article 
need  not  be  very  elaborate,  and  rough  sketches  are  sufficient.  We  will  make  the  mechanical  drawings.  Use  only  one  side  of  sheet.  Make 
sketches  on  separate  sheets. 


SECOND  PRIZE,  $2.00 


FIRST  PRIZE,  $3.00 


THIRD  PRIZE,  $1.00 


AN  ELECTRIC  RAIN  ALARM. 

Take  an  ordinary  funnel,  either  glass  or 
tin,  and  fasten  it  into  place  where  the  rain 
can  get  into  it  easily  and  quickly.    Take  a 


1 

Wire  /oop  W_ 
fatfenaffo  — *W 
house  J 

/iWRy  funnel 

mm 

mm//  W/res 

■W  ,', 

To  baff.&  \ 
re/ay  \ 

An    Electric    Rain    Alarm    Is   of  Undoubted 
Value   in    Every    Home.     The    Rain  Water, 
Mixing  With  a   Few  Grains  of  Salt,  Closes 
the  Alarm  Circuit. 


cork,  or  preferably  a  rubber  stopper,  with 
two  wires  thru  it,  as  shown  in  the  diagram, 
and  insert  in  the  smaller  end  of  the  fun- 
nel. The  wires  should  be  only  a  small 
space  apart,  and  you  should  drop  a  little 
salt  into  the  funnel  to  make  the  water  a 
better  conductor. 

When  a  few  drops  of  rain  fall  into  the 
funnel  it  will  close  the  circuit  thru  a  relay 
and  battery,  thus  ringing  a  bell. 

Contributed  by  G.  C.  ZANKL. 


UNIQUE   EXPERIMENT  WITH 
MOTOR  AND  COMPASS. 

While  working  at  my  electrical  appa- 
ratus, I  picked  up  my  compass  and  placed 
it  near  a  screw-driver  not  thinking  that 


S.  Pole 


Compass 


Demagnetized  Compass  Needles  May  Be  Made 
As  Good  As  New  by  Simply  Placing  the  Com- 
pass Under  the  Field  Legs  of  a  Toy  Motor. 

it  would  injure  the  compass.  After  re- 
maining there  for  two  days,  it  drew  all  the 
magnetism  from  the  needle  of  the  compass. 
It  would  remain  in   any  position  that  I 


A  MAGNETICALLY  CONTROLLED 
OIL  CUP. 

An  electro  magnet  is  used  in  this  scheme. 
A  are  the  electric  wires,  D  is  a  round 
soft  iron  plate,  C  is  the  screw  rod,  E  is  an 
iron  cap  on  top  of  the  oil  feed  pipe  F. 

To  open  the  oil  cup  turn  on  the  electric 
current  and  iron  disc  D  becomes  magne- 
tized and  pulls  up  cap  E  on  top  of  oil  feed 
pipe  F,  and  the  oil  will  start  to  drip. 
When  the  current  is  shut  off  D  loses  its 
magnetic  power.  E  and  F  drop  down  and 
close  up  the  oil  hole  again.  To  regulate 
the  flow  of  oil,  B  is  turned  and  the  screw 
rod  C  raises  or  lowers  plate  D.    By  using 


Elecfro  - 
i  Yjjlrf-''' 'Magnet 


A  Practical  Application  of  the  Electro-mag- 
net,   Enabling   the   Engineer  to   Control  Oil 
Cups  At  a  Distance,  Also  in  Groups. 

a  small  solenoid  and  a  rheostat  the  control 
of  the  oil  cup  can  be  made  quite  precise. 
Contributed  bv 

OTTO  C.  HALSTRUM. 

placed  it.  making  it,  of  course,  useless.  I 
resolved  to  fix  it,  and  after  experimenting 
with  it  for  fully  an  hour,  succeeded  as  fol- 
lows :  I  placed  the  North  pole  of  my  toy 
motor  facing  North,  then  I  placed  the  com- 
pass under  the  field  coil  of  my  motor, 
which  I  put  in  operation  for  about  one 
minute,  after  which  it  served  as  a  new 
compass.  The  armature  should  be  left  out 
of  circuit. 

Contributed  by         JOHN  UEBLER. 


Due  to  the  advent  of  the  war,  we  are 
particularly  desirous  of  obtaining  manu- 
scripts describing  original  and  practical 
"Electrical  Experiments."  We  shall 
continue  to  publish  Radio  articles,  but 
what  we  need  is  snappy  "Electrical" 
articles.  Be  on  guard  for  the  enemy — 
Repetition! 


TIRE  PLUGS  AS  INSTRUMENT 
FEET. 

After  trying  out  various  anti-shock  feet, 
insulators,  etc.,  I  hit  upon  the  idea  of 
taking  a  rubber  bicycle  tire  repair  plug 
and  drilling  a  hole  in  each  corner  of  the 


A  New  Use  for  Rubber  Tire  Plugs  at  Last. 
Why   Not  Use  Them  for  Instrument  Feet? 
Too  Bad  Some  Genius  Can't  Find  an  Elec- 
trical Use  for  Old  Shoe  Nails. 

base  the  size  of  the  stem  and  gluing  the 
plug   fast.     This  makes  an  excellent  in- 
sulator as  well  as  silent  and  shock-proof 
foot.    (Ye  Gods!    Next!!  Editor.) 
Contributed  by  WILMER  J.  SLIFER. 


A  SIMPLE  TELEPHONE. 

The  accompanying  diagram  shows  a 
good  way  in  which  to  rig  up  a  telephone 
system  by  means  of  an  E.  I.  Co.,  Pony  re- 
ceiver which  may  be  used  as  a  telephone 
(both  for  transmitting  and  receiving)  up 
to  a  distance  of  150  feet  or  more.  For 
longer  distances  batteries  should  be  con- 
nected between  the  receiver  and  line  wire. 

After  the  stations  are  connected  as 
indicated,  one  station  may  ring  the  other 
by  removing  his  receiver,  the  weight  of 
which  has  kept  the  ground  wire  in  con- 
nection with  the  bell,  and  turning  the 
switch  handle  to  point  2  in  the  diagram. 
To  put  both  receivers  in  the  circuit  it  is 
necessary  to  throw  the  switch  back  on  point 


To  Make  This  Simple  Telephone  System  All 
You  Require,  Are  Two  75  Ohm  'Phones,  2  Call 
Bells,  2  Push  Buttons,  Batteries,  2  Switches 
and  a  Pair  of  Home-made  Hook  Switches. 

1.     The  weight  of  the  metal  hook  will 
cause  it  to  drop  to  the  lower  contact. 
Contributed  by  CLAUDE  IRELAND. 


September,  1917 


THE  ELECTRICAL  EXPERIMENTER 


331 


THE  FRANKLIN  EXPERIMENTAL 
CLUB. 

(Continued  from  page  311) 
vited  guests  and  members,  and  every  en- 
couragement was  given  to  original  experi- 
ments and  the  construction  of  original  ap- 
paratus and  for  some  time  it  was  a  rule 
that  each  member  must  perform  an  orig- 
inal experiment,  however  crude,  at  least 
once  a  month,  and  many  well-known  prin- 
ciples in  electricity,  magnetism,  sound, 
light,  chemistry,  etc.,  were  thus  demon- 
strated and  originality  and  initiative  stimu- 
lated. 

With  a  view  to  bringing  before  the  com- 
munity the  earnest  aims  and  accomplish- 
ments of  the  club,  an  elaborate  electrical 
dinner  was  given  on  January  31st,  1891, 
which  was  attended  by  Mayor  Haynes  of 
the  City  of  Newark;  Senator  M.  T.  Bar- 
rett; Supt.  of  Public  Schools,  W.  N.  Bar- 
ringer,  Sec.  of  the  Board  of  Education, 
Lyndon  Brice,  and  other  prominent  men, 
including  William  Wallace,  Edward  Wes- 
ton, Francis  R.  Upton,  Frank  J.  Sprague, 
James  M.  Beck  and  Richard  F.  Outcault. 
The  guests  were  entertained  by  electrical 
experiments,  and  many  novel  effects,  and 
regaled  with  food  and  coffee  cooked  by  elec- 
tricity. Cigars  were  lighted  by  electricity, 
for  there  were  no  matches  to  be  had,  and 
a  tiny  electric  railway  running  about  the 
table  carried  food,  cigars,  cigarettes,  etc., 
to  the  guests,  while  in  the  meantime  they 
were  entertained  with  instrumental  and 
vocal  music  rendered  by  a  young  lady  seated 
at  a  piano  a  block  away,  which  music  was 
transmitted  by  a  loud-speaking  telephone 
thru  a  trumpet  suspended  over  the  table ; 
from  this  trumpet  hung  a  circular  bomb, 
which  was  exploded  by  electricity  during 
the  feast,  bombarding  the  guests  with  bon- 
bons. 

A  number  of  electro-magnets  hung  sus- 
pended at  various  points  from  the  ceiling 
and  were  connected  in  series  with  the  light- 
ing circuit;  these  magnets  held  up  roses 
and  carnations  to  each  of  which  a  tiny  nail 
or  screw  had  been  attached,  so  that  when 
the  magnet  circuit  was  broken  the  guests 
were  treated  to  a  shower  of  beautiful 
flowers,  which  fell  all  over  the  table.  There 
were  bears,  alligators  and  storks  about  the 
table,  equipt  with  blinking  eyes  and  hold- 
ing electric  lamps  or  other  ornaments, 
while  real  gold  fish,  which  had  tiny  incan- 
descent electric  lamps  inside  their  stomachs, 
connected  by  thread-like  insulated  wires  to 
a  storage  battery  were  beautifully  illumi- 
nated from  time  to  time  in  the  darkened 
room  as  they  swam  about  in  a  huge  glass 
globe.  Near  the  center  of  the  table  were 
three  skulls  with  electric  lamps  blinking  in 
their  eyeless  sockets ;  they  rested  on  a  black 
velvet  pedestal  containing  a  concealed  pho- 
nograph and  frequently  during  the  meal 
the  guests  were  startled  by  a  sepulchral 
voice  emanating  from  the  skulls  which  said  : 
"As  ye  are  now,  so  once  were  we. 
As  we  are  now,  so  ye  shall  be." 

Perhaps  the  most  interesting  feature  of 
the  dinner  was  presented  in  a  life-sized 
wax  figure  of  Benjamin  Franklin  loaned 
by  the  "Eden  Musee,"  who  with  a  benig- 
nant smile  on  his  countenance,  sat  at  the 
head  of  the  long  table  and  presided  over 
the  feast ;  periodically  Franklin  who  held 
in  one  hand  a  kite  string  attached  to  a 
replica  of  Franklin's  kite  placed  in  the  far 
corner  of  the  ceiling  of  the  room,  would 
draw  a  long  flash  of  lightning  to  a  key 
held  in  the  other  hand  and  by  means  of  a 
phonograph  inside  of  his  anatomy,  he 
made  an  address  to  the  guests  as  fol- 
lows : 

"My  dear  Friends: — 

"Through  the  genius  of  Mr.  Thomas 
A.  Edison,  I  come  back  to  you  from  the 
past  of  over  a  century  ago.   I  am  glad  to 


find  I  am  so  well  remembered  and  I  am 
pleased  to  preside  at  this,  the  first  annual 
banquet  of  the  Franklin  Experimental 
Club  of  Newark,  New  Jersey. 

"Good  things  will  bear  repeating.  Let 
me  quote  some  expressions  of  mine,  which 
I  see  have  now  become  household  words 
of  yours. 

"  'Early  to  bed,  and  early  to  rise,  makes 
a  man  healthy,  wealthy  and  wise.' 

"'If  you  would  know  the  value  of 
money,  try  and  borrow  some.' 

"'When  the  well  is  dry,  they  know  the 
worth  of  water.' 

"  'Experience  keeps  a  dear  school,  but 
fools  will  learn  at  no  other.' 

"  'Now  I  have  a  sheep  and  a  cow,  every 
one  bids  me  good  morning.' 

"  'For  want  of  a  nail,  the  shoe  was 
lost;  for  want  of  a  shoe,  the  horse  was 
lost.' 

"  'Three  removes  are  as  bad  as  a  fire, 
and  a  rolling  stone  gathers  no  moss.' 

"  A  small  leak  will  sink  a  great  ship.' 

"  'What  maintains  one  vice  would  bring 
up  two  children.' 

"  'Industry  pays  debts,  and  despair  in- 
crcaseth  them.' 

'"Ahvays  taking  out  of  the  meal  tub, 
and  never  putting  in,  soon  comes  to  the 
bottom." 

"  'If  you  would  have  a  faithful  servant 
and  one  that  you  like,  serve  yourself.' 

"  'Sloth,  like  rust,  consumes  faster  than 
labor  wears,  while  the  used  key  is  al- 
ways bright.' " 

During  the  dinner  some  appropriate  re- 
marks bearing  upon  Franklin,  and  his 
work,  made  by  Mr.  Edison,  and  which  he 
had  personally  recorded  upon  a  phonograph 
cylinder  especially  for  the  occasion,  were 
listened  to  with  great  interest. 

At  the  center  of  the  table  stood  a  five- 
foot  reproduction  of  the  Eiffel  Tower, 
lighted  by  many  tiny  electric  lamps  with  a 
miniature  searchlight  on  top.  During  a 
sudden  darkening  of  the  room  the  model 
was  beautifully  illuminated  by  colored  fire 
set  off  by  electricity  on  the  various  plat- 
forms of  the  tower;  this  was  followed  by 
the  Marseillaise  sung  by  Mme.  Adini  and 
M.  Melchizdec  of  the  Grand  Opera,  Paris, 
rendered  by  a  phonograph  cylinder  made 
by  the  society's  president  in  M.  Eiffel's  pri- 
vate room  on  top  of  the  Eiffel  Tower  the 
day  the  Paris  Exposition  of  1889  closed. 

The  guests  also  listened  with  rapt  atten- 
tion to  the  voices  of  M.  Eiffel,  M.  Gounod 
and  others  shouting  "Vive  la  France," 
"Vive  la  Republique"  as  the  booming  of 
the  official  gun  stationed  on  top  of  the 
Eiffel  Tower  could  be  plainly  heard,  an- 
nouncing the  close  of  the  Paris  Exposition ; 
simultaneously  a  tiny  cannon  on  top  of  the 
replica  of  the  tower,  which  decorated  the 
table,  was  fired  off  by  electricity  and  the 
dinner  and  its  festivities  came  to  a  close. 
Each  guest  carried  away  as  a  souvenir  a 
medallion  of  Benjamin  Franklin,  on  the 
reverse  of  which  was  inscribed  data  re- 
garding Franklin,  and  the  Franklin  Ex- 
perimental Club. 

AN  EXPERIMENTAL  GEISSLER 
TUBE. 

The  best  results  and  effects  are  obtained 
with  discharges  from  the  secondary  of  an 
induction  coil  in  glass  tubes  when  the  ex- 
haustion is  carried  to  a  pressure  of  about 
2  mm.  of  mercury,  and  the  tubes  are  per- 
manently sealed. 

However  for  experimental  purposes  a 
Geissler  tube  made  as  described  below  gives 
most  satisfactory  results. 

Procure  a  glass  U-tube  about  34  inches 
high.  Fill  it  with  clean  mercury,  close  the 
ends  with  the  fingers  and  invert  it  into  two 
vessels  of  mercury.  Upon  removing  the 
fingers,  the  mercury  in  the  two  arms  will 
fall  a  few  inches,  as  shown  in  the  accom- 


panying sketch.  This  will  create  a  vacuum 
in  the  upper  part  of  the  tube,  known  to 
physicists  as  a  Torricellian  vacuum,  from 
Torricelli,  a  pupil  of  Galileo. 

Wires  are  led  from  the  mercury  cups 
to  two  binding-posts,  as  shown.  If  the  elec- 
trodes of  an  induction  coil  are  connected 
to  these  terminals,  a  luminous  phenomenon 


ueiosier    i  ubes   Are    Not   Always  Available 
When    Wanted.     Here's   the   Way  to  Make 
One  in  Your  Laboratory. 


is  produced  in  the  upper  section  of  the  tube. 

This  experiment  may  be  varied  by  care- 
fully admitting  different  gases  or  vapors 
into  the  evacuated  space.  The  luminous 
effects  obtained  thereby  are  very  beautiful. 
The  colors  are  determined  by  the  nature  of 
the  residual  gas.  Hydrogen  glows  with  a 
brilliant  crimson;  the  vapor  of  water  gives 
the  same  color,  indicating  that  the  vapor 
is  dissociated  by  the  discharge.  An  exam- 
ination of  this  glow  by  the  spectroscope 
gives  the  characteristic  lines  of  the  gas  in 
the  tube. 

Contributed  by  PETER  J.  M.  CLUTE. 
(Union  College,  Physics  Laboratory.) 


A  CONDENSER  SWITCH  OF 
PROVEN  EFFICIENCY. 

Here  is  a  small  (or  any  size  the  reader 
may  desire  to  make  it)  switch  for  use  on 
an  adjustable  condenser.  It  is  simply  built 
and  will  work  easily  without  getting  out 
of  order  readily. 

It  is  made  from  a  fiber  washer  and  half 
of  a  brass  washer,  fitted  so  there  will  be 
an  even  surface  as  shown.  The  contacts 
are  made  from  brass  strips  cut  and  bent 
into  shape.    For  a  handle  an  old  typewri- 


lf   Properly   Made  This   Form  of  Condenser 
Switch   Will  Give  the   Best  of  Satisfaction. 
Bend  the  Contact  Springs  So  They  Do  Not 
Catch  on  the  Disc  Edge. 


ter  knob  will  do.  A  few  brass,  round- 
head screws  and  a  wooden  base  make  up 
the  rest. 

Contributed  by    A.  C.  HANSEN,  JR. 


THE   ELECTRICAL   EXPERIMENTER  September,  1917 


332 

HOW    TO    CALCULATE  THE 
CANDLEPOWER  OF  A  LIGHT. 

To  compare  the  (illuminating)  power  of 
two  lights,  e.  g.,  lamp  (L)  and  candle  (C) 
is  quite  a  simple  matter  by  the  following 
(Rumford  or  shadow)  method:  Pin  to  the 
wall  a  piece  of  white  paper.  About  a  foot 
away  from  and  in  front  of  this  paper  fix 
a  rod,  R  (say  an  office  ruler),  vertically, 
says  a  writer  in  The  Amateur  Photogra- 
pher's Weekly.    Place  the  lamp  L,  in  line 


lamp  shadow 


A   Simple   Method   of   Determining  Candle- 
Power  of  a  Light. 


with  the  rod  so  that  it  casts  a  shadow  of 
the  rod,  R,  vertically  somewhere  about  the 
middle  of  the  paper  screen.  Now  place  the 
candle,  C  somewhere  between  L  and  R, 
so  that  the  two  shadows  of  R  cast  by  C 
and  L  are  just  touching  (side  by  side). 
Move  C  and  L  about  until  these  two 
shadows  seem  to  be  equally  dark — or  light, 
as  you  may  be  disposed  to  regard  mat- 
ters. Now  the  shadow  cast  by  L  is  il- 
luminated by  C,  and  that  cast  by  C  is 
illuminated  by  L.  The  illumination  values 
are  inversely  as  the  squares  of  their  dis- 
tances from  the  screen.  For  example,  sup- 
pose C  is  24  inches  from  the  screen  and 
L  is  84  inches  from  the  screen.  We  see 
at  once  that  dividing  these  distances  by  12 
we  get  2  and  7.,:  Squaring  these  numbers, 
we  have  4  ahd-'49,  roughly  say  4  and  50, 
i.  e.,  2  and  25,  or  1  and  12J4.  So  that  the 
lamplight  is  12^  times  the  light  or  candle- 
power  of  that  particular  candle.  For  more 
precise  results  you  must  obtain  a  stand- 
ard candle  (cost  about  25  cents). 


FUSE  CLIP  CLEANER. 

This  is  a  device  for  cleaning  fuse  clips 
on  blocks  using  cartridge  fuses  of  the 
ferrule  type,  and  as  dirty  clips  do  not  make 
good  contact  it  will  prove  a  very  useful 
and  handy  article  to  have.  It  is  made  from 
a  blown  fuse  of  the  proper  size  to  fit  the 
block  to  be  cleaned.  Take  two  pieces  of 
fine  emery  cloth,  cut  to  the  width  of  the 
brass  ferrules  of  the  fuse,  marked  A-A, 
and  just  long  enough  to  go  around  once. 
Put  a  little  glue  on  the  cloth  side  and 
squeeze  tightly  around  ferrule  and  tie  with 
a  string  to  hold  them  securely  until  the 
glue  has  had  time  to  dry.  Then  drill  a 
hole  thru  the  fiber  body  B,  and  insert  an 
eight-penny  nail  to  be  used  as  a  lever.  To 
use,  insert  in  the  fuse  clips  as  you  would 
an  ordinary  fuse  and  by  using  the  nail  as 
a  lever  and  rocking  it  back  and  forth,  you 
will  find  that  the  clips  have  been  evenly 


:  i  b 

 I  @_ 

Pull    This    Home-made    Cleaner    Back  and 
Forth  a  Few  Times  in  the  Fuse  Clips  and 
They  Will   Be  Thoroly  Cleaned. 

cleaned,  and  will  make  a  first-class  con- 
tact. A  large  percentage  of  fuses  are 
blown,  or  in  other  words  melted,  by  the 
heat  generated  from  a  poor  contact  of  the 
fuse,  and  the  fuse  terminals  or  clips. 
Contributed  by        FRED  R.  KLINK. 


"RADIO"  COMMUNICATION  OVER 
GAS  AND  WATER  PIPES. 

{Continued  from  page  318) 
Considering  the  receiving  apparatus 
necessary  to  pick  up  the  buzzer  signals  as 
transmitted  thru  the  earth,  we  have  at  Fig. 
1  the  simplest  type  of  receiver,  viz.,  one 
employing  a  radio  detector  such  as  silicon, 
or  other  mineral,  and  a  pair  of  radio  re- 
ceivers connected  unilaterally  to  the  water 
pipe.  We  call  particular  attention  to  this 
first  circuit,  as  it  shows  a  very  important 
consideration ;  i.  e.,  that  the  radio  detector 
circuit  of  whatever  type  used  should  be 
connected  only  in  a  unilateral  manner  so 
as  to  be  excited  by  one  wire  or  unipolar 
current.  The  detector  circuit  should  not 
under  any  condition  be  connected  in 
a  bipolar  manner,  or  the  operator  there- 
of is  liable  to  get  into  serious  trouble 
with  the  Government  authorities.  The  re- 
ceiving circuit  Fig.  2,  shows  a  unilateral 
detector  with  small  fixt  condenser  shunted 
across  the  'phones ;  this  local  circuit  be- 
ing tunable  by  means  of  a  loose  coupler, 
and  variable  condensers  shown.  The  pri- 
mary of  the  loose  coupler  is  connected 
thru  a  variable  capacity  to  the  water  and 
gas  pipes. 

The  receiving  circuit  shown  in  Fig.  3  is 
similar  to  diagram  No.  2,  except  that  an 
ordinary  tuning  coil  or  adjustable  aircore 
inductance  is  employed  instead  of  a  loose 
coupled  two-coil  transformer.  In  this  cir- 
cuit a  variable  condenser  may  be  used  as 
indicated  by  the  dotted  lines  to  properly 
attune  the  secondary  circuit.  Receiving 
diagram  No.  4  is  for  loose  coupler  and 
an  Audion  detector  which  is  connected  un- 
ilaterally. 

Several  hook-ups  are  given  for  combined 
transmitting  and  receiving  circuits  utilizing 
a  buzzer  transmitter  and  unilateral  radio 
receptor.  These  circuits  are  simple  and 
no  trouble  will  be  experienced  in  under- 
standing them. 

Diagram  No.  1  utilizes  a  double-contact 
telegraph  key;  diagram  No.  2  calls  for  a 
single  contact  key,  and  circuit  No.  3  also 
utilizes  a  single  contact  key,  but  requires 
a  two-point  switch  to  change  the  apparatus 
from  transmitting  to  receiving. 


A     HOME-MADE     ARC  SEARCH- 
LIGHT FOR  THE  AMATEUR. 

{Continued  from  page  329) 
rows,  from  one  end  to  the  other.   A  porce- 
lain tube  is  put  in  each  end. 

The  apparatus  is  connected  as  shown  in 
Fig.  5.  Two  lamp  cord  wires  are  run  from 
the  plug  and  socket  attachment  into  the  re- 
sistance box  and  connected  to  the  two  re- 
sistance wires,  one  to  each  row.  Lamp 
cord  connections  are  made  to  the  wires 
at  the  other  end  and  led  out  to  the  search- 
light. Here  they  run  thru  a  porcelain  tube 
into  the  searchlight,  where  they  are  con- 
nected to  the  screws  that  hold  the  carbons 
in  place.  Before  trying  the  searchlight 
change  the  fuses  in  its  circuit  to  at  least  15 
amperes.  This  is  important,  for  if  the 
searchlight  is  left  burning  continuously  very 
long,  fuses  of  lower  ampereage  are  apt  to 
blow.  To  use  the  searchlight,  push  in  the 
handle  with  the  rubber  knob  on  it  until  the 
carbons  touch.  The  light  will  not  be  very 
bright  until  the  ends  of  the  carbons  have 
points  burnt  on  them.  It  is  a  good  plan 
to  file  a  point  on  the  carbons  before  put- 
ting them  in.  Different  focuses  can  be 
obtained  by  merely  turning  the  knob  to  the 
right  or  to  the  left.  A  large  spot  is  best 
for  short  distances,  while  a  small  spot  is 
best  for  long  distances. 

I  have  shown  many  boys  in  my  home 
town  how  to  construct  searchlights  similar 
to  this  one.  A  searchlight  seems  to  inter- 
est every  boy. 


SELENIUM  CELL  DESIGN  AND 
CONSTRUCTION. 

{Continued  from  page  325) 
for  winding,  but  it  is  rather  difficult  to 
wind  such  wires  evenly. 

Another  modified  form  of  this  cell  con- 
struction is  shown  in  Fig.  3.  In  this  case 
the  selenium  is  placed  on  the  insulating 
support  before  the  wires  are  wound  on. 
This  form  was  not  found  to  be  very  sat- 
isfactory. It  is  difficult  to  properly  anneal 
as  the  selenium  is  practically  hidden  by 
the  wire  and  in  use  the  selenium  is  shaded 
too  much  by  the  wires  unless  the  light  is 
traveling  perpendicularly  to  the  axis  of  the 
cell  and  the  source  at  a  fairly  great  dis- 
tance. 

The  disadvantages  of  the  Bidwell  cell  are 
to  a  large  extent  done  away  with  in  the 
forms  of  construction  employed  by  Bell 
and  Taintor,  Mercadier  and  Fritts.  A 
cross-section  of  the  cell  employed  by  Bell 
and  Taintor  in  experiments  with  their  pho- 
tophone  is  given  in  Fig.  4.  Round  disks 
of  brass  or  copper  about  one  inch  in  di- 
ameter are  mounted  on  two  metallic  rods, 
the  plates  being  separated  by  mica  washers 
and  alternate  disks  connected  to  the  rods. 
The  result  is  a  cylinder  with  alternate 
plates  connected  to  the  same  terminal. 
The  selenium  is  flowed  over  the  surface 
of  the  cylinder  in  a  thin  layer  and  thoroly 
and  slowly  annealed.  This  construction  is 
good  where  it  is  feasible  to  use  a  para- 
bolic reflector,  so  all  sides  of  cell  may 
be  acted  upon.  The  thinner  the  film  on  the 
cell  the  greater  the  ratio  of  the  lighted 
to  the  darkened  resistance. 

Where  a  flat  cell  is  preferred  the  Mer- 
cadier type  will  be  found  useful.  In  this 
cell  the  conductors  are  wound  in  a  flat 
spiral  as  shown  in  Fig.  5.  Mica  strips 
serve  to  insulate  the  plates.  With  a  little 
care  excellent  cells  of  this  type  may  be 
constructed.  They  have  the  same  charac- 
teristics as  the  Bell  type  of  cell,  but  are 
of  simpler  construction.  Due  to  the  fact 
that  the  strips  are  curved,  it  will  be  found 
rather  difficult  to  make  a  number  of  these 
cells  having  the  same  resistance,  because 
slight  variations  of  the  curvature  between 
the  metallic  strips  will  result  in  cells  of 
widely  differing  resistance. 

To  Ruhmer  is  due  the  credit  for  en- 
closing selenium  cells  in  a  vacuum  to  pro- 
tect them  from  moisture  and  dust.  In  all 
types  of  cells  in  which  the  selenium  comes 
in  contact  with  the  air  it  is  advisable  to 
make  some  provision  to  keep  out  mois- 
ture. This  can  be  done  by  enclosing  in  a 
glass  bulb  or  test  tube.  Flat  cells  may  be 
enclosed  in  small  wooden  pill  boxes  which 
have  a  small  glass  window  on  one  side. 
A  simple  construction  employed  by  the 
writer  is  to  utilize  the  end  of  a  tubular 
flashlight.  The  tube  was  cut  off  just  back 
of  the  threaded  end  supporting  lens  and 
a  fiber  bottom  put  in.  The  container  was 
warmed  and  after  inserting  the  cell  was 
sealed  with  wax.  A  small  threaded  screw 
was  fastened  in  the  fiber  bottom  to  clamp 
the  cell  in  any  desired  position.  Another 
method  of  protecting  the  cells  is  to  paint 
them  with  a  transparent  varnish.  By  mix- 
ing dyes  with  this  varnish  it  is  possible 
to  make  a  cell  that  will  only  be  acted 
upon  by  one  color.  The  transparent  col- 
lors  sold  for  painting  postcards  will  be 
found  suitable  for  the  purpose. 

The  last  mentioned  cell,  the  Fritts,  is 
possibly  the  most  sensitive  type  ever  de- 
veloped. Its  construction  is  fairly  easy, 
but  gold  foil  is  used  in  the  construction. 
It  is  not  affected  to  an  appreciable  extent 
by  moisture  and  can  be  made  in  extremely 
small  sizes  without  difficulty.    (See  Fig.  6.) 

It  consists  essentially  of  a  thin  film  of 
selenium  on  one  side  of  which  is  a  copper 
{Continued  on  page  356) 


September,  1917 


THE  ELECTRICAL  EXPERIMENTER 


333 


Experimental  Chemistry 


Sulfuric  Acid  (History) 

SULFURIC  acid,  is  without  doubt,  the 
most  important  and  useful  acid 
known,  and  has  been  called,  next  to 
human  food,  the  most  valuable  of 
products.  By  its  means  nearly  all 
the  other  acids  are  prepared,  whilst  its 
manufacture  constitutes  one  of  the  most 
important  branches  of  modern  industry 
owing  to  the  great  variety  of  purposes  for 
which  it  is  needed,  as  there  is  scarcely  an 
art  or  trade  in  which  in  some  form  or  other 
it  is  not  employed.    In  enormous  quantities 


By  ALBERT  W.  WILSDON 

Sixteenth  Lesson 

acid,  and  from  its  property  of  fuming  in  the 
air  is  known  as  "Fuming  Sulfuric  acid." 

The  method  by  which  the  greater  part  of 
the  acid   is  at  present  produced   is  said 


and  Saltpeter  was  then  thrown  into  this 
ladle,  and  the  vessel  closed  in  order  to 
prevent  the  escape  of  the  vapors  which 
were  evolved.  These  vapors  were  absorbed 
by  the  water,  and  thus  Sulfuric  acid  was 
formed.  This  product,  from  the  mode  of 
its  manufacture,  was  termed  Oil  of  Vitriol. 

Preparation 

It  is  not  practical  to  make  the  acid  from 
its  salts.  Sulfur  dioxid  [S02]  in  presence 
of  water  [HaO]  and  some  oxidizer  becomes 
Sulfuric    acid    [H2SO4].     Sulfur  Dioxid 


Thistle  tube, 


Fig.    81.      Introducing    Burning    Sulfur  In 
Bottle  for  the  Minute  Preparation  of  Sulfuric 
Acid — H2S04. 


it  is  used  in  the  preparation  of  material  for 
bringing  food  plants  to  maturity,  in  the 
manufacture  from  common  salt  of  a  great 
variety  of  compounds  of  Sodium  and 
Chlorin,  which  enters  into  the 
making  of  such  commercial 
substances  as  glass,  soap, 
bleaching  powder,  and  even 
bread.  Scarcely  any  of  the 
products  of  civilized  life  have 
been  brought  to  perfection 
without  its  use,  directly  or  in- 
directly. It  is  manufactured  on 
an  enormous  scale  in  many 
countries;  nearly  one  million 
tons  are  annually  made  in  the 
United  States,  while  Germany 
had,  previous  to  the  European 
conflict,  produced  a  similar 
amount.  Great  Britain  pro- 
duced close  to  one  and  a  half 
million  tons. 

Geber  probably  made  and 
used  this  acid,  which  he  called 
"Vitriolic  Acid,"  but  Basil  Val- 
entine was  the  first  to  fully  de- 
scribe the  preparation  of  this 
acid  from  Ferrous  Sulfate 
[Fe  SO4]  or  Green  Vitriol,  and 
to  explain  that  when  Sulfur  is 
burnt  with  Saltpeter  a  peculiar 
acid  is  formed. 

Sulfuric  acid  was  originally 
obtained  exclusively  by  heating 
Green  Vitriol;  the  acid  thus 
prepared  consisted  of  Sulfur 
tri-oxid  dissolved  in  Sulfuric 


Fig.  82.  Method  of  Introducing  HNOa  on 
Paper  In  Bottle  In  Which  Sulfur  Was 
Burned.     For  Preparation  of  Sulfuric  Acid. 


to  have  been  introduced  into  England  from 
the  Continent  by  Cornelius  Drebbel ;  but 
the  first  positive  information  which  we  pos- 
sess on  the  subject  is  that  a  patent  for  the 
manufacture  of  Sulfuric  acid  was  granted 
to  a  quack  doctor  by  the  name  of  Ward. 
For  this  manufacture  he  employed  glass 
globes  of  about  40  to  50  gallons  capacity; 
a  small  quantity  of  water  having  been 
poured  into  the  globe,  a  stoneware  pot  then 
introduced,  and  on  to  this  a  red-hot  iron 
ladle  was  placed.    A  mixture  of  Sulfur 


Fig.  SO 


Set-up  of  Apparatus  Used  in  the  Laboratory  Preparation  of  Sulfuric 
Acid.  The  Apparatus  Follows:  A,  Flask  Holding  Water;  B,  Flask  Con- 
taining Copper  and  Sulfuric  Acid;  C,  Flask  Containing  Copper  and 
Nitric  Acid;  D,  Central  Flask,  the  Sulfuric  Acid  Generator;  E,  Tube 
for  Blowing  in  Air;  F,  Ventilator  Tube  (Side  Neck  Tube  In  Experiment 
Described);  G,  5-hole  Rubber  Stopper. 


Fig.  83.    Recording  on  Chemical  Thermom- 
eter  the   Temperature   Caused    by  Adding 
Sulfuric  Acid  to  Water. 

[SO2]  and  Water  [H20]  have  affinity  for 
each  other  and  form  Sulfurous  Acid 
[H2SO3],  which  only  requires  one  more 
Oxygen  atom  per  molecule  to  make  it 
Sulfuric  acid  [H,SO.].  If 
Oxygen  [O]  were  forced  thru 
the  Sulfurous  acid  [HiSOt],  or 
if  the  latter  were  exposed  to 
air,  a  weak  acid  would  very 
slowly  form,  but  in  practise  a 
stronger  oxidizer  is  needed. 
Nitric  acid  [HNO«],  Nitrogen 
Trioxid  [N2Os]  and  Nitrogen 
Peroxid  [N02]  are  most  ef- 
fectual for  this  purpose.  Sul- 
fur Dioxid  is  made  by  the  re- 
ducing action  of  Copper  [Cu] 
on  Sulfuric  Acid  [H,SOJ. 

Cu   +   2HSS04  = 
Copper  Sulfuric 
Acid 

CuSO«  +  2HaO  +  SO, 
Copper  Water  Sulfur 
Sulfate  Dioxid 

By  the  action  of  Copper  [Cu] 
on  Nitric  Acid  [HNOa],  Nitric 
Oxid  [NO]  is  formed,  and  in 
the  presence  of  air  oxidizes  to 
Nitrogen  Peroxid  [NOj]. 

3Cu  +  8HNO3  = 
Copper  Nitric 
Acid 

3Cu[NOa]3  +  4H20  +  2NO 
Copper  Water  Nitric 

Nitrat  Oxid 
Acid  Peroxid 
NO       +       O       =  NOs 
Nitric         Oxygen  Nitrogen 

(Continued  on  page  351) 


© 


334 


THE  ELECTRICAL  EXPERIMENTER 


September,  1917 


Wrf  inkles 

jfOfi.  ri«*r© 


o  , 

€?H  miliars 


EDITED  BY  S.GERNSBACK 


Under  this  heading  we  publish  every  month 
useful  information  in  Mechanics,  Electricity 
and  Chemistry.  We  shall  be  pleased,  of 
course,  to  have  our  readers  send  us  any 
recipes,  formulas,  wrinkles,  new  ideas,  etc.t 
useful  to  the  experimenter,  which  will  be 
duly  paid  for,  upon  publication,  if  acceptable. 


COMPOSITION  OF  ALLOYS. 

The  number  of  alloy  compositions  such 
as  bronze,  brass  and  babbitts  which  are 
now  placed  on  the  market  by  various  com- 
panies are  almost  innumerable,  each  con- 
taining various  proportions,  and  some  hav- 
ing special  ingredients  but  nearly  all  con- 
tain practically  the  same  combination  as  a 
basis.  In  almost  every  case  the  composi- 
tion is  varied  slightly  according  to  the  uses 
to  which  the  part  cast  from  the  alloy  is  to 
be  put. 

In  general  the  composition  of  the  most 
common  alloys  is  as  given  in  the  accom- 
panying table : 

Table  of  Composition  of  Common  Alloys 


Alloys 


u.          o  -s 

<U                 P  3 

H    U    N    <  kJ  pq 

1  .. 


1 


Babbitt's  metal...    10  1 

Bell-Metal    5    16  .. 

Brass,  engine  bear- 
ing   13  112  % 

Brass,  locomotive 
bearings    7    64  1 

Brass,   for  straps 
and  glands   16  130  1 

Flanges    to  stand 
brazing    32  1 

Muntz's  sheathing    . .      6  4   

Metal    to  expand 

in  cooling   2     9  1 

Pewter    100    ..    ..    17    ..  .. 

Spelter    1  1   

Statuary  Bronze..      2    90     5    ..      2  .. 

Tough   brass,  en- 
gine  work   15  100  15   

Tough   brass,  for 
heavy  bearings . .    25  160  5   

Yellow  Brass,  for 

turning    2  1   

Solders 

For  brazing  (hard- 
est)  3  1   

Forbrazing  (hard)     ..      1  1   

For  brazing  (soft)      14  3   

For  brazing  (soft) 

or    2    ..     ..      1    ..  .. 

For  lead    1    ..    ....  1^4  .. 

For  pewter    2    1 

For  tin    1    2 


EXPERIMENT  HOW  TO  MAKE  GAS. 

Take  some  hard  coal  and  grind  it  up 
fine.  Put  it  in  the  bowl  of  a  clay  pipe  and 
put  some  plaster  of  Paris  over  the  top  to 
seal  it.  Then  put  the  bowl  of  the  pipe 
over  or  in  the  flame  of  the  gas  stove.  In 
a  few  moments  the  gas  will  be  coming 
out  of  the  stem  of  the  pipe  and  the  same 
can  be  lighted. 

Contributed  by   SHERMAN  B.  LAW. 


AN  ELECTRIC  GAS  LIGHTER  FOR 
THE  "LAB." 

An  electric  gas  lighter  is  not  only  a  ne- 
cessity but  a  convenience,  especially  in 
laboratories  and  such  places,  where  gas  is 
turned  on  and  off  at  frequent  intervals. 
The  sketch  shows  how  the  writer  con- 
structed one  with  a  few  tools  and  in  a 
very  short  length  of  time.  The  casing  (F) 
is  of  hard  rubber  or  fiber  sawed  as  shown 
in  sketch;  the  bushings  (E)  and  (E')  are 
also  hard  rubber  or  fiber,  but  can  be  made 
of  impregnated  hard  wood.  Spring  (C) 
is  to  keep  the  movable  electrode  separated 
from  the  stationary  electrode  (A)  ;  (D)  is 
a  clamp  around  the  movable  electrode  to 
hold  the  spring  in  its  proper  place. 


A.C.l/ne 


i 

Inductance 


This  Electric  Gas  Lighter  Will  Be  Found  a 
Distinct  Convenience  in  Every  Shop  and 
Laboratory.  Use  an  Iron  Core  Inductance 
On  A.C.  Circuits  and  a  Resistance  Coil.  On 
D.C.  Circuits. 


The  wires  leading  to  the  line  and  in- 
ductance are  flexible  cords  and  may  be 
brought  out  to  small  terminals  on  the  side 
of  the  casing. 

The  inductance  can  be  varied  by  the 
number  or  turns  required  for  different 
cycles ;  the  inductance  used  by  the  writer 
was  obtained  from  an  old  A.  C.  arc  light 
but  one  may  be  easily  constructed  by  wind- 
ing a  number  of  turns  of  wire  around  a 
soft  iron  core. 

Contributed  by  HARRY  E.  BEANE. 


AN  IMPROVED  PIPETTE. 

In  chemical  laboratories  the  most  com- 
monly used  dropper  consists  of  a  straight 
glass  tube.  However,  if  the  tube  or  one's 
hands  are  wet,  the  dropper  is  hard  to  hold. 


57 


Dropper  m/n  loop  as  on  aid  for  ho/d/og  @ 


Place  Your  Finger  In  the  Loop  of  This  Im- 
proved Pipette  and  It  Simply  Can't  Slip  from 
Your  Grasp. 

I  overcame  this  difficulty  by  bending  the 
tube  so  as  to  form  a  complete  loop  in  it,  of 
about  three-fourths  of  an  inch.    One  can 


slip  a  finger  thru  this  loop  and  all  danger 
of  its  slipping  is  eliminated.  The  sketch 
represents  the  improved  dropper  more 
clearly. 

Contributed  by 

ALFRED  H.  HANSRATH,  JR. 


HOW  TO  SOLDER  ALUMINUM. 

There  are  various  compounds  on  the 
market  for  soldering  aluminum,  but  this 
operation  depends  more  on  the  workman 
than  on  the  solder  and  unless  considerable 
experience  has  been  had  it  is  probably  bet- 
ter to  purchase  solder  than  to  attempt  mak- 
ing it.  Zinc  can  be  used  but  does  not  form 
a  very  strong  joint.  Tin  can  also  be  used, 
is  more  nearly  the  color  of  aluminum,  is 
stronger  than  zinc,  but  is  very  difficult  to 
work.  A  small  proportion  of  phosphor  tin 
added  to  pure  tin  makes  it  work  more 
readily  and  is  the  basis  of  most  aluminum 
solder. 

The  chief  difficulty  in  soldering  alumi- 
num is  that  the  heat  is  dissipated  so  rapid- 
ly that  it  cools  the  soldering  iron  and  fur- 
thermore aluminum  oxidizes  instantly  upon 
exposure  to  the  air.  This  extremely  thin 
film  effectually  prevents  a  perfect  union 
being  made.  If  the  parts  are  well  heated 
and  melted  solder  kept  hot  while  the  iron 
is  allowed  to  stand  on  it,  the  surface  can 
be  scraped  beneath  the  melted  solder  by 
the  point  of  the  soldering  iron,  thus  pre- 
venting to  a  certain  extent  the  oxidization. 
In  this  way  the  metal  can  be  tinned.  When 
both  parts  to  be  brought  together  are  well 
tinned,  the  parts  can  be  united  with  some 
chance  of  success,  nitrat  of  silver,  resin,  or 
zinc  chlorid  being  used  as  a  flux.  A  solder- 
ing tool  of  nickel  gives  more  satisfactory 
results  than  a  copper  one  as  the  latter 
alloys  with  the  tin  and  soon  becomes  rough. 

Cleaning  the  Metal:  If  the  surface  is 
of  such  a  shape  that  it  cannot  be  readily 
cleaned  by  scraping,  it  can  be  cleaned  by 
dipping  it  into  a  solution  of  nitric  acid  in 
three  times  its  bulk  of  hot  water  contain- 
ing about  5  per  cent,  of  commercial  hydro- 
fluoric acid.  This  causes  a  slight  action 
on  the  surface  of  the  metal  as  shown  by 
bubbles.  Rinse  the  metal  after  removing 
from  the  acid  bath  and  dry  in  hot  sawdust. 

Aluminum  Solder:  The  following  for- 
mula, in  the  hands  of  a  competent  man,  can 
be  used  to  unite  aluminum  or  aluminoid 
parts : 

Tin — 10  parts. 

Cadmium — 10  parts. 

Zinc — 10  parts. 

Lead — 1  part. 
The  parts  to  be  united  must  be  thoroly 
cleansed  and  allowed  to  stand  two  to  three 
hours  in  a  strong  solution  of  Hypo-Sulfate 
of  soda  before  being  operated  upon,  or 
cleaned  in  the  acid  bath  described  above. 
Contributed  by  AN  EXPERIMENTER. 


THE  WHEEL  GLASS-CUTTER. 

Many  experimenters  have  at  some  time 
or  other  occasion  to  cut  glass,  and  no 
doubt  most  of  them  use  the  wheel-cutters, 
which  are  soon  thrown  away  as  of  no  use. 
Perhaps  the  following  tip  will  be  of  ser- 
vice to  them.  I  had  occasion  to  cut  some 
glass  a  few  days  ago,  and  had  only  an 
old,  and,  as  I  thought,  worn-out  wheel 
to  do  it  with.  I .  tried  dipping  it  in  a 
drop  of  paraffin,  and  was  astonished  to 
find  that  it  cut  as  well  as  when  new.  I 
experimented  with  two  others  which  I  had 
discarded,  and  found  that  they  cut  equally 
well.  Turpentine  seems  to  answer  the 
same  purpose. 

This  may  be  a  welcome  tip  to  some  of 
your  readers;  it  was  certainly  a  new  ex- 
perience for  me. 


September,  1917 


THE  ELECTRICAL  EXPERIMENTER 


335 


Our  Amateur  Laboratory  Contest  is  open  to  all  readers,  whether 
of  the  apparatus.  To  increase  the  interest  of  this  department  we  make  it  a 
photos  preferred  to  light  toned  ones.  We  pay  each  month  $3.00  prize  for 
Address  the  Editor,  "With  the  Amateurs"  Dept. 


subscribers  or  not.  The  photos  are  judged  for  best  arrangement  and  efficiency 
rule  not  to  publish  photos  of  apparatus  unaccompanied  by  that  of  the  owner.  Dark 
the  best  photo.    Make  your  description  brief  and  use  only  one  side  of  the  sheet. 


I    IN  THE  LANGUAGE  OF  "BILLY  SUNDAY"— "WAKE  UP!  YOU  ELECTRICAL  'LAB'  SLACKERS!!!" 

|    •  "Slackers!"  'at's  what  we  said.    Why  in  the  name  of  Howling  Pete  is  it,  that  you  "Electrical"  and  converted  (?)  "Radio-  f 

bugs"  can't  get  some  real  American  spirit  in  your  craniums  and  start  something?  The  way  you  slack  around,  bemoaning' the  § 
free-for-all  radio  experimental  days,  one  would  think  "Uncle  Sam"  had  injected  a  sleep-walking  toxin  in  every  mother's  "  [ 

son  of  you.    Suffering  kilowatts,  shake  yourselves — "Bugs !"    What's  the  world  coming  to  when  not  one  "Bug"  out  of  800,-  I 

000  of  you  ohm,  volt  and  oscillation  chasers,  will  condescend  to  accept  $3  in  prize  money?!!    The  devil'll  get  you  sure  as  f 

guns ;  said  devil  being  We,  Us  &  Co.    Open  your  eyes,  read  Mr.  Hammer's  eloquent  sermon  on  this  all-important  topic  in  I 

this  issue;  likewise  the  Editor's.    Read  'em!    Preach  em!    Then  dare  to  sit  tight  and  howl  "There  ain't  no  young  'Ham-  I 

mers'  or  'Edisons'  no  more."    Rot !    We  don't  and  won't  believe  you.    Now  get  busy  and  to  help  awaken  the  future  Fara-  1 

days,  Hammers  and  Edisons  we  will  give,  besides  the  $3  prize  for  the  best  "Electrical  Lab."  photo,  5  (FIVE!!!)  additional  1 

prizes  of  a  year's  subscription  to  this  journal  and  a  copy  of  the  "Experimental  Electricity  Course."    Come  on,  you  sore-  [ 

headed  "Radio-bugs";  hit  the  trail;  "Experimental  Electricity"  is  King  now.    Redeem  yourselves  to-day,  before  it  is  too  late.  I 

Address  the  Editor  "With  the  Amateurs"  Prize  Contest.  1 


A  GROUP  OF  ALL-AMERICAN  AMATEUR  RADIO  STATIONS. 

Radio  Stations  of,  5 — K.  F.  Gray,  Easton,  Pa.  (Prize  Winner);  1— William  F.  Warden,  Jr.,  Mt.  Dora,  Fla.;  2— A.  E.  Facks,  Brooklyn,  N.  Y.; 
3—  Harold  Bennett,  Clarinda,  Iowa;  4 — J.  H.  Hamilton,  Philadelphia,  Pa.;  6— John  F.  Isenberg,  Altoona,  Pa.;  7— Edward  G.  Raser,  Trenton, 
N.  J.;  8 — Floyd  M.  Rush,  Salem,  Ore.;  9— Guy  L.  Tullis,  Oskaloosa,  Iowa;    10— Russell   C.   Cravens,   Angola,    Ind.;   11— S.   Webster  Piper, 

Hagerstown,  Md.;  12 — Lot  and  Hodge  Alexander,  Grove  City,  Pa. 


336 


THE  ELECTRICAL  EXPERIMENTER 


September,  1917 


Prize  Winners  in  "Radio  Problem"  Contest 


We  are  pleased  to  publish  herewith  sev- 
eral of  the  suggestions  we  have  received  as 
well  as  the  prize  winning  ideas  telling  what 
to  do  with  your  radio  apparatus  during  the 
war.  Several  thousand  suggestions  were 
received  from  all  parts  of  the  country,  but 
the  majority  of  them  covered  similar  topics 
to  those  discust  below. 

FIRST  PRIZE  $10.00. 

A    Non-Radio    Communication    Scheme  That 
Works 

I  am  quite  sure  that  the  following  little  experi- 
ment should  fulfil  the  desired  wants  of  my  fellow 


Radio  friends  whose  apparatus  is  now  on  the 
shelf. 

In  the  following  explanation  I  will  show  how 
"idle"  condensers,  keys,  receivers,  and  buzzers 
can  play  an  important  part  in  re-establishing  com- 
munication between  them.  While  the  distance  is 
limited,  there  should  be  np  trouble  in  communi- 
cating thruout  the  city.  I  have  successfully  used 
this  system  for  a  distance  of  nine  (9)  city  blocks. 
The  circuits  thus  far  used  do  not  permit  the  re- 
ception of  "Radio"  signals  and  thereby  evade 
the  now  strict  law  regarding  Radio  stations  being 
kept  closed.  This  is  by  no  means  a  "Radio" 
station  and  cannot  be  clast  as  such.  I  cannot 
emphasize  too  strongly  on  this  point  regarding 
the  fact  that  Radio  signals  cannot  be  heard  at 
all;  this,  of  course,  gives  us  the  desired  results: 
"Idle"  apparatus  put  back  into  use  and  com- 
munication re-established. 

I  hope  that  you  will  not  fail  to  consider  the 
importance  of  such  a  system  when  it  will  bring 
thousands  and  thousands  of  my  friends  back  into 
the  game  and  help  pass  these  dreary  days  when 
almost  any  amateur  would  offer  $5.00  to  hear 
CQ  again.  The  best  feature  of  this  system  is 
that  it  is  naturally  a  "break-in"  system.  If  my 
friend  who  lives  nine  blocks  away  is  sending  to 
me  and  if  I  have  QRM,  I  just  make  some  dots 
and  he  stops.  It  certainly  is  interesting  and  we 
are  communicating  every  day.  As  yet  we  have 
not  heard  a  single  Radio  signal  on  it.  Just 
previous  to  the  declaration  of  war  we  were  free 
from  interference  as  we  were  the  only  ones 
using  this  circuit  in  town  and  it  therefore  was 
easy  working — and  it  is  now,  until  we  get  some 
other  one  wised  up  to  this  circuit  and  he  starts 
to  butt  in.  As  we  have  not  had  any  experience 
with  interference  it  will  be  hard  to  state  what 
action  a  third  party  will  have  on  the  interference 
question;  should  he  interfere  schedules  will  have 
to  be  arranged. 

Again — by  inserting  inductance  or  detectors  in 
the  receiving  circuit  no  change  is  detected;  there- 
fore none  are  required. — EDW.  T.  JONES. 


SECOND  PRIZE  $5.00. 

Buzzer    Communiciation    via    the    Water  Pipe 

There  is  about  only  one  way  left  by  which  we 
can  communicate  without  wires  and  use  our  radio 


Wafer  P/pe 


"1 


Suzzer 
V 


Mooes 


Tronsm/ffer  K 


Phones 


3 

Sat 


T 


sets  (that  is  part  of  them)  and  not  be  clast  as 
"wireless"  and  that  is  to  employ  some  sort  of 
ground  system,  such  as  a  water  or  gas  pipe  or  two 
ground  plates. 

Another  "Radio-bug"  of  this  city  has  a  friend 
in  Toronto,  Can.,  who  reports  that  the  experiment- 
ers there  are  using  a  water  pipe  for  the  conductor, 
a  buzzer  for  transmitting,  and  an  Audion  in  the 
receiving  circuit.  They  are  covering  about  ten 
miles  with  this  system.  We  have  no  more  "dope" 
as  to  the  exact  hook-up  at  present.  The  accom- 
panying hook-ups  might  be  worth  trying. 

In  cities  where  the  amateurs  are  close  together 
there  could  be  relays;  if  the  range  is  short  this 
would  be  quite  a  bit  of  fun  and  keep  us  from 
getting  too  rusty. 

A  spark  coil  or  a  transformer  could  possibly 
be  used  to  take  the  place  of  the  buzzer  for  greater 
distances.— OLIN  M.  WARREN. 


How  to  Use  Your  Radio  Apparatus  for  Scientific 
Tests 

As  I  have  actually  used  my  wireless  apparatus 
with  success  as  follows,  other  experimenters  will 
find  these  uses  practicable  and  interesting.    As  the 


Sensjt/ve 
Pod/o  'p/tones 


/nst//ctea[  contact 

Jr^f  Buzzer 


directions  for  constructing  the  apparatus  can  be 
found  in  back  numbers  of  The  Electrical  Ex- 
perimenter, I  have  refrained  from  giving  con- 
struction data  here. 

If  you  have  a  high-priced  pair  of  head  'phones 
they  need  not  remain  idle,  for  they  can  be  used 
in  connection  with  a  Hughes  "Induction  Balance." 
With  such  a  "balance"  you  can  test  the  sensi- 
tiveness of  various  receivers,  determine  the  de- 
gree of  magnetism  in  all  metals,  test  the  hearing 
ability  of  your  friends  and  the  relative  frequency 
of  currents.  In  connection  with  this  instrument 
your  receiving  condensers,  both  fixt  and  variable, 
will  come  in  handy.  Your  buzzer  set  can  be  used 
in  frequency  tests. 

The  helix  or  oscillation  transformer  can  be  used 
to  advantage  in  the  operation  of  a  musical  arc 
or  speaking  arc.  Such  an  arc  light  is  a  source 
of  much  amusement  and  the  mystification  of  your 
friends. 

If  you  have  a  coherer  set  with  a  good  relay, 
you  can  easily  construct  a  selenium  cell  to  use 
with  the  relay.  With  such  a  cell  you  can  start 
a  motor  by  waving  your  hand,  or  make  an  "elec- 
tric dog,"  and  numerous  other  experiments.  An 
Audion  can  be  used  to  advantage  in  connection 
with  the  selenium  cell. 

Finally  boys  be  patriotic  and  run  a  nice  big 
American  flag  up  your  wireless  mast.  Show  your 
patriotism!— ROBERT  CHANDLER. 


Oudin  or  Tesla  Coil  from  Tuning  Coil  and  Helix 

Take  a  single  slide  tuning  coil  and  remove  the 
rod  and  slider.    Then  set  the  coil  inside  a  helix 


smg/esz/ae , 


Helix'  f/ff  j 


(see  Fig.  1)  and  by  connecting  up  as  shown  in 
Fig.  2  an  Oudin  coil  will  be  the  result. 

Burned  out  Audion  and  electric  bulbs  make  good 
giessler  tubes.  By  nailing  copper  plates  to  the 
kitchen  chair  a  valuable  "Sing  Sing  Death  Chair," 
to  mystify  the  spectators  will  be  added  to  your 
apparatus. 

When  father's  "weather  foot"  begins  to  itch 
and  makes  him  angry,  place  him  on  the  electric 
chair  (easily  said)  and  give  him  a  shock.  A  few 
such  shocks  will  cure  his  gout  and  put  him  in  a 
better  mood.  High  frequency  currents  are  recog- 
nized as  a  good  remedy  for  many  aches  and  nerve 
troubles. 

Trusting  that  the  reader's  imagination  will  help 
him  with  other  stunts,  I  bid  you  .  —  —  


-LEWIS  MOSKOWITZ. 


Exhibit  Amateur  Radio  Apparatus 

It  seems  to  me  that  about  the  best  use  to  which 
the  amateur  wireless  operator  might  put  his  appa- 


ratus during  the  war  would  be  to  install  it  in  the 
nearest  Signal  Corps  recruiting  station.  Its  more 
or  less  intricate  appearance  as  a  whole  undoubted- 
ly would  attract  attention  and  enlistments.  Fur- 
thermore, it  would  arouse  enthusiasm  for  wire- 
less on  the  part  of  the  fellows  too  young  to  fight; 
and,  at  the  conclusion  of  hostilities,  they  might  go 
in  for  wireless.  As  such  an  experiment  would 
undoubtedly  act  directly  for  the  good  of  the  na- 
tion, and,  ultimately,  for  the  good  of  wireless 
itself,  it  seems  to  me  that  this  is  about  the  best 
use  to  which  the  amateur  might  put  his  apparatus 
daring  the  war.— JAMES  R.  ALLEN  (9EU). 

Electric  Vegetable  Cultivator 

Thinking  it  my  duty  to  send  you  an  idea,  to 


i 


frequency coil 

ijf-'vV  ^  V  »  «  Vi  * 


answer  the  question  "What  can  I  do  with  my 
wireless  apparatus,"  every  amateur  ought  to  help 
solve  the  food  question  and  he  can  if  he  adds  a 
Tesla  coil  to  his  outfit  and  uses  his  apparatus 
as  an  "Electric  Vegetable  Cultivator"  or  else  an 
X-ray  outfit. 

If  he  makes  an  Electric  Vegetable  Cultivator, 
he  will  not  only  derive  pleasure  out  of  it,  but 
profit  also.— BRUNO  BONKOFSKY. 


Convert  Radio  to  Electrical  "Lab." 

Why  not  enlarge  your  wireless  station  and 
change  it  into  an  electrical  laboratory?  Almost 
every  amateur  has  on  hand  odd  electrical  ap- 
paratus, such  as  bells,  magnets,  motors,  dynamos 
and  the  like.  Such  apparatus  as  this  with  the  wire- 
less set  will  make  up  a  large  part  of  the  laboratory 
equipment  and,  aside  from  making  it  look  "elec- 
trical," will  find  a  practical  use.  Such  parts  of 
the  wireless  set  as  the  spark  coil  or  the  step-up 
transformer  will  be  of  special  value  in  performing 
Tesla  experiments  or  in  X-ray  work.  Likewise 
other  parts  will  find  uses  equally  as  practical. 
From  time  to  time  articles  in  The  Electrical 
Experimenter  will  be  of  great  value  to  the 
amateur  in  his  work  and  I  am  sure  many  of 
them  will  explain  the  uses  of  wireless  instruments 
in  the  laboratory. 

Money  spent  in  laboratory  apparatus  and  for 
electric  books  is  always  well  invested. 

May  the  wireless  enthusiasts  get  together  on 
electrical  laboratory  work,  thru  The  Electrical 
Experimenter  and  clubs  thruout  the  country,  as 
they  have  been  in  wireless  telegraphy. — FRANK 
M.  JACKSON. 


More  High  Frequency  Stunts 

Herewith  are  given  a  few  ideas  for  the  use  of 
radio  instruments  during  the  war. 

The  average  amateur  sending  set  is  an  almost 
complete  high  frequency  generator.  All  that  is 
necessary  is  to  insert  within  the  old  helix  or 
oscillation  transformer  primary  a  secondary  of 
fine  wire  on  a  cardboard  tube  of  suitable  length. 
The  result  is  a  high  frequency  coil  of  either  the 
Tesla  or  Oudin  type.    See  Fig.  1  for  connections. 

By  connecting  a  loose  coupler  primary  across 
the  break  of  a  buzzer  and  a  telephone  receiver 


to  the  secondary,  we  have  an  instrument  for  dem- 
onstrating electromagnetic  induction,  for  tuning 
and  coupling  to  some  extent  and  for  code  prac- 
tice as  well  as  for  measuring  purposes.  See 
Fig.  II. — JACOB  HALLER,  JR. 


Several  other  good  ideas  will  appear  in  the  Octo- 
ber Issue. 


September,  1917 


THE  ELECTRICAL  EXPERIMENTER 


337 


Laboratory  "  Contest "(?) 


TOO  bad.  Too  bad.  Here  we 
have  gone  and  advertised  for 
three  solid  months  that  we 
wanted  photos  from  "bugs",  ex- 
perimenters, et  al,  showing  their 
laboratories.  Uncle  Sam  says :  "Boys, 
Wireless  is  taboo,  just  now.  Nix  on  the 
ether  waves."  The  Experimenter  being  a 
patriotic  sort  of  a  chap,  promptly  seconds 
the  motion.  The  radio  amateurs  not  to  be 
outdone,  not  only  second  the  motion,  but 
triple  and  quadruple  it,  i.  e.,  they  fire  radio- 
station  photos  at  us  till  the  postman  stag- 
gers under  the  load. 

Question :  Why  when  wireless  is  for- 
bidden  do    we    get    twenty  radio-station 
photos  a  day,  where  before  the  war  we  re- 
ceived but  two  or  three? 
Verily,  verily,  the  ways 
of  human  nature  are 
strange. 

At  any  rate  this 
month  we  proudly  ex- 
hibit one  specimen. 
Yes  this  one  is  the  real 
stuff,  no  fake  about  it, 
honest.  And  what's 
more — hang  the  mod- 
esty stuff — it  shows 
your  editor  in  person. 
You  always  wanted  to 
know  what  kind  of  a 
mug  he  has,  didn't 
you?  Well  you've  had 
your  wish.  True,  the 
picture  is  not  a  very 
recent  one,  having  been 
taken  some  odd  19 
years  ago,  but  it's  the 
best  to  be  had,  of  those 
memorable  days.  If 
we  were  to  tell  you 
that  the  proud  young 
person  in  the  picture 
was  13  years  old  when 
it  was  taken,  you  could 
of  course  figure  out 
quickly  how  old  the 
"ancient  crab"  is  at 
present.  But  as  mod- 
esty forbids  such  state- 
ments we  will  not  in- 
dulge in  them. 

At  any  rate  your  young  hopeful  was  as 
big  a  "bug"  as  grow  nowadays.  Yep,  he 
was  some  "bug."  There  was  nothing  that 
was  not  represented  in  that  "lab"  of  his. 
Of  course,  wireless  was  not  as  yet  invented 
in  those  days,  but  telephones,  batteries,  mag- 
netos, spark  coils,  meters,  Tesla  coils, 
motors,  dynamos,  etc.,  all  were  here  in  a 
great  array.  And  believe  us,  fellow  bugs 
and  buglets,  we  had  some  fun.  There  was 
a  telephone  line  and  a  telegraph  line  to  our 
friend's  house  and  we  even  had  a  Bell 
Photophone,  made  with  a  crude  selenium 
cell,  and  a  telephone  receiver  of  antique 
vintage.  This,  as  you  probably  know  works 
by  talking  over  a  ray  of  light,  using  the  back 
of  a  vibrating  mirror  as  the  sender,  while 
the  selenium  cell,  telephone  and  battery 
form  the  receiving  station. 

With  this  apparatus  we  covered  about  200 
feet  at  first.  The  transmission  of  speech 
was  very  good  and  the  articulation  fine — if 
we  yelled  loud  enough.  We  might  add  that 
we  could  hear  just  as  well  without  the 
apparatus !  But,  as  real  dyed-in-the-wool 
experimenters,  we  did  not  give  up.  Rather 
finally  we  "obtained"  (censor  deleted  the 
mode  of  "obtaining"  it)  a  commercial  selen- 
ium cell,  and  with  this  we  actually  trans- 
mitted articulate  speech  over  a  light  ray 
about  Yi,  of  a  mile.  It  worked  real  well,  too, 
and  it  is  a  matter  of  constant  surprise  to  us 
that  present  day  "bugs"  don't  go  in  for 


this  sort  of  work.  It  certainly  is  a  whole 
lot  of  fun  to  talk  over  a  mere  ray  of  light. 

Next  came  another  sort  of  "wireless" 
phone.  This  was  an  earth  conductive  sys- 
tem* by  burying  a  set  of  metallic  plates, 
100  feet  apart  at  different  levels  in  the 
earth.  A  microphone  and  batteries  con- 
nected with  the  plates.  The  receiving  end 
consisted  of  a  set  of  similar  plates,  spaced 
equally  apart,  and  buried  at  different  levels, 
too.  A  simple  telephone  receiver  connected 
with  the  plates.  Speech  was  thus  actually 
transmitted  over  a  distance  of  one  mile,  and 
this  outfit  worked  for  a  long  time.  By  us- 
ing large  zinc  and  copper  plates,  this  system 
was  improved  in  1903  and  over  3  miles  were 
then  covered. 


"La-dies  an'  Gen- 
You  Behold  the  Ge 
Yes, 


tell-menn!  This  Way,  Please — and  Don't  Crowd  Too  Much.  Here 
■  nnu-ine  and  Only  Photo  in  Captivity  Portraying  Your  Editor's  Phizl 
La-dies,  the  "Ancient  Crab"  Was  Some  "Bug"  Once! 

But  your  young  hopeful's  main  and 
staple  vice  in  those  days  was  batteries. 
Without  fear  of  contradiction  we  make  the 
sweeping  assertion  that  he  spent  more  time 
and  money  on  batteries  than  any  other  boy, 
alive,  dead,  or  as  yet  to  be  born,  Thomas 
Reed  inclusive  ! !  Batteries,  ah  !  You  elu- 
sive, ever  perplexing  devils !  And  we  made 
every  one  ourselves,  no  "boughten"  ones 
for  us. 

Ah,  yes,  those  brave  Bunsen's !  Some 
batteries !  Strong  as  an  ox,  both  in  cur- 
rent and  smell !  But  we  fixt  the  fumes  al- 
right, you  bet.  How?  Simplicity  itself! 
On  top  of  the  vile-smelling  nitric  acid,  con- 
tained in  the  porous  cups,  we  poured  about 
one  inch  of  petroleum !  That  stopt  the 
fumes  almost  entirely  and  the  batteries  kept 
on  working  longer.  Ten  such  batteries 
each  about  12  inches  high,  could  light  a 
dozen  or  more  16  volt  8  CP.  old  time  car- 
bon lamps,  and  what's  more,  the  Bunsen's 
kept  doing  it  for  2-3  weeks  on  one  filling, 
feeding  the  lights  each  night.  And  the 
lamps  burned  remarkably  steady,  too.  Of 
course,  the  cleaning  and  filling  was  a  nasty, 
messy  job,  and  many  a  pair  of  shoes  and 
pants  were  ruined  by  the  strong  acids,  but 
in  the  pursuit  of  science,  we  stop  at  no 
such  commonplace  items  as  these ! 


Our  photo  shows  the  young  battery  "bug" 
surrounded  by  his  Bunsen's.  As  may  be 
noted,  they  gave  quite  a  spark  on  short- 
circuit.  Soon,  however,  we  gave  up  the 
vile-smelling  Bunsen's  and  we  then  ran  the 
whole  gamut  of  the  battery  will-o'the-wisp. 
Chromic-acid,  one  and  two  fluid ;  Daniel 
copper  sulfate;  Edison-Lalande  copper- 
oxid;  gravity  copper  sulfate  cells;  peroxid 
of  lead-zinc  (a  good  battery  by  the  way) 
down  to  Upman's  chlorin-gas  battery.  Yes, 
we  believe  there  is  no  battery  that  was  ever 
invented  that  we  did  not  actually  try  out. 
Some  day  we'll  describe  a  few  new  ones,  so 
as  not  to  be  humiliated  by  Tom  Reed ! 

At  any  rate  we  finally  settled  down  and 
compromised  on  an  8  cell  glass  jar  storage 
battery,  giving  16  volts 
and   40  ampere-hours. 
Each  of  these  8  cells 
were    connected    to  a 
"Pachytrop"  exactly 
described  by  Mr.  C.  A. 
Oldroyd  in  the  March, 
1917,  issue  of  this  jour- 
nal. Turning  the  handle 
90    degrees  connected 
all  the  cells  in  parallel. 
Another  turn  connected 
the    cells     in  series. 
While     connected  in 
parallel  the  eight  stor- 
age    cells     gave,  of 
course,  about  2  volts, 
and   in    this  position 
they  were  charged  by 
eight  very  large  copper- 
oxid-caustic  soda-zinc 
batteries.    These  cells 
are   ideal   for  storage 
battery   charging,  and 
will  be  described  fully 
in  a  later  issue,  if  we 
can  find  the  time.  Suf- 
fice it  to  say  that  each 
cell  was  made  of  black 
sheet  iron  in  the  form 
of    a    tray,    about  18 
inches  long  by  12  inches 
wide.    The  height  was 
but    3    inches.  These 
trays     were  copper- 
plated    inside   and    a    stout    copper  wire 
was  soldered  in  a  corner.    This  formed 
the  positive  pole.    The  bottom  of  the  tray 
was  covered  with  a  y2"  layer  of  Cupron 
nuggets,*  while  in  each  corner  of  the  tray 
there  was  a  small  porcelain  insulator.  On 
top  of  these  a  heavy  zinc  plate,  well  amal- 
gamated was  placed.    The  tray  was  then 
filled  with  a  solution  of  caustic  potash,  so 
that  it  stood  J/2"  over  the  zinc  plate.  On 
top  of  the  caustic  potash  we  poured  a  layer 
of  mineral  oil.   The  battery  was  then  ready 
to  operate  at  once,  and  it  gave  about  0.9 
volt  and  12  amperes.    This  voltage  dropt 
to  0.7  when  charging  the  storage  cells.  The 
eight  tray-batteries,  therefore,  gave  over  6 
volts,  enough  to  charge  the  storage  batteries. 

These  Cupron  cells  were  "all  to  the 
good"  and  gave  no  trouble  worth  mention- 
ing. They  did  not  mind  in  the  least  being 
short-circuited  for  hours  at  a  time,  and 
the  steadiness  of  the  current  is  amazing. 
These  batteries  are  perfectly  odorless,  re- 
quire no  attendance  and  need  not  be  filled 
for  months  at  a  time.  Nor  are  materials 
consumed  when  they  stand  idle. 

Now  "bugs,"  for  the  love  of  Pete,  get 
busy  and  shoot  along  those  "lab"  photos. 
We  aren't  paid  to  write  up  this  sort  of 
"dope."  Soon  we'll  strike !  Lookatatime ! 
1  A.  M. ! !  Have  you  no  pity  on  the  over- 
worked "old  man"  ? ! 


*  See  "The  Wireless  Telephone,"  by  H.  Gems- 
hack,  Page  26. 


*  Cupron  is  a  higher  form  of  the  ordinary  com- 
mercial   copper-oxid,    i.    e.,  suboxid. 


338 


THE  ELECTRICAL  EXPERIMENTER 


September,  1917 


LITEST  k^TENT5 


Magnetic  Battery  Gage 

(No.  1,231,708;  issued  to  Emerson 
L.  Clark.) 
A  simple  form  of  battery  gage 
especially  for  use  with  dry  cells. 
The  cost  of  the  device  is  very 
low,  and  it  is  extremely  simple  and 
rugged     in     design.       It  indicates 


whether  a  cell  is  up  to  standard 
by  means  of  an  audible  signal  or  by 
the  sense  of  touch.  A  low  resistance 
magnet  coil  is  wound  on  the  non- 
magnetic frame,  and  when  the  point 
of  the  instrument  is  placed  on  one 
battery  terminal,  and  the  flexible 
lead  touched  to  the  other  terminal, 
the  coil  will  produce  a  magnetic 
field,  thus  pulling  up  the  iron  arm- 
ature. This  can  be  heard  when 
attracted  by  the  magnet  core,  and 
if  the  finger  is  placed  over  the  top 
of  the  hollow  core,  the  rising  arma- 
ture pin  will  strike  the  finger,  giv- 
ing a  second  form  of  indication. 
The  inventor  gives  details  for  elabo- 
rating the  moving  armature  design 
so  as  to  use  scales;  thus  permitting 
of  calibrating  the  instrument  for 
any  strength  of  current. 


Metallic  Audion 

(No.    1,230,874;   issued   to   Lee  de 
Forest.) 

Dr.  de  Forest,  the  well-known 
radio  inventor,  has  here  developed 

Ond  and  fz/omenf 

4- 


t — T 

Metaf  floslt  tv/nge/ement 
an  especially  desirable  form  of 
Audion  blub,  which  is  made  of 
metal  so  as  to  stand  transportation 
better  than  glass.  Moreover,  the 
metal  flask  containing  the  grid  and 
filament  elements  serves  as  the  wing 
or  plate.  The  grid  support  is  pre- 
ferably all  glass,  and  the  patent 
contains  details  of  assembling  the 
flask  and  other  parts.  Finally  a 
metal  bottom  is  welded  to  the  open 
end  of  the  flask,  and  the  completely 
inclosed  receptacle  thus  formed  is 
connected  to  a  vacuum  pump,  and 
thereby  exhausted  of  air  thru  the 

usual  tip.   

Measuring  Gage  for  X-Rays 
(No.    1,229,740;    issued    to  Robert 
Furstenau.) 
This   invention    is   based    on  the 


Wheotsto.ne. 
Bridge 


K-ray  tube 


fact  that  crystalline  selenium  has 
the  property  of  varying  its  elec- 
trical resistance  when  subject  to 
the    action    of    X-rays.      This  re- 


sistance variation  is  very  slight  for 

X-rays,  but  the  patentee  overcomes 
this  objection  by  placing  the  seleni- 
um cell  in  one  branch  of  a  Wheat- 
stone  bridge  as  shown  in  the  dia- 
gram. The  arrangement  and  the 
strength  of  the  resistances  are  so 
calculated  that  when  the  selenium 
cell  is  not  exposed  to  any  rays,  a 
current  flows  thru  the  galvanometer 
of  the  bridge  in  a  direction  which 
is  opposite  to  that  of  the  current 
flowing  thru  the  instrument  when 
the    cell    is    exposed    to    the  rays. 


Electric    Steering    Wheel  Heater 

(No.   1,230,788;   issued  to   Even  J. 
Rohne.) 

If  you  have  had  occasion  to  drive 
a  motor  car  in  the  winter  time, 
you  will  most  probably  agree  with 


the  inventor  of  this  device  that  some 
simple  form  of  heater  for  the  steer- 
ing wheel  will  prove  a  very  wel- 
come addition  to  the  automobile 
world.  The  invention  here  shown 
comprises  a  long  flexible  ribbon 
made  of  leather,  cloth,  etc.,  folded 
upon  itself  to  form  a  flat  casing 
which  serves  to  support  and  insu- 
late the  electric  heating  elements 
or  wires,  and  which  elements  may 
be  connected  either  in  series  or  in 
multiple.  The  electric  heater  may 
be  connected  to  the  storage  battery 
or  dynamo  of  the  automobile,  and 
takes  but  little  current. 


Electric  Wave-Filter 

(No.    1,227,113;    issued    to    G.  A. 
Campbell.) 
This  patent  relates  to  an  electric 


Spark  Gap  Improvement 

(No.    1,231,489;    issued    to    C.  E. 
Campbell.) 
A  unique  design  of  spark  gap  in- 
tended particularly  for  high  power 


terial  such  as  bibulous  paper,  and 
then  bent  or  corrugated  as  shown 
in  a  sinuous  form.  The  zinc  is 
first  perforated  so  that  the  carbon 
cathode  can  pass  thru  the  various 
undulations  of  the  encased  zinc  ele- 
T  ment  without  touching  the  zinc  it- 
self. 


X-ray  equipment.  The  spark  gap 
shown  comprises  one  or  more  pair 
of  stationary  spark  electrodes,  each 
electrode  being  fitted  with  a  large 
number  of  cooling  vanes  in  the 
manner  shown.  Opposite  each  pair 
of  stationary  electrodes  there  is  pro- 
vided a  disc  electrode  threaded  on 
the  outer  perifery  and  arranged  by 
gears  or  otherwise  with  a  suitable 
adjusting  knob,  so  that  the  one  or 
more  discs  can  be  advanced  or  re- 
ceded from  the  stationary  electrodes; 
thus  varying  the  gap  length. 


Door-Knob  Flashlight 

(No.    1,230,942;    issued   to  August 
Sundh.) 

The  outermost  face  of  the  knob 
comprises  a  diafram  with  a  switch 
attachment,   and  when   deprest  this 


Ref/ecfor. 


lamp 


Baltery 


closes  the  lamp  circuit.  The  light 
is  reflected  by  means  of  a  lens  and 
two  distinct  reflectors  placed  at 
right  angles  to  the  axis  of  the  knob, 
thru  a  glass  container  and  between 
the  supporting  spider  of  the  knob  it- 
self. A  new  battery  may  readily 
be  replaced  by  unscrewing  the  outer 
diafram  switch  cap. 


Unique  Dry  Cell  Battery 

(No.  1,231,057;  issued  to  Herbert 
R.  Palmer.) 
Apparently  this  idea  presents  a 
marked  advance  in  battery  design. 
The  patentee  claims  to  have  in- 
creased the  life  of  a  given  size  of 
dry  cell  three  hundred  per  cent  over 
the  ordinary  type  of  the  same  size 
and   weight.     This  remarkable  effi- 


wave  filter  utilizing  a  multiplicity 
of  interconnected  and  specially  tuned 
circuits  comprising  inductance  and 
capacity  especially  adapted  to  trans- 
mit with  negligible  attenuation, 
sinusoidal  currents  of  all  frequen- 
cies lying  within  a  range  of  pre- 
assigned  limiting  frequencies,  while 
attenuating  and  extinguishing  sinu- 
soidal currents  of  frequencies  lying 
outside  the  limits  of  the  pre-assigned 
range.  This  wave  filter  is  applic- 
able to  wireless  telegraphy  and  tele- 
phony, multiplex  high  frequency 
wire  telephony,  etc.,  and  particular- 
ly for  use  on  telephone  repeater  cir- 
cuits. The  diagram  shows  two 
Audion  type  relays  connected  with 
the  wave-filter  circuits,  and  in  series 
with  a  telephone  line,  each  side  of  ckiio  'S  attained  by  employing  a 
the  line  being  connected  to  the  long,  undulating  strip  of  zinc,  which 
terminals  3  and  4.  is  thoroly  encased  in  a  porous  ma- 

COPIES  OF  ANY  OF  THE  ABOVE  PATENTS  SUPPLIED  AT  10  CENTS  EACH 


Electric  Disinfector  and 
Deodorizer 

(No.  1,230,342;  issued  to  R.  Thorn- 
berg.) 

An  ordinary  tubular  incandes- 
cent lamp  is  employed  as  the 
source  of  heat  for  vaporizing  the 
disinfecting  or  medicating  liquid, 
which  is  placed  within  the  glass 
bulb  in  the  manner  illustrated.  A 


perforated  tube  surrounds  the  lamp, 
the  tube  itself  being  covered  with 
an  absorbing  wick.  In  this  way 
the  liquid  is  spread  out  so  as  to 
realize  the  full  vaporizing  benefit 
from  the  heat  of  the  lamp,  and  the 
vapor  escapes  thru  the  perforated 
ring  at  the  top  of  the  device  as 
shown  by  the  arrows. 


Illuminated  Pencil 

(No.    1,230,721:    issued  to 
Kelly.) 


Gloss 
cap 


e.  v. 


Leod  tube 


Lamp— 


Switch- 


A  useful  invention  comprising  a 
suitable  casing  containing  a  minia- 
ture dry  cell,  small  tungsten  lamp, 
and  means  for  holding  the  pencil 
lead  as  well  as  a  switching  device. 
To  open  or  close  the  lamp  circuit, 
the  sliding  cap  at  the  end  of  the 
pencil  is  moved  into  or  out  of  con- 
tact with  the  lower  end  of  the  dry 
battery. 


September,  1917 


THE  ELECTRICAL  EXPERIMENTER 


339 


Under  this  heading  are  publisht  electrical  or  mechanical  ideas  which 
our  clever  inventors,  for  reasons  best  known  to  themselves,  have  as  yet 
not  patented.  We  furthermore  call  attention  to  our  celebrated  Phoney 
Patent  Offizz  for  the  relief  of  all  suffering  daffy  inventors  in  this  country 
as  well  as  for  the  entire  universe. 

We  are  revolutionizing  the  Patent  business  and  OFFER  YOU  THREE 
DOLLARS  ($3.00)  FOR  THE  BEST  PATENT.  If  you  take  your  Phoney 
Patent  to  Washington,  they  charge  you  $20.00  for  the  initial  fee  and  then 


Phoney  Patents 


you  haven't  a  smell  of  the  Patent  yet.  After  they  have  allowed  the  Pat- 
ent, you  must  pay  another  $20.00  as  a  final  fee.  That's  $40.00!  WE 
PAY  YOU  $3.00  and  grant  you  a  Phoney  Patent  in  the  bargain,  so  you 
save  $43.00!!  When  sending  in  your  Phoney  Patent  application, 
be  sure  that  it  is  as  daffy  as  a  lovesick  bat.  The  daffier,  the  better. 
Simple  sketches  and  a  short  description  will  help  our  staff  of  Phoney 
Patent  examiners  to  issue  a  Phoney  Patent  on  your  invention  in  a 
jiffy. 


PHONEY  PATENT  OFFIZZ 


FIRST  PRIZE :  Catextinqwisher.  Music  of  Feline  Cats  Impinges  Upon  Sensitive  Microphones  Near  Top  of  Fence.  These  Operate  Relay  Thru  Storage  Battery.  The  Latter  Operates 
Motor  Attached  to  Winding  Drum.  String  on  This  Winds  Up,  Closing  Scissors.  Scissors  Cut  String.  Brick  Drops  on  See-Saw  Board.  This  Rubs  Match  At  End  of  Board  on  Sand 
Paper.  Match  Lights  Fuse  of  Cannon,  Which  Goes  Off.  Bullet  Hits  Bessemer  Steel  Target  Which  Pulls  Lever,  Thus  Opening  Water  Supply.  Water  Stream  Extinguishes  Cats  and 
Music.  Inventor:   H.  Gehrig,  Cincinnati,  Ohio. 


COLTPOWER:  The  Prodlgous  Power  Let  Loose  by  Frisky  Colts  Has  Never  Been  Harnessed.  This  Pattent  Solves  the  Trick.  By  Attaching  Gears  and  Racks  to  the  Colt,  Every 
Time  He  Gets  Frisky  and  Kicks,  He  Generates  Electricity  Thru  the  Dynamo  Attached  to  His  Back.    Likewise  If  He  Feels  Like  Jumping  and  Running  About,  Steel  Cables  Attached 

to  His  Collar  Will  Operate  Certain  Spring  Drums,  Which  Latter  Thru  Pulleys  and  Gears  Work  the  Dynamo.    Thus  Lots  and  Oodles  of  Juice  Is  Generated.   

Inventor:    Paul  Cromwell.  Elklns,  W.  Va. 


340 


THE  ELECTRICAL  EXPERIMENTER 


September,  1917 


QUESTION  BOX 


This  department  is  for  the  sole  benefit  of  all  electrical  experimenters.  Questions  will  be  answered  here  for  the  benefit  of  all,  but  only 
matter  of  sufficient  interest  will  be  publisht.    Rules  under  which  questions  will  be  answered: 

1.  Only  three  questions  can  be  submitted  to  be  answered. 

2.  Only  one  side  of  sheet  to  be  written  on;  matter  must  be  typewritten  or  else  written  in  ink,  no  penciled  matter  considered. 

3.  Sketches,  diagrams,  etc.,  must  be  on  separate  sheets.  Questions  addrest  to  this  department  cannot  be  answered  by  mail  free  of  charge. 

4.  If  a  quick  answer  is  desired  by  mail,  a  nominal  charge  of  25  cents  is  made  for  each  question.  If  the  questions  entail  considerable  re- 
search work  or  intricate  calculations  a  special  rate  will  be  charged.  Correspondents  will  be  informed  as  to  the  fee  before  such  questions  are 
answered. 


KITE  ANTENNA. 

(825.)  Everett  Converse,  Ft.  Collins, 
Colo.,  writes  us : 

Q.  1.  Please  tell  me  if  No.  24  bare  cop- 
per wire  suspended  from  a  kite  would 
make  a  satisfactory  aerial  and  what  would 
be  its  wave  length,  if  400  feet  of  such  wire 
was  used? 

A.  1.  450  meters. 

Q.  2.  Would  this  No.  24  bare  copper 
wire  be  all  right  to  wind  a  tuning  coil  with 
and  what  would  be  good  for  insulation 
between  turns? 

A.  2.  Yes.  The  insulation  between  turns 
should  consist  of  a  silk  thread  impregnated 
with  shellac.  A  still  better  method  of  wind- 
ing this  wire  is  to  make  a  thread  on  the 
surface  of  the  tube  by  placing  it  on  a 
lathe  and  winding  the  wire  in  the  threads 
so  formed.  This  is  an  ideal  method  and 
all  commercial  coils  of  this  type  are  made 
in  this  manner. 


INDUCTION  MOTOR. 

(826.)  Paul  E.  Nelson,  Fort  Smith, 
Ark.,  wishes  to  know : 

Q.  1.  Can  a  two-phase,  220-volt,  60-cycle 
y2  H.P.  induction  motor  be  changed  to  run 
on  110-volt,  60-cycle  A.  C? 

A.  1.  Yes,  by  rewinding  the  stator  or 
field  coils  so  as  to  be  operated  on  110  volts. 

Q.  2.  About  how  much  power  would  be 
developed  ? 

A.  2.  The  power  developed  will  be  the 
same,  or  H.P.,  since  the  motor  will  now 
consume  twice  the  current  it  would  when 
operated  on  220  volts. 


SUBMARINE  COMPASS. 

(827.)  Cyril  Thorn,  St.  Louis,  Mo.,  in- 
quires : 

Q.  1.  I  would  like  to  know  how  a  sub- 
marine can  use  a  compass.  I  should  think 
that  the  steel  shell  of  the  submarine  would 
act  as  a  magnetic  screen  to  the  earth's 
lines  of  force.  Of  course,  I  mean  when 
they  are  submerged. 

A.  1.  Submarines  do  not  employ  a  mag- 
netic compass  but  they  use  a  gyroscopic 
compass  which  is  not  affected  by  magnetic 
bodies  but  by  the  earth's  rotating  forces. 
It  would  be  impossible  to  use  a  magnetic 
compass  on  a  submersible  due  to  the  mas- 
sive iron  hull  surrounding  the  compass, 
which  would  act  as  a  magnetic  screen  as 
you  mention. 


DETECTOGRAPH. 


w  re 5  phone 
s  ohms  1 


5uper  sens/hre 
m/crophone 


r 


Battery 


© 


Hook-Up    for    Sensitive   Telephone    Set  or 
"Detectograph." 

(828.)  Owen  Walker,  Lewiston,  Me., 
writes  us : 

Q.  1.  What  instruments  are  necessary 
for  me  to  build  a  detectograph? 


A.  1.  A  sensitive  microphone,  a  low  re- 
sistance telephone  receiver  and  a  flash- 
light battery. 

Q.  2.  Where  can  I  buy  them? 

A.  2.  You  can  purchase  these  parts  from 
the  Microphone-Detector  Co.,  26  Cortlandt 
St.,  New  York  City,  N.  Y. 

Q.  3.  Please  give  me  a  diagram  of  con- 
nections. 


ODD  PHOTOS  WANTED  AT 
$1.00  EACH! !  ! 

Now  is  the  time  to  make  your 
Kodak  pay  for  itself  in  a  real  practi- 
cal way.  We  are  after  interesting 
photographs  of  out-of-the-ordinary 
electrical,  radio  and  scientific  sub- 
jects and  are  willing  to  pay  $1.00  cash 
for  every  one  we  can  use.  Please 
bear  in  mind  that  for  half-tone  re- 
production in  a  magazine,  a  photo- 
graph should  be  particularly  sharp 
and  clear.  Of  course,  if  a  subject 
happens  to  interest  us  particularly 
well,  we  can  have  the  photo  retouched. 
For  the  general  run  of  subjects,  how- 
ever, it  does  not  pay  to  go  to  such 
expense.  Therefore,  please  take  pains 
to  properly  focus  and  expose  your 
pictures.  It  often  happens  that  a 
really  mediocre  subject  well  photo- 
graphed wins  approval  over  an  ex- 
cellent subject  poorly  photographed. 
And  don't  send  us  plate  or  film  "nega- 
tives";  send  unmounted  or  mounted 
"prints,"  preferably  a  light  and  a  dark 
one. 

As  to  what  to  photograph:  Well, 
that's  hard  for  us  to  say.  We  leave 
that  up  to  you,  and  every  reader  now 
has  the  opportunity  to  become  a  re- 
porter of  the  latest  things  in  the  realm 
of  Electricity,  Radio  and  Science. 
But,  please  remember — it's  the  "odd, 
novel  or  practical  stunts"  that  we  are 
interested  in.  Every  photo  submitted 
should  be  accompanied  by  a  brief  de- 
scription of  100  to  150  words.  Give 
the  "facts" — don't  worry  about  the 
style.  We'll  attend  to  that.  Enclose 
stamps  if  photos  are  to  be  returned 
and  place  a  piece  of  cardboard  in  the 
envelape^with  them  to  prevent  mutila-  ■ 
Hon.  Look  around  your  town  and 
see  what  you  can  find  that's  interest- 
ing. 

Address  photos  to — Editor  "Odd 
Photos,"  Electrical  Experimenter, 
233  Fulton  Street,  New  York  City. 


A.  3.  The  wiring  diagram  of  the  instru- 
ments is  given  herewith. 


ELECTROSTATIC  VOLTMETER. 

(829.)  Henry  Manville,  Los  Angeles, 
Cal.,  writes : 

Q.  1.  Kindly  describe  and  explain  the 
action  of  an  electrostatic  voltmeter  as  used 
in  the  measurement  of  high  tension  electro- 
motive forces. 


A.  1.  The  Kelvin  voltmeter,  developed 
by  Lord  Kelvin,  its  inventor,  is  suitable 
for  direct  or  alternating  currents  from  40 
to  100,000  volts.     A  certain  well-known 


Connection  and  Principal  Parts  of  Electro- 
static Voltmeter  Such  As  Used  In  Measuring 
High  Potentials. 

company  has  developed  a  line  of  electro- 
static voltmeters  for  pressures  from  2,500 
to  120,000  volts  using  condensers  in  series. 
In  the  diagram  a  and  ai  are  movable  con- 
denser elements  consisting  of  hollow  spher- 
ical members  supported  on  a  steel  ball 
bearing  mounted  on  polished  jewels;  b 
and  bi  are  covered  metallic  sheets  form- 
ing the  opposite  plates  of  condensers 
which  a  and  at  approach  as  they 
rotate ;  c  and  Ci  are  pairs  of  plates  of  con- 
densers in  series,  being  connected  on  one 
side  of  the  instrument  t  and  tj  and  on 
their  other  side  to  the  inner  condenser 
plates  b  and  bi.  The  rotation  of  a  and  ai 
is  opposed  by  controlling  springs,  the  posi- 
tion of  equilibrium  where  the  attraction 
between  the  fixt  plates  b  and  bi,  and  the- 
moving  cylinders  a  is  balanced  by  the 
springs ;  the  indication  is  given  by  a  pointer 
moving  along  the  scale  shown.  The  con- 
taining case  is  filled  with  oil  which  buoys 
up  the  moving  element,  acts  as  a  damper 
to  the  moving  system  besides  maintaining 
high  insulation  and  increasing  the  capacity. 


D'ARSONVAL  GALVANOMETER. 

(830.)  George  Whiting,  San  Francisco, 
Calif.,  asks : 

Q.  1.  What  is  the  size  of  wire  used  on 
the  winding  and  what  is  the  coil  suspended 
by,  a  flat  strip  or  a  wire,  on  a  D'Arsonval 
galvanometer  of  the  reflecting  mirror  type? 

A.  1.  The  size  of  wire  used  in  these  type 
of  galvanometers  depends  upon  the  degree 
sensitiveness  of  the  instrument,  but  in  gen- 
eral the  wire  used  on  the  coil  is  a  No.  38 
double  silk  covered  magnet  wire.  The  coil 
is  suspended  by  a  thin  strip  of  phosphor 
bronze. 

Q.  2.  What  is  the  resistance  of  80  feet 
of  No.  30  soft  iron  wire? 
A.  2.  34.8  ohms  resistance. 
Q.  3.  What  is  the  ratio  of  movement  on 


September,  1917 


THE  ELECTRICAL  EXPERIMENTER 


341 


C 

KEY  f> 


a  galvanometer  mirror  to  the  foot;  i.e., 
suppose  the  mirror  moved  .0001  of  an  inch, 
how  much  would  the  spot  of  light  from 
the  mirror  move  at  1  foot  distance  and  at 
8  feet  distance? 

A.  3.  It  would  be  impossible  for  us  to 
give  you  this  data  as  it  is  necessary  to 
know  the  angular  momentum  of  the  mov- 
ing element,  which  means  that  the  weight 
of  the  element  is  required  which  is  neces- 
sary to  determine  the  time  constant  of  the 
coil.  Furthermore,  it  will  be  necessary  for 
us  to  know  the  curvature  of  the  mirror, 
in  order  to  give  you  the  intensity  of  illumi- 
nation which  the  mirror  will  throw  at  the 
distance  specified. 


STORAGE  BATTERY  FOR  SIX- 
INCH  COIL. 

(831.)  Sidney  Tholan,  Washington, 
D.  C,  would  like  to  know : 

Q.  1.  How  many  storage  batteries  would 
a  six-inch  spark  coil  require,  or  how  many 
volts  and  amperes  would  it  require  to  give 
best  results,  with  an  aerial  50  feet  high  and 
75  feet  long,  consisting  of  four  wires? 
How  far  would  this  coil  transmit  in  a 
tuned  sending  outfit? 

A.  1.  Three  6-volt,  80  ampere-hour  stor- 
age batteries  will  be  required  to  operate 
the  six-inch  spark  coil. 

18  volts  and  4  amperes  is  the  power  con- 
sumed by  the  coil.  About  30  miles  can  be 
covered  with  this  outfit. 

Q.  2.  Does  a  helix  step  up  the  voltage, 
or  amperage  or  does  it  step  up  both? 

A.  2.  A  helix  does  not  necessarily  step 
up  the  voltage  or  amperage,  but  it  is  used 
to  attain  resonance  of  the  closed  oscilla- 
tory circuit,  and  to  regulate  the  length  of 
the  emitted  oscillatory  wave. 


RADIO  DISTANCE  FORMULA. 

(832.)  Joaquin  Agusty,  San  Juan,  Porto 
Rico,  asks: 

Q.  1.  How  many  pounds  of  No.  14  D. 
C.  C.  wire  will  be  necessary  for  the  pri- 
mary of  \y2"  spark  coil,  core  %V2"  long 
by  yA"  diameter? 

A.  1.  Two  and  a  half  pounds. 

Q.  2.  How  may  I  magnetize  a  piece  of 
iron  in  order  to  make  a  permanent  magnet 
in  any  desired  form? 

A.  2.  The  best  manner  by  which  you  can 
magnetize  a  piece  of  steel  (not  iron)  of 
any  desired  shape  is  to  wind  four  to  six 
layers  of  No.  20  B.  &  S.  magnet  wire 
around  the  iron,  which  is  to  be  magnetized 
and  passing  a  current  of  electricity  thru 
it.  Care  should  be  taken  to  see  that  the 
current  is  a  uni-directional  one  or  direct 
current  and  this  source  is  best  obtained 
from  a  storage  battery  or  direct  current 
dynamo. 

Q.  3.  Which  is  the  formula  used  to  com- 
pute the  range  in  miles  of  a  radio  re- 
ceptor? For  example,  a  complete  receiv- 
ing set  with  coupler  and  suitable  antenna 
and  'phones,  tunable  to  3,000  meters,  what 
is  the  maximum  distance  for  receiving  sig- 
nals in  good  weather  conditions? 

A.  3.  There  is  no  formula  which  gives 
the  receiving  range  of  a  receptor.  The 
only  formula  of  such  nature  is  adaptable 
to  transmitting  apparatus. 


C, 


HYSTERESIS  VS.  SELF- 
INDUCTION. 

(833).    W.  C.   Phillips,  Julian,  N 
wishes  to  know : 

Q.  1.  Is  hysteresis  the  same  in  a  mag- 
netic circuit  as  self-induction  in  an  electric 
circuit  ? 

A.  1.  Yes. 


TESLA  TRANSFORMER  QUERY. 

(834.)  Wm.  Oshback,  Philadelphia,  says: 
Q.  1.  I  have  a  Thordarson  one  K.  W. 
60  cycles  transformer,  the  voltage  across 
the  secondary  terminals  is  20,000.    Is  the 


All  About  Wireless 


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Can  you  see  the  superiority  of  this  circuit  over  the  old  Marconi? 
Everything  about  electricity — and  wireless  telegraphy — is  told  in  the  brand-new 
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342 


THE  ELECTRICAL  EXPERIMENTER 


September,  1917 


Mesco  Telegraph  Practice  Set 

For  Learning  Telegraph  Codes 

m 


The  Practice  Set  comprises  a  regular  tele- 
graph key,  without  circuit  breaker,  a  special 
high  pitch  buzzer,  one  cell  Red  Seal  Dry 
Battery,  and  four  feet  of  green  silk  covered 
flexible  cord. 

The  key  and  buzzer  are  mounted  on  a 
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secondary  voltage  of  the  above  transformer 
too  high  to  construct  the  24-inch  high  fre- 
quency apparatus  for  medical  and  lecture 
use,  as  given  by  Dr.  Frederick  Finch 
Strong,  in  the  May  and  June  issues?  If 
the  above  case  is  possible  and  the  ratio 
of  the  Tesla  coil  is  1  to  80,  what  will  be 
the  secondary  voltage  of  the  Tesla  coil? 
Why  is  a  rotary  spark  gap  used  between 
the  condenser  and  Tesla  transformer? 

A.  1.  The  voltage  of  the  transformer  is 
sufficient  to  operate  the  Tesla  high  fre- 
quency transformer,  but  regret  to  say  that 
it  is  impossible  to  estimate  the  voltage  ob- 
tained from  such  an  instrument  as  the  con- 
ditions are  entirely  different  from  those  of 
magnetic  type  of  high  tension  transformers. 
The  voltage  of  a  Tesla  transformer  runs 
in  the  neighborhood  of  millions  of  volts 
at  the  secondary  terminals. 

A  rotary  spark  gap  is  used  between  the 
primary  of  the  Tesla  coil  and  the  second- 
ary of  the  Thordarson  transformer  to  in- 
crease the  spark  frequency  of  the  closed 
oscillatory  circuit  which  causes  an  increase 
of  secondary  voltage  and  frequency  in  the 
Tesla  transformer  secondary.  It  also  acts 
more  efficiently  than  a  fixt  gap,  which  tends 
to  arc  and  heat  up. 


BRAKE  HORSE-POWER 
CALCULATION. 

(835.)  Earl  Lea,  Memphis,  Tenn.,  asks: 
Q.  How  would  you  calculate  the  brake 
horse-power  of  a  motor  when  the  follow- 
ing data  is  on  hand?  The  lever  arm  of  the 
brake  is  3  feet  long  and  the  reading  of  the 
scales  is  30  lbs.,  when  the  motor  is  run- 
ning 1,000  R.  P.  M. 

A.  1.  The  following  formula  gives  the 
relation  of  the  factors  named  with  that  of 
the  brake  horse-power : 

27TLNW 

B.H.P.  =   

33,000 

Where  277"  —  constant. 

L    =  length  of  lever  arm  in  feet. 
N  —  revolutions    per    minute  of 
shaft. 

W  —  force  in  pounds  at  end  of 
lever  arm  as  measured  by 
scales. 

Substituting  your  values  in  the  above 
formula  we  get : 

27rx3xl,000  x  30 

B.H.P.  =    17.1 

33,000 

Q.  2.  Knowing  the  brake  horse-power  of 
a  motor,  how  would  you  determine  the 
efficiency  of  the  motor? 

A.  2.  It  will  be  necessary  to  determine 
the  electrical  power  taken  by  the  motor 
under  test  and  dividing  the  B.H.P.  by  the 
electrical  horse-power,  multiplied  by  100, 
which  will  give  the  percentage  efficiency 
of  the  motor. 

Q.  3.  What  is  the  nature  and  object  of 
the  commutating  field  produced  by  the  in- 
terpoles  of  a  dynamo? 

A.  3.  Its  object  is  to  assist  commutation, 
that  is,  to  help  reverse  the  current  in  each 
coil,  while  short-circuited  by  the  brush,  and 
thus  reducing  sparking.  The  excitation  of 
the  interpoles  being  produced  by  series 
turns,  the  field  will  vary  with  the  load, 
and  will  if  once  adjusted  give  good  com- 
mutation at  any  one  load,  keep  the  same 
proportion  for  any  other  load,  provided  the 
iron  parts  be  not  too  highly  saturated. 


TELEPHONE  AND  TELEGRAPH 
INTERFERENCE. 


(836.) 


-,  asks : 


Q.  1.  What  are  the  characteristics  of  the 
"D'Arsonval"  currents  mentioned  in  the 
article  "Electricity  and  Life"  in  the  May 
issue  of  The  Electrical  Experimenter? 
How  can  apparatus  be  constructed  for  their 
production? 

(Continued  on  page  343) 


SPY  AERIALS. 

(Continued  from  page  300) 
third  story  of  a  brick  dwelling.  This  is  not 
fiction,  but  an  actual  fact,  and  consider  for 
the  moment  that  such  an  iron  fire-escape 
is  very  much  smaller  compared  to  the  metal 
fence,  which  may  run  for  several  hundred 
feet  or  more. 

Fig.  10  shows  two  other  novel  schemes, 
which  a  desperate  enemy  might  employ  to 
signal  his  confederates.  The  first  of  these 
is  the  ordinary  railroad  track  which  in- 
variably rests  on  wooden  ties,  and  it  would 
not  be  very  difficult  at  all  to  thoroly  dis- 
guise the  connecting  wire  from  the  rail- 
road track  to  the  apparatus,  even  by  digging 
a  small  ditch  and  covering  it  over.  The 
operator  might  even  have  the  temerity  and 
good  sense  to  use  a  nearby  house  or  shanty, 
which  no  one  would  ordinarily  suspect,  ana 
moreover  he  might  only  visit  the  scene  of 
these  operations  at  night,  which  would 
naturally  make  his  detection  and  apprehen- 
sion extremely  difficult. 

Many  of  our  office  buildings  are  fitted 
with  extensive  metallic  grill  work  enclos- 
ing elevator  shafts  and  the  like,  which  are 
very  often  insulated  from  the  ground,  and 
thus  provide  another  chance  for  an  enemy 
to  receive  wireless  messages. 

The  ordinary  motor-boat  may  appear 
peace-like  enough  when  speeding  along  the 
coast,  but  it  is  not  improbable  that  such 
a  vessel  might  contain  an  enemy  wireless 
outfit.  It  is  easy  to  see  that  if  such  a  boat 
could  be  at  large  along  the  coast,  that  it 
would  cause  considerable  trouble,  as  on  the 
one  hand  it  could  readily  intercept  radio 
messages  from  shore  by  means  of  a  con- 
centrated antenna  as  shown  in  Fig.  11,  and 
the  wires  of  which  might  even  be  placed 
between  an  inner  or  outer  hull  to  defy  de- 
tection, and  on  the  other  hand,  such  a  float- 
ing information  base  could  readily  com- 
municate with  a  submarine  or  "raider." 

Finally,  we  come  to  the  use  of  the  con- 
centrated radio  antenna,  of  the  type  de- 
scribed some  months  ago  in  The  Elec- 
trical Experimenter,  and  which  was 
tested  with  extreme  satisfaction  at  the  radio 
laboratory  of  Union  College.  It  is  not 
at  all  difficult  to  see  that  a  radio  Spy  who 
knew  his  business  could  readily  deceive 
most  anyone  for  an  indefinite  length  of 
time  by  simply  constructing  one  of  these 
concentrated  aerials  which  could  be  erected 
between  the  real  wall  of  a  room  and  a  false 
partition  or  wall  covering.  If  a  room  hap- 
pened to  be  small,  it  would  be  readily  pos- 
sible of  course  to  use  more  than  one  of 
these  concentrated  aerials,  placing  them  on 
various  walls  of  the  room,  and  covering 
them  over  with  a  board  partition,  or  in 
some  other  way  cleverly  disguising  the 
presence  of  the  aerial. 

Of  course  the  every-ready  radio  inspec- 
tor will  tell  you  that  the  wireless  Spy  can- 
not exist  for  any  length  of  time,  and  in 
fact  for  on1y  a  short  time,  for  the  reason 
that  the  Government  experts  are  equipt 
with  the  latest  radio-locating  and  detect- 
ing instruments,  which  enable  the  inspec- 
tors to  rapidly  close  in  on  any  suspicious 
wireless  wave,  and  to  thus  locate  the  ap- 
paratus. 

But  this  is  not  all  of  the  story  by  any 
means,  as  there  has  been  perfected  in  the 
last  year  or  two  a  particularly  clever  wire- 
less system  of  which  but  little  is  known, 
but  which  utilizes  for  one  thing  an  inaudible 
note,  or  in  other  words  an  undamped  wave, 
and  messages  when  transmitted  by  this  sys- 
tem are  not  sent  out  in  a  continuous  series 
of  signals,  but  in  an  intermittent  series  of 
signals,  all  of  which  characters  are  event- 
ually recorded  on  a  special  receiving  instru- 
ment, which  co-relates  individual  charac- 
ters, so  that  eventually  the  Spy  at  the  re- 
ceiving end  has  before  him  the  original 
message,  in  a  secret  code  to  be  sure. 


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September,  1917 


THE  ELECTRICAL  EXPERIMENTER 


343 


A.  1.  The  characteristics  of  D'Arsonval 
currents  are  of  such  nature  that  they  pro- 
duce continuous  uni-directional  impulses. 
They  are  usually  of  lower  potential  than 
Tesla  currents. 

Q.  2.  Can  a  telegraph  set  be  used  (with- 
out interference  with  telephone  service) 
employing  one  wire  of  the  city  telephone 
system  and  using  the  ground  as  a  return, 
if  the  telegraph  message  was  to  go  thru 
the  central  station  switchboard?  If  this  is 
possible,  please  give  hook  up. 

A.  2.  Yes,  we  would  suggest  that  you  re- 
fer to  the  article  on  page  197  of  the  July 
issue  of  this  journal. 

Q.  3.  How  far  can  messages  be  ex- 
changed by  means  of  the  inductive  wireless 
telephone  described  in  the  May  issue  of  the 
"E   E  "  ^ 

A.  3.  30  to  100  feet. 


PRODUCTION  OF  ELECTRIC 
OSCILLATIONS 

(837.)  Otto  Patersen,  Camden,  N.  J,  de- 
sires information  as  to: 

Q.  I.  What  is  the  best  way  to  generate 
electric  oscillations  of  any  desired  fre- 
quency? 

A.  1.  There  are  several  ways  by  which 
electric  oscillations  can  be  generated,  viz., 
by  means  of  the  electric  arc,  alternator, 
metallic  arc,  and  vacuum  tube  or  Oscil- 
lion.  The  last  contrivance  is  the  most  con- 
venient for  such  work. 

Q.  2.  Is  the  Chaffee  gap  adaptable  for 
radiophonic  work? 

A.  2.  Yes. 

Q.  3.  What  are  the  main  features  of  the 
Chaffee  gap? 

A.  3.  The  use  of  aluminum  and  copper 
spark  electrodes  are  the  fundamental  fea- 
tures of  this  particular  gap. 


ELECTROMAGNET  TO  FRY  EGGS. 

(838.)     P   A  ,  Chicago,  111., 

wishes  information  on  the  large  A.C.  elec- 
tro-magnet described  in  the  March,  1917, 
issue  of  this  journal  by  Raymond  Francis 
Yates. 

A.  1.  We  believe  that  the  large  electro- 
magnet as  described  in  the  article  by  Mr. 
Yates  will  perform  its  work  satisfactorily; 
the  strength  of  the  same  is  due  to  the 
product  of  the  current  in  amperes,  multi- 
plied by  the  number  of  turns  of  wire  in 
the  coils.  You  will  thus  see  that  if  the 
current  is  kept  constant  and  the  number 
of  turns  increased,  you  will  gain  consider- 
ably thereby. 

On  the  other  hand,  with  a  constant  source 
of  potential  or  voltage  an  increased  number 
of  turns  will  simultaneously  increase  the 
resistance  of  the  coil  which  will  reduce  the 
current  passing  thru  it.  Therefore,  it  is 
quite  possible  that  in  some  cases  the  total 
result  will  be  less  than  expected,  or  even 
attained,  with  a  less  number  of  turns, 
owing  to  the  reduced  current. 
*  However,  with  the  electro-magnet  in 
question  it  will  be  possible  to  increase  its 
strength  by  increasing  the  turns  as  you 
suggest  for  the  reason  that  this  magnet  is 
not  designed  for  the  full  line  potential, 
and,  therefore,  you  can  adjust  the  current 
so  as  to  keep  it  constant  with  the  increased 
turns  by  means  of  a  resistance  or  reactance 
coil. 

For  most  exneriments,  and  particularly 
those  cited  by  Mr.  Yates,  the  electro-mag- 
net must  be  excited  by  alternating  current; 
not  direct  current.  It  will  require  con- 
siderable resistance  in  series  if  used  on 
direct  current  as  much  more  current  will 
then  flow. 


THE  BACHELET  LEVITATION 
RAILWAY. 

(839.)  Edward  A.  Brand,  Springfield, 
111.,  writes  us : 


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344 


THE  ELECTRICAL  EXPERIMENTER 


September,  1917 


A 


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Q.  1.  Where  can  I  obtain  information 
on  the  Bachelet  electrical  levitation  system? 

A.  1.  Relative  to  some  literature  or 
books  describing  the  electrical  levitation 
system  of  Emile  Bachelet,  would  suggest 
that  you  take  up  this  matter  with  our  Book 
Department. 

You  might  also  obtain  some  very  val- 
uable information  in  this  direction  by  com- 
municating with  the  Bachelet  Medical 
Apparatus  Co.,  320  Schermerhorn  St., 
Brooklyn,  N.  Y.,  who  represent  Mr.  Bache- 
let in  this  country. 


4  K.W.  TRANSFORMER  QUERY. 

(840.)  Ralph  H.  Seipel,  Elwood  City, 
Pa.,  sends  us  design  of  4  K.W.  trans- 
former on  which  he  wants  advice. 

A.  1.  It  would  seem  that  the  transformer 
you  describe  will  be  all  right  to  operate 
at  a  load  of  4  K.W.  at  intermittent  periods 
as  you  mention.  The  size  of  the  primary 
wire  is  correct  and  agrees  with  the  designs 
usually  followed  in  this  work. 

With  respect  to  the  number  of  primary 
turns  to  be  connected  in  circuit  for  the  dif- 
ferent kilowatt  in-puts,  this  would  work 
out  as  follows  : 

The  secondary  voltage  will  vary  inversely 
as  the  number  of  primary  turns,  i.e.,  as 
the  number  of  primary  turns  in  the  cir- 
cuit are  reduced  the  secondary  potential  will 
increase  and  vice  versa.  We  have  not 
investigated  the  entire  design  of  your 
transformer,  but  presume  that  with  all  of 
the  primary  turns  in  circuit,  that  you  have 
so  proportioned  the  windings  and  the  iron 
core,  that  it  will  take  1  K.W.  from  the 
primary  mains  or  develop  1  K.W.  in  the 
secondary  winding.  If  such  is  the  case, 
then  with  50  primary  turns  in  circuit,  the 
secondary  potential  will  be  twice  that  with 
100  turns,  and  the  output  of  the  trans- 
former will  be  doubled  or  2  K.W.  The 
secondary  current  remains  approximately 
the  same.  With  25  primary  turns  in  cir- 
cuit, the  inverse  ratio  would  then  be  as 
4  to  1,  and  the  secondary  potential  would 
be  four  times  that  with  100  primary  turns 
and  the  output  of  the  transformer  4  K.W. 


ELECTROLYTIC  RECTIFIER 
TROUBLES. 

(841.)    Mr.  H.  C.  B  ,  Ft.  Towson, 

Okla.,  writes : 


a/. 

Storage 
Bo/rer/es 


a/ 


Sfcpdotm 
fransf 
/ 


rect'f/er 


-±-1  4/um/num* 
+  wire 


® 


Proper  Connections  for  Electrolytic  Rectifier 
and   Step-down  Transformer. 

Q.  1.  I  have  tried  to  get  my  electro- 
lytic rectifier  working,  but  can  not  get  it 
to  rectify. 

A.  1.  We  have  noted  what  you  have  to 
say  concerning  the  electrolytic  rectifier.  In 
the  first  place,  there  is  no  question  at  all 
as  to  whether  the  aluminum-lead  or  alu- 
minum-iron rectifier  will  rectify,  for  it  cer- 
tainly will. 

There  are  several  particular  reasons  why 
these  rectifiers  do  not  apparently  work  to 
their  proper  efficiency  at  first.  One  of  the 
most  important  of  these  is  that  the  alu- 
minum plates  must  become  properly  formed 
by  electrolytic  action,  and  it  can  only  do 
so  in  many  cases,  or  at  least  in  a  majority 
of  cases,  where  it  is  possible  to  pass  direct 
current  thru  the  rectifier  for  a  short  time. 


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September,  1917 


THE  ELECTRICAL  EXPERIMENTER 


345 


Otherwise  this  forming  current  may  be  sup- 
plied from  a  110  volt  A.C.  line  with  some 
lamps  in  series,  allowing  considerable  cur- 
rent to  pass  thru  it  for  a  short  period,  or 
until  the  lamps  become  dim,  denoting  that 
the.  gas  film  has  formed. 

Another  reason  why  these  rectifiers  do 
not  always  work  perfectly  at  first,  is  due 
to  the  fact  that  the  solution  may  not  be 
fresh,  and  this  is  a  point  well  worth  look- 
ing into.  The  Editor  remembers  one  par- 
ticularly obstinate  case  of  this  nature  in 
which  he  suggested  that  the  user  take  a 
fine  pen-knife  and  scratch  criss-cross  on 
the  face  of  the  aluminum  plate.  This  will 
sometimes  hasten  the  formation  of  the  fine 
gas  film  which  gathers  on  the  surface  of 
the  aluminum,  and  which  of  course  is  the 
principal  desideratum  in  the  operation  of 
the  electrolytic  rectifier. 

You  might  also  try  a  warm  solution  at 
first,  as  these  rectifiers  work  most  efficiently 
with  a  hot  solution  or  when  a  solution  has 
heated  up  some.  We  have  data  on  a  recti- 
fier of  the  aluminum-lead  type  employing 
a  saturated  solution  of  ammonium  fosfate 
and  which  has  been  tested  at  the  Electrical 
Testing  Laboratories  of  New  York  City. 

If  you  are  sufficiently  interested  in  the 
theory  and  operation  of  ,  this  electrolytic 
rectifier,  we  shall  be  pleased  to  furnish  you 
with  a  duplicate  copy  of  the  engineering 
report  given  by  the  above  laboratory  at  a 
charge  of  $1. 


EXPERIMENTAL  PHYSICS. 

(Continued  from  page  312) 

the  fourth  time  you  continue  as  before, 
except  that  instead  of  going  past  the  gong 
you  strike  it.  Your  partner  sets  the  stop- 
watch as  he  sees  the  flag  reach  the  ver- 
tical position  on  the  fourth  swing  and 
touch  the  gong,  and  then  stops  the  watch 
when  he  hears  the  sound.  On  looking  at 
the  watch  it  will  be  noticed  that  the  sound 
was  heard  three  seconds  after  the  flag 
reached  the  vertical  position  and  struck 
the  gong.  Since  the  distance  between  you 
and  your  partner  was  3,300  feet  and  it 
required  three  seconds  for  the  sound  to 
travel  that  distance,  we  see  that  the  speed 
of  sound  is  about  1,100  feet  per  second, 
or  about  1,000  miles  per  hour. 

EXPERIMENT  42— The  method  of  Ex- 
periment 41  can  be  carried  out  very  care- 
fully and  the  results  obtained  will  be  quite 
accurate.  For  those  not  having  access  to 
a  stop-watch,  the  following  method  is 
given :  Figure  32  represents  a  light  wooden 
box  4"  by  25"  by  45",  approximately.  A  hole 
is  cut  at  D  and  the  inside  of  the  box 
which  can  be  seen  thru  this  hole  is  painted 
white.  B  is  a  small  block  of  wood  painted 
black  and  attached  to  the  top  of  the  box 
by  a  string  E.  The  length  of  this  string 
and  block  together  should  be  thirty-nine 
inches,  and  when  drawn  to  position  A  or 
C  and  let  go,  it  will  oscillate  back  and 
forth  as  a  pendulum  and  the  black  block 
will  pass  the  white  opening  once  in  each 
second.  If  on  trial  it  does  not  pass  ex- 
actly each  second  it  can  be  slowed  down 
or  speeded  up  by  lengthening  or  shorten- 
ing the  string.  When  it  is  adjusted  it  is 
what  is  known  as  a  Seconds  Pendulum. 
Let  your  partner  pound  loudly  on  the  side 
of  the  box  just  when  the  block  (bob)  B 
passes  the  white  hole  and  keep  doing  so 
each  time  while  you  in  the  meantime  move 
back  away  from  the  pendulum.  As  you 
move  away,  the  pounding  will  be  heard 
after  the  bob  passes  the  white  hole,  and 
keeps  losing  and  losing  until  it  is  lapt  by 
the  bob  and  the  sound  again  coincides 
with  the  bob's  passing  the  white  hole. 
Obviously  since  the  sound  has  been  lapt 
by  the  bob  and  the  pendulum  is  a  seconds 
pendulum,  it  takes  the  sound  just  one  sec- 
ond to  travel  from  the  box  to  you.  On 
measuring  the  distance,  it  is  found  to  be 


about  1,100  feet.  Thus  far  we  have  no- 
ticed that  sound  will  not  pass  thru  a 
vacuum,  but  that  it  will  pass  thru  ordinary 
matter,  and  usually  the  heavier  the  mat- 
ter the  faster  the  sound  travels  thru  it. 

The  Indians  put  their  ears  to  the  ground 
to  hear  the  noise  of  approaching  horses, 
since  the  ground  is  heavier  than  air,  and 
the  sound  travels  faster  and  appears 
louder.  If  two  stones  are  clapt  together 
under  water  the  sound  is  louder  to 
the  person  with  his  ears  in  the  water  than 
to  the  person  with  his  ears  out  of  the 
water.  (If  you  don't  think  so,  try  it!) 
In  air  sound  travels,  always  at  the  same 
speed,  1,100  feet  per  second,  and  all  dif- 
ferent kinds  of  sound,  whether  of  different 
pitch  or  of  different  loudness,  travel  at  the 
same  speed.  Thus  the  gentle  squeak  of 
the  high  string  of  the  violin,  and  the  low 
thump  of  the  bass  drum,  and  the  ear  split- 
ting wail  of  the  cornet  of  the  symphony 
orchestra  of  the  Movie  show  reach  our 
ear  at  the  same  time. 

EXPERIMENT  43— Loosen  a  low  string 
from  some  stringed  instrument,  such  as 
a  banjo,  guitar,  mandolin,  violin,  etc.  If 
now  it  is  plucked  and  gradually  tightened 
until  it  just  gives  off  a  low  musical  note, 
it-  will  be  seen  to  vibrate  rather  slowly. 
"On  tightening  it  a  little  more  we  notice 
that  the  note  given  off  is  of  higher  pitch 
and  that  the  vibrations  are  faster.  This 
I  leads  us  to  the  next  important  principle, 
namely  that  the  pitch  of  a  note  depends 
on  the  frequency  of  vibration  of  the  source, 
i.  e.,  the  faster  the  source  vibrates  the 
higher  the  note.  If  one  looks  inside  the 
piano,  it  will  be  noticed  that  the  bass  notes 
are  given  by  long,  heavy,  loose  strings, 
and  that  the  high  notes  are  given  by  short, 
thin  tight  strings.  The  laws  of  vibrating 
strings  can  be  stated  as  follows : — the 
tighter  the  string  the  faster  it  vibrates  and 
consequently  the  higher  the  pitch  of  the 
note  given  off ;  the  shorter  the  string  the 
faster  it  vibrates  and  consequently  the 
higher  the  pitch  of  the  note.  Pitch  should 
not  be  confused  with  loudness.  Loudness 
depends  upon  the  distance  of  the  sound 
source  from  the  listener.  Also  loudness 
of  a  sound  depends  upon  the  amount  of 
the  disturbance.  A  small  fire-cracker  dis- 
turbs a  small  amount  of  air,  and  the  sound 
is  weak,  while  a  large  salute  disturbs  a 
large  amount  of  air  and  a  loud  bang  re- 
sults. 

EXPERIMENT  44— Obtain  two  me- 
dium-size cans  of  peaches,  or  pears,  or 
whatever  canned  fruit  you  like  best.  Now 
remove  the  tops  and  the  contents  of  the 
cans.  With  a  thin  nail  and  hammer,  punch 
a  whole  in  each  of  the  bottoms  of  the 
cans.  "Borrow"  about  100  feet  of  Pa's 
fishing  line.  Pass  the  ends  thru  the  holes 
in  the  cans  and  tie  them  inside  to  match 
sticks. 

If  now  the  string  is  stretched  as  in  Fig. 
33  and  your  partner  talks  into  his  can, 
you  will  hear  him  distinctly.  When  he  is 
thru  talking  you  can  talk  into  the  can 
and  he  will  hear  you  distinctly.  When 
you  talk  into  your  end  of  this  telephone 
you  cause  the  air  in  the  can  to  vibrate, 
which  in  turn  causes  the  bottom  of  the 
can  to  vibrate.  The  end  of  the  can  causes 
the  tightly  stretched  string  to  vibrate,  and 
the  string  causes  the  bottom  of  your  part- 
■  ner's  can  to  vibrate.  The  bottom  of  his 
can  causes  the  air  in  his  can  to  vibrate 
and  it  in  turn  cause  the  membrane  in  his 
ear  to  vibrate  so  that  he  hears  your  voice. 

In  other  words,  the  disturbance  which 
you  cause  in  the  air  near  your  mouth  has 
been  transmitted  to  the  air  immediately 
near  your  partner's  ear,  which  gives  the 


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346 


THE  ELECTRICAL  EXPERIMENTER 


September,  1917 


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same  effect  as  if  you  were  standing  be- 
side your  partner  and  talking  to  him.  The 
modern  commercial  telephone  works  on  a 
similar  principle.  The  diafram  which 
corresponds  to  the  bottom  of  the  can  in 
our  case,  is  made  to  vibrate  by  the  mo- 
tion of  the  air  caused  by  speaking.  This 
vibration  is  transmitted  electrically  to  the 
receiver  at  the  other  end ;  the  receiver  at 
the  other  end  causes  the  air  at  the  lis- 
tener's ear  to  vibrate  and  the  listener  hears 
the  speaker.  The  electric  auto  horn  con- 
sists essentially  of  a  thin  metal  disk  or 
diafram  which  is  made  to  vibrate  rapidly 
by  the  electric  current  and  the  vibration 
of  the  diafram  causes  a  disturbance  in  the 
air  which  may  herald  the  approach  of  a 
Ford,  a  brass  band,  or  a  cat-call.  The 
phonograph  also  depends  upon  the  vibra- 
tion of  a  disk  or  diafram.  The  needle  is 
attached  to  the  diafram  by  a  small  lever. 
As  the  needle  passes  around  the  record  it 
vibrates  according  to  the  indentations  in 
the  record.  This  vibration  is  communi- 
cated to  the  diafram  by  the  lever.  The 
vibration  of  the  diafram  causes  the  air 
in  the  horn  or  sound  box  to  be  disturbed. 
On  placing  the  thumb  gently  on  the  dia- 
fram (reproducer)  one  can  feel  the  vibra- 
tions. 

It  may  be  well  to  note  just  how  the 
sound  is  transmitted  thru  the  air.  If  a 
half-dozen  billiard  balls  are  placed  in  a 
straight  line  touching  each  other,  and  then 
the  cue  ball  is  made  to  strike  the  end 
ball,  the  ball  at  the  other  end  will  move 
out  and  the  others  will  remain  in  their 
places.  In  the  transmission  of  sound,  in- 
stead of  billiard  balls  we  have  the  molecules 
of  air.  The  molecules  do  not  touch,  but 
are  very  close  together  and  hence  we  get 
only  a  slight  displacement.  The  sound  is 
thus  transmitted  from  molecule  to  mole- 
cule in  all  directions.  Obviously  if  a  mole- 
cule at  the  source  of  the  sound  vibrates 
in  a  certain  way  the  molecule  near  the 
listener  will  vibrate  in  that  very  same  way, 
since  each  individual  motion  has  been 
transmitted  as  it  was  made. 

EXPERIMENT  45— If  ten  or  a  dozen 
olive  bottles  or  other  bottles  are  placed 
in  a  row,  and  partially  filled  with  water 
as  in  Fig.  34,  on  blowing  over  the  tops  a 
thin  flat  jet  of  air,  musical  notes  will  be 
heard.  The  jet  of  air  may  be  secured 
by  blowing  thru  a  rubber  tube  at  the  end 
of  which  is  attached  a  flattened  Bunsen 
burner  wing  tip  which  can  be  purchased 
for  a  few  cents.  On  adding  to  or  sub- 
tracting from  the  water  in  the  various 
bottles  the  various  notes  of  the  musical 
scale  can  be  gotten  and  then  one  can  by 
a  little  practise  learn  to  play  simple  melo- 
dies. This  interesting  experiment  illus- 
trates the  working  of  the  organ  pipe.  A 
thin  flat  jet  of  air  passing  over  a  column 
of  air  causes  the  column  to  vibrate ;  the 
longer  the  column  the  lower  the  note. 

Just  as  a  billiard  ball  on  hitting  the 
cushions  of  the  billiard  table  is  reflected,  so 
when  a  sound  wave  caused  by  the  vibra- 
tion of  a  molecule  hits  an  object,  it  is 
reflected  back.  If  the  reflecting  surface  is 
near,  because  of  the  tremendous  speed  at 
which  the  sound  travels,  the  reflected  sound 
and  the  original  one  are  heard  at  practically 
the  same  time,  simply  re-enforcing  each 
other.  If,  however,  the  distance  is  suffi- 
ciently great,  the  reflected  sound  reaches 
the  air  later,  and  we  call  this  the  echo. 
If  a  sound  is  caused  by  a  source  vibrating 
in  an  irregular  manner,  the  vibrations  in- 
terfere with  each  other  and  the  result  is 
a  noise.  If,  however,  the  source  is  vibrat- 
ing in  a  regular  manner,  the  sound  is  pleas- 
ing and  is  called  a  musical  sound.  Both 
are  disturbances  of  the  air,  but  the  former 
is  a  disturbance  to  those  hearing  it. 
(To  be  continued) 


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September,  1917 


THE  ELECTRICAL  EXPERIMENTER 


347 


ELECTRIC  "BLOODHOUNDS"  TO 
FIND  AND  DESTROY  U-BOATS. 

(Continued  from  page  298) 

inconceivable  how  the  noise  of  these  power- 
ful engines  could  be  deadened  entirely  so 
that  the  super-sensitive  microphone-Audions 
would  not  detect  it,  when  they  once  came 
into  a  reasonable  range. 

The  authors  confidently  look  forward  to 
an  early  trial  of  the  idea,  feeling  convinced 
in  its  feasibility  and  successful  application 
to  the  U-boat  peril. 

The  electric  torpedo  bloodhound  depends 
upon  several  well-known  physical  and  elec- 
trical laws  for  its  mode  of  attacking  and 
destroying  a  submerged  U-boat.  Principal 
among  these  are  the  utilization  of  sound 
waves,  such  as  given  off  by  the  engines  and 
propellers  of  a  submarine,  and  also  the 
principle  of  the  induction  balance.  The 
presence  of  a  metallic  mass  as  for  instance 
a  submarine  hull,  will  upset  the  electrical 
balance  of  two  coils,  which  fact  is  here 
made  use  of  and  which  will  prove  efficacious 
over  a  considerable  distance;  at  least  sev- 
eral hundred  feet,  when  a  sensitive  galvo- 
nometer  relay,  such  as  the  Weston  type,  is 
employed  for  indicating  the  state  of  bal- 
ance in  the  coils.  As  for  the  practical 
range  of  sound  wave  control  thru  water, 
this  scheme  has  been  successfully  applied 
by  the  Allies,  particularly  along  the  French 
coast,  for  detecting  and  locating  submarines 
up  to  twenty  miles  distant.* 

Instead  of  simply  listening  for  the  sound 
of  an  enemy  submersible,  as  in  the  scheme 
just  cited,  the  authors  propose  to  cause 
these  sound  waves  coming  thru  the  water 
to  spell  the  end  of  the  tricky  sub-sea  craft. 
Furthermore,  it  is  evident  both  theoretical- 
ly and  practically,  that  if  we  can  pick  up 
the  sound  of  a  submarine  five  miles  away 
and  amplify  it  so  as  to  make  it  plainly 
audible  in  a  telephone  receiver,  that  it  is 
certainly  possible  to  cause  this  same  sub- 
aqueous wave  to  actuate  a  properly  tuned 
and  sensitive  microphone,  which  in  turn 
actuates  an  Audion  amplifier  (or  Brown 
telephone  relay).  This  device  then  closes 
or  opens  certain  local  control  circuits  con- 
nected to  the  propeller,  rudder  and  diving 
plane  mechanism  of  a  special  torpedo  of 
the  general  type  illustrated. 

Of  course  someone  will  immediately  ask : 
"Why  not  make  the  device  full  automatic 
and  turn  it  loose  in  a  submarine  infested 
area?"  This  sounds  like  good  logic  and 
possibly  is  under  certain  limited  conditions, 
but  we  must  not  forget  that  our  electric 
submarine  "bloodhound"  would  have  no 
scruples  about  attacking  friend  as  well  as 
foe;  steamer  as  well  as  submarine.  There- 
fore, it  seems  the  best  logic  to  attach  one 
of  these  torpedoes  to  a  submarine  chaser 
by  means  of  a  flexible  electric  cable,  which 
is  attached  to  an  automatic-release  drum. 
The  commander  of  the  mother-ship  thus 
retains  control  over  the  ever-vicious  U- 
boat  "bloodhound,"  which,  once  it  hears  a 
submersible  purring  away  in  the  briny 
depths,  immediately  proceeds  to  dive 
straight  for  it.  prepared  to  sink  the  sus- 
pected craft,  whether  friend  or  foe  and 
which,  if  made  full  automatic,  would  blow 
the  under-sea  fighter  to  bits,  without  any 


*See  article  describing  the  method  of  applying 
the  sound  wave  detector  for  submarine  detec- 
tion and  location  in  the  January,  1916,  issue  of 
The  Electrical  Experimenter. 


parleying  whatsoever.  For  these  and  other 
obvious  reasons  it  is  best  to  retain  control 
of  the  electric  torpedo. 

As  seen  in  the  illustration,  Fig.  1,  the 
electric  "bloodhound"  has  quite  an  in- 
teresting internal  make-up.  In  general, 
there  are  two  induction  balance  coils  ar- 
ranged on  port  and  starboard  of  the  nose 
as  shown  clearly  in  the  front  cover  illus- 
tration. The  forward  compartment  con- 
tains also  a  powerful  electromagnet  for 
holding  the  torpedo  against  the  submarine 
hull;  a  special  signaling  electromagnet  is 
provided  as  shown,  which,  when  intermit- 
tently excited  by  means  of  a  telegraph  key 
on  the  bridge  of  the  submarine  chaser, 
causes  the  sliding  brass  rod  inside  the  hold- 
ing magnet  core  to  work  up  and  down. 
Thus  it  becomes  possible  to  telegraph  the 
Herr  Commander  of  the  U-boat,  that  un- 
less he  will  arise  at  once  and  surrender  he 
will  be  blown  to  bits  by  the  200  pounds  of 
gun  cotton  in  contact  with  his  craft.  More- 
over, the  U-boat  officer  can  reply  by  tele- 
graphic signals  sent  out  thru  his  regular 
electric  under-water  sound  telegraph,  the 
signals  being  picked  up  either  by  one  of 
the  microphones  on  the  electric  torpedo  or 
by  a  regular  sound  wave  telegraph  receiver 
of  the  Fessenden  type,  as  used  by  practi- 
cally all  ships  today. 

The  forward  compartment  also  contains 
the  interrupter,  battery,  etc.,  for  exciting  the 
coils  of  the  induction  balance,  details  of 
this  apparatus  being  given  in  Fig.  2.  Note 
that  the  secondary  coils  of  the  balance  are 
connected  to  a  super-sensitive  galvanometer 
relay,  which  acts  to  close  certain  control 
circuits  going  to  the  rudder,  plane  and  pro- 
peller solenoid  mechanism.  This  apparatus 
comes  into  control  of  the  "bloodhound" 
when  the  microphone  control  has  brought  it 
to  within  a  few  hundred  feet  of  the  sub- 
mersible, where  sound  reverberations  would 
tend  to  throw  the  microphone  control  some- 
what off.  Several  sets  of  tuned  micro- 
phones are  placed  along  the  top  and  bot- 
tom, as  well  as  the  sides  of  the  torpedo  as 
indicated. 

The  next  compartment  would  contain  the 
explosive,  usually  gun  cotton,  to  be  deto- 
nated when  desired  by  throwing  a  switch 
on  the  submarine  chaser.  The  center  space 
is  occupied  by  an  electric  gyroscope,  used 
for  stabilizing  the  torpedo,  also  solenoid 
magnets  for  controlling  the  diving  and 
raising  planes  on  the  exterior  of  the  hull. 

Next  we  come  to  the  mast.  This  is  hol- 
low to  permit  of  the  electric  control  cable 
and  pilot  lamp  cable  passing  down  thru  it 
to  the  interior  of  the  torpedo.  The  pilot 
lamp  (fitted  with  semi-circular  reflector  to 
throw  light  toward  tender  vessel)  and  flag 
are  carried  on  a  short  pole  mounted  on  a 
weighted  ball-float  as  illustrated.  If  the 
"bloodhound"  takes  the  "scent"  and  dives, 
the  ball-float  automatically  releases  and 
floats  on  the  surface  of  the  water  for  the 
guidance  of  the  officers.  The  pilot  lamp 
(for  night  work)  is  supplied  with  electric 
current  thru  a  flexible  cable  which  reels 
out  from  an  automatic  drum  in  the  manner 
apparent.  The  movements  of  the  torpedo 
can  thus  be  gaged  quite  accurately. 

Passing  to  the  next  "aft"  compartment, 
this  is  devoted  to  the  batteries,  relays,  am- 
plifiers and  other  auxiliary  electric  control 
instruments.  Behind  this  there  come  the 
propeller  motor  and  rudder  control  sole- 
noid magnets.    See  Fig.  1. 


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348 


THE  ELECTRICAL  EXPERIMENTER 


September,  1917 


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The  diagram,  Fig.  3,  shows  the  circuits 
for  the  retaining  and  signaling  electro- 
magnets in  the  nose  of  the  torpedo.  The 
smaller  or  signaling  magnet  is  controlled 
by  a  telegraph  key  on  the  submarine  chaser 


peculiar  control  circuits  necessary  to  bring 
about  the  results  already  described,  and 
particularly  the  method  used  to  prevent 
the  torpedo  from  striking  the  propellers  of 
the  enemy  sub-sea  fighter.    The  principal 


^^Topm/cr.  dmpl'fers 


r2  Sot 
Bat  m/cr 

-Sac/nd  ware 


Sat.       /  Sat. 

kfies.  Fotar 
re/ot/  s,ooo  to 
/o.  ooo  otr/ns 


To  second  c/rcu/t  of 
compound  wound  - 
motor 


Prope/kr 


To  tender 
supptc/com 


D/woo  &r/sJoq 
P/ahes  ~ 


Ccntro/' 
5o/e/7o/ds 


Microphone  Connections  to  Various  Amplifier, 

Electric  U-boat 

as  aforementioned.  The  holding  magnet 
coil  would  be  excited  as  soon  as  the  tor- 
pedo started  in  motion,  or  it  could  be  ar- 
ranged to  be  excited  only  when  the  torpedo 
had  approached  to  within  a  few  feet  of  its 
prey. 

Many  readers  will  no  doubt  be  sufficient- 
ly interested  in  this  almost  human  sub- 
marine annihilator  to  study  some  of  the 


AtOSTEBW&ALtWIHE 


BOOK 
&  FORvM 
EVEFvY 
INVENTOR 
SHOULD 
U5E 


*  ^  ATTORNEYS 

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283 
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Relay  and  Solenoid  Control  Circuits  In  the 
"Bloodhound." 

electric  control  functions  are  outlined  in 
the  diagram,  Fig.  4,  which  will  help  to  make 
clear  how  the  device  actually  steers  its 
own  course  toward  the  invisible  enemy. 

First,  we  have  the  four  distinct  sets  of 
tuned  microphones,  disposed  on  the  top, 
bottom  and  two  sides  of  the  torpedo.  These 
microphones  are  designed  especially  to  re- 
spond to  the  peculiar  note  given  off  by  the 
engines  and  propellers  of  a  submarine  and 
thus  do  not  respond  to  the  sound  of  the 
torpedo's  propellers  or  that  of  the  tender 
ship.  It  is  also  possible  to  shield  the  micro- 
phones so  that  they  will  not  be  affected  by 
the  sound  of  the  torpedo's  propellers. 

Keeping  in  mind  the  location  of  the  four 
sets  of  microphones  or  sound  detectors,  it 
is  easy  to  understand  that  if  these  are  prop- 
erly connected  to  the  control  mechanisms, 
that  a  sound  wave  emanating  (generally 
speaking)  from  any  one  of  four  directions 
will  cause  the  "bloodhound"  at  once  to 
start  in  that  particular  direction,  i.  e.,  it 
may  dive  either  up  or  down,  right  or  left, 
or  in  some  angular  direction  between  these 
by  the  co-action  of  two  sets  of  control 
apparatus. 

As  will  be  observed  the  propeller  motor 
is  compound  wound  so  as  to  be  controlled 
by  both  sets  of  relays,  i.  e.,  those  controll- 
ing the  rudder  solenoids  or  those  working 
the  diving  plane  solenoids.  The  supply 
cable  from  the  tender  furnishes  current  for 
the  propeller  motor  as  the  diagram  shows. 

The  mode  of  action  will  best  be  seen  by 
considering  that  for  instance  a  sound  wave 
strikes  microphone  No.  2,  on  the  bottom 
of  the  torpedo.  The  resistance  of  the 
microphone  is  changed,  causing  the  am- 
plifier A.  2,  to  act  simultaneously.  The 
latter  device  boosts  the  microphone  signal 
several  hundred  times  in  strength,  enab- 
ling the  high  resistance,  polarized  relay  P2 
to  close  its  local  circuit  to  special  relay 
R.  2. 

This  relay,  R.  2  (and  its  brothers,  R.  1, 
R3  and  R4)  are  provided  with  special 
armatures,  having  insulated  contact  arms 
on  them  as  shown.  Hence,  when  the  sound 
wave  has  finally  caused  relay  R.  2  to  close, 
(Continued  on  page  351) 


ion  benefit  by  mentioning  "The  Electrical  Experimenter"  when  writing  to  advertisers. 


September,    I  9  I  7 


THE  ELECTRICAL  EXPERIMENTER 


349 


Edited  by  H.  GERNSBACK 

In  this  Department  we  publish  such  matter  as  is  of  interest  to  inventors  and 
particularly  to  those  who  are  in  doubt  as  to  certain  Patent  Phases.  Regular  inquiries 
addrest  to  "Patent  Advice"  cannot  be  answered  by  mail  free  of  charge.  Such  inquiries 
are  publisht  here  for  the  benefit  of  all  readers.  If  the  idea  is  thought  to  be  of  im- 
portance, we  make  it  a  lule  not  to  divulge  details,  in  order  to  protect  the  inventor  as 
far  as  it  is  possible  to  do  so. 

Should  advice  be  desired  by  mail  a  nominal  charge  of  $1.00  is  made  for  each 
question.  Sketches  and  descriptions  must  be  clear  and  explicit.  Only  one  side  of 
sheet  should  be  written  on. 


COMBINATION  SWITCH  SPARK 
GAP. 

(170.)  Claude  H.  jonnson  of  Leoti,  Kan- 
sas, has  sent  in  a  very  clever  design  of  a 
combined  antenna  switch  spark  gap  and 
lightning  protector,  and  wishes  to  have  our 
advice  on  this  design.  Mr.  Johnson  wishes 
to  know  if  the  idea  is  practical  and  whether 
a  patent  may  be  obtained,  etc. 

A.  The  idea  looks  feasible  to  us,  and  has 
several  points  in  its  merit.  While  a  patent 
might  be  obtained  on  this  invention,  we 
have  little  hope  that  this  will  be  remunera- 
tive financially,  for  the  simple  reason  that 
there  is  no  market  for  radio  devices  at  the 
present  time.  However,  after  the  close  of 
the  war,  this  might  be  worked  up  into  a 
profitable  patent.  The  idea  is  as  good  as  it 
is  novel. 


NOVELTY  FAN. 

(171.)  Sidney  Brown  of  Lake  Charles, 
La.,  has  submitted  to  us  an  illustration  and 
description  of  novelty  lights  to  be  installed 
in  a  ceiling  fan.  Our  correspondent  would 
like  to  have  our  opinion  as  to  whether  this 
is  a  practical  invention,  and  whether  it 
would  be  worth  while  to  have  it  patented. 

A.  While  the  idea  is  novel,  we  think  the 
device  would  cause  too  much  flickering.  In 
other  words,  the  light  would  be  quite  un- 
steady, and  would  hurt  the  eyes  of  whoever 
is  in  the  vicinity  of  this  fan.  It  might  be 
all  right,  however,  for  advertising  purposes, 
and  we  would  advise  our  correspondent  to 
get  in  touch  with  a  patent  attorney. 


PATENT  QUESTIONS. 

(172)  Alif  Byran  of  Nephi,  Utah, 
wants  to  know  : 

Q.  1.  How  does  a  person  obtain  a  patent? 

A.  1.  There  are  two  ways  of  obtaining  a 
patent.  You  can  prepare  jour  own  patent 
drawings,  and  describe  the  application  of 
the  patent  yourself  by  writing  up  speci- 
fications in  a  certain  manner,  and  sending 
them  to  the  patent  office,  paying  the  govern- 
ment fee  of  $20.00. 

It  is  safe  to  say.  however,  that  not  one 
in  ten  thousand  inventors  ever  take  out 
their  own  natents,  as  they  have  no  tech- 
nical experience  in  preparing  the  drawings 
and  presenting  the  claims  in  a  legal  manner. 

The  right  way  is  to  employ  a  capable 
patent  attorney,  such  as  you  will  find  listed 
in  our  advertising  columns,  and  this  is  not 
only  the  cheapest  in  the  long  run,  but  the 
best  method. 

Q.  2.  What  does  a  patent  usually  cost? 

A.  2.  It  is  impossible  to  state  this  in  fig- 
ures as  it  depends  entirely  upon  the  article 
to  be  patented.  Some  patents  are  so  simple 
that  they  only  need  a  small  drawing  and 
very  little  explanatory  text,  and  the  claims 
are  perhaps  few  and  simple.  Other  patents 
need  *>  a  great  many  illustrations  which 
necessitates  several  sheets  of  drawing,  and 
we  have  seen  patents  that  have  from  twenty 
to  twenty-five  printed  pages  of  text,  and 
anywhere  up  to  100  claims.  Naturally  such 
patents  cost  a  great  deal  more.    It  all  de- 


pends how  much  work  the  patent  attorney 
has  to  put  into  the  application.  Usually 
the  patent  attorney  will  tell  you  haw  much 
he  is  likely  to  charge  for  his  work.  The  gov- 
ernment lee  is  ot  course  always  the  same, 
no  matter  whether  the  patent  is  a  long  or 
short  one.  The  fee  is  $20.00  with  the  appli- 
cation, and  then  there  is  a  final  fee  when 
the  patent  is  allowed  of  $20.00  also. 

Q.  3.  Can  you  always  get  a  manufactur- 
ing company  to  manufacture  a  patented 
idea  if  it  is  a  good  one? 

A.  3.  If  the  idea  is  of  merit,  there  cer- 
tainly should  not  be  much  trouble  in  dis- 
posing of  the  patent  to  some  reputable 
concern;  that  is,  if  the  idea  is  really  a  good 
one.  As  a  rule,  there  is  a  market  for  every- 
thing good  and  practical,  and  while  it  may 
take  time  and  trouble  to  find  the  right 
concern,  if  the  patent  is  really  a  meri- 
torious one,  it  can  as  a  rule  be  disposed  of. 


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Name  Address  


350 


THE  ELECTRICAL  EXPERIMENTER 


September,  1917 


i 


I  was  very  much  pleased  with  the  neat  and 
compact  looks  of  the  "RADIOTONE."  I  have 
not  seen  one  buzzer  that  can  heat  it  for  twice 
or  THREE  TIMES  THE  PRICE.  I  use  it  for 
finding  the  sensitive  part  of  the  mineral  in  my 
crystal  detecter  and  for  learning  to  receive  mes- 
sages when  connected  with  one  or  more  receivers, 
and  a  telegraph  key  to  break  the  circuit.  I  also 
wish  to  say  that  I  think  that  any  one  who  in- 
vests 90c  in  a  "RADIOTONE"  will  be  better 
pleased  with  the  results  in  the  short  as  well  as 
long  run  than  any  other  buzzer  that  costs  twice 
the  price. 

PRIVATE  P.  H.  REMPBL,  4th  Co.,  C.  A.  C. 

U.  S.  ARMY,  Ft.  Rosecrans,  Calif. 


I  wish  to  say  that  your  "RADIOTONE"  Buz- 
zer works  better  than  I  ever  thought  it  would, 
and  I  don't  think  there  is  a  BETTER  BUZZER 
ON  THE  MARKET.  It  also  gives  a  very  classy 
appearance  to  any  wireless  outfit.  It  cannot  be 
praised  too  highly. 

PERRY  CRAWFORD, 
13  Ten  Broeck  St.,  Albany,  N.  X. 


I  have  given  vour  "RADIOTONE"  Buzzer  a 
thoro  test  and  find  it  to  give  VERY  GOOD  SAT- 
ISFACTION. Also  that  I  am  very  much  pleased 
with  it  and  that  it  comes  up  to  my  expectations. 
I  would  recommend  it  to  all  learners  as  a  very 
good  Buzzer.  In  case  I  have  any  more  orders 
I  will  extend  them  to  you. 

W.  H.  CRUDGINGTON. 
V.  S.  S.  UTAH,  Box  E,  care  of  P.  M. ,  N.  Y. 


I  received  my  "RADIOTONE"  Buzzer  a  few 
days  ago.  and  have  tried  it  out  in  a  number  of 
ways.  It  is  exactly  like  you  describe  it,  and  one 
of  the  biggest  advantages  of  it  is  that  the  sound 
Is  always  EXACTLY  WHERE  YOU  WANT  IT. 
right  in  the  receivers.  It  is  by  far  the  best  buz- 
zer I  have  seen  on  the  market.  It  has  also  a 
verv  beautiful  appearance,  and  has  one  of  the 
CLEAREST  AND  HIGHEST  PITCHED  TONES 
any  buzzer  that  I  have  yet  come  across.  Thank- 
ing you  again  for  your  wonderful  buzzer,  I  am. 
Yours  verv  trulv. 

HOWARD  A.  PAGE. 
000  Harrison  St.,  Lynchburg,  Va. 


Your  "RADIOTONE"  Buzzer  certainly  came 
up  to  all  my  expectations.  Its  tone  is  exactly 
like  that  heard  in  a  regular  wireless  phone.  It 
is  not  affected  by  high  altitude  nor  damp 
weather.  It  is  as  beautiful  an  instrument  as  one 
could  wish  to  see.  IT  IS  SILENT.  That  is 
the  most  important  of  all  in  the  work  for  which 
I  use  it.  It  produces  a  clearer  and  higher- 
pitched  tone  on  less  current  than  a  buzzer  of 
any  other  make  that  I  have  tried.  IT  HAS 
NEVER  STUCK  nor  FAILED  TO  RESPOND 
instantly  to  the  application  of  current  since  I 
have  had  it.  I  wish  you  and  the  E.  I.  Co. 
every  success  and  I  will  do  everything  in  mv 
power  to  help  you  as  you  are  a  PROMPT  AND 
SQUARE  DEALING  COMPANY. 

O.  M.  McBURNEY, 
Fort  Bayard,  N.  Mex. 


I  wish  to  say  that  your  "RADIOTONE"  Buz- 
zer is  the  only  test  buzzer  that  I  have  seen  in 
which  I  can  find  NO  fault  whatever.  I  re- 
ceived it  in  good  condition  and  it  is  that  way 
now.  THOUGH  I  ACCIDENTALLY  DROPPED 
IT  SEVERAL  FEET.  I  am  using  it  on  a  code 
practicing  set.  It  has  the  best  tone  of  any 
buzzer  that  I  have  seen. 

LESTER  SHIPLEY. 
Care  of  .1.  O.  Tate  Electric  Co. 
118  Main  St.,  Bedford,  Va. 


I  have  given  the  "RADIOTONE"  Buzzer 
which  I  have  received  from  the  E.  I.  Co.  a 
thoro  test  and  And  it  satisfactory  in  all  re- 
spects. I  also  used  other  buz-ers.  but  the 
"RADIOTONE"  IS  THE  BEST  THAT  I  HAVE 
EVER  USED  and  BEYOND  MY  EXPECTA- 
TIONS. The  other  goods  that  I  received  are  also 
satisfactory. 

A.  WITHER. 
Muir,  Pa. 


I  am  ven*  pleased  to  say  that  I  am  satisfied 
With  the  results  obtained  from  the  "RADIO- 
TONE"  Buzzer.  It  gives  a  really  WONDER- 
FUL IMITATION  OF  A  WIRELESS  MES- 
SAGE. GEORGE  DTMON 

Lavallette,  N.  J. 


ELECTRO    IMPORTING  CO. 

231  Fulton  Street  New  York  City 


FROM  A   RADIO  EXPERT 
The  "RADIOTONE"  Buzzer  which  the  E,  I.  Co.  sent  me  some 
time  ago  has  been  thoroly  tested  out  in  my  Laboratory,  and  I 
am  very  pleased   to  give  you   my  opinion   concerning   its  per- 
formance. 

The  tone  and  frequency  of  the  Instrument  Is  TRULY  A  MOST 
WONDERFUL  and  perfect  reproduction  of  a  MUSICAL  WIRE- 
LESS NOTE  and  when  used  in  connection  with  a  wireless  re- 
ceiver it  would  be  most  difficult  to  distinguish  Its  rich  tone  from 
that  of  a  real  wireless  station  with  FIVE  HUNDRED  CYCLES 
in  the  primary  circuit.  One  of  the  most  commendable  features 
that  the  buzzer  possesses  Is  that  of  being  capable  of  standing  up 
under  continuous  service  WITHOUT  THE  ANNOYING  "STICK- 
ING" effect  that  has  been  so  characteristic  of  other  buzzers  that 
I  have  had  occasion  to  test.  In  conclusion  I  can'  say  that  both 
In  performance  and  appearance  the  "RADIOTONE"  Is  truly  a 
WONDERFUL  LITTLE  INSTRUMENT.  RAYMOND  FRANCIS 
YATES,  815  Niagara  Ave.,  Niagara  Falls,  N.  Y. 


I  have  thoroly  tested  your  "RADIOTONE' 
Buzzer,  which  I  received  a  few  days  ago,  and 
find  that  it  is  very  efficient  in  all  respects.  It 
is  all  that  you  claim  it  to  be.  The  tone  is  so 
soft  that  it  cannot  be  heard  unless  the  ear  is 
placed  a  few  inches  from  the  instrument.  This 
makes  it  very  desirable  for  testing  detectors.  I 
THINK  THAT  THERE  IS  NOTHING  BETTER 
FOR  LEARNING  THE  CODE,  since  the  sig- 
nals sound  just  like  a  high  power  wireless  sta- 
tion. Everyone  who  has  a  wireless  station  or 
who  wishes  to  learn  the  code  should  have  A 
"RADIOTONE."   BENNIE  GREENSTEIN, 

827-llth  Ave.,  N..  Minneapolis,  Minn. 


^^^^^^^^^^^^^^^^ 


No.  Hl<  1800 

The  "Electro"  Radiotone 

HIGH    FREQUENCY   SILENT   TEST  BUZZER 

The  RADIOTONE  is  NOT  a  mere  test  buzzer, 
it  is  infinitely  more.  Mr.  H.  Gernsback  who  de- 
signed this  instrument  labored  incessantly  to 
produce  an  instrument  which  would  imitate  the 
sound  of  a  high  power  Wireless  station  as  heard 
a  set  of  phones.  This  actually  has  been 
achieved  in  the  RADIOTONE.  This  instrument 
ives  a  wonderful  high  pitched  MUSICAL  NOTE 
a  the  receivers,  impossible  to  obtain  with  the 
ordinary  test  buzzer.  The  RADIOTONE  is  built 
along  entirely  new  lines;  it  is  NOT  an  ordinary 
buzzer,  reconstructed  in  some  manner.  The 
RADIOTONE  has  a  single  fine  steel  reed  vibrat- 
ing at  a  remarkably  high  speed,  adjusted  to  its 
most  efficient  frequency  at  the  factory.  Hard 
silver  contacts  are  used  to  make  the  instrument 
last  practically  forever. 

Yes,  the  RADIOTONE  is  SILENT.  In  fact, 
it  is  so  silent  that  you  must  place  your  ear  on 
top  of  it  to  hear  its  beautiful  musical  note. 

You  will  be  astounded  at  the  wonderfully  clear, 
500  cycle  note,  sounding  sharply  in  your  re- 
ceivers, when  operated  on  one  dry  cell.  To  learn 
the  codes,  there  is  absolutely  nothing  like  it. 
With  the  radiotone,  a  key  and  one  dry  cell  and 
ANY  telephone,  a  fine  learner's  set  is  had.  Two 
or  more  such  sets  in  series  will  afford  no  end  of 
pleasure  for  intercommunication  work.  Particu- 
larly now'  that  we  cannot  use  our  Wireless  sets, 
he  Radiotone  is  already  in  wonderful  demand. 
Ml  tlic  interesting  things  as  described  with  our 
CODOPHONE  (see  our  big  ad  on  page  353, 
this  issue),  can  be  performed  with  the  Radio- 
tone,  a  key,  a  dry  cell  and  a  phone 


Radiotone  as  described  each 


$.90 


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IMMEDIATE  SHIPMENTS 


TjaaaiiiEiiijfe^ 


I  received  your  "RADIOTONE"  on  June  20th, 
and  tested  it  thoroly,  and  found  it  has  the 
BEST  IMITATION  OF  WIRELESS  SIGNALS. 
All  Amateurs  should  purchase  one  of  these 
"RADIOTONES"  if  possible,  and  do  self-prac- 
tise during  the  war.  I  hope  all  Amateurs,  who 
purchase  one  of  these  "RADIOTONES"  will  find 
it  as  great  a  help  to  them  as  I  have. 

Yours   truly,  GEO.  TANAKA, 

AMATEUR  6  ATQ,  San  Francisco,  Cal. 


After  testing  the  "RADIOTONE"  I  am 
pleased  to  say  that  it  is  the  best  toned  buzzer 
on  the  market.  The  main  thing  is  that  IT 
DOES  NOT  STICK  as  so  many  others  do,  even 
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806  S.  Milton  Ave.,  Baltimore,  Md. 


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SPONSE to  the  opening  and  closing  of  the 
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Delaware  Co.,  DownsvilJe. 

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in  a  student's  buzzer  set,  it  comes  up  to  my 
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R.2,   Covington,  Tenn. 


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Name   

Address  

City   


September,  1917 


THE  ELECTRICAL  EXPERIMENTER 


351 


ELECTRIC    "BLOODHOUNDS"  TO 
FIND  AND  DESTROY  U-BOATS. 

(Continued  from  page  348) 

it  completes  a  circuit  thru  one  winding  on 
the  propeller  motor,  causing  the  torpedo 
to  get  under  way.  It  is  made  to  dive  at 
the  same  time  by  the  inert  action  of  the 
opposite  relay,  R.  1,  thru  whose  armature 
the  diving  plane  solenoid  is  excited ;  the 
planes  are  thus  placed  at  the  proper  angle 


Interrupter 


IVestot? 
galv  re/ay 

to  rudder  > 
•  b  Prope/ler 
cdml/nog 


nets 


t°'ff2 


Sat j 
40H 


"Induction    Balance"   Connections   In  Elec- 
tric  "Bloodhound."     A   Sensitive  Galvano- 
meter Relay  Is  Necessary. 

to  carry  the  torpedo  downward.  The  same 
action  occurs  for  steering  the  torpedo  to 
right  or  left,  the  opposite  "R"  relay  serv- 
ing to  actuate  the  proper  solenoid  to  swing 
the  rudder  to  port  or  starboard,  as  the 
case  may  be.  Of  course,  there  are  a  num- 
ber of  refinements  which  could  be  intro- 
duced such  as  interlocking  cut-outs,  semi- 
manual  control  from  the  tender,  etc.,  but 
the  basic  principles  of  such  control  are 
here  outlined. 

To  prevent  the  "bloodhound"  from  run- 
ning its  nose  dead  into  the  submersible's 
propeller  blades,  it  is  possible  to  provide 
several  means  for  overcoming  this  con- 
tingency. Suppose  for  example  that  we 
connect  a  special  relay  in  shunt  to  the  am- 
plifier secondary  circuits,  which  relay  would 
only  operate  when  the  torpedo  had  ap- 
proached within,  say,  50  feet  of  the  enemy, 
the  received  sound  wave  being  then  suffi- 
ciently strong  to  close  this  relay.  Again, 
consider  that  this  sluggish  relay  was  caused 
to  operate  a  time  limit  circuit-breaker  or 
relay,  which  could  be  set  to  open  its  sec- 
ondary control  circuit  after  a  time  period 
of  sufficient  duration  to  carry  the  torpedo 
one-third  the  length  of  the  submersible 
past  the  propellers.  Thus  it  is  seen  that 
it  is  possible  to  so  set  the  control  apparatus 
that  when  the  torpedo  has  reached  a  dis- 
tance of,  say,  50  feet  from  its  prey,  that 
the  special  relays  just  described  could  be 
caused  to  control  the  planes  and  rudders 
so  as  to  steer  the  "bloodhound"  parallel 
with  the  sub-sea  boat  for  a  distance  one- 
third  its  length ;  then  the  time  limit  relay 


Tomognef/c  stv. 


To  operators 

Te/egrapn  ty™  stfk 
s/$>na//r?a  chaser 


tvg.3 


2 


moaner co// 
^-Spr/np 


fio/d/ng 
magnet  coi/ 


Details    of   "Holding"    and  "Telegraphing" 
Electro-Magnets  of  Electric  U-boat  "Blood- 
hound." 


would  open,  the  induction  balance  apparatus 
would  be  acted  upon  by  the  metallic  hull ; 
its  galvanometer  relay  would  take  control 
of  the  rudder,  planes  and  propeller  and 
steer  the  missile  straight  for  the  enemy.  As 
soon  as  the  torpedo  hit  the  hull,  its  holding 
magnet  would  retain  it  securely  in  place 
and  the  propeller  motor  would  stop. 


The  commander  of  the  submarine  chaser 
boat  can  then  either  blow  up  the  submarine 
without  further  ado  or  he  can  pursue  the 
more  humane  mode  of  signaling  the  U-boat 
commander  to  come  up  at  once  and  sur- 
render with  the  whole  crew. 


OFFICIALS  ARREST  JOHANN 
ZENNECK. 

Acting  under  special  orders  from  the  De- 
partment of  Justice  at  Washington,  United 
States  Deputy  Marshal  Linford  Denny  re- 
cently arrested  Prof.  Johann  Zenneck,  Ger- 
man radio  expert,  and  took  him  to  Ellis 
Island,  where  he  will  be  interned  for  the 
duration  of  the  war. 


EXPERIMENTAL  CHEMISTRY. 

(Continued  from  page  333) 
Steam  is  furnished  by  boiling  water. 


H..O 

Water 


H20 
Steam 


The  gases  thus  formed,  HcO  [Steam], 
Sulfur  Dioxid  [S02]  and  Nitrogen  Per- 
oxid  [N02],  mingle  in  the  large  central 
flask,  and  combine  as  follows : 


H20     +     S02    +    N02  : 
Steam        Sulfur  Nitrogen 
Dioxid  Feroxid 


H3S04    +  NO 
Sulfuric  Nitric 
Acid  Oxid 


Nitric  Oxid  [NO]  takes  oxygen  again 
from  the  air,  forming  Nitrogen  Peroxid 
[N02],  and  once  more  passes  on  half  of  it. 
The  action  is  very  peculiar  and  continues 
so  long  as  there  is  a  supply  of  oxygen. 
Nitric  Oxid  is  therefore  called  a  carrier  of 
oxygen.  It  is  thus  seen  that  the  nitric  oxid 
[NO]  is  a  reducer,  Nitrogen  peroxid  [N02] 
an  oxidiser. 

The  Chamber  acid,  has  a  specific  gravity 
of  1.5  and  is  about  65%  acid  and  35% 
water.  This  is  strong  enough  for  the 
manufacture  of  sodium  sulfate  [Na2SO<], 
one  of  its  two  main  uses.  If  stronger,  it 
absorbs  much  nitrous  anhydrid  [N20«]. 
It  is  then  removed  from  the  chambers  and 
reservoirs,  and  evaporated  in  open  lead 
pans  till  it  has  a  specific  gravity  of  1.75. 
Stronger  than  this  it  dissolves  considerable 
lead,  and  it  is  then  evaporated  in  platinum 
crucibles  till  the  specific  gravity  is  1.83. 
This  is  about  the  commercial  strength ; 
pure  acid  being  1.854. 

The  contact  method  of  making  the  acid 
which  is  now  coming  into  considerable  use 
in  this  and  other  countries,  involves  the 
very  simple  principle  of  making  S02  into 
SO  and  leading  the  latter  into  water. 

Properties — Physical 

1.  Sulfuric  acid  is  a  thick,  oily,  and  cor- 
rosive liquid  without  color  or  odor  when 
pure.  It  usually  has  a  brown  color  due  to 
the  presence .  of  charred  organic  matter, 
such  as  straw  and  dust. 

2.  Specific  gravity  if  pure  1.854;  com- 
mercial about  1.83. 

3.  It  possesses  a  sour  taste  and  acid  re- 
action. 

4.  It  boils  at  338  degrees  C.  (about  642 
deg.  Fah.)  and  freezes  at  about  zero. 

5.  It  is  miscible  in  water,  with  which  it 
reacts  and  condenses. 

Chemical 

1.  It  reacts  with  most  metals  to  form 
sulfates ;  if  dilute,  liberates  hydrogen ;  if 
strong  sulfur  dioxid.  Its  action  takes  place 
at  a  low  temperature,  hydrogen  is  evolved, 
providing  sufficient  water  is  present  to  dis- 
solve the  metallic  sulfate  formed. 

Zn  +  H2S04  =  ZnS04  +  H2 
Fe  +   H2S04  =   FeSOi  +  H2 

Mercury  [Hg],  silver  [Ag]  and  Copper 
[Cu]  are  not  affected  by  the  action  of  cold 
[H2S04],  but  if  concentrated  acid  is  used 


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THE  ELECTRICAL  EXPERIMENTER 


September,  1917 


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and  the  temperature  raised  sufficiently, 
they  react,  reducing  part  of  the  sulfuric 
acid,  forming  sulfur  dioxid  and  water,  and 
metallic  sulfates : 

Cu  +  H2S04  =  CuS04  +  2H 
H2SOi  +  2H  =  2H20  +  SOa 

Thus  at  ordinary  temperature,  sulfuric 
acid  acts  like  hydrochloric  acid,  exchanging 
its  hydrogen  for  metals,  but  when  hot  and 
concentrated,  it  acts  also  as  an  oxidizing 
agent. 

2.  Sulfuric  acid  does  not  affect  Gold,  or 
Platinum,  and  only  hot,  concentrated,  af- 
fects Lead. 

3.  At  red  heat  it  dissociates  into  FLO 
and  Sulfur  trioxid  [S03],  and  thence  Sul- 
fur dioxid  [SO-]  and  oxygen  [O]. 

4.  It  possesses  great  affinity  for  water. 
The  fact  has  been  repeatedly  illustrated  in 

experiments  already  performed  that  sul- 
furic acid  has  a  very  strong  tendency  to 
absorb  water  and  form  compounds  with  it, 
thereby  causing  great  heat  to  be  formed  in 
this  action,  and  attention  is  called  to  the 
necessity  for  caution  in  mixing  this  acid. 
Always  pour  sulfuric  acid  in  small  quan- 
tities into  the  water,  while  stirring  the  same 
vigorously.  If  care  is  not  exercised  in 
mixing  this  acid  with  water,  the  heat  may 
crack  the  container  and  spatter  the  hot 
acid. 

The  tendency  of  sulfuric  acid  to  absorb 
water  may  be  illustrated  by  the  following 
examples : 

(a)  When  concentrated,  it  absorbs  mois- 
ture from  the  air,  and  from  gases  passing 
thru  it. 

(b)  It  is  frequently  employed  in  the  lab- 
oratory to  dry  gases,  since  it  is  not  vola- 
tile at  the  ordinary  temperature. 

(c)  Wood,  paper,  sugar,  starch,  etc.,  and 
many  organic  substances  are  blackened  by 
the  acid,  due  to  the  acid  removing  both  the 
hydrogen  and  oxygen,  forming  water,  and 
leaving  carbon. 

From  oxalic  acid  [H2C204]  or  alcohol 
[C2H60]  it  removes  hydrogen  and  oxygen, 
causes  them  to  combine  to  form  water,  and 
absorbs  the  latter. 


JLC-Oi 
C2HeO 


H.O  +  C02  +  CO 
H20  +  C2H4 


Its  action  on  the  skin,  producing  painful 
sores,  and  on  organic  matter  generally,  is 
due  to  its  affinity  for  water. 

5.  It  neutralizes  and  dissolves  bases  and 
metallic  oxids  to  form  sulfates : 

2KOH  +    H.S04  =     K»S04     +  2H20 
Ca(OH)3  +    H-SOi  =     CaS04     +  2H20 
ZnO  +    H.S04  =      ZnS04    +  H20 
Fe2Oa  +  3H2S04  —  Fe2(S04)3  +  3H20 

USES 

As  stated  under  the  history  of  this  acid, 
it  is  used  in  almost  every  art  or  trade, 
either  directly  or  indirectly.  Its  manu- 
facture is  the  king  of- industries. 

Probably  the  uses  which  would  be  of 
most  interest  to  readers  of  this  journal 
would  be  when  used  in  conjunction  with 
electricity. 

1.  In  lead  storage  batteries,  in  the 
charged  state,  a  positive  plate  of  lead  per- 
oxid  [Pb02]  and  a  negative  plate  of  finely 
divided,  lead,  are  introduced  into  sulfuric 
acid.  When  discharged,  the  surface  of 
both  plates  has  been  changed  to  lead  sul- 
fate [PbS04].  The  plates  may  be  brought 
back  to  their  original  condition  by  sending 
a  current  thru  the  battery  in  the  reverse 
direction.  Storage  battery  plates  are 
usually  made  by  two  general  methods, 
which  are  only  modifications  of  the  original 
Plante  or  Faure  process. 

The  Plante  process  includes  all  methods 
in  which  the  active  material  is  made  from 
the  plate  itself,  which  should  be  pure  soft 
lead.  There  are  numerous  methods  of 
accelerating  the  i  formation.     Usually  the 


surface  is  worked  up  mechanically  by  cut- 
ting grooves,  provided  it  has  not  been  cut 
in  this  form.  The  next  operation  is  to 
produce  the  necessary  amount  of  active 
material.  The  plates  are  frequently  per- 
mitted to  stand  in  some  corroding  solution 
of  acids  that  produce  a  thick  layer  of  lead 
sulfate  [PbSO.i],  for  a  certain  time.  The 
lead  sulfate  may  then  be  reduced  electro- 
lytically  to  lead,  or  oxidized  to  lead  peroxid 
[Pb02].  When  acids  other  than  sulfuric 
are  used,  these  must  be  thoroly  washed  out 
before  the  battery  is  ready  for  use.  For 
instance,  a  mixture  of  Nitric  and  Sulfuric 
acids  would  have  the  effect  of  producing 
a  layer  of  sulfate. 

The  theory  of  the  lead  storage  battery 
which  is  generally  accepted  is  known  as  the 
"Sulfate  theory,"  and  is  due  to  Gladstone 
and  Tribe.  Sulfuric  acid  combines  with  the 
plates  on  discharge,  and  is  set  free  on 
charge,  according  to  this  theory.  On  dis- 
charge, hydrogen  is  deposited  on  the  lead 
peroxid  which  reduces  it  to  lead  oxid 
[PbO],  which  is  changed  to  lead  sulfate 
[PbSOi],  as  represented  by  the  equation: 


Pb02  +  H2  +  H,S04 
Lead  Hydrogen  Sulfuric 
Feroxid  Acid 


PbS04  +  2H20 
Lead  Water 
Sulfate 


At  the  same  time  the  sulfate  radical  [SO] 
is  deposited  on  the  lead  plate  and  changes 
to  lead  sulfate : 

Pb     +     S04    =  PbSOi 
Lead         Sulfate  Lead 
Radical  Sulfate 

The  sum  of  these  two  equations  is  the 
total  change  in  the  storage  battery  on  dis- 
charge: 

PbOa  +  Pb  +  2H»S04  =  2PbS04  +  2H20 
Lead         Lead       Sulfuric  Lead  Water 

Peroxid  Acid  Sulfate 

When  in  the  discharged  state  both  plates 
are  covered  with  sulfate.  Upon  charging, 
the  reaction  on  the  positive  plate  is : 

PbSOi  +  S04  +  2H20  =  PbOa  +  2H2S04 
Lead        Sulfate     Water         Lead  Sulfuric 
Sulfate       Radical  Peroxid  Acid 


While  in  the  negative  plate : 


PbS04     +  H2 
Lead  Hydrogen 
Sulfate 


Pb     +  H2S04 
Lead  Sulfuric 
Acid 


The  sum  of  the  last  two  equations  repre- 
sents what  takes  place  in  the  whole  battery 

on  charging: 

2PbS04  +  2H„0  =  Pb02  +  Pb  +  2H2S04 

Lead  Water       Lead         Lead  Sulfuric 

Sulfate  Peroxid  Acid 

This  equation  is  just  the  reverse  of  the  one 
given  as  the  sum  of  the  first  two  equations 
(No.  3),  and  the  changes  taking  place  both 
on  charge  and  discharge  may  be  repre- 
sented by  the  reversible  equation  : 

Pb02  +  Pb  +  2H2S04  ^  2PbS04  +  2H20 
Lead         Lead      Sulfuric  Lead  Water 

Peroxid  Acid  Sulfate 

From  right  to  left  this  represents  the 
charge,  and  from  left  to  right  the  dis- 
charge. 

( This  use  as  regards  storage  batteries  is 
taken  from  the  manuscript  which  the 
author  has  in  preparation  on  "CHEMICAL 
ACTION  OF  STORAGE  BATTERIES.") 

2.  This  acid  is  the  basis  of  the  manu- 
facture of  most  other  acids,  and  so  of  most 
salts.  The  manufacture  of  alkalies  too,  in- 
cluding sodium  carbonat,  depends  mainly 
upon  this  acid. 

3.  Its  action  on  bones  to  make  fertilizers. 
This  action  transforms  an  insoluble  calcium 
phosfate  [Ca3(P04)2]  into  a  soluble  one 
[H4Ca(P04)2l,  thus  enabling  plants  to  ab- 
sorb the  phosfate  from  soils  on  which  fer- 

(Cont'nued  on' paae  354) 


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September,  1917 


THE   ELECTRICAL  EXPERIMENTER 


353 


1 


EXPERIMENTERS! 


The  "Electro"  Codophone 

(Patents  Pending) 

Now  that  we  are  for  the  time  being,  deprived  of  using  our 
Radio  outfits,  it  behooves  us  as  good  Americans  to  become 
proficient  in  learning  the  Wireless  as  well  as  Telegraph 
Codes.  Operators  who  know  the  Code  are,  and  will  be,  in 
ever  rising  demand.  The  Army  and  Navy  need  thousands 
of  operators  right  now. 

So  far  the  Government  has  not  been  able  to  obtain  any 
way  near  all  the  operators  it  requires.  Not  alone  does  the 
Federal  Government  call  for  thousands  and  thousands  of 
operators  for  the  army  and  navy,  but  nearly  all  of  our  many 

states  require  operators  for  the 
militia.  Here  is  the  great  opportun- 
ity of  a  life  time  for  you. 

Would  you  rather  fight  in  the 
trenches,  or  punch  the  key  behind 
the  lines?  Either  way  you  benefit 
your  country.  Which  do  you  prefer? 
And  it  is  SO  easy  to  become  an  oper- 
ator. You  do  not  necessarily  require 
a  teacher,  nor  do  you  have  to  go  to 
a  school  to  learn.  ■  30  days  of  intel- 
ligent study  will  make  you  proficient. 
Can  you  qualify  NOW?  Are  you 
proficient?  Can  you  send  and  receive 
when  your  country  calls  you  f 

THE  "ELECTRO"  CODOPHONE 

(Patents  Pending) 
which  we  present  herewith  is  the 
outcome  of  several  months  of  intense 
study  and  experimentation  of  our 
Mr.  H.  Gernsback.  It  supersedes  our 
former  Radiotone  Codegraph,  which 
comprised  a  Radiotone  silent  Buzzer, 
a  loud  talking  telephone  receiver  and 

a  key.  As  in  all  of  his  work  Mr.  Gernsback  strives  for  simplicity, 
he  combined  the  three  above  mentioned  instruments  with  one  stroke  into 
ONE  single  instrument.  He  combined  the  Radiotone  Buzzer  and  the  loud 
talking  receiver  into  a  single  unit,  not  only  mechanically,  but  electrically 
as  well.  This  involves  an  entirely  new  principle,  never  before  attempted, 
and  on  which  basic  patents  are  now  pending. 

What  this  remarkable  instrument  is  and  does. 
The  "Electro"  Codophone  is  positively  the  only  instrument  made  that 
will  imitate  a  500  cycle  note  exactly  as  heard  in  a  Wireless  receiver,  so 


closely  and  so  wonderfully  clear,  that  Radio  operators  gasp  in  astonish- 
ment when  they  first  hear  it.  And  you  need  no  receivers  over  the  ears  to 
hear  the  imitation  singing  spark,  which  sounds  for  all  the  world  like  a 
high-pitched  distant  powerful  Radio  Station.  No,  the  loud-talking  receiver 
equipped  with  a  horn,  talks  so  loud  that  you  can  hear  the  sound  all  over 
the  room,  even  if  there  is  a  lot  of  other  noise. 

THAT'S  NOT  ALL.  By  lessening  or  tightening  the  receiver  cap,  a  tone 
from  the  lowest,  softest  quality,  up  to  the  loudest  and  highest  screaming 
sound  can  lie  had  in  a  few  seconds. 

FURTHERMORE,  this  jack-of-all-trades  marvel,  can  be  changed  in- 
stantly into  our  famous  silent  Radiotone  test  buzzer,  simply  by  replacing 
the  metal  diaphragm  with  a  felt  disc,  which  we  furnish  with  every  instru- 
ment. 

FOR  INTERCOMMUNICATION.  Using  two  dry  cells  for  each  instru- 
ment, two  Codophones  when  connected  with  one  wire  and  return  ground, 
can  be  used  for  intercommunication  between  two  houses  one-half  mile 
apart.  Any  one  station  can  call  the  other,  no  switches,  no  other  appliance; 
required.    No  call  bell  either,  the  loud-talking  phone  takes  care  of  this. 

AS  AN  ARMY  TYPE  BUZZER.  Last,  but  not  least,  two  Codophones 
with  two  75  ohm  receivers  can  be  used  to  converse  over  miles  of  fine  (No. 

3(i  B  &  S  Wire),  so  fine  that  no  one 
-^T*.     ^  y-^  can  see  the  wire.    Or  you  can  use  a 

^TJ  M  long  metallic  fence  and  the  ground, 

.^^fc  fj  or  you  can  communicate  over  your 

I    110  volt  line  up  to  several  miles,  us- 

JL  9  ^— —  ing  no  wires,  only  the  ground. 

Full  directions  how  to  do  all  this 
furnished  with  each  instrument. 

One  outfit  alone  replaces  the  old- 
fashioned  learner's  telegraph  set, 
consisting  of  key  and  sounder,  which 
is  all  right  to  learn  the  telegraph 
code  but  not  the  wireless  codes. 

The  "Electro"  Codophone  is  a 
handsome,  well  made  instrument, 
fool  proof,  and  built  for  hard  work. 
Contacts  are  of  hard  silver  y3  inch 
in  diameter,  that  will  outlast  the  in- 
strument. Base  and  housing  is  of 
metal  throughout,  horn  and  key 
lever  nickel  plated  and  buffed.  Three 
new  style  metal  binding  posts  are 
furnished. 

There  is  also  a  neat  code  chart  and 
full  directions  enabling  any  intelli- 
gent young  man  or  girl  to  learn  the  codes  within  30  days,  practising  one- 
half  hour  a  day. 

Sizes:   6%    x  3  x  2%".     Shipping  weight,   4  lbs. 
The  "Electro"  Codophone  as  described,  complete 

Money  refunded  if  instrument  is  not  as  represented  or  does  not  come  up 
fully  to  expectation. 

Ready  for  delivery  Aug.  2oth.  There  will  be  an  enormous  demand  for 
this  new  marvel — place  your  order  now.  All  orders  filled  in  rotation. 
Better  order  two  instruments  today. 


$1.35 


THE    "ELECTRO"  SPINTHARISCOPE 


MAKING  RADIUM 
VISIBLE 


As  usual  we  lead — others  follow.  Now  the  Spinthari- 
scope, first  to  be  introduced  to  the  American  public  by 
us.  The  Spinthariscope  was  originated  by  the  famous 
English  Radium  expert,  Sir  William  Crookes.  Everyone 
knows  that  Radium  gives  off  a  tremendous  amount  of 
energy  which  goes  on  for  several  thousand  years,  with 
undiminished  force. 

Radium  gives  off  a  number  of  rays  of  which  the 
Alpha  rays  are  known  chiefly  for  their  great  power. 

These  electric  rays  are  invisible  to  the  naked  eye,  the 
same  as  are  X-rays.  But  if  we  take  a  small  amount  of 
Radium  and  place  it  in  front  of  a  zinc-sulfide  screen, 
the  latter  light;  up.  If  the  radium  speck  is  arranged 
suitably  the  Alpha  rays  will  bombard  the  zinc  sulfide 
with  a  veritable  hail  of  electrons  and  the  screen  begins 
to  scintillate  like  Fourth  of  July  fireworks. 

This  is  the  principle  of  the  Spinthariscope,  which  we  present  herewith. 
It  is  a  little  instrument  made  of  two  neatly  nickeled  metal  tubes,  one 

You  owe  it  to  yourself  to  own  one.  It  is  small  enough  to  be  put  into  your  vest-pocket,  and  interesting  enough  to  show  it  to  all  of  your  friends. 
It  will  continue  to  operate  af*cr  you  are  dead  2500  years!    We  guarantee  the  instrument  to  be  genuine  and  to  contain  a  mimite  quantity  of  real 

Radium  salts.    "Electro"  Spinthariscope,  in  neat  box  and  directions  for  use,  as  described  

Sent   Prepaid.     IMMEDIATE  SHIPMENTS. 


telescoping  into  the  other.  The  top  tube  has  a  powerful 
lens.  The  bottom  contains  the  zinc-sulfide  screen  and 
a  minute  quantity  of  REAL  RADIUM,  too  small  to  do 
any  harm.  The  instrument  can  only  be  used  in  the 
dark.  After  the  top  tube  with  the  lens  has  been  ad- 
justed to  the  right  focus,  we  observe  a  vividly  illumi- 
nated green  background,  glowing  in  a  soft  light.  As 
the  eye  becomes  accustomed  to  it,  we  begin  to  see  the 
ELECTRONIC  BOMBARDMENT  of  the  Alpha  rays  from 
the  Radium.  It  looks  exactly  like  tiny  fireflies  flashing 
off  and  on  in  the  dark  night.  The  more  we  look  the 
better  we  see  the  miniature  fireworks.  We  are  now  in 
the  presence  of  the  most  marvelous  substance  man  ever 
knew,  RADIUM  and  its  uncanny  forces — Radium,  which 
some  day  will  turn  the  world  upside  down. 

The  Spinthariscope  up  to  now  sold  from  $10.00  up- 
wards, but  by  greatly  simplifying  it  the  cost  has  been  brought  down  by 
us  to  such  a  nominal  figure,  that  no  one  can  afford  to  be  without  thn 
most  important  and  marvelous  instrument. 


$1.00 


LABORATORY  OUTFIT! 


We  have  spent  considerable  time  to  com- 
bine just  £uch  a  practical '  outfit  and  pre- 
sent it  herewith  to  our  friends. 

The  outfit  is  complete  as  per  illustration 
and  consists  of : 

1  Stand,  made  of  well  quartered  oak, 
varnished  three  times,  so  as  to  be  acid  proof 
and  grooved  on  top  and  bottom,  so  that  it 
■will  not  warp  in  getting  wet.  Size  53A 
inches  high  by  11  Mj  inches  long. 

1  Glass  Spirit  Lamp.  Size  3%  inches  by 
2  inches.  Uses  wood  alcohol  and  is  in- 
valuable to  the  experimenter.  Besides  be- 
ing used  to  heat  test-tubes  contents  as  per 
illustration,  it  can  be  used  to  bend  glass 
rods  and  tubings,  to  solder  wire,  etc. 

1  Glass  Filter  Funnel.  This  funnel  is 
made  of  heavy  glass  that  wall  not  break 
easily.  It  fits  accurately  in  the  hole  on  top 
of  the  Filter  stand  and  is  provided  with  a 
thick  rim  on  the  outlet,  so  that  a  rubber 
hose  can  be  attached  to  it,'  without  slipping 
off. 

1  Glass  Rod,  to  be  used  in  stirring  and 

mixing. 

10  Test  Tubes,  made  from  the  best  im- 
ported glass.  A  iipw  feature  of  some  of 
the  test  tubes  is  that  they  have  a  flat  bot- 
tom and  therefore  can  be  placed  on  any 
table  if  desired,  needing  no  special  stand. 

1  Roll  of  Copper  Clad  Steel  Wire.  This 
wire  is  to  be  used  to  make  a  number  of  use- 
ful articles  as   shown  in   the  illustration. 


such  as  test-tube  holders,  tripods  to  support 
retorts,  etc.  We  furnish  a  blue  print  with 
the  outfit,  showing  how  to  make  all  these 
wire  articles. 

Now  this  whole  outfit  as  described  <M  0C 
costs  you  only    <pi.£.J 

Postage  extra.    Shipping  weight.  4  lbs. 
Order  one  today,  even  if  you  don't  need 
it  now. 

"The  Livest  Catalog  in  America" 

Our  big,  new  electrical  cyclopedia.  No.  18 
is  waiting  for  you.  Positively  the  most  com- 
plete Wireless  and  electrical  catalog  in  print 
today.  200  Big  Pages.  600  illustrations.  500 
instruments  and  apparatus,  etc.  Big  "Trea- 
tise on  Wireless  Telegraphy."  20  FREE 
coupons  for  our  160-page  FREE  Wireless 
Course  in  20  lessons.  FREE  Cyclo- 
pedia  No.  18  measures  7x5%".  I 
Weight  V2  lb.    Beautiful  stiff  covers.    I  : 

Now  before  you  turn  this  page  write  HH 
your  name  and  address  on  margin  be- 
low,  cut  or  tear  out,   enclose  6  cts. 
stamps  to  cover  mail  charges,  and  the 
Cyclopedia  is  yours  by  return  mail. 

THE  ELECTRO  IMPORTING  CO. 
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1119 


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354 


THE  ELECTRICAL  EXPERIMENTER 


September,  1917 


EXPERIMENTAL  CHEMISTRY. 

(Continued  from  page  352) 
tilizers  is  used.  Rain  dissolves  the  soluble 
superphosfate,  as  H4Ca(P04)2  is  called, 
and  it  is  carried  to  the  roots  of  plants  and 
thence  circulated  by  the  sap  and  deposited 
in  the  fruiting  parts  of  the  plant.  Food 
plants,  like  the  cereals,  will  not  come  to 
maturity  or  fruitage  without  phosphorous 
in  this  form.  In  this  way  our  daily  bread 
is  in  part  supplied  by  sulfuric  acid. 

4.  Another  important  use  is  in  the  prep- 
aration of  sodium  sulfate  [NazSCX],  from 
sodium  chlorid  as  a  step  in  the  sodium  car- 
bonat  [NajC03]  manufacture.  Sodium 
carbonat  forms  the  basis  of  such  industries 
as  the  manufacture  of  glass,  soap,  saleratus, 
baking  powders  and  most  alkalies. 

5.  Besides  these  uses,  sulfates  are 
formed  by  action  of  the  acid  on  metals  or 
their  salts. 

6.  Directly  or  indirectly  H2SO«  is  em- 
ployed in  the  preparation  of  compounds 
for  bleaching,  dyeing,  printing,  electro- 
plating, telegraphy,  galvanizing  iron  plates 
and   wire,   cleaning  metals,   making  shoe 


blacking,    glucose,    mineral    waters,  soda 
waters,    ether,   nitroglycerine,  gun-cotton, 
vegetable  parchment,  celluloid,  etc. 
EXPERIMENT  NO.  89 

Preparation  from  H2SO4,  Cu,  HN03,  and 
H20. 

CAUTION.— This  experiment  should  be 
performed  in  a  well  ventilated  room,  or 
under  a  hood. 

The  author  has  found  this  experiment, 
when  carefully  made,  an  excellent  and  very 
interesting  one. 

As  this  experiment  requires  several  of 
each  piece  of  apparatus,  many  readers  will 
not  want  to  go  to  the  expense  of  purchas- 
ing the  additional  pieces  required.  If  this 
be  the  case,  it  might  be  well  to  try  and 
borrow  these  from  a  friendly  druggist,  if 
he  has  them,  or,  if  you  have  some  friends 
who  are  interested  in  chemistry,  who  have 
the  pieces,  you  might  be  able  to  work  this 
experiment  with  them.  Again,  if  several 
get  together  and  each  pay  for  the  additional 
apparatus,  it  may  be  performed,  by  this 
method,  at  the  same  time,  it  will  undoubted- 
ly create  sufficient  interest,  for  the  others 


to  start  experiments  of  their  own,  and  in 
this  way,  each  experiment  could  be  per- 
formed by  the  several  people  at  the  same 
time. 

Have  four  Erlenmeyer  or  Florence  flasks, 
three  of  which  are  plain,  thin  glass,  and  of 
125  to  250  cc.  capacity;  the  other  of  250 
cc. ;  thick  glass  and  side  neck  (not  given  in 
the  illustration)  with  a  rubber  stopper  to 
accommodate  the  numerous  delivery  tubes. 
The  three  small  flasks  have  2-hole  rubber 
stoppers,  each  carrying  a  thistle  and  a  right 
angle  delivery  tube,  and  each  is  set  on  an 
iron  tripod,  or  ring  stand  with  an  asbestos 
pad.  The  delivery  tubes  lead  into  the  large 
flask,  and  should  extend  at  least  two-thirds 
of  the  distance  to  the  bottom.  The  fourth 
hole  in  the  stopper  of  the  receiving  flask 
contains  a  short  tube  with  a  rubber  connec- 
tor to  another  tube  used  as  a  mouthpiece, 
for  blowing  in  air. 

Pour  into  one  of  the  small  flasks,  25  cc. 
of  water,  into  each  of  the  other  two  not 
over  10  grams  of  copper  scraps.  Adjust 
the  apparatus  and  then  pour  into  one  of  the 
flasks  containing  copper  25  cc.  of  sulfuric 
acid.  Heat  the  flask  containing  water,  and 
also  the  one  containing  copper  and  Sul- 
furic acid.  As  soon  as  the  water  boils  and 
action  begins  in  the  other  heated  flask, 
pour  into  the  third  flask  containing  copper 
alone,  22  cc.  of  nitric  acid  diluted  with  half 
water.  Apply  gentle  heat  to  this  last  one, 
if  necessary.  Remove  the  heat  for  a  min- 
ute from  the  other  two  flasks.  In  all  cases 
heat  must  be  carefully  regulated.  The 
fumes  in  the  large  flask  should  become 
white,  then  red,  then  white  again.  When 
they  become  white,  blow  into  the  receiver 
thru  the  mouthpiece,  and  if  necessary  to 
change  them  to  red,  heat  the  flask  contain- 
ing nitric  acid,  or  even  put  in  more  acid. 
Bear  in  mind  that  sulfuric  acid  can  only 
be  made  when  red  N02  fumes  are  present. 
Hence  keep  alternating  the  heat  for  the 
three  flasks  and  blowing  into  the  receiver. 
The  breath  furnishes  oxygen,  which  com- 
bines with  the  nitrogen  dioxid  [NO]  from 
the  nitric  acid  to  form  nitrogen  tetroxid 
[N02],  which  latter  gives  up  half  of  its 
oxygen  to  the  sulfurous  acid  [H2SOs]  to 
form  sulfuric  acid  [H2S04]. 

After  continuing  the  process  twenty  min- 
utes, clean  the  entire  apparatus,  save  the 
acid  made,  and  wash  and  save  any  remain- 
ing copper. 

EXPERIMENT  NO.  90 

Made  from  Sulfur,  Nitric  acid,  Water 
and  Air. 

The  reactions  in  making  sulfuric  acid, 
and  its  preparation  on  a  minute  scale,  may 
be  shown  by  the  following  experiment. 

Burn  in  a  wide  mouth  bottle  of  250  cc. 
capacity  a  piece  of  sulfur  the  size  of  a 
split  pea,  placed  in  a  combustion  cup  and 
set  on  fire  in  the  usual  way,  as  shown  by 
Fig.  81.  Keep  the  receiver  nearly  covered 
with  a  glass  plate.  When  combustion  stops, 
take  out  the  sulfur,  keeping  the  bottle  still 
covered.  Fasten  a  small  tuft  of  cotton 
to  a  splint  and  dip  it  into  a  little  Nitric 
acid  in  a  dish.  Or  fold  a  piece  of  old 
book  or  newspaper  about  5x8  inches,  with 
folds  about  ]/i  inch  in  width,  and  immerse 
about  an  inch  of  this  folded  paper  in  5  cc. 
of  Nitric  acid  so  as  to  saturate  it,  but  avoid 
dripping.  Take  the  cover  momentarily 
from  the  wide  mouth  bottle  and  bring  the 
acidified  cotton  or  paper  in  contact  with 
the  fumes,  alternately  raising  and  lowering 
it ;  then  hang  it  on  the  inside  of  the  bottle 
and  cover  it  at  once,  letting  it  stand  for 
five  minutes  or  more,  as  shown  by  Fig.  82. 
Now  boil  10  cc.  of  water  in  a  tube,  and, 
having  taken  out  the  acidified  cotton  or 
paper,  pour  it  while  hot  into  the  bottle. 
Cover  the  latter  with  a  stopper  or  the  hand 
and  shake  it  vigorously  a  minute  or  two, 
(Continued  on  page  358) 


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THE  ELECTRICAL  EXPERIMENTER 


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MANUFACTURING  MAGNETISM. 

{Continued  from  page  313) 

thing  left  to  see  is  why  the  atoms,  or 
elemental  magnets,  act  like  gyroscopes  and 
line  up  when  the  bar  is  rotated.  Let  us 
remember  that  one  of  the  assumptions  of 
the  modern  electron  theory  of  matter  is 
that  every  atom  is  believed  to  be  composed 
of  a  positive  nucleus  or  center,  about  which 
the  negative  particles  or  electrons  rotate 
at  high  velocity,  as  in  Fig.  I.  It  is  not  hard 
to  see  that  each  atom  therefore  acts  as  a 
gyroscope  (called  in  this  case  a  gyrostat). 
Also  the  revolving  electron  constitutes  a 
minute  electric  current  flowing  in  a  circle 
about  the  nucleus,  and  like  all  electric  cur- 
rents flowing  in  such  a  manner,  it  has  a 
magnetic  field  directed  thru  its  orbit  in  the 
direction  of  the  vertical  arrow.  Ordinarily, 
when  a  piece  of  steel  is  strongly  magnetized 
by  stroking  it  with  another  magnet,  it 
seems  that  all  or  a  majority  of  these  little 
electro-magnetic  systems  are  forced  about 
until  they  point  in  the  same  direction,  and 
the  magnetism  of  all  of  these  added  to- 
gether constitutes  the  magnetism  of  the 
whole  body. 

This  gives  us  a  theory  of  magnetism 
which  is  quite  an  advance  over  the  old  so- 
called  molecular  theory  of  magnetism  which 
asserted  that  no  matter  how  much  a  mag- 
net be  subdivided  the  parts  would  always 
be  little  magnets  just  like  the  first.  The 
advance  which  has  been  made  in  the  theory 
is  shown  in  Fig.  II. 

By  rotating  a  bar  of  iron  or  steel  about 
a  longitudinal  axis  these  atomic  gyrostats 
line  up  like  so  many  spinning  tops  and  the 
bar  is  magnetized.  So  far  it  has  not  been 
possible  to  overcome  the  internal  force  of 
the  iron  sufficiently  to  magnetize  the  bar 
except  very  weakly,  but  this  has  been  done, 
and  repeated  experiments  all  agree,  show- 
ing that  a  new  method  of  producing  mag- 
netization has  really  been  obtained,  and 
showing  that  the  assumptions  concerning 
the  atom  were  true. 

This  method  of  magnetization  suggests 
a  new  explanation  of  the  earth's  magne- 
tism, as  being  due,  in  part  at  least,  to  the 
rotation  of  the  earth.  Such  a  calculation, 
however,  only  accounts  for  a  very  small 
part  of  the  earth's  magnetism,  and  we  are 
led  to  conclude  that  either  the  magnetism 
of  the  earth  is  due  in  very  small  part  to 
rotation,  or  else  our  knowledge  of  the 
physical  state  of  the  molten  interior  of  the 
earth  may  be  too  little  upon  which  to 
justify  in  any  way  a  calculation  based  upon 
the  observation  of  a  solid  bar  of  iron. 

About  a  year  ago  a  somewhat  incautious 
newspaper  reporter  sent  word  to  his  paper 
that  a  new  metal  had  been  discovered  with 
about  a  hundred  times  the  magnetic  per- 
meability of  iron,  and  that  soon  a  small 
electric  power  plant  could  be  carried  in  the 
pocket.  Although  the  latter  statement  may 
not  be  so  far  from  the  truth,  the  former, 
like  the  alchemists  of  old,  is  a  long,  long 
way  from  being  realized.  In  fact,  it  was 
a  mere  rumor  suggested  by  some  research 
work  of  Trygve  Yensen  (at  the  University 
of  Illinois),  who  was  studying  an  iron- 
cobalt  alloy  (Fe2Co).  This  work,  tho  not 
at  all  startling,  is  nevertheless  of  no  little 
interest  to  both  scientists  and  engineers 
alike,  because  it  deals  with  a  metal  alloy 
having  a  higher  permeability  than  iron  it- 
self. This  alloy  was  really  discovered  by 
Weiss  of  Zurich  in  1912,  who  found  it  had 
a  saturation  value  of  magnetization  ten 
per  cent,  higher  than  that  of  pure  iron.  Up 
to  this  time  it  had  been  supposed  that  such 
a  metal  was  a  practical  impossibility.  Thru- 
out  the  usual  range  of  field  strength  the 
permeability  is  twenty-five  per  cent,  higher. 
If  the  alloy  proves  itself  co-nmercially  prac- 


tical this  would  mean  a  twenty-five  per 
cent,  reduction  in  size  and  amount  of  wire 
on  dynamos,  motors,  transformers  and 
other  such  pieces  of  apparatus. 

Heusler  probably  paved  the  way  for  the 
discovery  of  this  alloy  when  he  found  the 
famous  alloys  which  bear  his  own  name  in 
1903.  These  alloys  composed  of  manga- 
nese, aluminum  and  copper  ;  and  of  manga- 
nese, aluminum  and  zinc,  are  themselves 
strongly  magnetic  tho  the  elements  com- 
posing them  are  non-magnetic. 

The  two  facts,  that  a  magnetic  alloy  can 
be  made  from  non-magnetic  metals,  and 
that  an  alloy  of  higher  permeability  than 
any  known  can  be  made  of  iron  and  cobalt, 
tho  they  seem  at  first  in  contradiction  to 
ordinary  law,  are  in  reality  quite  in  har- 
mony with  recent  theory.  If  the  atom  con- 
sists of  a  nucleus  about  which  a  number 
of  electrons  revolve,  and  if  all  the  electrons 
do  not  revolve  in  the  same  plane  or  same 
direction  the  magnetic  effect  of  the  atom 
may  be  anything  from  maximum  to  zero, 
depending  on  how  much  the  revolving  elec- 
trons tend  to  neutralize  each  other.  Figs. 
Ill  and  IV  represent  simple  conditions 
showing  atoms  with  two  electrons  having 
maximum  and  minimum  magnetic  strength. 

When  a  number  of  neutral  atoms  of  non- 
magnetic elements  enter  into  a  new  rela- 
tion, as  in  the  case  of  the  Heusler  alloys, 
then  it  seems  probable  that  a  change  takes 
place  so  that  the  electronic  orbits  shift, 
and  if  the  electrons  no  longer  oppose  each 
other  the  neutral  atom  then  becomes  mag- 
netic. 

Such  a  theory  suggests  that  alloys  with 
a  still  greater  permeability  than  the  iron- 
cobalt  alloy  just  mentioned,  will  be  found 
at  some  future  time. 


THE  MARVELS  OF  RADIO-AC- 
TIVITY. 

(Continued  from  page  303) 
Sir  William  Ramsay,  in  his  last  article, 
penned  just  before  his  death,  said: 

"Radium  has  been  prepared  in  the  state 
of  a  metal ;  it  is  white,  hard,  and  is  soon 
attacked  by  the  air  and  the  moistness  of 
the  atmosphere,  and  turns  into  a  white 
powder — the  oxid.     (Radium   metal  was 


Radiograph  of  Several  Objects   Made  With 
2  Grams  of  Uranyl  Chlorid  in  Thirty  Hours 
By  the  Author. 

first  produced  in  1910  by  Madame  Curie 
and  Dr.  Debierne,  by  the  electrolysis  of 
the  chlorid  into  a  mercury  cathode,  the 
mercury  being  subsequently  volatilized. 
See  the  Comptes  Rendus  de  L'Acadamie 
des  Sciences,  vol.  151,  page  523,  1910.) 

"The  gas  from  radium  changes  quickly 
into  a  solid  metal  which  Soddy  and  Ruth- 
erford called  'radium-A' ;  it  in  turn  changes 
still  more  quickly  into  a  second,  termed 
'radium-B' ;  from  it  a  third,  fourth  and 
fifth  successively  develop,  which  they 
named  'radium-C,'  'D'  and  'E,'  respectively; 
'E'  changes  into  'F,'  and  that  turned  out 
to  be  the  same  as  the  Curies'  'polonium.' 

"During  each  of  these  changes,  a  rela- 


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THE  ELECTRICAL  EXPERIMENTER 


September,  1917 


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See  page  359 


tively  enormous  amount  of  heat  is  given 
off;  now,  heat  is  a  form  of  energy;  and 
Rutherford  and  Soddy  ascribed  the  suc- 
cessive changes  to  what  they  called  the 
'degradation'  of  the  radium  and  its  prod- 
ucts, that  is  to  radium  changing  into  an- 
other element,  namely  the  gas  termed  by 
Rutherford  'emanation'  but  now  known  as 
'niton.' 

"The  change  of  radium  into  niton  is 
accompanied  by  the  emission  of  'alpha 
rays,'  one  of  the  kinds  observed  by  Becque- 
rel  to  be  emitted  from  uranium.  When 
radium-A  is  formed  by  the  degradation  of 
niton,  alpha  rays  are  also  expelled ;  radi- 
um-A changes  into  radium-B,  however, 
with  the  loss  of  no  alpha-rays,  but  only 
the  beta-rays ;  and  beta-rays  were  shown, 
later  on,  to  be  identical  with  electrons. 
What  are  alpha  rays  ? 

"The  present  writer  (Sir  William  Ram- 
say), along  with  Mr.  Soddy,  separated  the 
niton  from  a  comparatively  large  quantity 
of  radium.  It  had  all  the  properties  of  a 
gas ;  it  expanded  by  heat,  and  altered  its 
volume  under  pressure,  exactly  like  other 
gases,  such  as  oxygen  and  hydrogen.  But 
one  of  its  properties  was  almost  miracu- 
lous ;  on  standing,  the  niton  disappeared 
slowly,  and  its  place  was  taken  by  another 
gas  called  'helium,'  discovered  by  the  writer 
in  1895. 

"Such  a  phenomenon  was  at  that  time 
new  to  chemists  ;  it  implied  the  'transmuta- 
tion' of  one  element  into  another.  It  is 
true  that,  unlike  the  attempts  of  the  old 
alchemists  to  transmute  the  'baser  metals' 
(lead,  silver,  etc.)  into  gold,  this  change 
took  place  spontaneously ;  it  could  not  be 
controlled ;  still  it  was  no  less  revolution- 
ary and  striking.  One  element  may  change 
into  another,  for  there  is  no  denying  that 
both  radium  and  its  product  helium  are  in 
the  ordinary  sense  of  the  word  elements. 
Some  years  later,  the  present  writer,  work- 
ing with  Gray,  made  a  balance  so  sensi- 
tive that  by  its  aid  the  weight  of  a  quan- 
tity of  niton  so  small  that  it  would  just 
fill  a  glass  tube  no  larger  or  thicker  than 
a  very  fine  needle  was  determined ;  and 
also  a  much  smaller  weight,  that  of  the 
helium,  produced  by  the  disintegration  of 
the  niton. 

"By  an  extremely  clever  set  of  experi- 
ments, Rutherford  actually  counted  the 
number  of  atoms  of  helium  shot  off  from 
radium-C  in  a  given  time;  and  he  proved 
that  alpha  rays  are  nothing  but  a  stream 
of  helium  atoms  in  enormously  rapid  mo- 
tion, poured  out  from  radium  and  some 
of  its  products  of  disintegration.  This 
stream  goes  on  as  long  as  there  is  any  of 
the  emitting  substance  left ;  each  atom  of 
radium,  for  example,  loses  an  atom  of 
helium,  and  forms  a  new  element  niton. 

"But  the  change  of  one  element  into 
another  is  not  always  accompanied  by  the 
emission  of  an  atom  of  helium  ;  sometimes, 
as  when  radium-A  changes  into  radium-B, 
an  electron  is  lost  instead,  and  an  electron 
is  nothing  but  an  atom  of  negative  elec- 
tricity; nevertheless,  radium-A  is  just  as 
different  from  radium-B  as  radium  is  from 
niton ;  all  four  are  different  kinds  of  mat- 
ter, as  unlike  as  iron  is  to  silver. 

"Are  elements  compounds?  Yes,  in  a 
sense ;  but  they  are  very  stable  compounds, 
much  more  stable  than  ordinary  com- 
pounds such  as  water,  or  oxid  of  iron ; 
when  they  decompose,  one  of  their  prod- 
ucts appears  to  be  always  helium ;  and 
their  decomposition  is  in  all  the  cases 
which  have  been  followed  accompanied  by 
the  escape  of  a  prodigious  amount  of 
heat ;  far  more,  regard  being  paid  to  the 
amount  of  substance  changing,  than  any 
ordinary  heat  change. 

"For  example,  an  Atlantic  liner  gains 
the  power  necessary  for  crossing  the  ocean 
from  the  burning  of  coal,  and  the  heat 
produced  by  its  combustion.    It  is  not  diffi- 


cult to  calculate  that  if  the  energy  of  a 
few  ounces  of  radium  could  be  utilized 
(for  it  comes  off  far  too  slowly  to  be  made 
use  of — it  takes  thousands  of  years)  it 
would  give  all  the  power  and  more,  than 
the  coal  carried  in  her  bunkers.  We  can 
control  the  combustion  of  coal ;  we  cannot 
alter  the  rate  of  change  of  radium. 

"Radium  is  a  very  rare  substance ;  the 
ore  from  which  it  is  extracted,  pitch- 
blende, is  not  common  ;  good  ore  contains 
one-tenth  of  its  weight  of  real  oxid  .of 
uranium  ;  and  of  such  ore,  less  than  one- 
ten-millionth  is  radium ;  moreover,  the  cost 
of  extraction  is  considerable.  Up  to  now, 
its  chief  use  has  been  in  medicine." 

(To  be  continued) 


SELENIUM  CELL  DESIGN  AND 
CONSTRUCTION. 

(Continued  from  page  332) 

or  brass  plate  and  a  transparent  sheet  of 
gold  foil  on  the  other  side.  To  construct 
the  cell  a  sheet  of  copper  or  brass  of  the 
desired  size  is  covered  with  a  thin  film  of 
selenium  and  while  the  same  is  in  a  molten 
state,  a  plate  of  glass  is  placed  on  it  and 
a  slight  pressure  applied.  When  the  selen- 
ium has  cooled  and  crystallized  the  glass 
is  removed  and  a  sheet  of  transparent 
gold  foil  is  placed  over  the  selenium.  The 
cell  is  now  ready  for  annealing.  In  anneal- 
ing, a  similar  piece  of  copper,  coated  with 
selenium,  may  be  placed  alongside  of  the 
cell  to  indicate  if  the  temperature  is  too 
great  and  as  a  check  on  the  condition  of 
the  cell.  These  cells  have  been  made  with 
a  ratio  as  high  as  330  to  1 ;  the  resist- 
ance depends  upon  the  thickness  of  the 
film,  and  the  thinner  this  is  the  lower  the 
resistance. 

It  should  be  clearly  understood  that  a 
selenium  cell  requires  some  care  to  keen 
it  in  good  condition.  It  should  be  kept 
in  the  dark  when  not  in  use  and  will  re- 
tain its  sensitiveness  longer  if  exposed  to 
light  every  day  or  so.  After  some  time 
the  dark  resistance  of  the  cell  will  de- 
crease, and  when  abnormally  low  may  be 
returned  to  its  original  value  by  subject- 
ing the  cell  to  alternating  current  till  the 
resistance  is  regained.  If  exposed  to  a 
bright  light  for  long  lengths  of  time  the 
cell  will  become  fatigued  and  lose  much 
of  its  sensitiveness. 


A  FEW  DONT'S. 

Don't  leave  the  cell  in  the  dark  for  weeks 
at  a  time. 

Don't  be  afraid  of  allowing  the  cell  to 
anneal  for  several  hours,  the  longer  the 
better. 

Don't  use  a  Bunsen  burner  for  anneal- 
ing; use  an  alcohol  lamp  that  is  large 
enough  so  that  one  filling  lasts  for  five 
hours. 

Don't  use  commercial  selenium.  Get  the 
chemically  pure  grade  from  a  reliable  chem- 
ical supply  house. 

Don't  keep  the  cell  in  the  light  too  long. 

And  above  all,  don't  get  impatient  or 
disgusted  if  the  first  four  or  five  cells 
you  make  fail  to  work.  It  takes  patience, 
patience  and  more  patience,  but  persever- 
ance overcomes  all  obstacles. 


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THE  ELECTRICAL  EXPERIMENTER 


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September,  1917 

EXPERIMENTAL  CHEMISTRY. 

(Continued  from  page  354)' 

being  very  careful  not  to  get  any  acid  on 
the  clothing,  as  it  quickly  oxidizes  and  re- 
moves the  color. 

The  acid  prepared  by  this  method  will  be 
very  weak,  but  should  at  least  give  the 
barium  chlorid  and  litmus  tests. 

EXPERIMENT  NO.  91 

To  ascertain  whether  we  actually  have 
sulfuric  acid,  it  will  be  necessary  to  make 
tests  for  the  positive  and  negative  parts,  in 
other  words,  to  test  for  hydrogen  and  then 
for  the  sulfate  radical  [SO4].  Take  some 
of  the  acid  made  by  either  process  above 
and  test  it  with  blue  litmus  paper. 

To  show  that  sulfate  is  present,  take 
about  10  cc.  of  a  solution  of  barium  chlorid 
[BaCL>]  or  barium  nitrat  [Ba(NOs)2]  and 
pour  a  few  drops  of  the  liquid  you  prepared 
or  which  you  wish  to  test,  into  it.  Observe 
the  color  of  the  precipitat  formed,  and  note 
results. 

Keep  the  precipitat  and  add  to  it  10  cc.  of 
dilute  hydrochloric  acid,  made  by  mixing 
one  volume  of  the  ordinary  acid  with  three 
or  four  parts  of  water.  Shake  the  mixture 
well  and  see  whether  the  precipitat  dis- 
solves. If  it  does  it  shows  that  you  do  not 
have  sulfate  ions  or  radicals  present,  and 
the  acid  is  not  sulfuric.  But  if  the  precipi- 
tat does  not  dissolve,  it  is  a  sulfate,  for 
any  salt  of  barium  would  have  dissolved  in 
dilute  hydrochloric  acid. 

This  statement  may  be  verified  by  mak- 
ing other  salts  of  barium  that  are  insoluble 
in  water,  and  trying  to  dissolve  them  in 
dilute  hydrochloric  acid,  as  barium  car- 
bonate [BaCO.i]  and  barium  chromat 
[BaCr04].  These  being  insoluble  in  water, 
are  made  by  the  usual  method  of  preparing 
insoluble  salts.  (See  June  1917  issue  of  the 
Electrical  Experimenter,  p.  155.) 

It  will  thus  be  seen  that  the  barium 
chlorid  test  is  a  test  for  the  sulfate  ion  or 
radical,  and  not  for  the  acid  alone.  To 
verify  this  make  a  solution  of  any  soluble 
sulfate,  as  sodium  sulfate  [Na=  SOJ  or 
ammonium  sulfate  [NHJ.  [SOJ,  and  ap- 
ply the  test. 

The  carbonization  test  is  one  for  the  acid 
as  a  whole.  To  apply  it  in  four  cases,  take 
four  small  tubes  in  a  test  tube  rack — into 
one  put  a  gram  or  so  of  sugar,  into  another 
a  like  amount  of  powdered  starch,  into  a 
third  a  wad  of  paper,  and  into  the  last  a 
clean  splint.  Pour  on  each  of  these  5  cc.  of 
commercial  sulfuric  acid,  and  let  them  stand 
a  few  minutes.  Eventually  all  will  be  af- 
fected the  same  way  if  it  is  sulfuric  acid. 

EXPERIMENT  NO.  92 
Action  of  sulfuric  acid  on  water. 
Measure  out  in  a  graduate  10  cc.  of  cool 
water  from  the  faucet  and  pour  it  into  a 
medium-sized  test  tube.  Immerse  a  chemi- 
cal Centigrade  thermometer  in  the  water, 
carefully  resting  the  bulb  end  on  the  bot- 
tom of  the  tube,  as  the  glass  of  the  latter 
is  thin  and  mercury  is  heavy  (Fig.  83.) 
Let  it  stand  a  minute,  and  take  the  reading 
and  record  it.  Now  take  out  the  thermom- 
eter and  rest  it  in  another  tube  in  the  rack, 
then  measure  out  10  cc.  of  the  concentrated 
commercial  sulfuric  acid  and  slowly  pour  it 
into  the  water  of  the  first  tube.  At  once 
immerse  the  thermometer  in  the  mixture  of 
acid  and  water,  stirring  it  gently  with  the 
thermometer  tube;  when  the  mercury 
reaches  its  highest  point,  take  the  reading 
and  record  it.  Remove  the  thermometer, 
wash  it  thoroly  by  holding  it  under  a  jet 
of  water  to  wash  out  all  the  acid,  then  wipe 
it  dry  and  replace  it  in  the  case. 

Compare    the    difference    in    the  ther- 
mometer reading  both  after  placing  in  the 
water,  and  after  the  acid  was  added. 
(To  be  continued.) 


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September,  1917 


THE  ELECTRICAL  EXPERIMENTER 


359 


Scientific  Exchange  Columns 

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OVER  79,000  PEOPLE  READ  THIS  JOURNAL 


STOP!  LOOK!  SACRIFICE! 
•K"  Spark  Coils,  $1.25;  $2  Rotary  Potentiometer, 
$1.10;  Fixed  Variable  Condenser,  80c;  Junior 
Condenser,  35c;  Large  Accurate  Volt-Ammeter, 
$2;  $4  Tuning  Coil,  $2.50;  Large  Static  Machine, 
operates  large  X-Ray  Tubes,  $15;  Telephone  Trans- 
mitter, $1;  Small  Wireless  Key,  25c;  $1.25  Gajena 
Detector,  60c;  Brandes  Headset,  $4.50;  Pure 
Powdered  Magnesium  Metal,  $4  per  half  pound, 
75c.  per  ounce;  Metallic  Sodium,  $2.25  per  pound; 
many  other  chemicals  and  electrical  apparatus 
upon  application.  Satisfaction  guaranteed.  All 
answered.  J.  C.  Swimmer,  1904  Park  PI.,  Brook- 
lyn, N.  Y. 


WILL  TRADE  my  $11  omnigraph  with  dials 
for  chemicals  and  chemical  apparatus  or  a  6-60 
or  cash.  F.  Mursch.  321  W.  44th  St.,  New  York 
City. 


FOR  SALE — Gasoline  Engine,  Dyke  make.  Will 
sell  cheap.  Good  condition.  Henry  Lear,  2320 
Sauer  Ave.,  Cincinnati,  Ohio. 


EXCHANGE— One  110  volt  Direct  Current 
Voltmeter  for  steam  engine.  Ben  Jones,  Schlater, 
Miss. 


SACRIFICE— First  $48  takes  Smith  Motor 
Wheel  and  Bicycle,  in  good  condition,  or  I  will 
sell  both  separately.  Also  have  a  Buffet  B -flat 
Clarinet  in  excellent  condition.  Clyde  Rogers, 
Burlingame,  Kans. 


LOOKEY  HERE!!! 
Brand  New  Thordarson,  Type  "H,"  1  K.W. 
Transformer,  cost  $30,  condenser,  rotary  gap,  large 
X-Ray  Tube  and  Tesla  Coil,  giving  12-inch  spark, 
complete  $35.  Also  all  kinds  of  other  electrical 
goods  for  sale.  Chicago  Experimenters  please 
visit.  No  obligation  to  buy.  Phone  Lakeview 
1045.  Others  write  your  needs.  Have  almost 
anything  and  will  almost  give  it  away.  Ralph 
Weddeli,  1050  Buena  Ave.,  Chicago. 


FOR  SALE  OR  EXCHANGE— Aerothrust  twin 
cylinder  3  H.P.  rowboat  engine  with  32-inch  pro- 
peller in  perfect  condition  for  $25,  or  Victor  Pho- 
nograph and  records.  Otto  C.  Rolli,  426  Dewalt 
Ave.,  S.  W.,  Canton,  Ohio. 


FOR  SALE — Electric  Therapeutic  Apparatus 
Machine  Second-hand  in  good  condition,  used  by 
physicians  for  rheumatism  and  circulation.  Will 
sell  at  a  very  reasonable  price.  John  Ferguson, 
113  West  63d  St.,  New  York  City;  home,  364 
West  57th  St. 


FOR  SALE — 1913,  5  H.P.  Harley-Davidson 
Motorcycle  in  perfect  condition  all  the  way  round. 
Write  C.  H.  Calhoun,  Madison,  Fla.  

SWAF' — $60  worth  of  mechanical  and  electrical 
apparatus  and  instruments,  including  transformer, 
6.5  volts  100  amperes,  for  1  h.p.  gasoline  engine 
and  generator  or  6.3  1A  Kodak.  Stamp  for  de- 
scription. Walter  Garrett,  807  W.  Princess  St., 
York,  Pa. 


FOR  SALE — Maxwell  two-cylinder  Automobile, 
in  good  running  order;  also  Pittsburgh  Visible 
Typewriter.    Lyman  L.  Holmes,  West  Union,  Ohio. 


FOR  EXCHANGE — American  Correspondence 
School's  law  course,  same  as  new;  want  McFad- 
den's  Encyclopedia  of  Health  in  part  exchange; 
what  have  you?    J.  W.  Fulton,  Raynsford,  Mont. 


FOR  SALE— 15,000  meter  Navy  Type  Loose 
Coupler,  $10;  200  ohm  Phones,  $5;  Galena  and 
Electrolytic  Detectors;  V%"  Spark  Coil,  75c; 
Shocker,  50c,  and  $3.50  Telegraph  Set,  $1.  Har- 
old Hammer,  3225  23rd  Ave.,  So.,  Minneapolis. 


FOR  SALE — -Set  drafting  instruments,  rules, 
triangles,  etc.,  cost  $35,  for  $20.  Hydro-electric 
dynamo  (25  y.-3'A  a.),  cost  $16,  for  $10.  Two 
inch  spark  coil,  $4.50;  gas  coil,  switches,  sockets, 
wire,  etc.  About  75  different  chemicals  and  chem- 
ical glassware.  Telephone  instrument  with  ringer 
for  $1.50.    About  125  copies  electrical  magazines. 


Stamp  collection.  Six  volumes  (new),  "The  Prac- 
tical Reference  Library,"  cost  $23,  sell  for  $10. 
Lester  Chisholm,  329  Elm  St.,  Penn  Yan,  N.  Y. 

FOR  SALE — 39  hacket  Banjo,  A-l  condition, 
never  used,  $6,  including  banjo  books.  Richard 
Wood,  Oakley,  Cal. 


MICROSCOPE— Compound.  Society  screw  ob- 
jective. Inclinable  joint.  Adjustable  diaphragm. 
Cost  $26.50.  Will  sell  for  less  than  half  cost. 
Fine  for  photomicrography.  Other  microscopical 
supplies,  cheap.  Also  chemicals.  J.  W.  Weldon, 
5724  Montgall,  Kansas  City,  Mo. 


BARGAIN— 4,000  Meter  Navy  Coupler,  $7.25, 
cost  $12.  New  3,500  mile  Marconi  Cabinet  and 
Panel  Set,  $14,  cost  $19.50,  beauty.  Rotary  Gap, 
$4.80.  L.  G.  Hamilton,  378a  Fairmont  Ave.,  Oak- 
land, Cal. 


WANTED — Wireless  transformer,  state  size, 
make,  condition  and  price.  My  1-inch  coil  goes 
for  $3.    J.  R.  Dean.  Rochester,  N.  Y. 


FOR  SALE— $25  Erector  Set  complete  in  A-l 

condition,  used  once,  $20.  A.  E.  La  France,  40 
Ely  Street,  Holyoke,  Mass. 

"WANT  TO  SWAP"? 

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S   starts   again.     Do   you   realize   that   these  f 

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H    'THE  ELECTRICAL  EXPERIMENTER"  m 

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g  from  time  to  time  are  ample  proof  of  the  f= 

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-  vinced.  b 

:  ;.  : 

SELL— Goodell-Pratt  No.  29  Lathe,  $4.  Foot- 
power  Scroll  Saw,  $4.  Cabinet  Switch  Points, 
brass,  54"  x  yi",  6/32  thread,  lyic.  each,  prepaid. 
Wanted,  small  screw  cutting  lathe.  Clarence 
Vaughan,  Middletown,  N.  Y. 


FOR  SALE— All  in  excellent  condition:  Volt- 
amp  Type  J  Dynamo-motor,  $4.25,  weight  7'/2  lbs.; 
No.  3  Erector  Set,  $2,  weight  5  lbs.;  Daisy  Pump 
Gun,  $1.50,  weight  3'/2  lbs.;  2  lbs.  No.  18  Copper 
Aerial  Wire,  200  ft.  to  lb.,  60c.  per  lb.  Postage 
extra.    L.  Lindstrom,  Gresham,  Nebr. 


FOR  SALE — Electric  Therapeutic  Apparatus 
Machine,  second-hand,  in  good  condition,  used  by 
physicians  for  rheumatism  and  circulations.  Will 
sell  at  a  very  reasonable  price.  John  Ferguson, 
113  W.  63rd  St.,  home,  364  W.  57th  St.,  N.  Y.  City. 


OLIVER  TYPEWRITER,  excellent  condition, 
for  sale,  $20  cash,  worth  $40,  or  will  exchange 
for  scientific  apparatus.  T.  Steinmetz,  1460  St. 
Lawrence  Ave.,  Bronx,  New  York  City. 


FOR  SALE — Step-down  transformer,  five  sec- 
ondary voltages,  $10.  Write  for  particulars.  Ray 
Seitz,  531  Sixth  St.,  Portsmouth.  Ohio. 


SALE — Large  Receiving  Cabinet,  $15.  Send  for 
photo  and  particulars.  Also,  Spark  Coil  and  Gap, 
$2.25;  Kev,  $1;  Helix,  $1.25;  100  amp.  Lighting 
Switch,  $1.50;  Aerial  Switch,  $1.25;  y2  K.W.  Con- 
denser, $1.50.  E.  Hess,  2937  N.  Lawrence  St., 
Philadelphia. 


FOR  SALE  OR  EXCHANGE— Porter  motor,  K. 
&  D.  No.  2,  cost  $5,  for  head  phones  of  equal 
value.  Otto  Vestenig,  38  Ash  St.,  Waterbury, 
Conn. 


COLUMBIA  LANGUAGE  PHONOGRAPH 
(French  records),  complete  course,  everything  in 
the  best  condition.  Price,  $10.  I.  Alba,  1261 
Park  Ave.,  New  York. 


BARGAIN — 80  back  numbers  of  electrical  and 
mechanical  magazines,  electrical  raw  material,  gas 
engine,  etc  Send  stamp  for  list.  Walter  Burk, 
F'a'rfield,  Conn. 


FOR  SALE— 5,000  mile  Audion  Receiving  Set, 
complete,  $40.  George  Leonard,  11  Hamlet  St., 
Uphams  Corner,  Mass. 


VEST-POCKET  AUTOGRAPHIC  KODAK 
wanted.  Cash  paid  or  swap  even  for  unused 
new  Colby  Tuner  with  switches.  Brainerd  Strat- 
ton,  Oneida,  N.  Y. 


BARGAINS— Jeweler's  Elgin  Lathe  for  $10. 
Write  for  description.  Wireless  Apparatus^for 
sale,  send  for  list.  Clarence  Gunderson,  Albert 
Lea,  Minn. 


SWAP — Cabinet  receiving  set.  Moving  Picture 
Machine.  No  Toy.  Want  Blitzen  or  Type  D 
Tuner.  Variables,  Perikon  and  25  Automatic. 
Carl  Cardin,  Cushing,  Okla. 


WANTED — Used  Motorcycle  at  a  bargain. 
Those  having  one  for  sale,  please  write  to  Claude 
Gallaher,  R.  No.  3.    Vebler,  So.  Dak. 


FIXED  RECEIVING  CONDENSER  $1.  C. 
Phelps  Dodge,  Jr.,  Haystack  Gulch,  Brookvale, 
Colo. 


VIBROPLEX,  Two  sounding  relays  250  and 
150  ohms;  relay  50  ohms;  sounder  4  ohms;  Brandes 
phones,  all  $20.  Graflex  Camera,  3  A,  F.6.3,  $65, 
or  exchange  equal  value.  W.  F.  Dolezal,  342 
East  80th  St.,  N.  Y.  C. 


FOR  SALE — Two  Magneto  Telephones,  ten  sta- 
tions, $5  each.  Alfred  Theis,  1136  Decatur  St., 
Brooklyn,  N.  Y. 


FOR  SALE— $50  set  Harvard  Classics,  51  books, 
new,  $30;  also  15"  spark  coil  without  condensers. 
If  interested  write,  will  send  photo  of  coil  and 
open  bids.  Any  for  less  than  $40  ignored.  Harry 
J.  Frenz,  740  F'ranklin  Ave.,  Wilkinsburg,  Pa. 


BARGAINS— 6,000  meter  Navy  Type  Coupler, 
$4.50.  All  kinds  of  wireless  apparatus,  all  new. 
Write.     Walter  Johnson,  Salem,  Nebr. 


FOR  SALE— 30  American  Boy  Magazines,  $1.50; 
4  25c.  books,  75c;  receiver  and  cord,  50c;  Y2" 
coil,  minus  condenser,  $1.25;  Premo  00,  65c;  min- 
eral assortment,  25c.    Ivan  Juline,  Knoxville,  Iowa. 


You  benefit  by  mentioning  "The  Electrical  Experimenter"  when  writing  to  advertisers. 


360  THE  ELECTRICAL  EXPERIMENTER  September,  1917 


Opportunity  Exchange 


VOU  will  probably  find  more  opportunities  and  real  bargains  in  these  columns  than  anywhere  else  in  the  country.  Most  good  things  in 
*  life  are  hard  to  find  and  worth  going  after — these  little  ads  illustrate  that  point;  you  alone  will  be  the  real  loser  if  you  don't  take  the 
time  to  scan  through  these  columns.  . 

Advertisements  in  this  section  4c.  a  word  for  each  insertion.     Count  7  words  per  line. 

Name  and  address  must  be  included  at  the  above  rate.  Cash  should  accompany  all  classified  advertisements  unless  placed  by  an  accredited 
advertising  agency. 

Ten  per  cent,  discount  for  6  issues,  20  per  cent,  discount  for  12  issues  from  above  rate.    Objectionable  or  misleading  advertisements  not 

accepted. 

Advertisements  for  the  October  issue  should  reach  us  not  later  than  August  25. 

OVER  79,000  PEOPLE  READ  THIS  JOURNAL 

EXPERIMENTER  PUBLISHING  CO.,  INC.,  233  Fulton  Street,  New  York,  N.  Y. 


4 


AERONAUTICS 


AERIAL  AGE,  America's  only  illustrated  week- 
ly, presents  the  latest  developments  in  aeronau- 
tics throughout  the  world.  Up  to  the  minute 
technical  information  concerning  aero-engines, 
aeroplanes,  accessories  and  patents.  Complete 
model  news  and  instruction.  Trial  subscription 
six  months,  twenty-six  issues,  one  dollar.  Sample 
copy  10c.  Aerial  Age,  280  Madison  Ave.,  New 
York  City,  N.  Y. 


AUCTIONS 


AUCTIONEERS  make  from  $10  to  $50  a  day. 
Free  catalog.  Missouri  Auction  School,  Kansas 
City. 


BOOKS 


TO  GET  BETTER  PICTURES:  Read  the 
Amateur  Photographer's  Weekly;  illustrated; 
weekly  prize  competitions;  print  criticisms;  many 
unique  features;  $1.50  per  year;  three  months' 
trial  subscription  25c;  Abel  Publishing  Company, 
401   Caxton  Bldg.,  Cleveland,  Ohio. 

BOOKS — Scientific  and  wireless  supplied.  Let 
us  know  what  you  want  and  we  will  quote  you. 
Experimenter  Pub.  Co.,  233  Fulton  St.,  New 
York  City. 

A  BINDER  for  THE  ELECTRICAL  EXPERI- 
MENTER will  preserve  your  copies  for  all  time. 
Price,  50c.  Postage  on  3  lbs.  is  extra.  Send  for 
one  to-day.  Experimenter  Publishing  Co.,  233 
Fulton  St.,  New  York  City. 

FIRE  SALE  OF  SLIGHTLY  DAMAGED 
BOOKS.  Due  to  fire  in  our  stock  rooms,  a  great 
many  of  our  books  were  water  stained,  but  not 
otherwise  damaged.  Rather  than  dispose  of  them 
to  dealers  we  prefer  to  give  our  readers  the  bene- 
fit. Look  at  this  list!  Our  celebrated  Wireless 
Course,  160  pages,  400  illustrations;  List  of  Radio 
Stations  of  the  World;  Experimental  Electricity 
Course,  160  pages,  350  illustrations;  How  to 
Make  Wireless  Sending  Instruments.  These  four 
books  for  $1.50  prepaid.  Regular  selling  price 
of  these  four  books  is  $2.75.  We  guarantee  you 
will  be  satisfied.  Experimenter  Publishing  Co., 
Inc.,  233  Fulton  St.,  New  York  City. 

OLD  E.E.  BACK  NUMBERS— We  have  some 
valuable  old  E.E.  back  numbers  on  hand  as  per 
list  below: 

1915.  March    ..  price  each  $.20 

Jan  price  each  $.25      April    ..."      "  " 

Feb   "      "      "       May    "      "  " 

March  ....    "     "      "       June  ....  " 

April   ....    "      "       "        July    ....     "      "  " 

May    "     "      "       August   ..    "     "  " 

lune  ....     "      "       "        Sept   "      "  " 

July    "     "      "       Oct   " 

August  ...    "     "      "       Nov   " 

Sept   "     "      "       Dec   "      "  " 

Oct   "     "      "  1917. 

Nov   "      "       "        Jan   "       "  .15 

Dec   "     "      "       Feb   "      "  " 

March  ....    "      "  " 

1916.  April    ...  ' 

Jan   "      "    .20        May    " 

Feb   "     "      "       June  ....    "  " 

July  ....*'  "  " 
We  can  fill  orders  at  once  upon  receipt  of  your 
remittance  and  if  ycu  have  not  these  numbers  al- 
ready now  is  your  chance  to  get  them  as  they 
probably  will  be  snapped  jp  very  quickly.  Ex- 
perimenter Publishing  Co.,  233  Fulton  St.,  New 
York  City. 

CHEMICALS 

EXPERIMENTERS— Are  you  interested  in 
novel  chemical  experimentes  ?  Send  10c  for  large 
collection.    Merel  Sager,  44  Apple  St.,  Tiffin,  Ohio. 

100  WONDERFUL  CHEMICAL  EXPERIMENTS 
contained  in  our  book  on  Chemical  Science,  In- 
dustries, and  Magic,  together  with  free  Chemicals 
for  one  experiment  for  25c.  coin.  No  stamps 
accepted.  Our  catalog  of  Chemicals  and  apparatus 
for  stamp.  Send  for  description  of  our  $5  Chem- 
ical Laboratory  containing  44  expensive  chemicals, 
apparatus,  etc.  Zenith  Chemical  Laboratories, 
Duluth,  Minn. 


HELP  WANTED 


WANTED  MEN  AND  WOMEN,  18  or  over, 
everywhere  for  U.  S.  Government  Life  Jobs. 
War  necessitates  hundreds  appointments.  $75  to 
$150  month.  Short  hours.  Vacations  with  pay. 
Common  education  sufficient.  Write  immediately 
for  list  positions  open.  Franklin  Institute,  Dept. 
F  27,  Rochester,  N.  Y. 


H  Gentlemen:  = 
W  When  it  comes  to  results  the  "E.E."  H 
gj  is  all  broke  out  with  it.  Rcc'd  an  g 
]|  answer  with  the  same  mail  that  I  got  H 
S  the  magazine  on.  j| 
§jj  Yours  truly,  9 

=  Bernard  Brown.  H 


MISCELLANEOUS 

ELECTRICIANS— Send  50c.  for  10  Blue  Prints 
of  Motor  and  Generator  connections.  28  for  $1. 
10  A.C.,  4  D.C.  Motor  Winding  diagrams  for  $1. 
20  A.C.,  6  D.C.  and  6  Rotary  Converter  Draw- 
ings, $1.60.  32  A.C.,  6  D.C.  and  6  Converter 
drawings,  $2.25.  Winding  made  easy.  Superior 
Electric  Co.,  Superior,  Wyo. 

BE  POPULAR— Amuse  your  friends  wherever 
you  go  with  my  six  baffling  puzzles  and  tricks. 
"Complete  set  for  10c.  Address  H.  J.  Kunow, 
R.  2246  N.  Tripp  Ave.,  Chicago,  111. 

WE  HAVE  a  limited  number  of  beautiful  art 
pictures  of  the  following  famous  electrical  men  on 
hand.  Nikola  Tesla,  Thomas  A.  Edison,  Guglielmo 
Marconi,  Charles  P.  Steinmetz  and  Reginald  A. 
Fessenden.  These  make  a  handsome  decoration 
for  any  laboratory  or  workshop  and  should  be 
prominently  displayed.  Price  for  five,  prepaid, 
25c.  Experimenter  Pub.  Co.,  233  Fulton  St.,  New 
York  City. 


|§  151  LAKE  AVE.,  jj 

H  Lancaster,  N.  Y.  S 

S  Gentlemen:  g 
m  I  wish  to  tell  you  that  my  ad.  in  ■ 
=  the  E.  E.  was  a  great  success,  and  g 
M  exceeded  all  expectations.  I  had  re-  jj| 
H  plies  before  I  had  received  a  copy  of  II 
U  the  issue  myself.  This  goes  to  show  g 
^  tliat  every  issue  is  looked  for  with  = 
jj  great  interest,  and  the  wide  field  your  g 
|  paper  covers.  I  certainly  will  recom-  |f§ 
B  mend  it  to  the  amateurs  that  have  = 
H  something  to  trade  or  sell. 
S  Yours  respectfully,  M 

m  G.  W.  Bradford.  B 


PATENT  ATTORNEYS 


IDEAS  WANTED— Manufacturers  are  writing 
for  patents  procured  through  me.  Four  books 
with  list  hundreds  of  inventions  wanted  sent  free. 
I  help  you  market  your  invention.  Advice  Free. 
R.  B.  Owen,  130  Owen  Bldg.,  Washington,  D.  C. 

JOHN  M.  McLACHLEN,  attorney  -  at  -  law, 
Patent  causes.     Union  Trust  Bldg.,  Washington, 

D.  C. 

PATENTS  ON  EASY  PAYMENTS — Send 
model  or  sketch  for  Free  Search  and  Certified 
Registration  of  Your  Invention  for  Your  Protec- 
tion. Free  Book  Tells  What  to  Invent  and  How 
to  Obtain  a  Patent  on  Easy  Payments.  C.  C. 
Hines  &  Co.,  593  Loan  &  Trust  Bldg.,  Washing- 
ton, D.  C. 

PATENTS— R.  Morgan  Elliott  &  Co.,  Patent 
Attorneys,  Mechanical,  Electrical  and  Chemical 
Experts.  716-724  Woodward  Bldg.,  Washington,  D.C. 

PATENTS — Without  advance  attorney's  fees. 
Not  due  until  patent  allowed.  Send  sketch  for 
free  report.  Books  free.  Frank  Fuller,  Wash- 
ington, D.  C. 

PATENTS  worth  while.  No  free  booklets,  no 
premiums,  no  trading  stamps — nothing  but  good 
service.  Samuel  Herrick,  Master  of  Patent  Laws, 
Washington,  D.  C. 

PHONOGRAPHS 

BUILD  YOUR  OWN  PHONOGRAPH  or  manu- 
facture them  for  profit.  Drawings,  instructions, 
etc.,  Twenty-five  Cents.  Satisfaction  guaranteed. 
Circular  free.     Associated  Phonograph  Co.,  Dept. 

E,  Cincinnati. 

STAMPS 

STAMPS— 75,  all  different,  free.  Postage,  2c. 
Mention  paper.    Quaker  Stamp  Co.,  Toledo,  Ohio. 

SEND  POSTAGE  FOR  5  for  lc.  approvals. 
Lester  Schug,  942  Butler  St.,  Easton,  Pa. 

FREE— 12  JAPAN  AND  5  UNUSED  CUBA 
to  applicants  for  our  approvals.  F'ostage,  2c. 
Write  for  premiums. 

300  Different  30c. 

100  Different   5c. 

Universal    Stamp    Co.,    Mt.    Clemens,  Mich. 

SONG  WRITERS 

I  WILL  COMPOSE  music  to  your  song  poems 
or  arrange  your  melodies.  Send  for  my  latest 
success,  "Last  Night  While  I  Was  Dreaming,"  15c. 
postpaid.  Wm.  F.  Deely,  201  Valley  St.,  New 
Haven,  Conn. 


WIRELESS 

BIG  SALE!!     SELLING  OUT  BUSINESS!! 

200  excellent  54"  Spark  Coils  at  $1.25  each. 
Guaranteed  to  give  54"  spark.  J.  Eisgran,  1520 
St.  Marks  Ave.,  Brooklyn,  N.  Y. 

WILL  MAIL  one  pair  twelve  inch  Todd  Patent 
Circular  Plates  for  making  Wimshurst  Electric 
Machines  for  one  dollar.  Circulars  free.  Henry 
B.  Todd,  Meriden,  Conn. 

FIRE  SALE — We  have  a  great  many  slightly 
damaged  electrical  apparatus  and  supplies  on  hand 
which  we  are  selling  at  extraordinarily  low  prices 
while  they  last.  These  goods  were  damaged  in 
our  recent  fire  and  embrace  such  goods  as  tele- 
phone receivers,  telephone  cords,  printing  presses, 
telimphones,  detectors,  tuning  coils,  rotary  con- 
densers, leyden  jars,  porcelain  tube  insulators, 
strap  keys,  Gernsback  relays,  Inter-City  transmit- 
ting outfits,  etc.,  etc.  Send  for  list  and  prices  to- 
day. Wonderful  bargains  such  as  will  not  readily 
occur  again  for  a  long  time  to  come.  Electro 
Importing  Co.,  231  Fulton  St.,  New  York  City- 


ucceed  Through  Electricity 


This  interesting  story 
shows  you  the  way  to 
greater  success  in  the 
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This  is  the  Electrical  age. 
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say  there  are  no  better  electrical  books  published  at  any  price. 

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Send  no  money.    Examine  the  books  first.    Decide  for  yourself  that  they 
are  the  most  complete  library  of  Electricity  ever  published  and  that  you  can- 
not  afford  to  be  without  them.    Every  book  is  complete  in  itself,  but  the  complete  set  is 
the  best  bargain.   The  last  volumes  are  just  coming  off  the  press.  Jfr 

Pacif   P*llf  ITI  Atlf  S    Accept  this  unusual  offer  now —  j£r 

today.  Each  page— every  illus-  <^r 
tration  will  convince  you  of  the  big  value 
we  are  offering.   See  the  books  first, 
then  decide.   If  you  decide  to  keep 
them  you  can  make  settlement  at 

only  $1.00  monthly  until  paid  for.      ^}  Signature 

Theo.  Audel  &  Co.       °— ion 


iV 


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A  FEW  OF  THE  SUBJECTS 

Magnetism — Induction — Experiments  —  Dynamos 
— Electric  Machinery — Motors — Armatures — Arm- 


ature Windings— Installing  of  Dynamos — Electri- 
c  I  Instrument  Testing  —  Practical  Management 
of  Dynamos  and  Motors— Distribution  Systems- 
Wiring— Wiring  Diagrams— Sign  Flashers— Stor- 
age Batteries— Principles  of  Alternating  Currents 
and  Alternators— Alternating  Current  Motors- 
Transformers — Converters— Rectifiers— Alternat- 
ing Current  Systems— Circuit  Breakers— Measur- 
ing Instruments— Switch  Boards— Wiring— Power 
btations  —  Installing  — Telephone  — Telegraph  — 
Wireless— Rells— Lighting— Railways.  Also  many 
™«ern  Practical  Applications  of  Electricity  and 
Heady  Reference  Index  of  the  10  numbers. 


Theo.  Audel  &  Co. 
72  Fifth  Ave.,  N.  Y. 

Please  send   me  for 
FREE  examination 
Hawkins  Electrical 
Guides  (Price  $1.00  each). 
Ship  at   once   prepaid  the 
TEN  numbers.  If  satisfaetory 
I  agree  to  send  you  ?1.00  each 
month  until  paid. 


72  Fifth  Ave. 
NEW  YORK 


Business  Address. 


Residence  . 


Reference 


Sept.  E.E. 


You  benefit  by  mentioning  "The  Electrical  Experimenter"  -jshuv.  tsrbiaa  ;v  uU-nertiscrs. 


Our  21  Jewel 


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21  Ruby  and  Sapphire  Jewels — 
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Genuine  Montgomery  Railroad 

Dial- 
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per  month — a  great  reduction  in  watch  prices 
— -direct  to  you — positively  the  exact  prices 
the  wholesale  dealer  would  have  to  pay. 
Think  of  the  high  grade,  guaranteed  watch 
we  offer  here  at  such  a  remarkable  price.  And 
if  you  wish,  you  may  pay  this  price  at  the 
rate  of  $2.50  a  month.    Indeed,  the  days  of  ex- 
horbitant  watch  prices  have  passed.  Write  now. 

Caa  ff  ITil*cf  You  don't  pay  a 

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until  you  see  the  watch.    You  don't   buy  a 

Burlington  Watch  without  seeing  it.  Look  at  the  splendid  beauty  of  the  watch  itself.  Thin  model, 
handsomely  shaped — aristocratic  in  every  line.  Then  look  at  the  works.  There  you  will  see  the  master- 
piece of  the  watch  makers'  skill,  a  perfect  timepiece  adjusted  to  positions,  temperature  and  isochronism. 

Every  fighting  vessel  in  the  U.  S.  Navy  has  the  Burlington  Watch  aboard.  Many  have  over  100  Burlingtona  and 
a  few  have  over  200.   This  include*  every  torpedo  boat — every  submarine  as  well  as  the  big  Dreadnaughts. 


Burlington  Watch  Co 

19th  Street  and  Marshall  Blvd 
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361 


SOONER  or  later  you  will  be  standing  in  front  of 
the  mahogany  desk.    The  big  man  reclining  in  his 
office  chair  will  gaze  earnestly  at  you  while  his  keen 
gray  eyes  "take  you  in." 

When  this  big  moment  comes,  can  you  make  good? 
Will  you  "come  through"?  Will  you  be  just  another 
one  of  the  million  "little  fish"  trying  hard  to  land  a 
small  job  at  $15.00  a  week,  or  will  you  be  one  of  the  men 
that  DO  things,  at  a  salary  running  into  four  figures? 

Suppose  the  man  behind  the  desk  bombards  you  with 
questions,  such  as  these:  "Can  you  wire  a  switchboard? 
Can  you  lay  out  a  500  light  power  installation  on  the 
drafting  board?  Can  you  rewind  a  10  H.  P.  Direct 
Current  dynamo  armature?  Can  you  plan  and  install 
a  private  telephone  installation  and  75  phones  in  a  new 
factory?" 

Will  you  withstand  such  a  bombardment  ? 
No,  Sir.   Not  if  you  have  no  actual  experience  in  back 
of  you? 

WHAT'S  BACK  OF  YOU?  Just  a  little  personal 
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THE  ELECTRICAL  EXPERIMENTER 


October,  1917 


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at  $125,  $135,  $175,  and  $225 

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The  Columbia  Electric  Grafonola  175  E  is  designed  to  give  satisfaction  under  any 
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233  FULTON  STREET,  NEW  YORK 

Publisht  by  Experimenter  Publishing  Company,  Inc.  (H.  Gernsback,  President;  S.  Gernsback,  Treasurer;)  233  Fulton  Street,  New  York 


Vol.  V     Whole  No.  54 


OCTOBER,  1917 


No.  6 


FIRING  ELECTRIC  BOMBS  Front  Cover 

From  a  painting  by  George  Wall 
HOW  LORD  NORTHCLIFFE  HEARD  TWO  OCEANS  AT  THE 

SAME  TIME    365 

ELECTRIC  "ZIG-ZAGGER"  AIDS  SHIPS  TO  FOIL  U-BOATS  

••ZIG-ZAG"— A  NEW  THRILLER  FOR  THE  SEASHORE  

By  George  Holmes 

FIRING  BOMBS  BY  ELECTRICITY  By  H.  Gernsback 

-BURNELL  R.  FORD — SCIENTIST — ELECTRICAL  WIZARD". . . 

FREE  ELECTRICITY  FROM  THE  WIND  

By  H.  Winneld  Secor,  E.E. 

NEW    ELECTRO-THERAPEUTIC  APPARATUS  

By  H.  Rosenthal 

BRANDING  ORANGES  BY  ELECTRICITY  By  Harold  J.  Wood 

UNIQUE  REVOLVING  DANCING  FLOOR   376 

ARE  THERE  CURRENTS  ABOUT  A  MAGNET  ? — PART  II  

By  F.  F.  Mace 

NEW  PORTABLE  ELECTRIC  LAMP  FOR  MINERS  

By   F.  T.  Forster 

THE  EFFECT  OF  ULTRA-VIOLET  RAYS  ON  MILK  AND  OTHER 

ASPECTS   By  Dr.  Humbert  Bizzoni 

SOME  ELECTRICAL  PROPERTIES  OF  SILVER  SULFIDE  

By  George  W.  Vinal 

EXPERIMENTAL  PHYSICS— LESSON  8— LIGHT  

By  John  J.  Furia,  A.B.,  M.A.  386 


367 

369 
370 
371 

372 

373 
375 


380 
382 


383 
385 


RADIO-CONTROLLED  TORPEDO   DEVISED   BY  CALIFORNIA 

GENIUS  By  C.   W.  Geiger 

THE  AMATEUR'S  OPPORTUNITY  By  the  Editor 

A  RADIO-CONTROLLED  MODEL  BOAT  

By  H.  C.  Van  Benthuysen  and  Max  I.  Black 
MEASUREMENTS  OF  RADIO  ANTENNA  ON  SHIPBOARD  AND 

SOME  INTERESTING  COMPARISONS  

By  F.  A.  Hart 

HOW  TO  BUILD  A  UNIQUE  VARIABLE  CON1JENSER  

By  R.  U.  Clark,  3rd 

MAKING  AN  ELECTRIC  CLOCK— PART  II  

By  Thomas  Reed 

BUILDING  A  GOOD  CARBON  COMPRESSION  RHEOSTAT  

By  Albert  H.  Beiler 

TRIALS  OF  A  TROUBLESHOOTER  Bv  Thomas  W.  Benson 

CHEMICAL  ACTION  OF  STORAGE  BATTER  IES-V-PART  I  

By  Albert  W.  Wilsdon 

"HOW-TO-MAKE-IT  DEPT."   (PRIZE  CONTEST)   402 

WRINKLES,  FORMULAE  AND  RECIPES .. Edited  by  S.  Gernsback  404 
"WITH  THE  AMATEURS"  (PRIZE  LABORATORY' CONTEST) .  .  406 
"THAT  PERPETUAL  MOTION"— ANNOUNCEMENT  OF  PRIZE 

WINNERS    407 

LATEST  PATENTS  DIGEST   408 

PHONEY  PATENT  CONTEST   409 

"QUESTION   BOX"    410 


387 
389 


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393 


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399 


401 


Sub-Sea  Microphones 


HEN  reviewing  the  various  methods  which 
are  in  use,  or  which  have  been  proposed 
to  combat  the  submarine,  we  invariably 
are  led  back  to  the  microphone.  Indeed 
our  officials  are  coming  to  recognize  the 
'  microphone  more  and  more  each  day,  and 
just  now  at  least,  it  seems  to  be  in  a  fair 
way  towards  ultimate  success. 

Of  course,  we  must  admit,  the  difficulties  encoun- 
tered are  enormous,  and  the  ideal  microphone  for  sub- 
sea  work  as  yet  does  not  exist. 

In  order  to  guide  workers  in  this  field  we  will  en- 
umerate several  points,  not  well  understood  by  the  man, 
who  has  never  worked  with  sensitive  microphones  under 
water.  The  information  which  we  publish  in  the  inter- 
est of  all,  and  which  has  not  appeared  in  print  before 
has  been  secured  from  experts  who  have  actually  worked 
on  the  problem  for  months. 

To  begin  with,  a  microphone  working  on  dry  land 
is  a  totally  different  instrument  from  the  one  work- 
ing under  water.  Thus  it  will  not  do,  for  instance,  to 
take  any  sensitive  microphone  and  after  waterproof- 
ing it,  simply  sink  it  into  the  ocean.  A  microphone  as 
a  rule  has  a  sensitive  vibrating  diafram.  Imagine  sink- 
ing it  fifty  feet  below  water  where  the  pressure  is  some 
21  lbs.  per  square  inch — the  diafram  would  of  course 
cave  in:  For  that  reason  microphones  as  a  rule  are 
not  actually  sunk  in  the  water,  but  are  fastened  against 
the  inner  steel  shell  of  the  ships.  This  naturally  is  a 
poor  way,  as  much  of  the  instrument's  valuable  sensi- 
tiveness is  lost  thereby.  However,  means  have  already 
been  found  to  actually  keep  the  diafram  in  physical 
contact  with  the  ocean.  Nevertheless  improvements  are 
wanting. 

If  an  ordinary  super-sensitive  microphone  is  mounted 
on  a  ship  without  special  attachments  it  will  be  found 
to  be  worse  than  useless.  To  begin  with,  the  noise 
of  the  ship's  engine,  the  walking  about  of  the  crew, 
the  noise  of  the  waves  pounding  against  the  ship,  all 
make  it  impossible  to  hear  anything  else  in  the  'phones. 

If  on  the  other  hand  we  sink  the  microphone  clear 
of  the  ship,  only  supported  by  cables,  our  troubles  are 
far  from  ended.    The  first  thing  we  find  is  that  we 


must  sink  the  sensitive  microphob 
35  feet  below  the  ocean  level.  Far 
bring  a  constant  dull  pounding  int 
man  at  the  'phones,  due  to  the  noise  created  by  "The 
everbreaking  and  rolling  ocean  waves  above.  Even  at 
35  feet  below,  trouble  awaits  us.  If  the  microphone 
remained  perfectly  stationary  it  would  be  a  fine  thing, 
but  if  suspended  from  a  moving  vessel,  the  rush  of 
the  water  against  the  microphone  casing  produces  a  lot 
of  unwelcome  noise,  hard  to  get  rid  of. 

Most  of  these  troubles  are  slowly  being  mastered, 
but  far  too  slowly.  What  is  needed  are  many  more 
investigators  who  are  willing  to  actually  perform  experi- 
ments under  water.  Land  experience  with  microphones 
is  valueless. 

To  cite  a  few  more  points.  The  average  microphone 
works  well  only  if  in  one  position.  Incline  its  face  45° 
and  it  will  cease  operating  almost  entirely.  This  of 
course  is  due  to  the  shifting  carbon  grains.  Make- 
shifts, i.  c,  suspending  the  instrument  in  gimbal-rings 
like  a  compass,  will  not  always  do  under  water;  what 
is  wanted,  is  a  sensitive  microphone  which  is  not  in- 
fluenced when  turned  upside  down. 

It  has  also  been  found,  and  this  is  an  important  point 
to  remember,  that  using  a  "sea-diaf ram"  which  in  turn 
vibrates  a  layer  of  air,  the  latter  acting  on  the  micro- 
phone diafram,  will  not  work  at  all. 

Another  very  interesting  point  is  that  when  mount- 
ing microphones  on  each  side  of  a  vessel,  the  loudness 
of  the  incoming  sound  is  equal  in  both  telephone  re- 
ceivers, i.  e.,  if  a  submarine  is  on  the  starboard  side 
of  the  ship,  it  will  be  heard  just  as  loud  from  the 
port  side.  But,  the  difference  can  be  readily  detected 
and  very  accurately  too,  by  the  phase  difference  as 
heard  in  the  'phones.  In  other  words,  the  sound  will 
be  heard  a  fraction  of  a  second  earlier  in  one  ear 
than  in  the  other.  Small  as  this  difference  is,  even  a 
green  operator  will  detect  it  at  once. 

Finally,  the  motors  of  a  submarine  do  not  give  a  clear 
note  of  a  certain  frequency  in  the  listener's  'phones. 
Rather  we  hear  a  dull  rumbling  noise,  loud,  but  with- 
out any  definite  pitch. 

H.  Gernsback. 


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inks;  you  can  prepare 
magic     inks     and  papers, 
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and  milk  from  same 
vessel  and  do 


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Chemcraft  No.  2  is  much  larger  than  the  No.  1 
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There  are  many  rare  and  valuable  Chemicals  in-\ 
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The  No.  3  Chemcraft  is  the  biggest  and  most 
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reactions.  A  large  assortment  of  valuable  appara- 
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lamp.  8  test  tubes,  test  tube  holder,  test  tube 
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The  Chemcraft  hook  for  outfit  No.  3  is  complete 
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YOUR    CHEMICAL    LABORATORY.     YOU    WILL   LEARN    THOUSANDS    OF  VALUABLE 
AND  INTERESTING  THINGS.    BESIDES  HAVING  ALL  KINDS  OF  FUN. 

CHEMICALS  AND  CHEMICAL  APPARATUS 

Do  you  have  a  chemical  laboratory?  No  experimenter  should  be  without  one.  A  knowledge 
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October,  1917 


THE  ELECTRICAL 
EXPERIMENTER 


H.  GERN5B&CK  editpr 

H.  W.  5ECPR  d55DC1&TE  EDITOR 


Vol.  V.   Whole  No.  54 


October,  1917 


How  Lord  Northcliffe  Heard  Two  Oceans  at  the 


/^/^Jum^er  6 


ime 


A REMARKABLE  demonstration  of 
the  wonderful  telephone  network 
which  extends  over  the  entire 
United  States  was  recently  made 
for  the  benefit  of  Lord  North- 
cliffe and  his  party  on  the  occasion  of  their 


had  for  the  occasion  been  extended  to  a 
telephone  transmitter  on  the  shore  of  the 
Pacific  at  the  Golden  Gate.  Another  tele- 
phone was  connected  to  a  line  extending  to 
a  transmitter  on  the  shore  of  the  Atlantic. 
Thus  by  placing  his  ear  to  one  receiver 


per  wire.  There  are  870  pounds  of  copper 
wire  in  each  circuit  mile  and  2,960  tons  in 
the  entire  line.  The  line  crosses  thirteen 
States  and  passes  thru  Salt  Lake  City,  Den- 
ver, Omaha,  Chicago,  and  Buffalo,  with  a 
branch  that  runs  thru  Pittsburgh,  Wash- 


IT 


NEW  YORK  C/TY 


mm 

EHR 


Lord  Northcliffe,  During  His  Recent  Visit  to 
Atlantic  and  the  Pacific  Oceans  Si 

visit  to  the  offices  of  Theodore  N.  Vail, 
President  of  the  American  Telephone  & 
Telegraph  Company,  in  New  York  City. 

A  point  of  historical  interest  was  the 
listening  by  the  distinguished  visitor  to  the 
roar  of  the  Atlantic  and  Pacific  oceans 
simultaneously.  A  telephone  instrument 
was  connected  to  the  trans-continental  line 
reaching  to  San  Francisco  where  the  line 


the  Offices  of  Theodor  e  N.  Vail,  in  New  Y 
multaneously,  Over  the  Trans-continental  Tele 

and  then  to  the  other,  Lord  Northcliffe  was 
able  to  hear  first  one  ocean  and  then  the 
other,  and  by  placing  a  receiver  to  either 
ear  he  was  able  to  hear  both  oceans  simul- 
taneously. 

In  this  remarkable  telephone  line  there 
are  two  physical  and  one  phantom  circuits 
and  in  each  physical  circuit  there  are  two 
wires  and  6,800  miles  of  hard  drawn  cop- 


ork  City,  Had  the  Pleasure  of  Listening  to  the 
phone  Line,  3,400  Miles  in  Length. 

ington  and  Philadelphia.    In  the  main  line 
there  are  130.000  poles. 

The  power  that  sends  the  human  voice 
out  over  the  telephone  is  scarcely  greater 
than  that  of  a  breath,  yet  it  can  be  picked 
up  by  a  delicate  instrument,  conserved  over 
a  distance  of  3,400  miles,  and  reproduced 
perfectly  and  instantly  across  the  con- 
tinent. 


366 


THE  ELECTRICAL  EXPERIMENTER 


October,  1917 


NOW  COMES  THE  ELECTRO-MAG- 
NETIC RAPID-FIRE  AERO  GUN. 

The  accompanying  photo  shows  the  lat- 
est thing  in  aeroplane  guns  from  France. 
It  is  operated  by  an  electro-magnet  thus 
giving  the  aviator-marksman  instant  con- 


electric  cooking  apparatus  includes  novel 
designed  soup  kettles  and  boiling  vessels, 
varying  from  fifty  liters  capacity  to  four 
hundred  liters.  These  kettles  shown  in  the 
accompanying  photograph  have  insulating 
shells  for  retaining  the  heat,  as  well  as 


Photo  from  Underwood  &  Underwood. 
The  Machine  Gun  In  This  French  Aeroplane  Is    Fired    by    Means  of   An    Electro- Maanet 
Controlled  From  the  Aviator's  Seat.    Great  Rapidity  of  Fire  Is  Thus  Obtainable,  As  Well 

As  Increased  Accuracy. 

trol  of  the  gun,  no  matter  at  what  angle 
it  may  be  mounted. 

The  little  French  Nieuport  "scout"  plane 
is  a  great  fighting  machine  and  is  equipt 
with  an  electric  rapid  fire  gun  which  is 
worked  from  the  pilot  seat  by  a  special 
switch.  The  machine  is  furnisht  with  all 
the  latest  apparatus  evolved  from  three 
years  of  intensive  air  fighting. 

With  the  Nieuport,  French  airmen  have 
repeatedly  shown  the  German  birdmen  that 
there  is  not  room  for  two  brands  of  fight- 
ing men  in  the  air  and  the  Germans  have 
acquired  the  knack  of  being  "dropt." 


a  clever  system  of  utilizing  oil,  electrically 
heated,  between  the  casings,  similar  to  the 
system  of  double  boilers  ordinarily  using 
water  for  cereal  cooking. 

It  may  be  stated  that  these  oil-heated 
vessels  have  the  electric  heating  element  in 
the  bottom  arranged  with  two  and  three 
sets  of  windings  providing  for  twelve  kilo- 
watts, twenty-four  kilowatts  and  thirty-six 
kilowatts  as  desired.   The  roasting  and  bak- 


ovens  require  a  current  of  eight  kilowatts 
and  measure  three  thousand  four  hundred 
millimeters  long,  one  meter  wide  and  one 
thousand  two  hundred  and  fifty  millimeters 
high.  The  electric  broilers  are  mounted  on 
three  tables  and  measure  four  hundred  mm. 
by  six  hundred  mm.,  with  a  depth  of  sixty- 
five  mm.,  each  requiring  seven  kilowatts. 
The  capacity  of  these  broilers  is  two  hun- 
dred cutlets  per  hour,  while  the  total  ca- 
pacity of  this  kitchen  is  three  hundred  por- 
tions for  each  noon-day  meal. 

The  electric  coffee  vessels  have  a  ca- 
pacity of  five  hundred  liters  and  vary  in 
size  from  seventy-five  liters,  capable  of 
serving  three  hundred  cups  of  coffee,  to 
one  hundred  fifty  liters  having  a  capacity 
of  seven  hundred  cups  of  coffee  per  hour. 
The  smaller  coffee  pots  of  seventy-five  liters 
require  twelve  kilowatts,  while  the  larger 
ones  use  eighteen  kilowatts.  The  hot  water 
is  supplied  from  electrically  heated  vessels 
at  three  temperatures  automatically  con- 
trolled to  forty  degrees  Celsius,  sixty  de- 
grees Celsius  and  one  hundred  degrees 
Celsius.  The  electric  water  heating  boilers 
vary  in  size  from  1.5  cubic  meters  to  6.5 
cubic  meters  and  the  kitchen  is  equipt  with 
a  great  variety  of  other  cooking  utensils. 

The  electric  dishwashing  apparatus  is 
most  complete,  with  electrically  operated 
pumps  for  circulating  the  water  thru  the 
dishwashing  machine,  electric  conveyors 
and  electric  drying  oven.  It  will  be  seen 
that  the  kitchen  is  well  ventilated  with 
electric  fans  mounted  in  the  wall  and  win- 
dow casings  conveying  the  fumes  from 
cooking  outside  the  buildine. 

The  cost  of  electric  cooking  in  this  in- 
stallation is  said  to  be  extremely  low,  not 
exceeding  2.15  pfennig  (1/2  cent)  per  capita 
per  day,  including  the  total  current  con- 
sumption for  all  purposes,  while  for  cook- 
ing alone  the  cost  does  not  exceed  1.53 
pfennig  (1/3  cent)  per  capita  per  day. 


PARIS  RESIDENT  RECEIVES  IN- 
COME BY  RADIO. 

Mrs.  Elizabeth  K.  Baker,  of  Paris,  a 
daughter  of  Commodore  Norman  W.  Kitt- 


THE     GREATEST  ELECTRIC 
KITCHEN  IN  THE  WORLD. 
By  Frank  C.  Perkins. 

THE  electrical  connections  and  the  gen- 
eral design  of  the  electric  cooking, 
roasting  and  baking  equipment  of  the 
largest  electric  kitchen  in  the  world,  in 
operation  at  Siemensstadt  near  Berlin,  Ger- 
many, may  be  noted  in  the  accompanying  il- 
lustration. This  remarkable  electric  kitchen 
has  a  capacity  for  serving  three  thousand 
persons  in  four  groups  of  from  seven  to 
eight  hundred  workmen  in  each  group  be- 
tween the  hours  of  12  noon  and  2  P.  M., 
one-half  hour  beins;  allowed  for  each  group. 
The  electric  cooking  installation  was  de- 
cided upon  after  a  careful  study  of  the  use 
of  gas,  coal  and  steam  cooking  in  the  va- 
rious plants  of  the  Siemens  Schukert 
Werke,  in  other  cities  and  other  suburbs 
of  Berlin,  where  the  office  forces  as  well 
as  the  workmen  have  been  served  with 
meals  for  a  number  of  years  during  the 
noon  hour. 

This  new  electric  kitchen  is  the  most 
thoroly  equipt  kitchen  cooking  installment  in 
the  world,  as  well  as  the  largest,  being  pro- 
vided with  a  modern  cold  storage  and  re- 
frigerating plant  operated  by  electric  com- 
pressors, electrically  driven  kitchen  uten- 
sils of  every  description,  including  coffee 
grinders,  knife  sharpeners  and  meat  slicers, 
and  vegetable  cutters,  as  well  as  electric 
potato  paring  and  slicing  machines.  The 


Remarkable  Electric  Kitchen  In  Operation  at  Siemensstadt,  Germany,  With  a  Capacity  of 
3,000  Persons.    The  Food  Is  Prepared  by  Electrical  Machines  Besides  Being  Cooked  by  This 

Agency. 


ing  equipment  are  of  special  interest,  and 
may  be  noted  in  the  background  in  the  ac- 
companying   photographs.      The  baking 


son,  is  receiving  the  income  from  a  $175,000 
trust  fund  by  wireless  because  of  the  war 

situation. 


October,  1917 


THE   ELECTRICAL  EXPERIMENTER 


367 


Electric  "Zig-zagger"  Aids  Ships  to  Foil  U-Boats 


ACTUAL  experience  in  the  latest 
game — "dodging  the  submarines" — 
has  proved  the  efficacy  of  putting 
L  a  ship  over  a  zig-zag  course  once 
a  hostile  U-boat  has  been  encoun- 
tered. It  has  been  recommended  by  ma- 
rine experts  that  cargo  vessels,  whether 
armed  or  unarmed,  pursue  a  zig-zag  course 
or  better  still,  a  progressive  series  of  such 


a  rapid-lire  gun  of  from  three-  to  six-inch 
caliber,  the  U-boat,  once  it  has  come  within 
the  effective  range  of  the  gun,  must  stay 
below.  The  U-boat  commander  prefers  to 
get  within  one  thousand  yards  of  a  ship 
before  he  attacks,  and,  if  he  can  make  it, 
he  will  get  within  five  to  seven  hundred 
yards.  The  preferred  position  for  attack 
is  about  two  points  forward  of  the  beam. 


were  based ;  his  maneuver  for  getting  into 
firing  position  goes  for  nothing,  and  he 
has  to  try  again.  Unless  he  is  satisfied 
that  his  guns  can  greatly  outrange  the 
enemy,  the  U-boat  commander  does  not 
dare  to  use  his  surface  speed,  and  below 
the  surface  he  has  not  sufficient  speed  to 
overhaul  the  merchant  ship.  One  or  two 
misjudgments  of  this  kind  will  lose  so  much 


Instead  of  Relying  Entirely  on  the  Human  Factor  in  "Zig-Zagging"  the  Course  of  a  Ship  Attacked  by  a  Submarine,  the  Automatic  Elec- 
trical "Course  Zig-Zagger"  Here  Shown  Is  Proposed.    Electric  Motors  Swing  the  Rudder  to  Port  or  Starboard  As  the  Case  May  Be,  These 

Course  Changes  Being  Made  Automatically  by  a  Special  Electric  Clock  Switch. 


courses.  But  the  captain  of  such  craft  is 
not  over  fond  of  following  such  a  pro- 
cedure ordinarily  and  would  much  rather 
take  a  chance  on  "beating  it"  along  a 
straight  course.  Also,  he  is  apt  to  argue, 
"why  should  I  follow  a  zig-zag  course, 
which  is  several  miles  longer  than  a  straight 
one,  and  allow  the  submersible  time  to  catch 
up  to  me?"  Again,  zig-zagging  is  rather 
a  nuisance  anyway,  and  liable  to  get  the 
ship's  "log"  all  out  of  sorts :  unless  such 
courses  are  accurately  sailed  there  is  a 
chance  that  the  ship's  true  position  will  be 
misjudged. 

When  all  is  said  and  done,  however,  zig- 
zagging has  a  protective  value  which  it 
did  not  have  before  merchant  ships  were 
armed.   Now  that  the  tramp  is  apt  to  carry 


On  sighting  an  approaching  ship,  the  sub- 
marine heads  to  intercept  her  course,  sub- 
merges, and  then  takes  an  occasional  look 
at  her,  bringing  its  periscope  above  water 
for  a  few  seconds  only.  The  U-boat  com- 
mander estimates  the  speed  and  course  of 
the  ship;  submerges,  and  lays  his  own 
course  by  compass  while  below,  so  as  to 
bring  his  boat  within  torpedo  range  at  a 
point,  preferably  forward  of  the  beam. 

Now  consider  that  while  the  submarine 
is  below,  the  merchant  ship  changes  her 
course,  say  thru  an  angle  of  45  degrees, 
the  former,  on  coming  up  for  a  few  sec- 
onds' look  at  the  ship,  finds  that,  instead 
of  converging  to  meet  him,  the  merchant 
ship  is  sailing  in  a  direction  entirely  dif- 
ferent from  that  on  which  his  calculations 


time,  that  the  ship  will  have  a  good  chance 
to  pass  him  and  steam  beyond  torpedo 
range ;  indeed,  it  will  soon  have  gained  a 
lead  which  the  U-boat  cannot  overcome, 
except  by  coming  up  and  using  his  surface 
speed. 

So  we  come  back  once  more  to  the  zig- 
zag course  problem.  Not  only  is  more 
distance  covered,  but  the  navigating 
officer  may  forget  to  make  the  change 
of  course  from  one  leg  to  the  next  at  the 
proper  time,  and  so  throw  the  whole  zig- 
zag into  such  confusion  that  the  ship  willi 
not  know  where  she  is  with  regard  to  her 
true  course.  To  circumnavigate  this,  and 
with  a  view  to  making  the  running  of  the 
zig-zag  course  popular,  with  ship  captains, 
(Continued  on  page  414) 


The  Training  of  the  Young  Man  in  Industry 

By  E.  M.  Herr,  President  of  the  Westinghouse  Electric  &  Mfg.  Co. 

Written  exclusively  for  the  "Electrical  Experi:nente.  " 


SUCCESS  in  the  electrical  industry  is  attained 
just  as  is  success  in  any  other  industry, 
primarily  by  the  development  of  general  char- 
acter and  trustworthiness  followed  by  mastery 
of  the  details  of  the  particular  branch  of  the  in- 
dustry in  which  the  young  man  is  engaged. 

The  men  who  do  great  deeds  are  those  who  have  • 
been  again  and  again  tried  in  stress  and  strain  of 
hardships  and  difficulties,  perhaps  in  an  entirely  in- 
conspicuous way,  but  who  have  worked  thru,  never 
shirking,  and  have  willingly  taken  up  greater  and 
greater  burdens  as  they  came  to  their  hands,  being 
most  concerned  not  with  the  immediate  rewards  to 
be  gained  but  with  the  feeling  that  progress  was  be- 
ing made  in  the  work  entrusted  to  them  and  that 
they  had  succeeded  in  their  immediate  task  with  the 
result  that  their  character,  knowledge,  training  and, 
more  important  still,  their  courage  and  tenacity  were 
strengthened  for  overcoming  still  greater  difficulties 
and  bearing  more  and  larger  responsibilities. 

Great  knowledge  and  learning  will  not  alone  suf- 
fice for  attainment  of  success  in  the  industrial  world, 
for  if  they  would,  we  would  see  the  great  scholars 
bearing  the  greatest  responsibilities.  History  shows 
us  that  its  greatest  men  .were  generally  not  men 
possest  of  unusual  learning,  or,  if  they  were,  other 
great  qualities  of  mind  and  character  were  present  to 
an  even  more  remarkable  extent. 

Experience  and  a  broad  •  contact  with  affairs  is 
not  all  that  is  required,  for  many  men  of  widest 
experience  and  who  have  been  in  touch  with  world- 
wide affairs  are  ineffective  and  frequently  unable  to 
assume  great  responsibilities  depending  on  their 
own  efforts  and  initiative. 

Much  good  effort  is  often  wasted  and  many  a 
valuable  man  fails  to  make  good  because,  to  use 


the  old  familiar  phrase,  he  is  "a  round  peg  in  a 
square  hole"— by  persevering,  possibly,  in  a  most 
admirable  manner,  in  a  position  for  which  he  is 
unfit;  whereas,  were  he  placed  in  a  position  to 
which  his  talents  were  better  suited,  his  entire 
source  of  energy  would  be  devoted  to  an  attain- 
ment of  a  high  degree  of  perfection. 

The  gradual  assumption  of  more  and  more  dim- 
cult  work  with  its  attendant  troubles,  and  the  success- 
ful solution  of  them  by  his  own  efforts  all  tend  to 
the  development  of  the  successful  man. 

A  young  man  should  perform  his  daily  task  for 
the  satisfaction  of  its  accomplishment  rather  than  the 
expectation  of  an  immediate  reward.  A  reward,  and 
a  rich  one,  will  surely  come  to  him  who  can  and  does 
excel  his  fellow  in  doing  things,  no  matter  how  bur- 
densome or  onerous,  provided  they  are  worthy  and 
especiallv  if  such  excellence  is  in  work  or  methods 
more  difficult  than  is  usually  encountered.  Ihe  re- 
ward may  not  come  when  expected— it  may  even  be 
delayed  until  the  worker  feels  great  discouragement 
and  can  see  no  prospect  of  the  recognition  and  reward 
he  has  justly  earned. 

Experience,  however,  shows  that  reward  for  unusu- 
al and  successful  efforts  must  come  and  if  deferred, 
as  it  often  is  by  uncontrollable  circumstances,  it  will 
ultimately  be  paid  with  interest  well  compounded. 


The  Westinghouse  Electric  &  Manufacturing  Co.  em- 
ploys at  the  present  time  approximately  25,000  people. 
The  capital  stock  is  $75,000,000.  The  gross  sales  for 
last  year  were  approximately  $90,000,000  and  will  be 
considerably  in  excess  of  that  this  year.  The  plants 
occupy  approximately  100  acres  of  floor  space.  The 
company  controls  several  thousand  patents. 


October,  1917 


THE  ELECTRICAL  EXPERIMENTER 


369 


WHERE  ELECTRICITY  CAN  BE 
USED  ON  THE  FARM. 

Farmers  are  constantly  hearing  of  the 
advantages  of  electricity  on  the  farm,  what 
it  will  do  for  them  and  its  wide  application. 
Some  of  this  has  been  rather  vague  and 
The  Society  for  Electrical  Development 
has  prepared  a  list  of  some  104  applications 
appended  here. 

Of  course,  every  farm  will  not  find  it 
economical  to  install  all  the  equipment 
listed,  but  every  farm  will  find  profitable 
use  for  some  of  it.  Many  of  the  applica- 
tions can  be  handled  best  by  a  community 
of  interests,  for  instance,  electric  thresh- 
ing and  harvesting  machinery,  hulling  ma- 
chinery, oil  concentrating  plants,  hay  balers, 
etc  High  priced  machinery  used  only  for 
short  periods  during  the  year  is  applicable 
to  this  community  treatment. 


'Zig-Zag"— A  New  Thriller  for  the  Sea  Shore 


By  GEORGE  HOLMES 


Oat  Crushers 
Alfalfa  Mills 
Horse  Groomers 
Horse  Clippers 
Hay  Cutters 
Clover  Cutters 
Corn  Shellers 
Ensilage  Cutters 
Corn  Crackers 
Branding  Irons 
Currying  Machines 
Feed  Grinders 
Failing  Machines 
Livestock  Food  Warm- 
ers 

Sheep  Shears 

Threshers 

Grain  Graders 

Root  Cutters 

Bone  Grinders 

Hay  Hoists 

Clover  Hullers 

Rice  Threshers 

Pea  and  Bean  Hullers 

Gas-Electric  Harvesters 

Hay  Balers 

Portable  Motors  for 
Running  Threshers 

Fanning  Mills 

Grain  Elevators 

Huskers  and  Shredders 

Grain  Drying  Machines 

Binder  Motors 

Wheat  and  Corn  Grind- 
ers 

Milking  Machines 
Sterlizing  Milk 
Refrigeration 
Churns 

Cream  Separators 
Butter  Workers 
Butter  Cutting-Printing 
Milk  Cooling  and  Cir- 
culating Pumps 
Milk  Clarifiers 
Cream  Ripeners 
Milk  Mixers 
Butter  Tampers 
Milk  Shakers 
Curd  Grinders 
Cassin  Grinders 
Pasteurizers 
Bottle  Cleaners 
Bottle  Fillers 
Concrete  Mixers 
Cider  Mills 


Cider  Presses 
Spraying  Machines 
Wood  Splitters 
Auto  Trucks 
Incubators 
Hoovers 
Telephones 
Electric  Bells 
Ice  Cutters 
Fire  Alarms 
Electric  Vehicles 
Electro  Cultures 
Water  Supply 
Pumping 
Water  Sterilizers 
Fruit  Presses 
Blasting  Magnetos 
Lighting 

Interior  Telephones 

Vulcanizers 

Pocket  Flash  Lights 

Ice  Breakers 

Grindstones 

Emery  Wheels 

Woodsaws 

Forge  Blowers 

Drop  Hammers 

Soldering  Irons 

Glue  Pots 

Cord  Wood  Saws 

Egg  Testers 

Burglar  Alarms 

Bell  Ringing  Trans- 
formers 

Devices  for  Killing  In- 
sects 

Machine  Tools 

Molasses  Heaters 

Vacuum  Cleaners 

Portable  Lamps  to  At- 
tract Insects 

Toasters 

Hot  Plates 

Grills 

Percolators'  (Coffee) 

Irons 

Ranges 

Toilette  Articles 
Water  Heaters 
Fans 

Egg  Boilers 
Heating  Pads 
Dish  Washers 
Washing  Machines 
Curling  Irons 


X-RAYING  RING  NEBULAE. 

At  the  last  meeting  of  the  British  As- 
tronomical Association  at  Sion  College  an 
application  of  X-rays  to  obtain  by  analogy 
a  test  of  a  theory  of  the  structure  of  "ring" 
nebulae  was  shown  by  Mr.  W.  H.  Steaven- 
son.  His  idea  was  that  the  "ring"  appear- 
ance did  not  necessarily  imply  the  shape  of  a 
ring,  but  could  be  produced  by  a  hollow 
globular  form,  the  suggestion  being  that  the 
absence  of  light  in  the  interior  of  the  "ring" 
is  due  to  the  thinness  of  the  shell,  which 
appears  much  thicker,  and,  consequently, 
brighter,  just  outside  the  central  portion. 
X-ray  photographs  of  rubber  tubes  showed 
a  very  similar  appearance,  rubber  globes  of 
sufficient  thickness  not  being  available. 


WE  ALL  enjoy  going  to  the  sea- 
shore, when  the  summer  comes 
around  each  year,  and  all  look 
for  thrills,  be  they  young  or  old, 
grown-ups  as  well  as  kiddies,  it's 
bound  to  get  us  all — this  beat-it-f rom-the- 
city  spirit — to  get  out  in  the  great  outdoors 
and  let  loose ! 

The  attraction  recently  invented  by  an 


and  begins  its  descent  from  the  top  of 
the  tower  with  a  zig-zag  motion,  from  which 
the  attraction  derives  its  name. 

The  cars  after  leaving  the  top  descend 
by  gravity,  traveling  over  a  series  of  in- 
clined rails  which  are  arranged  one  pair 
above  the  other  in  a  vertical  zig-zag  line 
in  such  a  manner,  that  the  traveling  seats 
are  brought  to  a  stop  at  the  lower  ends  of 


The  Latest  Electrically  Operated  Thriller  for  Pleasure  Resorts  Is  Known  as  the  "Zig-Zag." 
The  Passengers  Are  Hauled  to  the  Top  of  the  Tower  by  a  Motor-driven  Cable.    They  Then 
Start  Their  Ziz-Zag  Downward  Journey  by  Gravity. 


Eastern  man,  Mr.  Hartman,  called  the  "Zig- 
Zag,"  will  soon  be  seen  by  the  crowds  at 
pleasure  resorts. 

The  main  part  of  the  device  is  a  large 
steel  tower  about  a  hundred  feet  high,  an 
object  of  beauty  and  awe,  especially  at 
night,  when  hundreds  of  lamps  shall  blaze 
forth  over  the  entire  structure.  At  the 
top  of  the  tower  there  will  be  a  large  ball 
of  revolving  lamps  and  searchlights  to  en- 
hance the  scene. 

The  passengers  are  seated  in  a  small  car 
which  is  drawn  by  an  endless  sprocket  chain 
to  the  top  of  the  tower.  When  the  car 
reaches  the  top  it  is  automatically  released 


each  pair  of  parallel  running  rails,  drop  a 
certain  predetermined  distance  upon  the 
next  lower  pair  of  rails  and  then  travel 
along  such  rails  in  the  opposite  direction 
downward,  until  they  reach  in  a  zig-zag  line 
the  lowest  pair  of  rails.  A  further  swing- 
ing movement  is  obtained  at  the  sudden 
temporary  stops  by  the  living  force  of  the 
traveling  suspended  seats. 

A  close  inspection  of  the  illustration  will 
give  the  reader  a  good  conception  of  how 
the  mechanism  works. 

Mr.  Hartman  does  not  state  how  the  pas- 
senger's "inside  mechanism"  works  during 
the  trip,  but  we  presume  people  will  like  it. 


DATE  OF  ISSUE. — As  many  of  our  readers  have  recently  become  unduly  agitated  as  to  when  they  could  obtain  The  Electrical 
Experimenter,  we  wish  to  state  that  the  newsstands  have  the  journal  on  sale  between  the  fifteenth  and  the  eighteenth  of  the  month  in 
the  eastern  part  of  the  United  States  and  about  the  twentieth  of  the  month  west  of  the  Mississippi  River.  Our  subscribers  should  be  in 
possession  of  their  copies  at  these  dates.  Kindly  bear  in  mind,  however,  that  publications  are  not  handled  with  the  same  dispatch  by  the 
Post  Office  as  a  letter.  For  this  reason  delays  are  frequent,  therefore  kindly  be  patient  and  do  not  send  tis  complaints  as  to  non-arrival 
of  your  copy  before  the  twenty-fifth  of  the  month. 


370 


THE  ELECTRICAL  EXPERIMENTER 


October,  1917 


Firing  Bombs  by  Electricity 

By  H.  Gernsback 


MODERN  bombs  as  used  in  trench 
warfare  are  divided  in  two  class- 
es, namely:  the  "time-fuse"  bomb, 
and  the  "contact"  bomb.  The 
former,  which  at  the  beginning 
of  the  war  was  a  rather  crude  affair,  has 
now  been  greatly  improved  upon,  and  as 
a  rule  will  go  off  five  seconds  after  its  re- 
lease. This  type  has  a  kind  of  trigger 
which  is  presst  against  the  body  of  the 


"if  you  hold  it  too  long,  you  jeopardize 
your  own  chances  of  being  able  to  throw  it 
at  all." 

As  mentioned,  this  refers  to  the  old  tim- 
ers, lit  by  a  match  or  a  cigarette,  and  does 
not  hold  true  for  the  modern  type,  timed 
to  go  off  in  five  seconds. 

But  the  trouble  with  the  modern  type  is 
that  it  is  impossible  to  make  it  go  off  the 
moment  it  enters  the  enemy's  trench ;  it 


ically.  We  have  a  bomb  weighing  from 
five  pounds  upward,  to  be  thrown  in  the 
enemy's  trench  precisely  as  any  other  bomb. 
It  can  be  thrown  by  mean?  of  catapult  or 
other  suitable  means.  The  construction  of 
the  bomb  is  shown  in  Fig.  1.  It  has  a  hol- 
low center  which  contains  in  a  shell  a  reel, 
upon  which  is  wound  a  thin  flexible  electric 
cable.  This  reel  runs  free  on  ball  bearings 
so  as  to  give  a  minimum  of  friction.  It 


Why  Take  Chances  With  Time-fused  Bombs  When  This  Newly  Deviled  Electric  Bomb  Is  Sure  to  Explode  at  Exactly  the  Time  Desired. 
When  the  Bomb,  Filled  With  Explosive  or  Chloroform,  Reaches  theDesired  Point,  a  Switch  Is  Closed  and  the  Missile  Is  Detonated.  They 

Are  Thrown  With  a  Catapult  In  the  Manner  Illustrated. 


bomb :  thus  when  the  latter  is  released  it 
will  take  the  trigger  just  five  seconds  to 
ignite  and  consequently  explode  the  bomb. 

The  second  bomb,  as  its  name  implies, 
goes  off  the  moment  it  strikes  a  hard  body, 
showering  destruction  all  about  it.  For 
trench  warfare,  bombs  are  highly  effective, 
and  if  the  enemy's  trenches  are  "bombed" 
in  a  systematic  manner,  the  men  as  a  rule 
become  very  much  demoralized. 

Bombs  vary  in  size  from  the  small  hand 
bomb,  the  size  of  a  baseball  and  containing 
from  six  to  ten  ounces  of  high  explosive, 
to  the  large  cylinder-shaped  affair  contain- 
ing as  much  as  thirty  pounds  of  Trinitro- 
Toluol.  The  latter  kind  of  course  cannot 
be  thrown  by  hand  on  account  of  their 
weight,  but  are  projected  thru  the  air  either 
by  a  modern  spring  operated  catapult  or 
by  a  mortar-type  "Minenwcrfcr,"  first 
brought  out  by  the  Germans. 

The  chief  trouble  with  the  old  time  fuse 
type,  to  quote  Captain  Ian  Hay  Beith,  is 
that  if  the  bomb  is  thrown  too  soon  "the 
other  fellow  has  plenty  of  time  to  pick  it 
up,  and  throw  it  back  to  the  sender."  in- 
cidentally killing  him.    On  the  other  hand. 


either  explodes  a  few  seconds  too  soon  or 
a  few  seconds  too  late.  In  the  former 
case  the  bomb  does  not  do  much  harm, 
but  merely  sprinkles  the  trench  with  steel 
fragments.  In  the  latter  case  the  men  in 
the  trenches  find  time  to  run  for  cover ; 
i.  e.,  dodging  the  bomb.  In  both  cases  not 
very  much  harm  is  done.  It  is  on  record 
that  it  takes  almost  thirty  bombs  to  kill  one 
man!  This  certainly  is  low  efficiency.  Also 
not  all  bombs  go  off,  this  being  particularly 
the  case  with  contact  bombs ;  if  the  latter 
hit  a  soft  body,  such  as  straw  or  mud,  they 
often  fail  to  explode.  Hence  the  great 
waste  and  low  efficiency  of  the  present 
bombs. 

With  a  view  to  rectifying  several  of 
these  defects,  as  well  as  gaining  certain  new 
important  improvements,  the  electrically 
fired  bomb  is  suggested.  At  first  blush  the 
idea  of  putting  a  "string"  on  a  bomb  seems 
foolish,  awkward,  as  well  as  troublesome. 
But  if  we  study  the  idea,  it  will  be  found 
that  the  new  improvements  probably  greatly 
overbalance  the  imaginary  defects,  if  such 
there  are. 

Our  front  cover  illustrates  the  idea  graf- 


will  thus  be  seen  that  as  the  bomb  pro:e<:ds 
in  its  flight  thru  the  air,  the  thin  electric 
wire  is  played  out,  without  in  any  way  re- 
tarding or  impeding  the  flight  of  the  bomb. 
Naturally,  the  reel  must  contain  a  sufficient 
wire  supply  to  reach  from  our  own  to  the 
enemy's  trench. 

The  space  between  the  shell  containing 
the  wire  reel  and  the  bomb  body  proper 
is  packed  with  the  usual  high  explosive. 
The  ends  of  the  wire  cable  inside  of  the 
bomb  are  inserted  into  the  explosive;  the 
latter  can  therefore  be  set  off  by  means  of 
a  fine  platinum  wire  electrically  heated  to 
incandescence  or  by  any  other  well-known 
firing  method. 

The  electric  cable  being  of  rubber  in- 
sulated stranded  wire  can  be  quite  thin, 
there  being  almost  no  strain  whatsoever 
on  the  wire  cable.  This  will  be  understood 
after  a  second's  reflection,  for  mechanically 
the  bomb  has  nothing  to  do  with  the  cable. 
The  wire  reel  having  ball  bearings  simply 
unwinds  as  the  bomb  moves  on,  therefore 
there  can  be  no  strain  beyond  the  weight 
(Continued  on  page  416) 


October,  1917  THE  ELECTRICAL  EXPERIMENTER 

"BURNELL  R.  FORD— 

SCIENTIST  ELECTRICAL  WIZARD" 


37 


THUS  do  our  friends,  the  theatrical 
managers,  announce  the  electrical 
star  of  theaterdom — he  of  the  flash- 
ing sparks  and  mastodonic  Tesla 
coils.  Mr.  Ford  is  one  of  the  most 
successful  scientific  lecturers  in  the  coun- 
try and  is  now  on  a  Chautauqua  tour. 

"The  late  Elbert  Hubbard  described  elec- 
tricity as  'the  juice.'  Since  Benjamin 
Franklin  brought  it  from  the  sky  with  a 
kite,  no  better,  or  more  scientific  definition 
has  been  made.  Yet  the  remarkable  mis- 
understanding of  the  nature  and  properties 


The  Electric 
"Boogieman"  Is 
Made  By  Cutting 
Out  a  Cardboard 
Figure  of  the  De- 
sired  Shape. 
When  Coated 
With  Tinfoil  and 
Charged  by  One 
Terminal  of  An 
Oudin  Coil  This  Is 
What  You  See. 


mouth  (by  using  a  spoon  for  example) 
and  also  to  employ  a  sufficiently  high-fre- 
quency Tesla  current.  Such  a  current,  os- 
cillating at  say  100,000  cycles  per  second, 
will  exert  no  muscular  effects  and  simply 
passes  over  the  skin  of  the  lecturer. 

The  interesting  effect  shown  in  the  cen- 
ter top  photograph,  is  attained  by  cutting 
out  a  cardboard  figure  and  covering  it 
with  tinfoil.  This  may  be  laid  on  a  pho- 
tographic plate  and  charged  for  a  second 
with  a  high-frequency  electrode.  If  de- 
sired a  larger  figure  may  be  cut  out  of 


Here  Is  Shown  a  Remarkable  Demonstration  of  Electrical 
Welding  Thru  Two  Human  Bodies.  Stiff  Iron  Wires  Are 
Forever  Welded,  the  Current  Flowing  From  the  Lecturer  to 
An  Assistant.  Capable  of  the  Simplest  Explanation,  This 
Experiment  Is  Nevertheless  An  Awe-Inspiring  One. 


The  Photograph  Shows  the  Lighting  of  An  Ordinary  Candle 
by  Means  of  a  Stream  of  Water.  In  Connection  With  This 
Experiment,  the  Lecturer  Becomes  a  Human  Dynamo,  Light- 
ing Arc  Lights  by  Holding  the  Carbons  In  His  Hands  and 
Handling  3,000,000  Volts  of  Electricity. 


of  electricity  seems  to  be  general  and  per- 
manent. In  the  entire  realm  of  popular 
education  no  one  thing  can  be  of  more  im- 
portance than  to  educate  the  people  on  what, 
to  them,  are  the  mysteries  of  electricity. 
To  do  this  in  a  scientific,  yet  plain  and 
thoroly  entertaining  way,  is  no  small  ac- 
complishment. The  management,  after 
much  search  and  many  discouragements,  has 
found,  in  the  person  of  Burnell  R.  Ford, 


such  a  man," — so  reads  our  program. 

One  of  the  startling  experiments  per- 
formed by  the  lecturer  is  that  of  welding 
by  current,  which  is  made  to  pass  thru 
the  human  body.  Stiff  iron  wires  are 
solidly  welded  as  shown  above,  the 
heavy  current  flowing  from  the  lecturer's 
mouth  to  that  of  his  assistant.  The  essen- 
tial thing  to  be  watched  in  making  this  ex- 
periment is  to  have  metal  contact  with  the 


thin  wood  and  coated  with  tinfoil.  When 
this  is  exhibited  against  a  dead-black  back- 
ground and  properly  excited  by  connection 
to  a  powerful  Oudin  or  Tesla  high-fre- 
quency coil  the  effect  on  the  audience  is 
truly  remarkable.  The  foil-covered  figure 
should  be  charged,  preferably  from  the 
live  terminal  of  an  Oudin  coil. 

The  right  top  view  shows   a  mystify- 
(Continued  on  page  422) 


At    Left:— Lighting    Indian   Clubs   by  Hlgh- 
Frequency  Currents  Past  Thru  the  Body. 

Above: — The  Lecturer  Lights  Up  a  Bank  of 
Lamps  to  Full  Brilliancy,  the  Current  Flow- 
ing Thru  His  Body. 

At  Right: — Lighting  a  Candle  by  a  Spark 
From   the   Tongue — A    Mystifying  Electrical 


372 


THE  ELECTRICAL  EXPERIMENTER 


October,  1917 


Free  Electricity  from  the  Wind 

WINFIELD  SECOR 


WIND  pressure  as  a  natural  source 
of  power  has  been  in  practical 
use  for  driving  grist  mills  and 
pumps  for  the  last  six  hundred 
years.  The  efficiency  and  utility 
of  the  wind-motor  has  increased  along  with 
the  development  of  modern  manufacture 
until  the  all-steel  wind-motor  of  to-day  is 
a  highly  efficient  machine,  giving  more 
power  for  every  dollar  of  capital  invested 
than  either  steam,  gas,  or  waterfall.  The 
great  drawback  to  the  development  and 
general  use  of  wind  power  has  been  the 
intermittent  character  of  the  power.  At- 
tempts have  been  made  in  the  past  to  gen- 
erate electricity  with  wind  power  and  store 
the  electricity  for  lighting  purposes. 
Theoretically,  this  combination  should  be 
perfect,  but  many  difficulties  have  been  ex- 
perienced by  those  who  have  tried  to  put 
this  combination  into  practise.  The  low 
speed  of  the  wind-wheels  made  it  difficult 
to  get  a  satisfactory  transmission  of  power 
from  the  wind-wheel  to  the  dynamo.  To 
operate  at  high  efficiency  the  wind  wheel 
had  to  run  slow  and  the  dynamo  at  high 
speed,  thus  introducing  a  dangerous  ele- 
ment in  the  way  of  high  speed  gearing. 

In  the  new  type  wind  motor  plant  here 
illustrated  this  difficulty  is  claimed  to  have 
been  overcome.  A  special  slow-speed 
dynamo  has  been  designed  to  couple  direct 
on  to  the  driving  axles  of  the  wind-wheels, 
and  a  strong  gear  of  simple  design  con- 
nects them  together. 

The  inventor,  Mr.  M.  A.   Mulrony,  of 


By  H. 

Australia,  has  designed  two  sizes  of  rural 
lighting  outfits  of  this  type,  and  which  for 


work  together,  like  two  horses,  in  pulling 
along  their  common  load — the  dynamo. 
When  the  two  wind-wheels  start  turning, 
the  dynamo,  which  is  direct  geared  to  the 
differential,  starts  generating  electricity, 
and  as  soon  as  the  electric  pressure  of  the 
dynamo  rises  higher  than 
that  of  the  storage  battery 
an  electric  valve  trips,  and 
the   electricity   begins  to 


Sectional  View  of  Newly  Perfected  Wind- Motor  and 
Dynamo  Unit.    The  Storage  Battery  Keeps  the  Volt- 
age Even.    The  Plant  Stands  Any  Wind  Pressure. 


Every  Suburban  Dweller 
Ought  to  Have  Electric 
Lights  These  Days,  and 
to  Make  This  Dream  a 
Reality  an  Australian  In- 
ventor Has  Perfected  the  Practical  Wind-m 
namo  Plant  Here  Shown 


purposes  of  comparison  we  shall  term  as 
follows : 

The  small  plant  with  a  capacity  for  light- 
ing fifteen  16-candle  power  lights 
for  a  period  of  four  hours  per  day, 
and  a  storage  capacity  to  operate 
fifteen  16-candle  power  lights  for 
six  days  without  any  wind  at  all. 

The  large  plant  has  the  same 
specification  as  the  small  plant  ex- 
cept that  it  has  a  capacity  to  light 
twenty-five  16-candle  power  lights 
per  day. 

The  electricity  may  be  used  to 
operate  electric  fans,  electric  vacu- 
um cleaners,  sewing  machine  mo- 
tors, electric  pumps,  electric  toasters, 
and  small  electric  irons.  The  in- 
ventor has  adopted  twenty-five  volts 
as  standard  pressure.  The  storage 
battery  consists  of  14  cells  con- 
nected in  series.  This  insures  easy 
charging  from  the  dynamo,  as  there 
is  practically  no  resistance  in  the 
circuit. 

The  wind-motor  has  two  wind- 
wheels  as  will  be  observed,  one  be- 
ing a  little  larger  than  the  other. 
The  smaller  wheel  of  the  two  always 
faces  to  the  wind,  and  maintains  its 
position  in  front  of  the  larger  or 
back  wheel.  The  wind  first  presses 
against  the  vanes  of  the  smaller 
wheel,  and  starts  this  wheel  turning 
in  the  direction  of  the  hands  of  a 
clock.  The  whole  force  of  the  wind, 
however,  is  not  exhausted  on  the 
wheel,  but  a  part  of  the  wind  pres- 
sure passes  thru  to  the  back  wheel, 
and  again  is  turned  into  rotary  mo- 
tion. The  back  wheel  also  turns  in 
the  same  direction  as  the  hands  of  a 
clock.  The  two  wheels  are  on  sep- 
arated axles,  but  are  coupled  to- 
gether by  a  differential  gearing  in 
similar  fashion  to  the  back  axle  of 
a  motor  car.  This  differential  allows 
each  wheel  to  rotate  practically  as 
if  it  had  no  connection  with  the 
other,  and  in  this  way  brings  about 
an  excellent  equalizing  effect  and  a 
balance  of  power.    The  two  wheels 


pour  into  the  storage  battery,  and  con- 
tinues to  do  so  until  the  wind  pressure  fails. 
When  this  happens  the  electric  valve  im- 
mediately trips  and  disconnects  the  wire 
carrying  the  current,  thus  preventing  the 
electricity  from  escaping  back  thru  the 
dynamo.  The  above  operation  can  be 
likened  to  an  ordinary  windmill  driving  a 
pump,  and  pumping  water  from  a  well  into 
a  tank.  When  the  wind  fails  the  valve 
in  the  pump  closes,  and  prevents  the  water 
from  the  tank  running  back  into  the  well. 

The  operation  of  this  plant  is  claimed  to 
be  absolutely  automatic,  and  a  hand  is  not 
needed  near  it  for  six  months  at  a  time. 
In  high  winds  and  low  winds  alike,  all  ad- 
justments as  to  wind  direction,  speed,  turn- 
ing out  of  the  wind,  etc.,  are  made  auto- 
matically. The  application  of  the  gyro- 
scopic principle  ensures  that  the  mechanical 
operation  is  automatic. 

The  dynamo  is  a  special  and  original  de- 
sign, and  forms  the  supporting  base  for  the 
wind-motor  unit.  The  armature  is  of  pe- 
culiar shape,  being  much  longer  for  its 
diameter  than  usual.  This  feature  gives 
the  dynamo  its  remarkable  characteristic  of 
generating  electricity  at  exceptionally  slow 
speed.     (Continued  on  page  422) 


Output  of  Type  M  l  Fifteen 
Light  Plant 

in 

f  600 
•5  550 
>  500 
Z  450 
.  400 
■=>  350 
g:  300 
5  i50 
O  200 
150 
50 

i 

l    4   6  8    10  «   H   lb   18  iO  11  i<  li  IH  3D  X  34  36 

Wind  Pressure  in  Miles  per  Hour 

Typical  Electrical  Out- Put   Curve  for  15 
Light  Wind-Motor  Dynamo  Plant  at  Vari- 
ous Wind  Pressures. 

October,  1917 


THE  ELECTRICAL  EXPERIMENTER 


373 


New  Electro-Therapeutic  Apparatus 


X-Ray 

AT  the  convention  of  the  American 
Medical   Association   held   at  the 
Hotel  Astor  in  June  at  New  York 
^  City,  the  exhibit  of  electric  appa- 
ratus showed  many  interesting  new 
developments,  particularly  those  to  be  used 


Fig.  4.    A  New  Quartz  Mercury  Arc  Lamp 
For  Treating  Skin  Diseases. 


in  connection  with  hospitals  and  field  hos- 
pitals at  the  front. 

One  very  ingenious  X-ray  equipment  con- 
sisted of  a  portable  table  for  laying  the 
patient  upon  to  be  X-rayed;  the  outfit  also 
included  a  small  gasoline  engine  generating 
set,  a  closed  core  transformer,  this  trans- 
former being  used  in  connection  with  a 
regulating  device  to  operate  a  new*  type 
of  X-ray  tube.  This  tube,  about  four  inches 
in  diameter  (see  illustration,  Fig.  1),  had 
an  anode  terminal  of  solid  tungsten  metal 


By  H.  ROSENTHAL 

supported  on  a  rod  of  molybdenum  and  a 
cathode  consisting  of  a  tungsten  spiral, 
which  was  heated  electrically  from  a  low 
voltage  circuit  from  the  primary  of  the 
transformer.  The  X-ray  tube  suppresses 
any  current  in  the  direction  that  does  not 
make  the  hot  filament  cathode.  It  there- 
fore is  capable  of  rectifying  its  own  cur- 
rent. In  order  to  make  the  conditions 
stable  a  large  set  of  air  cooled  ventilating 
vanes  are  made  part  of  the  anode  of  the 
tube. 

The  gasoline  engine  unit  which  operates 
the  transformer  is  so  designed  with  an 
electrically  controlled  solenoid  that  it  can 
be  placed  some  distance  from  a  base  hospi- 
tal or  tent,  thus  eliminating  the  unpleasant 
noise.  The  entire  equipment  is  so  arranged 
as  to  be  portable  for  immediate  transporta- 
tion. 

X-Ray  Accessories 

Some  of  the  newer  developments  in  the 
accessories  to  be  used  in  connection  with 
X-ray  work  include  the  Hydrex  tube,  Fig. 
2.  This  tube  operates  on  the  principle  of 
having  an  auxiliary  chamber  filled  with 
hydrogen  and  sealed  from  the  top  by  a 
mechanically  operated  mercury  valve.  This 
valve  is  opened  by  drawing  the  mercury 
past  two  porous  blocks,  thereby  leaving  a 
passage  for  a  certain  amount  of  hydrogen 
to  enter  the  tube.    To  open  the  valve  a 


Fig.  6.  Small  Electrically  Heated  "Warm 
Stage"  for  the  Microscope. 


Fig.  7.    This  Miniature  Electric  Incubator  for 
Microscope  Stages  Enables  the  Physician  to 
Study  "Live"  Bacteria  Organisms. 


small  suction  pump  is  provided  and  is 
clamped  directly  on  to  the  glass  bowl,  or 
any  other  convenient  place,  so  the  rubber 
tube  can  be  attached 
to  the  hydrogen 
chamber.  To  lower 
the  vacuum  the 
plunger  is  pulled  out 
to  its  full  length 
and  released  imme- 
diately. To  raise  the 
vacuum  all  that  is 
necessary  is  to  dis- 
connect the  anode 
and  connect  it  to 
cathode  and  run  a 
weak  current  thru 
the  tube. 

Very  elaborate 
tables  of  new  devel- 
opment were  shown 
for  laying  the  pa- 
tient upon  and  so 
equipt  as  to  be  used 
either  for  examina- 
tion with  a  fluoro- 
scope  or  to  be  used 

directly  in  taking  Hydrogen  Thru  a 

X-ray  plates.  Hydrogen  Thru  a 


One  type  of  table  was  so  nicely  counter- 
balanced that  very  little  effort  was  needed 
to  obtain  almost  any  position  an  operator 
would  wish.  It  was  also  arranged  with 
a  small  motor,  foot  controlled,  which  would 
raise  the  table  or  lower  it  in  an  angular 
position,  according  to  the  will  of  the 
operator. 


Fig.  5.  A  Recent  Type  of  Anesthetizing  Ap- 
paratus, Driven  by-  a  Small  Electric  Motor. 


Another  type  of  table  was  fitted  with 
accessories  necessary  for  making  charts  of 
the  heart  and  lungs,  these  charts  or  tracings 
being  made  directly  by  examining  the  pa- 
tient with  a  fluoroscope  and  by  means  of 
an  automatic  device. 

A  duplicate  of  the  X-ray  equipment  sup- 
plied to  the  N.  Y.  Bellevue  Hospital  was 
also  shown,  being  the  largest  X-ray  plant 
in  the  United  States. 

(Continued  on  page  421) 


Mercury  Valve.  Vacuum  Is  Adjustable. 
Mercury  Valve  Vacuum  Is  Adjustable. 


374 


THE  ELECTRICAL  EXPERIMENTER 


October,  1917 


ELECTRIC  FAN  EXCELLENT  FOR 
DRYING  FRUIT. 

Cheap  living  and  plenty  of  it;  wide  va- 
riety; wholesome,  clean,  nourishing  food; 
prepared  quickly  with  little  labor  and  trou- 
ble in  your  own  home — by  your  own  hands  ! 

An  electric  fan  and  a  kitchen  knife  are 


immediately  at  a  cost  of  about  $4,000,000 
and  that  water  power  would  not  be  used. 

Informally  officials  explained  that  the 
announcement  did  not  mean  that  the  idea 
of  building  a  water-power  nitrat  plant  had 
been  permanently  abandoned,  although  it 
would  not  be  pressed  at  present.  Several 
years  would  be 
required  to 
build  the  enor- 
mous plant  re- 
quired for  the 
utilization  of 
water  power, 
and  for  that  rea- 
son it  was  de- 
termined that 
for  urgent  war 
purposes  it 
would  be  neces- 
sary to  adopt 
one  of  other 
processes  of  pro- 
ducing nitrats. 


New 


the  Electric 
Which  to 


Fan  In  Drying  Fruit. 
Help  Win  the  War. 


Another  Way 


HOW  TROL- 
LEY MOTOR- 
MEN  LEARN 
THEIR  DU- 
TIES. 


the  only  "tools"  necessary.  Drying  can  be 
done  in  home-made  box  trays,  a  table  top, 
sheet,  strings  (apples,  pears,  etc.),  and 
dozens  of  other  ways.  Just  like  grand- 
mother did,  only  quicker,  cleaner  and  bet- 
ter tasting! 

The  U.  S.  Department  of  Agri- 
culture says  (Bulletin  No. 
841)  :  "The  fan  method  has 
a  marked  advantage  in  that 
the  product  keeps  cool,  owing  to 
evaporation  while  it  is  being  dried, 
thus  tending  to  retain  the  color 
and  eliminate  spoilage." 

Almost  all  the  vegetables  and 
fruits  can  be  treated  and  stored 
away — even  the  most  juicy,  like 
tomatoes.  And  besides — this  new 
way  of  drying  eliminates  the  big- 
gest part  of  the  work.  It  does 
away  with  a  lot  of  canning — and 
that's  good,  for  jars  and  contain- 
ers are  very  scarce  and  mighty 
high  in  price. 

All  summer  long,  at  odd  times, 
the  housewife  can  pick  up  choice 
bargains  at  the  markets,  prepare 
them  in  a  few  minutes,  and  the 
drying  goes  on  while  she  attends 
to  something  else.  By  cold 
weather  time  she  can  have  her 
home  stocked  up  like  a  siege  fort 
— for  the  longest,  hardest  kind  of 
a  cold,  long  winter. 

A  THOUSAND  AUTOMATIC  TELE- 
PHONES ORDERED  FOR  AUS- 
TRALIA. 

Orders  aggregating  1,000  lines  of  auto- 
matic central  office  equipment  and  1,000 
telephones  equipt  with  the  dial,  have  just 
been  placed  to  be  used  as  additions  to  the 
automatic  exchanges  in  Australia.  This  is 
the  second  such  order  placed  since  the  be- 
ginning of  1917,  the  first  one,  for  1,800 
lines,  being  received  in  February. 

The  progress  of  the  automatic  in  Aus- 
tralia has  been  most  rapid.  Only  five  years 
ago  there  was  a  single  1,100-line  exchange 
in  operation,  at  Geelong.  Today  there  are 
nearly  a  score  of.  exchanges  and  a  total  of 
practically  35,000  lines  of  automatic  equip- 
ment in  service  thruout  the  commonwealth. 
No  "central"  is  required  and  thus  misun- 
derstandings are  eliminated. 

U.  S.  TO  SPEND  $4,000,000  FOR  NI- 
TRAT PLANT. 

Secretary  Baker  has  announced  that  a 
plant  for  the  production  of  nitrats  from 
atmospheric  nitrogen  would  be  constructed 


By  the  time  an  applicant  for  the  position 
of  motorman  or  conductor  on  the  Brooklyn 
Rapid  Transit  System  has  past  thru  their 
school  for  employees  he  has  had  it  brought 
home  to  him  that  a  man  must  have  at  least 
the  qualifications  of  good  character,  a  clean 


rate  detail  of  the  mechanical  equipment 
from  which  the  men  receive  their  instruc- 
tion, are  most  impressive;  and  the  entire 
array  of  massive  and  handsome  exhibits, 
while  attracting  and  holding  the  interest, 
might  seem  to  defy  the  layman's  under- 
standing. 

Here  spread  out  before  you  are  the  vitals 
of  the  trolley  car,  dissected  and  labeled. 
(See  accompanying  illustrations.)  No  de- 
tail is  left  in  darkness  or  obscurity.  All  is 
revealed.  Even  the  little  boy  who  for  years 
has  yearned  to  crawl  under  a  car  to  see 
what  it  looks  like  inside  would  be  satisfied. 
For  in  very  truth  he  would  see  one  turned 
upside  down,  and  working  just  the  same  in 
spite  of  the  awkwardness  of  this  position, 
as  a  turtle  sometimes  keeps  on  working 
when  you  turn  it  over  on  its  back.  Be  he 
schoolboy  or  grown  man,  any  visitor  would 
enjoy  a  trip  around  the  motormen's  room 
with  one  of  Instructor  Duffy's  classes. 

Emphasis  is  laid  on  the  regular  inspection 
of  his  car  which  a  motorman  is  required  to 
make  before  going  on  the  road,  special  at- 
tention being  called  to  the  life  guard,  by 
which  about  ninety  per  cent,  of  persons 
knocked  down  by  the  front  of  a  car  have 
been  saved. 

Every  part  of  the  equipment  is  in  its 
standard  location,  many  of  them  bearing 
metal  signs  to  accustom  the  men  to  calling 
things  by  their  right  names.  Fare  col^ 
lection,  door  operation,  buzzer  signals, 
thermostat  control  of  heaters,  use  of 
switches,  replacement  of  fuses,  etc.,  are 
also  demonstrated.  The  use  of  the  electric 
automatic  track  switch  is  taught  in  connec- 
tion with  the  center  entrance 
car,  switch  levers,  semaphores 
and  lights  all  working  just  as 
they  would  in  actual  service. 

Step  by  step  the  men  in  the 
schoolroom  become  familiar 
with  the  elaborate  mechanism 
that  passes  into  their  keeping 
when  hand  and  controller 
meet.  The  "demonstration 
board,"  which  shows  the 
course  of  the  current  and  the 
operation  of  the  control  from 
trolley  wire  to  rail,  is  a  toy 
which  could  not  fail  to  fas- 
cinate any  human  being  be- 
tween the  ages  of  six  and 
sixty.  When  this  board  has 
been  explained  to  him  the  stu- 
dent has  a  remarkably  clear 
idea  of  how  the  electric  cur- 
rent operates  and  how  it  is 
controlled. — Photos  courtesy 
B.  R.  T.  Monthly. 


new 
when 
dent 
B.  R. 


record,  good 
health  and  a  pre- 
sentable appear- 
ance before  he  is 
even  given  a 
trial. 

This  frame  of 
mind  receives  a 
impulse 
the  stu- 
enters  the 
T.  Surface 
School  Room, 
for  here  he  finds 
himself  in  a  place 
where  there  is 
manifestly  much 
to  learn — more, 
perhaps,  the 
average  appli- 
cant might  feel 
at  first  glance, 
than  he  could 
ever  hope  to 
learn.  The  in- 
tricacv  and  elabo- 


Two  Views  of  the  Brooklyn  Rapid  Transit  Company's  School  for  Motormen. 
Every  Part  of  a  Trolley  Car  Is  Dissected  and  Demonstrated  In  Working 

Condition. 


October,  1917 


THE  ELECTRICAL  EXPERIMENTER 


375 


WOMEN  AND  ELECTRICITY. 

When  a  woman  is  sulky  and 

will  not  speak   Exciter. 

If  she  gets  too  excited   Controller. 

If  she  talks  too  long.   Interrupter. 

If  her  way  of  thinkin  :  is  not 

yours    Converter. 

If  she  is  willing  to  conic  half 

way  •   Meter. 

If  she  will  come  all  the  way  Receiver. 

If  she  wants  to  go  further..  Conductor. 

If  she  would  go  still  further  Dispatcher. 

If  she  wants  to  be  an  angel.  Transformer. 

If  you  think  she  is  unfaithful  Detector. 

If  she  is  unfaithful   Lever. 

If  she  proves  your  fears  are 

wrong    Compensator. 

If  she  goes  up  in  the  air...  Condenser. 

If  she  wants  chocolates....  Feeder. 

If  she  sings  wrong   Tuner. 

If  she  is  in  the  country   Telegrapher. 

If  she  is  a  poor  cook   Discharger. 

If  her  dress  unhooks   Connector. 

If  she  eats  too  much   Reducer. 

If  she  is  wrong   Rectifier. 

If  she  is  cold  to  you   Heater. 

If  she  gossips  too  much.  .  .  .  Regulator. 

If  she  fumes  and  sputters.  . .  Insulator. 

If  she  becomes  upset   Reverser. 


AUTO  SCHOOL  HAS  ELECTRIC 
DYNAMOMETER. 

One  of  the  leading  auto  schools  of  the 
west  has  installed  in  its  testing  laboratory 
the  modern  electric  dynamometer  here  illus- 
trated. The  students  are  thus  enabled  to 
make  very  accurate  tests  on  any  type  of 
gasoline  engine  with  regard  to  the  horse- 
power output  and  other  characteristics. 
The  electric  dynamometer  represents  the 
highest  form  of  prime  mover  testing  device 
available  to-day.  The  dynamo  unit  is  mov- 
ably  swung  in  substantial  pedestal  bearings 
as  shown,  the  turning  effort  of  the  engine 
connected  to  it  for  test  being  indicated  on 
suitable  scales  and  electrical  indicating  in- 
struments. 

Aeroplane  engines  are  now  tested  by  a 
similar  apparatus.  No  guess  work  enters 
the  tests  as  carried  out  with  the  dyna- 
mometer, the  results  being  accurate  to  with- 
in a  fraction  of  a  per  cent.  There  will  be 
a  very  large  demand  for  engine  drivers  and 
experts  this  Fall. 


TELEGRAPHER    LIFTS    OVER  20 
TONS  PER  NIGHT. 

J.  H.  Johnson,  an  Associated  Press  oper- 
ator in  Boston,  while  working  at  Man- 
chester, N.  H.,  a  year  ago,  devised  an  in- 
genious method  of  determining  the  amount 
of  work  performed  by  him  in  one  night, 


BRANDING  ORANGES  BY  ELEC- 
TRICITY. 
By  Harold  J.  Wood. 

ONE  of  the  newest  wrinkles  under  the 
sun  is  the  idea  of  branding  oranges, 
lemons  and  apples  to  protect  them 
from  the  unscrupulous  methods  of  fruit- 


The  Fruit  Growers  Have  Solved  the 
Problem  of  Indelibly  Marking  Their 
Brands  by  Means  of  An  Electrically 
Heated  Revolving  Die.  It  Brands  Two 
Carloads  of  Oranges  Per  Day. 


exprest  in  mechanical  terms  says  Telegraph 
and  Telephone  Age.  By  rigging  tip  a  postal 
scale  in  a  special  manner  he  found  it  re- 
quired a  pressure  of  ten  ounces  on  the  type- 
writer keys  to  print  each  letter,  and  in  the 
course  of  a  night,  with  an  average  report 
of  14,000  words,  allowing  five  letters  to  a 
word,  the  total  pressure  exerted  would  lift 
700,000  ounces,  or  21%  tons. 

This  computation  was  the  result  of  a  dis- 
cussion which  arose  in  the  office  of  the 
Manchester  paper  as  to  which  man  on  the 
paper  worked  the  hardest. 

The  award  was  made  to  another  man,  but 
Mr.  Johnson,  not  being  satisfied  with  it, 
made  the  investi- 
gation of  his  own 
work  on  his  own 
account,  with  the 
result  that  he  was 
declared  to  be  the 
hardest  worker  in 
the  office.  And  yet 
they  do  say  truck 
drivers  are  the 
only  men  that  do 
real  work ! 


fhoto  Courtesy  of  Michigan  male  Auto  ejnhuul. 


The  Electric  Dynamometer  In  Use  for  Testing  Horse-power  of  Gaso- 
line Engine  In  the  Laboratory  of  Progressive  Western  Auto  School. 


WIRELESS 
PLOT  IN 
ARGENTINA. 

A  secret  wireless 
station  has  been 
discovered  on  the 
coast  of  the  terri- 
tory of  Chubut  by 
the  Argentine  Na- 
vy Department. 

The  authorities 
believe  the  station 
was  to  be  used 
in  communicating 
with  suspicious 
vessels. 


stand  men  in  many  parts  of  the  country. 
L.  Ahlberg,  an  Alaskan,  has  invented  a 
machine  which  brands  fruit  by  electricity. 
The  California  Fruit  Growers  Exchange 
has  bought  an  option  on  the  exclusive  rights 
for  the  use  of  the  machine  in  connection 
with  shipments  of  "Sunkist"  citrus  fruits 
to  all  parts  of  the  United  States,  Canada, 
England  and  Ausralia. 

The  machine  can  be  used  in  branding 
any  fruit  that  has  a  waxy  skin.  It  will 
brand  oranges,  lemons,  apples,  pears,  water- 
melons and  cucumbers.  The  device  con- 
sists of  a  big  wheel  with  18  spokes  in  it. 
At  the  end  of  each  spoke  is  a  shoe  in  which 
there  is  a  die  which  stamps  the  name  of 
the  fruit  into  its  cheek.  As  the  wheel  re- 
volves, a  small  nipple  at  the  top  drops  a 
little  ink  upon  each  die,  and  a  felt  wheel 
distributes  it.  An  automatic  device  turns 
on  the  electricity  or  shuts  it  off  whenever 
the  temperature  of  the  die  rises  above  or 
drops  below  a  certain  point.  The  dies  are 
prest  down  upon  the  fruits  as  they  are 
carried  along  beneath  the  wheel  on  an  end- 
less belt  of  metal  saucers,  and  each  die 
makes  its  hot  imprint  into  the  cheek  of 
the  fruit. 

The  heat  of  the  die  melts  the  wax  in 
the  skin  of  the  fruit,  causing  it  to  flow 
into  the  imprint  of  the  die  and  fill  up  any 
breaks  which  might  be  made  in  the  skin, 
at  the  same  time  taking  up  the  ink  from 
the  face  of  the  die. 

Citrus  growers  in  Southern  California, 
where  the  machine  has  been  operated  in 
packing  houses  on  an  experimental  basis 
for  twenty  months,  declare  that  it  gives 
absolute  satisfaction.  It  is  capable  of 
branding  two  carloads  of  oranges  or  lemons 
per  day. 


AMONG  the  hundreds  of  new  devices  and  appliances  publisht  monthly  in  The  Electrical  Experimenter,  there  are  several,  as 
a  rule,  which  interest  you.    Full  information  on  these  subjects,  as  well  as  the  name  of  the  manufacturer,  will  be  gladly 
furnisht  to  you,  free  of  charge,  by  addressing  our  Technical  Information  Bureau 


376 


THE  ELECTRICAL  EXPERIMENTER 


October,  1917 


Unique  Revolving  Dancing  Floor 


Do  you  like  to  dance?  Well,  here's  a  new 
one  in  gay  New  York  that  has  the  old- 
fashioned  "barn  dance"  of  our  grand-dads 
beat  forty  ways. 


gages  this  rack.  The  shaft  is  connected 
thru  numerous  reduction  gears  and  at- 
tached to  a.  %  horse-power  electric  motor 
which  slowly  revolves  the  floor ;  not  faster 


CHROMIUM  STEEL  PERMANENT 
MAGNETS. 

An  investigation  into  the  suitability  of 
chromium  steel  for  permanent  magnets  has 
recently  been  carried  out  in  Germany  and 
reported  upon  to  the  Physikalische-Tech- 
nische  Reichsanstadt.  Figures  are  given  for 
five  bars  of  chromium  steel,  these  being 
compared  with  five  bars  made  of  tungsten 
steel,  the  product  of  remanence  and  coercive 
force  being  taken  as  a  criterion  of  quality. 
The  remanence  of  the  chrome  steel  bars 
was  further  tested  under  20  hours'  heat- 
ing at  100° C,  six  heatings  up  to  100°  C.  and 
20  falls  from  a  height  of  2j^  metres  on  to 
a  wooden  block.  It  is  concluded  that  care- 
fully prepared  chromium  steel  is  a  suitable 
substitute  for  tungsten  steel. 


A  New  York  Restaurant  Has  Provided  a  Real  Novelty  for  Its  Patrons  in  a  Re- 
volving Dancing   Floor.     An  Electric  Motor  In  the  Basement  Turns  It  Slowly 
While  the  Diners  Enjoy  the  Novel  Sensation. 


When  you  are  in  town  don't  fail  to  take 
a  trip  to  Murray's,  one  of  the  city's  show 
places  and  cabarets,  where  between  courses 
you  may  dance,  dine  and  wine  with  your 
partner  upon  a  floor  that  slowly  revolves 
neath  your  feet,  giving  a  pleasing  and  novel 
sensation  as  you  whirl  to  the  strains  of 
the  Jazz  Band. 

In  the  center  of  the  revolving  floor  is  a 
circle  of  beautifully  colored  glass,  under 
which  are  myriads  of  lights  and  as  one 
whirls  around,  flickering  shadows  are  cast 
upon  the  dancers. 

The  writer,  who  did  not  know  about  the 
revolving  floor  feature,  one  day  last  month 
visited  this  restaurant  and  took  a  seat  at 
one  of  the  tables  placed  at  the  circumfer- 
ence of  the  revolving  floor.  At  another 
table  two  feet  away,  but  on  terra  firma,  he 
noticed  an  acquaintance.  A  few  pleasan- 
tries were  exchanged,  whereupon  the  writer 
buried  his  face  in  the  voluminous  bill-of- 
fare.  It  took  several  minutes  to  decipher 
the  French  dishes  et  al,  after  which  he  ad- 
drest  a  few  more  words  to  his  ac- 
quaintance, not  taking  the  precaution  to 
look  at  him  first.  "Sir,  how  dare  you!" 
spoke  up  an  angry  looking  female,  at  the 
spot  where  the  acquaintance  was  supposed 
to  sit,  but  alas,  sat  no  more !  You  see 
the  floor  had  revolved  smoothly  and  sil- 
ently some  six  feet,  and  the  writer's  ac- 
quaintance was  now  that  far  behind !  It 
took  the  writer  a  few  seconds  to  realize 
what  had  happened,  and  the  expression  on 
his  face  while  apologizing  to  the  insulted 
damsel,  must  have  been  anything  but  in- 
telligent. 

Now  to  let  the  reader  in  on  how  all  this 
is  done — Presto.  The  floor  is  on  a  pivot 
under  which  are  numerous  wheels  care- 
fully set  and  oiled  so  as  not  to  make  any 
sound  when  the  floor  is  movinsr.  Along 
the  outer  edge  of  the  floor  (which  is  really 
a  large  disc  twenty-five  feet  in  diameter) 
is  a  toothed  rack  carefully  concealed  un- 
der the  flooring.  A  pinion  on  a  shaft  that 
passes  thru  the  floor  to  the  basement  en- 


than  one  complete  revolution  every  half 
hour.  By  referring  to  the  sectional  diagram 


How  Electric  Motor  Rotates  Novel  Dancing 
Floor. 

a  good  idea  of  the  mechanism  may  be  ob- 
tained.   

A  gasoline  engine  driven  dynamo  that 
is  entirely  automatic  in  its  action  is  at- 
tracting attention  in  England. 


ELECTRICITY  FROM  THE  WIND. 

The  electrical  engineering  department  of 
the  State  Agricultural  College  of  Manhat- 
tan, Ks.,  is  at  present  engaged  in  conduct- 
ing a  series  of  experiments  with  a  view  to 
improving  the  prevailing  methods  of  gen- 
erating electricity  from  windmill  power.  In 
the  present  test  the  generator  is  mounted 
on  the  head  of  the  mill  and  geared  directly 
to  the  source  of  power,  instead  of  being 
belted  to  the  mill  at  its  base,  as  is  usually 
the  practise.  The  main  need  at  present 
seems  to  be  a  mill  that  requires  a  lower 
wind  velocity  to  start  those  now  available 
since  the  latter  are  idle  for  long  periods  at 
a  stretch,  and  therefore  necessitate  the  em- 
ployment of  large  storage  batteries. 


NOVEL  MEDICAL  COIL  IS  CON- 
TAINED IN  HANDLES. 

The  accompanying  illustration  shows  one 
of  the  latest  electro-medical  coils  which  is 
extremely  compact  as  will  be  evident.  The 
small  induction  coil,  as  well  as  the  dry  bat- 
tery and  regulating  attachment,  are  all  built 
into  the  tubular  electrode  handles  which 
are  connected  together  by  a  flexible  con- 
ductor. 

To  use  the  apparatus  the  patient  has  but 
to  hold  the  two  electrodes  in  the  hands  and 
by  pressing  a  small  sliding  switch  on  one 
of  the  electrodes,  the  current  is  turned  on. 
The  strength  of  the  current  may  be  in- 
tensified by  means  of  a  sliding  tube  pro- 
jecting from  one  of  the  handles.  If  it  is 
desired  to  apply  the  current  by  means  of 
a  dampened  sponge  electrode,  then  this  de- 
vice is  inserted  in  a  socket  on  one  of  the 
handles,  and  the  current  may  then  be 
switched  on  to  the  sponge  instead  of  to 
the  handle  shell  by  depressing  a  switch  but- 
ton provided  for  the  purpose.    The  com- 


This,    Laical   luea    in    Compact    Electro- Meuical   Coils   Comprises   a    Small    Induction  Coil, 
Switches  and  Battery,  Which  Are  All  Contained  Within  the  Two  Electrode  Handles. 


The  United  States  Bureau  of  Standards 
has  developed  a  delicate  thermo-electric 
test  for  the  purity  of  platinum. 


plete  outfit  is  very  neat  in  appearance,  and 
a  new  dry  battery  can  be  replaced  in  a  few 
seconds. 


October,  1917 


THE  ELECTRICAL  EXPERIMENTER 


377 


SCRUBBING  BY  ELECTRICITY. 

The  applications  of  electricity  for  re- 
lieving both  man  and  woman  of  tedious 
work  and  drudgery  are  gradually  being  ex- 
tended. One  of  the  most  irksome  duties 
connected  with  the  keeping  tidy  of  large 
buildings  and  institutions,  is  the  scrubbing 
of  floors.  Not  only  is  this  a  laborious  and 
disagreeable  task,  but  it  takes  a  great  deal 
of  time  to  go  over  a  large  surface  of  floor- 
ing with  scrub  brush  or  even  with  a  mop. 

The  solution  of  this  problem  is  the  elec- 
trically driven  floor  scrubbing  machine. 
A  device  of  this  character  which  has  been 
tried  out  and  found  very  satisfactory  is 
illustrated  herewith.  The  machine  is  en- 
tirely self-contained  and,  considering  its 
large  capacity,  is  quite  compact.  Its  di- 
mensions are  28  inches  long,  20  inches 
wide,  16  inches  high.  The  weight  of  the 
outfit  is  100  pounds.  The  entire  machine 
is  made  of  metal  except  the  revolving 
brush.  The  upper  portion  of  the  machine 
consists  of  a  tank  for  holding  clean  water. 

The  machine  wets,  sweeps,  scrubs  anc1 
dries  the  floor  at  a  single  operation.  It 
requires  only  a  single  attendant  who  mere- 
ly pushes  the  machine  forward  and  guides 
it.  He  controls  the  amount  of  water  dis- 
tributed on  the  floor  by  means  of  tht 
handle.  This  water  is  immediately  swept 
up  by  the  cylindrical  brush  which  is  16 
inches  wide  and  has  a  circumference  of  1Z 
inches.  This  brush  is  driven  by  a  one- 
fourth  horsepower  motor  thru  a  silent 
chain  and  sprocket  so  that  the  brush  re- 
volves at  about  600  revolutions  per  min- 
ute. The  brush  does  the  actual  scrubbing 
and  carries  all  of  the  dirt  and  soiled  water 
over  an  apron  into  a  separate  receiving 
pan  so  the  scrubbing  is  always  done  with 
clean  water  from  the  upper  tank.  An  up- 
right is  attached  to  the  machine  which 
carries  a  cord  reel  at  the  top  to  permit  of 
taking  in  and  letting  out  the  cord  by  means 
of  which  it  is  connected  to  any  ordinary 
lighting  outlet. 


rate  of  one  mile  per  hour,  it  will  scrub  an 
area  of  nearly  7,000  square  feet  per  hour. 
This  is  about  ten  times  as  much  floor  area 
as  an  experienced  janitor  can  scrub  clean 
in  the  the  same  length  of  time.  Not  only 
has  this  machine  exceptional  capacity,  but 
it  leaves  the  floor  much  cleaner  and  more 
evenly  scrubbed  than  can  be  done  by  hand. 

Naturally  the  greatest  field  for  a  ma- 
chine of  this  type  is  in  cleaning  corridors, 
halls  and  large  rooms  in  public  buildings, 
office  buildings,  etc.  In  such  places  the 
janitor  work  is  usuallv  done  at  night.  Be- 
cause the  machine  cleans  the  floors  so 
rapidly,  it  results  also  in  considerable  sav- 
ing in  current  used  for  lighting  the  prem- 
ises during  cleaning. 

LET    THE    ELECTRIC  LIGHTED 
KEY-HOLE  FIND  THE  WAY. 

The  annoyance  of  groping  about  blindly 
for  the  keyhole  on  cold  (or  "large  sized" 
evenings)  nights  will  become  a  thing  of  the 
past  if  the  invention  illustrated  here  comes 
into  general  use.  The  device  is  that  of  an 
Ohio  man.    By  pushing  a  button  on  the 


A  NOVEL  ELECTRIC  CIGAR 
LIGHTER. 

The  accompanying  illustration  shows  a 
new  tvoe  of  electric  cigar  lighter  for  use  in 


Blank 


Blank 


Where  in 


Is  That  Keyhole?!!    Push  the  Button  in  This 
Electric  Knob  Device  and  the  Keyhole  Be- 
comes Instantly  Illuminated. 

door  knob  a  small  electric  light  just  above 
the  keyhole  is  flashed  on  and  finding  the 
keyhole  then  is  an  easy  task. 


A  i/4  H. 
Building 

This 
pacity. 
tendant 


ELECTRIC  DRIVE  FOR  BATTLE- 
SHIPS "COLORADO"  AND 
"WASHINGTON." 

Contracts  totaling  approximately  $2,000,- 
000  have  been  placed  recently  with  the 
Westinghouse  Electric  &  Mfg.  Company, 
by  the  New  York  Shipbudding 
Company,  for  furnishing  the 
necessary  electrical  equipments 
for  the  propulsion  of  the  new 
Superdreadnaughts  •'Colorado" 
and  "Washington." 

The  equipments  to  be  fur- 
nished are  practically  duplicates 
of  that  contracted  for  by  the 
Navy  Department  for  the  U.  S. 
S.  "Tennessee,"  now  building 
at  the  New  York  Navy  Yard. 
The  four  propellers,  as  in  the 
case  of  the  "Tennessee,"  in- 

P.  Electric  Scrubbing  Machine  for  Use  In  Large  **stead    °*  fbejn.g- 
s  and  Halls.    It  Reels  Up  or  Unreels  Its  Electric     connected  to  driving  engines  or 
Supply  Cable  as  It  Goes  Along.  i  turbines,  are  to  be  driven  by 

machine  has  an  extraordinary  ca-  individual  motors.  The  current  for  the 
It  has  been  found  that  if  the  at-  motors  will  be  furnished  by  two  turbine 
pushes   the   outfit   forward   at   a  generators. 


"'1 


An  Electric  Spark  Ignites  a  Wick 
Soaked  with  Gasoline  in  This  Cigar 
Lighter.  It  May  Be  Operated  by  Bat- 
teries or   From  the   Lighting  Circuit. 


cigar  stores,  or  for  private  use.  This  de- 
vice can  be  operated  either  from  a  lighting 
circuit  or  from  batteries  placed  within  the 
box  supporting  the  lighter.  This  lighter 
insures  a  continuous  stream  of  sparks  which 
flow  to  the  wick  until  it  takes  fire.  The 
amount  of  electrical  energy  consumed  for 
this  purpose  is  very  small.  The  only  oper- 
ating expense  is  the  cost  of  1  gallon  of  gas- 
oline for  feeding  the  wick.  For  this  pur- 
pose 1  gallon  of  gasoline  will  last  a  full 
year.  When  used  with  batteries,  a  special 
control  lever  allows  the  device  to  use  cur- 
rent only  when  the  lighter  is  in  actual  use. 
This  feature  reduces  the  current  consump- 
tion to  a  minimum.  In  case  of  wear  or  in- 
jury, any  part  of  the  lighter  can  be  readily 
replaced  at  moderate  cost. 

In  addition  to  the  main  generating  equip- 
ments and  propelling  motors,  the  contracts 
include  auxiliaries  for  the  main  turbine 
generators  and  smaller  auxiliary  turbine 
generators  for  supplying  light  and  power 
thruout  the  ships.  A  multitude  of  electric 
motors  will  also  be  utilized  for  doing  near- 
ly all  the  work  on  board  from  raising  the 
anchor  to  steering. 

60,000  COPIES  "E.E." 
are  now  sold  every  month  on  the  principal 
news-stands  in  the  U.  S.  and  Canada ;  and 
over  5,000  readers  are  disappointed  every 
month  because  the  news-dealer  says :  "Sold 
out!"  How  often  did  it  happen  to  you? 
Why  not  order  a  copy  from  the  news- 
dealer NOW?  It  costs  you  nothing  to  do 
so,  and  your  copy  will  be  waiting  for  you 
next  month. 

The  greatest  15c  worth  in  the  U.  S. 


Intercommunicating  telephones,  electric 
lights,  call  bells,  and  a  complete  fire  alarm 
system  are  installed  in  modern  farm  build- 
ings on  the  estate  of  a  wealthy  Long  Isl- 
ander. 


375 


THE  ELECTRICAL  EXPERIMENTER 


October,  1917. 


AN  ELECTRICAL  BROACH  WRAP- 
PER FOR  DENTISTS. 

For  over  fifty  years,  the  treatment  of 
root  canals  has  been  a  nightmare  to  care- 
ful and  conscientious  dentists.  Recent 
scientific  investigation  shows  that  the  dan- 
ger from  the  sort  of  .treatment  still  in 
vogue  among  99  per  cent  of  operators,  and 
the  distress  and  mortality  resultant  from 
carelessness,  improper  methods,  crude  and 
inefficient  instruments,  are  little  short  of 
appalling  and  certainly  de- 
plorable. To  make  root- 
canal  operations  a  success 
the   canal   must   be  ade- 


Dr.  Funk  and  His  Newly  Invented  Electrical 
Broach  Wrapper  for  Dentists  which  Bids  Fair  to 
Save  Many  Lives  Annually  by  the  Antiseptic 
Conditions  It  Brings  About.  It  Ensures  a  Per- 
fectly Clean  Broach  for  Every  Patient. 


quately  enlarged  to  permit  thoro  cleansing, 
which  means  that  every  vestige  of  dead 
nerve  and  bacteria,  which  is  liable  to  be 
present,  must  be  removed  and  the  canal  be 
perfectly  filled,  the  most  difficult  part  of  the 
entire  operation  being  the  removal  of  debris 
under  aseptic  conditions. 

The  only  method  by  which  root  canals 
can  be  cleansed  is  purely  mechanical  and 
consists  of  wrapping  cotton  on  steel 
needles,  which  have  a  fork  or  notch  on  the 
end.  The  notch  is  very  important,  other- 
wise the  cotton  would  slip  up  on  the  shank 
of  the  needle  and  the  cleansing  cotton 
would  not  reach  the  base  of  the  root,  there- 
by leaving  it  uncleansed  so  that  purifica- 
tion would  sooner  or  later  take  place,  sub- 
sequently forming  an  abscess,  which  is 
liable  to  cause  distressing,  if  not  fatal  di- 
sease, such  as  rheumatism,  heart  trouble, 
neuritis,  blindness,  insanity,  and  a  host  of 
other  constitutional  ills. 

The  old  method  of  wrapping  treating 
cotton  on  dental  needles  was  accomplished 
by  twisting  it  on  the  needle  with  the  fin- 
gers; this  is  an  uncleanly  and  dangerous 
procedure,  the  cotton  being  contaminated 
with  dead  cuticle,  perspiration,  and  any 
germs  that  may  have  been  present  on  the 
fingers  of  the  operator. 

Assuming  there  are  40,000  dentists  in 
the  United  States,  six  patients  per  dentist 
per  day,  240.000;  three  hundred  days  per 
year,  72,000,000  sittings :  five  applications 
per  sitting,  360,000,000,  to  be  conservative, 
divide  this  by  two,  180,000,000.  If  one  cares 
to  be  ultra-conservative,  halve  it  again, 
90,000,000  and  re-halve  it  if  you  please, 


leaving  45,000,000  chances  of  infection  due 
to  digital  contamination.  This  should  still 
be  sufficient  reason  to  strive  for  safer  and 
better  methods.  Many  attempts  were 
made  to  produce  an  effi- 
cient machine  for  wrap- 
ping needles,  and  given  up 
in  despair.  It  seemed,  for 
a  time,  to  be  a  mechanical 
impossibility  to  distribute 
microscopic  threads  of 
cotton  on  a  hair-like  needle 
suitable  for  den- 
tal purposes. 
However,  after 
years  of  experi- 
menting, Dr.  L. 
L.  Funk  has  fi- 
nally succeeded 
in  perfecting  a 
machine  that  ac- 
complishes the 
work  in  a  most 
perfect,  sa- 
tisfactory 
and  sanitary 
manner  ;  tl i e 
cotton  at  no 
time  coming  in  contact  with  the  fin- 
gers of  the  operator.  The  machine 
is  self  sterilizing  and  there  can  be  no 
chance  of  infection  due  to  faulty 
mechanism,  since  materials  do  not 
come  in  contact  with  germs  during 
the  process  of  wrapping,  sterilizing 
would  seem  unnecessary ;  however, 
on  the  principle  of  safety  first,  last, 
and  always,  the  machine  is  nrovided 
with  five  sterilizers,  practically  every 
method  known  to  science,  to  be  used 
in  conjunction  with  the  wrapper.  The 
machine  is  simple  to  operate.  A  child 
ten  years  of  age  with  ordinary  in- 
telligence can  wrap  broaches  more 
quickly  and  perfectly  than  it  can  pos- 
sibly be  done  by  hand. 

In  view  of  the  awful  carnage  now 
rampant  thruout  the  world,  and  from 
a  humanitarian  standpoint  I  desire  to 
offer  what  service  I  can,  con- 
sistently, to  the  United  States 
Government,  by  donating  these 
Broach  Wrappers  to  be  used  in  Government 
Infirmaries,  says  Dr.  Funk,  with  the  hope 
of  at  least  preserving  one  life  for  every  life 
destroyed  in  battle. 


A    MOTOR    THAT    RUNS  UNDER 
WATER. 

The  accompanying  photograph  shows  a 
sturdy  3^4  horsepower  electric  motor  run- 
ning under  water.  This  motor  was  first 
put  under  water  in  September,  1909,  at  a 
Machinery  Exhibition  in  Cleveland,  where 


H.P.   Electric   Motor  Running  Under 
Water. 

it  attracted  such  great  attention  that  it  was 
decided  upon  as  a  sort  of  trade  mark  for 
the  manufacturers. 

The  motor  has  repeatedly  been  used  in 
installations  where  it  is  subject  to  condi- 


tions fully  as  severe  as  this.  One  salt 
works  in  Cleveland  has  had  a  number  of 
these  motors  in  operation  for  over  ten 
years,  and  the  wet  salt  has  caked  into  the 
windings,  until  they  are  scarcely  visible : 
still  there  has  been  no  motor  failure  in  all 
this  time.  It  takes  a  particularly  husky  and 
well-built  motor  to  withstand  any  such 
treatment  as  this. 


A  MOTOR-DRIVEN  COMMUTATOR 
RECTIFIER. 

The  rectifier  shown  in  the  accompanying 
illustration  is  designed  for  the  charging 
of  small  storage  batteries,  such  as  used 
with  automobile  ignition,  lighting  and 
starting  sets.    The  single-circuit  type  is  a 


One  of  the  Jobs  We  All  Hate  to  Tackle 
Is  Charging  Storage  Batteries.  In  This 
Simple  Automatic  Device  a  Motor  Drives 
a  Commutator  in  Such  a  Way  that  the 
Alternate  +  and  —  A.  C.  Pulses  Are 
All  Rectified  or  Converted  into  Direct 
Current. 

self-contained  charging  plant  that  will 
charge  from  one  to  five  batteries  (or  up 
to  a  total  of  fifteen  cells).  By  keeping  the 
rectifier  running  twenty-four  hours  a  day 
and  taking  out  each  battery  as  soon  as 
fully  charged,  on  an  average,  a  total  of 
thirteen  3-cell  batteries,  it  is  claimed,  can 
be  given  a  full  charge  in  twenty-four 
hours,  allowing  for  the  average  amount 
of  residual  charge.  The  rotating  commu- 
tator principle  is  employed.  Current  from 
the  alternating-current  supply  is  brought 
to  two  terminals  at  the  back  of  the  switch- 
board. From  these  terminals  the  current 
passes  thru  the  line  switch  to  a  special  in- 
duction-type motor.  On  the  extended  shaft 
of  thre  motor  are  two  collector  rings  and 
beyond  them  a  commutator.  The  syn- 
chronous motor  is  of  such  design  that  no 
further  attention  need  be  given  in  starting 
than  to  simply  close  the  line  switch,  at 
which  time  the  motor  will  start  readily  and 
fall  into  synchronism,  remaining  so,  it  is 
said,  even  at  a  great  reduction  in  voltage. 


EFFECT  OF  ELECTRICITY  ON 
CROPS. 

Important  experiments  on  the  applica- 
tion of  electricity  to  agriculture  are  being 
made,  under  government  grant,  at  Hunt- 
ington, in  Hereford,  England.  As  is  well 
known,  high-tension  discharge  accelerates 
the  growth  of  plants,  and  may  lead  to  a 
considerable  increase  in  the  yield  of  crops 
from  a  given  area.  Associated  with  these 
experiments  are  Prof.  T.  H.  Blackman, 
Mr.  W.  Duddell  and  Mr.  I.  Jorgensen,  a 
Danish  expert.  Mr.  W.  J.  Kerr,  city  elec- 
trical engineer  of  Hereford,  is  also  con- 
cerned with  the  movement. 


October,  1917 


THE  ELECTRICAL  EXPERIMENTER 


379 


THE  RECORD-LITE  ILLUMINATES 
THE  VICTROLA  NEEDLE. 

The  miniature  electric  light  for  phono- 
graphs here  shown  is  a  neat,  ornamental 


This  condition  is  fulfilled  in  the  binocu- 
lar magnifier  illustrated  herewith  by  ar- 
ranging two  rhombohedric  prisms  so  as  to 
reduce  the  distance  between  the  two  fields 
of  view  and  thus  place  them  within  com- 
paratively small  convergent  angles. 

The  magnifying  lens  system  is  arranged 
so  that  any  desired  magnification  can  be  ob- 
tained by  inserting  the  proper  lenses.  The 
maximum  magnification  recommended  is 
three  diameters,  which  allows  of  a  large 
range  of  working  distance. 

The  eye-piece  caps  are  made  of  ebonite 
shaped  to  fit  snugly  over  the  edges  of  the 
orbit,  the  entire  instrument  being  held  in 
place  by  an  adjustable  elastic  or  special 
fiber  head-band  fitting  around  the  head. 
Apertures  are  provided  in  the  eye-pieces 
for  ventilation  and  to  prevent  moisture  col- 
lecting on  the  lens  surface. 

To  facilitate  the  examination  of  cavities 
and  dark  uneven  specimens,  etc.,  an  illumi- 
nating appliance  can  be  fitted  to  the  head- 
band. This  consists  of  a  small  incandes- 
cent lamp  operating  on  dry  cells,  as  shown. 


Have  You  bnatoied  Victrola  Records  Now 
and  Then  While  Trying  to  Adjust  the  Needle? 
The  Record-lite  Was  Designed  to  Obviate 
This  Difficulty.    It  Works  on  Batteries. 

attachment,  that  comes  complete  and  ready 
for  use.  The  installation  is  simplicity  it- 
self— the  light  is  slipt  over  the  end  of 
a  taper  tube  or  tone  arm,  until  it  snaps 
into  position  and  is  ruggedly  and  per- 
manently fastened.  The  battery  box  is  set 
in  the  left-hand  rear  corner  of  the  ma- 
chine, or  may  be  concealed  inside  the  ma- 
chine. 

The  operation  is  equally  as 
simple.  The  second  finger  of 
the  left  hand  rests  naturally  on 
the  contact  spring  when  oper- 
ating the  machine  and  the  light 
illuminates  the  record,  where  the 
needle  rests.  As  soon  as  the 
hand  is  removed,  the  light  auto- 
matically goes  out.  The  equip- 
ment includes  a  three-cell  dry 
battery,  and  a  four-volt  flash- 
light battery  lamp. 


NEW     OSCILLATING  ELECTRIC 
WASHER  A  TIME-SAVER. 

The  oscillator  principle  followed  in  de- 
signing the  new  electric  washing  machine 
here  shown  utilizes  both  suction  and  com- 
pression force  of  air  within  its  vacuum 
chamber.  When  in  use  the  dasher  oscil- 
lates in  up  and  down  motion  something 
like  a  child's  teeter-totter.  It  is  available 
in  either  electric  motor  drive  or  gasoline 
engine  drive. 

As  the  dasher  raises  out  of  the  water 
the  vacuum  chambers  fill  with  air — when 
it  goes  down  into  the  water  the  force  of 


ELECTRIC  BINOCULAR 
MAGNIFIERS. 
\  By  Thos.  W.  Benson. 

The  binocular  magnifier  has 
been  designed  to  enable  medical 

men,  zoologists,  geologists,  bot-  Electricity"  Has  Reduced  Wash-day  Labors  to  Child's 
anists,  art  metal  workers,  watch-  Play,  Thanks  to  the  Motor  Which  Not  Only  Rubs  the 
makers,  and  others  called  upon  clothes  But  Wrings  Them  as  WelL 


to  examine  small  objects  with  a 
low  magnification,  to  do  so  con- 
veniently and  with  both  eyes 
simultaneously. 

Binocular  vision  in  such  a  device  has 
always  been  desirable  in  order  to  gain 
perception  of  depth,  but  optical  means  here- 


Thls  Binocular  Magnifier  Is  Fitted 
with  a  Small  Electric  Battery  Lamp 
for  Illuminating  Dark  Cavities. 


to  fore  available  proved  insufficient  to  pro- 
vide it.  Binocular  vision  correctly  applied 
not  only  results  in  better  definition,  but 
allows  the  operator  to  observe  the  object 
in  relief,  giving  practically  a  natural  per- 
spective. 


the  air  compression  drives  the  hot  suds 
thru  the  clothes — then  on  its  upward  swing 
the  air  suction  draws  the  suds  back  thru 
the  clothes.  All  the  washing  is  therefore 
done  thru  the  use  of  air  pressure  and 
suction.  This  eliminates  all  rubbing, 
swishing  around  on  pegs 
and  other  mechanical  action 
that  wears  and  tears  clothes. 

The  machine  is  said  to 
wash  anything  that  can  be 
washed  with  soap  and  wa- 
ter, cleaner  and  quicker 
than  by  any  other  method. 
The  most  delicate  fabrics 
being  washed  without  per- 
ceptible wear.  All  gearing 
is  enclosed  for  the  protec- 
tion of  the  operator. 
Included  as  part  of  the  regular  equip- 
ment is  a  swinging  wringer — also  a  spe- 
cial folding  bench.  Also  there  is  provided 
quick  wringer  release,  safety  hand  control, 
safety  foot  control — the  complete  outfit 
wrings  and  washes  at  the  same  time. 


ELECTRICALLY  OPERATED  AND 
LIGHTED  ALARM  CLOCK. 

A  great  convenience  in  a  bedroom  is  to 
have  a  reliable  alarm  clock  to  arouse  the 
sleeper  in  ample  time  for  the  day's  duties. 


Automatic  Electric  Alarm  Clock  with  Nlte- 
lite  Attachment  for  Illuminating  Dial. 


Such  a  clock,  electrically  operated  and 
with  a  special  electric-light  attachment,  has 
now  been  made  by  a  New  York  concern. 
As  shown  in  the  illustration,  this  is  a 
handsome  clock  which  adds  to  the  appear- 
ance of  any  dresser  or  other  bedroom  fur- 
niture. The  clock  is  electrically  wound. 
In  the  bottom  of  the  clock  case  is  a  dry 
cell  which  furnishes  current  for  operating 
the  clock,  for  ringing  the  alarm  and  for 
lighting  the  lamp  shown  just  below  the 
dial.  This  lamp  is  controlled  by  a  push- 
button connected  to  a  cord  of  considerable 
length,  the  button  being  placed  near  the 
bed  so  that  by  pressing  it  the  dial  is  il- 
luminated and  the  time  observed  at  any 
period  of  the  night  without  getting  out 
of  bed  or  other  discomfort. 


A  NEW  SOLDER-LESS  WIRE 
CLAMP. 

Wire-clamp  connectors  for  circuits, 
fixtures  and  grounding  purposes  which  are 
designed  to  connect  four  wires  or  less  of 
different  sizes  without  the  use  of  heat 
are  now  being  offered.  To  connect  the 
wires  the  screws  of  the  device  are  loosened 
slightly  and  each  wire  is  inserted  in  one 
of  the  four  loops  and  securely  connected 
by  tightening  the  screws.  A  knurled  sur- 
face is  provided  on  the  nut  threaded  on 
each  screw  so  it  will  grip  the  wire  and  not 


A  Clever  Wire  Clamp  Which   Requires  No 
Solder.    Particularly  Useful  to  Electrical  Ex- 
perimenters   for    Making    Various  Circuit 
Changes  Quickly. 

turn  when  the  screw  is  drawn  up.  These 
connectors  are  also  made  for  grounding 
work.  They  are  very  useful  to  electrical 
experimenters  for  making  connections  in 
the  laboratory  and  among  instruments. 


380 


THE  ELECTRICAL  EXPERIMENTER 


October,  1917 


Are  There  Currents  About  A  Magnet  ? 

By  F.  F.  MAGE,  Superintendent  of  Public  Schools,  Dallas,  Texas 


IN  a  previous  article  in  regard  to  Mag- 
neto-graphs it  was  demonstrated  be- 
yond controversy  that  there  is  actual 
motion,  that  there  are  actual  currents, 
about  a  magnet,  even  a  permanent 
magnet,  and  that  this  motion,  these  cur- 


torsion  of  the  thread  does  not  become  too 
great.  With  a  powerful  magnet  the  rota- 
tion may  be  even  continued  to  the  breaking 
point  of  the  thread.  But  the  revolution  is 
always  counter-clock-wise  over  the  North 
pole  and  clockwise  over  the  South  pole. 

B,  C,  and  D 
may  be  made  to 
revolve  in  the  same 
manner  and  the  di- 
rection is  always 
the  same.  "E"  in 
the  same  figure  is 
a  helix  without  an 
iron  core.  The 
same  result  may  be 
obtained  with  this 
as  with  the  electro- 
magnet F. 

If  A,  B,  C,  and 
D  are  suspended  as 
before  and  a  per- 
manent bar  magnet 
is  brought  under- 
neath and  rapidly 
thrust  up  and 
down,  they  will  ro- 
tate as  before ;  that 
is,  counter  -  clock  - 
wise  over  the 
North  pole  and 
clock-wise  over  the 
South  pole. 

Here  then,  if  it 

Apparatus  Used  by  the  Author  for  Demonstrating  that  Rotary  Motion    u.j  „nt  ~\ra~A„ 
Is  Created   in   Suspended   Magnetic  Objects  When  the  Current  In  t.    naa  not  a i r e a  a  y 
Magnet  Coil  Below  Them  Is  Suitably  Interrupted.  been  proven  by  the 

effect  of  the  mag- 
rents,  are  of  sufficient  potentiality  to  affect  net  upon  a  photographic  plate,  is  proof  that 
a  photographic  plate  and  to  penetrate  wood,  there  is  motion — that  there  are  currents — 
thin  sheets  of  metal,  and  other  substances.  about  the  poles  of  a  magnet  and  that  these 
In  the  present  discussion  further  proofs  of  currents  are  the  same  about  an  electro-mag- 
these  facts  will  be  added  and 
the  direction  and  the  character 
of  these  currents  will  be  given. 
(See  May,  1917,  issue.) 

In  order  to  follow  the  sub- 
ject in  a  perfectly  logical  man- 
ner I  should  begin  with  an  ex- 
periment in  regard  to  currents 
surrounding  a  charged  wire, 
which  experiment  will  be  given 
later,  but  that  this  demonstra- 
tion may  be  at  once  striking 
and  convincing  I  shall  first  set 
out  other  experiments  the  con- 
clusions from  which  are  too 
obvious  to  be  overlooked  or 
denied. 

In  Figure  1,  at  "A"  is  shown 
a  cork  thru  which  are  thrust 
straight,  flat  pieces  of  iron  or 
steel.    "B"  is  the  same  except 
that  round  iron  wire  is  used 
in  the  place  of  the  flat  strips. 
"C"  is  an  iron  wire  bent  at 
right  angles  to  its  axis  when 
hanging.    "D"  is  an  iron  wire 
bent  at  an  obtuse  angle  to  its  axis  when 
suspended.     When    A    is    suspended  by 
a  thread  of  unspun  silk  or  a  hair  over  the 
electro-magnet  "F"  and  the  current  passing 
thru  the  coil  of  the  magnet  is  alternately 
made  and  broken  by  means  of  a  key,  A  will 
revolve  rapidly.   If  the  direction  of  the  cur- 
rent is  such  as  to  make  the  upper  pole  a 
North  pole  the  rotation  will  be  counter- 
clock-wise.    If  by  means  of  a  pole  reverser 
the  upper  pole  is  made  a  South  pole  the 
revolutions  will  be  clock-wise.    This  rota- 
tion may  be  checked  and  reversed  at  any 
point  by  reversing  the  current  so  as  to  re- 
verse the  poles :  the  only  precaution  neces- 
sary being  to  hold  the  current  for  an  instant 
at  the  point  of  reversal  so  that  the  rotation 
is  stopt.   The  revolutions  may  be  continued 
to  any  length  in  one  direction  provided  the 


Fig.  2. — Showing  the  Lines  of  Force — or  Rather  a  Map  of  the  "Cur- 
rents" About  a  Powerful  Magnet.    Taken  by  Means  of  Iron  Filings 
Sprinkled  on  a  Sheet  of  Glass  Under  Which  the  Magnet  Is  Placed. 
Then  the  Current  Thru  the  Coil  Was  Made  and  Broken. 

net  and  a  permanent  magnet.    Moreover,  it 
is  plainly  indicated  that  these  currents  not 
only  move  toward  the  magnet  but  that  they 
also  rotate  in  their  forward  progress  coun- 
ter-clock-wise over  the  North  pole  and 
clock-wise  over  the  South  pole.  A  moment's 
consideration  will  show 
that  these  currents  thus 
form    a  continuous 
spiral  about  the  magnet 
and  that  this  spiral  con- 
forms to  the  direction 
of  the  current  about  an 
electro-magnet  in  both 
the  electro-magnet  and 
in  the  permanent  mag- 
net. No  one  capable  of 
logical  thinking,  even  if 
it  had  not  already  been 


proven  that  there  are  currents  about  the 
magnet,  and  currents  capable  of  penetrat- 
ing substances  and  affecting  photographic 
plates,  will  doubt  that  here  is  motion — 
currents — and  that  these  currents  are  rotary. 
Lines  of  stress,  or  any  other  assumption 
can  not  account  for  this  motion  of  the 
objects.  Even  a  child  recognizes  the  effect 
of  currents  in  the  moving  straws  and  de- 
termines the  direction  of  the  currents  by 
the  path  of  the  straws. 

Nor  would  an  assumption  that  this  motion 
of  the  objects  is  produced  by  an  attempt 
of  the  partially  magnetized  iron  to  set  it- 
self tangent  to  the  lines  of  force  about  the 
magnet  appear  to  be  tenable.  In  Fig.  1,  A 
may  be  made  with  strips  of  soft  iron  or  it 
may  be  made  with  steel  magnets.  The 
magnets  may  be  arranged  in  pairs  with 
their  poles  in  the  same  direction,  or  they 
may  be  arranged  in  pairs  with  their  poles 
neutralizing  each  other.  In  any  arrange- 
ment the  result  is  the  same,  and  the  direc- 
tion of  rotation  is  the  same.  If  "D"  is 
used  instead  of  "A,"  the  magnet  will  tem- 
porarily impart  to  the  lower  end  of  the 
wire  a  magnetism  opposite  to  that  of  the 
pole  of  the  magnet.  The  tendency  then  is 
for  the  lower  end  of  the  wire  to  be  strongly 
attracted  to  the  magnet  and  to  point  to  the 
center  of  the  pole,  but  instead  of  this  it 
swings  in  ever-widening  circles  about  the 
pole  of  the  magnet,  the  point  of  the  wire 
becoming  further  and  further  from  the 
magnet.  Then  we  may  go  further.  A  loose 
"snarl"  of  soft  iron  wire  may  be  suspended 
in  the  place  of  the  other  objects.  The 
result  is  the  same.  Yet  it  would  take  quite 
a  stretch  of  imagination  and  a  decided  de- 
termination to  adhere  to  "it  has  been  so 
written,"  to  assume  magnetic  poles  for  a 
snarl  of  wire  or  that  there 
would  be  any  tendency  to  set 
itself  tangent  to  the  lines  of 
force.  Go  even  further.  Sus- 
pend an  iron  ring  in  the  same 
manner.  Assume  that  it  be- 
comes magnetized  or  that  it 
does  not  become  magnetized. 
If  it  becomes  magnetized  the 
poles  correspond  to  a  continua- 
tion of  the  line  made  by  the 
thread.  But  in  any  case  the 
ring  revolves  as  do  the  other 
objects. 

It    has   been   customary  to 
"map  the  lines  of  force  about  a 
magnet"  by  sprinkling  iron  fil- 
ings on  a  sheet  of  glass  or  card- 
board placed  over  a  magnet  and 
then  tapping  the  glass  or  card- 
board.  Now  it  is  a  well  known 
fact  that  powder  or  iron  filings 
may  be  made  to  arrange  them- 
selves in  lines  on  glass  or  other 
substance   by   tapping  or  by 
stroking  with  a  fiddle  bow,  etc. 
The  character  and  direction  of  these  lines 
will  be  determined  to  a  great  extent  by  the 
nature  of  the  disturbance.  The  same  is  true 
when  we  tap  the  glass  over  the  magnet  only 
that  here  we  have  a  resultant  of  forces. 
Tapping  the  glass  just  right  will  produce 


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~>> 

Fig.  4. — Various  Paths  Taken  by  an  Iron  Ball  Over  a  Plane 
Surface,  Such  as  a  Card,  Placed  Inside  a  Solenoid. 


October,  1917 


THE  ELECTRICAL  EXPERIMENTER 


381 


the  conventional  lines  about  a  magnet;  tho 
it  requires  a  great  stretch  of  imagination 
to  see  the  closed  curves  passing  from  one 
pole  to  another.  Aside  from  this,  different 
tapping,  even  when  the  magnet  is  used,  will 
produce  different  results.  A  half  score  of 
"fields  of  force"  can  be  produced  in  this 
manner.  So  easy  is  this  of  demonstration 
by  anyone  that  it  is  not  worth  while  to  re- 
produce any  of  these  fields  here.  But  Fig. 
2  shows  a  map  of  the  lines  of  force — or 
more  properly  a  map  of  the  currents — ■ 
about  a  magnet  produced  without  jarring 
or  touching  the  plate  in  any  manner.  In 
this  experiment  the  electro-magnet  "F"  in 
Fig.  1,  an  electro-magnet  thirty-eight  centi- 
meters in  length,  was  used.  This  magnet 
was  placed  under  a  sheet  of  glass  on  which 
iron  filings  were  sprinkled  and  the  lines 
shown  in  the  figure  were  produced  by  mak- 
ing and  breaking  the  current  in  the  coil 
about  the  magnet.  These  lines  begin  to 
form  as  soon  as  the  circuit  is  closed.  A 
little  examination  will  show  that  the  old 
"conventional"  lines  were  erroneous  and 
that  the  theories  and  conventions  founded 
upon  them  were  still  more  so.  Note  care- 
fully the  direction  and  continuity  of  these 
lines.  In  no  place  are  they  continuous 
from  the  North  pole  to  the  South  pole  of 
the  field.  At  A,  A,  A,  A,  the  lines  actually 
make  a  sharp  reverse  curve  and  from  curv- 
ing inward  toward  the  magnet  show  a  ten- 
dency parallel  to  the  magnet  and  more  in 
the  direction  of  the  poles.  At  B,  B,  B,  B, 
the  lines  are  only  slightly  curved.    At  C, 

C,  C,  C,  no  curve  can  be  detected.  At 

D,  D,  D,  D,  there  can  be  no  question  in 
regard  to  their  being  straight  lines  and  that 
under  no  circumstances  would  they  meet 
the  lines  from  the  other  pole.  Even  at  the 
center  of  the  field,  these  lines  do  not  form 
absolutely  closed  curves.  At  E,  E,  they 
show  a  tendency  to  meet  each  other,  the 
lines  from  the  opposite  poles,  at  an  angle. 
With  some  lines  the  angle  is  quite  apparent. 
Here,  then,  is  proof  that  the  lines  of  force 
— currents — do  not  move  in  closed  curves 
from  the  North  pole  to  the  South  pole. 
That  these  are  currents  and  not  lines  of 
tension  will  be  further  emphasized  by  the 
next  experiment. 

Place  the  electro-magnet  under  a  tank  of 
water  (I  used  a  glass  bottomed  tank  placed 
over  a  magnetic  field  already  produced  by 
the  magnet)  and  in  the  water  place  a  small 
piece  of  iron  attached  to  a  cork.  When 
the  cork  is  placed  over  a  point  on  the  line 

E,  E,  and  the  circuit  of  the  magnet  is 
closed,  the  cork  will  remain  almost  if  not 
quite  stationary,  or  will  even  exhibit  a 
slight  tendency  to  drift  away  from  the  mag- 
net. If  placed  a  few  millimeters  to  the 
right  or  left  of  this  line,  it  at  once  moves 
in  the  direction  of  the  nearest  magnetic 


pole  following  closely  the  direction  of  the 
line  over  which  it  is  placed.  Note  care- 
fully that  the  cork  follows  the  curves  shown 
in  Fig.  2.  If  a  magnetic  needle  is  sub- 
stituted for  the  iron  the  action  is  the  same 
except  that  the  needle  is  attracted  or  re- 
pelled along  the  lines  according  to  its  pola- 
rity. A  magnetic  needle  placed  over  one 
pole  so  as  to  be  repelled  will  often  move  to 
the  center  of  the  field  and  there  stop.  If  a 
large  bar  magnet  is  substituted  for  the 
electro-magnet  underneath  the  water  the 
result  is  the  same.  Here,  then,  is  proof  of 
two  facts :  first,  that  there  is  actually  motion 
about  the  magnet,  currents,  and  that  these 
currents  do  not  move  from  one  pole  to 
another  but  that  the  currents  originate  near 
the  center  of  the  field  (that  is,  those  not 
entering  from  the  directions  of  the  ends  of 
the  poles)  and  move  toward  both  poles. 
Also  that  in  the  center  of  the  field  between 
the  two  poles  of  the  magnet  is  a  point  of 
neutrality  or  of  actual  repulsion,  a  point 
where  the  currents  are  outward. 

If  further  proof  is  needed  that  there  is 
an  outward  flow  of  currents  from  the 
center  of  the  magnet  it  is  furnished  by 
the  photographic  plate.  Fig.  3,  is  such  a 
plate,  taken  underneath  the  "U"  bend  of  a 
U-shaped  magnet.  "A"  shows  the  position 
of  the  plate,  the  objects,  and  the  magnet. 
"B"  shows  the  result,  the  plate  being  taken 
under  the  same  conditions  as  those  de- 
scribed for  the  other  Magneto-graphs  (See 
first  paper  in  May  issue.)  Now  a  current 
flowing  upward  would  affect  the  photo- 
graphic plate  but  would  not  produce  an 
image  of  the  objects,  for  the  reason  that 
it  would  be  flowing  toward  them  and  would 
pass  thru  the  plate  before  reaching  them. 
In  order  to  penetrate  the  objects  and  thus 


and  to  one  side.  Place  a  piece  of  iron  at 
both  ends  and  when  the  circuit  is  closed 


Fig.  6. — Map  of  the  Interior  Lines  or  "Cu 
as  Plotted  by  the  Auth 


Fig.   5. — Apparatus   for    Measuring  the 
Strength    of    the    "Interior    Current"    of  a 
Solenoid. 


make  their  impression 
on  the  plate  it  must  be 
passing  downward; 
that  is,  must  be  flowing 
outward  from  the  bend 
of  the  U  magnet.  The 
plate  speaks  for  itself. 

So  far  only  the  ex- 
terior currents  of  a 
magnet  have  been  ex- 
amined. The  interior 
currents  show  equally 
interesting  results. 
Place  the  solenoid 
"E"  in  Fig.  1,  on  its 
side  and  place  a  plane 
of  cardboard  inside  on 
a  line  with  the  diam- 
eter. Place  a  small 
piece  of  iron  on  the 
end  of  the  cardboard 
plane  and  as  soon  as 
the  circuit  is  closed 
the  iron  will  spring  to 
the  center  of  the  coil 


Demonstrating  that  There  Is  an  Outward 
Flow  of  Currents  from  the  Center  of  a  Mag- 
net. To  Make  a  "Magnetograph"  Several 
Objects  Are  Placed  on  a  Photograph  Plate 
Beneath  the  "U"-Bend,  and  Left  in  the 
Dark  for  Several  Weeks. 


Fig.  3-B. 


-"Magnetograph"  Obtained  by 
Above  Arrangement. 


rrents"  of  a  Solenoid 
or. 


they  will  meet  in  the  center  of  the  coil,  but 
it  should  be  noted  that  one  alone  will  move 
to  the  center.  This  shows  that  there  are 
currents  moving  inside  of  the  solenoid  and 
that  the  attraction  of  the  solenoid  is  not 
at  the  poles  but  at  the  center  and  toward 
the  sides.  This  is  also  proven  by  the  photo- 
graphic plate  for  photographic  plates  ex- 
posed inside  a  helix  bearing  a  current  give 
results  similar  to  the  magneto-graphs  al- 
ready shown. 

Again,  place  inside  the  solenoid  "E"  the 
cardboard  plane  as  before  and  cover  it  with 
a  soft  but  not  rough  paper.  If  an  iron 
ball  is  placed  on  the  cardboard  at  "A", 
Fig.  4,  and  the  circuit  is  closed  the  ball 
is  drawn  inward  and  to  one  side.  If  the 
same  is  repeated  by  placing  balls  in  suc- 
cession at  "B",  "C",  "D"  and  "E",  and  at 
'A1,''  "B\"  "C\"  "D1"  and  "E1"  the  result 
is  the  same.  The  balls  must  be  placed  on 
the  card  one  at  a  time  and  the  circuit 
closed  and  opened  again  before  another  is 
put  on.  If  several  balls  are  placed  on  the 
card  at  the  same  time  and  the  circuit  closed, 
their  tendency  is  to  cluster  together.  If 
these  balls  are  coated  with  oil  and  lamp 
black  they  will  leave  a  faint  trace  of  their 
several  paths.  Fig.  4  is  the  reproduction 
of  an  actual  tracing  made  on  cardboard  in 
this  manner. 

The  existence  and  strength  of  these  cur- 
rents is  emphasized  by  another  experiment. 
The  solenoid  here  shown  is  twenty  centi- 
meters in  length.  Fig.  5  shows  apparatus 
for  measuring  the  strength  of  the  interior 
current  of  this  solenoid.  "A"  is  a  small 
piece  of  iron  of  known  weight  which  is 
fastened  to  the  wooden  arm  "B".  "B"  is 
pivoted  to  the  crossbar  arm  "C",  at  "D", 
and  so  arranged  by  means  of  a  set  screw 
as  to  be  lowered  or  raised  inside  the  sole- 
(Continued  on  page  417) 


382 


THE  ELECTRICAL  EXPERIMENTER 


October,  1917 


New  Portable  Electric  Lamp  For  Miners 

By  F.  T.  FORSTER 
Pittsfield  Works,  General  Electric  Company 


WITH  the  advent  of  coal  mining  it  was 
discovered  that  open  flames  in  mines 
were  sometimes  dangerous,  owing  to 
the  fact  that  explosive  mixtures  of  methane 
gas  frequently  occurred.  This  led  to  a  series 
of  investigations  to  pro- 
duce a  lamp  that  would 
primarily  prevent  explo- 
sions and  secondly  de- 
tect the  dangerous  gas. 

The  electric  incandes- 
cent lamp  naturally 
obviates  the  objections 
found  in  the  open-flame 
type  miner's  lamp.  While 
the  electric  lamp  will  not 
detect  gas,  this  can  easily 
be  accomplished  by  em- 
ploying a  few  Davy 
lamps  for  this  purpose. 
Special  electric  gas  de- 
tectors are  now  being 
developed  and  it  will 
probably  only  be  a  matter 
of  a  few  months  before 
thoroly  reliable  devices 
of  this  type  will  be  on  the 
market. 

A  glowing  lamp  fila- 
ment has  been  proved  by 
the  Bureau  of  Mines  to 
be  dangerous.  It  is  there- 
fore necessary  to  supply 
each  device  with  a  safety 
switch  that  will  break,  or 
otherwise  discontinue,  the 
current  thru  the  filament 
when  the  bulb  is  broken. 

Tests   with   light  and 
heavy  blows  in  the  direc- 
tions most  likely  to  cause 
failure  are  applied  to 
E^ctVfc  Limpffoyr  each  device  and  it  must 
Miners.  not  fail  on  any  test  in 

order  to  pass,  for  obvi- 
ously one  failure  in  a  mine  might  mean 
death  to  many  miners  and  much  damage  to 
property. 

Batteries  must  be  proved  by  test  to  pos- 
sess a  capacity  sufficient  to  burn  the  lamp 
through  an  entire  shift  of  8  to  10  hours 
with  a  margin  of  safety. 

The  first  requisite  of  a  mine  lamp  is  to 
give  light  for  the  miner  to  find  his  way 
thru  the  various  unlighted  passageways 
to  his  work  and  then  to  enable  him  to 
perform  that  work  in  an  efficient  manner 
during  the  entire  shift.  It  is  therefore 
quite  necessary  that  the  light  should 
decrease  as  little  as  possible  in  brillian- 
cy during  the  time  the  miner  is  "in- 
side." This  is  accomplished  by  using 
an  ironclad  storage  battery  whose 
voltage  characteristic  is  very  even. 
Except  for  the  sudden  small  decrease 
in  voltage  which  takes  place  in  the 
first  few  minutes  on  a  freshly  charged 
battery,  the  change  over  9  hours  is 
only  6  per  cent,  or  less  than  1  per 
cent  per  hour. 

The  distribution  of  light  is  excep- 
tionally good.  A  porcelain  reflector 
of  irregular  shape  is  used,  thereby 
eliminating  those  sharp  changes  in 
brilliancy  that  are  characteristic  of 
polished  metal  reflectors. 

The  cap  shell  is  fitted  with  hooks 
for  mounting  the  lamp  on  the 
miner's  cap  at  such  an  inclination 
forward  as  to  throw  the  beam  of 
light  directly  upon  the  work  which  the 
miner  is  doing. 

In  this  type  of  miners'  lamp,  the  safety 
feature  consists  of  two  flexible  contacts 
which  hold  an  elliptical-shaped  bulb  hav- 


ing a  contact  at  either  end  with  the  fila- 
ment extending  thru  the  lamp  between  its 
two  contacts.  The  illustration  shows  this 
safety  device  lamp  mounting  for  holding 
the  bulb.  Any  blow  which  will  break  the 
bulb  in  any  manner  will  force  the  lamp 
out  of  the  contacts. 

Much  depends  upon  the  battery,  of 
course.  If  it  does  not  supply  current  to 
light  the  lamp  for  the  full  working  time 
the  miner  will  have  to  stop  work  sooner 
than  otherwise,  thus  decreasing  the  output 
of  coal  for  the  mine  owner  and  causing 
a  loss  of  pay  to  the  miner.  It  may  also 
be  difficult  for  him  to  find  his  way  out  of 
the  mine  if  he  does  not  have  assistance 
from  someone  who  has  a  lamp.  With  the 
ironclad  battery,  a  reliable  source  of  power 
is  assured.  The  lead  battery  plates  are 
very  rugged  and  have  established  a  repu- 
tation in  mine  locomotives  and  heavy  trucks 
for  their  ability  to  withstand  heavy  duty 
conditions  and  severe  shaking.  The  plates 
are  contained  in  a  strong,  well-designed, 
semi-hard  rubber  jar  that  will  stand  an 
unusual  amount  of  abuse.  By  making  the 
metal  containing  case  of  proper  design  for 
the  conditions  under  which  the  equipments 
are  to  operate,  no  trouble  has  been  experi- 
enced from  cracked  or  broken  jars.  The 
cover  is  fastened  to  the  jar  by  a  double 
capillary  seal,  which  is  acid-tight. 

The  filling  and  venting  scheme  is  very 
simple  and  effective.  To  fill  the  battery  the 
vent  plug  is  removed,  which  gives  free 
access  to  the  cell  space,  and  the  level  of 
the  electrolyte  is  brought  to  within  a  small 
distance  below  the  edge  of  the  plug  open- 
ing. The  vent  plug  is  very  effective  in 
preventing  spilling  of  the  electrolyte  and 
is  securely  sealed  in  place  by  a  quarter- 
turn  of  the  plug,  which  draws  it  down 
against  a  rubber  basket  in  a  suitable  seated 
surface  on  the  jar  to  prevent  any  leakage 
of  acid.  The  electrolyte,  which  is  the  usual 
battery  acid  (sulfuric),  is  corrosive  in  its 
action  on  metals  and  will  damage  all  kinds 
of  cloth  except  pure  wool,  yet  on  account 
of  the  degree  of  perfection  which  has 
been  obtained  in  making  a  strong  non- 
breakable  jar,  a  perfectly  seated  vent  plug, 
and  a  non-spilling  vent  no  acid  can  escape. 


SECRET  WIRELESS  RAZED. 

Costa  Rican  Government  authorities  have 
dismantled  a  powerful  wireless  station  at 
Heredia  that  is  supposed  to  have  been  used 
by  Germans.    It  was  found  on  the  property 


New  Electric  Miner's  Lamp  Disassembled. 

of  the  former  Governor  of  Heredia  Prov- 
ince, Dr.  Marcos  Rodriguez,  an  intimate 
friend  of  the  deposed  President,  Alfredo 
Gonzales,  and  of  the  latter's  adviser,  J. 
Kumpel. 


ELECTRIC    CLOCK    DRIVEN  BY 
EARTH  CURRENTS. 

This  clock,  unlike  an  ordinary  time- 
piece, is  not  actuated  by  either  weights  or 
springs.  The  motive  force  is  a  current  of 
electricity  obtained  from  a  pair  of  plates 
buried  in  old  Mother  Earth,  and  which 
are  connected  with  the  clock  by  wires. 

The  current 
is  applied  by 
means  of  an 
electro  -  magnet 
direct  to  the 
pendulum,  s  o 
that  the  pendu- 
lum drives  the 
clock,  instead  of 
the  clock  driv- 
ing the  pendu- 
lum, as  is  the 
case  where 
weights  or 
springs  are 
used. 

The  current 
is  reversed  at 
each  swing  of 
the  pendulum 
by  an  automatic 
switch,  and  this 
switch  is  so  ad- 
justed  as  to 
prevent  the  pen- 
dulum being 
moved  in  either 
direction  b  e  - 
yond  a  given 
point.  It  is  the 
application  o  f 
this  principle 
which  secures 
correct  time  and 
overcomes  any 
slight  variation 
in  the  strength 
of  current,  and 
it  is  this  which 
makes  the 
Earth  -  Driven 
Clock  a  distinct 
advance  upon 
electric  clocks 
a  s  previously 
made. 

An  interesting 
report  has  been 
given  on  this 
clock  by  Profes- 
sor Silvanus  P. 
Thompson,  F.R.S.,  the  world-renowned 
electrical  expert,  who  has  minutely  exam- 
ined the  clock.  The  following  are  extracts 
from  his  report : — 

"Having  had  the  opportunity — both 
to  see  the  earth-driven  clock  at  work, 
and  to  examine  the  specifications  of 
patent  on  this  invention,  I  beg  to  re- 
port as  follows : 

"The  pendulum  is  both  the  govern- 
ing part  and  the  driving  part  of  the 
clock.  I  made  various  simple  tests 
on  the  clock  with  a  milli-ampere  meter 
attached  to  the  circuit.  If  I  pur- 
posely gave  the  pendulum,  by  hand,  a 
large  impulse  so  that  it  swung  too 
far,  at  once  the  automatic  action  of 
the  contact  device  became  evident, 
and  after  a  few  swings  the  current 
returned  to  its  normal  value,  and  the 
pendulum  to  its  normal  swing. 

"It  is,  as  will  appear  from  the 
above  description,  entirely  automatic 
and  self-contained. 

"I  see  no  reason  to  doubt  that  with 
an  earth  battery  properly  laid,  it  will 
continue  to  go  for  years  without  stopping. 

"I  have  used  earth  batteries  many  years 
ago,  and  know  them  to  be  extremely  con- 
stant if  they  are  properly  laid  down  in  the 
earth  once  for  all." 


The  Electric  Clock  We 
Have  All  Dreamed  of. 
It  operates  on  Electric 
Current  from  the  Earth. 
No  Battery  Required. 


October,  1917 


THE  ELECTRICAL  EXPERIMENTER 


383 


MILK  SHAKES  BY  MOTOR  IN  10 
SECONDS. 

Several  new  and  excellent  features  are 
embodied  in  the  new  motor-driven  mixer 


The  Day  of  the  Hand-Made  Milk  Shake  Is 
Past,  Thanks  to  the  Always- Ready  Electric 
Motor. 


here  illustrated.  The  entire  base  and 
column  is  finished  in  white  porcelain 
enamel.  It  can  be  easily  kept  clean  and 
dispensers  will  appreciate  this  sanitary 
feature. 

The  motor  which  drives  the  mixing 
spindle  is  stationary  on  the  head  of 
the  column,  only  the  mixing  spindle 
moving  up  and  down.  The  spindle  is 
light  and  the  mixer  is  very  easily  oper- 
ated. The  current  is  automatically 
turned  on  when  the  spindle  engages 
with  the  driving  disk  on  the  motor  and 
is  shut  off  instantly  when  the  spindle 
is  raised.  This  does  away  with  the 
splashing  of  the  contents  outside  of  the 
container  as  is  experienced  with  other 
types  of  mixers. 

Another  advantage  of  this  mixer  is 
that  the  spindle  raises  to  a  height  of 
7^2  inches,  enabling  the  largest  con- 
tainer or  mixing  glass  to  be  set  under 
the  spindle  without  tipping  the  con- 
tainer. 


is  drawn  into  a  section  of  the  base.  The 
air  created  by  the  strong  suction  is  filtered 
before  it  comes  out  of  the  exhaust.  This 
is  one  way  of  solving  the  black-board  and 
chalk  problem,  but  it's  a  wonder  to  us 


ELECTRICITY  CLEANS  ERAS- 
ERS RIGHT  IN  SCHOOL- 
ROOM. 

With  the  machine  here  shown  eras- 
ers are  cleaned  right  in  the  school- 
room or  in  the  corridor.  No  need  to 
throw  them  into  a  basket  and  take 
them  outside  or  into  the  basement.  A 
small  girl  can  operate  the  device  and 
get  the  erasers  thoroly  clean. 

Turning  the  switch  sets  a  rapidly  re- 
volving brush  in  motion.   This  loosens 
the  dust  and  the  suction  developed  by  the 
motor  extracts  all  of  the  dust  from  the 
surface  and  crevices  of  the  felt.    The  dust 


Electricity    Now   Cleans   the    Germ-Laden  Black- 
Board  Eraser  In  a  Thoro  and  Sanitary  Manner. 


that  some  genius  has  not  perfected  a  more 
cleanly  and  scientific  school-room  appurte- 
nance than  the  "black-board  eraser." 


The  Effect  of  Ultra 


THE  actions  presented  by  the  ultra 
violet  rays  on  animal  substances,  or 
to  state  better,  the  changes  produced 
on  infinitesimal  life  by  the  ultra 
violet  rays,  are  such  as  to  leave 
much  doubt  and  supposition  as  to  their 
qualities  as  a  friend  of  man.  Still  their 
chemical,  physical  and  biological  actions 
are  not  as  yet  known  well  enough  that  we 
might  say  a  priori  that  they  are  detrimental 
or  beneficial.  The  transformations  pro- 
duced by  these  rays  are  evident  and  show 
their  existence,  but  just  how  this  action 
forms  or  develops  is  yet  to  be  explained, 
and  it  would  be  hazardous  "to  state  a  fact 
on  a  subject  which  can  be  clast  only  in 
the  same  category  with  the  undiscovered 
merits  of  the  X-Ray. 

In  1912,  Holland  had  averred  that  the 
ultra  violet  rays  were  an  enormous  microbi- 
cide  on  animal  substances,  and  they  imme- 
diately adopted  the  ultra  violet  rays  to 
sterilize  their  milk  by  passing  it  from  one 
container  to  another  in  a  thin  film  or 
stream  upon  which  was  projected  the  ultra 
violet  ray.  This  was  supposed  to  have  the 
action  of  sterilization  and  preservation. 
The  fact  of  sterilization  existed,  but  while 
certain  microbes  were  destroyed  in  this 
manner,  especially  those  which  are  injuri- 
ous to  human  life,  it  did  not  prevent  the 
milk  from  turning  sour ;  on  the  contrary 
the  development  of  the  germs  under  the 
action  of  the  ultra  violet  rays  was  so  great, 
that  they  seemed  to  find  themselves  in  a 
most  favorable  environment,  which  was 
clearly  seen  under  microscopic  inspection. 
In  fact,  upon  projecting  an  ultra  violet  ray 
on  a  vessel  containing  milk,  it  would  be 
seen  that  the  section  upon  which  this  ray 
touched  becomes  a  veritable  tumultuous 
life  of  multiplication  of  germs.  This 
clearly  indicated  that  while  the  microbicide 


Violet  Rays  on  Mil 

By  DR.  HUMBERT  BIZZONI 

idea  of  the  ultra  violet  rays  exists,  its 
application  is  on  a  different  principle. 

It  has  always  been  commonly  believed 
that  milk  curdles  owing  to  the  change  of 
temperature  and  that  by  using  ice  this  dif- 
ficulty would  be  overcome,  but  this  pre- 
caution does  not  take  away  the  primal  cause 
which,  while  it  remains  latent  under  the 
unfavorable  environment  of  perhaps  zero 
degree,  develops  immediately  upon  being 
brought  in  contact  with  light  and  a  more 
productive  environment,  namely,  the  mo- 
ment that  the  ultra  violet  rays  come  in 
contact  with  the  infinitesimal  life  their  de- 
velopment begins,  and  while  it  is  true  that 
some  microbes  are  destroyed  by  the  ultra 
violet  rays,  it  has  been  found  that  the 
inferior  organisms  generally  develop  more 
rapidly  under  the  influence  of  these  rays. 

The  milk  of  the  Bulgarians,  well  known 
all  over  the  world  for  its  superior  nutri- 
tive quality,  is  made  by  exposing  it  to  the 
sun,  the  rapid  development  of  the  germs 
under  the  action  of  the  ultra  violet  rays 
being  such  that  when  it  becomes  dry  they 
are  in  highly  concentrated  form. 

The  difficulty  of  transporting  milk  from 
one  city  to  another  is  well  known,  and  I 
had  occasion  of  demonstrating  my  beliefs 
on  the  action  of  the  ultra  violet  rays  by 
an  experiment  at  which  were  present  the 
representative  commissioners  of  milk  of 
Mulhausen,  Alsace.  It  was  midsummer 
(July)  and  we  took  milk  directly  from  the 
cow,  without  it  having  had  any  exposure 
to  the  light,  and  placed  it  in  two  cans,  one 
of  which  had  been  previously  protected 
against  the  sun's  ultra  violet  rays ;  the 
other  canteen  was  left  as  it  had  been. 
The  canteens  were  then  placed  on  an  un- 
covered freight  car  without  any  ice  or  other 
protection  against  the  sun  and  shipt  to 
Colmar,  a  trip  of  about  four  hours.  Upon 


and  Other  Aspects 


arriving  at  our  destination  the  cans  were 
then  examined ;  the  milk  in  the  can  not 
protected  had  already  turned  sour,  while 
the  milk  in  the  other  can  was  as  sweet  and 
fresh  as  tho  it  had  been  hardly  drawn. 
The  fact  that  the  ultra  violet  rays  could 
not  penetrate  the  protective  covering  of 
the  canteen  prevented  any  action  on  the 
milk. 

To  substantiate  my  theory,  Dr.  Stahel  of 
the  Internationale  Cellulose  Ester  Gesell- 
schaft  of  Sydowsaue  had  also  asked  for  a 
patent  of  a  product  which  was  precisely 
against  the  action  of  the  ultra  violet  rays, 
preventing  the  decomposition  of  diverse 
animal  substances  influenced  by  these  rays, 
following  several  discoveries  made  from 
various  observations  of  the  action  of  the 
ultra  violet  rays. 

The  cerebral  substances  are  decomposed 
by  the  ultra  violet  rays,  causing  sunstroke, 
and  not  by  heat  as  generally  believed,  and 
to  substantiate  this  statement  it  is  not 
thought  remarkable  that  we  never  hear  of 
cases  of  so-called  heat  prostration  among 
the  workers  in  foundries,  glass  and  pottery 
factories,  etc.,  where  an  excessive  heat 
temperature  equal  to  mid-summer  in  the 
torrid  zone  is  continually  preserved,  and 
where  the  man  goes  back  and  forth  to  and 
from  his  labor  year  after  year  unaffected. 
Yet  this  same  man  may  be  taken  with  a 
sunstroke  in  a  moment's  time  upon  ex- 
posure to  the  sun,  when  its  rays  are  suffi- 
ciently powerful  to  react  on  the  body. 

In  1913  I  had  submitted  an  experiment 
for  the  protection  of  men  and  horses 
against  the  effects  of  the  ultra  violet  rays 
by  the  application  of  a  protective  coating 
against  these  rays  placed  in  the  inside  of 
hats  and  horse  bonnets.  Upon  the  success 
of  the  same  the  French  Government  used 
(Continued  on  page  421) 


384 


THE  ELECTRICAL  EXPERIMENTER 


October,  1917 


A     NEW     PORTABLE  ELECTRIC 
FIRE  DETECTOR. 

The  new  electric  fire  detector  is  a  ther- 
mometer constructed  of  a  steel  tube  for  a 
mercury  receptacle,  to  which  is  attached  the 
lower  contact  screw,  also  the  regulating 
screw  by  which  the  detector  is  set  to  any 
given  degree  from  zero  up  to  as  high  as 


An  Electric  Fire  Detector  Which  Can  Be 
Left  at  Any  Point  Desired,  Such  as  in  the 
Kitchen,  and  as  Soon  as  Blaze  Occurs  the 
Alarm  Bell  Rings.  It  Utilizes  a  Fine  Mer- 
cury Column,  Which  Expands  When  Heated, 
Thus  Closing  the  Bell  Circuit.  It  Will  Also 
Announce  a  Drop  in  Temperature. 

conditions  require.  A  fiber  tube  carries 
the  upper  contact  screw.  This  fire  detec- 
tor and  alarm  may  be  termed  almost  "su- 
per-human," never  failing  to  give  an  alarm 
of  fire  when  in  its  incipiency  and  which 
can  be  extinguished  with  a  pail  of  water 
or  small  portable  fire  extinguisher  and  be- 
fore it  has  gotten  beyond  individual  con- 
trol. The  detector  will  not  give  a  false 
alarm  when  properly  set,  it  is  claimed. 
The  portable  outfit  shown  is  for  use  in 
kitchens  or  other  localities. 

The  possibilities  of  this  detector  are  un- 
limited, giving  a  positive  alarm  of  fire  at 
the  opportune  time ;  the  absolute  automa- 
tic control  and  closing  of  fire-doors  and 
shutters ;  the  announcement  of  rising  tem- 
peratures in  refrigeration  plants  and  the 
absolute  control  of  open-head  sprinkler  sys- 
tems. 

As  a  valuable  equipment  for  the  pre- 
vention of  disastrous  fires,  the  detector 
gives  an  alarm  long  before  the  automatic 
sprinkler  will  operate ;  thus  not  only  pre- 
venting fire  loss,  but  eliminating  the  water 
damage  to  a  very  large  degree.  For  ware- 
houses and  holds  of  ships  where  cotton  is 
stored,  an  alarm  is  given  when  the  cot- 
ton first  begins  to  smoulder.  This  also  ap- 
plies to  uncured  hay  and  rubbish. 

The  apparatus  is  peculiarly  adapted  for 
the  regulation  of  temperature  in  refriger- 
ation plants,  being  regulated  to  announce 
the  rise  in  temperatures  on  an  annunciator 
in  the  chief  engineer's  office,  which  obviates 
the  necessity  of  continually  making  the 
rounds  to  read  the  thermometers. 

The  detectors  can  be  set  to  show  a  rise 
of  a  fraction  of  a  degree  and  a  warning 
of  this  change  given  as  above  described. 
The  detectors  for  protection  in  hotels, 
theaters,  homes,  apartment  houses,  office 
buildings  and  buildings  of  like  character  are 
.set  to  operate  at  say  110°  and  are  furnished 


with  ornamental  guard  of  nickel-plated  non- 
corrosive  metal,  which  makes  a  neat,  at- 
tractive outfit,  but  these  can  be  more  elabo- 
rately decorated  to  architect's  specifica- 
tions. 

Each  detector  will  under  ordinary  con- 
ditions cover  an  area  of  250  square  feet  of 
floor  space.  In  a  room  say  12  by  15  feet, 
one  detector  would  be  sufficient,  but  if  fas- 
tened to  side  walls,  two  would  be  required. 


chief  electrician.  Board,  lodging  and  cloth- 
ing allowances  are  given  in  addition  to  the 
regular  salary. 


RADIO    EXPERTS    NEEDED  FOR 
NEW  MERCHANT  MARINE 

There  is  a  very  great  need  in  the  navy 
just  now  for  radio  operators,  according  to 
the  Buffalo  office  of  the  Naval  Reserve. 
These  operators  are  to  be  used  on  the  giant 
merchant  marine  that  is  shortly  to  be  put 
in  service.  The  men  in  this  service  are 
well  paid.  There  are  several  classes  in  this 
service  so  that  the  beginner  has  a  chance 
for  enlistment. 

H 


DON'T  MISS  THE  NOVEMBER 

"E.E." 

We  have  a  great  variety  of  electri- 
cal, scientific  and  radio  articles  in 
preparation  for  the  "November" 
number.  You  can  rest  assured  that 
you  will  find  a  big  15  cents  worth  of 
reading  matter  in  that  issue.  If  you 
are  interested  in  war-time  inventions 
in  this  field,  you  must  not  miss  read- 
ing- the  up-to-date  and  authoritative 
articles  on  these  topics,  a  host  of 
which  we  publish  every  month.  Here 
are  a  few  of  the  "November"  feat- 
ures : 

"The  Use  of  the  Telephone  and 
Telegraph  in  Battle." 

"Action  at  a  Distance  as  Exhibited 
in  Selenium  Crystals ,"  by  Prof.  F.  C. 
Brown,  Ph.  D. 

"The  Marvels  of  Radio-activity," 
Part  III ,  by  Jerome  S.  Marcus,  B.  Sc. 

"Forcing  the  Growth  of  Plants  with 
High-frequency  Currents. 

"Historic  Electrical  Apparatus,"  by 
H.  IVinfield  Secor. 

A  new  electrical  story,  by  C.  M. 
Adams. 

"A  New,  Military  Application  of 
Electricity,"  by  H.  Gernsback. 

"Are  There  Electric  Currents  About 
a  Magnet?"  Part  III,  by  F.  F.  Mace. 

"Science  and  the  War" — In  the 
"Movies,"  They  Do  It. 

"Experimental  Physics — Lesson  9," 
by  John  J.  Furia,  A.B.,  M.A. 

"Chemical  Action  of  Storage  Bat- 
teries," Part  II,  by  Albert  W.  Wils- 
don. 

"Hoiv  to  Make  an  Electrically 
Played  Mandolin,"  by  McClure  Al- 
bright. 

The  Construction  of  a  Wheatstone 
Bridge,"  by  Thomas  W .  Benson. 


Class  A  is  for  amateur  operators  who 
can  send  and  receive  the  Continental  code 
at  least  ten  words  a  minute  and  can  write 
legibly.  Class  B  is  for  first-grade  com- 
mercial or  amateur  operators,  receiving  and 
sending  twenty  words  a  minute.  Third- 
class  electricians  rating  are  in  this  class. 
Class  C  men  must  have  commercial  licenses 
and  must  have  served  at  least  one  year  as 
operator  aboard  ship  and  must  send  and  re- 
ceive at  least  twenty-seven  words  a  minute 
in  Morse  and  Continental.  They  get  rat- 
ings of  electricians,  second  class.  Class  E 
is  for  men  who  have  worked  on  ocean- 
going boats  as  operators  for  at  least  four 
years  and  who  can  repair  any  break  of  ap- 
paratus. The  rating  is  that  of  chief  elec- 
trician. The  pay  ranges  from  $33  a  month 
for  third-class  men  to  $65  a  month  for 


GETS  30,000  VOLTS;  LIVES. 

Altho  30,000  volts  of  electricity  past  thru 
the  body  of  Neil  Hansen  of  Trenton,  N.  J., 
recently,  he  will  live. 

Hansen  was  cleaning  a  generator  in  the 
distributing  station  of  the  Public  Service 
Corporation  when  he  received  the  full  force 
of  the  current.  His  left  thumb  was  burned 
off,  his  hands  and  arms  were  burned  and 
the  top  of  his  head  was  blistered. 

For  a  time  he  lay  as  tho  dead.  After  he 
was  revived  he  could  not  remember  his 
name. 


PUSH-BUTTON  DYNAMO  RE- 
PLACES BATTERIES. 

Something  new  in  push  buttons  has  been 
invented  at  last  by  an  eastern  man  that  bids 
fair  to  send  the  old  dry  batteries  now  in 
use  to  ring  your  front  door  bell,  to  the  ash 
can.  It  is  quite  a  simple  arrangement,  and 
it  is  strange  that  no  one  should  have 
thought  of  such  a  simple  device.  The  but- 
ton itself  is  connected  to  a  rod  that  is 
geared  to  a  small  dynamo,  and  when  the 
button  is  pushed  the  dynamo  armature  ro- 
tates in  the  field  of  a  permanent  magnet, 
thereby  generating  enough  electricity  to 
ring  the  bell.  The  whole  unit  hardly  takes 
up  more  space  than  the  ordinary  push  but- 
ton, and  does  away  with  the  constant  ex- 
pense of  renewing  batteries.  By  referring 
to  the  photos  a  good  conception  of  the 
principle  involved  and  also  the  mechanism 
can  be  obtained. 


Well!  Well!  It  Does 
Seem  That  Our  Bat- 
tery Bill  Will  Shrink 
Now.  Bless  Us,  If 
Here  Isn't  a  "Work- 
ing Model"  of  the 
Latest  Non- Battery, 
Automatic,  Self-Gen- 
erating Door  Bell 
Outfit.  Push  the 
Button — the  Dynamo 
Spins  —  the  Bell 
Rings.  Selah! 


Here's  the  Secret  of  the  Battery-"less"  Bell 
Ringer.     By   Means  of  a  Special    Nut  and 
Worm,  the  Dynamo  Spins  Merrily  at  Every 
Push  of  the  Button. 


October,  1917 


THE   ELECTRICAL  EXPERIMENTER 


385 


Some  Electrical  Properties  of  Silver  Sulfide 


NATIVE  silver  sulfide  is  seldom  pure 
but  the  sulfide  may  be  prepared 
chemically  in  the  form  of  a  black 
powder  which  has  a  melting  point  of  about 
825°C.  It  was  found  that  the  sulfide  so 
melted  could  be  rolled  into  thin  strips  or 
drawn  into  short  wires  like  a  metal.    At  a 


Fig.  1.  Outcropping  of  Silver  in  Middle  of 
Sulfide  Strip.  The  Direction  of  the  Electric 
Current  Was  Approximately  Parallel  to  the 
Direction  of  the  Lines  of  the  Silver.  This 
Picture  Suggests  the  Possibilities  of  the 
Formation  of  Native  Silver  in  the  Earth. 

temperature  of  about  200°C.  it  becomes 
very  malleable  and  may  be  hammered  out 
on  a  hot  plate  or  drawn  thru  a  heated  draw 
plate.  Working  the  sulfide  at  this  tem- 
perature changes  its  electrical  properties. 
In  the  form  of  a  strip  which  has  been  rolled 
cold  this  substance  is  both  a  metallic  and 
electrolytic  conductor  at  the  same  time. 

*  Summary  of  a  forthcoming  Scientific  Paper  of 
the  National  Bureau  of  Standards. 


By  GEORGE  W.  VINAL 

When  drawn  hot  it  acts  like  a  metallic  con- 
ductor with  nearly  zero  temperature  co- 
efficient. 

In  making  experiments  with  the  sulfide  it 
was  necessary  to  find  some  means  of  mak- 
ing good  electrical  contact  between  it  and 
copper  lead  wires.  It  was  not  found  pos- 
sible to  solder  to  the  sulfide  directly  and 
brass  clamps  are  not  desirable,  but  it  was 
found  possible  to  silver-plate  the  ends  of  a 
piece  in  a  silver-potassium-cyanide  solution. 
After  this  is  done  a  copper  wire  can  be 
soldered  on  with  little  difficulty. 

When  the  sulfide  is  rolled  at  room  tem- 
perature it  has  a  large  negative  temperature 
coefficient  of  resistance,  similar  to  an  elec- 
trolyte. When  worked  at  200° C  the  tem- 
perature coefficient  is  approximately  zero. 
It  is  not  easy  to  explain  why  the  mechanical 
working  makes  so  great  a  difference  in  the 
electrical  properties,  but  it  seems  likely  that 
rolling  at  room  temperature  may  produce 
minute  cracks,  whereas  wire  which  is  drawn 
hot  is  probably  homogeneous. 

The  material  rolled  at  room  temperature 
was  found  to  have  different  resistance 
when  tested  with  direct  and  alternating  cur- 
rent. When  alternating  current  is  applied 
the  resistance  increases,  when  direct  cur- 
rent is  applied  the  resistance  decreases  but 
shows  a  tendency  to  recover  upon  standing. 

The  specific  resistance  at  25°G  was  found 
to  be  17,300  microhm-centimeters  or  about 
10,000  times  the  resistivity  of  copper. 

As  resistance  measurements  indicated 
electrolytic  conduction  of  the  cold-rolled 
strips,  experiments  were  made  to  discover 
any  electrochemical  decomposition.  Direct 
current  was  applied  to  a  strip  having  cop- 
per leads  soldered  to  its  silver-plated  ends. 
An  initial  current  of  25  milliamperes  gave 
no  visible  effect.  The  current  was  increased 
at  intervals  until  with  200  milliamperes  a 
discoloration  of  the  plate  at  the  anode  end 
was  noticed.     A  still  larger  current  ap- 


peared to  destroy  the  silver  plating  and 
finally  burned  off  the  terminal,  but  before 
this  happened  a  myriad  of  little  shiny  silver 
crystals  appeared  on  the  black  surface  of 
the  sulfide  as  shown  in  Fig.  1.  The  ap- 
pearance of  these  crystals  was  studied  under 
the  microscope  and  it  was  found  that  they 


Fig.  2.  Anode  End  Showing  Where  the 
Terminal  Burnt  Off.  After  the  Silver  Plating 
Was  Destroyed  by  the  Sulfur,  the  Outcrop- 
ping of  Silver  Took  Place.  Magnified  50 
Diameters. 

occurred  to  within  a  small  fraction  of  a 
millimeter  of  the  anode  terminal  as  shown 
in  Fig.  2.  The  appearance  of  some  of  these 
crystals  suggested  that  they  had  been  ex- 
pelled from  the  interior  of  the  strip  with 
considerable  force.  The  strip  appeared  to 
be  made  up  of  a  multitude  of  tiny  electro- 
lytic cells  between  which  metallic  conduc- 
tion occurred.  The  cross-section  of  this 
strip  was  0.3  by  0.01  centimeter. 


A  25-MILE  BATTERY  LAMP  SIGNAL 
PROJECTOR. 

A  very  simple  signal  projector  having  a 
range  of  some  twenty-five  miles  is  shown 
in  the  illustration  herewith.  It  consists  of 
a  wooden  box  12  in.  long  and  5  in.  square, 
made  of  *4-in.  wood.  This  box  contains 
a  5-in.  Mangin  mirror. 

At  the  focal  point  of  this 
mirror  is  mounted  a  6-volt, 
1^2-ampere  Mazda  lamp,  hav- 
ing a  maximum  concentration 
filament.  (A  \l/2  ampere  auto- 
mobile lamp  could  be  used,  but 
the  range  will  not  be  so  great 
as  with  the  maximum  concen- 
tration filament  lamp.)  In  the 
lower  compartment  of  the  box 
are  four  standard  dry  batteries 
connected  in  series  and  to  the 
lamp  thru  a  standard  tele- 
graph key. — Photo  Courtesy 
Gen.  Elec.  Rev. 


ceed  1  per  cent.  Various  arrangements  of 
carbons  with  a  view  to  avoiding  the  shadow 
cast  by  the  negative  have  been  tried,  but 
with  the  present  lens  systems  it  is  difficult 
to  utilize  more  than  17  per  cent,  of  the 
light  from  the  crater.  On  the  other  hand, 
it  is  suggested,  an  improvement  might  be 
made  by  reverting  to  an  old  idea  explained 


in  a  Swiss  patent  by  S.  Schuckert,  as  far 
back  as  1889.  This  involves  the  use  of  an 
ellipsoidal  mirror,  the  crater  being  at  one 
focus,  the  objective  lens  at  the  other,  and 
the  film  in  between.  Theoretically  as  much 
as  75  per  cent,  of  the  light  from  the  crater 
can  thus  be  collected. 


AS  TO  THE  EFFICIENCY 
OF  OPTICAL  PRO- 
JECTION. 

In  a  recent  paper  before 
the  Illuminating  Engineering 
Society,  Mr.  R.  B.  Chilas 
analyzes  the  conditions  affect- 
ing the  efficiency  of  optical 
projection  in  the  cinemato- 
graph. He  estimates  that  in 
the  most  favorable  circum- 
stances the  screen  does  not  re- 
ceive more  than  5.8  per  cent. 
of  the  light  from  the  arc,  while 
in  many  cases  it  does  not  ex- 


A  Military  Signal  Projector  Having  a  Range  of  25  Miles.    It  Is 
Fitted  with  5-ln.  Mangan  Mirror  and  6-Volt  12-c.p.  Mazda  C 
Lamp.    A  Telegraph  Key  Controls  the  Lamp  Circuit. 


RUSSIAN  SOLDIERS 
AMAZED  AT  WIRELESS. 

'  An  interesting  description  is 
given  by  a  Russian  officer  of 
one  of  the  numerous  little  mo- 
bile field  wireless  outfits  oper- 
ating near  the  front.  The 
whole  wireless  station  can  be 
unloaded  from  its  auto  truck, 
rigged  up  and  be  ready  for 
work  in  twenty  minutes.  The 
^eventy-foot  masts  are  hollow 
and  made  in  sections,  which  are 
screwed  together  when  taken 
off  the  truck. 

The  simple  peasant  soldiers, 
many  of  whom  come  from  re- 
mote villages  where  wireless 
has  never  been  heard  of,  are 
greatly  fascinated  by  the  sta- 
tion, and  like  to  stand  around 
when  they  can  get  a  chance  and 
watch  the  flashing  of  the  spark 
and  listen  to  its  song.  "It 
sounds  like  butter  in  a  frying 
pan,"  they  say.  They  have 
coined  a  nickname  for  the  men 
in  the  wireless  crew,  which, 
as  near  as  possible  in  English, 
is  "sparkers"  or  "the  spark 
men." 


386 


THE  ELECTRICAL  EXPERIMENTER 


October,  1917 


Experimental  Physics 


By 

JOHN  J.  FURIA,  A.  B.,  M.  A.  (Columbia  University) 


LESSON  8. 
Light. 

MOST  people  have  the  erroneous 
idea  that  light  passes  instantan- 
eously from  the  source  to  the 
observer.  In  the  year  1675  Olaf 
Roemer,  a  Danish  astronomer, 
found  that  his  prediction  of  an  eclipse  was 


Due  to  the  Difference  In  Time  Elapsed  Be- 
tween the  Eclipses  of  One  of  Jupiter'* 
Moons,  Roemer  In  1675  Deduced  That  This 
Deviation  Was  the  Time  Required  for  Light 
to  Travel  Across  the  Earth's  Orbit. 

in  error.  He  had  observed  and  noted  care- 
fully the  instant  when  one  of  Jupiter's 
moons  M  (Fig.  35)  past  into  Jupiter's 
shadow  when  the  earth  was  at  E,  and  by 
computation  predicted  the  exact  instant 
when  another  eclipse  should  occur  six 
months  later  when  the  Earth  was  at  E1. 
Actually  the  eclipse  occurred  996  seconds 
later  than  at  the  time  predicted,  and  Roemer 
concluded  that  the  delay  represented  the 
time  required  for  the  light  to  travel  across 
the  Earth's  orbit,  a  distance  which  was 
known  to  be  about  180,000,000  miles.  Thus 
it  was  found  that  light  travels  about  186,000 
miles  per  second.  This  speed  is  so  great 
that  it  would  carry  light  nearly  eight  times 
around  the  Earth  in  one  second,  so  it  is  no 
wonder  that  the  idea  prevails  that  light 
travels  instantaneously.  However  to  the 
astronomer  who  deals  with  the  enormous  in- 
terstellar distances  the  speed  of  light  seems 
as  the  speed  of  a  1903  model  Ford  with  only 
one  cylinder  in  working  order.  It  takes  4 
and  one-half  years  for  light  to  travel  from 
the  earth  to  the  nearest  star.  If  one  of  us 
should  be  up  on  the  Pole  star  with  a  tele- 


 t\ 

/r  !  /\ 


tic  j 

i 

N 

Fig.  36 


The  Principle  of  Light  Reflection;  Angle  "i", 
Incident    Angle    Always    Equals    "r",  the 
Angle  of  Reflection. 

scope  powerful  enough  to  see  events  on  the 
earth,  he  would  not  see  the  battle  of  Gettys- 
burg, which  occurred  July,  1863,  until  Jan- 


uary, 1918,  the  Pole  star  is  so  far  away. 

EXPERIMENT  46.  One  of  the  most 
important  properties  of  light  is  that  of  re- 
flection. When  a  billiard  ball  strikes  the 
sides  of  the  table  obliquely,  it  rebounds  in 
such  a  manner  that  the  angle  made  by  the 
ball  on  striking  and  the  angle  made  on  re- 
bounding are  equal.  In  Fig.  36,  A  is  the 
position  of  ball  before  being  struck  by  the 
cue,  B  is  the  point  on  the  cushions  of  the 
billiard  table  where  the  ball  strikes,  and  C 
is  the  position  of  the  billiard  ball  after  re- 
bounding. Angle  1  equals  angle  2.  If  BN 
is  a  line  perpendicular  to  the  cushion,  angle 
i  equals  angle  r.  Angle  i  is  called  the  in- 
cident angle  and  angle  r  the  angle  of  reflec- 
tion. The  law  of  reflection  is  usually  stated 
THE  ANGLE  OF  INCIDENCE  IS 
EQUAL  TO  THE  ANGLE  OF  REFLEC- 
TION. The  fact  that  the  law  of  reflection 
holds  true  for  light  makes  possible  the  use 
of  many  instruments,  one  of  the  most  im- 
portant at  the  present  time  being  the  peri- 
scope. The  writer  learned  the  law  of  re- 
flection at  school  long  ago  on  those  occa- 


How  a  Person  at  "E"  Can  See  a  Candle,  In- 
visible at  "C",  and  Apparently  Burning  In- 
side a  Bottle  of  Water  at  "M." 

sions  when  the  sun  shone  into  the  room  and 
the  teacher  pulled  down  the  shades.  A  beam 
of  sunlight  would  enter  the  room  from  the 
sides  of  the  shades  and  the  writer  by  means 


Illustrating  the  Principle  of  the  Submarine's 
Periscope.    Mirrors  Reflect  the  Image  Down 
the  Tube  and   Around  Corners. 

of  a  pocket  mirror  would  reflect  it  so  that 
the  angle  of  incidence  being  equal  to  the 
angle  of  reflection,  and  the  teacher's  face 
being  along  the  angle  of  reflection,  it  would 
become  illuminated,  to  the  extreme  discom- 
fort of  the  teacher  and  the  unbounded 
pleasure  of  the  pupils.  Things  would  have 
fared  very  well  had  not  the  teacher  also 
known  the  law  of  reflection,  and  hence  been 
able  to  locate  the  innocent  culprit.  (Inno- 
cent according  to  the  pupils,  and  culprit  ac- 
cording to  the  teacher.)  When  a  surface  is 
smooth  as  in  the  case  of  a  mirror  each  point 
of  an  object  is  regularly  reflected,  and  a 
sharp  image  is  formed.   When  the  reflector 


is  rough,  as  in  the  case  of  ordinary  paper 
or  the  walls  of  a  room,  each  particle  of  the 
surface  reflects  regularly,  but  since  the  par- 
ticles are  not  all  on  a  level  stretch,  the  re- 
flected light  is  scattered,  and  this  is  known 
as  diffuse  reflection.  Some  girls'  noses  are 
smooth  and  shiny  (regular  reflection)  but 


Analysis  of  the  Principle  of  Mirrors.  Each 
Point  of  An  Image  In  a  Plane  Mirror  Is  As 
Far  Behind  the  Mirror  As  the  Corresponding 
Point  of  the  Object  Is  In  Front  of  the 
Mirror. 

after  an  application  of  face  powder,  the 
noses  are  no  longer  smooth  and  shiny  but 
rough  (diffused  reflection).  The  Sun,  a 
gas  flame,  etc.,  are  visible  because  of  the 
light  they  emit,  while  ourselves,  books, 
chairs,  tables,  etc.,  are  visible  because  of  the 
light  reflected.  All  bodies  except  those  emit- 
ting light  are  visible  because  of  the  light 
they  reflect  diffusely. 

When  light  meets  the  eye  from  a  polished 
surface  we  do  not  see  the  surface.  Hence 
it  is  possible  at  Coney  Island  to  create  a 
great  deal  of  amusement  by  having  "mazes" 
(smooth  polished  plate  glass)  into  which 
the  unsuspecting  victim  will  walk.  Black 
bodies  send  no  light  to  the  eye  but  they  can 
be  seen  because  their  outlines  are  disting- 
uished by  the  light  which  comes  from  the 
background. 

EXPERIMENT  47.  To  locate  the  image 
of  an  object  in  a  plane  mirror.  Stand  a 
small  rectangular  pocket  mirror  on  its  side, 
over  a  piece  of  paper.  Draw  an  arrow  in 
front  of  the  mirror  MM  at  AB.  If  now 
the  eye  is  placed  behind  A,  behind  B  and  to 
the  right  of  B  respectively,  in  the  positions 


f/g.  40 


Due  to  the  Change  of  Velocity  of  Light  Rays 
Passing  Thru  a  Denser  Medium — Water  In 
This  Case — An  Object  Appears  As  Tho  Bent 
or  Misplaced. 

Ei,  E2,  E3,  the  image  A1  of  the  point  A,  will 
be  found  on  the  straight  line  EiA  prolonged 
{Continued  on  page  424) 


October,  1917 


THE   ELECTRICAL  EXPERIMENTER 


387 


Radio-Controlled  Torpedo  Devised  by  California  Genius 


A WIZARD  of  electricity,  whose  in- 
ventions may  revolutionize  warfare 
both  on  land  and  sea  and  win  vic- 
"<  tory  for  America  in  the  great  war 
against  Germany,  was  discovered 
in  the  person  of  Henry  H.  Hyder,  of  Los 
Angeles,  Calif.,  ostensibly  an  automobile 
man,  but  in  reality  a  miracle  worker  with 
wireless  and  electricity. 

Seated  in  his  little  workshop  several 
miles  away,  Hyder  can  explode  any  one  of 
a  field  of  mines,  either  in  the  ocean  or  on 
land.  He  can  choose  which  mine  to  ex- 
plode or  he  can  blow  them  all  up — by  wire- 
less. No  other  wireless  can  interfere  with 
his  to  set  the  mine  off  prematurely  or  to 
prevent  the  explosion.  (We  are  not  so  sure 
about  this. — Editor.) 

In  the  same  way  Hyder  can  release  a 
torpedo  at  a  ship  twenty  miles  off  the  coast, 
choose  the  time  to  explode  it  or  in  case  it 
fails  to  reach  its  mark,  lock  the  torpedo, 
prevent  the  explosion  and  bring  the  costly 
instrument  back  to  the  place  from  which 
it  started. 


It  may  be  the  means  of  dealing  the  death 
blow  to  the  submarine  menace. 

It  is  possible  that  it  will  mean  the  scrap- 
ping1 of  the  giant  super-dreadnaughts  of 
the  world's  great  navies  because  of  their 
helplessness  when  attacked  by  a  torpedo 
controlled  in  every  way  by  wireless.  It  will 
also  mean  a  great  saving  in  that  an  ex- 
pensive torpedo  which  misses  fire  can  be 
brought  back  and  used  again. 

Hyder  is  only  33  years  old  and  he  was 
born  on  a  farm  in  Missouri.  All  of  his 
electrical  knowledge  has  been  obtained  thru 
his  own  efforts,  for  neither  he  nor  his  as- 


dio  Electrician,  applicants  must  be  able  to 
receive  at  least  ten  words  per  minute  in 
the  continental  code,  write  legibly  and  spell 
correctly  at  the  rate  of  twenty-five  words 
per  minute,  and  have  a  grammar  school 
knowledge  of  arithmetic. 

(b)  To  be  enrolled  as  Electricians  3d 
Class  (Radio),  applicants  must  qualify  as 
in  (a)  and  must  be  competent  first  grade 
commercial  and  amateur  operators  who  can 
receive  twenty  words  per  minute  in  the 
continental  code. 

(c)  To  be  enrolled  as  Electricians  2nd 
Class  (Radio),  applicants  must  have  com- 
mercial licenses,  must  have  served  at  least 
one  year  as  radio  operators  on  merchant 
ships  with  a  discharge  from  such  ships, 
showing  excellent  service  and  good  reasons 
for  such  discharge,  and  must  be  able  to 
receive  in  continental  and  American  Morse 
code  at  the  rate  of  twenty-five  words  per 
minute. 

(d)  To  be  enrolled  as  Electricians,  1st 
Class  (Radio),  applicants  must  qualify  as 
in  (c)  and  must  be  radio  operators  who 


_..     -   ...       .      _  .   _.        .  Photos  from  C.  W.  Geicer 

This  California  Radio  and  Electrical  Inventor  Claims  to  Have  Solved  Many  Problems  of  Great  Value  to  U.  S.  War  Department.    He  Has 
Succeeded  In  Lighting  Lamps  by  Wireless  Power  and  Has  Perfected  a  Radio-Controlled  Torpedo  Which  Cannot  Be  Interfered  With. 


All  of  these  things  that  he  claims  to  be 
able  to  do  he  demonstrates  with  working 
models  in  his  little  workshop  with  the  help 
of  his  assistant,  Arthur  H.  McClelland. 

For  more  than  four  months  Hyder  and 
his  assistant  have  been  working  night  and 
day  to  perfect  the  invention  so  that  they 
can  take  it  to  Washington  to  place  it  before 
the  Naval  Advisory  Board.  Now  they  are 
about  ready  to  demonstrate  it  and  expect  to 
leave  for  Washington  within  a  short  time. 

The  invention  for  which  Hyder  claims 
so  much  is  not,  however,  the  result  of  only 
four  months'  work;  it  is  the  culmination 
of  fifteen  years  of  hard  study  and  drudgery, 
inspired  by  enthusiasm  and  hope.  Team 
work  has  played  an  important  part,  for 
McClelland,  Hyder's  assistant,  has  worked 
with  him  during  all  of  the  fifteen  years. 

Hyder's  torpedo  and  mine  construction 
have  not  been  his  only  accomplishment.  He 
has  perfected  a  system  of  lighting  lamps 
by  wireless  which  he  believes  will  be  utilized 
in  the  future  to  prevent  ships  from  col- 
liding in  the  fog  and  will  eliminate  the  block 
system  on  the  railways.  By  wireless  he 
can  light  several  lamps  wired  in  series  and 
keep  part  of  them  lighted  when  some  of 
them  are  removed. 

What  Hyder  terms  his  torpedo  and  mine 
construction  is  most  important  at  this  time. 


sistant  went  to  college — but,  then,  neither 
did  Edison.    Study  will  solve  all  problems. 


MR.  AMATEUR,  "I  WANT  YOU!" 
SAYS  UNCLE  SAM. 

UNCLE  SAM  is  offering  exceptional 
opportunities  to  young  men  who  will 
join  the  service  at  this  time,  states 
Mr.  Fred  Mueler,  Gunner  (R)  U.  S.  N. 
R.  F.  At  the  present  time  the  U.  S.  Navy 
Department  desires  to  enroll  in  the  U.  S. 
Naval  Reserve  Force  radio  men  who  are 
willing  to  volunteer  for  general  sea  ser- 
vice and  who  possess  the  following  quali- 
fications : 

(a)  Must  be  citizens  of  the  United 
States. 

(b)  Must  be  able  to  pass  a  physical  and 
mental  examination  before  enrollment. 

(c)  Must  be  able  to  send  and  receive  the 
continental  code  'and  possess  some  tech- 
nical knowledge  of  radio-telegraphy.  Ra- 
dio men  are  particularly  desired  and  those 
applying  for  enrollment  as  radio  operators 
will  be  assigned  to  active  duty  upon  quali- 
fying. 

The  following  is  a  list  of  qualifications 
required  for  enrollment  in  the  various 
grades  of  radio  operator : 

(a)  To  be  enrolled  as  landsmen  for  Ra- 


have  served  at  least  two  years  on  a  mer- 
chant ship  and  possess  a  considerable 
knowledge  and  acquaintance  with  radio 
plants. 

(e)  To  be  enrolled  as  Chief  Electrician 
(Radio)  applicants  must  'qualify  as  in 
(d),  must  have  a  broad  knowledge  of  ra- 
dio-telegraphy, must  have  served  on  ocean- 
going steamers  for  at  least  four  years,  and 
must  pass  an  examination  by  a  board  of 
at  least  three  officers,  of  which  two  shall 
be  radio  operators. 

The  rates  of  pay  for  the  above  grades 
of  radio  operator  are  as  follows : 

Chief  Electrician  (radio)  $72.00 

Electrician  (radio)  1st  class.  61.00 
Electrician  (radio)  2nd  class  52.00 
Electrician  (radio)  3rd  class  41.00 
Electrician  (radio)  Landsman 

(for  training)    32.00 

Men  who  are  enrolled  in  any  of  the 
above  grades  will  be  assigned  to  active  duty 
under  instruction  at  one  of  the  U.  S.  Naval 
Reserve  Radio  Schools,  where  they  will  be 
given  a  course  under  experienced  Navy  in- 
(Continued  on  page  417) 


388 


THE  ELECTRICAL  EXPERIMENTER 


October,  1917 


Brown  University  Trains  Radio  Experts 


Brown  University  has  helped  to  train 
radio  experts  during  the  past  summer,  con- 
ducting a  radio  class  under  the  direction 
of  Professor  Arthur  E.  Watson,  instruc- 
tor of  electrical  engineering.    More  than 


and  write  them  down,  as  correctly  as  they 
can,  in  letters. 

Other  students  practise  with  telephone 
head  sets  operating  on  dummy  aerials. 
Prof.  Watson  has  strung  wires  from  one 


HOW  RADIO  SAVED  46  LIVES  OF 
TORPEDOED  VESSEL. 

The  fortitude  of  a  wireless  operator  in 
sticking  to  his  instrument  made  possible  the 
rescue  of  forty-six  men  out  of  fifty,  on  the 
American  steamship  Orleans  when  she  was 
torpedoed  unawares  by  a  German  subma- 
rine, according  to  Capt.  Allen  Tucker,  com- 
manding. 

"We  saw  nothing  and  heard  nothing," 
Capt.  Tucker  said,  "until  the  torpedo  struck 
us  amidships  and  burst  with  such  force  that 
it  seemed  to  tear  the  ship  asunder.  It  was 
a  fairly  clear  night,  but  the  water  was  very 
black.  I  gave  orders  to  launch  the  boats 
immediately,  and  we  got  all  but  one,  which 
had  been  smashed  by  the  explosion,  into 
the  water  in  record  time. 

"Meanwhile  L.  F.  Larson,  our  wireless 
operator,  was  sitting  up  in  his  cabin  and 
sending  off  S  O  S  calls  as  coolly  as  tho 
they  were  merely  commercial  messages.  He 
finally  got  into  radio  touch  just  as  the  stern 
began  sliding  under  the  water.  I  ran  in, 
pulled  him  out  on  deck  and  practically 
threw  him  overboard,  knowing  he  could 
swim.  Then  I  followed  and  we  both  swam 
like  hell  to  get  away  from  being  dragged 
under  the  sinking  ship. 

"The  Orleans  sank  within  ten  minutes." 


Radio  Students  At  Brown  University,  Providence,  R.  I.,  Studying  the  Ins  and  Outs  of  Wire- 
less Transmitting  Apparatus. 


half  a  hundred  amateurs  have  been  study- 
ing one  and  two  nights  a  week  under  Prof. 
Watson,  who  is  the  father  of  wireless  at 
Brown.  Almost  wholly  with  his  own  hands 
he  built  the  plant  on  the  hill  and  put  the 
college  on  the  wireless  map. 

Up  to  the  beginning  of  the  war  Brown 
had  one  of  the  best  college  wireless  plants 
in  the  East.  Prof.  Watson  and  his  stu- 
dents placed  the  apparatus,  strung  the 
wires;  in  short,  did  everything  except  build 
the  towers  on  Maxcy  and  University  Halls. 

The  apparatus  had  a  radius  of  between 
200  and  300  miles,  and  from  the  time  of 
its  installation  "listening  in"  was  a  sport 
that  attracted  many  students  who  pre- 
viously had  shown  little  interest  in  elec- 
tricity in  general  and  wireless  in  particu- 
lar. For  them  the  wires  far  above  the 
middle  campus  hummed  a  lively  and  en- 
gaging tune.  To  listen  to  it  once  was  to 
come  again  and  again.  • 

The  closing  of  the  plant  did  not  greatly 
interfere  with  the  training  of  future  oper- 
ators. Prof.  Watson  is  too  much  of  an 
enthusiast  to  let  such  a  trivial  matter  up- 
set his  efforts.  In  his  new  quarters  in  the 
Engineering  Building  he  straightway  set  up 
all  necessary  apparatus,  rigged  dummy 
aerials  and  kept  going  as  if  nothing  had 
happened. 

His  night  class  caught  this  enthusiasm. 
Its  students  have  been  eager  and  industri- 
ous. A  few  started  as  fair  amateur  oper- 
ators. Some  had  only  dabbled  in  the  art. 
The  larger  number  knew  nothing  at  all 
about  it.  But  in  the  10  weeks  everybody 
added  to  his  practical  knowledge  of  radio. 

Of  all  the  instruments  in  the  room  the 
omnigraph  sender  is  of  the  greatest  in- 
terest. It  is  a  small  mechanical  device 
havmg  metal  discs— a  whole  series  of  them 
fitting  one  on  top  of  the  other— that  show 
peculiar,  irregular  edges.  These  edges  are 
nothing  more  or  less  than  the  dots  and 
dashes  of  the  code.  As  the  discs  revolve 
the  listeners  pick  out  the  dots  and  dashes 


room  to  another  in  the  building  and  by 
means  of  them  the  more  advanced  stu- 
dents send  and  receive  messages.  The 
visitor  always  finds  it  interesting  to  ad- 
just the  headgear  and  listen  in  on  what 
may  be  coming  from  a  distant  corner. 

"We  hope  to  encourage,"  said  Prof.  Wat- 
son, in  a  recent  interview,  "the  formation 
of  groups  of  students  who  will  train  in 
sending  messages  as  well  as  in  receiving. 


KILBOURNE  &  CLARKE  CO.  GET 
U.  S.  RADIO  ORDER. 

This  concern  has  been  given  a  contract 
by  the  United  States  Navy  Department  for 
the  construction  and  delivery  within  nine 
months  of  250  additional  radio  transmission 
telegraph  sets,  at  $988,000,  which  with  the 
other  contracts  from  the  Government  held 
by  the  company  makes  a  total  of  315  sets, 
at  a  cost  of  $1,112,000.  The  contract  calls 
for  200  one-kilowatt  and  50  two-kilowatt 
transmission  sets  for  the  use  of  the  Navy 
Department.  It  is  understood  some  of  these 
are  to  be  installed  on  naval  vessels,  while 
probably  the  most  of  the  order  will  be  for 
equipping  the  vessels  of  the  United  States 
Shipping  Board  Emergency  Fleet. 


Evening  Radio  Class  at  Brown  University.  E 

As  This  Pi 

Our  time  is  all  too  short  for  full  training, 
but  we  shall  try  to  give  every  student  a 
good  grounding  in  the  first  principles  and  to 
advance  the  real  amateurs,  the  ones  who 
have  worked  with  home  sets,  to  a  fair 
degree  of  proficiency." 


v  en  the  Young  Women  Have  Caught  the  Fever, 
cture  Shows. 


A  wireless  station  with  a  night  range  of 
700  miles  has  been  installed  at  Cape  May, 
N.  J.,  by  E.  M.  Murray,  a  Philadelphia 
Marconi  engineer,  and  E.  M.  Hartley  of 
the  Miami  station  will  be  superintendent. 


October, 


1917  THE  ELECTRICAL  EXPERIMENTER  389 


™*  RADIO  LEAGUE 


'/"AMERICA 


H.  Gernsback,  Manager 


HONORARY  MEMBERS 

CAPT.  WHG.  BULLARD.  U.S.N.  NIKOLA  TESLA 
PROF  REGINALD  FESSENDEN.    DR. LEE  DE  FOREST. 

W.  H.  Kirwan,  Master  of  Radio  Relays 


The  Amateur's  Opportunity 

By  the  EDITOR 


THE  letter  which  we  publish  here- 
with is  one  of  the  many  that  come 
to  the  editor's  desk  during  the 
:ourse  of  a  week. 
It  clearly  illustrates  one  of  the 
strangest  situations  created  by  the  war,  and 
it  likewise  has  a  very  pointed  moral.  The 
closing  of  America's  radio  stations  by  our 
Government  has  had  the  unfortunate 
result  in  bringing  to  life  several  hun- 
dred thousand  "sore  heads,"  who  in 
peace  times  were  fond  of  calling  them- 
selves Radio  Amateurs. 

These  good  people,  whose  patriotism 
has  suddenly  gone  bankrupt,  always 
forget  that  the  same  government  that 
granted  our  radio  amateurs  greater 
liberties  than  any  other  nation  on  the 
face  of  the  earth  certainly  has  some 
rights  of  its  own. 

Where,  Oh !  where,  is  our  far- 
famed  American  patriotism?  Where 
is  our  highly  lauded  fair-play?  Where 
is  our  gratefulness?  Sore-headedness 
seems  to  be  one  of  our  latest  acquired 
national  diseases — at  least  in  our 
American  radio  amateurs.  And  we 
cannot  but  condemn  it  in  the  harshest 
possible  terms. 

Why  not  make  the  best  of  it,  partic- 
ularly as  the  present  radio  situation  is 
of  course  only  temporary?  Sore- 
headedness  and  bitter  remarks  about 
the  Government  do  not  in  the  least  im- 
prove matters,  but  rather  tend  to  make 
them  worse.  We  all  want  our  stations 
back  after  the  war ;  we  all  want  the 
ether  free  for  all.  But  the  way  ama- 
teurs are  acting  now  certainly  tends 
to  bring  the  whole  fraternity  into  bad 
repute  at  Washington.  As  if  amateurs 
had  not  been  disliked  enough  before 
the  war,  with  all  the  Q.R.M.  nuisance  going 
on  in  the  ether  continuously !  Why  make 
ourselves  disliked  still  more?  What's  the 
matter  with  the  American  amateur  any- 
way? Where  is  his  logic? 
common  sense? 

And  last,  but  not  least, 
where  does  the  amateur 
come  in  with  his  silly,  non- 
sensical kicks  ?  What  about 
the  wireless  manufacturers 
who  have  been  put  out  of 
business  —  wiped     off  the 


Government?  Indeed  not,  they  gladly  do 
their  "bit"  for  their  country. 

Then  amateurs,  where  do  you  come  in? 
Now,  we  realize  that  this  is  rather  plain 
talk,  and  it  is  not  pleasant  to  write  it,  but 
truth  as  a  rule  is  never  pleasant  and  we 
hope  that  our  amateurs  will  see  that  we  are 
working  in  their  very  best  interest. 


U.  S.  Navy  Recruiting  station 

St  Louis.  Mo. 

Aug.  18,  1917. 


Mr.  H.  Gernsback, 

Editor  Bxperimenter  PubllBhing  Co. 
New  York  City,  H.Y. 

My  dear  Sir; 

The  United  3tatea  fiavy  Department  has  Instructed 
this  reoruiting  office  to  make  eve.-y  effort  to  enlist  men 
for  servioe  in  tho  radio  branch  of  the  Wavy. 

These  men  ere  wanted  immediately  for  aotlve  eer- 

Tioe. 

We  are  unable  to  find  a  complete  list  of  all  radio 
operators  in  the  3t.  Louis  District  which  comprises  the  en- 
tire state  of:  Missouri,  with  tho  exception  of  Jackson  and 
Buchanan  Cotrtles,  in  addition  to  two  oountloa  of  Illinois, 
Madison  and  3t.  Clair. 

One  of  your  subsorlboro  to  the  Blectrloal  ttrperlment' 
suggested  to  me  that  you  would  be  in  a  position  to  furniBh  uo 
with  a  complete  list  of  all  licensed  radio  operators  in  this 
district,  and  in  addition,  those  men  who  are  amateurs  but  wi.o 
have  not  yet  been  licensed. 

You  may  be  sure  that  any  information  given  ua  will 
be*nlghly  appreciated. 

Yours  very  truly, 


Lieutenant  U.3.B. 


Where  is  his 


The  Editor  of  this  journal  has  a  record 
of  having  championed  the  amateur's  cause 
ever  since  1908.  It  was  due  solely  to  his 
efforts  that  the  American  amateur  was  offi- 
cially recognized,  and  that  a  law  was  framed 


map?   Are  they  going  about 


the  land  lamenting  their 
cruel,  cruel  fate?  Not 
much.  They  know  that  war 
is  synonymous  with  sacri- 
fice. They  are  doing  their 
bit — their  big  bit,  rather. 

What  about  the  radio  and 
technical  magazines,  which  1  1 
lost  99%  of  their  wireless  |  1 
advertising?  Take  this  f  1 
magazine  for  instance,  1  I 
which  since  its  start  never   \  j 

made    any    money.     When    \  '  

war  was  declared  it  lost  : 
$1,200  worth  of  radio  advertising  in  a  heap, 
and  it  will  be  losing  this  amount  every  month 
as  long  as  the  war  lasts.  Have  these  maga- 
zines, the  Experimenter  included,  ever  as 
much  as  raised  their  voices  against  the 


AMATEURS   OF  AMERICA! 
I  Herewith  Propose 
"THE  RADIO  ROLL  OF  HONOR" 

I  call  upon  every  radio  amateur  in  America  to  do  his  "bit" 
in  this  war.  Amateurs,  this  is  the  most  important  message  to 
you  I  have  ever  written.  I  consider  it  more  important  than  my 
Editorial  in  the  November,  1908,  issue  of  "Modern  Electrics," 
which  was  the  direct  cause  of  placing  the  American  Radio 
Amateur  into  the  Radio  Law  of  1912,  thereby  giving  you  the 
free  use  of  the  ether.  Amateur  Wireless  owes  a  large  debt  to 
America.  Now  is  the  time  to  repay  that  debt  with  interest. 
Will  you  do  it? 


for  the  amateur's  benefit,  giving  him  the 
free  use  of  the  ether. 

The  Editor  will  continue  to  work  in  the 
interest  of  the  American  amateur,  but  he 
cannot  do  so  without  the  Iatter's  undivided 


interest  and  his.  full  enthusiasm.  It  is  not 
pleasant  to  work  for  a  lot  of  sore-heads, 
and  the  amateurs  certainly  do  not  wish  the 
Editor  to  wash  his  hands  of  the  whole 
matter,  and  "chuck  up  the  job"  in  disgust. 

What  we  want  is  ENTHUSIASM  and 
plenty  of  it ! ! !  Let's  pull  ourselves  together 
and  let  us  show  the  world  what  stuff  we 
are  made  of.  Let's  all  do  our  bit  in  this 
war,  to  make  the  world  free  and  safe 
forever.  To  do  it  Uncle  Sam,  besides 
his  soldiers  and  sailors,  needs  oper- 
ators—operators and  then  some.  We 
have  them.  Thousands  of  them.  The 
country's  full  of  'em.  The  order  of 
the  day  is  to  get  them  out  into  the 
open.  And  we'll  do  our  best,  or  perhaps 
our  worst,  to  get  them  to  come  out. 

Uncle  Sam  just  now  does  not  re- 
quire radio  experts  so  much  who  can 
send  and  receive  50,000  words  a  min- 
ute ;  rather  he  wants  boys  who  have 
a  fair  knowledge  of  radio  and  who 
like  the  work.  Your  Uncle  Samuel 
will  make  an  expert  out  of  you  in 
no  time,  and  he  will  pay  you  while  he 
is  doing  it.  Radio  work  in  the  army 
and  navy  is  comparatively  safe,  and 
while  we  do  not  in  the  least  wish  to 
imply  that  radio  amateurs  are  cowards, 
we  do  wish  to  go  on  record  with  the 
statement  that  as  a  rule  the  radio 
man  stands  on  a  higher  plane  of  in- 
telligence than  the  average  plain  sol- 
dier or  sailor. 

Recognizing  this,  Uncle   Sam  pays 
the  radio  operators  and  signal  corps 
men  more  money  than  to  the  soldier 
or  sailor  of  the  rank  and  file.  Now 
if  this  does  not  spell  opportunity  for 
you,  we'll  eat  a  5-K.W.  transformer, 
spark  gap,  wires  and  all ! 
Amateurs,  again  we'll  tell  you,  you  don't 
realize  how  really  valuable  you  are  to  vour 
country.    So  why  hide  yourselves  away? 

Now  then,  here  is  our  plan,  and  we  ex- 
pect full  co-operation  from  every  one  of 

 ,  „,„  you,  even  if  you  can't  send 

 i  in  ==  I'  or  receive  more  than  five 

1  1  dots  and  six  dashes  per 
|  |   minute  ! 

1  1  We  are  going  to  compile 
1  |  the  most  complete  file  of 
Radio  Amateurs  in  the 
country,  who  are  willing  to 
do  their  "bit."  The  files  of 
the  "Radio  League  of 
America"  now  contain  some 
16,600  name  s — a  pitiful 
amount  compared  to  the 
total  of  some  300,000  ama- 
teurs. 

We  want  this  list  so  that 
when  Uncle  Sam  writes  to 
the  Editor  asking  him  for 
names  of   radio  operators, 
1  |   we  will  be  in  a  position  to 
I  I   send  him  thousands,  where 

 ' ' "  1    we    send     him  dozens 

now.  Take  for  instance 
the  letter  publisht  here ;  all  we  could  send  to 
L't.  C.  H.  McCann  was  forty  names.  A  fine 
showing,  that — not !  Now  to  make  it  in- 
teresting for  you,  amateurs,  beginning 
(Continued  on  page  415) 


390 


THE  ELECTRICAL  EXPERIMENTER 


October,  1917 


A  Radio  Controlled  Model  Boat 


FROM  time  to  time  in  the  Electrical 
Experimenter  we  have  read  articles 
on  wireless  control.  We  have  taken 
much  interest  in  publications  along 
this  line,  having  constructed  a  selec- 
tive control  set  in  the  summer  of  1916  our- 
selves ;  yet  we  have  not  run  across  a  set 


By  H.  C.  Van  Benthuysen  and  Max  I.  Black 

structed.  The  controlling  apparatus  is  an 
ordinary  coherer  set,  the  relay  of  which 
actuates  a  sounder  to  which  is  attached  a 
ratchet  wheel  control  for  a  second  sounder. 
This  second  sounder  operates  an  eight- 
point  rotary  switch  of  the  commutator  type. 
When  used  in  the  boat  two  segments  of 
this  switch  are  blank.  The  other  six 
operate  two  solenoid  reversing  switches 
and  one  solenoid  cut-off,  which  controls 
the  helm  motor  only.  It  is  possible  to  use 
the  two  blank  segments  for  a  solenoid  cut- 
off for  the  propeller  motor  altho  we  did 
not  find  it  necessary.  The  order  of  the 
points  are : — "reverse"  "forward"  "on" 
"starboard,"  "port"  and  "off."  The  "on" 
and  "off"  control  the  helm  motor  so  it  will 
not  be  in 


Appearance  of  Model  Boat  Fitted  With  Wire- 
less Control  Apparatus.  This  Kind  of  Work 
Is  Bound  to  be  Highly  Remunerative  and 
Radio  Experimenters  Will  Do  Well  to  Inves- 
tigate the  Many  Unsolved  Problems  In  This 
Field. 

that  has  mentioned  as  great  a  range  of  use, 
this  set  having  been  used  in  a  small  dem- 
onstration wireless  controlled  boat,  con- 
trolling toy  reversible  electric  trains,  shoot- 
ing fireworks — in  fact  it  can  be  used  with 
any  machine  which  is  controllable  by  elec- 
tricity. 

In  July,  1916,  this  apparatus  was  installed 
in  a  six-foot  electrically  propelled  boat  and 
on  the  4th  of  that  month  a  demonstration 
of  "The  Wireless  Control  of  a  Boat"  was 
given  at  Riverside  Park,  on  the  James 
River,  at  Mitchell,  S.  D.  In  April,  1917, 
the  same  apparatus  was  used  for  a  dem- 
onstration and  talk  on  the  "Science  of  Tel- 
automatics,"  given  before  the  Mitchell  Sci- 
'  ence  Club,  a  branch  of  the  South  Dakota 
Academy  of  Science. 

This  selective  set  is  simple  and  easily  con- 


r?a tenet  Wheel 


lamp  card  soldered 
to  segments 

forward 

B/anf 
5witct>orm 
'attached  to 
ratchet  wheel 

On 

Starboard 


Commutator 


ers  of  No.  24  D.C.C.  magnet  wire.  Wrap 
the  whole  coil  with  a  layer  of  tape.  The 
armature  is  an  iron  rod  about  five  inches 
long  and  just  large  enough  to  slide  easily 
in  the  core  of  the  solenoid.  The  solenoids 
are  placed  in  such  a  position  on  a  suitable 
base  that  when  the  armature  is  clear  in, 
the  end  will  be  about  one-half  inch  from 
the  outside  end  of  the  core. 


IOWA  STATE  UNIV.  WILL  TRAIN 
ARMY  TELEGRAPHERS. 

In  response  to  a  request  from  the  central 
department  signal  office  of  the  United 
States  Army,  the  Iowa  State  University 
will  give  during  the  next  school  year  a 


Detail  of  Sounder  and  Ratchet  Wheel  Mech- 
anism for  Successively  Switching  In  and  Out 
of  Circuit  the  Rudder  Control  Magnets,  Pro- 
peller Control,  Etc. 


7/\er/al 


Sounder 


Decoherer 


ft 


ope  ration 
continuous- 
ly. The  helm 
motor  is 
geared  down 
by  means  of 
a  worm 
drive  which 
also  keeps 
the  rudder 
rigid.  This 
also  gives 
the  operator 
a  chance  to 
skip  over  the 
starboard 
and  port 
without  al- 
tering the 
course  of  the 
boat.  With 
this  arrange- 
m  e  n  t  the 
operator  has 
complete 
control  over 
the  boat. 

For  the  se- 
lective con- 
t  r  o 1  of  a 
m  i  n  iature 
electric  train 
a  four -rail 
track  is  used 
(two  rails 
for  the  field 
and  two  for 
the  brushes 
so  the  train 
may  be  re- 
versed). 
With  only 
one  revers- 
ing switch 
being  neces- 
sary, thus 
giving  four 
blank  points 
on  the  eight- 
point  rotary  switch,  instead  of  two,  as  in 
the  case  of  the  boat.  With  these  connec- 
tions switching  can  be  demonstrated  with  a 
toy  electric  train. 

The  radio  apparatus  is  made  up  of  a  pre- 
cision coherer,  and  a  fifty  ohm  pony  relay 
with  an  ordinary  bell  decoherer.  The 
sounder  switches  are  any  ordinary  fifty 
ohm  sounders  with  an  extension  arm  which 
operates  a  ratchet  wheel.    (See  diagram.) 

The  solenoid  magnets  for  the  reversing 
switches  and  the  cut-off  switch  are  made  of 
a  core  consisting  of  one  layer  of  zinc 
(wound  on  a  pencil  for  uniform  diameter). 
Each  core  is  about  three  inches  long.  The 
ends  are  split  and  folded  out  to  hold  on 
the  fiber  ends  of  the  coil.  When  the  core 
and  ends  are  assembled  wind  on  three  lay- 


Blontr 


Sounder  fi/'i 


forward 


I  Propeller  Control 
forward 


I  II 


51orboord 


f 


fori 


8 


A 'elm  control 


f rope/1  er  pottery 


Held 


-III 


ft  elm  t>ct/fer(/ 


© 


i  av  Out  of  Circuits,  Including  Coherer  and  Sensitive  Relay,  As  Successfully 
bled  In  the  Radii  Control  of  the  Model  Boat  Illustrated  and  Described  In  the 

Present  Article. 

course  of  training  for  telegraphers  and 
wireless  telegraphers.  The  work  will  be  in 
charge  of  the  head  of  the  electrical  engi- 
neering department  and  will  be  open  to 
young  men  of  the  state,  without  regard  to 
entrance  requirements  usually  made  of 
students  by  the  University.  The  course 
for  the  individual  will  last  only  until  he 
has  mastered  the  art  of  telegraphy  suffi- 
ciently to  pass  the  government's  examina- 
tion in  the  subject. 

"The  need  of  telegraphers  in  the  signal 
corps  is  serious,"  declared  Lieut.  Col.  Wild- 
man  in  a  letter  to  President  Jessup.  "The 
available  supply  has  been  exhausted  and 
new  men  must  be  trained  to  complete  the 
present  organization  and  prepare  for  all 
future  increase." 


October,  1917 


THE  ELECTRICAL  EXPERIMENTER 


391 


Measurements  of  Radio  Antenna  on  Shipboard 
and  Some  Interesting  Comparisons 

By  F.  A.  HART 


nary  shade.    Rollers  can  be  obtained  of  any 
length  for  a  nominal  price. 
Contributed  by   CARL  BERNHARDT. 


Variations  of  capacity,  inductance  and 
fundamental  wave-length  have  been  selected 
by  the  author  from  measurements  taken 
on  a  large  number  of  vessels,  and  covering 
at  the  same  time  as  broad  a  range  as  pos- 
sible. These  data  should  be  of  interest  to 
marine  engineers  and  advanced  experimen- 
ters, especially  in  the  case  of  aerials  erected 
on  roofs,  such  aerials  being  under  very 
similar  conditions  as  regards  effect  from 
near-by  metal,  stays,  etc.,  which  materially 
affect  the  capacity  of  the  aerial. 

In  connection  with  ship  stations  a  great 
deal  has  been  said  about  compass  trou- 
bles, generally  attributed  by  masters  to 
the  nearness  of  the  aerial  lead-in  wires  in 
each  specific  case.  It  might  be  well  to 
point  out  that  exhaustive  tests  have  been 
made  from  time  to  time,  and  absolutely 
no  disturbance  noticed,  says  F.  A.  Hart 
in  The  Electrician,  London.  On  the  other 
hand,  the  proximity  of  a  motor-generator  or 
other  large  mass  of  iron  to  the  compass 
would  tend  to  have  some  effect. 

The  lengths  used  in  the  table  are  given 
in  feet,  capacity  in  micro-farads,  inductance 
in  centimetres  and  natural  wave-length  in 
meters. 

For  simplicity,  each  type  is  designated 
by  a  number.  The  overall  or  total  length 
of  wire  from  apparatus  of  the  "L"  aerials 
is  taken  as  the  horizontal  plus  the  vertical, 
and  in  the  "T"  aerials  half  the  horizontal 
plus  the  vertical.  All  these  aerials  are 
comparatively  small  in  actual  amount  of 
wire  compared  with  aerials  in  coast  sta- 
tions, and  a  good  many  should  compare 
very  nearly  with  many  amateur  receiving 
aerials,  some  of  which  are  of  even  greater 
length. 

Aerials  such  as  Nos.  6,  9  and  28  are  the 
least  efficient  for  200  and  300  metre  waves, 
as  the  fundamental  is  very  large,  the  ca- 
pacity low,  the  radiation  resistance  high ; 
and  in  order  to  reduce  the  aerial  to  small 
wave-lengths  the  series  condenser  would 
have  to  be  less  than  0.0004  mfd.  As  both 
capacities  are  so  small,  the  radiation  from 
any  set  less  than  one  kilowatt  would  prob- 
ably not  be  greater  than  one-half  ampere. 
Judging  by  the  results,  for  those  who  wish 
to  transmit  efficiently  on  200  or  300  meters, 
the  aerial  should  be  made  a  "T"  where  the 
horizontal  length  is  120  ft.  or  over.  As 
a  rule,  the  most  efficient  working  wave- 
length where  a  series  condenser  is  not 
used  is  about  0.9  of  the  natural  wave-length. 
For  instance,  in  the  case  of  No.  23  the 
natural  is  230;  taking  0.9  of  this  value 
and  adding  it  to  230  we  get  437,  which 
should  give  the  greatest  radiation  for  that 
particular  size  of  aerial. 

In  the  case  of  Nos.  15  and  16,  these 
measurements  are  identical,  with  the  excep- 
tion of  a  trifle  greater  height  and  55  ft. 
more  wire  in  the  horizontal  length  of  No. 
16.  Everything  being  equal  in  both  cases, 
except  the  relation  of  the  vertical  wires 
to  the  bridge  railings  and  metal  stay  in  No. 
15,  this  apparently  makes  up  for  the  55 
ft.  of  extra  length  in  No.  16. 

The  most  marked  of  deck  and  work  ef- 
fects is  in  Nos.  38  and  39,  the  vertical 
length  in  No.  39  running  parallel  with 
three  stays  from  the  top  of  the  mast  to 
the  wireless  cabin.  In  No.  38  they  run 
practically  the  same,  also  considerably  in- 
creased by  the  nearness  of  the  funnel.  The 
"T"  type  aerial  has  been  found  as  a  whole 
to  give  the  best  all-round  results,  and  is 
less  likely  to  be  affected  by  foreign  mat- 
ters. The  spring  stay  should  be  removed 
and  all   other   stays   either   grounded  or 


broken  up  with  insulators  to  ensure  against 
induction  and  the  most  effective  work 
from  the  radio  apparatus. 

Aerials  in  which  stays,  decks  or  other 
metal  work  figure  largely  are  Nos.  18,  19, 
20,  21,  22,  30,  33,  34,  35,  36  and  37,  in  every 
case  affecting  the  vertical  length.  The 
ground  lead  in  all  examples  given  does  not 
average  over  3  ft.,  and  is  sometimes  less. 

No.  1  is  a  very  good  type  of  aerial  for 
amateurs  who  wish  to  transmit.  No.  40 
is  also  in  line  with  No.  1 ;  the  capacity 
runs  higher,  altho  the  lengths  are  very 
small,  and  the  nearness  to  all  metal  work 
and  the  large  number  of  wires  has  helped 
to  increase  this. 

One  can  readily  see  from  the  table  how 
important  it  is  to  keep  the  overall  lengths 
as  small  as  possible  where  there  is  any 
possibility  of  metal  increasing  the  capacity. 

Two-wire  Aerials. 


Lengths. 


0J 

o. 

V 
N 

u 

be 

"C 

3 

3 

6 

>, 

o 

u 

O 

o. 

-a 

55 

H 

W 

X 

> 

H 

O 

a 
*—* 

1 

T 

92 

130 

50 

115 

0.00075 

22,000 

232 

2 

T 

110 

151 

85 

160 

0.00090 

26,363 

290 

3 

T 

90 

210 

50 

155 

0.00092 

29,860 

312 

4 

T 

91 

208 

64 

168 

0.00096 

30,975 

325 

5 

L 

86 

216 

65 

281 

0.00101 

34,217 

350 

6 

L 

135 

238 

80 

318 

0.00095 

61,434 

455 

7 

T 

100 

240 

80 

200 

0.00140 

30,603 

390 

Four-wire  Aerials. 

8 

L 

68 

127 

90 

217 

0.00082 

49,621 

380 

9 

T 

ISO 

250 

90 

215 

0.00096 

53,210 

426 

10 

L 

70 

90 

90 

180 

0.00099 

23,600 

295 

11 

L 

125 

112 

75 

187 

0.00105 

41,932 

395 

12 

T 

128 

178 

100 

189 

0.00108 

34,215 

362 

13 

L 

90' 

100 

60 

160 

0.00110 

30,100 

340 

14 

L 

80 

120 

50 

170 

0.00115 

20,188 

287 

15 

T 

110 

170 

70 

155 

0,00115 

28,333 

340 

16 

T 

100 

225 

70 

182 

0.00115 

28,333 

340 

17 

T 

115 

170 

88 

173 

0.00116 

22,184 

320 

18 

L 

112 

220 

105 

325 

0.00130 

30,854 

380 

19 

L 

100 

120 

80 

200 

0.00135 

30,784 

384 

20 

T 

100 

260 

58 

188 

0.00136 

23,933 

340 

21 

L 

100 

150 

50 

200 

0.00140 

26,952 

366 

22 

L 

105 

204 

64 

268 

0.00145 

28,038 

380 

Six-ivire  A  erials. 

23 

L 

55 

125 

50 

175 

0.00085 

17,532 

230 

24 

L 

SO 

98 

50 

148 

0.00100 

33,246 

345 

25 

T 

135 

150 

90 

165 

0.00102 

25,690 

305 

26 

L 

125 

155 

85 

240 

0.00109 

36,272 

376 

27 

T 

96 

200 

85 

185 

0.00118 

21,192 

298 

28 

L 

105 

270 

70 

340 

0.00120 

55,902 

488 

29 

L 

94 

138 

50 

188 

0.00120 

30,085 

358 

30 

L 

98 

104 

90 

194 

0.00120 

20,428 

295 

31 

L 

125 

225 

80 

305 

0.00124 

46,615 

453 

32 

L 

115 

141 

84 

225 

0.00125 

30,335 

367 

33 

T 

60 

165 

35 

118 

0.00126 

20,134 

300 

34 

L 

95 

150 

70 

220 

0.00128 

30,946 

375 

35 

L 

115 

190 

95 

285 

0.00140 

32,200 

400 

36 

L 

100 

150 

60 

210 

0.00145 

38,451 

445 

37 

L 

120 

200 

70 

270 

0.00150 

34,272 

424 

38 

L 

145 

225 

100 

325 

0.00180 

27,343 

418 

39 

L 

98 

200 

60 

260 

0.00240 

21,200 

42.5 

Ten-wire  Aerial. 

40 

L 

50 

80 

30 

110 

0.00068 

16,639 

200 

L  = 

mean  standard 

inverted 

*T". 

A  DUSTPROOF  COVER  FOR  RADIO 
SETS. 

Having  an  open  desk  on  which  my  radio 
set  was  mounted,  and  being  greatly  troubled 
with  dust,  I  hit  upon  the  following  simple 
but  efficient  method  of  protecting  it  from 
dust.  A  shade  roller,  three  teet  long  in 
my  case  was  mounted  on  the  wall  about  six 
inches  above  the  desk.  A  cloth  three  feet 
wide  and  long  enough  to  cover  the  entire 
set  when  fully  extended  was  nailed  to  the 
shade  roller.  It  operates  as  follows :  When 
ready  to  use  set,  take  hold  of  cloth  and  pull 
away  from  the  roller  and  then  let  go.  The 
cloth  will  wind  itself  about  the  roller.  An 
ordinary  shade  will  do,  but  I  use  a  cloth 
because  it  presents  a  neater  appearance 
and  is  besides  more  flexible  than  the  ordi- 


A  Convenient  Way  In  Which  to  Protect  Your 
Apparatus    Table    From    Dust,    Utilizing  a 
Common  Window  Shade. 


MAKING  THE  BUZZER 
"HY-TONE" 

The  great  trouble  with  ordinary  buzzers 
used  for  detector  tests,  is  that  they  do  not 
emit  a  high  tone.  I  found  that  if  tightly 
folded  pieces  of  paper  were  placed  between 
the  magnet  and  armature  and  between  the 
armature  and  spring  that  carries  the  con- 
tact, the  tone  was  thereby  raised.  The 
best  thickness  of  the  paper  must  be  found 


Put  Paper  Here 


Any   Buzzer  Can   Be   Made  to  Give  a  High 
Tone  By   Placing   Paper  on   Either  Side  of 
the  Armature,  As  Shown. 

by  experiment.  Also,  the  contact  screw  must 
be  regulated  to  get  the  highest  tone.  Rubber 
bands  may  also  be  used.  These  are  snapt 
around  the  buzzer  in  such  a  way  as  to 
pass  thru  the  same  points  as  occupied  by 
the  paper. 

Contributed  by  E.  D.  PAPKEE. 


A  LAMP  "KICKBACK  PREVENTER." 

Two  lamps  are  connected  across  the  line, 
the  wire  between  the  lamps  being  grounded 
thru  the  third  lamp.     With  low  powers 


A  Kick-Back  Preventer  Made  From  Lamps 
Properly  Connected. 

there  will  be  little  danger  of  the  lamps  be- 
ing burned  out,  and  in  the  case  of  higher 
powers,  two  lamps  may  be  connected  in 
parallel  in  place  of  only  one  lamp.  Car- 
bon lamps  are  capable  of  carrying  heavy 
overloads  and  are  good  for  the  purpose. 
Contributed  by  THOS.  W.  BENSON. 


392 


THE  ELECTRICAL  EXPERIMENTER 


October,  1917 


A  Key  That  Will  Handle   1  K.W.  for  $1.00 


Following  is  a  description  of  a  wireless 
key  that  is  easily  made.  With  a  wooden 
base  it  costs  about  $1.00. 

The  lever,  shown  in  detail  in  Fig.  1,  is 
made  ol  a  %  inch  brass  slider  rod  about 


* 

 ;  t?  -  » 

/^~^\           fs-32  tap 

1  o 

Q  1 

t 

"  !w  *  

 /"- 


GZ 


7* 


t>ear//?tp  rode        so/aerecf  /'o  o/ace 


F/gl  -A- 


-ft* 


Br-  iOt 


-/I'- 
ve 


o 


piece  or  stretching  it,  until  it  is  the  right 
length,  thus  eliminating  the  thumb  nut  "F." 

The  binding  posts  G,  G,  the  thumb  nuts 
F,  F,  and  the  key  knob  I,  may  be  purchased 
from  any  electrical  supply  house  for  about 
6  cents  each. 

The  base  may  be 
made  of  wood,  fiber, 
hard  rubber  or  mar- 
ble. The  latter  im- 
proves the  looks  of 
the  key  considerably, 
but  it  comes  rather 
high  and  does  not  im- 
prove the  working  of 
the  key.  Nickel  plat- 
ing improves  the  ap- 
pearance also.  This 
key  will  take  care  of 
a  1  K.W.  set,  and  if 
carefully  made  will 
equal  a  $6.50  key. 

Contributed  by 
ALBERT  PARDEE. 


r  o- 

Si/ver      "s-32fap  \    8  \ 

'-  "deep  \  \ZZ  !  !  ttTf 


o 


#isp/dno  w/re 


-c- 


-c- 


2f- 


ft?  2 


O 


© 


Details  for  Making  a  First-Class  Radio  Key 
mers  Up  to  1    K.  W.  Cap 

7  inches  long,  bent  as  in  the  drawing.  This 
can  be  done  by  placing  it  in  a  vise  and  care- 
fully tapping  it  with  a  hammer.  The  bear- 
ing rod  (Fig.  2-c)  is  made  of  a  short  piece 
of  5/32  inch  brass  or  steel  rod.  This  is 
forced  thru  a  hole  in  the  lever  \y%  inches 
from  the  end.  A  little  solder  will  hold  this 
in  place  or  it  may  be  pinned  in  position. 
The  bearing  posts  are  of  l/z  inch  square 
brass  rod,  see  Fig.  2-b.  The  contacts  D— 
D+,  Fig.  2,  consist  of  two  pennies  and  two 
dimes  soldered  together.  The  upper  con- 
tact D —  is  then  soldered  to  the  lever.  Fig 
1.  The  lower  contact  is  then  soldered  to  a 
short  piece  of  copper  or  brass  bar  with 
a  binding  post  mounted  on  the  end.  Bind- 
ing post  G,  Fig.  4,  may  be  connected  to  the 
lever  in  numerous  ways. 

A  well-known  wireless  key  makes  use  of 
a  bronze  spring  pressing  up  against  the  lev- 
er. Another  way  is  to  connect  to  the  bear- 
ing post.    The  tension  spring  "E"  requires 


The  "What  to  do  with 
your  Radio  Set"  Contest 
Concluded 

When  the  Navy  De- 
partment declared  all 
radio  stations  closed,  it 
seemed  as  if  I  would 
have  to  pack  my  instru- 
ments away  for  about  six 
months  or  more,  as  there 
seemed  to  be  no  further 
use  for  them. 

However,  I  decided  to 
use  my  instruments  in 
some  other  way  than 
ascribed  for  them  in  their 
original  use.  Finally  I 
evolved  the  idea  of 
building  a  very  sensitive 
microphone. 

The  following  instru- 
ments are  used:  A  wire- 
less telephone  transmitter 
(or  an  ordinary  telephone 
transmitter),  an  Audion 
amplifier  set  and  phones.  The  wire  from  the  aerial 
is  used  to  connect  the  different  instruments.  Where 
one  wire  crosses  another,  the  insulators  can  be 
used  to  insulate  them.  If  this  set  is  to  be  put  up 
between  two  buildings,  a  return  wire  can  be  used 
bv  the  ground  usually  used  in  wireless.  — JACOB 
F'EIGENBAUM. 


Suitable  for  Transtot 
acity. 


Radio  Instruments  Useful  in  Electro-Chemistry 

Any  up-to-date  wireless  outfit  may  be  used  in 
the  study  of  "electro-chemistry."  The  amateur 
can  make  use  of  nearly  all  his  instruments.  The 
transformer  and  spark  gap  will  make  a  fine  little 
electric  furnace  or  open  arc.  Electrolysis,  electro- 
plating, and  electrotyping  are  easy.  Delicate  in- 
dicators and  variable  instruments  will  be  of  use 
in  electromotive  force  tests.  The  effects  of  mag- 
netism and  various  waves  on  chemical  actions  is 
interesting.  Battery  jars  and  electrodes  come  in 
handy.  The  resourceful  American  amateur  would 
need  only  glass-ware,  some  common  chemicals, 
and  a  text-book,  to  make  a  complete  laboratory. 
The  Experimenter  might  take  the  place  of  the 
text-book.  I  have  made  a  good  chemical  labora- 
tory of  my  wireless  room,  and  am  teaching  some 
grammar  school  boys  the  mysteries  of  chemistry. 
Electro-chemistry  is  as  instructive  and  interesting 
as  wireless  itself,  and  I  recommend  it  to  all  other 
amateurs.  —  J.  FRANK- 
LIN STYER. 


View  of  Assembled   Radio  Transmitting  Key. 


no  explanation,  except  that  it  may  be  made 
of  brass  spring  wire  instead  of  piano  wire. 
This  spring  may  be  adjusted  before  the  final 
assembling  of  the  key  by  cutting  off  a  small 


Miscellaneous  Experi- 
ments   for    the  "Radio- 
Bug" 

Imagine  yourself  to  be 
an  amateur  who  has  been 
presented  with  an  effi- 
cient sending  and  receiv- 
ing outfit;  time — Xmas. 
Time  flies  as  you  perse- 
vere over  the  code.  Feb. 
3,  1917,  U.  S.  breaks  re- 
lations with  Germany. 
You  are  able  to  hear 
NAA  give  out  reports 
and  gossip  over  the  war. 
declares  war  on  the  German 
April  7,  8,  9,  Radio  in- 
This  happens 


April  6,  1917,  U.  S. 
Imperial  Government, 
spectors  are  around  sealing  stations 
just  when  you  were  on  the  road  to  Radio  fame 
Wouldn't  it  jar  you? 


Cheer  up  I  Perhaps  this  will  help  you.  These 
ideas  of  mine  enable  the  "Radio-Bug"  to  use  his 
apparatus  in  war  time  without  evading  the  Federal 
law. 

The  apparatus  used  is  as  follows: 

Key,  batteries,  coil  or  transformer,  gap,  con- 
denser and  helix. 

Variable  or  fixt  condenser,  loose  coupler,  de- 
tector, 'phones,  and  buzzer,  perhaps  a  tuning  coil 
and  potentiometer. 

Idea  No.  1  enables  you  to  learn  the  code  or 
gives  you  practise  so  that  you  won't  get  out  of 
trim.  Uncover  that  soap  box  and  get  out  a  key, 
some  batteries,  a  buzzer,  'phones  and  detector, 
and  the  tuning  coil  or  potentiometer.  Connect  up 
according  to  diagram  1.  The  tuning  coil  or 
potentiometer  act  as  rheostats  and  increase  or 
decrease  the  pitch  of  the  buzzer.  The  condensers 
absorb  the  spark  usually  present  at  the  contact 
point  of  the  buzzer.  This  is  a  modified  buzzer 
test.  A  two  station  buzzer  line  has  been  in- 
stalled in  our  high  school  and  we  certainly  have 
fun.  Here,  a  key,  batteries,  buzzer  and  'phones 
are  used.     (Fig.  2.) 

High  frequency  experiments  may  be  tried  and 
currents  obtained  by  using  a  transformer  or  spark 
coil,  batteries,  gap  and  helix.  The  transformer 
takes  the  part  of  the  Tesla  coil  or  Oudin  resonator. 
Look  up  your  old  E.  E.'s  for  H.  F.  experiments. 
Then  get  to  work,  persevere  and  enjoy  yourself. — 
GEO.  KRUEGER. 


A  Simple  Buzzer  Set  for  Practising  the  Code. 


— u  JH  •  mm 

■1  IlJp^ 

~    ftp-?  0 

An  Efficient  Buzzer  Telegraph  System  Good 
for  Several  Miles. 


Cond 


Fig.  3.    Old  Tuning  Coils  or  Loose  Couplers 
Can    Be    Used    As    High-Frequency  Oudin 
Resonators. 


piiiiiiliill  iiii'iiiiiiMiiiiiiinii  iiiiiiiiiMiiiiiiiiiiiiiiii  iiiiiiiiiiiiiiiiiiiiiiiuniiiiiiiiuiuiiiiiiiiiiii| 

|     RADIO    WRITERS  —  ATTENTION!!!  | 

Can  you  write  radio  articles  dealing  g 

g     with  the  practical  problems  of  wireless  g 

g      operating?      We    can    use    some    good  g 

g     papers  on  such  subjects  as  "the  tuning  g 

g      of  radio  transmitters";  "the  use  of  the  g 

g      wave   meter,   including   its   application  §= 

g     to     measuring     the     frequency,  _  wave  | 

g      length  and  decrement";   "operation  of  g 

g      commercial  transmitting  and  receiving  g 

g      sets";    "the   operation   of  army   trunk  g 

B      sets";    "improved    ways    of    receiving  g 

=     undamped    wave    signals,"    also    new  g 

g      ideas  and  short-cuts  for  learning  the  g 

g      codes.     We  pay  well   for   all   articles  g 

H     accepted.     Help  yourself,  your  maga-  g 

g      zine  and  your  country.  = 

iiiiiuiimuiiiiiiiiiiiiiiiiiiiiiiiiuiiiiiiiiiiiiuiiiiiiiiiiii  iiliiiiiiiiiiiiiiiioiiiiiiiiiiiiiiiiiiiiiiiiuiiiiiiiiiiiiiif 


October,  1917 


THE  ELECTRICAL  EXPERIMENTER 


393 


A  Simplified  Variable  Condenser 


^LTHOUGH    there  are  a  great  many 
/\      forms  of  variable  condensers  on  the 
/-%    market  today,  there  are  few  types 
A.  JL  which  can  be  readily  constructed 
by  the  average  experimenter,  which 
will  approach  the  compactness,  and  good 
appearance  embodied  in  many  stock  articles 
of  this  nature. 

A  condenser  constructed  on  the  general 
lines  of  the  one  described  herein  should 
comply  with  the  above  requirements,  and 
as  can  be  seen  from  the  sketches  will  re- 
quire but  few  materials  and  little  work  for 
its  completion. 

As  various  capacities  will  be  desired  by 
the  different  amateurs  who  may  decide  to 
make  this  instrument,  no  definite  dimen- 
sions will  be  specified  in  the  following  notes, 
except  to  show  the  general  relation,  in  re- 
gard to  size  between  the  different  parts 
which  enter  into  the  construction. 

Very  few  parts  are  necessary  for  the 
work  in  hand,  the  complete  list  of  materials 
is  as  advised  at  this  point.  1  round  tubular 
fiber  or  composition  case.  1  round  top,  of 
metal,  fiber,  or  hard  rubber,  etc.  A  small 
quantity  of  lead.  A  few  feet  of  thin  brass 
or  copper  ribbon,  about  one  inch  wide,  pre- 
ferably of  soft  metal.  Several  pieces  of 
paper  tape,  about  three-fourths  of  an  inch 
wide,  by  about  one  sixty-fourth  thick.  2 
short  lengths  of  1  inch  half  round  fiber. 
Brass  screws,  about  one-quarter  inch  long, 
two  small  brass  screw-eyes,  2  binding 
posts,  a  short  round  brass  rod  and  small 
composition  knob,  complete  the  list  with 
the  exception  of  a  short  length  of  flexible 
copper  ribbon. 

In  order  to  construct  the  condenser  it 
is  necessary  to  cut  the  brass  or  copper  rib- 
bon into  two  equal  lengths,  each  one  inch 
wide,  and  with  a  few  of  the  small  brass 
screws  mentioned,  fix  one  end  of  each 
piece  to  the  flat  surfaces  of  the  half  round 
fiber,  one  piece  of  brass  to  one  of  fiber. 
This  should  be  done  in  such  a  manner  that 
the  end  of  each  brass  strip  comes  to 
within  about  l/8th  inch  of  the  center  of  the 
fiber,  on  the  flat  surface,  both  brass  strips 
also  being  positioned  near  the  center  of 
the  fiber,  in  regard  to  the  distance  from 
each  end. 

The  two  flat  surfaces  of  the  fiber  are 
now  fitted  together  in  such  a  manner  that 
the  two  pieces  form  one  round  rod,  with 
a  brass  ribbon  apparently  passing  thru  the 
center.  One  of  the  pieces  of  brass  should 
now  be  wound  part  way  around  the  rod, 
till  it  comes  into  contact  with  the  other 
piece. 

When  the  above  steps  have  been  taken, 


Fig.  1.  Showing  Detail  of  Moving  Spiral 
Plate  Member  of  Variable  Condenser;  the 
Brass  Ribbon  Spiral  Is  Held  by  Molded  Lad. 

the  fiber  rods  should  be  slid  along  on  each 
other,  so  that  if  the  metal  ribbon  is  wound 
around  the  rods,  the  pieces  will  overlap  at 


By  R.  U.  CLARK,  3rd 

each  end  1  /4th  of  an  inch,  thus  forming  a 
winding  1-1/2  inches  wide.  Before  the 
winding  is  commenced  however,  two  pieces 
of  paper  tape  should  be  placed  between  the 
brass  strips,  and  two  additional  pieces  made 
fast  to  the  outside  surface  of  the  second 
metal  ribbon,  in  such  a  position  that  when 
the  several  layers  of  metal  and 
paper  have  been  wound  into  a 
tight  coil,  there  will  be  an 
empty  annular  space  }4th  of  an 
inch  deep  between  the  brass 
strips  at  each  end  of  the  coil, 
the  remaining  34ths  inch  near 
the  center  being  filled  with  the 
paper  tape,  as  shown  in  Fig.  1. 

In  order  to  wind  the  paper 
and  metal  in  the  manner  speci- 
fied, it  will  first  be  necessary 
to  clamp  both  ends  of  the  fiber 
together.  After  the  coil  has 
been  completely  wound,  it 
should  be  bound  with  paper 
tape,  until  the  outside  diameter 
of  the  paper  ring  thus  formed 
is  equal  to  the  inside  diameter 
of  the  tubular  condenser  case. 
Both  ends  of  the  fiber  can  now 
be  sawed  off  flush  with  each 
other,  one  end  being  sawed  off 
about  ^th  of  an  inch  from 
the  end  of  the  coil.  The  other 
end  should  extend  about  %ths 
inch  beyond  the  end  of  the 
coil ;  see  Fig.  1. 

The  clamps  can  now  be  re- 
moved from  the  fiber  ends, 
and  the  condenser  case  split 
over  the  coil,  which  should  be 
pushed  into  position,  so  that 
the  short  end  of  the  fiber 
comes  to  within  about  ^th 
inch  of  the  top  end  of  the  case. 
Molten  lead  should  now  be 
poured  in  to  fill  the  remaining 
space  to  the  top  of  the  case, 
after  a  short  strip  of  very 
thin  copper  ribbon,  about  one- 
fourth  inch  wide,  has  been  in- 
serted in  the  space  betwen  the  pieces  of 
fiber.  This  piece  should  be  bent  over  once 
at  the  lower  end  before  being  inserted,  so 
that  when  the  lead  has  been  poured,  the 
copper  ribbon  cannot  be  withdrawn. 

The  condenser  case  should  now  be  moved 
along  over  the  coil  of  metal  and  paper  tape, 
until  the  other  exposed  ends  of  the  fiber 
pieces  extend  beyond  the  case  about  l/8th 
of  an  inch.  This  should  cause  the  upper 
lead  casting  to  move  down  about  1  inch. 

Several  layers  of  paper  tape  should  next 
be  wound  around  the  lower  end  of  the  case 
to  form  a  mould  for  the  lead  base  which 
is  integral  with  the  metal  portion  which 
holds  the  lower  set  of  spiral  plates  as 
shown  in  Fig.  2. 

The  various  parts  are  now  removed  from 
the  case,  and  the  two  sets  of  spiral  plates 
are  carefully  pulled  apart,  the  paper  tape 
being  removed  at  the  same  time.  If  these 
parts  are  now  placed  in  their  original  posi- 
tions in  the  case  they  should  slide  freely 
in  and  out  of  each  other.  In  the  event  of 
the  friction  being  too  great  to  allow  free 
movement,  the  lead  and  fiber  on  the  mov- 
able portion  of  the  plates  can  be  filed  down 
a  little  to  permit  unobstructed  movement. 

The  top  piece  for  the  condenser  should 
now  be  slotted  to  allow  the  copper  ribbon 
to  pass  thru,  the  latter  being  then  attached 
to  the  round  brass  rod,  mentioned  in  the 
list  of  materials. 

The  top  is  next  fastened  to  the  case  by- 
means  of  a  brass  screw  eye  on  one  side, 
and  a  small  screw  binding  post  on  the  other. 
The  brass  rod  mentioned  above  is  then 


put  into  place,  being  slipt  thru  the  screw 
eye  on  the  right  hand  side,  as  in  Fig.  2, 
and  using  for  its  other  support  a  second 
screw  eye  held  in  the  binding  post  as  shown. 

A  composition  or  rubber  knob  placed  on 
one  end  of  the  brass  rod,  and  a  small  bind- 
ing post  fitted  to  the  lead  base,  complete 


Fig.  2.  Unique  Variable  Condenser,  Suitable  for  Radio 
and  Other  Circuits.  The  Movable  and  Stationary  Plates 
(Spirals  of  Brass  Ribbon)  Are  Both  Held  by  Molded 
Lead  at  Top  and  Bottom  of  the  Condenser,  As  Shown. 
Oil  Dielectric  Can  Be  Used,  Giving  As  High  As  Five 
Times  the  Capacity   With  Air. 


the  construction  of  the  condenser. 

In  operation  the  plates  are  separated  by 
turning  the  knob,  the  weight  of  the  movable 
plates  causing  them  to  sink  into  place  be- 
tween the  fixt  plates,  when  the  knob  is 
turned  in  the  proper  direction,  and  the  fric- 
tion on  the  rod.  brought  about  by  com- 
pressing the  bearings,  prevents  the  plates 
from  moving  on  their  own  account. 

This  condenser  can  be  shellacked  around 
the  bottom  joint  and  filled  with  oil  to  in- 
crease its  capacity,  and  in  this  maner  a  very 
compact  and  simple  instrument  will  be  ob- 
tained which  will  give  excellent  results. 


MAKES  RESERVATION  IN  "ENGI- 
NEERS" BY  WIRELESS. 

Fearing  that  he  would  arrive  too  late  to 
enlist  in  the  Eighteenth  engineers,  railway, 
United  States  Army,  Warren  A.  Taylor,  a 
railroad  man  of  Cordova,  Alaska,  recently 
wirelessed  Col.  J.  B.  Cavanaugh,  com- 
mander of  the  regiment,  to  hold  a  place 
for  him.  Taylor  arrived  in  time  to  enlist 
at  the  Eighteenth's  emergency  recruiting 
office. 

For  the  last  seven  years  Taylor  has  been 
an  engine  man  on  the  Cooper  River  North- 
western. On  learning  that  the  Uniteid 
States  was  organizing  nine  railway  regi- 
ments to  send  to  France,  he  began  prepara- 
tions for  the  trip  to  Seattle  to  enlist.  He 
was  delayed,  but  decided  to  take  a  chance 
on  getting  into  the  regiment  on  the  eve 
of  its  departure  for  Europe.  When  the 
steamship  Alaska  was  two  days  out  he  sent 
the  wireless  asking  for  a  "reservation." 


394 


THE  ELECTRICAL  EXPERIMENTER 


October,  1917 


PORCELAIN  KNOBS  AS  ANTENNA 
INSULATORS. 

The  drawing  is  that  of  an  aerial  which 
is  insulated  with  material  which  is  com- 
monly found  around  any  work  shop.  By 
looking  at.  the  illustration  you  will  see  that 
it  comprises  merely  two  porcelain  knob 


Clever  Way  of  Utilizing  Porcelain  Knobs  in 
Supporting   Antenna   or  Other   Line  Spans. 
The  Knobs  Are  Bolted  to  the  Spar  in  Pairs 
as  Shown. 


insulators,  fastened  on  the  spreader  by  a 
bolt  of  sufficient  length.  This  is  a  cheap 
but  neat  insulator  and  will  work  very  nice- 
ly for  receiving  or  small  sending  stations. 
Contributed  by 

BENJAMIN  L.  TEAM. 


AN   ARCLESS  MAGNETIC  RADIO- 
RELAY. 

To  make  this  key  first  take  an  electro- 
magnet that  has  a  tapt  hole  in  one  end  and 
rewind  with  wire  that  is  heavy  enough  to 
stand  full  load  current  of  the  transformer, 
grounding  one  end  firmly  to  the  core.  (Al- 
low 800  circular  mils  per  ampere  for  cross- 
section  of  wire.)  Then  rivet  a  piece  of 
silver  on  the  end  of  the  core  opposite  the 
hole  and  mount  on  a  suitable  base  by  a 
bracket  B,  formed  by  bending  a  piece  of 
heavy  sheet  iron  into  the  shape  of  an  L, 
but  before  bending  drill  three  holes  in 
it,  two  to  hold  it  to  the  base  and  one  to  ac- 
commodate a  screw  to  support  the  coil,  as 
shown.  Then  make  two  more  brackets,  B, 
and  B2,  similar  to  B,  of  heavy  sheet  brass. 
To  B1  (see  drawing)  is  soldered  the  arma- 
ture, which  is  made  of  a  piece  of  thin  sheet 
steel.  On  to  this  is  soldered  the  other  silver 
contact  which  corresponds  to  the  one  on  the 
end  of  the  coil. 

The  third  bracket  may  be  made  exactly 
like  B,  and  will  be  used  to  hold  the  helical 
spring  and   its  means   of   adjustment,  as 


Due  to  the  Fact  that  the  Alternating  Cur- 
rent from  the  Transformer  Line  Flows  Thru 
the  Key  Magnet  Coil,  the  Final  "Break"  of 
the  Circuit  Occurs  at  the  Zero  Part  of  the 
Cycle. 

shown.  The  other  end  of  the  spring  is 
soldered  on  to  the  armature,  as  soon. 
Three  binding  posts  should  be  provided  and 


connected,  as  indicated  by  dotted  lines.  The 
external  connections  are  also  shown. 

Now,  if  the  key  is  deprest,  current  will 
flow  thru  the  key,  transformer  and  relay 
coil,  the  current  thru  the  latter  causing  it 
to  attract  its  armature,  which  will  alter- 
nately open  and  close  the  silver  contacts, 
which  are  shunted  across  the  key,  due  to 
the  alternating  character  of  the  current 
flowing  in  it,  the  armature  flying  back  when 
current  approaches  zero,  to  be  attracted 
again  when  it  increases  afain,  etc. 

Now,  if  the  key  is  releast  when  the  value 
of  the  current  is  great  enough  at  that  in- 
stance to  attract  the  relay  armature,  the 
circuit  will  not  be  opened  by  the  key,  there- 
fore no  spark  occurs  at  its  contacts ;  nor 
will  the  circuit  be  opened  until  the  value 
of  the  alternating  current  has  reached  a 
value  so  low  that  it  can  no  longer  hold  the 
armature,  which  then  flies  open,  opening  the 
circuit  when  there  is  very  little  current  flow- 
ing, which  means  practically  no  spark  at 
the  relay  contacts. 

The  difference  in  time  between  the  open- 
ing of  the  key  is  so  short  that  it  is  unno- 
ticeable,  being  less  than  1-1/120  part  of  a 
second  when  60  cycle  current  is  used. 

Contributed  by       LOREN  AN  SLOW. 


MAKING  SWITCHBOARD  AND  IN- 
STRUMENT BASES  OF  SLATE. 

Owing  to  the  high  cost  of  hard  rubber, 
vulcanized  fiber  and  other  suitable  ma- 
terials, many  amateurs  use  wood,  with  the 
result  that  the  instruments  are  not  efficient, 
due  to  the  fact  thr.t  wood  easily  absorbs 
moisture.  I  would  suggest  that  greater  use 
be  made  of  ordinary  roofing  slate  instead 
of  wood,  as  it  can  be  worked  almost  as 
easily  as  the  latter. 

The  slate  is  cheap  and  can  be  easily  pro- 
cured. It  is  cut  to  the  desired  size  with  an 
ordinary  wood  saw  (lubricate  with  water), 
preferably  one  having  about  ten  teeth  to 
the  inch.  A  hack  saw  will  make  a  very 
clean  cut  but  will  cut  very  slowly.  I  would 
suggest  using  a  cheap  saw  such  as  can  be 
procured  in  a  five  and  ten  cent  store,  as 
a  good  saw  would  be  ruined,  or  would,  to 
say  the  least,  need  "some"  re-filing.  After 
the  slate  has  been  cut  the  edges  are 
smoothed  and  beveled  with  a  file  and  the 
whole  well  rubbed  down  with  fine  sand- 
paper and  a  block.  If  the  slate  is  not 
thick  enough,  two  pieces  may  be  cemented 
together  with  thick  shellac  or  may  be  held 
together  by  means  of  the  screws  holding 
the  instruments.  Hoks  for  binding  posts, 
switches  or  instruments  can  be  drilled 
easily  with  a  diamond  point  or  twist  drill. 
Before  fastening  on  the  instruments  the 
slate  is  again  well  rubbed  down  with  fine 
sand  paper  or  emery  cloth  and  given  a  coat 
of  varnish  or  shellac.  The  finished  base 
will  look  very  much  like  hard  rubber. 
Many  slate  switchboards  are  simply  rubbed 
up  thoroly  with  linseed  oil.  Others  are 
given  a  coat  of  some  good  insulating  var- 
nish such  as  black  armalac. 

Contributed  by  JOSEPH  BACKERT. 


SECRET   "WIRELESS"   IS  FOUND 
ON  APPAM. 

Federal  authorities  recently  found  a  se- 
cret wireless  plant  aboard  the  interned 
steamship  Appam,  which  was  taken  pos- 
session of  by  United  States  Marshal  Saun- 
ders at  Newport  News,  soon  after  the 
severance  of  relations  with  Germany. 

A  fine  wire  was  found  strung  beneath 
the  pipe  leading  to  the  whistle  on  the 
smokestack  of  the  Appam  and  extending 
above  it  as  do  the  antennae  of  wireless 
plants.  The  wire  led  to  the  interior  of 
the  vessel  where  the  lighting  plant  dynamos 
were  kept  running.  When  the  Appam  was 
first  brought  into  port,  the  dynamo  in  the 


A  SIMPLE  POTENTIOMETER 
CONTROL. 

The  carbon  ring  used  in  making  this 
potentiometer  may  be  sawed  off  the  bot- 
tom of  an  old  wet  cell  carbon  cylinder. 
It  should  be  about  y%"  or  l/2"  in  thick- 


An  Efficient  and  Finely  Adjustable  Potentio- 
meter Constructed  from  a  Ring  of  Battery 
Carbon  and  a  Switch  Blade. 


ness.  After  filing  and  sand-papering  the 
top  smooth,  it  then  should  be  glued 
to  a  base  with  a  wire  connecting  to  one 
binding  post.  In  the  center  of  the  carbon 
circle  so  formed,  mount  a  hard  rubber 
knob  and  switch  lever  so  as  to  make  con- 
tact with  the  ring. 

This  potentiometer  is  very  easily  and 
cheaply  constructed.  A  large  number  of 
them  may  be  made  from  one  carbon 
cylinder.  They  will  prove  useful  in  con- 
trolling the  current  in  radio  and  electrical 
circuits. 

Contributed  by  BURT  CLARK. 

wireless  room  was  removed  by  the  Fed- 
eral authorities..  Later,  however,  Lieuten- 
ant Berg  ran  a  wire  to  the  wireless  ap- 
paratus from  the  dynamo  in  the  boiler 
room  of  the  steamship  and  connected  it  so 
that  he  could  either  send  or  receive  mes- 
sages. 

From  the  wireless  room  another  wire  led 
to  Lieutenant  Berg's  private  room  in  Nor- 
folk. Messages  were  flashed  to  him  in  the 
Morse  code  on  his  electric  light  bulb  by  the 
simple  process  used  in  flashing  messages 
between  battleships  at  sea. 


HOW  TO  IMPROVE  ROTARY 
SWITCHES. 

After  having  trouble  with  the  connec- 
tions to  the  moving  member  of  a  rotary 
switch  on  a  loose  coupler,  I  adopted  the 
following  scheme: 


\gl  Ml 

m 


fiii  \  \ 

|p\  Brass  plafe 
Nut  so/dered 


Effective    Arrangement    of    Rotary  Switch 
Blade   to    Ensure    Positive    Contact   at  All 
Times. 

In  figure  "A"  is  a  phosphor  bronze  spring, 
bent  as  shown,  so  as  to  bear  on  the  pointed 
end  of  the  threaded  rod  of  the  switch  knob. 
The  contact  is  kept  bright  by  the  constant 
turning  of  the  switch. 

Contributed  by        ASA  S.  KELLER. 


October.  1917 


THE  ELECTRICAL  EXPERIMENTER 


395 


m  C2N5TRUQT5R 


Making  An  Electric  Clock 

By  THOMAS  REED 


Part  II.— Wheels. 

I MEAN  clock-wheels,  not  the  ones  in 
your  head.  Clock  works  are  pretty 
hard  to  make  unless  you  have  a 
lathe,  but  you  can  fudge  up  some- 
thing that  will  do  out  of  the  works 
of  a  kitchen  clock.  I  mean  the  old-fa- 
shioned wooden-case  clock  with  the  peaked 


Phantom    View    of    the  Modified 

Adapted  to  Be  Driven  by  Electricity.    Fig.  7  Shows 
Detail  of  Steel  Burr  for  Milling  Ends  of  Arbors. 


top,  whose  works  are  simple  and  rugged. 
You  discard,  of  course,  the  power-wheel 
(spring  or  weight)  and  any  other  wheels 
which  occur  on  the  power-side  of  the  min- 
ute-hand arbor. 

If  you  were  going  to  use  a  pendulum 
of  the  same  short  length  as  the  kitchen 
clock,  you  would  have  pretty  plain  sail- 
ing; but  1  assume  you  want  a  seconds- 


the  old-fashioned  clocks  this  was  apt  to 
be  the  fact,  and  that  wheel  was  the  one 
just  preceding  the  'scape-wheel.  So  the 
thing  to  do  is  to  take  the  'scape-wheel  off 
its  arbor  and  put  it  in  place  of  the  gear 
on  the  preceding  arbor.  That  isn't  so  hard, 
but  you  can't  have  a  second-hand  on,  un- 
less you  want  one  running  backward.  If 
you  have  a  lot  of  old  clock- 
wheels,  perhaps  you  can  pick 
out  two  that  are  exactly  alike, 
and  transfer  the  motion  equal- 
ly but  in  opposite  directions 
from  your  minute-arbor  to 
your  old  'scape-wheel  arbor,  in 
which  case  it  will  run  right 
and  come  thru  fairly  symme- 
trically on  your  main  dial.  To 
extend  the  arbor  in  order  to 
carry  the  second-hand,  you  can 
buy  some  very,  very  small  brass 
tube  (it's  made,  I  assure  you) 
and  tuck  a  piece  of  it  over  the 
end  of  the  arbor,  reaming  the 
front  hole  out  to  correspond ; 
or  you  can  make  up  a  little 
tube  yourself  if  you're  careful. 
I  made  an  entire  new  arbor  by 
filing  while  rotating  in  the 
lathe. 

Also,  the  'scape-wheel  you 
use  must  have  30  teeth.  Per- 
haps it  seems  too  much  to  ex- 
pect of  an  old  clock  to  satisfy 
so  many  requirements,  but  lots 
of  them  do  have  30-tooth 
'scape-wheels.  Junk-stores  usu- 
ally have  several  of  these  old 
clocks  for  sale  cheap,  and 
you're  pretty  apt  to  meet  up 
with  one  that  passes  the  test. 
If  worse  comes  to  worst,  you 
can  use  an  odd  gear-reduction, 
and  make  up  an  odd-length 
pendulum,  experimentally,  to 
match  it. 

Now  about  the  escapement. 
A    plain    ratchet-and-pawl  is 
what  one  first  thinks  of,  with 
click   to   prevent   its  dragging 
but  that  isn't  satisfactory,  as 


Flo.  8 

Special  Tapered  Stud  to  Hold  Hand-drill  Chuck  In  Lathe 
The  Arbor  Burr,  Fig.  7,  Is  Then  Held  In  This  Chuck. 

pendulum  (see  Sept.  issue),  and  that  makes 
it  hard.  In  the  first  place,  the  works  must 
have  been  designed  so  that  one  of  the 
wheels  revolves  in  just  one  minute.  In 


an  extra 
backward ; 

occasionally  the  pawl  will  ride  over  a  tooth, 
or  fail  to  catch  it — you  can't  tell  why. 
Fig.  1  shows  a  reliable  construction,  which 
is  a  reversal  of  the  so-called  gravity  es- 
capement. When  the  pendulum  lifts  the 
lever  on  the  right,  the  one  on  the  left 
drops,  forcing  the  pallet  P  between  the 
teeth  A  and  B,  with  a  sliding  motion  into 
the  space  C,  and  moving  the 
wheel  J/2  tooth  ahead.  On  the 
return  swing,,  the  right-hand  pal- 
let P\  drops  between  teeth  D 
and  E,  but  can't  move  the  wheel 
until  the  left-hand  pallet  P  is 
lifted  an  instant  later;  then  pal- 
let P1  drops  into  space  F,  moving 
the  wheel  another  y2  tooth  in  the 
same  direction  as  before.  The 
pallets  have  to  be  adjusted  to 
each  other  to  work  coincidently,  but  you 
only  have  to  make  one  of  them  adjustable, 
of  course  (see  Fig.  2).  It  isn't  vitally  im- 
portant what  part  of  the  circumference  the 


pallets  meet.  The  pallets  are  made  of  steel, 
and  as  highly  polished  as  possible.  The 
size  varies  with  the  'scape-wheel  teeth ;  the 


Electrical  Experimenters  Take  Our  Advice, 
Build    a    Home-Made    Electric    Clock.  You 
Will  Always  Be  Proud  of  It. 

base  of  the  wedge  should  be  quite  a  bit 
wider  than  the  space  between  the  teeth. 

In  Fig.  1,  the  escapement  bars  are  hung 
from  arbors,  and  the  impulses  are  given 
by  the  little  weights — W,  W.  The  same 
result  could  probably  be  accomplisht  by 
mounting  the  escapement  bars  on  springs, 
which  would  be  an  easier  construction  for 
some. 

Recess  now  for  a  "wrinkle."  It's  about 
oiling  clocks.  Use  toilet  vaseline.  I  know 
all  the  old  clockmakers  will  howl  in  uni- 
son at  this,  for  they  say  use  the  "runniest" 


Handy  Jig  For  Matching  Up  Gears  and  De- 
termining   Their    Correct    Spacing  Between 
Arbor    Centers    Before    Drilling    the  Main 
Frame. 


396 


THE  ELECTRICAL  EXPERIMENTER 


October,  1917 


Front  plate 


Side  View  of  Complete  Electric  Clock  Movement,  lllus-  t]le  proper  reduction 
trating   Suspension   of  Pallet   Levers,   Escape   Wheel        i  i-  / 

and  Pendulum.  g°od    proportion  (i 


Weight 


oil  there  is ;  but  I've  tried  vaseline  and  I 
know.  Thin  oil  tends  to  run  out  of  the 
bearings  and  spread  on  the  plates.  My 
clock  was  deficient  in  depth  of  the  counter- 
sinkings,  which  are  supposed  to  hold  the 
oil  by  capillarity,  and  I  had  to  re-oil  it 
every  6  months  or  so ;  but  now,  with  a 
little  daub  of  vaseline  on  each  arbor-end 
and  on  the  pallets,  I  never  have  to  touch 
it.  I  added  a  little  grafite  scraped  from 
a  hard  lead-pencil,  but  really  I  don't  know 
whether  that  improved  it  or  not.  Vaseline 
stays  where  you  put  it. 
and  doesn't  gum.  I'd 
laugh  if  it  should  prove 
a  popular  lubricant  for 
clocks  on  my  recommen- 
dation. I  remember  I 
used  it  on  my  bicycle 
years  ago,  when  all  the 
wiseacres  said  it  was 
the  worst  thing  you 
could  do,  and  would 
bring  down  on  the  pa- 
tient tin  steed  some 
mysterious  calamity  re- 
sembling the  Curse  of 
Muldoon  in  direness. 
Everybody's  doing  it 
now. 

If  you  have  a  lathe 
with  a  self  -  centering 
chuck,  you'll  want  to 
make  your  own  works, 
so  I  give  you  the  detail 
drawings  of  mine  (Figs. 
3,  4,  5,  6).  As  to  the 
gears — you  buy  'em.  The 
various  gear  companies 
publish  nice  illustrated 
catalogs  from  which  you 
can  select  gears  and 
pinions  with  the  proper 
sizes  and  numbers  of 
teeth.  I  could  tell  you 
here  the  name  of  one 
good  Gear  Works,  but  I 
won't,  because  I  think 
they  ought  to  advertise 
in  "E.  E." !  It's  up  to 
the  Editor  to  go  get  'em.  By  the  "ads"  he 
already  has,  I  judge  he  has  some  irresistible 
method  of  pulling  'em  in,  so  I  shouldn't  be 
surprised  if  we  heard  a  peep  or  two  from 


that  quarter  shortly. 
(Voice  from  the  deep: 
In  1915-16  four  gear 
people  advertised  in  the 
"E.  E."  They  all  quit, 
because  "E.  E."  readers 
did  not  buy  any  gears,  it 
seems.  Moral:  "E.  E." 
readers  support  adver- 
tisers !  Editor.) 

Wrinkle  : — The  pinions, 
or  small  gears,  come  in 
rods,  which  you  have  to 
cut  up  and  drill  concen- 
trically; so  if  your  chuck 
has  three  jaws  you  can 
practically  only  use  a  6- 
toothed  pinion,  other- 
wise it  won't  center 
right.  If  you  are  adept 
in  lathe  work,  however, 
you  can  drill  any  pitch 
gear,  concentrically  by 
placing  a  piece  of  steel 
ur  brass  strip  around  it 
and  then  tightening  up 
the  chuck.  A  piece  of 
thin  sheet  lead  is  excel- 
lent, as  there  is  less 
chance  of  damaging  the 
teeth.  But  this  is  no 
obstacle,  as  you  can  ap- 
portion the  teeth  of  the 
larger  gears  to  obtain 
A 
60-6 

and  36-6)    is  shown  in 
the  drawings. 

Of  course  the  gears  referred 
to  are  not  the  broad-faced 
kind,  but  the  thin  clock-gears. 
The  Gear  Works  sell  them  and 
if  there's  any  choice,  get  the 
thinnest  and  tiniest  ones  you  can.  as  there's 
no  power  on  them.  You  can  also  buy  30- 
tooth  'scape-wheels  —  "star-wheels"  —  with 
the  teeth  radiating  from  the  centre  (Fig.  1) 
instead  of  inclined  like  those  of  mechanical 
clocks.    Just  as  good  either  way. 


o 

O 

/  A\ 

uscapemenh 

\  30  teeth  l 

Pallet  fcj 

J  Pallet 

f\ 

ll  1 

'  6A  »,' 

\\  ' 

/r  1 

i ' 

6 

Weight 


O 


Stud 


o 


Suspension 
spring 


O 


n3 


Here,  "Bugs,"  We  See  the  Arrangement  of 
the  Electric  Clock  Gear  Train.    It's  Simple  We 
Assure  You. 


One  thing  you  can't  buy,  tho,  and  that's 
the  hand-wheels — those  re-entering  gears 
which  reduce  the  minute  to  the  hour  speed. 
You'll  have  to  bone  them  from  some  ex- 


Details  of  Escapment  Mechanism  Showing  How  the  Pal- 
let's P  and  P1  Rotate  the  Star  Wheel,  As  the  Weighted 
Levers  Are  Moved  Alternately  by  the  Swinging  Pendulum 
Bar. 


isting  clock. 

About  reducing  the  ends  of  the  arbors 
to  the  size  of  the  bearing-holes,  you  can 
do  this  in  the  lathe  with  a  file  all  right, 
and  then,  after  polishing,  ream  out  your 
holes  to  fit.  The  holes  ought  to  be  drilled 
jSmall  and  reamed 
(broached)  anyway,  as  a 
plain  drill-hole  is  pretty 
rough.  A  little  young 
reamer  for  such  small 
holes  costs  only  10  cents 
or  so.  Any  watch  or  clock- 
maker  will  sell  you  one 
of  these  tapered  reamers 
— called  broaches.  If  you 
want  to  take  the  trouble, 
instead  of  filing  you  can 
make  yourself  a  small 
steel  "burr"  (Fig.  7) 
which  isn't  difficult,  and 
then  your  arbor-ends 
will  all  be  the  same  size, 
and  true.  Only  you  have 
to  hold  the  burr  in  a 
drill-chuck  set  in  the 
tail-stock.  Wrinkle :  I 
use  the  little  chuck  off 
of  my  hand-drill,  having 
made  for  it  a  tapered 
stub  with  the  proper 
thread  (Fig.  8).  It's 
the  handiest  thing  there 
is  about  the  house,  and 
if  I  lost  it  I'd  give  way 
to  despair  and  get  me  to 
a  nunnery  —  well,  you 
know  what  I  mean,  the 
other  kind. 

To    mill   your  clock- 
arbor,  you  hold  it  in  the 
head-stock    chuck,  and 
while  in  motion  run  the 
burr  up  on  one  end  at  a 
time,  till  the  distance  between  the  shoulders 
is  the  same  as  that  between  the  front  and 
back  plates — with  an  allowance  for  ease. 
(Continued  on  page  425) 


Pendu/um- 


S/of 


Piff  5 


o 


Rear  View  of  Clock  Plate.    The  Pal- 
let  Levers  Are   Moved  by  Pins  on 
Either  Side  of  Pendulum. 


October,  1917 


THE  ELECTRICAL  EXPERIMENTER 


397 


Building  a  Good  Carbon  Compression  Rheostat 


A  rheostat  that  will  serve  over  a  wide 
range  of  uses  may  be  made  from  a  number 
of  pieces  of  sheet  carbon.  Anyone  who  has 
tried  water  rheostats  knows  that  it  is  very 
difficult  for  these  rheostats  to  keep  a  con- 
stant resistance,  owing  to  the  fact  that  par- 
ticles of  the  electrodes  either  float  in  the 
electrolyte  or  settle  at  the  bottom  of  the 
container,  and  thus 
increase  the  conduc- 
tivity. The  longer 
they  are  used  the 
lower  their  resis- 
tance becomes,  and 
often  considerable 
damage  is  done  due 
to  this  fact.  Rheo- 
stats made  of  resis- 
tance wire,  besides 
being  rather  expen- 
sive, require  some 
time  and  trouble  in 
order  to  make  suit- 
able contacts  and  a 
more  or  less  elabo- 
rate contact  arm  to 
swing  over  them. 

A  carbon  rheostat 
is  cheap  and  easy  to 
make,  will  keep  a 
practically  constant 
resistance  and  is  not 
likely  to  burn  out 
when  overloaded. 
The  one  to  be  de- 
scribed has  a  range 
from  about  ^  to  a 
few  hundred  am- 
peres at  a  pressure 
of  V/2  volts,  tho  the 
details  of  construc- 
tion may  be  varied  to  suit  the  purpose  for 
which  it  is  to  be  used. 

The  materials  needed  are  a  piece  of  Y% 
sheet  carbon  12"  by  12",  2  brass  rods  3/16 
in  diameter  and  6^4"  long,  2  pieces  of  2 
by  2"  sheet  fiber,  about  a  foot  of  5/16 
fiber  tubing  (outside  diameter),  some  Yz 
sheet  steel  or  copper,  a  fiber  wheel  2"  in 
diameter  and  y%"  thick,  a  heavy  brass  screw 
(see  illustration),  some  washers,  4  nuts  and 
4    flat-headed    No.    10-32    brass  machine 
screws.    Two  pieces  of  2"  by  2"  brass,  J4" 
(iron  or  copper  *4  inch  thick  will  do)  thick 
will  also  be  needed. 


top  of  the  base.     A  slate  base  is  good. 

Lay  off  the  sheet  carbon  in  2  inch  squares, 
and  drill  holes  in  each  piece  as  indicated. 
After  the  holes  are  drilled,  the  squares 
should  be  cut  out,  making  36  of  them  in 
all.  This  may  be  done  by  carefully  cutting 
the  carbon  with  a  hack  saw,  or  a  sharp 
pointed  scriber  may  be  run  along  the  guide 


Plan  View  of  a  Compression  Type  Carbon  Plate  Rheostat  of  Many  Uses.     It  Will  Handle 
Currents  of  From  .5  Ampere  to  200  Arrrperes.    The  Resistance  Is  Lowered  by  Compressing 
the  Carbon  Plates  and  Vice  Versa. 


Dimensions  of  Carbon  Plate  Units,  Compression  Screw,  Etc. 
Rheostat  Illustrated  Above. 


Secure  a  suitable  baseboard  about  7"  by 
4"  by  ^2".  A  piece  of  marble,  slate  or  as- 
bestos board  will  be  excellent  but  any  hard 
wood  will  do.  For  high  amperage,  it  is 
advisable,  if  the  base  is  to  be  of  wood,  to 
fasten  some  heavy  asbestos  sheeting  to  the 


lines  a  few  times  and  the  carbon  will  then 
break  quite  easily. 

The  brass  rods  should  be  threaded  with 
a  No.  10-32  die  which  fits  them  exactly. 
The  two  brass  plates  which  are  thick 
must  have  holes  drilled  in  them  so  as  to 
permit  the  brass  rods  to  pass  thru  them. 
Holes  thru  their  ends  also  are  drilled  and 
tapt  to  facilitate  screwing  into  the  base. 
All  the  other  square  pieces,  whether  of  cop- 
per, fiber  or  carbon,  have  fi"  holes  drilled 
in  them  in  the  position  indicated.  • 

Securely  fasten  one  of  the  %"  brass 
plates  on  end,  to  the  base.  Slip  the  rods 
thru  it  and  fasten 
with  washers  and 
nuts.  Then  slip  a 
piece  of  fiber  tubing 
5y&"  long  on  to  each 
rod.  The  square 
pieces  are  then  slipt 
over  the  fiber  tubing 
and  rods  in  the  fol- 
lowing order:  First 
a  piece  of  fiber, 
then  a  piece  of  cop- 
per with  an  ear  on 
it,  then  the  36  car- 
bon plates,  then  the 
other  copper  plate 
with  the  ear  on  it, 
then  the  other  piece 
of  fiber,  then  the 
piece  of  sheet  iron. 
( See  assembly 
drawing.)  The 
fiber  tubing 
should  now  project 
%"  above  all  the 
plates  and  the  rods 
should  project  thru 
the  tubing.  Slip 
washers  on  the  rods,  then  put  on  the  last 
pieces  of  ¥4"  brass  plate.  This  last  piece 
has  a  J4"  hole  drilled  and  tapt  thru  its  cen- 
ter to  receive  the  heavy  brass  screw.  Now 
slip  another  washer  on  each  of  the  rods 
and  screw  down  with  nuts.    Then  secure- 


ly fasten  the  lA"  brass  plate  to  the  base. 

The  fiber  compression  wheel  is  fastened 
to  the  heavy  brass  screw  with  machine 
screws  which  are  countersunk  in  the  fiber. 
The  head  of  the  brass  screw  has  4  holes 
drilled  and  tapt  in  it  for  this  purpose.  The 
threads  are  No.  10-32. 

Binding  posts  are  fastened  to  the 
holes  of  the  projections  of  the  copper 
plates,  and  serve  as  the  terminals  of  the 
rheostat.  The  re- 
sistance of  the  rheo- 
stat decreases  the 
more  the  fiber  wheel 
is  screwed  down, 
and  vice  versa.  For 
smaller  loads  the 
rheostats  may  be 
made  more  sensitive 
by  using  more  car- 
bon plates.  Carbon 
rheostats  are  used 
for  many  purposes 
and  in  a  great  many 
places.  They  are 
used  by  standardiz- 
ing laboratories  such 
as  the  Governmental 
laboratories  and  in 
the  Universities. 
They  are  used  by 
testing  departments 
of  practically  a  1 1 
kinds  of  electrical 
supply  companies, 
whether  electric  rail- 
way or  electric  light- 
ing, and  provide  a 
simple  and  satisfac- 
tory method  of  regu- 
lating direct  current 
for  test  purposes, 
if  they  are  proper- 
rheostat  provides  as  in- 
statisfactorv  control 


ly  made.  This 
dicated  in  the  article 
for  currents  from  .5  to  a  few  hundred  am 
peres  at  battery  potential  of  1.5  volts.  (40 
to  50  amperes  per  square  inch  of  carbon 
plate  surface  is  a  fair  value  for  a  steady 
load;  75  to  80  amperes  may  be  past  for 
short  periods. — Ed.) 

Contributed  by  ALBERT  H.  BEILER. 


A  NOVEL  WINDOW  ATTRACTION. 

This  display  is  to  be  used  chiefly  as  a 
flash-light  window  decoration.  It  is  to  rep- 
resent a  large  flash-light.  A,  is  a  piece  of 
stove-pipe.  P,  is  a  piece  of  wood  cut  cir- 
cular to  fit  end  of  stove-pipe.  M,  is  a 
40-watt  electric  lamp.  N,  is  socket  to  hold 
lamp.  E,  is  a  reflector.  K,  is  an  imita- 
tion push-button.  S,  is  stand  to  support 
display.  W,  is  concealed  wiring.  L,  is  the 
lens  and  H  is  a  front  glass  taken  from  an 


This    Nifty    Electrical    Window  Attraction 
Comprises  a  Large  Dummy  Flash-Light,  the 
Lamp  Within  It  Being  Winked  On  and  Off 
By  a  Flasher. 

automobile.  The  drawing  will  explain  it- 
self. A  flasher  can  be  put  into  the  circuit, 
to  give  a  more  novel  effect. 

This  display  is  worth  anyone's  time,  and 
the  cost  is  small. 

Contributed  by  OTTO  G.  CLAWSON. 


398 


THE  ELECTRICAL  EXPERIMENTER 


October,  1917 


How  to  Make  a  Magnetic  Polarity  Indicator 

By  Samuel  Cohen 


It  sometimes  happens  that  the  polarity 
of  a  current  in  a  line  is  required  and  no 
available  means  is  at  hand.    The  writer 


A    Watch    Style    Polarity    Indicator   of  the 
Magnetic  Type  Appeals  to  Every  Electrical 
Man.      Details  for    Making   One   Are  Given 
Herein. 


was  in  this  predicament  at  one  time  and 
hurriedly  constructed  an  instrument  which 
served  the  purpose  very  well,  and  thought 
it  worth  while  to  show  the  readers  of  this 
journal  how  to  make  one  of  them. 

The  accompanying  photograph  shows  the 
instrument  complete.  Note  the  relative 
size  of  the  same.  The  instrument  consists 
of  a  watch  case,  in  which  a  dial,  supported 
on  a  pivoted  permanent  magnet,  is  enclosed. 
This  magnet  is  acted  upon  by  a  magnetic 
field  produced  by  a  small  electro-magnet 
coil. 

The  constructional  details  are  given.  It 
will  be  noted  that  actual  sizes  are  not 
shown,  as  it  depends  mainly  upon  the  size 
of  the  watch  case.  The  field  or  exciting 
magnet  consists  of  a  core  made  as  indi- 
cated in  Fig.  1.  The  length  A  is  equal  to 
the  inside  diameter  of  the  watch,  while 
the  width  B  should  not  exceed  Y%  of  an 
inch.  The  width  of  the  pole  pieces  C  will 
depend  upon  the  general  features  of  the 
case.  The  height  is  determined  by  the 
depth  of  the  case.  It  should  be  made  as 
high  as  space  permits,  in  order  to  enable 
one  to  close  the  back  of  the  case  with  the 
cover.  The  winding  of  this  field  will  de- 
pend on  the  character  of  work  you  desire 
to  use  the  meter  for.  The  following  table 
has  been  made  to  facilitate  matters.  The 
resistance  of  the  coil  for  the  three  volt- 
ages should  be  as  follows:  110  volt  cir- 
cuit—  1100  ohms  ;  32  volts  —  256  ohms  ;  and 
6  volts  —  25  ohms.  The  number  of  turns 
and  size  of  wire  is  greatly  dependent  on 
the  size  of  the  magnet  and  the  figures 
can  readily  be  obtained  from  any  wire 
table. 

The  indicating  face  of  the  watch  is 
removed  and  in  its  place  another  circular 
brass  disc  1,  Fig.  2  is  placed.  The  mag- 
netic vane  2  is  made  as  shown,  the  length 
of  which  should  be  three-quarters  the 
diameter  of  the  disc  1  and  the  width  5/16 
of  an  inch.  It  is  made  of  the  best  tool 
steel,  preferably  spring  steel,  and  should  be 
magnetized  in  the  usual  manner  by  the 
application  of  a  strong  permanent  or  elec- 
tro-magnet. A  pivoted  rod  3,  is  fastened 
to  the  center  of  the  magnet  as  shown. 
This  is  used  to  support  the  magnet  be- 
tween the  standard  4,  which  is  a  piece  of 
stiff  brass  bent  as  indicated  and  soldered 
to  the  rear  of  the  plate  1.  A  small  hole 
is  made  on  the  interior  face  of  this  stand- 


ard and  exactly  opposite  this  another  hole 
is  made  on  the  plate  1,  in  order  to  hold 
horizontally  the  pivoted  magnet  shaft  3. 
A  paper  dial  5,  is  fastened  to  the  ends  of 
the  magnet.  Two  dial  holes  6,6  are  drilled 
in  the  plate  1.  These  should  so  be  situ- 
ated that  they  cover  the  ends  of  the  dial  5. 

The  field  or  exciting  magnet  A,  is  placed 
in  a  horizontal  position  while  the  magnet 
2,  is  stationed  in  a  vertical  position.  By 
the  passage  of  a  current  of  electricity  thru 
the  coil  in  one  direction,  the  needle  will 
be  displaced  in  one  direction,  but  it  will 
change  its  direction  if  the  terminals  of 
the  coil  are  reversed. 

If  a  known  polarity  indicator  is  on  hand 
so  as  to  show  the  direction  of  current  in 
the  line,  it  is  very  easy  then  to  calibrate 
the  instrument  or  the  following  simple 
chemical  polarity  indicator  can  be  used. 
Place  the  two  current  terminals  in  a  sliced 
potato  and  the  surface  about  the  wire 
which  bubbles  indicates  the  negative  ter- 
minal. Connecting  the  same  two  wires  to 
the  magnetizing  coil  and  knowing  their 
polarity,  it  is  easy  to  mark  either  the  lower 
or  upper  wire  as  the  negative  or  positive. 
So  if  the  lower  wire  is  positive,  then  indi- 
cate by  (-f)  on  the  lower  part  of  the 
dial.  When  the  current  is  flowing  thru 
the  coil  and  as  soon  as  the  current  is  re- 
leased the  indicating  mark  will  disappear. 
The  whole  arrangement  should  be  placed  in 
the    watch    case   and    the   coil  terminals 


Detail  of  Magnetized  Needle  and  Electro- 
Magnet  Used  in  Making  Polarity  Indicator. 


should  be  led  thru  the  bottom  and  top  of 
the  case  by  boring  a  hole  in  each  end  and 
properly  insulated. 

The  time  spent  in  building  this  instru- 
ment will  never  be  regretted  by  the  ex- 
perimenter as  it  will  amply  repay  him  in 
future  service. 


NON-CORROSIVE  COBALT 
ALLOYS. 

A  recent  bulletin  of  the  Canada  Depart- 
ment of  Mines  gives  an  account  of  some 
tests  by  H.  T.  Kalmus  and  K.  B.  Blake  on 
non-corrosive  cobalt  alloys.  The  addition 
of  cobalt  or  nickel  to  iron  proved  bene- 
ficial as  far  as  non-corrosive  qualities  are 
concerned.  Cobalt  is  somewhat  better  than 
nickel  in  this  respect.  The  extent  of  cor- 
rosion appears  to  be  dependent  on  time  of 
exposure,  but  is  not  a  simple  function  of 
the  cobalt  content.  A  small  addition  of 
copper  also  seems  to  reduce  the  atmospheric 
corrosion  of  American  spigot  iron. 


AN  INDUCTIVE  OCEAN  CABLE 
SYSTEM. 

I  think  I  have  an  improvement  over  Mr. 
Schultz's  invention  as  described  in  the 
April  issue.  Instead  of  using  buoys  I  pro- 
pose that  a  submarine  cable  be  laid  on  the 
exact  route  of  the  ship.  This  would  be  a 
guide  for  the  vessel  as  well  as  a  means 
of  communication  with  the  shore  by  means 
of  an  induction  system.  Thus  the  ship  will 
always  be  on  the  safe  route  by  constantly 
communicating  with  the  shore,  especially 
in  a  heavy  fog  and  gale.  In  war  time  a 
guiding  scheme  like  this  would  s.ave  many 
a  ship  from  being  blown  up  by  mines.  A 
scheme  like  this  would  be  invaluable  on 
a  route  running  among  dangerous  rocks 
and  reefs.  In  time  of  danger,  help  can  be 
summoned  without  delay.  This  idea,  I 
think,  is  as  good  as  wireless  telegraphy,  if 
not  better,  because  wireless  telegraphy  will 
not  guide  a  ship  in  dangerous  waters  or  be 
so  efficient.  By  means  of  my  proposition 
the  use  of  buoys  in  dangerous  waters  would 
be  eliminated,  and  buoys  can't  always  be 
depended  upon. 

Contributed  by  HARRY  E.  FUCHS. 

{This  scheme  would  be  feasible  if  the 
cable  was  but  a  short  distance  underneath 
the  ship.  But  to  obtain  an  inductive  effect 
over  500  to  2,000  feet  of  depth  is  not  pos- 
sible for  the  reason  that,  first,  the  iron  clad 
cable  absorbs  most  of  the  inductive  currents 
and,  second,  because  only  a  few  volts  and 
less  than  1/100  of  an  ampere  can  be  used  for 
submarine  telegraphy.  When  stronger  cur- 
rents are  used,  the  cable — which  is  nothing 
but  an  immense  condenser — breaks  down, 
as  happened  to  several  of  our  first  trans- 
atlantic cables. — Editor.) 


A   HOME-MADE  FREQUENCY  IN- 
DICATOR. 

In  the  absence  of  a  more  expensive  in- 
strument, a  frequency  indicator  which  gives 
good  results  has  been  constructed,  as  shown, 
says  an  Electrical  World  writer,  from  a 
telephone  receiver  as  follows :  Eight  strips 
of  0.006  in.  spring  steel  5/64  in.  wide  by 
2  in.  long  marked  (1)  in  the  side  view  of 
the  receiver  shown  in  the  accompanying 
illustration  were  clamped  radially  between 
two  burrs  (6)  on  the  cork  (3)  by  means 
of  a  wood  screw  (7).  The  contacting  metal 
surfaces  were  tinned  and  sweated  together. 
The  whole  was  then  mounted  on  the 
diafram  of  a  telephone  receiver  (5)  by 
means  of  beeswax.  The  magnet  had  been 
previously  removed  from  the  receiver,  and 
the  brass  screw  (8)  replaced  by  one  of 
steel. 

For  use  with  110  volts  it  was  found  nec- 
essary to  use  a  400-ohm  resistance  in  series. 
In  calibrating  this  device  a  motor-generator 
of  adjustable  frequency  was  used  in  con- 
nection with  a  standard  instrument.  After 
setting  the  machine  at  56  cycles,  one  of 
the  springs  was  carefully  clipt  off  at  the 
end,  piece  by  piece,  until  it  set  up  a  strong 
vibration.  The  machine  was  then  raised 
to  57,  and  the  operation  repeated  with  the 


A  Useful  Frequency  Meter  Made  from  a  Tel- 
ephone  Receiver  and   a    Few   Steel  Reeds, 
Properly  Calibrated. 


next  spring,  and  so  on  up  to  63  cycles. 
Each  spring  thereafter  vibrated  only  in  re- 
sponse to  the  frequency  to  which  it  was 
adjusted. 


October,  1917 


THE  ELECTRICAL  EXPERIMENTER 


399 


CONSTRUCTING  A  Va  K.W.  HIGH 
FREQUENCY  OUDIN  COIL. 
By  George  Sutton,  Jr. 

FIRST  I  procured  a  card-board  tube" in 
which  a  Pyrene  fire  extinguisher  was 
packed,  at  a  local  auto  supply  store. 
The  size  of  mine  is  10  in.  long  and  4  in.  in 
diameter.  Next  I  painted  the  card-board 
cylinder  with  3  coats  of  orange  shellac  to 
make  it  stiff.  Then  I  constructed  the  wood- 
en heads ;  they  may  be  turned  up  on  a 
lathe  or  with  a  compass  saw  if  no  lathe  is 
available.  One  head  measures  4^  in.  in 
diameter  and  the  other  head  3^4  in-  m 
diameter.  The  smaller  head  is  eventually 
fastened  to  the  base  to  hold  the  cylinder  in 
place.  I  turned  the  top  head,  which  is 
made  all  in  one  piece  as  shown,  and  put 
the  heads  on  the  cylinder  and  mounted  it 
between  the  centers  of  my  lathe.  The 
cylinder  was  wound  with  one  layer  of  No. 
26  enameled  magnet  wire,  between  the  turns 
of  which  I  wound  a  layer  of  heavy  linen 
thread  to  separate  the  turns.   I  started  Yi  in. 


Prim.  -  ■ 


■Hf/nefosec.         ^Ho/eformre  @ 


from  the  top  and  finished  1^4  in.  from  bot- 
tom ;  this  will  take  about  eight  hundred 


2"  brass  bo// 


4 id/a, 


Winding  so/dered 
fo  brass  rod  ■ — 


Secondoru- 


Secondory  /ermma/_ 


1 


moden 
'dowel 


Plan  View  of  Small  High  Frequency  Coil  of 
the  Oudin  Type. 


Details  of  Small  Oudin  Coil  Suitable  for  Use 
with  !/4  K.W.  Step-Up  Radio  Transformer  or 
6  to  8  Inch  Spark  Coil. 


turns.  Two  holes  are  punched,  one  at  A 
and  one  A1.  The  top  turn  is  run  thru  the 
hole  A,  and  connected  to  the  brass  ball  on 
top;  the  bottom  turn  is  run  thru  hole  A1 
and  thru  hole  A2  and  connected  to  binding 
post  E.  After  the  cylinder  is  wound  it  is 
necessary  to  coat  it  thoroly  with  several 
coats  of  shellac,  as  this  prevents  the  sparks 
from  jumping  between  turns  and  also  holds 


the  wire  in  place.  Now  comes  the  base;  I 
used  a  piece  of  yellow  pine  12  in.  square, 
34  in.  thick,  then  gave  it  several  coats  of 
black  asphaltum  paint.  The  brass  ball  may 
be  obtained  from  a  bed-post  or  may  be 
purchased  from  a  local  hardware  dealer. 
The  secondary  cylinder  was  put  in  place, 
the  bottom  turn  of  secondary  connected 
with  binding  post  E,  and  the  top  turn  con- 
nected with  the  brass  ball.  I  then  con- 
structed the  primary ;  first  I  took  a  ring  of 
card-board  5  in.  inside  diameter  and  1  in. 
wide  and  fastened  one  end  of  the  brass 
tape  by  binding  it  with  friction  tape.  The 
primary  is  made  of  8  or  9  turns  of  1  in. 
brass  or  copper  ribbon  separated  by  a  layer 
of  corrugated  card-board.  When  the  pri- 
mary is  completed  it  is  bound  by  winding 
some  friction  tape  around  the  outside ;  the 
inside  turn  of  primary  is  also  connected  to 
binding  post ;  this  flexible  wire  has  a  clip 
attached  to  it  and  is  connected  to  binding 
post  D,  and  run  thru  hole  F,  so  as  not  to 
interfere  with  making  connections  with 
as  many  turns  of  the  primary  as  may 
be  needed.  Four  standard  porcelain 
insulators  are  used  for  feet.  Sparks  from 
8  to  12  in.  long  can  be  drawn  from  this 
Oudin  transformer  when  excited  by  Y\  K. 
W.  wireless  transformer. 


Prim. 


f 


H.TCond 


Bo//  /ermino/ 


f 'KM  s/ep-up, 
fronsf. 


To  1/0  ¥./>£. 


Connections  for  Oudin   Coil,   Showing  How 
the  Secondary  and   Primary   Windings  Are 
Connected  Together. 


Trials  of  a  Troubleshooter 

By  THOS.  W.  BENSON 


HAVE  you  ever  indulged  in  that  great 
indoor   sport  of  "trouble-shooting." 
Especially  that  brand  of  trouble  that 
infests  the  network  and  web  of  a  telephone 
system  in  a  large  town.  NO? 

Never  stood  by  when  a  cable  "blows  up" ; 
when  pair  after  pair  goes  bad?  Never 
held  your  breath  as  that  infernal  meter  on 
the  test  table  swings  over  and  in  its  cold, 
impersonal  way  quietly  shows  "dead  pairs," 
"shunts,"  "opens,"  "grounds,"  and  what  not, 
knowing  meanwhile  that  you  are  going  out 
to  shoot  the  said  trouble?  Great  life! 
Take  it  from  your  Uncle  Dudley. 

Paradise,  according  to  the  late  Elbert 
Hubbard,  is  a  town  with  only  one  telephone 
system.  Perhaps  so,  but  you  can  stake 
your  last  jitney  against  a  cancelled  postage 
stamp  that  the  said  system  keeps  the  record- 
ing angel  busy  at  times,  even  more  so  when 
old  Jupe  Pluvius  lets  drive  with  a  rain 
storm. 

But  there  are  some  troubles  that  seem  to 
have  no  rhyme  or  reason.  This  is  the  case 
when  transmission  is  poor.  There  are  sev- 
eral million  different  things  that  can  cause 
this  and  the  majority  are  not  in  the  text 
book.  It  is  simply  a  case  of  pulling  wires 
and  tightening  screws  till  the  trouble  goes 
off. 

For  instance,  a  certain  'phone  goes  bad 
and  you  jump  over  to  see  what  the  "bug"  is. 
But,  curses,  the  instruments  test  O.K.  The 
cord  seems  to  have  a  light  shunt  on  it  so 
you  put  in  a  new  cord.  But  behold,  next 
day  the  same  'phone  is  on  your  bogey  with 
the  same  trouble.  An  examination  shows 
that  the  cord  is  at  fault  again.  And  that 
was  a  perfectly  good  cord  when  put  in  a 
few  hours  before.    Well,  we  will  put  an- 


other one  in  and  see  how  that  works. 
Test  table  reports  clear  and  away  you  go. 

But,  the  next  day  sees  you  back  at  the 
old  stand.  Now  what  in  the  name  of  a 
bald-headed  South  African  flea  is  wrong? 
The  cords  look  perfect,  not  wet  or  spotted. 
(It  is  practically  impossible  to  pick  up  a 
single  wet  spot  on  a  cord.)  A  new  cord 
and  the  'phone  is  reported  clear.  Yes,  you 
are  now  shooting  trouble  with  a  great 
big  "T." 

Perhaps  this  will  continue  till  you  hap- 
pen in  on  the  'phone  and  find  that  blamed 
pet  poddle  snapping  at  the  cord.  Yep, 
those  toy  hounds  can  wet  that  cord  suf- 
ficiently by  biting  on  it  till  the  relay  at 
central  drops  over  and  flashes  up  on  the 
board. 

Of  course  you  can't  warn  the  dog  off, 
but  you  would  be  surprised  at  the  number 
of  times  you  have  to  warn  off  the  "PEE- 
PUL."  They  seem  to  think  that  a  tele- 
phone cord  makes  a  good  washline  to  dry 
handkerchiefs,  or  support  wet  umbrellas,  or 
use  it  for  a  pincushion.  I  suppose  it  does 
take  all  kind  of  people  to  make  up  our 
old  planet.  Sometimes  they  decide  to 
shorten  the  cord  and  use  a  safety  pin  for 
the  purpose.  Of  course  that  means  a  call 
from  the  'phone  Doctor  who  has  to  oper- 
ate and  remove  the  obstruction  from  the 
path  of  speech. 

But,  as  in  the  previous  case  obstruc- 
tions do  not  always  stand  up  and  holler 
at  the  "Doc."  No  indeed  not ;  take  the 
case  of  the  "Mysterious  Shunt." 

Tests  from  the  table  showed  that  a  per- 
fect shunt  existed  on  a  certain  'phone. 
On  arriving  the  troubleman  took  down  the 


receiver  and  found  everything  O.  K.  No 
shunt  or  anything  else  seemed  to  be  in 
that  vicinity.  The  test  table  swore  that 
was  the  'phone  reported  in,  but  now  it 
tested  clear. 

But  it  came  to  pass,  as  the  stories  go, 
that  an  equally  good  short  made  itself 
apparent  the  following  day.  Again  there 
was  no  trouble  when  "Doc"  arrived.  "The 
man  is  crazy,"  was  his  diagnosis  of  the 
trouble.  And  still  it  came  and  went,  on 
one  day,  clear  for  a  while,  then  on  again. 
Pairs  were  changed  at  the  cable  box. 
"Hah,  faulty  pair,"  was  the  troubleman's 
exultant  exclamation,  as  the  'phone  was 
clear  for  several  days.  But — that  shunt 
still  hung  around  and  dropt  on  after  a 
week. 

"Doc"  made  up  his  mind  he  would  kill 
that  trouble  or  stay  there  the  rest  of  his 
days.  He  fust  around,  asked  for  a  ring 
that  meant  something  and  finally  noted 
that  the  shunt  would  go  on  as  soon  as  the 
'phone  was  called  and  drop  off  later.  This 
looked  like  a  case  of  renewing  the  fuses  in 
the  lightning  arrester  and  he  started  up 
to  see  if  they  were  faulty.  Having  looked 
at  these  previously  they  were  alright,  but 
on  this  day  he  noted  the  fact  that  a  new 
curtain  had  been  hung  over  the  window 
above  which  the  lightning  arrester  was 
located.  And  said  curtain  had  a  brass 
rod  that  just  about  touched  the  ends  of 
the  fuses.  When  a  ring  came  it  would 
jump  thru  the  lacquer  on  the  rod  and 
short-circuit  the  line  and  mate;  the  least 
little  vibration  would  then  break  the  cir- 
cuit and  the  line  cleared  up.  Yes,  you 
could  almost  count  the  number  of  rings 
(Continued  on  page  427) 


400 


THE  ELECTRICAL  EXPERIMENTER 


October,  1917 


CONVERTING  AN  INTEGRATING 
WATT-METER  INTO  AN 
INDICATING  TYPE. 
By  Geo.  Sturley. 

Have  you  an  old  integrating  watt-meter 
among  the  things  you  do  not  use?  If  so, 
perhaps  you  can  make  good  use  of  it  by 


Practically   All    Tests   On    Alternating  Cur- 
rent Circuits  Call  for  an   Indicating  Watt- 
Meter.    Here  is  a  Way  to  Make  One  from  an 
Old  Integrating  Watt-Hour  Meter. 


trying  the  following.  The  idea  is  to  re- 
build an  integrating  meter  into  an  indicat- 
ing one.  This  is  done  by  removing  all  the 
gear-trains  and  dials  of  the  integrating  sys- 
tem and  attaching  to  the  shaft  of  the  ro- 
tor a  hair-spring  taken  from  an  alarm  clock. 
Then  the  twisting  effort  at  the  shaft  will 
rotate  the  cylinder  part  way  around  against 
the  tension  of  the  spring.  A  paper  scale 
(Fig.  1.)  marked  with  drafting  ink  is  glued 
on  the  cylinder  and  all  desired  calibrations 
marked  on  it. 

The  writer  made  such  an  instrument 
from  a  Fort  Wayne  Type  K  meter  of  5 
ampere  rating  and  it  reads  up  to  750  watts. 
And  when  the  scale  shows  a  reading  of  100 
watts  or  better,  the  meter  is  sensitive  to  3 
watts. 

A  paper  scale,  was  made  from  a  strip  of 
good  ink  paper  three  quarters  inch  wide, 
and  long  enough  to  reach  around  the 
cylinder.  Lines  about  1/8  inch  apart  were 
drawn  for  scale  divisions.  The  magnets 
in  the  meter  were  left  in  place  as  they 
greatly  improved  the  damping  of  the  in- 
strument. As  this  meter  has  a  revolving 
scale,  the  pointer  is  arranged  stationary,  and 
is  nothing  more  than  a  heavy  cross-line 
drawn  on  a  piece  of  card  board  which  is 
fitted  in  the  glass  window  where  the  dials 
used  to  be.  Fig.  2.  When  the  meter  is 
not  indicating,  the  zero  on  the  scale  is  right 
in  line  with  the  pointer.  The  meter  was 
calibrated  by  a  lamp  bank,  using  different 
numbers  and  sizes  of  lamps  for  the  calibra- 
tions desired.  With  a  5  ampere  meter  it  is 
inadvisable  to  calibrate  higher  than  750 
watts.  This  Fort  Wayne  style  of  meter  is 
the  easiest  form  to  remodel.  In  the  case 
of  changing  a  meter  having  a  disc-rotor, 
you  will  have  to  turn  it  bottom-end  up  for 
a  front,  and  a  circular  scale  having  radial 


markings  will  be  required.  Also  a  hole  will 
have  to  be  cut  in  the  bottom  to  view  the 
scale  thru. 

The  meter  can  be  used  in  connection 
with  a  wireless  sending  set  to  conveniently 
read  at  any  time  how  much  power  is  be- 
ing used.  When  anyone  asks,  "How  much 
power  (in  true  watts)  are  you  using?",  you 
can  tell  the  amount  at  once.  Fig.  3  is  a 
hook-up  whereby  the  meter  is  permanently 
wired  in  with  the  primary  of  the  "bug", 
and  a  snap  switch  when  closed  shunts  the 
current  coils  in  the  meter  out  when  no 
readings  are  desired.  When  a  reading  is 
desired,  open  the  snap  switch  and  hold 
down  the  key.  Also  the  meter  may  prove 
useful  in  determining  the  power-factor  in 
your  transformer  primary  circuit,  if  you 
have  a  volt  meter  and  ammeter.  The  power 
factor  is  determined  by  dividing  the  actual 
watts  (watt-meter  reading)  by  the  apparent 
watts  (volts  x  amps).  If  you  aim  to  im- 
prove your  set,  this  power  factor  if  kept 
up  to  a  high  value  will  mean  your  trans- 
former is  actually  handling  more  power. 


USE  OF  PERMANENT  MAGNET  IN 
A.C.  TO  D.C.  RECTIFIER. 

In  the  May,  1916,  issue,  there  was  de- 
scribed a  magnetic  rectifier,  and  finding  it 
rather  troublesome  to  have  to  use  bat- 
teries for  the  permanent  field  excitation,  I 
found  that  if  a  steel  bar-magnet  was  sub- 
stituted instead  of  the  electro-magnet,  the 
device  would  work  as  well  and  save  the 
trouble  and  cost  of  the  batteries.  [Note: 
By  referring  to  the  May.  1916,  issue,  full 
description  will  be  found.] 

Contributed  by  A.  ALLIN. 


Extremely   Simple    Form    of   Vibrating  A.C. 
to   D.C.    Rectifier   Made   With   a  Permanent 
Magnet  Armature. 


ODDMENTS  FROM  THE  HOUSE- 
HOLD. 

The  experimenter  whose  purse  is  no 
deeper  than  the  average  will  need  to  ex- 
temporize much  of  his  apparatus,  and  if 
carefully  made  such  appliances  will  be  quite 
as  serviceable  as  the  shop-made  article, 
tho  probably  lacking  in  finish.  No  oppor- 
tunity should  be  lost  to  secure  unclaimed 
oddments  of  household  utensils.  An  ex- 
cellent electroscope  can  be  made  from  a 
lamp  chimney,  "plugging  the  top  with  sul- 
fur and  embedding  the  wide  end  in  paraffin 
wax  contained  in  a  flat  tin ;  part  of  a 
broken  window  makes  a  good  fulminating 
pane  if  the  sharp  edges  are  rubbed  down 
with  a  file  or  emery  cloth,  and  many  other 
examples  might  be  quoted. 

Contributed  by  H.  J.  GRAY. 


AN  ELECTRICAL  SHUTTER  RE- 
LEASE FOR  CAMERAS. 

Following  is  a  description  of  an  electrical 
release  for  camera  shutters,  to  be  used  in 
photographing  wild  animals  and  birds  from 
a  distance.  It  can  also  be  used  when  the 
experimenter  desires  to  take  his  own  pic- 
ture, etc. 

In  the  accompanying  drawing  (Fig.  1), 
A  is  the  main  part  of  the  frame,  or  base. 
It  is  made  of  xA~'m-  square  brass  rod,  about 
6  in.  long.    It  is  bent  at  right  angles  about 


4  in.  from  one  end,  and  has  a  1/16-inch 
slot  cut  in  the  end  of  the  short  leg. 

B  is  the  clamp  to  hold  the  release  in 
place  on  the  bed  of  the  camera.  It  also 
is  made  of  ^-in.  square  brass  rod,  and 
is  bent  as  shown.  These  bends  CANNOT 
be  made  cold. 

C  is  the  movable  lever,  of  x  1/16- 

in.  brass  strip,  about  5  in.  long.  It  is 
drilled  at  the  places  shown  in  drawing,  and 
has  a  short  slot  cut  where  the  rivet  7 
passes  thru.  The  part  X  of  lever  C,  in- 
dicated by  dotted  lines,  is  turned  up  to  a 
horizontal  position.  This  forms  a  broad 
striking  surface  for  the  release,  and  is 
covered  with  leather. 

D  is  a  solenoid,  size  1  in.  x  1%  in.  It 
is  formed  of  an  old  hard  rubber  foun- 
tain pen  barrel  or  other  tube  having  an 
inside  diameter  of  %  in.,  fitted  with  two 
1/16-in.  liber  washers,  of  lyi-in.  diameter, 
wound  with  No.  22  gage  enameled  magnet 
wire. 

E  is  the  core  of  the  solenoid,  of  J^-in. 
soft  iron  rod,  \%-'m.  long.  It  has  a  1/16-in. 
slot  cut  in  its  upper  end  and  a  hole  drilled 
for  rivet  7. 

F  is  a  spring  to  draw  lever  C  upward, 
away  from  the  solenoid.  The  upward 
movement  of  lever  C  is  limited  by  G, 
which  is  a  short  section  of  cheap  watch 
chain  or  other  small  chain,  the  upper  end 
of  which  is  fastened  to  a  hole  in  C,  and 
the  lower  end  to  screw  5. 

H  is  a  block  of  hard  fiber,  \%  in.  x  1  in. 
x  %  in.,  on  which  are  mounted  binding 
posts  I. 

I  is  the  clamping  screw,  made  of  an 
8-32  battery  binding  post  screw,  with  the 
head  filed  flat  and  the  lower  end  fitted 
tightly  in  a  fiber  washer  for  a  handle. 
2,  3,  4  and  5  are  6-32  brass  machine  screws. 
6  and  7  are  small  rivets. 

A  small  dashpot  added  between  the 
solenoid  and  the  upright  part  of  frame 
will  make  the  action  much  smoother  and 
soften  the  jar  to  the  camera,  but  it  is 
not  absolutely  necessary. 

Fig.  2  is  given  merely  as  a  suggestion 
for  a  method  of  mounting  the  solenoid.  A 
piece  of  sheet  brass  is  cut  to  the  shape 
shown  at  A,  and  is  bent  on  the  dotted 


A  Good  Form  of  Magnetic  Shutter  Release 
for  Cameras  Is  Here  Shown.    It  Can  Be  At- 
tached and  Detached  in  a  Few  Moments. 


lines  to  the  shape  of  B.  It  is  then  slipt 
over  the  solenoid  and  fastened  to  the  frame 
by  a  screw  dropt  thru  the  solenoid  into 
the  small  hole  in  clip  and  screwed  into 
the  frame.  This  will  hold  the  solenoid 
firmly. 

Contributed  by  J.  E.  HENDERSON,  JR. 


October,  1917 


THE  ELECTRICAL  EXPERIMENTER 

Chemical  Action  of  Storage  Batteries 

By  ALBERT  W.  WILSDON 


40 


MANY  experimenters  have  fre- 
quently used  storage  batteries 
but  have  possibly  never  stopt  to 
inquire  as  to  the  action  which 
takes  place  in  them.  To  obtain 
best  results  in  any  branch  of  endeavor,  it  is 
necessary  to  understand  the  fundamental 
principles  which  govern  each  individual 
case.  This  is  also  true  as  regards  storage 
batteries.  If  improperly  taken  care  of  or 
handled,  they  will  not  give  satisfactory  re- 
sults, the  same  as  if  a  gas  engine  were  to 
be  permitted  to  be  run  without  water,  oil 
or  cleaning. 

The  lead  storage  battery  in  the  charged 
state  consists  of  a  positive  plate  of  lead 
peroxide  (PbO>)  and  a  negative  plate  of 
finely  divided  lead,  both  being  introduced 
into  sulfuric  acid  (H2S04)  of  about  1.2  sp. 
gr.  When  discharged  the  surface  of  the 
plates  has  been  changed  to  lead  sulfate 
(PbSOi).  The  plates  may  be  brought  back 
to  their  original  condition  by  sending  a 
current  thru  the  battery  in  the  reverse  di- 
rection. 

During  the  formation  the  plates  are  fre- 
quently permitted  to  stand  in  some  corrod- 
ing solution  of  acids  that  produce  a  thick 
layer  of  lead  sulfate  (PbS04),  for  a  certain 
time.  The  lead  sulfate  may  then  be  re- 
duced electrolytically  to  lead,  or  oxidized 
to  lead  peroxid  (Pb02).  When  acids  other 
than  sulfuric  are  used,  these  must  be 
thoroly  washed  out  before  the  battery  is 
ready  for  use.  For  instance,  a  mixture  of 
nitric  and  sulfuric  acids  would  have  the 
effect  of  producing  a  layer  of  sulfate. 

By  another  method  the  plate  is  elec- 
trolyzed  as  an  anode,  but  lead  peroxid 
(Pb02),  which  would  protect  the  plate 
from  further  action,  is  prevented  from 
forming  by  adding  some  salt  or  acid  to  the 
solution,  the  union  of  which  separates  at  a 
lower  potential  than  the  peroxid  ion  and 
causes  the  production  of  sulfate.  Lead 
sulfate  (PbSOi),  being  a  non-conductor, 
requires  the  lead  below  to  be  penetrated  by 
the  current,  and  as  much  sulfate  may  be 
produced  in  one  step  as  is  desired.  Such 
additions  are  acetates,  tartarates,  chlorids, 
nitrats,  chlorats,  perchlorats,  and  the  cor- 
responding acids. 

Peroxid  is  not  always  formed  on  a  lead 
anode  in  sulfuric  acid,  even  when  no  sub- 
stance is  added  to  the  solution  to  prevent 
it,  which  is  made  apparent  by  the  fact  that 
the  lead  plate,  which  is  the  anode,  on  dis- 
charging, becomes  covered  with  sulfate.  If 
therefore,  a  lead  plate  is  short-circuited  in 


+  0.5 

|  o-o 

^  -0.5 
-1* 

f 

0                   2  4- 

Fig.  2.    Temperature  Coefficient  of  Electro- 
motive  Force  of   Lead   Storage    Battery  As 
Function  of  the  Acid  Concentration. 

a  solution  of  sulfuric  acid  with  a  peroxid 
plate,  it  will  become  covered  with  sulfate, 
proportional  in  amount  to  the  current  that 
flows  thru  the  plate. 

In  the  Faure  type  storage  cell  the  plates 
consist  of  lead  with  about  5  per  cent  of 
antimony.  The  active  material  is  made  by 
making  a  paste  of  lead  oxid  (PbO)  and 
sulfuric  acid,  and  applying  it  to  grooves 


cast  in  the  supporting  grid.  The  paste  sets 
and  becomes  hard,  after  which  it  is  changed 
to  lead  sponge  and  peroxid  by  electrolysis 
in  a  solution,  which  may,  or  may  not  be, 
sulfuric  acid. 

The  theory  of  the  lead  storage  battery 
which  is  generally  accepted,  is  known  as  the 
"sulfate  theory",  and  is  due  to  Gladstone 
and  Tribe.  Sulfuric  acid  combines  with  the 
plates  on  discharge,  and  is  set  free  on 
charge,  according  to  this  theory.  On  dis- 
charge hydrogen  is  deposited  on  the  lead 
peroxid  which  reduces  it  to  lead  oxid 
(PbO),  which  is  changed  to  lead  sulfate 
(PbS04),  as  represented  by  the  equation: 

(i) 

Pb02     +      H2    +    H.SO,   =  PbS04  +  2H.O 

Lead       Hydrogen       Sulfuric  Lead  Water 

Peroxid                           Acid  Sulfate 

At   the   same   time   the  sulfate  radical 

(SOi)  is  deposited  on  the  lead  plate  and 

changes  to  lead  sulfate : — 


(2) 


Pb     +     S04  =  PbS04 
Lead         Sulfate  Lead 
Radical  Sulfate 


The  sum  of  these  two  equations  is  the 
total  change  in  the  storage  battery  on  dis- 
charge : — ■ 

(3)  Pb02  +  Pb  +  2H2S04  =  2PbS04  +  2H,0 
Lead       Lead     Sulfuric       Lead  Water 

Peroxid  Acid  Sulfate 

When  in  the  discharged  state  both  plates 
are  covered  with  sulfate.  Upon  charging, 
the  reaction  on  the  positive  plate  is  : — 

(4)  PbS04  +  S04  +  2H..0  =  Pb02  +  2H2S04 

Lead      Sulfate     Water      Lead  Sulfuric 
Sulfate    Radical  Peroxid  Acid 

While  in  the  negative  plate : — 

(5)  PbS04     +     H2  : 

Lead  Hydrogen 
Sulfate 


Pb     +  H2S04 
Lead  Sulfuric 
Acid 


The  sum  of  the  last  two  equations  (4 
and  5)  represents  what  takes  place  in  the 
whole  battery  on  charging : — 

(6)  2PbS04  +  2H20  =   Pb02  +  Pb    +  2H2S04 

Lead  Water  Lead  Lead  ,  Sulfuric 
Sulfate  Peroxid  Acid 

This  equation  is  just  the  reverse  of  the 
sum  of  the  first  two  equations  (No.  3),  and 
the  changes  taking  place  both  on  discharge 
and  charge  may  be  represented  by  the  fol- 
lowing reversible  equation : — 

(7)  Pb02  +  Pb    +    2H2S04      2PbS04  +  2H20 

Lead  Lead  Sulfuric  Lead  Water 
Peroxid  Acid  Sulfate 

From  right  to  left  this  represents  the 
charge,  and  from  left  to  right  the  discharge. 

By  measuring  the  electromotive  force 
(e.m.f.)  of  different  oxids  of  lead  and  hy- 
drats  of  lead  on  lead  against  a  zinc  elec- 
trode and  comparing  with  a  charged  posi- 
tive plate  it  was  shown  that  the  charged 
positive  plate  is  the  peroxid  of  lead  and 
not  some  other  oxid  or  hydrat. 

The  tabulated  results  being : 


Pb/Pb20 

Pb/PbO 

Pb/Pbs04 

Pb/HoPb03 

Pb/PbO- 


— Zn  0.42  volt 
— Zn  0.46  volt 
— Zn  0.75  volt 
— Zn  0.96  volt 
— Zn  0.41  volt 


A  charged  plate  has  a  potential  of  2.4 
volts,  showing  that  lead  peroxide  is  the 
compound  that  exists  on  the  positive  plate. 

Kohlrausch  and  Heim  showed  by  measur- 
ing the  specific  gravity  of  the  acid  on 
charge  and  discharge  that  the  production 
of  sulfate  on  each  plate  was  proportional 
to  the  quantity  of  electricity  that  had  been 
past  thru  the  cell ;  the  density  changing  ex- 
actly in  proportion.    A  calculation  of  the 


change  in  specific  gravity  by  means  of 
equation  7  agrees  with  that  found.  The 
calculation  is  as  follows  :—  The  uncharged 
battery  contained  3350  cubic  centimeters  of 
acid  of  1.115  sp.  gr.  corresponding  to  16.32 
per  cent  acid.  The  total  solution  therefore 
weighed  3735  grams,  and  contained  610 
grams  of  acid,  and  3125  grams  of  water. 
After  charging  with  50  ampere-hours,  ac- 
cording to  equation  7,  the  amount  of  water 


Fig.  1.  Curve  Showing  Change  in  Density  of 
Acid   With   Charge  and  Discharge. 

that  disappeared  was  33.6  grams,  and  the 
amount  of  sulfuric  acid  formed  was  _  183 
grams.  The  solution  therefore  contained 
after  charging,  3091  grams  of  water  and 
793  grams  of  sulfuric  acid.  The  total 
weight  was  therefore  3884  grams,  and  the 
amount  of  sulfuric  acid  contained  was  20.42 
per  cent.,  corresponding  to  a  density  of 
1.146.    The  observed  density  being  1.147. 

It  is  quite  evident  that  since  the  acid  be- 
comes more  dilute  on  discharging  a  lead 
battery,  the  electromotive  force  must  de- 
crease with  decreasing  concentration.  The 
table  given  below,  shows  the  relation  be- 
tween the  concentration  of  the  acid  and 
the  electromotive  force,  from  direct 
measurements. 

TABLE. 

Density  of      F'er  Cent  E.M.F. 

H,  S04         H2S04       at  15  Deg.  C. 

I.  050  7.31  1.906 
1.150  20.91  2.010 
1.200  27.32  2.051 
1.300  39.19  2.104 
1.400             50.11  2.330 

It  will  be  noticed  that  the  electromotive- 
force  of  the  lead  storage  battery,  with  the 
concentration  of  acid  ordinarily  used,  has 
the  unusually  high  value  for  a  battery  of 
over  two  volts.  Sulfuric  acid,  if  elec- 
trolyzed  between  platinum  electrodes,  gives 
a  weak  evolution  of  gas  at  1.7  volts  and  at 
1.9  a  strong  evolution.  If  lead  sulfate  were 
spread  on  platinum,  it  would  therefore  not 
be  possible  to  reduce  it  to  lead  and  oxidize 
it  to  peroxid,  for  the  potential  required 
could  not  be  reached.  On  lead,  however, 
the  over-voltage  is  so  great  that  the  gas 
evolution  does  not  take  place  below  2.3 
volts,  which  is  greater  than  the  voltage 
needed  to  change  the  sulfate  in  lead  on  one 
electrode  and  peroxid  on  the  other.  If  it 
were  not  for  this  high  over-voltage  on  lead, 
the  lead  storage  battery  would  be  an  im- 
possibility. 

The  temperature  coefficient  of  the  lead 
storage  battery  for  the  concentration  of 
acid  used  is  positive,  but  on  decreasing  the 
concentration  of  acid  the  temperature  co- 
efficient falls  to  zero  and  then  becomes 
negative.  The  curve  (No.  2)  represents  the 
results  of  experiments  in  which  the  tem- 
perature coefficient  was  determined  between 
0  deg.  and  24  deg.  C.  The  temperature 
coefficient  is  constant  in  value  between  10 
and  71  deg.  C.  The  heavy  line  in  the  plot 
gives  the  experimental  results. 

The  mechanism  of  the  reactions  taking 
place  in  the  lead  storage  battery  has  been 
(Continued  on  page  422) 


402 


THE  ELECTRICAL  EXPERIMENTER 


October,  1917 


th  r  t  j 


This  department  will  award  the  following  monthly  prizes:    First  Prize,  $3.00;  Second  Prize,  $2.00;  Third  Prize,  $1.00. 

The  purpose  of  this  department  is  to  stimulate  experimenters  towards  accomplishing  new  things  with  old  apparatus  or  old  material, 
and  for  the  most  useful,  practical  and  original  idea  submitted  to  the  Editors  of  this  department,  a  monthly  series  of  prizes  will  be  awardedi 
For  the  best  idea  submitted  a  prize  of  $3.00  is  awarded;  for  the  second  best  idea  a  $2.00  prize,  and  for  the  third  best  prize  of  $1.00.  The  article 
need  not  be  very  elaborate,  and  rough  sketches  are  sufficient.  We  will  make  the  mechanical  drawings.  Use  only  one  side  of  sheet.  Make 
sketches  on  separate  sheets. 


FIRST  PRIZE,  $3.00 


SECOND  PRIZE,  $2.00 


THIRD  PRIZE,  $1.00 


AT  LAST!  THE  "COLLAR-BUTTON" 
SWITCH. 

I  give  herewith  a  description  of  a  "col- 
lar-button" switch,  which  I  am  contribut- 
ing to  the  "How-To-Make-It"  Department. 


Somebody's  Been  Reading  Faithfully  Page 
330  of  the  September  "E.  E."  Instead  of  an 
Electrical  Stunt  with  Old  Shoe  Nails,  How- 
ever, We  Are  Presented  with  the  "Collar- 
Button"  Switch,  for  Which  We  Are  All  Duly 
Thankful. 

This  switch  can  easily  be  made  with  a 
collar-button  and  a  small  strip  of  brass. 
By  simply  putting  the  head  of  the  collar 
button  down,  the  switch  is  "on."  This 
small  switch  can  be  used  where  any  bat- 
tery switch  is  needed  and  can  be  quickly 
and  easily  made.  (Bugdom  extends  its 
sincere  thanks,  Albert ! — Editor.) 
Contributed  by 

ALBERT  CHOQUETTE. 


A  SIMPLE  POLARITY  REVERSER. 

The  device  described  and  illustrated 
herewith  is  a  convenient  means  of  changing 
the  polarity  of  a  pair  of  wires,  of  reversing 
small  motors,  etc. 

It  consists  of  a  wooden  base  upon  which 
are  mounted  six  binding-posts  and  a  pair  of 
two-point  switches,  so  connected  by  a  hard- 
rubber  strip  as  to  move  both  the  switches 
at  the  same  time.  The  manner  of  reversing 
the  polarity  at  once  becomes  evident  by  re- 
ferring to  the  diagram.  Connections  from 
the  binding-posts  are  made  in  grooves  on 


hard  rubber  or  fiber  strip 


©_ 


To  derice 


A  Handy  Polarity  Reverser  Constructed  from 
Two   Switch    Blades,    Four   Contact  Points, 
Some  Binding  Posts  and  a  Base. 

the  under  side  of  the  wooden  base. 
Contributed  by 

PETER  J.  M.  CLUTE. 


ADJUSTABLE  LOUD  TALKING 
RECEIVER. 

Manufacturers  of  high-resistance  tele- 
phone receivers  are  well  aware  of  the  ad- 
vantages to  be  gained  by  tuning  the  diaf  ram 
of  the  receiver  to  the  desired  note.  How- 
ever, their's  is  a  compromise.  Nearly  every 
radio  station  emits  a  tone  distinctively  its 
own  and  the  manufacturer  has  to  strike 
a  mean.  Receivers  have  been  developed 
that  were  adjustable  as  to  the  tension 
on  the  diafram  and  worked  with  sat- 
isfaction when  both  diaframs  were  tuned 
alike.  A  receiver  that  can  be  adjusted  in- 
stantly to  any  note  within  a  wide  range 
is  shown  in  the  attached  illustration.  It 
is  designed  particularly  for  use  with  some 
form  of  amplifier  that  allows  of  its  use 
as  a  loud-talker,  but  by  using  high-resist- 
ance windings  it  will  serve  in  place  of  the 
regular  receivers  for  nearby  or  powerful 
stations. 

To  construct  this  receiver  the  shell  of 
a  long  type  telephone  receiver  is  required. 
A  hole  is  drilled  in  the  center  of  the  dia- 
fram and  a  short  brass  bolt  inserted.  The 
threaded  end  of  the  bolt  is  slotted  to  take 


Here's    What    You've    Been    Looking  For, 
"Bugs";  a  Loud  Talking  Telephone  Receiver 
and  Amplifier  Which  May  Be  Adjusted  for 
Different  Currents  and  Circuits. 

a  strip  of  thin  iron  *4-inch  wide  and  long 
enough  to  reach  the  length  of  the  receiver. 
One  end  of  the  strip  is  soldered  into  the 
bolt  on  the  diafram  and  the  other  end  of 
the  strip  is  soldered  into  the  head  of  a 
brass  bolt  that  passes  thru  the  hole  in 
the  small  end  of  the  receiver  shell.  The 
latter  bolt  is  fitted  with  washers  and  a 
nut  to  adjust  the  tension  on  metal  strip. 

A  hole  is  cut  in  the  side  of  the  receiver 
shell  large  enough  to  pass  the  magnets  as 
shown.  If  the  device  is  to  be  used  with 
an  amplifier  the  magnets  shown  have  a  low 
resistance  of  about  20  ohms.  When  used 
in  place  of  the  regular  receivers  they  may 
be  taken  from  a  thousand  ohm  telephone 
ringer.  The  magnets  are  supported  in  a 
box  and  wired  to  two  binding-posts. 

The  pole  pieces  of  the  magnets  should 
come  within  l/64th  of  an  inch  of  the  iron 
strip.  In  use  the  apparatus  is  connected 
in  the  circuit  in  the  usual  manner.  The 
thumb  nut  at  the  small  end  of  the  re- 
ceiver is  turned  till  the  strip  is  just  taut. 


ANOTHER  PENCIL  RHEOSTAT. 

The  accompanying  drawing  shows  a  very 
simple  pencil  rheostat.  It  is  simply  a  com- 
mon "clutch"  pencil  as  sold  anywhere  for 
ten  cents,  and  no  work  is  necessary  to 
convert  it  into  a  rheostat — just  the  con- 


lead. 

^  terminal 
© 

ferm/na/\ 

If  You  Carry  a  Metal  Magazine  Pencil  You 
Are  a  Potential  Electrician.    Connect  a  Wire 
to  the  Case  and  Lead,  and  Prestol  You  Have 
An  Adjustable  Rheostat. 

nection  that  is  all.    To  vary  the  resistance 
it  is  only  necessary  to  slide  lead  in  or  out 
of  the  pencil  case. 
Contributed  by     G.  SCHOENDUVE. 

When  the  signals  come  in  it  is  only  neces- 
sary to  turn  the  nut  and  adjust  the  ten- 
sion on  the  strip  till  it  is  in  resonance 
with  the  note  of  the  signals,  which  point 
will  be  indicated  by  the  loudest  tone. 

When  high-resistance  magnets  are  used 
and  the  instrument  is  connected  direct  to 
the  circuit  without  an  amplifier  it  will  be 
found  advisable  to  use  a  mica  diafram  and 
a  steel  piano  wire  instead  of  the  metal 
diafram   and   the   iron  strip. 

Contributed  by     THOS.  W.  BENSON. 


AUXILIARY  BATTERY  POWER 
FOR  WINDOW  TAPPER. 

When  a  window  tapper  is  running  for  a 
long  period,  the  dry  batteries  run  down, 
causing  the  tapper  to  stop.  In  order  that 
it  may  work  again  the  batteries  must  be 
disconnected  until  they  regain  their  full 
strength.  Using  the  method  shown  here 
the  tapper  can  be  used  continually  without 
a  stop. 


SPDT.SW 
A"  P 


Bat- 


Windoiv  topper 


© 


To  Prevent  Paralyzing  One  Set  of  Batteries 
When  Operating  a  Window  Tapper,  Use  Two 
Sets   Alternately   with   This  Circuit. 

The  S.P.D.T.  switch  blade  is  in  contact 
at  "B,"  making  a  circuit.  When  the  power 
is  exhausted,  it  is  thrown  to  "A,"  putting 
a  new  set  of  batteries  in  the  circuit;  while 
the  others   at   "B"  will   be  recuperating. 

Contributed  by     FRANK  HARAZIM. 


October,  1917 


THE  ELECTRICAL  EXPERIMENTER 


403 


SECRET  DOOR  LOCK  AND  ALARM- 

The  illustration  is  of  an  electric  door 
lock  and  bell  alarm  for  the  front  door  of 
a  home,  garage  or  shop,  which  is  easily 
made  and  installed  in  a  very  short  time. 


The  Electric  Puzzle  Lock  Shown  Acts  As  Its  Own  Thief  Alarm. 
The   Uninitiated   Will   Invariably  Short-Circult  the  "Alarm" 
Contact  Points  Instead  of  the  "Lock"  Circuit  Contacts. 


It  consists  of  a  half-inch  quartered  oak 
board  large  enough  for  the  initials,  which 
are  made  by  driving  brass  upholsterer's 
tacks  in  the  board.  On  the  under  side  of 
board  wires  are  connected  to  the  tacks  as 
per  diagram  and  should  be  soldered  to  the 
points.  An  ordinary  electric  bell  and  a 
bell-ringing  transformer  or  dry  batteries 
are  connected  according  to  illustration  and 
it  is  then  ready  for  use.  The  heavy  lines 
indicate  the  circuit  which  operates  the  lock. 
A  finger  ring  or  any  small  piece  of  metal 
placed  in  contact  with  the  two  tacks  on 
F  and  W  will  operate  the  lock  and  open 
the  door.  Anyone  tampering  with  or  not 
knowing  the  secret  of  the  lock  will  cause 
the  bell  to  ring,  as  the  diagram  will  show. 
A  push  button  connected  to  the  lock  cir- 
cuit and  located  at  a  convenient  point  in- 
side will  be  found  very  handy.  A  low- 
voltage  lamp  can  also  be  placed  in  the  cir- 
cuit and  will  serve  to  light  up  the  entrance. 
This  device  has  given  excellent  service  for 
a  long  time  and  is  still  in  fine  condition. 
Contributed  by  JOHN  F.  WALLACE. 


it  would  be  essential  that  the  supply  of 
current  is  always  on  the  line.  If  one  of 
the  fuses  (K)  should  blow  out  the  line 
would  be  dead,  and  unless  the  operator 
was  on  the  scene  it  might  cause  serious 
damage. 

With  this  apparatus  he 
can  be  in  his  office  and  will 
be  notified  by  the  bell  that 
the  line  is  dead.  The  ex- 
planation of  this  device  is 
as  follows: 

The  current  passes  in 
thru  the  resistance  (B) 
which  amount  depends  up- 
on the  voltage  and  the  cur- 
rent in  the  line ;  this  can 
be  easily  calculated  by 
applying  Ohm's  law.  The 
current  continues  to  flow 
thru  the  magnet  (E)  back 
to  the  line ;  thus  the  cur- 
rent passing  thru  the  coil 
will  energize  it,  and  will 
hold  the  armature  down. 
In  case  the  voltage  goes 
off  the  line  the  coil  (E) 
ceases  to  be  magnetized, 
and  the  armature  is  pulled 
away  from  the  coils,  by 
spring  (H)  —  (which  has 
a  tendency  to  pull  the  armature  away  from 
the  coils)  and  a  local  circuit  is  made  at 


quantity  of  potassium.  If  a  little  mercury 
be  added,  and  the  whole  well  shaken,  it  will 
take  fire  and  burn  vividly. 

The  White  and  Black  Statue :  Construct 
a  small  figure  or  statue  of  white  paper  or 
cardboard,  and  moisten  it  with  a  solution 
of  lead  acetat.  Expose  it  to  fumes  of 
sulfuretted  hydrogen,  and  it  will  turn  black. 

The  Kettle  that  Boils  on  Ice :  Set  a  small 
water  kettle  on  a  piece  of  ice,  now  put  a 
small  amount  of  liquid  carbon  dioxid  into 
the  kettle.    The  contents  will  boil  violently. 

The  Blushing  Picture:  If  any  plain  print 
or  drawing  be  taken  (preferably  one  of  a 
young  lady)  and  the  face,  hands  and  neck 
be  painted  with  a  solution  of  equal  parts 
of  water  and  methylated  alcohol,  to  which 
a  few  grains  of  phenolphthalein  have  been 
added,  on  subjecting  the  picture  to  the  in- 
fluence of  ammonia  vapor  it  will  "blush" 
most  vividly.  Contributed  by 

ELLIOTT  S.  BUCHANAN. 


KEEP  YOUR  BATTERIES  WARM. 

Both  primary  and  secondary  or  storage 
batteries  (accumulators)  are  affected  by 
temperature.  A  battery  that  gives  no 
trouble  in  an  ordinarily  warm  room  shows 
a  falling  off  in  the  output  of  current  if 
exposed  to  a  very  low  temperature.  This 
is  due  to  the  fact  that  the  internal  re- 
ristance  decreases  as  the  temperature  rises, 
within  certain  limits.  Storage  batteries 
have  been  found  to  develop  a  maximum 
efficiency  at  temperatures  approaching  50° 
C.  If  the  temperature  is  much  above  or 
below  this  figure,  the  output  of  current 
falls  off.  Since  the  ordinary  temperatures 
of  a  room  at  any  time  of  the  year  is  gen- 
erally between  12°  and  20°  C.  it  will 
be  seen  that  most  storage  batteries  are 
not  given  an  opportunity  to  deliver  the 
maximum  ;tmount  of  energy  of  which  they 
are  capable. 

Contributed  by  H.  J.  GRAY. 


When    the    Line    Voltage    Fails    the  Relay 
Closes  an  Alarm  Bell  Circuit,  the  Bell  Being 
Placed  At  Any  Point  Desired. 

contact  (I),  which 
in  turn  is  in  series 
with  a  battery  and 
bell,  as  shown.  A, 
is  a  rubber  con- 
tact to  prevent 
cross  -  connections. 

Besides  this  use 
of  the  indicator  it 
can  be  put  to  many 
other  advantageous 
uses  as  the  opera- 
tor sees  fit. 

Contributed  by 
H.  E.  BEANE. 


UNIQUE  GLYCERIN  SWITCH 
MADE  FROM  SOUNDER. 

It  is  often  necessary  to  break  a  circuit 
at  relay  contact  points,  where  the  circuit 
to  be  broken  carries  current  at  110  volts. 
The  arcing  is  intense  when  the  current  is 
much  above  1  ampere.  A  simple  and  very 
effective  oil  switch  may  be  made  from  ma- 
terial which  is  almost  always  on  hand. 

Secure  a  brass  base  from  an  Edison 
lamp  (one  may  be  removed  from  a  lamp 
by  heating  the  glass  near  the  base  in  a 
Bunsen  flame).  Drill  a  hole  in  the  bottom 
of  it  for  a  bolt  to  pass  thru.  Screw  the 
socket  onto  the  end  of  the  armature  of  a 
telegraph  sounder  which  will  serve  as  the 
relay.  Before  putting  the  bolt  thru  the 
socket,  slip  a  soft  rubber  or  fiber  wa_sher 
on  to  prevent  any  leaking  of  oil  thru  the  hole. 

A  standard  which  serves  as  the  rear  con- 
tact may  be  made  from  an  ordinary  fixture 
crow-foot,  a  piece  of  gas  pipe  and  a  piece 
of  3/32"  brass  or  steel  which  is  threaded 
to  receive  an  adjusting  screw.  (See  illus- 
tration.) 

The  writer  had  a  great  deal  of  difficulty 
in  securing  a  suitable  oil  to  kill  the  arc. 
After  trying  sweet  oil,  linseed  oil  and  ma- 
chine oil  he  tried — glycerin.  And  it  does 
the  work.  Arcs  from  breaks  carrying  10 
amperes  were  successfully  quenched  by 
using  glycerin  in  the  cup. 

It  may  be  also  of  interest  to  note  that 
castor  oil  is  quite  as  satisfactory  as  gly- 
cerin, and  a  lot  cheaper  too.    The  cup  may 


TELEGRAPH  RELAY  USED  FOR 
VOLTAGE  INDICATOR. 

Where  an  operator  can  not  watch  his 
voltage  continuously  and  where  a  con- 
stant voltage  is  required,  the  accompanying 
diagram  shows  how  a  telegraph  instru- 
ment can  be  made  into  a  voltage  indicator 
in  a  few  minutes'  time. 

If  a  motor  (J)  was  operating  a  flood 
pump  or  any  other  apparatus  automatically, 


Gas  p/pe 


no  vo 


1  / 

5/ofe  base 


CHEMICAL 
EXPERI- 
MENTS. 

Spontan  e  o  u  s 
Combustion:  A 
mixture  of  potas- 
sium chlorat  and 
flour  at  once  takes 

fire    on    being    For  Breaking  Heavy  Currents  the  Arc  Is  Best  Broken  in  Glycerin.  The 
touched  with  a 
drop    of  sulfuric 
acid. 

The  Spontaneous  Combustion  of  Three     be  partially  filled  with  mercury  with  the 
Metals:    In  a  perfectly  dry  ladle  place  a     oil  over  the  top  of  it. 
small    piece    of    sodium    with    an    equal        Contributed  by  ALBERT  H.  BEILER. 


Latter  Is  Held  in 


a  Cup,  Operated  by  "Sounder' 
the  Manner  Indicated. 


or  Other  Magnets  in 


404 


THE  ELECTRICAL  EXPERIMENTER 


October,  1917 


Under  this  heading  we  publish  every  month 
useful  information  in  Mechanics,  Electricity 
and  Chemistry.  We  shall  be  pleased,  of 
course,  to  have  our  readers  send  us  any 
recipes,  formulas,  wrinkles,  new  ideas,  etc., 
useful  to  the  experimenter,  which  will  be 
duly  paid  for,  upon  publication,  if  acceptable. 


FOR    CLEANING  VARIOUS 
SUBSTANCES. 

Alabaster. — Use  strong  soap  and  water. 

Black  Silk. — Brush  and  wipe  it  thoroly, 
lay  on  table  with  side  intended  to  show, 
up ;  sponge  with  hot  coffee  strained  thru 
muslin ;  when  partly  dry,  iron. 

To  Remove  Stains  or  Grease  from  Oil 
Paint. — Use  bisulfid  of  carbon,  spirits  of 
turpentine,  or  if  dry  and  old,  use  chloro- 
form. These  and  tar  spots  can  be  softened 
with  olive  oil  and  lard. 

Stains,  Iron  Rust,  or  Ink  from  Vellum 
or  Parchment. — Moisten  the  spot  with  a 
solution  of  oxalic  acid.  Absorb  same  quick- 
ly by  blotting  paper  or  cloth. 

Rust  from  Steel. — Take  half  ounce  of 
emery  powder  with  one  ounce  of  soap  and 
rub  well. 

Fruit  Spots  from  Cotton. — Apply  cold 
soap,  then  touch  the  spot  with  a  hair  pencil 
or  feather  dipped  in  chlorate  of  soda,  then 
dip  immediately  in  cold  water. 

Grease  from  Silks. — Take  a  lump  of 
magnesia,  rub  it  wet  on  the  spot,  let  it  dry, 
then  brush  the  powder  off. 

Iron  Rust  may  be  removed  from  white 
goods  by  sour  milk. 

Scorch  Stains  from  White  Linen. — Lay 
in  bright  sun. 

Mildew. — Moisten  the  spot  with  clean 
water ;  rub  on  it  a  thick  coating  of  castile 
soap  mixed  with  chalk  scrapings ;  rub  with 
end  of  finger,  then  wash  off. 

Oil  Marks  on  Wall  Paper. — Apply  paste 
of  cold  water  and  pipe  clay,  leave  it  on  all 
night,  brush  off  in  the  morning. 

Paint  Spots  from  Clothing. — Saturate 
with  equal  parts  turpentine  and  spirits  of 
ammonia. 

To  Cleanse  House  Paper. — Rub  with  a 
flannel  cloth  dipt  in  oatmeal. 

Black  Cloth. — Mix  one  part  of  spirits  of 
ammonia  with  three  parts  of  warm  water, 
rub  with  sponge  or  dark  cloth,  clean  with 
water,  rub  with  the  nap. 

Furniture,  for  Finger  Marks. — Rub  with 
a  soft  rag  and  sweet  oil. 

Chromos. — Go  over  lightly  with  a  damp 
linen  cloth. 

Zinc. — Rub  with  a  piece  of  cotton  cloth 
dipt  in  kerosene,  afterwards  with  a  dry 
cloth. 

Hands  from  Vegetable  Stains. — Rub  with 
a  slice  of  raw  potato. 

Window  Glass. — Paint  can  be  removed 
by  a  strong  solution  of  soda. 

To  Clean  Tinware. — Common  soda  ap- 
plied with  a  moistened  newspaper  and  pol- 
ished with  a  dry  piece,  will  make  it  look 
like  new. 


DIRECTIONS  FOR  WHITE  METAL 
PLATING. 
By  Aaron  Van  Citters. 

A  number  of  firms  have  advertised  white 
metal  plating  outfits,  for  plating  knives, 
forks,  spoons,  etc.,  for  which  they  charge 
from  ten  to  twenty  dollars.  By  following 
the  instructions  given  below,  you  can,  with 
the  assistance  of  a  blacksmith  in  making 
the  crucible  and  hood,  set  up  this  outfit 
complete  for  about  two  dollars  and  a  half 
or  less. 

To  make  the  crucible — Take  a  piece  of 
gas-pipe  4x6  inches,  weld  a  bottom  in  it, 
and  a  band  around  the  top  from  which  it 
hangs  inside  the  hood. 

To  make  the  hood — Make  a  flaring  cylin- 
der of  sheet  iron,  the  small  end  the  proper 
size  to  fit  under  the  ring  of  crucible ;  the 
other  end  about  one-fourth  larger  in  di- 
ameter, and  sufficiently  long  to  hold  cru- 
cible upright  with  bottom  just  clear  of 
the  stove  or  gas  plate. 

To  make  the  White  Metal — Pure  tin, 
10  lbs.,  lead  4  ozs.,  antimony  2  ozs.  Melt 
and  mix  thoroly.  A  better  grade  is  made 
by  using  2  ozs.  of  pure  silver  in  place  of 
the  antimony. 

Jar  No.  i  (Pickle  Solution) — For  iron 
or  steel  is  composed  of  muriatic  acid  only. 

Jar  No.  2  (Dip  Bath) — Dissolve  2 
pounds  refined  zinc  in  2  quarts  fluid  hydro: 
chloric  acid  C.  P.  When  dissolved  and 
cold,  add  half  a  teacup  of  clear  rain  water 
or  filtered  water.  (This  is  a  dangerous 
solution  to  mix,  as  it  is  very  violent  when 
the  zinc  is  being  consumed,  and  great  care 
should  be  taken.) 


How    Crucible    Is    Made    for    White  Metal 
Plating. 

Jar  No.  3  (Chill  Bath) — Dissolve  6  ozs. 
di-ammonia  carbonate  in  3  pints  of  filtered 
water.  Use  at  a  temperature  of  120  de- 
gress F. 

Jar  No.  4  (Pickle  Solution) — For  Irish 
silver  and  brass,  dissolve  12  ozs.  granu- 
lated nitratum  in  2  quarts  of  filtered  water ; 
then  add  slowly  2  quarts  commercial  sul- 
furic acid.  (Note — Unless  you  are  going 
to  do  a  great  deal  of  plating,  Jar  No.  4 
is  unnecessary,  as  Jar  No.  1  answers  as 
a  pickle  solution  for  all  metals. 

Stripping  Solution — Is  composed  of  1 
pound  granulated  kali ;  or  potash  and  2 
scruples  of  French  rouge;  dissolved  in  1 
gallon  commercial  sulfuric  acid. 

(The  Flux) — Mix  thoroly  5  lbs.  granu- 
lated white  ammonia  hydrochlorate  with 
4  drams  French  rouge.  For  convenience 
in  using,  put  a  portion  in  an  ordinary  tin 
pepper  box. 

Directions  for  Plating — Place  the  sheet 
iron  hood  on  the  stove  or  gas  plate,  the 
small  end  up,  then  set  the  iron  crucible 
previously  filled  with  the  white  metal,  in- 
side the  hood,  so  edge  will  rest  on  top 
of  same.  But  little  heat  is  required  to 
melt  the  metal,  which  forms  a  thin  metal- 
lic solution.  Care  should  be  taken  not 
to  get  it  too  hot.  If  after  an  article  is 
plated  it  shows  a  yellowish  color,  it  is  be- 
cause of  too  much  heat,  which  should  be 
partly  turned  off.  Proceed  to  plate  as 
follows : 


First,  put  articles  to  be  plated  in  Jar 
No.  1,  allowing  them  to  remain  ten  min- 
utes to  remove  all  rust,  etc.,  then  rinse 
in  clear,  cold  water.  Next  take  one  piece 
at  a  time  and  rinse  in  Jar  No.  2  for  a 
few  seconds ;  then  immerse  the  article 
slowly  in  the  crucible  containing  the  melted 
metal ;  raise  slowly  up  and  down  once  or 
twice,  sprinkle  a  little  flux  on  the  article, 
letting  some  of  the  flux  fall  on  the  melted 
metal.  Then  draw  article  from  crucible 
and  immerse  slowly  into  Jar  No.  3,  which 
hardens  the  plate,  after  which  rinse  in 
clear  water  and  it  is  finished. 

Knives,  forks  and  spoons  should  be 
plated,  one-half  at  a  time;  then  the  oper- 
ation reversed.  About  one  minute  is  re- 
quired to  plate  a  single  article.  A  little 
practise  will  make  you  perfectly  familiar 
with  plating  in  this  manner,  and  you  will 
be  able  to  see  at  a  glance  when  everything 
is  perfect.  When  there  is  much  old  plate 
on  an  article,  place  stripping  solution  in  a 
crock,  heat  it,  and  immerse  article  therein 
until  the  old  plate  is  all  removed ;  then 
rinse  in  clear  water,  dry  with  a  chamois 
skin,  and  proceed  to  plate  as  above. 

(Special  Note) — When  much  old  plate 
is  removed  by  stripping,  it  pays  to  reclaim 
the  silver,  which  may  be  done  in  the  fol- 
lowing manner :  Add  common  salt  to  the 
stripping  solution  as  long  as  it  throws 
down  a  precipitate,  then  pour  off  the  solu- 
tion. Wash  the  precipitate  with  clear 
water,  then  add  a  few  small  pieces  of  sheet 
zinc  to  it  and  let  stand  until  the  preciptate 
turns  to  a  black  powder,  which  will  take 
several  hours.  ■  Then  wash  the  powder 
several  times  in  warm  water,  dry  between 
sheets  of  blotting  paper,  and  pick  out  the 
pieces  of  zinc.  The  powder  will  be  pure 
silver  which  you  can  melt  and  run  into 
bars. 


VALUABLE    HINTS    FOR  PHOTO 
WORKERS. 

Bottles. — Better  to  send  the  unknown 
contents  of  a  bottle  down  the  sink  than 
risk  spoiling  a  formula  with  it.  Do  not 
wait  for  labels  to  drop  off ;  give  the  lot 
an  inspection  every  three  or  six  months, 
and  replace  any  which  are  becoming  illeg- 
ible, says  the  Am.  Photog's  Weekly. 
Don't  wait  till  this  has  happened. 

Labels  on  Bottles  Containing  Solu- 
tion.— Place  the  label  in  such  a  position 
that  you  can  indicate  by  an  arrow  point 
on  the  label  just  how  far  up  in  the  bottle 
the  stock  solution  comes  when  making  up 
a  fresh  lot. 

Waste  Box.— Do  not  throw  spent- 
matches,  plate-box  wrappers,  bits  of  string, 
or  anything  else  (not  even  cigarette  ends) 
on  the  floor,  but  in  the  waste  box  (a  large- 
size  biscuit  tin  is  just  the  size  and  shape). 
Everything  on  the  floor  makes  for  dust. 

Seconds  Pendulum. — A  little  over  a 
yard  of  fire  string,  the  bob  of  an  old 
clock,  a  long  bit  of  brass  chain.  This 
clinks  against  the  rim  of  a  half-pound 
tobacco-box  lid  every  second  swing.  The 
pendulum  hangs  from  a  nail  in  the  wall. 
The  pendulum  is  forty  inches  long. 

Cotton-Batting  Bottle.  —  This  bottle 
contained  caustic  potash  solution.  The 
stopper  being  fixt  resisted  "firmly  but 
gently"  every  persuasive  invitation  to  move 
it.  It  was  tapt  off  at  the  neck.  The 
shoulder  of  the  bottle  was  cut  with  a  file 
scratch  and  hot  wire.  The  sharp  edge 
taken  off  with  a  hard  pebble.  It  now  stands 
on  the  sink  shelf,  and  holds  cotton  batting 
with  which  to  swab  the  surface  of  a  nega- 
tive or  use  as  a  quick  filter. 

Toothbrush  Bone  Handle. — Filed  down 
to  make  a  finger-nail  shaped  end,  which 
acts  admirably  as  a  plate  lifter. 


October,  1917 


THE  ELECTRICAL  EXPERIMENTER 


405 


Experimental  Chemistry 


By  ALBERT  W.  WILSDON 
Seventeenth  Lesson 


Ammonia  (NHL)  and  Ammonium  Hydroxid 
(NH4OH) 

HISTORY: 


T 


of 


HE  aqueous  solution  of  ammonia 
gas  and  some  of  its  salts,  as  am- 
monium chlorid,  or  sal-ammoniac, 
were  known  to  the  early  alchemists, 
and  described  by  them  as  "Spirits 
Hartshorn."     Basil   Valentine   in  the 


Fig.  84.    Apparatus  Set  Up  for  the  Prepara- 
tion of  Ammonium  Hydroxid— N  H4OH. 


fifteenth  century  showed  that  the  gas  could 
be  made  as  we  make  it  to-day ;  namely, 
from  ammonium  chlorid  (NH4C1).  Priest- 
ley in  1747  was  the  first  to  prepare  gaseous 
ammonia,  by  heating  together  sal-ammoniac 
(Ammonium  chlorid),  and  lime,  and  col- 


lecting the  gas  over  mercury.  He  called  it 
"Alkaline  Air"  which  was  later  changed  to 
"Volatile  Alkali." 

Berthollet  in  1785  showed  that  it  is  com- 
posed of  Nitrogen  (N)  and  Hydrogen 
(H),  and  Davy  in  1800  made  the  volumet- 
ric determination  necessary  for  the  symbol. 

Occurrence  and  Formation  : 

Ammonia  is  found  free  in  small  quantity 
only.  A  very  minute  quantity  is  formed  in 
combination  with  carbonic,  nitric  and 
nitrous  acids,  during  electrical  discharges 
in  the  air,  from  the  hydrogen  of  ,  water, 
and  nitrogen  of  the  air.  This  often  com- 
bines with  an  oxid  of  nitrogen  (formed 
by  the  same  process)  to  make  ammonium 
nitrat  (NH,  NOs),  _  and  the  product  is 
finally  washed  by  rain  into  the  earth. 

It  is  also  found  as  sulfate  and  chlorid 
near  active  volcanoes,  having  been  pro- 
duced by  the  hot  lava  flowing  over  fertile 
soil  containing  nitrogen.  Ammonia  and 
its  salts  are  formed  in  the  distillation  of 
many  organic  substances  as  bones,  and 
other  animal  tissues  and  excretions,  as  well 
as  the  putrefaction  of  nitrogenous  organic 
substances. 

Formerly  horns,  hoofs,  and  other  animal 
products  were  distilled,  and  ammonium 
carbonat  thus  produced  neutralized  with 
hydrochloric  acid,  the  product  after  sub- 
limation being  known  as  sal-ammoniac 
(ammonium  chlorid).  At  the  present  time 
coal  is  used  and  the  supply  obtained  by  a 
similar  process. 

Preparation  : 

1.  Thru  the  union  of  its  elements  by 
means  of  the  silent  electric  discharge. 

2.  Thru  the  reduction  of  the  various  com- 
pounds of  nitrogen  and  oxygen  or  their 
acids. 


N,Oi    +     5H2  - 

Nitrogen   Dioxid  Hydrogen 


2  NH3  +  2  H20 
Ammonia  Water 


Fig.  85.    Necessary  Apparatus  for  the  Col- 
lection of  Ammonia — NH3 — by  Upward  Dis- 
placement. 


3.  Thru  solution  of  many  metals  in  Nitric 
acid. 

HN03   +   4H,  =    3  H,0  +NH3 
(4  Zn  +  9  HN03  =  4  Zn(N03)2  +  NH3  +  3  H20) 

4.  By  the  reduction  of  nitrats  or  nitrits 
by  nascent  hydrogen  in  alkaline  solution. 

NaNO,  +  3  Ho  =  NaOH  +  H„0  +  NH3 
8A1  +  5  KOH  +  3HN03  =  2  H20  +  8KA10-, 
+  3NH3  Potassium 
Aluminat 

5.  Ammonia  gas  is  prepared  on  a  large 
scale  by  heating  together  calcium  hy- 
droxid  and  ammonium  sulfate  or  chlorid. 

(NH4)oS04  +  Ca(OH)..  =  CaS04  +  2NH3 
+    2  H20 

6.  For  laboratory  purposes  it  is  prefer- 
able to  heat  the  solutions  of  ammonia. 

7.  The  hydroxid  is  prepared  by  the  ac- 
tion of  a  strong  base  or  one  of  its  salts. 
The  chief  salts  are  ammonium  chlorid 
(NH4C1)  ;  ammonium  nitrat  (Nri4N03)  ; 
ammonium  sulfate  (  (NH4)2S04)  and  am- 
monium carbonat  (  (NH4)2C03).  By  mix- 
ing any  one  of  these  with  either  calcium, 
potassium  or  sodium  hydroxid,  and  apply- 
ing gentle  heat,  there  are  formed  am- 
monium hydroxid  (NH4OH)  and  ammonia 
(NH3).  These  reactions  come  under 
Barthollct's  law  of  gases.  Sal-ammoniac 
(NH4C1)  and  slaked  lime  (Ca(OH)2),  be- 
cause of  their  cheapness,  are  usually  em- 
ployed. 

2NH4CI    +    Ca(OH)2  =  CaCl2     -f  2NH4OH 
Ammonium        Calcium        Calcium  Ammonium 
Chlorid         Hydroxid      Chlorid  Hydroxid 
(Slaked  lime) 


It  should  be  remembered  that  the  hy- 
droxid is  only  the  gas  combined  with  water, 
and  two  substances,  ammonium  hydroxid 
(NH4OH)  and  ammonia  (NHs)  are  both 
called  "ammonia",  but  not  accurately  so. 
Whenever  one  of  them  is  found  the  other 
usually  exists,  as  Ammonium  hydroxid 
gives  off  the  gas  and  ammonia  takes  up 
water. 


Fig.  86.  Simple  Apparatus  Required  in  Per- 
forming the  "Ammonia  Fountain"  Experi- 
ment.   It  Is  Shown  Here  in  Acual  Operation. 


When  required  pure,  the  gas  must  be  past 
over  calcium  oxid  (quicklime)  to  remove 
the  moisture,  and  then  collected  over: 
mercury. 

{Continued  on  page  427) 


Fig.  87.  Apparatus  for  Illustrating  Diffusion 
and  Absorption  of  NH3.  Left  Hand  Flask 
Contains  N  H4OH  ;  Right  Hand  Flask— Water. 


406 


THE  ELECTRICAL  EXPERIMENTER 


October,  1917 


Our  Amateur  Laboratory  Contest  is  open  to  all  readers,  whether  subscribers  or  not.  The  photos  are  judged  for  best  arrangement  and  efficiency 
of  the  apparatus.  To  increase  the  interest  of  this  department  we  make  it  a  rule  not  to  publish  photos  of  apparatus  unaccompanied  by  that  of  the  owner.  Dark 
photos  preferred  to  light  toned  ones.  We  pay  each  month  $3.00  prize  for  the  best  photo.  Make  your  description  brief  and  use  only  one  side  of  the  sheet. 
Address  the  Editor,  "With  the  Amateurs"  Dept. 


At  Last  an  "Electrical  Laboratory"  Photo!!! 

Well,  "Radio-bugs,"  you  have  got  to  take  off  your  hat  to  Mark  Slabodnik,  of  Ely,  Minnesota,  winner  of  this  month's 
prize,  and  mark  you,  the  ONLY  prize  awarded  this  month  in  "With  the  Amateurs'  Department."  Now,  why  is  it  that  we 
can't  receive  more  photos  from  "ELECTRICAL  LABORATORY"  owners,  when  there  are  about  a  million  of  you  scattered 
thruout  the  United  States  at  this  very  moment !  As  you  will  remember  we  made  all  of  you  a  special  offer  in  the  September 
number,  viz.,  we  offered  to  give  not  only  the  $3.00  monthly  prize  for  the  best  "Electrical  Lab."  photo,  but  5  (five!!!)  addi- 
tional prizes  of  one  year's  subscription  to  this  journal,  and  a  copy  of  the  "EXPERIMENTAL  ELECTRICITY  COURSE" 
for  the  best  five  photos  submitted,  after  awarding  the  first  prize.  But  nary  a  peep  from  a  blessed  mother's  son  of  you.  Now 
it  is  up  to  you  to  get  busy  at  once,  and  photograph  that  "Electrical  Lab."  We  mean  every  word  of  it,  "Bugs"!  For  if  you 
do  not,  this  department  is  simply  going  to  slide  into  oblivion.  As  we  have  just  said,  it  is  strictly  up  to  you  whether  you 
wish  to  take  a  chance  on  winning  the  $3.00  cash  prize,  and  also  if  you  wish  to  throw  away  the  chance  of  receiving  "The 
ELECTRICAL  EXPERIMENTER"  magazine  for  one  year  free  of  all  cost,  besides  the  copy  of  the  Experimental  Electricity 
Course,  which  is  worth  $1.00  alone  to  any  electrical  student.    Address  the  Editor  "With  The  Amateur's  Prize  Contest." 


A  GROUP  OF  REPRESENTATIVE  AMERICAN  AMATEUR  RADIO  STATIONS. 


Electrical  Laboratory  of,  1— Mark  Slabodnik,  Ely,  Minn.  (Prize  Winner);  Radio  Stations  of,  2— G.  Eddie  Johnson,  Toledo,  O.;  3— Nicholas  L. 
Googin,  Jr.,  Cazenovia,  N.  Y.;  A — Armin  Vogt,  Jansen,  Nebr.;  5 — Steddom  Bros.,  Oklahoma  City,  Okla.;  6 — Warren  Benson,  Brooklyn,  N.  Y. 


October,  1917 


THE  ELECTRICAL  EXPERIMENTER 

That  "Perpetual  Motion 


407 


yy 


WE  HAVE  never  publisht  a  prize 
contest  that  came  within  miles 
of  being  such  a  hilarious  success 
as  our  "Scenic  Railroad"  hoax. 
When  we  publisht  it,  we  did  it 
more  in  order  to  show  how  young  boys  are 
often  misled,  due  to  incomplete  knowledge, 
rather  than  our  exploiting  a  scientific  im- 
possibility. In  other  words,  the  whole 
thing  simply  was  a  joke. 

Imagine  then  our  genuine  surprise  when 
immediately  after  publication,  hundreds 
upon  hundreds,  nay 
thousands  of  letters 
poured  in  upon  us, 
telling  us  why  the 
scheme  would  not  or 
really  would  work ! 
Up  to  this  time  of 
writing  2,109  letters 
were  received !  Imag- 
ine such  a  thing — and 
they  still  come  and 
come,  and  we  have  as 
yet  to  hear  from  for- 
eign  countries ! ! 

The  amount  of  good 
people  who  took  the 
thing  really  serious  is 
little  short  of  astound- 
ing. And  hundreds 
really  imagined  it 
worked !  Even  the 
gentle  sex  wrote  four 
letters ! 

Hundreds  of  letters 
were  alike,  most  of 
their  writers  consider- 
ing   "friction"  only. 

But  the  greatest  bone  of  contention  was  the 
dynamo-motor  point.  Almost  a  thousand 
correspondents  contended  that  when  feed- 
ing the  storage  battery  current  back 
into  the  dynamo,  the  latter  would  reverse 
thus  making  the  car  go  backward !  These 
good  people  evidently  never  heard  of  an 
automatic  reversing  switch,  nor  did  they 
stop  to  think  that  the  great  Chicago,  Mil- 
waukee and  St.  Paul  Railroad  actually 
works  on  this  principle,  where  the  coast- 
ing trains  pump  energy  back  into  the  line. 
Of  course,  this  is  not  perpetual  motion, 
nor  anything  near  it,  it  is  simply  efficiency. 

Only  one  letter,  Mr.  L.  J.  Bair's,  men- 
tioned this  fact,  hence  the  award  of  the 
"first  prize"  to  him.  Several  other  good 
letters  are  also  publisht  and  prizes  were 
awarded  to  the  writers. 

Scores  of  correspondents  turned  uncon- 
scious humorists,  and  we  are  printing  a 
few  choice  samples  selected  at  random.  We 
are  genuinely  sorry  that  we  have  not  the 
space  to  publish  several  hundred  more  of 
them ! 


using  the  regenerative  apparatus,  no  such  momen- 
tum will  be  attained  as  tne  speed  of  the  car  will 
be  reduced  in  direct  proportion  to  the  amount  of 
current  generated. 

LEIGH  J.  BAIR, 
111  West  111th  Street, 

New  York  City. 


drawn  from  the  storage  battery  and,  owing  to  the 
losses  in  the  machinery,  more  power  would  be  con- 
sumed than  was  generated. 

WILLIAM   C.  BELLER, 

51   East  123d  St., 
New  York  City. 


"E  E' 


Honorable  Mention  and  Subscription  to 
100   Words — Count  'Em 

The  air  resistance,  friction  of  bearings,  brush  on 
third  rail  and  magnetic  drag  on  armature  reduce 
speed  in  descending  hill  so  that  the  momentum  of 
car  will  not  ascend  a  hill  equal  in  height  to  its 
starting  point,  consequently  in  order  to  have  the 
car  travel  nearly  around  the  ring,  each  succeeding 


Is  He  Joshing  Us? 

The  Scenic  Railway  idea  would  be  fine  but  for  a 
few  obstructions. 

The  energy  loss  due  to  the  friction  between  the 
flange  of  the  wheels  and  the  rails  is  hardly  worth 
mentioning.  The  voltage  drop  in  the  iron  rails  is 
small.  Some  energy  is  also  lost  in  overcoming  the 
air  pressure  on  the  front  of  the  car. 

Much  energy  is  wasted  in  starting  and  stopping. 

This  could  be  prevent- 
ed, however,  if  the  pas- 
sengers would  jump  on 
and  off  while  the  car  is 
in  motion. 

Not  counting  these  few 
hindrances  the  idea  is 
fine  and  it  ought  to  be 
patented. 

C.  M.  HOLLENBACH, 

Saegersville,  Pa. 


In  Our  "August"  Number  We  Publisht  This"Perpetual  Motion"  Scenic  Railway  Problem. 
The  Large  Storage  Battery  Was  Supposed  to  Supply  Current  to  the  Ascending  Cars;  the 
Descending  Cars  Pumped  "Juice"  Back  Into  the  Battery,  etc.,  ad  infinitum.  Here  Are 
Some  of  the  Answers  We  Received.    The  Editor's  Chair  Is  Still  Oscillating  From  the  Shock. 

hill  must  be  less  in  height.    Therefore  car  will  stop 
some  distance  below  its  starting  point. 

Assuming  efficiency  of  dynamo,  storage  battery 
and  motor  80  per  cent  each,  then  about  51  per  cent 
of  energy  lost  is  returned  to  it  as  motive  power. 
Therefore,  would  come  nearer  performing  feat  with- 
out  dynamo  attached. 

C.    F.  RUDOLPH. 


Collisions  and  Wrecks! 
Wow,  What  a  Head- 
ache!!! 

The  "Perpetual  Motion 
Device"  won't  work  be- 
cause when  the  dynamo 
operates  as  a  motor  it 
will  run  the  car  back- 
wards, which  would  col- 
lide with  the  other  cars. 
Also  while  ascending  cars 
are  using  current,  the 
descending  cars  are  send- 
ing current  in  the  oppo- 
site direction  to  charge 
batteries.  Thus  there 
would  be  two  electrical 
currents  tending  to  go  in 
opposite  directions  in  the 
same  conductor,  and  that 
is  impossible,  as  each 
would  tend  to  stop  the 
other. 
H.  KERSTETTER, 
633  Carlton  Street, 

Toledo,  Ohio. 


First  Prize  and  Subscription  to  "E  E" 

As  an  answer  to  your  Perpetual  Motion  Scenic 
Railway  Puzzle,  I  wish  to  offer  the  following  for 
your  consideration: 

The  facts  resolve  down  to  the  following  condi- 
tions: We  have  a  weight  mounted  at  a  height,  and 
in  falling  or  rolling  from  this  height,  it  attains  a 
certain  amount  of  kinetic  energy  m  foot  pounds. 
It  requires  exactly  the  same  amount  of  energy  in 
foot  pounds  to  elevate  this  weight  to  the  same 
height  as  is  generated  by  falling. 

From  these  facts,  it  is  self-evident  that  were  all 
apparatus  and  processes  of  this  transfer  of  energy 
one  hundred  percent  efficient,  the  system  described 
would  be  O.  K.,  but  it  is  also  evident  thnt,  due 
to  wind  friction  and  bearing  friction  on  the  cars, 
and  copper,  iron,  windage  bearing  and  brush  losses, 
of  the  generating  apparatus  and  motor  equipment, 
it  will  be  only  about  60  per  cent  efficient  at  its 
best.  This  efficiency  is  attained  by  the  regenerative 
apparatus  used  on  "the  Chicago,  Milwaukee  and  St. 
Paul  R.  R.  on  a  three  phase  electric  system  over 
the  Rocky  Mountains. 

The  misleading  feature  of  this  perpetual  motion 
scheme  is  that,  due  to  the  momentum  of  the  car  on 
the  downward  slide,  it  would  reach  to  a  high  point 
on  the  upward  grade  and  requires  only  a  little 
effort  to  carry  it   over   the  top  peak,  but  when 


Honorable  Mention  and  Subscription  to  "E  E" 

The  fallacy  of  the  idea  may  be  shown  in  the 
clearest  way  by  a  simple  mathematical  process.  In 
this  solution  the  loss  of  energy  thru  friction,  dyna- 
mo inefficiency  and  electrical  resistance  is  disre- 
garded, altho,  of  course,  this  would  be  great  enough 
to  make  the  idea  impractical. 

It  may  be  asssumed  that  the  energy  required  to 
drive  the  car  from  the  point  B  to  C  would  be 
equal  to  the  energy  obtained  from  the  car  traveling 
from  A  to  B.    Let  these  amounts  equal  x  and  x1. 

Then 

x  =  x1 

Also  let  the  kinetic  energy  =  K  and  the  electrical 
energy  =  E. 

Now  in  traveling  from  A  to  B,  kinetic  energy  K 
will  be  obtained  minus  the  electrical  energy  used 
to  charge  the  storage  batteries,  or 

K  —  E  =  x. 
Now  from  B 
to  Ct  the  energy 
required  will  be 
the  kinetic  K, 
which  will  carry 
the  car  to  some 
point  C1,  plus 
the  electrical, 
from  C1  to  C,  or 

K  +  E  =  x1 
and  since 

x  =  xl 

K  —  E  =  x 

K  +  E  =  x1 
th  en 


"Closed  Circuit" — Bless  Its  Heart!! 

The  Scenic  Railway  cannot  operate  perpetually, 
because  the  dynamo-motor  is  connected  to  a  closed 
circuit.  To  operate  a  circuit  of  this  kind  a  dynamo 
must  have  sufficient  power  applied  to  it.  Thus, 
when  descending  a  hill,  the  energy  required  by  the 
dynamo  checks  the  speed  of  the  car  so  that  after  a 
few  descents  the  car  must  stop  altogether. 

PAUL  R.  GROVE, 
714  Moore  Street, 
Huntington,  Pa. 


A 

8 

1 

J 

E  =  K  +  E 

Eureka!     It  Works!     Oil!!     (Castor  Oil?) 

The  reason  why  this  device  will  not  work  is  this: 
Tho  the  energy  generated  by  the  descending  car 
would  be  sufficient  to  carry  up  a  similar  hill  a 
similar  car  some  of  the  energy  is  wasted  in  heat 
by  friction.  Altho  by  oiling  this  could  be  reduced, 
it  could  not  be  eliminated.  Then  some  current 
would  be  wasted  in  heating  the  wires.  If  there 
were  fewer  cars  or  fewer  people  on  the  next  trip 
it  might  work.  But  it  would  die  down  in  a  short 
time  unless  power  were  supplied  from  an  outside 
source. 

JOHN  A.  McGUIRE, 

39   Hope  Street, 
Ridgewood,  N.  J. 


Quick — Call  an  Ambulant  !! 

The  car  in  going  down-hill  would  generate  a  cur- 
rent that  would,  at  the  bottom  of  the  incline,  tend 
to  drive  the  car  back  up  again,  and  it  would  back 
it  up  a  little  way,  the  car  only  to  come  to  rest  at 
last  at  the  bottom. 

LESTER  WOLF, 
920  S.  11th  Street, 
South  Bend,  Ind. 


which,  of  course. 


is  impossible. 
JOHN  R. 
333  E. 


MARTIN, 
Morton  Ave., 
Jacksonville,  111. 


Honorable  Mention  and  Subscription  to  "E  E" 

In  explanation  of  the  inoperativeness  of  the  Per- 
petual Motion  Scenic  Railway,  described  on  page 
249  of  the  August  number  of  your  magazine,  I 
would  state  the  following:  It  is  well  known  that  a 
dynamo  consumes  mechanical  energy  in  proportion 
as  it  produces  electrical  energy.  Therefore,  the 
power  required  to  drive  the  dynamo  would  so  re- 
tard the  descent  of  the  car  on  the  down-grades  that, 
having  less  momentum,  additional  power  would  be 
required  to  lift  it  on  the  up-grades.    This  would  be 


Everett  Has  the  Right  Dope! 

A  car  would  climb  just  as  far  up  the  last  peak 
without  the  addition  of_  a  generator  and  storage  bat- 
tery plant  as  with  it,  since  its  momentum  would  be 
impeded  by  the  running  of  the  generator,  as  by 
the  well-known  law:  The  current  generated  in  a 
conductor  by  its  motion  in  a  magnetic  field  flows  in 
such  a  direction  that  its  magnetic  field  tends  to 
prevent  the  motion.  In  other  words,  the  amount  of 
energy  used  up  by  the-  running  of  the  generator 
is  greater  than  that  gained  by  the  motor,  the  loss 
being  due  to  resistance,  friction  in  the  generator 
and  motcr,  etc. 

EVERETT  L.  SWEET, 

145  Congress  Ave., 
Providence,  R.  I. 


This  Bird  Claims  It  Will  Run  40  Seconds!! 

It  is  impossible  for  your  "Perpetual  Motion 
Scenic  Railway"  to  work  for  several  reasons: 

Regardless  of  what  height  the  grades  are  upon 
which  the  cars  descend,  the  dynamo-motor  would 

{Continued  on  page  430) 


408 


THE  ELECTRICAL  EXPERIMENTER 


October,  1917 


PATENTS 


Illuminated  Torpedo 

(No.  1,232,671;  issued  to  Alphonse 
Ferandez.) 
This  electrically  illuminated  tor- 
pedo is  intended  for  use  by  mariners, 
as  an  aid  in  discovering  the  pres- 
ence of  enemy  craft  at  night.  The 
torpedo  may  contain  explosives  if 
desired.  To  prevent  disclosing  the 
location  of  the  ship  dispatching  the 
torpedo,  a  special  electric  time  switch 
is   provided,   which   does   not  close 


the  searchlight  battery  circuit  until 
the  torpedo  has  reached  a  prede- 
termined distance  away  from  the 
ship.  Also  the  inventor  provides  a 
centerboard  or  keel  which  is  auto- 
matically released  after  the  torpedo 
has  reached  the  end  of  its  range, 
and  which  device  helps  to  keep  the 
torpedo  in  a  given  course;  the  in- 
ventor thus  not  relying  on  the  ordi- 
nary rudder  or  plane  steering  me- 
chanism. It  is  possible  to  retrieve 
torpedoes  of  this  type  after  they  have 
performed  their  service. 


Magnetic  Shift  for  Head-Lights 

(No.  1,233,341;  issued  to  Henry  S. 
Gove.) 

Electro-magnetic  shifting  device 
for  rotating  head-lights  of  an  auto 
or  other  vehicle  which  involves  the 
use  of  an  extremely  simple  motor, 
the  head-light  being  mounted  rigidly 
on  a  central  threaded  stem,  which 
engages  a  relatively  heavy  iron  nut. 
Normally    this    nut    is  sufficiently 


heavy  to  fall  to  the  bottom  of  the 
casing,  and  maintain  the  head-light 
in  a  straight  ahead  position.  If 
battery  current  is  past  thru  the 
electro-magnets  at  the  top  of  the 
casing,  the  iron  nut  is  drawn  up- 
ward and  in  so  doing,  it  causes  the 
threaded  cap  just  under  the  magnets 
to  rotate,  thus,  turning  the  central 
stem  on  which  the  head-light  is 
mounted. 


Portable  Lamp  for  Harness 

(No.    1,232,201;   issued  to   Carl  F. 
Brown.) 

A  novel  use  for  a  battery  lamp  de- 
signed so  as  to  be  quickly  attached 
to  or  detached  from  an  ordinary 
harness,  the  wires  carrying  the  cur- 
rent to  the  lamp  being  concealed 
within  the  traces.     Battery  may  be 


placed  in  the  vehicle,  and  when  the 
lamp  is  to  be  used  a  simple  plug 
connector  or  sw'tch  can  be  attached 
to  the  trace  closing  the  lamp  circuit. 
An  auxiliary  switch  mounted  on  the 
vehicle  seat,  may  be  used  if  desired. 
The-  inventor  claims  by  this  arrange- 


ment to  be  able  to  illuminate  the 
road  ahead  of  the  horse,  and  thereby 
prevent  shadows  being  caused  by  the 
animal  from  the  usual  lights  on  the 
vehicle.  When  not  in  use  the  lamp 
attachment  can  be  removed  in  part, 
and  the  remainder  of  the  lamp  pro- 
vides a  neat  ornament  upon  the 
breast  collar.  • 


Fan  Deodorizer 

(No.  1,233,039;  issued  to  Bert  W. 
Flanders.) 
This  invention  provides  a  simple 
deodorizing  attachment  which  may 
be  readily  attached  to  the  wire  cage 
found  on  all  eletcric  fans.  The 
patent  relates  to  refrigeration,  and 


more  especially  to  air  coolers  and  de- 
odorizers which  include  a  fan  or 
other  means  for  pumping  air  into 
contact  with  water  or  other  liquid 
before  it  is  delivered  to  the  point 
of  use.  This  attachment  includes  a 
reservoir  for  water  or  deodorizing 
liquid,  also  a  moistening  surface  with 
a  fabric  sheet  hanging  in  front  of 
the  fan,  and  means  for  delivering 
the  liquid  as  rapidly  as  may  be  de- 
sired to  this  surface,  so  that  the  air 
from  the  fan  is  blown  against  the 
moistened  fabric  and  cooled  or  dried 
by  the  deodorizer  before  it  reaches 
the  point  of  application. 


Thermionic  Amplifying  Circuit 

(No.   1,232,879;   issued  to  Peter  I. 
Wold.) 

This  invention  relates  to  the  ampli- 
fication of  small  continuous  voltages 
or  currents,  and  its  purpose  is  to 
make  it  possible  to  detect  or  measure 
such  voltages  or  currents,  which 
might  not  otherwise  be  detected. 
Audion  type  .  vacuum  amplifiers  are 
utilized   which   are   connected  in  a 


special  circuit  as  shown.  It  will  be 
observed  that  current  from  the  bat- 
tery 16  divides  at  the  middle  point 
•of  the  resistance  15,  and  flows  thru 
the  two  output  circuits.  It  is  also 
apparent  that  the  two  halves  of  re- 
sistance 15  will  be  equal  and  op- 
posite, and  points  C  and  D  will 
normally  be  at  the  same  potential, 
and  no  current  flows  thru  the  gal- 
vanometer 20.  When  key  21  is 
closed,  however,  the  current  will  flow 
thru  the  resistance  6,  and_  if  the 
direction  is  such  as  to  bring  the 
terminal  A  to  a  higher  potential 
than  the  terminal  B,  the  grid  10  will 
have  a  higher  potential  than  grid  11. 
This  results  in  the  current  flowing 
thru  output  circuit  to  amplifier  8, 
being  greater  than  that  of  amplifier 
9.  Thus  point  C  will  be  at  a.  lower 
potential  than  point  D,  and  current 
will  flow  thru  the  galvanometer  20. 


(No. 


Fire-Detecting  Wire 

1,235,028;  issued  to  Charles  A. 
Harsch.) 

This  invention  involves  the  use  of 
a  fusible  conductor  inclosed  within 
the  walls  of  a  cell  or  tube  in  the 
wall  of  which  there  is  provided  an 


tisuto/ar 


.Sfoef  /opt 
Ae/t/rn  conductor 


outlet,  so  that  when  the  metal  be- 
comes plastic,  it  may  be  forced  out- 
ward thru  this  perforation  in  the 
wall  of  this  cell,  and  penetrate  thru 
the  fibrous  insulating  material  sur- 
rounding it,  and  establish  the  de- 
sired electrical  connection  between 
the  inner  and  outer  conductors. 
The  fire-detecting  wire  as  devised  by 
this  inventor  comprises  an  inner 
core  of  easily  fusible  metal,  a  gal- 
vanized steel  tape  of  suitable  breadth 
to  nearly  envelop  a  soft  metal  core, 
leaving  a  longitudinal  slot,  a  braided 
insulated  wrapping  and  an  exterior 
conductor,  formed  preferably  of  a 
galvanized  steel  tape,  helically  dis- 
posed on  the  exterior. 

Radio  Receiving  Circuit 

(No.  1,233,841;  issued  to  Elmer  E. 
Butcher.) 
Radio-telephonic  or  telegraphic  sig- 
nals of  any  characteristic,  and  par- 
ticularly undamped  wave  signals  are 
received  and  made  audible  by  the 
simple  arrangement  here  shown. 
The  patent  covers  the  use  of  a  per- 


Aer/ol 


Rtvolving  condenser. 


■Tel 


iodically  changing  capacity  constant 
in  the  receiving  circuit.  A  con- 
stantly changing  condenser  driven 
by  a  motor  is  shown  in  the  present 
diagram.  It  is  thus  apparent  that 
as  the  revolving  condenser  plates 
rotate,  the  capacity  of  the  condenser 
increases  to  a  maximum,  and  de- 
creases to  a  minimum  periodically; 
thus  throwing  the  secondary  circuit 
into  and  out  of  resonance  with  the 
aerial  circuit,  and  an  audible  signal 
of  a  frequency  proportional  to  the 
speed  of  rotation  of  the  condenser 
is  produced.  No  exact  tuning  is 
necessary  with  this  circuit,  as  the 
revolving  condenser,  within  limits, 
finds  the  exact  point  of  resonance 
automatically. 


Microphonic  Buzzer  Transmitter 

(No.  1,234,650;  issued  to  John  Pat- 
rick Ferriter.) 
A  buzzer  transmitter  for  the  pur- 
pose of  telegraphing  over  a  wire 
telephone  circuit  or  for  use  as  a 
telegraph  transmitter  over  a  radio 
telephone  circuit. 

Microphone  In/rptr 

•    B 


The  apparatus  comprises  an  ac- 
tuating coil  as  shown,  which  is  in- 
closed in  an  open-ended  metal  tube 
(B)  of  brass  or  copper.  At  one  end 
of  the  coil  is  a  spring  interrupter 


(C),  and  at  the  opposite  end  a  mi- 
crophonic transmitter  (D).  The  coil 
may  be  6  inches  long  with  an  iron 
wire  core  %  inch  in  diameter, 
wound  with  five  layers  of  No.  23 
B.  &  S.  magnet  wire.  The  metal 
tube  (B)  absorbs  the  brush  dis- 
charges. The  microphonic  inter- 
rupter (D)  acts  in  unison  with  the 
spring  interrupter  (C),  but  is  not 
electrically  connected  with  it. 
Terminals  (13  and  14)  go  to  the 
line. 

Vacuum  Bulb  Rectifier 

(No.  1,230,004;  issued  to  George  S. 
Meikle.) 

An  improvement  in  vacuum  tube 
rectifiers  involving  the  use  of  an  in- 
candescent cathode  device  in  the 
manner  shown.     This  idea  provides 


a  rugged  main  cathode,  and  separate 
or  auxiliary  electrode  which  oper- 
ates in  conjunction  with  such  cath- 
ode to  spring  a  starting  arc  which 
heats  the  cathode  to  incandescence, 
preliminary  to  starting  the  main 
arc.  The  cathode  tip  perferably 
consists  of  tungsten;  the  space  with- 
in the  bulb  should  be  carefully 
evacuated  of  all  gases  and  vapors, 
and  the  envelop  is  then  filled  with 
an  inert,  gas,  such  as  hydrogen, 
argon,  etc.  When  the  tube  is  to 
be  started,  a  suitable  heating  cur- 
rent is  conveyed  to  the  starting 
electrode  9,  from  a  special  winding 
on  the  transformer  as  shown. 


Wind- Wheel  Electric  Generator 

(No.  1,233,232;  issued  to  Albert  H. 
Heyroth.) 
A  very  clever  form  of  wind-wheel 
electric     generator    in     which  the 


COPIES  OF  ANY  OF  THE  ABOVE  PATENTS  SUPPLIED  AT  10c  EACH 


wind-wheel  itself  acts  as  the  rotor 
of  an  alternating  current  dynamo. 
The  rotating  element  simply  carries 
inductor  plates,  which  are  caused 
to  move  by  a  series  of  stator  poles, 
which  poles  carry  a  series  of  elec- 
tro-magnetic windings.  The  device 
acts  in  the  same  way  as  an  alter- 
nating current  generator,  and  also 
serves  as  its  own  exciter.  The 
terminals  of  the  stator  windings 
may  be  connected  with  a  rectifier 
to  change  the  alternating  current 
into  a  continuous  one  when  so  de- 
sired. 


October,  1917 


THE  ELECTRICAL  EXPERIMENTER 


409 


Under  this  heading  are  publisht  electrical  or  mechanical  ideas  which 
our  clever  inventors,  for  reasons  best  known  to  themselves,  have  as  yet 
not  patented.  We  furthermore  call  attention  to  our  celebrated  Phoney 
Patent  Offizz  for  the  relief  of  all  suffering  daffy  inventors  in  this  country 
as  well  as  for  the  entire  universe. 

We  are  revolutionizing  the  Patent  business  and  OFFER  YOU  THREE 
DOLLARS  ($3.00)  FOR  THE  BEST  PATENT.  If  you  take  your  Phoney 
Patent  to  Washington,  they  charge  you  $20.00  for  the  initial  fee  and  then 


Phoney  Patents 


you  haven't  a  smell  of  the  Patent  yet.  After  they  have  allowed  the  Pat- 
ent, you  must  pay  another  $20.00  as  a  final  fee.  That's  $40,001  WE 
PAY  YOU  $3.00  and  grant  you  a  Phoney  Patent  in  the  bargain,  so  you 
save  $43.00!!  When  sending  in  your  Phoney  Patent  application, 
be  sure  that  it  is  as  daffy  as  a  lovesick  bat.  The  dafner,  the  better. 
Simple  sketches  and  a  short  description  will  help  our  staff  of  Phoney 
Patent   examiners    to    issue   a   Phoney    Patent    on   your   invention    in  a 

jiffy.  


PHONEY  PATENT  OFFIZZ 


FIRST  PRIZE,  $3.00:  Smokelight.    Works  on  Vacuum  Cleaner  Principle.     Suction  Created  by  Smoking,  Operates  Air  Turbine,  Which 
in  Turn  Energizes  Dynamo.    The  Latter  Charges  Storage  Battery   Which   Feeds  the  Current  to  Electric  Lamp.     Thus  Collisions  in 
Dark  Are  Avoided  and  Keyholes  Are  Found  Easily.     Inventor:  F.   R.  Prey,  Somerville,  Mass. 


ELECTRIC  SAI LO  MO  BO  AT:    Wind  Fills  Sails  Which  Slowly  Move  Ship.    Water  Turns  Paddles  1,  Which  Thru  Gear  2  Work  Dynamo  3, 
the  Latter  Charging  Storage  Battery  4.     This  in  Turn  Drives  High-Speed  Motor  5,  Which  Turns  Propeller  6  at  3898  R.P.M.     Thus  Ship 
Is  Driven  Forward   at  49'/4  Nots  an  Hour,     Inventor:    Albert  Branson,  Logan,  Pa. 


410 


THE  ELECTRICAL  EXPERIMENTER 


October,  1917 


QUESTION  BOX 


This  department  is  for  the  sole  benefit  of  all  electrical  experimenters.  Questions  will  be  answered  here  for  the  benefit  of  all,  but  only 
matter  of  sufficient  interest  will  be  publisht.    Rules  under  which  questions  will  be  answered: 

1.  Only  three  questions  can  be  submitted  to  be  answered. 

2.  Only  one  side  of  sheet  to  be  written  on;  matter  must  be  typewritten  or  else  written  in  ink,  no  penciled  matter  considered. 

3.  Sketches,  diagrams,  etc.,  must  be  on  separate  sheets.  Questions  addrest  to  this  department  cannot  be  answered  by  mail  frep  of  charge. 

4.  If  a  quick  answer  is  desired  by  mail,  a  nominal  charge  of  25  cents  is  made  for  each  question.  If  the  questions  entail  considerable  re- 
search work  or  intricate  calculations  a  special  rate  will  be  charged.   Correspondents  will  be  informed  as  to  the  fee  before  such  questions  are 

answered. 


RESISTANCE  OF  SEA- WATER. 

(842-A.)  O.  Saterdale,  E.  Boston,  Mass., 
inquires  : 

Q.  1.  What  is  the  resistance  of  sea- 
water  and  what  current  could  be  transmit- 
ted thru  1,000  feet  of  it? 

A.  1.  The  resistance  of  sea  water  varies 
somewhat  of  course,  but  it  has  an  approxi- 
mate resistance  of  5  ohms  per  cubic  centi- 
meter. 

Your  question  is  very  indefinite,  as  it 
makes  all  the  difference  in  the  world 
whether  you  wish  to  compute  the  amount 
of  current  which  could  be  transmitted  thru 
one  thousand  feet  of  sea  water  in  a  pipe; 
which  would  of  course  be  a  comparatively 
easy  computation;  or  whether  you  wish  to 
make  such  a  calculation  for  an  open  body 
of  sea  water,  such  as  in  a  harbor  or  inlet. 
In  this  case,  the  matter  would  become  very 
involved  indeed,  and  a  number  of  sound- 
ings and  breadth  measurements  of  the  body 
of  water  .would  have  to  be  taken,  and  a 
mean  of  these  values  selected,  so  as  to 
obtain  the  average  cross-sectional  area  of 
the  water.  The  resistance  of  a  cross-sec- 
tion of  sea  water  10  centimeters  square 
would  only  be  1/100  of  the  resistance  of  a 
cubic  centimeter,  etc.  The  current  in 
amperes  which  could  be  transmitted  thru 
a  certain  resistance  of  sea  water  would  be 
given  by  Ohm's  law  or 
E 

C  =  —. 
R 


applied  to  radio  keys  and  other  switches 
carrying  heavy  currents  and  liable  there- 
fore to  severe  arcing,  lies  in  the  fact  that 


CONDENSER  FOR  REDUCING 
SPARKING. 

(842.)  Charles  Honeywell,  Gloversville, 
N.  Y.,  asks : 

Q.  1.  Can  you  suggest  proper  size  of 
condenser  to  eliminate  sparking  at  bell  cir- 
cuit contact  shown  in  diagram? 

A.  1.  Concerning  the  special  electrical 
contact  which  you  are  experimenting  with, 
would  advise  that  without  more  exact  de- 
tails as  to  how  you  have  the  special  contact 
arranged,  we  cannot  very  well  advise  you 
as  to  how  to  overcome  the  trouble. 

We  should  think  that  it  would  be  pos- 
sible to  make  the  spring  tension  acting  on 
your  contact  sufficiently  strong  so  that  the 
contact  will  not  be  jarred  shut  by  a  slight 
mechanical  disturbance. 

A  condenser  will  only  help  you  indirectly 
in  solving  this  problem,  if  you  have  the 
contact  member  arranged  so  delicately  that 
the  slightest  jar  will  cause  it  to  close.  We 
would  like  to  advise  you  further,  but  feel 
that .  it  would  only  be  a  waste  of  time  to 
discuss  matters  which  we  do  not  quite 
understand  for  the  reasons  above  stated. 
Your  trouble  apparently  seems  to  lie  in  the 
manner  of  arrangement  of  the  contact. 
Besides  the  condenser  the  principle  of  the 
magnetic  blow-out  could  be  applied  to  over- 
come the  arcing  at  your  contact,  but  even 
the  latter  would  seem  to  hardly  be  of  any 
distinct  benefit  to  you,  if  the  design  of 
the  contact  is  not  properly  carried  out. 

The  principle  of  the  magnetic  blast  as 


O  8efl 

w 

\  Ba/f. 

_ — ? 

0-S4Z 

e 

A  Simple  Yet  Difficult  Problem.  It  Is  Re- 
quired to  Break  This  Circuit  With  a  Mini- 
mum of  Sparking  and  the  Interrupter  Is  a 
Delicately  Mounted  One,  Easily  Vibrating 
With  a  Slight  Jar. 


m 


ODD  PHOTOS  WANTED 
AT  $1.00  EACH!!! 

Now  is  the  time   to  make  your 
\  Kodak  pay  for  itself  in  a  real  practi- 
\  cal  way.     We  are  after  interesting 
\  photographs    of  out-of-the-ordinary 
|  electrical,  radio   and  scientific  sub- 
|  jects  and  are  willing  to  pay  $1.00  cash 
\  for  every  one  we  can  use.  Please 
|  bear  in  mind  that  for,  half-tone  re- 
■  production  in  a  magazine,  a  photo- 
graph should   be  particularly  sharp 
|  and  clear.    Of  course,  if  a  subject 
happens   to   interest  us  particularly 
well,  we  can  have  the  photo  retouched. 
\  For  the  general  run  of  subjects,  how- 
ever, it  does  not  pay  to  go  to  such 
expense.   Therefore,  please  take  pains 
to  properly  focus  and  expose  your 
pictures.     It   often   happens   that  a 
really  mediocre  subject  well  photo- 
graphed wins  approval  over  an  ex- 
cellent subject  poorly  photographed. 
And  don't  send  us  plate  or  film  "nega- 
tives"; send  unmounted  or  mounted 
"prints,"  preferably  a  light  and  a  dark 
one. 

As  to  what  to  photograph:  Well, 
that's  hard  for  us  to  say.  We  leave  \ 
that  up  to  you,  and  every  reader  now  \ 
has  the  opportunity  to  become  a  re-  \ 
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a  strong  electro-magnet  is  connected  in 
series  with  the  circuit,  in  most  cases.  This 
magnet  for  small  circuit  breakers,  may  be 
of  about  the  same  size  as  a  telegraph 
sounder  electro-magnet,  and  in  any  case, 
this  series  blow-out  magnet  should  be 
wound  with  wire  of  the  same  size  as  that 
used  on  the  primary  of  the  transformer, 
spark  coil  or  other  apparatus  which  the 
key  controls. 

It  is  usual  to  allow  from  800  to  1,000 
circular  mils  per  ampere,  in  designing  such 
blow-out  coils,  and  the  electro-magnet 
should  be  provided  with  suitable  tapered 
pole-pieces  with  a  small  air  gap  between 
them,  and  so  arranged  that  the  break  be- 
tween the  platinum  or  other  contacts  of 
the  circuit-breaker  takes  place  between  the 
magnet  pole-pieces.  In  this  way  the  arc 
will  be  blown  out  by  the  magnetic  field. 


ELECTROLYTIC  PRODUCTION  OF 
HYDROGEN. 

(844.)  A.  Luchs,  Jr.,  Ridgeway,  Pa., 
asks  a  number  of  questions  regarding  the 
electrolytic  production  of  hydrogen. 

A.  1.  With  respect  to  the  explosive  qual- 
ity of  hydrogen  gas,  would  say  that  this 
is  an  explosive  only  when  mixed  with 
oxygen  or  with  air,  which  is  the  same 
thing. 

The  most  efficient  way,  and  the  one  now 
used  commercially  in  the  largest  oxygen- 
hydrogen  producing  plants  in  the  country, 
is  that  producing  hydrogen  or  oxygen  gas 
by  the  electrolysis  of  water,  which  is  ac- 
complisht  by  passing  a  strong  electric  cur- 
rent thru  it. 

The  following  data  is  given  by  one  of 
the  leading  manufacturers  of  oxygen  and 
hydrogen  gas.  A  current  of  2  volts  and 
600  amperes  is  used  per  cell  and  4.8  cubic 
feet  of  oxygen  and  9.6  cubic  feet  of  hydro- 
gen per  hour  are  produced  with  this  cur- 
rent of  1,200  watts.  The  U.  S.  Army  bal- 
loon electrolizers  use  1,000  watt  hours  to 
produce  7T/2  cubic  feet  hydrogen  and  5.76 
gallons  of  water  per  1,000  cubic  feet  of 
hydrogen  are  required.  The  electrolytic 
apparatus  used  for  producing  these  two 
important  commercial  gases  is  usually  de- 
signed so  that  the  two  gases  are  collected 
separately  and  independently;  the  hydrogen 
gas  being  evolved  at  the  negative  electrode 
and  the  oxygen  gas  at  the  positive  elec- 
trode. You  will  do  very  well  to  obtain  a 
copy  of  U.  S.  Patent  No.  1,219,966  describ- 
ing an  improved  form  of  electrolytic  gas 
generator  as  used  for  the  commercial  pro- 
duction of  these  products,  and  which  we 
can  supply  at  10  cents. 

With  reference  to  the  proper  ratio  of 
hydrogen  gas  and  air,  to  make  the  most 
explosive  mixture,  we  would  suggest  that 
you  try  this  out  by  experiment,  as  it  would 
depend  to  some  extent  on  the  quality  of 
the  air ;  i.e.,  it  would  vary  for  different 
levels,  and  an  adjustable  mixer  valve  should 
be  used  in  any  such  work  as  this,  similar 
to  the  carburetor  employed  universally  on 
all  gasoline  automobiles. 


October,  1917 


THE  ELECTRICAL  EXPERIMENTER 


411 


LARGE  AND  SMALL  WIRE  IN 
SAME  CIRCUIT. 

(845)    E.  E.  C  1  Ohio,  asks  whether 

several  sizes  of  wire  can  be  used  in  the 
same  circuit  in  a  satisfactory  manner. 

A.  1.  With  regard  to  running  a  3-phase 
7200-volt  line  one-half  mile,  to  deliver  cur- 
rent to  a  bank  of  3-25  K.V.A.  25-cycle, 
6600-volt  to  440-volt  transformers  for 
power  load  would  advise  as  follows : 

We  have  not  made  any  calculations  on 
this  problem,  but  assume  that  you  are  tak- 
ing care  of  these  calculations  yourself. 
However,  regarding  the  use  of  various  sizes 
of  wire  in  the  transmission  line,  would 
advise  that  so  long  as  the  smallest  size  of 
conductor  used  is  not  below  the  minimum 
allowable  cross  sectional  area,  in  circular 
mils,  as  computed  by  the  usual  A.C.  for- 
mula for  such  circuits,  then  it  will  not 
matter  in  the  least  for  all  practical  pur- 
poses, whether  you  use  several  different 
sizes  of  wire  in  the  circuit  or  not. 

That  is  if,  say,  No.  6  B  &  S  conductor 
was  given  by  the  usual  voltage-drop  for- 
mula, then  so  long  as  any  of  the  pieces  of 
wire  to  be  used  are  not  smaller  than  No. 
6  gage,  the  circuit  will  operate  satisfacto- 
rily. Of  course  it  is  the  usual  case  that  no 
one  would  want  to  use  sections  of  conduc- 
tor larger  in  size  than  that  absolutely  re- 
quired by  the  conditions  surrounding  the 
problem,  but  of  course  in  your  case,  there 
is  an  exception  as  you  state,  owing  to  the 
fact  that  you  have  a  quantity  of  various 
sized  conductors  on  hand  for  the  installa- 
tion in  question. 


REPELLING    TORPEDOES  WITH 
A.  C.  ELECTRO-MAGNETS. 

(846.)  John  Davidson,  Ohio,  asks  several 
questions  regarding  A.  C.  magnets  to  be 
used  for  repelling  torpedoes. 

A.  1,  We  have  considered  such  an  elec- 
trical device  as  you  describe,  and  which  is 
supposed  to  repel  metallic  bodies  such  as 
those  made  of  steel  or  iron. 

Considered  from  a  fundamental  electri- 
cal viewpoint,  an  ordinary  magnet  excited 
by  a  direct  current  will  not  exert  any  re- 
pelling effect  on  an  iron  or  other  body.  It 
is  possible  to  create  a  magnetic  repulsion 
effect  if  powerful  alternating  current  elec- 
tro-magnets are  used,  but  this  effect  exists 
only  over  a  distance  of  a  few  inches  at  the 
most,  and  several  inventors  have  recently 
proposed  that  it  would  be  a  good  idea  to 
put  a  belt  of  these  powerful  A.C.  electro- 
magnets around  the  waterline  of  a  steam- 
ship so  as  to  repel  torpedoes  and  the  like. 

While  we  are  on  the  subject,  it  is  well  to 
point  out  that  if  this  arrangement  was  car- 
ried out  that  firstly,  the  cost  would  be  prac- 
tically prohibitive,  and  secondly  there  would 
be  no  repulsion  effect  exerted  on  the  tor- 
pedo, which  is  made  of  steel,  for  the  reason 
that  it  would  not  be  of  the  proper  shape. 
To  produce  a  repulsion  effect  between  an 
iron  core  within  an  a.c.  magnet  coil  and  a 
copper  or  aluminum  inductor,  the  latter 
must  be  made  in  a  ring  form  either  square 
or  round,  so  that  induced  currents  are  set 
up  in  this  ring  which  will  produce  within 
the  ring  an  opposing  magnetic  field,  which 
reacts  with  the  inducing  a.c.  field  of  the 
electro-magnet  just  mentioned. 


COMPUTING  SIZE   OF  ELECTRIC 
LIGHT  WIRING. 

(847.)  Roy  N.  Meier,  Wayne,  Nebr., 
wishes  to  know  how  the  size  of  wire  for 
lighting  circuits  is  computed. 

A.  1.  One  of  the  simplest  and  most  reli- 
able rules  for  computing  the  proper  size  of 
a  conductor  to  be  used  for  wiring  a  house 
for  lights,  etc.,  is  the  modification  of  Ohm's 
law  which  states  that  the  resistance  of  the 
wire  in  the  circuit  (both  legs)  in  ohms  should 
equal  the  volts  drop  in  the  circuit,  divided 
by  the  current  in  amperes  in  the  circuit. 


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THE  ELECTRICAL  EXPERIMENTER 


October,  1917 


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It  is  usual  to  allow  about  3  volts  drop 
from  the  main  panel  board  to  the  lamps. 

In  making  the  final  selection  of  the 
proper  size  of  wire  to  be  used  for  light  and 
power  circuits  reference  should  be  made  to 
the  Fire  Underwriters'  rules  and  tables, 
and  if  they  specify  a  slightly  larger  con- 
ductor than  the  one  given  by  the  above  for- 
mula, then  that  is  the  one  that  should  be 
used  of  course. 

With  reference  to  the  size  of  fuses  to 
be  used  on  the  main  panel  board,  these 
should  be  a  multiple  of  the  fuses  in  the 
branch  circuits.  For  example  if  a  panel 
board  supplies  four  branch  blocks,  each 
fused  at  5  amperes,  then  the  panel  board 
should  be  fused  at  4  times  5,  or  20  amperes, 
etc. 


WIRING  DIAGRAM. 

(848.)  Leroy  F.  Bremmer,  Fort  Dodge, 
Iowa,  wants  to  know : 

Q.  1.  What  is  the  wave  length  of  an 
aerial  80  feet  long,  4  wires,  55  and  38  feet 
high,  with  lead-in  100  feet  long. 

A.  1.  The  wave  length  of  your  antenna 
is  350  meters. 

Q.  2.  Please  show  diagram  of  connec- 
tions of  a  one-step  amplifier  which  can  be 
changed  from  a  10,000  meter  undamped 
wave  set  to  a  4,000  meter  spark  set  by 
switches.  Please  show  all  necessary  in- 
struments in  hookup. 

A.  2.  Diagram  herewith  shows  connec- 
tions of  the  necessary  instruments.  The 
double-throw,  double-pole  switch  is  em- 
ployed for  changing  from  the  10,000  meter 
coupler  to  the  4,000  meter  coupler.  In  re- 
ceiving spark  stations  it  is  essential  that  the 
grid  loading  coil  is  short-circuited  by 
means  of  the  switch  as  shown.  To  receive 
spark  station  the  D.  P.  D.  T.  switch  is 
thrown  to  the  left  and  for  undamped  wave 
it  is  placed  to  the  right. 


IS  HYDROGEN  SULFID  IN  WATER 
A  PHYSICAL  OR  A  CHEMICAL 
SOLUTION? 

(849.)  S.  Lenkin,  Washington,  D.  C, 
wants  to  know  if  hydrogen  sulfid  (H2S)  in' 
water  is  a  physical  or  a  chemical  solution, 
and  why. 

A.  1.  Hydrogen  sulfid  in  water  is  a  phys- 
ical solution.  When  the  gas  is  past  into 
the  water  there  is  no  evidence  of  any  effer- 
vescence or  of  any  precipitat  forming  (un- 
less lead  is  present  in  the  water  which  will 
cause  the  H2S  to  precipitat  the  lead  as  an 
insoluble  sulfid).  This  operation  is  some- 
times called  a  simple  solution,  the  origi- 


substance  (H2S)  is  present  in  the  liquid, 
and  can  be  obtained  by  evaporation.  (This 
is  not,  however,  the  case  with  HC1.)  The 
solution  of  the  gas  will,  however,  give  cer- 
tain chemical  reactions,  as,  turning  litmus, 
and  when  deposited  on  a  silver  coin,  will 
produce  a  black  stain  of  silver  sulfid. 


OSCILLATING  A.  C.  MOTOR. 

(850.)  E.  W.  Cleave,  Oakland,  Calif., 
wants  to  know  if  an  A.C.  motor  can  be 
built  in  which  the  rotor  will  oscillate  back 
and  forth  instead  of  rotating. 

A.  1.  Concerning  oscillating  squirrel- 
cage  A.C.  motor,  we  must  say  to  the  best 
of  our  knowledge,  there  is  no  method  of 
winding  such  a  motor  so  as  to  cause  the 
rotor  to  oscillate  back  and  forth  thru  say, 


nal  ^th  of  a  revolution  as  you  suggest. 

We  would  suggest  that  you  take  up  this 
matter  with  the  Engineering  Department 
of  the  General  Electric  Co.,  Schenectady, 
N.  Y.,  as  we  have  an  idea,  if  we  recollect 
correctly,  that  that  concern  have  a  special 
alternating  current  apparatus,  which  oper- 
ates on  a  principle  somewhat  like  the  one 
you  outline. 


LARGE  SPARK  COIL  DESIGN. 

(851.)  B.  P.  B.,  Chicago,  111.,  asks  about 
constructing  a  large  spark  coil. 

A.  1.  It  is  often  the  case,  as  you  suggest 
that  the  efficiency,  and  therefore  the  length, 
of  spark  produced  by  a  given  induction  coil 
will  be  intensified  by  substituting  a  vulcan- 
ized fiber,  or  a  hard  rubber  tube  for  a  paste- 
board one,  if  that  is  the  kind  of  tube  now 
separating  the  primary  and  secondary  coils 
in  your  apparatus. 

Some  makers  have  used  to  very  good 
advantage  a  glass  tube,  the  point  at  issue 
being  to  have  the  very  best  insulation  possi- 
ble between  the  primary  and  secondary, 
owing  to  the  very  high  voltages  induced  in 
the  secondary  winding,  which  will  of  course 
always  attempt  to  jump  the  shortest  possi- 
ble path  or  gap,  such  as  around  the  ends 
of  the  primary  insulating  tube  into  the  iron 
core. 

For  this  reason  in  designing  large  induc- 
tion coils,  above  the  2-inch  spark  size,  it  is 
invariably  the  practise  to  so  proportion  the 
secondary  winding  that  it  shall  not  come  all 
the  way  to  the  end  of  the  primary  insulat- 
ing tube,  but  a  considerable  distance  from 
it. 

You  are  correct  in  your  statement  accom- 
panied by  diagram  (Fig.  1)  relative  to  the 
connection  between  various  secondary  sec- 
tions, but  this  is  the  older  and  practically 


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ters Wave  Length. 


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Look  inside  your  storage  battery  through  the 
patented  open  window.  See  condition  of 
plates  and  height  of  electrolyte.  If  vouneeda 
new  automobile  starting  Battery  buy  a  Jewel 
and  save  money.     6-tiO  Special  S8.50. 

Motorcycle  Electric  Lighting  System 
The  Jewel  Generator  Motorcycle  Storage  Battery  and 
complete  lighting  system  is  in  great  demand.  Agents 

"anted.     Write  for  prices  and  catalog  E. 

JEWEL  ELECTRIC  COMPANY,  112  N.  Fifth  Av.,  CHICAGO 


You  benefit  by 


mentioning  "The  Electrical  Experimenter"  when  writing  to  advertisers. 


October,  1917 


THE   ELECTRICAL  EXPERIMENTER 


413 


obsolete  manner  of  making  these  connec- 
tions, and  most  always  leads  to  dissatis- 
faction at  an  early  date,  for  the  reason  that 
there  is  a  very  high  potential  always  exist- 


term.l 


Outside  lead 
L 


term  2 


termL 


Insiae  leaa 


term.' 


i 


& 


Old  and  New  Method  of  Arranging  Spark 
Coil  S^nnrtarv  cQrtions.  In  Method  of  Fig. 
1,  the  Full  Potential  of  Each  "Pie"  Tends  to 
Jump  Between  the  Lead  and  the  Winding. 

ing  between  the  top  of  one  section  or  "pie," 
and  the  down-coming  lead  wire  from  the 
adjacent  "pie."  It  is  the  best  and  modern 
practise  to  connect  first  two  inside  leads 
together  and  then  two  outside  leads,  etc., 
etc.,  reversing  every  other  "pie"  of  course 
as  it  is  placed  in  position  over  the  primary 
insulating  tube.  The  Editor  has  generally 
found  it  most  convenient  and  practical  to 
secure  the  primary  element  with  its  insulat- 
ing tube  in  place  in  a  vertical  position  by 
means  of  wooden  blocks,  etc.  This  could 
easily  be  arranged,  and  a  few  blocks  may 
be  used  if  necessary  to  form  a  sufficiently 
high  base  at  the  point  where  the  first  "pie" 
will  come.  All  leads  should  be  soldered, 
using  a  non-corrosive  flux.  You  will  find 
a  number  of  excellent  books  on  this  sub- 
ject illustrated  in  our  "Book  Catalog." 

BUZZER  TRANSMITTER  FOR 
LIGHTING  CIRCUITS. 

(852.)  Cecil  Mathers,  Miami,  Fla.,  de- 
sires a  hook-up  for  a  buzzer  system  to 
work  on  lighting  circuits. 

A.  1.  We  give  you  herewith  diagram  of 
connections  for  two  buzzers,  batteries  and 
keys  to  be  used  with  ground  return  and 
electric  light  or  other  circuit,  for  the  pur- 
pose of  transmitting  telegraphic  signals 
over  a  one  mile  range. 

Both  telephone  receivers  (of  the  usual 
75-ohm  type)  should  be  connected  to  the 
same  line  wire;  i.e.,  both  of  them  should 
be  connected  to  either  the  positive  or  the 
negative  line  wire.  If  you  experience  any 
-trouble  ^"p  to  i  ^rounded  system,  a  small 
fixt  condenser  should  be  connected  in  series 
with  the  telephone  receiver  at  each  station. 


Lighting  Circuit 


\°%r75  otim  tet  receiver C3 


© 


Simple  Buzzer  Telegraph  for  Use  on  Light- 
ing or  Power  Circuits. 


JAPANESE  USE  ELECTRICITY. 

The  use  of  electricity  for  lighting  is  rap- 
idly increasing  in  Japan,  even  in  the  homes 
of  the  poorest  classes  in  the  cities. 


LEARN  WIRELEi 


SERVE  YOUR  COUNTRY 


in  an  important  trained  capacity.    Several  thou- 
sand operators  are  needed  for  Army  and 
Navy  Service,  our  new  merchant 
marine  and  air  fleet. 


The  licensed  Em- 
ployment Department 
finds  temporary  day  employment 
for  those  who  must  earn  while  learning. 

ASK  FOR  FOLDER  "B" 

EASTERN  DISTRICT  Y.  M.  C.  A. 

Marcy  Ave.,  near  Broadway,  Brooklyn,  N.  Y. 

13  minutes  to  New  York  City  Hall 


.A  USEFUL  MODERATE  PRICE  INK  PENCIL 


y,    y,  "  a.  ■*  n*h  i/o         •/       Tne  only  perfect  non-leakable,  will  suit  any  hand. 

Vl**k>Cl<ris  *  M.UU  Ink  renCIIS  Guaranteed.  Last  a  lifetime.  Great  for  general 
writing  or  manifolding.  Pure  l'ara  rubber  with  precious  metal  point.  Can  be  carried  point  down. 
Made  in  red  and  black.  Long  and 
short.  (Special!  8  Ins.,  black,  $1.25.)' 
Mall  orders  promptly  filled.  FKEE  supply,, 
of  ink  with  retail  orders.    Agents  wanted. 

J.  R,  ULLRICH  &  CO., 
27  Thames  Street  New  York 


"  THERE'S  MONEY  IN  IT'* 

^ILEARN  TELEGRAPHYfE^ 

„~MORSE  /^D  WIF^ELESSizr-^ jpz* 
TEACH  YOURSELF 


in  half  the  usual  time,  at  trifling  cost,  with  the 
wonderful  Automatic  Transmitter,  THE  OMNIGRAPH. 

Sends  unlimited  Morse  or  Continental  messages,  at 
any  speed,  just  as  an  expert  operator  would. 

Adapted  by  U.  S.  Gov't.    4  stylet.    Catalogue  free. 

OMNIGRAPH  MFC.  CO. 

39L  Cortlandt  St.  New  York 


an  Behind  the  Key 


is  equally  as  important  today  as  the  Man  behind  the 
gun,  as  well  as  the  Man  in  the  trench. 
The  Government  and  Merchant  Marine  need  thousands  of 
TRAINED  operators  now,  the  demand  far  exceeding  the  sup- 
ply.   Men  are  needed  urgently  for  the  Naval  Reserve,  Naval 
Militia,  and  Signal  Corps,  etc.,  etc. 

Pick  your  rating  before  you  are  drafted. 

Special  short  code  courses,  Day  or  Evening  for  those  desiring 
to  join  any  branch  of  Radio  for  Government  Service.  Fall  classes 
both  Day  and  Evening  start  Oct.  1st.  Send  in  your  enrollment 
today.    Students  from  all  over  the  country. 


*  Eastern  Radio  Institute, 
|        899B  Boylston  St.,  Boston. 

I  Please  send  to  address  below  your  64-page  book- 
|  let,  giving  full  information  about  your  school. 

|  Name   


Address 


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414 


THE  ELECTRICAL  EXPERIMENTER 


October,  1917 


You  May  Uarn  Theory,  Code  and  Laws  of  Radio 
Comm  unication  in  Our  School  or  at  Your  Home 

fitting  you  for  positions  paying  good  salaries  with  wonderful 
chance  to  travel  the  world  over.    It's  the  most  interesting  pro- 
fession known  and  the  demand  for  skilled  operators  is  increasing. 
Send  stamp  for  catalog  giving  facts.      Resident  classes 
open  0c':.  2nd. 

NATIONAL  RADIO  SCHOOL,  14th &  U  Sts.,  N.  W.,  Washington,  D.C. 

WASHINGTON  ^^^^ 


The  Monitor  Detector  System 

FOR  THE 

Automatic  announcement  of  fire  in  its  incipiency. 
Automatic  control  and  closing  of  factory  fire  doors  and  shutters. 
Annunciation  of  rising  temperatures  in  refrigeration  plants. 
Annunciation  of  falling  temperatures  and  automatic  lighting  of  heaters  in 
citrus  groves. 

Automatic  control  and  dropping  of  asbestos  fire  curtain  and  opening  all 
theatre  exit  doors. 

Control  of  automatic  sprinklers,  etc. 

Complete  protection  for  hotels,  homes,  steamships,  theatres,  factories, 
warehouses,  piers,  etc. 

Illustrated  booklet  mailed  upon  application. 
Agents  wanted  and  territorial  rights  granted. 
Let  us  give  you  a  demonstration. 

NEW  YORK  BRASS  FOUNDRY  CO.,  104  Centre  St.,  N.  Y.,  U.  S.  A. 

Finished  Brass  Specialties         Marine  Supplies  Fire         Equipment  for  Steamships  and  Buildings 


P»t  K«by. 
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other  patents 
pending 


UNIVERSAL  ELECTRIC  MOTORS 


OPERATING  ON  A.  C.  OR  D.  C. 

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A  MOTOR  OF  UNIVERSAL  APPLICATION 

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Makers  of  RACINE  FANS,  VACUUM  CLEANERS,  VIBRATORS  AND  MOTOR  APPLIANCES  of  all  kinds 


MAGNETIC 
RECTIFIER 

Patented 
April  1910 


F-F  BATTERY  BOOSTER 

NEW— FULL    WAVE— HIGH  EFFICIENCY 

For  Public  or  Private  Use 

You  yourself  can  KEEP  YOUR  BATTERY 
FULLY  CHARGED  and  give  it  a  REFORMING 
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save  a  big  charging  bill  and  expensive  rental  bat- 
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Big  profit  in  taking  batteries  in  to  recharge. 

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THE  FRANCE  MANUFACTURING  CO.,  Cleveland,  Ohio 

Jobbers    and    Dealers    Throughout    the  United 
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STORAGE  BATTERIES  FOR  ALL  PURPOSES 

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WE  MANUFACTURE  BATTERIES 
FOR  EACH  MAKE  OF  AUTOMOBILE 


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N.  Y. Depot— 974  8th  Are.,  N.  Y.  City 


ELECTRIC  "ZIG-ZAGGER"  AIDS 
SHIPS  TO  FOIL  U-BOATS. 

{Continued  from  page  367) 

the  first  officer  of  one  of  the  large  British 
merchant  ships  has  invented  a  simple  and 
very  effective  "zig-zag  control  board,"  which 
•is  herewith  illustrated.  It  consists  of  a 
board  about  two  or  three  feet  square,  carry- 
ing in  its  center  a  clock,  and  on  each  side 
of  the  clock  a  series  of  alternate  green  and 
red  cards  and  glow  lamps,  each  card  and 
lamp  corresponding  to  the  starboard  and 
port  courses  on  which  the  ship  is  being  navi- 
gated at  any  given  time.  Above  the  clock, 
extending  across  the  head  of  the  "board,  is 
plotted  a  zig-zag  course  which  it  will  take 
the  ship  one  hour  to  cover. 

In  the  accompanying  chart  (top)  the 
straight  line  represents  the  true  course 
which,  in  this  case,  is,  let  us  say,  due  north. 
The  ship  commences  her  zig-zag  course 
at,  say,  2  o'clock,  at  which  hour  the  helm 
is  thrown  over  and  the  ship's  course  is 
altered  30  degrees  to  port  of  the  true  course. 
[The  original  conception  of  this  "zig-zag" 
control  board  was  limited  to  automatically 
warning  the  helmsman  every  time  the  rud- 
der was  to  be  thrown  over.  The  helms- 
man then  set  the  electrical  clock  contact  to 
ring  after  the  next  leg  of  the  course  had 
been  completed,  thus  introducing  manual 
control,  which  may  or  may  not  be  a  de- 
sirable feature.  The  editors  have  given  this 
device  considerable  thought  and  suggest  a 
full  automatic  electrical  control  of  the  rud- 
der during  such  "zig-zag"  runs,  leaving  of 
course  the  manual  control  always  operative 
in  the  event  that  the  course  might  have  to 
be  suddenly  changed  or  when  the  automatic 
control  might  fail.]  She  continues  on  this 
course  until  seven  and  one-half  minutes 
past  2  o'clock,  when  the  Minute-hand  of 
the  clock  makes  electrical  contact  with  a 
bell  which  rings  loudly,  announcing  that  the 
time  has  come  to  change  course  again. 
(In  the  original  scheme;  in  the  revised 
plan  shown  in  the  diagram  herewith  the 
contact  closed  by  the  clock  hand  causes  the 
proper  relay  to  function,  running  the  "port" 
or  "starboard"  rudder  motor  for  a  prede- 
termined time,  sufficient  to  pull  the  rudder 
over  sufficiently  to  start  the  new  course.) 
The  helm  is  now  thrown  over,  and  the  ship 
is  put  on  a  course  45  degrees  to  starboard 
of  the  true  course.  This  course  is  main- 
tained for  ten  minutes,  when  another  elec- 
trical contact  is  made,  the  bell  rings,  and 
the  ship  is  turned  the  necessary  number  of 
degrees  to  port  until  she  is  on  a  northern 
course,  parallel  with  her  true  course. 

There  are  seven  changes  of  course  dur- 
ing the  hour,  at  the  end  of  which,  the  ship 
is  back  again  on  her  true  course.  In  this 
particular  zig-zag  a  12-knot  ship  loses  two 
knots  of  distance  in  one  hour,  which  rep- 
resents a  loss  of  about  fifty  miles  in  the 
twenty- four  hours ;  but  it  is  better,  surely, 
to  lose  fifty  miles  of  distance  than  to  lose 
the  ship. 

The  course  herewith  shown  is  a  purely 
suppositious  one.  The  navigator  can  plot 
any  course  he  may  desire  in  a  few  minutes' 
time,  and  having  done  that,  he  has  merely 
to  shift  the  electrical  contacts  from  hole  to 
hole  around  the  periphery  of  the  clock,  in 
accordance  with  the  zig-zag  as  plotted. 

The  explanation  given  so  far  will  un- 
doubtedy  make  clear  the  action  of  the  "elec- 
trical zig-zag"  course  apparatus.  Let  us 
now  consider  one  change  of  the  course  right 
straight  thru  to  see  just  what  happens.  , 

Suppose  the  "zig-zag"  course  is  suddenly 
decided  upon.  The  navigating  officer 
throws  in  the  proper  switches  to  permit 
the  automatic  helmsman  to  take  control  of 
the  ship's  rudder.   The  clock  may  be  turned 


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October,  1917 


THE  ELECTRICAL  EXPERIMENTER 


415 


so  that  the  hour  hand  with  its  attached  con- 
tact is  just  on  the  hour.  The  first  stationary 
contact  is  thus  livened  up,  causing  the  rud- 
der motor  to  function,  and  the  ship  to  take 
its  first  lap  on  the  "zig-zag"  course  or  30 
to  port.  In  order  that  the  helm  motor  shall 
run  just  long  enough  to  throw  the  rudder 

THE  AMATEUR'S  OPPORTUNITY. 

(Continued  from  page  389) 
with  the  November  issue  we  are  going  to 
print  a  monthly  list  of  names  of  those 
young  men  who  think  sufficiently  of  their 
services  to  Uncle  Sam  as  radio  oper- 
ators. 

This  list  will  be  termed  : 

RADIO  ROLL  OF  HONOR. 

At  the  end  of  this  article  you  will  find 
a  blank  to  be  signed  by  you.  Fill  it  out  at 
once  and  mail  it  today.  There  are  no 
charges,  no  expenses. 

Sign  the  blank,  showing  that  you  are  a 
good  citizen  and  that  you  are  prepared  to 
do  your  "bit"  for  your  country.  We  pledge 
ourselves  to  publish  every  name  sent  in  to 
us — even  tho  we  have  to  run  ten  solid  pages 
of  names  a  month. 

You  may  never  be  called  for  service,  but 
in  the  years  to  come  you  will  look  with 
satisfaction  and  pride  upon  the  "Radio  Roll 
of  Honor"  containing  your  name,  in  mute 
testimony  of  your  genuine  patriotism. 

Now  amateurs,  all  together  :  LONG  LIVE 


AMERICA !  LONG  LIVE  WIRELESS! 
to  the  proper  course  angle,  the  stationary 
clock  contact  could  be  made  a  certain  length 
or  else  a  dash-pot  time  switch  can  be  used 
in  the  circuit  to  cut  off  the  motor  after  the 
proper  time  has  elapsed. 

Rut  this  is  not  all  of  the  problem  by  any 
means.  We  can't  leave  the  helm  thrown 
over,  say  30°  to  port,  indefinitely,  or  the 
vessel  would  turn  a  complete  circle.  We 
will  have  to  use  either  an  automatic  time 
relay  to  close  the  opposite  motor  circuit 
and  rectify  the  rudder  to  a  position  parallel 
with  the  ship's  keel,  or  better  yet,  rig  up  a 
special  gyroscopic  compass  so  that  when 
the  ship  has  turned  and  lined  up  on  its 
new  course,  the  compass  will  actuate  a 
relay  controlling  the  opposite  helm  motor 
and  pull  the  rudder  to  its  central  position. 
The  gyroscopic  compass  is  rugged  enough 
to  stand  this  work,  but  it  would  not  be 
necessary  to  fit  any  rubbing  contacts  to  it. 
A  Tesla  relay  would  do  the  work,  the  relay 
current  passing  thru  a  spark,  or  the  proper 
contacts  could  be  closed  by  an  inductm 
mechanism.  The  plans  here  shown  include 
tell-tale  lamp  signals,  which  indicate  the 
course  the  ship  is  changing  to,  and  also 
two  distinct  "zig-zag"  course  charts,  each 
good  for  one  hour's  sailing.  One  course 
is  the  exact  converse  of  the  other,  t.  e.,  the 
first  lap  of  IV2  minutes  on  the  left-hand 
chart  is  run  at  30°  port ;  the  corresponding 
lap  on  the  right-hand  chart  is  run  at  30° 
starboard. 


RADIO  ROLL  OF  HONOR 

Application  for  Membership  in  the 
Radio  League  of  America 

Trr  THE  UNDERSIGNED,  a  Radio  Amateur,  am  the  owner  of  a  Wireless 
^1    Station  described  in  full  in  this  application.    My  station  has  been  in  use 

since  ,  and  I  herewith  desire  to 

apply  for  membership  in  the  RADIO  LEAGUE  OF  AMERICA.  I  will  abide 
by  all  the  rules  of  the  LEAGUE,  and  I  particularly  pledge  my  services  as  a 
Radio  operator,  or  for  Signal  Corps  duty  to  the  United  States  Government 
when  called  upon. 

I  understand  that  this  blank  with  my  signature  will  be  sent  to  the  United 
States  Government  officials  at  Washington,  who  will  make  a  record  of  my  name. 


Witnesses  to  signature : 


Name  

City... 
State. 


Date. 


191 


Description'  off  My  Station  and  Apparatus 


Sending  . 
Receiving 


I  can  send  approximately  words  per  minute. 

1  can  receive  approximately  words  per  minute. 

My  age  is  years. 


(10-17) 


NO  CHARGES.  NO  DUES 

CUT  OUT,  FILL  IN,  AND  RETURN  AT  ONCE 


You  Need  a 

GOOD  PLIER 

A  drop  forged  steel  plier 
shown  here  of  ''RED 
DEVIL"  quality  will  stimu- 
late your  efforts  toward  bet- 
ter work.  Nickel-plated, 
6H  in.  with  combination 
jaws  and  screw  driver  in 
handle.  Style  1024,  sample 
60c.  Circulars  of.  other 
styles  free. 

SMITH  &  HEMENWAY  CO.,  INC, 

107  Coit  Street,  Irvington,  N.  J. 


Big  Money  in  Electricity 

The  electrical  industries  offer  wonderful 
opportunities  to  boys  with  a  liking  for  Elec- 
tricity. The  salaries  paid  to  trained  men  are 
large,  promotion  comes  rapidly  and,  best  of 
all,  the  work  is  fascinating. 

The  discovery  and  development  of  new 
lines  (such  as  wireless  telegraphy  and  tele- 
phory),  from  time  to  time,  promise  attractive 
and  paying  fields  to  those  who  wish  to 
spec  .alize.  The  ivill  to  do  and  Special  Train- 
ing will  bring  success  to  you. 

The  International  Correspondence  Schools 
can  help  you  to  become  an  expert  in  electrical 
work,  no  matter  what  branch  you  like  best. 
Thousands  of  young  men  have  already  won 
success  through  I.  C.  S.  help.  You  can  do 
as  well  as  anybody,  if  you  try.  Everything  is 
made  so  clear  that  you  can  learn  in  your 
spare  time,  regardless  of  where  you  live  or 
what  your  work.    No  books  to  buy. 

There's  big  money  in  Electricity.  Get 
after  it  by  marking  and  mailing  the  Coupon 
today.    Tinding  out  costs  you  nothing. 

I  INTERNATIONAL  CORRESPONDENCE  SCHOOLS 

Box    535  6.SCRANTON,  PA. 

Explain,  without  obligating  me,  how  I  can  qualify  for 
I  the  position,  or  in  tne  subject,  before  which  I  mark  X, 


ELECTRICAL  ENGINEER 
Electrician 
Electric  Wiring 
Electric  Lighting 
Electric  Car  Running 
Heavy  Electric  Traction 
Electrical  Draftsman 
Electric  Machine  Designer 
Telegraph  Expert 
Practical  Telephony 
MECHANICAL  ENGINEER 
Mechanical  Draftsman 
Machine  Shop  Practice 
Gas  Engineer 
CIVIL  ENGINEER 
Surveying  and  Mapping 
MINE  FOREM'N  OR  ENG'R 
Metallurgist  or  Prospector 
STATIONARY  ENGINEER 
ARCHITECT 
Architectural  Draftiraan 
PLUMBING  AND  HEATING 
Sheet  Metal  Worker 


□  CHEMICAL  ENGINEER 

□  SALESMANSHIP 

□  ADVERTISING  MAN 
Q  Window  Trimmer 

□  Show  Card  Writer 

□  Outdoor  Sign  Painter 

□  RAILROADER 

□  ILLUSTRATOR 

□  DESIGNER 

□  BOOKKEEPER 

□  Stenographer  and  Typist 
Z]  Cert.  Pub.  Accountant 
I]  Railway  Accountant 

□  Commercial  Law 

□  GOOD  ENGLISH 

□  Common  School  Subjects 

□  CIVIL  SERVICE 

□  Railway  Mail  Clerk 

□  Textile  Overseer  or  Supt, 

□  AGRICULTURE  Q  Spanl.h 

□  Navigator       Q  German 

□  PonltrvRaising  □  French 

□  Automobiles       □  Italian 


Name_ 


Present 
I  Occupation. 

I  Street 

I  and  No  


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THE  ELECTRICAL  EXPERIMENTER 


October,  1917 


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(FIRING  BOMBS  BY  ELECTRICITY. 

{Continued  from  page  370) 
of  the  cable,  and  this  of  course  is  but  a 
few  ounces.    Even  the  sudden  jerk  after 
releasing  the  bomb  is  not  imparted  to  the 
wire — the  reel  takes  it  nearly  all. 

Now,  the  observer  thru  his  trench  peri- 
scope watches  the  flight  of  the  bomb.  His 
one  hand  rests  on  the  switch  which  is  con- 
nected to  a  thirty-  or  forty-volt  storage 
battery,  while  the  bomb-cable  connects  with 
the  switch  and  the  battery  also.  By  merely 
|  throwing  the  switch,  the  man  at  the  peri- 
scope can  set  off  the  distant  bomb  at  the 
proper  moment.  What  this  proper  moment 
is  depends  of  course  upon  circumstances  as 
well  as  the  will  of  the  operator. 

And  now  we  come  to  the  point  showing 
where  this  device  is  superior  to  the  present 
bomb.  Suppose  during  a  dark  night  we 
throw  several  hundred  of  these  bombs  in 
"no  man's  land"  (the  strip  of  land  between 
our  own  and  the  enemy's  trench).  They 
may  rest  peacefully  here  for  days  or  months 
well  hidden  by  plants  or  dirt.  The  fine 
cables  running  toward  our  own  trench  can 
hardly  be  seen.  The  enemy  therefore  is  un- 
aware of  the  hidden  bombs.  It  goes  with- 
out saying  that  all  the  cables  are  connected 
to  one  central  point  under  supervision  of 
one  or  more  operators.  If  now  the  enemy 
wishes  to  raid  our  trench  we  can  set  off 
the  entire  string  of  bombs  right  under  his 
feet,  as  he  advances  toward  us.  Such  tac- 
tics are  sure  to  demoralize  the  bravest 
troops,  and  the  second  advancing  column 
will  hesitate,  not  knowing  if  there  is  not 
another  set  of  bombs,  which  may  go  off  at 
any  second. 

Of  course,  the  electrically  fired  bomb 
would  probably  be  used  mostly  to  "bomb" 
the  enemy's  trenches,  exploding  it  after  its 
descent  into  the  trench.  And  after  the 
enemy  becomes  acquainted  with  this  devilish 
device,  no  one  will  be  fool  enough  to  pick 
up  such  a  bomb  with  an  idea  to  hurl  it  back 
at  the  sender.  For  the  sender,  thru  his 
periscope,  would  see  it  before  it  vas  two 
feet  above  the  enemy's  trench,  when  he 
would  explode  it  of  course,  thereby  almost 
certainly  killing  the  man  who  attempted  to 
throw  it  back. 

Also,  suppose  that  due  to  faulty  throwing 
the  bomb  does  not  reach  the  enemy  trench. 
Is  the  bomb  thereby  lost  as  is  the  case  with 
its  present  brethren?  Indeed  not!  For  we 
can  pull  it  back  by  meajis  of  the  cable,  and 
throw  it  once  more  ! 

Now  let  us  turn  from  the  murderous 
to  the  more  humane.  Instead  of  filling 
our  bomb  with  a  high  explosive,  let  us  fill 
it  with  chloroform.  Our  Fig.  2  illustrates 
such  a  bomb.  It  is  composed  of  two  hemis- 
pheres separated  by  a  soft  gasket.  After 
partly  filling  the  bomb  with  chloroform, 
the  remaining  air  is  pumped  out,  thus  leav- 
ing a  vacuum.  This  will  cause  the  hemis- 
pheres (working  on  the  famous  "Magde- 
burg Hemispheres"  principle)  to  hold  to- 
gether as  if  riveted.  The  two  ends  of  the 
electric  cable  go  to  a  fusible  plug  in  the 
wall  of  the  bomb  which  when  melted  by  a 
heated  platinum  wire  allows  either  air  or 
chloroform  to  leave  the  bomb.  Or  other- 
wise a  minute  electrically  fired  charge  of 
explosive  will  separate  the  two  hemispheres, 
-n laying  the  trench  with  chloroform.  If  a 
number  of  such  bombs  are  thrown 
trench,  the  occupants  will  promptly 
i  sleep  for  some  time  to  come.  No, 
this  idea  is  not  half  so  ridiculous  as  it 
seems,  and  we  may  see  it  tried  yet. 

If  the  "powers  that  be"  do  not  approve 
of  the  chloroform  bombs,  they  may  replace 
the  narcotic  with  oil.  In  this  way  the  en- 
tire trench  of  the  enemy  can  be  set  on  fire 
when  setting  off  the  bombs. 

Probably  quite  a  few  more  ideas  will 
suggest  themselves  when  the  electrically 
fired  bomb  is  tried  out  in  actual  warfare. 


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October,  1917 


THE  ELECTRICAL  EXPERIMENTER 


417 


MR.  AMATEUR,  "I  WANT  YOU!" 
SAYS  UNCLE  SAM. 

(Continued  from  page  387) 
structors  in  the  following  subjects: 

Magnetism  and  Electricity. 

Alternating  Currents. 

A.  C.  and  D.  C.  Recording  Instruments. 

Primary  and  secondary  batteries. 

Motors,  motor  generators  and  controlling 
devices. 

Gas  and  oil  engines. 

Primary  and  secondary  circuits. 

Oscillating  circuits. 

Transmitting  and  receiving  sets. 

Naval  service  radio  sets  and  operation. 

Wave  meters  and  measurements. 

Radio  regulations  and  fleet  work. 

Instruction  is  also  given  in  drill  work, 
thereby  fitting  the  radio  operator  for  his 
future  duties  as  petty  officer. 

During  the  period  of  training,  men  will 
receive,  in  addition  to  their  regular  pay, 
an  allowance  of  $1.25  per  day  with  which 
to  subsist  themselves. 

Upon  being  called  to  active  service  each 
man  will  receive  a  uniform  gratuity  of 
$60.00. 

Upon  completion  of  three  months'  active 
service  men  may  be  examined,  and  if  found 
competent,  will  be  confirmed  in  their  rat- 
ing. After  such  confirmation  in  addition 
to  their  regular  pay,  they  will  receive  an 
annual  retainer  pay,  equal  to  two  months' 
pay  of  the  corresponding  rate  in  the  Navy, 
same  to  be  paid  quarterly. 

Enrollment  in  the  U.  S.  Naval  Reserve 
Force  is  for  a  period  of  four  years,  but 
in  times  of  peace,  a  man  enrolled  may  be 
discharged  upon  application  to  the  proper 
authority. 

Now,  fellow  "Bugs",  here  is  an  excel- 
lent chance  to  serve  your  country,  at  the 
same  time  enabling  you  to  broaden  your 
education,  build  up  your  physique,  come  in 
contact  with  real  men  doing  real  things, 
save  money,  get  good  wholesome  food  to 
eat,  and  free  medical  attention  when  you 
are  sick. 

A  chance  to  secure  advancement  in  the 
Radio   Profession,   an   invaluable  expen 
ence  acquired  thru  coming  in  contact  with 
up-to-date  methods  and  most  modern  equip- 
ment. 

On  top  of  all  this  you  secure  an  honor- 
able discharge  when  your  enlistment  ex- 
pires from  the  U.  S.  Navy,  which  is  a 
splendid  reference  at  all  times  in  civilian 
life. 

So  its  up  to  you,  Radio  Amateurs,  and 
those  desiring  further  information  should 
present  themselves  to,  or  communicate  with 
the  Enrolling  Officer,  Building  No.  13,  Navy 
Yard,  Brooklyn,  New  York. 


ARE  THERE  CURRENTS  ABOUT  A 
MAGNET? 

(Continued  from  page  381) 
noid,  "F".  At  "G",  at  the  upper  end  of 
the  wooden  lever  "B",  is  attached  a  cord 
which  is  led  across  and  over  the  pulley 
"I"  to  the  scale  pan  and  weight  "K".  With 
"A"  just  at  the  level  of  the  pole  and  in- 
side the  solenoid,  this  solenoid,  with  the 
battery  which  I  used,  will  draw  15.8  grams 
two  centimeters  out  of  perpendicular.  In- 
side, four  centimeters  from  the  pole,  it  will 
draw  25.8  grams— the  additional  weight  be- 
ing placed  at  "K" — the  same  distance ;  an 
increase  of  power  of  sixty-three  percent. 
At  seven  centimeters  within  the  solenoid 
it  will  draw  22.5  grams ;  an  increase  from 
the  poles  of  forty-four  percent.  At  the 
center  of  the  solenoid  the  power  varies 
but  little  from  that  at  the  poles.  (This 
will  be  explained  later.)  If  it  were  pos- 
sible to  investigate  the  interior  field  after 
the  insertion  of  an  iron  core,  it  would 
probably  be  found  that  the  point  of  great- 
est lateral  (outward)  attraction  is  near  the 
center  of  the  magnet. 


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418 


THE  ELECTRICAL  EXPERIMENTER 


October,  1917 


are   constantly    writing  me 
for  new  ideas  protected  by  OWEN  PATENTS. 

Send  for  my  free  literature  and  read  their 
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FRFF  •  Four  finest  Patent  books  published.  73 
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"Patent  Buyers"  Publishes  over  400  letters  from 
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rpon  request. 

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It  is  now  possible  to  map  completely  the 
exterior  and  interior  "lines"  or  currents  of 
a  magnetic  field ;  a  thing  never  heretofore 
truthfully  done.  Those  produced  hereto- 
fore have  been  merely  guesswork.  Fig.  6 
shows  such  a  mapt  field.  A,A,  is  the  point 
of  greatest  compression.  This  point  would 
also  be  the  point  of  the  greatest  interior 
lateral  attraction  if  it  were  not  for  the 
fact  of  the  conflicting  currents  from  the 
poles  meeting  at  this  point.  B,B,  on  both 
sides  of  the  magnet  is  the  neutral  line,  or 
line  of  repulsion,  the  point  of  the  outward 
flowing  currents,  corresponding  to  the 
greatest  internal  pressure.  E,E,  are  the 
points  of  greatest  relative  lateral  attrac- 
tion on  the  interior  of  the  solenoid.  The 
several  lines  C,C,  are  the  reverse  curve 
lines  on  the  side  of  the  magnet  and  the 
lines  D,D,  are  the  slightly  curved  or 
straight  lines  entering  the  magnet  near  the 
poles.  In  all  of  these  the  arrows  indicate 
the  direction  in  which  the  iron  tends  to 
move  and  consequently  the  direction  of 
the  force  or  current.  It  must  be  borne 
in  mind  that  all  of  these  lines  have  an- 
other motion,  that  is — a  spiral  motion,  as 
has  been  shown,  and  that  while  the  spiral 
lines  or  currents  meet  in  the  center  of  the 
magnet,  the  rotation  of  the  spiral  is  con- 
tinuously in  the  same  direction  thruout 
the  length  of  the  magnetic  field. 

These  experiments,  including  the  pro- 
duction of  Magneto-graphs  by  means  of  a 
magnet,  prove  unquestionably  the  following 
negative  facts : 

The  "lines  of  force"  in  a  magnetic  field 
are  not  "lines  of  tension,"  "mere  lines  of 
direction,"  or  "imaginary  lines  of  direction 
like  the  lines  of  latitude  and  longitude  on 
the  earth."  It  will  be  noted  that  these 
expressions  are  quoted  from  high  and  ac- 
cepted authority. 

That  the  lines  of  force  in  a  magnetic 
field  are  not  continuous  from  the  North  to 
the  South  pole,  that  they  do  not  "exist" 
from  the  North  pole  to  the  South  pole, 


BOOK 
ScFOFvM 
EVEPnY 
INVENTOR 
SHOULD 
U5E 


*  ^  ATTORNEYS 

^rkr  Inversions ^Vkirl 

History  will  repeat  itself  in  the  present  War.  The  greatest  victories  will 
be  won,  nut  through  overpowering  numbers,  but  through  the  surprises 
wrought  by  invention.  Life  and  property  will  be  saved  for  the  Nations  by 
inventions.  The  Government  is  ready  to  experiment  with  and  carefully 
consider  any  inventions  which  will  aid  in  winning  and  ending  the  War. 
The  Special  War  Bulletin  just  off  the  press  will  give  you  a  good  idea  of 
what  is  needed.  We  will  send  it  to  you  free  of  charge.  Located  in  Wash- 
ington, we  are  in  close  touch  with  the  proper  Government  Officials  who 
should  be  approached  with  inventions  for  use  in  War  time,  and  we  will 
'  advise  you  fully  how  the  disclosure  should  be  sent. 

Our  cooperation  with  an  inventor  is,  First,  to  help  him  establish  his 
rights  before  sending  a  sketch,  drawing  or  model  to  any  attorney;  Second, 
to  give  a  frank  opinion  whether  it  will  pay  to  patent  his  idea,  based  upon 
our  extensive  knowledge  of  the  patent  laws,  manufacturers'  wants  and 
facilities;  Third,  to  obtain  for  him  on  reasonable  terms,  a  patent  that  abso- 
lutely protects;  and.  Fourth,  advise  and  assist  him  in  making  the  invention 
a  source  of  profit  by  outright  sale,  territorial  grants,  obtaining  royalty,  or 
the  independent  manufacture  of  the  invention. 

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Savings  Bank,  Washington.  D.  C. ;  Duskil  Mop  Co.,  Paducah,  Ken.  :5 

Before  disclosing  the  invention   to  anyone,   sign,   witness  and 
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D.  C. 


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Address 


and  that  they  do  hot  "emerge"  from  the 
North  pole,  or  that  so  far  as  the  lines 
about  the  North  pole  are  concerned  they 
do  not  "pass  to"  or  "enter"  the  South  pole. 

The  same  experiments  seem  to  prove  be- 
yond controversy  the  following  positive 
facts : 

Currents  surround  and  enter  magnets 
and  solenoids  and  make  up  the  field  of 
force  surrounding  them,  and  their  effects 
are  due  to  these  currents.  The  word  "cur- 
rents" is  here  used  and  will  be  continued 
to  be  used  for  the  present  without  refer- 
ence to  the  matter  which  composes  them  ; 
for,  of  course,  currents  must  be  composed 
of  matter.  This  is  done  advisedly,  and  in 
due  time  the  nature  of  the  matter  will 
be  conclusively  proven.  There  can  be  no 
question  but  that  these  are  currents.  A 
child  seeing  straws  moving  about  will  at 
once  tell  you  that  there  is  wind — currents 
— and  indicate  its  direction.  This  is  in  con- 
formity with  every  known  fact  of  physics 
as  shown  in  liquids  and  gases.  The  fact 
is  doubly  confirmed  by  the  Magneto-graphs. 
No  one  except  a  person  seeking  some  mys- 
tic or  mysterious  cause  instead  of  the  plain 
and  simple  laws  of  nature,  would  question 
this  or  assert  otherwise.  Especially  is  this 
true  when,  as  here,  the  motions  are  so 
many  and  so  various,  so  complicated.  No 
"line  of  force',  "line  of  direction",  "ten- 
sion", or  other  mythical  cause  can  account 
for  the  results  shown  in  these  experiments 
and  especially  for  the  production  of  Mag- 
neto-graphs. 

The  action  of  the  electro-magnet,  the 
permanent  magnet,  and  the  solenoid  are 
exactly  the  same,  their  effects  are  the  same, 
and  are  produced  in  the  same  manner, 
and  they  are  governed  by  the  same  laws. 

These  currents  do  not  emerge  from 
either  pole  of  the  magnet.  They  enter 
at  the  poles  and  at  the  sides  of  the  magnet. 
They  emerge  from  the  center  of  the  mag- 
net, to  some  extent  at  least,  and  if  they 
do  not  cause  a  point  of  actual  repulsion, 
they  form  a  line  of  neutrality  in  the  center 
of  the  magnetic  field  and  from  this  neu- 
tral zone,  as  well  as  from  other  surround- 
ing points,  they  move  toward  the  sides  and 
poles  of  the  magnet.  Beginning  at  this 
neutral  zone  they  move  in  opposite  direc- 
tions. 

Currents  entering  the  poles  of  the  mag- 
net meet  at  the  center,  or  near  the  center. 

Currents,  both  inside  and  outside  the 
magnet,  while  they  move  toward  the  center, 
are  spiral  and  the  motion  is  continuous, 
in  the  same  direction,  thruout  the  mag- 
netic field.  The  motion  of  these  spiral 
currents  is  such  that,  viewed  from  above, 
the  rotation  is  counter-clockwise  over  the 
North  pole  and  clock-wise  over  the  South 
pole. 

The  action  of  the  magnet  is  not  due  to 
molecular  arrangement.  Molecular  ar- 
rangement could  in  no  wise  produce  the 
spiral  motion  nor  affect  a  photographic 
plate.  If  the  action  of  the  magnet  were 
due  to  molecular  arrangement,  there  would 
be  no  attraction  at  the  sides  of  the  mag- 
net near  the  poles  for  the  reason  that, 
theoretically,  the  molecules  in  the  body  of 
the  magnet  neutralize  each  other  and  there 
would  be  no  attraction.  Moreover,  when 
the  iron  core  is  removed  the  action  con- 
tinues, being  only  less  in  degree,  due  to 
the  magnetic  conductivity  of  the  iron,  and 
there  are  no  molecules  to  arrange. 

Next  will  be  taken  up  the  nature  and 
cause  of  these  currents,  the  "field  of  force" 
or  the  magnetic  field  about  a  charged  wire, 
and  the  logical  accounting  for  the  forma- 
tion of  a  magnet  and  the  logical  explana- 
tion of  the  several  phenomena  of  magne- 
tism. This  will  include  Magneto-graphs 
produced  by  a  charged  wire. 


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October,  1917 


THE  ELECTRICAL  EXPERIMENTER 


419 


Edited  by  H.  GERNSBACK 

In  this  Department  we  publish  such  matter  as  is  of  interest  to  inventors  and 
particularly  to  those  who  are  in  doubt  as  to  certain  Patent  Phases.  Regular  inquiries 
addrest  to  "Patent  Advice"  cannot  be  answered  by  mail  free  of  charge.  Such  inquiries 
are  publisht  here  for  the  benefit  of  all  readers.  If  the  idea  is  thought  to  be  of  im- 
portance, we  make  it  a  rule  not  to  divulge  details,  in  order  to  protect  the  inventor  as 
far  as  it  is  possible  to  do  so. 

Should  advice  be  desired  by  mail  a  nominal  charge  of  $1.00  is  made  for  each 
question.  Sketches  and  descriptions  must  be  clear  and  explicit.  Only  one  side  of 
sheet  should  be  written  on. 


RADIOMETERS. 

(172.)  Harry  Abrams  of  New  York,  N. 
Y.,  thinks  he  has  a  new  means  of  producing 
electricity  by  means  of  ordinary  sunlight. 
The  idea  is  to  use  apparatus  similar  to 
the  Crookes  radiometer.  By  placing  these 
Crookes  devices  in  a  certain  electrical  field, 
he  has  observed  that  electrical  current  can 
be  generated.  He  wants  to  know  if  this 
idea  is  practical  and  also  patentable. 

A.  We  have  strong  doubts  as  to  the 
practicability  of  an  idea  of  this  kind.  It 
seems  that  the  power  that  can  be  obtained 
from  each  one  of  these  radiometers  would 
be  so  infinitesimally  small,  that  it  really 
could  not  be  termed  power;  but  at  best 
would  only  be  faint  impulses.  We  doubt 
if  the  idea  has  any  commercial  possibili- 
ties. 


GYROSCOPIC  AUTOMOBILE. 

(173.)  Frank  C.  Stanton  of  San  Fran- 
cisco, Cal.,  has  submitted  to  us  an  elaborate 
illustration  of  a  gyroscopic  motor  car, 
showing  an  automobile  designed  to  run  on 
two  wheels,  one  behind  the  other.  He 
wishes  to  know  if  he  can  obtain  a  patent 
on  this  device  without  litigation. 

A.  Brennan  of  England  has  experi- 
mented with  a  car  of  this  kind,  having  it 
run  over  a  small,  thin  cable.  We  doubt 
if  you  can  obtain  a  patent  that  would  be 
of  any  value  to  you,  in  view  of  the  fact 
that  not  alone  Brennan,  but  also  other 
workers  as  well  have  worked  along  these 
same  lines  for  quite  some  time  past.  Our 
correspondent  also  submits  illustration  for 
a  field  wireless  set  which  can  be  carried 
complete  by  one  man,  and  he  wishes  to 
know  if  the  idea  is  feasible  and  practical. 

Nothing  new  is  shown  in  the  illustration 
or  description,  and  while  the  disposition 
does  show  several  novel  points,  we  doubt 
very  much  if  the  novelty  is  sufficient  to 
warrant  a  patent. 

Our  correspondent  wants  to  know  if  one 
has  to  be  a  subscriber  to  The  Electrical 
Experimenter  in  order  to  contribute  to  any 
of  the  various  departments. 

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menter, and  one  need  not  be  a  subscriber 
in  order  to  send  any  contributions  or 
participate  in  any  of  the  prize  contests 
which  we  conduct  from  time  to  time. 


AUTOMATIC  STEP-LADDER. 

(174.)  Paul  William  Dorst  of  New  Al- 
bany, Ind.,  submits  to  us  an  automatic  step 
to  be  attached  to  hollow  steel  flag-poles, 
the  idea  being  that  the  steps  are  folded 
back  ordinarily,  so  that  when  climbing  the 
pole  one  step  after  the  other  is  released 
automatically  as  soon  as  one  of  the  steps 
is  deprest. 

A.  This  is  a  capital  idea,  and  we  have 
not  seen  anything  quite  like  it,  and  are  cer- 
tain that  it  can  be  patented.  We  also  think 
that  there  should  be  a  good  field  for  a 


device  of  this  kind,  particularly  for  steel 
flag-poles  on  tall  buildings. 


CONDENSER. 

(175.)  H.  S.  Moody  of  Edmonton,  Alta., 
has  an  idea  to  make  a  small  condenser  in 
a  certain  manner  by  using  certain  dry 
mounting  tissues,  etc.  Several  other  means 
are  shown  to  hold  metal  foils  which  are 
secured  by  melting  the  tissue.  He  wishes 
to  know  if  an  idea  of  this  kind  is  patent- 
able. 

A.  Without  making  a  thoro  search  in 
the  patent  office,  we  are  unable  to  tell 
whether  this  idea  is  of  sufficient  originality 
to  warrant  patenting.  We  would  advise  to 
have  a  patent  attorney  make  search  with 
a  view  to  ascertaining  what  has  been  done 
in  the  same  field  before.  The  idea  seems 
quite  clever. 


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THE  ELECTRICAL  EXPERIMENTER 


October,  1917 


I  was  very  much  pleased  with  the  neat  and 
compact  looks  of  the  "RADIOTONE."  I  have 
not  seen  one  buzzer  that  can  beat  it  for  twice 
or  THREE  TIMES  THE  PRICE.  I  use  it  for 
finding  the  sensitive  part  of  the  mineral  in  my 
crystal  deteeter  and  for  learning  to  receive  mes- 
sages when  connected  with  one  or  more  receivers, 
and  a  telegraph  key  to  break  the  circuit.  I  also 
wish  to  say  that  I  think  that  any  one  who  in- 
vests !)0c  in  a  "RADIOTONE"  will  be  better 
pleased  with  the  results  in  the  short  as  well  as 
long  run  than  any  other  buzzer  that  costs  twice 
Hie  price. 

PRIVATE  P.  H.  RUMPEL.  4th  Co..  C.  A.  C. 

U.  S.  ARMY,  Ft.  Roseerans,  Calif. 


I  wish  to  say  that  your  "RADIOTONE"  Buz- 
zer works  better  than  I  ever  thought  it  would, 
and  I  don't  think  there  is  a  BETTER  BUZZER 
ON  THE  MARKET.  It  also  gives  a  very  classy 
appearance  to  any  wireless  outfit.  It  cannot  be 
praised  too  highly. 

PERRY  CRAWFORD, 
13  Ten  Broeck  St.,  Albany,  N.  T. 


I  liavo  given  vour  "RADIOTONE"  Buzzer  o 
thoro  test  and  find  it  to  give  VERY  GOOD  SAT- 
ISFACTION. Also  that  I  am  very  much  pleased 
with  it  and  that  it  comes  up  to  my  expectations. 
I  would  recommend  it  to  all  learners  as  a  very 
good  Buzzer.  In  case  I  have  any  more  orders 
I  will  extend  them  to  you. 

W.  H.  CRDDGINGTON, 
TJ.  S.  S.  UTAH.  Box  E,  care  of  P.  M.,  N.  Y. 


I  received  my  "RADIOTONE"  Buzzer  a  few 
clavs  ago.  and  have  tried  it  out  in  a  number  of 
ways.  It  is  exactly  like  you  describe  it,  and  one 
of  the  biggest  advantages  of  it  is  that  the  sound 
is  always  EXACTLY  WHERE  YOU  WANT  IT. 
right  In  the  receivers.  It  is  by  far  the  best  buz- 
zer I  have  seen  on  the  market.  It  has  also  a 
Verv  beautiful  appearance,  and  has  one  of  the 
CLEAREST  AND  HIGHEST  PITCHED  TONES 
any  buzzer  that  I  have  yet  come  across.  Thank- 
ing you  again  for  your  wonderful  buzzer,  I  am, 
Yours  very  truly. 

HOWARD  A.  PAGE. 
800  Harrison  St.,  Lynchburg,  Ya. 


Your  "RADIOTONE"  Buzzer  certainly  came 
up  to  all  my  expectations.  Its  tone  is  exactly 
like  that  heard  in  a  regular  wireless  phone.  It 
is  not  affected  by  high  altitude  nor  damp 
weather.  It  is  as  beautiful  an  instrument  as  one 
could  wish  to  see.  IT  IS  SILENT.  That  is 
the  most  important  of  all  in  the  work  for  which 
I  use  it.  It  produces  a  clearer  and  higher- 
pitched  tone  on  less  current  than  a  buzzer  of 
any  other  make  that  I  have  tried.  IT  HAS 
NEVER  STUCK  nor  FAILED  TO  RESPOND 
instantly  to  the  application  of  current  since  I 
have  had  it.  I  wish  you  and  the  E.  I.  Co. 
every  success  and  I  will  do  everything  in  my 
power  to  help  you  as  you  are  a  PROMPT  AND 
SQUARE  DEALING  COMPANY. 

O.  M.  MeBURNEY, 
Fort  Bayard,  N.  Mex. 


I  wish  to  say  that  your  "RADIOTONE"  Buz- 
zer is  the  only  test  buzzer  that  I  have  seen  in 
Which  I  can  find  NO  fault  whatever.  I  re- 
ceived it  in  good  condition  and  it  is  that  wav 
now.  THOUGH  I  ACCIDENTALLY  DROPPED 
IT  SEVERAL  FEET.  I  am  using  it.  on  a  code 
practicing  set.  It  has  the  best  tone  of  any 
buzzer  that  I  have  seen. 

LESTER  SHIPLEY, 
Care  of  .7.  O.  Tate  Electric  Co. 
118  Main  St.,  Bedford,  Ya. 


I  have  given  the  "RADIOTONE"  Buzzer 
which  I  have  received  from  the  E.  I.  Co.  a 
thoro  test  and  find  it  satisfactory  in  all  re- 
spects. I  also  used  other  buz~ers,  but  the 
"RADIOTONE"  IS  THE  BEST  THAT  I  HAVE 
EVER  LTSED  and  BEYOND  MY  EXPECTA- 
TIONS. The  other  goods  that  I  received  are  also 
satisfactory. 

A.  WITMER. 
Muir,  Pa. 


I  am  very  pleased  to  say  that  I  am  satisfied 
With  the  results  obtained  from  the  "RADIO- 
TONE" Bu-zer.  It  rives  a  reaHv  WONDER- 
FUL IMITATION  OF  A  WIRELESS  MES- 
SAGE. GEORGE  DTMON 

Lavallette.  N.  J. 


ELECTRO    IMPORTING  CO. 

231  Fulton  Street  New  York  City 


FROM  A   RADIO  EXPERT 
The  "RADIOTONE"  Buzzer  which  the  E.  I.  Co.  sent  me  some 
ti me  ago  has  been  thoro  ty  tested  out  in  my  Laboratory,  and  I 
am   very  pleased   to   give  you   my  opinion   concerning   its  per- 
formance. 

The  tone  and  frequency  of  the  instrument  is  TRULY  A  MOST 
WONDERFUL  and  perfect  reproduction  of  a  MUSICAL  WIRE- 
LESS NOTE  and  when  used  in  connection  with  a  wireless  re- 
ceiver it  would  be  most  difficult  to  distinguish  its  rich  tone  from 
that  of  a  real  wireless  station  with  FIVE  HUNDRED  CYCLES 
in  the  primary  circuit.  One  of  the  most  commendable  features 
that  the  buzzer  possesses  is  that  of  being  capable  of  standing  up 
under  continuous  service  WITHOUT  THE  ANNOYING  "STICK- 
ING" effect  that  has  been  so  characteristic  of  other  buzzers  that 
I  have  had  occasion  to  test.  In  conclusion  I  can  say  that  both 
in  performance  and  appearance  the  "RADIOTONE"  Is  truly  a 
WONDERFUL  LITTLE  INSTRUMENT.  RAYMOND  FRANCIS 
YATES,  815  Niagara  Ave.,  Niagara  Falls,  N.  Y. 


No.  Hl<  1800 

The  "Electro"  Radiotone 

HIGH    FREQUENCY    SILENT    TEST  BUZZER 

The  RADIOTONE  is  NOT  a  mere  test  buzzer, 
it  is  infinitely  more.  Mr.  H.  Gernsback  who  de- 
signed this  instrument  labored  incessantly  to 
produce  an  instrument  which  would  imitate  the 
sound  of  a  high  power  Wireless  station  as  heard 
set  of  phones.  This  actually  has  been 
achieved  in  the  KADIOTONE.  This  instrument 
gives  a  wonderful  high  pitched  MUSICAL  NOTE 
the  receivers,  impossible  to  obtain  with  the 
ordinary  test  buzzer.  The  KADIOTONE  is  built 
ilong  entirely  new  lines;  it  is  NOT  an  ordinary 
buzzer,  reconstructed  in  some  manner.  The 
RADIOTONE  has  a  single  fine  steel  reed  vibrat- 
ing at  a  remarkably  high  speed,  adjusted  to  Its 
most  efficient  frequency  at  the  factory.  Hard 
silver  contacts  are  used  to  make  the  instrument 
last  practically  forever. 

Yes,  the  RADIOTONE  is  SILENT.  In  fact, 
it  is  so  silent  that  you  must  place  your  ear  on 
top  of  it  to  hear  its  beautiful  musical  note. 

You  will  be  astounded  at  the  wonderfully  clear, 
500  cycle  note,  sounding  sharply  in  your  re- 
ceivers, when  operated  on  one  dry  cell.  To  learn 
the  codes,  there  is  absolutely  nothing  like  it. 
With  the  radiotone.  a  key  and  one  dry  cell  and 
ANY  telephone,  a  fine  learner's  set  is  had.  Two 
or  more  such  sets  in  series  will  afford  no  end  of 
pleasure  for  intercommunication  work.  Particu- 
larly now  that  we  cannot  use  our  Wireless  sets, 
the  Radiotone  is  already  in  wonderful  demand. 
All  the  interesting  things  as  described  with  our 
CODOPHONE  (see  our  big  ad  on  page  353, 
this  issue),  can  be  performed  with  the  Radio- 
tone,  a  key,  a  dry  cell  and  a  phone. 

Radiotone  as  described  each  ^  90 


I  have  thoroly  tested  your  "KADIOTONE" 
Buzzer,  which  I  received  a  few  days  ago,  and 
find  that  it  is  very  efficient  in  all  respects.  It 
is  all  that  you  claim  it  to  be.  The  tone  is  so 
soft  that  it  cannot  be  heard  unless  the  ear  is 
placed  a  few  inches  from  the  instrument.  This 
makes  it  very  desirable  for  testing  detectors.  I 
THINK  THAT  THERE  IS  NOTHING  BETTER 
FOR  LEARNING  THE  CODE,  since  the  sig- 
nals sound  just  like  a  high  power  wireless  sta- 
tion. Everyone  who  has  a  wireless  station  or 
who  wishes  to  learn  the  code  should  have  3i 
"RADIOTONE."    BENNIE  GREENSTEIN, 

827-llth  Ave.,  N.,  Minneapolis,  Minn. 


I  received  your  "RADIOTONE"  on  June  20th, 
and  tested  it  thoroly.  and  found  it  has  the 
BEST  IMITATION  OF  WIRELESS  SIGNALS. 
All  Amateurs  should  purchase  one  of  these 
"RADIOTONES"  if  possible,  and  do  self-prac- 
tise during  the  war.  I  hope  all  Amateurs,  who 
purchase  one  of  these  "RADIOTONES"  will  find 
it  as  great  a  help  to  them  as  I  have. 

Yours   truly,  GEO.  TANAKA, 

AMATEUR  6  ATQ,  San  Francisco,  Cal. 


After  testing  the  "RADIOTONE"  I  am 
pleased  to  say  that  it  is  the  best  toned  buzzer 
on  the  market.  The  main  thing  is  that  IT 
DOES  NOT  STICK  as  so  many  others  do,  even 
among  the  high  priced  buzzers,  when  prac- 
tising. I  am  using  it  with  Omnigraph  trans- 
mitter, 2  M.F.  Condenser.  75  Ohm  phone  and 
small  resistance  shunt  across  phone.  With  the 
aid  of  battery  rheostat  and  shunt  resistance,  I 
CAN  OBTAIN  EXACTLY  SAME  PITCH  AS 
N.A.A.  FRANK  WARMINSKI, 

8  06  S.  Milton  Ave.,  Baltimore,  Md. 


I  am  entirely  satisfied  with  the  "RADIO- 
TONE"  Buzzer  which  I  bought  from  you.  It 
works  fine,  being  BETTER  THAN  I  EXPECTED 
IT  WOULD  BE  AT  THE  PRICE.  At  first  I 
didn't  think  that  it  would  be  very  good  at 
the  low  price,  but  it  is  all  right.  It  appeals 
to  me  mostly  because  of  ITS  QUICK  RE- 
SPONSE to  the  opening  and  closing  of  the 
key.  JOHN  B.  MOORE. 

Delaware  Co.,  DownsvilTe. 


I  am  pieased  to  say  that  after  testing  it  out 
in  a  student's  buzzer  set,  it  comes  up  to  my 
best  expectations.         H.  D.  STRAUGHN, 

Ripley,  Okla. 


Am  in  possession  of  one  of  your  "RADIO- 
TONE"  test  buzzers  and  wish  to  say  that  I 
could  not  have  expected  a  more  silent  instru- 
ment, as  well  as  the  EXACT  TONE  OF  A 
HIGH   POWERED    WIRELESS  STATION. 

S.   W.  DEARING, 
R.2,    Covington,  Tenn. 


It  gives  me  great  pleasure  to  recommend  your 
"RADIOTONE"  test  buzzer.  I  find  it  very 
sensitive  and  responsive,  ALWAYS  EMITTING 
THE  SAME  HIGH  PITCHED  NOTE.  But 
the  best  feature  of  all  is  ITS  SOUND-PROOi.' 
CASE.  C.  A.  W.  McMURTRY, 

9  4  Gladstone  Ave.,  St.  Thomas,  Ont. 


I  wish  to  say  that  I  have  given  your  "RADIO- 
TONE"  Buzztr  a  thorough  testing  and  find  it 
stands  up  beautifully  under  the  conditions.  Con- 
nected to  a  7  5  ohm  phone  and  a  No.  10010 
Junior  Fixed  Condenser  per  diagram  in  your 
catalogue,  it.  makes  an  ideal  practise  set,  the 
note  of  which  can  HARDLY  BE  DISTIN- 
GUISHED FROM  "ARLINGTON."  The 
"RADIOTONE"  lias  EXCEEDED  MY  EXPEC- 
TATIONS by  far.  E.  A.  ARMSTRONG, 
R.  R.  No.  1,  Indian  River,  Ontario,  Can. 


I  have  used  your  "RADIOTONE"  Buzzer, 
and  find  it  THE  BEST  EVER  USED.  I  find 
it  very  useful  for  a  layman  to  learn  the  code 
quickly.  I  would  recommend  it  to  any  one 
interested   in  wireless. 

ANDREW  SCHRINER, 
r722  Putnam  Ave.,  Brooklyn,  N.  Y. 


I  have  had  the  opportunity  of  making  prac- 
tical tests  with  one  of  your  "RADIOTONE" 
BUZZERS,  and  I  feel  justified  in  making  the 
following    statements    concerning  it: 

1.  It  is   handsome   in  appearance, 

2.  It  is  practically  noiseless  in  operation. 

3.  It  gives  a  clear  note  of  CONSTANT  FRE- 
QUENCY, 

It  is  equal  in  performance  to  other  buzzers 
selling  AT  SEVERAL  TIMES  ITS 
COST. 

_    have    been    perfectly    satisfied     with  the 
'RADIOTONE"  and  I  will  be  glad  to  recom- 
mend it  to  anyone.  E.   K.  SNYDER, 
717  Lake  Boulevard,  St.  Joseph,  Mich. 


E.  I.  Co.,  231  Fulton  St.,  New  York  City,  N.  Y. 

On  your  absolute  guarantee  that  vour  "RADIOTONE"  works  exactly  as  de- 
scribed by  you,  I  enclose  herewith  90  cents  plus    cents  for 

postage  for  one  instrument.  You  guarantee  to  refund  this  amount  to  me  if  I 
am  not  entirely  pleased,  providing  I  return  the  "RADIOTONE"  within  3  days 
after  its  receipt.  YES 

I  also  enclose  NO  6  cents  postage  for  vour  200-page  Electrical  Cyclo- 
pedia, with  600  illustrations,  and  500  instruments,  etc. 

Name   

Address   

10-17  City   


You  benefit  by  mentioning  "The  Electrical  Experimenter"  when  writing  to  advertisers. 


October,  1917 


THE  ELECTRICAL  EXPERIMENTER 


421 


NEW  ELECTRO-THERAPEUTIC 
APPARATUS. 

(Continued  from  page  373) 
Sinusoidal  Machines 
One  of  the  most  radical  new  develop- 


Fig.  3.    The  Latest  Pattern  Sinusoidal  Generator  Which 
Yields   Currents  of  Any   Desired   Wave   Form.  Special 
Cams  as  Shown  Below,  Control  This  Factor  and  Can  be 
Interchanged  Instantly. 


ments  in  electrical  therapeutics  was  shown 
in  the  form  of  a  Morse  Sinusoidal  Wave 
Generator.  The  machine  delivers  a  current 
of  21,000  alternations  or  42,000  impulses 
per  minute  and  is  designed  on  what  is 
known  as  the  Kennelly  design,  the  prin- 
ciple being  a  circular  layer  of  spools  com- 
posed of  two  separate  coils,  an  inner  one 
with  eight  layers  of  fine  wire,  and  an  outer 
one  of  two  layers  of  coarse  wire,  the  inner 
coil  being  connected  in  a  series  and  consti- 
tuting a  secondary  coil,  while  the  outer 
coil,  also  connected  in  a  series,  forms  the 
primary  coil  of  the  apparatus.  A  direct 
current  is  supplied  to  the  primary  coil  and 
to  the  armature,  which  is  composed  of 
laminated  iron.  When  the  armature  is 
made  to  revolve  the  primary  coils,  having 
a  current  circulating  thru  them,  mag- 
netizes the  field  magnets.  The  magnetic 
lines  of  force  thus  produced  remain  sta- 
tionary in  the  field  as  long  as  the  armature 
is  stationary,  but  as  soon  as  the  armature 
rotates  the  lines  of  force  shift  from  one 
side  of  the  magnetic  field  to  the  other  and 
cut  the  current  in  the  wires  of  the  sec- 
ondary coil,  first  one  side  and  then  the 


Sofia 'tuoqsfe/f 
Tu/7gs/&?  sp/ra/ 


r3= 


Mo/yMenam 
_ 


Rod/o/ffy  vows 


sum 


wm 


//O  V 


Transf 
f/gl 


New  Form  of  X-Ray  Tube  Which  Rectifies 
Its  Own  Current,  on  the  Principle  of  the  Hot 
Cathode.    Air  Cooling  Vanes  Are  Placed  on 
the  Anode. 

other,  which  produces  a  Sinusoidal  current 
in  the  secondary  coil. 

In  the  apparatus  shown,  Fig.  3,  the  pri- 
mary coil  and  secondary  coil  are  conical  in 


shape,  one  moving  within  the  other,  this 
being  done  by  a  set  of  cams,  the  shape  of 
the  cam  regulating  the  type  of  wave  which 
will  be  sent  into  the  patient's  circuit,  and  a 
separate  rheostat  controls  the  strength  of 
this  current. 

Light  Therapy 
For  the  treatment  of  skin 
diseases  a  quartz  mercury  arc 
lamp  was  shown  which  gave 
off  very  powerful  radiations, 
the  radiations  being  so  intense 
that  the  darkest  kind  of  tinted 
glasses  were  loaned  to  the  ob- 
server before  he  was  allowed 
to  look  at  the  light.  From  a 
lamp  of  this  kind  a  typical  case 
of  sunburn  could  be  produced 
in  a  few  minutes  time.  (See 
Fig.  4.) 

Miscellaneous 

A  valuable  Anesthetizing 
Outfit  was  shown  (see  Fig.  5), 
operated  by  a  small  electric 
motor  of  special  design  for  use 
in  operations  of  the  month 
and  head. 
An  interesting  Recording 
was  shown  for  obtaining 
perature  within  the  stomach 
intragastric  temperature,  valuable  in 
checking  up  the  gastric  response  to  stimu- 
lus, showing  the  action  of  different  foods, 
both  hot  and  cold,  practically  in  degrees 
upon  the  scale  of  the  instrument. 

For  the  man  with  a  microscope  there 
were  several  new  devices,  such  as  a  special 
light  for  illuminating  the  stage  of  a  micro- 
scope, and  one  exhibit  showed  an  electri- 
cally heated  warm  stage  for  the  microscope 
for  use  in  examining  different  bacteria  and 
micro-organisms  which  only  remain  alive 
in  warm  temperatures  (blood  heat). 

An  Electric  Incubator  for  use  in  connec- 
tion with  a  microscope  was  exhibited,  which 
can  also  be  used  in  connection  with  the 
development  of  special  animal  organisms 
and  bacteria  so  that  they  can  be  cultivated 
directly  under  the  microscope. 


Instrument 
the  tem- 
known  as 


THE  EFFECT  OF  ULTRA-VIOLET 
RAYS  ON  MILK  AND  OTHER 
ASPECTS. 

(Continued  from  page  383) 

it  for  the  protection  of  their  soldiers  and 
horses  campaigning  at  this  time  in  the 
colonies  of  Toncken,  Asia,  and  as  it  had 
protected  the  head  against  the  violent  ac- 
tion of  the  ultra  violet  rays  it  was  quite 
successful.  .>. 

At  this  time  England  also  tried  this  pro- 
tection against  the  ultra  violet  rays  and  as 
an  experiment,  an  under  officer  of  the  Eng- 
lish army  was  completely  clothed  in  gar- 
ments which  had  been  previously  treated 
to  withstand  the  ultra  violet  rays.  It  was 
found  that  he  was  able  to  stay  in  the  sun 
of  midsummer  for  hours,  without  feeling 
any  disturbance  or  inconvenience  in  any 
way.  Upon  this  and  other  experiments  the 
English  Government  adopted  this  method 
for  the  protection  of  their  Indian  troops 
against  the  ravages  of  tropical  sunlight. 


INCREASE  WIRELESS  GUARD  AT 
SAYVILLE. 

Fifteen  United  States  Marines  have  been 
added  to  the  detail  which  has  been  guard- 
ing the  wireless  station  at  Sayville.  There 
are  now  sixty-five  men  from  the  Marine 
Corps  at  the  station  and  it  is  said  that 
about  twenty-five  more  will  arrive  shortly 
to  augment  the  force.  Ensign  W.  R.  Smith, 
U.  S.  N.  R.,  is  in  command. 

The  entire  acreage  belonging  to  the  At- 
lantic Communication  Company,  which  is  in 
charge  of  the  plant,  is  being  cleaned  up. 
Much  of  its  area  was  wooded  and  afforded 
cover. 


Build  a  Model  of  this  Curtiss  MM. 
rii  Tractor  used  in  the  U.S.  Army 


Build  A 


Model  War  Aeroplane! 

It's  fatty!  With  "IDEAL"  Accurate  Scale  Drawings  and 
InstructioriH  you  ran  bnil.i  a.'J  f.»,t  Mod*- 1  Aeroplane  that  looks 
like  a  n  al  or.,.-  an. I  that  will  rise  from  the  ground  by  its  own 
power  and  fly  50  to  1(J0  feet.  It 'strreat summer  sport,  and  you 
can  learn  a  lot  ah. mt  A.-r -opIaneH  and  how  they  fly.  Send  for 
the  Drawings  and  Instructions  for  the  one  you  want  to  build. 


Curtiss  Military  Tractor 
Bleriot  Monoplane 
Nieuport  Monoplane 
Taube  Monoplane 

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Outfits, 


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-se  Aeroplanes,  are  knI.I  by  Leading 

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Ask  your  dealer  for  "IDEAL"  Aeroplan 

Construction  Outfits. 

Send  5c  For  This  Catalogue 

Tells  about  Model  A 


Informatii 


>plan  s  and  what  you 
h.  48  pages  of  useful 
nts  f  oj  it  right  away. 


IDEAL  AEROPLANE  &  SUPPLY  CO., 

76-S2  West  Broadway,  New  York 


Driver  Agents  Wanted 


Drive  and  demonstrate  the  Bush  Car.  Pay  for  It  out  or 
your  commissions  on  sales.  My  agents  are  ™r"°£^S: 

ri»e.Pass.,34.7H.P.y  f  38x35*  tires   Bush^Cars  ^ar- 

back.  1918  modelB 

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my  48-pago  cata- 
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_    iWheelbase^  ■*   H.  Bush,  Pres. 

Delco  Ignition— Elect.  Ste.  &Ltg.        Dept.  irj-ll  > 
BTJSII  moiott  toill'AN V.  Bosh  Temple.  Chicago,  IMnola 


TOOLS 


For  shop,  factory, 
garage  and  home 
— many  high  class 
tools  attractively  priced  in  our  Odds  and 
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quest by 

Montgomery  &  Co.,  Inc.,  105  Fulton  St.,  N.  Y.  Chy 


Feldman  "Geyser" 
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1514  Times  Bldg.  New  York  City 


Edison  Says: — 


"  I  have  watched  the  prog* 
re  83  of  the  International 
Correspondence  Schools 
almost  from  the  beginning. 
To  me  their  rapid  growth  is 
easily  understood  because  I 
realize  the  practical  value 
that  is  back  of  ft  and  know 
something,  too,  of  the  suc- 
cess attained  by  many  am* 
bitious  men  who  have  taken 
I.  C.  S.  courses." 

Edison  knows  what  stuff  men  are  made  of 
who  use  their  spare  hours  to  train  themselves 
for  the  bigger  jobs  ahead.  And  he  knows 
what  the  International  Correspondence 
Schools  will  do  for  the  man  with  the  grit  to 
say,  "I  will."  ' 

All  men  who  have  made  their  mark  in  the 
world  improved  their  spare  time.  Didn't 
Edison  himself  stay  up  half  the  night  to  read 
every  get-at-able  book  on  electricity?  You, 
too,  can  possess  power,  money  and  happiness 
if  you'll  only  make  the  start.  With  I.  C.  S. 
help  the  way  is  easy. 

Put  it  up  to  us,  without  paying  or  promising 
—just  mark  and  mail  the  coupon  and  find  out. 

_    ,  — —    TEAR  OUT    HERE   ■  ■  -—  _ 

INTERNATIONAL  CORRESPONDENCE  SCHCOLS,  Box  5358.  Scranton,  Pa. 
Explain  fully  about  your  Course  in  the  subject  marked  X: 


□  Electrical  En 
3  Mechanical  Engineering 
^Mechanical  Drafting 
UCivil  Engineering 

S Stationary  Engineering 
Mining  Engineering 
n  Architecture 
J  Architectural  Drafting 

Name  


□  ADVERTISING 

□  Salesmanship 

□  Commerchil  La* 

□  Bookkeeping 

□  Stenography 

□  Civil  Service 

□  Ry.  Mail  Service 

□  AUTOMOBILES 


QCHEM1STET 

□  Illustrating 

□  Farming 

□  Poultry 

□  French 

□  German 

□  Italian 

□  SPANISH 


Address- 


You  benefit  by  mentioning  "The  Electrical  Experimenter"  when  writing  to  advertisers. 


422 


THE  ELECTRICAL  EXPERIMENTER 


October,  1917 


KNAPg 

For  Boys 


Dynamo 
Motor 

$/?25 


For  producing  current  for  in- 
ductance coils,  re-charging 
storage  batteries,  elec- 
troplating and  hun- 
dreds of  other  uses. 
Well  constructed 
throughout.exception- 
ally  smooth  running 
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AT  ALL  LIVE  ."DEALERS 

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— KNAPP  goods  are  best.  If  your  dealer  cannot 
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Motors  and  Novelties  ranging  in  price  from, 10c  up. 

KNAPP^ELECTRIC  &  NOVELTY  CO. 

,523  West  51st,Street,  N.  Y.  City 


WOULD  THE  WW  LET  YOU  MARRY? 

Some  States  have  been  vtise  enough  to  Insist  upon  » 

medical  examination  of  the  two  contracting  parties  to  s 
marriage  before  a  license  is  issued.  Through  the  adop- 
tion of  a  law  whereby  the  physically  unfit  were  barred 
from  marriage  in  every  State  in  the  Union,  there  would 
indeed  be  a  relatively  small  percentage  of  the  popula- 
tion that  would  measure  up  to  the  standard. 

WOULD  YOU  BE  ONE  OF  THOSE 
doomed  to  go  through  life  alone,  without  the  Joys  that 
go  hand  in  hand  with  a  loving  wife  and  healthy  chil- 
dren? Our  first  duty  Is  to  posterity.  We  are  not  put 
here  by  an  all-wise  Providence  merely  to  live  out  our 
lives,  and  then  go  out  like  a  snuffed  candle.  We  ars 
entrusted  with  the  sacred  duty  of  perpetuating  the  race. 
LIKE  BEGETS  LIKE:  A  man  who  is  torn  and  racked 
by  physical  ailments  and  excesses  sf 
all  kinds  will  some  day  see  these  traits 
in  his  children.  On  the  other  hand 
the  strong,  virile  man,  who  Jealously 
safeguards  his  body  and  his  health, 
will  some  day  revel  in  the  sight  of 
offspring  that  are  a  picture  of  Joysns, 
bubbling  health. 

YOU  OWE  IT  MOST  TO  THAT  GIRL 

The  sweetest,  purest,  dearest  girl  in 
the  whole  world  whom  you  would  call 
wife.  Is  your  body  clean?  Do  you 
realize  the  terrible  consequences  of 
the  follies  that  are  wrecking  your 
body?  Remember  then  that  STRONG- 
FORT  ISM  will  restore  to  you  the  vi- 
tality of  MANHOOD. 

I  have  prepared  a  little  book.  "Intelligence 
In  Physical  and  Health  Culture,"  which 
should  be  read  by  everyone  sufficiently  Inter- 
ested in  themselves  to  wish  for  the  best  In 
life.  It  points  the  way  to  better  health,  a 
cleaner,  happier  life,  and  a  splendid  physique. 
Three  2-cent  stamps  will  pay  for  mailing  the 
book.    Send  for  it  NOW. 

LIONEL  SIROUGfORr,  Master  of  Physical  Culture 

276  Park  Building  Newark,  N.  J. 


a  Month 

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The  great  Burlinrrton  Watch  sent  on  simple  request. 
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Built  by  a  boy  from  Junior  parts  fur- 
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car.  Parts  very  cheap.  Send  26 
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of  parts  showing  how  to  build  this 
speedy  little  car. 


RADIO  TO  HURL  MINES  AT 
U-BOATS. 

After  working  for  many  months  to  per- 
fect a  new  type  of  mine,  electrically  con- 
trolled by  means  of  a  powerful  wireless 
apparatus  located  at  a  distance  from  the 
mine  itself,  a  device  which  would  enable 
one  submarine  to  destroy  another,  it  was 
learned  recently  that  Dr.  J.  B.  Whitehead, 
of  the  Johns  Hopkins  University,  had 
brought  his  labors  to  a  successful  termina- 
tion. 

While  Doctor  Whitehead  refuses  to  com- 
ment on  this  new  invention,  it  is  learned 
that  by  means  of  a  powerful  electric  bat- 
tery the  new  style  of  mine  can  be  directed 
upon  whatever  course  its  operator  may  de- 
sire and  can  be  exploded  by  simply  press- 
ing a  button,  the  wireless  waves  being  em- 
ployed both  in  directing  it  and  in  its 
explosion. 

The  advantage  that  such  a  mine  will  have 
over  the  ordinary  torpedo  used  by  the  sub- 
marine is  the  impossibility  of  failure  to 
either  miss  the  target  or  its  non-explosion 
after  the  target  is  struck.  By  this  method 
Doctor  Whitehead  has  solved  the  problem 
of  destroying  submarines  by  submarines. 
In  connection  with  this  is  a  report  that  an 
instrument  has  been  perfected  to  locate 
positions  and  distances  of  the  submarine  to 

be  attacked.  

FREE  ELECTRICITY  FROM  THE 
WIND. 
{Continued  from  page  372) 

The  invention  of  this  new  slow  speed 
design  at  once  eliminates  the  gear  troubles 
which  all  others  who  have  attempted  to 
utilize  wind-power  to  drive  dynamos  have 
had  to  employ.  It  also  makes  it  possible 
to  effect,  by  magnetic  leakage  in  the  ma- 
chine itself,  its  own  regulation,  and  elimi- 
nating the  use  of  auxiliary  apparatus. 

A  boy  sixteen  years  old  can  turn  a 
crank  fitted  on  to  the  wind-motor  axle, 
when  the  machine  is  on  the  ground,  and 
generate  sufficient  current  to  magnetize  the 
dynamo  fields  and  to  light  to  full  brilliancy 
three  16-candle-power  lights  for  a  period  of 
twenty  minutes  at  a  time. 

The  axles,  differential  gearing  and  bear- 
ings are  contained  in  a  hollow  steel  hous- 
ing, the  same  as  a  motor  car  rear  axle,  and 
this  housing  is  pumped  full  of  gear  grease. 
Several  machines  are  on  record  that  have 
not  been  re-greased  for  two  years  at  a  time. 

The  drawing  shows  that  the  automatic 
cut-out  and  cut-in  for  the  battery  is  a 
mechanical  ball  governor,  but  this  cut-out 
has  been  substituted  by  an  electro-magnetic 
cut-out  and  cut-in.  The  electro-magnetic 
cut-out  simplified  the  plant  and  is  located 
on  the  switch-board.  With  an  average 
wind  pressure  of  ten  miles  per  hour  for 
ten  hours  per  day  the  larger  plant  has  in 
practise  charged  a  25  volt  battery  with  90 
A.H.  per  days,  and  has  maintained  a  daily 
discharge  for  8  months  of  75  A.H.  per  day. 


N 


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NEW  DISTANCES  IN   RADIO  TE- 
LEGRAPHY. 

The  Marconi  station  at  Bandoeng,  East 
Indies,  has  succeeded  in  establishing  com- 
munication with  America,  Madrid  and  Ber- 
lin, according  to  The  Batavia  Nieuwsblad. 
Presumably  this  refers  only  to  the  reception 
of  messages  sent  out  from  those  parts  of 
the  world.  Experiments  are  being  made  at 
Bandoeng  with  a  view  to  the  ultimate  estab- 
lishment of  regular  wireless  communication 
with  the  mother  country,  Holland,  and  a 
300  horsepower  motor  has  enabled  the  oper- 
ators to  secure  the  promising  result  re- 
corded. 


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1S4  Warren  Street 
TOLEDO,  OHIO 


DUCK'S 

BIG  300pp.  ELECTRICAL 
and  WI RELESS  CATALOG 

Mailed  upon  receipt  of  8c  in  stamps 
or  coin  which  may  be  deducted  on 
first  dollar  purchase.  Catalog  con- 
tains 160  pages  of  wireless  instru- 
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supplies.  No  bigger  or  better  values 
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230-232  Superior  St.     Toledo,  Ohio 


"BURNELL  R.  FORD— SCIENTIST- 
ELECTRICAL  WIZARD." 

{Continued  from  page  371) 
ing  trick  of  the  electrical  conjurer  known 
as  "The  Human  Dynamo."  The  lecturer's 
assistant  lights  a  candle  from  a  stream  of 
water.  The  experiment  is  easily  performed 
by  taking  the  high-frequency  current  up 
thru  the  legs.  A  piece  of  wire  here  and 
there  often  helps  out  the  lecturer  and  pre- 
vents him  from  getting  unpleasant  shocks. 
If  the  current  is  of  sufficiently  high  fre- 
quency no  trouble  will  be  experienced  in 
passing  it  right  thru  the  body.  But— don't 
try  letting  the  current  jump  to  or  from  the 
skin  or  you  will  rapidly  lose  your  sang 
froid.  Arrange  matters  so  that  the  cur- 
rent jumps  to  or  from  a  piece  of  metal 
in  some  way.  And  your  conscience  need 
not  trouble  you,  either,  for  the  audience  is 
not  being  humbugged.  The  current  actually 
does  pass  thru  your  body,  just  the  same. 
It's  simply  a  case  of  knowing  how  to  handle 
the  current. 

The  three  lower  illustrations  are  of  Mr. 
Ford  in  a  few  more  of  his  electrical  roles. 
At  the  left  he  lights  fire  balls  by  high-fre- 
quency current  past  thru  his  body.  (The 
lecturer  stands  on  a  metal  plate  covered 
with  a  rug,  the  plate  being  connected  to 
a  high-frequency  coil.  A  metal  insole 
should  be  worn,  making  contact  with  a 
spiked  nail  in  the  heel  of  the  shoe,  which 
thus  ensures  a  good  large  area  contact  be- 
tween the  charged  plate  and  the  lecturer's 
body.)  The  center  photo  shows  the  lec- 
turer actually  lighting  up  a  bank  of  lamps 
thru  his  body.  This  experiment  always 
attract  undivided  attention  from  any  audi- 
ence, large  or  small.  It  really  is  a  re- 
markable demonstration,  involving  in  many 
cases  the  transmission  of  possibly  500,000 
volts  and  several  amperes  of  current  thru 
the  body;  and  1/10  of  an  ampere  of  low- 
frequency  alternating  current  past  thru 
the  heart  is  said  to  invariably  prove  fatal. 
In  the  final  photo  at  the  right  we  see  Mr. 
Ford  bidding  us  good-night,  and  like  all 
good  souls,  he  lights  his  candle  and  pre- 
pares to  retire.  But  he  lights  the  candle 
by  a  spark  shooting  forth  from  his  tongue. 
And  just  to  make  it  interesting  we  are  go- 
ing to  let  our  electrically  inclined  reader 
find  out  for  himself  how  this  trick  is  done. 


CHEMICAL  ACTION  OF  STORAGE 
BATTERIES. 

{Continued  from  page  401) 
explained  with  the  help  of  the  osmotic 
theory  by  Le  Blanc.  The  difficulty  in  ap- 
plying this  theory  to  the  lead  storage  bat- 
tery is  to  know  what  are  the  ions  in  the 
case  of  the  lead  peroxid  plate.  According 
to  Le  Blanc's  theory,  the  lead  peroxid, 
having  a  definite,  tho  slight  solubility,  dis- 
solves in  the  dilute  sulfuric  acid  and  then 
reacts  with  water  according  to- the  follow- 
ing equation : — 

+  + 

++  — 
(8)  Pb02  +    2H20    =    Pb      +  40H 

Lead  Water  Lead     '  Hydroxyl 

Peroxid  Radical 


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October,  1917 


THE  ELECTRICAL  EXPERIMENTER 


423 


During  the  discharge  the  tetravalent  lead 
ions  give  up  two  charges  of  electricity  and 
combine  with  the  SO<  ions  to  form  lead 
sulfate.  The  tetravalent  lead  ions  are  re- 
placed, as  they  are  used  up,  by  the  solution 
of  more  lead  peroxid.  There  is  no  loss 
in  free  energy  in  this  solution  and  reactions 
with  water,  for  both  of  these  reactions 
take  place  at  equilibrium  concentrations. 
The  spongy  lead  electrode  is  similar  to  the 
zinc  in  a  Daniell's  cell.  It  goes  in  solu- 
tion as  a  lead  ion,  but  is  precipitated  on  the 
lead  plate  because  of  the  low  solubility  of 
lead  sulfate.  The  hydrogen  ions  of  the 
sulfaturic  acid  combine  with  the  hydroxyl 
ions  of  the  equation  last  given,  to  form 
water.  The  equation  representing  the  re- 
actions that  take  place  subsequent  to  the 
reaction  of  the  last  equation  given,  for  the 
entire  battery  are  accordingly : — 

++ 
++ 

(9)      Pb       +  Pb 
Lead  Lead 


+  S04  =  2PbSO„ 
Sulfate  Lead 
Radical  Sulfate 


(10)  4  OH      +      4  H    =  4HaO 
Hydroxyl       Hydrogen  Water 
Radical 

On  the  charge  the  reverse  of  the  above 
reactions  take  place.  Both  the  positive  and 
negative  plates  are  covered  with  lead  sul- 
fate, and  the  sulfuric  acid  surrounding  the 
plates  must  also  be  saturated  with  lead 
sulfate.  On  the  negative  plate  the  lead 
ions  are  deposited  as  spongy  lead,  and  on 
the  positive  plate  the  bivalent  lead  ions  are 
oxidized  to  tetravalent  lead.  The  solution 
and  electrolysis  are  represented  by  the 
equations  : — 

++ 

(11)  2PbS04  solid      -    Pb  +  2SO* 
Lead  Sulfate  Lead  Sulfate 

Radical 

+  + 

+  +       +  + 

(12)  2Pb  =  Pb  +  Pb 

The  tetravalent  ions  then  react  with  the 


hydroxyl  ions  according  to  the  following 
equation  : — 

+  + 

++  — 

(13)  PbOa  +  2H20  =  Pb  +  4  OH 
taken  in  the  reverse  direction : — 

+  = 

(14)  2HaO  =  4  OH  +  4  H 

+  + 

+  +  — 

(15)  Pb  +  4  OH  =  PbO*  +  2H.O 

The  hydrogen  ions  corresponding  to  the 
hydroxyl  ions  and  the  sulfate  ions  from 
equation  11,  unite  to  form  sulfuric  acid: — 

+  = 

(16)  4H      +      2SO<  =  2H2SO! 
Hydrogen       Sulfate  Sulfuric 

Radical  Acid 

The  sum  of  equations  8,  9  and  10,  and 
of  the  equations  11,  to  16  will  be  found  to 
result  in  equation  7.  In  support  of  Le 
Blanc's  theory  it  may  be  stated  that 
tetravalent  lead  ions  do  exist,  and  they  are 
therefore  probably  capable  of  forming  by 
the  electrolysis  of  lead  sulfate  solutions. 

Liebenow's  theory  differs  from  Le  Blanc's 


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RADIO  TELEPHONES  FOR  LOAD 
DISPATCHING 

While  the  government  will  not  permit  the 
use  of  wireless  telegraph  and  telephone 
equipment  at  present  except  under  its  super- 
vision, the  Public  Service  Company  of 
Northern  Illinois  is  investigating  the  prac- 
ticability of  using  radio-telephones  for  load 
dispatching  so  that  some  development  can 
be  made  along  this  line  when  conditions 
will  permit.  Two  radio-telephone  sets  suit- 
able for  communication  between  sections 
150  miles  apart  have  been  purchased  and 
are  being  tested  with  the  co-operation  of 
the  United  States  Navy  Department.  If 
the  units  prove  satisfactory  on  test,  and  the 
indications  are  that  they  will,  one  unit  will 
probably  be  installed  in  the  system  oper- 
ator's office,  which  is  in  the  new  Toliet  (111.) 
generating  station,  and  the  other  will  be 
placed  in  the  company's  generating  station 
at  Blue  Island,  111.  It  will  be  possible  to 
use  the  instruments  in  these  locations  to 
facilitate  load  dispatching  in  emergencies 
that  may  be  occasioned  by  failure  of  the 
company's  private  metallic-circuit  line.  If 
the  units  prove  practicable  in  these  loca- 
tions, their  use  will  probably  be  extended  to 
other  important  switching  centers.  The 
use  of  the  radio-telephone  rather  than  the 
wireless  telegraph  was  favored  by  the  en- 
gineering department  of  the  Public  Service 
Company  of  Northern  Illinois  because  the 
instrument  can  be  used  without  a  knowl- 
edge of  the  Continental  Morse  code  and  be- 
cause it  is  possible  to  transmit  messages 
with  greater  speed  by  telephone  than  "by 
telegraph. 


CLIPPING  8,950,368,000,000  HAIRS  ON 
HORSE  IN  17  MINUTES  BY 
ELECTRICITY. 

Talking  about  horse  hairs,   about  how 


many  hairs  do  you  figure  our 
equine  friend  possesses?  Well, 
there  is  said  to  be  32,458,000  horses 
in  the  U.  S.  A.,  and  also  that  each 
horse  has  an  average  of  8,950,- 
368,000,000  hairs.  Therefore  the 
number  of  hairs  on  these  horses 
totals  up  to  290,421,544,544,000,- 
000,000. 

All  of  which  brings  us  to  the 
problem  of  clipping  these  32  mil- 
lion odd  horses.  The  electric  way 
has  proven  to  be  the  best  and 
quickest  one,  the  time  required 
for  clipping  a  full-grown  horse 
averaging  17  minutes  3l/2  seconds. 

In  the  clipping  machine  pictured, 
the  motor  is  a  vertical  type,  Y\ 
H.  P.,  equipt  with  ball  thrust  bear- 
ings. The  flexible  shafting  is  the 
hardened  steel  unit  type,  8  feet 
long,  encased  in  a  servicable  and 
neat  cover.  It  is  noiseless  and  the 
clipping  heads  are  interchange- 
able. Can  be  attached  to  electric 
light  socket.  The  advantages  of  a 
vertical  type  motor  over  the  old 
portable  motor  are  manifold — 
viz. :  Out  of  the  way  of  the  op- 
erator. No  moving  of  motor. 
Greater  compass  in  working. 
Takes  up  considerably  less  space, 
and  when  thru  can  be  hung  up 
out  of  the  way.  Of  course  the 
machine  can  clip  other  hair  be- 
sides horse  hair.  Our  illustration 
shows  what  the  Wall  street  broker 
would  term  "shearing  the  lamb." 


Shearing  a  Lamb 
with  an  Electric 
Clipper.  It  Will 
Clip  a  Horse  in  17 
Minutes,  3[/2 
Seconds. 


424 


THE  ELECTRICAL  EXPERIMENTER 


October,  1917 


War  Conditions  Demand 
ELECTRICAL 


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only  as  to  the  action  of  the  peroxid  elec- 
trode. According  to  this  theory  the  lead 
peroxid  goes  into  solution  as  doubly 
charged  lead  peroxid  ions,  so  that  the 
peroxid  plate  is  to  be  considered  a  re- 
versible electrode  with  respect  to  the  per- 
oxid ions.  On  discharge,  the  peroxid 
passes  into  the  solution  surrounding  the 
peroxid  plate,  which  is  already  saturated 
with  respect  to  these  ions.  They  then  re- 
act with  the  hydrogen  ions  of  the  acid  as 
follows : 

+  ++ 

(17)  PbOo  +  4  H  =  Fb  +  2H20 

The  lead  ions  then  combine  with  the  sul- 
fate ions  to  form  solid  lead  sulfate : — 

+  + 

(18)  Pb  +   S04  =   PbS04  solid 

During  charge,  just  the  reverse  reactions 
take  place.  The  lead  peroxide  ions  are  de- 
posited on  the  positive  plate,  and  are  re- 
placed as  they  are  used  up  by  the  solution 
of  the  sulfate  from  the  electrode  and  its 
hydrolysis : 

++  + 

(19)  Pb  +  2H20  =  Pb02  +  4H 

The  work  obtainable  from  a  storage  bat- 
tery depends  on  its  capacity  and  the  electro- 
motive-force measured  at  its  poles  while  the 
current  is  flowing.  If  V  is  the  voltage  on 
charging,  E  is  the  open  circuit  electromotive 
force,  I  is  the  charging  current,  and  R  is 
the  resistance  of  the  battery,  then 

(20)  V    =  E  -f-  IR  and  on  discharge, 

(21)  V1  =  E  +  IR 

(To  be  concluded) 


EXPERIMENTAL  PHYSICS. 

(Continued  from  page  386) 
perpendicular  to  the  mirror  and  E3C  pro- 
longed ;  the  image  of  B  will  be  found  on  the 
straight  line  E^B,  prolonged  perpendicular 
to  the  mirror  and  along  the  line  E3D. 
These  lines  may  be  marked  on  the  paper 
after  sighting  along  a  ruler  or  other 
straight-edge.  If  now  these  lines  are  pro- 
longed after  removing  the  mirror,  the  in- 
tersection of  AF  and  E3C  will  be  the  point 
A1  the  image  of  A.  and  the  intersection  of 
BC  and  E3D  the  point  B1  the  image  of  B. 
Light  from  A  going  along  the  direction  AF 
is  reflected  back  and  appears  to  come  from 
A1.  Light  from  A  going  in  the  direction 
AC  is  reflected  along  CE3  making  the  angle 
of  incidence  equal  to  the  angle  of  reflection. 

In  a  similar  manner  light  from  B  appears 
to  come  from  B1  and  light  from  each  of  the 
points  in  between  A  and  B  appears  to  come 
from  definite  points  in  between  A1  and  Bl 
thus  forming  the  complete  image  of  AB. 
If  the  distances  AF  and  A'F  are  measured, 
they  will  be  found  equal.  The  same  holds 
true  for  BC  and  B'C  and  for  any  other  set 
of  corresponding  points.  In  short,  we  have 
learned  that  EACH  POINT  OF  AN 
IMAGE  IN  A  PLANE  MIRROR  IS  AS 
FAR  BEHIND  THE  MIRROR  AS  THE 
CORRESPONDING  POINT  OF  THE 
OBJECT  IS  IN  FRONT  OF  THE 
MIRROR. 

The  question  is  often  asked,  "If  a  person 
runs  toward  a  mirror,  how  fast  does  he  ap- 
proach his  image?"  The  answer  of  course 
is;  he  approaches  twice  as  fast  as  he  is  run- 
ning. The  image  is  just  as  far  behind  as 
the  person  is  in  front  and  hence  if  the  per- 
son approaches  a  certain  distance,  the  image 
approaches  an  equal  distance,  or  the  image 
and  person  are  nearer  by  twice  the  distance 
that  the  person  approached.  It  can  be  shown 
that  a  mirror  must  be  at  least  half  as  tall  as 
a  person  in  order  that  the  person  may  see 
his  whole  image.  This  is  left  as  an  ex- 
ercise to  the  reader  to  try,  and  the  author 
will  gladly  look  over  any  solutions  that  may 
be  sent  to  him. 

EXPERIMENT  48.  A  very  simple  ex- 
periment can  be  performed  which  will  il- 
lustrate the  manner  in  which  many  of  the 


magician's  tricks  are  performed.  Let  M 
represent  an  ordinary  milk  bottle  filled  with 
water,  GG  a  piece  of  smooth  polished  glass 
(the  window  after  the  pane  has  been  well 
cleaned  will  do),  C  is  a  candle,  and  AB  a 
board  or  other  opaque  object  to  screen  the 
lighted  candle.  When  the  eye  is  at  E,  the 
observer  cannot  see  the  candle  C,  because  it 
is  screened  by  AB.  Light  from  the  candle 
however  on  striking  the  points  P  to  Q  is 
reflected  according  to  our  previously  dis- 
cust  law,  and  appears  to  come  from  inside 
the  bottle.  Hence  we  see  the  image  of  the 
candle  in  the  bottle,  and  not  seeing  the 
candle  itself  we  are  mystified  to  find  that 
a  candle  may  burn  in  -water.  Obviously,  with 
large  pieces  of  plate  glass  and  by  use  of 
trap  doors  and  strong  light  a  person  under 
the  stage  may  be  made  to  appear  on  the 
stage.  When  the  magician  shoots  his  gun 
at  the  image  or  ghost  it  disappears  (lights 
were  turned  off  underneath  the  stage). 
Also  men  may  walk  thru  other  men,  men 
and  women  may  change  places  in  cages, 
heads  without  the  rest  of  the  human  body 
may  be  made  to  -appear,  etc.,  etc. 

EXPERIMENT  49.  A  piece  of  apparatus 
can  be  easily  made  as  in  Fig.  39-A,  the 
working  of  which  depends  solely  on  the  law 
of  reflection,  but  which  seems  complicated 
to  the  person  ignorant  of  Physics.  M  and 
M1  are  small  mirrors  or  pieces  of  mirror 
placed  at  angles  of  45  degrees  in  their  re- 
spective corners.  Mirrors  M1  should  each 
have  a  hole  bored  thru  them  or  else  be  cut 
and  have  openings  near  their  centers.  If 
now  an  object  is  placed  at  B  and  the  hand 
or  a  brick  or  other  screen  at  A,  the  object 
will  be  seen  by  the  eye  at  E,  since  light  from 
the  object  B  is  reflected  by  mirror  M1  to 
Mi  and  from  Mi  to  M>  and  thence  from  M2 
to  M1  and  from  M1  to  the  eye.  If  now  the 
screen  be  removed  from  A  and  an  opaque 
object  placed  in  the  tube  at  S,  the  light  from 
B  will  pass  thru  the  holes  in  the  M1  mirrors 
and  to  the  eye  at  E  so  that  the  object  will 
be  seen  in  either  case.  Care  must  be  taken 
not  to  have  screens  in  place  at  A  and  S  at 
the  same  time  for  then  there  is  no  path 
thru  which  the  light  may  pass  from  B  to  E. 

This  same  principle  of  reflection  is  made 
use  of  in  the  modern  submarine  boat.  A 
long  tube  AB  (see  Fig.  39-B)  with  joints 
CA  and  BD  extending  in  opposite  directions. 
Small  mirrors  are  placed  at  A  and  B,  mak- 
ing angles  of  45  degrees.  Light  from  a 
distant  ship  is  reflected  by  mirror  A  to 
mirror  B  and  the  image  is  seen. 

EXPERIMENT  50.  When  light  passes 
from  air  to  water  or  some  other  liquid  it 
is  bent.  This  phenomenon  is  called  re- 
fraction. This  refraction  can  be  shown  to 
be  due  to  the  retarding  of  the  speed  of  light 
when  passing  thru  a  medium  more  dense 
than  air.  If  a  spoon  or  a  pencil  is  placed 
in  a  tumbler  partly  filled  with  water  (see 
Fig.  40-A),  it  will  appear  bent.  Place  a  coin 
in  a  bowl  and  step  back  from  it  until  you 
just  miss  seeing  the  coin.  If  water  is  poured 
into  the  bowl  carefully  by  someone  without 
disturbing  the  coin  and  you  stay  in  your 
original  position  you  will  find  that  you  sud- 
denly see  the  coin.  The  explanation  is  re- 
fraction. While  the  coin  is  at  A  before  the 
water  is  in  the  bowl,  the  observer  will  see  it 
if  his  eye  is  along  the  line  ABD  and  hence 
if  the  eye  is  at  E  the  coin  will  not  be  seen. 
However  when  water  is  poured  into  the 
bowl,  light  from  A  is  bent  along  the  broken 
line  ABE  and  the  coin  is  seen  and  appears 
to  be  at  C,  since  the  eye  is  accustomed  to 
consider  light  to  reach  it  thru  a  straight 
line  path. 

At  this  point  it  may  be  well  to  consider 
briefly  what  the  present  theory  of  light  is, 
or  rather  to  give  the  reader  a  start  so  that 
he  may  later  read  up  intelligently  on  the 
subject.  Like  sound,  light  is  considered  to 
be  a  wave  motion.  The  theory  was  first 
formulated  by  Huygens,  the  great  Dutch 


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THE  ELECTRICAL  EXPERIMENTER 


425 


Physicist,  in  1629-1695.  The  theory  met 
with  opposition  on  two  grounds  and  even 
the  great  Newton  died  without  accepting  the 
theory  which  is  universally  accepted  today. 
First,  light  travels  thru  vacua,  and  the  better 
the  vacuum  the  greater  the  speed,  whereas 
sound  does  not  travel  thru  vacua  at  all. 
Hence,  if  light  is  really  a  wave  motion  it  is 
thought  to  be  a  motion  of  some  medium 
which  fills  all  space,  but  does  not  retard  th< 
motion  of  the  stars  and  planets.  [Good 
serials  stop  at  tense  moments  like  this,  so 
we  will  stop  here  and  say  "continued  in  our 
next  issue."] 


MAKING  AN  ELECTRIC  CLOCK. 

(Continued  from  page  396) 
W  hen  you  have  your  arbors  all  done 
and  wheels  mounted,  the  hardest  job  is 
locating  the  bearing-holes  in  your  plates, 
so  that  your  gears  will  run  neither  too 
tight  nor  too  loose.  I  made  an  adjustable 
frame  (Fig.  9),  in  which  the  wheels  could 
be  set;  and  when  they  were  running  just 
right,  I  scratched  the  distance  on  the  plates 
with  the  sharpened  ends  of  the  arbors. 
Screw  the  two  plates  flat  together,  and  drill 
them  both  at  the  same  time.  These  holes 
have  to  be  center-punched  and  drilled  with 
all  the  care  you've  got  in  your  system,  as 
a  wonderfully  small  error  will  make  your 
gears  work  as  hard  as  getting  Johnny  home 
at  supper-time. 

That's  all.  Look  like  a  good  deal  of 
work?  Well,  perhaps  it  is.  It's  a  great 
pity  you  can't  buy  these  wheel-works  ready 
made.  A  movement  like  Fig.  6  (just  the 
plates  and  wheels,  I  mean,  without  the  es- 
capement) would  be  very  simple  and  cheap 
for  a  clock-manufacturer  to  produce.  May- 
be, if  there  was  enough  call  for  'em,  the 
supply  houses  advertising  in  the  "E.  E." 
would  have  some  made  up.  Why  don't 
you  send  the  "Ed."  a  postal  saying  you  are 
interested?  and  if  enough  postals  came  in, 
perhaps  the  Co.'s  will  get  excited  and  think 
they  see  some  business.  The  wheel-work 
is  mainly  a  nuisance ;  and  with  that  off 
his  mind,  a  long-suffering  "Bug"  would  be 


free  to  put  his  main  effort  into  the  pendu- 
lum and  other  mechanisms.  There  are 
several  principles,  such  as  torsion  and  scale- 
spring  oscillation,  working  more  or  less 
in  time-keeping  intervals,  that  you  want 
to  try,  but  you  don't  feel  like  going  to 
the  trouble  of  making  up  wheel-work  for 
each  one. 

I  want  to  say  right  here,  that  in  this 
clock  game  it's  "no  fairs"  designing  a 
mechanism  to  run  on  an  electric-light  cur- 
rent. The  first  rule  is,  it  must  run  on 
one  dry-cell,  and  the  end  to  aim  at  is  hav- 
ing the  cell  dry  up  on  you  before  the 
clock  takes  all  its  electrical  output.  You'll 
find  that's  hitching  your  wagon  to  a  star- 
wheel. 

Oh,  just  to  round  out  the  article — as 
to  clock  hands — you  can  make  them,  of 
course,  but  they're  very  cheap  and  it  doesn't 
pay  to  try.  The  dial  you  can  make  all 
right.  Make  it  of  zinc — wood  is  too  apt 
to  warp  and  stop  your  hands.  Wrinkle : 
Put  a  coat  of  shellac  on  your  zinc  before 
you  paint  it,  otherwise  your  paint  will  peel 
off  when  very  dry.  Lay  out  your  figures 
and  circles  on  paper  first,  and  transfer  them 
to  the  painted  surface  with  carbon  paper. 
If,  like  me,  you  haven't  an  artistic  hand, 
you  can  put  in  the  figures  with  India  ink 
and  a  ruling  pen.  You  can  buy  excellent 
engraved  paper  dials  up  to  11  inches  di- 
ameter, but  unfortunately  that  isn't  quite 
big  enough  for  a  really  swell  looking  tall 
clock. 

Fig.  10  is  a  detail  sketch  of  a  tall  clock 
case.  The  design  is  copied  from  a  very 
old  clock,  and  is  simple  and  pleasing  and 
easy  to  make.  Use  Y\"  stock.  For  the  arch 
over  the  dial,  select  a  nice  colored  picture 
and  stick  it  on  with  shellac. 

Final  wrinkle :  Harden  up  your  heart 
like — like  agate  against  all  married  sis- 
ters, aunts,  friends  of  the  family,  and  such 
like  fry,  for  if  you  begin  producing  clocks, 
they'll  beg  'em  from  you  faster  than  you 
can  make  'em.  You  don't  have  any  dif- 
ficulty in  extorting  admiration  as  in  the 
case  of  your  more  mysterious  rinktums ; 
they  go  into  fits  over  'em,  and  contemplate 
larceny  on  you. 

(Continued  on  page  427) 


Radio  "De  Luxe"  Crystal  Set" 

For  Commercial,  Navy  and  Army  Operators 


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It  is:  "The  right  thing  in  the  right  place,  and  the 
right  place  for  the  right  thing." 

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The  box  can  be  carried  easily  in  the  pocket  on  account 
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It  contains: 

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One  piece  of  tested  Galena. 

One  piece  of  tested  Silicon. 
Furthermore,  one  18  Karat  Gold  Catwhlsker  and  two 
phosphor  bronze  catwhlskers  of  different  shapes. 

It  is  not  necessary  for  us  to  indulge  here  upon  the 
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use  today  in  all  well  equipped  Radio  Stations:  we 
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Our  Silicon  is  fused  material,  imported  by  us  from 
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426 


THE  ELECTRICAL  EXPERIMENTER 


October,  1917 


iEXPERIM  ENTERS! 


The  "Electro"  Codophone 

(Patents  Pending) 

Now  that  we  are  for  the  time  being,  deprived  of  using  our 
Radio  outfits,  it  behooves  us  as  good  Americans  to  become 
proficient  in  learning  the  Wireless  as  well  as  Telegraph 
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way  near  all  the  operators  it  requires.  Not  alone  does  the 
Federal  Government  call  for  thousands  and  thousands  of 
operators  for  the  army  and  navy,  but  nearly  all  of  our  many 
states  require  operators  for  the 
militia.  Here  is  the  great  opportun- 
ity of  a  life  time  for  you. 

Would  you  rather  fight  in  the 
trenches,  or  punch  the  key  behind 
the  lines?  Either  way  you  benefit 
your  country.  Which  do  you  prefer? 
And  it  is  SO  easy  to  become  an  oper- 
ator. You  do  not  necessarily  require 
a  teacher,  nor  do  you  have  to  go  to 
a  school  to  learn.  30  days  of  intel- 
ligent study  will  make  you  proficient. 
Can  you  qualify  NOW?  Are  you 
proficient?  Can  you  send  and  receive 
when  your  country  calls  you?  . 

THE  "ELECTRO"  CODOPHONE 

(Patents  Pending) 
which  we  present  herewith  is  the 
outcome  of  several  months  of  intense 
study  and  experimentation  of  our 
Mr.  H.  Gernsback.  It  supersedes  our 
former  Radiotone  Codegraph,  which 
comprised  a  Radiotone  silent  Buzzer, 
a  loud  talking  telephone  receiver  and 
a  key.  As  in  all  of  his  work  Mr.  Gernsback  strives  for  simplicity.  So 
he  combined  the  three  above  mentioned  instruments  with  one  stroke  into 
ONE  single  instrument.  He  combined  the  Radiotone  Buzzer  and  the  loud 
talking  receiver  into  a  single  unit,  not  only  mechanically,  but  electrically 
as  well.  This  involves  an  entirely  new  principle,  never  before  attempted, 
and  on  which  basic  patents  are  now  pending. 

What  this  remarkable  instrument  is  and  does. 
The  "Electro"  Codophone  is  positively  the  only  instrument  made  that 
will  imitate  a  500  cycle  note  exactly  as  heard  in  a  Wireless  receiver,  so 


closely  and  so  wonderfully  clear,  that  Radio  operators  gasp  in  astonish- 
ment when  they  first  hear  it.  And  you  need  no  receivers  over  the  ears  to 
hear  the  imitation  singing  spark,  which  sounds  for  all  the  world  like  a 
high-pitched  distant  powerful  Radio  Station.  No,  the  loud-talking  receiver 
equipped  with  a  horn,  talks  so  loud  that  you  can  hear  the  sound  all  over 
the  room,  even  if  there  is  a  lot  of  other  noise. 

THAT'S  NOT  ALL.  By  lessening  or  tightening  the  receiver  cap,  a  tone 
from  the  lowest,  softest  quality,  up  to  the  loudest  and  highest  screaming 
sound  can  be  had  in  a  few  seconds. 

FURTHERMORE,  this  jack-of-all-trades  marvel,  can  be  changed  in- 
stantly into  our  famous  silent  Radiotone  test  buzzer,  simply  by  replacing 
the  metal  diaphragm  with  a  felt  disc,  which  we  furnish  with  every  instru- 
ment. 

FOR  INTERCOMMUNICATION.  Using  two  dry  cells  for  each  instru- 
ment, two  Codophones  when  connected  with  one  wire  and  return  ground, 
can  be  used  for  intercommunication  between  two  houses  one-half  mile 
apart.  Any  one  station  can  call  the  other,  no  switches,  no  other  appliances 
required.    No  call  bell  either,  the  loud-talking  phone  takes  care  of  this. 

AS  AN  ARMY  TYPE  BUZZER.  Last,  but  not  least,  two  Codophones 
with  two  75  ohm  receivers  can  be  used  to  converse  over  miles  of  fine  (No. 

36  B  &  S  Wire),  so  fine  that  no  one 
can  see  the  wire.  Or  you  can  use  a 
long  metallic  fence  and  the  ground, 
or  you  can  communicate  over  your 
110  volt  line  up  to  several  miles,  us- 
ing no  wires,  only  the  ground. 

Full  directions  how  to  do  all  this 
furnished  with  each  instrument. 

One  outfit  alone  replaces  the  old- 
fashioned  learner's  telegraph  set, 
consisting  of  key  and  sounder,  which 
is  all  right  to  learn  the  telegraph 
code  but  not  the  wireless  codes. 

The  "Electro"  Codophone  is  a 
handsome,  well  made  instrument, 
fool  proof,  and  built  for  hard  work. 
Contacts  are  of  hard  silver  %  inch 
in  diameter,  that  will  outlast  the  in- 
strument. Base  and  housing  is  of 
metal'  throughout,  horn  and  key 
lever  nickel  plated  and  buffed.  Three 
new  style  metal  binding  posts  are 
furnished. 

There  is  also  a  neat  code  chart  and 
full  directions  enabling  any  intelli- 
gent young  man  or  girl  to  learn  the  codes  within  30  days,  practising  one- 
half  hour  a  day. 

Sizes:  6%   x  3  x  2%".     Shipping  weight,  4  lbs. 
The  "Electro"  Codophone  as  described,  complete 

Money  refunded  if  instrument  is  not  as  represented  or  does  not  come  up 
fully  to  expectation. 

Ready  for  delivery  Aug.  25th.  There  will  be  an  enormous  demand  for 
this  new  marvel — place  your  order  now.  All  orders  filled  in  rotation. 
Better  order  two  instruments  today. 


$1.35 


THE   "ELECTRO"  SPINTHARISCOPE 

As  usual  we  lead — others  follow.  Now  the  Spinthari- 
scope, first  to  be  introduced  to  the  American  public  by 
us.  The  Spinthariscope  was  originated  by  the  famous 
English  Radium  expert,  Sir  William  Crookes.  Everyone 
kn6vvs  that  Radium  gives  off  a  tremendous  amount  of 
energy  which  goes  on  for  several  thousand  years,  with 
undiminished  force. 


MAKING  RADIUM 
VISIBLE 


Radium  gives  off  a  number  of  rays  of  which  the 
Alpha  rays  are  known  chiefly  for  their  great  power. 

These  electric  rays  are  invisible  to  the  naked  eye,  the 
same  as  are  X-rays.  But  if  we  take  a  small  amount  of 
Radium  and  place  it  in  front  of  a  zinc-sulfide  screen, 
the  latter  lights  up.  If  the  radium  speck  is  arranged 
suitably  the  Alpha  rays  will  bombard  the  zinc  sulfide 
with  a  veritable  hail  of  electrons  and  the  screen  begins 
to  scintillate  like  Fourth  of  July  fireworks. 

This  is  the  principle  of  the  Spinthariscope,  which  we  present  herewith. 
It  is  a  little  instrument  made  of  two  neatly  nickeled  metal  tubes,  one 

You  owe  it  to  yourself  to  own  one.  It  is  small  enough  to  be  put  into 
It  will  continue  to  operate  after  you  are  dead  2500  years!  We  guarante 
Radium  salts.    "Electro"  Spinthariscope,  in  neat  box  and  directions  for  u 

Sent   Prepaid.  IMME 


telescoping  into  the  other.  The  top  tube  has  a  powerful 
lens.  The  bottom  contains  the  zinc-sulfide  screen  and 
a  minute  quantity  of  REAL  RADIUM,  too  small  to  do 
any  harm.  The  instrument  can  only  be  used  in  the 
dark.  After  the  top  tube  with  the  lens  has  been  ad- 
justed to  the  right  focus,  we  observe  a  vividly  illumi- 
nated green  background,  glowing  in  a  soft  light.  As 
the  eve  becomes  accustomed  to  it,  we  begin  to  see  the 
ELECTRONIC  BOMBARDMENT  of  the  Alpha  rays  from 
the  Radium,  It  looks  exactly  like  tiny  fireflies  flashing 
off  and  on  in  the  dark  night.  The  more  we  look  the 
better  we  see  the  miniature  fireworks.  We  are  now  in 
the  presence  of  the'  most  marvelous  substance  man  ever 
knew,  RADIUM  and  its  uncanny  forces — Radium,  which 
some  day  will  turn  the  world  upside  down. 

The  Spinthariscope  up  to  now  sold  from  $10.00  up- 
wards, but  by  greatly  simplifying  it  the  cost  has  been  brought  down  by 
us  to  such  a  nominal  figure,  that  no  one  can  afford  to  be  without  this 
most  important  and  marvelous  instrument.  * 
your  vest-pocket,  and  interesting  enough  to  show  it  to  all  of  your  friends, 
the  instrument  to  be  genuine  and  to  contain  a  minute  quantity  of  real 

se,  as  described  tfl  f\(\ 

DIATE    SHIPMENTS.  «pJ..VV 


LABORATORY  OUTFIT! 


We  have  spent  considerable  time  to  com- 
bine just  such  a  practical  outfit  and  pre- 
sent it  herewith  to  our  friends. 

The  outfit  is  complete  as  per  Illustration 
and  consists  of : 

1  Stand,  made  of  well  quartered  oak. 
varnished  three  times,  so  as  to  be  acid  proof 
and  grooved  on  top  and  bottom,  so  that  it 
will  not  warp  in  getting  wet.  Size  5% 
inches  high  by  11  Vz  inches  long. 

1  Glass  Spirit  Lamp.  Size  3%  inches  by 
2  inches.  Uses  wood  alcohol  and  is  in- 
valuable to  the  experimenter.  Besides  be- 
ing used  to  heat  test-tubes  contents  as  per 
illustration,  it  can  be  used  to  bend  glass 
rods  and  tubings,  to  solder  wire,  etc. 

1  Glass  Filter  Funnel.  This  funnel  is 
made  of  heavy  glass  that  will  not  break 
easily.  It  fits  accurately  in  the  hole  on  top 
of  the  Filter  stand  and  is  provided  with  a 
thick  rim  on  the  outlet,  so  that  a  rubber 
hose  can  be  attached  to  it,  without  slipping 
off. 

1  Glass  Rod,  to  be  used  in  stirring  and 
mixing. 

10  Test  Tubes,  made  from  the  best  im- 
ported glass.  A  new  feature  of  some  of 
the  test  tubes  is  that  they  have  a  flat  bot- 
tom and  therefore  can  be  placed  on  any 
table  if  desired,  needing  no  special  stand. 

1  Roll  of  Copper  Clad  Steel  Wire.  This 
wire  is  to  be  used  to  make  a  number  of  use- 
ful articles  as   shown  in   the  illustration. 


such  as  test-tube  holders,  tripods  to  support 
retorts,  etc.  We  furnish  a  blue  print  with 
the  outfit,  showing  how  to  make  all  these 
wire  articles. 

Now  this   whole  outfit   as   described  CI 
costs  you  only   

Postage  extra.    Shipping  weight,  4  lbs. 
Order  one  today,  even  if  you  don't  need 
it  now. 

"The  Livesi  Catalog  in  America" 

Our  big,  new  electrical  cyclopedia  No.  IS 
is  waiting  for  you.  Positively  the  most  com- 
plete Wireless  and  electrical  catalog  in  print 
today.  200  Big  Pages.  BOO  illustrations.  500 
instruments  and  apparatus,  etc.  Big  "Trea- 
tise on  Wireless  Telegraphy."  20  FREE 
coupons  for  our  160-page  FREE  Wireless 
Course  in  20  lessons.  FREE  Cyclo- 
pedia  No.  18  -  measures  7x5%".  I 
Weight  %  lb.    Beautiful  stiff  covers.  I 

Now  before  you  turn  this  page  write  Q| 
your  name  and  address  on  margin,  be- 
low, cut  or  tear,  out,  enclose  6  cts. 
stamps  to  cover  mail  charges,  and  the 
Cyclopedia  is  yours  by  return  mail. 

THE  ELECTRO  IMPORTING  CO. 
231  Fulton  Street,  New  York  City 


ELECTRO  IMPORTING  CO.,  231  Fulton  St.,  N.  Y. 


mil1 


You  benefit  by  mentioning  "The  Electrical  Experimenter"  when  writing  to  advertisers. 


October,  1917 


THE  ELECTRICAL  EXPERIMENTER 


42  7 


MAKING    AN  ELECTRIC 
CLOCK. 

(Continued  from  page  425) 

By  this  time,  you're  either  got  the  craze, 
or  are  deathly  sick  of  clocks..  If  the  form- 
er, I  could  give  you  a  little  spiel  on  un- 
usual forms  of  movement,  striking-mech- 
anisms, and  other  daffy  dope,  but  I  got  to 
be  coaxed — that  is,  you  mail  the  Editor  a 
nut  or  something  to  show  you're  crazy  and 
not  bored,  because  I  don't  want  him  to 
load  up  his  Mag,  with  the  kind  of  stuff 
that  you  skip  when  you  come  to  it.  I'm 
a  modest  and  retiring  guy — what's  that? — 
Yes  I  am,  too,  and  I  can  prove  it  in  court 
if  I  have  to.    Now,  is  everybody  happy? 


Dimensions  of  Cabinet  for  Home-Made  Elec- 
tric Clock  As  Here  Described.    A  Graceful, 
Yet  Simple  Design. 


TRIALS  OF  A  TROUBLE- 
SHOOTER. 

(Continued  from  page  399) 

by  the  tiny  black  spots  on  the  rod  where 
the  lacquer  had  been  burnt. 

Yes  indeed,  trouble  shooting  is  "Sport," 
sometimes. 

There  are  possibly  more  chances  for 
ridiculous  situations  and  strange  mistakes 
in  the  installing  end  of  the  game.  Trouble 
is  oftimes  encountered  in  properly  ground- 
ing the  'phone.  One  subscriber  has  to 
water  his  ground  rod  every  day  or  so  to 
keep  the  'phone  working  properly.  Re- 
minds me  of  the  chap  that  wanted  to 
ground  on  a  coal  bucket.  He  even  offered 
to  allow  enough  slack  so  the  lady,  of  the 
house  could  bring  coal  out  of  the  cellar. 

And  streaks  of  luck,  let  me  tell  you 
about  a  certain  incident  that  caps  them  all. 
On  a  certain  job  it  was  necessary  to  drill 
a  hole  thru  the  floor  to  pass  a  pair  of 
wires.  Going  down  the  cellar  he  started 
to  drill  up.  After  sinking  the  drill  some 
six  inches  he  began  to  wonder  how  thick 
the  blamed  floor  was.    He  went  upstairs 


and  lookt  for  the  hole  but  none  was  in 
evidence. 

He  then  returned  to  the  brace  and  sunk 
it  another  three  inches  before  he  decided 
to  check  up  his  measurements.  After  a 
little  trouble  he  located  the  place  where 
the  hole  was  coming  thru.  Where,  you 
ask? 

Up  a  Piano  Leg ! 

And  plumb  in  the  center.  A  quarter 
inch  either  way  would  have  broken  thru 
the  veneer. 


EXPERIMENTAL  CHEMISTRY. 

(Continued  from  page  405) 
Manufacture  : 

On  a  large  scale  it  is  made  mostly  from 
the  ammoniacal  liquor  of  the  hydraulic 
main  of  gas  houses,  which  results  from  the 
destructive  distillation  of  soft  coal.  This 
liquor  contains  dissolved  (NHO2S;  (NH(): 
CO3 ;  etc.,  and  when  treated  with  hydro- 
chloric acid,  nitric  acid  or  sulfuric  acid,  it 
gives  the  salts  NH4CI,  etc.,  and  from  these 
salts  "liquor  ammonia"  is  obtained.  Great 
quantities  of  the  gas  are  formed  in  the  pre- 
paration of  coke  in  the  iron  regions. 

Properties  : 

Physical:  1.  Ammonia  (NHs)  is  a  color- 
less gas,  possessing  a  pungent  and  char- 
acterisitc  odor  and  acrid  taste. 

2.  It  is  very  easily  soluble  in  water,  with 
which  it  combines  to  form  the  hydroxid, 
which  in  turn  gives  off  the  gas  at  all  tem- 
peratures. 

3.  Ammonia  can  be  liquefied  and  when  in 
that  state  it  is  colorless.  The  liquid  boils 
at  -40  deg. 

4.  It  solidifies  at  about  -80  deg. 

5.  Its  own  evaporation  may  produce  cold 
enough  to  freeze  water,  hence  the  making 
of  artificial  ice. 

6.  Charcoal  rapidly  absorbes  ammonia 
which  may  be  shown  by  introducing  a  piece 
of  charcoal  into  a  tube  of  the  gas  over 
mercury. 

Chemical  : 

1.  It  is  not  ordinarily  a  combustible  gas 
or  supporter,  but  if  mixed  with  a  small 
quantity  of  oxygen  combustion  readily 
takes  place  on  the  application  of  a  flame, 
with  the  formation  of  water,  nitrogen,  and 
nitric  acid. 

2.  Like  other  bases,  it  combines  with  acids 
forming  salts. 

3.  It  gives  a  strong  alkaline  reaction. 

4.  NHs  partially  dissociates  into  its  ele- 
ments at  500  deg.,  as  may  be  shown  by 
passing  it  thru  a  red-hot  tube. 

5.  The  two  elements  do  not  combine 
under  ordinary  conditions. 

6.  It  is  decomposed  at  red  heat  or  by 
the  electric  spark  into  nitrogen  and  hydro- 
gen; when  past  over  heated  sodium,  potas- 
sium, or  magnesium,  the  nitrogen  combines 
with  the  metal,  forming  a  nitrid,  and  hydro- 
gen escapes  : 

3Mg  +  2  NHs  =  Mg3  N2  +  3  H2 
When  treated  with  an  excess  of  chlorin 
or  iodin,  a  salt  of  ammonia  results,  which 
in  turn  is  decomposed  by  the  halogen,  yield- 
ing very  explosive  compounds,  as  nitrogen 
chlorid  (NCL)  or  nitrogen  iodid  (NHL 
or  NL). 

Detection  : 

(1)  Ammonia  and  its  solution  (the  hy- 
droxid) are  very  easily  detected  by  the 
characteristic  odor.  (2)  In  smaller  quan- 
tities by  bringing  over  the  suspected  solu- 
tion a  piece  of  moistened  red  litmus  paper, 
which  it  turns  blue.  (3)  A  still  more 
delicate  test  is  the  reaction  with  fumes  of 
hydrochloric  acid.  A  rod  or  piece  of  paper 
moistened  with  the  diluted  acid  is  brought 
(Continvrd  on  paqe  429) 


TYPEWRITER  SENSATION 

FREE  TRIAL  Use  as  You  Pay.  Only 
$2.50  a  month  until  the  low  total  price  of 
$48.80  is  paid  and  the  machine  is  yours. 


FREE 
TRIAL 


This  is  absolutely  the  most  generous 
typewriter  offer  ever  made.  Do  not  rent  a 
machine  when  you  can  pay  $2.50  a  month 
and  own  one.  Think  of  it — Buying  a 
$100.00  machine  for  $48.80.  Cash  price, 
$45.45.  Never  before  has  anything  like 
this  been  attempted. 

Visible     L  •   C  •  S  HI  1 1  ll 

Perfect  machines,  Standard  size, 
Keyboard  of  Standard  Universal  arrange- 
ment writing  84  characters — universally  used  in 
teaching  the  touch  system.  The  entire  line  of 
writing  completely  visible  at  all  times,  has  the 
tabulator,  the  two  color  ribbon,  with  automatic 
reverse,  the  back  spacer,  ball  bearing  type  bars, 
bail  bearing  carriage  action,  ball  bearing  shirt 
action,  in  fact  every  late  style  feature  and  modem 
operating  convenience.  Comes  to  you  with  every- 
thing complete;  tools,  cover,  operating  book  and 
Instructions,  ribbon,  practice  paper — nothing  ex- 
tra to  buy.  Tou  cannot  Imagine  the  perfection  of 
this  beautiful  reconstructed  typewriter  until  you 
have  seen  it.  I  have  sold  several  thousand  of 
these  perfect  latest  style  Model  No.  2  machines 
at  this  bargain  price  and  every  one  of  these 
thousands  of  satisfied  customers  had  this  beau- 
tiful, strictly  up  to  date  machine  on  Ave  days' 
free  trial  before  deciding  to  buy  it.  I  will  send 
It  to  you  F.  O.  B.  Chicago  for  five  days'  free 
trial.  It  will  sell  itself,  but  if  you  are  not  sat- 
isfied that  this  is  the  greatest  typewriter  you  ever 
saw,  you  can  return  it  at  my  expense.  You 
won't  want  to  return  It  after  you  try  It — you 
cannot  equal  this  wonderful  value  anywhere. 

You  Take  No  Risk— Put  in  Your  Order  Now 

When  the  typewriter  arrives  deposit  with  the  ex- 
press agent  $8.80  and  take  the  machine  for  five 
days'  trial.  If  you  are  convinced  that  it  is  the 
best  typewriter  you  ever  saw,  keep  it  and  send 
me  $2.50  a  month  until  our  bargain  price  of 
$48.80  is  paid.  If  you  don't  want  it,  return  it 
to  the  express  agent,  receive  your  $8.80  and  re- 
turn the  machine  to  me.  I  will  pay  the  return 
express  charges.  This  machine  is  guaranteed  just 
as  if  you  paid  $100.00  for  It.  It  is  standard. 
Over  one  hundred  thousand  people  own  and  use 
these  typewriters  and  think  them  the  best  ever 
manufactured.  The  supply  at  this  price  Is  very 
limited,  the  price  will  probably  be  raited  when 
my  next  advertisement  appears,  so  don't  delay. 
Fill  In  the  coupon  today — mall  to  me— the  type- 
writer will  be  shipped  promptly.  There  Is  no 
red  tape.  I  employ  no  solicitors — no  collectors — 
no  chattel  mortgage.  It  is  simply  understood  that 
I  retain  title  to  the  machine  until  the  full  $48.80 
is  paid.  Tou  cannot  lose.  It  is  the  greatest  type- 
writer opportunity  you  will  ever  have.  Do  not 
send  me  one  cent.  Get  the  coupon  In  the  malls 
today — sure. 

Harry  A.  Smith,  738,  231  N.  Fifth  A  v..  Chicago 


H.  A.  Smith,  738.  231  N. 


Fifth  Ave.,  Chicago,  III. 

O.  B.  Chicago, 


Ship  me  a  No.  2  L.  C.  Smith  F. 
as  described  In  this  advertisement.  I  will  pay  you 
the  $40.00  balance  of  the  SPECIAL  $48.80  purchase 
price  at  the  rate  of  $2.50  per  month.  The  title  to 
remain  in  you  until  fully  paid  for.  It  Is  understood 
that  I  have  five  days  in  whioh  to  examine  and  try 
the  typewriter.  If  I  choose  not  to  keep  it  I  will 
carefully  repack  it  and  return  it  to  the  express  agent. 
It  is  understood  that  you  give  the  standard  guarantee 
for  one  year. 

NAME   

ADDRESS   


Check  the  Job  You  Want! 


Name 


Railway  Mall  Clerk  $900  to  $1800 

Postofflce  Clerk  J800  to  $1200 

.Postofflce  Carrier  $800  to  $1200 

.Rural  Mall  Carrier  $600  to  $1200 

Customs    Positions  $  600  to  $1500 

Internal    Revenue  $  700  to  $1800 

Stenographer     $1000  to  $1500 

Clerk  at  Washington,  D.  C  $  840  to  $1500 


Address   

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429 


EXPERIMENTAL  CHEMISTRY. 

(Continued  from  page  427) 

into  contact  with  some  of  the  gas,  or  over 
some  of  the  warm  solution,  when  im- 
mediately dense  bluish-white  fumes  of  am- 
monium chlorid  are  formed.  (4)  When 
combined  with  acids,  ammonia  is  detected 
by  first  liberating  it  from  its  combination 
with  an  alkali  like  potassium  or  sodium  hy- 
droxid, and  then  applying  one  of  the  above 
tests  for  the  gas ;  or  the  solution  may  be 
acidified  with  hydrochloric  acid  and  solu- 
tion of  platinic  acid  added,  when  a  yellow 
precipitat  of  ammonio-platinic  chlorid,  will 
slowly  separate  in  minute  crystals.  (5) 
Nessler's  Reagent  produces  a  brown  pre- 
cipitate with  ammonium  compounds,  or  if 
in  very  dilute  solution  a  brown  or  yellow 
color.  Nessler's  reagent  is  made  by  adding 
to  a  solution  of  mercuric  chlorid  (corro- 
sive sublimate)  a  solution  of  potassium 
iodid  until  the  precipitate  at  first  formed  is 
nearly  all  redissolved.  Solution  of  potas- 
sium hydroxid  is  then  added  to  strongly 
alkaline  reaction  and  the  liquid  allowed  to 
settle  until  it  becomes  clear,  when  it  is  de- 
canted from  any  sediment. 

Uses  : 

Ammonia  is  widely  used  in  medicine  and 
pharmacy,  in  making  dyestuffs,  in  calico 
printing,  and  in  refrigerating  operations. 
Its  compounds  serve  to  furnish  nitrogen, 
which  is  essential  to  the  growth  of  both 
vegetable  and  animal  life ;  hence  the  use 
of  ammonia  in  fertilizers  for  the  soil.  The 
three  elements  necessary  to  be  restored  to 
the  soil  for  the  raising  of  crops  are  nitro- 
gen, phosphorous,  and  potassium.  Com- 
pounds of  these  three  elements  with  others 
are  made  into  fertilizers  by  manufacturers. 
Ammonium  compounds,  with  some  nitrats, 
furnish  the  nitrogen  on  which  all  higher 
animals  depend  for  the  nitrogenous  ma- 
terial foods. 

The  value  of  ammonia  water  as  a  cleans- 
ing agent  is  due  to  its  ability  to  dissolve 
grease.  Its  basic  properties  also  give  it  a 
use  in  the  laboratory,  whenever  a  volatile 
alkali  is  desirable.  Large  quantities  of 
ammonia  are  used  in  the  manufacture  of 
sodium  carbonat  by  the  Solvay  process. 

Ammonia  is  very  extensively  used  for 
making  artificial  ice  and  for  large  refrig- 
erating and  cold  storage  plants.  When  a 
gas  is  liquefied,  heat  is  liberated,  and  when 
the  liquid  returns  to  the  gaseous  state,  heat 
is  absorbed.  The  process  consists  of  al- 
ternately liquefying  ammonia  and  then 
vaporizing  it.  The  ammonia  gas  is  first 
obtained  from  very  strong  ammonium  hy- 
droxid, and  by  a  compressor  pump,  and  is 
forced  as  a  gas  into  pipes,  called  condens- 
ers, upon  which  cold  water  is  permitted  to 
pass,  which  together  with  the  compression, 
makes  liquid  ammonia,  which  then  passes 
thru  a  valve,  called  the  expansion  valve, 
into  a  series  of  pipes. 

These  pipes  are  immersed  in  a  strong 
brine  of  Calcium  chlorid  solution  (Sodium 
chlorid  not  being  so  good).  As  the  liquid 
ammonia  goes  thru  the  expansion  valve 
and  into  the  tubes  it  again  vaporizes,  and 
in  the  process  withdraws  heat  from  the 
brine,  cooling  it  to  -20  degs.  or  over,  thus 
making  a  freezing  mixture  of  the  brine,  in 
which  tubes  of  pure  water  are  immersed 
and  the  water  frozen.  The  gas  NH3  then 
passes  back  to  the  pump,  where  it  is  used 
again,  the  process  being  continuous. 

Experiment  No.  93 : 

Made  from  Ammonium  Chlorid  and 
Calcium  Hydroxid. 

.  Connect  a  plain  Florence  flask  (125  or 
250  cc.)  having  a  two-hole  stopper  with  a 
thistle  and  delivery  tube  (the  delivery  tube 
in  the  Florence  flask  should  just  pass  thru 
the  stopper,  (but  the  thistle  tube  should  be 


immersed  beneath  the  solution),  to  an  8- 
ounce  bottle,  this  being  fitted  with  a  three- 
hole  stopper.  In  the  second  hole  a  plain 
piece  of  glass  tubing  is  inserted  so  that  it 
projects  over  the  stopper  and  beneath  the 
liquid.  The  third  hole  is  to  accommodate  a 
second  delivery  tube  which  leads  to  the 
second  8-ounce  bottle  which  has  no  stop- 
per. Fig.  84  depicts  this  apparatus.  Both 
8-ounce  bottles  should  be  about  one-fourth 
full  of  water.  The  delivery  tube  from  the 
first  to  second  bottle  should  pass  below  the 
surface  of  the  liquid. 

Put  about  10  grams  of  ammonium  chlorid 
(NHiCl)  on  a  piece  of  paper,  and  on  an- 
other about  8  grams  of  calcium  hydroxid 
(Ca  (OH)2),  recently  slaked  lime  being  the 
best.  Pour  these  successively  into  the  flask, 
add  20  or  25  cc.  of  water,  and  mix  the 
contents  by  rotating  the  flask.  See  whether 
any  odor  comes  from  it.  Then  set  the 
flask  on  an  iron  tripod  or  ring  stand,  with 
asbestos  or  iron  gauze,  make  connections, 
and  apply  heat  for  fifteen  minutes.  If  there 
is  a  tendency  to  froth  up  and  run  over, 
take  away  the  lamp,  and,  if  need  be,  pour 
a  little  water  thru  the  thistle  tube.  In  case 
the  frothing  should  extend  into  the  tubes 
or  bottles,  clean  them  out  and  begin  again. 
Observe  fully  all  phenomena  in  the  flask 
and  try  to  find  an  explanation. 

When  ready  to  stop  the  action  remove 
the  lamp,  take  out  the  stopper,  and  apply 
these  tests  in  rapid  succession  to  the  gas 
in  the  flask.  They  must  be  made  while 
generation  is  progressing.  (a)  Apply  a 
piece  of  both  red  and  blue  litmus  to  the  gas 
and  notice  which  one  is  discolored,  and  con- 
clude what  this  would  indicate,  (b)  Ap- 
ply a  lighted  splint  to  the  gas,  in  order  to 
test  for  the  combustibility  of  the  gas.  (c) 
Test  the  odor,  (d)  Test  with  hydrochloric 
acid  by  pouring  two  or  three  cc.  of  the 
acid  into  a  dish  and  dipping  a  folded  paper 
into  it ;  or  the  test  may  be  made  by  bring- 
ing the  dish  to  the  mouth  of  the  flask  or 
with  a  tuft  of  cotton.  Dense  bluish-white 
(ammonium  chlorid)  fumes  will  appear,  the 
same  being  a  test  for  free  ammonia.  Let 
the  flask  cool  a  few  minutes  after  taking 
away  the  lamp,  then  pour  in  water  from  a 
test  tube,  shake  the  contents,  and  pour 
them  into  a  sink.  Any  adherent  substance 
may  be  removed  from  the  flask  by  using  a 
little  hydrochloric  acid.  Save  the  liquid 
in  the  first  bottle  for  further  tests. 

Experiment  No.  94: 

Properties. — The  positive  radical  or  ion 
of  an  ammonium  salt  is  NH( ;  the  negative 
one  OH.  The  best  test  for  the  positive 
(NHi)  part  is  to  mix  a  little  of  the 
powder  to  be  tested  with  a  equal  amount  of 
slaked  lime  (Ca(OH)2),  heat  the  mixture 
and  obtain  ammonia,  in  case  it  is  an  am- 
monium salt.  A  simple  test  can  often  be 
made  by  rubbing  in  the  palm  of  the  hand  a 
pinch  of  each  substance,  moistened,  and 
noting  the  odor.  The  tests  for  the  nega- 
tive radical  or  ion,  in  addition  to  the  one 
with  litmus,  consists  in  making  insoluble 
hydroxids  as  given  below. 

Experiment  No.  95 : 

Action  on  Ferronj  Sulfate. — Take  a  small 
crystal  of  ferrous  sulfate  (FeS04),  dis- 
solve in  10  cc.  of  water  by  boiling  (it  may 
first  be  pulverized  in  a  mortar,  if  desired), 
then  filter  the  solution  and  add  to  the  fil- 
trat  a  little  of  the  ammonium  hydroxid 
(the  liquid  in  the  first  bottle  of  the  first 
experiment  of  this  paper). 

Note  the  color  and  state  of  the  product. 
Also  note  if  there  is  a  precipitate.  See 
whether  a  solution  of  sodium  hydroxid 
(NaOH)  would  give  the  same  result  as  the 
ferrous  sulfate  solution.  Try  also  the 
action  of  potassium  hydroxid  (KOH)  in 
solution. 


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THE  ELECTRICAL  EXPERIMENTER 


October,  1917 


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Experiment  No.  96: 

The  Ammonia  Fountain.    Ammonia  Gas 

(NHs).  Tests  and  Properties. — Various 
tests  were  applied  to  the  gas  ammonia  in 
experiment  No.  93.  The  simplest  one  is  the 
odor  test,  which  is  very  characteristic  of 
this  gas.  Its  action  on  litmus,  and  inertness 
to  the  combustion  test,  do  not  distinguish 
it  from  other  substances.  The  litmus  test 
is  a  test  for  the  base  OH. 

To  show  its  action  on  water,  collect  a 
bottle  full  of  it  by  upward  displacement  by 
use  of  the  apparatus  shown  in  Fig.  85,  either 
from  a  generator  or  by  boiling  about  20  cc. 
of  strong  ammonium  hydroxid.  The  lat- 
ter will  give  the  purer  and  stronger  gas. 
Have  the  delivery  tube  from  the  generator 
reach  close  to  the  top  of  the  inverted  bot- 
tle. Close  the  mouth  of  the  bottle  with  a 
one-hole  stopper  carrying  a  glass  tube,  as 
soon  as  it  is  filled  with  gas  (which  is  made 
apparent  when  the  odor  is  observed  around 
the  bottle),  and  at  once  thrust  the  out- 
side end  of  the  glass  tube  into  a  dish  or 
beaker  of  water,  having  the  bottle  in  an 
inverted  position  till  action  takes  place. 
(Fig.  86  illustrates  the  apparatus  for  use 
for  the  Ammonia  Fountain).  As  the  name 
implies,  the  ammonia  will  absorb  the  water 
from  the  beaker,  thereby  drawing  it  up  into 
the  bottle  with  such  force  that  a  miniature 
fountain  will  be  formed.  Unless  the  am- 
monia is  unmixed  with  much  air  the  ex- 
periment will  not  be  a  success.  By  having 
a  few  drops  of  red  litmus  solution  in  the 
water  in  the  dish  or  beaker  into  which  the 
tube  is  thrust,  a  double  test  may  be  made. 
Observe  any  color  phenomena  when  the 
litmus  is  introduced  into  the  beaker. 

The  reader  may  have  heard  or  read  of 
reversible  reactions  and  never  stopt  to 
inquire  as  to  their  meaning.  This  experi- 
ment is  an  excellent  illustration  of  a  re- 
versible reaction.  A  reversible  reaction  is 
one  in  which  the  factors  become  the  pro- 
ducts and  the  products  the  factors.  Heat- 
ing ammonium  hvdroxid  (NH4OH)  gives 
Water  (H20)  and  Ammonia  (NHs).  Re- 
verse the  experiment  by  passing  Ammonia 
(NH3)  into  water  and  you  have  ammo- 
nium hydroxid  (NH4OH).  Thus  the  re- 
action goes  either  way,  according  to  the 
conditions,  or  may  go  both  ways  till 
equilibrium  is  established. 

Experiment  No.  97: 

Diffusion  and  Absorption. — Take  two 
small  flasks  (125  cc.)  each  carrying  a  one- 
hole  stopper,  and  connect  them  by  means 
of  short  glass  tubes,  connected  with  a  rub- 
ber stopper,  as  shown  in  Fig.  87.  Into  one 
pour  30  or  40  cc.  of  water  and  into  the 
other  the  same  volume  of  ammonium  hy- 
droxid. The  tubes  should  not  pass  below 
the  surface  of  the  liquid,  as  we  are  to 
deal  with  a  gas.  Allow  them  to  stand  in 
this  manner  for  a  week  or  so,  then  test 
the  liquid,  both  with  litmus  and  Nessler's- 
Reagent,  in  the  bottle  which  at  first  con- 
tained the  water  only.  Observe  any  re- 
sults. This  would  show  that  the  ammonia 
(NH3)  from  the  hydroxid  (NH.OH) 
past  over  the  tube  and  again  formed  an 
ammonia  solution  with  the  water  which 
was  in  the  flask. 


THAT   PERPETUAL  MOTION. 

{Continued  from  page  407) 

only  run  forty  seconds  or  so  at  each  descending. 

Consequently,  the  dynamo  would  not  have  enough 
time  to  charge  the  batteries,  regardless  of  the  num- 
ber of  cars  or  how  often  they  run. 

Also  the  continual  charging  and  discharging  of 
the  batteries  at  such  minute  intervals,  would  not 
give  them  sufficient  time  to  charge  properly,  and 
consequently  the  cars  would  not  run  three  minutes, 
much  less  for  years  as  was  suggested. 

EDWARD  JAMES  VAN  ALLEN, 

Stamford,  Conn. 


Lets  Nickleplate  the  "Superstructure"!'! 

In  the  first  place  you  must  think  of  the  super- 
structure upon  which  the  track  is  laid.  Without 
paint  and  proper  care  it  would  soon  rot.  The  cars 
also  would  need  attention. 

Altho  the  cars  charge  the  storage  batteries  when 
going  down  grade,  they  would  use  up  a  great  deal 
more  current  going  up.  At  which  rate  the  current 
would  soon  be  used  up.  The  distilled  water  in  the 
storage  batteries  would  _vaporate,  after  which  the 
"bats"  would  not  work. 

The  fridion  wheel,  third-rail  contact  shoe  and 
belt  would  also  wear  out,  after  all  of  which  the 
device  would  stop  going. 

HENRY  A.  McCOMAS, 

Blue  Ridge  Summit,  Pa. 


To    "Rub"    Or    Not    to    "Rub,"    That's  the 
Question!! 

In  charging  the  cells  receive  a  positive  and 
negative  charge.  Then  when  the  car  goes  uphill 
the  batteries  should  discharge,  but  in  discharging 
the  batteries  change  poles.  This  would  tend  to 
make  the  car  go  backwards  on  the  hill,  so  that  the 
batteries  would  hinder  more  than  help.  The  dy- 
namo is  not  perfect,  for  it  can  never  cut  the  lines 
of  force  of  all  its  poles  and,  consequently,  can 
never  generate  enough  power  to  be  100  per  cent 
perfect.  Friction  (which  is  always  present),  in 
rubbing  places  would  make  the  car  stop. 

SIDNEY  KILLIAN, 
642  Susque  Avenue, 

Sunbury,  Pa. 


Oh  Carl,  How  Could  You  Be  So  Cruel  in  100 
Words!! 

This  device  can  impossibly  keep  going  for  years, 
due  to  the  fact  that  no  storage  battery  ever  built 
could  or  can  last  for  any  number  of  years  since  its 
plates  or  elements  would  be  decomposed  by  the 
electrolyte  thereby  decreasing  the  efficiency  of  the 
cells  so  greatly  that  they  woul  discontinue  to  do 
their  work  faithfully.  Another  thing  is  that  stor- 
age batteries  must  be  charged  at  an  even  rate  of 
current,  and  in  this  case  it  would  not_  be.  Also 
the  cars,  while  descending,  would  be  going  so  fast 
as  to  overload  the  dynamo,  thereby  possibly  burning 
out  its  armature, 

CARL  HAARMANN, 
New  Holstein,  Wis. 


Washing  Without  Work 

This  truly  wonderful  machine  has  revolu- 
tionized washing.  It  fits  in  any  stationary  wash- 
tub  and  does  all  the  washing,  rinsing  and  wring- 
ing by  electricity.  All  you  need  do  is  turn  on 
the  switch.  The  clothes  are  washed  cleaner  and 
whiter  than  ever  before  and  in  the  most  sani- 
tary way. 

The  machine  washes  delicate  laces  and  lin- 
gerie without  injury ;  also  heavy  blankets  and 
small  rugs.  Clothes  washed  in  it  last  six  times 
as  long  as  those  washed  on  the  rubbing  board  or 
at  laundries. 


MODE 


HOME 
E  R 


FITS   IN  ANY"  TUB" 


This  js  the  onlv  washing  machine  of  its  land  that  fits 
and  operates  in  stationary  washtubs  and  stores  in  the 
tub  out  of  the  way,  when  not  in  use.  It  is  a  great 
boon  in  apartments  and  small  kitchens  where  there  is 
no  room  for  a  heavy,  bulky  washing  machine,  in  the 
way  all  the  week. 

The  Modern  Home  Washer  saves  its  cost  many  times 
over  each  year  in  washwoman  expense  and  clothes  sav- 
ings. It  solves  the  servant  problem  and  the  cost  of 
electricity  is  only  about  three  cents  for  a  week's  washing. 

Tested  and  approved  by  Good  Housekeeping  Institute 
and   the  Tribune   Institute.     Awarded    a   medal  at 
Panama  Pacific  Exposition.    Portable  machine  for  use 
where  there  are  no  stationary  tubs. 
Electric,  Portable  Metal  Tub  Type,  complete. .  .$1 10.00 

Electric.  Stationary  Tub  Type,  complete   90.00 

Hand  Power,  Stationary  Tub  Type   15.00 

No  extra  tub  to  pay  for. 
Write  for  Catalog  today. 
Home  Devices  Corporation 

Bush  Terminal  Bldg.  5 
99  Thirty-Fifth  Street  Brooklyn,  N.  Y. 


You  benefit  by  mentioning  "The  Electrical  Experimenter"  when  writing  to  advertisers. 


October,  1917 


THE  ELECTRICAL  EXPERIMENTER 


431 


9 


Scientific  Exchange  Columns 

TTNDOUBTEDLY  you  have  at  the  present  time  some  things  for  which  you  have  no  further  use.  Do  you  wish  to  exchange  them  for  something, 
V  for  which  you  have  immediate  use?  There  is  no  surer  and  quicker  way  to  do  this  than  by  advertising  your  articles  in  these  columns. 
The  Very  people,  the  Only  people,  who  could  possibly  have  a  use  for  your  things  read  this  journal.  More  than  75,000  interested  people 
will  see  your  ad.  It  is  furthermore  the  cheapest  advertising  medium  for  you  in  the  country.  Dealers'  advertising  accepted  in  Opportunity 
Exchange  Columns  only. 

The  rates  are:     Three  cents  per  word  (name  and  address  to  be  counted),  minimum  space  3  lines.     Count  about   7  words  to  the  line. 
Remittance  must  accompany  all  orders.     No  advertisement  for  less  than  50c.  accepted. 

We  reserve  to  ourselves  the  right  to  refuse  any  advertisement  which  we  consider  misleading  or  objectionable.     Advertisements  for  the 
November  issue  should  reach  us  not  later  than  Sef/tember  25th. 

The  Classified  Columns  of  "The  Electrical  Experimenter"  Bring  Positive  Results. 
Subscribers  experiencing  trouble  in  dealing  with  any  advertiser  should  notify  the  publisher  very  promptlv. 

OVER  79,000  PEOPLE  READ  THIS  JOURNAL 

kg .  '"^ 


CASH  PAID  for  a  set  of  Bound  Volumes  be- 
longing to  I.  C.  S.  Electric  Engineering  Course 
(Part  Two).    H.  Walton,  Amigari,  Ontario,  Can. 


WANTED— Your  old  Wireless  Apparatus.  I 
also  have  a  $50  Wireless  Set  to  trade  for  a  motor- 
cycle. Enclose  stamp.  Lawrence  Johnston,  Fair- 
field, Illinois. 


FOR  SALE— 15,000  meter  coupler,  3,500  meter 
receiving  set,  two  3,000  ohm  headsets,  two  20  ohm 
telegraph  sets,  telephone  transmitter.  Write  for 
photo  and  description.  F.  B.  Dadisman,  Inde- 
pendence, West  Va. 


HAVE— New  Western  Electric  table  fan  ($25). 
Want  typewriter  and  wireless  goods.  Mack  Sim- 
mons, Van  Alstyne,  Texas. 


FOR  SALE  CHEAP— One  new  Power's  6-A  Mo- 
tion Picture  Outfit,  used  four  weeks.  Would  con- 
sider an  immediate  cash  offer.  Austin  Miller, 
Erwin,  Tenn. 


FOR  EXCHANGE— $40.00  worth  wireless  and 
electrical  apparatus.  Would  like  8  x  10  view  cam- 
era or  other  photographic  goods.  Write  for  list  of 
apparatus  and  say  what  you  have.  K.  R.  Sipple, 
166  Whitney  PI.,  Buffalo,  N.  Y. 


FIRST  MONEY  ORDER  GETS  THESE  BAR- 
GAINS—D.  C.  500  V.  Y2  H.  P.  Standard  Dynamo, 
$24.50.  Robbins  1-16  H.P.  500  V.  new  enclosed 
motor,  $8.75.  Both  fine  for  radiotelephones.  Smith 
motorwheel,  $27.25.  Tubular  audion,  $4.  Mignon 
Receiving  Set,  $4.90.  P.  Edelman,  1802  Hague, 
St.  Paul,  Minn. 


FOR  SALE — Electron  Relay  and  cabinet  com- 
plete, $10.  New  Electron  Relay,  $4.  1  K.  W. 
Glass  Plate  Transmitting  Condenser,  $3.  5  H.P. 
motor  starting  box,  $4.    Ralph  LefHer,  Tiffin,  Ohio. 


FOR  SALE — New  3  speed  bicycle  practically 
new;  2  speed  Hub;  new  Camera  and  5x7  enlarger, 
developer  and  printing  set.  No.  4  Erector;  1 
Transformer;  2  motors.  Send  for  description. 
Clair  Miller,  Wilmington,  Ohio. 


FOR  SALE— 2,500  Meter  Loose  Coupler;  un- 
mounted 43  plate  Variable;  unmounted  Detector; 
Brandes  2,000  ohm  Phones;  lji"  Spark  Coil;-Jove 
Key.  Expressage  extra.  Walter  J.  Schneider, 
R.  R.  2,  Mason  Rd.,  Hamilton,  Ohio. 


ABOUT  1,000  copies  specifications  and  drawings 
for  all  U.  S.  Radio-communication  patents  from 
beginning  to  date;  will  sacrifice  complete  collection 
for  $55.    P.  Edelman,  1802  Hague,  St.  Paul,  Minn. 


WANTED— An  Amco  or  Tesla  Transformer. 
Have  apparatus  to  trade.  Write  for  my  list.  Robt. 
Fairchild,  Minden  Mines,  Mo. 


WANTED^One  H.P.  Gas  Engine,  Redemotor 
preferred,  good  condition,  cash.  Sell — Harley  twin, 
run  four  thousand  miles,  thirteen  model,  ninety 
dollars,  ready  to  ride,  bargain.  Write  me.  H.  P. 
Rea,  Carrollton,  Mo. 


FOR  SALE— 15,000  meter  Navy  Type  Loose 
Coupler,  $10;  200  ohm  Phones,  $5;  Galena  and 
Electrolytic  Detectors;  Y%"  Spark  Coil,  75c.; 
Shocker,  50c,  and  $3.50  Telegraph  Set,  $1.  Har- 
old Hammer,  3225  23rd  Ave.,  So.,  Minneapolis. 


FOR  SALE— Hudson  Audion  Amplifier  Bulb, 
new,  $500;  )4"  Spark  Coils,  $1.25;  large  Accurate 
Voltammeter,  $2;  also  chemicals.  All  answered. 
J.  C.  Swimmer,  1904  Park  PI.,  Brooklyn,  N.  Y. 


WILL  SELiL  OR  TRADE— Complete  set  Cyclo- 
pedia of  Applied  Electricity  in  A-l  condition.  R. 
O.  Miles,  Wyanet,  111. 


WANTED— 150  ohm  relay,  Vibroplex,  Omni- 
graph,  key,  sounder,  Audion,  15,000  meter  coupler, 
small  coupler,  storage  battery,  high  tension  con- 
denser, rotary  gap,  ground  switch,  rheostat.  Cash 
or  trade.  Write  quick,  giving  best  price,  to  Geo. 
Rozum,  Mitchell,  S.  D. 


WANTED — For  cash  or  trade,  an  Edison  Phono- 
graph with  records.  Give  condition,  terms,  etc. 
Frederick  Towns,  Winchester  St.,  Keene,  N.  H. 


FOR  SALE— $25  Erector  Set  complete  in  A-l 
condition,  used  once,  $20.  A.  E.  La  France,  40 
Ely  Street,  Holyoke,  Mass. 


|  "WANT  TO  SWAP"?  | 

H  Do  you  realize  that  these  "Scientific  Ex-  =1 

gj  change  Columns"  are  the  World's  most  re-  |j{ 

ii  nowned   "Swap"   market?      "THE  ELEC-  Hj 

B  TRICAL  EXPERIMENTER"  prints  79,800  |J 

=  copies  of   this   issue;   that   means   that   at  gj 

Hj  least    160,000    readers    see    this    page   and  pj 

U  probably  a  great  many  more.    Our  readers  p| 

=  who    advertise    here   seldom    advertise   the  Uj 

H  same  thing  twice — usually  within  five  days  pj 

g|  after  the  issue  is  out  the  advertised  article  g 

pi  has  been  sold,  or  swapped.    The  many  testi-  pi 

H  monials  which  we  print  here  from  time  to  pj 

"  time  are  ample  proof  of  the  almost  miracul-  11 

B  ous  pulling  power  of  three  columns.  pj 

PJ  Look  around  in  your  attic  or  workshop  pj 

=  and  you  will  find  dozens  of  long  forgotten  =J 

B  articles,  useless  to  you  now,  but  very  use-  pj 

Es  fill  to  someone  else.    At  a  ridiculously  low  PJ 

Eg  cost  you  can  either  sell  or  swap  such  articles,  pj 

HJ  And  remember  this  fact:  The  U.  S.  Postal  11 

=  Laws  protect  you.     No  one  can  "do"  or  pj 

pj  cheat  you.     Of   3,410   "ads"  published  in  pj 

11  these  columns  during  the  past  five  years,  pj 

11  only  twelve  complaints  were  reported  to  us,  m 

:  and  each  and  every  one  was  adjusted  to  =J 

=  the  full  satisfaction  of  the  complainant. 

PJ  It  matters  not  if  you  have  old  books  or  pj 

pj  magazines,  a  kodak,   electrical  or  chemical  | 

pj  apparatus,    scientific    instruments,    bicycles,  =J 

pj  typewriters,   moving  picture  machines,   air  pj 

pj  rifles,    watches,    structural    toys,    etc.,    etc.  =J 

=J  All  these  and  countless  others  can  be  speed-  Ijj 

pj  ily  disposed  of  here.     Try  it  and  be  con-  jj 

pj  vinced. 


FOR  SALE — I  C8  Electrical  Engineering 
Course.  9  Vol.  in  goods  condition.  Cost  $100. 
The  best  offer  takes  them.  Geo.  Fehrenback,  76 
Hancock  Ave.,  Jersey  City,  N.  J. 


FOR  SALE — Wireless  Sending  and  Receiving 
Apparatus.  Large  marble  switchboard,  miscel- 
laneous other  electrical  apparatus,  books,  chemicals. 
Want'  vacuum  and  X-ray  tubes  AC  and  DC  meters. 
Ralph  Batcher,  131  Hyland,  Ames,  Iowa. 


FOR  SALE— $50.00  buys  $200.00  complete, 
good  as  new,  Edison  Moving  Picture  Machine. 
135  feet  of  movie  picture  fTlm  for  toy  moving  ma- 
chine. $1.25,  30  foreign  coins,  $2.00.  Herman 
David,  711  South  Kedzie  Ave.,  Chicago,  111. 


A  SNAP — Owing  to  dissolution,  $40  takes  one 
Edison  Motion  Picture  Machine,  good  order.  En- 
terprise P.  &  N.  Co.,  Kewanee,  111. 


SYMPHONY  PHONOGRAPH  with  about  $25 
worth  new  Victor  and  Columbia  records,  all  good, 
$16.    P.  Edelman,  1802  Hague,  St.  Paul,  Minn. 


FOR  SALE — Electric  Therapeutic  Apparatus 
Machine.  Second-hand,  in  good  condition,  used  by 
physicians  for  rheumatism  and  circulation.  Will 
sell  at  a  very  reasonable  price.  John  Ferguson, 
113  West  63rd  St.,  New  York  City;  home,  364 
West  57th  St. 


WANTED— Copy  of  book  "Michael  Faraday,  His 
Life  and  Work"  by  Sylvanus  Thompson.  Also  an 
ohmeter  of  the  Roller-Smith  type  or  a  Wheatstone 
bridge;  must  be  in  first-class  condition,  and  include 
galvanometer.  H.  W.  Secor,  c/o  Electrical  Ex- 
perimenter, 233  Fulton  St.,  New  York  City. 


MOTION  PICTURE  MACHINE,  Power's  No.  6, 
no  lens  or  rheostat;  automatic  steropticon,  carries 
eighteen  slides,  uses  motor;  nineteen  sets  colored 
song  slides;  good  make  snare  drum;  cash  or  trade. 
High-tone  rotary  $9;  Murdock  oscillation  $2.75. 
Want  reliable  wireless  goods.  New  $7.50  Racine 
A.  K.  Utility  Motor,  $6.50.  Verner  Hicks,  Marion, 
111.  * 


FOR  SALE  OR  EXCHANGE— 1915  Indian 
Motorcycle,  in  excellent  condition,  2-speed,  2- 
cylinder,  9  H.P.,  cost  $275.  Full  equipment,  tires 
almost  new.  Will  sell  cheap.  Laverne  Bushnell, 
Hanover,  N.  H. 


FOR  SALE  OR  EXCHANGE— Remington  No. 
6  Typewriter,  $14;  $8  Drafting  Set,  $5;  Set  of 
"Hawkin's  Electrical  Guides,"  $8.  Write  for  list 
of  other  electrical  and  mechanical  books.  Want 
cash  or  good  camera,  or  what  have  you?  P.  Plat- 
zer,  119  E.  Grand  Ave.,  Chicago,  111. 


FOR  SALE — High-grade,  second-hand  wireless 
apparatus  for  sale  at  a  bargain  price.  Write  for 
list  and  information.     Eldred  Hall,  Solvay,  N.  Y. 


LARGE  WIRELESS  receiving  set  with  aerial, 
$12.     Robert  Bowers,  c/o  F.  White,  Great  Neck, 

N.  Y. 


TRADE  FOR  MOTORCYCLE— $200  worth  of 
wireless  instruments  or  sell.  Denecke,  1539  Ave. 
A.,  New  York. 


EXCHANGE— Bicycle,  toy  transformer,  and 
electric  train  for  Brandes  Superior  Phones,  110 
volts  a.c.  motor  or  gas  engine.  Frank  Low,  Jr., 
103  S.  Pine  St.,  Pauls  Valley,  Oklahoma. 


SELL  OR  EXCHANGE— New  3-A  Kodak,  $36 
Meccano,  4-60  Storage.  Send  for  list.  Want 
Thordarson  and  other  apparatus.  Huff,  915  Camp- 
bell St.,  Williamsport,  Pa. 


SMALL  screw  cutting  lathe,  3  speed  lathe  and  a. 
Boley  watchmaker's  lathe  for  sale  or  exchange. 
Ralph  C.  Morse,  P.  O.  Box  147,  Foxboro,  Mass. 


FOR  SALE— $50  set  Harvard  Classics,  51  books, 
new,  $30;  also  15"  spark  coil  without  condensers. 
If  interested  write,  will  send  photo  of  coil  and 
open  bids.  Any  for  less  than  $40  ignored.  Harry 
J.  Frenz,  740  Franklin  Ave.,  Wilkinsburg,  Pa. 


BARGAINS— 6,000  meter  Navy  Type  Coupler, 
$4.50.  All  kinds  of  wireless  apparatus,  all  new. 
Write.     Walter  Johnson,  Salem,  Nebr. 


432 


THE  ELECTRICAL  EXPERIMENTER 


October,  1917 


Opportunity  Exchange 

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lite  are  hard  to  rind  and  wortj  going  after— these  little  ads  illustrate  that  point;  you  alone  will  be  the  real  loser  if  you  don't  take  th< 


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advertising  agency. 

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accepted. 

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ly prize  competitions;  print  criticisms;  many  unique 
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BOOKS — Scientific  and  wireless  supplied.  Let 
us  know  what  you  want  and  we  will  quote  you. 
Experimenter  Pub.  Co.,  233  Fulton  St.,  New 
York  City. 

A  BINDER  for  THE  ELECTRICAL  EXPERI- 
MENTER  will  preserve  your  copies  for  all  time. 
Price,  50c.  Postage  on  3  lbs.  is  extra.  Send  for 
one  today.  Experimenter  Publishing  Co.,  233  Ful- 
ton St.,  New  York  City. 

FIRE  SALE  OF  SLIGHTLY  DAMAGED 
BOOKS.  Due  to  fire  in  our  stock  rooms,  a  great 
many  of  our  books  were  water  stained,  but  not 
otherwise  damaged.  Rather  than  dispose  of  them 
to  dealers  we  prefer  to  give  our  readers  the  bene- 
fit. Look  at  this  list!  Our  celebrated  Wireless 
Course,  160  pages,  400  illustrations;  Experimental 
Electricity  Course,  160  pages,  350  illustrations;  How 
to  Make  Wireless  Sending  Instruments.  These 
three  books  for  $1.00  prepaid.  Regular  selling 
price  of  these  three  books  is  $2.50.  We  guarantee 
"vou  will  be  satisfied.  Experimenter  Publishing  Co., 
"Inc.,  233  Fulton  St.,  New  York  City. 

OLD  E  E.  BACK  NUMBERS— We  have  some 
valuable  old  E.E.  back  numbers  on  hand  as  per 
list  below: 


1915. 
Tan.    .  . 
Feb.   .  . 
March 
April  . 
May   . . 
Tune  . . 
July  ... 
August 
Sept.  .. 
Oct.  ... 
Nov.  . . 
Dec.  .  . 


March    .  .price  each  $.20 

.  price  each  $.25  ,  April    ..."      "  " 

"      "      "  "  May  ....    "      "  " 

.    "     "      "  June  ....    "      "  " 

  July    ....    "      "  " 

"  August    ..    "  " 

.     "      '*       "        Sept   " 

.     "      "      "        Oct   " 

.    "      "      "        Nov   "      "  " 

"      "       Dec   ' 

"      "      "  1917. 

Jan              "      "  .15 

.    "      "      "        Feb   "  " 

March  ....    "      "  " 
1916.                                 April    ..."  " 

Jan               "      "    .20        May  .  . .  .    "      "  " 

Feb              "     "      "       June  ....    "     "  " 

July               "      "  " 

We  can  fill  orders  at  once  upon  receipt  of  your 
remittance  and  if  you  have  not  these  numbers  al- 
ready now  is  your  chance  to  get  them  as  they 
probably  will  be  snapped  up  very  quickly.  Ex- 
perimenter Publishing  Co.,  233  Fulton  St.,  New 
York  City. 

BUSINESS  OPPORTUNITIES 

BUILD  a  profitable  money-making  business  of 
your  own.  We  will  instruct  you  to  manufacture 
articles  that  sell  rapidly.  We  will  teach  you  how 
to  make  Silver-Plating  Powder,  Liquid  Court-Plas- 
ter, Straw-Hat  Bleach,  Re-Silvering  Mirrors,  Dress- 
ing and  Polish  for  tan  shoes,  Luminous  and  Oilcloth 
Paints,  Toothpaste  for  Collapsible  Tubes,  Soap- 
Bubble  Liquid.  .  All  these  formulas  with  instruc- 
tions, onlv  50c.  Sidney  Specialty  Co.,  233  S.  Fulton 
St.,  New  York  City. 


CHEMICALS 


URANYL  CHLORID  (Radio-Active)  pure,  U 
Oz.,  75c;  Uranyl  Bromid  (Radio-Active)  pure,  % 
oz.,  90c;  Uranyl  Oxid  (Radio-Active)  pure,  J4  °z-> 
85c;  Uranium  Metal  fused  (Radio-Active)  1  gram, 
$2.  The  above  are  guaranteed  genuine.  Robert 
j.  Hanchett,  Nestor,  Cal.  

STOP  playing.  Experiment  systematically  with 
real  chemicals  and  apparatus.  Six  cents  brings 
catalogue.  Clarence  Appel,  Mathews  Avenue, 
Knoxville,  Pittsburgh,  Pa. 

HELP  WANTED 

WAR  MEANS  THOUSANDS— Men,  women,  18 
or  over,  wanted  by  Government  for  excellent  clerical 
positions,  $100  month.  Steady  work.  Short  hours. 
Life  appointment.  Common  education  sufficient. 
Write  immediately  for  free  list  of  positions  now 
obtainable.  Franklin  Institute,  Dept.  G-27,  Roches- 
ter, N.  Y. 


Gentlemen:  H 
When  it  comes  to  results  ths  "E.E."  g 
is  all  broke  out  with  it.    Rec'd  an  m 
answer  with  the  same  mail  that  I  got  B 
the  magazine  on.  M 
Yours  truly,  g 
Bernard  Brown.  = 


MM 

BE  A  DRAFTSMAN— Big  pay;  tremendou9 
demand.  Study  at  home;  complete  course;  draw- 
ing instruments  FREE.  Our  students  filling  good 
positions  as  Draftsmen  and  Chief  Draftsmen  with 
Government  and  private  concerns.  We  help  you 
secure  position  when  qualified.  Columbia  School 
of  Drafting,  25  McLachlen  Bldg.,  Washington, 
D.  C. 


MISCELLANEOUS 

ELECTRICIAN  and  Armature  Winders.  Send 
$1.50  for  16  blue  prints  of  motor  windings,  10  A.  C. 
Single,  two  and  three  phase  and  6  D.  C.  Or,  20 
A.  C,  6  D.  C.  and  6  rotary  converter  drawings, 
$2.25.  Winding  made  easy.  Superior  Electric 
Co.,  Pittsburgh,  Pa.    Lock  Box  1372.  

MINERALS — Two  cents  brings  catalogue. 
Clarence  Appel,  Mathews  Avenue,  Knoxville, 
Pittsburgh,  Pa.  

BIG  BARGAIN  IN  TENNIS  RACKETS— 
We  have  a  small  supply  of  Tennis  Rackets,  made 
by  one  of  the  largest  firms  in  the  country,  on  hand 
which  we  will  close  out  at  the  following  prices: 
No.  2375 — Extra  best  Tennis  Racket,  $5  grade,  air 
dried  ash,  popular  long  oval  form,  concave  walnut 
wedge,  superior  quality  of  gut;  each,  $2.75. 
No.  2377 — First  grade  Tennis  Racket,  second 
growth  ash,  walnut  and  maple  throat,  very  good 
grade  of  gut;  handle  of  cedar  with  leather  cap;  a 
$3.25  grade;  each  $1.85. 

No.  2376 — Medium  grade  Tennis  Racket  made  of 
the  same  stock  as  No.  2377  except  the  gut.  A  per- 
fect $2.25  grade.  Ideal  for  beginners.  Each  $1.35. 
Shipping  weight  of  each  size  two  pounds.  Send 
for  one  today.  Our  stock  is  limited  and  policy  is: 
"First  Come,  First  Served."  Don't  forget  to  in- 
clude money  for  postage,  or  we  ship  express  collect. 
The  Electro  Importing  Co.,  233  Fulton  St.,  New 
York  City. 

MACHINERY  FOR  SALE 

SEND  for  circular.  12  in.  Semi-quick  Change 
Gear,  Screw  Cutting  Lathe.  Compound  Rest,  Power 
Cross  Feed,  Complete  $200.  Western  Machinery 
Co.,  Cincinnati,  Ohio. 


CASTINGS  for  "Machine-shop"  Bench  Lathe, 
6  in.  swing  C.  to  C.  Complete  set  only,  $7.  Louis 
E.  Schwab,  3708  Brooklyn,  Cleveland,  Ohio. 

PATENT  ATTORNEYS 

IDEAS  WANTED— Manufacturers  are  writing 
for  patents  procured  through  me.  Four  books 
with  list  hundreds  of  inventions  wanted  sent  free. 
I  help  you  market  your  invention.  Advice  Free. 
R.  B.  Owen,  130  Owen  Bldg.,  Washington,  D.  C. 

PATENTS— R.  Morgan  Elliott  &  Co.,  Patent 

Attorneys,  Mechanical,  Electrical  and  Chemical 
Experts.  716-724  Woodward  Bldg.,  Washington,  D.C. 

PATENTS — Without  advance  attorney's  fees. 
Not  due  until  patent  allowed.  Send  sketch  for 
free  report.  Books  free.  Frank  Fuller,  Wash- 
ington, D.  C. 

PATENTS  worth  while.  No  free  booklets,  no 
premiums,  no  trading  stamps — nothing  but  good 
service.  Samuel  Herrick,  Master  of  Patent  Laws, 
Washington,  D.  C. 

 PHONOGRAPHS  

BUILD  YOUR  OWN  PHONOGRAPH  or  manu- 
facture them  for  profit.  Drawings,  instructions, 
etc.,  Twenty-five  Cents.  Satisfaction  guaranteed. 
Circular  free.  Associated  Phonograph  Co.,  Dept. 
E,  Cincinnati. 

PHOTOGRAPHY 

MOVING  PICTURE  FILMS  three  feet  long 
10c  each  or  50  ft.  for  50c.  Larger  quantities  at 
rate  of  lc  per  foot.    L.  E.  Adams,  Lewiston,  Me. 

CUT  PRICE  developing,  printing  and  enlarging 
for  films,  film  packs,  and  plates.  Send  stamp  for 
price  list.  X.L.  Photo  Co.,  24  Franconia  St., 
Worcester,  Mass. 

WE  HAVE  a  limited  number  of  beautiful  art 
pictures  of  the  following  famous  electrical  men  on 
hand.  Nikola  Tesla,  Thomas  A.  Edison,  Guglielmo 
Marconi,  Charles  P.  Steinmetz  and  Reginald  A. 
Fessenden.  These  make  a  handsome  decoration 
for  any  laboratory  or  workshop  and  should  be- 
prominently  displayed.  Price  for  five,  prepaid, 
25c.  Experimenter  Pub.  Co.,  233  Fulton  St.,  New 
York  City. 

STAMPS 

STAMPS— 75,  all  different,  free.  Postage,  2c. 
Mention  paper.    Quaker  Stamp  Co.,  Toledo,  Ohio. 

FREE— 12  JAPAN  AND  5  UNUSED  CUBA 
to  applicants  for  our  approvals.  Postage,  2c. 
Write  for  premiums. 

300    Different  30c. 

100    Different   5c. 

Universal  Stamp  Co.,  Mt.  Clemens,  Mich. 

TELEGRAPHY 

TELEGRAPHY — both  MORSE  AND  WIRE- 
LESS, also  STATION  AGENCY,  taught  quickly. 
TREMENDOUS  DEMAND— much  greater  than 
supply — PERMANENT  POSITIONS  SECURED. 
BIG  SALARIES  —  recently  raised.  IDEAL 
WORKING  CONDITIONS— short  hours,  vaca- 
tions with  pay,  sick  and  death  benefits,  etc. — pre- 
vailing. GREAT  OPPORTUNITIES  FOR  AD- 
VANCEMENT. WOMEN  OPERATORS  also 
greatly  desired  by  Railways  and  Western  Union. 
Tuition  reasonable.  Cheap  living  expenses — can 
be  earned.  Oldest  and  largest  school — established 
43  years.  Endorsed  by  railway,  Western  Union 
and  Marconi  Telegraph  Officials.  Large  illustrated 
catalogues  free.  Correspondence  courses  also. 
Write  today.  ENROLL  IMMEDIATELY.  Dodge's 
Institute,  Lone  St.,  Valparaiso,  Indiana. 


TYPEWRITERS 


TYPEWRITERS,  all  makes  factory  rebuilt  by 
famous  "Young  Process."  As  good  as  new,  look 
like  new,  wear  like  new,  guaranteed  like  new. 
Our  big  business  permits  lowest  cash  prices.  $10 
and  up.  Also,  machines  rented — or  sold  on  time. 
No  matter  what  your  needs  are  we  can  best  serve 
vou.  Write  and  see  now.  Young  Typewriter  Co., 
Dept.  362,  Chicago. 


ucceed  Through  Elecfriciiy 


This  interesting  story 
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further  advance  himself  in  the 
Electrical  field  should  have  a 
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John  Kelley 
116  Union  St.,  Newark.  O. 

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college  training  and  even  in 
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do  not  believe  there  is  a  better 
set  of  books  in  the  market  to- 
day." Lloyd  D.  Huffman 
Dayton,  O. 

"  We  consider  Hawkins  Elec- 
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references  in  the  market." 
Koggle  Electric  Works 

Monterey,  Cal. 
"Hawkins  surely  knows  the 
art   of  condensing  informa- 
tion."      Elbridge  F.  Ball 
Buckland.  Conn. 


This  is  the  Electrical  age. 
Electricity  now  controls  more 
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A  FEW  OF  THE  SUBJECTS 

Magnetism— Induction— Experiments  —  Dynamos 
— Electric  Machinery — Motors — Armatures — Arm- 
ature Windings— Installing  of  Dynamos — Electri- 
c  I  Instrument  Testing  —  Practical  Management 
of  Dynamos  and  Motors — Distribution  Systems — 
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Ready  Reference  Index  of  the  10  numbers. 


Theo.  Audel  &  Co. 
72  Fifth  Ave.,  N.  ¥. 

Please  send  me  for 
FREE  examination 
H  a  w  kins  Electrical 
Guides  (Price  $1.00  each). 
Ship  at   once   prepaid  the 
TEN  numbers.  If  satisfactory 
I  agree  to  send  you  $1.00  each 
month  until  paid. 


72  Fifth  Ave. 
NEW  YORK 


Business  Address 


Residence 


Refl  Brence 


Oct.  E.E. 


You  benefit  by  mentioning  "The  Electrical  Experimenter"  whan  vrriiina  in  uiifcrtisers. 


lA/AMTCn  thousands  of  Trained  Men  for  the 

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Bud  Morriss 

Chief  Instructor 

American  School  of  Aviation 

This  well-known  aviator 
personally  guides  the  prog- 
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431  So.  Dearborn  St. 

Dept.  803A,  Chicago,  III. 


or  a 

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*i/-v»T"|  T|"l     t)  F  A  r^FI?  •    When  you  finish  reading  this  magazine  pli.ce  a  1  cent  stamp  on  this  notice,  hand  same  to  any  postal  employee  and  it  will 

^{\J  I  l\,L,     1  \f    IYLAL/EiIV.    placed  in  the  hands  of  our  soldiers  or  sailors  at  the  front.   No  wrapping — no  address. — A.  S.  BURLESON,  Postmaster -Gene 

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ELECTRICAL   NEWS  ILLUSTRATED 


SEEING  WIRELESS 
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PAGE  44  2 


LARGEST  CIRCULATION  OF  ANY  ELECTRICAL  PUBLICATION 


I  Tell  You 
You  Can! 


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Be  a  success  and  command  big  pay.   You  can 

easily  do  it  if  you  will  only  prepare  yourself!  Why 
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Electricians  are  always  in  demand  at  big  pay?  When 
employers  are  searching  for  $3,000  and  $10,000  electrical 
men,  while  this  country  is  crowded  with  poorly-paid 
men  who  could  easily  qualify  for  these  positions ! 


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ELECTRICIAN 


If  you  have  a  common  school  education  you  can  easily  qualify  at  home  by  my  new 
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Course,  while  complete  and  absolutely  scientific,  explains  everything  so  clearly  that  any  one  can 
understand  it  and  do  the  work.  But  this  Course  is  designed  to  give  you  a  real  Electrical  education,  to 
help  men  become  bigger,  better  men — men  who  can  command  big  pay. 

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isfaction or  every  dollar  of  your  money  refunded.  I  can  make  such  a  guarantee  because 

I  know  my  Course  and  what  it  does  for  my  students.  Send  for  free  illustrated  book  telling  all  about  it. 
PART  OF  YOUR  SPARE  TIME  devoted  to  this  interesting  work  is  all  that  is  needed.  You  will  find 
it  most  fascinating,  and  in  a  short  time  your  earning  power  will  be  greatly  increased. 

f  $1722  Electrical  Outfit  Free: 

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stress  \  Dept*  42  CHICAGO,  ILL. 

Tozvn  State  ^^C^^^^^^^ 


November,  1917 


THE   ELECTRICAL  EXPERIMENTER 


433 


EXPERIMENTERS! 


\m 


The  "Electro"  Codophone 

(Patents  Pending) 

Now  that  we  are  for  the  time  being,  deprived  of  using  our 
Radio  outfits,  it  behooves  us  as  good  Americans  to  become 
proficient  in  learning  the  Wireless  as  well  as  Telegraph 
Codes.  Operators  who  know  the  Code  are,  arid  will  be,  in 
ever  rising  demand.  The  Army  and  Navy  need  thousands 
of  operators  right  now. 

So  far  the  Government  has  not  been  able  to  obtain  any 
way  near  all  the  operators  it  requires.  Not  alone  does  the 
Federal  Government  call  for  thousands  and  thousands  of 
operators  for  the  army  and  navy,  but  nearly  all  of  our  many 
states  require  operators  for  the 
militia.  Here  is  the  great  opportun- 
ity of  a  life  time  for  you. ' 

Would  you  rather  fight  in  the 
trenches,  or  punch  the  key  behind 
the  lines?  Either  way  you  benefit 
your  country.  Which  do  you  prefer? 
And  it  is  SO  easy  to  become  an  oper- 
ator. You  do  not  necessarily  require 
a  teacher,  nor  do  you  have  to  go  to 
a  school  to  learn.  30  days  of  intel- 
ligent study  will  make  you  proficient. 
Can  you  qualify  NOW?  Are  you 
proficient?  Can  you  send  and  receive 
when  your  country  calls  you?  ' 

THE  "ELECTRO"  CODOPHONE 

(Patents  Pending) 
which  we  present  herewith  is  the 
outcome  of  several  months  of  intense 
study  and  experimentation  of  our 
Mr.  H.  Gernsback.  It  supersedes  our 
former  Radiotone  Codegraph,  which 
comprised  a  Radiotone  silent  Buzzer, 
a  loud  talking  telephone  receiver  and 
a  key.  As  in  all  of  his  work  Mr.  Gernsback  strives  for  simplicity.  So 
he  combined  the  three  above  mentioned  instruments  with  one  stroke  into 
ONE  single  instrument.  He  combined  the  Radiotone  Buzzer  and  the  loud 
talking  receiver  into  a  single  unit,  not  only  mechanically,  but  electrically 
as  well.  This  involves  an  entirely  new  principle,  never  before  attempted, 
and  on  which  basic  patents  are  now  pending. 

What  this  remarkable  instrument  is  and  does. 
The  "Electro"  Codophone  is  positively  the  only  instrument  made  that 
will  imitate  a  500  cycle  note  exactly  as  heard  in  a  Wireless  receiver,  so 


closely  and  so  wonderfully  clear,  that  Radio  operators  gasp  in  astonish- 
ment when  they  first  hear  it.  And  you  need  no  receivers  over  the  ears  to 
hear  the  imitation  singing  spark,  which  sounds  for  all  the  world  like  a 
high-pitched  distant  powerful  Radio  Station.  No,  the  loud-talking  receiver 
equipped  with  a  horn,  talks  so  loud  that  you  can  hear  the  sound  all  over 
the  room,  even  if  there  is  a  lot  of  other  noise. 

THAT'S  NOT  ALL.  By  lessening  or  tightening  the  receiver  cap,  a  tone 
from  the  lowest,  softest  quality,  up  to  the  loudest  and  highest  screaming 
sound  can  be  had  in  a  few  seconds. 

FURTHERMORE,  this  jack-of-all-trades  marvel,  can  be  changed  in- 
stantly into  our  famous  silent  Radiotone  test  buzzer,  simply  by  replacing 
the  metal  diaphragm  with  a  felt  disc,  which  we  furnish  with  every  instru- 
ment. 

FOR  INTERCOMMUNICATION.  Using  two  dry  cells  for  each  instru- 
ment, two  Codophones  when  connected  with  one  wire  and  return  ground, 
can  be  used  for  intercommunication  between  two  houses  one-half  mile 
apart.  Any  one  station  can  call  the  other,  no  switches,  no  other  appliances 
required.    No  call  bell  either,  the  loud-talking  phone  takes  care  of  this. 

AS  AN  ARMY  TYPE  BUZZER.  Last,  but  not  least,  two  Codophones 
with  two  75  ohm  receivers  can  be  used  to  converse  over  miles  of  fine  (No. 

36  B  &  S  Wire),  so  fine  that  no  one 
can  see  the  wire.  Or  you  can  use  a 
long  metallic  fence  and  the  ground, 
or  you  can  communicate  over  your 
110  volt  line  up  to  several  miles,  us- 
ing no  wires,  only  the  ground. 

Full  directions  how  to  do  all  this 
furnished  with  each  instrument. 

One  outfit  alone  replaces  the  old- 
fashioned  learner's  telegraph  set, 
consisting  of  key  and  sounder,  which 
is  all  right  to  learn  the  telegraph 
code  but  not  the  wireless  codes. 

The  "Electro"  Codophone  is  a 
handsome,  well  made  instrument, 
fool  proof,  and  built  for  hard  work. 
Contacts  are  of  hard  silver  Vs  inch 
in  diameter,  that  will  outlast  the  in- 
strument. Housing  is  of  metal 
throughout,  horn  and  key  lever 
nickel  plated  and  buffed.  Three 
new  style  metal  binding  posts  are 
furnished. 

There  is  also  a  neat  code  chart  and 
full  directions  enabling  any  intelli- 
gent young  man  or  girl  to  learn  the  codes  within  30  days,  practising  one- 
half  hour  a  day. 

Sizes:   6%    x  3  X  2%".     Shipping  weight,   4  lbs. 
The  "Electro"  Codophone  as  described,  complete 

Money  refunded  if  instrument  is  not  as  represented  or  does  not  come  up 
fullv  to  expectation. 

There  will  be  an  enormous  demand  for  this  new  marvel — place  your 
order  now.  All  orders  filled  in  rotation.  Better  order  two  instruments 
today. 


$1.35 


The  "Electro"  Radiotone 

HIGH    FREQUENCY   SILENT   TEST  BUZZER 

The  RADIOTONE  is  NOT  a  mere  test  buzzer, 
it  is  infinitely  more.  Mr.  H.  Gernsback  who  de- 
signed this  instrument  labored  incessantly  to 
produce  an  instrument  which  would  imitate  the 
sound  of  a  high  power  Wireless  station  as  heard 
in  a  set  of  phones.  This  actually  has  been 
achieved  in  the  RADIOTONE.  This  instrument 
gives  a  wonderful  high  pitched  MUSICAL  NOTE 
In  the  receivers,  impossible  to  obtain  with  the 
ordinary  test  buzzer.  The  RADIOTONE  is  built 
along  entirely  new  lines;  it  is  NOT  an  ordinary 
buzzer,  reconstructed  in  some  manner.  The 
RADIOTONE  has  a  single  fine  steel  reed  vibrat- 
ing at  a  remarkably  high  speed,  adjusted  to  its 
most  efficient  frequency  at  the  factory.  Hard 
silver  contacts  are  used  to  make  the  instrument 
last  practically  forever. 


Yes,  the  RADIOTONE  is  SILENT.  In  fact, 
it  is  so  silent  that  you  must  place  your  ear  on 
top  of  it  to  hear  its  beautiful  musical  note. 

You  will  be  astounded  at  the  wonderfully  clear, 
500  cycle  note,  sounding  sharply  in  your  re- 
ceivers, when  operated  on  one  dry  cell.  To  learn 
the  codes,  there  is  absolutely  nothing  like  it. 
With  the  radiotone.  a  key  and  one  dry  cell  and 
ANY  telephone,  a  fine  learner's  set  is  had.  Two 
or  more  such  sets  in  series  will  afford  no  end  of 
pleasure  for  intercommunication  work.  Particu- 
larly now  that  we  cannot  use  our  Wireless  sets, 
the  Radiotone  is  already  in  wonderful  demand. 
All  the  interesting  things  as  described  with  our 
CODOPHONE  (see  our  ad  above),  can  be  per- 
formed with  the  Radiotone,  a  key,  a  dry  cell 
and  a  phone. 

Radiotone 


described  each 

IMMEDIATE  SHIPMENTS 


$.90 


No.  HK  1800 


LABORATORY  OUTFIT! 


We  have  spent  considerable  time  to  com- 
bine just  such  a  practical  outfit  and  pre- 
sent it  herewith  to  our  friends. 

The  outfit  is  complete  as  per  illustration 
and  consists  of: 

1  Stand,  made  of  well  quartered  oak, 
varnished  three  times,  so  as  to  be  acid  proof 
and  grooved  on  top  and  bottom,  so  that  it 
will  not  warp  in  getting  wet.  Size  5;i4 
inches  high  by  11 V2  inches  long. 

1  Glass  Spirit  Lamp.  Size  ?,y2  inches  by 
2  inches.  Uses  wood  alcohol  and  is  in- 
valuable to  the  experimenter.  Besides  be- 
ing used  to  heat  test-tubes  contents  as  per 
illustration,  it  can  be  used  to  bend  glass 
rods  and  tubings,  to  solder  wire.  etc. 

1  Glass  Filter  Funnel.  This  funnel  is 
made  of  heavy  glass  that  will  not  break 
easily.  It  fits  accurately  in  the  hole  on  top 
of  the  Filter  stand  and  is  provided  with  a 
thick  rim  on  the  outlet,  so  that  a  rubber 
hose  can  be  attached  to  it,  without  slipping 
off. 

1  Glass  Rod,  to  be  used  in  stirring  and 
mixing. 

10  Test  Tubes,  made  from  the  best  im- 
ported glass.  A  new  feature  of  some  of 
the  test  tubes  is  that  they  have  a  flat  bot- 
tom and  therefore  can  be  placed  on  any 
table  if  desired,  needing  no  special  stand. 

1  Roll  of  Copper  Clad  Steel  Wire.  This 
wire  is  to  be  used  to  make  a  number  of  use- 
ful   articles   as   shown   in    the  *  illustration. 


such  as  test-tube  holders,  tripods  to  support 
retorts,  etc.  We  furnish  a  blue  print  with 
the  outfit,  showing  how  to  make  all  these 
wire  articles. 

Now  this  whole  outfit  as  described  CI  9C 
costs  you  only  .    «pi.£«J 

'Postage  extra.    Shipping  weight,  4  lbs. 
Order  one  today,  even  if  you  don't  need 
it  now. 

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is  waiting  for  you.  Positively  the  most  com- 
plete Wireless  and  electrical  catalog  in  Mint 
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THE  ELECTRO  IMPORTING  CO. 
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434 


THE  ELECTRICAL  EXPERIMENTER 


November,  1917 


Columbia  Electric 
Grafonola  225  E 
Price  $225. 


Cabinet  of  mahogany,  satin 
walnut,  or  quartered  oak  in 
all  finishes,  measuring 
inches  high  on  castors,  and 
22J/2  x  24  inches.  All  ex- 
posed metal  parts  heavily 
plated  in  18  karat  gold. 
Ample  record  storage  room. 


Electric 
Columbia  Graf  onolas 

at  $125,  $135,  $175,  and  $225 

THE  Columbia  Electric  Grafonola  125  E  is  equipped  with  an  electric 
motor  that  is  a  marvel  of  accuracy  and  precision.  It  operates  per- 
fectly on  any  standard  current,  whether  direct  or  alternating,  and  can 
be  attached  to  any  socket — Price  $125.  Same  model  equipped  with 
Columbia  Individual  Record  Ejector — Price  $135. 

The  Columbia  Electric  Grafonola  175  E  is  designed  to  give  satisfaction  under  any 
and  all  conditions.  It  provides  the  highest  possible  tone-quality  and  every  refine- 
ment of  mechanism,  form  and  finish  to  correspond.    Price  $175. 

With  its  electrical  and  mechanical  improvements,  the  Columbia  Electric  Grafonola 
225  E  is  an  instrument  embodying  the  most  perfect  reproducing  qualities  and  refine- 
ment and  one  that  will  be  as  well  a  harmonious  part  of  the  best  appointed  music 
rooms.  The  motor,  a  marvel  of  silence  and  smoothness,  holds  the  tone  absolutely  true. 
Price  $225. 


You  benefit  by  mentioning  "The  Electrical  Experimenter"  when  writing  to  advertisers. 


ctrieal  Experimenter 


233  FULTON  STREET,  NEW  YORK 

Publisht  by  Experimenter  Publishing  Company,  Inc.  (H.  Gernsback,  President;  S.  Gernsback,  Treasurer;)  233  Fulton  Street,  New  York 


Vol.  V     Whole  No.  55 


NOVEMBER,  1917 


No.  7 


SEEING  WIRELESS  SIGNALS  Front  Cover 

From  a  painting  by  George  Wall 
TELEGRAPH   AND   TELEPHONE   ON    EUROPEAN  BATTLE- 
FIELDS  437 

ELECTRICITY  BEING  USED  TO  HASTEN  CROPS   439 

ARE  CABLE  MESSAGES  SAFE?   440 

LOCATING  UNDERGROUND  ORES  BY  ELECTRICITY   441 

SEEING  WIRELESS  SIGNALS  (Front  Cover  Article)   442 

MICROPHONES  IN  TRENCH  WARFARE  By  H.  Gernsback  443 

"MOVIES"  SHOW  WOMEN'S  PLACE  IN  WAR   444 

HOW  BIG  ELECTRIC  MEN  WORK  By  George  Holmes  445 

SOMETHING  NEW  IN  MICROPHONES   446 

HISTORIC  ELECTRIC  APPARATUS  

By  H.  Winfield  Secor,  E.E.  448 

THE  MARVELS  OF  RADIO  ACTIVITY.    PART  III  

By  Jerome  S.  Marcus,  B.  SC.  (Ch.  E.)  450 
177,000   C.    P.    MERCURY   VAPOR   LAMPS   LIGHT  "MOVIE" 

STUDIO    452 

BUCKING  THE  "LODGE  GOAT"— ELECTRICITY  .. .-   453 

THE  CAUSE  AND  NATURE  OF  MAGNETIC  CURRENTS  

By  F.  F.  Mace  454 

WELDING  WITH  THE  ELECTRIC  ARC   456 

ACTION  AT  A   DISTANCE  AS   EXHIBITED   IN  SELENIUM 

CRYSTALS  By  Prof.  F.  C.  Brown,  Ph.  D,  459 


EXPERIMENTAL  PHYSICS— LESSON  9  

By  John  J.  Furia,  A.B.,  M.A.  460 
RADIO  LEAGUE  OF  AMERICA— NEWS  FROM  COMM.  D.  W. 

TODD,  U.S.N.,  AND  THE  "RADIO  ROLL  OF  HONOR"...  461 

BEING  A  NAVAL  WIRELESS  MAN  

By  Howard  S.  Pyle,  U.S.N.  463 
DEVELOPMENT  OF  AIRCRAFT  RADIO  IN  THE  U.  S.  NAVY 

t  By  Benjamin-  F.  Miessner,  Expert  Radio  Aide,  U.S.N.  465 

CONSTRUCTION  OF  A  LABORATORY  VACUUM  PUMP  

By  Raymond  Francis  Yates  467 

AN  AUTOMATIC  STORAGE  BATTERY  CHARGER...  

By  Lewis  Scriven  468 
CHEMICAL  ACTION  OF   STORAGE   BATTERIES  (Conclusion) 

By  Albert  W.  Wilsdon  473 

HOW-TO-MAKE-IT   DEPT. — Prize   Contest   474 

WRINKLES,  RECIPES  AND  FORMULAS  

Edited  by  S.  Gernsback  476 

EXPERIMENTAL   CHEMISTRY— 18th  Lesson  

By  Albert  W.  Wilsdon  477 

"ELECTRICAL   LABORATORY"— Prize   Contest   478 

AN  EXCEPTIONAL  EXPERIMENTAL  LABORATORY  

By  George  Holmes  and  Albert  W.  Wilsdon  479 
OUESTION    BOX   482 


J] 


Imagination  Versus  Facts 


S  is  well  known,  the  Electrical  Exper- 
imenter ever  since  its  inception  has  been 
heavily  indebted  to  Dame  Imagination. 
Imagination  makes  the  world  go  round — 
imagination  means  progress. 

Sometimes  we  have  been  lauded  for 
exploiting  imagination,  more  often  we  have  been  crit- 
icised severely.  Harsh  things  have  not  infrequently 
been  said  about  our  wholly  imaginary  writings  and  es- 
says, and  we  will  probably  be  thus  criticised  indefinitely. 

We  certainly  lay  no  claim  to  the  fact  that  our  imag- 
inary writings  always  turn  out  to  be  correct  in  the  end, 
but  we  point  with  pardonable  pride  to  the  fact,  that 
often  our  supposedly  "pipe  dreams"  come  true.  Here 
is  a  recent,  as  well  as  concrete  example : 

In  the  early  summer  of  1915  while  the  German  owners 
of  the  Sayville  Wireless  Station  were  still  operating 
the  latter  unmolested,  it  occurred  to  us  that  "all  was 
not  well"  with  that  particular  station.  Certain  prominent 
amateurs  mentioned  the  fact  that  "irregular"  messages 
were  being  sent  over  Sayville.  Then  early  in  July  1915 
our  Government  took  over  the  Sayville  Radio  Station, 
but  the  German  owners  still  remained  on  the  grounds. 

This  partly  prompted  our  editorial  entitled  '  Sayville" 
in  our  August  1915  issue,  in  which  we  desired  to  convey 
the  idea  that  even  with  our  Government  officials  in 
charge,  unneutral  messages  could  still  be  sent  out  over 
Sayville. 

This  editorial  at  once  brought  a  violent  letter  of 
protest  from  Dr.  K.  G.  Frank,  the  then  executive  head 
of  the  Sayville  Radio  Station.  Dr.  Frank  strenuously 
denied  that  Sayville  was  sending  out  unneutral  mes- 
sages, and  closed  his  letter  by  strongly  abusing  this 
journal.  In  our  reply  (see  our  October  1915  issue  for 
entire  correspondence)  we  firmly  voiced  our  former 
opinion  that  Sayville  was  indeed  sending  out  such  un- 
neutral messages,  and  we  then  cited  facts.  Before 
proceeding  we  might  mention  that  Dr.  Frank  has  since 
been  interned  by  this  Government  for  the  duration  of 
the  war. 

But  that  unneutral  messages  actually  were  being  sent 
out  as  late  as  1916  and  perhaps  later  came  as  a  surprise 
even  to  us.  Remember  our  own  Government  operators 
were  in  charge,  but  the  wily  Germans  did  just  what  we 


suspected  them  of  having  been  doing  right  straight  along. 

We  give  below  in  one  column  an  extract  from  our 
August  1915  editorial — an  admittedly  wholly  imaginary 
case; — in  the  other  column  are  shown  the  actual  facts 
as  recently  disclosed  by  our  State  Department.  This 
latter  radio  message  was  sent  in  April  1916  over  Say- 
ville, and  was  in  connection  with  the  famous  Roger 
Casement  affair.  That  the  imaginary  as  well  as  the 
real  message  should  both  be  addrest  to  bankers  is 
rather  startling,  to  say  the  least. 

EXTRACT  FROM  OUR  EDI-      German  submarine  commander 
TORIAL,   AUGUST   1915.         is  enabled  to  change  his  course 
"Let    us    imagine    the    follow-       in  order  to   successfully  hunt 
ing:    A  German  spy  is  located      his  quarry. 

This  is  only  one  of  the  ways 
how  the  wireless  stations  at 
Sayville  and  Tuckerton  can  be 
used  successfully  to  violate  our 
neutrality;  there  are  undoubt- 
edly  scores  more." 

DISCLOSURE      BY  OUR 
STATE  DEPARTMENT, 

SEPTEMBER  1917. 
"Along  the  same  line  is  a 
code  message  by  wireless  to 
Banker  Max  Moebius,  Ober- 
wallstrasse,  Berlin,  which  is 
interesting  chiefly  as  showing 
the  code  method  of  important 
communications  practised  by 
the  German  Official  plotters  in 
this  country.  The  code  trans- 
lation was  found  with  the  copy 
of  the  message  among  von 
Igel's  papers.  The  original  is 
a  German  dispatch  which  be- 
ing translated  into  English, 
sounds  like  an  innocent  busi- 
ness transaction  viz.: 

National  Get-mania  Insur- 
ance Contract  certainly  prom- 
ised. Executor  is  evidently 
satisfied  with  proposition.  Nec- 
essary steps  have  been  taken. 

Henry  Ncuinan. 
Not  so  innocent  and  harm- 
less as  it  looks,  for  what  the 
message  really  means  is  this: 

"Irish  agree  to  proposition. 
The  necessary  steps  have  been 
taken 


on  the  ocean  liner  Adriatic 
headed  for  Liverpool.  When 
two  days  out  the  spy  learns 
that  the  ship,  on  account  of 
submarine  danger,  will  not 
dock  at  Liverpool  but  at 
Greenock  (Scotland)  instead. 
He  then  sends  a  wireless  to  a 
stockbroker  in  New  York  as 
follows : 
H.  P.  Frye  &  Co., 

Wall  Street,  New  York. 
Sell  at  once  2,000  shares  U. 
S.  Steel  at  58. 

John  Miller. 
When    Frye   &    Co.  receive 
the  message  they  consult  their 
code    book    and    find    that  it 
reads  thus: 

"Adriatic  will  dock  at 
Greenock." 

Frye  &  Co.,  then  sends  this 
Radio  via  Sayville: 

f.    S.  Schneider  &  Co., 

Fried richstrasse,  Berlin. 
"Cannot  dispose  2,000  shares 
shares  V.  S.  Steel  at  58. 

Are  bid  55 Advise." 

Frye  &  Co. 
The  message  is  promptly  re- 
ceived by  the  German  com- 
mander of  submarine  U-69  not 
far  from  the  south  coast  of 
Ireland. 

He  reads  the  harmless  mes- 
sage thus: 

"Adriatic      will      dock  at 
Greenock   next  Tuesday." 
With    this    intelligence  the 


Truth,  indeed,  is  stranger  than  fiction,  and  imagina 
tion  is  often  improved  upon.  H.  Gernsback. 


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THE  ELECTRICAL  EXPERIMENTER 


November,  1917 


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THE  ELECTRICAL 
EXPERIMENTER 


H.  GERN5B&CK  editpr 

H.  W.  5ECPR  d550ClftTE  EDITOR 


Vol.  V.   Whole  No.  55 


November,  1917 


Number  7 


~7?  73 — 


Telegraph  and  Telephone  on  European  Battlefields 


IN  no  war  in  the  past  have  the  electric 
signaling  systems  covered  so  many 
square  miles  or  such  a  great  diversity 
of  requirements.  The  commanding 
general  wants  to  know  how  a 
certain  division  is  progressing;  an  artil- 
lery   captain    wants    to    ascertain  just 


adventure,  action — all  of  these  come  to  the 
Signal  Corps  man  in  the  pursuit  of  his 
duties  more  than  ever  before.  To-day  he 
may  install  a  telephone  switchboard  in  a 
cheerful  little  town  near  grand  head- 
quarters, situated  a  dozen  miles  back  of 
the  battle-front.     To-morrow  he  may  be 


came"aTcmg  and  was  pleased  to  learn  that 
all  of  the  circuits  had  been  tested  out 
without  losing  a  man.  The  same  captain 
was  grieved  to  hear  the  next  day  that  this 
brave  lineman,  his  work  done,  had  been 
picked  out  of  a  pole-top  by  a  stray  shell. 
At  the  beginning  of  the  war  there  were 


A  Birdseye  View  of  a  Modern  Battle-field  With  the  Various  Telegraph  and  Telephone  Lines  Linking  the  Advanced  Trenches  With 
the  Artillery  in  the  Rear,  Also  Enabling  the   Post  Commanders  to  Communicate  at  Once  With   Any  Section   of  Trench    Line  for 
Combined   Assaults.     Note   the    Large    Number   of   Shell    Craters,    Reproduced  from  Actual  Photograph. 


where  his  shells  are  dropping ;  these  and  a 
million  other  facts  must  be  transmitted 
every  hour  of  the  day  along  the  hundreds 
of  miles  of  battle-front.  And  it  is  really 
marvelous  how  the  army  signal  corps  have 
perfected  their  frail  looking  wires  and 
instruments,  so  that  they  will  work  under 
the  most  unfavorable  conditions.  Romance, 


stringing  wires  thru  a  shell-swept  forest. 
One  case  which  is  on  record  will  serve  to 
show  the  lottery-like  chance  these  men 
take.  An  English  military  lineman  had 
been  busy  for  several  weeks  in  a  district 
near  the  Aisne  battle-front.  He  had  about 
completed  straightening  out  a  perfect 
jungle  of  wires  and  circuits.    Mis  captain 


certain  dangers  connected  with  telephonic 
communication,  for  our  foes  were  not  slow 
to  try  to  catch  our  communications,  and 
their  engineers  were  soon  busily  engaged 
establishing  delicate  microphones  near  our 
telephone  lines,  so  as  to  intercept  messages 
and  learn  of  our  projected  actions,  says 
Isidore  Recoulier,  commander  of  a  section 


437 


438 


THE  ELECTRICAL  EXPERIMENTER 


November,  1917 


of  French  sapper  telegraphers.  We  soon 
learned  of  this  and  have  now  apparatus  by 
which  any  such  "cutins"  or  listening  is 
practically  impossible,  for  great  advances 
have  been  made  in  the  arts  of  telephony 
since  the  beginning  of  the  war. 

We  have  had  to  develop  a  system  by 
which  the  telephone  wires  used  by  the  artil- 
lery and  infantry  could  be  instantly  distin- 
guished from  one  another,  so  that  we  might 
not  mix  up  the  lines,  for  while  they  co- 


which  an  officer  receives  all  useful  informa- 
tion, making  it  possible  for  him  to  follow 
the  least  movement  of  his  troops.  Near 
this  officer  another  insures  his  connection 
with  the  aides  of  the  generalissimo,  especial- 
ly charged  with  conveying  orders  from  the 
chief  of  the  army.  These  orders  are  called 
"Directives." 


these  groups  with  the  wireless  headquarters, 
which  are  in  direct  connection  with  observ- 
ers on  aeroplanes  and  captive  balloons,  as 
well  as  with  posts  of  observation  on  the 
ground. 

It  must  not  be  forgotten  that  the  artil- 
lery works  by  concentration  of  fire.  The 
artillery  must  prepare  the  way  by  battering 
down  forts  or  trenches  for  the  advance  of 
the  infantry — so  both  must  be  kept  in  close 
touch.    The  aviators  signal  how  and  where 


operate,  the  systems  are  absolutely  separate. 

The  ordinary  telephone  is  easily  establisht, 
running  from  the  point  of  contact  with  the 
enemy  to  the  chief  of  that  sector,  and  from 
the  sector  itself  to  the  commander.  When 
these  wires  were  so  simply  laid  as  at  first 
it  was  easy  for  the  enemy  to  "listen  in," 
but  now  the  current  is  returned  by  special 
conductors,  and  the  use  of  spy  microphones 
is  almost  impossible.  The  artillery  has  its 
telephone  system,  independent  of  the  other 
lines,  but  connecting  with  the  headquarters 
of  attacking  and  defensive  troops.  A  line 
is  run  on  the  front,  in  any  way  that  the 
ground  will  permit,  and  kept  in  order  at 
any  risk.  Often  when  the  bombardment  is 
heaviest,  one  of  these  wires  is  broken  and 
must  be  repaired,  while  shot  and  shell  burst 
among  the  engineers.  When  an  attack  is 
in  progress  the  telephone  engineers  follow 
the  line  closely,  installing  new  stations  at 
the  first  possible  moment,  so  as  to  keep  in 
touch  with  the  rear  and  the  centre  of  com- 
mand. If  driven  back,  this  corps  has  to 
pick  up  all  material  so  that  it  will  not  fall 
into  the  hands  of  the  enemy. 

After  the  cannon,  whose  fire  has  been 
directed  by  aviators  and  captive  balloons 
via  radio,  have  smashed  the  trenches  of  the 
enemy,  and  they  extend  their  fire,  the  in- 
fantry attack  begins  and,  bayonets  couched, 
the  men  advance.  The  various  units  follow 
each  other  in  obedience  to  orders  from  their 
leaders.  These  orders  are  long  since  decided 
upon,  and  in  the  midst  of  this  tumult  all  is 
directed  by  a  general  plan.  Meanwhile, 
further  to  the  rear,  the  generalissimo,  the 
general  commanders,  the  chiefs  of  the  army 
corps,  of  divisions  and  brigades,  with  detail 
maps  spread  out  before  them,  follow  the 
movements  and  give  their  orders.  All  of 
this  has  to  be  done  along  the  wires  of  the 
telephone. 

The  generalissimo  is  stationed  in  a  house 
where  many  lines  meet,  so  that  he  can  be 
in  constant  communication  with  all  the  rear 
and  the  advance.  Every  chief  of  service  in 
turn,  as  well  as  every  commander  of  a  unit, 
of  one  or  more  lines,  is  ready  with  a  report, 
awaiting  orders.  The  development  of  the 
telephonic  communication  between  head- 
quarters and  all  parts  of  the  forces  has 
been  so  perfected  that  it  works  without 
delay.  Each  army  is  connected  with  Gen- 
eral Headquarters  by  a  line  at  the  end  of 


Photos  from  Central  News  Photo  Service 


Left. — A  Photo  From  the  Egyptian  Battle- 
Front.    Advanced  English  Artilleryman  Tele- 
phoning   Warning   of   Enemy    Aircraft  Ap- 
proaching.    Note  the  Camel. 


Center. — A  French  Officer  of  Engineers  In  a 
Mine  Gallery,  with  Newly  Invented  Micro- 
phone, Detecting  the  Sounds  of  German 
Counter  Mining  Operations.  Men  Who  Do 
This  Work  Are  Called  "Listeners."  Listen- 
ing Is  a  Very  Delicate  Operation.  It  Consists 
of  Detecting  the  Direction,  Height,  and  Dis- 
tance of  the  Sounds  Heard.  To  Obtain 
Greater  Clearness,  Drums  Are  Used  as  Well 
as  Special  Microphones.  As  Soon  as  a  Pro- 
longed Silence  on  the  Part  of  the  Enemy  Is 
Noticed  After  a  Period  of  Rather  Hard  Work, 
the  Conclusion  Is  That  a  Chamber  Is  Being 
Loaded,  and  at  Once  You  Charge  Your  Own 
Mine.  The  Loading  of  the  Mine-Chamber  Is 
Followed  by  the  Operations  of  Connecting 
the  Fuse  and  Tamping.  The  Latter  Con- 
sists of  Blocking  Up  the  Mine-Chamber  with 
Bags  of  Earth  or  Sand,  so  as  to  Direct  the 
Force  of  the  Explosion  Towards  the  Enemy. 


Right. — A  Central  Telephone  Station  in  the 
French  Trenches  at  the  Aisne. 


In  its  turn  the  general  quarters  of  an 
army  is  connected  with  general  headquarters 
from  which  it  receives  orders  and  to  which 
reports  of  each  phase  of  action  must  speed. 
Moreover,  it  is  in  close  communication  with 
neighboring  armies  as  well  as  with  the  army 
corps  under  its  direction. 

Each  army  corps  is  itself  connected  with 
the  army  of  which  it  is  a  part,  and  as  fol- 
lows :  From  the  army  corps  to  division,  to 
the  brigade,  to  regiments,  to  the  trenches 
as  far  as  the  first  line  and  outposts. 

This  primary  circuit  allows  the  sending 
of  orders  and  knowledge  as  to  how  they  are 
carried  out. 

The  telephonic  circuits  of  the  artillery 
are  much  more  complicated.  It  plays  the 
same  part  as  the  former  for  batteries  and 
groups ;  but  more  than  this,  it  serves  for 
reporting  on  location  of  objectives  and 
directing  the  fire.  It  has  to  insure  the  co- 
operation of  the  various  groups  of  artillery 
with  one  another,  and  the  connection  of 


the  fire  should  be  directed.  The  telephone, 
telegraph  and  wireless  all  play  their  part. 

Whether  in  the  trenches  or  in  defensive 
operations  the  telephone  has  a  great  im- 
mediate value,  and  even  in  advance  move- 
ments, whenever  a  halt  takes  place  the  very 
first  duty  of  the  engineering  corps  (tele- 
graphic division),  is  to  establish  com- 
munication by  telephone  with  the  rear.  The 
military  telephone  is  quite  different  from 
the  regular  machine.  It  consists  in  its 
simplest  form  of  a  "combination"  (micro- 
phone and  telephonic  ear-piece,  joined  by  a 
hard  rubber  handle,  etc),  the  branch-box, 
induction  coil  box  and  battery  for  produc- 
ing the  current.  In  setting  the  wires  care 
is  taken  to  prevent  "grounding,"  isolating 
the  wires  as  carefully  as  possible.  Usually 
the  line  is  laid  by  four  men ;  an  unroller  (of 
the  wire),  an  assistant,  a  mounter  and  as- 
sistant. The  unroller  carries  the  wire  on 
a  bobbin  in  his  left  hand,  playing  the  wire 
out  slowly.  His  assistant  keeps  the  wire 
straight.  The  mounter  attaches  the  wire  to 
the  point  of  departure,  his  assistant  hands 
him  the  wire  as  needed,  who  lays  it  upon  its 
supports  as  he  advances.  When  he  reaches 
the  end  of  a  piece  of  cable  he  tests  his  con- 
nection carefully  to  the  point  of  departure. 
He  marks  by  a  pebble  or  bit  of  paper  the 
point  where  he  has  connected  each  500  yard 
cable,  in  case  of  breaks.  He  locates  his  sta- 
tions in  the  safest  possible  places,  out  of 
view  of  the  enemy,  or  protected  as  much 
as  possible.  If  an  advanced  position  must 
be  abandoned,  the  corps  in  charge  of  the 
laying  work  takes  up  the  wires  as  rapidly 
as  possible,  removing  all  memoranda  from 
the  station,  and  beat  a  retreat  with  the  line. 

Wireless  has  proved  of  great  value  for 
aviators  to  convey  their  information  to  their 
forces,  and  only  within  the  last  year  and  a 
half  has  the  method  of  communication  been 
perfected.  For  obvious  reasons  the  con- 
struction of  the  antennae  and  other  parts 
cannot  be  described.  Suffice  it  to  say  that 
methods  of  communication  between  the  aero- 
planes and  the  ground  have  been  devised, 
and  they  are  of  such  kind  that  the  enemy 
cannot  intercept  the  messages.  The  captive 
balloons  use  a  telephone  wire  which  unrolls 
as  the  balloon  ascends.  Batteries  alone  are 
possible  in  campaign  telephony,  and  special 
batteries  have  been  devised  which  are  both 
light  and  powerful. 


November,  1917 


THE  ELECTRICAL  EXPERIMENTER 


439 


Electricity  Being  Used  to  Hasten  Crops 


EXPERIMENTS  on  a  large  scale 
with  the  use  of  electricity  to  stim- 
ulate the  growing  of  crops  are 
among  the  English  government's 
latest  efforts  to  increase  the  coun- 
try's home  food  production.  The  depart- 
ment of  agriculture  has  taken  over  a  large 
area  near  Hereford,  where  installations 
have  already  been  set  up  for  the  use  of 
ionized  agricultural  experts  under  Prof.  W. 
H.  Blackman  of  the  Imperial  College  of 
Science  and  Technology  who  will  supervise 
the  experiments. 

In  the  Hereford  experiment  high  tension 
alternating  current  is  to  be  used.  Spring 
wheat,  barley,  oats  and  clover  will  be  dealt 
with,  and  fertilizers  of  various  types  will 


about  $300,    which  is  not  so  very  high. 

The  present  method  of  overhead  dis- 
charge from  wires  stretched  over  the  crops 
was  introduced  into  England  twenty  years 
ago  by  Professor  Lemstrom  of  Helsingfors, 
whose  book,  "Electricity  in  Agriculture  and 
Horticulture,"  anyone  interested  in  the  sub- 
ject should  consult.  The  method  was  modi- 
fied by  Mr.  J.  E.  Newman,  in  conjunction 
with  Sir  Oliver  Lodge.  These  and  others 
formed  themselves  into  the  Agricultural 
Electric  Discharge  Company,  which  dis- 
posed of  a  large  number  of  installations 
both  in  England  and  abroad. 

Very  contradictory  results  were  obtained 
by  the  various  users  of  the  Lodge-Newman 
apparatus,  and  the  subject  lost  much  pres- 


Roberts,    near    Carnarvon    in  Wales. 

The  engineers  of  the  Carnarvon  plant 
are  convinced  of  several  important  features 
which  have  not  been  previously  noted. 
They  are  emphatically  of  opinion  that  the 
ionization  of  atmosphere  is  but  of  sec- 
ondary importance,  though  attention  is  be- 
ing particularly  paid  to  the  influence  of 
prevailing  winds  to  widen  the  area  of  in- 
fluence. They  maintain  the  main  effect  of 
the  discharge  is  noticeable  on  the  soil,  and 
that  soils  heavily  manured  are  more  effec- 
tively benefited  by  reason  of  the  latent  hu- 
midity. The  active  result  upon  the  soil  is 
apparently  due  to  the  release  and  nitrifica- 
tion essential  to  the  well-being  of  plant  life. 
The  dark  green  foliage  and  the  building-up 


NIGHT-SCENE  OF  AN    ENGLISH    HIGH   FREQUENCY  PLANT  GROWER. 

In  England,  More  Than  In  the  United  States,  the  Stimulating  Effect  of  a  High  Tension,  High  Frequency  Discharge  on  the  Growth 
of  Plants,  Particularly  Vegetables,  Is  Being  Carefully  and   Extensively  Tested  Out.    Standard  High  Voltage  Electric  Generators  for 

This   Purpose  Are  Available  on   the   English  Market. 


also  be  used   in  these  experiments. 

The  method  adopted  is  to  stretch  over 
the  field  to  be  treated  a  number  of  thin 
wires  on  poles,  something  like  low  tele- 
graph wires,  but  high  enough  for  loaded 
wagons  to  pass  underneath.  The  wires  are 
supported  by  high  tension  insulators  on 
posts  in  long  parallel  spans  thirty  feet 
apart. 

"The  charge  fizzes  off  from  the  wires," 
says  one  account,  "with  a  sound  which  is 
sometimes  audible,  and  with  a  glow  which 
is  visible  in  the  dark.  Anyone  walking 
about  below  the  wires  can  sometimes  feel 
the  effect  on  the  hair  of  the  head,  as  a 
cobweb  on  the  face.  The  electricity  does 
not  act  as  a  fertilizer  but  as  a  substitute 
for  sunlight.  The  current  is  only  used  in 
the  early  morning  and  in  cloudy  weather." 
The  initial  cost  of  the  apparatus  for  twenty- 
four  acres  is  about  $1,500,  and  the  animal 
cost,  including  depreciation  and  labor,  is 


tige.  The  results  of  the  company's  own 
experiments  with  wheat  in  over  a  series 
of  years  were  reported  as  an  increase  vary- 
ing from  0  per  cent  to  39  per  cent.  The 
next  phase  in  the  development  of  electro- 
culture  opened  in  1911.  The  British  Board 
of  Agriculture  gave  a  grant  to  Professor 
Priestley  of  Leeds  for  a  scientific  investi- 
gation of  these  new  methods  and  their 
value.  Professor  Priestley  collaborated  with 
Mr.  I.  Jorgensen,  an  electrical  expert  and 
plant  physiologist,  and  with  Miss  E.  C. 
Dudgeon  of  Dumfries.  In  the  result  it 
appeared  that  many  technical  difficulties 
existed.  At  first  no  favorable  results  were 
obtained,  but  in  the  last  two  years,  with 
improved  methods,  increases  of  SO  per  cent 
over  the  ordinary  crop  have  been  recorded 
with  oats  on  Miss  Dudgeon's  land. 

A  very  complete  installation  has  recently 
been  connected  up  in  the  extensive  veg- 
etable gardens  owned  by  Sir  Thomas  E. 


of  new  tissue  is  evident  proof  of  the  greater 
vigor  and  increased  growth  of  the  plant. 
Furthermore,  confirmation  is  provided  of 
the  fact  that  sunlight  is  detrimental  for  the 
discharge  to  be  in  operation  at  the  same 
time  (more  successful  working  is  obtained 
at  sunrise  and  sunset)  ;  a  time-switch  can 
be  automatically  arranged  to  switch  the  cur- 
rent on  and  off  at  these  times. 

This  fact  also  emphasizes  the  approxi- 
mate degree  of  humidity  necessary  for  the 
success  of  the  discharge,  as  the  amount  of 
dew  or  latent  humidity  prevalent  at  these 
periods  are  more  or  less  helpful.  Whereas, 
in  heavy  rain  the  discharge  is  inclined  to- 
run  to  waste,  owing  to  insulation  troubles. 
It  must  be  borne  in  mind  that  the  intensi- 
fied and  rectified  voltage  of  75,000  volts  to> 
100,000  volts  has  to  be  dealt  with  in  a  very 
different  manner  to  the  ordinary  electric 
light  voltage,  and  the  methods  of  control 
(Continued  on  page  493) 


440 


THE  ELECTRICAL  EXPERIMENTER 


November,  1917 


Are  Cable  Messages  Safe? 


THE  great  activity  of  the  Kaiser's 
sub-sea  fighters  have  led  many  people 
to  ask  the  question — "what  of  our 
ocean  cables  ?"  One  of  the  leading 
cable  experts  in  this  country  recently 
answered  this  question  by  saying — "Well, 
let  the  Huns  cut  the  cables;  what  of  it? 


People  in  general  are  quite  unfamiliar 
with  the  ocean  cable  and  its  maintenance, 
especially  during  war  times.  At  present, 
and  in  fact  since  the  United  States  declared 
war  against  Germany,  the  cable  companies 
have  taken  proper  steps  to  have  all  land 
lines  closely  guarded  night  and  day.  A 


drop  the  cable  ends,  which  it  possibly  had 
picked  up  after  a  long  hunt,  in  its  effort  to 
out-run  the  U-boat.  Altho  not  public 
knowledge,  one  of  the  leading  cable  com- 
panies has  lost  one  of  its  best  cable  repair 
and  supply  ships,  it  having  been  torpedoed 
in  the  Mediterranean.  The  crew  was  saved, 
luckily,  as  the  ship  was  not  far  from  shore. 


Photos  from  Donald  McNicol 

Fig.  1.    What  the  Interior  of  a  Modern  Ocean  Cable  Office  Looks  Like.    This  is  the 
Trans-Atlantic  Cable  Office  at  Penzance,  England,  the  No.  1  London  Wire,  Duplexed, 
and  Creed  Automatic  Cable  Instruments  Being  Shown. 


OBSERVATIONS 
OF  ATMOSPHERIC  ELECTRICITY 
AND  OCEAN  MAGNETIC  WORK. 

A  series  of  volumes  reprinted  from  the 
publications  of  the  Carnegie  Institute, 
Washington  (U.S.A.),  describe  in  detail 
the  work  undertaken  by  the  "Galilee" 
(1907-8)  and  the  "Carnegie"  (1909-1916) 
in  connection  with  electric  and  magnetic 
observations  at  sea.  The  three  volumes 
before  us  deal  respectively  with  ocean  mag- 
netic work  and  atmospheric  electric  ob- 
servations, records  of  which  are  presented 
in  a  very  complete  and  elaborate  way.  The 
accurate  determination  of  the  intensity  of 
the  earth's  magnetic  field  at  sea  naturally 
offers  special  difficulties,  such  as  do  not 
occur  in  a  well-equipt  laboratory  on 
land,  and  magnetic  storms  can  also  be  reck- 
oned with,  altho  their  effect  seems  to  have 
been  relatively  small  and  transient.  In  the 
earlier  researches  on  the  "Galilee"  the  ob- 
server had  also  to  contend  with  the  dif- 
ficulty of  a  magnetic  ship.  The  design  and 
mounting  of  the  various  instruments  are 
described  in  great  detail,  and  this  collec- 
tion of  data  presented  will  no  doubt  con- 
stitute a  valuable  record. 


In  48  hours  the  cable  companies  would  have 
a  fleet  of  repair  boats  on  the  spot  splicing 
the  cables,  suitably  convoyed  by  naval  ves- 
sels and  this  would  hold  good  for  either 
European  or  American  coasts." 

The  accompanying  picture,  Fig.  1,  shows 
an  interior  view  of  the  Trans-Atlantic 
cable  station  at  Penzance,  England.  The 
apparatus  on  one  of  the  circuits  extend- 
ing to  London,  England,  is  shown  on  the 
table,  to  the  right.  The  wire  is  duplexed, 
(i.e.,  two  different  messages  are  sent  over 
the  cable  at  the  same  time),  and  is  operated 
in  the  same  manner  as  the  longer  Trans- 
Atlantic  sections.  In  the  back-ground  is 
shown  a  set  of  "Creed"  automatic  cable 
instruments. 

The  second  picture,  Fig.  2,  shows  one 
corner  of  the  operating  room  of  the  Trans- 
Atlantic  cable  office  at  Penzance,  England. 
The  two  instruments  on  the  right  are 
''Creed"  automatic  transmitters.  As  the 
perforated  paper  tape  passes  thru  the 
transmitters,  it  falls  into  baskets  as  shown. 
Tust  to  the  left  of  the  second  instrument 
from  the  left  of  the  picture,  may  be  seen 
one  of  the  double-lever  hand  keys  used  by 
cable  operators. 

The  maintenance  of  ocean  cables  is  one 
of  the  most  interesting  studies.  A  peculiar 
fact  in  this  direction  is  that  of  the  18  Trans- 
Atlantic  cables  now  in  service  there  are 
always  two  out  of  order;  not  the  same 
two  of  course,  but  two  out  of  the  total 
number.  Thus  the  cable  ships  always  find 
something  to  do,  in  both  winter  and  summer. 

There  are  now  18  ocean  cables  linking 
America  with  Europe.  The  cable  terminals 
are  practically  all  under  military  guard  and 
even  the  officers  of  the  cable  companies  are 
not  allowed  near  the  cable  land  lines  or 
terminal  buildings,  unless  on  special  busi- 
ness and  then  only  when  accompanied  by  a 
military  cniard. 


fleet  of  cable  repair  ships  carrying  expert 
repairmen  and  engineers  are  always  waiting 
to  dart  here  and  there,  as  soon  as  they  re- 
ceive the  news  that  a  cable  has  gone  bad 
or  been  cut.  If  the  cable  ship  has  only 
to  make  repairs  along  the  shore  or  a  short 
distance  out,  no  naval  convoy  is  required. 
However,  if  the  cable  ship  has  to  proceed 
to  sea,  then  a  naval  escort  is  furnished  as 
a  hostile  submarine  would  be  an  unwelcome 
visitor,  besides  causing  the  cable  ship  to 


SUBMARINES  SEE  WITHOUT 
PERISCOPES? 

The  Revista  Maritima  mentions  that  sub- 
marines are  now  being  constructed  with- 
out periscopes  of  the  ordinary  type.  In- 
stead of  the  usual  vertical  tube  arrange- 
ment a  system  of  two  lenses,  one  on  either 
side  of  the  vessel,  is  being  employed.  It 
is  claimed  that  this  device  is  much  less 
visible  from  a  distance,  altho  it  has  the 
drawback  that  the  vessel  must  navigate 
nearer  to  the  surface.  The  device  appears 
to  be  only  in  the  experimental  stage. 


Fig.  2.  This  Picture  Shows  One  Corner  of  the  Operating  Room  of  the  Trans- 
Atlantic  Cable  Office  at  Penzance,  England.  The  Perforated  Paper  Tape  Passes 
Thru   the   Automatic  Transmitters  Which    Send   Out  the    Dots   and    Dashes  Thru 

the  Cables. 


November,  1917 


THE  ELECTRICAL  EXPERIMENTER 


44  i 


Locating  Underground  Ores  by  Electricity 


THE  basic  problem  to  the  mining  in- 
dustry is  the  finding  of  ore  in  pay- 
ing quantities.  This  difficulty  has 
produced"  many  operators  of  the  di- 
vining rod,  and  several  other 
methods  have  been  tried  in  the  effort  to  de- 
termine the  hidden  ore  conditions  under- 
ground and  avoid  the  expense  of  drilling 
or  of  sinking  shafts  in  barren  grounds. 
The  whole  subject  is  of  great  in- 
terest, and  the  possibilities  are  so  vast 
that  no  one  need  be  surprised  at  the  large 
number  of  divining-rod  operators  or  their 
varied  methods  of  working.  I  have  known 
some  remarkable  facts  about  divining  rods, 
but  the  final  results  in  every  case  have  had 


it,  and  this  induced  current  in  turn  induces 
a  high-frequency  oscillating  magnetic  field, 
which  reacts  on  the  original  magnetic  field, 
reducing  its  intensity. 

The  necessary  conditions  are  that  the  ore 
or  ores  sought  for  shall  be  conductors  of 
electricity,  for  the  method  described  enables 
the  location  of  an  electrical  conductor,  and 
the  fact  that  certain  ores  are  such  conduc- 
tors makes  their  location  possible.  An  ore 
that  is  not  electrically  conductive  cannot  be 
determined  by  this  method.  Native  meals, 
most  sulfids  and  chlorids,  but  very  few  car- 
bonats,  silicats  or  oxids  are  such  conduc- 
tors. 

The  progress  of  laboratory  experiments 


identical  exploring  coils  12  and  13  (Fig.  1), 
of  suitable  diameter  and  number  of  turns, 
are  connected  in  series  with  two  current 
rectifiers  16  and  a  sensitive  galvanometer 
17.  By  placing  one  of  these  exploring 
coils  at  a  measured  distance  from  the  cen- 
ter of  the  primary  coil  and  moving  the 
other  around  the  center,  the  induced 
currents  in  the  exploring  coils  being  op- 
posed to  each  other,  a  line,  along  which  the 
magnetic  flux  is  equal,  is  established  and 
may  be  plotted.  The  location  of  the  mov- 
able exploring  coil,  when  the  galvanometer 
reading  is  a  minimum,  determines  this  line, 
which  may  be  called  an  isogonic  line  and  is 
similar  to  a  contour  line  on  a  topographic 


The  Latest  Feat  in  Mining  Engineering  Is  the  Exact  Location  of  Underground  Metallic  Ores  by  Means  of  Induction.  The  Larger  Coil 
Is  Excited  by  a  High  Frequency  Current  from  a  Portable  Dynamo  Outfit.     The    Magnetic    Field   Created   Affects   the  Ore   Body,  Which 

Reacts   on    the    Smaller    Exploring  Coils  and  Indicating  Instruments. 


no  probability  of  development  to  a  condi- 
tion of  certainty  that  would  warrant  a 
business  investment,  and  almost  every 
operator  of  a  divining  rod  is  afflicted  with 
an  over-developed  imagination. 

In  an  effort  to  reach  the  desired  result 
of  being  able  to  determine  the  position  of 
an  orebody  under  the  surface  of  the 
ground,  the  idea  of  exploring  the  ground 
magnetically  was  conceived,  and  during  the 
last  three  years  has  been  developed,  first 
by  laboratory  work  to  establish  a  suitable 
method,  and  later  by  field  work  to  apply  the 
laboratory  method  to  actual  working  condi- 
tions, says  H.  R.  Conklin  in  Engineering 
and  Mining  Journal.  Patents  are  pending 
for  this  method,  which  will  be  of  interest 
in  many  fields  of  prospecting  work. 

If  a  high-frequency  oscillating  electric 
current,  such  as  is  used  in  wireless  tele- 
graphy, be  confined  to  a  closed  circular  cir- 
cuit, a  high-frequency  oscillating  magnetic 
field  is  induced  within  this  circuit,  and  the 
arrangement  becomes  a  solenoid  of  prac- 
tically no  length  and  of  large  diameter. 
Any  electrical  conductor  that  may  be  in- 
cluded in  this  induced  magnetic  field  will 
have  an  oscillating  current  induced  within 


was  slow  and  tedious,  and  the  difficulty  of 
adapting  these  experiments  to  field  work 
and  designing  the  necessary  instruments 
was  even  greater.  The  final  satisfactory 
results  are  shown  by  reference  to  Fig.  1,  in 
which  1  is  an  alternating-current  generator 
or  other  source  of  alternating  current,  sup- 
plying the  low-tension  coil  4  of  a  trans- 
former, through  a  regulating,  inductive  re- 
sistance 5.  The  high-tension  transformer 
coil  8  is  connected  to  a  suitable  spark  gap 
s  in  parallel  with  condensers  9  and  10  and 
the  primary  coil  11. 

The  primary  coil  11  is  laid  in  a  circle  on 
the  surface  of  the  ground,  and  within  it  is 
produced  the  oscillating  magnetic  field. 
This  magnetic  field  decreases  toward  the 
center  of  the  primary  coil  and  might  be 
plotted  as  shown  in  Fig.  2,  in  which  the 
ordinates  represent  change  in  magnetic 
flux.  Owing  to  unavoidable  variations  in 
the  original  source  of  power,  these  ordi- 
nates may  vary  during  observations  to  an 
extent  greater  than  their  diminution  due 
to  the  neighborhood  of  an  electrical  con- 
ductor, so  that  the  measurement  of  this 
magnetic  field  requires  a  balanced  method. 

For  measuring  this  magnetic  field,  two 


map.  In  the  latter  comparison  the  com- 
pleted plot  of  these  lines  suggests  contour 
lines  defining  a  depression,  as  shown  in 
cross-section  in  Fig.  2.  Now  if  the  mag- 
netic flux  be  decreased  as  at  A  in  Fig.  2, 
due  to  the  presence  of  a  conductor  of  elec- 
tricity, the  contour  lines  are  drawn  out  in 
the  direction  of  the  conductor,  and  the 
plotted  curves  are  distorted  from  the  nor- 
mal circular  form,  enabling  the  location  of 
the  conductor  to  be  determined. 

Several  sets  of  actual  distorted  contour 
lines,  as  determined  in  the  field,  are  shown 
in  Figs.  3  and  4.  All  were  observed  with 
the  primary  coil  two  hundred  feet  in  diam- 
eter. One  of  these  plots,  in  Fig.  4,  shows 
the  location  of  a  2-in.  iron  pipe  line  buried 
about  a  foot  underground,  and  is  also  dis- 
torted by  a  body  of  conductor  still  deeper. 

The  primary  coil  is  shifted  and  these 
contour  lines  plotted  for  a  sufficient  number 
of  centers  to  determine  the  general  size 
and  dimensions  of  the  body  of  conductor, 
after  which  prospect  drilling  is  done  to 
prove  the  depth,  thickness  and  quality  of 
the  conducting  orebody.  If  the  conducting 
orebody  be  below  and  nearly  symmetrical 
(Continued  on  page  501) 


442 


THE  ELECTRICAL  EXPERIMENTER 


November,  1917 


Seeing  Wireless  Signals 


OUR  front  cover  illustration  shows 
one  of  the  latest  wireless  signaling 
devices  perfected  by  Teutonic  ex- 
perts. With  this  device  the  recep- 
tion of  radio  messages  on  a  flying 
aeroplane  is  made  much  more  positive,  inas- 
much as  the  noise  from  the  engine  or  ma- 
chine gun  does  not  interfere  in  the  least 
with  it,  as  is  the  case  where  the  aerial  radio 
operator  has  to  listen  in  a  pair  of  sensitive 
head  telephones. 

We  are  indebted  to  William  Dubelier,  a 
radio-engineer  of  New  York  City,  for  the 
description  and  photograph  of  this  remark- 
able instrument,  who  personally  saw  this 
apparatus  in  the  Berliner  factory  at  Vienna, 
Austria,  and  besides  had  the 
pleasure  of  observing  signals 
being  received  from  a  distant 
station  with  it. 

This  apparatus  consists  of 
a  sensitive  Einthoven  galva- 
nometer with  a  small  electric 
lamp  shown  at  the  very  bot- 
tom of  the  photograph.  The 
light  from  this  lamp  is 
focused  thru  lenses  on  to  a 
small  mirror,  which  in  turn 
reflects  the  light  thru  a  mag- 
nifying glass,  the  same  as  in 
an  opera  glass.  The  upper 
part  thru  which  the  observer 
looks  is  constructed  on  the 
prismatic  binocular  principle, 
making  the  sighting  appara- 
tus equivalent  to  six  times  its 
length. 

In  other  words,  the  ob- 
server does  not  actually  see 
the  wireless  signal  or  wave 
literally  speaking;  he  only 
sees  the  effect  of  the  etheric 
wave,  after  it  has  impinged 
on  the  antenna  attached  to 
the  aeroplane,  and  after  it 
has  past  thru  the  tiny  quartz 
fiber  suspended  between  the 
poles  of  a  strong  magnet,  and 
perpendicularly  to  the  mag- 
netic flux  lines.  If  a  weak 
current,  such  as  a  received 
radio  signal  current,  passes 
thru  this  quartz  fiber,  the  lat- 
ter will  be  displaced  from  its 
normal  position  in  a  direction 
perpendicular  to  its  axis  and 
to  the  magnetic  flux  lines. 

The      fine  galvanometer 
string  moves  in  front  of  a 
narrow  slot,  illuminated  by 
the  small  lamp  fed  from  a 
battery  (see  illustration).  An 
optical  reproduction  of  the  slit  and  wire  is 
thrown  on  the  sensitive  retina  and  pupil  of 
the  eyes,  one  of  the  most  sensitive  devices 
we  know  of.  As  the  messages  come  in,  in 
the  form  of  telegraphic  dots  and  dashes- 
short  and  long  signals — the  quartz  string  is 
deflected  back  and  forth  correspondingly ; 
thus  the  radio  operator  "sees"  the  incoming 
signals.   A  short  deflection  indicates  a  "dot," 
while    a    longer    deflection    represents  a 
"dash." 

The  apparatus  just  described  and  here 
pictured  serves  the  same  function  as  the 
detector  used  in  all  radio  receiving  sets.  It 
is  usual  therefore  to  connect  it  with  some 
form  of  tuning  coil  or  transformer,  so  that 
the  outfit  can  be  readily  tuned  to  the  proper 
wave  length. 

As  the  front  cover  illustration  shows  the 
operator  holds  the  instrument  with  both 
hands,  or  only  one  hand,  if  he  desires  to 
write  down  the  message  received.  This  he 
can  readily  do  with  a  little  practise,  keep- 
ing one  eye  on  the  instrument  and  the  other 
on  the  message  pad  as  he  writes.    A  good 


operator  can  write  down  a  message  without 
looking  at  his  pen  or  pencil.  Besides,  it  is 
not  impractical  to  install  a  light  weight 
typewriter  on  the  aeroplane;  and  "touch 
typists"  never  have  to  look  at  the  keyboard. 
Radio  and  wire  telegraphists  are  daily  us- 
ing the  typewriter  in  just  this  way,  by  the 
thousand. 

The  principle  of  the  optical  and  photo- 
graphic reception  of  radio  signals  is  not 
new.  The  efficacy  of  the  Einthoven  string 
galvanometer  in  this  role  was  quite  thoroly 
tested  out  by  the  Poulsen  radio  experts, 
both  in  this  country  and  abroad.  The 
American  Poulsen  interests — the  Federal 
Telegraph  Company  of   San   Francisco — 


RUBBER  CUSHIONED 
E.YE-PIE.CE.   


BINOCULAR 
PRISMS   '  =*. 


HANDLE.   H 

GALVANOMETER 


HANDLE 


In  an  article  in  the  "Cologne  Gazette" 
on  a  visit  to  Kiel,  where  the  dockyards  are 
said  to  be  mainly,  but  not  entirely,  engaged 
with  repairing  work,  contains  the  follow- 
ing passage  on  copper  and  electricity : 

"Copper  is  now  used  in  large  quantities 
in  all  ships,  altho,  of  course,  consumption 
is  restricted  as  much  as  possible.  Espe- 
cially for  steam  piping  there  is  no  substi- 
tute for  copper,  and  it  is  also  needed  for 
all  purposes  where  high  resistance  to  sea 
water  and  salt  air  is  necessary. 

"Over  against  the  boiler  shop  is  the  elec- 
trical shop,  which  becomes  every  day  more 
important  with  the  increased  use  of  elec- 
tricity.   We  have  already  gone  a  long  way 
in   this   direction,   altho  we 

  have  not  yet  gone  quite  so 

far  as  the  Americans,  who 
even  drive  the  screw-shafts 
of  large  ships  by  electric 
motors.  As  regards  our  sub- 
marines, it  is  indeed  much 
the  same  with  us,  for  our 
submarines  already  consist 
half  of  electricity.  The  sub- 
marines are  also  concerned 
with  the  accumulator  shop, 
where  accumulators  are  re- 
paired. Repair  is  not  always 
possible,  for  the  demands 
made  on  the  accumulators  in 
war  are  sometimes  too  great." 


BOOKS 


SOL- 


Here  Is  the  Latest  Teutonic  War  Device.     It  Permits  the  Radio 
Operator  in  a  Flying  Machine  to  "See"  the  Wireless  Signals.  Thus 
the  Engine  and  Other  Noises  Do  Not  Bother  Him  In  the  Least. 

spent  many  thousands  of  dollars  in  their 
researches  on  this  method  of  receiving 
radio  signals,  the  only  difference  being  that 
the  movements  of  the  quartz  string  were 
highly  magnified  and  recorded  photo- 
graphically on  a  moving  film.  It  is  hopeful 
that  this  work  may  be  taken  up  again  and 
followed  up  to  a  successful  conclusion.  The 
United  States  needs  the  best  it  can  get  for 
every  branch  of  its  military  service  and  it 
would  seem  that  the  apparatus  here  de- 
scribed and  being  successfully  manufactur- 
ed in  Germany  can  certainly  be  duplicated, 
and  no  doubt  considerably  improved,  in  this 
nation  of  vast  industrial  and  scientific  re- 
sources. 


ELECTRICITY  AND  WAR  IN  LAND 
OF  THE  "HEINIES." 

The  "Frankfurter  Zeitung"  announces 
that  the  German  Government  has  requi- 
sitioned all  electrical  machinery  and  ap- 
paratus, and  it  is  not  now  possible  to  buy 
or  sell  electric  motors  without  special  per- 
mission. 


FOR  OUR 
DIERS. 

While  furnishing  books, 
magazines  and  other  litera- 
ture to  these  men, whom  we 
are  beginning  to  consider 
truly  "our  own,"  we  should 
not  forget  that  there  are, 
large  forces  in  France  with 
quite  as  keen  a  desire  for 
American  literature  and  with 
far  less  chance  of  having  it 
satisfied.  An  appeal  has  just 
been  issued  calling  attention 
to  this  need. 

In  New  York  City  books 
may  be  put  in  packages 
marked  for  the  "American 
Overseas  Force"  and  left  with 
any  public  library.  They 
should  be  in  fairly  good  con- 
dition. Magazines  are  wanted 
— and  contributors  are  re- 
quested not  to  send  periodi- 
cals more  than  two-years  old. 

The  type  of  books  our 
Sammies  enj oy  ?  Fiction  first ; 
then  French  grammars  and  dictionaries, 
first-year  French  books,  volumes  of  travel, 
biography,  history ;  books  on  aviation,  wire- 
less telegraphy,  submarines,  automobiles  and 
mechanics. 

Don't  forget  that  there  are  men  with  the 
overseas  forces  who  have  been  educated 
to  a  taste  for  the  best  of  literature.  "Sartor 
Resartus,"  or  "God,  the  Invisible  King," 
will  be  received  as  avidly  as  one  of  E. 
Philip  Oppenheim's  novels.  There  are  men 
in  the  army  with  Harvard  and  Yale  and 
Cornell  educations — and  with  a  correspond- 
ing literary  appetite.  And  the  army  also 
includes  men  with  little  schooling.  Con- 
sequently you  have  a  broad  and  almost  un- 
limited field  for  literary  charity,  and  don't 
fail  to  read  the  notice  on  the  front  cover  of 
this  journal. 


THE  ELECTRIC  TAXI. 

For  crowded  traffic  (ease  of  control), 
simplicity,  ease  of-  operating  and  freedom 
from  engine  troubles,  the  electric  taxi  is 
coming  well  into  favor. 


November,  1917 


THE  ELECTRICAL  EXPERIMENTER 


443 


Microphones  in  Trench  Warfare 


THERE  is  hardly  a  spot  on  earth 
today  where  modern  science  receives 
as  many  professional  tryouts  as  in 
our  war  trenches.  New  methods,  new 
schemes,  new  inventions  are  being  tried  out 
forever,  and  like  many  another  game  it 
settles  down  to  a  game  of  wits  where  that 
side  having  the  most  brains  and  the  most 
ingenuity  is  likely  to  win  out  in  the  end. 


By  H.  GERNSBACK 


be  obtained  by  what  is  popularly  called 
the  dictagraph.  But  the  question  im- 
mediately comes  up,  how  are  the  dicta- 
graphs to  be  placed  in  the  enemy's 
trenches?  Of  course,  while  it  is  rather  a 
ticklish  business,  it  is  not  impossible  and 
our  illustration  shows  how  it  could  be 
readily  accomplisht. 
We  first  need  our  sensitive  microphones 


will  not  be  discovered.  It  should  be  re- 
membered that  grass  or  vegetation  grow- 
ing over  the  microphones  as  well  as  over 
the  fine  cable  will  practically  conceal  both 
entirely  from  view.  The  same  is  true  of 
dust  and  sand,  etc.,  which  all  aid  in  hiding 
the  microphone.  Naturally  a  microphone 
of  this  kind  must  be  rugged  and  the  ar- 
rangement should  be  such  that  no  matter 


Listening  to  the  Doings  in  the  Enemy's  Trenches  By  Means  of    Supersensitive    Microphones   Is  a  Recent  Idea.     It  Shows  a  New 
Way  How  to  Get  Advance  Information,  as,  for  Instance,  Just  When  the  Enemy  Intends  to  Attack,  Etc.,  Etc. 


When  two  forces  are  deadlocked  against 
each  other  and  when  it  becomes  practically 
impossible  to  pass  over  the  intervening 
"No  Man's  Land"  with  assailing  forces,  it 
is  of  primary  importance  to  know  what  is 
going  on  in  the  other  fellow's  trenches. 
It  being  impossible  to  raise  the  head  above 
the  parapet  due  to  continuous  bullet  streams, 
the  men  in  the  trenches  are  more  or  less 
on  edge  continuously,  as  they  do  not  know 
what  is  going  to  happen  next.  Consequently 
most  of  the  reconnoitering  is  done  during 
the  night,  and  to  counteract  this  the  enemy 
uses  the  so-called  star-shells  which  illu- 
minate the  landscape  for  miles  around  for 
a  period  of  a  few  seconds.  During  this 
time  there  is  always  an  opportunity  to 
catch  advancing  forces  or  patrols  and  thus 
annihilate  them. 

The  thing  that  a  commander  is  most  in- 
terested in,  is  to  know  just  when  the  enemy 
is  going  to  leave  his  trenches  to  make  an 
attack.  If  he  could  know  exactly  at  what 
time  such  an  attack  is  to  be  made,  this 
information  would  often  be  of  priceless 
value.  Of  course,  it  goes  without  saying 
that  the  enemy  is  not  likely  to  give  away 
such  information  if  he  can  help  it.  Ad- 
vance posts  in  advanced  trenches,  called 
in  field  parlance  "listening  posts,"  are  of 
course  quite  satisfactory,  but  they  do  not 
get  advance  information,  and  they  are 
simply  there  to  stop  an  advancing  force 
or  to  tell  the  men  behind  the  lines  as  soon 
as  the  attack  has  started.  This  listening 
post  is  usually  a  shell  hole  somewhere  be- 
tween the  trenches  in  "No  Man's  Land" 
well  fortified  with  sand  bags,  and  well  in 
advance  of  the  front  trenches.  It  is  usually 
manned  by  two  men,  and  a  machine  gun  or 
sometimes  rifles  only.  It  has  occurred  to 
us  that  advance  information  could  readily 


properly  camouflaged  so  they  will  have  a 
rather  innocent  appearance.  In  other 
words,  they  could  be  made  up  as  cobble- 
stones, pieces  of  log,  or  any  other  object 
that  would  not  arouse  the  suspicion  of  the 
enemy.  It  would  then  be  the  duty  of  some 
of  the  men  to  take  these  thus  camouflaged 
sensitive  microphones  up  to  the  very  edge 
of  the  enemy's  trench,  concealing  the  mi- 
crophones behind  his  parapet  and  sand 
bags. 

Needless  to  say  in  doing  so,  it  is  neces- 
sary for  the  party  who  lays  the  micro- 
phones to  clear  the  barbed  wire  entangle- 
ments, and  this  is  ticklish  business.  Inas- 
much as  these  wire  entanglements  are  often 
provided  with  cowbells  and  other  ingeni- 
ous tell-tales  which  immediately  inform  the 
enemy  that  someone  is  near,  the  trick  can 
be  accomplisht  nevertheless.  For  instance, 
the  microphone  may  be  thrown  by  hand  like 
a  bomb,  taking  good  aim  that  it  does  not 
actually  land  into  the  trenches ;  thin  wire 
trailing  from  behind  the  microphone  and 
which  should  have  the  same  color  as  the 
ground,  will  not  be  readily  detected  by  the 
enemy.  In  this  case,  the  wire  would  of 
course  lay  on  top  of  the  barbed  wire  en- 
tanglements, but  being  very  fine  it  probably 
would  not  be  observed  from  the  enemy's 
trench. 

Naturally  all  this  work  must  be  done  dur- 
ing a  dark  night,  it  being  impossible  to 
crawl  out  of  the  trenches  in  "No  Man's 
Land"  during  the  day-time  without  courting 
certain  death.  It  also  goes  without  saying 
that  the  enemy  will  surely  discover  some 
of  the  microphones  in  time  and  shoot  them 
to  pieces. 

However,  it  should  be  possible  to  place 
enough  of  them  in  such  a  manner  that  at 
least  a  few  will  stay  in  place  where  they 


how  the  microphone  is  thrown,  it  should 
operate  to  its  full  sensitiveness.  This, 
however,  presents  no  unsurmountable  tech- 
nical difficulty,  any  electrical  engineer  being 
capable  of  designing  a  microphone  of  this 
kind. 

Now  suppose  we  have  a  few  dozen  of 
these  microphones  concealed  near  the 
enemy's  trench.  The  wires  from  them  lead 
to  our  own  trenches,  where  an  operator  is 
to  be  in  charge  of  the  receiving  end,  listen- 
ing for  any  information  coming  over  his 
wire ;  chance  remarks  by  the  enemy  are 
surely  to  be  made  from  time  to  time.  But 
not  alone  is  information  such  as  this  of 
high  import,  but  our  commanders  need 
very  much  more  certain  information  as  for 
instance,  when  the  men  in  the  first  trench 
line  are  to  be  relieved. 

In  trench  warfare,  the  men  of  course 
cannot  stay  in  the  trenches  all  of  the  time, 
and  they  are  usually  relieved  during  the 
night-time,  which  means  more  or  less  con- 
fusion, "choked"  trenches,  etc.  If  our  at- 
tack can  be  timed  at  such  a  period,  it  is 
naturally  more  easy  to  win  a  trench  than 
when  the  regular  forces  are  in  charge.  The 
noise  and  the  talk  of  the  relieving  party 
should  usually  be  loud  enough  to  give  such 
information  away  over  the  sensitive  micro- 
phone. 

Of  course,  a  scheme  of  this  kind  can 
readily  be  improved  upon  in  many  ways, 
and  we  leave  this  to  our  able  Signal  Corps 
attendants  at  the  front. 


ITALY  USES  RADIO-TELEPHONES 

So  successful  have  wireless  telephones 
proved  on  Italian  warships  that  the  gov- 
ernment plans  to  install  them  on  merchant 
and  passenger  vessels. 


444 


THE  ELECTRICAL  EXPERIMENTER 


November,  1917 


"Movies"  Show  Women's  Place  in  War 


IN  these  trying  days  of  strife  when  on 
all  sides  nations  are  in  the  grip  of  war 
the  "movies,"  as  usual,  have  their  full 
play  on  the  subject.  Always  of  keen 
interest  to  young  and  old,  kiddies  as 
well  as  grown-ups,  the  photoplays  are  giv- 
ing their  best  to  the  portrayal  of  war  in 
all  its  grim  reality.  Every  detail  receives 
the  utmost  consideration;  especially  is  this 
true  where  the  uses  of  electricity  and  mod- 
ern invention  are  involved. 

From  the  large  number  of  photoplays 
now  before  the  public  the  following  essay 
and  photos  have  been  chosen,  showing  how 
women  may  help  at  home,  by  "Taking  the 
Man's  Place,"  and  by  so  doing,  allowing 
every  brave  and  true-hearted  American  an 


the  Sussex  dairy  maids  by  the  time  you 
receive  this  letter." 

This  was  the  war's  effect  upon  Lady 
"W."  It  is  typical  of  what  has  happened 
thruout  Europe  and  what  must  certainly 
occur  in  this  country,  if  the  war  continues 
two  years  longer. 

Already  women  are  training  for  various 
vocations  and  are  replacing  our  first  quota 
of  the  Grand  Army.  As  a  "lineman,"  the 
woman  will  fit  in  very  nicely,  having  held 
the  reputation  of  working  wires  so  long 
that  making  a  profession  of  this  pursuit 
will  not  be  new.  It  is  true,  they  will  be 
very  much  up  in  the  air  about  it,  as  any- 
one can  see  from  the  accompanying  photo- 
graphs, which  show  a  fair  female  lineman — 


ing   when  the  time   comes  we  are  sure. 

Then  again  as  a  "Wireless  Operator," 
the  woman  can  very  well  fill  positions  in 
this  interesting  and  fascinating  art.  There 
is  a  fifteen  year  old  girl  now  living  at  San 
Raphael,  Cal,  who  has  received  a  first 
grade  commercial  radio  operator's  license 
from  the  United  States  Government.  Her 
name  is  Kathleen  Parkin,  and  she  took 
up  the  work  after  becoming  interested  in 
it  in  the  physics  laboratory  of  the  high 
school  she  attended.  Wireless  operating, 
in  fact,  seems  to  be  a  form  of  employ- 
ment peculiarly  adapted  to  women.  Girls 
hold  the  majority  of  places  at  telephone 
switchboards  and  quite  a  number  in  tele- 
graph offices,   so   it   seems  reasonable  to 


opportunity  to  do  his  bit  in  the  fight  ■ 
for  democracy.  The  following  is  H 
typical  of  the  change  that  has  been  S 
wrought  abroad  at  the  present  time,  I 
and  who  knows,  but  what  the  same  pi 
might  happen  in  the  good  old  U.  S.  H 
A.  Lady  "W,"  at  the  beginning  of  H 
the  war,  lived  in  a  palatial  mansion  " 
in  an  exclusive  section  of  the  big 
metropolis.  She  sipt  her  coffee  in  bed 
every  day  at  noon,  motored  about  the  Eng- 
lish capital  and  gossiped  over  her  tea  with 
other  ladies  every  day  at  dusk.  At  dinner 
she  became  finical  over  the  iilct  mignon. 
after  which  she  drove  to  the  opera  or  to 
a  social  function  given  by  one  of  her 
friends.  She  was  the  kind  of  a  woman 
who  thought  life  impossible  without  two 
maids  at  least,  a  manicurist  and  some  one 
to  look  after  her  pet  dogs. 

Recently  one  of  her  friends  received  a 
letter  as  follows :  "I  shall  soon  ?o  into 
the  fields,  and  'do  my  bit'  along  with  the 
other  women  who  have  turned  farm  la- 
borers. Ever  since  the  horror  of  this  war 
first  broke  on  me,  I  have  done  everything 
that  I  could  to  alleviate  the  suffering  of 
the  poor  boys  who  are  stricken  by  it. 

"My  home,  as  you  already  know,  has 
been  turned  into  a  hospital.  I,  myself, 
have  nursed  many  wounded  men  back  to 
health.  I  have  spent  days  and  often  nights 
rolling  bandages,  mending  and  disinfect- 
ing clothes..  Now  I  believe  I  am  needed 
in  the  fields,  and  I  shall  probably  be  among 


beg  pardon,  linewoman — one  Miss  Gladys 
Brockwell,  in  the  Fox  photoplay,  "Taking 
the  Man's  Place."  Seriously,  however,  act- 
ing as  telephone  and  telegraph  linemen  is 
not  a  completely  foreign  occupation.  Of 
the  38,000  persons  now  employed  in  this 
occupation,  600  are  women. 

Many  dangers  are  encountered  by  the 
man  whose  task  it  is  to  see  that  the  elec- 
trical communication  lines  are  not  broken. 
He  must  climb  to  the  top  of  the  highest 
pole,  cling  among  a  nest  of  wires  with  a 
narrow  belt  as  his  only  support.  While 
there,  he  must  see  that  all  apparatus  is  in 
working  order.  He  has  often  to  go  into 
lonely  stretches  of  the  country,  where  at 
any  minute,  he  is  liable  to  be  attacked  by 
fierce  beasts  or  still  fiercer  men.  He  must 
also  expose  himself  to  rigorous  weather 
and  he  frequently  spends  the  night  among 
poisonous  marsh  gases. 

All  of  these  hazards  the  women  are  will- 
ing to  encounter.  They  have  heretofore 
given  many  instances  of  moral  courage. 
Physical  courage,  which  is  a  much  com- 
moner thing,  they  will  be  capable  of  show- 


suppose  that  they  can  just  as  well 
tap  the  key  of  a  radio  station.  The 
marine  laws  of  this  country  re- 
quire the  presence  of  two  wireless 
operators  on  each  ship.  I  once 
knew  a  girl  who  held  a  position 
on  board  a  steamer.  Her  fellow 
telegrapher  was  of  masculine 
gender;  so  to  avoid  losing  her  job 
she  married  him. 

In  time  of  war,  it  is  especially 
important  that  all  telephone,  tele- 
graph and  radio  communications 
be  kept  free  from  the  least  in- 
terruption and  damage.  Military 
units  in  widely  different  parts  of 
the  country  must  be  acquainted  with  the 
movements  of  their  troops.  Orders  from 
the  commanding  officers  must  be  sent  im- 
mediately to  subordinate  officers  of  the 
line.  Old  men  and  young  boys  will  be  in- 
capable for  all  the  jobs,  and  Uncle  Sam 
will  be  forced  to  turn  to  the  women  and 
ask  for  their  help.  One  thing  seems  ab- 
solutely certain : 

When  the  call  comes,  the  women  will 
be  ready! 


One  of  the  newest  New  York  hotels  is 
electrically  equipt  from  top  to  bottom. 
Hardly  an  electric  appliance  of  the  many 
which  contribute  so  much  to  happy,  com- 
fortable living  has  been  omitted.  Electric 
refrigerators,  dumb-waiters,  stoves,  fans, 
vacuum  cleaners,  'phones,  calls  of  all  de- 
scription, the  most  improved  and  modern 
lighting,  and  a  host  of  other  electrical  ap- 
pliances. This  model  hostelry  is  called 
Hotel  des  Artistes,  and,  as  the  name  im- 
plies, is  especially  conducted  for  artists, 
illustrators,  writers,  and  those  of  allied  qc- 
cupations. 


November,  1917 


THE  ELECTRICAL  EXPERIMENTER 


445 


How  Big  Electric  Men  Work 


D 


j-*DITOR'S  foreword. — The  present  arti- 
wj.  de,  especially  prepared  for  "The  Elec- 
trical Experimenter,"  is  one  of  great 
interest  to  all  of  us,  and  particularly  to  elec- 
trical readers  who  follow  the  lives  of  big  men 
in  their  reading.  It  is  not  often  that  one  has 
the  unusual  opportunity  of  observing  at  close 
range  just  how  such  men  as  Edison,  de 
Forest  or  Pupin  accomplish  the  day's  duties. 
Besides  making  interesting  reading  you  will 
find  in  the  following  paragraphs  some  of 
the  principles  involved  in  the  working  out 
of  these  men's  goal — Success! 

,R.  LEE  DE  FOREST, 
the  well-known  radio 
engineer  and  inventor, 
is  one  of  the  greatest  radio 
students  today.    Besides  be- 
ing president  of   his  own 
company,    now  extremely 
busy  on  war  orders,  he  still 
finds  time  to  carry  on  re- 
searches in  wireless.  When 
I  asked  Dr.  de  Forest  how 
he  tackled  the  day's  problems,  he  said : 

"My  daily  work  begins  promptly  at  eight 
o'clock.  I  first  go  over  my  mail  and  decide 
what  matters  require  immediate  attention 
and  what  can  be  postponed  to  more  leisure- 
ly moments.  Before  beginning  my  dicta- 
tion I  go  rapidly  thru  the  Laboratory  and 
Shop  to  check  up  the  various  jobs  and  see 
what  progress  has  been  made,  and  what 
are  the  needs  in  the  way  of  information  or 
advice  of  the  men  in  charge  of  the  various 
jobs.  This  is  to  avoid  any  delays  which 
occur  if  I  postpone  this  work  until  thru 
with  my  office  work  for  the  day. 

"I  then  shut  myself  in  the  office  and 
endeavor  to  do  at  once  all  the  dictating 
which  has  to  be  done  for  that  day.  I  am 
usually  thru  with  this  work  by  nine-thirty. 

"I  then  go  carefully  over  the  work  in  the 
Laboratory,  Audion  and  Oscillion  Depart- 
ments. In  these  days  when  we  are  so  rushed 
to  get  out  instruments  of  various  types 
urgently  needed  for  the  Army  and  Navy, 
I  frequently  help  in  the  testing  of  the  ap- 
paratus. I  find  this  keeps  me  most  inti- 
mately in  touch  with  the  exacting  require- 
ments which  must  be  met  in  this  Govern- 
ment apparatus.  Occasional  faults  in  design 
present  themselves,  or  some  careless  or 
hasty  work  on  the  part  of  some  of  the 
employees  which  must  be  corrected  before 
it  goes  further. 

"About  noon  I  am  usually  ready  to  make 
a  second  trip  of  supervision  thru  the  fac- 
tory. Lunch  hour  consists  of  eating  a  few 
sandwiches  while  seated  at  my  desk,  and 
usually  consumes  less  than  fifteen  minutes. 
This  affords  me  a  good  opportunity  to 
check  over  my  memoranda  as  to  various 
matters  which  will  require  my  attention 
during  the  afternoon. 

"It  is  frequently  necessary,  even  in  these 
busy  days,  to  go  to  New  York  City  to 
consult  with  my  Patent  Attorneys,  manu- 
facturers, chemists,  or  engineers  with 
whom  we  are  doing  business  or  obtain- 
ing materials  from.  These  outside  trips 
are  always  confined  to  the  afternoon  and 
I  make  every  effort  to  so  arrange  them  that 
I  can  get  back  to  the  factory  before  closing 
time  in  order  to  go  over  all  the  mail  of  the 
day,  checking  up  and  signing  the  corre- 
spondence, and  laying  'out  the  necessary 
tasks  which  are  to  be  undertaken  the  next 
morning. 

"The  present  program  permits  practically 


By  GEORGE  HOLMES 

no  experimental  or  research  work  during 
working  hours.  All  such  work  has  to  be 
now  limited  to  nights  and  Sundays,  altho 
it  is  really  surprising  how  much  of  this 
development  work  can  be  done  here  and 
there  between  times  when  testing  out 
standard  apparatus,  etc.,  provided  only  that 
this  development  work  is  along  strictly 
similar  lines,  such  as  improvements  in  the 
design  of  Audions,  or  Oscillion  tubes,  re- 
finements of  circuits,  improvement  in  me- 
chanical and  electrical  designs,  etc. 

"Under  these  circumstances  most  of  the 
details  of  data-making,  quantitative  meas- 
urements, etc.,  must  be  left  to  my  assist- 
ants whose  time  can  be  uninterruptedly 
devoted  to  their  individual  tasks. 

"My  reading  and  study  work  are  limited 
to  hours  at  my  home,  which  fortunately  is 
located  fifteen  minutes  by  automobile  from 
my  Laboratory.  This  work  is  always  done 
at  night  and  is  usually  terminated  between 
eleven  and  twelve  o'clock. 

"It  is  a  source  of  genuine  regret  that  in 
these  exceedingly  busy  and  strenuous  times 
my  duties  do  not  permit  me  to  concentrate 
as  has  been  my  habit  and  delight  for  days 
and  weeks  at  a  time  on  some  problem  or 
investigation.  It  is  only  by  such  concentra- 
tion that  revolutionary  results  are  obtained 
but  under  the  circumstances  which  sur- 
round us  this  form  of  work  must  unfor- 
tunately be  postponed  to  more  tranquil 
times." 

PROF.  MICHAEL  I. 
PUPIN  of  Columbia 
University,  a  striking 
figure  in  the  electrical  world 
and  instructor  of  Electro- 
Mechanics  at  that  Institu- 
tion, is  an  unusually  busy 
person  as  is  general  with 
men  in  the  public  eye.  His 
pleasing  personality  and 
good  will  towards  all  who 
know  him  is  remarkable,  when  one  con- 
siders the  numerous  tasks  that  confront 
him  in  the  course  of  a  day. 

Aside  from  the  various  classes  at  the 
University  and  time  devoted  to  various 
technical  meetings,  etc.,  he  still  has  time 
for  experimentation  and  research.  At  the 
time  of  the  author's  visit  to  his  wonderful 
laboratory  at  Columbia,  Prof.  Pupin  and 
his  assistant  were  engaged  in  experiments 
on  a  new  form  of  rotor  for  high  frequency 
alternators. 

Regarding  his  general  layout  or  plan  of 
work,  he  said  among  other  things — "That 
'Big'  men  do  not  plan  out  their  day's  work, 
but  just  take  it  as  it  comes" — which  saying 
is  very  true  when  one  considers  the  numer- 
ous problems  that  arise  daily  in  the  work 
of  such  a  man.  Of  course,  there  is  always 
a  schedule  kept  as  to  the  classes  to  come 
and  the  series  of  experiments  to  be  con- 
ducted, but  usually  there  is  much  that  has 
to  be  taken  care  of  just  as  it  comes. 

Taken  all  in  all,  Prof.  Pupin  is  one  of 
the  busiest  personages  ever  interviewed. 
However,  from  appearances  one  would 
never  judge  him  to  be  one  of  the  leading 
scientists  of  the  day,  as  he  takes  his  work 
coolly,  quietly  and  deliberately,  even  in  the 
most  strenuous  periods  and  is  always 
pleased  to  meet  a  fellow  experimenter  and 
chat  for  a  few  moments  on  topics  of  elec- 
trical and  scientific  interest.  . 


THOMAS  A.  EDISON, 
master  electrician, 
chairman  of  the  United 
States  Naval  Advisory 
Board,  holder  of  more  pat- 
ents than  any  other  man 
living,  inventor  of  the  in- 
candescent lamp,  phono- 
graph and  motion  picture 
machine — how  does  such  a 
dynamically  active  human 
genius  get  thru  the  day's  work? 

In  answer  to  this  question  as  to  tin 
routine  followed  by  Mr.  Edison  in  goin;^ 
thru  the  day's  work,  it  may  be  said  thai 
the  term  "routine"  would  scarcely  be  ap- 
plicable in  his  case.  In  other  words,  Mr. 
Edison  usually  has  in  progress  a  number 
of  investigations  and  experiments  which 
he  is  either  conducting  in  person  or  with 
the  aid  of  his  large  staff  of  experimenters. 

One  or  more  of  these  investigations  or 
experiments  may  be  the  subject  of  a  stren- 
uous campaign  continuing  day  and  night 
without  intermission,  while  others  may  be 
along  lines  of  work  requiring  months  and 
in  some  cases  even  years  of  experimenta- 
tion. As  an  instance  of  the  latter  class, 
there  was  one  case  where  Mr..  Edison  had 
an  expert  experimenting  upon  one  singL- 
line  of  phonograph  recording,  under  hi> 
supervision,  for  15  years  before  arriving  at 
satisfactory  results. 

Altho  Mr.  Edison  is  a  good  business  man, 
as  well  as  an  inventor,  he  does  not  keep  a 
calendar  of  engagements,  Directors'  meet- 
ings, et  cetera,  but  figures  on  having  all  the 
time  there  is,  day  and  night,  for  his  ex- 
perimental and  inventive  work,  leaving  it 
to  his  son,  Mr.  Charles  Edison,  and  his  as- 
sistant, Mr.  W.  H.  Meadowcroft,  to  watch 
out  and  see  that  he  attends  to  the  com- 
paratively few  appointments  that  have  been 
made  for  him. 

He  never  attends  to  the  details  of  open- 
ing any  mail.  There  is  a  tremendous  stream 
of  letters  flowing  to  him  constantly,  but 
these  are  opened  for  him,  and  only  those 
requiring  his  personal  attention  are  brought 
to  his  notice.  His  assistants  strive  to  save 
him  in  every  detail  that  is  possible,  especial- 
ly when  he  is  on  one  of  his  strenuous  cam- 
paigns, during  which  he  will  often  average 
20  hours  work  a  day  for  a  long  period  of 
time.  During  these  campaigns  everything 
is  boiled  down  to  the  extreme  point,  in 
order  that  he  may  be  enabled  to  concentrate 
his  attention  on  the  work  in  hand  to  the 
utmost  possible  limit. 

His  days  and  nights  are  crowded  with 
work,  and  he  has  no  regular  schedule  that 
could  be  called  routine.  He  devotes  all  his 
thought  and  energy  to  the  work  which  is 
in  hand  at  the  time,  and  he  has  no  thought 
whatever  for  the  clock. 

Ordinarily,  he  comes  down  to  the  Lab- 
oratory right  after  breakfast  and  plunge, 
immediately  into  work  the  moment  he  ar- 
rives, oblivious  of  all  else  that  is  going  on 
around  him.  It  must  be  noted,  however, 
that  he  will  find  time  to  keep  in  close  touch 
with  his  extensive  business  interests  by  oc- 
casional consultation  with  the  various  man- 
agers and  a  rapid  examination  of  reports  of 
the  operations  of  the  various  departments, 
his  capacious  memory  enabling  him  in  this 
way  to  keep  his  finger  on  the  pulse  all  the 
time. 

No  man  exists  who  is  happier  than  Mr. 
Edison  when  he  has  some  new  problems  to 
solve. 


446 


THE  ELECTRICAL  EXPERIMENTER 


November,  1917 


Something  New  in  Microphones 


THE  microphone  or  sound  wave 
transmitter  now  used  in  all  standard 
telephone  and  similar  apparatus,  has, 
to  all  practical  intents  and  purposes, 
-  remained  the  same  for  many  years 
in  its  general  make-up.  That  is,  it  has 
comprised  a  metal  or  mica  diafram  about 
three  inches  in  diameter,  and  when  the 
voice  waves  in  the  air  impinge  against  this 
diafram,  they  cause  it  to  vibrate  on  its  full 
diameter  as  an  axis.  When  this  occurs,  a 
small  carbon  button,  secured  to  the  center 
of  the  diafram,  is  caused  to  exert  a  vary- 
ing pressure  against  a  number  of  small 
carbon  grains  held  in  a  carbon  cup  in  jux- 
taposition to  the  aforesaid  carbon  disc  car- 
ried by  the  diafram.  The  accompanying  il- 
lustrations show  something  quite  new  in 
the  realm  of  microphones,  which  has  just 
been  invented  by  William  and  James  Bir- 
rell. 

The  new  transmitter  here  illustrated  is 
the  result  of  much  research  work  by  these 


means  of  holding  it  in  place.  With  this 
simple  change,  and  connecting  one  cell  of 
dry  battery  at  each  end  of  the  line,  into 
which  35  miles  of  cable  had  been  connected, 
the  spoken  voice  emerged  clear  and  distinct. 

One  of  the  illustrations  herewith  pro- 
duced shows  an  interesting  and  most  re- 
markable test  made  with  this  transmitter, 


Most  important  of  all,  this  microphone 
is  one  of  the  simplest,  if  not  the  simplest 
ever  devised,  considering  its  extremely 
high  efficiency;  which  compares  favorably 
with  any  of  the  standard  microphones  now 
in  use.  It  has  but  twelve  parts  in  its 
make-up,  and  the  arrangement  of  these 
parts  is  apparent  from  the  accompanying 
photograph.  One  of  the  most  interesting 
facts  about  this  transmitter  is  that  no 
mouthpiece  is  necessary,  even  when  talking 
over  long  circuits  with  it,  as  is  invariably 
the  case  with  all  of  the  usual  microphones 
with  which  we  are  familiar. 


WOMEN  ELECTRICAL 
ENGINEERS. 

One  hundred  and  fifty  young  women  will 
study  to  become  electrical  engineers  at  the 
State  Agricultural  College  of  Kansas  the 
coming  year.    Because  of  the  war  many 


Left:   Even  When  Submerged  the  New  Transmitter  Gave  Perfect  Transmission  Thru  Surface  of  Water.  Center:  A  Casing  Is  Not  Required 
for  Talking.    Right:  Front  and  Rear  Views  of  New  Microphone  Showing  Construction  Details. 


engineers,  who  have  made  a  close  study  of 
this  instrument,  and  its  operating  principle 
is  rather  one  of  agitation  of  the  carbon 
granules  between  the  carbon  electrodes, 
than  it  is  of  compression,  as  in  the  old 
type. 

It  is  quite  remarkable  what  this  new  form 
of  microphone  will  do.  For  instance,  the 
diafram  may  simply  be  held  in  the  hand 
as  shown  in  one  of  the  accompanying  il- 
lustrations, and  the  transmitter  will  talk 
loudly  and  clearly  over  a  telephone  circuit 
of  considerable  length.  It  has  been  tested 
out  on  actual  telephone  circuits  up  to  107^ 
miles  in  length ;  this  circuit  consisting  of 
100  miles  of  standard  metallic  line  and 
7y2  miles  of  farm  line,  which  latter  was 
mostly  barbed  wire  fence.  In  another  test, 
on  a  telephone  train  dispatching  circuit 
near  Chicago,  this  transmitter  was  success- 
fully tested  out  on  a  443  mile  stretch  of 
line,  and  the  voice  was  remarkably  clear 
and  distinct,  regardless  of  the  fact  that  a 
number  of  train  dispatching  telephone  sta- 
tions were  connected  in  on  the  line  at  the 
time. 

This  transmitter  can  be  placed  in  any 
standard  telephone  microphone  chamber, 
such  as  found  on  desk  stands  or  wall 
'phones,  and  all  that  is  necessary  is  to  re- 
move the  old  transmitter  parts,  including 
the  bridge  arm,  and  placing  the  new  trans- 
mitter of  the  type  herewith  shown  inside 
the  chamber,  using  the  old  damping  springs 
which  had  been  left  in  position,  as  the 


in  which  it  was  submerged  in  a  small  fish 
aquarium  filled  with  water,  and  also  con- 
taining several  gold  fish.  Wonderful  to  re- 
late, and  contrary  to  what  might  invariably 
be  expected  with  such  a  delicate  device  as 
the  microphone,  this  particular  instrument 
succeeded  in  transmitting  the  voice  per- 
fectly thru  35  miles  of  artificial  cable, 
while  it  was  submerged,  and  moreover, 
with  the  mica  disc  covering  the  carbon 
grains  punctured,  so  as  to  allow  the  water 
to  enter  the  carbon  cup. 

One  of  the  illustrations  herewith,  shows 
a  young  lady  making  this  test,  the  sound 
waves  passirlg  first  thru  the  air  and  then 
thru  the  water  to  reach  the  submerged 
microphone. 

With  respect  to  the  resistance  of  this 
new  microphone,  a  number  of  tests  gave 
its  value  at  50  ohms,  when  the  receiver 
was  removed  from  the  hook,  and  with  no 
talking  or  other  noise  in  the  vicinity.  As 
soon  as  voice  waves  impinged  on  the  trans- 
mitter, its  resistance  increased  to  from 
105  to  110  ohms,  and  it  proceeded  to  vary 
between  110  ohms  and  60  ohms,  the  resis- 
tance not  returning  to  the  normal  50  ohm 
value  at  any  time.  The  current  consump- 
tion with  four  dry  cells  in  circuit  with  the 
microphone,  varied  from  .09  ampere  with 
no  talking  to  .04  ampere  when  talking 
started.  When  but  one  dry  cell  was  tested 
in  circuit  with  the  microphone,  the  current 
consumed  varied  from  .02  ampere  to  a  little 
under  .01  ampere. 


engineers  have  left  their  positions  and  it 
will  not  be  a  great  while  before  the  short- 
age will  be  keenly  felt.  "Women  are  being 
employed  as  power  plant  operators  in  the 
large  central  stations  of  Europe,"  said 
Clarence  E.  Reid,  professor  of  electrical  en- 
gineering at  the  college,  "and  have  been 
found  entirely  satisfactory. 

"None  of  the  machinery  in  these  stations 
is  operated  by  hand,  but  is  all  controlled 
by  various  forms  of  electric  motors  set 
into  operation  by  the  touch  of  a  button  or 
by  electro-magnets  or  air  pressure  con- 
trolled in  the  same  manner,  so  that  physi- 
cal strength  is  not  at  all  necessary.  Work 
of  this  kind  is  far  less  exhausting  than 
many  forms  of  work  in  which  women  are 
now  engaged,  for  central  station  opera- 
tors may  use  seats  and  have  more  variety 
of  movement  in  their  work.  Desirable 
qualifications  for  entering  upon  engineering 
study  comprise  ability  in  mathematics  and 
interest  in  scientific  study." 


Electrical  heating  blankets  are  now  of- 
fered to  those  who  sleep  out-doors,  for 
hospital  and  sick-room  use,  for  elderly 
people  or  those  with  poor  circulation.  These 
blankets  come  as  large  as  6  x  5  feet ;  have 
three  temperature  controls,  ranging  from 
82  to  112  degrees.  The  cost  of  running  is 
almost  negligible.  The  item  of  lightness 
as  compared  to  much  heavier  bedclothes 
is  an  important  consideration. 


November,  1917 


THE  ELECTRICAL  EXPERIMENTER 


447 


HOW  AFRICA  GETS  THE  WAR 
NEWS. 

The  war  has,  from  the  first,  been  brought 
right  home  to  Africa.  The  four  German 
colonies,  over  which  the  war  extended,  have 
an  area  more  than  four  times  as  great  as 
Germany ;  and  there  has  been  long  and  hard 
fighting  in  all  of  them  except  in  Togo.  Out- 
side and  within  these  areas  of  actual  war- 
fare live  thousands  of  whites  who  are  in- 
tensely interested  in  the  European  struggle. 
It  may  surprise  many  to  know  that  not  a 
few  of  these  whites,  even  in  the  depths  of 
Africa,  are  receiving  the  essence  of  the 
news  every  day  and  are  well  informed  as 
to  the  most  vital  facts  of  the  day's  war 
history. 

Even  the  Sahara  Desert  is  now  partly 
belted  by  a  telegraph  line,  a  French  enter- 
prise, with  wireless  extension  to  Timbukto. 
Thus  this  once  mysterious  city  of  the  Su- 
dan is  now  in  touch  with  the  great  events 
of  the  day.  The  Belgian  Congo  is  efficient- 
ly served  by  the  French  cable  to  Libreville 
and  the  land  line  to  Stanley  Pool,  where 
navigation  of  the  Upper  Congo  begins.  The 
news  is  then  wired  up  the  Congo  to  the 
mouth  of  the  Kasai  River,  370  miles  above 
the  mouth  of  the  Congo,  and  then  by  wire- 
less to  Stanley  Falls,  870  miles  above  the 
Kasai. 


ELECTRICITY  AS  FOOD:  MR. 
HOOVER  PLEASE  NOTE. 

M.  Bergonie,  the  eminent  French  doctor, 
has  solved  the  high  cost  of  living  by  means 
of  diathermy.  In  other  words,  he  claims 
to  have  made  electricity  take  the  place  of 


TELEPHONE  IN  COCOANUT 
STARTLES  NATIVES. 

Modern  home  comforts  are  not  exactly 
familiar  to  Sulu  Islanders,  according  to  a 
report  publisht  by  the  Society  for  Elec- 
trical Development. 


THE  MAN  WITH  THE  MAGNET. 

Almost,  if  not  equally,  as  famous  as  the 
immortal  "man  with  the  hoe"  is  the  "man 
with  the  magnet" — the  man  we  see  in  all 
of  the  leading  industrial  plants  now-a-days. 
The  illustration  shows  a  powerful  12-inch 
electro-magnet  handling  a  1,500  pound  steel 
billet  in  the  plant  of  the  Duplex  Metallic 
Co.,  Conshocken,  Pa.  It  lifts  the  billet  just 
as  easily  as  a  man  would  lift  a  25  pound 
sack  of  flour.  At  the  touch  of  a  switch 
the  magnet  loses  its  magic  power  and  the 
■billet  drops  or  lays  where  it  is.  Attached 
to  traveling  cranes,  the  amount  of  work 
one  of  these  electro-magnets  in  the  larger 
sizes  can  accomplish  in  one  day  is  quite 
astonishing.  They  will  unload  a  freight 
car  full  of  pig  iron  in  less  time  than  a 
gang  of  men  and  at  a  fraction  of  the  cost. 
The  larger  sizes  of  electro-magnets  are 
capable  of  lifting  single  pieces  weighing  as 
much  as  60,000  pounds,  or  30  tons.  Such 


From  the  Philippines  Comes  an  Interesting  Electrical  Stunt  That  Fooled  the  Islanders.  The 
Yankees  Simply  Dropt  a  Telephone  Receiver  in  a  Cocoanut  Shell,  Which  Hung  Outside  the 
Building.    When  the  Cocoanut  Started  to  "Talk" — Well,  Say. 


Here  We  Have  the  "Man  With  the  Magnet,"  Who  Is  Almost  as 
Famous  Nowadays  as  the  Immortal  "Man  With  the  Hoe."  The 
12-inch  Electro-Magnet  Is  Shown  Lifting  a  1,500-lb.  Steel  Billet. 


a  giant  electro-magnet  as  this  measures 
62J/i  inches  in  diameter,  consumes  72 
amperes  at  220  volts,  and  weighs  7,500 
pounds,  net. 


food.  Applications  of  the  electric  juice  will 
furnish  the  body  with  nourishment.  He  has 
tried  his  idea  on  a  man  weighing  only  110 
pounds,  who  had  not  been  receiving  suffi- 
cient nutrition.  In  a  short  time  this  man 
was  fat  and  sassy.  Electricity  did  it.  It 
furnishes  the  heat  for  the  body  which  is 
usually  furnished  by 
food. 

The  poor  man  who 
owns  an  eighty  horse- 
power Mercedes  and 
cannot  afford  to  buy 
food  and  gasoline 
both,  and  is  slowly 
starving  to  death,  can 
go  out  in  his  garage 
and  three  times  a 
day,  disconnecting  the 
wires  of  his  storage 
battery,  can  consume 
all  of  the  electricity 
that  he  needs.  This 
will  take  the  place  of 
breakfast,  dinner  and 
supper,  or  breakfast, 
luncheon  and  dinner, 
depending,  of  course, 
upon  the  man's  sta- 
tion in  life.  When 
an  automobile  party  is 
stranded  nineteen 
miles  from  a  garage 
all  of  the  members  of 
it  can  be  fed  from 
the  batteries  in  the 
car. 

Whole  families  may  be  fed  from  an  elec- 
tric lighting  chandelier  in  the  parlor  and 
this  will  save  the  trouble  of  cooking.  And 
then  electricity  will  not  smell  up  the  house 


"While  in  the  Government  employ  in 
the  Philippines,"  says  this  writer,  "I  was 
stationed  on  the  island  of  Pasilan,  which 
is  a  small  island  in  the  Sulu  Archipelago. 

"We  frequently  had  them  entertain  us 
with  their  native  dances,  and  in  turn  would 
fill  them  with  wonder  and  awe  with  a 
phonograph  which  we  had  in  our  outfit. 
We  found  it  necessary  to  put  up  a  tele- 
phone line  between  two  buildings  that  were 
a  little  distance  apart,  using  two  magneto 
sets.  One  day  I  found  a  rather  large 
cocoanut  under  a  tree  near  the  bamboo 
hut  we  were  living  in,  and  conceived  the 
idea  of  making  a  cocoanut  talk.  So  I 
emptied  its  contents  and  hung  it  on  the 
outside  of  the  house  opposite  the  phone, 
so  arranged  that  we  could  put  the  receiver 
thru  the  grass  wall  and  drop  it  into  the 
cocoanut. 

"We  invited  some  of  the  natives  to  see 
the  wonderful  cocoanut  that  we  could  make 
talk,  and  with  the  aid  of  an  interpreter 
at  the  other  phone  who  understood  their 
language,  we  had  a  lot  of  fun.  Some  of 
the  natives  were  so  frightened  they  left  the 
village.  Next  day  a  delegation  returned  and 
directed  us  to  destroy  the  talking  cocoa- 
nut,  under  penalty  of  immediate  attack. 
They  did  not  like  to  have  so  uncanny  a 
thing  around.  There  was  much  rejoicing 
when  we  consigned  it  to  the  flames. 

like  corned  beef  and  cabbage  does. 

However  pleasant  it  would  be  to  get  a 
breakfast  from  an  electric  belt  or  get  a 
ten-course  dinner  from  the  batteries  in  the 
telephone,  we  fear  there  is  a  catch  in  it 
somewhere  and  it  will  probably  be  some 
time  before  powerhouse  banquets  will  be- 
come a  reality. 


448 


THE  ELECTRICAL  EXPERIMENTER 


November,   1 9  \  7 


Historic  Electric  Apparatus 


By  H.  WINFIELD  SECOR, 

Assoc.  A.  I.  E.  E. 


THE  present  article  is  an  endeavor  to 
refresh  the  minds  of  our  electrical 
students  with  the  antecedents  of  the 
wonderful  present-day  electrical  in- 
ventions.   Like  every  invention  or 
science,  the  art  of  electricity  has  had  its 
full    share    of    struggling    inventors  and 
laugh-producing  inventions. 

The  early  inventions  in  electrical  science 
here  discust  are  not  necessarily  the  very 
first  effort  made  in  each  respective  line,  but 
are  those  which  are  given  credit  historically, 
being  the  fundamental  ones  from  which  all 
later  practical  applications 
developed. 

One  of   the   first  elec-  

trical  phenomenon  experi- 
mented with,  was  that  of 
static  electricity.  Fig.  1 
shows  the  first  static  ma- 
chine as  devised  by  Otto 
Von  Guericke,  of  Magde- 
•burg,  Germany,  in  the 
year  1630.  The  illustra- 
tion shows  Von  Guericke 
and  also  his  machine, 
which  consisted  of  a  globe 
of  sulfur  fixt  upon  a  ro- 

tatable  spindle  so  that  it  .  

could  be  revolved  rapidly 
by  means  of  a  crank. 
Powerful  static  electric  shocks  were  ob- 
tained from  this  relatively  crude  device 
by  pressing  against  the  surface  of  the  sul- 
fur ball  with  the  hand,  while  it  was  being- 
turned. 

The  Voltaic  pile  illustrated  in  Fig.  2 
was  invented  by  Alessandro  Volta  in  1775. 
This  device  was  the  first  to  produce  what  is 
properly  known  as  voltaic  (also  called  gal- 
vanic) electricity.  This  battery  was  made 
by  placing  a  pair  of  discs  of  zinc  and  copper 
in  contact  with  one  another,  then  laying  on 
the  copper  disc  a  piece  of  flannel  or  blotting 
paper,  moistened  with  brine ;  then  another 
pair  of  discs  of  zinc  and  copper,  etc.,  each 
pair  of  discs  in  the  pile  being  separated  by 
moist  conductor.  Such  a  pile,  if  com- 
posed of  a  number  of  such  pairs  of  discs 
will  produce  electricity  enough  to  give  quite 
a  perceptible  shock,  if  the  top  and  bottom 
disc  terminal  wires  be  touched  simultane- 
ously with  the  moist  fingers.  Volta  is  given 
credit  for  laying  the  foundation  of  all  pres- 
ent day  batteries. 

The  first  electric  telegraph  of  which 
we  have  historic  record,  and  also  that  on 
which  most  writers  and  authorities  agree, 
is  that  of  George  Louis  Le  Sage,  a  French- 
man residing  in  Geneva,  Switzerland,  and 
who  built  his  first  telegraph  in  1774.  The 
Le  Sage  telegraph  system  employed  24 
wires,  placed  in  a  trough  in  the  ground, 
the  wires  being  suitably  spaced  and  insu- 
lated by  means  of  glass  partitions  at  fre- 
quent intervals.  Each  wire  represented  a 
certain  letter  of  the  alphabet.  As  is  known, 
gold  leaf  is  extremely  sensitive  to  minute 
electric  impulses,  and  so  we  find  that  Le 
Sage  placed  a  small  piece  of  gold  leaf  at 
the  end  of  each  wire.  To  send  a  signal  over 
any  particular  wire  corresponding  to  a  cer- 
tain letter  of  the  alphabet,  a  small  static 
charge  was  sent  thru  the  wire  by  touching 
it  at  the  transmitting  station  with  a  glass 
rod  which  had  previously  been  electrically 
excited  by  rubbing  it  with  silk.  This  sys- 
tem was  rather  limited  in  its  application,  as 
it  is  very  difficult  to  insulate  a  static  charge 
for  any  great  distance. 

The  next  serious  form  of,  electric  tele- 
graph devised  was  that  of  Soemmering, 
bearing  the  date  of  1808,  Munich,  Germanv! 
This  is  the  machine  illustrated  in  Fisr.  3.  It 
operated   on   a  very  ingenious  principle; 


viz.,  that  of  the  electrolysis  of  water  by 
the  passage  of  an  electric  current  thru  it. 
This  inventor  used  a  wire  for  each  letter, 
the  same  as  Le  Sage,  and  to  send  a  signal 
over  any  certain  wire,  but  the  wire  in  this 
case  could  be  of  considerable  length.  With 
this  system  it  was  but  necessary  to  pass  a 
small  battery  current  thru  the  proper  wire, 
which  caused  the  water  in  the  indicating  de- 
vice at  the  opposite  end  of  the  line  to  be 
decomposed,  this  indication  being  evidenced 
by  the  production  of  a  large  amount  of 
(hydrogen)  gas  bubbles  in  the  water. 


In  the  present  article,  describing  historic  electric  apparatus,  you  will 
find  many  facts  not  generally  known.  For  instance,  did  you  know  that 
the  first  electric  telegraph  was  actually  worked  in  1774,  by  Le  Sage,  a 
Frenchman  residing  in  Geneva,  Switzerland? 

Did  you  know  that  incandescent  electric  lamps,  employing  a  carbon- 
ized paper  filament  burning  in  a  vacuum  were  successfully  constructed 
as  far  back  as  1845?  This  lamp  was  invented  by  a  Yankee — Mr.  Starr  of 
Cincinnati,  Ohio.  The  first  successful  arc  lamp  with  automatic  carbon 
feeding  mechanism  was  built  about  the  same  time,  by  an  Englishman 
named  Wright.   The  history  of  these  electric  inventions  is  a  real  romance. 


The  first  electric  motor  is  undoubtedly  of 
interest  to  every  electrician.  Early  in  the 
19th  century  a  number  of  philosophers  be- 
came much  interested  in  the  effect  of  elec- 
tric current  carrying  conductors,  especially 
in  their  reaction  when  placed  in  the  field  of 
a  magnet.  With  respect  to  the  first  electric 
motor  devised,  credit  is  invariably  given  to 
Michael  Faraday,  who  devised  the  first  elec- 
tro-magnetic rotation  apparatus  in  the  year 
1822.  Barlow  in  1823  produced  the  rotation 
of  a  star  wheel  placed  in  the  field  of  a  strong 
magnet  as  shown  in  Fig.  4.  These  devices 
were  very  crude  and  simple  however,  and 
developed  infinitesimal  power.  Undoubtedly 
the  first  electric  motor  employing  electro- 
magnets wound  with  many  turns  of  wire, 
and  also  comprising  a  motor  which  utilized 
both  permanent  steel  magnets  and  electro- 
magnets, was  that  perfected  by  Prof. 
Joseph  Henry,  of  Princeton  University,  in 
the  year  1831.  Henry  produced  recipro- 
cating motion  as  well  as  the  rotary  motion 
by  electro-magnetic  means.  Henry's  motor 
of  the  vintage  of  1831  is  also  shown  in  Fig. 
4.  This  was  the  forerunner  of  the  present- 
day  electric  motor  of  which  there  are  many 
hundred  thousands  in  use  in  all  parts  of  the 
world.  Henry's  device  interrupted  the  bat- 
tery current  by  its  oscillating  or  rotary  mo- 
tion in  an  intermittent  manner  in  either 
case.  It  is  interesting  to  note  that  Henry 
called  his  motor  a  "philosophical  toy."  In 
studying  the  history  of  electric  motors  and 
dynamos  it  is  well  to  keep  in  mind  this 
first  electro-magnetic  motor  of  Professor 
Henry's,  which  fact  will  be  further  touched 
upon  in  the  present  article,  as  it  had  a  very 
important  bearing  on  certain  other  inven- 
tions. 

The  dynamo,  which  produces  electricity 
by  rotating  an  inductor  or  series  of  induc- 
tors in  the  field  of  a  powerful  magnet,  was 
first  studied  on  the  basis  of  a  peculiar  phe- 
nomenon. The  first  experiment  in  this  field 
reverts  back  to  what  is  known  as  Arago's 
disc.  This  consisted  of  a  brass  or  copper 
disc  which,  when  rotated  at  considerable 
speed  and  placed  below  a  magnetized  com- 
pass needle,  caused  that  needle  to  be 
dragged  around.  These  "Arago's  rotations," 
as  they  were  called,  were  supposed  to  be 
some  kind  of  mysterious  magnetic  rotation, 
until  Faraday  proved  them  to  be  due  to  in- 


duction and  simply  obeying  a  basic  law  of 
electro-magnetism.  The  next  definite  step 
in  the  development  of  the  dynamo  as  a  pro- 
ducer of  electricity  by  electro-magnetic 
means  was  in  1831,  when  Faraday  made  his 
first  experiments  with  a  revolving  copper 
disc  placed  between  the  poles  of  a  very 
powerful  magnet.  In  some  of  these  experi- 
ments, a  copper  disc  was  allowed  to  dip  in 
a  trough  containing  mercury ;  the  electric- 
current  being  taken  from  the  axle  support- 
ing the  disc,  and  from  the  mercury  trough 
in  which  the  disc  dipt  as  it  was  rotated  by 
means  of  a  crank  handle. 
^ — About  a  year  later  Pixii 
 devised  an  electro-mag- 
netic dynamo  as  shown 
also  in  Fig.  5,  which  in- 
volved the  use  of  a  re- 
volving permanent  steel- 
magnet  placed  below  two 
iron  cores  containing  coils 
of  wire.  By  means  of 
driving  gears  and  a  handle 
as  shown  in  the  illustra- 
tion, Pixii  was  able  to  pro- 
duce quite  strong  alternat- 
ing currents  with  his  dy- 

  namo    as    the  permanent 

magnet  spun  around  be- 
low the  magnet  coils  at 

high  speed. 

The  trolley  car,  with  which  we  are  all 
familiar  today,  and  which  moreover  seems 
so  simple  that  it  would  almost  appear  to 
have  always  been  with  us,  instead  of  pass- 
ing thru  many  stages  of  evolution,  was  dis- 
tinctly an  American  invention.  Going  back 
to  the  work  of  Prof.  Joseph  Henry  and  the 
electric  motor,  it  is  recorded  that  Thomas 
Davenport,  a  New  England  philosopher 
who  was  residing  in  Vermont,  went  to  see 
one  of  Prof.  Henry's  powerful  electro-mag- 
nets in  operation  at  a  manufacturing  plant 
where  the  magnet  was  in  use  for  the  pur- 
pose of  removing  iron  from  clay  and  other 
materials.  This  was  about  the  year  1833, 
and  Davenport  was  much  imprest  by  the 
great  power  of  the  then  new  electro-mag- 
nets, one  of  which  he  saw  demonstrated  by 
lifting  a  heavy  steel  anvil  when  excited  by 
three  battery  cells. 

Davenport  did  much  thinking  on  this  sub 
ject  and  at  once  started  building  models  of. 
electric  motors,  and  he  is  given  credit  for 
producing  the  first  electric  railway  in  1835 
History  records  that  Davenport  actually 
made  over  one  hundred  models  of  electric 
motors  in  the  period  from  1835  to  1840 
These  included  motors  of  every  conceivable 
type  and  variety,  both  with  electro-magnets 
and  permanent  magnets.  He  exhibited  an 
excellent  model  of  his  proposed  electric  rail- 
way in  Boston  in  1840.  Davenport,  so  we 
learn,  was  not  an  educated  technician  or 
true  philosopher  of  the  college-bred  type, 
but  was  a  natural  born  genius,  and  it  is  said 
of  him  that  he  surely  realized  the  wonder- 
ful basic  principle  which  underlies  every 
electric  motor  and  dynamo  today ;  i.e.,  that 
to  obtain  the  maximum  and  most  satisfac- 
tory results,  there  shall  be  two  distinct  mag- 
netic fields  employed,  one  of  which  shall  be 
of  permanent  polarity,  and  the  other  of 
which  shall  be  of  constantly  changing 
polarity. 

The  first  incandescent  electric  lamp  has 
been  a  bone  of  contention  for  a  great  many 
years,  and  much  mystery  surrounds  the 
early  days  of  the  incandescent  lamp.  Most 
historical  electrical  treatises  give  credit  for 
the  first  incandescent  lamp  to  Sir  Hum- 
phrey Davy,  who  exhibited  this  type  of 
illuminant  (first  demonstration  in  1802)  in 
(Continued  on  page  499) 


November    19?  7  THE  ELECTRICAL  EXPERIMENTER  449 


HISTORIC  ELECTRIC  APPARATUS 


(For  descriptive  text  see  opposite' page.) 


450 


THE  ELECTRICAL  EXPERIMENTER 

The  Marvels  of  Radio-Activity 

By  JEROME  S.  MARCUS,  B.Sc.  (Ch.  E.) 
Part  III. 


November,  1917 


Emanations. 

THE  substances  Thorium,  Actinium, 
and  Radium  possess,  in  addition  to 
the  ray-giving  properties,  that  of 
emitting  continuously  a  radioactive 
gas  or  emanation.  These  emanations 
all  possess  the  property  of  ionizing  a  gas 
and,  if  sufficiently  intense,  of 
producing  marked  photograph- 
ic and  phosphorescent  action. 

The  activity  of  the  radio- 
active gases  is  not  permanent, 
but  disappears  according  to  a 
definite  law  with  time,  namely 
a  geometric  progression.  (See 
Fig.  1.)  The  emanations  are 
distinguished  by  the  different 
rates  of  losing  their  activity. 
The  length  of  time  necessary 
for  the  activity  of  a  given 
amount  of  substance  to  drop  to 
half  value  is  called  the  "pe- 
riod" of  the  substance.  The 
Actinium  emanation  lias  a  pe- 
riod of  only  ,  3.7  seconds, 
Thorium  emanation — 54  sec- 
onds, and  Radium  emanation — 
3.9  days. 

An   Actinium  compound 
wrapt    in   a    thin    paper  and 
placed  on  a  screen  of  phos- 
phorescent zinc  sulfid  will,  in 
a  dark  room,  show  the  phos- 
phorescence   surrounding  the 
active  body  on  all  sides.  A  puff 
of  air  will  remove  the  emana- 
tion and  the  glow  dies  out,  but 
fresh  emanation   is  given  off 
and  the  glow  reappears.  (Due  to  the  present 
high  price  of  rare  chemicals,  this  experi- 
ment will  prove  too  costly  for  the  average 
experimenter.) 

Radioactive  waters  derive  their  proper- 
ties from  the  emanation  held  by  them  in 
solution,  gathered  by  the  passing  of  the 
water  thru  and  over  rock  matter  contain- 
ing radioactive  minerals.  But  on  coming 
to  the  surface  the  emanation  is  released 
and  decays.  So  it  is  evident  that  the  "radi- 
um waters"  advertised  are  in  the  main  com- 
mon fakes,  and  the  only  way  to  drink  real 


radium  waters  and  to  derive  the  therapeutic 
values  is  to  get  it  at  the  spring. 

Emanations  are  similar  to  all  other  gases 
— they  can  be  transferred  by  gas  currents, 
and  can  be  separated  from  air  or  other 
gases  by  extreme  cold  and  condensation. 
Rutherford  and  Soddy  showed  that  under 


IT"*. 

3^  Wm- 


A  Piece  of 
Own  Rays. 


Pitchblende  from  St.  Joachmisthal   Photographed   By  Its 
The  Pitchblende  Was  Spread  Evenly  Over  Black,  Opaque 
Paper  Covering  the  Photographic  Plate. 


ordinary  conditions  the  temperature  of  con- 
densation of  Radium  emanation  is — 150  C. 
or  240  degrees  below  zero  Fahrenheit. 

Radioactive  Changes. 

As  has  been  said  before,  the  radioactive 
materials  in  giving  off  rays  change  into 
entirely  new  and  distinct  substances,  e.  g., 
emanation  results  from  the  element ;  an- 
other substance  results  from  the  emana- 
tion. While  in  the  majority  of  cases  the 
products  break  up  either  with  the  emission 
of  the  alpha  or  beta  particles,  some  "ray- 


less"  ones  have  been  found  by  scientists. 

These  different  products  decay  according 
to  their  periods,  but  are  constantly  being 
formed  by  the  next  lower  material,  hence 
an  equilibrium  will  be  obtained.  The  ef- 
fects generally  noted  in  the  study  of  radio- 
active materials  are  then,  the  combined 
effects  of  all  these  products  in 
an  equilibrium  of  activity. 

These  products  differ  phys- 
ically and  chemically  from  the 
parent  matter.  The  radiation 
is  due  to  the  atomic  structure, 
or  better  to  the  atoms  them- 
selves, as  the  most  powerful 
physical  and  chemical  agencies 
have  no  effect.  In  1903  Ruther- 
ford and  Soddy  put  forth  the 
following  simple  explanation : 
— The  atoms  of  the  radioactive 
matter  are  unstable,  and  each 
second  a  definite  fraction  of  the 
number  of  atoms  present 
breaks  up  with  explosive 
violence,  in  most  cases  ex- 
pelling an  a  or  /3  particle  with 
great  velocity.  As  an  illustra- 
tion, if  an  a  particle  is  ex- 
pelled during  the  explosion, 
the  resulting  atom  has  de- 
creased in  mass,  and  possesses 
different  physical  and  chemical 
properties  than  the  parent 
atom.  So  a  new  substance  has 
appeared  as  a  result.  Now, 
this  new  matter  is  itself  un- 
stable and  it  in  turn  breaks  up, 
the  process  going  thru  the 
series  until  a  stable  atom  (i.  e.,  one  stable 
to  our  conception  of  time),  is  reached. 

The  breaking-up  process  has  been  figured 
out  mathematically  and  reduced  to  a  law 
of  radioactive  change  which  is  applicable 
without  exception  to  all  radioactive  matter. 
It  appears  to  be  an  expression  of  the  law 
of  probability,  for  the  average  number 
breaking  up  per  second  is  proportional  to 
the  number  present. 

Looked  at  from  this  point  of  view,  the 
number  of  atoms  breaking  up  per  second 


November,  1917 


THE  ELECTRICAL  EXPERIMENTER 


451 


should  have  a  certain  average  value,  but 
the  number  per  second  should  vary  from 
second  to  second  within  certain  limits  ac- 


an  atom  which  breaks  up  on  the  expulsion 
of  an  alpha  particle.  The  residual  atom 
acquires  sufficient  velocity  due  to  the  shoot- 
ing out  of  the  particle  to 
escape  and  be  deposited 
on  bodies  in  the  near 
vicinity.  This  is  especial- 
ly marked  in  a  low  vacu- 
um. For  example,  Ac- 
tinium A,  deposits  Ac- 
tinium B,  by  recoil,  while 
the  recoil  of  Actinium  C 
from  Actinium  B  depos- 
its it.  So  the  three  can 
be  separated  and  ob- 
served. 

Boltwood,   in   his  in- 
vestigations, set  forth  a 
lot  of  evidence  to  show 
that  Radium  is  derived 
from   Ionium,  and  that 
Actinium    is    a  further 
member    of    the  series. 
This    makes    the  three 
groups  of  elements  mem- 
bers    of     one  family. 
Rutherford  explains  that 
in    some    part    of  the 
Representation  by  Wilson  of  the  Difference  Between  the  A-    breaking-up    there    is  a 
and  B-Rays  Very  Plainly  Shown.    In  the  Middle,  a  B-Ray  of   complex  .action  and  Ac- 
Extreme  Velocity  with  Very  Few  Electrons  Is  Seen.  tinium   comes   off   as  a 

branch.    There  is,  how- 


cording  to  the  law  of  probability.  This 
variation  in  the  number  of  atoms  breaking 
up  from  second  to  second  becomes  more 
marked  in  the  weakly  radioactive  matter, 
where  only  a  few  break  up  per  second. 

The  following  table  gives  the  products, 
the  rays  emitted,  and  their  periods : 


PRODUCT 
Actinium 
Radioactinum 
Actinium  X 
Actinium  Emanation 
Actinium  A 
Actinium  B 
Actinium  C 

Radium 

Radium  Emanation 
Radium  A 
Radium  B 
Radium  C 
Radium  D 
Radium  E 

Radium  F  (Polonium?) 
Radium  G  (Lead?) 


ever,  no  grounds  for  the  connection  of 
Thorium  to  the  other  groups. 


RAY  PERIOD 

Rayless 

•  a  +  /319.5  days 
a     11.8  days 
a       3.7  seconds 
0     36  minutes 
a       2.15  minutes 
g  -)-  T    5.1  minutes 

a  1760  years 

a  3.86  days 

a  3  minutes 

Q  26  minutes 

a  +  8  +  T  19  minutes 

0  17  years 

0  5  days 

a  140  days 


Thorium 
Thorium  1 

Mesothorium  (Thorium  2) 
Radiothorium 
Thorium  X 
Thorium  Emanation 
Thorium  A 
Thorium  B 
Thorium  C 
Thorium  D 

Uranium 
Uranium  X 
Ionium 
Radium  (?) 


—  About  1010  years 
Rayless    5.5  years 

0  -\-  r      6.2  hours 
a     737  days 
a        3.6  days 
a       54  seconds 
0       10.6  hours 
a       55  minutes 
a     Very  short  (?) 

0  +  r     3  minutes 


a     5xl09  years 
0  +  t  22  years 
a  ? 


Beta  ray;  f  =  Gamma 


*  a  =  Alpha  ray;  0 
ray. 

It  is  extremely  difficult  to  analyze  the 
change  and  distinguish  the  various  products. 
It  must  be  proven  that  the  new  substance 
has  distinctive  physical  and  chemical  prop- 
erties, and  that  the  substance  under  con- 
sideration came  from  the  one  preceding  it, 
and  breaks  up  into  the  one  following  it  in 
the  series.  In  general,  some  property,  either 
physical  or  chemical,  has  been  found  which 
allowed  the  material  to  be  separated  and 
removed,  and  then  studied  independently. 
In  some  cases  ordinary  chemical  means  are 
used,  in  others  electrolysis,  fractional  crys- 
tallization, differences  in  boiling  point,  etc. 

An  interesting  method  of  separation  is 
that  investigated  by  Russ,  Makower,  and 
Hahn,  and  which  depends  on  the  recoil  of 


An  Automatic  Atomizer  of  Radium  Emana- 
tion in  the  Form  of  an  Electric  Table  Foun- 
tain.  The  Emanation  Thrown  Off  in  a  Room 
Can  Be  Inhaled. 

Induced  Activity 

Curie  showed  that 
Radium  possest  an- 
other remarkable  prop- 
erty. The  surface  of  any 
body  placed  near  Radi- 
um, or  still  better,  im- 
mersed in  the  emanation, 
acquires  of  itself  a 
strange  activity.  The  au- 
thor has  seen  a  container 
of  Radium  salts  give  all 
the  experimental  results 
of  a  radioactive  sub- 
stance after  the  salts  had 
been  removed.  Like  the 
emanations,  this  induced 
activity  in  a  body  decays 
with  time,  but  at  quite  a 
different  rate  from  that 
of  the  emanation  itself. 

Rutherford  showed 
that  Thorium  possest 
a  like  property.  He 
showed  that  the  bodies 
made  active  behaved  as 
if  a  thin  film  of  intensely 


SIR  OLIVER  LODGE  ON  "ASTRON- 
OMY" VS.  ELECTRICAL  THEORY 
OF  MATTER. 

Sir  Oliver  Lodge,  in  a  recent  technical 
paper  on  this  subject,  gives  a  number  of 
arguments  which  are  summarized  as  fol- 
lows : 

1.  That  motion  of  matter  thru  ether 
has  a  definite  meaning,  apart  from  rela- 
tive motion  with  respect  to  other  matter. 

2.  That  an  extra  inertia  due  to  this 
motion  is  to  be  expected  at  high  speeds, 
in  accordance  with  the  FitzGerald-Lorentz 
contraction. 

3.  That  this  extra  or  high-speed  inertia 
is  not  part  of  the  mass,  but  is  dependent 
on  the  ether  and  hence  is  not  subject  to 
gravity. 

4.  That  from  this  reasonable  hypothesis 
astronomical  consequences  follow  which 
may  be  detected  when  cumulative. 

5.  That  under  certain  specified  condi- 
tions merely  a  small  change  in  eccentricity 
is  to  be  expected  as  the  chief  result,  in 
certain  others  an  apsidal  progress  or  re- 
gress is  to  be  expected. 

6.  That  the  outstanding  discrepancy  in 
the  theory  of  the  perihelion  of  Mercury 
would  be  accounted  for  by  attributing  a 
certain  value  to  a  component  of  the  true 
solar  motion  thru  the  ether  in  the  direc- 
tion of  the  planet's  aphelion  path. 

7.  That  using  this  value  for  the  solar- 
plus-stellar  drift,  viz.,  two  or  three  times 
the  earth's  orbital  velocity,  a  result  can  be 
obtained  for  the  perihelion  of  Mars,  sub- 
ject to  a  hypothesis  about  direction. 

8.  That  by  discussion  of  discordances 
in  the  elements  of  different  planets  an  es- 
timate may  be  formed  of  the  magnitude 
and  direction  of  the  locomotion  of  the 
solar  system  in  its  invariable  plane. 


active  matter  were  deposited  on  the  surface. 
The  active  matter  could  be  partly  removed 
by  rubbing,  and  could  be  dissolved  off  by 
strong  acids.  When  the  acid  was  evapo- 
rated the  active  matter  remained  behind. 

It  was  shown  that  induced  activity  is  due 
to  the  emanations,  and  could  not  be  pro- 
duced were  no  emanation  present.  The 
induced  activity  on  bodies  is  due  to  a  de- 
posit on  non-gaseous  matter  derived  from 
the  transformation  of  the  emanations,  viz., 
the  transformation  products  as  shown  in 
the  table  above.  Therefore,  each  emana- 
tion will  give  a  different  deposit  with  a 
different  rate  of  decay.  The  period  for 
{Continued  on  page  485) 


Representation    of    Electrons    After    Wilson.     The  Electrons, 
Which  Consist  Solely  of  Gamma  Rays,  Have  Been  Produced 
From  Secondary  Beta  Rays  After  Complete  Absorption  of  A- 
and  B-Rays. 


452 


THE  ELECTRICAL  EXPERIMENTER 


November,  1917 


177,000  C.  P.  Mercury  Vapor  Lamps  Light 

"Movie"  Studio 


On  a  large  stage,  the  cost  of  lighting  for 
taking  1,000  feet  of  film,  which  would  mean 
about  two  day's  complete  work  with  the 


and  farthest  from  the  camera,  has  three 
frames  (24  tubes),  the  second  row  four 
frames,  the  third  three  frames,  the  fourth 


The  Powerful  Battery  of  Mercury  Vapor  Lamps,  Aggregating  177,000  Candle-Power.  as  Used 
to  Illuminate  a  Modern  Moving-Picture  Studio  Stage.     Over  200  Mercury  Vapor  Tubes  Are 

Used  in  this  Installment. 


lamps  on  for  about  two  hours,  would 
amount  to  $7.50  for  current  and  $1.50  for 
maintenance,  or  a  total  of  $9  for  1,000  feet, 
whereas  the  entire  cost  of  the  film  may 
have  run  from  $1,000  to  $4,000.  depending 
on  the  subject.  In  other  words,  the  best 
lighting  can  be  obtained  on  the  average  for 
less  than  one-half  of  one  per  cent,  of  the 
entire  cost  of  the  film.  Considering  the 
fact  that  some  actors  are  paid  $1,000  a  week 
and  over  in  salaries,  or  about  $50  per  work- 
ing hour,  every  single  minute  of  their  time 
that  can  be  saved  by  proper  lighting  is  in- 
strumental in  reducing  the  total  cost  of  the 
film. 

Some  interesting  features  are  embodied 
in  the  recent  installation  of  a  complete  arti- 
ficial lighting  system  by  mercury  vapor 
lamps  in  the  new  studio  where  "Rothacker" 
films  are  made,  in  Chicago,  especially  in 
the  methods  used  for  control  and  handling 
of  the  lighting  equipment. 

The  overhead  structure  adopted  for  this 
purpose  consists  of  a  double-girder  crane, 
running  on  tracks  supported  by  the  side 
walls  of  the  studio  and  spanning  the  52- 
foot  width  of  the  building.  The  tvvo 
girders  of  the  crane  are  separated  26  feet 
but  are  rigidly  fastened  together  by  a  series 
of  I-beams,  parallel  to  the  length  of  the 
studio,  from  which  the  overhead  lighting 
equipment  depends.  The  whole  crane  sys- 
tem travels  on  four  flanged  wheels,  moved 
at  present  by  hand-operated  continuous 
chain  and  gear  mechanism,  altho  provision 
is  made  for  electrical  traverse. 

Overhead,  top  or  skylight  effect  is  ob- 
tained from  five  rows  or  "skylight  frames," 
each  frame  consisting  of  eight  50-inch 
automatic-starting  mercury-vapor  tubes 
with  porcelain-enameled  reflectors  to  direct 
the  illumination  downward.  The  back  row, 
that  is,  the  row  over  the  rear  of  the  set 


row  three  frames  (one  has  five  tubes  only) 
and  the  fifth  row  two  frames. 

These  frames  ordinarily  slant  away  from 
the  camera  and  toward  the  set,  forming  a 
practically  continuous  plane'  at  an  angle 
with  the  floor.  However,  they  are  not  sup- 
ported rigidly  in  this  position  and  may, 
by  a  simple  crank  and  cable  device  on  each 
row,  be  raised,  lowered  or  changed  in  angle 
with  respect  to  the  floor.  In  addition  to 
this  movement  all  rows  of  frames,  except- 
ing the  second,  may  be  moved  on  the  crane 
itself,  in  the  line  of  its  travel,  to  a  point 
where  either 
end  frame  of 
any  row  will 
assume  a  posi- 
tion past  the 
side  girder. 
This  is  neces- 
sary to  facili- 
tate photo- 
graphing  diag- 
onally across 
the  studio. 

Side  illumi- 
nation is  fur- 
nished by  lamps 
on  stands.  Four 
of  these  are 
e  q  u  i  p  t  with 
eight  50-inch 
mercury  -  vapor 
tubes  each, 
three  with  nine 
each  and  two 
with  four  each. 
The  entire 
studio  equip- 
ment consists  ot 
208  mercury-va- 
portubes,  aggre- 
gating 177,000 
candle-power. 


A  POWER  SUBMARINE  CABLE. 

A  power  cable  transmitting  power  from 
Sweden  to  Denmark  is  the  longest  subma- 
rine cable  of  its  kind,  having  regard  to  the 
pressure  at  which  the  transmission  takes 
place.  The  power  is  received  by  the  elec- 
tricity and  tramway  company  at  Hellerup, 
near  Copenhagen,  and  is  transmitted  by  the 
South  Sweden  Power  Company,  at  Malmo ; 
the  generating  power  station  is  on  the 
Lagan  River,  about  fifty  miles  northeast  of 
Helsingborg.  The  cable,  which  is  3.35  miles 
long,  is  of  the  three-conductor  type,  insu- 
lated with  impregnated  paper.  It  was  tested 
at  the  works  at  87,500  volts,  and  carries 
current  at  35,000  volts.  The  jointing  of 
lead-covered  paper-insulated  cables  at  sea 
is  not  at  all  a  simple  matter,  according  to 
The  Electrician,  and  all  sorts  of  precau- 
tions had  to  be  taken  both  with  regard  to 
regulating  the  movements  of  the  ship  and 
its  laying  machinery,  and  also  with  regard 
to  the  exclusion  of  moisture  from  the  joints. 
The  greatest  depth  at  which  a  joint  is  laid 
is  120  feet. 


AN  ELECTRIC  CRANE  AND  MAG- 
NET WITH  SWIVELING  DE- 
VICE. 

By  Frank  C.  Perkins. 

The  accompanying  illustration  shows  an 
electrically  operated  traveling  outdoor 
crane  with  a  clever  swiveling  device  equipt 
for  lifting  magnet  service  at  work  in  an 
Ohio  steel  plant.  This  electric  crane  has  a 
capacity  of  10  tons  and  a  span  measuring 
29  feet.  The  upper  lifting  beam  of  this 
crane  is  equipt  with  an  electric  motor,  which 
is  under  the  control  of  the  crane  operator, 
so  designed  as  to  swivel  the  lower  beam 
and  load.  In  order  to  prevent  the  upper 
beam  swaying  laterally  or  longitudinally, 
due  to  starting  and  stopping  the  traveling 
motions  of  the  crane,  or  rotationally  due  to 
swiveling  the  lower  beam,  a  special  arrange- 
ment of  ropes  has  been  adopted  for  the 
suspension  of  the  upper  beam. 

It  is  pointed  out  that  in  consequence  of 
these  arrangements  and  of  the  use  of  the 
gigantic  magnets,  it  has  been  found  pos- 
sible to  dispense  with  the  services  of  a 
ground  man,  all  functions  being  performed 
by  the  operator  in  the  crane  cage,  and  elec- 
tric power  is  employed  to  great  advantage 
not  only  for  the  operation  of  the  crane 
but  for  picking  up  the  iron  and  steel  ma- 
terial and  its  movement,  with  the  least  pos- 
sible manual  labor  and  expense. 


To  Reduce  to  a  Minimum  the  Cost  of  Labor  In  Handling  Steel  and  Iron 
Plates,  an  Ohio  Plant  Utilizes  Three  Large  Electro-Magnets  Suspended 
From  a  Swiveling  Beam  Carried  by  a  Traveling  Crane.    The  Plates 
Can  Be  Released  in  Any  Position. 


November,  1917 


THE  ELECTRICAL  EXPERIMENTER 


453 


Bucking  The  "Lodge  Goat"— Electricity 


TIME  was,  fellow  Shriners  and 
brother  Elks,  when  the  always 
mysterious  "degree  team"  thought 
they  had  performed  their  work  well 
and  effectively  if  they  succeeded 
in  scaring  the  candidate  out  of  about  seven 
years'  growth  by  causing  him  unexpec- 
tantly  to  fall  into  a  tub  full  of  cold  water. 
But  the  electrical  genius  has  become  legion. 
Wherefore  we  find  that  lodge  and  other 
secret  society  initiations  are  now  really 
electrifying  and  the  proud  candidate  is 
made  to  actually  "feel"  that  he  is  "warmly" 
welcome. 

The  harmless  and  extremely  amusing 
electrical  stunts  for 
such  festivities  here 
illustrated  were  cre- 
ated in  the  fertile 
brain  of  one  John  J. 
Odenwald.  He  has 
spent  much  time  in 
working  up  these 
stunts  for  the  use  of 
various  organizations 
and  one  or  more  of 
them  will  surely  prove 
welcome  to  any  de- 
gree team.  The  stunts 
are  easy  to  perform 
and  provide  a  max- 
imum of  clean  fun. 

Imagine  the  gasp 
of  astonishment  from 
the  candidate  when 
he  serves  the  punch 
by  special  request. 
"  'Tis  a  proud  mo- 
ment in  me  life,"  as 
Mr.  Dooley  would 
say,  when  Mr.  Can- 
didate steps  to  the 
punch  bowl.  Upon 
touching  the  ladle  he 
receives  a  lively  elec- 
trical jolt  which 
shows  him  that  the 
liquid  has  a  real 
"punch."  The  illustra- 
tion shows  how  this 
trick  is  readily  car- 
ried out  by  means  of 
a  small  or  igni- 

tion) spark  coil,  bat- 
tery and  push  button. 
Use  high  tension  rub- 
ber covered  cable  to 
connect  up  the  sec- 
ondary circuit,  and  if 
possible  do  not  cross 
these  cables,  as 
"leaks"  may  develop. 

Another  is  a  harm- 
less looking  rug  in 
which  are  woven  elec- 
trical wires  and  ter- 
minals secretly  con- 
nected to  a  high- 
tension  spark  coil 
which  makes  the  ini- 
tiate do  some  lively 
stepping  when  every- 
thing is  in  readiness. 

Then  there  is  the 
electrified  wheelbar- 
row on  which  the  candidate  is  brought  into 
the  presence  of  his  new  brethren.  On  ap- 
proaching, the  person  who  is  wheeling  the 
barrow  quietly  presses  a  secret  button  in 
one  of  the  handles  which  operates  a  six- 
inch  electric  bell  to  warn  everyone  to  clear 
the  path.  This  also  serves  to  direct  at- 
tention to  the  startling  and  "shocking" 
event  which  happens  when  another  secret 
button  is  prest  that  causes  the  candidate 
to  arise  with  great  alacrity,  due  to  some 
very  sudden  applications  of  high-tension 
charges  manifesting  themselves  in  the  seat 


of  the  barrow.  Another  device  is  a  pair  of 
Dutch  sabots,  or  wooden  shoes,  which  are 
very  harmless  looking  and  yet  when  worn 
cause  the  wearer  to  suddenly  become  a 
dancer  of  very  funny  jigs.  These  wooden 
shoes  are  easily  charged  by  placing  a  metal 
strip  inside  and  outside  of  the  sole  as  in- 
dicated. These  are  riveted  thru  the  sole 
and  made  as  inconspicuous  as  possible. 
The  inside  strip  should  be  covered  over 
with  thin  leather  or  paper.  Alternately 
charged  metal  strips  are  placed  under  a 
canvas  covering  on  the  floor.  Let  the 
candidate  do  a  few  steps — then  switch  on 
the  cm  rent  and  you  will  learn  some  brand 


And  who  doesn't  like  to  pose  as  a  regu- 
lar "strong  man"?  Everybody.  As  a  shin- 
ing light  in  the  initiation  festivities  we  have 
with  us  the  magic  weight — labeled  500  lbs., 
say.  The  candidate  is  introduced  to  the 
weight  and  told  he  surely  can  lift  it  as  it 
is  made  of  a  mystic  metal,  sent  from 
Hindustan.  To  his  surprise  he  can  lift  it; 
but,  zowie ! !  When  the  handle  travels  its 
full  length,  it  throws  in  a  spark  coil  which 
lightens  his  burden  at  once. 


INDIANA  UNIVERSITIES  TO 
TEACH  RADIO  COURSE. 

For  the  young  man  who  inhales  with 


THEPUNCHBOWL  WITH  /)  REM  PUNCH  /N  /T 


GONG 
SPARKCOIL  BUTTON 
BUTTON 


WIRES  TO 
/1ETAL  STRIPS 

INSIDE  WHEELBARnis) 

THE  INITIATION  WHEEL  BARROW 
FJR5T  IT  PINGS-THEN  IT  SING5-(  /J  REDHOT  TUNE) 


HIGH  TEHS/ON  CABLE 


EL  ECTR/C  CO/VTACTS 
I 


^ELECTRIC  ROPE 


TO  SPARK  COIL 


WIRES  OF  OPPOSITE 
POL  AR/TY  WOVEN  IN  MAT 


CANDIDATE  DANCING  ON  THE  ELECTRIFIED  MAT 


CHARGED  THIN  STRIPS 
UNDER  CARPET 


HIGH  TENSION 
CABLE 


TO  SPARK  COIL 

THE  ELECTRIC  SABOTS 


TWO  HANDLES  5TR0NG 

SPRINGS 

S^^EIBER 

INSULATION 

y 

HIGH  TENSIOHlj 


INSULATED 
CONTACTS, 


muLC 


CAE  IE 


GUIDE  ROD 


EVERY  CANDIDATE  IS  A  STRONG  E1AN -SURE  - 
UNTIL  THE  "JUICE" SUDDENLY  PROVES  THE  STRONGER 


Every  Lodge  and  "Secret  Order"  Man  Will  Find  These  "Electrical  Initiation  Stunts"  of  Timely  Interest.  They 
Are   All    Easy   of   Application   and    Harmless    in   Their   Effects.     The    Electric    Stunt    Can    Be    Worked  Where 

Clumsy    Mechanical   "Goats"  Would    Fail  Miserably. 


new  steps  that  would  astonish  even  Vernon 
Castle. 

Just  to  prove  that  the  candidate  is  of 
good  physique,  introduce  him  to  the  climb- 
ing rope,  upon  which  it  is  customary  to 
place  about  15  feet  or  so  above  the  floor 
a  fez  or  other  suitable  object,  which  the 
novice  is  expected  to  climb  to  and  bring 
down.  After  climbing  the  rope  some  four 
or  five  feet,  current  from  a  magneto  is 
suddenly  applied  to  hidden  terminals  in 
the  rope  which  makes  the  candidate  come 
down  with  considerable  speed. 


zest  the  tale  of  the  daring  exploits  of  the 
wireless  operators  on  the  trans-Atlantic 
liners  and  the  work  wireless  does  in  sav- 
ing ships  from  submarines  the  colleges  of 
Indiana  this  fall  have  opened  up  attractive 
courses.  Wireless  telegraphy  courses  Will 
be  offered  at  Indiana,  Purdue  and  De- 
Pauw  universities  and  all  young  men  and 
boys  are  permitted  to  enter.  The  an- 
nouncement was  made  today  by  State 
School  Superintendent  Horace  Ellis.  The 
work  is  a  part  of  the  war  vocational  edu- 
cation program. 


454 


THE  ELECTRICAL  EXPERIMENTER 


November,  1917 


The  Cause  and  Nature  of  Magnetic  Currents 

By  F.  F.  MACE,  Superintendent  of  Public  Schools,  Dallas,  Texas 


IN    two    previous    articles,  "Magneto- 
graphs''  and  "Currents  About  Mag- 
nets,"   having    proven    by  magneto- 
graphs   and   other   experiments  that 
there  are  actual  currents  surrounding 
and  entering  magnets  and  solenoids,  we 
may  now  take  up  the  cause  and  nature  of 
these  currents.     In  the  article  "Currents 


1 

It 

,  ■ JJ,,  „ 

^^^^^  ^ 

Fig.  6 

\  +  © 

wire  bearing 


Interesting  Chart  of  the  Motions  Followed 
By  a  Suspended  Magnetic  Body  Near  a 
Charged  Conductor;  the  Body  Moves  In- 
ward Toward  the  Wire  as  Well  as  For- 
ward, Thus  Proving  the  Existence  of 
Currents  Moving  Inward  and  Forward,  in 
the    Direction    of   the  Current. 


About  Magnets"  it  was  mentioned  that  logi- 
cally we  should  begin  with  an  experiment 
in  regard  to  currents  surrounding  a  charged 
wire.  We  return  now  to  this  experiment 
in  regard  to  currents  surrounding  a  charged 
wire,  where  we  should  logically  have  begun, 
and  study  the  origin  of  these  currents,  their 
nature,  the  creation  of  electro-magnets,  and 
the  logical  explanation  of  the  phenomena 
connected  with  magnetism. 

It  is  well  known  that  a 
current  is  to  a  small  degree 
a  magnet :  that  iron  filings 
will  cling  to  its  side.  But 
it  has  been  asserted  that 
the*  "lines  of  force"  of  the 
magnetic  field  surround- 
ing such  a  wire  are  con- 
centric circles.  That  under 
certain  conditions  they 
have  this  appearance,  that 
circular  lines  of  filings 
may  be  made  to  appear 
about  the  wire,  is  not  due 
to  any  real  circular  nature 
of  the  lines  of  force,  as 
this  circular  field  is  now 
understood,  but  to  other  «^^— 
causes.  The  real  cause  of 
this  circular  appearance  and  the  true  direc- 
tion of  these  lines  of  force — currents — will 
be  shown  in  the  following  experiment : 

Support  a  wire  in  a  horizontal  position 
and  pass  thru  it  a  heavy  current  of  elec- 
tricity. Suspend  a  small  piece  of  iron  wire 
or  a  small  iron  ball  by  a  thread  of  unspun 
silk  or  a  hair  near,  but  not  touching,  the 
charged  wire.    The  iron  will  not  only  be 


attracted  toward  the  wire,  but  it  will  also 
move  forward  in  the  direction  which  the 
current  in  the  wire  is  flowing.  Often  this 
motion  is  such  as  to  form  an  ellipse,  the 
longer  axis  of  which  points  diagonally  to 
the  wire  and  forward  in  the  direction  of 
the  current's  flow,  the  iron  returning  along 
the  outer  curve.  If  the  position  of  the 
thread  and  the  suspended  iron  be  changed 
along  the  wire  a  series  of  curves  will  be 
formed  as  shown  in  Figure  6.  This,  as  in 
the  case  of  magnets,  proves  the  existence 
of  currents  moving  inward  toward  the 
charged  wire  and  forward  in  the  direction 
of  the  current  flowing  in  the  wire  itself. 

That  these  are  actual  currents  is  again 
proven  by  the  photographic  plate.  Photo- 
graphic plates  exposed  above  or  about  such 
a  charged  wire  under  the  same  conditions 
used  to  produce  magneto-graphs  are  dark- 
ened everywhere  within  the  field,  the  degree 
of  darkening  shading  off  towards  the  edge 
of  the  field.  Owing  to  the  direction  of 
these  currents  it  is  difficult  to  produce  a 
clear  magneto-graph  (that  is,  clear  images 
of  objects  placed  upon  the  plate),  but  even 
this  has  been  accomplished  to  some  extent. 
Further  experiments  will  probably  give  bet- 
ter results. 

Not  only  can  the  existence  of  these  cur- 
rents be  further  proven,  but  it  can  be  shown 
that  these  currents  are  propagated  in  waves 
and  the  amplitude  of  these  waves  can  be 
measured.  Support  a  sheet  of  glass  or  paper 
horizontally  over  a  wire  and  sprinkle  upon 
it  fine  iron  filings  as  evenly  as  possible. 
When  an  electric  circuit  thru  the  wire  is 
alternately  closed  and  opened  by  means  of 
a  key,  the  filings  will  be  formed  into  nodes 
across  and  at  right  angles  to  the  wire  and 
the  current  in  the  wire.  It  should  be  espe- 
cially noted  here  that  these  nodes  form  at 
the  first  closing  of  the  circuit  and  that 
they  do  not  change  position  thereafter, 
merely  becoming  more  marked  with  suc- 
cessive alternations  by  the  collection  of 
more  of  the  filings.  The  appearance  of 
these  nodes  in  the  filings  is  shown  in  Fig- 
ure 7.  This  shows  that  the  current  in  the 
wire  passes  along  it  in  a  series  of  impulses, 
thus  producing  a  series  of  similar  impulses 
in  the  external  currents.  The  production 
of  these  external  currents  is  analogous,  of 
course,  to  the  production  of  currents  about 
any  moving  body  or  substance.  In  sound, 
when  we  see  nodes  formed  as  in  Figure  7, 
we  recognize  wave  motion  and  are  able  to 
measure  wave  lengths  by  the  distance  be- 
tween nodes.  In  this  case,  also,  we  recog- 
nise wave  motion  and  are  able  to  measure 


little  in  the  distance  from  node  to  node. 
As  a  node  indicates  half  a  wave  length,  the 
waves  passing  over  the  wire  are  approxi- 
mately twice  .5618  mm.  (i.e.,  10  mm.  di- 
vided by  17.8)  or  1.1236  mm.  in  length. 
Doubtless  more  accurate  results  than  this 
can  be  obtained  and  it  is  barely  possible 
that  the  wave  lengths  may  be  found  to  vary 


The  author  of  the  present  article  has,  to  many  minds,  opened  up  an 
entirely  new  field  of  experimentation  with  his  "magnetic  currents." 
Particularly  would  this  appear  to  be  the  case  in  the  previous  articles  in 
which  Mr.  Mace  showed  some  excellent  photographs  taken  by  what  he 
calls  "magnetic  currents"  and  which  he  produced  by  placing  a  magnet 
close  to  a  covered  photographic  plate  for  a  period  of  several  weeks  in 
total  darkness,  when  the  outlines  of  several  objects  lying  on  the  photo- 
graphic plate  were  actually  photographed  thereon. 

Many  years  ago  (1851),  however,  quite  similar  phenomena  to  these 
outlined  were  observed  and  explained  at  great  length  in  a  scientific  work 
by  Baron  Von  Reichenbach,  who  claimed  that  it  was  possible  to  "see" 
the  magnetic  force  about  magnets,  and  to  which  the  name  of  "odic 
flame"  was  given. 


the  amplitude.  It  is  somewhat  difficult  to 
arrive  at  an  exact  result  on  account  of  the 
irregularity  of  the  particles  of  the  iron 
filings  and  because  of  their  more  or  less 
uneven  distribution  in  sprinkling  them  upon 
the  surface ;  but  careful  and  repeated  meas- 
urements and  countings  show  that  these 
nodes  average  17.8  to  the  centimeter,  with 
the  current  used,  and  that  they  vary  but 


An  Experiment  Made  By  the  Author  With 
Iron  Filings  Sprinkled  on  a  Glass  Plate 
Placed  Over  a  Charged  Conductor,  Which 
Proved  That  "Wave  Motion"  Was  Pres- 
ent By  the  Formation  of  "Nodes." 


with  the  strength  of  the  current  and  the 
nature  of  the  conductor  used.  It  is  suffi- 
cient at  this  point  to  show  the  wave  nature 
of  the  current  in  the  surrounding  field  and 
the  approximate  wave  length.  This  wave 
motion,  this  alternate  impulse  or  impulses, 
readily  account  for  the  concentric  circles 
about  the  wire.  A  series  of  impulses  mov- 
ing upward  and  inward  and  repeated  at 
regular  intervals  and  at  the  same  location, 
these  currents  moving  upward  and  inward 
as  do  the  currents  about  the  wire,  would 
produce  exactly  this  result.  That  each  sepa- 
rate impulse  or  wave  has 
its  origin  at  an  equal  dis- 
tance from  the  wire  on  all 
sides  accounts  for  the  con- 
centric appearance  of  the 
field  about  the  wire  as  will 
be  seen  by  Figure  8,  where 
the  upward  currents  are 
shown  passing  thru  a  sheet 
covered  with  iron  filings. 
The  production  of  these 
inward  and  forward  cur- 
rents about  the  charged 
wire,  produced  by  the  cur- 
rent in  the  wire,  are  in 

  exact  accordance  with  our 

knowledge  of  the  effect  of 
a  moving  body,  such  as  a 
projectile  thru  the  air. 

With  the  direction  of  these  currents  in 
mind,  and  remembering  the  spiral  nature 
and  direction  of  the  currents  surrounding 
a  magnet,  see  how  exactly  these  accord 
with  the  action  of  a  magnetic  needle  placed 
in  the  magnetic  field  of  a  wire  bearing  a 
current  and  how  clearly  and  logically  it  ac- 
counts for  the  action  of  the  needle.  When 


November,  1917 


THE  ELECTRICAL  EXPERIMENTER 


455 


a  magnetic  needle  is  placed  within  the  in- 
fluence of  a  wire  bearing  a  current  of  elec- 
tricity upward,  the  needle  points  to  the 
north  when  on  the  east  side  of  the  wire,  to 
the  west  when  on  the  north  side  of  the  wire, 
to  the  south  when  on  the  west  side  of  the 
wire,  and  to  the  east  when  on  the  south 
side  of  the  wire.    In  the  first  position,  to 
the  east  of  the  wire,  with  its  center  at  the 
point  of  tangency  of  a  concentric  circle, 
the  currents  surrounding  the  magnet  on  the 
side  nearest  the  wire  will  be  moving  in  the 
same    direction    as    the    currents  drawn 
towards  the  wire  and  upward  as  shown  in 
Figure  9,  in  which  are  shown  the  currents 
moving  upward  and  toward  the  wire  and 
on  the  right,  or  east,  a  magnetic  needle  with 
its  south  pole  indicated  and  the  currents 
surrounding  it  moving  in  the  same  direc- 
tion as  the  currents  moving  toward  the 
wire.    At  the  left,  or  west,  of  the  same 
figure  is  a  needle  with  its  north  pole  point- 
ing south  showing  the  currents  about  it 
also  moving  in  the  same  direction  as  the 
currents  toward  the  wire.    In  both  cases 
there  are  four  conditions  tending  to  keep 
the  needle  in  this  position  with  its  center 
tangent  to  the  circle.    The  currents  on  the 
under  and  inner  side  of  the  magnet  will  be 
re-enforced  by  the  currents  moving  toward 
the  wire  and  these  currents  will  tend  as 
far  as  possible  to  set  themselves  in  parallel 
directions  and  these  forces  acting  upon  the 
equidistant  ends  of  the  needle  will  be  equal 
and  the  needle  will  be  in  equilibrium  as  a 
tangent  with  its  center  touching  the  circle. 
The  spiral  currents  emerging  from  the  cen- 
ter of  the  magnetic  needle  are  strongly 
drawn  into  the  currents  entering  the  wire 
and  thus  the  center  of  the  needle  becomes 
the  natural  center  of  equilibrium.   The  cur- 
rents about  the  magnet  on  the  lower  and 
inner  side  are  moving  in  the  same  direction 
as  the  currents  entering  the  wire  and  a  par- 
tial ether-vacuum  is  formed  and  the  tend- 
ency of  the  needle  is  toward  the  wire  but 
so  'long  as  the  ends  are  equidistant  the 
equilibrium  is  maintained  with  the  needle 
tangent  to  the  circle.    On  the  upper  and 
outward  side  of  the  needle  the  currents 
are  moving  counter  to  the  currents  enter- 
ing the  wire  and  a  condensation  is  set  up 
tending  to  force  the  needle  toward  the  wire 


4, 

Fig.  8 

© 

Diagram  Showing  How  the  "Wave  Mo- 
tion" About  a  Charged  Wire  Produces  Con- 
centric Rings  of  Force  on  a  Plate  Contain- 
ing Iron  Filings,  By  the  Upward  Movement 
of  the  Conductor  Currents. 


but  so  long  as  the  ends  of  the  needle  are 
equidistant  equilibrium  is  maintained  with 
the  needle  tangent  to  the  circle  with  its 
center  touching  the  circle.   Move  the  needle 


How  the  Author  Explains  the  Action  of  a, 
Magnetic  Needle  (Compass)  When  Placed} 
in  the  Field  of  a  Charged  Conductor.  1 


on  the  right  1  mm.  directly  north.  The 
equilibrium  is  at  once  destroyed.  The  cur- 
rents tending  to  re-enforce  each  other  and 
to  move  parallel  are  now  acting  upon  2 
mm.  more  at  the  north  end  of  the  needle 
than  at  the  south  end.  The  currents  at 
the  center  of  the  needle  are  further  from 
the  point  of  tangency  and  the  center  is 
drawn  toward  the  wire.  The  vacuum  on 
the  inner  side  of  the  needle  is  acting  upon 
2  mm.  more  of  the  north  end  of  the  needle 
than  upon  the  south  end,  the  condensations 
on  the  outer  side  of  the  needle  are  acting 
upon  2  mm.  more  of  the  north  end  of  the 
needle  than  on  the  south  end,  and  the  north 
pole  of  the  needle  is  deflected  to  the  west 
until  the  center  of  the  needle  again  be- 
comes the  point  of  tangency  and  equilibri- 
um is  restored.  The  same  condition  will 
prevail  as  the  needle  is  moved  along  until 
at  the  north  of  the  wire  the  needle  will 
point  to  the  west.  Continue,  and  at  the 
west  of  the  wire  the  needle  will  have  its 
north  pole  pointing  south,  as  shown  in  the 
figure.  The  needle  will  always  set  itself 
tangent  to  the  circle  at  its  center  point  so 
that  the  vacuums  and  condensations  at 
both  ends  will  be  equal,  so  that  the  cur- 
rents surrounding  the  wire  and  the  magnet 
will,  as  far  as  possible,  be  moving  in  parallel 
directions,  and  so  that  the  two  sets  of  cur- 
rents between  the  wire  and  the  magnet 
will  be  moving  in  the  same  direction  and 
re-enforce  each  other.  This  is  in  accord- 
ance with  all  known  laws  of  physics — it  is 
what  would  be  predicted  of  air  currents 
under  the  same  conditions. 

So  far  we  have  spoken  of  this  motion 
about  the  wire  and  the  magnet  merely  as 
"currents."  Now  let  us  consider  what  these 
currents  really  are.  It  has  heretofore  been 
considered  and  conceded  by  physicists  that 
the  "lines  of  force"  in  these  fields  are  ether 
effects;  that  they  are  "lines  of  tension," 
"lines  of  direction,"  etc.,  in  ether,  and  that 
the  waves  given  off  into  air  by  an  electric 
discharge  are  ether  waves.  A  magnet  works 
just  as  well  and  just  as  effectively  in  a 
vacuum  where  ether  is  the  only  substance 


present  as  it  does  under  other  conditions. 
Finally,  the  action  of  these  currents  on  a 
photographic  plate  in  the  production  of 
magneto-graphs  by  the  magnet  and  the 
charged  wire  prove  these  currents  to  be 
currents  of  ether. 

Granted,  that  magnets  owe  their  effects 
to  ether  currents  about  them,  and  there  can 
be  no  further  question  in  regard  to  this, 
how  simple  and  logical  becomes  the  action 
of  the  magnetic  needle,  the  creation  of 
electromagnets,  and  the  phenomena  of  mag- 
netic attraction  and  repulsion. 

If  two  solenoids  or  two  permanent  mag- 
nets be  placed  one  above  the  other  with 
their  north  poles  pointing  in  the  same  direc- 
tion, the  currents  on  the  upper  side  of  one 
and  the  currents  on  the  under  side  of  the 
other  will  be  moving  in  opposite  directions. 
These  currents  meeting  each  other  will 
form  condensations,  will  mutually  oppose 
each  other,  and  the  reaction  will  drive  the 
poles  apart.  This  action  will  continue  till 
the  north  pole  of  one  is  over  the  south  pole 
of  the  other,  in  which  position  the  currents 
at  both  poles  of  the  two  magnets  on  the 
upper  side  of  one  and  on  the  lower  side  of 
the  other  will  be  moving  in  the  same  direc- 
tion, the  currents  will  re-enforce  each 
other ;  the  tendency  will  be  to  set  them- 
selves parallel  to  each  other,  a  partial 
vacuum  will  be  formed  and  the  p  :les  will 
be  attracted  towards  each  other. 

Under  these  conditions  the  action  of  a 
magnetic  needle  in  pointing  to  the  poles 
of  the  earth  is  no  longer  mysterious.  An 
average  child  might  be  led  to  see  the  cause. 
The  earth  is  rotating  in  ether  from  west  to 
east.  This,  and  the  revolution  of  the  earth 
about  the  sun,  sets  up  ether  currents  mov- 
ing from  east  to  west  about  the  earth, 
just  as  a  ball  whirling  in  air  has  air  cur- 
rents about  it.  This,  as  with  the  currents 
about  an  electromagnet,  makes  the  north 
pole  of  the  earth  a  south  magnetic  pole. 
A  magnetized  needle  then  tends  to  turn  so 
that  its  north  magnetic  pole  points  to  the 
south  magnetic  pole  of  the  earth  as  ex- 
plained in  regard  to  two  magnets,  so  that 
the  currents  about  the  earth  and  the  cur- 
rents on  the  under  side  of  the  magnet  will 
(Continued  on  page  486) 


The    Well-known    Experiment   of   the  Re- 
volving Wire  Dipping  in  Mercury,  Is  Used 
to    Further   Prove    the   Author's   Case  of 
"Currents  About  Magnets." 


456 


THE  ELECTRICAL  EXPERIMENTER 


November,  1917 


WELDING  WITH  THE  ELECTRIC 
ARC. 

Reduced  to  its  simplest  terms,  the  elec- 
tric arc  is  a  gap  in  an  electric  circuit.  The 
current  "jumps"  or  "arcs"  across  this  gap. 


Complete  Electric  Arc  Welding  Outfit.  It  May  Be  Moved 
From  Job  to  Job  When  Desired.    Note  the  Glass  Shield 


Which  Operative  Uses 


to  Protect 
Glare. 


Eyes  From  Blinding 


It  does  this  against  great  resistance  be- 
cause electric  current  does  not  pass  easily 
thru  the  atmosphere.  Because  of  this  re- 
sistance great  heat  is  produced  and  the 
ends  of  the  gap  in  the  circuit  become  very 
hot. 

Boys  have  made  an  electric  arc  for  weld- 
ing purposes  by  simply  connecting  to  the 
leads  in  a  pair  of  lead  pencils  each  wire 
of  an  electric  circuit.  When  the  leads  are 
touched  and  drawn  apart  an  arc  is  formed 
and  heat  is  produced  which  is  great  enough 
to  melt  metals  with  which  it  comes  in  con- 
tact. In  actual  practise  this  process  is  of 
course  much  refined,  as  a  matter  of  fact 
the  metal  which  is  to  be  welded  usually 
forms  one  end  of  the  gap.  or  one  electrode, 
and  a  stick  of  carbon  or 
a  rod  of  metal  forms 
the  other  electrode. 

The  heat  produced 
by  the  electric  arc  has 
never  been  measured, 
but  it  is  variously 
estimated  at  a  tem- 
perature of  6.500  tc 
7,000  degrees  Fahren- 
heit, and  is  the  highest 
temperature  which  can 
be  produced  at  the 
present  time. 

The  principal  ad- 
vantage of  the  electric 
arc  for  welding  is  the 
fact  that  it  produces 
intense  heat  at  very 
low  cost.  Compared 
for  instance  with  the 
oxy-acetylene  torch, 
the  electric  arc  will 
produce  effective  weld- 
ing heat  at  from  ten  to 
thirty  per  cent  of  the 
cost  of  the  other 
method. 


The  electric  arc  may  be  used  for  weld- 
ing practically  all  metals.  There  are  sev- 
eral practical  difficulties,  however,  which 
are  always  encountered  in  welding  work. 
These  limit  the  use  of  the  process  for  com- 
mercial purposes  somewhat. 

The  first  difficulty  is  the  expansion  and 
contraction  which  results  from  heating  a 
certain  part  of  a  piece  of  metal  or  from 
adding  new  metal  in  any  part.  It  will 
be  readily  seen  for  instance  how  the  heat- 
ing of  the  rim  of  a  metal  wheel  and  the 
subsequent  cooling  of  that  part  would  set 
up  strains  in  different  parts  of  the  wheel. 
This  difficulty  can  be  overcome  by  differ- 
ent methods.  The  whole  piece  is  often 
heated  before  the  welding  operation  be- 
gins or  it  may  be  annealed  by  heating 
afterwards.  In  the  matter  of  expansion 
and  contraction  the  electric  arc  has  a  dis- 
tinct advantage  over  the  oxy-acetylene 
flame,  due  to  the  fact  that  the  intense  heat 
of  the  arc  is  confined  to  a  very  small  area. 
The  oxy-acetylene  flame  always  heats  up 
a  large  area  around  the  weld. 

The  second  difficulty  in  weld- 
ing is  due  to  the  formation  of 
oxids.  Metals  at  high  heat 
combine  with  oxygen,  the  oxids 
thus  formed  on  the  parts  of  the 
metal  to  be  welded  will  prevent 
the  metals  coming  in  intimate 
contact  and  a  perfect  weld  can- 
not result.  The  welded  surfaces, 
however,  may  be  kept  clean  by 
floating  the  oxid  on  top  of  the 
molten  metal. 

Let  us  say  that  the  arc  in  a 
given  welding  example  uses  150 
amperes  current,  the  voltage  of 
the  supply  line  is  250  volts,  and 
the  voltage  really  necessary  at 
the  arc  for  welding  purposes 
averages  25  volts.  Also  assume 
that  the  current  will  cost  2  cents  per  K.W.H. 

We  will  then  compare  the  cost  of  elec- 
tric power  first,  when  welding  with  simply 
a  resistance  in  the  circuit ;  second,  when 
welding  with   a  75  volt  constant  voltage 


AN  ELECTRIC  AUTO  INDICATOR 
YOU  CAN'T  MISS. 

A  New  York  inventor  has  recently  pat- 
ented a  novel  device  for  indicating  the  di- 
rection proposed  to  be  taken  by  moving 
automobiles. 

Two  lamp  bodies  are  fastened  in  the 
middle  of  the  rear  mud  guards.  Suitable 
bulbs  are  connected  with  storage  battery 
or  other  existing  power  source  and  may  be 


You  Can't  Miss  this  Electric  Auto  Indicator. 
The  Illuminated  Hand  at  Right  or  Left  In- 
dicates Which  Direction  the  Machine  Is  Go- 
ing to  Take.  Works  in  Daytime  as  Well  as 
Night. 

illuminated  by  a  mechanism  placed  on  the 
shaft  of  the  steering  wheel  or  near  the 
driver.  When  the  lamp  in  either  lamp  body 
is  lighted,  a  large  figure  of  a  hand  is  shown 
up  clearly.  This  figure  shows  as  distinctly 
in  the  sunlight  as  it  would  at  night.  The 
hand  points  the  way  the  car  is  going  to 
be  steered  or  driven. 

Transparency  glasses  are  furnished  in  the 
forward  sides  of  the  lamp  body  and  when 
illuminated  the  direction  in  which  the  car 
is  going  to  be  turned  can  be  seen  by  a  car 
being  driven  toward  it,  as  well  as  any  car 
approaching  from  the  rear. 

A  bell  situated  at  any  convenient  posi- 
tion on  the  car  is  so  arranged  that  it  rings 
at  the  time  bulb  lights  and  continues  till 
the  light  is  turned  off.— Allen  P.  Child. 


System 


Formula 


250  V. 

Motor 
with 
Motor 


i; 


with  resistance. 


generator, 
resistance . 
Generator 
average  25,  no 


75   Volts  Constant 


Variable 
resistance . 


Voltage, 


Amp.  X  Volts 
1000 

Amp.  X  Volts  \  1.25 
1000  ) 
oltsj 


1000 


Current 
in 
Arc 

Kilowatt 
hours  per 
hour  welding 

Cost  of 
Power  per  hour 
of  welding 

150  Amp. 

37.5 

75  cents 

150  Amp. 

14.06 

28  cents 

150  Amp. 

4.69 

9.4  cents 

motor-generator,  and  third,  when  welding 
with  a  25  volt  motor-generator. 

We  shall  then  have  the  above  figures. 


A  Good  Example  of  Welding  Rolled  Steel.  The  Rim  of  this  Motor  Truck  Wheel  Is 
Formed  by  Rolling  a  Steel  Plate  Into  Shape,  Welding  the  Two  Ends  Together.  The 
Illustration  Shows  It  Before  and  After  Finishing.  The  Metal  at  the  Weld  Was  Cut 
Down  Until  It  Was  No  Greater  In  Thickness  Than  That  in  the  Plate  and  Still  It  Was 
Sufficiently  Strong  for  this  Severe  Service.    Finished  Rim  at  Right. 


NEW  PHYSICO-CHEMICAL  INSTI- 
TUTE IN  JAPAN. 

Th  e  "Elektrotech- 
nische  Zeitschrift"  con- 
tains a  note  on  the  new 
physico  -  chemical  re- 
search institute  being 
establisht  in  Japan.  It 
is  stated  that  2,000,000 
yen  has  been  allotted 
and  that  the  buildings 
were  partially  com- 
pleted by  the  end  of 
1916.  Among  the  sub- 
jects to  be  dealt  with 
at  the  institution  are : 
Electrical  and  electro- 
chemical researches, 
testing  of  instruments 
and  thermometers,  re- 
search on  optical  glass, 
synthesis  of  colors,  rub- 
ber and  oil,  the  fixation 
of  atmospheric  nitro- 
gen, microscopy  of 
metals,  etc.  The  pro- 
gram als"o  provides  for 
a  systematic  study  of 
the  natural  resources  of 
Japan,  Korea,  Man- 
churia, etc. 


November,  1917 


THE  ELECTRICAL  EXPERIMENTER 


457 


PORTABLE    ELECTRIC  WELDER 
BONDS  TRACK  RAILS. 

In  order  to  provide  a  means  of  installing 
electrically-welded  bonds,  which  would  be 
within  the  economic  possibilities  of  every 


ELECTROLYTE  LEVEL  INDICAT- 
OR FOR  IGNITION  BATTERIES. 

Our  illustration  shows  a  new  "Battery 
Protector"  gage  and  its  connections  to  the 
storage  battery  of  an  automobile. 

The  dial  of  the  instru- 
ment shows  that  the  battery 
needs  water  which  means 
that  the  electrolyte  in  one  or 
more  of  the  jars  of  the  bat- 
tery has  evaporated  until  the 
level  of  the  fluid  is  ap- 
proaching the  low  danger 
point. 

When  all  of  the  jars  of 
the  battery  are  sufficiently 
filled  with  fluid,  the  instru- 
ment will  show  blank. 

Nearly  all  battery  trouble 
is    directly    traceable   to  a 
condition  in  which  the  fluid 
in  the  battery  has  been  per- 
mitted to  evaporate  without 
being    replenished,  thereby 
exriosincr  a  portion  of  the 
Welding  Trolley  Track  Bonds  With  An  Electric  Furnace  of   plates  and  resulting  in  se- 
Special  Design.    It  Works  Quickly  and  Is  Portable.    Time  Per   rious  d'ineer  to  the  battery 
Weld  is  About  One  Minute.  with  "Battery  Pro- 

tector"    installed    on  your 

railway,  however  small,  a  Cleveland,  Ohio,  car,  you  are  immediately  notified  in  event 
concern  has  developed  a  portable  welder.  the  evaporation  of  the  fluid  in  the  battery 
This  apparatus  is  extremely  simple,  con-  reduces  the  level  to  the  danger  point  and 
sisting  merely  of  a  resistance  element,  im  lead  of  taking  the  filler  cap  off  the 
weighing  about  200  lbs.,  and  an  electric  battery  every  few  days  to  determine 
furnace  weighing  65 
lbs.  The  function  of  the 
apparatus  is  to  make 
possible  the  utilization 
of  the  current  from 
the  trolley  for  welding: 
the  bonds  onto  the  rail 
with  the  smallest  pos- 
sible apparatus.  By  the 
use  of  this  outfit  an  elec- 
trically welded  bond  is 
obtained  with  a  contact 
having  an  initial  high 
conductivity,  and  one 
which  is  claimed  will 
not  depreciate  on  ac- 
count of  the  elements, 
etc.  In  obtaining  this 
union  between  the  bond 
and  the  rail,  neither  an 
arc  nor  flame  strikes  the 
bond  or  rail,  thus  avoid- 
ing the  danger  of  injury 
to  the  bond,  rail  and  eyes 
that  such  methods  are  li- 
able to  introduce.  In- 
stead, a  heated  block  of 
grafite  presses  against 
the  bond  terminal,  which  produces  a  true 
weld  and  which  is  accomplisht  with  neither 
injury  to  the  operator,  the  bond  or  the 
rail. 

The  apparatus  is  held  in  position  for 
installing  a  bond  by  a  yoke  which  sets 
over  the  head  of  the  rail  and  a  chain  and 
hook  fastened  to  the  opposite  rail.  This 
holds  it  in  a  tilted  position,  so  that  a  part 
of  its  weight  presses  the  bond. 

The  process  is  as  simple  as  the  appa- 
ratus. The  trolley  circuit  thru  the  re- 
sistance and  furnace  to  the  rail  is  com- 
pleted by  closing  the  200-ampere  circuit 
breaker  mounted  in  the  center  of  the 
rheostat  and  controlled  from  the  handle 
at  the  bottom.  The  regulation  of  the  weld- 
ing is  obtained  by  adjusting  the  position 
of  the  electrode  and  by  the  use  also  of 
five  points  on  the  rheostat  for  this  pur- 
pose. A  current  of  from  60  to  125  Amp. 
is  used  in  making  a  weld  and  a  separate 
weld  is  made  for  each  terminal  of  the 
bond.  The  time  required  per  weld  is  about 
one  minute. 


sirable  to  use  an  electrolyte  in  which 
both  the  tungsten  and  the  anodic  reaction 
products  are  most  soluble.  With  a  sodium 
hydroxid  solution  as  electrolyte,  mercury 
or  silver  may  be  used  as  positive  electrode 
against  tungsten  as  negative  electrode.  The 
emf.  of  such  a  combination  using  mercury 
is  0.49  volt,  with  silver  0.69  volt.  Prelimi- 
nary experiments  with  tungsten  both  as 
fused  slugs  and  as  metal  powder  were 
promising,  especially  those  with  the  latter. 
Another  series  of  experiments  was  made 
and  is  still  being  continued  on  the  use  of 
tungsten  in  standard  cells,  results  of  which 
will  be  announced  later. 


A    NOVEL  SELF-CONTAINED 
ELECTRIC-GAS  BRAZING  TORCH. 

Electrical  manufacturers  and  contractors 
with  small  or  medium-sized  shops  where 
comprest-air  equipment  is  not  installed 
often  are  at  a  loss  for  convenient  facilities 
for  brazing  small  pieces,  heating  melting 
pots,  annealing  and  hardening  small  tools, 
etc.  For  these  and  similar  purposes  there 
has  been  placed  on  the  market  the  compact 
combined  electric  and  gas  torch  here  illus- 
trated. The  outfit  consists  of  a  small  mo- 
tor-driven blower,  that  furnishes  the  air 
blast,  a  brazing  blow  pipe,  five  feet  each  of 
armored  air  hose  and  gas  hose,  and  a  five- 
foot  connecting  cord  with  feed-thru  switch 
and  attachment  plug.  The  motor  is  a  uni- 
versal machine  suitable  for  use  on  100- 
volt  direct  or  alternat- 
ing-current circuits.  The 
gas  supply  pipe  should 
be  at  least  one-half-inch 
size.  Using  standard  il- 
luminating gas  with  the 
outfit  it  is  possible  to 
obtain  a  temperature  of 
2,300  degrees  Fahren- 
heit, which  means  that 
extremely  rapid  work 
can  be  done.  The  gas 
and  air  supply  can  be 
readily  regulated  by 
means  of  the  cocks  in 
each  supply  hose.  The 
blower  is  powerful 
enough  to  supply  air  for 
four  burners. 


Every   Battery   User,  and   That   Includes   Most   Every   Autoist,    Knows   What  a 
Nuisance  It  Is  to  Keep  Tabs  on  the  Electrolyte  Level.   Here's  An  Instrument  That 
Indicates  Instantly  When  "Battery  Needs  Water." 


whether  or  not  there  is  sufficient  fluid  in  the 
jars,  you  simply  watch  the  gage  dial  and  as 
soon  as  the  fluid  level  is  lowered  (or  the 
battery  develops  a  leak  or  low  cell) 
you  are  advised. 

There  is  absolutely  no  chance 
of  the  device  failing  to  indicate 
the  low  fluid  level  in  the  battery  as 
the  device  works  on  a  closed  cir- 
cuit and  displays  its  warning  sig- 
nal as  soon  as  the  circuit  is  opened. 


Woody  Island,  near 
the  Alaskan  town  of 
Kodiak,  will  be  the  site 
of  the  big  radio  station 
the  Navy  Department  is 
about  to  establish  to 
connect  Alaska  with  the 
chain  of  wireless  stations  on  the  Lower 
Pacific  Coast.  This  will  insure  against  in- 
terruption of  communication. 


ELECTROLYTIC  BEHAVIOR 
OF  TUNGSTEN. 

Walter  E.  Koerner  has  carried 
out  extensive  experiments  and  re- 
search work  under  the  direction  of 
Dr.  C.  G.  Fink,  in  the  research  lab- 
oratory of  the  Edison  Lamp  Works 
at  Harrison,  N.  J.  He  recently  made 
public  the  results  of  his  investigation 
in  a  paper  read  before  the  American 
Electrochemical  Society.  An  in- 
teresting feature  of  the  paper  was 
that  regarding  the  use  of  tungsten 
in  cells.  In  this  connection  the 
author  states  that  for  the  construc- 
tion of  a  voltaic  cell  with  tungsten 
as  the  negative  electrode  it  is  de- 


New  Combination  Brazing  Torch,  Consisting  of  Gas 
Blow  Pipe  and  Electrically  Driven  Air  Blast.     It  Is 
Extremely  Compact  and  Needs  Only  to  Be  Connected 
to  Gas  Pipe  and  Light  Socket. 


458 


THE  ELECTRICAL  EXPERIMENTER 


November,  1917 


NEW  ELECTRIC  STOVE  AND 
STERILIZER. 

Perhaps  what  is  one  of  the  more  ad- 
vanced types  of  electric  stoves  is  now  being 
offered  on  the  market. 

A  distinct  innovation  is  the  structure  of 


Latest  Electric  Sterilizer  For  Dentists,  Phy- 
sicians,   Etc.,    the    Electric    Heater  Being 
Available  Whenever  Desired  as  a  Stove  or 
Toaster. 


the  stove,  it  being  made  in  a  new  way, 
very  light,  strong  and  durable.  It  has  all 
the  good  points  and  none  of  the  bad  ones. 
It  can  cook,  broil,  toast  and  do  a  number 
of  other  things  as  a  much  needed  con- 
venience in  the  home,  and  is  also  adapted 
to  laboratory  and  sickroom  with  its  steriliz- 
ing equipment.  With  the  pans  as  shown 
in  the  photo  are  furnished  racks  so  that 
medical  instruments,  etc.,  can  be  placed  in 
the  same  for  thoro  sterilizing. 

With  its  number  of  good  features  and 
multifarious  service  delivered,  it  should 
find  many  friends. 


A  VERTICAL  TELEGRAPH  SPEED 
KEY. 

Herewith  is  shown  a  new  vertical  tele- 
graph speed  key.  The  vertical  key  com- 
bines in  one  stroke  extreme  simplicity,  ef- 
ficiency, light  weight,  (one  and  one-half 
pounds)  and  it  produces  a  very  superior 
quality  of  full,  solid,  clean-cut  dots.  In 
addition  may  be  mentioned  the  fact  that 
with  this  new  instrument  it  is  next  to  im- 
possible to  run  dots  and  dashes  together. 

It  represents  an  improved  type- of  single 
contact  instrument  and  it  is  so  extremely 
simple  that  it  reduces  repairs,  adjustments 
and  replacements  to  a  minimum.  The  key 
has  a  remarkably  easy  touch.  Moreover 
it  is  unnecessary  to  change  any  adjust- 
ments about  the  machine  except  to  slide 
the  speed  weight  up  or  down  when  it  is 
desired  to  send  faster  or  slower  or  to 
adjust  the  tension    springs    so    that  the 


Something    New    in    Speed    Keys  for 
Radio   and   Telegraph   Operators.  It 
Sets  in  a  Vertical  Position,  Being  Held 
Upright  by  a  Substantial  Base. 


"touch"  of  the  key  lever  feels  best.  And 
you  can,  of  course,  regulate  the  lightness 
or  heaviness  of  dots  by  turning  the  contact 


screw  in  or  out — just  a  little  at  a  time — 
until  the  dots  appear  to  be  solid  and  clear. 
Otherwise,  there  are  no  adjustments  to  be 
made. 


A  REMARKABLE  ALUMINUM 
SOLDER. 

Soldering  aluminum  parts  to  one  another 
or  to  other  metals  has  always  proven  a  very 
difficult  proposition,  and  this  problem  has 
become  of  extremely  vital  importance  of 
late  owing  to  the  fact  that  many  aeroplane 
parts  are  made  of  this  peculiar  metal  which 
refuses  to  unite  with  any  ordinary  metal 
under  the  usual  soldering  and  brazing  con- 
ditions, owing  to  the  oxid  which  forms 
very  quickly  on  the  surface  of  the  alumi- 
num, as  soon  as  it  is  cleaned  preparatory  to 
making  a  joint. 

It  remained  for  Dr.  O.  F.  Reinhold,  of 

■!  r  :'H  :r  .1   ,  i.  :  ;       1  i„ \';'!. 

J  ALL   ABOARD   FOR    THE   DE- ( 
CEMBER  "E.E." 

B  The  Xmas  number  of  The  Elec-  jjg 
H§  trical  Experimenter  will  fairly  teem  g 
g  with  good  things.  It  will  contain  g 
gg  articles  of  interest  to  every  man,  wo-  ^ 
g  man  and  child — to  use  the  language  g 
M  of  the  "Big  Show"  barkers.  There  g 
H  will  be  special  feature  contributions  J 
Hi  from  well-known  zvriters  as  well  as  =. 
jj  many  new  ones.  If  you  want  to  know  |] 
g  what  to  buy  or  what  to  make  for  j|| 
g  Xmas,  then  don't  fail  to  read  the  j|| 
U  "December"  issue.  Among  other  fea-  j| 
H  ture  articles  are  the  following: 
m  "A  New  Electric  Bomb  Dropper  M 
g  For  Aeroplanes,"  by  F.  R.  Lewis,  j§j 
g  Military  Expert. 

^  "Locating  Submarines  by  Radio  g 
!g  Waves — A  Tested  Scheme,"  by  Leon  I| 
HI  W .  Bishop,  One  of  Edison's  Electrical  §J 
g  Experts. 

g  "The  Aurora  Borealis;  Its  Effects  Jj 
g  on  Telegraph  and  Cable  Lines,"  §j| 
B  Some  facts  on  this  remarkable  phe-  j] 
jl  nomenon.  ig 
g  "How  to  Use  High  Frequency  Cur-  g 
H  rents  in  the  Treatment  of  Disease,"  g 
g  by  Dr.  Frederick  Finch  Strong,  M.D.  g 
jjj  "The  Marvels  of  Radio-Activity ," —  jj| 
=  Part   IV.,    by   Jerome    S.    Marcus,  m 

§g  "A  Revolving  Electric  Xmas  Tree —  a 
g  How  to  Make  It,"  by  John  T.  Dwyer.  B 
g  "The  Mysterious  V oice" — A  Clever  K 
a  Home-made  Electrical  Illusion,  by  C.  H 
j[  A.  Oldroyd. 

|§  "The  Audion  vs.  the  Edison  Effect,"  S 
g  by  George  Holmes.  §| 
S  "Radio  Transmitting  Inductances"  |§j 
jj  — 5th  paper  of  "How  and  Why  of  M 
U  Radio  Apparatus"  Series. 
§H  A  Funny  Electrical  Story — "Telling  j§ 
g  Time  by  the  Stars,"  by  Thomas  Reed.  || 
g  "Experimental  Physics" — Lesson  10  Jj 
gj  — by  John  J.  Furia,  A.B.,  M.A. 

T  ; 

New  Jersey,  to  invent  a  really  successful 
aluminum  solder  which  most  important  of 
all,  makes  a  joint  which  is  every  bit  as 
strong  and  generally  stronger  than  the 
metal  itself,  which  it  unites.  No  flux  is 
necessary  with  this  solder,  and  it  can  be 
melted  in  the  ordinary  Bunsen  flame. 

The  accompanying  photograph  shows 
several  samples  of  the  work  which  can  be 
done  quickly  and  without  the  least  trouble 
or  preparation  of  the  pieces,  and  all  of 
which  specimens  were  prepared  before  the 
Editors  by  the  inventor. 

Specimen  No.  1  at  the  left  shows  how 
a  piece  of  aluminum,  copper  or  brass  wire 
can  be  united  to  a  piece  of  aluminum  sheet 
so  as  to  form  a  solid  connection,  producing 
in  this  way  an  extremely  serviceable  elec- 


trode for  use  in  electrolytic  rectifiers  or 
electrolytic  chemical  determination  appara- 
tus. 

Specimen  No.  2  shows  several  wires 
twisted  tightly  together,  but  without  any 
cleaning  at  all  and  which  were  firmly 
soldered  in  a  minute's  time  with  this  new 


Some  Specimens  of  the  Work  Accomplisht 
by  New  Aluminum  Solder.    The  Joint  Is  as 
Strong  as  the  Stock. 


aluminum  solder,  the  solder  running  thru 
between  the  wires  and  making  a  first  class 
joint  in  every  particular. 

Specimen  No.  4  is  also  a  wire  joint  made 
with  this  solder.  No.  3  shows  a  small 
square  piece  of  aluminum  sheet  soldered 
to  a  similar  piece  at  right  angles.  Not 
only  was  this  joint  very  solid,  permitting 
one  to  bend  the  aluminum  to  any  degree 
without  showing  the  least  strain  at  the 
joint,  but  once  the  top  wing  shown  was 
soldered  on  and  "set,"  it  was  then  possible 
to  solder  another  piece  on  the  opposite  side 
of  the  longitudinal  strip  without  loosening 
the  solder  at  the  first  joint— a  truly  remark- 
able characteristic  of  this  unique  soldering 
and  welding  preparation  which  occupied 
eighteen  years  of  the  inventor's  life  in  its 
solution. 

Figure  5  shows  one  of  the  most  novel 
applications  of  this  aluminum  solder  which 
one  can  imagine,  viz.,  that  of  causing  ordi- 
nary wire  solder  to  flow  and  securely  take 
hold  on  a  piece  of  aluminum  sheet.  The 
inventor  has  outlined  a  possible  and  very 
radical  idea  in  this  direction  with  reference 
to  storage  battery  construction.  He  pro- 
poses that  where  a  light  weight  storage 
battery  is  desired,  that  the  base  structure  of 
the  plates  be  made  of  aluminum  and  then 
coated  with  lead  by  means  of  his  new 
solder.  The  inventor  also  claims  that  his 
solder  changes  to  aluminum  itself. 


ELECTRIC  LIGHT  FOR  THE  SEW- 
ING MACHINE. 

The  adjustable  light  fixture  here  illus- 
trated provides  a  perfect  and  directly  ap- 
plied working  light.  By  so  doing  they  in- 
crease the  efficiency  of  the  operator.  By 
their  use  all  machines  can  be  lighted  to 
save  current  and  to  prevent  eyesight  trou- 
bles, the  makers  state. 


Investigation  Has  Shown  That  About  $40,- 
000,000  Is  Lost  Annually  By  all  Manufac- 
turers, in  the  United  States,  Thru  Improper 
Lighting,  and  That  the  Clothing  Trades 
Bear  Their  Share.  Here's  One  Answer  to 
the  Problem. 

The  lamp  can  be  placed  instantly  in  any 
desired  position  or  as  quickly  moved  out  of 
the  way. 


November,  1917 


THE  ELECTRICAL  EXPERIMENTER 


459 


Action  at  a  Distance  as  Exhibited  in  Selenium  Crystals 

By  PROFESSOR  F.  C.  BROWN,  PH.  D.*    STATE  UNIVERSITY  OF  IOWA 


jk  CTION    at   a   distance   lias  puzzled 
f\        physicists  and  philosophers  alike 
/  \       for  centuries.   By  what  means  can 
■fr  the  Sun  act  on  the  earth  to  heat  it, 

or  by  what  mechanism  can  the 
Sun  act  on  the  earth  so  as  to  be  constantly 


Fig.  1.    A  Few  Specimens  of  Extra  Sensitive 
Selenium  Crystals  Used  by  Professor  Brown 
in   His  Researches  on  the  Electrical  Action 
Occurring   in   This  Substance. 

pulling  the  latter  away  from  a  rectilinear 
path?  Or  how  can  the  earth  continually 
accelerate  the  moon  toward  the  earth  ?  We 
have  had  to  be  satisfied  in  these  latter  cases 
with  the  knowledge  that  the  mutual  attrac- 
tions between  these  planes  are  in  accord 
with  the  law  of  gravitation.  But  no  physicist 
even  thinks  he  knows  what  gravitation  really 
is.  Generally  we  think  that  heat  on  the  Sun 
is  a  molecular  motion,  a  part  of  which  is 
transmitted  to  the  earth  by  consequent  waves 
set  up  in  a  hypothetical  medium,  the  ether. 
But  grant  the  necessity  of  this  medium,  who 
knows  how  these  waves  are  set  up  by  vibra- 
ting electrons  or  molecules  !  It  would  be  out 
of  place  here  to  discuss  all  the  difficulties 
that  this  ether  has  plunged  us  into.  Primarily 
this  ether  was  and  is  required  to  explain 
radiation  and  gravitation  at  a  distance. 

How  can  two  charged  pith  balls  which 
are  disconnected,  repel  each  other.  There 
are  just  two  answers  possible  apparently, 


Theoretical  Electric  Circuit  Devised  by  Au- 
thor to  Show  That  Changes  in  Resistance, 
Etc.,  of  Single  Conductor  Extension  at  B 
Will  Not  Affect  Current  in  Closed  Battery 
Circuit. 

one  is  that  some  medium  surrounding  one 
ball  is  set  in  some  state  of  stress  or  agita- 

*  Paper  specially  written  for  The  Electrical 
Experimenter. 


tion  which  reacts  on  the  second  pith  ball. 
The  other  explanation  is  that  the  one  pith 
ball  acts  at  a  distance  when  there  exists  a 
charged  body  at  the  distant  point.  The 
action  is  usually  supposed  to  be  trans- 
mitted by  some  method  not  thoroly  under- 
stood;  something  like  mental  telepathy  per- 
haps. Similarly  two  magnetic  poles  act  on 
each  other  at  a  distance  as  will  also  a  cur- 
rent of  electricity  act  on  a  distant  magnet. 

Action  at  a  distance  in  matter  is  quite  a 
different  phenomenon,  because  it  is  easy  to 
imagine  almost  any  desired  mechanism  in 
matter  and  because  we  have  become  fami- 
liar with  certain  transmitted  effects  in  mat- 
ter. Thus  an  earthquake  may  effect  a 
seismograph  on  the  opposite  side  of  the 
earth,  by  a  wave  sent  thru  or  around  the 
earth  crust.  A  bar  of  iron  if  heated  at  one 
end  will,  after  a  time,  become  hot  at  a 
distant  point,  by  the  well  known  process 
of  conduction  thru  molecular  motion.  If 
a  copper  wire  is  supplied  with  an  excess  of 
electrons  at  one  end  or  merely  acted  on 
by  electromagnetic  forces,  there  will  be 
manifest  certain  electrical  changes  at  the 
opposite  end. 

But  in  the  instances  above  the  transmis- 
sion is  relatively  slow  compared  with  light 
and  gravity.  There  is  manifest  in  selenium 
crystals  an  action  that  seems  to  be  trans- 
mitted much  more  rapidly  than  other  ac- 
tions in  matter  mentioned  above.  Some  of 
these  selenium  crystals  are  reproduced  in 

Imagine  an  electric  circuit  connecting 
New  York  and  Brooklyn  with  one  wire 
forming  a  part  of  the  circuit  projecting  into 
Jersey  City  as  shown  in  Fig.  2. 

Now  it  is  perfectly  well  understood  that 
if  the  physical  conditions  surrounding  the 
wire  between  the  points  A  and  B  are 
altered,  the  resistance  and  consequently  the 
current  may  be  altered,  e.g.,  if  the  temper- 
ature rises  in  the  region  AB  the  resistance 
will  rise.  But  the  part  of  the  wire  projecting 
out  into  Jersey  City,  no  matter  how  much  it 
might  be  heated,  would  exhibit  no  change 
of  resistance,  beyond  the  region  AB. 

Now  if  we  imagine  the  wire  projecting 
thru  AB  to  be  replaced  by  a  metallic  selen- 
ium crystal  of  the  hexagonal  system,  we 
have  an  entirely  new  situation.  Consider 
the  circuit  shown  in  Fig.  2  or  Fig.  3.  A 
selenium  crystal  whose  length  is  about  100 
times  its  diameter,  has  one  end  clamped 
between  electrodes  in  such  a  manner  that 
the  electric  circuit  is  completed.  Now  if  a 
narrow  pencil  of  light  falls  on  the  part  of 
the  crystal  between  the  electrodes,  the  con- 
ductivity of  the  crystal  is  altered ;  most  of 
the  change  taking  place  within  .01  second. 
This  has  been  known  for  some  time.  How- 
ever, if  the  same  pencil  of  light  falls  any- 
where along  the  crystal,  the  change  of  con- 
ductivity between  the  electrodes  is  almost 
as  great  as  if  the  light  impinged  there. 
Moreover  the  change  of  conductivity  takes 
place  just  as  rapidly  when  the  illumination 
is  at  one  end  of  the  crystal  as  at  the  other, 
so  far  as  measurement  can  determine.  In 
other  words  the  action  of  light  on  the  crys- 
tal at  O  is  transmitted  to  P  without  any 
apparent  lapse  of  time.  At  least  the  lapse 
of  time  is  less  than  .01  second.  The  con- 
ductivity itself  takes  place  only  between  the 
electrodes  and  not  around  the  crystal  as  is 
proved  by  the  fact  that  no  alteration  of 
the  conductivity  occurs  by  breaking  off  the 
crystal  at  any  point  beyond  the  electrode 
contacts.  The  fact  that  the  transmission  of 
the  light  action  takes  place  in  less  than  one 
hundredth  part  of  a  second,  is  ample  proof 
that  the  transmission  is  not  of  the  nature  of 
a  heat  wave. 

A  New  Property  in  Matter 

Thus  we  have  found  a  new  property  in 


matter,  viz.,  the  illumination  of  matter  at 
one  point  and  consequent  action  taking 
place  at  a  distant  point.  The  magnitude  of 
the  distance  is  probably  limited  only  by  the 
length  of  the  crystal.    Thus  far  this  limita- 


Cross-sect/on  of  a 
hexagono/ 'se/emam 
crys/e/ 


rig.  4 


iie/ogono/  crystal 
space  /a/Oce 


fig.S 
h'3.7-  /o'"cm 


X-Ray  Analysis  Has  Shown  That  the  Sele- 
nium Atoms  Are  Situated  at  the  Corners  of 
Triangles,  in  Such  a  Manner  as  to  Form 
Hexagons.  The  Distance  Between  Atomic 
Centers  Is  of  Course  Extremely  Small. 

tion  has  been  about  15  millimeters.  The 
manner  of  transmission  is  just  about  as 
much  a  mystery  as  the  transmission  of  the 
force  action  between  the  Sun  and  Earth. 

An  X-ray  analysis  shows  the  selenium 
atoms  to  be  placed  at  the  corners  of  tri- 
angles in  such  a  manner  as  to  form  hex- 
agons. The  distance  between  the  atomic 
centers  as  shown  in  Fig.  4  is  3.69  X  10— 3  cm, 
when  measured  perpendicular  to  a  regular 
surface  running  parallel  to  the  principal 
axis.  These  hexagonal  plates  are  fitted  one 
against  the  other  lengthwise  so  as  to  build 
up  an  acicular  hexagonal  crystal  such  as 
shown  in  Fig.  5.  The  distance  between 
these  plates  as  shown  by  the  X-ray  spec- 
trum is  3.7  X  10"8  cm.  or  .037  millionths  of 
a  centimeter.  From  this  data  and  the 
knowledge  of  the  density  and  atomic  weight 
of   selenium  crystals,   it  is  very  easy  to 


If  a  Narrow  Pencil  of  Light  Falls  on  a  Sele- 
nium Crystal  at  O,  It  Acts  in  the  Same  Space 
of  Time  as  If  the  Light  Acted  on  the  Point  P. 
Truly,  Action  at  a  Distance. 

show  that  two  atoms  of  selenium  are  placed 
at  every  point  in  the  space  lattice  compos- 
ing the  crystal. 

The  light  might  produce  a  vibration  of 
the  selenium  molecules  or  the  planes  of 
molecules  and  then  these  planes  of  mole- 
cules would  produce  motion  in  the  next 
neighboring  planes  and  so  on  until  the 
planes  all  along  the  crystal  were  in  vibra- 
tion. In  this  case  the  vibration  would  be 
{Continued  on  page  489) 


460 


THE  ELECTRICAL  EXPERIMENTER 


November,  1917 


Experimental  Physics 

By 

JOHN  J.  FURIA,  A.  B.,  M.  A.  (Columbia  University) 


LESSON  9. 

Light  (Continued). 

HE  second  and  more  important  dif- 
ficulty in  the  way  of  the .  Wave 
Theory  of  light  was  that  it  failed  to 
account  for  the  fact  that  light  is 
propagated  in  a  straight  line.  Sound, 
water,  and  all  other  forms  of  waves  with 
which  we  are  acquainted  bend  around  cor- 


T 


A    Simple    Apparatus    for    Measuring  the 
Candlepower   of   an    Incandescent    Lamp  Is 
Readily  Constructed  as  Shown. 


ners,  whereas  light  does  not.  The  German 
Band's  melodious  (?)  strains  (on  the  ear) 
are  readily  heard  from  around  the  corner, 
but  the  players  cannot  be  seen,  because  of 
this  fact.  During  the  last  century,  how- 
ever, this  difficulty  has  been  removed  com- 
pletely, and  it  has  been  found  that  light  has 
other  properties  which  can  be  satisfactorily 
explained  by  the  wave  theory  and  not  by 
any  past  theory. 

In  the  preceding  lesson  it  was  indicated 
that  if  the  Wave  Theory  is  to  be  accepted, 
we  must  hold  the  same  view  as  Huygens, 
namely  that  all  space  is  filled  with  a  medium 
called  the  ETHER,  in  which  these  light 
waves  travel.  This  medium  is  altogether 
different  from  the  ordinary  forms  of  mat- 
ter, for  if  any  of  the  ordinary  forms  of 
matter  permeated  interplanetary  space,  the 
motion  of  the  planets  and  other  heavenly 
bodies  would  be  retarded,  while  as  a  matter 
of  fact  no  such  retardation  has  been  ob- 
served by  the  astronomers  during  these 
many  centuries,_  despite  the  extremely  ac- 
curate observations  that  have  been  made. 
Hence  our  ETHER  has  a  density  infinitely 
small  even  in  comparison  with  such  light 
gases  as  Hydrogen.  The  existence  of  ether 
is  now  practically  universally  assumed  by 
scientists  thruout  the  entire  world. 

It  should  be  noted  at  this  point  that 
wireless  waves  are  also  waves  of  the  ether 
and  resemble  light  waves  in  many  respects. 
(This  will  be  taken  up  in  detail  in  a  later 
lesson.) 


EXPERIMENT  51— 

INTENSITY  (Brightness)  OF  LIGHT 
— Place  four  candles  in  a  straight  line  be- 
hind an  upright  pencil,  and  catch  the  shad- 
ow of  the  pencil  on  a  white  piece  of  card- 
board or  other  screen.  The  room  should  be 
well  darkened.  Place  one  candle  up  closer 
to  the  pencil  and  not  in  the  line  of  the  four, 
thus  catching  another  shadow  on  the  screen. 
If  now  the  one  candle  is  moved,  a  position 
will  be  found  when  the  two  shadows  are 
equally  dark.  Hence  the  illumination  pro- 
duced at  the  screen  by  the  one  candle  and 
by  the  four  candles  is  the  same.  If  now  the 
distances  are  measured  from  the  screen  to 
the  candles  it  will  be  found  that  the  four 
candles  are  twice  as  far  from  the  screen  as 
the  one  candle. 

This  is  experimental  proof  that  the  in- 
tensity of  light  varies  inversely  as  the 
square  of  the  distance,  i.  e.,  the  nearer  the 
source  of  light  the  greater  the  intensity  or 
brightness  of  the  light,  and  greater  as  the 
square  of  the  distance,  so  considerable 
brightness  is  gained  by  even  a  small  dis- 
tance approach  to  the  source.  Intensities 
of  light  are  usually  given  in  terms  of  can- 
dle-power, one  candle-power  being  defined 
as  the  amount  of  light  emitted  by  a  sperm 
candle  %  inch  in  diameter  and  burning  120 
grains  per  hour. 


How  the  Sharpshooter   Hits  the  Bull's-Eye 
Every  Time,  Even  Tho  He  Places  a  Piece 
of  Cardboard  Over  the  Front  Gun  Sight. 


An  apparatus  for  measuring  the  candle- 
power  of  an  incandescent  lamp  or  other 
light  can  be  easily  constructed  and  used. 
M  (Fig.  42)  is  a  meter  stick  or  yard  stick. 


How  Light  Passes  Thru  a  Convex  Lens  (A) 
and  a  Concave   Lens  (B).     The  Point  "F" 
Is  Called  the  Focal  Point. 


The  Various  Kinds  of  Lenses  in  General  Use. 


A  is  the  light  of  which  the  candle-power 
is  to  be  found.  C  is  a  standard  %  inch 
sperm  candle,  while  B  is  a  small  frame 
having  a  piece  of  white  paper  in  it,  the 
center  of  the  paper  being  spotted  with  oil 
or  grease.  A,  fi,  and  C  are  mounted  on 
small  blocks  having  grooves  just  large 
enough  so  that  they  will  fit  the  meter  stick 
and  slide  along  it  "freely.  Place  C  near  B, 
light  the  candle  but  not  A.  If  now  we 
look  at  screen  B  from  the  side  of  C  the 
oil  spot  appears  dark,  while  if  we  look  at 
B  from  the  side  A  the  spot  appears  lighter 
than  the  surrounding  paper.  WHEN  THE 
PAPER  IS  LOOKED  AT  FROM  THE 
SIDE  OF  GREATER  ILLUMINATION 
THE  OILED  SPOT  APPEARS  DARK, 
but  when  looked  at  from  the  side  of  lesser 
illumination  it  appears  light.    Obviously  if 


both  sides  are  equally  bright,  the  spot  ap- 
pears equally  bright  with  the  rest  of  the 
paper.  Hence  if  A  and  C  are  both  lighted 
and  moved  back  and  forth  until  the  spot 
cannot  be  distinguished  from  the  rest  of 
the  paper  we  know  that  the  illumination 
reaching  the  frame  from  both  A  and  C  is 
the  same.  Measuring  the  distances  from  B 
of  A  and  C  and  remembering  to  use  the 


Diagram  Illustrating  How  a  Beam  of  Light 
Is  Bent  or  Refracted,  as  A,  B,  C,  D,  in  Pass- 
ing Thru  a  Piece  of  Glass  M,  N,  O,  P. 


square  of  the  distances  we  compute  the 
candle-power  of  A.  This  apparatus  is 
known  as  the  Bunsen  (after  the  inventor) 
or  grease-spot  photometer,  and  is  still  used 
commercially. 

EXPERIMENT  52— 

Several  years  ago  I  saw  a  sharpshooter 
give  an  exhibition  of  excellent  shooting. 
At  the  close  of  the  exhibition  he  performed 
a  seemingly  marvelous  feat.  He  shot  at 
his  target  and  hit  the  bull's-eye  while  he 
had  a  piece  of  paper  stuck  over  the  front 
sight,  which  apparently  was,  as  he  said,  the 
equivalent  of  shooting  with  his  eyes  shut, 
(since  he  could  not  see  thru  the  cardboard). 
A  careful  study  of  Figure  43  will  expose 
his  trick.  A  is  the  target,  BC  the  cardboard 
stuck  over  the  barrel  in  front  of  the  front 
sight  "s,"  S  is  the  rear  sight,  E  and  "e"  are 
the  performer's  eyes.  With  the  eye  E,  the 
performer  sights  along  S  and  "s,"  and  sight 
"s"  appears  on  a  certain  definite  spot  in 
cardboard  BC.  With  eye  "e"  shut,  no  mat- 
ter in  what  position  the  gun  is  held,  "s" 
always  appears  on  the  same  spot  and  hence 
nothing  could  be  hit  by  the  performer  ex- 
cept by  chance.  However,  the  performer 
contrary  to  usual  custom  in  shooting  also 
holds  the  other  eye  open.  Hence  thru  eye 
"e"  he  sees  the  target,  provided  BC  is  just 
small  enough  so  that  the  straight  line  "e"-X 
(Continued  on  page  490) 


Diagram   Illustrating  the  Factors  Entering 
Into  the  Determination  of  the  "Focal  Length" 
of  Convex  and  Concave  Lenses. 


November,  1917 


THE   ELECTRICAL  EXPERIMENTER 


461 


™?  RADIO  LEAGUE 


^AMERICA 


H.  Gernsback,  Manager 


HONORARY  MEMBERS 

CAPT.  WH.G.  BULLARD.  U  S.N.  NIKOLA  TESL A 
PROF.  REGINALD  FESSENDEN     DR. LEE  DE  FOREST. 

W.  H.  Kirwan,  Master  of  Radio  Relays 


How  Radio  Amateurs  Can  Do  Their  Bit 

By  COMMANDER  D.  W.  TODD,  U.  S.  N. 
Director  Naval  Communications  and  Chief  Cable  Censor 


r\ECENTLY    the    Editor    of  The 

JL^  Electrical  Experimenter  asked 
t\  me  for  a  statement  as  to  how  the 
*-  Amateur  Radio  Operators  of  the 
country  can  be  of  most  service  dur- 
ing the  present  war.  I  am  very  glad  to 
answer  this  question,  and  I  hope  that  this 
matter  will  reach  the  attention  of  a  very 
large  number  of  Amateurs. 

The  Navy  is  greatly  in  need  of  radio 
operators  for  sea  duty,  and  every  oppor- 
tunity will  be  given  the  amateur  to  serve 
his  country.  There  was  probably  never  a 
time  in  the  history  of  amateur  wireless 
when  it  was  so  easy  for  a  boy  to  obtain  an 
unlimited  amount  of  training  and  of  prac- 
tical experience  without  spending  a  cent  for 
it.  In  fact,  it  is  not  necessary  for  a  boy 
to  have  the  slightest  knowledge  of  wireless 
telegraphy ;  all  that  is  needed  is  a  desire 
to  learn  and  a  willingness  to  serve  his 
country  in  time  of  need. 

The  Navy,  which  for  a  number  of  years 
has  been  known  as  a  vast  school  in  itself, 
has  taken  special  pains  to  provide  adequate 
facilities  for  training  radio  men.  Thru  the 
kindness  and  patriotism  of  the  authorities 
at  Harvard  University,  the  Navy  has  estab- 
lisht  a  Naval  Radio  School  at  Harvard, 
which  is  now  able  to  take  care  of  1,500 
pupils.  The  course  is  of  four  months'  dura- 
tion and  embraces  military  drill  as  well 
as  radiotelegraphy  and  allied  subjects. 

However,  men  are  not  sent  to  Harvard 
until  they  have  reached  an  operating  speed 
of  ten  words  per  minute  in  the  Continental 
code.  This  need  not  discourage  those  who 
are  interested,  for  preliminary  training  is 


given  at  no  less  than  nine  schools,  located 
at  the  various  Navy  Yards.  At  these 
schools  men  are  started  in  from  the  very 
beginning  and  prepared  for  the  course  at 
Harvard. 

It  is  a  very  simple  matter  to  obtain  this 
free  education.  There  are  two  ways  in 
which  it  can  be  done;  men  can  enlist  in  the 
regular  Navy  or  enroll  in  the  Naval  Re- 
serve Force.  The  difference  is  that  enlist- 
ments in  the  regular  Navy  are  for  a  period 
of  four  years  of  active  service ;  in  the  Na- 
val Reserve  Force,  enrollments  are  also  for 
four  years,  but  the  active  service  is  only 
for  the  period  of  the  war  or  such  longer 
time  as  the  President  may  see  necessary; 
in  time  of  peace,  men  can  resign  whenever 
they  desire.  In  time  of  peace  in  the  regu- 
lar Navy,  it  is  possible  to  secure  a  furlough 
without  pay  for  the  rest  of  an  enlistment 
when  a  man  does  not  desire  to  serve  the 
whole  enlistment.  Applicants  must  be  18 
years  old,  or  if  only  17,  must  have  the 
written  consent  of  parents.  They  must  also 
be  able  to  pass  the  required  physical  exam- 
ination; however,  minor  physical  defects  are 
often  waived. 

As  indicated  above,  there  is  every  oppor- 
tunity for  the  older  amateurs  to  get  a  val- 
uable education  free,  but  we  must  consider 
those  who  are  not  of  the  proper  age  or  for 
other  reasons  find  it  absolutely  impossible 
to  enter  the  Naval  Service.  The  question 
is  often  asked  as  to  how  they  can  be  of 
service,  too.  There  is  no  doubt  in  the 
world  that  they  can  be  most  useful  by  taking 

Up  LAND-LINE  TELEGRAPHY. 

It  is  a  surprising  fact  that  very  few  ama- 


teur radio  operators  are  familiar  with  the 
American  Morse  code,  yet  this  knowledge  is 
quite  essential  in  many  ways.  It  is  one  of 
the  requisites  for  a  Commercial  Extra  First 
Grade  license,  for  instance.  All  Navy  op- 
erators assigned  to  shore  duty  must  know 
both   codes,  for   all  shore  stations  have 

LAND-LINE   CONNECTIONS.      It    is    not    to  be 

denied  that  it  means  hard  work  to  learn 
the  other  code,  even  after  being  familiar 
with  the  Continental,  but  anything  that  is 
really  worth  while  requires  hard  work,  and 
since  it  is  quite  out  of  the  question  to 
authorize  amateur  radio  stations,  spare 
time  during  the  war  may  very  profitably  be 
utilized  thus. 

Any  increase  in  the  supply  of  Morse  op- 
erators will  be  of  great  importance  to  the 
country  from  a  military  point  of  view. 
Every  operator  not  eligible  for  military  duty 
who  secures  a  position  with  a  commercial 
company  may  be  the  means  of  releasing  a 
man  for  duty  with  our  Navy  or  Army. 
Both  the  Western  Union  and  Postal  Com- 
pany are  glad  to  get  operators,  at  salaries 
ranging  from  $60  to  $100  per  month. 
Women  are  gladly  taken  by  these  commer- 
cial companies,  if  they  are  competent  op- 
erators, while  they  are  not  eligible  for  sea 
duty  in  the  Navy. 

Any  amateur  who  desires  further  infor- 
mation should  present  himself  at  the  nearest 
Navy  Re crtiiting  Office,  where  all  features 
of  the  service  will  be  carefully  explained ; 
any  doubtful  points  should  be  referred  to 
Commander  D.  W.  Todd,  U.S.N. ,  Director 
Naval  Communications,  Southern  Building, 
Washington,  D.  C. 


An  Interesting,  Patriotic  Appeal  from  Stuart  W.  Pierson,  U.  S.  N., 

An  Old  Radio  Amateur 


U.  S.  Naval  Radio  School,  Harvard  Uni- 
versity, Cambridge,  Mass. 

September  16,  1917. 

The  Radio  League  of  America, 

233  Fulton  St.,  New  York  City. 

Dear  Sirs — Noting  in  the  October  issue 
of  the  Electrical  Experimenter  the  call 
for  radio  amateurs  to  offer  their  services 
to  the  government,  I  thought  it  might  be 
of  interest  to  know  what  I,  as  a  member  of 
the  R.  L.  O.  A.,  think  of  the  Navy  after 
two  months  of  service  in  same. 

I  joined  the  League  shortly  after  its  or- 
ganization {in  1914)  and  offered  my  serv- 
ices on  the  application  blank.  In  March 
of  this  year  I  was  notified  by  the  Com- 
munication Superintendent  of  the  Great 
Lakes  district  that  I  was  wanted  for  the 
Naval  Reserve.    Later  I  enrolled  in  the 


same,  but  was  not  called  at  once,  so  joined 
the  regular  Navy  and  immediately  went 
on  active  duty.  Spent  about  three  weeks 
at  Brooklyn  navy  yard  and  was  then  trans- 
ferred here  to  the  new  Naval  Radio  School 
at  Harvard  University.  "  Outside  of  the 
good  pay  I  am  receiving  and  the  satisfac- 
tion of  knowing  I  am  doing  my  duty,  I 
am  acquiring  valuable  assets  that  come  thru 
Naval  discipline.  Of  course  it  is  a  little 
hard  at  first,  but  as  Mr.  Herr  of  the  West- 
inghouse  Co.,  says  in  the  October  Elec- 
tricalv  Experimenter,  education  alone  will 
not  insure  success.  One  must  have  the 
necessary  qualities  of  courage,  tenacity, 
grit,  and  the  ability  to  take  reverses  and 
hardships  cheerfully.  These  qualities  are 
developed  to  great  extent  in  the  Navy  and 
at  the  conclusion  of  the  war  the  Navy 
man  will  be  prepared  to  take  up  his  edu- 


cation where  he  left  off  with  new  vigor 
and  he  will  have  the  stuff  to  make  good. 
Of  course  those  who  zvish  to  remain  in 
service  will  also  have  ample  opportunities 
to  get  a  permanent,  good  paying  position. 
From  almost  any  angle  one  cannot  fail  to 
see  the  benefits  to  be  received  by  joining 
the  Navy.  The  Navy  will  be  the  biggest 
factor  tozvard  bringing  the  conflict  to  an 
end  thru  the  reduction  of  the  efficiency  of 
submarine  warfare.  As  the  wireless  op- 
erator is  indispensable  to  the  Navy  it  is 
up  to  the  amateur  to  fill  the  need.  Wish- 
ing the  League  the  best  of  success  in  its 
campaign  for  radio  men  for  the  govern- 
ment, I  remain, 

Very  respectfully, 

Stuart  W.  Pierson,  U.S.N. 
Formerly  opr.  of  gPY. 


{Continued  on  next  page) 


462 


THE  ELECTRICAL  EXPERIMENTER 

Radio  Roll  of  Honor 


November,  1917 


AS  promised  in  our  October  issue,  we  are  publishing  in  this 
f\    issue  the  names  of  American  Radio  Amateurs  who  have 
/  %  voluntarily  come  forward  in  offering  their  services  as  radio 
-^-operators  to  our  Government. 

Up  to  the  time  of  going  to  press  (Sept.  25),  425  applica- 
tions were  received,  all  of  which  are  publisht  in  this  issue.  A 
fair  showing  for  the  first  month,  but  very  unsatisfactory  as  a 
whole.  We  want  thousands  more,  and  the  Government  needs 
these  names  at  once.  Amateurs  of  America!  Again  we  say,  come 
forward.  Show  your  good  will  and  your  patriotism.  After  the 
war  is  over,  YOU  will  be  humiliated  when  your  friends  ask  you: 
"Why  was  your  name  not  printed  in  the  Radio  Roll  of  Honor?" 
Yes,  we  ask  you,  WHY  NOT? 

Remember  signing  the  blank  appended  at  the  end  of  this  article 
does  not  send  you  into  the  trenches.  Indeed,  you  may  never  be 
called  at  all  for  service,  but  the  Government  ought  by  all  means  to 


have  your  name  on  file  in  case  your  services  should  be  urgently 
required.  Read  the  letter  by  Commander  Todd,  U.  S.  N.,  publisht 
above,  then  read  the  letter  of  Stuart  W.  Pierson,  U.  S.  N. — an 
old  amateur ; — this  young  man  is  in  actual  service  now  and  as 
you  may  judge  for  yourself,  he  likes  the  work  immensely. 

Now  amateurs,  let's  get  busy,  let's  show  the  world,  that  Amer- 
ican Amateur  Wireless  is  a.  great  institution,  unparalleled  and  un- 
matched in  any  country.    What  do  you  say,  fellows? 


&abto  &oll  of  Honor 


Editor's  Note.  For  obvious 
reasons,  the  city  addresses 
of  the  applicants  listed  be- 
low have  been  left  out.  Only 
the  name  of  the  Radio 
Amateur  as  well  as  the 
State  in  which  he  resides 
have  been  publisht.  Every 
applicant  listed  in  these  col- 
umns has  pledged  his  ser- 
vices to  his  country  as  a 
radio  operator. 

All  honor,  and  our  sin- 
cere congratulations  to 
every  young  man  whose 
name  appears  here. 


Alabama 

Jas.  M.  Crump 

Alaska 

Verne  Elliott 

Arizona 

Irwin  Harrison 
Fred  Roebuck 

Arkansas 

R.  N.  Turner 

California 

Paul  Nesbit 

B.  Ludlow 
Harold  Jaynes 
W.   E.  Maguire 
Robt.  Johnston,  Jr. 
Albert  Kober 
Ralph  Parker 

F.  Spiekerman 
R.  Stamback 

C.  Leslie  Stebbins 
Jack  Hyams 

S.  Kerckhoff 
Robert  Kroman 
Eldredge  D.  Barrett 
Albert  Lauretsen 
Jos.  Meyer 

Colorado 

Alison  Kurth 
Andrew  Berglin 
H.  G.  Eyth 

Connecticut 

Henn  Kulikowsk 
John  T.  Biot 
C.  D.  Ryder 
Geo.  E.  Hoke 
N.  V.  Bradshaw 
Thos.  W.  Cumming 
Dan  Latham 
C.  G.  Hallstrom 
Arthur  A.  Johnson 
T.  E.  Tohnson 
F.  W.  Abbott 

Delaware 

Raymond  Phillips 

District  of  Columbia 

A.  L.  Blakeslee,  Jr. 
J.  C.  Conner 

Florida 

E.  J.  Mazurewicz 
T.  H.  Moore,  Jr. 

Georgia 

A.  W.  Church 
George  Wilby 
Hugh  Schliestett 

Idaho 

Charles  Cherington 


Joe  Aiken 


Illinois 


James  T.  Murray 
John  Ralph  Watkins 
D.    E.  Peebles 
Owen  Jarboe 
J.  D.  Kingsley 
H.  R  Ferguson 
Eugene  E.  Amory 
W.   G.  Asmus 

G.  Waldo  Ball 
R.  J.  Beuerman 
R.   W.  Bowen 
Morrill  C.  Des  Isles 
Eugene  Ericson 
Louis  Flader,  Jr. 
Arthur  U.  Gardner 
Wesley  Harmeyer 
D.  V.  Johnson 
Chas.  J.  Keenan 
Arthur  Larson 
Fred  C.  Leemann 
Michael  M.  Ostropol 
William  E.  Preece 
Alex.  Sieber 

H.  E.  Smith 

J.    P.  Smarski 
Henry  Williams 
Harold  Newman 
Chas.   F.  Enz 
Geo.  E.  Burritt 
Frank  L.  Brittin 

Indiana 

Roland  J.  Brown 
M.  B.  Lowe 
Wilbur  Conrad 
M.  T.  McKee 
H.  S.  Ogden 
Howard  Moore 
Robert  Throckmorton 
Fred  L.  Wehr 

Iowa 

A.  V.  Molyneux,  Jr. 
A.   S.  Osgood 
Guy   L.  Beech 
Oscar  J.  Kost 
Virgil  Elliott 
Joe  Aiken 
A.  S.  Bolen 
H.  W.  Evens 
H.  L.  Phillips 
Donald  A.  Laird 
Tyle  W.  Barthel 
Huffman  Healy 

A.  B.  Church 

Kansas 

Ernest  C.  Brown 
Russell  Mannel 
Wm.  H.  Ritter 

Kentucky 

John  Allen  Evans 
Elby  Becker 

B.  Wagner 

Louisiana. 

Walter  C.  Leahy 

Maine 

C.  M.  Sinnett,  Jr. 
W.  Q.  Rittall 
Harold   La  Bree 
Harold  F.  Cates 
Francis  H.  Sleeper 
J.  M.  Stanley,  Jr. 
Richard  Saunders 

Maryland 

M.  Biser 

J.  A.  Trabrandt 

Fred  L.  Wehr 

Massachusetts 

B.  M.  Spencer 
Randolph  G.  Webber 
T.    W.  Buswell 
Wm.  E.  Blake 


Frank  Canney 
Gordon  G.  Goodwin 
O.  G.  Lohnes 
Chas.  McAuley 
S.  U.  Marie 
J.  H.  Nixon 
F.  J.  Rumford 
Rolland  Adair  Gould 
Chester  L.  Keene 
Ernest  R.  Hood 
Geo.  A.  Sweet,  Jr. 
Geo.  E.  Varnum 
James  Cashman 
Wallace  Hune 
Richard  A.  Stearns 
Crocker  Mann 
David  Merriam 
John  T.  Corcoran 
Manuel  L.  Goularte 
Leo  E.  Wuta 
Frank  Danforth 
O.  M.  Black 
F.  E.  Bern 
Francis  Durant 
Donald  Scott 
Wm.  L.  Delaney 
M.  Mac  Leod 
H.   L.  Sawyer 

Michigan 

Leon  Hansen 
C.  D.  Rickel 


Chas  J.  Monroe 
L.  N.  Houbroyd 
D.  B.  Templeton 
Russell  W.  Finger 
Theo.  Chamberlain 
Stephen  j  ussel 
S.  F.  Warner 
H.  P.  Lang 
Edwin  Lentz 
Fred  F.  Dennis 
George  F.  Harrington 
Joseph  O.   L.  Higmegee 
Daniel  J.  Corin 
Wm.  A.  Floyd,  Jr. 
W.  E.  Cranston,  Jr. 
Howard  Bering 
H.   A.  Enderwoods 
Elmer    C.  Diehl 
Milton  Heizmann 
W.  G.  Hunt 
Alfred  C.  Mills 
Alfred  C.  Oechler 
Clarence  Rossnagel 
Joseph  F.  Grece 
Clarence  A.  Taylor 
Geo.  Thomas 
Fred  Walch 
Edwin  Herrmann 
Maxted  Clinch 
Chas.  Hampton 
L.  &  L.  Turner,  Jr. 
F.  Franklin 


AMATEURS! 

YOUR 

NAME  HERE? 


N.  Schlaack 
Wm.  H.  Kibbe 
Wm.  Forbey 
David  M.  Goodman 
Roy  Flint 
Earle  Moyer 
Sam  Blumenthal 
Harold  L.  Fleming 
Ole  B.  Ritchey 
Harry  H.  Lee 
Fred  B.  Daniels 
W.  Knowles 

Minnesota 

Arthur  W.  Stevenson 
Robert  Ramage 

Missouri 

E.  D.  Muhleman 
Lester  L.  Sanks 
Carl  Menke 
T.  Y.  Parsons,  Jr. 
P.  Poison 
Fred  Schillig 
Harry  Longmire 
Cyrus  R.  Truitt 
A.  Eppenauer 

Montana 

Roland  Ward 

Nebraska 

Gordon  S.  McKenzie 
Toe  W.  Havlicek 
H.  Havlik 
Donald  Burdick 
Douglas  Binghardt 

New  Jersey 

Thomas  W.  Braidwood 


New  Mexico 

Jos.  S.  Rhodes,  Jr. 

New  York 

Warner   G.  Palmer 
Don  Baxter 

F.  Van  Duzer 
Earl  Paddock,  Jr. 
Carleton  Brewster,  Jr. 
Robert  Anders,  Jr. 

G.  M.  Babcock 
Geo.  D.  Burns 
T.  D.  Callan 
J.  Carlsen 
Ed.  B.  Dyer 
Chas  Falco 

Geo.  M.  Ferguson 

E.  G.  Gehret 
R.  C.  Gillies 

W.  E.  Haeussler,  Jt. 

H.  C.  Hoehle 

F.  C.  Krummel 
Albert  O.  Leitch 
Arthur  Lowe 
Harold  McLea 

P.  Neyland 
Tohn  E.  O'Brien 
H.  L.  Osterby 
Peter  Pappas 
Clifford  R.  Paul 
Jos.  Peterson 
J.  E.  Adams 
Chas.  Ramsgate 
James  T.  Ruddy 
Harold  Sorensen 
John  Timmons 
Prentice  Warren 
M.  F.  Bohneberg 
John  Quinn 
Orimel  W.  Saxton 


C.  Benjamin 
Paul  Widmer 
Conway  Sheevin 
Clarence  J.  Roberts 
James  Welch 

D.  B.  McKinney 
R.  H.  Collignon 
Ernest  Hemann 
Walter  S.  Strong 
Sam'l  Christie 
Leonard  J.  Edick 
R.  A.  Clapp 
Howard  A.  Crowe 
George    Grant  Felt 
W.  L.  Miller 
George  Miller 
Earl  H.  Ivanson 
Clifford  McDonald 
Lester  C.  Palmer 
Frank  Russell 
Fred.  A.  Shelley 
R.  Anderson 
J.  H.  Appel,  Jr. 
Theodore  J.  Berger 
David  Carruthers 
James  Caulfield 
Arnold  Conard 
M.  Conroy 
Monte  Cohen 
Clifford  Cox 
Arthur  Davidson 
A.  Saenz  de  Calahorra 
Harold  H.  De  Palma 
C.  F.  Doebler 
Alan  C.  Dunn 
Alex.  Elkin 
C.  B.  Embler 
Alfred  Farago 
Wm.  Glameyer,  Jr. 

A.  A.  Goldon 
Alfred  H.  Hausrath,  Jr. 
Chas.  Hettenbach,  Jr. 

F.  E.  Hubbard,  Jr. 
Donald  B.  Jackson 
Fred.  Katz 
H.  D.  Kauffmann 

North  Carolina 

H.  E.  Norwood 

G.  T.  Finger 
O.  C.  Pate 

B.  W.  Laws 

North  Dakota 

Harry  Holmberg 
A.  R.  McKenzie 

C.  Crawford 

Ohio 

Harold  H.  Foltz 
Ralph  Frase 
J.  W.  Mintz 
Tack  Gritton 
C.  B.  Wilke 
Walter  Kottmeier 
Jerry  John  Manning 
Louie  Mansfield 
L.  H.  Reiner 
Donice  Hinton 
Wm.  G.  Finch 
Carl  P.  Goetz,  Jr. 
J.  F.  Riehle 
Ed.  K.  Ackerman 
Russell  G.  Anderson 
Marvin  Bower 
Harry  Bubb 

E.  A.  Call 
Louis  Charnicky 
Fred.  D.  Frey 
Tohn  Garse 
Robt.  Gottschatt 
Richard  Koenig 
Jack  Patterson 
Ladiman  Stasting 
P.  C.  Helwig 
Wm.  F.  Justus 
J.  E.  Purcell 

(Continued 


F.  M.  Reeves 
Gilbert  Vogel 
Loren  Wilcox 
Elmer  Wright 
P.  S.  Gregory 
H.  W.  Jones 
W.  Bernard  Merrick 
Bert  Osborne 
Stephen  Spitler 
C.  J.  Linxweiler 
Lloyd  Rider 
Carl  Eberhart 
Paul  Loub 
Wendell  Ashcroft 
J.  L.  Leppert 
Ned  Eachus 
John  Frazier 
C.  M.  Osmbaugh 
Miles  Bruning 
George  S.  Yerigan 
Wm.  F.  Ball 
Chas.  Frank 
J.  B.  Stewart 

Oklahoma 

Donovan  Tool 
Varnahale  Jones 
Warren  C.  Clark 

Oregon 

Alfred  J.  French 
Morris  Knapp 
A.  D.  Rimyard 
Arthur  E.  Gibbs 

Pennsylvania 

J.  S.  Bernhard 
Blair  Cunningham 
Roger  B.  Hernandez 
Wm.  J.  Kreis 
J.  A.  Welle,  Jr. 
Jno.  P.  Cunningham 
Wm.  S.  Schmidt 
Robt.  McKee 
Paul  Elliott  Fischler 
Stanley  Phillips 
J.  L.  Kirk 
Marvin  Madden 
Otto   Von  Kories 
H.  J.  Cramer 
Chas.  J.  Mehing 
Sam'l  S.  Szeinbach 
Wm.  S.  Louchheim 
Ernest  Walker 
Daniel  Tones 
R.  W.  Hornung 

A.  L.  Rockefeller 
R.  Ellis  Tinkins 
H.  N.  F.  Craige 
Tohn  H.  Weikel 
Wilbur  J.  Murdock 

E.  L.  Petit 

F.  H.  Riordan 
Geo.  M.  Albright 
H.  G.  Brantigane 
Leroy  Mickay 

B.  J.  Bisciotti 

Rhode  Island 

Ed.  B.  Davis 
Earl  C.  King 
Lewis  J.  Boss 
Thomas  S.  Healy 
Kenneth  Hiorus 

South  Dakota 

Howard  van  Benthuysen 

Tennessee 

Conrad  E.  Roberts 
Geo.  O'Neil  Sutton 

Texas 

W.  H.  Tilley 
Edgar  Crampton 
L.  B.  Dobbs,  Jr. 
James  L.  Autry,  Jr. 
on  page  500) 


November,  1917 


THE  ELECTRICAL  EXPERIMENTER 


463 


New  Radio  Submarine  to  Foil  U-Boats 


THE  illustration  shows  a  new  sub- 
marine controlled  by  wireless  which 
may  rout  the  Teuton  U-boats.  It 
is  Robert  Morton's  model  of  a 
wonderful  radio  diver  invented  in 
his  Los  Angeles  laboratory. 

Recently  Mr.  Morton,  using  an  800 
pound  model  of  his  invention,  held  an 
audience  spellbound  while  he  demonstrated 
it  in  a  huge  tank.  The  model  swam  the 
length  of  the  tank  as  Mr.  Morton  touched 
the  key  of  the  wireless  transmitter.  An- 
other touch  reversed 
the  propellers  and  the 
model  returned  to  its 
base.  Then  an  ether 
wave  opened  the 
valves  of  the  little 
craft  and  it  sank  until 
only  its  antennae  were 
showing.  A  tiny  tor- 
pedo attached  to  the 
bow  was  then  releas- 
ed by  wireless  and 
sped  to  the  end  of  the 
tank. 

"I  can  make  a  fifty 
foot  submarine  on 
these  lines,"  the  in- 
ventor said,  "fill  it 
half  full  of  nitro- 
glycerin, guide  it  into 
the  Kiel  Canal  from 
an  aeroplane  and  des- 
troy every  ship  within 
a  mile,  or  it  can  be 
guided  into  the  mine 
fields  of  Helgoland, 
blow  it  up  and  sweep 
the  entrance  to  the 
German  base  clear  of 
mines.  It  simply  means  using  the  sub- 
marine as  a  huge  mine." 

[Those  interested  in  radio-controlled  ves- 
sels should  read  the  article  in  the  October 
issue,  page  390,  entitled — "A  Radio  Con- 
trolled Model  Boat,"  by  H.  C.  Van 
Benthuysen  and  Max  I.  Black. — Editor.} 


lations  to  go  to  the  rescue,  relayed  the 
call  and  in  about  20  minutes  picked  up  a 
radio  from  an  American  destroyer,  reading : 
"We  will  reach  vou  in  one  hour." 


PERSONNEL  OF  A  RADIO  SIGNAL 
COMPANY. 

A  radio  company  of  the  Signal  Reserve 
Corps  is  commanded  by  a  captain  and  is 
composed  of  the  following  personnel :  A 
captain  and  two  first  lieutenants,  mounted. 

The   enlisted  men   are  a  master  signal 


urges  that  more  women  be  enlisted  in  the 
service.  The  letter  reads  that  women 
telegraphers  are  in  demand  by  the  govern- 
ment for  both  the  army  and  navy.  They 
will  not  be  taken  abroad  however.  Their 
assignments  will  be  at  shore  stations. 


One  of  the  Latest 
Which  Its  Inventor 


WIRELESS  LOG  OF  A  SEA  CRIME. 

A  succession  of  wireless  calls  telling  the 
story  of  a  sea  tragedy,  in  which  an  un- 
known steamship  was  the  victim  of  a  Ger- 
man submarine,  are  recorded  in  the  log 
of  a  neutral  vessel  which  arrived  "in  an 
Atlantic  port"  recently  from  a  "Scandin- 
avian port." 

The  calls  were  recorded  while  the  neu- 
tral vessel  was  passing  close  to  the  Irish 
coast,  on  her  way  to  this  port,  and  begin 
with  the  international  "S  O  S,"  followed 
by  the  message  : 1 

"We  are  being  chased  by  a  submarine." 

Ten  minutes  later,  the  log  shows,  the 
following  was  heard  :  "Hurry  assistance  ; 
we  are  being  shelled." 

A  lapse  of  IS  minutes  followed,  then  the 
entry:  "Ship  is  on  fire  and  sinking;  cap- 
tain ordered  men  to  lifeboats." 

Five  minutes  later  comes  the  final  mes- 
sage thru  the  air :  "We  are  done  for," 
giving  also  the  position  of  the  ship. 

The  neutral  vessel,   forbidden  by  regu- 


and  Most  Promising  Models  of  a  Radio-Controll 
Hopes  to  Blast  His  Way  Thru  German  Mine  F 
Base  Itself. 

electrician,  technical  expert  of  the  radio 
company,  in  charge  of  making  repairs  and 
adjustments  to  wireless  telegraph  ap- 
paratus. 

Six  sergeants,  first  class ;  one  assists  the 
captain,  handling  questions  of  supplies, 
finances,  etc.,  and  five  radio  operators  act- 
ing as  leaders  of  the  five  sections  of  the 
company. 

Nine  sergeants — a  supply  sergeant,  a 
stable  sergeant,  a  mess  sergeant,  one  en- 
gineer for  the  gas  engines  and  five  acting 
as  first  assistants  to  section  leaders. 

Fifteen  corporals,  one  farrier,  one. 
saddler,  one  company  clerk  (office  work), 
two  mechanics  (miscellaneous  repair  work) 
and  ten  operators  assigned  to  sections. 

Thirty-five  privates,  first  class ;  two 
trumpeters,  two  drivers  and  thirty-one  pri- 
vates assigned  to  sections.  Six  privates, 
one  horseshoer  and  two  cooks. 

All  are  mounted  except  one  mess  ser- 
geant, two  mechanics  and  two  drivers.  The 
arms  carried  are  automatic  pistols. 


MANY  STUDENTS  TAKE  U.  S. 
WIRELESS  COURSE. 

Many  students  are  taking  the  course  of 
radio  telegraphy  in  the  U.  S.  Radio  School, 
Parkway  Building,  Philadelphia,  Pa. 

More  than  300  stu- 
dents are  taking  the 
course.  The  school  is 
under  the  direction 
of  Lieutenant  G.  Y. 
Cadmus,  U.  S.  R.  C., 
and  was  established 
when  the  government 
decided  to  educate  a 
corps  of  several  thou- 
sand radio  operators 
for  marine  service. 

According  to  re- 
ports issued  by  the 
staff  of  instructors 
the  end  of  the  first 
six  months'  course 
will  see  more  than 
400  operators  grad- 
uated from  the 
school,  who  will  be 
licensed  as  second- 
class  operators.  It  is 
also  said  that  a  num- 
ber of  the  men  will 
be  recommended  for 
the  special  course  in 
radio  telegraphy  given 
at  Princeton  Uni- 
versity. 

Previous  to  the  graduating  of  the  pres- 
ent class  of  students  at  the  radio  school  in 
the  Parkway  Building,  enrollment  for  the 
second  class  will  start.  According  to  plans 
announced  by  those  in  charge  of  the  school, 
preparations  will  be  made  to  accommodate 
more  than  500  pupils.  The  government  will 
need  more  than  5,000  wireless  operators 
for  marine  service  within  two  years. 


ed  Submarine,  With 
ields  to  Their  Naval 


WOMEN  MAY  ENTER  THE  WIRE- 
LESS SERVICE. 

Women  are  entitled  to  the  study  of  wire- 
less telegraphy,  the  same  as  men,  in  the 
class  organized  by  Prof.  Harvey  Anthony 
of  the  Muncie.  Ind..  high  school,  and  it  is 
hoped  that  many  will  file  their  applications. 

A  communication  received  recently  by 
Prof.  Anthony  from  the  war  department 


A  WORLD'S  RECORD:  RADIO 
HEARD  13,000  MILES. 

A  radio  message  has  been  intercepted 
half  way  around  the  world  at  last.  Using 
an  Audion,  radio  operator  J.  L.  Davies  at 
Radio  Awarna,  Invercargill,  New  Zealand, 
has  accomplisht  this  feat.  In  a  recent  let- 
ter to  Dr.  Lee  de  Forest,  the  well-known 
radio  authority,  Mr.  Davies  says  in  part : 
"In  my  experimental  work  at  present  it 
may  interest  you  to  learn  that  using  Audion 
bulbs  of  the  double  grid,  double  plate  type, 
I  am  daily  receiving  stations  antipodally 
situated  in  respect  to  this  station.  Dis- 
tances of  13,000  miles  are  covered  and 
some  of  the  many  stations  at  about  that 
distance  that  I  pick  up  are  "Eilvese,  Ger- 
many; Eiffel  Tower,  Coltana,  Las  Palmas, 
etc.,  Eiffel  Tower  is  easily  copied  on  the 
typewriter,  owing  to  the  geographical  po- 
sition of  my  station."  The  distances  men- 
tioned are  indisputably  world  records. 


464 


THE  ELECTRICAL  EXPERIMENTER 


November,  1917 


BEING  A  NAVAL  WIRELESS  MAN. 
By  Howard  S.  Pyle. 
Electrician  Radio,  U.  S.  Navy. 

AS  I  6it  here  on  watch  in  the  early 
morning  hours,  1  think  of  many 
"  things  and  my  thoughts  naturally  turn 
to  the  good  old  amateur  days  "back  home" 
where  we  used  to  "cuss  the  other  fellows" 
for  QRM  more  than  we  would  OK  for  bix 
from  the  whole  "Ham  tribe."  Those  were 
indeed  the  "Happy  days"  but  are  now 
temporarily  a  thing  of  the  past.  But  why 
should  we  lose  the  fascinating  recreation 
of  listening  to  the  song  of  the  spark? 
Why?  I  asked  myself  that  question  when 
we  were  closed  down  and  decided  not  to. 
I  hiked  myself  to  the  nearest  Marconi 
office  and  got  an  assignment — back  on  the 
dear  old  air  again  and — contented.  But 
commercial  service  today  is  not  what  it 
was  before  the  war.  Very  little  bix  I 
found,  handling  only  four  or  five  messages 
an  entire  trip  of  eleven  days  and  on  a 
passenger  boat  with  a  full  passenger  list 
too.  To  the  real  dyed-in-the-wool  "Ham," 
this  business  of  three  or  four  "msgs"  a 
week  is  not  particularly  attractive  for  the 
more  bix  the  better,  as  we  get  a  chance  to 
operate  then.  I  felt  that  way  about  the 
commercial  game  so,  knowing  many  of  the 
fellows  who  had  entered  the  Navy  service, 

SUCCESSFUL  LOOSE  COUPLER 
BUILT  FROM  "E.  E."  SUPPLEMENT 

Herewith  is  a  photo  of  the  Receiving 
Transformer  I  built  from  the  Blue-print 
Supplement  of  the  Experimenter,  but  the 
photo  does  not  give  the  instrument  justice 
because  it  does  not  show  the  color  and 
workmanship,  but  it  is  a  "beauty"  and  it  is 
a  5,000  meter  instrument. 

I  am  building  an  Oudin  high  frequency 
coil  as  described  in  the  May  Experimenter 
and  expect  to  have  it  completed  soon. 

I  sure  do  like  the  "E.E.",  I  would  not 
take  a  hundred  dollars  for  the  copies  I 
have  on  hand  if  I  could  not  get  any  more 
like  them;  they  have  helped  me  up  to 
where  I  am  now,  1  am  an  Electrician  by 
trade  and  an  Experimenter  after  work 
hours.  I  am  building  nearly  all  of  my  ap- 
paratus. 

I  have  been  reading  the  "E.E."  for  about 
two  and  one-half  years  and  when  I  want 
to  learn  something  that  I  don't  know  I  con- 
sult the  Experimenter  and  I  nearly  always 
find  it. 

The  Experimenter  is  the  experimenter's 
"STAND-BY." 


Now  and  Then  We  Do  Hear  from  Our  Readers.    Here's  the  Fine 
Loose  Coupler  One  of  Them  Built  from  a  Description  Given  Some 
Time  ago  in  "The  Electrical  Experimenter." 


"Upholding  the  Stars  and  Stripes  and  the 
Experimenter." 

I  remain  (what  we  would  call  a  100% 
American)        ARTHUR  J.  BARRON. 


I  decided  to  look  into  the  thing.  None  of 
them  appeared  to  be  over-enthusiastic  about 
Navy  wireless. 

I  almost  felt  sorry  for  them  for  I  never 
have  considered  pounding  a  key  work,  so 
I  went  farther.  The  Navy  Yard  was  my 
next  port  of  call  and  there  I  had  a  talk  with 
the  DCS  (district  communica- 
tion sup't),  a  Naval  Lieuten- 
ant. He  offered  me  an  assign- 
ment to  NPD  and  painted  a 
word  picture  of  the  place 
which,  altho  not  making  it  ap- 
pear a  particularly  attractive 
berth,  yet  seemed  to  offer  great 
opportunities  in  the  wireless 
game  so  I  entered  the  service 
as  "Electrician  Radio"  and 
received  orders  to  report  to 
Tatoosh  Island,  NPD,  at  once 
for  active  service. 

After  a  succession  of  cir- 
cumstances I  found  myself  at 
the  Island — a  large  rock  of 
about  17  acres  extent.  A  gov- 
ernment weather  bureau,  light- 
house and  wireless  station  just 
about  occupied  all  the  available 
space  and  the  buildings  were 
of  the  usual  substantial,  neat 
construction  characteristic  of 
all  Government  institutions.  I 
reported  for  duty  and  was  as- 
signed sleeping  quarters  which 
I  was  surprised  to  find  equal 
to  a  first-class  hotel,  as  I  had 
imagined  it  to  be  rather  a 
primitive  life  on  the  Island. 
Quite  the  contrary,  iho,  as  we 
have  all  modern  cor  veniences 
such  as  hot  and  cold  running 
water,  electric  lights,  bath,  etc. 
I  also  found  the  enlisted  men 
fine  fellows  and  very  congenial ; 
feeling  at  home  with  them 
right  away.  At  "mess"  another 
surprise  greeted  me  in  the  ex- 
cellent quality  (and  quantity) 
of  the  food  served.  Altogether 
my  first  day  was  a  succession 
of  surprises.  I  found  the 
"Electrician  in  Charge"  a  man  of  the 
highest  type  and  he  gave  me  my  first  day 
to  get  acquainted. 

The  following  day  I  broke  in,  taking  a 
regular  watch,  which  is  varied  each  day  so 
that  no  operator  has  the  same  watch  in  suc- 
cession, permitting  a  full  night  "in  the  hay'' 
every  fifth  night.  I  was  given  the  Mid- 
watch  or  from  midnight  to  4  A.  M.  (we 
only  work  4  hours  a  day)  and  found  no  busi- 
ness that  'eve,  which  was  indeed  lucky  as  it 
gave  me  a  chance  to 
get  used  to  the  outfit 
and  forms  of  Gov- 
ernment transmis- 
sions. However,  since 
that  time  I  have  found 
each  watch  busy 
enough  to  satisfy  me 
without  rushing  a  fel- 
low. 

On  the  whole  I  am 
well  pleased  with 
Navy  wireless  and  am 
considering  staying 
with  it  at  the  close  of 
hostilities. 

I  also  know  that  I 
am  doing  my  bit  for 
"Uncle     Sam"  and 
want  to   urge  every 
amateur  and  operator 
to  enter  the  service  it 
at  all  possible,  as  The 
Navy  is  in  great  need 
of  wireless  men  and 
it  is  your  chance  to  serve  your  country. 
In  addition  to  this  you  receive  the  best 
training  in  the  art  that  is  possible,  for 
the  Government  does  things  right. 


FIRST  WOMAN  RADIO  OPERATOR 
GRADUATES  AT  HUNTER  COL- 
LEGE, N.  Y. 

The  women  of  America  are  rapidly  com- 
ing to  the  front  in  military  affairs,  as  wit- 
ness the  accompanying  illustration  of  Miss 


The  First  Woman  Radio  Operator  to  Graduate  at  Hunter 
College,  N.  Y.  Miss  Elizabeth  Rickard  Is  Her  Name  and 
Uncle  Sam  Has  Awarded  Her  a  "First  Grade  Commercial 
License"  as  Radio  Operator.    Let  Us  Have  More  of  'Em. 


Elizabeth  Rickard,  first  radio  graduate  of 
Hunter  College,  New  York  City.  This 
institution  has  a  very  enthusiastic  wireless 
class  who  are  blest  with  every  provision 
for  quickly  assimilating  the  intricacies  of 
radio  telegraphy.  The  Marconi  Wireless 
Telegraph  Company  of  America  presented 
the  college  with  a  standard  commercial 
radio  transmitting  and  receiving  apparatus. 
Special  instructors  have  been  provided  also, 
so  that  the  girls  who  graduate  here  are 
fully  equipt  to  take  up  commercial  or  naval 
duties.  The  U.  S.  Navy  Department  has 
intimated  that  women  radio  operators  may 
be  placed  in  charge  of  land  stations,  and 
in  this  way  relieve  badly  needed  men  oper- 
ators for  active  duty  on  board  ships  or 
abroad.  The  new  merchant  fleet  which  the 
Shipping  Board  is  now  building  will  also 
require  a  large  number  of  radio  operators. 
The  outlook  for  radio  operators  is  there- 
fore very  bright  and  after  the  war  there 
will  be  plenty  of  work  also  for  many  years 
to  come. 

Miss  Rickard  entered  the  Wireless  Class 
for  women  at  Hunter  College  in  April,  1917, 
and  was  detailed  to  the  Marconi  School  for 
intensive  training  in  May.  She  past  the  test 
given  at  the  Marconi  School  in  the  first 
week  of  July  and  received  complimentary 
mention  of  her  paper,  her  instructor 
saying  it  was  the  best  submitted  out  of 
a  class  of  20  men  and  3  women.  On  July 
12th  she  went  up  for  her  Navy  test  and  re- 
ceived the  highest  possible  rating  and  was 
granted  a  First  Grade  Commercial  License. 
Miss  Rickard  had  done  nothing  in  wireless 
before  the  first  of  January,  1917.  She 
showed  unusual  ability. 


November,  1917 


THE  ELECTRICAL  EXPERIMENTER 


465 


A  DUST-PROOF  COUPLER- 
SWITCH. 

Herewith  is  a  sketch  of  a  dust-prcof 
secondary  switch  for  loose  couplers  which 
has  proven  highly  satisfactory,  besides 
greatly  improving  the  appearance  of  any 


A  Good  Way  to  Build  Dust-Proof  Coupler 
Switches.      The    Square,    Revoluble  Shaft 
Turns  the  Sleeve  to  Which  the  Switch  Blade 
Is  Attached. 

coupler.  It  also  does  away  with  expen- 
sive switch  points  as  any  old  ones  will  do, 
as  they  are  not  seen.  The  blade  is  swung 
by  turning  the  square  brass  rod  A  by  means 
of  knob  B.  This  square  rod  goes  thru 
bushing  E  or  a  counter  bushing  inside_  of 
E,  which  has  a  square  opening.  The  switch 
blade  is  securely  fastened  to  it.  The  en- 
tire switch  and  secondary  move  along  the 


rod,  but  when  B  is  turned,  the  switch  ro- 
tates accordingly.  A  spring  (I)  may  be 
used  to  make  a  better  contact.  The  sec- 
ondary may  be  moved  more  easily  if  a 
knob  G  is  mounted  handy  as  shown. 
Contributed  by  NEVIN  BRENNER. 


PENDULUM    OPERATED  BUZZER 
TEST. 

It  may  be  attached  to  any  clock,  but  one 
tector  buzzer  test  by  other  means  than  a 
hand  or  foot-operated  key,  thus  leaving 
the  operator  entirely  free  to  manipulate  the 
instruments.  By  utilizing  the  pendulum 
movement  of  a  clock  a  very  reliable  auto- 
matic tester  can  be  had  and  the  operating 
expenses  are  nil. 

It  may  be  attached  to  any  clock  but  one 
having  a  pendulum  speed  of  about  fifty 
to  seventy  beats  per  minute  is  preferred. 
If  the  clock  is  in  the  operating  room  it 
will  operate  the  buzzer  direct,  otherwise 
a  relay  should  be  used. 

Secure  a  piece  of  silver  foil  around  the 
pendulum.  Obtain  a  very  thin  spring  sev- 
eral inches  long  (about  No.  32  B  &  S  gage) 
and  wrap  silver  foil  at  one  end.  The  other 
end  is  secured  to  the  woodwork  of  the 
clock  in  such  a  manner  that  the  pendulum 
just  barely  makes  a  contact  on  each  swing. 
This  can  be  ascertained  best  after  the  buz- 
zer has  been  connected.  Two  leads  are 
taken  from  the  buzzer  circuit,  one  is 
grounded  to  the  metal  frame  work  of  the 
clock,  the  other  is  connected  to  the  spring. 
Care  must  be  observed  that  the  spring  is 
not  too  short  or  it  will  interefere  with  the 
proper  working  of  the  clock. 

I  have  used  an  arrangement  as  described 
and  found  it  "always  on  the  job"  when 
switched  on.  It  also  can  be  connected  to 
your  own  radio  transmitter  to  give  imita- 


tions of  NAA,  etc.  Of  course  a  relay 
should  always  be  used  where  heavy  cur- 
rents are  to  be  handled. 

Contributed  by  CHARLES  M.  FITZ- 
GERALD. 


MAKING  AN  OMNIGRAPH  OPER- 
ATE STUDENT'S  HAND. 

Train  the  hand  as  well  as  the  ear  to 
learn  the  code  rapidly  and  proficiently. 
Receiving  the  dots  and  dashes  thru  the 
hand  opens  a  new  path.  Rig  up  a  tele- 
graph key  so  that  the  lever  may  be  worked 
up  and  down  by  a  solenoid  or  sucking  coil 
as  per  diagram.  The  solenoid  is  connected 
with  a  code  machine  such  as  the  Omni- 
graph  and  the  key  adjusted  to  work  like 
a  sounder ;  then  grasp  the  key  as  for  send- 
ing, but  let  the  key  operate  the  hand  in- 
stead of  the  hand  operating  the  key.  Com- 
bining this  operation  with  regular  sounder 
or  buzzer  practise  enables  one  to  become 
expert  on  the  double-quick.  Try  it, 
"hams." 

Contributed  by  FRANK  COPEMAN. 


EE 

j 

J              ^Solenoid  coil 

\    jjjjjjj                      BnpgB  Hey 

A  Clever  Scheme  for  Learning  the  Code 
Easily  and  Quickly.  A  Magnetic  Solenoid 
Connected  to  an  Omnigraph  and  Battery, 
Works  the  Key.  Thus  the  "Telegrapher's 
Touch"  Is  Acquired  Unconsciously. 


Development  of  Aircraft  Radio  in  the  Navy 

By  BENJAMIN  F.  MIESSNER 
Expert  Radio  Aide  U.  S.  N. 


That  the  Navy  realizes  the  necessity  of 
organized  scientific  research  of  its  special 
problems  and  the  development  of  special 
apparatus  to  meet  its  peculiar  require- 
ments, is  clearly  manifested  by  the  estab- 
lishment of  an  excellently  equipt  radio  lab- 
oratory at  the  Navy  Aeronautic  Station, 
Pensacola,  Fla. 

While  radio  signaling  over  the  earth's 
surface  is  largely  a  standardized  art  now, 
aircraft  radio,  altho  already  an  accom- 
plisht  feat,  has  thus  far  been  largely  a 
matter  of  cut-and-dry  guesswork  unguided 
by  accurate  scientific  data.  This  labora- 
tory, in  addition  to  its  work  of  testing  air- 
craft radio  apparatus  submitted  by  com- 
mercial manufacturers,  under  both  labora- 
tory and  service  conditions,  is  gathering 
valuable  scientific  data  pertaining  to  the 
peculiarities  involved  in  radio  signaling  be- 
tween isolated  points  above  the  earth's  sur- 
face, and  between  such  points  and  the 
earth's  surface,  as  distinguished  from  the 
usual  over-land  or  over-sea  signaling.  It 
is  also  developing  special  radio  and  other 
apparatus  for  naval  aircraft.  Being  in  ex- 
tremely close  touch  with  the  actual  air- 
craft conditions  and  requirements,  this 
laboratory  presents  unusual  opportunities 
for  thoro  study  and  development. 

The  naval  officers  having  jurisdiction  over 
this  work  are  Lieutenants  E.-  H.  Loftin, 
District  Communication  Superintendent, 
stationed  at  New  Orleans,  La.,  and  P.  N. 
L.  Bellinger,  Head  of  Experiment  and  Test 
Division  at  this  station. 

Altho  the  laboratory  has  been  in  exist- 
ence but  a  few  months  and  is  not  yet  fully 
equipt,  several  important  problems  have  al- 
ready   been    attacked    and  satisfactorily 


solved.    Among  these  may  be  mentioned : 

(1)  The  development  of  a  simple  inter- 
seat  telephone  for  pilot-student  or  pilot- 
observer  conversation  on  airplanes  under 
the  conditions  of  full  power  flight.  This 
work  was  undertaken  because  commercial 
apparatus  had  proven  entirely  unsatis- 
factory. Two  types  have  been  developed, 
the  first  of  which  requires  no  external 
battery  or  power  source,  and  which  in- 
corporates extreme  simplicity  and  rugged- 
ness  in  its  construction,  is  suitable  for  use 
under  the  moderate  noise  conditions  en- 
countered on  low  powered  airplanes ;  the 
second  of  these,  which  requires  an  outside 
battery,  may  be  used  under  the  most  severe 
noise  conditions  obtainable  on  present  air- 
planes without  exhaust  mufflers.  These 
telephones,  which  are  in  daily  use  for  in- 
struction purposes,  reduce  by  nearly  one- 
half  the  time  required  for  qualifying  stu- 
dent pilots,  by  permitting  constant  coach- 
ing from  the  instructor,  and  are  invaluable 
for  pilot-observer  communications  for  re- 
connaissance, spotting,  or  other  flying  in 
two-passenger  airplanes. 

(2)  An  exhaustive  study  has  been  made 
of  the  noise  conditions  affecting  radio  re- 
ception on  airplanes.  A  special  instrument, 
called  the  Noisemeter,  was  devised  with 
which  accurate  measurements  of  various 
airplane  noises  have  been  made.  Thou- 
sands of  measurements  have  been  made 
in  determining  the  noise-making  qualities 
of  various  aeronautic  motors,  the  efficien- 
cies of  muffling  devices,  the  intensity  of 
the  noises  at  varying  distances  and  at  vary- 
ing motor  speeds,  the  distribution  of  the 
noises  in  different  directions,  the  efficiencies 
of  radio  headgear  for  eliminating  airplane 


noises,  the  effects  of  airplane  noises  on  the 
ears,  the  noise-making  qualities  of  air  at 
varying  velocities,  etc. 

(3)  Exhaustive  measurements  and  tests 
are  being  made  on  every  conceivable  form 
of  airplane  antenna  to  determine  the  ad- 
vantages peculiar  to  each  type. 

(4)  The  most  recent  development  is  an 
entirely  new  type  of  radio  transmitter, 
which  constitutes  what  is  perhaps  the  great- 
est advance  thus  far  made  in  aircraft 
radio.  With  an  outfit  having  a  total  weight 
of  only  five  pounds,  designed  particularly 
for  spotting  work,  a  signaling  range  of 
from  ten  to  twenty  miles  is  easily  attained. 
The  space  considerations  are  negligible. 
With  another  larger  outfit,  weighing  only 
about  ten  pounds,  a  range  of  from  fifty 
to  seventy-five  miles  is  obtainable.  These 
weights  include  the  antenna  system  neces- 
sary for  radiating  the  radio  energy.  The 
full  significance  of  these  statements  is  not 
realized  unless  it  be  added  that  the  very 
best  commercial  apparatus  now  obtainable 
weighs  from  one  to  two  pounds  per  mile 
of  range,  and  occupies  a  space  of  from 
one  to  two  cubic  feet  per  twenty-five  miles 
of  range,  making  necessary  the  removal 
of  the  forward  controls. 

(5)  The  establishment  of  radio  instruc- 
tion classes  for  officers  undergoing  pilot 
training  has  not  been  neglected.  Group 
instruction  in  operating,  and  the  functions 
and  care  of  the  various  parts  of  radio  ap- 
paratus, is  given  on  such  days  as  are  un- 
suitable for  actual  flying. 

(6)  Other  devices  being  experimented 
with  are  aircraft  and  submarine  detection: 
apparatus  and  radio  direction-finders  for 
aircraft. 


466 


THE  ELECTRICAL  EXPERIMENTER 


November,  1917 


September  Meeting  of  Institute  Radio  Engineers 


AVERY     interesting    and  instructive 
paper  was  presented  by  Prof.  L.  A. 
Hazeltine,   September  5,   1917,  at  a 
meeting   of   the   Institute   of   Radio  En- 
gineers held  in  the  Engineering  Societies 
Building,  New  York  City. 

The  paper,  which  is  the  first  of  a  series  to 
be  presented  this  season  by  the  Institute, 
covers  the  subject  of  the  Audion  from  an 


In  This  Diagram  I  Represents  an  Oscillatory  Circuit 
Which  Is  Excited  by  a  Suitable  Means  and  Current 
Transferred  Inductively  to  Two  Split  Inductances, 
Which  by  Virtue  of  Their  Position  Produce  Re- 
generative or  Oscillatory  Action  in  the  System. 


entirely   different    side   than   ever  before 
read  before  the  Institute.     Prof.  Hazel- 
tine    showed    by    diagrams    and  stere- 
opticon  views   the   feasibility   of  measur- 
ing the  curve  of   the  transposed  energy 
from  the  grid  to  the  plate  and  the  for- 
mulas for  calculating  this  quantity.  By 
so  doing  he  illustrated  the  method  of 
determining  whether  an  Audion  would 
oscillate  or  not,  and  if  the  curve  was  too 
broad,  the  Audion  would  probably  not 
act  as  a  receptor,  but  could  be  used  as 
an  oscillator  or  amplifier. 

The  subject  certainly  aroused  quite  an 
interest  in  all  present,  and  Prof.  Hazel- 
tine  was  highly  commended  on  his  treat- 
ment of  a  heretofore  unthought  of  phase 
of  the  Audion.  The  lantern  views 
showed  past  and  present  Audion  hook- 
ups and  also  an  idea  of  those  to  be 
experimented  with  in  the  future.  Also 
a  discourse  as  to  the  merits  and  de- 
merits of  the  various  circuits. 

The  paper  was  discust  by  many  promi- 
nent men,  among  whom  was  Dr.  Lee 
de  Forest,  who  spoke  a  few  words  out- 
lining the  present  status  of  the  Audion. 
Mention  was  also  made  of  the  Audion  being 
used  to  check  various  measurements  owing 
to  the  high  per  cent,  of  its  efficiency  and 
almost  negligible  per  cent,  of  errors. 

The  subject  for  the  October  meeting  was 
"Radio  Telegraphy  in  Competition  with 
Wire  Telegraphy  in  Overland  Work"  by 
Robert  Boyd  Black.  U.S.N.R.F. 


the  spark  gap.  A  good  one  was  described 
in  a  previous  issue  of  this  magazine.  The 
core  of  this  coil  should  be  about  the  same 
size  as  the  leg  of  the  transformer. 

The  condenser  is  probably  the  source  of 
greatest  loss  in  the  amateur  station,  for 
most  of  them  seem  content  with  any  old 
kind  they  happen  to  think  of.  A  con- 
denser that  brushes  or  that  has  poor  con- 
nections loses  about  half  of  the 
energy  supplied  to  it.  Thin  sheet 
brass  makes  excellent  coatings  for 
the  plates  and  the  cost  is  not  pro- 
hibitive. The  lugs  should  be  one  inch 
or  more  wide  and  carefully  soldered 
to  the  plate.  The  series-parallel  con- 
nection should  be  employed  if  possi- 
ble, as  it  gives  almost  entire  freedom 
from  puncture  and  minimizes  brush 
losses.  Four  banks,  each  of  the 
capacity  required  for  the  trans- 
former, are  connected — two  in  series 
and  two  in  parallel.  As  each  section 
handles  only  one-fourth  of  the  volt- 
age, thin  glass  may  be  used.  The 
dielectric  strength  of  a  thin  dielectric 
is  much  greater  in  comparison  to  the 
voltage  required  to  puncture  it  than 
that  of  a  thick  dielectric.  Thus  the 
use  of  thinner  plates  allows  the  use 
of  a  fewer  number  with  the  same 
capacity.  Glass  losses  are  reduced 
in  this  way  also.  This  type  of  condenser 
when  immersed  in  a  good  grade  of  oil  gives 
excellent  satisfaction. 

High  frequency  resistance  is  much  greater 
for  short  wave  lengths  tban  for  long,  so 
the   amateur    is    handicapt   by   this  also. 


EFFICIENCY  IN  RADIO  TRANS- 
MITTING CIRCUITS. 
By  Bayard  Shumate. 

THE   efficiency   of   the  average  ama- 
teur radio  transmitter  is  very  low  and 
is  usually  due  to  carelessness  regard- 
ing small  details-,  rather  than  to  poor  in- 
struments. 

In  the  first  place  an  efficient  transformer 
costs  little  more  than  a  poor  one,  so  it  is 
advisable  to  purchase  it  from  a  reliable 
firm.  As  the  maximum  input  allowed  is 
only  1,000  watts,  as  little  energy  as  possi- 
ble should  be  lost  in  the  transformation. 
A  choke  coil  should  be  inserted  in  the  pri- 
mary circuit,  as  it  is  invaluable  in  close 
tuning  as  well  as  in  preventing  arcing  at 


This  Audion  Diagram  Represents  Another  Method 
of  Coupling  Inductively  the  Plate  and  Wing  Circuit. 
In  This  Case  Condenser  C,  Is  Shunted  Across  the 
Wing  Inductance  Permitting  Greater  Freedom  of 
Tuning  Grid  Current. 

The  frequency  of  an  oscillatory  current  at 
200  meters  is  enormous  (something  around 
1,500,000),  therefore  all  connections  must 
be  made  with  conductor  having  a  large 
surface.    Conductors  containing  50  to  100 
strands  of  No.  22  bare  wire,  twisted  to- 
gether,   are    commonly    used    but  heavy 
brass    strip    is    preferable    where  possi- 
ble.    Those  of  the  primary  circuit 
should  be  very  short  and  should  not 
exceed  20  inches.   The  condenser,  gap 
and  oscillation  transformer  can  read- 
ily be  arranged  to  allow  these  short 
leads.    The  transformer  may  be  set 
anywhere  and  the  current  may  be 
supplied  to  the  two  condenser  con- 
nections thru  small  wires  (No.  18  to 
22),  which  have  been  coiled  into  a 
spiral.     These    spirals    form  choke 
coils,  which  aid  in  preventing  arcing 
at  the  gap  and  prevent  kick-backs. 
(See  "E.E."  for  January.)     If  any 
conductor  heats  to  the  slightest  de- 
gree, it  should  be  replaced  by  a  larger 
one,  for  the  energy  lost  in  producing 
this  heat  means  many  miles  less  ef- 
fective range. 
Almost  any  standard  rotary  will  give 


good  service  if  it  is  not  run  too  fast.  It  is 
true  that  a  high  tone  is  more  audible  than 
a  low  one,  but  on  a  60  cycle  current  the 
condenser  cannot  be  properly  charged  when 
a  very  high  tone  is  used.  It  is  best  to  use 
a  medium  tone  so  as  to  combine  the  audi- 
bility of  the  higher  tone  with  the  powerful 
condenser  discharge  of  the  lower. 

The  oscillation  transformer  loses  energy 
due  to  the  inductive  coupling.  It  should 
then  be  large  enough  to  secure  a  proper 
transformation  of  energy  and  not  too  loose- 
ly coupled.  Three  inches  is  enough  for  a 
half  kilowatt  set  and  will  give  a  sharp 
wave  if  properly  handled.  A  sharp  wave 
depends  more  upon  resonance  than  upon 
coupling,  tho  a  sharp  wave  cannot  be  se- 
cured if  the  coupling  is  too  close.  A  good 
method  of  tuning  is  as  follows: — 

(1)  Connect  a  hot  wire  ammeter  in  the 
aerial  circuit,  set  the  coupling  at  about  4 
inches  and  connect  the  entire  secondary  in 
the  circuit. 

(2)  Adjust  the  primary  clips  until  the 
meter  shows  the  greatest  radiation. 

[Note:  If  more  than  two  turns  of  pri- 
mary ribbon  are  necessary  the  condenser  is 
too  small  and  must  be  enlarged  accord- 
ingly.] 

(3)  The  ammeter  is  now  removed  from 
the  circuit  as  it  damps  the  oscillations. 
The  set  is  then  tested  for  sharpness  with  a 
wave  meter.  This  need  not  be  an  expen- 
sive instrument.  About  twenty  turns  of 
insulated  wire  (18  to  20)  are  wound  on  a 
tube  4  or  5  inches  in  diameter  and  con- 
nected in  series  with  a  small  battery  lamp 
and  variable  condenser.  This  will  be  suf- 
ficient for  comparative  readings.  If  the 
lamp  lights  over  a  large  number  of  degrees 
on  the  condenser  scale,  the  wave  is  broad. 

Then  move  one  of  the  secondary  clips 
around  one  turn  of  ribbon,  a  little  at 
a  time,  until  the  lamp  will  light  over 
ten  or  fifteen  degrees  only.  If  the 
wave  cannot  be  tuned  sharply  by  this 
means,  the  coupling  is  too  close  and 
must  be  moved  back.  If  the  wave  is 
found  to  be  sharp,  the  coupling  may 
be  tightened  until  it  begins  to  broaden 
a  bit.  If  it  can  be  sharpened  again 
at  this  point  it  will  be  to  advantage. 
The  point  is  to  get  the  wave  sharp 
with  the  coupling  as  close  as  possible. 
A  sharp  wave  is  advisable  for  long 
distance  work  because  no  energy  is 
wasted  in  the  waves  aside  from  the 
one  affecting  the  receiving  station. 

The  aerial   conductors   should  be 
stranded  if  possible  and  of  course  as 
high  as  possible.  They  should  not  be 
over  110  feet  in  total  length  to  have 
a  200  meter  wave.    The  wires  should 
be  widely  spaced  as  a  few  wires  widely 
separated  have  a  larger  capacity  than  many 
wires  close  together. 

Thus  efficiency  results  from  careful  at- 
tention to  small  details,  for  if  a  single  de- 
tail is  slighted  it  means  the  loss  of  energy 
— something  that  the  amateur  has  little 
enough  of  to  start  with. 


5  C— 

=  f 

c7 

Diagram  3  Shows  a  Method  by  Which  Plate  and 
Wing    Units    Are    Coupled    Electrostatically  Thru 
Condensers  Cg  and  Cp. 


November,  1917 


THE  ELECTRICAL  EXPERIMENTER 


467 


m  <2N5TRVIQTER 


Construction  of  a  Laboratory  Vacuum  Pump 

By  RAYMOND  FRANCIS  YATES 


A GOOD  vacuum  pump  should  be  in- 
cluded in  the  equipment  of  every 
laboratory,  but,  owing  to  the  pro- 
hibitive price  of  such  machines,  the 
experimenter  generally  finds  it  im- 
possible to  purchase  one.    The  following 


Appearance  of  Finished  Vacuum  Pump, 
Details  for  Constructing  Which  Are  Given 
Herewith. 


paragraphs  describe  the  construction  of  a 
pump  that  is  capable  of  creating  a  vacuum 
as  high  as  l/l,000,000th  of  an  atmosphere 
(equivalent  to  .00003  inch  of  mercury). 
The  total  cost  of  construction  should  not 
exceed  $3  including  the  22  ounces  of  mer- 
cury necessary  to  operate  it. 


The  principle  upon  which  the  pump 
works  was  first  discovered  by  Torricelli, 
and  Geissler  of  Bonn,  Germany,  was  the 
first  inventor  of  an  apparatus  utilizing  the 
Torricellian  principle  for  creating  high 
vacua  in  enclosed  vessels.  Geissler's  va- 
cuum pump,  however,  was  very  complicated 
and  somewhat  costly  and  Dr.  Sprengel  later 
made  many  improvements  on  it,  not  only 
making  it  more  convenient  for  the  labora- 
tory, but  increasing  its  efficiency  and  mak- 
ing it  much  easier  to  manipulate. 

Before  starting  the  actual  construction 
of  the  pump,  it  is  advisable  that  the  builder 
become  sufficiently  acquainted  with  its 
theory  of  operation  to  proceed  in  making 
the  various  necessary  parts  in  an  intelligent 
manner.  The  experimenter,  Torricelli,  dis- 
covered that  a  column  of  mercury  passing 
thru  a  tube  with  a  small  bore  pushed  the 
air  in  the  tube  before  it  and  left  a  vacuum 
in  its  wake,  providing  one  end  of  the  tube 
was  closed  to  prevent  the  re-entrance  of 
air.  Referring  to  Fig.  1,  it  will  be  seen 
that  a  small  column  of  mercury  passing 
down  the  long  glass  tube  "C"  will  act  as  a 
piston  and  push  the  air  before  it  into  the 
automatic  valve  "H",  which  permits  the 
air  to  leave  but  makes  it  impossible  for  it 
to  re-enter.  The  passage  of  the  mercury 
from  the  reservoir  into  the  tube  is  con- 
trolled by  the  valve  "B"  and  the  vessel  to 
be  evacuated  is  connected  to  the  glass  tee 
"L". 

The  automatic  valve  is  shown  in  detail  in 
Fig.  2.  With  a  little  study  it  will  be  seen 
that  when  the  test  tube  is  filled  with  mer- 
cury air  may  escape  from  the  glass  tube 
thru  the  small  hole  but  the  mercury 
prevents  the  air  on  the  outside  from  re- 
entering. Every  time  mercury  is  dropt 
thru  the  long  glass  tube  "C"  the  air  in  the 
vessel  "S"  becomes  more  rare  until  it  is 
reduced  to  an  infinitesimal  fraction  of  its 
original  value.  From  20  to  30  minutes 
operation  will  produce  a  very  high  vacuum 
in  a  vessel  with  a  capacity  under  .5  of  a 
liter.  When  the  air  in  the  vessel  "S" 
reaches  a  small  value,  the  mercury  in  the 
tube  "C"  mounts  to  the  barometric  height 
of  approximately  30  inches. 

The  first  material  required  is  the  stan- 
dard on  which  to  mount  the  long  glass 
tube,  and  a  base.  These  are  cut  from  quar- 
tered oak.  The  base  is  9  x  9  x  1"  and  the 
standard  is  M  x  l1/  x  36".  Both  should 
be  cut  accurately  and  sandpapered.  A 
notch  is  then  cut  in  the  top  of  the  standard 
as  shown :  this  is  to  accommodate  the  glass 
funnel  which  holds  the  mercury.  After 
this,  the  base  and  the  standard  may  be 
varnished.  Obtain  two  brass  angles  and 
fasten  them  to  the  standard  as  shown.  The 
glass  tube  should  be  about  31"  long  with  a 
bore  not  exceeding  3/32".  The  tube  is 
fastened  to  the  standard  by  means  of  four 
small  brass  staples  as  shown  in  Fig.  3. 
Care  should  be  exercised  in  screwing  the 
staples  to  the  standard  as  the  glass  tube 
will  crack  if  pinched  too  tightly.  After 


mounting  the  tube,  the  standard  should  be 
fastened  to  the  base  by  means  of  the  brass 
angles.  Owing  to  the  inability  of  the  angles 
to  hold  the  standard  rigidly  because  of  its 
height,  it  will  be  found  necessary  to  pro- 
vide a  brace  at  the  back  of  the  standard. 
This  is  shown  in  Fig.  4.  The  brass  rod 
should  be  about  18"  long.  A  glass  funnel 
about  3"  in  diameter  should  be  purchased 
and  its  stem  reduced  to  about  %  of  an  inch 
by  grinding  it  on  the  corner  of  an  emery 
wheel  and  breaking  the  larger  portion  off. 
The  funnel  is  then  mounted  on  the  top  of 
the  standard  by  means  of  a  small  brass 
staple.  The  funnel  is  so  fastened  to  the 
top  of  the  standard  that  it  will  rest  in  the 
notch  previously  cut.  Such  procedure  is 
absolutely  necessary  owing  to  the  great 
weight  of  the  mercury  in  the  funnel. 

The  glass  tee  should  have  a  bore  about 
the  same  size  as  that  of  the  large  tube. 
Such  tees  may  be  purchased  from  any 
chemical  supply  house  for  a  few  cents  and 
the  writer  would  not  advise  any  builder 
to  attempt  to  make  one  unless  he  is  thoroly 
experienced  in  glass  blowing.  The  tee 
should  be  connected  to  the  end  of  the 
funnel  and  the  long  glass  tube  by  means  of 
heavy  rubber  tubing  just  large  enough  to 
fit  snugly  over  the  top  of  the  glass.  Be- 


Important  Features  of  Ideal  Mercury  Vac- 
uum Pump  for  the  Experimenter,  Includ- 
ing Details  of  Automatic  Over-flow  Valve. 


468 


THE  ELECTRICAL  EXPERIMENTER 


November,  1917 


fore  the  rubber  tubing  is  put  on,  the  glass 
should  be  smeared  with  a  thin  layer  of 
vaseline.  After  the  rubber  tube  is  put  on, 
black  thread  is  wound  tightly  around  each 


Valve  Mounted  Jf 


Nut  Fig.  S 
u  J 


I  Brace* 


It 

i 

- 

m 

o 

M 

o 

Method  of  M 
cutting  notch  ■ 


Side  View  of  Home-made  Mercury  Vac- 
uum Pump  Which  Is  Suitable  for  Exhaust- 
ing Geissler  Tubes,  X-ray  Bulbs,  Lamps, 
Coherers,  and  a  Host  of  Other  Things  Dear 
to   Every   Experimenter's  Heart. 


joint  and  another  application  of  vaseline  is 
smeared  over  the  thread  and  joint.  This 
procedure  produces  a  joint  that  is  very 
near  to  being  absolutely  air-tight  and  such 
joints  are  positively  necessary  to  the  suc- 
cessful operation  of  the  pump. 

The  little  valve  at  "B"  was  developed  by 
the  writer  and  is  simplicity  in  itself.  It  is 
shown  in  detail  in  Fig.  5.  By  pressing  the 
knob,  the  pressure  of  the  arm  on  the  tubing 
is  overcome  and  mercury  is  permitted  to 
flow  (for  a  fraction  of  a  second)  from  the 
funnel  into  the  tube.  Releasing  the  pres- 
sure causes  the  spring  to  bring  the  arm 
back  to  its  original  position  where  it  pinches 
the  rubber  together  and  prevents  the  flow 
of  mercury.  When  the  pump  is  not 
in  use,  the  arm  should  be  turned  so  it 
•will  not  come  to  rest  upon  the  rubber 
tube  as  permanent  pressure  will 
injure  the  tubing. 

To  indicate  the  degree  of  vacuum 
attained  at  any  stage  of  the  opera- 
tion, it  will  be  necessary  to  make  a 
suitable  scale  on  the  standard  at  the 
side  of  the  long  glass  tube.  The 
lines  are  drawn  ^4"  apart  and  after 
marking  them  with  a  soft  pencil  the 
lines  should  be  painted  over  with 
white  "show-card"  ink  applied  with 
a  very  small  brush.  Such  a  scale 
stands  out  prominently  and  adds  to 
the  appearance  of  the  instrument 
considerably. 

When  the  pump  is  operated,  the 
vessel  to  be  evacuated  should  not  be 
connected  to  the  tee  by  means  of  a 
long  rubber  tube  as  the  tube  will  be 
pressed  together  by  the  atmospheric 
pressure  on  the  exterior  (14.7  lbs.  to 
the  square  inch)  and  the  further 
passage  of  air  from  the  vessel  will  be  in- 
terfered '  with  if  not  altogether  prevented. 
This  difficulty  can  be  overcome  by  using 


glass  tubing  with  small  pieces  of  rubber  at 
the  joints  to  produce  flexibility.  All  joints 
should  be  prepared  according  to  the  pre- 
ceding directions. 

When  the  pump  is  operating  properly, 
the  mercury  will  fall  thru  the  long  glass 
tube  in  separate  little  columns  and  each 
column  acts  as  a  piston  pushing  air  before 
it.  The  valve  at  the  top  of  the  standard 
should  be  manipulated  intermittently  until 
the  mercury  in  the  tube  rises  to  about  30 
inches.  This  will  indicate  a  vacuum  suffi- 
ciently high  for  ordinary  purposes. 

A  small  receptacle  is  placed  under  the 
hole  in  the  test  tube  to  receive  the  mercury 
as  it  overflows.  When  the  receptacle  is 
full,  the  mercury  is  poured  back  into  the 
funnel.  Do  not  permit  all  the  mercury  in 
the  funnel  to  run  out  as  this  will  destroy 
the  vacuum. 


REGARDING  TESLA  AND  OUDIN 
COILS. 
By  Carl  H.  Rauschenberg 

Experimental  Engineer 
I  present  herewith  two  photos  illustrating 
my  cone-shaped  high-frequency  coil  in  op- 
eration. The  photo  Fig.  1  shows  the  enor- 
mous brush  discharge  from  a  wire  attached 
to  the  upper  terminal  and  also  the  discharge 
from  top  of  coil.  The  photo  Fig.  2  shows 
the  spark  discharge  from  a  ball  terminal 
placed  on  top  of  the  coil  to  a  grounded 
conductor. 

This  coil  is  very  similar  to  one  described 
in  the  "E.  E."  a  short  time  ago  (see  May, 
1917,  issue).  It  was  excited  by  a  %  K.  W. 
Thordarson  Type-T  transformer  and  an 
oil  immersed  condenser  of  about  .008  M.  F. 
using  small  8-stud  rotary  gap  running  at 
5,000  R.  P.  M. 

The  building  of  the  coil  was  not  so  diffi- 
cult, the  method  of  building  the  secondary 
cylinder  being  somewhat  different  from 
usual  practise.  I  went  to  a  tinshop  and 
told  them  to  make  me  a  cone  of  heavy  gal- 
vanized-iron  15"  dia.  at  bottom,  7"  at  top 
and  20"  high;  seamed  on  the  inside.  This 
gave  a  perfectly  smooth  outside  surface.  I 
set  this  form  on  a  table  and  cut  large  pieces 
of  ordinary  building  paper  of  a  shape  to 
fit  around  it.  I  just  merely  built  up  the 
paper  using  ordinary  glue  until  I  had  a 
thickness  of  about  Y%" .  The  paper  can  be 
cut  so  that  it  will  fit  the  cylinder  perfectly. 
The  best  method  is  to  watch  the  tinner  cut 
out  the  iron  for  the  cone,  take  the  dimen- 
sions he  uses  and  cut  your  paper  the  same 
way.  If  the  first  piece  of  paper  is  cut  the 
same  size  as  the  tinner  cuts  the  metal  it 
will  be  found  to  overlap  slightly  when  fitted 
around  the  coil.    This  is  as  it  should  be 


first  sheet  is  in  place  cut  another  sheet  to 
the  same  dimensions  and  trim  the  edges  till 
they  just  meet,  fitting  the  paper  before 
applying  glue.  Spread  the  sheet  of  paper 
on  the  floor,  give  it  a  thin  coat  of  hot  glue 
and  quickly  apply  it  to  the  form.  Continue 


Fig 
Disc 


2.     Showing  the  Powerful   High  Frequency 
harge   From  a   Ball  Terminal   on  Oudin  Coil 
Grounded  Conductor. 


and  glue  should  only  be  put  on  the  lap  so 
that  the  paper  is  not  glued  to  the  form 
which  must  be  removed  later.    After  the 


Fig.    1.     Illustrating   the   Vigorous  High 
Frequency  Discharge  From  Free  Electrode, 
As  Well  As  Top,  of  Oudin   Coil  of  Good 
Design. 

in  this  way  until  the  desired  thickness  is 
attained.  About  10  to  12  sheets  will  be  suffi- 
cient. The  joints  should  be  staggered  at 
various  intervals  around  the  cylinder  of 
course.  Leave  the  paper  on  the  form  for 
48  hours  or  until  perfectly  dry  and  hard. 
Remove  and  give  two  coats  of  shellac  in- 
side and  outside. 

The  winding  was  done  in  the  usual  way 
using  a  string  to  space  the  turns  and  the 
finished  winding  given  5  coats  of  shellac 
to  insulate  it  and  hold  it  in  place.  The  size 
of  wire  is  not  so  important,  mine  being 
wound  with  27  D.C.C.  wire.  Enameled 
wire  should  not  be  used. 

Primary  consists  of  4  turns  of  copper 
ribbon,        wide  wound  into  a  spiral  with 
a  thickness  of  ordinary  corrugated  paste- 
board (cut  from  a  bread  carton  secured  at 
a  local  grocery),  between  the  turns. 
Primary  leads  are  connected  to  bind- 
ing posts  leading  to  ends  of  primary 
ribbon ;  thus  the  entire  4  turns  are 
always  in  circuit,  tuning  being  ac- 
complished with  the  secondary  of  a 
wireless  oscillation  transformer  which 
is  placed  in  series  with  condenser, 
spark  gap  and  primary  of  Oudin  coil ; 
the  wiring  diagram  shown  in  "E.  E." 
several  months  ago  being  used. 

I  find  the  spark  length  from  the 
Oudin  type  of  coil  to  be  not  so  long 
as  that  from  the  Tesla  type  with  a 
given  amount  of  power,  but  much 
heavier  and  capable  of  experiments 
not  possible  with  Tesla  type. 

Some  wonderful  results  can  be  had 
from  the  ordinary  wireless  sending 
set  and  in  my  opinion  no  amateur 
will  regret  the  time  and  money  spent 
in  the  building  of  a  coil  for  use  on 
his  sending  set. 


Spark 
to  a 


Due  to  the  advent  of  the  war,  we 
are  particularly  desirous  of  obtaining 
snappy  manuscripts  describing  original 
and  practical  "Electrical  Experiments." 


November,  1917 


THE  ELECTRICAL  EXPERIMENTER 


469 


A  SHOCKING  ELECTRIC  ALARM 
FOR  COMMUTERS. 

We  all  have  made  and  used  at  one  time 
or  another  some  form  of  that  torturing  de- 
vice known  as  The  Early  Riser's  Alarm. 
At  first  the  regular  electric  bell  was  suffi- 
cient to  rouse  us  out  of  bed  in  time  to 
catch  the  early  train,  but  it  soon  lost  its 
wakening  powers  with  the  result  that  a 
hundred  yard  dash  was  necessary  to  get 
even  the  late  train.  We  then  installed  an 
electric  horn  made  from  a  tin  can  and  a 
bell.  That  worked  fine  for  a  time  and  then 
it  failed  to  give  us  that  sudden  shock  that 
should  accompany  our  awakening  to  get  us 
out  of  bed  immediately.  We  had  gotten 
used  to  the  racket  and  could  not  increase  it 
any  without  bringing  down  the  wrath  of  the 
neighbors. 

The  writer  tried  them  all,  even  consid- 
ered the  use  of  a  small  cannon  or  a  device 
to  pull  one  leg  from  under  the  bed  but 
dropt  them  all  in  favor  of  the  scheme  de- 
scribed here. 

The  clock  used  possest  no  original  fea- 
tures but  its  simplicity  may  be  of  interest. 
Examining  Fig.  1,  it  will  be  seen  that  a 
block  of  wood  was  mounted  just  below  the 
winding  key  for  the  alarm.  A  strip  of 
%  inch  brass  was  fastened  to  the  block  in 
such  a  way  as  to  prevent  the  key  making 
more  than  a  quarter  turn  when  the  alarm 
went  off.  Wires  were  connected  to  the 
insulated  strip  and  to  the  framework  of  the 
clock.  It  was  then  a  simple  matter  to  set 
the  alarm  and  it  was  likewise  necessary  to 
arise  to  turn  it  off  in  the  morning.  A 
switch  may  of  course  be  included  but  it  is 
unnecessary;  you  will  get  up  anyway. 

The  other  parts  consist  of  several  dry 
cells,  a  buzzer,  a  small  induction  coil  (a 
J4  inch  spark  coil  or  a  telephone  induction 
coil  will  do)  and  two  strips  of  tinfoil  3  or  4 
inches  wide  and  2  feet  long. 

These  are  wired  according  to  the  diagram 
in  cut;  the  buzzer  being  unnecessary 
when  the  usual  spark  coil  is  employed. 
The  tinfoil  strips  are  laid  under  the  sheet 
on  the  bed  and  separated  a  distance  of 
about  three  feet. 

Now  let  us  see  what  happens  when  "Big 
Ben"  closes  the  switch.  The  buzzer  will 
interrupt  the  circuit,  causing  high  voltage 
currents  in  the  secondary  circuit  that  find 
a  path  thru  the  innocent  sleeper's  body  by 
jumping  thru  the  thin  sheet  that  separates 
him  from  the  tinfoil  electrodes.  It  is 
borne  forcibly  on  him  that  his  presence  is 
not  desired  any  longer.  A  departure  un- 
der such  circumstances  is  accepted  as  the 
usual  thing  by  most  persons,  who  will  then 
start  the  day  with  zest  and  vigor. 

Try  this,  "Bugs,"  it  won't  hurt  you. 

Contributed  by  THOS.  W.  BENSON. 


LIGHT  CONTROLLED  BY  OPEN- 
ING AND  CLOSING  DOOR. 


Tin  fori  5 f rips 

4 I  arm  winding  key 
■  Brass  sTr/p 

Buzzer 


Alorm 
C/ocA 


Telephone 
'  coif 


-gait 


ft 


Are  You  a  Commuter?  An  Ingenious  Experi- 
menter Has  Perfected  a  Sure-Fire  Electric 
Ejector  for  All  Such.  Simply  Connect  the 
Circuit-Closer  to  Your  Clock;  Hook  Up  a 
Buzzer,  and  Telephone  Induction  Coil  as 
Shown  and  Also  Two  Tinfoil  Strips,  Laid 
Under  the  Sheet.  When  5  A.  M.  Arrives,  You 
Will  Awaken — Never  Fear. 


occasion  to  install 
cellar  closet  used 


Te/JacA 


Not  long  ago  I  had 
an  electric  light  in  a 
for  storing  veg- 
etables. It  was  im- 
portant to  keep  the 
door  of  this  closet 
open  as  little  as  pos- 
sible, that  the  tem- 
perature might  be 
kept  as  low  as  pos- 
sible, and  for  this 
purpose  the  door 
was  closed  by  a 
weight  and  rope  ar- 
rangement. More- 
over, servants  were 
frequently  obliged 
to  enter  or  leave  the 
closet  with  both 
hands  full.  It  was 
therefore  necessary 
to  install  a  light 
which  would  be  au- 
tomatic in  action, 
and  would  not  re- 
quire the  door  to  be 
kept  open  while  the 
light  was  burning, 
as  is  the  case  with 
several  of  the  auto- 
matic door  switches  now  on  the  market. 

All  these  difficulties  were  met  at  once  in 
a  very  simple  manner.  A  common  pull 
socket  was  installed,  and  the  chain  of  the 


also  to  fill  the  closet  with  warm  air.  The 
whole  apparatus  consists  of  an  ordinary 
chain-pull  socket  and  a  piece  of  cord,  thus 
obviating  the  mortises  necessary  in  the  ordi- 
nary door-switch,  and  making  a  very  much 


insulator 


Buzzer'*—*   Tel.  cord  &  plug  (g 


By  Employing  a  Telephone  Jack  Switch  as  Shown,  It  Is  Possible 
to  Disconnect  the  Electric  Alarm  Attachment  from  the  Clock  In- 
stantly.   A  Very  Desirable  Feature. 


simpler  and  cheaper  installation. 
Contributed  by  THOMAS  T.  HOOPES. 


It  Is  Often  Desired  to  Have  a  Door  Control 
a  Lamp,  Such  as  in  Cellars,  Garrets,  Etc. 
By  Attaching  a  String  and  Counterweight  to 
a  Chain-Pull  Socket,  the  Problem  Is  Solved. 


socket  was  connected  by  a  cord  with  the 
weight  used  to  close  the  door,  in  such  a 
way  that  when  the  weight  was  as  near 
the  floor  as  it  could  go,  and  when  there- 
fore, the  door  was  closed  all  the  way,  the 
cord  was  pulled  taut,  and  the  chain  with 
it.  The  result  of  this  was,  that  when  the 
door  was  opened,  the  weight  was  raised, 
the  cord  loosened,  and  the  spring  of  the 
socket  drew  the  ratchet  back,  engaging  the 
switch ;  when  the  weight  pulled  the  door 
to  again,  the  cord  was  again  tautened,  the 
switch  operated,  and  the  lamp  lighted. 

The  results  of  this  arrangement  were 
these :  The  switch  was  entirely  automatic, 
being  operated  by  the  opening  and  clos- 
ing of  the  door.  When  one  enters  the 
closet,  the  light  is  lighted,  when  one  leaves, 
it  is  extinguished.  The  light  is  not  turned 
on  until  the  door  is  closed,  so  there  is  no 
inducement  to  leave  it  propt  open,  to  save 
trouble  in  opening  with  the  hands  full,  but 


USING  TELEPHONE  JACK  TO 
CONNECT  ALARM  CLOCK. 

Having  seen  a  number  of  electric  alarm 
clocks  of  many  fearful  as  well  as  ingenious 
designs  in  the  "E.E.",  including  the  one 
in  the  January  number,  I  show  above 
for  approval  one  that  I  have  had  in  use 
for  over  a  year  with  excellent  results. 
Most  of  those  previously  publisht  make 
contact  when  the  alarm  spring  unwinds. 
In  the  clock  I  have,  the  winding  spindle 
does  not  turn  when  the  spring  unwinds. 
The  arrangement  I  have  differs  from  those 
previously  described,  as  it  does  not  depend 
on  the  alarm  spring.  The  clock  is  separate 
from  the  rest  of  the  circuit  and  may  be 
used  elsewhere  when  the  alarm  is  not 
needed.  When  the  alarm  is  wanted,  simply 
hang  the  clock  upon  a  hook  and  insert 
the  plug  in  the  telephone  jack  mounted  on 
the  back  of  the  clock.  Place  the  alarm 
contact  on  the  dial  at  the  hour  desired. 
The  battery  may  be  placed  in  the  attic  or 
cellar,  the  wire  fished  thru  the  partitions, 
and  brought  out  at  the  binding  posts. 
Mount  the  buzzer  and  telephone  cord  as 
per  drawing;  connect  one  lug  of  the  jack 
to  the  frame  of  the  clock,  the  other  to 
a  ring  made  from  a  shade  holder  in  the 
front  and  insulated  from  the  clock  by 
three  small  fiber  blocks.  When  the  hour 
hand  comes  in  contact  with  the  alarm  con- 
tact,  the  buzzer  operates. 

Contributed  by     HOWARD  D.  DYE. 


RENEWING  DRY  CELLS. 

I  have  been  experimenting  with  dry  bat- 
teries for  over  a  year,  to  find  a  renewing 
solution  and  I  have  kept  a  worn  out  dry 
dry  battery  alive  with  the  following  solu- 
tion, for  over  six  months : 

Hydrochloric  acid,  12  ounces. 

Add  scrap  zinc  till  acid  stops  boiling; 
use  earthen  jar. 

The  sealing  wax  is  to  be  removed  from 
top  of  dry  of  battery,  the  loose  carbon 
surrounding  the  carbon  proper  is  to  be 
loosened  (an  ice  pick  will  do  this)  and  the 
acid  solution  poured  in  till  the  loose  carbon 
is  thoroly  wet,  but  not  muddy.  The  battery 
is  then  resealed,  and  is  ready  for  immediate 
use. 

Contributed  by  JOHN  BLACKHURST. 


470 


THE  ELECTRICAL  EXPERIMENTER 


November,  1917 


A  HOME-MADE  CODE-LEARNER. 

Figure  1  shows  the  base  and  the  dimen- 
sions are  left  to  the  builder.  The  wooden 
ring  should  be  about  I4"  thick  and 
wide.  A  is  a  brass  or  copper  strip 
sunk  even  with  the  surface  of  the  ring ; 
it  is  fastened  inside  with  a  screw  and  out- 
side with  a  binding  post  for  connection. 
B  is  a  binding  post  with  two  holes,  one  for 
a  connection,  and  the  top  one  for  a  strip 


Home-made    Code    Transmitter  Constructed 
from  Cardboard  Disc,  a  Hand  Crank  to  Turn 
it  with  and  a  Contact  Spring  Which  Closes 
the  Sounder  or  Buzzer  Circuit. 

of  brass  or  copper  pressing  on  A  to  make 
contact.  C  is  the  base  to  which  the  wooden 
ring  D  is  glued.  Fig.  2  is  a  side  view  of 
the  machine.  "E"  is  a  brass  rod  in  the 
center  of  the  ring,  over  which  the  disk 
(Fig.  4)  and  the  crank  (Fig.  3)  slip.  Fig. 
3  shows  the  crank,  which  is  about  ^4"  wide 
with  holes  bored  in  so  as  to  slip  over  E. 
Fig.  4  is  the  disk  which  is  made  of  thin 
cardboard  with  the  dots  and  dashes  cut 
out  as  shown.  Connections  are  taken  off 
at  the  two  binding  posts  and  connected  to 
a  battery  and  buzzer. 
Contributed  bv 

FRANKLIN  McTAVISH. 


REMOVAL  OF  INK  STAINS. 

The  tartaric  acid  and  citric  acid  ink  re- 
mover combination  leaves  a  yellow  stain.  It 
affects  only  fresh  stains  appreciably,  and 
even  then  does  not  remove  them  well  at  all. 

The  only  method  that  I  have  found  satis- 
factory for  fresh  stains  on  paper,  is  the 
following  two  solution  remover,  the  con- 
centration of  which  may  be  varied  in  in- 
dividual cases.  Two  parts  of  concentrated 
borax  solution  are  dissolved  in  ten  parts  of 
water  and  one  part  of  citric  acid  added, 
this  forms  the  first  solution.  The  second 
solution  consists  of  three  parts  of  calcium 
chlorid,  ten  parts  water,  two  parts  of  con- 
centrated borax  solution.  The  calcium 
chlorid  should  be  dissolved  in  the  water, 
the  mixture  set  aside  for  a  few  days  and 
only  the  clear  supernatant  liquid  used. 

The  first  solution  is  generously  applied, 
the  excess  removed,  and  the  second  ap- 
plied. The  spot  should  finally  be  washed 
with  water. 

Contributed  by  J.  FIERSTEIN. 


AN  EXTREMELY  SENSITIVE 
MICROPHONE. 

The  writer  recently  conducted  some  ex- 
periments  in   an   attempt   to   construct  a 
simple  and  compact  microphone  that  would 
be     extremely  sensitive. 
The   result  of   his  work 
along  this  line  is  shown  in 
the  illustration. 

A  microphone  trans- 
mitter was  obtained  and 
arranged  to  be  mounted  on 
the  back  of  a  shallow  box 
just  a  little  larger.  The 
transmitter  was  of  a  re- 
cent type  having  a  metal 
diafram  with  an  insulated 
carbon  button  attached  to 
the  center.  A  carbon  dia- 
fram transmitter  cannot 
be  used  very  satisfactorily. 

The  nut  was  removed 
from  the  center  of  the  dia- 
fram and  a  piece  of  brass 
rod  one  inch  long  and  ^4 
inch  in  diameter  was 
drilled  lengthwise  and  tapt 
with  a  No.  8-32  thread.  A 
washer  y2  inch  in  diam- 
eter was  soldered  to  both 
ends  of  this  rod  as  shown 
in  the  detail  drawing  at 
B,  C,  and  F. 

After  substituting  a 
mica  diafram  for  the  metal 
one  the  parts  were  reas- 
sembled with  the  short 
threaded  brass  rod  instead 
of  the  nut  in  the  center  of 
the  diafram. 

A  4-inch  disk  of  mica 
was  then  cut  and  by  means 
of  a  small  8-32  screw  and 
a  washer  fastened  to  the 
brass  rod.  The  whole  de- 
vice was  then  placed  in  the 
box  and  connections  made 
to  the  transmitter  in  the 
usual  manner. 

The  front  of  the  box 
was  pierced  with  a  large 
number  of  holes  inch 
in  diameter. 

When  properly  made  and  assembled  this 
device  is  very  sensitive  and  will  pick  up  the 
faintest  sound.  A  method  for  testing  the 
sensitiveness  of  such  microphones  that  was 
found  of  value  by  the  writer  is  to  connect 
them  in  series  with  a  receiver  and  battery 
and  note  the  distance  they  can  be  held  apart 
and  still  act  on  one  another.  The  receiver 
and  transmitter  should  first  be  brought  close 


COMBINED  CALL  BELL,  FIRE  AND 
BURGLAR  ALARM  SYSTEM. 

The  scheme  given  herewith  is  to  con- 
nect an  ordinary  four-drop  annunciator,  so 
that  it  may  be  used  for  a  call  bell,  burglar 


Bell 


Common  Contact 


„  -Battery        T     T      T  T 
Interior  Circuit  of  Annunciator 

-ci;  Single  Stroke  4' 'Burglar Alarm 

Extension  Bell  r^t""Be/l 

8"Fire  Alarm' 
Bell 


Zi  "Annunciator 
.■Bell 


U 


Constant 
Ringing 
Device 


t 


~~l  Push 
^Button 


I'L 


Q  Thermostat^ 


Burglar  Alarm  Spring 


Reconstructed    Microphone    Possessing  Ex- 
treme Sensitivity.     Suitable  for  Dictagraph 
Purposes. 

together  and  when  they  whistle,  separate 
them  slowly,  noting  the  distance  between 
them  when  the  note  ceases.  This  instru- 
ment will  give  an  audible  note  when  2  feet 
from  the  receiver  with  four  volts. 

Contributed  by    THOMAS  BENSON. 


Hook-up  for   Combined    Call    Bell,    Fire   and    Burglar  Alarm 
System  with  Centralized  Battery. 

alarm  and  a  fire  alarm  system  simultane- 
ously, to  give  location  of  call,  etc.,  in  all 
cases,  and  a  constant  ring  for  the  burglar 
and  fire  alarm,  and  one  extension  bell  to 
operate  only  from  the  front  door,  the  bell 
on  the  annunciator  operating  also ;  if  any 
other  button  is  prest  only  the  bell  on  the 
annunciator  operates. 

This  is  accomplisht  by  disconnecting 
the  bell  from  the  common  wire  which  con- 
nects to  the  drops,  and  connecting  the  bat- 
tery direct  to  this  common  connection. 
The  opposite  terminal  of  the  battery  con- 
nects to  all  bells,  and  the  other  side  of  bell 
acts  as  a  feed  wire  for  its  particular  sys- 
tem. A  ringing  device  is  used  to  give  a 
constant  ring  on  the  burglar  alarm  systems, 
while  the  ordinary  paraffin  thermostats, 
which  remain  closed  after  paraffin  has 
melted,  serve  to  give  a  constant  ring  on 
fire  alarm  system.  To  get  satisfactory 
operation  on  extension  bell  from  the  front 
door,  a  single  stroke  bell  must  be  used ; 
this,  however, 'will  operate  as  a  vibrating 
bell  due  to  the  make-and-break  of  contact 
at  the  vibrating  bell,  which  is  in  series  with 
it.  If  a  strong  battery  is  used  or  a  bell 
ringing  transformer,  two  vibrating  bells 
mav  be  used  on  parallel. 
Contributed  by  THOMAS  J.  HAYDEN. 


Due  to  the  advent  of  the  war,  we  are 
particularly  desirious  of  obtaining  manu- 
scripts describing  original  and  practical 
"Electrical  Experiments."  We  shall  con- 
tinue to  publish  Radio  articles,  but  what  we 
need  is  snappy  "Electrical"  articles. 


November,  1917 


THE  ELECTRICAL  EXPERIMENTER 


471 


HOW  TO  MAKE  AN  ELECTRIC 
FIRELESS  COOKER. 

A  "Fireless  Cooker"  finds  an  important 
place  in  every  home,  especially  one  that 


fVood 


CorA 


dsbesfo. 


Why  Not  Build  an  "Electric  Fireless  Cooker?" 
Two  Ordinary  Bricks  Wound  with  Resistance 
Wire,  Form  the  Heating  Unit  to  Start  the 
Food  Cooking.  Don't  Let  Any  of  the  Cork 
Get  in  Contact  with  the   Heater  Wire. 


is  operated  by  electricity.  The  one  that 
I  am  going  to  describe  can  be  built  very 
cheaply,  for  the  material  used  in  its  con- 
struction is  found  in  almost  every  home. 

The  cabinet  is  made  of  wood  16x16x18 
(quarter-sawed  oak  Y*  in.  thick  is  the  best). 
The  inside  is '  lined  with  about  *4  incn 
asbestos  sheeting.  Two  ordinary  house 
bricks  are  each  wrapt  with  several  feet 
of  No.  26  Nichrome  resistance  wire. 
These  two  bricks  are  then  covered  with 
asbestos  and  put  in  the  bottom  of  the 
cabinet.  From  one  end  of  Nichrome  wire 
on  brick  (b1),  a  copper  wire  is  connected 
by  twisting  (not  soldered).  This  wire  is 
connected  to  one  terminal  of  switch  (A). 
The  other  terminal  of  the  switch  is  con- 
nected to  one  of  the  flexible  wires.  The 
other  wire  (P)  is  connected  to  the  other 
end  of  the  resistance  wire.  Another  sheet 
of  asbestos  is  placed  over  the  brick.  On 
top  of  this  a  large  tin  bucket  is  placed, 
after  being  covered  by  asbestos  sheeting 
on  the  outside.  (A  lard  bucket  is  very 
good.)  The  space  between  the  bucket  and 
the  cabinet  is  now  to  be  filled  with  ground 
cork,  such  as  grapes  are  packed  in.  This 
is  clearly  understood  by  looking  at  sketch. 
Next  put  a  cover  over  this  so  that  the 
only  thing  you  will  be  able  to  see  is  the 
inside  of  the  bucket.  A  thick  lid  is  now 
made  for  the  cabinet  with  a  catch  at  the 
front  to  keep  it  tightly  closed.  When  you 
want  to  cook  something,  place  it  in  a  pot 
that  will  fit  in  the  bucket.  Turn  the  current 
on  by  switch  (A).  This  will  make  the 
bricks  hot.  These  bricks  will  give  off  heat 
for  a  great  while,  thus  saving  current  and 
money. 

Contributed  by  CHARLES  FENSKY. 


EXHAUSTING  BULBS  BY  MEANS 
OF  LIQUID  AIR. 

Those  who  are  intending  to  take  up  re- 
search work  as  their  career,  will  find  im- 
mense value  in  the  study  of  vacuum  tubes 
as  used  in  electrical  science,  especially  in 
the  radio  art. 

The  great  difficulty  encountered  with  such 
devices  is  the  production  of  sufficiently  high 
vacua  in  the  vessels  and  the  necessity  of 
expensive  apparatus  for  this  purpose,  which 
naturally  prohibits  the  average  individual 
from  investigating  the  above-named  con- 
trivances. 

Liquid  air  has  played  an  important  role 
in  the  past  for  the  production  of  extremely 
high  vacua  in  bulbs  and  it  has  been  found 
that  it  can  be  used  with  great  ease  for  this 
purpose.     The    following   directions  will 


prove  of  value  to  the  amateur  scientist  who 
desires  to  delve  into  the  great  mysteries 
offered  by  the  investigation  of  vacuum  tube 
phenomena. 

The  vessel  to  be  exhausted  is  filled  with 
a  gas  which  may  be  more  easily  condensed 
than  air;  as  carbonic  acid  gas.  The  vessel 
is  provided  with  an  extension  tip  which  can 
be  sealed  off  very  readily.  The  open  end  of 
the  extension  is  then  immersed  in  liquid 
air,  when  the  carbonic  acid  is  withdrawn 
from  the  vessel  and  deposited  in  the  ex- 
tension ;  this  is  then  sealed  off,  leaving  a 
high  vacuum  in  the  vessel. 

Precaution  should  be  exercised  when 
pouring  the  liquid  air,  as  a  drop  of  this 
liquid  when  in  contact  with  the  human  skin 
will  produce  a  severe  burn  which  is  diffi- 
cult to  heal.  It  is  advisable  to  siphon  the 
liquid  from  the  container  into  the  vessel 
which  is  to  be  exhausted.  Carbonic  acid 
gas  is  inflammable  and  care  should  be  taken 
to  keep  any  lighted  matches  away  from 
the  container  when  such  experiments  are 
conducted. 

Contributed  by      SAMUEL  COHEN. 


HOME-MADE  ELECTRIC  LOCK. 

A  cheap  and  efficient  electric  lock  can 
be  made  easily  if  the  following  plans  are 
followed.  The  drawing  speaks  for  itself, 
but  a  few  words  may  be  necessary.  The 
lock  box  F,  is  made  from  a  piece  of  sheet 
iron,  6"  long  by  AY2"  wide,  cut  as  shown 
in  the  figure.  It  is  then  bent  to  form  a 
box.  A  square  hole  is  cut  in  the  center 
of  one  end  and  2  Y&"  holes,  y2"  from  each 


Lock  box 


locA  tongue  Armature 


An  Electric  Lock  Presents  Many  Advantages 
Over  the  Ordinary    Mechanical   Type.  The 
Control  Button  May  Be  Placed  in  a  Secret 
Location. 

side.  The  two  electro-magnets  are  made 
as  follows: — two  pieces  of  iron  rod  Y&" 
in  diameter  and  3"  long  are  tapt  on  one 
end  for  No.  8-32  machine  screws.  A  fiber 
washer  in  diameter  is  put  on  each  end 
and  the  bobbin  wound  full  with  No.  18 
cotton  covered  magnet  wire.  A  piece  of 
brass  1"  long,  Yx"  wide  and  Yi"  thick  is 
filed  to  the  shape  shown  in  Fig.  B,  and  in 
one  end  a  Yx"  hole  is  tapt  in  the  center, 
and  2  holes  on  either  side  are  tapt  for 
No.  8-32  screws.  The  armature  as  shown 
in  Fig.  C,  is  made  from  a  piece  of  iron 
%"  thick  and  2"  long  by  Y%"  wide.  Three 
holes  are  drilled  in  it  to  correspond  with 
the  piece  of  brass  in  Fig.  B.  A  piece  of 
brass  rod  Ya"  in  diameter  and  Al/2"  long  is 
threaded  for  Yx"  on  one  end.  A  length 
of  brass  soring  wire  is  then  wound  around 
the  rod.  The  lock  is  now  ready  to  be  as- 
sembled. First  put  the  magnets  in  place 
with  8-32"  screws,  and  connect  the  two  in- 


side wires  together  and  the  two  outside 
wires  to  the  two  binding  posts  on  the  sides. 
Then  assemble  the  other  parts  as  shown  in 
Fig.  G.  Connect  it  in  series  with  a  push 
button  and  batteries,  and  when  the  circuit 
is  closed  the  electro-magnets  will  attract 
the  iron  armature  C,  thereby  releasing  the 
lock. 

Contributed  by   L.  E.  SUMMERTON. 


READING  VOLTS  AND  AMPERES 
WITH  THE  SAME  METER. 

A  volt  and  an  ammeter  are  usually 
mounted  on  the  experimenter's  switch- 
board. Too  often  those  meters  have  made 
a  considerable  dent  in  the  amateur  elec- 
trician's pocketbook  and  absorbed  money 
that  would  be  used  for  purchasing  other 
necessities.  What  then  is  required  is  a 
method  for  reading  both  volts  and  amperes 
on  the  same  scale  without  changing  the 
meter  itself  in  any  way. 

A  common  voltmeter  will  read  amperes 
on  the  same  scale  if  shunted  by  a  re- 
sistance of  one  ohm.  It  is  only  necessary  to 
wire  the  instrument  to  the  circuit  as 
shown  in  the  illustration,  Fig.  1.  Throw- 
ing the  switch  up  gives  ampere  readings 
and  down  gives  the  voltage. 

That  this  is  true  can  be  proved  by  Ohm's 
law.  Given  a  resistance  of  one  ohm  it  is 
clear  that  a  current  of  one  ampere  will 
flow  under  a  pressure  of  one  volt.  There- 
fore when  the  voltmeter  indicates  a  drop 
of  one  volt  across  the  one  ohm  resistance 
it  is  plain  that  one  ampere  is  flowing  thru 
the  resistance.  Should  the  meter  show  a 
drop  of  ten  volts  across  the  coil,  then  ac- 
cording to  Ohm's  law,  ten  amperes  will  be 
flowing.  The  voltage  drop  then  shows  di- 
rectly the  amperes  in  the  circuit. 

By  changing  the  resistance  of  the  coil 
it  is  possible  to  vary  the  range  of  the  in- 
strument. For  instance  should  a  coil  of 
one/half  ohm  be  shunted  across  the  meter 
the  reading  will  be  one/half  the  actual  cur- 
rent flow,  thus  when  the  meter  reads  10  the 
actual  amperes  are  20.  In  other  words 
E 

C  =  — . 
R 

Conversely  it  is  possible  to  read  the  volt- 
age with  an  ammeter  by  connecting  as  in 
Fig.  2.  In  this  case  the  resistance  is  con- 
nected in  series  with  the  meter.  The  prin- 
ciple being  again  based  on  Ohm's  law  which 
states  that  the  voltage  is  equal  to  the 
resistance  multiplied  by  the  current;  or 
E  =  RXC. 

Say  for  instance  that  the  coil  has  a  re- 
sistance of  10  ohms  and  the  meter  reads  5 
amperes.  By  multipling  these  together  we 
get  50  showing  that  the  voltage  applied  is 
50  volts. 

It  should  be  remembered  that  the  re- 
sistance used  should  be  heavy  enough  to 
carry  the  current  without  undue  heating. 
Furthermore  it  is  advisable  to  use  a  re- 
sistance wire  that  has  practically  no  tem- 
perature coefficient  such  as  "Thurlo"  wire, 
thus  doing  away  with  the  errors  that  would 
be  present  due  to  changes  of  resistance 
when  the  wire  is  heated  by  the  current. 

Contributed  by  THOS.  W.  BENSON. 


It  Isn't  the  Instruments  You  Have;  It's  the 
Way  You  Use  Them.  By  the  Application  of 
Ohm's  Law,  It  Is  Possible  to  Read  Volts  with 
an  Ammeter  or  Amperes  with  a  Voltmeter. 


472 


THE  ELECTRICAL  EXPERIMENTER 


November,  1917 


A  D.  C.  Step-Down  Rheostat,  Toaster  and  Stove 

By  W.  R.  WAY 


First  we  have  to  cut  a  piece  of  copper 
or  tin  to  the  rectangular  shape,  size  10" 
x  7y2".  One  inch  was  then  marked  off 
from  the  edges  all  the  way  around,  the 


Besides  being  an  excellent  toaster,  the 
device  makes  a  good  electric  stove  or 
heater,  or  it  may  be  used  as  either  a 
rheostat,  potentiometer,  or  resistance  for 


I  stove  bolls 


End  view  Side  v/ew 

Material  Req_d.   LA  piece  of  sheet  copper  or  /ran  a'*  a" 


Z8-0" 


Nichrome  wire.    3..  sporce/a/n  tries  6*/£*£    4-    ? wiring  cleats-  I  jTZ  , 
5  Asbestos  sheet  6*6".    6..  4-£  store- bolfsA  iong  &  2  boifs  f  tang  7.  Sma/t  scraps 


of  mica  &  sheet  copper  8  .  j  pieces  f a  ieiegraph  wire  about  7"  long . 


© 


The  Combination  Electric  Toaster  and  Stove  Here  Illustrated  and  Described  Will  Prove 
Very  Useful,  Now  That  Cool  Weather  Is  with  Us  Again. 


corners  cut  and  then  the  edges  bent  down 
to  an  angle  of  45  degrees  approximately, 
to  form  a  bevel  edge.  The  corners  were 
fastened  by  means  of  small  tacks  or  rivets 
clinched  on  one  side.  Cuts  were  taken  out 
of  the  bevel  edges  to  improve  the  appear- 
ance and  decrease  the  weight  of  the  base. 
Having  done  this  six  Yx"  holes  were  drilled 
in  the  top  of  the  base  at  their  correct 
distances  apart  as  shown  in  the  sketch. 
All  sharp  edges  were  either  bent  over  or 
filed  smooth.  The  base  may  now  be  con- 
sidered as  finished. 

A  sheet  of  6  x  6"  asbestos  board  1/16" 
thick  was  then  laid  on  the  base,  and  the 
cleats  placed  over  this  and  in  line  with 
their  respective  holes  in  the  base  top.  A 
Yz"  wide  strip  of  copper,  12"  long,  was  laid 
on  top  of  each  tile  (slate  or  asbestos 
board  will  serve)  and  holes  drilled  to 
suit  holes  in  cleat.  The  porcelain  tiles 
were  placed  in  position,  the  strip  of  copper 
placed  over  them  on  each  cord,  and  2Y&" 
stove  bolts  \Y\"  long,  were  used  to  bring 
the  two  strips  together  and  bind  the  cleats 
and  tiles  to  the  base  securely. 

The  heating  element  consists  of  28  feet 
of  No.  24  Nichrome  wire.  This  was  wound 
on  a  Y&"  steel  rod  in  spirals  of  6"  length 
and  a  single  wire  6"  long  left  between 
each  spiral.  Approximately  seven  spirals 
could  be  made  out  of  this  length  of  wire. 
When  the  wire  has  been  formed,  it  is 
wound  around  the  tiles,  the  coils  being 
placed  on  top  and  the  single  wires  under- 
neath the  tiles  so  as  not  to  lose  heat  down- 
wards and  heat  the  base  unduly.  The 
ends  of  the  wire  were  connected  to  two 
terminals,  having  mica  washers,  and  thence 
thru  a  cord  and  plug  to  the  110-volt  light- 
ing circuit.  The  toaster  was  then  com- 
plete. 


controlling  the  current  input  and  speed  of 
small  electric  motors  and  toys.  The  toast- 
er draws  about  2.25  amps.,  on  the  D.C. 
lighting  circuit,  and  I  successfully  oper- 
ated a  1/16  H.P.  27-volt  D.C.  series  mo- 
tor in  series  with  the  toaster.  It  is  made 
of  materials  (except  perhaps  the  wire) 
which  nearly  any 
experimenter  could 
easily  find  lying 
around  the  house, 
and  is  very  easily 
constructed. 


all  by  himself  with  his  wife,  who  is  also 
deaf,  could  answer  his  door  bell? 

Probably  there  have  been  many  schemes 
devised  so  that  a  deaf  man  might  know 
when  his  door  bell  rung.  Many  of  these 
unfortunates  depend  on  their  faithful  dogs. 

The  author  has  a  very  fine  dog,  who  can 
be  relied  upon  all  the  time,  but  Nature 
did  not  intend  that  he  should  remain  in- 
doors all  the  time.  Whenever  the  dog  is 
outdoors  for  his  daily  exercise,  the  door 
bell  proposition  presents  a  difficult  problem. 

The  deaf  man,  having  a  keen  bent  for 
electrical  novelties,  designed  an  electrical 
system  by  which  the  push  button  would 
turn  on  a  40-watt  Mazda  lamp  in  the  house 
which  would  light  up  a  room ;  this  light- 
ing up  of  the  lamp  is  quickly  noticed  by 
the  deaf  couple's  sensitive  eyes,  the  lighted 
lamp  being  a  signal  indicating  that  some 
one  is  at  the  door.  This  lamp  will  burn 
continuously  till  the  call  is  answered. 

The  details  and  wiring  diagram  of  the 
device  are  given  herewith.  The  details  of 
the  signal  system  are  as  follows :  When 
the  push  button  is  closed,  the  battery  cir- 
cuit is  closed,  energizing  a  pair  of  electro- 
magnets which  attract  a  special  form  of 
armature.  This  armature  has  a  trigger  on 
its  end,  and  on  its  travel  toward  the  poles 
of  the  magnets  releases  a  spring  lever.  This 
lever  falls  toward  a  stop  which  serves  as 
a  contact,  closing  a  secondary  circuit  which 
operates  a  40-watt,  110-volt  Mazda  lamp. 
The  spring  lever  remains  closed ;  then 
when  the  battery  circuit  is  opened  again, 
the  armature  trigger  moves  away  from  the 
magnets.  By  pulling  down  gently  the  reset 
chain  cord  secured  to  the  extreme  end  of 
the  pivoted  contact  lever,  it  is  brought  up- 
ward, passing  the  latch  of  the  trigger  and 
now  rests  on  the  top  part  of  the  trigger. 
In  resetting  this  way,  the  lamp  is  turned 
off  automatically,  and  the  next  time  the 
push  button  is  worked  the  whole  operation 
goes  on  all  over  again.  This  device  has 
been  in  use  since  last  February,  and  is 
serving  its  purpose  very  admirably. 

The  regular  door  bell  is  disconnected,  as 
there  is  no  need  for  it  in  this  house.  The 
dog  is  able  to  give  his  customary  warning 
by  the  slightest  noise  of  the  magnetic  pull 
and  click  of  the  contact  lever. 

This  man  is  working  on  an  electrical 
device  at  present  to  wake  him  up  in  the 


INDIA  INK. 
REMOVER. 

I  think  a  notice 
in  your  magazine 
to  the  effect  that 
India  ink  can  be 
completely  cleaned 
from  tracing  cloth, 
would  be  of  inter- 
est to  your  read- 
ers. It  is  claimed 
that  it  leaves  no 
trace  of  the  ink 
and  does  not  in- 
jure the  cloth.  This 
article  is  sold  and 
manufactured  un- 
der the  trade  name 
"RASINDIA"  and 
is  guaranteed. 
Cont.  by  W.  L. 
FETHERSTON. 


Push  bo  Hon 


HO/ 

Lpsocfcl 


Slate  base 


Std  parce/a/o  hnob 
•"•<^To  aftoch.p/vg  @ 


A  Deaf  Man  Invented  This  "Flash-Lamp"  Door  Alarm.    Pushing  the 
Button  Causes  the  Bell  Magnets  to  Trip  the  110  Volt  Lamp  Switch. 
It  Is  Reset  by  Hand  After  Each  Alarm. 


HOW  A  DEAF  MUTE  ANSWERS 
HIS  DOOR  BELL. 

Did  it  ever  occur  to  you  how  a  person 
who  is  totally  deaf,  and  living  in  a  house 


mornings,  since  alarm  clock  gongs  are  use- 
less to  him. 

Contributed  by  the  deaf  man  himself — 
K.  B.  AYERS. 


November,  1917 


THE  ELECTRICAL  EXPERIMENTER 


473 


Chemical  Action  of  Storage  Batteries 

By  ALBERT  W.  WILSDON 

(Concluded) 


IF  the  current  is  kept  constant  and  the 
value  of  V  is  measured  at  short  inter- 
vals, the  charge  and  discharge  curves 
obtained  are  of  the  form  shown  in 
Fig.  3.  The  value  of  V  rises  rapidly 
in  the  first  few  minutes  of  the  charge 
from  2.0  to  2.1  volts,  and  during  the 
rest  of  the  charge  continues  to  rise  slowly, 
until  at  the  end  it  suddenly  rises  to  2.5 
to  2.7  volts.  During  this  period  of  rapid 
rise  in  the  value  of  V,  the  cells  be- 
gin to  evolve  gas,  after  which  the  value  of 
V  changes  only  slightly.  On  allowing  the 
battery  to  stand  on  open  circuit  for  several 
hours,  the  electromotive-force  E  falls  to  the 
value  corresponding  to  the  density  of  the 


1.1 
It 

14 
11 

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If 

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Fig.   3. — Curves   Showing    Change   in  Lead 
Storage  Cell  Potential  on  Charge  and  Dis- 
charge. 


acid.  If  the  battery  is  then  allowed  to  dis- 
charge with  the  same  constant  value  of  the 
current  as  used  in  charging,  the  value  of  V1 
at  first  falls  rapidly  to  1.9  volts  and  then 
gradually  to  1.85  volts,  after  which  it  de- 
creases more  rapidly  to  zero.  The  curves 
given  in  Fig.  3  were  obtained  with  about  20 
per  cent  acid  and  a  current  density  of  about 
0.005  ampere  per  square  centimeter  of 
electrode  surface.  With  a  greater  current 
density  the  distance  between  the  charge  and 
discharge  curves  would  increase.  The  gen- 
eral character  of  the  curves  for  different 
makes  of  batteries  is  the  same,  tho  for 
those  having  a  thin  layer  of  active  material 
the  curves  are  more  marked,  and  for  those 
having  a  thick  layer,  they  are  more  rounded. 

From  the  fact  that  the  charging  potential 
V  is  several  tenths  of  a  volt  higher  than 
the  discharging  potential  V1,  as  is  shown  in 
Fig.  3,  it  is  evident  that  there  is  a  loss 
of  from  20  to  30  per  cent,  in  the  energy 
stored.  It  might  seem  at  first  sight  that  it 
results  from  the  loss  of  energy  due  to  the 
resistance  of  the  cell  itself,  to  the  IR  value 
in  equations  20  and  21,  but  the  value  of  the 
resistance  of  the  cell  is  too  small  to  ac- 
count for  such  a  large  loss.  On  open 
circuit  the  resistance  of  the  smallest  cells 
used  is  only  several  hundredths  of  an  ohm, 
and  no  large  increase  in  its  value  takes 
place  when  a  current  is  passing.  The  cause 
of  this  loss  in  energy  is  the  polarization  of 
the  electrodes  caused  by  the  change  in  con- 
centration of  the  acid  in  the  pores  of  the 
plates.  On  charging,  acid  is  formed  in  the 
pores  of  the  plates  where  it  becomes  more 
concentrated  than  in  the  rest  of  the  battery 
on  account  of  the  fact  that  diffusion  does 
not  take  place  with  sufficient  rapidity  to 
equalize  it.  Since  the  electromotive  force 
of  the  battery  increases  with  the  concen- 
tration of  the  acid  surrounding  the  plates, 
a  higher  imprest  electromotive  force  will 
therefore  be  necessary  in  charging.  On 
discharge,  the  acid  is  used  up  in  the  plates 
and  becomes  more  dilute  than  in  the  rest 
of  the  battery,  and  the  voltage  falls  cor- 
respondingly. The  charge  and  discharge 
curves  of  the  lead  battery  may  now  be 
taken  up  in  detail. 


The  Charging  Curve 
On  closing  the  charging  current,  sul- 
furic acid  is  immediately  set  free  at  both 
electrodes  and  the  electromotive-force 
therefore  rises  rapidly,  as  shown  by  the  por- 
tion of  the  curve  AB.  The  rate  of  diffusion 
increases  with  the  difference  in  concentra- 
tion of  the  acid  on  the  plates  and  in  the  rest 
of  the  battery,  and  when  concentration 
difference  has  become  so  great  that  the 
rate  of  diffusion  and  of  formation  are 
equal,  this  rapid  increase  ceases.  The  max- 
imum point  at  B  is  probably  due  to  the  de- 
struction of  the  thin  continuous  layer  of 
sulfate  which  forms  on  the  electrodes  dur- 
ing rest,  thus  reducing  the  resistance  of 
the  cell.  The  slow  regular  rise  to  C  is  due 
to  the  gradual  increase  in  the  density  of 
the  acid  and  also  to  the  deeper  penetration 
of  the  current  lines  into  the  active  mass 
and  the  corresponding  greater  difficulty  in 
equalizing  the  acid  concentration  by  dif- 
fusion. The  final  rise  CD  takes  place  when 
all  of  the  lead  sulfate  on  the  surface  of 
the  plates  has  been  used  up,  and  conse- 
quently the  sulfate  does  not  dissolve  rapidly 
enough  to  replace  that  electrolyzed  out. 
Very  soon  the  lead  solution  becomes  so 
dilute  that  the  work  necessary  to  deposit 
lead  is  equal  to  that  required  to  produce 
hydrogen  on  the  cathode  and  oxygen  on 
the  anode.  If  allowed  to  stand  on  open- 
circuit,  sulfate  diffuses  from  within  the 
plate  and  brings  back  the  electromotive- 
force  to  the  normal  amount.  The  max- 
imum point  at  D  is  due  to  the  mixing  of 
the  concentrated  acid  in  the  electrodes  with 
that  outside  by  the  gas  bubbles. 

The  Discharge  Curve 
In  discharge  the  acid  is  used  up  in  im- 
mediate proximity  to  the  electrodes,  and 
this  continues  until  the  concentration  dif- 
ference between  the  acid  on  immediate 
proximity  to  the  electrodes  and  in  the  rest 
of  the  battery  has  become  so  great  that 
diffusion  just  supplies  the  quantity  used  up. 
During  this  time  the  value  of  V1  falls 
rapidly  along  AE.  The  minimum  point  at 
E  is  possibly  caused  by  the  formation  of 
a  supersaturated  lead  sulfate  solution.  The 
solubility  of  lead  sulfate  in  a  20  per  cent 
solution  of  sulfuric  acid  decreases  with  de- 
creasing concentration,  so  that  at  the  be- 
ginning of  the  discharge,  when  little  solid 
sulfate  is  present,  a  supersaturation  of  short 
duration  is  probable,  and  the  electromotive- 
force  of  the  battery  decreases  with  increas- 
ing concentration  of  the  lead  ions.  The 
subsequent  gradual  fall  in  the  value  of  V1 
represented  by  EF  is  due  to  the  gradual 
decrease  in  the  density  of  the  acid  in  the 
entire  accumulator,  but  more  especially  to 
the  greater  difficulty  in  the  acid  diffusing 
deeper  into  the  plate  as  the  current  pene- 
trates deeper.  Finally  the  rate  at  which  the 
acid  diffuses  cannot  supply  the  acid  used  up 
by  the  action  of  the  current,  and  the  value 
of  V1  falls  off  rapidly. 

According  to  this  explanation,  the  loss  in 
energy  on  charge  and  discharge  is  due 
entirely  to  the  concentration  changes  that 
take  place  in  the  electrolyte  within  the  ac- 
tive mass.  The  smaller  these  concentration 
changes  are,  the  more  nearly  will  the  ac- 
cumulator approach  complete  reversibility. 
This  is  illustrated  in  Fig.  4.  These  curves 
were  obtained  with  an  accumulator  of  200 
ampere-hours  capacity.  It  is  seen  that  for 
a  current  of  0.1  ampere,  corresponding  to 
a  current  density  of  0.0017  ampere  per 
square  decimeter,  the  charging  and  dis- 
charging potential  differ  by  only  0.006  volt, 
or  0.3  per  cent  of  the  electromotive  force 
of  the  cell,  and  that  by  reducing  the  current 
this  loss  may  be  still  further  reduced. 


This  loss  is  not  distributed  equally  be- 
tween the  two  plates.  The  porosity  of  the 
lead  plate  made  from  the  same  sulfate  paste 
as  the  peroxid  is  about  1.4  times  as  great  as 
the  peroxid;  the  potential  of  the  peroxid 
plate  falls  off  about  1.6  times  more  than  the 
lead  plate  for  a  given  change  in  the  concen- 
tration of  the  acid,  and  finally  the  con- 
centration change  on  the  peroxid  plate  is 
greater  than  on  the  lead,  because  not  only 
is  sulfuric  acid  used  up  on  discharge,  but 
water  is  also  formed.  All  of  those  facts 
tend  to  make  the  loss  on  the  peroxid  plate 
greater  than  on  the  lead  plate.  When  the 
positive  and  negative  plates  are  made  of 
similar  frames  and  paste,  and  have  approx- 


i.oao 
ion 

1.074 

Che 

o                 oos                o.i  imp 

Fig.  4. — Change  in  Pole  Potential  of  Lead 
Storage  Battery  on  Charge  and  Discharge, 
as  a  Function  of  the  Current. 


imately  the  same  capacity  it  has  been  found 
that  60  to  70  per  cent  of  the  loss  takes  place 
on  the  peroxid  plate. 

The  capacity  of  an  accumulator  in  actual 
practise  means  the  number  of  ampere-hours 
that  can  be  taken  from  it  if  discharged  at 
about  nine-tenths  of  its  original  electro- 
motive-force, the  point  where  the  rapid  fall- 
ing off  in  the  electromotive-force  takes 
place.  The  capacity  therefore  is  determined 
by  the  rate  of  discharge,  for  the  smaller 
the  current  the  more  time  the  acid  has  to 
penetrate  by  diffusion  deeper  into  the  plate, 
when  all  of  the  active  material  on  the  sur- 
face has  been  used  up.  It  is  also  quite 
evident  that  the  conductivity  of  the  acid 
will  affect  the  capacity,  for  the  higher  the 
conductivity  the  deeper  will  the  current 
lines  be  able  to  penetrate  into  the  plate. 
Since  there  is  a  density  of  sulfuric  acid  at 
which  there  is  a  maximum  conductivity,  it 
would  be  expected  that  the  capacity  of  a 
lead  storage  battery  would  have  a  maximum 
value  for  this  density,  and  this  has  been 
shown  experimentally  to  be  the  case. 

The  current  efficiency  of  a  lead  storage 
battery,  or  the  ratio  of  the  number  of 
ampere-hours  obtainable  on  discharge  to  the 
number  put  into  the  battery  on  charge,  is 
from  94  to  96  per  cent.  The  small  loss  of 
4  to  6  per  cent  is  due  to  self-discharge  and 
to  the  small  amount  of  gassing  that  cannot 
be  avoided.  The  energy  efficiency,  on  the 
other  hand,  which  is  the  ratio  of  energy  ob- 
tainable in  the  external  circuit  on  the  dis- 
charge to  the  energy  put  into  the  battery 
on  charge,  is  only  from  75  to  85  per  cent. 
The  cause  of  this  comparatively  low  value, 
as  explained  above,  is  the  difference  be- 
tween the  charge  and  discharge  potential. 
The  loss  in  voltage  due  to  the  internal  re- 
sistance is  only  about  3  per  cent  with  the 
usual  acid  concentration  and  current  dens- 
ity. The  loss  due  to  polarization  is  a 
minimum  when  the  conductivity  of  the 
acid  in  the  battery  is  a  maximum,  for  in 
that  case  the  lines  of  current  spread  over 
a  larger  surface  by  penetrating  deeper  into 
the  plate. 

(Continued  on  page  493) 


4  74 


THE  ELECTRICAL  EXPERIMENTER 


November,  1917 


This  department  will  award  the  following  monthly  prizes:    First  Prize,  $3.00;  Second  Prize,  $2.00;  Third  Prize,  $1.00. 

The  purpose  of  this  department  is  to  stimulate  experimenters  towards  accomplishing  new  things  with  old  apparatus  or  old  material, 
and  for  the  most  useful,  practical  and  original  idea  submitted  to  the  Editors  of  this  department,  a  monthly  series  of  prizes  will  be  awarded. 
For  the  best  idea  submitted  a  prize  of  $3.00  is  awarded;  for  the  second  best  idea  a  $2.00  prize,  and  for  the  third  best  prize  of  $1.00.  The  article 
need  not  be  very  elaborate,  and  rough  sketches  are  sufficient.  We  will  make  the  mechanical  drawings.  Use  only  one  side  of  sheet.  Make 
sketches  on  separate  sheets. 


FIRST  PRIZE,  $3.00 


SECOND  PRIZE,  $2.00 


THIRD  PRIZE,  $1.00 


A  SMALL  INDESTRUCTIBLE 
RHEOSTAT. 

The  general  construction  of  the  majority 
of  small  rheostats  does  not  permit  of  ex- 
tremely rough  usage,  and  in  some  cases  is 
not  adapted  to  the  requirements  imposed 
upon  this  class  of  instrument.  In  a  word, 
those  with  wooden  bases  are  apt  to  be  de- 
stroyed by  fire,  and  the  ones  mounted  on 
porcelain  are  easily  broken. 

An  instrument  constructed  after  the  prin- 
ciple of  the  one  illustrated  herewith  will 
be  found  nearly  indestructible.  A  large  iron 
pulley  of  the  type  shown,  or  a  similar  form, 
provides  a  circular  groove,  at  the  perifery 
of  the  wheel  which  is  well  suited  to  hold 
the  slightly  stretched  spiral  spring.  This 
spring  is  of  fine  steel  wire  and  is  insulated 
from  the  wheel  by  a  narrow  strip  of  as- 
bestos. The  ends  of  the  wire  are  tied  to- 
gether with  asbestos  cord,  one  end  being 
grounded  to  the  wheel ;  to  permit  direct 
electrical  base  connection. 

Any  suitable  type  of  handle  can  be  fitted 
to  the  wheel  to  obtain  the  necessary  rotary 
adjustment.  Contacts  and  connections  can 
be  made  as  desired. 

Contributed  by        R.  U.  CLARK,  3rd. 


An  Unusual  But  Simple  Form  of  Battery 
Rheostat.    It  Comprises  a  Resistance  Coil 
Supported  on  a  Rotatable  Grooved  Pulley, 
Against  Which  a  Spring  Brush  Bears. 


ANENT  THE  "CAPILLARY" 
GRAVITY  CELL. 

I  read  with  great  interest  Mr.  Reed's 
article  on  "Bats"  in  the  August  Electrical 
Experimenter.  As  a  result,  I  made  one  of 
his  "capillary"  cells.  For  the  capillary 
cloth  I  used  a  piece  of  old  Turkish  towel. 
It  worked  excellently.  But  as  Mr.  Reed 
says,  the  internal  resistance  of  the  cell  is 
very  high. 

I  tested  the  current  of  my  cell  by  the 
loudness  of  the  sound  it  produced  in  a  tele- 
phone receiver.  I  had  four  dry  cells  which 
I  have  used  for  a  long  time.  The  capillary- 
cell  made  a  sound  not  quite  as  loud  as  one 
of  these  cells.  But  then  I  took  some  com- 
mon salt,  and  put  some  in  the  solution  in 
the  inside  cup,  in  the  water  outside,  and  on 
the  capillary  cloth.  I  used  enough  to  satu- 
rate the  solution.  Then  I  tested  my  cell, 
and  found  that  it  would  produce  a  sound 
in  the  telephone  receiver  as  loud  as  the 
four  dry  cells  together  connected  in  series. 

Contributed  by  WM.  A.  TRIPP. 


ELECTRIFYING  THE  CANDLE- 
STICK. 

Herewith  is  a  drawing  of  a  circular  wood 
base  to  which  a  standard  lamp  socket  is 


Board 


/r^_____^i_ 


Bolt  holding  cork\ 
to  boord 


Receptacle 


Cork  the  size 
■  of  a  candle  to 
fit  in  candle  stick 


EE3 


Here's  a  Simple  Way  in  Which  to  Elec- 
trify   Those    Handsome    Brass    or  Glass 
Candle-sticks    Which    are    Seldom  Used 
With    Messy   Wax  Candles. 

screwed.  The  wood  base  has  a  cork 
screwed  on  to  it  which  fits  down  in  the 
place  intended  for  a  candle  in  the  candle- 
stick. This  little  device  enables  one  to 
make  a  neat  electric  candle-stick  lamp  out 
of  a  few  odds  and  ends. 

Contributed  by  JOHN  S.  STEWART. 


A  WINDOW  TICKER  FOR 
HALLOWE'EN. 

A  window  ticker  for  Hallowe'en  or 
Thanksgiving  can  be  made  with  a  wooden 
pole  about  thirty-six  inches  long  or  more 
and  an  inch  and  a  half  wide.  A  bell  with  the 
gong  removed,  is  screwed  on  one  end  and 
is  connected  with  a  flashlight  battery  on  the 
other  end,  with  a  switch  or  a  push-button 
to  make  and  break  the  circuit.    The  battery 


Instead  of  Taking  Chances  With  the  Old 
Spool  Window  Ticker  on  Hallowe'en,  Use 
This  Simple  Electric  One  on  a  Long  Pole. 

is  the  kind  that  fits  in  a  pistol  flashlight. 
To  use  it  hold  the  tapper  of  the  bell  near 
the  window  and  push  the  button.  This  kind 
of  ticker  is  much  better  than  the  one 
operated  by  a  spool  with  notches  in  it. 
Contributed  bv 

THEODORE  A.  SMITH. 


To  solder  iron  use  a  flux  of  muriatic 
acid  which  has  been  "cut"  with  zinc 
scrap.    Don't  use  this  on  electric  work. 


A  TOY  ELECTRIC  STOVE  FOR 
THE  KIDDIES. 

The  day  of  electrical  toys  that  actually 
work  has  arrived,  as  is  evidenced  by  the 
many  practical  devices  on  the  market  in- 
tended to  amuse  the  youngsters. 

To  fix  a  toy  stove  so  that  it  really  heats, 
is  not  a  great  problem  for  those  who 
have  access  to  lighting  current.  A  common 
16-C.P.  carbon  filament  lamp  mounted  in  a 
toy  stove  will  add  greatly  to  its  interest 
retaining  qualities. 

This  can  be  accomplished  very  easily. 
A  hole  is  cut  in  one  side  of  the  stove 
large  enough  to  pass  a  key  socket.  It  is 
soldered  in  place  so  the  key  can  be  turned. 
An  incandescent  lamp  with  a  red  bulb  is 
now  screwed  into  the  socket  and  the  stove 
reassembled.  It  is  advisable  to  make  sure 
the  socket  is  in  good  condition  and  not 
"grounded." 

The  heat  given  off  by  the  lamp  will 
not  be  very  great,  but  the  fact  that  it 
does  heat  and  the  red  glow  coming  from 
the  various  parts  will  bring  pleasure  to 
the  little  "Housekeeper." 

Contributed  by    THOS.  W.  BENSON. 


To  Please  the  Kids  Why  Not  Turn  Their 
Useless  Toy  Stove  Into  an  Electric  one? 
An  Electric  Lamp  Does  the  Trick. 


REMOVING  ACID  STAINS. 

If  first  aid  is  given  to  acid-stained  cloth, 
one  may  often  remove  the  stain  without 
taking  the  trouble  to  neutralize  the  acid ; 
the  removing  agent  is  merely  chloroform. 
If,  however,  the  cloth  has  been  plainly 
injured  or  destroyed  by  the  acid,  strong 
ammonia  should  first  be  used  to  neutralize. 

In  the  case  of  hydrochloric  or  sulfuric 
acid,  concentrated  ammonia  alone  will  be 
sufficient.  But  beware  of  cheap  dyes !  Am- 
monia will  turn  a  pair  of  black-striped, 
beach  trousers  into  black  trousers.  In  such 
a  case,  chloroform  will  also  remove  the 
running  dye. 

Contributed  by  J.  FIERSTEIN. 


Don't  forget  to  send  a  photograph  of 
your  "rinktum"  with  your  description. 
It  makes  the  article  more  valuable  in 
every  way. 


November,  1917 


THE  ELECTRICAL  EXPERIMENTER 


475 


A  NOVEL  "WATER  MICROPHONE." 

I  give  herewith  a  diagram  and  descrip- 
tion of  a  very  sensitive  microphone  which 
is  very  simple  in  construction,  the  entire 
apparatus  being  made  from  a  tin  pan  and 
an  old  dry  cell  carbon. 

A  lengthy  description  is  unnecessary  as 
its  construction  can  be  easily  understood 
by  referring  to  the  accompanying  diagram, 


A    Novel    Experimental    Microphone  Made 
With  a  Pan  of  Water  and  Two  Carbon  Rod 
Contacts,  One  of  Which  Floats  on  the  Water 
As  Seen. 

in  which  B  is  the  stationary  carbon  contact, 
held  in  position  by  wooden  supports  D,  and 
A  the  loose  carbon  contact  which  is  slight- 
ly dished  as  shown  and  supported  by  wood- 
en float  C.  The  position  of  the  contacts, 
which  is  determined  by  the  water  level,  can 
be  accurately  adjusted  with  a  fountain  pen 
dropper. 

I  have  found  this  instrument  to  give  ex- 
cellent results  using  two  dry  cells.  If 
placed  on  a  table  a  pin  may  be  dropt  near 
it  and  heard  very  distinctly  in  the  'phones. 

Contributed  by  C.  RALPH. 


USING  A  TELEGRAPH  LINE  FOR 
TELEPHONE  AND  WIRELESS. 

Very  good  results  have  been  obtained 
with  circuits  indicated  in  the  accompanying 
drawing. 

To  talk  by  telephone  close  3  pt.  switch  on 
proper  point;  ordinarily  this  prevents  bat- 
teries from  running  down  when  not  in  use. 
R  is  the  receiver,  T  the  microphone,  Sw.  the 
3-point  switch,  B  the  battery  cells,  G  the 
ground,  K  the  telegraph  key  and  B2  the 
buzzer,  preferably  of  the  hy-tone  type. 

This  hook-up  was  used  on  a  line  about 
half  a  mile  long  with  six  stations  connected 
in  and  it  gave  the  best  of  results.  The 
buzzer  is  tuned  to  give  a  loud  buzz  in  the 
station  'phones  which  can  be  heard  at  a 
good  distance  from  the  set.  To  telegraph 
over  several  miles  of  wire  in  this  way  the 
buzzer  currents  can  be  intensified  by  in- 
serting inductances  at  X — X ;  these  may  be 
ordinary  gas  lighting  coils  costing  about 
$1.50. 

Contributed  bv   CHARLES  PHILLIPS. 


A   Clever   Scheme    Permitting    Telephone,    Telegraph  or 
Radio   Messages  to   be  Transmitted   and    Received  Over 
a  Telegraph  or  Lighting  Circuit. 


HOW  TO  MARK  YOUR  NAME 
ON  TOOLS. 

There  are  many  tools  used  by  mechanics 
that  are  so  delicate  in  construction,  that 
it  would  ruin  them  if  they  were  marked 


with  the  names  or  initials  of  the  owner 
put  on  in  the  usual  way  by  means  of  a 
steel  stamp ;  as  many  are  sprung  or  thrown 
out  of  adjustment,  which  renders  them 
useless  for  accurate  work.  By  the  chem- 
ical method,  names  or  initials  may  be  placed 
upon  tools,  etc.,  without  any  risk  of  their 
being  damaged.  The  corrodent  employed 
does  not  injure  the  hands,  nor  does  it  wear 
off  the  metal ;  while  the  solution  is  cheap 
and  easily  applied.  The  formula  is  as 
follows : 

Distilled  water   4  ounces. 

Copper  Sulfate   1  ounce. 

Salt    1  " 

Zinc  Sulfate  l/i  " 

Alum  Sulfate  *4  " 

Mix  all  the  chemicals  in  the  water  and 
shake  vigorously  until  they  are  dissolved. 
The  mixture  is  then  ready  to  use.  Now 
take  the  articles  to  be  marked ;  clean  the 
rust  off  of  the  metal  with  fine  sand  paper 
or  emery  cloth  on  the  spot  where  the  let- 
tering is  to  be  placed.  Smear  the  spot 
with  good  soap ;  then  write  down  the  name 
with  a  scriber  or  other  sharp  instrument, 
and  cover  the  marking  with  the  fluid — or 
better   still ;    fill   up   the  tracing   with  it. 

Leave  the  object  alone  until  the  name 
has  turned  copper-colored.  Moisten  the 
soap  with  water  and  rub  it  off.  The  solu- 
tion need  only  be  left  on  the  writing  five 
minutes.  The  mixture  is  to  be  used  only 
on  iron  or  steel  goods.  To  those  who 
would  like  to  have  their  names  put  on 
tools  in  a  neater  manner  than  is  possible 
by  the  use  of  a  scriber ;  the  use  of  rubber 
type,  which  can  be  bought  in  a  10-cent 
store,   is  recommended. 

In  using  these,  proceed  as  follows :  Set 
the  type  in  the  holder  in  the  reverse  direc- 
tion to  what  it  will  appear  when  printed ; 
or  in  other  words,  reading  from  right  to 
left.  Purchase  a  small  can  of  asphaltum 
varnish  from  a  hardware  store.  Also  tack 
a  piece  of  cotton  cloth  to  a  level  piece 
of  wood.  Spread  a  small  amount  of  the 
varnish  by  means  of  a  flat  stick,  on  the 
cloth ;  press  the  type  on  the  varnish,  then 
press  it  lightly  on  the  metal  and  let  dry. 
Make  a  small  rectangular  piece  of  wood 
about  l/i  of  an  inch  thick,  the  length  and 
width  depending  upon  the  size  of  the  tool 
and  name;  the  object  being  to  have  as 
wide  margins  as  possible  around  the  name. 

Bevel  the  sides  of  the  rectangular  piece 
of  wood  with  a  knife  or  file — a  steep  angle 
making  it  withdraw  easily  from  the  soap. 
Put  a  tack  in  the  middle  of  the  piece  of 
wood  to  serve  as  a  handle.  Lay  the  rect- 
angular piece  of  wood  over  the  name,  mak- 
ing sure  that  the  margins  are  equally 
spaced ;  then  put  soap  or  putty  around  the 
sides  of  the  wood  so  that  none  of  the  solu- 
tion will  escape.  Withdraw  the.  wood,  and 
fill  the  place  with  the  corrodent.  After 
five  minutes,  pour  the  latter  off ;  clear  away 
the  soap  as  previously  de- 
scribed and  you  will  have  the 
name  in  black  letters  on  a  cop- 
per-colored background.  The 
type  should  be  cleaned  after 
using,  turpentine  removing  the 
varnish  easily.  In  inking  the 
type  with  asphaltum.  care  must 
be  taken  not  to  get  too  much 
on,- as  it  will  clog  the  letters. 
If  the  type  should  have  too 
much  ink  on  it,  the  surplus 
can  be  gotten  rid  of  by  press- 
ing it  on  a  piece  of  paper. 
It  would  be  better  for  the  be- 
ginner to  try  the  process  on  a 
piece  of  iron  or  steel  before 
putting  his  name  on  the  tool ; 
thus  he  will  become  familiar 
in  handling  the  type  and  do  a  good  job. 
These  directions  for  doing  the  work  sound 
formidable ;  but  it  will  be  found  in  practise, 
that  it  is  a  very  easy  matter  to  place  names 
on  tools. 

Contributed  by  W.  S.  STANDIFORD. 


EXPERIMENTAL  ELECTRICAL 
FURNACE. 

The  drawing  in  this  article  shows  a  small 
electric  furnace  which  I  have  constructed 
in  my  shop  recently.  It  has  given  excel- 
lent results  and  I  think  it  will  interest  nu- 
merous other  amateur  electricians. 


Bet  carbon 


Toaster  in  series 
with  i  io  volt  AC 


Old  electric  bell 
filled  with  pondered 
carbon 


Here  is  a   Handy  Small-Sized  Electric  Fur- 
nace Which  Will  Weld  Almost  Anything. 

The  furnace  is  very  simple  in  construc- 
tion ;  the  drawing  will  explain  everything. 

To  operate  it  one  has  but  to  lower  the 
carbon  into  the  pot  of  carbon  dust  and 
then  gradually  raise  it  again.  A  white 
flame  plays  back  and  forth  from  the  car- 
bon to  the  dust,  and  by  inserting  a  piece 
of  metal  in  the  cup  it  is  quickly  fused. 
The  carbon  dust  may  be  obtained  by  filing 
or  grinding  a  battery  carbon. 

This  can  also  be  used  as  an  arc  light. 

Contributed  by 

STANLEY  PENBERTHY. 


A  GOOD  INDIRECT  LIGHT  MADE 
IN  TEN  MINUTES. 

Experimenters  who  have  access  to  elec- 
tric light  in  their  homes,  may  enjoy  an 
indirect  light  by  means  of  an  ordinary  tin 
reflector  and  socket. 

Three  holes   should  _  be   drilled  at 

angles  of  120  degrees  apart,  around  the 
rim  of  the  reflector.  Three  one  foot 
lengths  of  twine  or  wire  should  be  cut; 
knot  them  at  one  end,  and  attach  the  other 
ends  to  the  holes.     Loop  the  cable  and 


To  ceiling  — - 

y_  ^String  or  wire 

:  m/  Re f fee  for 

Cczt?/e^\  ^ 
\  f 

f  ® 

Do  You  Want  an  Indirect  Lighting  Fixture? 
Here's  a  Simple  Way  to   Make  One  for  a 
Few  Cents. 

attach  the  free  end  of  the  cord  to  it,  so  it 
will  stay  upside-down.  The  inside  surface 
of  the  reflector  should  be  painted  white, 
using  white  enamel  if  possible. 

Contributed  by    CHARLES  MASON. 


476 


THE  ELECTRICAL  EXPERIMENTER 


November,  1917 


Wit«inkles 


mm 


mlalafs 


EDITED  BY  S.GERNSBACK 


Under  this  heading  we  publish  every  month 
useful  information  in  Mechanics,  Electricity 
and  Chemistry.  We  shall  be  pleased,  of 
course,  to  hare  our  readers  send  us  any 
recipes,  formulas,  wrinkles,  new  ideas,  etc., 
useful  to  the  experimenter,  which  will  be 
duly  paid  for,  upon  publication,  if  acceptable. 


MISCELLANEOUS  FORMULAS  FOR 
THE  AMATEUR  CRAFTSMAN. 

No.  1. — Black  stain  for  wood:  The  in- 
tense black  color  that  cabinetmakers  pro- 
duce is  obtained  by  moistening  the  wood 
with  dilute  sulfuric  acid  and  afterwards 
gently  heating.  The  following  mixturp 
answers  well.  Sulfuric  acid,  one  ounce , 
water,  8  ounces.  When  cold  add  sugar  in 
the  proportion  of  1  ounce  to  ten  fluid 
ounces. 

No.  2.— Violet  Ink :  Primula  Violet,  V/6 
ounce.  Distilled  boiled  water,  3  quarts. 
This  can  be  converted  into  copying  ink  by 
adding  4  ounces  glycerin. 

Primula  violet  is  known  as  Hoffmans 
violet.  The  finest  shade  is  No.  6.  Other 
shades  can  be  made  from  other  colors.  Add 
about  5%  alcohol  and  1  to  4%  glycerin  to 
keep. 

No.  3. — Bronzing  Copper :  Castor  oil,  20 
parts ;  Alcohol,  80  parts ;  Soft  soap,  40 
parts ;  water.  40  parts.  After  copper  has 
been  scoured,  cover  with  the  above  mixture 
until  the  desired  color  is  obtained.  Then 
dry  in  hot  sawdust  and  coat  with  dilute 
varnish. 

No.  4. — Blue  Ink  for  use  on  glass :  A 
blue  fluid  for  writing  on  glass  which  is  not 
attacked  by  water  is  made  as  follows : 
Bleached  Shellac,  10  parts ;  Venice  Turpen- 
tine, 5  parts;  Oil  of  turpentine,  15  parts; 
Powdered  Indigo,  5  parts.  Mix  the  shellac, 
oil  of  turpentine,  and  place  in  water  bath 
under  gentle  heat  until  solution  takes  place. 
Then  add  the  indigo. 

No.  5. — Sticky  Fly  Paper  :  Resin,  1  lb. ; 
Molasses,  3^  ounces.  Boil  until  thick 
enough. 

No.  6.— Stove  Polish :  Black  Lead,  5 
parts ;  Bone  Black.  5  parts ;  Iron  Sulfate, 
10  parts.  Mix  thoroly  and  make  into  a  paste 
with  water. 

No.  7. — Hektograph :  Gelatin,  1  part ; 
Glycerin,  4  parts ;  Water,  2  parts. 

No.  1. — Ink  for  same:  Methyl  Violet,  1 
part ;  Water,  7  parts ;  Alcohol,  1  part. 

No.  2. — Rosaline,  2  parts ;  Water,  10 
parts;  Alcohol,  1  part. 

No.  8. — Solder  for  aluminum  :  Consists 
of  zinc,  tin,  aluminum  phosphorus.  The 
first  two  containing  the  bulk  of  the  alloy. 
This  solder  can  be  used  either  with  the 
blow  pipe  or  the  iron.  If  the  former  is 
used  a  little  silver  can  be  added  to  it  with- 
out making  it  melt  and  giving  it  a 
better  color.  The  surfaces  to  be  soldered 
are  first  scraped  clean  then  tinned  with  the 
solder  itself,  no  flux  being  needed.  Silver, 
2%  ;  Aluminum  Phosphorus,  9%  ;  Tin,  34%  ; 
Zinc,  50%. 

No.  9.— Liquid  Glue:  Chloral  Hydrat, 
250  grams;  Gelatin,  400  grams;  Water,  1,000 
grams.    The  solution  is  ready  in  48  hours. 

Contributed  by  HOWARD  A.  CROWL. 


HOLDING  ON  TO  THE  SCREW. 

A  clever  little  device  has  recently  been 
put  on  the  market  which  should  save  the 
motorist's  or  electrician's  vocabulary  of 
swear  words  from  being  overworked.  The 
device  is  made  of  specially  tempered 
crucible  steel  and  may  be  slipt  on  any 
screw  driver.  Once  in  place  it  serves  to 
hold  a  screw  firmly  on  the  end  of  the  screw 
driver  till  it  is  well  started  into  its  re- 
quired position. 


One  of  the  Latest  Devices  for  Mechanics  Is 
an    Attachment   for    Holding    On    to  Small 
Screws  in  Inaccessible  Places. 

Such  a  device  should  prove  particularly 
helpful  in  fastening  parts  of  machinery 
which  are  hard  to  get  at  and  which  require 
the  use  of  small  sizes  of  screws. — Con- 
tributed by  ALLEN  P.  CHILD. 

HOW  TO  SET  OFF  FLASHLIGHT 
POWDER. 

Very  often  one  wishes  to  set  off  flashlight 
powder  when  taking  an  indoor  picture,  etc. 
A  simple  way  to  set  off  the  powder  is  shown 
in  the  diagram. 

A  is  a  small  base  of  slate  2  inches  by  3 
inches.  B  two  binding  posts  taken  from  an 
old  battery.  Screw  the  posts  on  the  base 
about  one  inch  apart.  Procure  some  fine 
steel  wool  from  a  paint  store.  Pull  out  a 
strand  and  stretch  it  between  the  binding 
posts.  A  few  dry  cells  and  a  push-button 
are  connected  as  in  the  diagram. 

When  a  flashlight  picture  is  to  be  taken 
pour  some  powder  on  the  wire  and  push 


Base? 


nasM/gfif/ 

por/der 


Dry  ce//s 


Steel  wool 


When   Current   From   the   Battery   Is  Past 
Thru  the  Single  Strand  of  Steel  Wool,  It  Be- 
comes Incandescent;  Igniting  the  Flashlight 
Powder. 

the  button.    The  wire  will  become  red  hot 
and  will  ignite  the  powder.    A  reflector  is 
put  behind  the  base  to  increase  the  light. 
Contributed  by  HYMAN  R.  WALLIN. 


THERMOMETER  SCALES. 

Of  the  three  scales  in  general  use,  the 
Centigrade  scale  [also  called  Celsius]  is 
the  most  rational  one  and  the  one  used  in 
all  scientific  research  and  international 
literature ;  it  is  also  used  exclusively  in  most 
of  the  European  countries.  The  zero  point 
is  the  melting  point  of  ice,  and  the  100° 
point  is  the  boiling  point  of  water.  The 
Fahrenheit  scale  is  used  in  the  United  States 
and  England ;  on  this  scale  the  melting  point 
of  ice  is  exactly  32°,  and  the  boiling  point 
of  water  is  212°.  The  Reaumur  scale  is 
in  limited  use  in  Germany;  it  has  the  same 
zero  point  as  the  Centigrade  scale,  but  the 
boiling  point  of  water  on  this  scale  is  ex- 
actly 80°. 

TABLE   SHOWING  THE   COMPARISON  OF 
THE  READINGS  OF  THERMOMETERS. 
C  =  Centigrade,   or   Celsius.    R  =  Reaumur. 

F  =  Fahrenheit. 
C  R  F  C  R  F 

—  30     —24.0     —22.0  23       18.4  73.4 

—  25      —20.0     —  13.0  24       19.2  75.2 

—  20  —  16.0  —  4.0  25  20.0  77.0 
— 15      —  12.0      +   5.0  26       20.8  78.8 

—  10     —  8.0  14.0  27       21.6  80.6 

—  5      —  4.0         23.0  28       22.4  82.4 

—  4     —  3  2         24.8  29       23.6  84.2 

—  3     —  2.4         26.6  30       24.0  86.0 

—  2     —   1.6         28.4  31       24.8  87.8 

—  1  —  0.8  30.2  32  25.6  89.6 
Freezing   point   of   water  33       26.4  91.4 

0  0.0  32.0  34       27.2  93.2 

1  0.8         33.8  35       28.0  95.0 

2  1.6         35.6  36       28.8  98.8 

3  2.4         37.4  37       29.6  98.6 

4  3.2         39.2  38       30.4  100.4 

5  4.0         41.0  39       31.2  102.2 

6  4.8         42.8  40       32.0  104.0 

7  5.6         44.6  41       32.8  105.8 

8  6.4  46.4  42       33.6  107.6 

9  7.2         48.2  43       34.4  109.4 

10  8.0  50.0  44       35.2  111.2 

11  8.8  51.8  45       36.0  113.0 

12  9.6  53.6  SO       40.0  122.0 

13  10.4         55.4  55       44.0  131.0 

14  11.2  57.2  60       48.0  140.0 

15  12.0  59.0  65       52.0  149.0 

16  12.8         60.8  70       56.0  158.0 

17  13.6         62.6  75       60.0  167.0 

18  14.4         64.4  80       64.0  176.0 

19  T5.2  66.2  85       68.0  185.0 

20  16.0  68.0  90       72.0  194.0 

21  16.8         69.8  95       76.0  203.0 

22  17.6  71.6  100       80.0  212.0 

Boiling  point  of  water. 

To  convert  Centigrade  into  Fahrenheit: 
Degrees  Centigrade  multiplied  by  9,  and 

divided  by  5,  then  add  32. 
Example  —  80°  C.  X  9     5  =  144  +  32  = 

176°  F. 

To  convert  Fahrenheit  into  Centigrade: 

Subtract  32  from  the  number  of  degrees 
Fahrenheit,  then  multiply  by  5,  and  divide 

by  9.  , 

Example  —  100°  F.  —  32  =  68  X  5 -f- 9  = 
37.8°  C. 

To  convert  Reaumur  into  Fahrenheit: 
Degrees  Reaumur  multiplied  by  9,  divide 

by  4,  and  add  32. 

Example  —  16°  R.  X  9     4=  36  +  32  = 

68°  F. 

To  convert  Fahrenheit  into  Reaumur : 
32  subtracted  from  degrees  Fahrenheit, 

multiply  by  4,  and  then  divide  by  9. 
Example  —  95°  F.  —  32  =  63 9  X  4  = 

28°  R. 

The  above  table  and  formula  for  convert- 
ing the  different  degrees  to  another  will  be 
found  very  useful,  especially  when,  for  in- 
stance, you  have  facilities  to  work  with  a 
Centigrade  themometer,  and  the  Fahrenheit 
degree  is  mentioned. 

Contributed  by 

ALBERT  W.  WILSDON. 


FILLING  THE  FOUNTAIN  PEN 
WITHOUT  DROPPER. 

Oftentimes  a  person  finds  an  occasion  to 
fill  a  fountain  pen,  but  thev  have  no  drop- 
per handy.  So  here  is  a  little  trick  to  try 
on  your  fountain  pen.  Take  a  pin  or 
match,  and  draw  a  channel  out  to  the  edge 
of  the  mouth  of  the  ink  bottle,  with  the 
ink.  The  ink  will  follow  this  channel,  and 
run  into  the  fountain  -p?n,  without  spilling 
a  drop. 

Contributed  by   HOB  SON  ARNOLD. 


November,    i  9  1  7 


THE  ELECTRICAL  EXPERIMENTER 


477 


Experimental  Chemistry 


By  ALBERT  W.  WILSDON 

Eighteenth  Lesson 


Sodium  Hydroxid  (NaOH)  and  Potassium 
Hydroxid  (K.OH) 

HISTORY. 

THE  word  "Alkali"  meant  originally 
"Ash,"  a  particular  sort  containing 
Sodium  Carbonat,  and  used  in  glass- 
making.  Two  classes  of  alkalies 
were  early  distinguished — the  mild 
alkalies,  which  are  now  called  alkalin  car- 


Fig.  89.    Interesting  Experiment  with  Sodium 
and  Water.    The  Lighted  Splint  or  Combus- 
tion Test  Is  Tried  After  the  Sodium  Has 
Been   Dropt  in  the  Water. 

bonats,  as  Sodium  Carbonat,  and  the  caustic 
alkalis,  as  NaOH  (sodium  Hydroxid).  Two 
divisions  of  these  latter  are  now  made,  i.  e., 
the  volatile  alkali,  ammonium  hydroxid 
(NH4OH),  which  upon  the  addition  of  heat 
entirely  vaporizes,  and  the  fixt  alkalis,  which 
leave  a  solid  residue  on  the  evaporation  of 
their  solutions.  Sodium  and  potassium 
hydroxid  are  two  examples  of  these.  With 
strong  heat  these  vaporize  but  do  not  break 
up,  and,  until  Davy's  experiments  on  them 
with  the  aid  of  the  electric  current,  they 
were  regarded  as  elements. 

In  1736  Duhamel  distinguished  Sodium 
hydroxid  from  potassium  hydroxid,  previ- 
ous to  which  there  was  no  distinction  be- 
tween them,  or  the  salts  of  sodium  and 
potassium.  The  latter  then  became  known 
as  "  potashes." 


Fig.  88.    Diagrammatic  View  of  the  Castner- 
Kellner  Process  for  the  Electrolytic  Produc- 
tion of  Caustic  Soda  and  Caustic  Potash. 


In  1807  Davy  discovered  the  metal  potas- 
sium, by  the  electrolysis  of  potassium 
hydroxid.    Thus  by  the  decomposition  of 


potassium  hydroxid  by  electrolysis  it  was 
proved  that  they  were  not  elements. 

OCCURRENCE:— Owing  to  their  strong 
affinities,  neither  potassium  nor  sodium 
hydroxid  are  found  in  the  free  state.  Sodium 
or  Potassium  occur  very  commonly  as 
silicates  in  granite  and  other  rocks,  and  in 
their  chlorids  (Sodium  Chlorid,  NaCl,  and 
potassium  chlorid,  KC1)  and  in  other  salts, 
but  never  free.  Potash  (K2CO3)  is  the 
principal  alkali  of  the  animal  body,  hence 
the  need  of  potassium  in  food  plants. 

PREPARATION  :— 1.  It  is  conveniently 
prepared  by  the  interaction  of  metallic 
sodium  or  potassium  with  water. 

Na  +  H-O  =  NaOH 
K    -)-  H20  =  KOH 

2.  THE  ELECTROLYTIC  PRODUC- 
TION OF  CAUSTIC  SODA  AND  CAUS- 
TIC POTASH  :— This  will  probably  be  of 
most  interest  to  readers  of  this  journal,  as 
one  of  the  methods  of  preparation. 

There  have  been  numerous  methods  and 
processes  invented  for  the  manufacture  of 
the  caustic  alkalis  by  electrolysis.  Probably 
the  best  known  method  is  the  Castner-Kell- 
ner  process.  This  consists  of  a  tank  (Fig. 
88)   which  is  divided  into  three  compart- 


Fig.  91.    Experiment  No.  101,  in  Which  Sodi- 
um   Hydroxid    Is    Produced    by    Heating  a 
Solution  of  Water,  Slaked  Lime  and  Sodium 
Carbonat. 


ments  as  shown;  the  two  outside  (BB) 
contain  the  sodium  or  potassium  brine,  and 
the  carbon  anodes  (++)■;  while  the  centre 
one  (E)  contains  the  iron  cathode  (D). 
Thru  this  inside  compartment  (E)  a  con- 
tinuous supply  of  water  flows,  which  takes 
up  the  caustic  soda  (or  potash)  produced 
and  is  conducted  off  into  collecting  tanks. 
The  partitions  (FF)  are  open  below,  just 
reaching  to  the  surface  of  a  layer  of  mer- 
cury (CC)  which  covers  the  entire  bottom 
of  the  tank.  The  metal  (Sodium  or  potas- 
sium) liberated  amalgamates  at  once  with 
the  mercury  (C),  which  by  the  tilting  of 
the  whole  apparatus  up  and  down,  by  means 
of  a  cam  passes  into  the  middle 
compartment  (E),  where  it  acts  as  the 
anode  during  the  passage  of  the  current  to 
the  iron  cathode  (D)  ;  the  metallic  sodium 


(Na)  or  Potassium  (K)  of  the  amalgam 
is  thereby  liberated,  which  reacts  with  the 
water  present,  forming  sodium  (or  potas- 
sium) hydroxid,  and  hydrogen  gas  which 
is  formed  at  the  negative  electrode  ( — ). 
From  the  compartments  (BB)  chlorin 
passes  as  a  gas  to  the  upper  parts,  which  is 
then  drawn  off  and  utilized  for  making 
bleaching  powder,  hydrochloric  acid,  etc. 
The  lye  obtained  from  the  cathode  chamber 
(E)  contains  about  20  per  cent  of  caustic 


Fig.  92.     Home-made  Laboratory  Apparatus 
for  the   Electrolytic    Preparation  of  Sodium 
Hydroxid.     It  is  Used  in  Conjunction  with  a 
Battery. 

soda  or  caustic  potash,  which,  after  evapora- 
tion, yields  a  product  of  about  99.5  per  cent 
pure. 

3.    On  the  commercial  scale  sodium  hy- 
droxid is  produced  by  a  modification  of  the 
LeBIanc  process  for  preparing  sodium  car- 
( Continued  on  page  494) 


Fig.  90.   Another  Sodium  and  Water  Experi- 
ment— After  the  Action  Stops  the  Air  Orifice 
of  a  Bunsen  Burner  Is  Held  Over  the  Bottle, 
Giving  a  Yellow  Color  to  the  Flame. 


478 


THE  ELECTRICAL  EXPERIMENTER 


November,  1917 


Our  Amateur  Laboratory  Contest  is  open  to  all  readers,  whether  subscribers  or  not.  The  photos  are  judged  for  best  arrangement  and  efficiency 
of  the  apparatus.  To  increase  the  interest  of  this  department  we  make  it  a  rule  not  to  publish  photos  of  apparatus  unaccompanied  by  that  of  the  owner.  Dark 
photos  preferred  to  light  toned  ones.    We  pay  each  month  $3.00  prize  for  the  best  photo.    Make  your  description  brief  and  use  only  one  side  of  the  sheet. 

Address  the  Editor,     With  the  Amateurs"  Dept. 


At  Last  Some  "Electrical  Laboratory"  Photos  !  !  ! 

At  last  the  "Radio-bugs"  seem  to  be  waking  up.  Observe  the  four  Electrical  laboratory  photos  we  have  with  us  this 
month.  Now,  why  is  it  that  we  can't  receive  more  photos  from  "ELECTRICAL  LABORATORY"  owners,  when  there  are 
about  a  million  of  you  scattered  thruout  the  United  States  at  this  very  moment!  As  you  will  remember  we  made  all  of  you 
a  special  offer  in  the  September  number,  viz.,  we  offered  to  give  not  only  the  $3.00  monthly  prize  for  the  best  "Electrical  Lab." 
photo,  but  5  (five!!!)  additional  prizes  of  one  year's  subscription  to  this  journal,  and  a  copy  of  the  "EXPERIMENTAL 
ELECTRICITY  COURSE"  for  the  best  five  photos  submitted,  after  awarding  the  first  prize.  And  all  the  answers  we 
receive  are  FOUR  photos.  After  awarding  first  prize  of  $3.00  the  remaining  three  have  been  awarded  a  year's  subscription 
and  a  copy  of  the  famous  Experimental  Electricity  Course.  As  we  have  just  said,  it  is  strictly  up  to  you  whether  you  wish 
to  take  a  chance  on  winning  the  $3.00  cash  prize,  and  also  if  you  wish  to  throw  away  the  chance  of  receiving  "The  ELEC- 
TRICAL EXPERIMENTER"  magazine  for  one  year  free  of  all  cost,  besides  the  copy  of  the  Experimental  Electricity 
Course,  which  is  worth  $1.00  alone  to  my  electrical  student.    Address  the  Editor  "With  The  Amateur's  Prize  Contest." 


A  GROUP  OF  REPRESENTATIVE  AMERICAN  AMATEUR  LABORATORIES 

Electrical  Laboratories  of,  1— Joseph  F.  Birchler,  St.  Louis,  Mo.  ($3.00  Prize);  2— Trios.  W.  Benson  and  Mr.  Uphoff,  Phila- 
delphia, Pa.;  3— Earl  Scottie  Ensign,  Toledo,  O.;  4 — James  L.  Clifford,  Evansville,  Ind.  (Nos.  2  to  4,  inclusive,  each  awarded 
one  year's  subscription  to  the  "E.  E."  and  a  copy  of  the  "Experimental  Electricity  Course);  Radio  Stations  of  5 — Osmond  Ryer, 
Pasadena,  Calif.;  6— Clarence  de  Witt   Rogers,  Jr.,   Larchmont   Manor,    N.   Y.:   7— W.    Leathe,    Larchmont,    N.    Y.;   8— Raymond 

Yoder,    Newton,    Kansas;   9 — James  Girand,  6EO,   Phoenix,  Ariz. 


November,  1917 


THE  ELECTRICAL  EXPERIMENTER 


479 


An  Exceptional  Experimental  Laboratory 

By  GEORGE  HOLMES  and  ALBERT  W.  WILSDON 


THE  Editors'  very  appealing  and 
pathetic  "S  0  S"  for  electrical  and 
kindred  laboratory  photographs,  was 
picked  up  on  our  short  wave  re- 
generative set,  and  due  to  the  strong 
regenerative  action,  we  take  great  pleasure 
in  introducing  our  laboratories  to  Elec- 
trical Experimenter  readers  together  with 
photos  and  data. 

In  obscurity  for  several  years,  our  en- 
deavors have  been  constantly  branching 
out,  ever  since  the  early  stages  of  the  radio 
babyhood.  Our  complete  laboratory,  scien- 
tific instruments,  periodicals,  and  various 
equipment  is 
the  outcome 
of  nigh  on  to 
ten  years  ac- 
c  u  mulation. 
By  this  we  do 
not  mean  that 
we  have  pre- 
served all  of 
the  apparatus 
which  was 
made  and  ac- 
quired during 
this  period, 
but  specimens 
of  the  early 
stages  of  elec- 
trical, chem- 
ical and  radio 
apparatus 
h  ave  been 
carefully  pre- 
served, and  the  remainder  of  the  be- 
loved "junk"  has  been  either  dis- 
mantled or  thrown  away  to  make 
room  for  modern  equipment,  which 
has  been  proven  more  efficient  than 
the  older  types. 

The  laboratories  cover  a  space  of 
four  rooms  which  are  divided  as  fol- 
lows:  The  first  floor  contains  our  of- 
fice, with  up-to-date  filing  systems, 
which  enables  us  to  instantly  refer 
to  any  special  topic,  or  any  certain 
piece  of  intricate  apparatus ;  which 
by  the  way,  is  only  one  of  our  novel 
features.  By  labeling  a  certain  piece 
of  apparatus  with  what  we  call  a 
"key,"  and  putting  the  data  on  a  fil- 
ing card,  then  by  reference  thereto, 
valuable  time  and  trouble  are  saved 
by  this  system.  Our  books,  consist- 
ing of  hundreds  of  scientific  books, 
periodicals,  magazines,  patent  papers,  scrap 
books  containing  clippings  of  interest,  and 
bearing  on  all  scientific  subjects,  were  taken 
from  papers  as  far  back  as  ten  years.  The 
library,  with  the  aid  of  our  filing  system, 
is  of  great  convenience  when  conducting 
experiments.  Many  pleasant  winter  even- 
ings have  been  spent  in  this  room,  chatting 
and  discussing  future  and  past  experi- 
ments and  research  problems. 

Above  the  office  is  the  "Radio"  room, 
Research  and  Testing  room,  Photographic 
dark  room,  and  Chemical  Laboratory. 

The  layout  of  our  Radio  room  may  be  of 
interest  to  readers  who  are  contemplating 
overhauling,  or  reconstructing  their  sets. 
On  the  right  hand  side  of  the  room  are  the 
switchboards,  constructed  of  slate,  all  the 
wiring  being  past  thru  approved  conduit. 
Fig.  (1),  shows  these  switch-boards  and 
a  group  of  relays.  Either  D.  C.  or  A.  C. 
current,  varying  from  one  to  two  hundred 
and  fifty  volts  are  instantly  available,  which 
of  course  is  of  great  advantage  in  many 
experiments.  A  certain  laxity  on  some 
of  the  work  prevails  owing  to  the  numer- 
ous cables  which  have  to  be  strung  tem- 
porarily, such  as  for  testing  arcs,  etc. 
Fig.    (3)    shows   a   partial   view   of  the 


Radio  Apparatus,  which  is  all  home-made. 

Our  radio  apparatus  is  of  course  now 
cut  off  from  actual  service,  in  accordance 
with  the  proclamation  of  the  President,  and 
a  careful  scrutiny  of  the  rotary  gap  and 
oscillation  transformer  under  the  table, 
discloses  the  wire  sealing  it  up,  upon  which 
we  have  placed  a  tag  bearing  the  inscrip- 
tion "Sealed  in  accordance  with  President 
Wilson's  Proclamation.  Here  lies  the 
remains  of  Pal  Wireless,  who  died  a 
struggling,  and  sudden  death.  May  his 
spirit  be  reincarnated  in  all  the  glory  of  the 
original."    Seems  a  funny  sort  of  thing  to 


Figs.  1  (Upper  Left),  2  (Upper  Right)  and  3  (Bottom 
View),  Illustrating  the  Excellent  Electrical  and  Chemi- 
cal Research  Laboratory  Owned  by  Two  Live-Wire  Ex- 


perimenters.   Such  a 


Laboratory 
Proud  of. 


Is  Something  to  Be 


be  tagging  on  a  wireless  set — don't  it?  But 
when  we  go  over  the  pleasant  memories  of 
the  incoming  signals  from  Nauen,  Sayville, 
and  other  high  powered  stations  we  feel 
a  lump  in  our  throat,  but  of  course  we  pass 
it  over  (not  the  lump,  but  the  ban),  say- 
ing "What  has  happened,  had  to  happen, 
and  it  must  be  for  the  best."  We  sincerely 
hope  that  it  is  for  the  best,  and  have  in 
fact,  mapt  out  "some  set,"  incorporating 
several  new  features,  such  as  Morecroft 
inductances.  We  trust  that  the  reader  will 
pardon  us  for  this  lengthy  post  mortem 
statement,  but  we  feel  certain  that  like 
thoughts  are  creeping  into  his  own  mind  on 
glancing  over  our  belated  loss. 

Well,  to  get  down  to  brass  tacks,  the 
general  layout  will  probably  be  of  interest. 
Facing  the  south  against  the  window 
shown  on  the  extreme  right  of  the  Radio 
"Lot"  photo,  are  the  operators'  desks,  upon 
which  a  large  square  glass  plate  is  placed 
and  under  which  a  map  of  the  important 
radio  stations  is  located,  which  we  have 
improved  upon  by  placing  the  call  letters 
after  them ;  thus  enabling  us  to  determine 
the  distance  of  the  station.  Under  the  glass 
is  also  placed  various  station  calls  and  mis- 
cellaneous information  of  importance  to  the 


operator.  Next  to  our  right  hand  are  the 
push  buttons  for  the  rotary  gap,  and  the 
radio  transmitting  key  together  with  keys 
for  the  outside  telegraph  lines,  thus  permit- 
ting us  to  get  in  communication  at  once 
with  the  various  stations  on  our  lines  via 
telegraph.  To  the  left  of  the  operators' 
position  may  be  seen  the  aerial  switch,  hot 
wire  radiation  meter,  one  step  Audion 
amplifier,  damped  and  un-damped  wave 
receptors,  crystal  detector,  receiving  set, 
also  a  large  loading  inductance.  The  receiv- 
ing circuits  are  all  connected  with  Litzen- 
draht  and  soldered.    Three  pairs  of  'phones 

are  available. 

On  the  ex- 
treme left  of 
the  photo  may 
be  seen  a  port- 
able sending 
and  receiving 
set.  The  port- 
able transmit- 
ting set  con- 
sists of  a  one 
inch  spark 
coil  with  the 
necessary  ac- 
cessories. The 
receiving  set 
contains  a 
loose  coupler 
of    our  own 
design,  vari- 
ables, loading 
i  n  ductance, 
and  the  necessary  switches.  With  this 
field  set  we  were  able  to  keep  in  con- 
stant touch  with  the  parent  station 
while  conducting  tests,  a  great  factor 
which  enables  us  to  make  accurate 
measurements,  and  keep  accurate  data 
on  hand  for  future  experiments. 

Underneath  the  table  is  the  regular 
transmitting  set,  (now  "sealed"  of 
course,  for  the  duration  of  the  war) 
consisting  of  a  1  K.  W.  Thordarson 
transformer  and  oil  condenser,  these 
two  being  placed  in  the  large  cabinet 
under  the  table.  On  the  top  of  the 
case  is  the  rotary  spark  gap,  and 
brass  ribbon  oscillation  transformer. 
All  the  leads  are  short  and  are  of 
flexible  copper  cable  with  heavy  rub- 
ber insulation.  The  ends  being 
soldered  into  lugs. 
The  aerial  used  consisted  of  a  large 
100  ft.  iron  pipe  mast,  having  short  and  long 
wave-length  aerials,  together  with  the 
necessary  ground  switches.  (The  aerial  is 
not  up  at  the  present  writing!)  The  aerials 
consisted  of  500  feet  of  phosphor  bronze 
wire  for  the  reception  of  long  and  un- 
damped waves,  and  the  second  of  a  4  wire 
80  feet  long,  adapted  to  transmitting  and 
receiving  on  a  short  wave  regenerative  set. 

On  the  other  side  of  this  room  are  placed 
two  drafting  tables,  upon  which  new  ap- 
paratus are  designed  and  drafted. 

The  room  directly  opposite  the  radio- 
room  is  the  laboratory,  around  the  walls  of 
which  are  placed  shelves  to  hold  the  various 
instruments  and  supplies.  A  large  table  in 
the  centre  of  the  room  holds  the  numerous 
testing  devices  ;  such  as  Wheatstone  bridges, 
wave-meters,  decremeters,  hot  wire  meter, 
volt  meters  and  ammeters. 

In  one  corner  of  the  room  are  located 
the  chemical  and  testing  tables,  which 
permits  tests  to  be  made  while  the  experi- 
ment is  in  progress,  and  in  this  way  we 
have  the  advantage  of  several  readings  with 
which  we  can  compute  the  results.  The 
chemical  laboratory  is  completely  equipt, 
containing  all  the  common  reagents  and 
(Continued  on  page  500) 


480 


THE  ELECTRICAL  EXPERIMENTER 


November,  1917 


rtEst  Patents 


Illuminated  Display  Apparatus. 

(No.  1,238,739;  issued  to  Frederick 
C.   Bowdidge  and   Preston  C.  Mc- 
Mullen.) 

This  patent  describes  a  very  simple 
and  yet  effective  device  for  creating 
the  effect  of  a  waving  flag  or  other 
moving  object.     A  glass  screen  in 


the  front  of  cabinet  shown,  has  for 
instance  a  waving  fiig  painted  on 
the  face  of  it.  Back  of  this  screen 
there  are  placed  several  lamps  for 
illumination  and  in  front  of  this  a 
slowly  revolving  metal  spiral  con- 
nected to  a  small  electric  motor. 
For  best  results  the  space  around 
the  flag  should  be  made  opaque.  The 
spiral  is  cut  out  from  a  flat  piece  of 
metal  and  afterward  expanded  to  the 
shape  shown  in  the  cabinet. 


Telephone  Helmet  for  Aviators 

(No.  1,235,851;  issued  to  Jesse  Lee 
Spence.) 

The  patentee  here  provides  an  im- 
proved form  of  telephone  helmet  for 
aviators,  the  helmet  proper  being 
composed  of  leather  or  other  suitable 
material.      Instead    of    the  helmet 


being  fitted  with  two  telephone  re- 
ceivers pressing  against  the  ears,  use 
is  made  of  a  single  telephone  re- 
ceiver mounted  at  the  top  of  the 
helmet.  This  communicates  with 
two  sound  channels  which  extend 
downward  on  either  side  of  the 
helmet  to  the  ears.  The  microphone 
is  adjustably  supported  on  a  remov- 
able bracket,  pivoted  on  either  side 
of  the  helmet  in  the  manner  shown. 


Electrical  Gun 

(No.  1,239,344;  issued  to  Levi  M. 
Bowman   and    William    A.  Smith.) 

This  represents  an  electrically 
fired  gun  which  appears  to  possess 
several  meritorious  features.  Acci- 


dental  discharge  is  prevented,  for  one 
thing,  and  after  having  once  been 
sighted,  the  pulling  of  the  trigger  to 
fire  the  gun  will  not  pull  the  gun  off 
from  the  object  sighted  at.  Further, 


this  electrical  gun  structure  in- 
cludes a  special  primer  or  firing 
cap  which  carries  a  sparking  point, 
so  that  the  shell  is  discharged  by 
the  formation  of  a  disruptive  spark 
in  the  primer.  The  stock  of  the 
gun  contains  a  battery  which  is  con- 
nected to  a  spark  coil  in  the  usual 
manner.  The  spark  coil  primary  cir- 
cuit is  controlled  by  the  trigger  con- 
tact. 


Underwater  Radio  Scheme 

(No.  1,233,211:  issued  to  Frank  P. 
Fisher  and  Hugh  Dehart.) 
Under-water  telegraphy  can  be 
carried  on  by  this  arrangement  over 
considerable  distances  it  is  claimed. 
The  apparatus  involved  is  very  sim- 
ple, comprising  for  the  transmitting 
set  simply  a  small  induction  coil  con- 


nected  with  a  source  of  power  and  a 
signaling  key.  The  secondary  leads 
from  the  coil  are  connected  to  a 
double  pole,  double  throw  switch  as 
shown,  so  that  the  receiving  set 
(pair  of  'phones)  can  be  switched 
in  when  desired.  The  blades  of  the 
switch  are  connected  to  two  carbon 
electrodes  submerged  in  the  water, 
a  suitable  distance  apart.  It  has 
been  found  that  about  20  feet  apart 
is  the  proper  distance  to  set  the 
electrodes  for  an  apparatus  having 
a  range  of  500  to  1,000  feet.  It  is 
mentioned  that  communication  can 
be  established  with  submarines. 


Telephone  Amplifier 

(No.  1,232,514;  issued  to  Henry  C. 
Egerton.) 
This  invention  relates  to  amplifier 
svstems  for  increasing  the  intensity 
of  telephone  currents.  It  permits 
several  stations  similarly  equipt  and 
on  a  common  circuit  to  be  supplied 
with  current  from  one  and  the  same 


service.  The  loud-talking  receiver 
and  horn  are  actuated  thru  a  trans- 
mitter element  15,  which  is  in  turn 
controlled  by  the  amplifier  motor  12, 
which  is  of  special  construction.  It 
is  rendered  particularly  sensitive  to 
telephonic  currents  by  means  of  two 
distinct  windings,  conected  in  such 
relation  one  with  the  other,  that 
opposite  magnetic  polarities  are  pres- 
ent within  each  core;  therefore  a 
given  impulse  of  current  thru  the 
operating  windings  acts  to  increase 
the  magnetic  pull  at  one  end  of  the 
armature,  while  decreasing  the  mag- 
netic pull  at  the  other  end  of  the 
armature,  all  in  a  well-known  man- 
ner. Suitable  bearings  at  the  middle 
pole-piece  of  the  amplifier  electro- 
magnet, permit  the  armature  of  this 
COPIES  OF  ANY  OF  THE  ABOVE 


magnet  to  move  reciprocally  in  a 
rocking  manner  in  unison  with  re- 
versals or  changes  in  amplitude  of 
the  telephone  curent,  thereby  vary- 
ing the  pressure  on  the  active  ma- 
terial of  the  transmitter  element  15. 


Telephone    for    Transmitting  and 
Reproducing  Sounds 


(No.  1,238,439;  issued  to  Rudow 
Rummler.) 

This  invention  relates  to  tele- 
phones, wherein  a  diafram  and  a 
coil  of  wire  are  so  arranged  that  the 
coil  may  exert  a  direct  inductive 
action  on  the  diafram,  more  or  less 
independently  of  the  permanent  mag- 
net, and  provides  means  for  mag- 
netically suspending  the  diafram  in 
a  magnetic  circuit. 

In  the  construction  shown,  an 
electrical  diafram  1,  of  magnetic  ma- 
terial, such  as  soft  iron,  is  placed 
above  the  flat,  spiral  elliptical  coil  of 
insulated  wire  2,  this  coil  being  con- 
nected in  the  usual  manner.  The 
permanent  magnet  is  seen  at  3. 


Rectifying  Spark  Gap  for  Radio 

(No.  1,235,935;  issued  to  Archibald 
Shaw.) 

This  design  of  high  tension,  high 
frequency  spark  gap  is  one  of  the 


best  yet  brought  out.  It  employs 
a  fine  stream  of  gas,  such  as  air, 
under  high  pressure  which  is  forced 
out  thru  the  center  of  the  smaller  or 
point  electrode  of  the  gap.  This 
stream  of  air  is  forced  against  a 
relatively  large  flat  disc,  and  when 
the  primary  and  secondary  circuits 
to  which  such  a  gap  are  in  resonance, 
no  arcing  will  occur,  but  the  dis- 
charge will  take  the  form  of  a 
bluish-white  incandescent  blaze  of 
tapered  form,  extending  across  the 
gap;  furthermore  a  pulsatory  dis- 
charge having  a  very  hijjh  frequency 
passes  in  one  direction  only.  It  has 
been  found  best  to  employ  an  air 
pressure  of  110  lb.  per  sq.  in. 

Making  Cartoon  Movies 

No.  1,235,871;  issued  to  Carroll  M. 
Aument.) 


This  scheme  provides  for  the  tak- 
ing of  cartoon  motion  pictures  in  a 
PATENTS  SUPPLIED  AT  10c  EACH. 


new  and  improved  manner.  It  repre- 
sents an  advance  over  other  methods 
in  that  a  permanent  background 
is  used  instead  of  a  number  of  them, 
and  the  scene  is  moreover  painted 
or  sketched  on  a  properly  prepared 
glass  plate.  The  artist  can  thus 
prepare  a  scene  or  figures  on  either 
side  of  the  glass,  and  suitable 
illumination  "is  provided  to  enable 
him  to  do  so.  Special  illuminating 
screens   are   employed  as  shown. 


Electric  Dancing  Doll 

(No.  1,238,786;  issued  by  Joseph 
Kershaw.) 
This  is  a  particularly  ambitious 
electrical  toy  in  the  form  of  a  minia- 
ture metal  doll  which  is  supported 
on  a  crosswise  shaft  in  the  manner 


illustrated.  A  small  motor  mounted 
in  the  base  of  the  toy  connects  with 
the  revoluble  shaft  by  means  of  a 
belt;  the  motor  circuit  being  periodi- 
cally made  and  broken  at  the  proper 
instants,  by  the  contact  disc  and 
brushes  carried  on  one  end  of  the 
shaft.  When  the  skip  rope  reaches 
the  downward  position,  the  toy  fig- 
ure is  pulled  upwards  by  means  of 
the  solenoid  concealed  in  the  skirt. 


Electrical  Piano 

(No.    1,233,306;    issued   to  George 
Breed.) 

This  is  one  of  the  cleverest  elec- 
trical piano  ideas  we  have  seen.  The 


music  strings  are  supported  in  the 
usual  manner  as  indicated.  At  a 
point  along  each  string  is  placed  an 
electro-magnet  which  starts  _  the 
string  vibiating  when  its  circuit  is 
closed  by  the  key  contact  shown. 
Included  in  this  circuit  is  a  special 
tuned  interrupter  or  pulsator  near 
the  top  of  the  string. 


November,  1917 


THE  ELECTRICAL  EXPERIMENTER 


481 


Under  this  heading  are  publisht  electrical  or  mechanical  ideas  which 
our  clever  inventors,  for  reasons  best  known  to  themselves,  have  as  yet 
not  patented.  We  furthermore  call  attention  to  our  celebrated  Phoney 
Patent  Offtzz  for  the  relief  of  all  suffering  daffy  inventors  in  this  country 
as  well  as  for  the  entire  universe. 

We  are  revolutionizing  the  Patent  business  and  OFFER  YOU  THREE 
DOLLARS  ($3.00)  FOR  THE  BEST  PATENT.  If  you  take  your  Phoney 
Patent  to  Washington,  they  charge  you  $20.00  for  the  initial  fee  and  then 


Phoney  Patents 


you  haven't  a  smell  of  the  Patent  yet.  After  they  have  allowed  the  Pat- 
ent, you  must  pay  another  $20.00  as  a  final  fee.  That's  $40.00!  WE 
PAY  YOU  $3.00  and  grant  you  a  Phoney  Patent  in  the  bargain,  so  you 
save  $43.0011  When  sending  in  your  Phoney  Patent  application, 
be  sure  that  it  is  as  daffy  as  a  lovesick  bat.  The  daffier,  the  better. 
Simple  sketches  and  a  short  description  will  help  our  staff  of  Phoney 
Patent  examiners  to  issue  a  Phoney  Patent  on  your  invention  in  a 
jiffy.   


PHONEY  PATENT  OFFIZZ 


Prize  Winner.  SUBMARINE  KILLER.  Shark  Carries  High  Explosives  in  Tank  Strapt  to  His  Back.  Extensiom  Beam  Carries  Fish-Bait 
in  Front  of  His  Nose.  This  Makes  Him  Speedy  Trying  to  Catch  Fish.  Inverted  Marine  Glasses  Make  Submarine  Appear  Like  Small  Fish. 
He  Rushes  for  it — Contact  Nose  Piece  Operates  Spark  Coil,  Which  Blows  Up  the  Tank.  Sub.,  Shark  and  All.    Inventor,  John  P.  Buckley, 

Washington,  D.  C. 


GEARED 
RUDDER 
POST 


SELF-PROPELLED  BOAT.  Water  Enters  Ship's  Bow  Thru  Inlet,  Leaving  it  by  Outlet,  Incidentally  Driving  Water  Turbine.  The  Latter  Drives 
Air  Compressor,  Which  Runs  Air  Engine  and  This  Drives  the  Dynamo.   The   Latter  Charges  Storage  Battery  Which   Runs  Motor.  Motor 
Operates  Ship's  Propeller,  Thus  Ship  Will  Never  Run  Out  of  Power.    Inventor,  Thomas  Stewart,  Jersey  City,  N.  J. 


482 


THE  ELECTRICAL  EXPERIMENTER 


November,  1917 


Question  Box 


This  department  is  for  the  sole  benefit  of  all  electrical  experimenters.  Questions  will  be  answered  here  for  the  benefit  of  all,  but  only 
matter  of  sufficient  interest  will  be  publisht.    Rules  under  which  questions  will  be  answered: 

1.  Only  three  questions  can  be  submitted  to  be  answered. 

2.  Only  one  side  of  sheet  to  be  written  on;  matter  must  be  typewritten  or  else  written  in  ink,  no  penciled  matter  considered. 

3.  Sketches,  diagrams,  etc.,  must  be  on  separate  sheets.  Questions  addrest  to  this  department  cannot  be  answered  by  mail  free  of  charge. 

4.  If  a  quick  answer  is  desired  by  mail,  a  nominal  charge  of  25  cents  is  made  for  each  question.  If  the  questions  entail  considerable  re- 
search work  or  intricate  calculations  a  special  rate  will  be  charged.   Correspondents  will  be  informed  as  to  the  fee  before  such  questions  are 

answered.  :  , 


RADIO  TELEPHONE  RECEIVER 
TRANSFORMER. 

(853.)  Willi,  i  Reeve,  East  Boston, 
Mass.,  desires  dau  for  building  a  radio  tele- 
phone receiver  tiansformer. 

A.  1.  Relative  to  data  on  radio  telephone 


How  Telephone  Receiver  Transformer  Is  Con 
nected  in  Radio  Detector  Circuit. 


receiver  transformer  we  advise  as  follows: 
The  annealed  iron  wire  core  should  be 
made  of  small  size  stock.  It  may  measure 
54  of  an  inch  in  diameter  by  3  inches 
long.  The  primary  coil  to  be  connected  to 
the  detector  circuit  consists  of  %  pound  of 
No.  39  B  &  S  single  silk  covered  magnet 
wire.  The  secondary  coil  to  be  connected 
to  the  140-ohm  receivers  comprises  1/16 
pound  of  No.  34  B  &  S  single  silk  covered 
magnet  wire. 


ALTERNATING  CURRENT 
QUERIES. 

(854.)  Albert  H.  Beiler,  New  York, 
asks : 

Q.  1.  Will  you  please  inform  me  whether 
a  polarity  changing  current  has  the  same 
effect  as  an  alternating  current?  By  polarity 
changing  current  I  mean  a  current  that 
changes  at  regular  intervals ;  not  gradually 
increasing  or  decreasing  from  positive  to 
negative  following  a  sine  curve ;  but  one 
that  would  be  produced  by  a  pole  changer 
or  a  reversing  switch  actuated  at  regular 
intervals.  Would  such  a  current  if  re- 
versed rapidly  enough,  operate  a  trans- 
former or  induction  coil,  and  would  it  have 
the  same  effect  on  a  magnet  as  a  true  A.  C. 
which  produces  a  field  that  repels  a  copper 
or  aluminum  ring?  It  is  this  latter  point 
I  am  particularly  interested  in. 

A.  1.  A  polarity  changed  current  has  not 
the  same  effect  upon  electrical  apparatus  as 
that  of  an  alternating  current.  However, 
such  a  current  can  be  employed  to  operate 
a  transformer  but  not  an  induction  motor. 
We  doubt  very  much  whether  a  rapidly  re- 
versed current  would  give  the  same  results 
with  the  repulsion  of  aluminum  or  copper 
as  those  obtained  with  the  use  of  a  true 
sine  wave  A.  C.  There  is  no  doubt  how- 
ever, that  some  results  of  a  trifling  nature 
can  be  obtained  by  a  rapidly  reversed  cur- 
rent. 

Q.  2.  According  to  the  capacity  effect  in 


an  alternating  current,  the  capacity  react- 

1 

ance  is  exprest  as  follows:  X  =   ; 

2  T  f  c 

1 

X  therefore  varies  as  .    Now  since  the 

c 

capacity  effect  tends  to  throw  the  voltage 

pllllllllllllllllllllllllllllllllllllllll 

B    ODD  PHOTOS  WANTED  m 
AT  $1.00  EACH!!!  ■ 

g  Now  is  the  time  to  make  your  S 
H  Kodak  pay  for  itself  in  a  real  practi-  jj 
H  cal  way.  We  are  after  interesting  g 
§j  photographs  of  out-of-the-ordinary  g 
H  electrical,  radio  and  scientific  sub-  g 
B  jects  and  are  willing  to  pay  $1.00  cash 
I  for  every  one  we  can  use.  Please 
.  bear  in  mind  that  for  half-tone  re-  g 
!H  production  in  a  magazine,  a  photo-  |g 
=  graph  should  be  particularly  sharp 
\  and  clear.  Of  course,  if  a  subject  B 
B  happens  to  interest  us  particularly  B 
B  well,  we  can  have  the  photo  retouched.  B 
g  For  the  general  run  of  subjects,  how-  g 
g  ever,  it  does  not  pay  to  go  to  such  g 
H  expense.  Therefore,  please  take  pains  g 
g  to  properly  focus  and  expose  your  g 
g  pictures.  It  often  happens  that  a  g 
B  really  mediocre  subject  well  photo-  jj 
=  graphed  wins  approval  over  an  ex-  g 
g  cellent  subject  poorly  photographed.  g 
S  And  don't  send  us  plate  or  film  "nega-  g 
g  tives" ;  send  unmounted  or  mounted  g 
g  "prints,"  preferably  a  light  and  a  dark  g 
g  one. 

g  As  to  what  to  photograph:  Well,  g 
g  that's  hard  for  us  to  say.  We  leave  B 
g  that  up  to  you,  and  every  reader  now  g 
g  has  the  opportunity  to  become  a  re-  g 
B  porter  of  the  latest  things  in  the  realm  g 
B  of  Electricity,  Radio  and  Science,  g 
g  But,  please  remember — it's  the  "odd,  B 
g  novel  or  practical  stunts"  that  we  are  B 
g  interested  in.  Every  photo  submitted  jj 
g  should  be  accompanied  by  a  brief  de-  g 
g  scription  of  100  to  150  words.  Give  g 
B  the  "facts" — don't  worry  about  the  S 
g  style.  We'll  attend  to  that.  Enclose  g 
g  stamps  if  photos  are  to  be  returned 
•    and  place  a  piece  of  cardboard  in  the 

-  envelope  with  them  to  prevent  mutila-  B 
g  tion.  Look  around  your  town  and  jj 
g  see  what  you  can  find  that's  interest-  g 

g  Address  photos  to — Editor  "Odd  g 
B  Photos,"  Electrical  Experimenter,  g 
g  233  Fulton  Street,  New  York  City.  B 

out  of  phase,  it  may  be  likened  to  resistance, 
in  that  the  greater  the  capacity,  the  less 
the  effective  voltage. 

That  means  the  more  capacity  in  a  line 
the  greater  the  resistance,  yet  how  does  this 
reconcile    itself    with    the   above  formula 
1 

where  R  varies  as   ?     Again,  if  my 

c 

reasoning  has  been  wrong  and  the  above 


formula  correct,  why  the  objection  to  a 
great  capacity,  since  it  would  lessen  the  re- 
sistance in  the  conductor. 

A.  2.  The  capacity  reactance  varies  in- 
versely as  the  capacity  and  frequency  of  the 
circuit;  thus  by  increasing  the  capacity  the 
value  of  the  fraction  becomes  smaller,  thus 
the  capacity  reactance  is  decreased  which 
means  that  the  resistance  in  the  circuit  is 
decreased  when  the  capacity  is  increased, 
and  this  is  actually  true.  Since  increasing 
the  capacity  means  an  increase  in  the  stor- 
age of  electricity,  then  a  greater  quantity 
of  electricity  will  be  discharged  per  given 
time  with  an  increase  of  capacity.  The 
current  leads  in  phase  when  there  is  capacity 
reactance  as  you  mention  in  your  question 
and  which  is  true. 

Q.  3.  When  an  inductance  is  connected  to 
an  A.  C.  Circuit,  a  C.E.M.F.  is  generated 
which  is  out  of  phase  with  the  charging 
current.  Why  is  it  said  to  be  ahead  of  the 
current  by  90°,  since  the  current  has  to  flow 
thru  the  inductance  first  before  producing 
the  C.E.M.F.  in  which  case  the  current  is 
ahead?  Why  does  the  inductance  throw 
the  line  voltage  out  of  phase  with  the  line 
current?  It  seems  that  the  C.E.M.F.  only 
is  out  of  phase  with  it,  so  how  does  it 
affect  the  line  E.M.F.  This  same  question 
by  the  way  may  be  put  as  regards  capacity 
where  the  C.E.M.F.  charge  is  out  of  phase 
with  the  charging  current,  but  throws  the 
current  out  of  phase  with  the  line  voltage. 

A.  3.  You  are  well  aware  of  the  fact  that 
whenever  an  inductance  is  placed  in  an  A. 
C.  circuit  that  the  current  will  lag  in  phase, 
but  not  90  degrees,  providing  that  there 
is  sufficient  inductance  to  produce  this  ef- 
fect. It  should  further  be  borne  in  mind 
that  every  centimeter  of  line  conductor  over 
which  the  current  travels  in  the  conductor 
generates  a  counter  -  electromotive  -  force 
which  is  directly  in  opposite  phase  with  that 
of  the  imprest  E.  M.  F.  The  relation  which 
exists  between  capacity  and  inductive  re- 
actance being  that  the  latter  is  directly  pro- 
portional to  the  inductance,  while  the  ca- 
pacity reactance  is  inversely  proportional  to 
the  capacity.  Thus  an  increase  in  induc- 
tance is  a  decrease  in  current,  while  it  is 
vice  versa  with  capacity  reactance. 


QUADRUPLEX  TELEGRAPHY. 

(855.)  Peter  Jolsen,  Wilmington,  N.  C.j 
inquires  for : 


Sounders-^. 


Connections  for  Original    Edison  "Quadru- 
plex"  Telegraph  System. 


November,  1917 


THE  ELECTRICAL  EXPERIMENTER 


483 


Q.  1.  A  wiring  diagram  of  the  original 
Edison  quadruplex  telegraph  ? 

A.  1.  The  diagram  below  gives  the  con- 
nections. 

Q.  2.  In  operating  a  simplex  telegraph 
and  if  it  is  desired  to  know  what  distance 
can  be  covered  with  a  given  equipment 
what  usual  procedure  should  I  follow  in 
regards  to  formulas,  etc.? 

A.  2.  There  is  a  general  formula  which 
will  give  the  maximum  operating  distance 
with  a  given  equipment;  this  formula  is  as 
follows : 

NRr 

1  =  \ 


2R 
Where : 


/NR.- 

^    2LRi  . 

\  2R 

/    R(Ii— L) 

1  = 


N  : 

Rr  : 

R 

Ri; 
It' 


Maximum  transmission  distance  in 
miles. 

Number  of  relays  in  circuit. 
Resistance  of  each  relay  in  ohms. 
Resistance  of  line  per  mile. 
Current  in  amperes  which  will  just 

cause  trip  of  relay  armature. 
Insulation   resistance  per  mile  in 

ohms. 

Current  in   amperes  necessary 
actuate  relay. 


to 


INDUCTANCE  CALCULATION. 

(856.)    T.  Cass,  Toronto,  Ont,  writes: 
Q.  1.  Please  note  these  drawings  of  two 
different  aerials.    Could  you  find  space  in 


Two    Forms    of    Radio    Antennae  Which 
Querist  Shows.   He  Wishes  to  Know  Which 
is  the  Best  of  the  Two. 

vour  next  publication  of  the  "E.  E."  to  in- 
form me  which  will  give  the  best  results  in 
Wireless  Telegraphy?  Each  aerial  contains 
two  hundred  feet  of  copper  wire,  as  you 
will  see  by  the  measurements. 

A.  1.  Both  types  of  aerial  which  you  sub- 
mit are  satisfactory.  However,  the  first 
aerial,  No.  1,  will  be  more  suitable  for  re- 
ceiving purposes,  while  the  second  one,  No. 
2,  is  more  efficient  for  transmitting. 

Q.  2.  How  do  you  calculate  the  induc- 
tance of  a  coil  in  centimeters? 


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THE  ELECTRICAL  EXPERIMENTER 


November,  1917 


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A.  2.  We  should  refer  you  to  a  series  of 
articles  published  in  the  March,  April  and 
September  1917  issues  of  this  journal  which 
cover  the  subject  of  the  calculation  and 
measurement  of  inductance  very  completely. 
These  copies  can  be  obtained  at  15  cents 
per  copy  from  our  "Circulation  Depart- 
ment." 


EARTH  VERSUS  AERIAL 
CURRENTS. 

(857.)  A.  Kramer,  Philadelphia,  Pa., 
asks : 

Q.  1.  Where  do  earth  currents  originate? 

A.  1.  Earth  currents  originate  from  many 
sources,  two  of  which  are  the  chemical  re- 
action between  certain  metals  and  acids  or 
alkalies  which  are  present  in  the  ground. 
Another  phenomenon  which  results  in  earth 
currents,  is  the  variation  of  the  magnetic 
field  of  the  earth,  which  causes  electric  cur- 
rents to  be  generated  in  metals  present  in 
the  earth.  Altho  this  phenomenon  does  not 
occur  in  every  part  of  the  earth,  yet  there 
are  several  places  where  this  action  was 
noted. 

Q.  2.  Could  earth  currents  be  properly 
termed  aerial  currents? 

A.  2.  No.  Both  of  these  currents  are  en- 
tirely different  from  each  other.  The  latter 
type  of  current  is  generated  by  the  action 
of  water  and  dust  particles  floating  in- the 
upper  air  strata. 


COMPOSITION  FORMULA. 

(858.)  Joaquin  Agusty,  San  Juan,  Porto 
Rico,  wants  to  know : 

Q.  1.  I  have  a  stove  made  of  the  common 
coil  resistances,  built  by  The  National  Elec- 
tric Co.,  of  Chicago,  and  the  base  is  made 
of  a  composition  or  paste,  very  hard,  which 
never  broke  with  the  hottest  tests  and  is  a 
very  good  insulator.  It  has  a  reddish 
brown  color  and  looks  as  if  made  of  as- 
bestos and  cement.  It  appears  as  if  it  had 
been  melted  in  a  mould  before  dry  to  make 
it  any  form  desired.  I  want  to  know  the 
composition  of  such  paste. 

A.  1.  We  are  unable  to  give  you  the  exact 
composition  of  the  substance  in  question. 
However,  several  of  these  materials  have 
been  made  with  a  porcelain  compound  in- 
termixed with  another  material  which  with- 
stands sufficient  heat. 

Q.  2.  What  is  the  composition  for  the 
making  of  phonograph  records,  such  as  the 
Edison  type.  Could  the  Edison  cylindrical 
records  be  employed  as  tubes  for  spark 
coils,  and  flat  disc  type  record  as  bases  for 
electrical  apparatus? 

A.  2.  Phonograph  records  are  made  from 
a  composition  of  wax,  tar  and  a  rubber 
compound.  The  exact  percentage  of  these 
ingredients  is  kept  secret.  Another  secret 
compound  is  composed  of  shellac  and  finely 
powdered  mica,  compressed  hydraulically 
into  the  desired  form,  heat  being  applied 
during  the  compression  process.  Phono- 
graph discs  are  unsuitable  for  building 
electrical  apparatus  as  they  are  very  brittle 
and  are  poor  electrical  insulators. 

Q.  3.  How  many  pounds  of  No.  24  D.S.C. 
magnet  wire  will  be  necessary  for  the 
primary  of  a  loose  coupler  of  10,000  meters 
wave  length?  How  many  pounds  of  No. 
32  D.S.C.  magnet  wire  will  be  necessary  for 
the  secondary? 

A.  3.  Two  and  a  half  pounds  of  No.  24 
D.S.C.  wire  will  be  required  for  the  primary 
and  lyi  lbs.  of  No.  32  for  the  secondary. 


POWER  PLANT  QUERY. 

(859.)    Allen  W.  Strete,  Ohio,  writes: 
Q.  1.  Am  unfortunate  enough  to  be  with- 
out commercial  current  as  I  live  in  the 
country.    Advise  me  as  to  what  would  be 
the  cheapest  form  of  current  to  use  for 


experimental  purposes,  batteries  or  a  small 
engine  and  a  dynamo? 

A.  1.  We  would  advise  you  to  employ  a 
small  gasoline  engine  to  drive  a  direct  cur- 
rent dynamo,  so  as  •  to  charge  a  storage 
battery  from  which  you  can  derive  the 
proper  electrical  energy  for  experimental 
work.  The  dynamo  should  be  wound  to 
have  a  potential  of  10  volts  and  20  amperes. 

Q.  2.  What  kind  of  batteries  are  the 
cheapest  in  the  long  run,  dry  cells,  gravity 
or  storage? 

A.  2.. Storage  batteries  are  most  service- 
able, .all  things  considered. 


TWO  INCH  SPARK  COIL  FOR 
RESONATOR. 

(860.)  R.  O.  Sutherland,  South  Bend, 
Ind.,  asks : 

Q.  1.  Will  a  good  2  inch  wireless  coil 
with  mechanical  interrupter  operate  the 
small  Resonator  shown  in  Fig.  1  of  Dr. 
Strong's  last  article  "Electricity  and  Life"? 

A.  1.  It  will  operate  the  resonator,  but 
not  at  its  full  strength. 

Q.  2.  If  not,  will  it  operate  the  small 
Tesla  coil  shown  in  his  previous  article  in 
the  May  issue? 

A.  2.  Yes,  it  will  easily  operate  the  small 
Tesla  coil  to  its  full  strength. 

Q.  3.  Is  a  rotary  spark  gap  necessary  to 
produce  best  results  when  a  high  speed  vi- 
brator interrupter  is  used? 

A.  3.  It  is  not  exactly  necessary  but 
far  better  results  will  be  obtained  by  its  use, 
as  the  oscillatory  circuit  of  the  condenser 
and  primary  df  the  resonator  is  made  to 
oscillate  at  a  greater  period,  which  increases 
the  oscillatory  value  in  the  secondary  of 
the  resonator. 


BOOK  REVIEW^  « 


The  Emission  of  Electricity  from  Hot 
Bodies.  By  Prof.  O.  W.  Richardson, 
F.R.S.  Cloth  bound ;  6  by  9  inches ;  304 
pages,  35  illustrations.  Price,  $2.75.  Pub- 
lished by  Longmans,  Green  &  Co.,  New 
York  City,  N.-Y. 

The  student  of  electro-physics  who  desires  to 
learn  all  about  the  basic  how  and  why  of  the 
emission  of  electricity  from  the  hot  bodies  will 
do  well  indeed  to  study  this  authoritative  work 
by  Prof.  Richardson,  who  has  done  considerable 
work  in  this  field.  The  opening  chapters  treat 
on  the  theory  of  ions,  the  specific  charge  of  the 
ions,  apparatus  used  in  experimental  determina- 
tions of  the  charge,  the  electron  theory,  the  kinetic 
theory,  the  quantum  theory,  the  contact  difference 
of  potential,  etc.,  etc. 

The  author  then  proceeds  to  discuss  the  tem- 
perature variation  of  electronic  emission,  the  ef- 
fect of  gases  on  the  emission  of  electrons,  the 
kinetic  energy  of  the  emitted  electrons  (with  vari- 
ous graphs,  formulae  and  tables),  the  emission  of 
positive  ions  by  hot  metals,  the  specific  charge 
and  electric  atomic  weight  of  the  ions,  the  effect 
of  gases  on  positive  ions,  the  emission  of  ions  by 
heated  salts,  ionization  and  chemical  action,  et 
cetera.  It  is  a  masterly  and  thoro  treatment  of 
the  subject. 


Chemistry  in  the  Service  of  Man.  By 
Dr.  Alexander  Findlay.  Cloth  covers ; 
size  5^x8%  inches;  255  pages;  illus- 
trated. Price,  $1.60  net.  Publisht  by 
Longmans,  Green  &  Company,  London 
and  New  York. 

Not  since  the  late  Robert  Kennedy  Duncan's 
book  on  "The  New  Knowledge"  and  "Modern 
Chemistry"  has  anything  appeared  in  this  same 
vein  covering  the  advances  and  present  status  of 
Chemistry  until  the  interesting  volume  by  Dr. 
Findlay,  compiled  from  his  lectures  for  the  United 
Free  Church  College  and  given  us  in  this  book. 
It  will  be  of  particular  interest  to  readers  who 
make  no  particular  claim  to  chemical  knowledge. 

Written  from  a  British  viewpoint,  it  gives  us 
a  mental  yard  stick  by  which  we  can  gage  the 
great  progress  that  both  English  and  American 
chemists  have  made,  particularly  in  the  last  few 
years. 


You  benefit  by  mentioning  "The  Electrical  Experimenter"  when  writing  to  advertisers. 


November,  1917 


THE  ELECTRICAL  EXPERIMENTER 


485 


Special  attention  is  called  to  the  chapter  on 
Velocity  of  Reactions  and  Catalysis  as  having  two 
viewpoints  for  consideration  which  will  surely 
govern  future  chemistry  on  the  comparison  that 
man  in  his  laboratory  resorts  to  high  temperatures, 
powerful  and  corrosive  reagents,  crude,  cumber- 
some and  noisy  apparatus,  while  nature  building 
(he  most  complex  compounds  makes  them  noise- 
lessly, smoothly,  and  usually  at  the  ordinary  tem- 
peratures. 

On  the  importance  of  the  "Infinitesimal  to  the 
Finite."  Dr.  Findlay  states  in  this  relation  that 
in  Astronomy  one  deals  with  magnitudes  so  vast 
as  to  be  beyond  the  grasp  of  our  minds;  in  the 
domain  of  catalysis  the  magnitudes  in  some  cases 
are  so  small  that  it  becomes  equally  impossible 
to  form  a  true  conception  of  them. 

A  subject  of  particular  interest  will  be  found 
under  the  heading  of  "Cellulose  and  Cellulose 
Products." 

There  are  interesting  chapters  covering  the  elec 
tro-chemic  products,  such  as  the  manufacture  of 
chlorin,  caustic  soda,  aluminium,  grafite,  etc.,  as 
also  chapters  on  Colloids  and  Synthetic  Chemistry. 


Laboratory  Manual  of  Inorganic  Chem- 
istry for  Colleges.  By  Dr.  Lyman  C. 
Newell  of  Johns  Hopkins.  Cloth  covers ; 
size  5x7lA  inches ;  240  pages ;  illustrated. 
Price,  $0.64  net.  Publisht  by  D.  C.  Heath 
&  Company,  New  York. 

This  manual  is  to  be  used  to  accompany  any 
standard  text-book  in  Chemistry  and  particularly 
the  author's  work  entitled  "A  Course  in  Inorganic 
Chemistry  for  Colleges."  It  can  be  commended  as 
being  well  edited,  and  the  illustrations  of  apparatus, 
etc.,  have  been  carefully  considered. 

The  subject  matters  themselves  are  quite  com- 
plete, but  the  attitude  of  the  author,  taken  par- 
ticularly in  the  questions  asked,  are  not  conducive 
to  the  best  kind  of  thinking. 

However,  this  appears  to  be  a  very  valuable 
little  text-book  for  the  laboratory,  as  its  form  is 
such  that  it  is  unnecessary  for  the  student  to  do 
any  re-reading,  while  it  is  sufficiently  full  to  cover 
all  preliminary  work  necessary.  The  field  that  it 
covers  is  quite  large,  but  not  so  great  as  to  make 
it  appear  a  brief  of  larger  treatises  of  the  same 
type. 


The  Nature  of  Matter  and  Electricity. 
By  Comstock  and  Troland.  Cloth  cov- 
ers; size  5^x8  inches;  203  pages,  illus- 
trated. Generously  supplied  with  tables 
and  references.  Price,  $2.00  net.  Pub- 
lisht by  D.  Van  Nostrand  Company,  New 
York  City.  1917. 

This  book  purposes  to  be  an  outline  of  modern 
views  on  the  nature  of  matter  and  electricity.  In 
reality  it  is  an  attempt  to  popularize  these  modern 
ideas,  with  the  usual  result  that  it  is  neither  scien- 
tific or  popular.  It  is  too  bad  that  a  man  like 
Serviss  could  not  be  called  in  to  really  popularize 
such  important  subjects  which  no  doubt  are  of  con- 
siderable interest  to  the  scientific  laity.  Particu- 
larly th''  analogies  are  not  very  good,  and  unless 
an  analogy  helps  to  very  clearly  illustrate  the 
point,  it  is  very  often  better  to  stick  to  the  idea 
itself. 

The  book  can  be  recommended  for  one  thing, 
that  the  references  from  which  the  different  chap- 
ters have  been  taken  have  not  been  omitted  and 
these  would  be  of  considerable  help  to  the  student 
or  to  the  scientist  who  would  want  a  convenient 
source  of  reference  on  the  several  subjects  touched 
on  in  this  volume. 


X-Rays.  By  G.  W.  C.  Kaye,  M.A.,  D.Sc. 
Cloth  covers;  size  5^x8^  inches;  285 
pages,  illustrated.  Price,  $3.00.  Publisht 
by  Longmans,  Green  &  Co.,  of  New  York 
and  London. 

Dr.  Kaye's  second  edition  of  X-Rays  is  a  book 
to  be  commended  to  any  one  interested  in  this 
absorbing  subject.  Not  alone  are  the  X-Rays 
treated  on,  but  the  book  covers  the  phenomena 
of  a  Discharge  Tube,  Cathode  Rays,  Positive  Rays, 
and  some  very  complete  data  on  the  construction 
of  X-Ray  Tubes.  It  is  a  pleasure  to  know  that 
the  scholar  of  J.  J.  Thompson  has  remembered 
his  saying  that  "When  measurement  commences 
science  begins,"  and  the  reader  will  find  that 
nearly  every  subject  handled  by  Dr.  Kaye  carries 
with  it  data  relative  to  measurement,  making  for 
a  very  clear  understanding,  even  tho  the  reader 
may  not  be  interested  from  that  exact  viewpoint. 

This  book  is  a  good  example  of  the  possibilities 
of  interweaving  personalities  with  scientific  data, 
and  thruout  this  volume  the  personal  touch  is  very 
evident. 

It  _  is  a  book,  not  only  for  the  scientist  and 
physicist  who  is  interested  in  this  subject,  but  also 
for  a  great  number  of  professional  men  who  are 
using  or  are  in  direct  contact  with  this  field. 

The  Appendix  is  well  indexed  and  contains  some 
very  valuable  tables  and  data. 

It  can  be  well  recommended  as  the  best  book  in 
the  English  language  on  the  subject  of  X-Rays. 


(Continued  from  page  451) 
Radium  deposit  is  26  minutes ;  for  Actini- 
um deposit — 34  minutes  and  for  Thorium 
deposit — 10.5  hours. 

The  active  deposits,  when  heated  on  a 


Showing  the  Separation  of  the  Three  Entirely 
Different  Types  of  Radium  Emanation  Rays 
in  a  Strong   Magnetic  Field. 

platinum  wire  or  dish,  volatilize  before 
white  heat  and  are  redeposited  on  the  cool- 
er bodies  in  the  neighborhood.  Rutherford 
also  demonstrated  that  induced  activity 
could  be  concentrated  on  the  negative  elec- 


F/jg.l 


f/me  /o  days 


Decay  Curve  for  Radium  Emanation. 

trode  in  a  strong  electric  field,  indicating 
that  the  radioactive  carriers  have  a  posi- 
tive charge.  The  distribution  of  the  active 
deposit  in  a  gas  at  low  pressures  has  been 
investigated  by  Makower  and  Russ. 
— Photos  courtesy  of  "Radium  L't'd." 
(To  be  concluded) 


Radio-active 
Matter 


Magnet- 


Normal  pathjif  rays 


,     ~  V~~-  — 
L. — .  Def/ecf/en  dm 
to  magnetic 
fores 


Fig  2 


® 


Magnetic   Deflection  of  Rays. 


Re/of ive  Penefrob/t/fy  of  fiays 


Relative  Penetrability  of  Radium  Emanation 
Rays. 


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THE    CAUSE    AND    NATURE  OF 
MAGNETIC  CURRENTS. 

(Continued  from  page  455) 
be  moving  in  the  same  direction  and  will 
re-enforce  each  other.* 

The  formation  of  an  electromagnet  is 
now  easily  and  simply  explained.  As  has 
been  seen,  a  wire  bearing  a  current  draws 
the  surrounding  ether  towards  it  from  all 
sides.  If  the  wire  is  coiled,  the  ether  is 
drawn  toward  the  wire  of  the  coil  from 
both  inside  and  outside.  The  supply  of 
ether  outside  the  coil  is  practically  unlim- 
ited, but  within  the  coil  the  supply  is  lim- 
ited. Part  of  this  ether,  as  seen  in  the  ex- 
periment with  a  wire  bearing  a  current, 
is  repelled  from  the  wire  and  part  is  drawn 
along  with  the  current  in  the  wire  and  is 
carried  outside.  The  result  is  the  forma- 
tion within  the  coil  of  a  more  or  less  com- 
plete ether-vacuum  within  the  coil.  Into 
this  ether-vacuum  the  surrounding  ether 
rushes  just  as  air  rushes  into  an  air  vacuum. 
If  the  currents  rushing  into  the  ether- 
vacuum  were  not  moving  from  both  direc- 
tions the  point  of  greatest  vacuum  would 
naturally  be  at  the  center  of  the  inside  of 
the  coil;  but  as  these  currents  are  coming 
from  both  directions  the  result  is  a  partial 
compression,  or,  more  properly  less  of  an 
ether-vacuum,  at  the  center  than  at  points 
midway  between  the  poles  and  the  center. 
Hence  the  greatest  lateral  "attraction"  or 
pressure  is  a  point  between  the  center  of 
the  coil  and  the  poles.  This  has  been  shown 
by  preceding  experiments  to  be  exactly  the 
condition  existing  in  a  magnet.  Currents 
from  the  inside  of  the  coil  at  the  central 
point,  on  account  of  a  partial  excess  of 
ether  at  this  point,  passing  thru  the  wire 
join  currents  from  the  outside  meeting  at 
the  external  center  of  the  coil  form  a 
neutral  or  repulsive  point  which  has  already 
been  noted  in  the  magnet  and  proven  to 
exist  by  the  field  of  iron  filings  and  the 
photographic  plate. 

Attraction  and  repulsion  hardly  need  ex- 
plaining. If  two  magnets  or  coils  are  placed 
so  that  the  north  pole  of  one  is  over  the 
south  pole  of  the  other,  the  currents  sur- 
rounding each  will  be  moving  in  the  same 
direction  and  will  be  in  effect  one  continu- 
ous current.  This  will  produce  an  ether- 
vacuum  between  the  two,  for  both  currents 
are  moving  toward  the  poles  of  their  re- 
spective magnets  tho  in  the  same  spiral 
direction,  a  continuous  spiral,  and  an  ether- 
vacuum  is  formed  between  them,  just  as  an 
ether-vacuum  is  formed  in  the  coil,  and  the 
two  magnets  or  coils  will  be  drawn  together, 
or  rather  forced  together  by  the  ether 
rushing  towards  them  from  the  opposite 
poles.  If  one  coil  is  now  reversed  and  the 
like  poles  of  the  magnets  are  brought  to- 
gether the  currents  surrounding  will  be 
moving  spirally  in  opposite  directions,  the 
particles  of  ether  drawn  in  from  the  sur- 


•  Note.  The  difference  between  the  upper  and 
the  lower  side  of  the  needle  is  slight  but  even 
this  is  sufficient  to  give  a  preponderance  of  force 
on  the  lower  side  of  the  needle.  In  addition  to 
this  it  must  be  borne  in  mind  that  the  currents 
surrounding  the  needle  extend  to  a  considerable 
distance  from  its  surface  and  thus  give  a  con- 
siderably greater  preponderance  to  the  forces  on 
the  under  side.  This  preponderance  of  force  on 
the  under  side  of  the  needle  increases  the  tend- 
ency of  the  currents  on  the  under  side  of  the 
needle  to  re-enforce  each  other  and  move  in  the 
same  direction  and  this  is  sufficient  to  produce 
the  result. 


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November,  1917 


THE  ELECTRICAL  EXPERIMENTER 


487 


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rounding  ether  will  accumulate  and  the 
excess  of  ether,  in  rapid  motion  in  opposite 
directions,  seeking  to  escape  and  opposing 
each  other  by  their  motion,  will  drive  the 
magnets  apart.  If  two  magnets  are  placed 
side  by  side  with  opposite  poles  together, 
the  currents  between  them  will  be  moving 
in  the  same  direction,  producing  a  vacuum 
and  the  two  will  be  drawn  together.  If 
like  poles  are  placed  side  by  side  the  cur- 
rents will  be  moving  in  opposite  directions, 
a  condensation  will  be  formed,  and  the 
magnets  will  b  repelled. 

Here  two  experiments  heretofore  made 
by  others  may  be  explained.  These  ex- 
periments re-enforce  what  has  already  been 
set  out.  Indeed,  these  experiments  rightly 
understood  are  alone  sufficient  to  prove 
part  of  that  which  has  been  advanced ;  but 
they  have  never  been  understood  and  have 
never  been  so  used. 

A  flexible,  free  wire  bearing  a  current 
coils  itself  about  a  straight  bar  magnet, 
coiling  and  uncoiling  and  recoiling  as  the 
current  is  reversed.  Here  the  currents  of 
ether  drawn  to  the  conductor  simply  force 
the  conductor  to  coil,  uncoil,  and  recoil  in 
such  a  manner  that  the  currents  moving 
toward  the  conductor  are  moving  as  nearly 
as  possible  in  the  same  direction  as  the 
currents  moving  spirally  about  the  magnet. 

If  a  wire  with  its  lower  free  and  plunged 
in  mercury  be  suspended  over  the  north 
pole  of  a  bar  magnet  and  a  current  of  elec- 
tricity be  past  downward  the  wire  will  re- 
volve clock-wise  about  the  magnet.  This 
is  not  a  contradiction  but  an  additional 
proof.  As  seen  in  Figure  10,  the  ether 
currents  moving  toward  and  along  the  wire 
will  be  drawn  inward  by  the  currents  ro- 
tating about  the  poles  of  the  magnet.  This 
will  aid  in  producing  a  greater  ether  pres- 
sure inside  the  circle  described  by  the  end 
of  the  wire,  and  the  wire  will  be  forced 
outward.  Moreover,  the  currents  on  the 
side  of  the  wire  on  which  the  spirals  are 
approaching  will  not  reach  the  wire  but  a 
partial  ether-vacuum  will  be  formed  in 
advance  of  the  wire  while  the  currents 
drawn  in  on  the  other  side  of  the  wire  will 
form  a  condensation.  Thus  the  wire  will 
move  away  from  the  condensation  and 
toward  the  partial  vacuum  and  the  wire  will 
rotate  clock-wise — contrary  to  the  motion 
of  the  currents  about  the  pole  of  the  mag- 
net and  contrary  to  the  motion  of  the  sev- 
eral iron  articles  shown  in  the  previous 
experiment. 

Having  proven  the  old  theories  of  mag- 
netism to  be  absolutely  false,  there  is  no 
reason  why  we  should  not  point  out  their 
absurdities.  It  is  desired  especially  to  call 
attention  to  and  emphasize  these  absurdi- 
ties, because  the  fact  that  these  absurdities 
were  recognized  by  even  the  immature  stu- 
dents of  physics,  started  this  investigation 
in  the  first  place,  and  because  there  are  other 
absurdities  which  we  shall  meet  later ;  and 
if  philosophy  has  promulgated  and  upheld 
absurdities  in  one  case,  it  may  well  have 
done  so  in  other  instances.  It  will  be  well 
to  remember  this  fact. 

As  to  these  absurdities.  In  the  very  na- 
ture of  matter,  molecules  are  spherical.  (A 
little  thought  along  the  lines  of  well  known 
laws  of  matter  will  show  this.  I  do  not 
care  to  take  it  up  here,  but  I  will  discuss 
it  with  anyone  who  desires  to  do  so.) 
Spheres  are  the  most  difficult  of  all  shapes 
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According  to  the  molecular  theory,  every 
molecule  is  in  rapid  motion  and  this  motion 
is  increased  by  raising  the  temperature.  To 


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magnetize  iron,  therefore,  would  be  to  low- 
er its  temperature  by  checking  the  vibra- 
tions of  the  molecules,  while  in  reality  the 
temperature  is  raised  during  the  process  of 
producing  an  electromagnet.  If  the  molec- 
ular theory  is  true,  to  so  change  and  check 
the  molecules,  conceiving  it  to  be  possible, 
would  be  to  disintegrate  the  substance. 

In  the  theory  of  the  molecular  arrange- 
ment of  magnets  it  is  asserted  that  mag- 
nets are  surrounded  by  "lines  of  force," 
"line  of  tension,"  "mere  lines  of  direction," 
"imaginary  lines,  like  lines  of  latitude  and 
longitude,"  not  themselves  in  motion  but 
capable  of  producing  motion.  This  is  con- 
trary to  the  laws  of  work  and  the  laws  of 
conservation  of  energy.  Motion  and  work 
can  only  be  produced  by  motion.  Potential 
energy  must  be  changed  to  kinetic  energy 
before  motion  can  be  produced  or  work 
done. 

in  all  theories  on  magnetism  it  is  as- 
sumed that  there  are  lines  of  force  that 
move  without  motion — or  is  it  "emerge" 
without  motion — from  the  north  pole  and 
"pass  to"  the  south  pole — and  yet  without 
motion — moving  from  the  north  to  the 
south  pole,  yet  without  motion,  being  only 
("lines  of  tension  or  direction."  Here,  too. 
•  we  have  lines  of  force  moving  or  passing, 
and  yet  not  moving,  in  only  one  direction 
but  exerting  equal  force  in  both  directions 
and  doing  equal  work  in  both  directions, 
for  both  poles  "attract"  equally.  Was  a 
more  confusing  and  illogical  conglomera- 
tion ever  put  out  in  the  name  of  science? 
This  is  contrary  to  all  laws  of  force.  It  is 
worse  than  the  wheels  within  wheels  and 
cycles  within  cycles  of  the  old  astronomical 
theories. 

In  the  theories  of  magnetic  induction  it 
is  assumed  that  the  induced  current  is  pro- 
duced by  cutting  lines  of  force  passing, 
or  existing,  between  the  north  pole  and  the 
south  pole  as  between  the  poles  of  a  "U"- 
magnet,  the  lines  always  passing  or  "exist- 
ing," from  the  north  pole  to  the  south 
pole.  As  a  fact,  the  result  is  produced  by 
thrusting  either  pole  of  a  straight  magnet 
into  a  coil  or  withdrawing  it  therefrom. 
Therefore,  if  the  lines  pass,  or  exist,  from' 
the  north  pole,  when  the  coil  is  thrust  down 
upon  this  pole  it  is  moving  in  the  same 
direction  as  the  lines,  when  it  is  withdrawn 
it  is  moving  against  them.  Similarly,  when: 
the  coil  is  thrust  over  the  south  pole  it  is- 
moving  against  the  lines  and  when  it  is 
withdrawn  it  is  moving  with  them.  That 
currents  are  produced  in  both  of  these 
cases  is  self-contradictory,  for  in  two  cases 
the  coil  is  working  against  the  lines  and  in 
two  cases  with  the  supposed  lines.  There- 
fore, opposite  causes  are  producing  the 
same  result.  It  is  not  a  sufficient  answer 
to  say  that  the  direction  of  the  current  is 
changed,  for  the  reason  that  for  half  of 
the  time  the  coil  is  moving  with  the  sup- 
posed lines  and  half  of  the  time  against 
them,  and  in  all  cases  work  must  be  done 
against  force  to  produce  a  reaction. 

In  the  theory  of  magnetism,  when  the 
molecules  are  so-  arranged  as  to  produce 
a  magnet,  the  north  poles  of  all  molecules 
are  in  one  direction  and  all  south  poles  of 
molecules  are  pointing  in  the  opposite  di- 
rection 

Each  molecule  is  then  exerting  force  in' 
the  same  direction,  i.  e.,  a  molecule  at  the 
north  pole  of  the  magnet  exerts  force  upon 
the  one  next  to  it  in  the  direction  of  the 
south  pole  of  the  magnet,  and  so  on  to 
the  final  molecule  at  the  south  pole;  and 
the  molecule  at  the  south  pole  of  the  mag- 
net in  the  same  line  is  exerting  force  on 
a  molecule  next  to  it  in  the  direction  of 
the  north  pole,  and  so  on  to  the  original 
molecule  at  the  north  pole  of  the  magnet. 
Meanwhile,  the  molecule  at  the  north  pole 
is  attracting  iron  and  the  molecule  at  the 
south  pole  is  attracting  iron.    To  a  certain 


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NAME   

ADDRESS   

REFERENCE   


J 


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extent,  at  least,  this  is  the  thought,  as  of 
old,  of  a  man  pulling  himself  over  a  wall 
by  his  boot  straps.  It  sets  at  naught  the 
laws  of  action  and  reaction.  According  to 
this,  too,  the  ideal  magnet  would  be  a  disk 
the  thickness  of  two  molecules,  for  here 
there  would  be  no  waste  energy.  The  in- 
termediate molecules  are,  in  the  theoretical 
magnet,  merely  holding  together,  or  rightly 
aligned,  the  molecules  at  the  poles.  This  is 
contrary  to  known  facts.  Besides,  the  thin 
disk  composed  of  two  layers  of  molecules, 
if  such  a  thing  were  possible,  is  the  most 
difficult  of  all  forms  to  magnetize.  More- 
over, a  chain  is  no  stronger  than  its  sepa- 
rate links.  The  whole  strength  of  the 
theoretical  magnet,  then,  is  represented  by 
the  strength  of  the  molecules  on  the  face 
of  the  cross-section  of  its  poles.  That  is, 
a  thin  layer  of  tiny  molecules,  so  small 
ast  to  be  invisible  under  the  most  powerful 
microscope,  are  capable  by  some  mystic 
power  within  themselves,  of  lifting  pounds 
and  tons  of  weight.  This  is  an  explanation 
.that  does  not  in  any  sense  explain. 

A  solenoid  is  a  magnet.  Place  an  iron 
core  within  it  and  it  becomes  a  stronger 
electromagnet.  According  to  the  molecular 
arrangement  theory,  billions  of  molecules 
must  be  changed  from  their  normal  posi- 
tion, and  the  action  must  be  upon  billions 
more  molecules  than  there  are  in  the  effec- 
tive molecules  at  the  poles  of  the  magnet. 
All  of  this  is  waste  energy.  Yet  this  enor- 
mous waste  of  energy  makes  the  magnet 
stronger.  This  is  contrary  to  the  laws  of 
energy. 

As  stated  above,  a  great  amount  of 
energy  is  exerted  in  arranging  the  mole- 
cules of  an  electromagnet.  When  these 
molecules  are  thus  arranged  they  are  placed 
opposite  poles  together  and  as  they  mutual- 
ly attract  each  other  they  will  cling  to- 
gether. Yet  if  the  core  is  soft  iron  the 
moment  the  current  in  the  coil  is  broken 
some  mysterious  force  overcomes  the  force 
which  arranged  them  pole  to  pole  and  the 
force  of  the  mutual  attraction  of  these  bil- 
lions of  molecules,  they  rearrange  them- 
selves contrary  to  all  laws  of  magnets  and 
the  iron  ceases  to  be  a  magnet.  This  is 
the  height  of  absurdity. 

Finally,  an  electromagnet  is  produced  by 
the  passage  of  an  electric  current  thru  a 
solenoid  containing  an  iron  core.  Remove 
this  iron  core  and  the  solenoid  is  still  a 
mas-net.  But  here  there  are  no  molecules 
to  be  arranged  pole  to  pole,  for  there  are 
no  molecules  present,  and  the  whole  theory 
of  the  molecular  arrangement  of  magnets 
falls  to  the  ground. 

Finis. 


ACTION  AT  A  DISTANCE  AS  EXHIB- 
ITED IN  SELENIUM  CRYSTALS. 

(Continued  from  page  459) 
transmitted  much  in  the  same  way  that  a 
sound  wave  is  transmitted  along  a  steel 
rail. 

However  we  do  not  know  that  the  light 
can  produce  a  vibration  of  the  molecules. 
Each  molecule  of  selenium  has  at  least  one 
electron  loosely  attached  to  it.  This  electron 
probably  has  a  definite  location  with  regard 
to  the  center  of  the  molecule,  when  it  is  not 
disturbed.  If  so  there  must  be  a  space 
lattice  of  electrons  in  the  selenium  crystal 
exactly  corresponding  to  the  space  lattice 
of  the  molecules  shown  in  Fig.  4.  Since 
light  is  an  electromagnetic  phenomenon  we 
can  well  understand  how  the  electrons  in 
the  space  lattice  could  be  set  in  vibration 
and  further  how  these  electrons  by  elec- 
trostatic repulsion  would  set  neighboring 
planes  of  electrons  in  vibration.  When  the 
electrons  are  in  vibration  they  are  more 
easily  removed  from  their  equilibrium  posi- 
tions in  the  molecules  by  a  voltage  across 


CLAIM  ELECTRICITY  PREVENTS 
INSANITY. 

Electricity  as  a  palliative  or  even  a  pre- 
ventive of  insanity  in  its  early  stages  is 
receiving  serious  attention  in  scientific 
circles,  according  to  reports  made  before 
the  annual  convention  of  the  American 
Electro  Therapeutic  Association. 

It  was  said  in  discussion  that  experts 
who  are  specializing  in  electro-therapy 
have  achieved  remarkable  results  in  the 
cure  of  melancholia  and  insomnia  and  the 
restoration  of  normal  mental  activities. 

Most  important  results  have  been  at- 
tained in  the  treatment  of  melancholia  and 
other  cerebral  "disorders"  thru  the  use  of 
galvanic  currents.  Results,  almost,  if  not 
quite  as  encouraging,  have  been  procured 
by  Philadelphians  in  the  correction  of  de- 
fects of  the  vision  by  electricity  after  eye 
experts  had  pronounced  cases  to  be  hope- 
less. 

Dr.  Alfred  T.  Livingston,  of  Jamestown, 
N.  Y.,  warned  the  electro-therapy  spe- 
cialists against  extreme  currents,  declaring 


his  best  results  had  been  obtained  thru 
applying  the  electrode  to  the  base  of  the 
nerve  centers  of  the  brain. 


100,000  MORE  FOR  SIGNAL  CORPS. 

To  fill  the  Army  Signal  Corps,  the  War 
Department  may  decide  to  draft  an  ad- 
ditional 100,000  men.  The  signal  service 
has  asked  for  a  decision  on  the  method  to 
pursue  in  filling  up  gaps,  existing  in  the 
aviation  and  telegraph  branches,  and  the 
general  staff  is  expected  to  answer  in  a 
few  days. 

The  Draft  Law  permits  the  filling  of 
units  which  are  now  below  strength,  but 
it  is  held  that  an  added  100,000  instead 
of  any  of  the  687,000  of  the  original  draft 
would  be  necessary  for  the  Signal  Corps. 

Men  who  join  the  aviation  section  will 
have  a  chance  to  train  either  in  American 
schools  or  in  England,  France  or  Italy. 

England,  it  is  learned,  has  establisht  a 
flying  school  in  Egypt,  which  is  used 
chiefly  by  the  Canadian  corps. 


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November,  1917 


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the  crystal.  Thus  light. increases  the  con- 
ductivity of  selenium  by  lowering  the 
stability  of  the  electrons  in  the  crystal 
structure  and  these  electrons  may  com- 
municate their  state  of  unrest  to  neighbor- 
ing electrons  in  an  almost  human  fashion. 
But  if  this  be  the  explanation,  this  new 
property  of  matter  continues  to  be  about  as 
much  of  a  mystery  as  any  other  action  at 
a  distance. 


EXPERIMENTAL  PHYSICS. 

{Continued  from  page  460) 

passes  outside  of  cardboard  BC.  Seeing 
the  bull's-eye  X  with  one  eye  and  the  sight 
with  the  other  eye,  i.  e.,  seeing  both  the 
bull's-eye  and  the  sight,  he  has  only  to  line 
up  his  sight  to  the  bull's-eye,  pull  the  trig- 
ger, without  flinching,  and  the  bull's-eye  is 
hit  right  in  the  middle,  thus  performing  the 
impossible  (?).  Measuring  the  .  angle 
EX-"e"  one  can  readily  determine  just  how 
small  BC  must  be,  and  for  those  unfamiliar 
with  geometry,  the  correct  size  may  be 
found  by  trial,  beginning  with  a  small  piece 
and  gradually  increasing  the  size  of  the 
cardboard  until  the  largest  is  found  (the 
larger  the  cardboard  the  more  marvelous 
appears  the  feat).  Everyone  owning  an 
air  rifle,  Boy  Scout  rifle  or  other  fire-arm 
should  perform  this  trick  and  learn  to 
mystify  his  friends  by  his  marvelous 
skill??! 

Cut  a  small  piece  of  clear  glass  (pre- 
ferably plate  glass)  so  that  two  of  its  sides 
are  parallel  (MN  and  OP  in  Figure  44). 
Place  the  glass  on  paper  and  draw  line  AB 
up  to  the  side  OP  not  meeting  perpendicu- 
lar. With  eye  close  to  the  table  look  across 
MN  until  the  eye  is  in  line  with  AB.  Draw 
the  line  from  the  eye  to  MN  which  appears 
to  coincide  with  AB  if  produced.  Call  it 
CD.  On  looking  up  you  will  be  surprised 
to  find  that  instead  of  being  in  line  AB,  i,  e., 
EF,  it  will  be  some  distance  away  from  EF 
and  hence  not  in  the  prolongation  of  AB 
at  all.  Remove  the  glass  and  draw  CB. 
Our  line  ABCD,  represents  the  path  over 
which  the  light  in  the  direction  of  AB 
traveled.  We  notice,  therefore,  that  when 
the  ray  of  light  reached  the  glass  at  side 
OP  it  bent  (was  refracted;  see  Lesson  8) 
toward  the  perpendicular  XY,  while  on 
passing  out  from  the  glass  at  MN  it  bent 
away  from  the  perpendicular  WZ.  The  law 
is  stated — "Light  passing  from  a  lighter  to 
a  denser  medium  is  retarded  in  speed  and 
bends  toward  the  perpendicular;  light  pass- 
ing from  a  denser  to  a  lighter  medium  in- 
creases in  speed  and  bends  away  from  the 
perpendicular."  It  is  upon  this  law  that  the 
use  of  all  lenses  and  optical  instruments 
employing  lenses  depends ;  hence  its  im- 
portance cannot  be  overemphasized. 

There  are  two  kinds  of  lenses,  convex 
and  concave.  In  Fig.  45,  lenses  number 
1,  2,  and  3  are  convex ;  4,  5,  and  6  are  con- 
cave. Convex  lenses  curve  outward,  where- 
as concave  lenses  curve  inward.  There  are 
three  types  of  convex  (1)  double,  (2) 
piano,  (3)  concavo  and  three  types  of  con- 
cave lenses  (4)  piano,  (5)  double,  (6) 
convexo.  The  action  of  the  double  convex 
and  double  concave  lenses  is  typical  of 
their  respective  types  and  only  those  two 
will  be  considered  in  what  follows.  It 
should  be  noticed  that  all  convex  lenses  are 
thicker  at  the  middle  than  any  other  place, 
while  all  concave  lenses  are  thicker  at  the 
ends.  Also  because  of  the  above  stated  law 
of  refraction,  light  bends  around  the  thicker 
part  of  the  lens.  The  sun's  rays  and  other 
rays  coming  from  a  great  distance  are  con- 
sidered to  be  parallel.  In  Fig.  46  we  see 
that  when  parallel  light  passes  thru  a  con- 
vex lens  (A)  the  rays  bend  toward  each 
other  (converge)  and  meet  at  a  point  F. 
This  point  is  called  the  focus  of  the  lens, 


and  the  distance  of  this  point  from  the 
center  of  the  lens  is  called  the  focal  length. 
In  the  case  of  the  concave  lens,  Fig.  46 
(B),  we  see  that  the  rays  bend  away  from 
each  other  (diverge)  and  hence  appear  to 
come  from  the  point  F,  on  the  same  side  of 
the  lens  as  the  parallel  light.  This  point 
is  also  called  the  focus  and  its  distance 
from  the  center  is  called  the  focal  length. 
EXPERIMENT  54— 

Altho  the  focal  length  of  a  lens  is  one 
of  its  most  important  properties,  it  is  the 
easiest  to  determine  experimentally.  The 
best  method  of  finding  the  focal  length  of 
a  convex  lens  is  to  place  a  sheet  of  paper 
on  the  ground  and  holding  the  lens  in  the 
hand  move  the  hand  slowly  up  and  down 
until  the  image  of  the  Sun  is  sharply  seen 
on  the  paper.  Measure  the  distance  from 
the  lens  to  the  spot  (Sun's  image)  and  add 
to  it  half  the  thickness  of  the  lens.  In  the 
case  of  a  concave  lens  the  procedure  is 
slightly  different.  The  image  of  the  Sun 
being  on  the  same  side  as  the  Sun  cannot 
be  caught  on  a  screen,  since  the  screen 
would  not  permit  the  rays  to  pass  thru. 
(Also  the  image  is  not  a  real  one,  since  the 
rays  do  not  actually  come  from  F  in  Fig. 
46-B,  but  only  appear  to  come  from  there). 
However,  holding  the  lens  in  front  of  the 
right  eye  a  small  image  of  the  Sun  will  be 
seen  thru  the  lens  at  the  point  F,  (Fig.  47). 
Looking  at  the  tip  of  a  pencil  held  in  the 
left  hand,  move  the  hand  until  with  the  left 
eye  the  pencil  tip  is  seen  to  be  out  from  the 
lens  the  same  distance  as  the  image  of  the 
Sun  is  seen  to  be  with  the  right  eye.  Have 
your  partner  measure  the  distance  from 
the  lens  to  the  pencil  tip  and  add  half  of 
the  thickness  of  the  lens  and  you  have  the 
focal  length. 

In  the  case  of  a  camera  we  have  simply 
to  point  it  at  the  Sun,  get  a  clear  image 
on  the  ground  glass  and  measure  the  dis- 
tance. When  two  or  more  lenses  are  used 
in  combination,  the  procedure  is  the  same 
as  for  a  single  lens.  In  all  these  experi- 
ments a  distant  tree  or  window  or  chimney, 
or  other  object  may  be  used  instead  of  the 
Sun,  but  the  writer  prefers  to  use  the  Sun 
since  it  brings  back  the  days  when  the  focal 
length  was  found  by  him  in  school  using 
the  neck  of  the  boy  seated  in  front  of  him 
as  the  screen.  When  the  boy  began  to 
fidget  and  scratch  his  neck,  the  writer  knew 
that  the  lens  was  a  focal  distance  away 
from  the  neck,  but  then  his  interest  stopt 
when  the  neck  began  to  burn.  Now  we  are 
interested  in  actually  measuring  the  focal 
length.  The  question  arises,  "why  measure 
the  focal  length,  what  good  is  it  when  you 
have  it?"  Just  this: — The  magnifying 
power  of  a  lens  is  equal  to  10  divided  by  the 
focal  length.  (Measured  in  inches.)  The 
magnifying  power  of  a  telescope  is  equal 
to  the  focal  length  of  the  objective  lens 
divided  by  the  eyepiece  lens.  The  magnify- 
ing power  of  the  opera  or  field  glass  is  also 
the  focal  length  of  the  objective  divided  by 
the  focal  length  of  the  eyepiece.  The 
magnifying  power  of  a  compound  micro- 
scope is  equal  to  ten  times  the  length  of  the 
tube  divided  by  the  product  of  the  focal 
lengths  of  the  objective  and  eyepiece.  From 
these  and  many  other  considerations  the 
importance  of  knowing  the  focal  length  of 
a  lens  is  apparent. 

The  readers  should  as  exercises  measure 
the  focal  lengths  of  lens  available  and  com- 
pute the  various  magnifying  powers  accord- 
ing to  the  laws  just  stated.  This  subject 
of  light  is  very  fascinating  and  will  be 
continued  in  the  next  lesson  which  will 
treat  of  "Photography."  The  writer  sin- 
cerely trusts  that  interest  is  aroused  in  the 
reader  and  that  the  reader  will  consult  the 
standard  text-books  for  further  information 
on  the  subject. 

(To  be  continued) 


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November,  1917 


THE  ELECTRICAL  EXPERIMENTER 


491 


Edited  by  H.  GERNSBACK 

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far  as  it  is  possible  to  do  so. 

Should  advice  be  desired  by  mail  a  nominal  charge  of  $1.00  is  made  for  each 
question.  Sketches  and  descriptions  must  be  clear  and  explicit.  Only  one  side  of 
sheet  should  be  written  on. 


ELECTRIC  BULB. 

(176.)  Thomas  Sheehan  of  Duluth, 
Minn.,  has  invented  a  novel  electric  bulb ; 
the  principle  idea  being  to  do  away  with 
the  glass  tip  in  a  certain  manner,  so  that 
it  cannot  be  broken  off  easily.  In  other 
words  it  will  not  project  as  in  the  present 
style  lamps.  He  wishes  to  know  if  this 
idea  is  patentable. 

A.  This  is  indeed  a  very  good  idea — as 
simple  as  it'  is  good.  We  do  not  see  any 
reason,  technically  speaking,  why  the  bulb 
could  not  be  made  in  the  manner  described 
by  our  correspondent,  but  as  a  precaution- 
ary measure,  we  would  advise  our  corre- 
spondent to  get  in  touch  with  a  patent 
attorney  to  make  search  in  the  patent  office 
at  once. 


MUFFLED  BELL. 

(177.)  Paul  B.  Eaton  of  Baltimore, 
Md.,  has  been  reading  about  the  bell 
softener  which  has  been  discust  quite  a 
number  of  times  in  these  columns,  his  idea 
being  to  use  an  ordinary  clock-maker's 
cathedral  gong:  i.e.,  a  wire  gong.  This  is 
usually  made  of  one  piece  of  spiral  steel, 
and  the  sound  given  off  by  this  gong  is 
quite  pleasing.  He  wishes  to  know  if  a 
patent  can  be  obtained  on  this  device. 

A.  The  editor  of  these  columns  has 
been  using  a  device  of  this  kind  for  some 
ten  years,  and  there  is  one  in  our  office 
which  has  been  there  for  quite  a  while. 
There  is  nothing  new  contained  in  the 
application  of  a  bell  clapper  striking  the 
cathedral  gong.  No  patent  could  be  ob- 
tained on  this. 

TELL-TALE  WATER  GAGE. 

(178.)  Mr.  John  Murphy  of  Halifax,  N. 
S.,  submits  to  us  information  about  water 
gage  or  tell-tale.  The  idea  being  to  treat 
the  water  gage  in  such  a  manner  that  when 
the  water  in  the  boiler  is  too  low  or  too 
high  instead  of  using  it  or  inspecting  it,  an 
alarm  bell  will  ring  and  will  continue  to 
ring  until  the  condition  is  remedied. 

Our  correspondent  wants  to  know  if 
such  a  thing  is  practical  and  if  it  can  be 
patented.  Also  if  there  exists  a  demand 
for  this  device. 

A.  While  there  are  several  devices  of 
this  kind  on  the  market,  without  knowing 
what  the  idea  consists  of  it  is  quite  impos- 
sible to  tell  whether  it  is  patentable  or  not. 
Our  advice  is  to  get  in  touch  with  a  patent 
attorney. 


SELENIUM  CELL  DEVICE. 

(179.)  Robert  Knowles  of  Toronto, 
Can.,  has  submitted  a  rather  complicated 
device  whereby  a  gas  jet  cannot  be  lit 
without  introducing  a  lighted  match  thru 
a  certain  opening,  which  in  turn  causes 
selenium  to  act  on  a  relay,  the  latter  open- 
ing the  gas  flow. 

A.   While  this  idea  is  very  ingenuous, 


and  while  we  have  no  doubt  that  a  patent 
can  be  obtained  upon  the  device,  we  do  not 
think  the  idea  is  very  practical ;  at  best 
there  would  be  only  a  very  limited  market 
for  the  device. 


AMPLIFIER. 

(180.)  Clyde  Fitch,  Pittsfield,  Mass.,  has 
invented  an  amplifier  which  is  supposed  to 
work  by  exciting  the  field  of  a  small  alter- 
nator. Several  other  points  of  information 
are  given  as  to  how  this  amplifier  could  be 
made  to  work. 

A.  It  is  impossible  to  state  whether  a  de- 
vice of  this  kind  will  work  without  trying 
it  out.  If  our  correspondent  has  faith 
enough  in  the  idea,  we  advise  having  a 
model  built  for  testing  purposes. 


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492 


THE  ELECTRICAL  EXPERIMENTER 


November,  1917 


.-3-1 


EXPERIMENTERS! 

Student's  Chromic  Plunge  Battery 

HERE  is  a  little  battery  that  will  be  highly  welcomed  by  every  experimenter  all 
over  the  country.  It  is  the  first  low  priced,  as  well  as  fool-proof  chromic  acid 
battery  on  the  market.  It  is  a  little  wonder,  and  for  the  small  price  we  ask  for  it,  it 
stands  unmatched. 

Now,  we  do  not  wish  to  mislead  you,  so  we'll  tell  you  at  the  start  what  this  battery 
WILL  NOT  do.  It  will  NOT  charge  storage  cells,  it  will  NOT  run  a  large  motor  for 
hours,  it  will  NOT  run  a  big  spark  coil.   It  is  NOT  a  very  big  battery. 

BUT  it  is  an  ideal  battery  for  electrical  experimental  work  where  a  very  powerful 
current  is  not  required.  This  battery  will  light  a  2'  volt  lamp  for  several  hours  on  one 
charge;  it  will  run  a  small  toy  motor  surprisingly  well;  it  will  do  small  electroplating 
work;  it  is  ideal  for  testing  work;  it  gives  a  fairly  steady  current,  and  as  the  zinc 
electrode  can  be  pulled  clear  of  the  electrolyte,  no  materials  are  used  when  battery 
stands  idle. 

Only  best  materials  go  into  the  making  of  this  battery.  Best  Amalgam  Zinc  only  is  used,  as  well  as  a 
highly  porous  carbon  to  ensure  a  steadier  current.  Handy  binding  posts  are  used.  We  furnish  enough 
chromic  salts  for  4  charges.  Full  direction  for  operation  and  care  of  battery  are  included.  Each  battery 
tests  2  volts  and  10  amperes  when  set  up  fresh.  Not  over  2  amperes  should  be  drawn  from  battery  continu- 
ously. By  using  six  or  eight  of  these  batteries,  a  great  many  experiments  can  be  performed.  No  solution 
can  run  out  of  this  battery  if  upset  by  accident.  This  makes  it  an  ideal  portable  battery,  such  as  for 
operating  a  bicycle  lamp,  or  as  other  portable  lamp,  where  a  powerful  light  is  not  required,  for  boy  scouts' 
field  telegraph  work,  operating  telegraph  outfits,  etc.,  etc.  Size  over  all  is  5"x2".  Shipping  weight,  1  lb. 
No.  999    Student's  Chromic  Plunge  Battery  SO 


TELEGRAPH  CODES. 


The  "Electro  Telegraph" 
$1.25 


is  not  a  iu.i ,  out  a  practical,  honestly  built  telegraph  outfit,  which  not  only  sounds 
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you  can  become  a  first-class  telegraph  operator.  Such  operators  are  in  big  demand 
now.  Outfit  consists  of  TWO  complete  telegraph  instruments  each  measuring  3%  x 
2%  x  2Y4.  All  metal  parts  are  highly  nickel  plated,  including  key  lever.  Note  hard 
rubber  knob.  Telegraph  Code  Chart,  telegraph  blanks  and  connecting  wire  comes 
with  set,  but  no  batteries.  Outfit  works  on  2  dry  cells  (one  cell  for  each  instrument). 
The  "Electro"  is  the  ON!LY  Outfit  that  works  both  ways,  each  station  can  call ;  no 
switches,  no  extras.  Nothing  to  get  out  of  order.  Guaranteed  to  please  you  or 
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At  all  good  dealers  and  department  stores.  If  your  dealer  cannot  supply  you  send 
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Illuminated  flag,  flashlight 
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DEALERS :  Write  for  our 
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Powerful  permanent  steel 
magnet,  soft  Iron  core,  fibre 
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Hanger  can  be  unscrewed 
and  receiver  will  then  fit 
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SOME  USES.— 

For  all  telephone  work. 
Also  for  making  the  small 
testing  outfits  for  repair 
men  in  circuit  with  only  one  dry  cell  or  flash- 
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This  receiver  is  single  pole;  2%  x  1%  inches; 
wgt.  4  oz. ;  resistance,  75  ohms. 

IF  TWO  OF  THESE  RECEIVERS  ARE  USED, 
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November,  1917 


THE  ELECTRICAL  EXPERIMENTER 


493 


WIRELESS 

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MISTOOK  FAN  FOR  "SPY" 
WIRELESS. 

A  large  electric  fan  on  top  of  the  New 
York  Edison  Company  building  at  Fifty- 
third  street  and  Sixth  avenue,  New  York 
City,  was  taken  for  a  German  wireless  ap- 
paratus by  a  passing  citizen,  and  the  po- 
lice department  was  notified. 

The  man  saw  sparks  coming  from  the 
fan,  which  is  used  to  ventilate  the  build- 
ing, and  told  the  police  that  Teuton  spies 
were  sending  messages.  It  would  pay  all 
of  us  to  study  up  a  bit  on  radio  and  elec- 
trical matters  these  days. 


ELECTRICITY   BEING  USED  TO 
HASTEN  CROPS. 

(Continued  on  page  439) 

together  with  the  periods  of  working  are 
important  factors  in  the  welfare  of  the 
installation.  The  current  expended  at 
Carnarvon  is  economical  in  working.  The 
current  required  at  the  primary  terminals 
amounts  to  450-460  watts  per  acre  per  hour 
(approximately  only  half  a  unit)  ;  the  rea- 
son for  the  discrepancy  is  entirely  atmos- 
pheric, the  energy  required  being  greater  in 
proportion  to  the  prevailing  humidity  to 
make  up  for  the  sundry  current  loss.  This 
occurs  on  dull  heavy  days  when  mist  or 
heavy  dew  prevails,  whereas  on  prevailing 
dry  periods  the  efficiency  is  uniform. 

At  Carnarvon  the  apparatus  is  fixt 
permanently  in  a  small  shed,  and  is  con- 
nected to  the  main  cable  which  supplies 
electric  light  for  the  residence,  the  out- 
buildings and  farm.  The  initial  voltage  is 
220  volts  continuous  current,  and  passes 
thru  a  controlling  switchboard  to  the 
intensifying  apparatus.  The  chief  feature 
of  the  overhead  wiring  is  the  careful  man- 
ner observed  in  insulating  the  wires,  which 
are  suspended  over  the  respective  garden 
plots — a  uniform  height  of  7  feet  has  been 
adopted  in  order  to  allow  freedom  for  the 
garden  staff  to  carry  on  the  work  of  cul- 
tivation when  the  current  is  not  in  use. 

Electroculture  has  past  the  back-gar- 
den, amateur  stage.  It  is  now  a  serious 
proposition.  But  knowledge  of  its  possi- 
bilities and  limitations  is  scanty.  It  falls 
into  place  with  other  possibilities  of  de- 
velopment in  plant  industry,  which  will  only 
reach  fruition  by  the  help  of  well-organ- 
ized, large-scale  research  and  experiment 
supported  by  public  funds. 


CHEMICAL  ACTION  OF  STORAGE 
BATTERIES. 

(Continued  on  page  473) 

If  a  battery  is  allowed  to  stand  on  open- 
circuit  after  charging,  the  electromotive- 
force  falls  in  fifteen  or  twenty  minutes  to 
the  value  corresponding  to  the  density  of 
the  acid.  This  is  due  to  solution  around  the 
plates  becoming  saturated  with  lead  sul- 
fate. On  discharge,  when  the  voltage  has 
fallen  below  the  value  corresponding  to 
the  density  of  the  acid,  standing  on  open 
circuit  brings  it  back  to  normal  value.  In 
this  case  the  recovery,  as  it  is  termed,  is 
due  to  the  diffusion  of  the  sulfuric  acid 
into  the  pores  of  the  plate  where  it  has  be- 
come exhausted. 

If  a  charged  cell  is  permitted  to  stand 
idle,  the  density  of  the  acid  slowly  de- 
preciates, and  the  quantity  of  electricity 
obtainable  from  it  diminishes  from  day  to 
day.  This  is  known  as  the  self-discharge 
of  the  battery,  and  for  a  cell  in  good  con- 
dition amounts  to  from  one  to  two  per  cent 
per  day;  if  impurities  are  contained  in  the 
acid,  it  sometimes  will  amount  to  50  per 


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INTERNATIONAL  CORRESPONDENCE  SCHOOLS 

Box  536  1 ,  SCRANTON,  PA. 

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□  CHEMICAL  F.NCINF.i  It 


□  ELI  CTRICAL  ENGINEER 
M  Electrician 
O  Electric  Wiring 

Q  Electric  Lighting 

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Q  Practical  Telephony 

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□  Gas  Engineer 

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O  Surveying  and  Mapping 

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LJ  Metallurgist  or  Prospector 

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□  ARCHITECT 

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□  PLUMBING  AND  HEATING 

□  Sheet  Metal  Worker 


□  SALESMANSHIP 

□  ADVERTISING  MAN 
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C  Show  Card  Writer 
Q  Outdoor  Sign  Painter 

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n  BOOKKEEPER 

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□  automobiles      □  Italian 


Present 
Occupation. 

Street 

and  No  


You  benefit  by  mentioning  "The  Electrical  Experimenter"  when  writing  to  advertisers. 


494 


THE  ELECTRICAL  EXPERIMENTER 


November,  1917 


iilfl»lri^lli«Hff»afl 


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Impaired  Hearing 


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THE  MICROPHO  JUNIOR  DEAF-PHONE  is  a  super-sensitive  instrument  which 
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device  at  an  extremely  low  price.  It  is  equal  to  any  $35.00  instrument  made  and 
superior  to  most  of  them. 

The  outfit  consists  of  One  Super-Sensitive 
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Sensitive  Ear  Piece  with  small  black  cord ;  One 
Black  Single  Headband;  Black  Case  and  Two 
Batteries.  IMPROVED 


Super-Sensitive  Microphone  Only  $7.50 


This  instrument  is  offered  at  an  extremely  low 
price.  It  is  excellent  fur  building  your  own  radio 
amplifier.  Can  also  be  used  in  many  experiments 
where  a  sensitive  microphone  is  required 

NEW  DETECTAGRAPH  $15 

This  detecting  instrument  of  marvelous  sensitivity 
can  be  used  for  detecting  secret  conversations.  Out- 
fit consists  of  Sensitive  Transmitter,  25  ft.  Black 
Cord,  Receiver,  Headband,  Case  and  Battery. 

Send  for  one  Today  and  Convince  Yourself 
MICROPHO-DETECTOR  COMPANY 
26  Cortlandt  St:,  NEW  YORK 


DETECTAGRAPH  $15 
Gaston  Boissonnault,  President 
Makers  of  Super-Sensitive  Microphone  Apparatus 


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Our  40  years'  experience  enables  us  to  furnish  heating  plants,  CUT  TO  FIT,  bathroom 
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MAGNETIC 
RECTIFIER 

Patented 
April  1916 


F-F  BATTERY  BOOSTER 

FULL  WAVE  — DURABLE  — FOOL  PROOF 

For  Public  or  Private  Use 

Charges  storage  batteries  from  alternating 
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Get  Bulletin  No.  12 

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F.  O.  B.  Cleveland. 
For  25,  SO  and  60  cycle  circuits 

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Jobbers  and  Dealers  Throughout  the  United  States 
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*  1,500  Made  One  Month 

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MORSE  ALSO 

In  addition  to  the  excellent  instruction  in  all 
phases  of  wireless,  we  now  offer  Morse  Telegraphy. 
Folder  "C"  on  request. 

Eastern  District  Y.M.C.A. 

Marcy  Avenue  near  Broadway 
Brooklyn,  N.  Y. 


cent  per  day.  The  self-discharge  of  the 
lead  sponge  plate  is  more  liable  to  occur 
than  that  of  the  peroxid  plate,  because  it  is 
affected  by  a  much  larger  number  of 
causes.  It  is  fatal  for  the  lead  plate  if  the 
acid  contains  any  metal  which  is  more 
electro-negative  than  lead  when  in  con- 
tact with  sulfuric  acid,  for  the  impurity 
would  become  precipitated  on  the  plate  and 
thus  produce  a  short-circuited  local  ele- 
ment. The  lead  would  thereupon  tend  to 
dissolve  and  deposit  hydrogen  on  the  im- 
purity. If  the  over-voltage  of  the  im- 
purity is  not  too  great,  this  would  in  fact 
take  place,  and  the  lead  plate  would  change 
to  sulfate.  The  potential  of  the  cell:  Pb 
sponge.  /  Sulfuric  acid  /  Platinized  Pt  + 
Ha  is  0.33  volt,  hydrogen  being  the  positive 
pole.  A  current  could  be  taken  from  this 
cell  on  closing  the  external  circuit;  lead 
sulfate  would  be  formed  on  the  lead  pole 
and  hydrogen  would  be  deposited  on  the 
positive  pole.  But  if  some  metal  were  to  be 
substituted  for  platinum  for  which  the  over- 
voltage  is  0.33  volt  or  more,  evidently  hy- 
drogen could  not  be  liberated,  and  there- 
fore no  action  would  take  place.  Conse- 
quently only  the  metals  standing  on  the  left 
of  the  following  table  would  be  dangerous 
for  the  accumulator ;  those  on  the  right 
could  exist  as  impurities  in  the  acid  with- 
out the  least  danger,  even  tho  some  of  these 
are  more  electro-negative  than  lead. 

TABLE. 


Over-voltage 

Over-voltage 

Platinized 

Palladium 

0.46 

Platinum 

0.005 

Cadmium 

0.48 

Gold 

0.02 

Tin 

0.53 

Iron 

0.08 

Lead 

0.64 

Platinum, 

Zinc 

0.70 

polished 

0.09 

Mercury 

0.78 

Silver 

0.15 

Nickel 

0.21 

Copper 

0.23 

As  made  apparent  from  this  table,  plat- 
inum is  the  most  injurious  impurity.  It  has 
been  found  that  one  part  of  platinum  in  a 
million  of  acid  will  produce  a  rapid  self- 
discharge  of  the  lead  plate.  It  has  been 
found,  however,  that  metals  when  present 
together  can  produce  a  rapid  self-discharge, 
which  alone  cause  scarcely  any  action.  An 
explanation  of  this  cannot  be  given  at 
present. 

The  self-discharge  of  the  positive  plate 
takes  place  more  slowly  than  that  of  the 
lead  sponge  plate.  Metallic  impurities  are  of 
no  effect  on  the  lead  peroxid,  for  they  would 
not  become  precipitated  upon  it.  The  only 
kind  of  spontaneous  discharge  _  is  due  to 
local  action  between  the  peroxid  and  the 
lead  of  the  support,  which  together  form  a 
short-circuited  element,  and  this  is  of  im- 
portance only  for  plates  with  a  thin  per- 
oxid layer. 

Another  cause  of  self-discharge  of  a  bat- 
tery is  the  presence  of  salts  of  metals  that 
can  exist  in  more  than  one  stage  of  oxida- 
tion. For  example,  an  iron  salt  would  be 
oxidized  to  the  ferric  state  on  the  lead 
peroxid,  and  would  thereupon  diffuse  to  the 
lead  plate  and  oxidize  it  to  sulfate,  thus 
gradually   discharging  both  plates. 


EXPERIMENTAL  CHEMISTRY. 

{Continued  from  page  477) 

bonat  (Na2C03)  by  the  addition  of  more 
coal  in  the  black-ash  fusion;  the  reaction 

being : 

CaCOs       +    C    =    CaO      +  2CO 
Na2C03  +  CaO  +  H20  =  2NaOH  +  CaCOa 

PROPERTIES :— Physical :— 1.  The  phys- 
ical and  chemical  properties  of  Sodium  and 
Potassium  are  quite  similar,  therefore  the 
properties  of  both  will  be  given  under  one 
heading. 


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495 


Both  are  white  solids  of  acrid  and  nau- 
seating taste. 

2.  Both  are  very  caustic,  dissolving  the 
flesh. 

3.  They  are  very  deliquescent  and  sol- 
uble. 

4.  Sodium  hydroxid  imparts  a  flame  of 
yellowish  color,  while  potassium  hydroxid 
imparts  a  purple  color. 

Chemical: — 1.  They  neutralize  acids  and 
form  salts. 

2.  They  are  both  strongly  alkalin. 

3.  They  react  on  many  metals. 

4.  They  absorb  carbon  dioxid  and  form 
carbonats. 

5.  They  react  with  fats  and  oils  to  form 
soaps. 

USES  : — Small  amounts  of  these  hydrox- 
ids  are  used  in  chemical  laboratories,  but 
the  most  important  use  is  that  of  soap- 
making.  Fats  and  oils  are  mainly  stearin 
(or  glyceryl  stearat),  CaHnCGsHasC^a ; 
palmitin .  (or  glyceryl  palmitat),  C3H6 
(CnHsiC^a;  and  olein  or  glyceryl  oleat, 
CsEMGsHmCMs  ;  C3HS  being  the  glyceryl 
radical.  Glycerin  or  (glycerol)  is  GHS- 
(OH),. 

In  saponification  the  hydroxid  of  sodium 
or  potassium  acts  on  the  stearin,  palmitin, 
or  olein,  and  liberates  glycerin,  forming 
sodium  stearat,  etc. 

/  Sodium  I  ,  .  .■  J"  StearaO 
|Hydroxid|+  glyceryl  jPalnutat! 

f  Stearat  "1 
=  sodiums  Palmitat  >  -f-  glycerol 
t  Oleat  J 

The  stearat,  palmitat,  and  oleat  of  sodium 
or  potassium  are  the  chemical  names  for 
soaps.  They  are  soluble  in  water :  hence  a 
solution  of  sodium  chlorid,  in  which  they 
are  insoluble,  is  used  to  precipitat  them. 

It  may  be  of  interest  to  the  reader  to  give 
an  explanation  of  the  action  of  soap.  Soap 
dissolves  in  pure  (or  soft)  water,  and  the 
faintly  alkalin  solution  very  readily  gives 
emulsions  with  the  skin  or  the  fatty  matters 
in  soiled  cloth.  Thus  the  fatty  matter  is 
removed,  and  with  it  is  taken  out  mechanic- 
ally any  dirt  in  other  forms,  such  as  carbon, 
etc.  If  soluble  salts  of  calcium  or  magne- 
sium are  present  in  the  water,  an  insoluble 
stearat,  etc.,  of  these  metals  is  formed  and 
precipitated  as  a  lime  or  magnesium  soap ; 
hence  the  soap  will  not  dissolve  till  these 
salts  are  removed.  The  quantity  of  soap 
necessary  to  make  a  lather  is  the  basis  for 
estimating  the  hardness  of  water.  The 
harder  the  water  the  more  soap  required. 

Therefore  we  may  safely  conclude  that 
the  most  important  use  of  sodium  and 
potassium  hydroxid  is  in  the  manufacture 
of  soap  which  runs  into  thousands  of  tons 
annually. 

They  are  also  used  in  bleacheries,  in  paper 
making,  in  refining  oil,  etc. 

Experiment  No.  98 : 

Pour  10  or  15  cc. 
of  water  into  an  8  ounce  wide  mouth  bottle 
and  have  a  cardboard  or  paper  to  cover  it. 
(Do  not  use  a  glass  plate  as  a  cover),  as  a 
slight  explosion  may  occur  upon  the  dis- 
appearance of  the  metal;  (Fig.  89).  Take 
a  small  piece  of  metallic  sodium  with  a  pair 
of  forceps,  about  the  size  of  a  pea,  and 
drop  it  into  the  bottle  containing  the  water, 
covering  the  latter  immediately  with  a  piece 
of  cardboard  or  paper.  Notice  how  the 
metal  reacts  with  the  water. 

While  the  action  is  going  on,  make  the 
combustion  test,  by  removing  the  cover  and 
quickly  thrusting  a  lighted  splint  into  the 
bottle.    If  there  is  a  flame,  note  the  color. 

It  may  be  that  the  operator  failed  to 
notice   the  phenomena   which   took  place 


when  the  first  piece  of  sodium  was  in- 
troduced ;  in  that  case,  repeat  the  experi- 
ment, using  a  clean  bottle,  and  water. 

Na  +  HaO  =  NaOH  +  H 

Save  the  liquid,  which  is  sodium  hydroxid 
and  evaporate  to  dryness,  and  examine  it 
as  to  color,  causticity  and  solubility. 

Experiment  No.  99: 

Examine  a  piece  of 
freshly  cut  metallic  sodium.  (Do  not  handle 
the  metal  with  your  fingers,  but  use  a  pair 
of  forceps).  Note  its  color,  lustre,  and 
hardness. 

Boil  about  10  cc.  of  water  in  a  test  tube, 
and  pour  it  into  a  clean  bottle,  and  while 
still  hot  drop  a  piece  of  sodium  (a  fresh 
piece)  into  it  and  cover  the  bottle  with  a 
piece  of  cardboard  (not  glass).  Notice  the 
phenomena  carefully. 

When  the  action  stops,  hold  the  lower 
opening  of  a  Bunsen  burner  across  the 
mouth  of  the  bottle,  having  the  cover  re- 
moved as  shown  in  Fig.  90.  Notice  the  yel- 
low color  imparted  to  the  flame,  which  color 
is  characteristic  of  sodium  and  its  com- 
pounds. This  test  must  be  applied  as  soon 
as  the  action  of  the  sodium  stops. 

Experiment  No.  100 : 

Prepare  potassium 
hydroxid,  following  the  steps  exactly  as  in 
the  preceeding  experiment,  except  that 
metallic  potassium  is  employed  in  place  of 
metallic  sodium. 

The  flame,  when  the  Bunsen  burner  is 
placed  across  the  mouth  of  the  bottle,  in 
the  case  of  potassium  will  give  a  purple 
color  instead  of  a  yellowish  color  as  obtain- 
ed with  sodium.  Notice  all  phenomena,  and 
compare  with  that  of  sodium. 

K  +  H20  =  KOH  -)-  H 

Experiment  No.  101 : 
Sodium  Hydroxid  made  from  Slaked  Lime 

and  Sodium  Carbonat. 

Put  about  7  grams  of  finely  crystallin 
sodium  carbonat  (Na2C03)  on  a  piece  of 
paper,  and  on  another  paper  5  grams  of 
slaked  lime  (Ca(OH)2).  Pour  the  two  into 
a  beaker  and  add  about  40  cc.  of  water. 
Pour  the  liquid  obtained  from  the  beaker 
into  a  Florence  flask,  leaving  the  flask  un- 
stoppered;  (Fig.  91).  Place  it  on  a  ring 
stand  or  tripod  on  asbestos,  and  boil  for 
four  or  five  minutes.  Before  completing 
the  boiling  add  water  enough  to  replace 
that  which  evaporates.  Filter,  and  if  the 
solution  is  so  strong  as  to  break  the  filter, 
let  the  mixture  settle,  decant  it,  and  use  the 
decanted  liquid  for  testing. 

Test  the  filtrat  by  its  action  on  solutions 
of  Copper  chlorid,  (CuCU),  Silver  chlorid, 
(AgCU),  and  Ferric  (iron)  Chlorid, 
(FeCl3)  ;  by  its  action  on  red  litmus.  Note 
the  color  effects  in  each  case. 

Experiment  No.  102 : 
Potassium  hydroxid  made  from  slaked  lime 

and  Potassium  Carbonat. 

Prepare  by  similar  method  as  for  sodium 
hydroxid,  except  that  potassium  carbonat 
(K2C03)  is  employed  in  place  of  sodium 
carbonat. 

Compare  all  the  phenomena  observed 
when  potassium  is  used,  with  those  obtained 
by  the  action  of  Sodium  carbonat.  The 
product  obtained  is: 

Ca(OH)a  +  Na2C03  =  CaCOs  +  2  NaOH 
Ca(OH)2  +    K2C03  =  CaCOs  +  2  KOH. 

Experiment  No.  103: 
Electrolytic  Preparation  of  Sodium 
Hydroxid. 

The  apparatus  shown  in  Fig.  92  was  de- 
scribed in  detail  in  the  October  1916  install- 


WhatKindofaManAreYOU? 


STRONGFORT 
The  Perfect  Man 

An  athlete  of  whc 
Saroynt  of  Harvari 
versity  has  said: 

"He  is  wrurueationably  the 

finest  specimen  of  physical 
development  ever  seen." 


Vni- 


YOTJ.  young  or 
old  1  In  your 
teens  or  In  your 
sixties  can  you 
face  life  day  by  day, 
cheerfully,  with  the 
stamina  to  keep  going, 
or  to  rise  to  better 
things?  OR,  are  you 
held  down  witli  the 
consciousness  of  your 
own  physical  and  men- 
tal weakness? 
YOUNG  or  old,  you 
will  be  left  behind, 
among  the  Incompe- 
tents, unless  you  have 
real  HEALTH.  No 
man  ever  succeeded 
without  It. 

YOU  MADE  MIS- 
TAKES— so  has  every 
man.  But  the  Real 
Man  rises  above  his 
mistakes,  makes  the 
lesson  it  gave  him 
serve  him  to  better 
things.  So  can  you. 
You  don't  have  to  go 
through  life.  Weak, 
Run-down,  Nervous, 
Debilitated,  Memory 
Failing,  all  Kinks  and 
Pains. 

YOU  can  be  Strong, 
Vigorous,  Vital,  Man- 
ly I  The  means  are 
here.    Let  me  tell  you 

how. 


YOU  CAN 
COME  BACK! 

I  can  Re-build  you.  Make  you  over  again. 
Re-vitalize  you.  Fill  life  with  the  joyousness 
of  its  purpose.  I,  personally,  am  the  result 
of  the  System  I  have  perfected.  I  live  this 
life,  I  breathe  it,  I  radiate  it  to  all  my  pupils, 
daily  and  they  become  as  1 1  I  can  change 
your  whole  life,  for  the  better.  I  do  not  care 
what  your  physical  ills,  nor  your  mental 
worries,  they  yield  to  the  Power  of  Strong- 
fortism,  embodying  as  it  does  the  true  prin- 
ciples of  Nature's  laws.  No  DRUGS,  OILS, 
PHYSICS,  PILLS  or  other  PIFFLE  I  Just 
Nature,  her  kindly  ways,  under  my  personal 
guidance,  and  you  have  the  safe,  sure,  per- 
fect way  to  HEALTH,  Strength,  Physical 
Power,  the  VIGOR  that  makes  every  breath 
Eestacy!  i  CAN  SAVE  YOU  _ 
IP  YOU  ABB  INTERESTED  ENOUGH  IN  YOUR- 
SELF to  ask  me  a  few  questions.  It  won't  cost 
you  anything.  It  will  not  put  you  under  any  obli- 
gations. Just  because  you  fell,  because  you  made 
that  mistake,  don't  let  it  drag  you  down.  Don't 
let  it  be  a  millstone  about  your  neck.  Tell  me  In 
confidence  of  your  physical  troubles,  no  matter 
what  they  are  and  I  can  advise  you  and  help 
you  wonderfully.    Yes,  I  will  give  you 

ADVICE  FREE 
If  you  knew  the  work — the  wonderful  good  that  I 
have  been  doing  for  so  many  years  you  would  not 
wonder  why  I  appeal  so  strongly  to  EVERY  MAN 
to  come  to  me  and  let  me  help  him. 

LET  ME  RE-BUILD  YOU 
My  way  is  exclusively  my  own,  and  I  SUCCEED 
because  I  realize  that  every  person  is  different,  and 
each  pupil  must  have  individual,  personal  atten- 
tion. That  too,  is  why  each  of  my  pupils  succeeds. 
I  never  had  a  failure.  It  is  the  SYSTEM — it  Is 
STRONGFORTISM,  let  me  tell  you  what  it  will 
mean  to  you. 

There  is  a  liberal  education  in  my  book.  IN- 
TELLIGENCE IN  PHYSICAL  AND  HEALTH 
CULTURE,"  free  for  three  2-cent  postage  stamps 
to  cover  cost  of  mailing. 

LIONEL  STRONGFORT 

MASTER  OF  PHYSICAL  CULTURE 

309  PARK  BLDG.,  NEWARK,  N.  J. 

Personal  consultation  by  special  appointment  only, 

 FREE  CONSULTATION  COUPON  

Dear  Strongfort: — Please  send  me  your  book 
"INTELLIGENCE  IN  PHYSICAL  AND  HEALTH 
CULTURE,"  for  postage  of  which  I  enclose  6  cents 
In  stamps. 

I  have  marked  (X)  before  the  subject  In  which 
I  am  interested  and  should  like  you  to  send  me  a 
personal  talk  on  this  subject. 


.  .Thinness 
.  .Obesity 
.  .Nervousness 
. .  Insomnia 
.  .Indigestion 
.  .Constipation 
.  .Short  Wind 
.  .Flat  Chest 
.  .Colds 
. .  Catarrh 
.  .Poor  Circulation 
. .  Rheumatism 
. .  Heartweakness 
. . Headache 
.  .Skin  Disorders 
.  .Lung  Trouble 

Name   


.  Round  Shoulden 

.Stoop  Shoulders 

.  Deformity         No.  309 

.  Rupture 

.Youthful  Errors 

.Devitalizing  Losses 

.  Impotency 

.  Despondency 

.Poor  Memory 

.Flat  Feet 

.Increased  Height 

.Muscular  Development 

.Great  Strength 

.Weight  Lifting 

.Advanced  Course 

.  Many- Weight  Barbell 


Street   

City   State 


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ment  of  this  series  of  papers  (page  405), 
and  reference  is  made  for  a  detailed  de- 
scription of  this  apparatus.  Essentially,  it 
consists  of  a  U-tube,  fitted  with  two  two- 
holed  rubber  stoppers,  thru  which  pass  the 
delivery  tubes,  and  two  electrodes,  sealed 
in  a  piece  of  glass  tubing  which  contain 
mercury.  The  electrodes  should  be  of 
platinum,  as  this  substance  expands  and 
contracts  in  the  same  proportion  as  glass, 
besides  being  a  better  electrode  than  other 
substances,  it  withstands  the  action  of  the 
various  solutions  much  better  than  copper, 
nickel,  or  other  electrodes  will. 

This  apparatus  may  be  considered  a 
laboratory  modification  of  the  Castner-Kell- 
ner  method  of  electrolytic  apparatus  shown 
in  Fig.  88.  The  U-tube  is  filled  with  mer- 
cury so  that  it  extends  above  the  bends  of 
both  sides  of  the  tube,  which  prevents  the 
chlorin  liberated  from  the  anode  from  com- 
ing in  contact  with  the  sodium  hydroxid 
formed  at  the  cathode.  If  a  little  red  litmus 
is  added  to  the  salt  solution,  it  will  be 
bleached  by  the  chlorin  around  the  anode, 
and  turned  blue  by  the  sodium  hydroxid 
at  the  cathode.  Chlorin  is  liberated  at  the 
anode,  and  we  may  assume  that  sodium  is 
separated  for  an  instant  at  the  cathode, 
which  at  once  interacts  with  the  water 
present,  liberating  hydrogen  and  forming 
sodium  hydroxid. 

The  equation  of  the  reaction  caused  by 
the  electrolysis  of  the  sodium  chlorid  solu- 
tion (common  table  salt)  may  be  represent- 
ed by  the  following  equation  : 

NaCl  +  2H..O  =  NaOH  +  H  +  CI 

AQUA  REGIA. 

History  ; — 

This  name  is  given  to  a  mixture  of  Nitric 
and  Hydrochloric  acids  which  is  frequently 
employed  for  dissolving  gold  and  platinum, 
as  well  as  many  metallic  ores  and  other 
substances. 

The  Alchemists  called  this  mixture  Aqua 
Regia,  which  meant  Royal  Water  or  King 
of  Waters,  because  it  possest  the  power 
of  dissolving  Gold,  which  was  considered 
the  king  of  metals.  Aqua  Regia  was  there- 
fore believed  to  be  the  strongest  solvent 
known.  Any  thin  liquid  they  termed  Aqua, 
the  Latin,  meaning  water,  and  affixing  some 
adjective  to  express  the  kind  of  water,  as 
Aqua  Pura  (Pure  Water),  Aqua  Fortis 
( Strong  Water,  which  they  applied  to  Nitric 
acid),  etc. 

Strictly  speaking,  Aqua  Regia  is  not  an 
acid,  tho  it  is  often  so  called  from  its 
constituents,  nitro-hydrochloric  acid.  It  is 
made  by  mixing  the  two  acids,  Nitric  and 
Hydrochloric, — one  volume  of  the  former  to 
three  volumes  of  the  latter.  A  reaction 
takes  place  which  is  variable,  depending  on 
the  relative  amounts  and  strengths  of  the 
two  acids.    A  general  reaction  is : — 


3  HCl  +  HN03 


2  H20  +  NOC1  +  CI, 
Nitrosyl 
Chlorid 


The  solvent  power  of  the  Aqua  Regia 
depends  upon  the  fact  that,  on  heating,  this 
mixture  of  acids  evolves  Chlorin.  In  the 
reaction  chlorin  is  always  liberated.  When 
Aqua  Regia  is  employed  to  dissolve  metals, 
the  chlorin  liberated,  during  the  reaction 
forms  chlorids,  the  higher  chlorid  in  case 
the  metal  has  more  than  one  valence.  The 
action  is  very  vigorous,  especially  if  the 
liquid  is  hot.  While  Gold  (Au)  and 
Platinum  (Pt)  are  not  affected  by  hydro- 
chloric acid  or  Nitric  acid,  they  combine 
readily  with  the  chlorin  to  form  gold  chlorid 
(AuCl3)  and  platinum  chlorid  (PtCU), 
which  dissolve  in  the  liquid. 

As  chlorin  is  one  of  the  strongest  of  oxid- 
izing agents,  either  as  a  gas  or  in  solution, 
aqua  regia  will  change — ous  to — ic  salts ;  as, 
for  example,  Mercurous  chlorid  (HgCl)  to 


Mercuric  chlorid  (HgCl2),  Ferrous  chlorid 
(Iron)  chlorid  (FeCl2)  to  Ferric  (Iron) 
Chlorid  (FeCU),  etc.  It  possesses  a  strong, 
irritating,  characteristic  odor,  the  color 
varying  from  orange  to  red.  Owing  to  the 
escape  of  its  gases  it  cannot  be  kept,  but 
should  be  made  as  required  for  use. 
Experiment  No.  104. 

Hold  a  test  tube  in  the  left  hand,  nearly 
on  a  level  with  the  eye,  and  pour  into  it 
about  6  cc.  of  hydrochloric  acid  (HCl),. 
(Fig.  8b  in  the  August,  1916,  "Electrical 
Experimenter").  Add  to  this  about  2  cc. 
of  nitric  acid. 

Watch  the  mixture  a  moment,  and  if  no 
action  can  be  noticed,  bring  the  tube  to  a 
flame  for  a  moment  only. 

3HC1  +  HNG-3  =  2H20  +NOC1  +  Cl2 
Nitrosyl 
Chlorid 

The  products  are  for  the  most  part, 
chlorin  (CI),  Nitrosyl  chlorid  (NOC1), 
and  Water  (H20).  The  mixture  is  called 
aqua  regia,  or  nitro-hydrochloric  acid,  its 
strength  being  mainly  due  to  chlorin. 
Experiment  No.  105. 

Put  one  or  two  pieces  of  Zinc  into  a 
tube  and  add  a  little  of  the  aqua  regia.  If 
any  gas  escapes  test  its  combustibility  by 
applying  a  lighted  splint,  also  smell  the 
odor,  etc. 

Put  into  a  dish  a  few  pieces  of  copper 
and  add  a  very  little  aqua  regia.  After  a 
minute  dip  a  splint  into  the  solution ;  then 
hold  it  in  the  flame  of  a  Bunsen  burner  and 
notice  any  color  effects. 

Moisten  a  glass  rod  and  roll  upon  one 
end  of  it  a  half  sheet  of  gold  leaf.  Dip 
this  into  a  tube  containing  a  small  amount 
of  aqua  regia,  using  care  not  to  touch  the 
sides  of  the  tube.  Notice  the  action  the 
instant  the  gold  touches  the  liquid. 

Experiment  No.  106. 

Ascertain  whether  gold  will  dissolve  in 
either  hydrochloric  or  nitric  acid,  sep- 
arately, using  a  clean  tube  and  glass  rod, 
and  heating  each  liquid  to  the  boiling  point. 
(Great  care  should  be  exercised  in  bring- 
ing these  acids  to  the  boiling  point,  being 
careful  that  the  acid  does  not  boil  over  or 
spatter  on  the  hands  or  clothes.  If  the 
action  becomes  too  violent  immediately  re- 
move the  tube  from  the  flame.) 

If  it  does  not  dissolve,  pour  the  contents 
of  each  tube  together,  and  notice  any  action 
which  takes  place. 

Experiment  No.  107. 

Ascertain  the  action  of  aqua  regia  on 
scraps  of  iron,  and  note  whether  the 
product  is  the  same  as  when  hydrochloric 
acid  acts  on  iron.  Test  the  result  of  each 
action  by  the  use  of  ammonium  hydroxid 
(NH4OH),  also  a  splint  applied  to  the 
mouth  of  the  tube,  to  determine  if  a  gas  is 
present,  etc. 

When  nitric  acid  acts  as  an  oxidizing 
agent,  it  usually  decomposes,  as  represented 
in  the  following  equation : 

2HNO3  =  H20  +  2NO  +  30 

If  hydrochloric  acid  is  present,  the  oxy- 
gen, as  fast  as  formed,  reacts  with  the  acid 
according  to  the  following  equation : 
6HC1  +  30  =  3H.0    +  3C12 

The  nitric  oxid  formed  according  to  the 
first  equation  is  not  evolved  as  such,  but 
combines  with  the  chlorin  liberated  accord- 
ing to  the  second  equation,  to  form  an 
orange-yellow,  gaseous  compound  known  as 
Nitrosyl  chlorid  (NOC1). 

2NO  +  Cl2  =  2NOC1 

By  combining  these  three  equations  in 
the  regular  way  and  dividing  the  resulting 
equation  by  2,  in  order  to  get  its  simplest 
form,  one  obtains  the  following: 
HNO;  +  3HC1  ==  2H20  +  NOC1  +  Cls 
Nitrosyl 
Chlorid 


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THE  ELECTRICAL  EXPERIMENTER 


499 


HISTORIC  ELECTRIC 
APPARATUS. 

(Continued  from  page  448) 

the  year  1810.  He  did  not  enclose  his  in- 
candescent lamp  in  a  vacuum  or  in  a  tube 
however,  but  contented  himself  with  bring- 
ing a  strip  of  platinum  1/30  of  an  inch 
thick  by  18  inches  in  length  to  a  high  state 
of  brilliance  by  connecting  it  to  a  large 
number  .of  batteries.  Little  was  done  in 
succeeding  years  to  evolve  any  form  of 
incandescent  electric  lamp,  and  the  next  we 
hear  of  this  now  universal  illuminant  is  in 
1841,  when  we  find  the  work  of  de  Moleyns. 
His  incandescent  lamp  utilized  a  fine  plati- 
num wire.  About  the  first  incandescent 
lamp  of  the  exhausted  bulb  type  that  we 
find  a  record  of,  is  that  due  to  Starr,  a 
Yankee  inventor  of  Cincinnati,  Ohio.  His 
first  product  bears  the  date  of  1845,  when 
he  took  out  a  patent  for  a  carbon  filament 
lamp  with  an  exhausted  bulb.  He  took  out 
many  patents,  and  evolved  a  diversified 
number  of  incandescent  lamps  and  fila- 
ments, but  owing  to  the  lack  of  commercial 
dynamos,  success  in  those  days  was  of  short 
duration. 

Another  earnest  worker  in  this  field  was 
Henrich  Gobel,  of  New  York  City,  who 
produced  a  very  promising  carbon  filament 
lamp  in  1854.  Gobel  first  used  wood  char- 
coal for  the  filament,  and  later  tried  carbon- 
ized bamboo. 

The  Edison  incandescent  lamp  upon 
which  large  sums  of  money  were  spent  in 
development  for  several  years,  finally 
emerged  from  the  laboratory  in  1879,  and 
from  that  date  progress  was  real  and  as- 
sured in  the  development  of  electric  light- 
ing. The  illustration  in  Fig.  7  shows  the 
earliest  form  of  incandescent  lamp,  and  also 
the  Edison  lamp  as  first  manufactured.  The 
Edison  lamp  had  an  exhausted  bulb,  and  a 
carbon  filament  was  used  composed  of  car- 
bonized brown  paper  at  first,  but  shortly 
afterward  this  was  made  of  carbonized 
bamboo.  Thousands  of  different  kinds  of 
filament  and  materials  for  them  were  ex- 
haustively tested  out  in  Edison's  laboratory, 
and  it  is  surprising  to  learn  that  even  in 
those  days  there  were  a  number  of  inven- 
tors who  proposed  metallic  filament  lamps, 
and  actually  tried  out  incandescent  lamps, 
having  filaments  coated  with  metallic  oxids, 
etc. 

The  arc  lamp,  which  is  very  common 
now-a-days,  was  invented  by  Sir  Hum- 
phrey Davy,  who  discovered  in  1801,  that 
by  connecting  up  a  large  number  of  battery 
cells  to  a  pair  of  pointed  carbon  rods,  that 
when  these  rods  were  placed  in  contact  and 
then  separated,  an  electric  arc  of  great  bril- 
liance tended  to  form  between  the  carbons. 
In  1809,  Davy  exhibited  publicly  the  first 
electric  arc  light,  which  was  excited  by  two 
thousand  primary  battery  cells.  Arc  lights 
languished  for  a  good  many  years  until  an 
Englishman  by  the  name  of  Wright,  in  1844, 
devised  the  first  successful  automatic  self- 
feeding  arc  lamp.  Wright's  ingenious  au- 
tomatic arc  lamp  is  shown  in  Fig.  8,  as 
also  Davy's  first  arc  lamp  of  the  hand-feed 
type. 

Wright's  arc  lamp  comprised  a  series  of 
carbon  discs  with  bevelled  edges,  arranged 
in  the  manner  illustrated.  Two  of  these 
discs  were  movable;  thus  making  it  pos- 
sible to  compensate  for  the  change  in  the 
length  of  the  arc  as  the  discs  were  burnt 
away,  and  all  of  the  carbon  discs  were  ro- 
tated while  the  lamp  was  in  operation  by 
means  of  clock-work  mechanism. 

The  telephone,  now  in  use  in  practically 
every  city  and  community  all  over  the  civil- 
ized world,  first  saw  the  light  of  day  in 
Germany  (1861)  in  the  apparatus  invented 
by  Phihp  Reis,  instructor  in  natural  sciences 
at  Professor  Garnier's  Institute,  a  select 


school  for  boys  at  Friedrichsdorf,  near 
Homburg.  As  Professor  Sylvanus  P. 
Thompson  has  declared — "the  apparatus 
devised  by  Reis  was  the  employment  of  a 
loose  or  imperfect  contact  between  two 
parts  of  a  conducting  circuit  so  that  the 
pressure  and  electrical  resistance  might  be 
varied  by  differing  stress."  By  this  system 
(see  Fig.  9)  Reis  was  able  to  transmit  musi- 
cal sounds,  especially  whistling  and  other 
shrill  tones,  with  all  variations  of  pitch  and 
loudness,  altho  without  timbre,  probably  re- 
sembling somewhat  the  sound  of  a  xylo- 
phone (wooden  piano) — and  less  perfectly, 
also,  the  sounds  of  the  human  voice;  the 
consonants  being  readily  represented,  but 
the  vowels  less  distinctly,  if  at  all. 

Referring  to  this  early  forerunner  of  the 
wonderful  telephone  which  Professor  Bell 
(1876)  later  perfected  so  as  to  be  able  to 
transmit  articulate  speech  over  any  distance 
by  electrical  means,  we  find  that  Reis  used 
as  a  transmitter,  a  small  box  having  two 
openings,  one  at  the  side  for  the  mouth- 
piece, and  the  other  at  the  top,  closed  by  a 
diafram,  made  from  the  smaller  intestine 
of  a  pig.  At  the  center  of  this  membrane 
was  cemented  a  strip  of  platinum  in  loose 
contact  with  the  point  of  a  platinum  wire 
held  in  position  above  it  by  a  light  leaf 
spring.  The  receiver  of  the  Reis  system 
comprised  a  steel  wire,  wrapt  around  with  a 
coil  of  insulated  wire,  thus  forming  an 
electro-magnet.  This  was  mounted  on  a 
small  resonant  wooden  box  resembling  a 
violin,  and  which  served  as  a  sounding 
board.  To  this  was  later  added  a  cover  of 
thin  wood,  against  which  the  ear  could  be 
prest  to  receive  the  sounds  transferred 
along  the  wire  electrically  from  the  trans- 
mitter. 

Wireless  telegraphy  for  practical  pur- 
poses really  dates  back  to  the  brilliant  scien- 
tific researches  of  Henrich  Hertz.  Many 
electrical  writers  date  wireless  telegraphy 
back  to  the  first  wireless  transmission  of 
messages  to  1838  when  Professor  Joseph 
Henry,  of  Princeton  University,  succeeded 
in  setting  up  induced  currents  in  the  cellar 
of  a  building,  when  a  Leyden  jar  was 
charged  and  discharged  by  means  of  a 
static  electrical  machine  placed  in  the  top 
room  of  his  residence.  Next  in  line  to  be 
credited  by  many  writers  is  Professor  S.  F. 
B.  Morse,  who  is  stated  by  one  authority 
("Wireless  Telegraphy,"  by  Sewall,  1904) 
to  have  actually  sent  the  first  signal  with- 
out wires  on  December  16th,  1842,  when  he 
succeeded  in  sending  a  wireless  telegram 
across  a  canal  80  feet  in  width,  and  in  No- 
vember, 1844,  Mr.  A.  D.  Gale,  under  the 
instruction  of  Professor  Morse,  transmitted 
wireless  signals  across  the  Susquehanna 
River  at  Havre  de  Grace,  a  distance  of 
nearly  one  mile. 

This  wireless  scheme,  however,  was  based 
on  the  principle  of  conduction,  and  thus  was 
limited  in  its  application  and  in  the  range 
that  could  be  covered.  Considerable  ex- 
periment was  done  with  inductive  systems 
of  wireless  telegraphy  and  telephony,  in 
America,  from  1882  to  1885  by  Professor 
Dolbear  and  Thomas  A.  Edison,  the  latter 
investigator  having  successfully  signaled 
thru  space  to  a  moving  train  from  a  wire 
installed  on  poles  beside  the  railway,  in 
1885. 

The  crowning  achievement  in  the  realm 
of  radio-telegraphy  by  etheric  wave  trans- 
mission was  that  of  Hertz,  in  1886.  Across 
a  small  spark  gap  in  a  ring  of  wire  sus- 
pended in  a  room  (there  having  been  no 
electrical  contact  with  the  charging  appa- 
ratus), Hertz  caused  tiny  sparks  to  appear 
as  the  result  of  the  passage  across  another 
and  longer  spark  gap  of  the  oscillatory 
discharge  from  a  Leyden  jar.  Finally  we 
come  to  the  work  of  Guglielmo  Marconi, 


TYPEWRITER  SENSATION 

FREE  TRIAL  Use  as  You  Pay.  Only 
$2.50  a  month  until  the  low  total  price  of 
$48.80  is  paid  and  the  machine  is  yours. 


FREE 
TRIAL 


This  is  absolutely  the  most  generous 
typewriter  offer  ever  made.  Do  not  rent  a 
machine  when  you  can  pay  $2.50  a  month 
and  own  one.  Think  of  it — Buying  a 
$100.00  machine  for  $48.80.  Cash  price, 
$45.45.  Never  before  has  anything  like 
this  been  attempted. 

Visible     L  •    C  •  S  III  1 1  ll 

Perfect  machines,  Standard  size, 
Keyboard  of  Standard  Universal  arrange- 
ment writing  84  characters — universally  used  In 
teaching  the  touch  system.  The  entire  line  of 
writing  completely  visible  at  all  times,  has  the 
tabulator,  the  two  color  ribbon,  with  automatic 
reverse,  the  back  spacer,  ball  bearing  type  bars, 
ball  bearing  carriage  action,  ball  bearing  shift 
action,  in  fact  every  late  style  feature  and  modern 
operating  convenience.  Comes  to  you  with  every- 
thing complete;  tools,  cover,  operating  book  and 
Instructions,  ribbon,  practice  paper — nothing  ex- 
tra to  buy.  You  cannot  imagine  the  perfection  of 
this  beautiful  reconstructed  typewriter  until  you 
have  seen  it.  1  have  sold  several  thousand  of 
these  perfect  latest  style  Model  No.  2  machines 
at  this  bargain  price  and  every  one  of  these 
thousands  of  satisfied  customers  had  this  beau- 
tiful, strictly  up  to  date  machine  on  Ave  days' 
free  trial  before  deciding  to  buy  it.  I  will  send 
It  to  you  F.  O.  B.  Chicago  for  Ave  days'  free 
trial.  It  will  sell  itself,  but  if  you  are  not  sat- 
isfied that  this  is  the  greatest  typewriter  you  ever 
saw,  you  can  return  it  at  my  expense.  You 
won't  want  to  return  it  after  you  try  it — you 
cannot  equal  this  wonderful  value  anywhere. 

You  Take  No  Risk — Put  in  Your  Order  Now 

When  the  typewriter  arrives  deposit  with  the  ex- 
press agent  $8.80  and  take  the  machine  for  five 
days'  trial.  If  you  are  convinced  that  it  is  the 
best  typewriter  you  ever  saw,  keep  it  and  send 
me  $2.50  a  month  until  our  bargain  price  of 
$48.80  is  paid.  If  you  don't  want  it,  return  It 
to  the  express  agent,  receive  your  $8.80  and  re- 
turn the  machine  to  me.  I  will  pay  the  return 
express  charges.  This  machine  is  guaranteed  Just 
as  if  you  paid  $100.00  for  it.  It  is  standard. 
Over  one  hundred  thousand  people  own  and  use 
these  typewriters  and  think  them  the  best  ever 
manufactured.  The  supply  at  this  price  Is  very 
limited,  the  price  will  probably  be  raised  when 
my  next  advertisement  appears,  so  don't  delay. 
Fill  In  the  coupon  today — mall  to  me— the  type- 
writer will  be  shipped  promptly.  There  Is  no 
red  tape.  I  employ  no  solicitors — no  collectors — 
no  chattel  mortgage.  It  is  simply  understood  that 
I  retain  tiUe  to  the  machine  until  the  full  $48.80 
Is  paid.  You  cannot  lose.  It  is  the  greatest  type- 
writer opportunity  you  will  ever  have.  Do  sot 
send  me  one  cent.  Get  the  coupon  In  the  malls 
today — sure. 

Harry  A.  Smith.  738,  231  N.  Fifth  A  v..  Chleago 


H.  A.  Smith,  738  .  231  N.  Fifth  Ave.,  Chicago,  III. 

Ship  me  a  No.  2  L.  C.  Smith  F.  O.  B.  Chicago, 
as  described  in  this  advertisement.  I  will  pay  you 
the  $40.00  balance  of  the  SPECIAL  $48.80  purchase 
price  at  the  rate  of  $2.50  per  month.  The  title  to 
remain  in  you  until  fully  paid  for.  It  is  understood 
that  I  have  five  days  in  which  to  examine  and  try 
the  typewriter.  If  I  choose  not  to  keep  it  I  will 
carefully  repack  it  and  return  it  to  the  express  agent 
It  is  understood  that  you  give  the  standard  guarantee 
for  one  year. 

NAME   

ADDRESS   


GENERATORS!  ALTERNATORS! 

We  have  a  complete  line  of  sturdy,  efficient  gen- 
erators and  alternators  from  100  to  1000  watts. 
We  furnish  complete  parts  for  these  finished 
ready  to  assemble  with  instructions  to  wind. 
Transformers  made  to  order.  Send  for  catalogue. 

ALL  AT  FACTORY  PRICES 
Bergmann  Motor  Works,  442-446  Niagara  St.,  Buffalo, N.T 


Driver  Agents  Wanted 


Drive  and  demonstrate  the  Bush  Car.  Pay  for  it  out  of 
your  commiasiODS  on  Bales.  My  agentsaremaking  money.  Ship- 
J  mentsare  prompt. 

Five-Pass. ,34. 7  H.P.*  »  82x354  tires  Bush  Cars  guar- 
anteed or  money 
bach.  1918  models 
ready. 

Write  at  once  for 
my  48-page  cata- 
log and  all  partic- 
ulars. Address  J. 
H.  Bush,  Fran. 
Dept.  114] 


InWheelbase 
Delco  Ignition— Elect.  Stg.  &  Ltg 
BUSI1  OIOTOB  COJIFAHY,  Bush  Temple,  Chicago,  Illinois 


You  benefit  by  mentioning  "The  Electrical  Experimenter"  when  writing  to  -"ivertisers. 


500 


THE  ELECTRICAL  EXPERIMENTER 


November,  1917 


!//andWATCHES  © 
OPT  CREDIT  I' 


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TERMS  LOW  AS  $1.50  PER  MONTH 

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This  Is  an  extraordinary  saving. 

SPECIAL  $39.50 
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A  wonderful  value,  $4.50  par  month. 


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Any  watch  yon  want  on  easy  payments.  Be 
sure  to  send  for  our  112  page  catalogue.  Over  2000 
suggestions.  Watches,  Jewelry.  Diamonds.  This 
book  describes  our  big  bargains  in  all  lines. 

All  sold  on  Easy  Payments  and  Free  Trial. 

Send  for  it  this  minute.  A  postal  will  bring  it. 
ALFRED  WARE  COMPANY,  Dept.  795     St.  Louis,  Mo. 


Big  Free  Catalog 


Interested 
in  Science? 


You  will  find  all  of  the  lateat  and  S 
famous  wonders  and  stunts  fully  lllus  SS 
trated    in    Edrhnan's    256    pp.    boob  S 
"EXPERIMENTS."    $1.50    Ppd.      A  SS 
wealth  of  information  that  you  wanl  3 
and   cannot   find    elsewhere,    such    as  S 
"Ultra  -  violet    Bays,"    "High    Fre-  S 
queney."  "Mechanics."  "Wireless  E*  " 
ploded  Mines."  and  "Are  Welding"- 
also  "How  to  Establish  Your  Labora- 
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Now  is   the  golden  time  to  get  a 
copy  of  Edelman'a  2  72  pp.  book  "EXPERI  3 
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You  do  not  need  a  set  in  operation  because  SS 
this  plain  English  book  shows  you  all  about  S 
tuning,  wavelengths,  resonance,   audion  oscillators  £ 
^.etc.  so  you  understand.    All  modern  equipment  Is  ^ 
S  "  ren  together  with  new  material  on  wireless  tele- 

phony,  amplifiers,  experiments  requiring  no  aerial  S 
g  and  a  list  of  IT  S.  Radio  Patents,  $1.50  Ppd  g 
Experimenter's  Library  onlyi  $2.85  S 
Both  of  above  boot's  handsomely  bound  in  Gold-% 
Stamped  covers,  f.2o  patfes,  furrnei  Iv  f>n  this  & 
month  only  $2>5  l'pd.  i,,l,  h„<„,  books  are  aba" S 
lutely  c-uaranteed.  You  are  sure  to  be  satisfied.  ^ 
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Lifts  about  3  pounds.  Educa- 
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to  perform  endless  tests,  experi- 
ments and  make  other  magnets. 
Nothing  better  made.  Sent  par- 
cel post  $1.00  each. 

Electric  Generators 

We  have  a  number  of  Fine 
Hand  Generators  which  we  will 
dispose  of  at  bargain  prices. 
Give  up  to  about  100  volts, 
alternating  current.  You  can 
make  direct  if  desired.  Strict- 
ly high  grade.  While  they  last, 
$3.00  each. 

Watson   Electric  Co. 

123  S.  Michigan  Ave.,  Chicago 


AUTOMATIC  REPEATING  RIFLE 

KIRES  20  SHOTS  IN   ONE  LOADING. 
Same  size  anil  stiape  as  resrular  automatic 
revolver.    Shoots  B.  B.  shots  obti 
anywhere,  same  as  other  ri 
No  caps  or  load  necessary,  as  it  workB  witti 
a  spring  and  shoots  with  rapidity  and  ac- 
curacy.   Nothing  to  explode.  Absolutely 
harmless  and  safe.  Well  made  and  finished- 
Sent  by  mail  complete  with  round  of  shot  for  ONLY  26c. 
postpaid. 


Dept.  921 


whose  successful  publisht  experiments  date 
from  1896,  when  he  succeeded  in  trans- 
mitting wireless  signals  by  means  of 
Hertzian  waves  in  the  ether  across  a  space 
of  100  yards  at  the  British  Postoffice  in 
London.  Soon  afterwards  he  made  a  suc- 
cessful trial  of  sending  and  receiving  wire- 
less signals  over  a  distance  of  two  miles 
on  Salisbury  Plain,  and  from  then  on,  the 
art  of  radio  signaling  advanced  by  leaps 
and  bounds,  and  it  was  but  a  few  years,  or 
to  be  exact  on  Thursday,  Dec.  12,  1901, 
at  12.30  P.  M.,  when  Marconi  received  the 
first  wireless  signal  across  the  Atlantic 
Ocean  (over  2,000  miles)  between  Poldhu, 
England,  and  Cape  Cod,  Mass.— this  im- 
mortal radio  signal  having  been  the  letter 
"S"  as  represented  telegraphically  by  three 
dots. 


RADIO  ROLL 

{Continued  fro 

Utah 

Clifton  Guiver 
Cedric  E.  Hart 

Virginia 

Jno.  P.  Kyde 
W.  K.  Smith,  Jr. 
Lisle  E.  Roadhouse 
S.  C.  Haight 
Adolph  Lefkowitch 
J.  J.  Campbell 

Vermont 

A.  M.  Dole 

Washington 

L.  R.  Devine 
Geo.  Stinley 
Chas.  Callahan 
R.  Thelberg 
E.  V.  Olson 


OF  HONOR. 

m  page  462) 

West  Virginia 

Chas.  P.  Guice 
Harry  Cunningham 
Hugh  N.  Montgomery 
E.  B.  Dadisman 

Wisconsin 

E.  Smith 
Norman  Kuzweg 
Robert  Brannfeld 
Neil  Werner 
Wm.  C.  White 
Weldon  Eisenbraml 
Harry  Gerky 
Wm.  O.  Block 
Lester  Westfahl 
Robert  Donaldson 

Wyoming 

Gaylord  S.  Clark 
T.  C.  Harker 


AN   EXCEPTIONAL  EXPERIMENTAL 
LABORATORY. 

{Continued  from  page  479) 

various  rare  elements  and  compounds, 
microscopes,  electric  furnaces,  electric 
ovens,  thermostats  for  controlling  the 
temperature  of  the  room  in  cold  weather, 
etc.  In  short  we  have  facilities  for  con- 
ducting all  chemical,  electro-chemical, 
metallurgical  and  general  testing  and  re- 
search work. 

By  the  aid  of  a  Photo-micro-graphic  at- 
tachment of  our  own  design  and  with  an 
ordinary  plate  camera,  excellent  photos  of 
the  various  chemical  phenomena  are  obtain- 
ed. As  our  dark  room  is  right  beside  the 
testing  tables  we  can  at  once  develop  and 
finish  any  photographs  and  see  if  the  result 
is  satisfactory.  This  is  an  extreme  ad- 
vantage, in  that,  if  the  results  are  poor  we 
can  retake  the  picture  at  once,  thereby 
eliminating  all  chances  of  failures  in  our 
photographic  tabulation  of  results. 

The  dark-room  is  located  in  one  of  the 
small  rooms,  which  has  no  windows,  right 
beside  our  chemical  and  testing  tables.  A 
shelf  is  set  up  on  one  side  of  this  room, 
upon  which  only  photographic  operations, 
such  as  developing,  fixing,  printing,  etc.,  are 
done.  On  the  other  side  of  this  room  is  a 
large  shelf  upon  which  we  have  permanent- 
ly constructed  our  enlarging  and  copying 
camera.  At  the  other  end  of  the  room 
are  the  trays,  wash  boxes,  fixing  boxes,  and 
printing  frames.  The  fourth  wall  contains 
the  necessary  chemical  reagents  and  prep- 
arations. 


JOHNSON  SMITH  &  CO.. 

54  W.  Lake  St„  Chicago  ' 


RADIO  ROLL  OF  HONOR 

Application  for  Membership  in  the 
Radio  League  of  America 

3 THE  UNDERSIGNED,  a  Radio  Amateur,  am  the  owner  of  a  Wireless 
Station  described  in  full  in  this  application.    My  station  has  been  in  use 
t  since  ,  and  I  herewith  desire  to 

apply  for  membership  in  the  RADIO  LEAGUE  OF  AMERICA.  I  will  abide 
by  all  the  rules  of  the  LEAGUE,  and  I  particularly  pledge  my  services  as  a 
Radio  operator,  or  for  Signal  Corps  duty  to  the  United  States  Government 
when  called  upon. 

I  understand  that  this  blank  with  my  signature  will  be  sent  to  the  United 
States  Government  officials  at  Washington,  who  will  make  a  record  of  my  name. 


Witnesses  to  signature : 


Name  

City.. . 
State. 


Date . 


.191 


Description  of  My  Station  and  Apparatus 


Sending 
Receiving 


I  can  send  approximately  words  per  minute. 

I  can  receive  approximately  words  per  minute. 

My  age  is  years. 


(11-17) 


You  benefit  by  mentioning  "The  Electrical  Experimenter"  when  writing  to  advertisers. 


November,  1917 


THE   ELECTRICAL  EXPERIMENTER 


501 


THE  WORLD  AFTER  THE  WAR. 

By  a  Teuton  Scientist. 
What  will  the  world  be  like  after  the 
war?  A  German  scientist's  imaginative 
after-war  picture  is  the  feature  of  the  latest 
number  of  the  German  review,  Zukunft. 
The  author,  Professor  Moritz  Lesser,  is 
a  member  of  the  faculty  of  engineering 
of  the  University  .of  Bonn.  The  profes- 
sor pictures,  in  fanciful  style,  a  world  at 
peace,  in  friendly  and  international  rela- 
tionship making  use  of  the  technical  dis- 
coveries which  have  been  made  during  the 
war  for  the  development  of  commercial 
enterprise.  The  article  in  part  is  as  fol- 
lows : 

"Three  months  after  the  end  of  the  war, 
the  directors  of  the  leading  banks  and  cor- 
porations of  Germany  held  a  meeting  to 
the  number  of  3,000  in  the  Reichstag,  with 
the  home  secretary  for  chairman,  and 
founded  a  company  'For  the  Development 
and  Use  of  Inventions  Discovered  During 
the  War.'  The  object  of  the  company  was 
to  employ  in  peace  the  technical  progress 
which  had  been  accomplished  under  the 
stress  of  war,  and  the  capital  subscribed 
was  40  times  as  great  as  required. 

"One  object  of  the  company  was  to 
build  submarines  for  pleasure  trips  and 
to  search  for  treasures  lost  during  the  war. 

"It  was  found  possible  to  build  a  sub- 
marine which  sank  to  a  depth  of  more  than 
a  mile,  and  from  this  sprang  the  inter- 
national company  for  raising  the  ships 
sunk  during  the  war.  The  work  was  an 
immense  success,  and  large  sums  of 
money  were  made  from  this  salvage  work. 
There  was  also  huge  profit  in  taking 
passengers  in  these  ships  for  trips  of  ex- 
ploration and  sightseeing  along  the  bot- 
tom of  the  sea.  Ships  were  found  which 
had  gone  down  centuries  ago,  and  one 
expedition  recovered  the  treasure  of  a 
whole  continent  which  was  sunk  in  a 
Spanish  Armada.  Moreover,  rich  veins  of 
coal  and  iron  and  other  minerals  were  dis- 
covered in  the  sea. 

"Meanwhile  wireless  telegraphy  was  per- 
fected until  it  was  possible  to  send  a  cur- 
rent around  the  entire  world.  It  was  also 
possible  to  supply  airships  with  the  current. 
A  company  was  founded  for  a  passenger 
and  parcel  service  without  gasoline  which 
began  serving  all  important  parts  of  the 
world. 

"At  the  same  time  the  Peace  Conference 
at  The  Hague,  which  represented  all  civi- 
lized nations,  decided  on  the  complete  dis- 
armament of  all  the  world,  without  any 
restrictions.  By  this  time  every  great 
Power  had  established  a  fleet  of  unmanned 
aeroplanes  loaded  with  thousands  of  bombs, 
which  were  to  release  by  wireless  current 
at  the  first  mobilization  of  the  enemy  over 
all  his  important  towns.  In  this  way  every 
hostile  town  and  base  would  be  reduced  to 
ruin  in  a  few  hours.  This  meant  that  there 
could  no  longer  be  any  war." 

Other  imaginary  inventions  described  by 
the  writer  include  an  American  "spectral 
film,"  which  brought  the  pictures  of  dis- 
tant events  as  they  happened  to  the  theatre 
and  private  house.  Another  invention  dis- 
pensed with  the  use  of  coal  and  gas  by 
preserving  the  heat  and  light  of  the  sun. 
Traffic  problems  in  the  world's  great  cities 
were  solved  by  setting  pavements  and 
streets  in  motion.    The  article  concludes : 

"Finally,  as  inventions  reduced  the  trou- 
ble of  living  more  and  more,  the  people 
began  to  lose  the  use  of  their  limbs,  since 
everything  was  done  for  them,  a  world  con- 
ference was  assembled,  which  forbade  any- 
one inventing  anything  more."  Sic  temper 
gloria  mundi. 


LOCATING  UNDERGROUND  ORES 
BY  ELECTRICITY. 

{Continued  from  page  441) 
about  the  center  of  the  primary  coil,  the 
magnetic  field  will  be  weakened,  but  llie 
contour  lines  are  not  distorted  from  tlieir 
normal  circular  form.  However,  with  a 
sufficient  number  of  sets  of  contours,  the 
presence  of  the  conducting  orebody  is 
positively  determined. 

If  the  conductor  be  close  to  the  surface, 
or  nearly  in  the  plane  of  the  primary  coil, 
the  galvanometer  shows  a  minimum  read- 
ing when  the  same  amount  of  magnetic 
flux  is  inclosed  by  both  exploring  coils,  but 
this  minimum  reading  is  not  zero,  since 
some  current  will  flow  between  the  ex- 
ploring coils,  probably  due  to  a  difference 
in  phase  caused  by  the  angle  between  the 
lines  of  force  in  the  two  magnetic  fields. 
.  The  presence  of  water  courses,  puddles 
on  the  surface  or  solutions  in  the  ground 
does  not  affect  this  method,  since  liquids 
are  not  appreciably  conductive  of  the  low- 
voltage  oscillating  current  that  is  induced. 
Contour  lines  about  any  given  center  can  be 
practically  duplicated  at  any  time,  regard- 
less of  the  weather  conditions  or  variations 
in  ground  water. 

Theoretically,  the  presence  of  a  conduc- 
tor within  a  distance  from  the  plane  of  the 
primary  coil,  of  two-thirds  the  diameter  of 
the  primary  coil,  will  measurably  affect  the 
magnetic  flux  in  the  plane  of  the  coil.  This 
has  been  proved  practically,  so  that  if  the 
primary  coil  is  200  ft.  in  diameter,  a  con- 
ductor within  130  ft.  of  the  surface  or,  if 
the  primary  coil  is  400  ft.  in  diameter,  a 
conductor  within  260  ft.  of  the  surface,  will 
cause  distortion  of  the  contour  lines. 

The  field  development  of  this  method 
was  carried  out  in  the  Joplin  district,  Mis- 
souri. Of  the  ores  found  in  this  district — 
namely,  zinc  blende,  galena  and  pyrite — 
the  zinc  blende  is  not  a  conductor  and  can- 
not be  determined,  but  the  galena  and  pyrite 
may  be  determined  satisfactorily.  Both 
galena  and  pyrite  are  conductors,  and  as 
this  electrical  method  does  not  distinguish 
the  quality  of  the  conductor,  drilling  is  nec- 
essary after  determining  the  orebody  elec- 
trically for  identifying  the  mineral  by  drill 
cuttings.  This  disadvantage  is  somewhat 
offset  by  the  fact  that  all  three  minerals 
are  ofen  closely  associated,  so  that  the 
electrical  determination  of  an  orebody 
consists  of  either  galena  or  pyrite  may 
incidentally,  by  drilling,  develop  an  orebody 
of  blende. 

In  order  to  operate  with  efficiency,  an 
automobile  truck  has  been  equipped  with 
self-exciting  alternating-current  generator, 
driven  by  a  gasoline  engine,  and  all  instru- 
ments and  machinery  required  for  produc- 
ing the  high-frequency  oscillating  magnetic 
field  are  mounted  in  the  truck  body.  An 
instrument  box  containing  galvanometer, 
current  rectifiers  and  switches  is  provided 
for  convenience  and  portability  when  ex- 
ploring the  magnetic  field  to  determine  the 
contour  lines.  Portable  reels  carry  the 
necessary  wires.  The  entire  equipment 
may  be  placed  in  the  truck  for  moving. 

For  prospecting  in  any  mineralized  dis- 
trict, the  first  requirement  is  the  tabulation 
of  all  ores  liable  to  be  found  in  that  dis- 
trict, with  their  degrees  of  conductivity. 
I  have  been  unable  to  find  any  record  of 
work  done  toward  such  a  tabulation  of 
ores.  A  partial  list  of  minerals,  with  their 
comparative  degrees  of  conductivity,  has 
been  determined  for  this  work,  as  shown 
in  the  accompanying  table. 

COMPARATIVE    ELECTRICAL  CONDUCTIV- 
ITY OF  MINERALS 

Proustite   ,   18 

Cerargyrite    0 

Pyrargyrite    20 

Bromirite    0 

Chalcocite    115 


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502  THE  ELECTRICAL  EXPERIMENTER  November,  1917 


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Chalcopyrite    115 

Enargite    110 

Tetrahedrite    110 

Malachite    0 

Chrysocolla   :   0 

Cuprite    0 

Tenorite   0 

Azurite    0 


[<  Oja  meter  ofFr/mory  Co,/- . . 

 Fit  2 


Arrangement  of  Electrical  Prospecting  Ap- 
paratus and  Plot  of  the  Magnetic  Field. 

Atacamite    j? 

Galena    105 

Tamesonite    40 

Boulangerite    90 

Zinkite    US 

Blende   0 

Hydrozincite    0 

Calamine    0 

Smithsonite    0 

Willemite    0 

Magnetite    120 

Specular  Hematite    50 

Pyrite   110 

Red  Hematite    0 

Limonite    0 

Pyrolusite    115 

Psilomelane    0 

Manganite    0 

Braunite    0 

Hausmanite    0 

Rhodonite    0 

The  main  difficulties,  in  the  district  where 
the  method  was  developed,  are  the  frequent 
occurrence  of  pyrite,  which  is  of  no  value, 
and  the  nonconductivity  of  zinc  blende, 
which  is  the  most  desirable  ore.  The  Joplin 
district,  however,  has  proved  a  most  ad- 
vantageous place  for  the  development  of 
this  method,  since  the  ore-bodies  are  gen- 
erally less  than  200  ft.  below  the  surface, 
and  facilities  for  experimental  work  are 
ample  and  convenient.  Field  experiments 
have  been  carried  on  for  over  a  year.  Of 
eleven  locations  tested  by  drilling,  after 
the  electrical  observations  had  indicated  a 


Actual  Distorted  Contour  Lines  Obtained  in 
the  Field.  The  Dotted  Areas  Result  From, 
and  Indicate  the  Presence  of  an  Ore-Body. 


conductor,  seven  proved  the  presence  of 
the  conductor,  six  cases  being  pyrite  and 
one  case  galena.  The  four  locations  not 
proved  by  drilling  occurred  in  the  early 
part  of  the  work,  before  enough  data  had 
been  accumulated  to  assure  proper  inter- 
pretation of  the  contour  lines. 


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REAL  BARGAIN  SALE 

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231  Fulton  Street  New  York 


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November,  1917 


THE  ELECTRICAL  EXPERIMENTER 


503 


Scientific  Exchange  Columns 

UNDOUBTEDLY  you  have  at  the  present  time  some  things  for  which  you  have  no  further  use.  Do  you  wish  to  exchange  them  for  something, 
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The  Very  people,  the  Only  people,  who  could  possibly  have  a  use  for  your  things  read  this  journal.  More  than  75,000  interested  people 
will  see  your  ad.  It  is  furthermore  the  cheapest  advertising  medium  for  you  in  the  country.  Dealers'  advertising  accepted  in  Opportunity 
Exchange  Columns  only. 

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OVER  80,000  PEOPLE  READ  THIS  JOURNAL 


3rf 


FOR  SALE  CHEAP— One  new  Power's  6-A  Mo- 
tion Picture  Outfit;  used  four  weeks;  would  con- 
sider an  immediate  cash  offer.  Austin  Miller, 
Erwin,  Tenn.  

FOR  FIRST  32  numbers  of  Electrical  Experi- 
menter,  comprising  first  two  volumes  and  eight 
number  volume  three,  will  exchange  copies  of 
Scientific  American,  complete  from  Jan.  1,  1916, 
thru  April  28,  1917.  Write,  stating  condition  of 
copies.  James  Gaston  Towery,  145  McDonough  St., 
Decatur,  Ga.  

FOR  SALE— 1J4  lb.  No.  25  DCC  copper  wire, 
$1.15;  100  ft.  No.  8  DBRC  copper  wire,  5c  foot. 
Four-cylinder  auto  spark  coil,  $8.  Knapp  leader 
motor,  $2.  Underwood  No.  5  typewriter,  $35,  ex- 
cellent condition.  Meccano  No.  3,  $3.50.  Inger- 
soll  wrist-watch  (new),  $2.  Stamp  collection  and, 
album,  $1.  WANTED— Volumes  1  and  2  of  E.E. 
Write,  Alon  Sliewman,  Tionesta,  Pa. 

FOR  EXCHANGE— My  complete  wireless  re- 
ceiving  set,  value  about  $60,  for  a  Smith  Motor- 
wheel  in  good  condition.  G.  M.  Burchnell,  Mon- 
roeville,  Ind. 

WILL  SELL — Colonial  110  direct,  three-speed 
fan,  $4.  6-18-volt  Menominee  Motor,  $3.  Marconi 
2-inch  Transformer  Coil,  $3.50.  Terms  c.  O.  d. 
express.    Robert  Haag,  Chadwick,  111.  

FOR  SALE — Wireless  instruments  at  bargain. 
Send  red  stamp  for  list  and  prices.  W.  F.  Went- 
ling,  Cumberland  Valley,  Pa.  

WILL  PAY  CASH  for  $18  Omnigraph  and  dials,  j§ 
if  in  good  shape.  Edward  Law,  Jr.,  216  Sycamore  = 
St.,  Clarksburg,  W.  Va.   g 

FOR  SALE — Two  International  Correspondence  g 
Schools'  automobile  reference  volumes,  and  Seneca  H 
plate  camera,  4x5.     Geo.  Bruenn,  Durand,  Wis. 

I  WILL  TRADE  my  chemical  and  wireless  _\ 
laboratory  for  an  automatic  telegraph  key.  All  S 
inquiries  answered.    A.  L.  Cox,  Jr.,  Glendale,  Ky.  m 

BARGAINS— Seneca  Camera  2'4x3^i  R.R.  lens  ■ 
trio  shutter  and  outfit,  $10.  Cub  camera  3 14x3 H,  m 
$1.     Ernest  Rerucha.  Brainard,  Nebr. 

FOR  SALE — $50  motor-generator:  runs  as  motor  H 
on  110  A.C.,  Vi  H.P.  develops  3,800  r.p.m.  As  ■ 
generator  will  charge  8  v.  60  amp.  storage  bat-  H 
teries.  First  $15  check  takes  it.  Atlee  Gulledge,  H 
Box  592,  Fort  Pierce,  Fla.    §§ 

WANTED— Motorcycle,  light  weight  Indian  pre-  B 
f erred;  must  be  in  A-l  condition,  no  junk  wanted.  Hj 
Also  want  motorbike,  carbide  generator,  omni-  m 
graph  and  vibroplex.  Have  $6  toy  picture  ma-  m 
chine  for  $3.    O.  C.  Miller,  Bayard,  Kansas.   a 

FOR  SALE— 4,000  M.  Loose  Coupler,  $4,  cost  ■ 
$10;  Brandes  2,000  ohm  head-set,  $3;  1/20  H.P.  m 
Knapp  A.C.  motor,  $3.50;  Knapp  Tvpe  S  Dvnamo  s 
Motor,  $1.50;  1"  Coil,  $2.  Write  for  further  par-  m 
ticulars.  All  letters  answered.  Ray  J.  Farmer,  m 
Monteguma,  Iowa.  - 

COMPLETE  I.  C.  S.  Electrical  Engineering  ■ 
Course,  Cost  $145.  Never  been  used.  Will  sell  m 
half  price.  Swap  for  Saxaphone.  George  Niman,  S 
Polo,  111.   jj 

BARGAINS — $35  Eclipse  bicycle,  coaster  brake  ■ 
model,  $20;  $15  Guitar  outfit,  $11;  Bov  Scout  out-  m 
fit,  including  puttees,  suit  size  16  and  haversack, 
$4.    All  guaranteed  in  A-l  condition.    Cash.  Want 
phonograph  and  records.    Arthur  Ellwein,  Wrights- 
ville,  Pa.  b 


I.  C.  S.  course  on  electric  lighting  in  four  vol- 
umes, $8.  Dyke's  Auto  course,  with  models,  $11; 
bookkeeping  course,  $2.50.  Will  sell  or  exchange 
for  omnigraph.    A.  Hersee,  Burlington,  Ont.,  Can. 

FOR  SALE  —  International  Correspondence 
Schools'  electrical  course  sell  for  $35.  Write  P. 
R.  Glasgow,  1704  Lee  Rd„  Cleveland,  Ohio. 

FOR  SALE — Carlisle  &  Finche  Electric  Motor. 
Good  condition.  Price  $10.  Earl  Cook,  Bernards- 
ton,  Mass. 

FOR  SALE — One  Premo  film  pack  camera,  post- 
card size,  slightly  used,  best  of  condition.  Price 
R.  Roesch,  13332  Forest  Hill  Av.,  East 


$10.  E. 
Cleveland, 


Ol 


no. 


FOR  SALE — Storage  battery,  motors,  wireless 
goods,  etc.,  or  will  exchange  for  motorcycle,  or 
bicvele  engine.  Paul  Olnhausen,  824  Chester  Ave., 
East  Liverpool,  Ohio. 

FOR  SALE— Hudson  Audion  Amplifier  Bulb, 
new,  $5;  ?4"  Spark  Coils,  $1.25;  large  Accurate 
Vortammeter,  $2;  also  chemicals.  AH  answered. 
J.  C.  Swimmer.  19Q4  Park  PI.,  Brooklyn,  N.  Y. 


FOR  SALE — High-grade  receiving  apparatus,  in 
excellent  condition,  only  in  operation  fur  two  weeks. 
Consists  of:  Tubular  audion  (both  filaments), 
$3.25.  Duck's  N.A.A.  receiving  transformer,  cost 
$17.25  for  $12.50.  Two  Murdock  .001  variable 
condensers,  $2.50  each.  One  Clapp  Eastham  for 
$3;  small  .0005  Murdock,  $2.  Rheostat  cabinet, 
Murdock  3,000  phones,  all  for  $4.50,  or  separate 
offers.  These  instruments  are  all  in  perfect  con- 
dition. Also  Murdock  change-over  switch  and 
miscellaneous  apparatus.  Sending  instruments — 
have  never  been  used — 10,000  volt  old  model  Thor- 
darson,  $12.50.  Four  sections  Murdock  sending 
condenser  at  $1.50  each.  Oscillation  transformer, 
cost  $6.75  for  $3.50.  Key,  fine  spark  gap  motor, 
etc.  for  offers.  Am  going  to  join  Naval  Reserve. 
Write  offers  anvway.     Address  H.   W.  Toomey, 

P.  O.  Box  127,  "Deer  Lodge,  Montana.  

SELL — Navy  coupler:  Perikon  detector;  variom- 
eter; 34"  spark  coil;  $5  Erector;  Encyclopaedia 
Britannica.  Wrue  for  list.  Carlton  Caswell, 
Franklin  St.,  Framingham,  Mass. 

1913  Excelsior  Autocycle  for  sale.  Needs  over- 
hauling. Best  offer  takes  it.  Engine,  magneto  and 
carburetor  in  good  condition.  Horn,  lights,  speed- 
ometer. Will  swap.  R.  E.  Fisher,  c/o  N.  E. 
Power  Co.,  Woonsocket,  R.  I. 


Illllllllllllllllllllllllllllllllll 

"WANT  TO  SWAP"?  | 

Do  you  realize  that  these  "Scientific  Ex-  j| 

change  Columns"  are  the  World's  most  re-  ji 

nowned   "Swap"  market?      "THE  ELEC-  m 

TRICAL  EXPERIMENTER"  prints  80,000  jj 

copies  of  this   issue;   that   means  that  at  _\ 

least    160,000    readers    see   this   page   and  _\ 

probably  a  great  many  more.    Our  readers  g 

who   advertise   here   seldom   advertise   the  gj 

same  thing  twice — usually  within  five  days  g 

after  the  issue  is  out  the  advertised  article  g 

has  been  sold,  or  swapped.    The  many  testi-  J 

monials  which  we  print  here  from  time  to  H 

time  are  ample  proof  of  the  almost  miracul-  g 
ous  pulling  power  of  these  columns. 

Look  around  in  your  attic  or  workshop  H 

and  you  will  find  dozens  of  long  forgotten  g 

articles,  useless  to  you  now,  but  very  use-  H 

ful  to  someone  else.    At  a  ridiculously  low  H 

cost  you  can  either  sell  or  swap  such  articles.  jj 

And  remember  this  fact:  The  U.  S.  Postal  = 

Laws  protect  you.     No  one  can  "do"  or  §= 

cheat  you.     Of  3,495   "ads"  published  in  jj 

these  columns  during  the  past  five  years,  m 

only  twelve  complaints  were  reported  to  us,  |jj 

and  each  and  every  one  was  adjusted  to  jj 
the  full  satisfaction  of  the  complainant. 

It  matters  not  if  you  have  old  books  or  _\ 

magazines,  a  kodak,  electrical  or  chemical  g 

apparatus,    scientific    instruments,   bicycles,  jj 

typewriters,   moving  picture  machines,  air  g 

rifles,   watches,    structural   toys,   etc.,   etc.  g 

All  these  and  countless  others  can  be  speed-  g 

ily  disposed  of  here.  Try  it  and  be  con-  g 
vinced. 


a 


WANTED— Thordarson  type  R  Yz  K.W.  110 
v.  60  cycle  A.C.  transformer  in  good  condition  at 
a  bargain.  Also  Tesla  coil.  Harold  Janeway,  L. 
Box  No.  1,  Edmonds,  Wash. 

TELEGRAPH  APPARATUS  FOR  SALE— 
Consisting  of  omnigraph,  automatic  transmitter 
(No.  2),  key  and  sounder  (20  ohm  Bunnell  Com- 
bination set).  Slightly  used.  Excellent  condition, 
$15.  Frank  T.  Tomazevic,  12  Stagg  St.,  Brooklyn, 
N.  Y.  

WANT— to  1HP.  500  volt  motor  or  gen- 
erator, Weston  or  Keystone  portable  ammeter  0-50 
amperes,  voltmeter  0-150  volts.  Will  buy  for  cash 
or  exchange  for  radio  apparatus.  Have  an  excel- 
lent Keystone  milliampere  meter;  fine  for  research 
work.  Samuel  Cohen,  1936  Pitkin  Ave.,  Brooklyn, 
N.  Y.   

SACRIFICE— Wireless  apparatus,  Tesla  _  coil, 
camera,  books,  copies  of  E.  E.,  Steffey  bicycle 
motor.  Write  for  immediate  offer.  Stamp,  Nor- 
man  Himes,  Norwich,  Conn.  

FOR  SALE  CHEAP— Wireless  and  Electrical 
apparatus.  Want  taps  and  dies.  James  Dicker- 
man,  20  Rush  St.,  Somerville,  Mass. 


FOR  SALE  OR  EXCHANGE— A  Chambers' 
Loose  Coupler,  good  condition,  $5.  Might  take 
good  wireless  apparatus.  George  Coxe,  Olean, 
N.  Y.  

F<  IR  SALE — One  2J/2  horse  power  Shaw  bicycle 
motor,  run  less  than  one  hundred  miles,  good  as 
new;  it  has  a  high  tension  magneto.  Also  have 
for  sale  one  Henderson  motorcycle,  1914  model,  15 
horse  power,  no  magneto.  Will  sell  the  Shaw 
motor  for  $30,  and  the  Henderson  for  $35,  it  is 
all  complete  but  the  magneto.  Henry  Michelsen, 
Gladbrook,  Iowa.   

WANT — Goodell  Pratt  Lathe  with  slide-rest  for 
$60,  regenerative  receptor.  $18  Mu1ti-Audi-Fone, 
$14.75.  $23  Multi-Audi-Fone,  $18  New.  Francis 
Prey,  102  Heath  St.,  Somerville,  Mass.  

FOR  SALE — Duck's  Navy  Type  Receiving 
Transformer,  2,500  meters,  cost  $19.50,  sell  $12. 
Murdock  366  43  plate  Condenser,  $3.  Brandes 
2,000  ohm  receivers,  $3.  1  K.W.  Aerial  Switch, 
$2.  All  used  one  month.  Will  sell  all  for  $15. 
Lloyd  Ross,  R6,  Albert  Lea,  Minn.  

FOR  SALE — One  new  omnigraph,  never  beerv 
used,  cost  $18,  will  sell  for  $15.  Change  of  plans 
is  reason  for  selling  Ross  Hahn,  1325  Arm- 
strong Ave.,  Knoxvilfe,  Tenn.  

FOR  SALE — Interstate  receiving  outfit,  $3; 
banjo-mandolin  $4,  cost  $8;  mirroscope  (gasj,  $2. 
Dewitt  Palmer,  1230  N.  60  St.,  Philadelphia. 

1).  C.  Electric  Motor,  220  V.  1/7  H.P.,  almost 
new.  Will  exchange  for  A.  C.  Motor  or  X-Ray 
apparatus  with  large  condenser,  or  $15  cash.  Wm. 
Truchan,  3776  Madison  St.,  Gary,  Ind.  

ROLL  top  desk,  single  pedestal;  York  snare 
drum;  Powers'  No.  6  motion  picture  machine; 
Edison  "B"  Mechanism;  automatic  stereopticon, 
capacity  eighteen  slides;  twenty  sets  colored  song 
slides;  E.  I.  3,000  ohm  phones,  $2.95;  offers  con- 
sidered. Good  visible  typewriter,  $25.  Verner 
Hicks,  Marion,  111.  

HALF  PRICE — $60  lathe;  $30  drill  press;  $4 
emery  wheel;  hand  tools;  work  bench;  wood  tools; 
1-5  K.W.  transformer;  i5"  coil,  motor,  dynamo; 
all  select  instruments.  Chas.  Horton,  17  Euclid, 
RidgelTeld  Park,  N.  J.  

SACRIFICE — $100,  10,000  meter  Audion-min- 
eral  cabinet  set,,  $65,  5,000  miles  on  Galena. 
9,000  Audion,  almost  new;  $100  transmitting  ap- 
paratus, cheap.  Write,  Bud  Wickersham,  170 
Valley  St.,  San  Francisco,  Cal.  

FOR  SALE  OR  TRADE— Rochester  Optical 
Co.  8  x  10  view  camera,  rising  and  falling  front, 
double  swing,  reversible  back,  with  Bausch  &  Lomb 
automatic  shutter,  and  combination  view  and  por- 
trait lens,  three  double  plate  holders,  no  tripod, 
or  carrying  case.  Cost  $85.  Mea,  six  cylinder, 
high  tension  magneto,  runs  anticlockwise.  Cost 
$100.  Wizard,  direct  current  generator,  6  am- 
peres, 20  volts.  Cost  $18.  Motsinger  Auto 
Sparker  direct  current  generator,  6  amperes,  20 
volts.  Cost  $25.  Five  H.P.  upright,  slide  valve 
steam  engine.  No  flywheel,  governor,  or  throttle. 
Cost  $50.  Aeolian  Pianola  Piano  Player,  and  fifty 
rolls  of  music.  Fits  any  piano.  Cost  $350  and 
music  about  $50.  Edison  cylinder  phonograph  with 
cygnet  horn,  and  two  hundred  and  sixteen  two 
and  four  minute  records.  Cost  altogether  $125. 
Will  trade  for  high-grade  wireless  sending  and 
receiving  apparatus,  no  _  home-made  stuff,  Graflex 
camera,  high  power  rifle  or  what  have  you? 
R.  A.  Workman,  Woodward,  Okla. 

SMALL  screw  cutting  lathe,  3  speed  lathe  and  a 
Bnley  watchmaker's  lathe  for  sale  or  exchange. 
Ralph  C.  Morse,  P.  O.  Box  147,  Foxboro,  Mass. 

FOR  SALE — $50  set  Harvard  Classics,  51  bonks, 
new,  $30;  also  15"  spark  coil  without  condensers. 
If  interested  write,  will  send  photo  of  coil  and 
open  bids.  Any  for  less  than  $40  ignored.  Harry 
J.  Frenz,  740  Franklin  Ave.,  Wilkinsburg,  Pa. 

EXCHANGE— New  Flute  &  Piccolo,  worth  $40, 
for  electric  train,  toys  or  apparatus.  What  have 
you?   Arthur  Ohlschlager,  488  Normal  Ave.,  Buffalo. 

EXCHANGE— My  $40  Violetta  complete  Want 
Omnigraph  in  first-class  condition,  even  exchange, 
or  what  have  you  in  wireless  apparatus?  Geo.  A. 
Chandler,  500  N.  Clark  St.,  Chicago,  111. 

WANTED— Copy  of  book  "Michael  Faraday,  His 
Life  and  Work"  by  Sylvanus  Thompson.  Also  an 
ohmeter  of  the  Roller-Smith  type  or  a  Wheatstone 
bridge;  must  be  in  first-class  condition,  and  include 
galvanometer.  H.  W.  Secor,  c/o  Electrical  Ex- 
perimenter, 233  Fulton  St.,  New  York  City. 


You  benefit  by  mentioning  "The  Electrical  Experimenter"  when  writing  to  advertisers. 


504 


THE  ELECTRICAL  EXPERIMENTER 


November,  1917 


F5 


Opportunity  Exchange 


'yOU  will  probably  find  more  opportunities  and  real  bargains  in  these  columns  than  anywhere  else  in  the  country.  Most  good  things  in 
~  life  are  hard  to  find  and  worth  going  after — these  little  ads  illustrate  that  point;  you  alone  will  be  the  real  loser  if  you  don't  take  the 
time  to  scan  through  these  columns. 

Advertisements  in  this  section  six  cents  a  word  for  each  insertion.    Count  7  words  per  line. 

Name  and  address  must  be  included  at  the  above  rate.  Cash  should  accompany  all  classified  advertisements  vtnless  placed  by  an  accredited 
advertising  agency. 

Ten  per  cent,  discount  for  6  issues,  20  per  cent,  discount  for  12  issues  from  above  rate.    Objectionable  or  misleading  advertisements  not 

accepted. 

Advertisements  for  the  December  issue  should  reach  vjs  not  later  than  October  25. 

OVER  80,000  PEOPLE  READ  THIS  JOURNAL 

EXPERIMENTER  PUBLISHING  CO.,  INC.,  233  Fulton  Street,  New  York,  N.  Y. 


AERONAUTICS 


AERIAL  AGE,  America's  leading  illustrated 
weekly,  presents  the  latest  developments'in  aeronau- 
tics throughout  the  world.  Up  to  the  minute 
technical  information  concerning  aero-engines,  aero- 
planes, accessories  and  patents.  Complete  model 
news  and  instruction.  Trial  subscription  six 
months,  twenty-six  issues,  one  dollar.  Sample  copy 
10c.  Aerial  Age,  280  Madison  Ave.,  New  York 
City,  N.  Y. 


AUCTIONS 


AUCTIONEERS  make  from  $10  to  $50  a  day. 
Free  catalog.  Missouri  Auction  School,  Kansas 
City. 


BOOKS 


TO  GET  BETTER  PICTURES:  Read  the 
Amateur  Photographer's  Weekly;  illustrated;  week- 
ly prize  competitions;  print  criticisms;  many  unique 
features;  $1.50  per  year;  three  months'  trial  sub- 
scription 25c;  Abel  Publishing  Company,  401 
Caxton  Bldg.,  Cleveland-,  Ohio. 

BOYS — Get  my  book  "How  to  Make  a  Com-, 
plete  Telegraph,"  price  10c.  Glen  Jackson,  Ft. 
Recovery.  Ohio.  

30  MAGAZINES — All  different,  late  issues. 
Value  $3.  Yours,  only  25c  prepaid.  Eastern 
Bureau.  New  Egypt.  N.  J.  

LABORATORY  EXPERIMENTS  in  General 
Chemistry,  36  illustrations.  51/  x  7VA,  212  pages. 
A  manual  of  500  carefully  chosen  experiments 
on  the  most  common  elements.  Price  $1  prepaid. 
Ludwig,  299  Broadway,  N.  Y.  C. 

A  BINDER  for  THE  ELECTRICAL  EXPERI- 
MENTER will  preserve  your  copies  for  all  time. 
Price,  50c.  Postage  on  3  lbs.  is  extra.  Send  for 
one  today.  Experimenter  Publishing  Co.,  233  Ful- 
ton St.,  New  York  City. 

FIRE  SALE  OF  SLIGHTLY  DAMAGED 
BOOKS.  Due  to  fire  in  our  stock  rooms,  a  great 
many  of  our  books  were  water  stained,  but  not 
otherwise  damaged.  Rather  than  dispose  of  them 
to  dealers  we  prefer  to  give  our  readers  the  bene- 
fit. Look  at  this  list!  Our  celebrated  Wireless 
Course,  160  pages,  400  illustrations;  Experimental 
Electricity  Course,  160  pages,  350  illustrations;  How 
to  Make  Wireless  Sending  Instruments.  These 
three  books  for  $1.00  prepaid.  Regular  selling 
price  of  these  three  books  is  $2.50.  We  guarantee 
you  will  be  satisfied.  Experimenter  Publishing  Co., 
Inc.,  233  Fulton  St.,  New  York  City. 

OLD  E.E.  BACK  NUMBERS— We  have  some 
valuable  old  E.E.  back  numbers  on  hand  as  per 
list  below: 

1915. 
Jan.  . 
Feb.  . 
March 
April  . 
May  . 
Tune  . 
July  .. 
August 
Sept.  . 
Oct.  .. 
Nov  . 
Dec.  . 


.price  each  $.25 


.price  each  $.20 


.15 


March 
April  . 
May  . . 
June  . . 
July  .. 
August 
Sept.  .. 
Oct.  .  . 
Nov.  . . 
Dec.  .. 

1917. 
Tan.  .  . 
Feb.  .. 
March  ....    "      "  " 
1916.  April    ..."  " 

Tan   "       "      .20       May    " 

Feb   "     «      "        Tune  ....    "  " 

July    "      "  " 

We  can  fill  orders  at  once  upon  receipt  of  your 
remittance  and  if  you  have  not  these  numbers  al- 
ready now  is  your  chance  to  get  them  as  they 
probably  will  be  snapped  up  verv  quickly.  Ex- 
perimenter Publishing  Co.,  233  Fulton  St.,  New 
York  City. 


 BUSINESS  OPPORTUNITIES  

SPECIAL  OFFER— Luminous  Paint,  15c;  Sil- 
ver-plating Powder,  15c;  Liquid  Courtplaster,  15c; 
Soap  Bubble  Liquid,  15c;  Straw  Hat  Bleach,  15c; 
Collapsible  Tube  Tooth  Paste,  15c  Resilvering  Mir- 
ror Liquid,  15c;  Polish  for  Tan  Shoes,  15c;  Dress- 
ing for  Tan  Shoes,  15c;  Paint  to  Make  Oil  Cloth, 
15c.  Full  Directions  how  to  make  and  use.  Full 
set  of  10  only  50c.  Remarkable  bargain.  Stamps 
accepted.  Sidney  Specialty  Co.,  233  S.  Fulton  St., 
New  York  Citv. 


CHEMICALS 


URANYL  CHLORID  (Radio-Active)  pure,  lA 
oz.,  75c;  Uranyl  Bromid  (Radio-Active)  pure,  J4 
oz.,  90c;  LTranyl  Oxid  ( Radio  Active)  pure,  %  oz., 
85c;  Uranium  Metal  fused  (Radio-Active)  1  gram, 
$2.  The  above  are  guaranteed  genuine.  Robert 
J.  Hanchett,  Nestor,  Cal.  

LISCIEN  CHEMICAL  APPARATUS  OUT- 
FITS. Circulars,  four  cents.  Clarence  Appel, 
Mathews  Avenue.  Knoxville,  Pittsburgh,  Pa.  

RADIUM  ORE.  Sample  Twenty-five  Cents. 
Clarence  Appel,  Mathews  Avenue,  Knoxville,  Pitts- 
burgh, Pa. 

ELECTRICAL  SUPPLIES  AND  APPLIANCES 

FLASHLIGHTS— No.  5862  2-CELL  BABY 
TUBULAR  Fibre  Short-Circuit-Proof  Case,  Com- 
plete with  Battery  and  Lamp,  75c.  Send  for 
Illustrated  "List  O"  of  Guaranteed  Quality  Cases, 
Lamps,  Batteries,  Hand  Lanterns.  BAER  ELEC- 
TRIC.  Van  Wert.  Ohio.  

F<  IR  SALE — Engines,  half  horse  power  tip. 
Terms  on  sizes  larger  than  one  and  a  half  H.  P. 
Also  Dynamos  on  terms.  H.  J.  Clemmer,  Blue 
Creek.  W.  Va.  

BOYS — I  have  on  hand  Transformers  of  any 
type.  WRITE  ME.  I  can  save  you  money.  My 
special  offer  on  Standard  make  transformers  for 
operating  Electrical  Toys  and  for  your  laboratory. 
Generate  3,  6,  9,  15,  22  volts,  controlled  by  a 
switch  for  $1.85.  Regular  price,  $3.  Have  only  a 
limited  number.  ACT  OUICK.  Further  particu- 
lars FREE.  Willard  Meyers,  950  Garfield  Ave., 
Chicago,  111.  

HELP  WANTED 

THOUSANDS  GOVERNMENT  WAR  PO- 
SITIONS OPEN  to  men  and  women,  18  or  over. 
$100  month.  Rapid  increase.  Short  hours. 
Pleasant  work.  Vacations  with  pay.  Pull  unnec- 
essary. Examinations  everywhere.  Common  edu- 
cation sufficient.  List  positions  free.  Write  im- 
mediately. Franklin  Institute.  Dept.  H-27, 
Rochester,  N.  Y.  

BE  A  DRAFTSMAN — Big  pay;  tremendous 
demand.  Study  at  home;  complete  course;  draw- 
ing instruments  FREE.  Our  students  filling  good 
positions  as  Draftsmen  and  Chief  Draftsmen  with 
Government  and  private  concerns.  We  help  you 
secure  position  when  qualified.  Columbia  School 
of  Drafting,  25  McLachlen  Bldg.,  Washington, 
D.  C. 

MISCELLANEOUS 

LAUGHABLE  CARTOON— One  that  will  make 
your  sides  ache,  send  your  photo  and  25c  (coin). 
PUBLISHERS — I  make  cartoons  and  illustrations 
for  you  also.  Ridley,  Cartoonist,  639  Mont- 
gomery St..  Jersey  City.  

STAMPS— 75,  all  different,  free.  Postage,  2c. 
Mention  paper.    Quaker  Stamp  Co.,  Toledo,  Ohio. 

WE  HAVE  a  limited  number  of  beautiful  art 
pictures  of  the  following  famous  electrical  men  on 
hand.  Nikola  Tesla,  Dr.  Lee  De  Forest,  Guglielmo 
Marconi,  Charles  P.  Steinmetz  and  Reginald  A. 
Fessenden.  These  make  a  handsome  decoration 
for  any  laboratory  or  workshop  and  should  be 
prominently  displayed.  Price  for  five,  prepaid, 
25c.  Experimenter  Pub.  Co.,  233  Fulton  St.,  New 
York  City.  

BIG  BARGAIN  IN  TENNIS  RACKETS— 
We  have  a  small  supply  of  Tennis  Rackets,  made 
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PATENT  ATTORNEYS 


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0  Address 


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Dept.  744B 


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Just  what  you  need  to  know  to  succeed  in  ELECTRICITY 


READ  THIS  PARTIAL  LIST  OF  CONTENTS 
fijn  1  Contains  348  pages,  3S8  illustrations.  Electrical 
I^IO*  1  signs  and  symbols — static  and  current  electricity 
—  primary  ceils — conductors  and  insulators — resistance  and 
conductivity — magnetism — induction  coils — dynamo  principles 
■ — classes  of  dynamos — armatures — windings — commutation — 
brushes,  etc. 

M„  O  Contains  348  races,  394  illustrations.  Motor 
*  principles — armature  reaction — motor  starting — 
calculations — brake  horsepower — selection  and  installation  of 
dynamo  and  motors — galvanometers — standard  cells — current 
measurement  —  resistance  measurement  —  voltmeters  ■ —  watt- 
meters— watt  hour  meters — operation  of  dynamos — operation 
of  motors,  etc. 

No  3  f°nfains  300  pages.  423  illustrations.  Distribution 
systems — uires  and  wire  calculations — inside,  out- 
side and  underground  wiring — sign  flashers — lightning  pro- 
tection— rectifiers — storage  battery'  systems,  etc. 
No  A  Contains  270  pages.  379  illustrations.  Alternating 
current  principles — alternating  current  diagrams 
■ — the  power  factor — alternator  principles — alternator  con- 
struction— windings,  etc. 

No.   5     r"nfains  320  pages.  B14  Illustrations.    A.  C  Motors 
— synchronous  andinduction  motor  principles — A.  C. 
commutator  motors — Induction  motors,   transformers;  losses, 
construction,    connections,    tests — converters — rectifiers,  etc. 
No.    6    r"nrains  208  pages.  472  illustrations.  Alternating 
v    current  systems — switching  devices— circuit  break- 
ers— relays — lightning  protector  annaratus — regulating  devices 
■ — synchronous  condensers — Indicating  devices — meters — power 
factor  indicators — wave  form  measurement — switch  boards,  etc. 
No     7     fnn,ains  310  pages.  379  illustrations.  Alternating 
•    '      current,  wiring  power  stations — turbines :  manage- 
ment. seWf'on.  location,  erection,  testing,  running,  care  and 
repair — telephones,  etc. 
No.   8   Oon'ains  332  pages.  43B  Illustrations.  Telegraph 
At±     _,    ,        —simultaneous    telegranhv    and    telephony  — 
^•x    wireless— electric  h«lls— electric  lie*Hn"— photometry,  etc. 
~  -  NO.    9  rm,ai"s  322  paees.  627  illustrations.  El"c- 
^k.   .        "    trie  railways — electric  locomotives — car  lleht- 
inc— (roller  r-a r  nnention — miscellaneous  applications— 
-"lotion  nMin-p^ira.,  engine  i-nition — automobile  self- 
^^tar"-s  and  lii?t->*ine  Srstems.  eWtri"  veMoles  etc. 
Nr»    Ifl  fc^'fins  513  pages.  599  illustrations. 
THEO.        ^^'«-».  iu  Eleva»nrs— cranes— pumns— air  enm- 
„n  pressors— electric  beating  —  ele-tric  welding- 

AUDELotlyU.  soldering   and   brazine — industrial  electro- 

79  Fifth  Avenue  Ak.  lysls — electro  plating — electro-therapeutic 
il  nun  ^yciiuu  —X-rays.  etc. 

New  York,  N.  Y.  ^Also  a  complete  12fi-nage  rendv 

Please  submit  me  for  ^  reference  irujex  of  the  complete 
examination  Hawkins  ^linrnrv.  This  index  has  been 
Electrical  Guides   (price  planned  to  render  easily  ac- 

$1  each).  Ship  at  once,  pre-  "^eessihle  all  the  vast  infer 
paid,  the  10  numbers.    If  sat-  mi  Hon  conteino^  i„  «,„ 

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within  seven  days  and  to  further  ^'"  electrical  eruides. 
mail  you  $1  each  month  until  paid,  There  are  over  13,- 

-A.5*"1     oross  refer- 
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Reference   E.E. 


E 


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OVER 

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ILLUST. 


POPULAR ELECTRICAL   NEWS  ILLUSTRATED 


DAYLIGHT  SIGNALING 
WITH  SEARCH 


I  Tell  You 
You  Can! 


Be  a  success  and  command  big  pay.   You  can 

easily  do  it  if  you  will  only,  prepare  yourself!  Why 
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If  you  have  a  common  school  education  you  can  easily  qualify  at  home  bv  my  new 
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V\  L.  L.  COOKE,  Chief  Engineer 

^V^n\  CHICAGO  ENGINEERING  WORKS 

'  Room  22-441  Cass  St.  CHICAGO,  ILL. 


December,  1917 


THE  ELECTRICAL  EXPERIMENTER 


505 


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to    Chemcraft  owners. 


Chemcraft  No.  2  is  much  larger  than  the  No.  1 
Bet.  It  contains  32  differenl  Chemicals  and  a  lib- 
eral assortment  of  Apparatus  and  equipment. 
There  are  many  rare  and  valuable  Chemicals  In- 
cluded in  this  outfit  which  represents  the  biggest 
value  ever  put  on  market  for  such  a  low  price. 
The  instruction  book  which  comes  witli  this  set 
gives  directions  for  working  nearly  a  hundred  won- 
derful experiments  and  after  you  have  used  the 
set  for  a  little  while  you  will  be  able  to  devise 
countless  additional  experiments  of  your  own. 

livery  purchaser  of  Chemcraft  No.  2  receives  a 
Chemcraft  service  card,  and  is  entitled  to  a  free 
subscription  to  the  Chemcraft  Chemist.  This  is 
(lie  biggest  kind  of  a  help  in  carrying  on  your  ex- 
perimenting and  no  one  should  overlook  this  offer 


CHEMCRAFT  No.  I  Price  Delivered  SI. 25 

West  of  the  Mississippi  and  Canada  $1.50 

This  is  a  dandy  set  at  a  very  reasonable  price. 
With  it  you  can  work  lots  of  wonderful  experiments 
each  one  of  which  can  be  repeated  many  times. 
There  are  14  different  Chemicals,  test  tubes,  glass 
tube,  measures,  etc..  together  with  the  No.  1 
Chemcraft  hook  which  gives  cumplete  directions, 
explains  all  the  experiments  in  a  clear,  interesting 
manner,  and  tells  many  wonderful  and  interesting 
things  about  Chemistry. 

With  Chemcraft  No.  1  you  can  make  fire  ink  and 
fuses;  you  can  bleach  colors,  test  water,  prepare 
chlorine,  manufacture  ammonia,  gun  powder,  col- 
ored fires,  black  ami  colored 
inks;  you  can  prepare 
magic    inks    and  papers, 
change  water  into  wine  and 
wine  into  water,  pour  ink 
and  milk  from  same 
vessel  and  do 
no   end  of 
'  other   \v  o  n- 
d  e  r  f  u  1 
things. 


CHEMCRAFT  No.  3 
Price  Delivered  $5.00 
West  of  the  Mississippi  and  Canada  $6.00 

The  No.  3  Chemcraft  is  the  biggest  and  most 
complete  Chemical  set  on  the  market.  This  set 
contains  48  different  Chemicals  all  of  which  are 
carefully  chosen  because  of  their  many  interesting 
reactions.  A  large  assortment  of  valuable  appara- 
tus is  included,  among  which  is  a  blowpipe,  alcohol 
lamp,  8  test  tubes,  test  tube  holder,  test  tube 
brush,  measures,  measuring  spoon,  gas  delivery 
tube  and  stopper,  glass  tube,  stirring  rod,  and 
other  miscellaneous  equipment. 

The  Chemcraft  book  for  outfit  No.  3  is  complete 
in  every  detail.  It  contains  230  experiments  and 
gives  the  user  a  complete  course  in  Chemistry  in 
addition  to  furnishing  all  kinds  of  fun. 

Every  owner  of  the  No.  3  Chemcraft  set  is  also 
entitled  to  Chemcraft  service  and  a  free  subscrip- 
tion to  the  Chemcraft  Chemist. 
Your  local  dealer  probably  has  the  Chemcraft  outfits  in  stock.    In  case  he  hasn't,  however 
we  will  supply  you  direct  upon  receipt  of  price.    Prompt  delivery  guaranteed. 

CHEMICALS  AND  CHEMICAL  APPARATUS 

„f  Y°.U  hav-M  a  1cnemicJ>l  laboratory?  No  experimenter  should  be  without  one.  A  knowledge 
chemical  experiments"33'8  greatest  value  to  you  and  there  is  nothing  more  interesting  than 

We  are  specially  equipped  to  meet  the  requirements  of  the  experimenter  for  chemical  sup- 
plies. Let  us  know  your  wants.  Our  catalog  lists  nearly  200  chemicals,  all  kinds  of  apparatus 
many  books  on  chemistry,  and  gives  valuable  tables  and  other  information.  Sent  to  any  address 
upon  receipt  of  10c  in  U.  S.  stamps  or  coin.  auuress 


You  know  I  never  put  anything  on  the  market  until  I'm  sure  it's  the  best  of  its 
kind.  I  wouldn't  risk  losing  the  friendship  of  the  tens  of'thousands  of  you  boys 
who  know  from  experience  with  Erector  and  my  other  toys  that  I  always  put 
the  finest  stuff  into  everything  I  make.   Well !  The 


CHEMISTRY  OUTFIT 

is  no  exception.  It's  one  of  the  finest  outfits  ever  manufactured  for 
junior  chemists.  Some  of  the  best  known  chemists  of  the  country 
tell  me  they  never  saw  anything  that  begins  to  compare  with  it. 

If  you're  going  to  get  a  Chemistry  Outfit — and  every  boy  should 
who  likes  scientific  things  and  loads  of  fun — be  sure  to  get  the 
Gilbert  Chemistry  Outfit.  It's  the  only  one  that  enables  you  to  gen- 
erate your  own  electricity  through  chemistry. 

It  is  the  only  one  having  a  wet  cell  and  equipment  for  electroplating  and 
nickel  plating. 

With  the  Gilbert  Chemistry  Outfit,  you  learn  a  lot  about  the  wonderful 
science  of  chemistry,  and  your  friends  will  marvel  at  your  ability.  You 
can  make  soap,  disappearing  ink,  make  an  egg  pass  through  the  narrow 
neck  of  a  bottle,  replate  spoons,  knives  and  forks  and  do  counties:  / 
other  wonderfully  interesting  and  mystifying  things.  / 

A  large,  beautifully  printed  manual,  containing  an  elementary  / 
course  in  chemistry,  is  included  in  each  set.  / 

Your  local  toy  dealer  should  have  this  set  in  stock.    If  he  * 
hasn't,  write  us  and  we'll  tell  you  who  has.     Price  $3.00  >* 
(Canada  $4.50). 

Mail  back  the  coupon  today  for  a  free  copy  of  my  mag- 
azine for  boys'  "Gilbert  Toy  Tips,"  which  explains  all 
about  my  other  toys  and  the  Gilbert  Engineering  In- 
stitute for  Boys.  / 


Mr. 
A.  C. 
Gilbert, 
Pres. 
TTHE  A  C. 
GILBERT  CO., 
160  Blatchley  Ave., 
New  Haven,  Conn. 


President. 


/         Please  send  me  a.  free  copy 
of  "Gilbert  Toy  Tips"  which 
tolls    all    about    the  "Gilbert 
Engineering  Institute  for  Boys  " 


The  A.  C.  Gilbert  Company,     1  New  Having  con™e 

CANADIAN  REPRESENTATIVES,  Menzies  &  Co.,  Limited,  Toronto,  Ont. 


City 


You  benefit  by  mentioning  "The  Electrical  Experimenter"  when  writing  to  advertisers. 


506 


THE  ELECTRICAL  EXPERIMENTER 


December,  1917 


Electric 
Columbia 
Grafonolas 

at$135,$145,$185  and  $240 


r  I^HE  first  time  you  hear  an  electric- 
ally  equipped  Columbia  you  will 
want  to  own  one. 

The  electric  motor,  which  is  a  marvel  of 
silence  and  smoothness,  holds  the  mellow 
but  brilliant  Columbia  tone  absolutely 
true. 

It  operates  perfectly  on  any  standard 
direct  or  alternating  current.  Just  at- 
tach plug  to  socket. 

A  beautiful  Columbia  Electric  Grafo- 
nola  is  just  as  much  a  part  of  the  modern 
home  as  a  beautiful  electric  lamp. 
You  can  purchase  a  Columbia  Electric 
Grafonola  125  E  for  as  little  as  $135. 
The  same  model  equipped  with  Colum- 
bia Individual  Record  Ejector — price 

$145. 

Step  into  any  store  where  Columbia 
Grafonolas  are  sold  and  listen  to  the 
Columbia  Electric  Grafonola.  You  and 
the  Columbia  Electric  Grafonola  will 
quickly  become  friends. 

Columbia  Graphophone  Company 
New  York 


Columbia  Electric 
Grafonola  225  E 
Price  $240 

Cabinet  of  mahogany,  satin 
walnut,  or  quartered  oak  in 
all  finishes,  measuring  49% 
inches  high  on  castors,  and 
22Y2  x  24  inches.  All  ex- 
posed metal  parts  heavily 
plated  in  18  karat  gold. 
Ample  record  storage  room. 


You  benefit  by  mentioning  "The  Electrical  Experimenter"  when  niriting  to  advertisers. 


The  Electrical  Experimenter 

233  FULTON  STREET,  NEW  YORK 
Publisht  by  Experimenter  Publishing  Company,  Inc.  (H.  Gernsback,  President;  S.  Gernsback,  Treasurer;)  233  Fulton  Street,  New  York 


Vol.  V     Whole  No.  56  DECEMBER,  1917  No.  8 


DAYLIGHT  SIGNALING  WITH  SEARCHLIGHT  Front  Cover 

From  a  painting  by  George  Wall 
LOCATING  THE  SUBMARINE  BY  RADIO.. By  H.  Winfield  Secor  509 

ELECTRIC  BOMB  DROPPER  FOR  AEROPLANES   511 

RADIUM  PAINT  IN  THE  WAR   512 

ELECTRIC  XMAS  TOYS   513 


DAYLIGHT  SIGNALING  WITH  ELECTRIC  SEARCHLIGHT...  514 

THE  MARVELS  OF  RADIO-ACTIVITY.    PART  IV  

By  Jerome  S.  Marcus,  B.Sc.  (Ch.E.)  515 

HOW  I  TELEGRAPH  PICTURES  By  J.  H.  Leishman  516 

ELECTRICITY  AND  GOLD  FISHES  By  H.  Gernsback  518 

WOMEN  MAKE  GOOD  RADIO  OPERATORS   519 

A  TRACKLESS  TROLLEY  SYSTEM  By  L.  Schoolcraft  522 

THE  SUBMARINE  AND  KINDRED  PROBLEMS   524 

A  NEW  COMBINED  STEREOSCOPIC  AND  FLUOROSCOPIC 

TABLE    S2S 

MAGNETIC  SEPARATOR  PULLEY  GREAT  TIME  SAVER.... 

By  F.  C.  Perkins  526 

A  REVOLVING  ELECTRIC  XMAS  TREE  By  John  T.  Dwyer  529 


HOW  TO  USE  HIGH  FREQUENCY  CURRENTS  IN  THE  TREAT- 
MENT OF  DISEASE  By  Dr.  Frederick  Finch  Strong  530 

THE  "RADIO  ROLL  OF  HONOR"   533 

SOME  INTERESTING  NEW  RADIO  APPARATUS   534 

THE  AUDION  AND  THE  "EDISON  EFFECT".  .By  George  Holmes  536 
RADIO    TRANSMITTING    INDUCTANCES.      PART    V— THE 

HOW  AND  WHY  OF  RADIO  APPARATUS   537 

THE  UNCROWNING  OF  THE  GIMCRACK  KING  

By  Thomas  Reed  539 

THE  MYSTERIOUS  VOICE  By  C.  A.  Oldroyd  541 

AN  ELECTRICALLY  PLAYED  MANDOLIN— HOW  TO  MAKE 

IT  By  McClure  Albright  542 

AN  AUTOMATIC  STORAGE  BATTERY  CHARGER  


By  Lewis  Scriven  544 

HOW-TO-MAKE-IT  DEPT. — PRIZE  CONTEST   547 

WRINKLES,  RECIPES  AND  FORMULAS. .  Edited  by  S.  Gernsback  549 

EXPERIMENTAL  CHEMISTRY— 19th  Lesson  

By  Albert  W.  Wilsdon  550 

"ELECTRICAL  LABORATORY"— Prize  Contest   551 

LATEST  PATENTS  DIGEST   552 

PHONEY  PATENTS— CONTEST    553 

QUESTION  BOX    554 


SOLAR  "HEAT" 


E  may  take  it  as  an  established  fact  that 
the  sun  is  a  huge  ball  of  incandescent 
matter.  Spectral  analysis  shows  that  the 
sun  contains  every  element  known  to  us 
as  found  on  the  earth.  Every  metal,  every 
gas  is  represented  in  the  incandescent 
photosphere,  i.e.,  the  gaseous  envelope  surrounding  the 
sun,  burning  at  a  tremendous  heat. 

We  know  the  sun  to  be  some  93  million  miles  distant 
from  the  earth.  Enormous  as  this  distance  is — incom- 
prehensible to  the  human  mind— we  receive  daily  from 
our  luminary  a  quantity  of  energy  nothing  short  of 
astounding.  Only  by  remembering  that  a  light-ray 
traveling  at  a  speed  of  close  to  186,000  miles  per  second, 
requires  a  little  over  8  minutes  to  traverse  the  gulf 
separating  the  sun  from  the  earth,  do  we  begin  to 
realize  what  sort  of  a  problem  we  face,  when  we  wish 
to  make  it  clear  to  our  minds  how  such  a  stupendous 
energy,  which  lights  and  heats  our  planet,  is  conveyed 
to  us  thru  a  vacuum.  For  the  odd  93  million  miles 
separating  the  sun  from  the  earth  constitute  of  course 
an  almost  perfect  vacuum.  Nevertheless  the  earth  is 
lighted  and  heated.    But  how  does  it  come  about? 

Now  we  know  that  if  we  go  only  30  miles  above  the 
surface  of  the  earth,  we  strike  a  temperature  of  — 273 
degrees  Centigrade,  the  absolute  zero  of  interstellar  space. 
Nevertheless,  heat  in  some  form  gets  thru  this  tremendous 
cold,  paradoxical  as  this  sounds  at  first.  Otherwise, 
how  do  we  account  for  the  earth  being  heated  by  the 
sun?  If  you  doubt  that  it  gets  colder  as  you  go  up, 
you  have  but  to  climb  a  mountain  of  moderate  height. 
Even  three  miles  up  the  cold  becomes  so  intense  that 
the  top  of  the  mountain  will  be  found  covered  with 
perpetual  ice.  Notwithstanding  this,  we  are  closer  to 
the  sun  by  3  miles  at  the  summit  than  at  the  base  of 
the  mountain!  Also  we  find  by  way  of  further  proof 
that  if  we  expose  a  thermometer  directly  to  the  sun's 
rays  at  the  top  of  the  mountain,  the  temperature  will 
be  about  the  same  as  that  of  the  ice  at  our  feet.  And 
it  makes  little  difference  if  we  perform  this  experi- 
ment on  an  ice  covered  mountain  at  the  equator, 


or  on  a  similar  mountain  in  more  northern  latitudes. 

Logically  then  we  are  forced  to  the  conclusion  that 
we  do  not  receive  heat  rays  from  the  sun  at  all.  For 
the  dark  heat  rays  can  not  pass  thru  a  vacuum.  By 
placing  a  thermometer  in  an  ordinary  Thermos  bottle 
this  statement  can  be  verified  readily. 

But  where  does  the  heat  come  from?  How  is  the 
earth  heated  after  all,  for  heated  it  certainly  is? 

By  the  sun's  light  rays.  We  know  these  rays  not  to 
be  merely  luminous  rays,  but  they  are  in  reality  electro- 
magnetic rays.'  Now  then,  when  these  cold  rays  strike 
the  earth's  atmosphere  at  its  lower  strata,  where  the 
latter  is  heavily  comprest,  to  some  15  lbs.,  per  square 
inch,  these  cold  light  .rays  seem  to  undergo  a  trans- 
formation, and  in  the  act  greatly  heat  the  surrounding 
air.  Just  what  this  transformation  is  we  do  not  as  yet 
know,  mainly  because  we  do  not  actually  know  the  true 
composition  of  a  light  ray.  We  don't  know  what  lies 
beyond  the  ultra  violet,  nor  the  ultra  red  section  of  the 
sun's  spectrum.  Nor  do  we  know  much  of  the  light 
rays'  electrical  structure. 

At  this  point  we  wish  to  make  an  interesting  reflec- 
tion. Not  so  long  ago  the  famous  Dutch  philosopher 
Dr.  Kamerlingh  Onnes  made  certain  experiments  of 
tremendous  import.  He  placed  an  electrical  conductor 
in  an  almost  absolute  zero,  and  found  to  his  astonish- 
ment that  a  current  started  in  such  a  conductor  would 
continue  to  flow  for  19  hours.  The  tremendous  cold  robbed 
the  conductor  of  all  its  former  resistance,  and  the 
electric  current  finding  no  resistance  to  wear  itself  out 
in  heat,  became  a  sort  of  perpetual  circuit,  which  lasted 
as  long  as  the  conductor  was  near  the  absolute  zero. 

Now  the  point  is,  the  space  separating  the  earth  from 
the  sun  is  at  an  absolute  zero.  Is  this  not  perhaps  the 
reason  that  the  sun's  light-rays  which  are  of  course 
electrical  in  nature — act  in  a  like  manner  to  the  elec- 
tric current  in  Dr.  Onnes'  experiments?  This  then 
would  explain,  why  practically  no  energy  is  lost  in  the 
transmission  thru  93  million  miles  of  icy  space. 

H.  Gernsback. 


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507 


508 


THE  ELECTRICAL  EXPERIMENTER 


December,  1917 


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r^|M»i:*^«\:»v!«  *  «,  'O^ai:'!*!.*  '  »  .■  «:l■i;/Wl1■.: 


The* Boy's  Electric  Toys 


There  have  been  other  electrical  experimental  outfits  on  the  market  thus  far,  but  we  do  not  believe 
that  there  has  ever  been  produced  anything  that  comes  anywhere  near  approaching  the  new  experimental 
outfit  which  we  illustrate  herewith. 

"The  Boy's  Electric  Toys"  is  unique  in  the  history  of  electrical  experimental  apparatus,  as  in  the 
small  box  which  we  offer  enough  material  is  contained  TO  MAKE  AND  COMPLETE  OVER 
TWENTY-FIVE  DIFFERENT  ELECTRICAL  APPARATUS  without  any  other  tools,  except  a 

screw-driver  furnished  with  the  outfit.  The  box  construction 
alone  is  quite  novel,  inasmuch  as  every  piece  fits  into  a  special 
compartment,  thereby  inducing  the  young  experimenter  to  be 
neat  and  to  put  the  things  back  from  where  he  took  them.  The 
box  contains  the  following  complete  instruments  and  apparatus 
which  are  already  assembled: 

Student's  chromic  plunge  battery, 
compass-galvanometer,  solenoid,  tele- 
phone receiver,  electric  lamp.  Enoiigh 
various  parts,  wire,  etc.,  are  furnished 
to  make  the  following  apparatus : 

Electromagnet,  electric  cannon,  magnetic 
pictures,  dancing  spiral,  electric  hammer, 
galvanometer,  voltmeter,  hook  for  telephone 
receiver,  condenser,  sensitive  microphone, 
short  distance  wireless  telephone,  test  stor- 
age battery,  shocking  coil,  complete  tele- 
graph set,  electric  riveting  machine,  elec- 
tric buzzer,  dancing  fishes,  singing  tele- 
phone, mysterious  dancing  man,  electric 
jumping  jack,  magnetic  geometric  figures, 
rheostat,  erratic  pendulum,  electric  butter- 
fly, theivmo  electric  motor,  visual  telegraph, 
etc.,  etc. 

This  does  not  by  any  means  exhaust  the  list,  but 
a  great  many  more  apparatus  can  be  built  actually 
and  effectually. 

With  the  instruction  book  which  we  furnish,  one 
hundred  experiments  that  can  be  made  with  this 
outfit  are  listed,  nearly  all  of  these  being  illustrated 
with  superb  illustrations.  We  lay  particular  stress 
on  the  fact  that  no  other  materials,  goods  or  supplies 
are  necessary  to  perform  any  of  the  one  hundred 
experiments  or  to  make  any  of  the  25  apparatus. 
Everything  can  be  constructed  and  accomplished  by 
means  of  this  outfit,  two  hands,  and  a  screw-driver. 
Moreover  this  is  the  only  outfit  on  the  market  to-day 
in  which  there  is  included  a  complete  chromic  acid 
plunge  battery,  with  which  each  and  everyone  of  the 
experiments  can  be  performed.  No  other  source  of 
current  is  necessary. 

Moreover,  the  outfit  has  complete  wooden  bases 
with  drilled  holes  in  their  proper  places,  so  that  all 
you  have  to  do  is  to  mount  the  various  pieces  by 
means  of  the  machine  screws  furnished  with  the  set. 


The  outfit  contains  114  separate  pieces  of  mate- 
rial and  24  pieces  of  finished  articles  ready  to  use 
at  once. 

The  box  alone  is  a  masterpiece  of  work  on  account 
of  its  various  ingenious  compartments,  wherein  every 
piece  of  apparatus  fits. 
Among  the 


finished  mate- 
rial the  follow- 
No.  EX2002  ing    parts  are 

included: 

Chromic  salts  for  battery,  lamp  socket,  bottle  of  mercury,  core  wire  (two  different  lengths),  a 
bottle  of  iron  filings,  three  spools  of  wire,  carbons,  a  quantity  of  machine  screws,  flexible  cord,  two 
wood  bases,  glass  plate,  paraffine  paper,  binding  posts,  screw-driver,  etc.,  etc.  The  instruction  book 
is  so  clear  that  anyone  can  make  the  apparatus  without  trouble,  and  besides  a  section  of  the  instruc- 
tion book  is  taken  up  with  the  fundamentals  of  electricity  to  acquaint  the  layman  with  all  important 
facts  in  electricity  in  a  simple  manner. 

All  instruments  and  all  materials  are  well  finished  and  tested  before  leaving  the  factory. 
We  guarantee  satisfaction. 

We  wish  to  emphasize  the  fact  that  anyone  who  goes  through  the_  various  experiments 
will  become  proficient  in  electricity  and  will  certainly  acquire  an  electrical  education  which 
cannot  be  duplicated  except  bv  frequenting  an  electrical  school  for  some  months. 

The  size  over  all  of  the  outfit  is  14  x  9  x  2H.  Shipping  weight,  8  lbs. 

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■ 

1 


THE,  ELECTRICAL 
EXPERIMENTER 


H.GERN5B&CK  editors' 

H.  W.  5ECPR  EDITOR, 


Vol.  V.   Whole  No.  56 


December,  1917 


4$ 


em 


Number  8 


Locating  The  Submarine  by  Radio 


WHILE  there  have  been  hundreds 
of  schemes  proposed  in  the  past 
few  months,  for  the  detection  and 
destruction  of  submarine  war- 
craft,  there  have  been  but  very 
few  really  practical  suggestions  in  the  total 
number. 

The  present  discussion  deals  with  a  new 
wireless  scheme  for  detecting  the  presence 
of  submarines  as  far  as  two  miles  away 
from  a  given  base,  which  may  be  either  on 


By  H.  WINFIELD  SECOR 

worthless.  At  the  present  time  very  favor- 
able results  are  being  obtained  with  micro- 
phones for  this  purpose,  but  several 
problems  have  yet  to  be  solved  in  order 
that  these  sound-sensitive  devices  will  per- 
form their  functions  under  water  properly 
in  order  to  accurately  spot  the  "Hun"  in 
his  stealthy  U-Boat. 

Among  the  different  forms  of  sub- 
aqueous microphones  devised  by  this  in- 
ventor is  one  mounted  in  a  special  resilient 


taking  place  will  be  gleaned  from  the  ac- 
companying illustration.  A  vessel  is  here 
shown  radiating  a  wireless  wave  of  say 
three  thousand  meters  length,  which  is 
equivalent  roughly  to  two  miles.  Also  for 
the  purpose  of  bringing  out  the  efficiency 
of  the  scheme  more  fully,  two  submarines 
are  shown  and  also  their  effect  upon  the 
radiating  wave  from  the  antenna. 

The  inventor  of  this  means  of  detecting 
enemy  sub-sea    boats,    received    his  first 


HJ)l>IO  DETECTING 
APPARATUS  ON  SHIP 


SUBhAKINE-l ' 


a 


SUBMARINE-  Z 


\    WAVE  DISTORTED 
v  BY  CAPACITY  EFFECT 
OF  SUBMARINE 


This  Radio  Wave  Method  of  Detecting  and  Locating  Submarines  and  Even  "Torpedoes"  Has  Been  Tested  Out  and  Gives  Surprising  Re- 
sults.  It  Is  Effective  up  to  Two  Miles  and  More  and  the  Enemy  Cannot  Evade  Its  Action,  so  Long  as  "Subs"  Are  Made  of  Metal. 


a  ship  or  on  land.  Credit  for  this  submarine 
detector  is  due  to  Mr.  Leon  W.  Bishop, 
who  is  now  associated  with  a  staff  of  ex- 
perts engaged  in  solving  military  and  naval 
problems.  Mr.  Bishop  invented  the  well- 
known  multi-audi-phone  radio  and  tele- 
phone amplifier. 

Mr.  Bishop  has  done  a  great  deal  of  ex- 
perimenting with  microphones  for  the  de- 
tection of  submarines  and  has  evolved  a 
number  of  very  ingenious  and  advanced 
types  of  microphones,  especially  suited  to 
these  requirements,  and  for  which  purpose 
the    ordinary    microphone    is  practically 


substance  so  as  to  keep  it  free  from  or- 
dinary vibrations  and  noises.  Particularly 
has  he  devised  special  circuits  for  using 
microphones  in  this  work  whereby  they 
are  electrically  balanced.  He  is  also  ex- 
perimenting with  microphones  which  pro- 
duce direct  current  pulsations,  thus  con- 
ducing to  the  elimination  of  external 
noises. 

Coming  now  to  the  wireless  scheme  for 
the  detection  of  submarines,  whether  sub- 
merged or  not,  over  ranges  of  two  miles 
and  more,  (depending  upon  the  wave 
length  used),  the  general  idea  of  the  action 

509 


demonstration  of  the  ultra-sensitive  elec- 
trical action  involved  while  operating  an 
undamped  Audion  receiving  set  some 
months  ago,  and  which  effect  is  quite  well 
known. 

It  was  found  that  when  the  Audion 
receptor  was  suitably  tuned,  so  as  to  pro- 
duce a  regenerative  effect,  i.e.,  producing 
radio  frequency  oscillations,  that  at  certain 
times  a  peculiar  sound  effect  could  be 
noticed  in  the  telephone  receivers  connected 
to  the  circuit.  For  sometime  this  change 
in  the  circuit,  as  manifested  by  the  sound 
in  the  telephone  receivers,  remained  an  un- 


510 


THE  ELECTRICAL  EXPERIMENTER 


December,  1917 


ELECTRIC  PLOWING  IN  GER- 
MANY. 

The  German  farmers,  being  very  hard 
prest  in  tilling  large  tracts  of  land  with 
an  heretofore  unknown  shortage  of  labor, 
have  made  extensive  use  of  large  electric 
plows  and  other  agricultural  machines,  one 
of  these  immense 
plows  being  shown 
here. 

Electrically  oper- 
ated agricultural  ma- 
chines of  this  type 
have  been  used  for 
a  number  of  years 
on  German  farms, 
the  electric  light 
companies  distribut- 
ing current  for  the 
purpose  over  very 
extensive  areas,  the 
current  being  trans- 
mitted at  very  high 
potentials,  often  in 
the  neighborhood  of 
70,000  to  100,000 
volts  for  distances 
of  75  to  100  miles 
and  more. 

In  some  cases  cur- 
rent is  supplied  to 
each  individual  ma- 
chine by  means  of 
trolley  poles,  which 
make  contact  with 
trolley  wires  sup- 
ported above  the 
field  under  cultiva- 
tion. In  the  instal- 
lation here  illus- 
trated, current  is 
taken  from  two  trolley  wires  supported  but 
a  short  distance  above  the  ground,  these 
wires  being  moved  along  as  the  plow  starts 
off  on  each  new  run. 

Two  specially  designed  trolley  wheels 
carried  on  an  extension  arm  at  the  side  of 
the  plow  conduct  the  current  from  the  trol- 
ley wires  to  the  electric  motor  on  the  plow. 

The  plow  is  under  perfect  control  of  the 
operator  at  all  times,  and  this  control  is 
effected  thru  the  means  ot  a  drum  con- 


troller, similar  to  those  used  on  trolley  cars 
and  small  electric  locomotives.  These  con- 
trollers, of  which  there  are  two,  can  easily 
be  seen  in  the  photograph  here  reproduced. 

This  particular  machine  possesses  several 
novel  and  unusual  features,  one  of 
which  is  the  fact  that  at  the  end  of  one 


Probably  there  is  no  country  in  the  world 
in  which  vast  numbers  of  gigantic  machines 
have  been  so  extensively  applied  for  cul- 
tivating and  harvesting  crops  as  in  the 
western  part  of  the  United  States,  but  in  the 
application  of  electrically-driven  machines 
for  accomplishing  farm  labors  on  a  titanic 
scale,  the  Teutons 
have  far  out-dis- 
tanced other  coun- 
tries.— Photo  cour- 
tesy Society  for  Elec- 
trical Development. 


The  Teuton  Tillers  of 
Which  Is  lllustra 


the  Soil  Make  Extensive  Use  of  Electrically  Op 
ted  Above.    Current  Is  Supplied  the  Motor  Thru 

run  across  the  field,  during  which  it  cuts 
several  furrows,  the  machine  is  simply  tilt- 
ed up  with  the  main  axle  as  the  center,  and 
the  operator  then  walks  to  the  other  end  of 
the  plow  and  controls  it  on  the  return  run 
from  that  end  of  the  machine.  This  over- 
comes the  problem  of  having  to  turn  the 
cumbersome   machine   around   each  time. 

Two  manual  as  well  as  electrical  con- 
trollers are  provided  for  this  purpose,  one 
set  at  each  end  of  the  plow. 


RADIO  STA- 
TION FOR 
HONGKONG 
OBSERVA- 
TORY. 
A  receiving  in- 
stallation for  the 
radio  station,  Royal 
Observatory,  Hong- 
kong, is  now  being 
constructed.  The 
station  is  located  at 
the  observatory,  in 
latitude  22°  18'  13" 
N.,  longitude  114° 
10'  15"  E.,  of  Green- 
wich. The  installa- 
tion consists  of  a 
single  triangular 
steel-lattice  mast  150 
feet  high.  The  aerial 
(which  is  on  order 
in  America)  will 
spread  from  the 
mast  to  six  chimney 
stacks  of  a  terrace 
of  houses  150  yards 
to  the  south  of  the  mast.  The  receiving 
apparatus  consists  of  a  receiving  set  to  be 
used  in  conjunction  with  a  Brown  relay  and 
high-resistance  telephones. 

At  present  the  installation  is  to  be  used 
only  for  receiving  time  signals  from  Shang- 
hai, Manila,  and  Hanoi,  and  possibly  from 
Tsingtau  and  one  or  more  Japanese  stations 
by  night.  After  the  war  it  is  proposed  to 
install  apparatus  for  distributing  time  sig- 
nals via  Cape  d'Aguilar  radio  station. 


erated  Plows,  One  of 
a  Trolley  Wire. 


solved  problem,  but  by  careful  observation 
it  was  ascertained  that  this  was  due  to  the 
effect  of  a  passing  railroad  train  at  a  dis- 
tance of  about  one  quarter  of  a  mile.  The 
railroad  tracks  did  not  approach  the  build- 
ing in  which  the  wireless  receptor  was 
located,  and  therefore  it  was  decided  upon 
that  the  capacity  effect  of  the  steel  railroad 
train  on  the  wave  radiated  by  the  antenna, 
was  sufficient  to  change  this  wave  in  such 
a  manner  that  the  change  could  be  readily 
noted  in  the  translating  apparatus,  viz.,  the 
telephone  receivers  in  this  case. 

By  looking  at  the  accompanying  illustra- 
tion it  will  be  seen  how  the  presence  of  a 
submarine,  whether  submerged  or  not,  will 
cause  a  reaction  on  the  radiated  wave  from 
an  antenna  located  on  a  ship  or  on  shore. 

Mr.  Bishop  has  actually  tried  this  out 
successfully  over  considerable  distances, 
and  has  found  that  it  is  possible  to  detect 
the  presence  of  not  only  a  submarine  a  mile 
or  so  away,  but  even  the  presence  of  a 
torpedo;  so  ultra-sensitive  is  this  method 
of  locating  a  metallic  body. 

Moreover,  the  direction  in  which  the 
metallic  body  lies  may  be  ascertained  by  the 
use  of  a  directional  antenna,  in  somewhat 
the  same  manner  as  the  wireless  compass 
scheme. 

This   effect   of  bringing  any   form  of 


capacity  in  proximity  to  an  oscillating 
Audion  circuit  is  well-known  to  most  every 
radio  experimenter.  Those  possessing  os- 
cillating Audion  sets  have  found  invariably 
that  all  of  the  circuits  associated  with  this 
device  are  extremely  sensitive  to  such  ef- 
fects. Even  an  approach  of  the  operator's 
body,  or  for  that  matter  his  hand,  toward 
the  apparatus  upsets  the  electro-static 
balance  of  the  circuits.  Some  of  the  sets 
used  have  proven  so  sensitive  in  this  respect 
that  it  became  absolutely  necessary  to  at- 
tach long  insulated  extension  handles, 
sometimes  two  feet  long  to  the  various 
condensers  and  tuning  switches,  so  as  to 
eliminate  as  much  as  possible  this  untoward 
capacity  effect  of  the  body. 

The  accompanying  diagram  showing  con- 
nections of  Audion  oscillator  circuits  as 
well  as  a  third,  or  Audion  detector  circuit, 
suitably  equipt  with  telephone  receivers, 
gives  an  idea  of  the  apparatus  employed  by 
Mr.  Bishop  in  some  of  his  researches  along 
this  line.  Assume  for  instance  an  Audion 
oscillator  with  its  proper  capacity  and  in- 
ductance circuits  all  connected  to  an  an- 
tenna as  shown.  This  causes  the  antenna 
to  radiate  radio-frequency  waves  of  a 
length  depending  upon  the  capacity  and  in- 
ductance in  the  circuit. 

We  may  assume  for  example  that  the 


circuit  is  tuned  to  radiate  a  wave  of  3,000 
meters,  or  roughly  two  miles  wave  length, 
which  gives  a  frequency  of  one  hundred 
thousand  cycles  per  second.  Consider  also 
that  the  second  Audion  oscillator  circuit  is 
set  in  operation  in  inductive  relation  to  the 
first  circuit,  which  is  connected  to  the  an- 
tenna. The  second  or  inductively  associated 
Audion  oscillator  is  tuned  to  the  same 
frequency  or  one  hundred  thousand  per 
second.  Further  we  note  that  there  is  a 
third  coil  inductively  related  to  the  oscil- 
lating circuits  and  which  connects  to  the 
Audion  detector  and  a  pair  of  sensitive 
radio  telephone  receivers. 

Now,  if  a  submarine  lies  within  detect- 
ing range,  say  a  mile  away,  and  the  an- 
tenna is  excited  by  the  Audion  oscillator 
No.  1  with  a  wave  having  a  periodicity  of 
one  hundred  thousand  cycles  per  second, 
then  its  frequency  will  be  slightly  changed 
by  the  capacity  effect  of  the  submarine. 
Suppose  it  causes  the  oscillation  frequency 
of  the  antenna  system  to  change  from 
100,000  cycles  to  101,000  cycles.  If  such 
should  be  the  case,  then  there  will  be  pro- 
duced a  beat  frequency  note  in  the  third 
or  detector  circuit,  having  a  periodicity  of 
one  thousand  cycles  per  second,  which  is  of 
course  an  audible  frequency,  and  therefore 
{Continued  on  page  572) 


BACK  NUMBERS! — Many  readers  desire  to  obtain  back  numbers  of  this  journal.  We  have  a  limited  quantity  of  these  back  issues  on 
hand  and  can  supply  them-at  the  following  rates: — Back  numbers  of  The  Electrical  Experimenter  not  over  three  months  old,  15  cents 
each:  over  three  months  old,  20  cents  each;  over  one  year  old,  35  cents  each. 


December,  1917 


THE  ELECTRICAL  EXPERIMENTER 


511 


New  Electric  Bomb  Dropper  for  Aeroplanes 


BOMB  dropping  from  aeroplanes  can 
only  be  approximately  accurate.  It 
can  be  made  at  least  seventy-five 
per  cent  more  efficient  by  sighting 
and  releasing  the  bomb  by  mechani- 
cal means  and  eliminating  guess-work,  as 
there  is  only  one  aviator  out  of  five  hun- 
dred that  is  really  proficient  in  the  work 
without  some  mechanical  aid.    One  of  the 


slide  is  graduated  into  seconds.  The  avia- 
tor decides  in  what  direction  the  wind  is 
blowing  and  in  order  to  ascertain  the  speed 
at  which  he  is  flying,  he  picks  out  some  ob- 
ject on  the  ground,  having  first  set  his 
slide  at  the  altitude  he  is  flying,  taking  a 
sight  along  the  hypothenuse  formed  by  the 
two  bars  of  the  sight,  and  as  soon  as  the 
object  comes  in  line  he  presses  his  stop 


aviator    to    discern    his    object    at  all. 

A  Yankee  genius,  Mr.  F.  R.  Lewis,  has 
overcome  this  deficiency  by  employing  a 
telescope  mounted  on  a  tripod  or  base, 
swiveled  and  hinged  to  turn  vertically  or 
horizontally,  with  quadrant  and  hand-screw 
to  keep  it  in  the  desired  position  or  angle, 
Figure  2.  It  is  designed  to  have  day  lenses 
made  interchangeable  with  night  lenses,  each 


A  Yankee  Inventor  Has  Perfected  the  Simple  Electric  Bomb  Dropper  Here  Illustrated  for  Use  on  Aircraft.  The  Aviator  Checks  up  His 
Actual  Flying  Speed,  Sets  His  Range-finding  Telescope  and  Flies   Over  the  Target.     At  the   Proper  Moment  the  Automatic  Electric 

Clock  Switch  Releases  the  Bomb. 


best  bomb  sights  in  use  by  the  Allies  is  the 
C.  F.  S.  (Central  Flying  School)  in  the 
British  service.  The  sighting  is  done  over 
two  bars  arranged  vertically,  one  above 
the  other,  about  six  inches  apart.  The  third 
is  fixt  in  a  slide,  level  with  the  upper  sight, 
thus  forming  a  right  angle  triangle,  with 
the  right  angle  forward  and  upward.  The 


watch,  keeping  the  sight  all  the  time  on  the 
object  he  has  selected,  until  it  comes  in  line 
with  the  two  vertical  bars  of  the  sight. 
He  then  reads  the  time  on  his  watch  and 
adjusts  his  index  slide  to  read  that  time. 

But  the  great  difficulty  with  this  sight 
is  that  at  a  high  altitude,  or  at  night,  it  is 
very  difficult  or  nearly  impossible  for  the 


provided  with  cross-hairs,  and  external  lo- 
cating sights,  Figure  3,  as  it  is  very  difficult 
to  focus  an  object  on  the  cross-hairs  of 
the  telescope,  even  when  flying  at  sixty 
miles  an  hour,  until  after  the  object  is  lo- 
cated. 

(Continued  on  page  754) 


512 


THE  ELECTRICAL  EXPERIMENTER 


December,  1917 


RadiumiPaint  in  the  War 


THE  persistent  electrical  activity  of 
radium,  especially  when  used  in  com- 
bination with  zinc  sulfid,  which  gives 
rise  to  a  luminous  effect  which  is 
readily  noticeable  in  the  dark,  has 
led  to  the  adoption  of  this  peculiar  mixture 
for  many  different  uses  in  the  great  world 
war.  A  large  English  concern  has  been 
extremely  busy  of  late  turning  out  these 
"luminous  paint"  articles  for  use  by  the 
soldiers  and  sailors  of  His  Majestv  the 
King. 


enemies  in  the  dark  by  the  second  line  of 
men  who  follow. 

The  illustration,  Fig.  2,  shows  a  most 
useful  beacon  provided  with  a  spike  to  be 
driven  in  the  ground.  They  are  also  made 
in  the  shape  of  large  buttons,  the  luminous 
painted  top  being  covered  with  transparent 
celluloid,  and  surmounted  on  a  small  steel 
spike  jHs-inch  long,  which,  by  pushing,  en- 
ters into  any  woodwork,  and  when  affixt  to 
the  top  of  short  stakes  driven  into  the 
ground  and  placed  10  yards  apart,  afford  a 


Radium  Paint  Is  Finding  Many  Diversified  Applications  in  the  World  War.     In  the  Form 
of  "Beacons"  It  Guides  the  Stretcher- Bearers  Thru  "No-Man's"  Land  and  Enables  Sig- 
naling to  Be  Carried  on  Safely  in  the  Front-Line  Trenches. 


Over  100,000  marching  compasses  are  in 
ilaily  use  by  the  allied  armies,  each  fitted 
vith  a  luminous  radium  dial  readable  at 
any  time,  even  on  the  darkest  night.  Aero- 
planes skim  along  thru  the  night,  the  avia- 
tors guided  by  radium  be-dialed  compasses. 
At  sea,  the  doughty  little  "sub"  destroyers 
shoot  hither  and  thither  with  never  a  light 
to  be  seen — the  radium  lighted  compass  dial 
answers  the  question.  The  man  using  it 
can  see  the  dial  all  the  time,  but  you  cannot. 
Fig.  1  illustrates  a  clever  use  for  "luminous 
paint"  collars.  These  linen  tabs  present  a 
luminous  surface  of  10  square  inches,  and 
are  for  attachment  to  the  back  of  the  tunic, 
so  that  when  the  first  line  of  men  go  over 
the  top,   they  will   not  be  mistaken  for 


guide  to  relief  parties  going  and  returning 
in  the  dark.  One  hundred  of  these  10  yards 
apart  will  serve  1.000  yards,  the  stakes  be- 
ing placed  in  the  day  on  chosen  fairly  level 
ground. 

One  of  the  most  useful  articles  for  dark 
night  operations  is  "luminous  tape."  This 
tape,  if  placed  on  the  ground  and  secured 
by  stakes,  metal  rods  or  stones,  is  prevented 
from  being  shifted  by  the  wind.  The  "tape 
layer"  places  the  tape  in  position  during  the 
day,  choosing  a  safe  path  across  the  coun- 
try, and  diverting  from  the  straight  path 
according  to  the  condition  of  the  ground. 
The  path  should  be  wide  enough  for  men  to 
march  four  abreast  up  one  side  of  the  tape 
and  returning  the  other  side,  say,  in  all 


about  12  feet  wide.  Where  this  is  not  pos- 
sible the  tape  layer  makes  a  break  in  the 
tape  every  few  yards,  and  starts  again  con- 
tinuously when  the  path  is  wider.  Any 
obstacle  in  the  way,  such  as  a  tree  or  post, 
could  have  a  small  length  of  tape  tied 
around  it  (see  Fig.  3). 

Should  a  ditch  come  across  the  path  he 
would  lay  short  pieces  of  the  tape  at  right 
angles  on  either  side  of  the  ditch.  In  case 
of  the  ditch  being  over  4  feet  deep,  the 
man  should  have  a  luminous  beacon  with 
him  and  write  on  it  the  depth  of  the  ditch, 
also  the  width,  with  a  special  pencil,  and 
place  it  by  the  tape,  when  near  the  ditch. 

It  is  readily  possible  to  form  large  let- 
ters out  of  this  tape  by  nailing  it  up  with 
zinc  nails.  Such  signs  as  "Fireman,"  "Doc- 
tor," etc.,  also  direction  arrows  prove  ex- 
tremely serviceable,  see  Fig.  3. 

The  luminious  tape  is  also  very  useful 
for  the  work  of  the  medical  corps — the 
tape-layer  by  daylight  choosing  fairly  level 
ground  to  guide  the  stretcher  bearers — thus 
saving  their  labor  in  the  dark,  with  less 
jolting  to  the  wounded.  Moreover,  lamps 
afford  a  mark  for  the  enemy — whereas  the 
tape  can  only  be  seen  by  those  immediately 
over  it — 'enabling  work  to  be  done  silently 
in  the  dark,  the  darker  the  better. 

Signaling  in  the  front  line  trenches  at 
night  is  always  a  precarious  undertaking. 
Luminous  paint  beacons  have  been  used 
very  successfully  for  signaling  silently  by 
night.  They  are  specially  useful  in  trenches 
which  are  in  close  proximity  to  the  enemy, 
saving  the  need  of  whispering  the  words 
of  command,  which  causes  a  hushing  sound, 
when  complete  silence  is  required  for  lis- 
tening to  the  enemies'  movements.  These 
luminous  beacons  will  carry  a  message  a 
distance  of  20  yards  or  60  feet;  sufficient 
for  all  average  requirements.  The  signal- 
ing can  be  either  done  with  the  Morse  code 
or  by  describing  large  capital  letters  of 
the  alphabet  the  reverse  way,  and  by  the 
hand  waving  them  in  the  air.  The  Royal 
Engineers  of  the  English  army  are  said  to 
have  been  the  first  to  use  these  novel,  yet 
wonderful  signaling  devices. 


TO    TELEGRAPH     PHOTOS  BE- 
TWEEN   BERLIN    AND  CON- 
STANTINOPLE   BY  KORN 
SYSTEM. 

It  is  reported  that  Dr.  Korn,  the  eminent 
German  scientist,  proposes  to  introduce  his 
system  for  the  telegraphic  transmission  of 
pictures  on  the  Berlin-Vienna-Sophia-Con- 
stantinople-Bagdad route. 

For  this  purpose  either  telegraphic  or 
telephonic  connections  can  be  utilized.  So 
far  as  telephone  connections  are  concerned, 
one  could  conceive  stations  at  Vienna  and 
Budapest  in  connection  with  Berlin,  the 
lines  being  occupied  for  a  quarter  of  an 
hour  only.  In  these  circumstances  pictures 
of  an  event  taking  place  in  the  afternoon 
could  appear  the  next  day  in  the  Vienna 
journals.  Transmission  for  longer  dis- 
tances, such  as  from  Berlin  to  Constanti- 
nople, would  involve  the  use  of  telegraphic 
lines,  which  would  enable  an  ordinary  pho- 
tograph to  be  transmitted  in  about  an  hour. 
The  chief  expense  involved  is  the  occupa- 
tion of  telegraph  and  telephone  lines  be- 
tween such  distances,  but  it  is  thought  that 
the  governments  of  the  four  countries  con- 
cerned might  grant  very  moderate  rates  if 
the  lines  were  only  used  during  hours  when 
there  is  little  or  no  traffic. 


December,  1917 


THE  ELECTRICAL  EXPERIMENTER 

ELECTRIC  XMAS  TOYS 


513 


514 


THE  ELECTRICAL  EXPERIMENTER 


December,  1917 


Daylight  Signaling  With  Electric  Searchlight 


WHILE  the  electric  searchlight  is 
used  very  often  for  signaling 
purposes  at  night,  by  means  of  a 
suitable  shutter  device,  enabling 
the  operator  to  send  out  short  and 
long  flashes  of  light  corresponding  to  the 
signals  of  the  telegraphic  code,  it  seems 
somewhat  paradoxical  to  think  of  signaling 
in  broad  daylight  with  a  small  electric 
searchlight. 

Such  is  the  case,  however,  as  the  accom- 
panying photograph  tends  to  corroborate, 
this  particular  illustration  show- 
ing a  member  of   the  French 
Signal  Corps  in  the  act  of  signal- 
ing to  an  aeroplane  in  flight. 

While  very  efficient  wireless 
communication  apparatus  have 
been  developed  for  aircraft  re- 
quirements, the  range  is  some- 
what limited  under  certain  con- 
ditions, and  this  improved 
scheme  of  signaling  in  daytime 
as  well  as  night,  for  carrying  on 
communication  between  two  or 
more  aeroplanes  or  between  an 
aeroplane  and  the  ground,  comes 
as  a  very  welcome  auxiliary  to 
the  aforesaid  means  of  signaling 
gun  ranges,  etc. 

As  our  front  cover  illustration 
shows,  as  well  as  the  accompany- 
ing official  photograph,  the 
miniature  searchlight  used  for 
carrying  on  communication  by 
means  of  short  and  long  flashes 
of  light  corresponding  to  the 
dots  and  dashes  of  the  tele- 
graphic code,  is  a  very  simple 
affair,  and  not  as  cumbersome  as 
might  be  imagined  off  hand. 
When  the  searchlight  is  to  be 
used,  it  is  held  in  the  hands  of 
the  operator  in  such  a  manner 
that  it  will  bring  the  telescope 
into  sighting  position,  the  tele- 
scope member  being  attached  to 
the  top  of  the  searchlight  frame. 
The  operator  then  aims  the 
searchlight  at  the  aeroplane  with 
which  communication  is  to  be 
establisht  and  maintained.  He 
then  transmits  the  message  by 
means  of  a  telegraph  key  mounted 
on  the  side  of  the  searchlight. 

In  this  way,  long  and  short 
flashes  of  light  are  sent  out, 
spelling  out  the  desired  words  or 
numerals  in  the  telegraphic  code. 
The  telescope  enables  the  oper- 
ator to  see  the  distant  flashes  of 
the  answering  light  beam  from 
the  aeroplane,  and  thus  it  be- 
comes possible  to  carry  on  com- 
munication both  ways. 

The  searchlight  is  operated 
from  a  portable  storage  battery, 
contained  in  the  carrying  case,  shown  in  the 
illustration,  the  case  being  provided  with 
suitable  rheostat  and  control  switches,  so 
that  the  light  may  be  burnt  constantly  at 
the  highest  efficiency. 

The  entire  outfit,  altho  it  has  a  range 
of  10,000  feet  or  approximately  two  miles 
in  broad  daylight,  and  about  twice  this 
range  at  night,  is  very  light  in  weight.  It 
might  be  imagined  that  such  a  beam  of  light 
used  for  important  and  secret  communica- 
tion with  a  signal  corps  post  on  land,  might 


be  intercepted  by  the  enemy,  but  such  is 
not  the  case,  and  besides  if  such  a  state  of 
affairs  should  happen  to  occur,  it  is  quite 
possible  that  the  enemy  would  not  gain 
much  valuable  information.  This  is  so  for 
the  reason  that  these  messages  are  sent 
in  a  special  cipher,  and  moreover  the  make- 
up of  the  code  is  changed  frequently. 

In  order  that  the  aviator  may  know 
where  to  look  for  these  visual  signals,  the 
land  operator  is  stationed  near  a  sort  of 
tent,  made  of  four  brightly  colored  cloth 


GRAVITY  REVERSED. 

Absolute  proof  that  the  gravitational  at- 
traction between  masses  of  matter  varies 
with  changes  in  their  electrical  potential 
due  to  electrical  charges  upon  them  has 
been  obtained  by  Dr.  Francis  E.  Nipher  in 
a  whole  year  of  experiments  in  the  private 
laboratory  of  Washington  University,  St. 
Louis,  financially  backed  by  the  Carnegie 
Institution. 

Dr.  Nipher  is  one  of  the  greatest 
authorities  in  the  world  on  electrical  meas- 
urements and  the  nature  of  electric  cur- 
rents. 

He  suspended  two  spheres  of 
lead,  one  inch  in  diameter,  from 
silk  fibres  about  5  feet  8  inches 
long  inside  an  insulating  screen 
specially  constructed  of  wood, 
metal,  cardboard,  wax  and  glass, 
with  a  layer  of  air  in  the  middle, 
and  cut  off  radiation  from  the 
sky  and  all  changes  in  tem- 
perature. Spheres  of  lead  ten 
inches  in  diameter  were  adjust- 
ably mounted  below  and  a  tele- 
scope was  set  to  peer  thru  a 
slit  in  the  screen,  opposite  to  a 
specially  designed  scale. 

An  influence  machine,  driven 
by  a  single  phase  motor,  was 
used  for  varying  the  electrical 
potential  in  the  lead  spheres. 

Dr.  Nipher  not  only  dimin- 
ished the  gravitational  attrac- 
tion by  charges  of  electricity 
upon  the  large  spheres,  but  he 
reduced  it  to  zero  and  then 
turned  it  into  repulsion.  He  was 
able  to  measure  this  repulsion, 
and  at  times  it  reached  a  de- 
crease of  250  per  cent  in  the 
normal  value  of  the  gravita- 
tional attraction. 


Photo  ©  By  International  Film  Service 


The  French  Army  Has  Recently  Perfected  a  Miniature  Searchlight 
and  Telescope  for  Signaling  To  and  From  Aircraft  in  Daylight,  as 
Well  as  at  Night.    It  Has  a  Range  of  Two  Miles  in  Broad  Daylight. 


/hich 


strips,  as  portrayed  graphically  on  our  front 
cover.  From  above,  these  strips  appear  as 
a  bright  cross,  visible  from  a  great  height. 
Below,  on  the  ground  is  placed  another 
piece  of  cloth  showing  the  aeroplane  in- 
signia, in  this  case  the  newly  adopted  red 
central  spot  on  a  white  field,  surrounded 
by  a  blue  star — the  American  colors. 


The  winds  at  Curacao  are  so  steady  that 
three  wireless  stations  depend  upon  wind 
mills  for  power. 


HIST!  GERMAN  RADIO 
SPIES. 

The  wireless  operator  at  divi- 
sion headquarters  at  one  of  the 
National  Army  camps  got  a 
shock  recently  that  will  not  be 
duplicated  until  the  troops  start 
"over  the  top." 

He  was  playing  idly  with  the 
condensers  of  his  apparatus  try- 
ing to  pick  up  a  word  or  two 
from  Arlington  or  Honolulu  and 
not  getting  much  when  the  re- 
ceivers began  to  crack : 

"C-Q"  came  the  ■  general  call. 
"C-Q"-"C-Q." 

And  the  character  of  the  spark 
showed  that  the  sending  instru- 
ment was  close  at  hand.  All  the 
sleuths  of  the  signal  corps  pre- 
pared to  chase  this  interloper  to 
his  lair. 

He  began  to  have  visions  of 
illegal  plants  hidden  in  the  bayous  of  the 
gulf  coast — of  spies  carrying  on  their  work 
under  the  very  fence  of  the  camp. 

"Who  are  you?"  he  flashed  at  once.  "By 
what  right  are  you  operating  a  radio?" 

It's  hard  luck  to  spoil  a  thrilling  story 
like  this,  but  right  here  the  whole  plot  blew 
up. 

"I'm  Jones,"  came  the  answer  at  a  rate 
of  about  20  words  a  minute.  "I'm  Jones, 
sending  from  the  124th  field  artillery — use 
of  set  approved  by  Lieutenant-Colonel  H. 
B.  Hackett.    Nice  evening,  isn't  ft?" 


DATE  OF  ISSUE. — As  many  of  our  readers  have  recently  become  unduly  agitated  as  to  when  they  could  obtain  The  Electrical 
Experimenter,  we  wish  to  state  that  the  newsstands  have  the  journal  on  sale  between  the  twelfth  and  the  eighteenth  of  the  month  in 
the  eastern  part  of  the  United  States  and  about  the  twentieth  of  the  month  west  of  the  Mississippi  River.  Our  subscribers  should  be  in 
possession  of  their  copies  at  these  dates.  Kindly  bear  in  mind,  however,  that  publications  are  not  handled  with  the  same  dispatch  by  the 
Post  Office  as  a  letter.  For  this  reason  delays  are  frequent;  therefore  kindly  be  patient  and  do  not  send  us  complaints  as  to  non-arrival 
of  your  copy  before  the  twenty-fifth  of  the  month. 


December,  1917 


THE  ELECTRICAL  EXPERIMENTER 


515 


The  Marvels  of  Radio-Activity 


Heat  Emission  of  Radio-Active  Matter. 

IN  1903,  it  was  shown  by  Curie  and 
Laborde  that  a  radium  compound  was 
always  hotter  than  the  surrounding  air 
and  radiated  heat  at  a  constant  rate  of 
118  gram  calories  per  hour  per  gram 
of  radium.  This  means  that  a  gram  of 
radium,  or  0.0028  pound,  will  boil  about 
0.0045  pound  of  water  every  hour.  Enough 
radium  properly  contained,  would  run  a 
boiler  continuously  with  only  the  addition 
of  water.  There  is  now  no  doubt  that  the 
evolution  of  heat  by  radium,  and  other 
radio-active  substances,  is  a  secondary 
phenomenon  resulting  mainly  from  the  ex- 
pulsion of  alpha  particles.  Since  the  latter 
have  a  large  kinetic  energy  due  to  their 
high  velocity,  and  are  easily  stopt  by  matter, 
they  are  absorbed  by  the  radium  itself  or 
its  immediate  container,  and  the  energy  of 
motion  is  converted  into  heat.  From  this, 
the  evolution  of  heat  is  proportional  to  the 
time  and  number  of  alpha  particles  ex- 
pelled, as  the  kinetic  energy  transformed  is 
in  turn  dependent  on  the  expelled  particles. 
Rutherford  and  Barnes  first  confirmed  this 
view  by  their  experiments.  They  showed 
that  emanation  and  the  following  products 
were  responsible  for  about  three-fourths 
of  the  heat  evolved  by  radium  in  equili- 
brium. 

The  heating  effect  decays  with  the  activity, 
as  observed  in  studies  of  emanation.  The 
products  radium  A,  and  radium  C,  each 
have  a  heating  effect  proportional  to  their 
activity.  Measurements  of  the  heating  ef- 
fect of  thorium,  uranium,  pitchblende,  and 
polonium  have  been  made,  the  evolution  of 
heat  being  in  each  case  proportional  to  the 
kinetic  energy  of  the  alpha  particles. 

An  enormous  amount  of  energy  accom- 
panies the  transformation  of  radio-active 
matter  where  alpha  particles  are  emitted. 
It  must  be  remembered  that  these  particles 
are  themselves  matter,  as  was  said  before, 
and  hence  have  energy  when  traveling  at 
a  high  rate  of  speed,  just  as  does  a  thrown 
baseball,  for  example,  the  emanation  from 
one  gram  of  radium  in  equilibrium,  with 
its  products,  emits  heat  initially  at  the  rate 
of  90  gram  calories  per  hour.  The  total 
heat  emitted  during  its  transformation  is 
about  12,000  gram  calories,  enough  heat  to 
change  0.12  pound  of  ice  into  steam.  Since 
the  initial  volume  of  the  emanation  from 
one  gram  of  radium  is  0.06  cubic  centi- 
meters, one  cubic  centimeter  of  emanation 
will  emit  during  its  lifetime  20,000,000  gram 
calories  of  heat.  Now  taking  the  atomic 
weight  of  the  emanation  as  222,  one  gram, 
or  0.0022  pound,  of  radium  emanation  will 


Fig.    2. — Apparatus    Used    in  Producing 
Helium   from    Radium    Emanation.  The 
Alpha   Rays  Pass  Thru  the  Thin  Glass 
Inner  Wall  and  Produce  Helium. 


give  off  2,000,000,000  gram  calories  of  heat. 

Let  us  assume  a  boiler  that  evaporates 
100  pounds  of  water  per  hour  at  normal 
boiling  point  and  atmospheric  pressure,  the 
temperature  of  the  water  to  be  15°  C,  or 
60°  F.  Then,  neglecting  the  absorption  of 
heat  by  the  boiler  itself,  the  heat  necessary 


By  JEROME  S.  MARCUS,  B.Sc.  (Ch.  E.) 

PART  IV.  (Conclusion.) 

per  hour  will  be  lOOx  (100—15)  xlOOO/2.2. 
ar  3,863,000  gram  calories  ( 1000  grams  equals 
2.2  pounds,  and  100—15  or  85°  is  the  rise  in 
temperature).  Then  dividing  2,000,000,000 
by  3,863,000  we  have  516.7.  So  one  gram 
of  radium  emanation  will,  by  decaying,  give 
off  enough  heat  to  run  such  a  boiler  516.7 
hours  continuously,  evaporating  51,670 
pounds  of  water.    (See  Fig.  1.) 

This  evolution  of  heat  is  really  enormous 
compared  with  that  emitted  by  any  known 
chemical  reaction.  And  there  is  every 
reason  to  believe  that  the  total  evolution  of 
energy  from  any  type  of  radio-active  matter 
during  transformation  is  of  similar  propor- 
tions to  that  of  the  radium. emanation.  The 
atoms  of  matter  must  consequently  be 
regarded  as  containing  enormous  stores  of 
energy,  which  are  released  by  the  disinteg- 
ration of  the  atom.  Investigations  along 
the  lines  of  the  electronic  theory  of  atomic 
structure  bear  out  this  view.* 

Production  of  Helium 

In  1902  Rutherford  and  Soddy  suggested 
that  the  helium  which  is  invariably  found 
accompanying  radio-active  minerals  was 
derived  from  the  breaking  up  of  the  radio- 
active matter.  A  year  later  Ramsay  and 
Soddy,  in  their  famous  researches  which 
recalled  to  us  thru  newspaper  comment  the 
old  alchemy,  definitely  showed  that  helium, 
a  gas  we  consider  as  an  individual  element, 
was  produced  by  radium  and  also  by  its 
emanation.  The  presence  of  helium  in  the 
atmosphere  of  the  sun  is  one  of  the  argu- 
ments for  radio-active  matter  in  the  body 
of  the  sun  itself.  It  seemed  very  probable, 
that  from  its  observed  mass,  the  alpha  par- 
ticle was  an  atom  of  helium.  This  was 
proven  by  the  work  of  Rutherford  and 
Geiger  who  showed  the  alpha  particle  to  be 
an  atom  of  helium,  carrying  two  unit 
charges  of  electricity.  Hence,  a  form  of 
transmutation  of  matter  according  to  our 
general  theories  of  chemistry  has  really 
taken  place. 

In  order  to  prove  this  definitely,  it  was 
necessary  to  show  that  the  alpha  particles 
themselves  give  rise  to  helium.  Rutherford 
and  Rayes  did  this  by  allowing  the  alpha 
rays  from  a  large  amount  of  emanation  to 
pass  thru  the  very  thin  glass  walls  of  the 
containing  tube.  The  collected  particles 
gave  the  spectrum  of  helium,  proving  them 
to  be  indubitably  helium  atoms.    (Fig.  2.) 

Hence,  all  radio-active  matter  expelling 
alpha  particles  gives  rise  to  helium.  The 
rate  of  production  of  helium  as  calculated 
by  Rutherford  and  Geiger,  who  counted  the 
particles  and  measured  their  charge,  should 
be  158  cubic  millimeters  per  year.  Think 
of  working  with  a  quantity  sp  small !  A 
close  agreement  is  shown  by  the  observa- 
tions of  Boltwood  and  Rutherford,  who 
found  the  production  to  be  163  cubic  milli- 
meters per  year. 

Products  of  Radium 

The  successive  transformations  of  radium 
were  shown  in  the  table  in  the  last  article 
(part  III)  of  this  series.  When  a  wire 
charged  negatively  has  been  exposed  for 
some  time  to  radium  emanation  it  becomes 
coated  with  a  thin  film  of  radium  A,  B,  and 
C.  About  twenty  minutes  after  the  removal 
of  the  wire  from  the  emanation,  radium  A 


has  practically  disappeared  and  the  rays 
arise  entirely  from  radium  C.  This  has 
proven  of  great  value  in  measurements,  as 
radium  C  is  a  source  of  an  intense  homo- 
geneous alpha  radiation.  The  wire,  how- 
ever, still  shows  a  residual  activity,  very 


1    /  Qrom 

nf  P.mnnnfinn  will  1 

evaporate  simo  pounds  of  .  /7~^H 
water             •,                 I M ' 

iiimimiiiil/ltfii 

.  e 

Radium 
boiler 

m 

i 

f'9-i 

© 

*  A  few  years  ago,  H.  G.  Wells,  in  a  story  ap- 
pearing in  The  Century  Magazine,  used  this  en- 
ergy as  a  weapon  in  the  world  war  which  he 
predicted.     The  story  is  really  fascinating. 


Fig.    1. — A    Theoretical    Radium  Boiler. 
One   Gram    of    Radium    Emanation  Will 
Evaporate  51,670  Pounds  of  Water,  Befor* 
It    Becomes  Exhausted. 


small  and  reaching  a  maximum  in  about 
three  years.  The  slow  change,  of  course, 
consists  in  the  successive  transformations 
in  the  series. 

Radium  D  is  rayless,  and  of  a  calculated 
period  of  17  years.  It  was  at  first  thought 
that  radium  E  was  complex,  but  no  special 
evidence  has  been  observed.  Radium  F  is 
identical  with  polonium,  the  first  active 
material  separated  by  Mme.  Curie.  Sim- 
ilarly, radium  D  is  the  source  of  activity 
in  "Radio-lead." 

It  is  interesting  to  note  the  valuable 
results  acquired  from  the  observation  of  the 
extremely  minute  residual  deposits  from 
emanation. 

Radium  Emanation 

The  radium  emanation  has  been  purified 
by  condensing  it  in  liquid  air,  and  then 
pumping  off  the  residual  gases.  In  a  pure 
state  the  emanation  is,  weight  for  weight, 
100,000  times  as  active  as  pure  radium. 
Pure  emanation  in  a  spectrum  tube  gives 
characteristic  bright  lines.  The  electrical 
discharge  in  the  gas  (Geissler  tube  action) 
is  of  a  bluish  color,  continued  sparking 
driving  the  emanation  into  the  tube  walls 
and  electrodes.  Even  with  the  minute 
quantities  obtainable,  the  boiling  point  has 
been  determined  as  71°  C.  When  first  con- 
densed, liquid  emanation  is  colorless,  at 
lower  temperatures  it  freezes,  while  at  the 
temperature  of  liquid  air  it  has  a  bright 
rose-colored  glow.  The  density  of  liquid 
emanation  is  about  5.5. 

The  emanation  has  definite  chemical 
properties,  and  belongs  to  the  group  of 
monatomic  inert  gases,  with  argon,  helium, 
etc.  It  is  somewhat  soluble  in  water,  and 
readily  absorbed  by  charcoal. 

A  large  amount  of  work  has  been  done 
in  measuring  the  amount  of  thorium  and 
radium  emanation  in  the  atmosphere,  and 
in  determining  the  quantity  of  radium  and 
thorium  in  the  earth's  surface.  Important 
theories  regarding  atmospheric  electricity 
(the  aurora  borealis,  etc.)  and  bearing  on 
geology  are  based  on  this  work. 

Origin  of  Radium 

Radium    is    separated    from    the  two 
uranium  minerals,  pitchblende  and  carnotite, 
the  former  coming  from  Austria,  and  the 
(Continued  on  page  572) 


516 


THE  ELECTRICAL  EXPERIMENTER 


December,  1917 


How  I  Telegraph  Pictures 


THE      ELECTRICAL  EXPERI- 
MENTER has  asked  me  to  explain 
to  its  readers  my  system  for  the 
transmission  of  pictures  by  electricity 
— i.e.,  Telegraphing  pictures.  The 
actual  workings  of  the  instruments  have 
never  before  been  explained  in  detail  to  the 
readers  of  any  periodical. 
The  idea  of  telegraphing  pictures  is  not 


way.  I  perceived  immediately  that  a  picture 
composed  all  of  black  and  white  could  be 
made  to  make  and  break  a  current  by  form- 
ing the  black  or  white  on  an  insulating 
material  upon  a  metal  plate  and  causing  a 
current  to  pass  from  the  plate  to  a  tracing 
needle,  so  that  the  insulating  parts  would 
break  the  said  current. 


Photograph  of  President  Wilson  As  Re- 
produced At  Distant  End  of  Telegraph 
Circuit    By    Mr.    Leishman's  Recently 
Perfected  Apparatus. 


new ;  in  fact,  a  scheme  for  accomplishing 
this  was  suggested  fully  seventy  years  ago. 
Of  recent  years,  most  experimenters  that 
have  entered  this  field  have  made  use  of  the 
peculiar  property  of  selenium  for  changing 
its  electrical  resistance  when  exposed  to 
light.  My  system  is  far  less  complicated 
and  expensive  than  those  using  selenium, 
and  it  is  possible  by  its  use  to  receive  a 
very  clear  and  distinct  picture  at  almost 
twice  the  speed  heretofore  obtainable.  It 
is  needless  to  say  that  I  make  use  of  prin- 
ciples entirely  different  from 
those  upon  which  other  ma- 
chines are  based.  This  is  due 
to  the  fact  that  I  entered  this 
field  entirely  ignorant  of  any 
other  single  wire  system,  my 
entire  attention  having  pre- 
viously been  given  to  certain 
mathematical  instruments. 

In  order  to  make  this  dis- 
cussion within  the  under- 
standing of  all,  I  shall  avoid 
all  technical  language  and 
make  the  explanation  as  sim- 
ple as  possible.  Let  it  first  be 
understood  that  the  telegraph- 
ing of  pictures  is  not  tele- 
vision ;  it  does  not  make  it 
possible  to  see  the  person  to 
whom  you  are  telephoning,  as 
that  would  necessitate  the 
transmission  of  moving  pic- 
tures, or  about  seventeen  pic- 
tures per  second.  At  the 
present  time,  such  a  thing  is 
impossible  for  both  electrical 
and  mechanical  reasons.  It 
is  possible,  however,  to  send 
and  receive  one  picture  in  a  very  few  min- 
utes. Some  people  ask  what  would  happen 
should  the  picture  collide  with  a  building. 
This,  as  readers  of  The  Electrical  Experi- 
menter probably  know,  cannot  happen  be- 


cause the  actual  picture  being  transmitted 
remains  at  the  sending  machine,  a  reproduc- 
tion being  effected  at  the  receiving  end  by 
the  building  up  of  minute  portions,  one  at  a 
time,  until  the  entire  picture  is  received. 

The  telegraphing  of  pictures  therefore 
resolves  itself  into  the  following  distinct 
elements :  A  means  for  gradually  covering 
the  entire  surface  of  the  picture  by  some 
device  capable  of  translating  the  light  and 
the  shade  of  the  picture  into  pulsations  or 
variations  of  an  electrical  current ;  and  a 
means  for  successively  recording  these  pul- 
sations or  variations  in  the  form  of  what 
appears  to  be  graduations  of  light  and 
shade. 

How  I  accomplish  these  things  can  best 
be  shown  by  first  explaining  how  the  tiny 
parts  of  the  picture  are  successively  trans- 
mitted and  recorded.  Obviously,  this  can 
best  be  done  by  an  arrangement  similar  to 
a  cylinder  phonograph  or  dictating  machine, 
both  the  sending  and  receiving  instruments 
using  this  mechanism.  The  carriage  that 
is  sending  or  receiving,  gradually  progresses 
from  one  end  of  the  cylinder  to  the  other 
on  a  spiral  or  screw,  and  the  picture  itself 
rotates  on  the  cylinder.  This  makes  it  pos- 
sible for  all  parts  of  the  picture  to  be 
covered  in  the  same  succession  at  both  ends 
of  the  line.  The  cylinders  must  of  course 
revolve  in  exact  synchronism  to  prevent 
distortion,  but  for  the  sake  of  clearness 
this  will  be  explained  later. 

The  next  problem  is  that  of  causing 
light  and  shade  to  affect  the  passage  of 
an  electrical  current.  This,  of  course,  prop- 
erly constitutes  the  sending  device.  As 
previously  stated,  some  systems  vary  an 
electrical  current  by  causing  the  light  and 
shade  of  the  picture  to  act  upon  a  portion 
of  selenium  thru  which  the  current  passes. 
This  is  a  very  direct  way  of  solving  the 


Mr.  Leishman  and  His  Machine  For  Telegraphing  Pictures,  Photos, 
Script,  Etc.,  Over  Telegraph  Or  Telephone  Lines. 


problem,  because  there  must  be  an  "eye" 
that  recognizes  light  and  shade  and  that 
will  vary  an  electrical  current  accordingly. 
It  is  possible,  however,  to  accomplish  this 
in  an  easier,  cheaper  and  less  complicated 


Another  Sample  of  the  Work  Which  the 
Leishman    Machine  Will    Reproduce  In 
a  Few  Minutes  Over  Existing  Telegraph 
Circuits. 


This  idea  then  had  to  be  elaborated  upon 
to  permit  the  transmission  of  a  half-tone. 
All  newspaper  half-tones,  and  the  great 
majority  of  those  in  magazines,  are  really 
composed  entirely  of  black  or  white ;  that 
is,  any  given  point  is  either  the  one  or 
the  other.  Examine  one  of  these  pictures 
closely  and  you  will  find  it  to  be  composed 
entirely  of  little  black  dots,  the  shaded 
effect  being  an  optical  illusion  due  to  the 
size  of  the  dots.  There  are  a  fixt  number 
of  these  dots  to  the  linear  inch,  varying  in 
newspaper  work  from  forty 
to  eighty.  If  the  half-tone  is 
what  is  known  as  sixty  screen, 
then  there  are  sixty  dots  to 
the  linear  inch;  and  the  light 
and  shade,  as  before  stated, 
is  produced  by  the  size  of  the 
dots,  the  lighter  portions  hav- 
ing small  dots  and  the  larger 
portions  large  dots  that  some- 
times join  and  produce  a  mass 
of  black. 

These  dots  may  of  course 
be  formed  of  insulation  and 
will  break  the  current  for  a 
period  of  time  proportionate 
to  their  size.  This  is  the  gen- 
eral idea  of  transmitting  a 
half-tone. 

Before  explaining  the  ex- 
act operation  of  my  picture 
transmitting  device,  it  may 
be  well  to  explain  the  method 
of  preparing  the  half-tone  in 
order  to  obtain  the  insulating 
dots.  For  this,  I  follow  up  to 
a  certain  point  the  regular 
process  of  photo-engraving. 
The  picture  to  be  transmitted  is  first 
photographed  thru  a  screen,  the  function 
of  which  is  to  break  up  the  picture  into 
dots  whose  sizes  vary  as  previously  ex- 
plained.   A  copper  or  zinc  plate  is  then 


December,  1917 


THE  ELECTRICAL  EXPERIMENTER 


517 


coated  with  a  solution  of  glue,  bichromat 
of  ammonia  and  water.  This  is  placed  in 
contact  with  the  developed  negative  and  is 
exposed  to  strong  light.  The  bichromat  of 
ammonia  is  the  element  acted  upon.  When 
the  plate  is  washed,  the  part  that  has  not 
received  the  light  washes  away,  leaving  the 
rest  fixt  to  the  plate.  Upon  heating,  the 
gelatine  picture  turns  to  a  chocolate  color. 
The  regular  photo-engraving  process  goes 
still  further,  but  this  is  all  that  is  necessary 
in  the  preparation  of  a  picture  for  trans- 
mission, as  the  dark  portions  form  a  very 
thin  and  highly  satisfactory  insulation. 

The  plate  is  then  rolled  into  a  thin  cylin- 
der and  slipt  over  the  cylinder  of  the 
machine.  The  transmitting  carriage  con- 
sists of  an  arm  into  the  end  of  which  may 
be  screwed  an  ordinary  phonograph  needle, 
which  is  held  against  the  plate  by  a  spring. 
A  current  passes  between  the  needle  and 
the  cylinder  excepting  when  an  insulating 
dot  passes  beneath  the  needle.  As  pre- 
viously explained,  the  mechanism  permits 
the  needle  to  cover  every  part  of  the 
picture.  In  this  manner  a  picture  is  trans- 
mitted. 

At  the  receiving  end  of  the  line,  the 
current  from  the  transmitting  machine 
passes  thru  the  coils  of  the  electro-magnets 
on  the  receiving  carriage.  These  attract 
a  very  light  armature,  causing  the  saffire  or 
diamond  in  the  forward  end  to  press  against 
the  cylinder  This  pressure  does  the  re- 
cording. The  stylus  may  be  made  to  cut  a 
stencil ;  scratch  camphor  smoke  from  white 
enameled  paper ;  scrape  white  wax  from  dark 
paper ;  or  press  upon  a  carbon  sheet,  thereby 
recording  and  reproducing  the  picture  upon 
ordinary  paper.  The  pictures  illustrating 
this  article  were  received  by  the  latter 
method.  In  this  manner,  all  the  dots  on  the 
sending  machine  are  accurately  reproduced 
on  the  paper  at  the  receiving  end.  These 
dots,  since  they  vary  in  size  according  to 
the  light  and  shade  of  the  picture,  form  an 
excellent  half-tone  likeness  of  the  original 
obj  ect. 

Some  of  the  readers  of  this  article  may 
wonder  why  the  recording  is  not  done  by 
making  a  pen  out  of  the  receiving  stylus 
and  causing  it  to  write  upon  ordinary  paper. 
The  reason  lies  in  the  fact  that  a  pen  and 
ink  arrangement  is  necessarily  more  com- 
plex than  the  system  above  explained;  it 
gets  out  of  order  easier,  and  when  recording 
at  the  rate  of  two  hundred  and  fifty-one 
dots  per  second,  which  is  the  speed  at  which 
a  picture  is  recorded,  it  is  not  as  efficient  as 
the  methods  described. 

The  construction  of  the  receiving  arm 
should  be  very  light  to  overcome  friction, 
gravity  and  inertia.  It  should  also  be  suf- 
ficiently stiff  to  avoid  vibration.  Friction 
can  be  very  largely  eliminated  by  using 
jeweled  bearings. 
The  electro-mag- 
nets used  for  actu- 
ating this  arm  may 
be  polarized  so 
that  the  current 
has  merely  to 
change  the  degree 
of  magnetization. 
It  is  possible  to 
make  a  receiving 
carriage  that  will 
respond  to  feebler 
impulses,  but  this 
is  not  as  desirable 
as  speed. 

By  connecting  a 
rheostat  in  series 
with  the  receiving 

carriage,  the  current  can  be  adjusted  to 
make  the  receiving  arm  record  as  efficiently 
as  possible,  and  pictures  can  be  made  lighter 
or  darker  at  will. 

There  is  another  detail  worth  mentioning 
in  regard  to  the  sending  apparatus.  Unless 


some  means  is  taken  to  prevent  it,  a  spark 
forms  at  the  break  of  the  current,  which 
of  course  takes  place  as  an  insulating  dot 
passes  under  the  needle.  This  can  be  pre- 
vented in  three  ways.  One  terminal  of  a 
condenser  may  be  connected  to  the  cylinder, 


wmm 


This  Reproduction  of  a  Photograph  By  the 
Leishman  Process  Shows  Particularly  Well 
the  Way  In  Which  Features  Are  Brought  Out. 
Hold  Picture  at  Arm's  Length  to  Obtain 
Best  Effect. 


and  the  other  to  the  needle ;  or  enough  re- 
sistance may  be  introduced  into  the  line  to 
absorb  the  energy;  or  resistance  may  be 
shunted  across  the  gap  so  that  the  current 
at  break  merely  becomes  too  weak  for  the 
electro-magnets  at  the  receiving  machine 
to  attract  the  recording  arm.  The  latter 
plan  has  the  advantage  of  reducing  what 
may  be  called  the  inertia  of  the  line,  due  to 
its  capacity  and  inductance.  This,  however, 
is  of  little  consequence  excepting  in  long 
distance  work. 

So  far  as  the  use  of  this  system  with 


Synchronous  / 
dri  ving  ■     threaded  shaft  /         Jena/  YT7 
machine      /     ■.  ..  Travelling  orm  V" 


Rhecstat 


Q\  Spt  absorber  {mho HI  I 
^     (resistance)  .  >™™u 


B  Bat 

—Radio  Receiving  Set — 


General  Arrangement  of  Leishman  Transmitting  and  Reproducing  Apparatus  for  Telegraph- 
ing a  Picture  Via  Wireless. 


wires  is  concerned,  there  remains  to  be 
discust  only  the  synchronising  of  the  send- 
ing and  receiving  cylinders.  It  sometimes 
happens  that  power  is  furnished  from  the 
same  generator  at  fairly  distant  points.  In 
this  instance,  synchronism  is  merely  a  mat- 


ter of  using  synchronous  induction  motors. 
But  in  the  great  majority  of  cases,  no 
such  convenience  may  be  resorted  to.  It  is 
then  best  to  use  direct  current  motors 
operated  by  storage  batteries  with  a  sliding 
contact  rheostat  in  the  circuit. 

The  operator  of  the  receiving  instrument 
watches  the  recording  of  the  picture;  and, 
if  the  machines  are  not  in  perfect  synchro- 
nism, he  is  warned  by  a  deviation  of  the 
straight  lines  formed  by  the  picture's  upper 
and  lower  borders.  If  the  line  turns  in 
one  direction,  his  motor  is  going  too  slow, 
so  he  cuts  out  some  of  the  resistance.  An 
opposite  deviation  warns  him  to  move  the 
handle  of  the  rheostat  the  other  way.  When 
storage  batteries  are  used,  the  current  is 
steady  and  very  little  adjusting  of  the  rheo- 
stat is  required. 

Automatic  synchronization  is  of  course 
desirable.  One  means  of  doing  this,  which 
greatly  interferes  with  speed,  very  much 
resembles  the  method  used  by  the  Western 
Union  Telegraph  Company  for  hourly  cor- 
recting their  "standard  time"  clocks.  At 
each  revolution  of  the  sending  cylinder  a 
heavy  current  is  sent  to  the  receiving  ma- 
chine, magnetically  correcting  the  cylinder 
by  stopping  it  momentarily.  Some  such 
means  for  synchronizing  is  absolutely  neces- 
sary where  the  recording  is  not  visible ; 
but  where  the  recording  can  be  seen,  manual 
control,  of  the  nature  described,  may  be 
used,  altho  mechanical  synchronizing  is 
preferable.  I  have  recently  designed  a  ma- 
chine for  this  purpose — one  that  is  far 
ahead  of  the  system  described  above,  but 
at  the  present  time,  I  do  not  wish  to  disclose 
the  details.  The  system  permits  the  cylin- 
ders to  revolve  continuously,  and  the 
receiving  machine  may  be  started  and  stopt 
from  the  transmitting  end. 

A  good  deal  has  been  said  regarding  the 
operation  of  my  system  by  radio.  It  will 
be  obvious  that  the  transmitting  apparatus 
may  be  connected  into  the  circuit  instead  of 
the  wireless  key,  and  the  picture '  trans- 
mitted in  the  usual  manner.  At  the  receiv- 
ing end,  an  Audion  detector  and  amplifier 
make  the  signals  sufficiently  strong  to  op- 
erate a  relay,  and  this  throws  in  a  local 
circuit  to  record  the  picture. 

It  may  be  of  interest  that  I  have  re- 
cently applied  for  a  patent  on  an  entirely 
different  method  of  transmitting  photo- 
graphs, this  scheme  permitting  the  cylinders 
to  revolve  at  about  ten  revolutions  per 
second.  This  particular  apparatus  makes 
use  of  the  automatic  control  previously 
mentioned.  On  this  system,  gravity  and 
inertia  have  no  effect,  and  all  friction  is 
eliminated,  excepting  that  caused  by'  the 
turning  of  the  cylinders. 

At  the  beginning  of  this  article  it  was 
stated  that  tele-vision-  is  at  present  impos- 
sible for  both  me- 
chanical and  elec- 
trical reasons. 
These  facts  are  in- 
teresting,   and  I 
wish  to  rnention 
them,  for  the  bene- 
fit of  all  -  electrical 
experimenters.  As 
before  explained, 
the    best.-,  moving 
pictures  require 
seventeen  flashes  a 
second.     For  the 
sake    of  explana- 
tion,   let   us  con- 
sider the  transmis- 
sion of  one  picture 
per  second,  and  let 
the  picture  be  one  of  the  easiest  to  trans- 
mit— a  portrait,  for  instance.    The  picture 
should  be  gone  over  from  top  to  bottom 
by  the  electric  "eye"  in  the  neighborhood  of 
four  hundred  times.   This  would  necessitate 
{Continued  on  page  572) 


518 


THE  ELECTRICAL  EXPERIMENTER 


December,  1917 


PHOTOGRAPHING  LIGHTNING. 

To  many  timid  persons  the  fine  art — for 
art  it  really  is — of  snap-shotting  "lightning" 
is  actually  about  the  most  dangerous  job  to 


An  Excellent  Photograph  of  Ribbon  Light- 
ning Taken  In  Iowa  the  Past  Summer.  This 
Is  What  We  Mean  by  "Odd  Photos." 

be  found.  But  many  amateurs  and  profes- 
sionals have  taken  excellent  photographs  of 
lightning  discharges  and  still  live  to  tell 
the  tale.  For  instance  witness  the  accom- 
panying photo  taken  last  summer  by  the 
Rev.  C.  Lilie,  of  Iowa. 

To  take  a  good  "lightning"  photo  is  more 
often  than  not  a  matter  of  pure  chance. 
Having  loaded  up  the  camera,  the  first  thing 
to  do  is  to  open  the  shutter  for  a  time  ex- 
posure; as  soon  as  the  first  flash  appears 
close  the  shutter  quickly.  The  job  is  done. 
Simply  develop  the  plate  in  the  usual  man- 
ner. Heat  or  flash  lightning  will  give  pecu- 
liar results.  The  writer  took  several  photos 
of  heat  lightning  recently  and  the  results 
are — an  ordinary  photograph  of  the  sur- 
rounding landscape,  just  as  if  the  sun  had 
been  shining.  Combinations  of  forked  and 
heat  lightning  often  yield  excellent  pictures. 
Chain  or  forked  lightning  will  produce  a 
startling  photo  if  the  camera  is  swung  from 
side  to  side  while  taking  the  picture. 


ELECTRICITY  AND  GOLD  FISHES. 

By  H.  Gernsback 

Not  so  long  ago,  the  writer,  while  watch- 
ing some  gold  fishes  at  play  in  his 
aquarium  had  the  idea  of  testing  the  fishes 
as  to  the  effect  electricity  would  have  upon 
these  highly  sensitive  animals.  Accordingly 
two  metal  plates  were  sunk  into  the  tank 
as  shown  in  the  illustration,  and  three 
batteries  were  connected  to  the  two  plates. 

A  curious  thing  at  once  happened.  Using 
a  current  of  three  dry  cells  and  upon  clos- 
ing the  switch,  all  the  fish  immediately 
grouped  themselves  parallel  with  the  plates 
and  as  long  as  the  current  was  left  on  the 
fish  remained  in  this  position,  refusing  to 
swim  or  move  in  any  other  way  but  parallel 
to  the  plates. 

The  explanation  of  this  phenomenon  of 
course  is  that  the  current  traveling  from 
plate  to  plate,  traverses  the  fishes'  bodies, 
and  as  a  fish  is  longer  than  it  is  wide,  and 
as  it  is  quite  sensitive  to  the  electrical  cur- 


rent, it  follows  that  inasmuch  as  the  current 
probably  proved  disagreeable  to  the  ani- 
mal, it  presented  the  shortest  path  to  the 
current  by  placing  itself  parallel  to  the 
plates.  It  seems  the  fish  did  not  cherish 
the  idea  of  taking  the  full  strength  of  the 
current  thru  the  nose  and  mouth  and  thence 
thru  the  sensitive  fins  of  the  tail. 

Another  thing  observed  was,  that  the 
moment  the  switch  was  closed,  there  was  a 
certain  amount  of  excitement  among  the 
fish  and  if  the  closing  and  the  opening  of 
the  switch  was  kept  up,  they  would  dart 
around  in  a  most  extraordinary  manner, 
while  thus  under  the  influence  of  the  cur- 
rent. As  soon  as  the  current  was  turned 
on  and  left  on,  however,  the  fish  did  not 
seem  to  be  uncomfortable  except  that  they 
only  moved  parallel  with  the  plates  as  above 
mentioned.  Another  point  observed  was 
that  while  under  the  influence  of  the  elec- 
trical current,  the  fish  refused  to  come  up 
and  feed  tho  quite  hungry,  having  gone 
without  food  for  twenty-four  hours.  The 
instant  the  current  was  disconnected,  the 
fish  immediately  would  begin  feeding,  but 
did  not  seem  to  be  quite  so  anxious  as  at 
other  times.  This  would  tend  to  show  that 
the  electrical  current  was  not  of  immediate 
benefit  to  them,  altho  this  can  not  be  vouch- 
safed, the  experiment  having  not  extended 
over  a  sufficiently  long  period.  At  any  rate, 
the  fish  did  not  seem  to  be  harmed  by  the 
continuous  application  of  the  current,  and 
after  a  few  hours,  seemed  to  be  as  lively 
as  ever. 


When  Battery  Current  Was  Connected  to  Two 
Metal  Plates  in  a  Gold  Fish  Aquarium,  the 
Fish  Immediately  Grouped  Themselves  Par- 
allel With  the  Plates,  as  Shown  in  Lower  Cut. 


Alternating  current  from  a  step-down  toy 
transformer  was  also  tried,  but  strange  to 
say  the  fish  were  hardly  affected  by  this 
form  of  current.  This  was  rather  unex- 
pected, inasmuch  as  a  rather  convulsive 
action  of  the  fish  was  thought  to  take  place. 


ELECTRICITY  WASHES  CLOTHES 
FOR  U.  S.  TARS. 

"Somewhere  on  the  Atlantic,"  electricity 
is  "taking  in  washing" — doing  good  work 
for  Uncle  Sam's  Tars.  On  the  supply,  or 
"mother,"  ship  an  American  electric  laun- 
dry is  operated,  said  to  be  the  most  com- 
plete and  modern  ever  seen  in  that  part  of 
the  world.  The  "boys"  report  that  the 
work  is  perfect,  and  prices  less  than  half 
those  at  home.  One  of  the  features  of  the 
ship's  laundry  is  a  complete  soap  factory. 


NURSERY  RHYMES  TO  DATE. 

By  John  T.  Dwyer. 
Sing  a  song  of  sixpence, 
Of  "muckers"  brave  and  bold, 
Who  turn  the  household  upside  down 
In  search  of  things  untold — 
Pins  and  needles;  clocks  and  jars, 
All  articles  of  use 
Are  soon  upon  the  missing  list, 
When  a  "mucker"  is  turned  loose. 

Little  Jack  Horner, 

Sat  in  a  corner 

Eating  a  CURRENT  pie. 

He  put  in  his  thumb, 

And  then  cried,  "by  gum ! 

This  is  SHOCKING  indeed,  Oh!  my." 

3|G        &        $        $        ♦       *        *  I 

There  is  a  fellow  in  our  town 
And  he  is  wondrous  wise, 
The  things  he  doesn't  know  about 
Would  fill  a  "skeeter's"  eyes. 

Now,   it's  got  some  folks  a'guessing 
How  he  could  get  such  knowledge, 
The  more  so,  when  they  do  consider 
That  he  never  went  to  college. 

But  to  me  the  matter's  simple — 
And  the  reason  can  be  seen; 
He's  merely  one  of  many  more 
WHO  READ  THIS  MAGAZINE. 


NOVEL   SHADE   FOR  INCANDES- 
CENT LAMPS. 

A  simple  design  for  an  efficient  incandes- 
cent lamp  shade  is  described  in  a  U.  S. 
patent  recently  issued  to  Frederick  R.  Pope 
of  London,  England.  This  invention  de- 
scribes a  type  of  shade  which  closely  sur- 
rounds the  upper  portion  of  the  lamp  bulb, 
and  which  also  serves  as  a  reflector  to  di- 
rect and  concentrate  the  light  rays.  It  is 
claimed  to  be  particularly  efficient  in  loca- 
tions where  the  supporting  structure  for  the 
lamp  is  subject  to  a  heavy  vibration,  as  in 
factories  and  like  places. 

The  arrangement,  in  brief,  comprises  an 
annular  threaded  collar,  which  screws  on 
to  a  threaded  sleeve  on  the  lamp  base 
proper.  The  collar  is  preferably  U-shaped 
in  cross-section,  and  forms  a  seat  for  a 
flange  formed  on  the  narrow  end  or  neck 
of  the  shade.  The  shade  may  be  of  por- 
celain or  any  other  material  suitable  for 
the  purpose.  It  is  very  easy  to  replace  the 
shade  at  any  time,  as  the  shade  as  well  as 
the  retaining  collar  both  slip  over  the  lamp 
base,  as  they  are  both  of  larger  diameter 
than  the  screw  plug  forming  the  base  of 
the  lamp. 


An  Electric  Shade  for  Incandescent  Lamps 
That  Screws  Onto  a  Threaded  Collar,  so  as 
to  Be  Supported  by  the  Lamp  Itself. 


December,  1917 


THE  ELECTRICAL  EXPERIMENTER 


519 


ELECTRICALLY   HEATING  THE 
FISH  TANK. 

The  advantages  to  be  obtained  from  the 
heat  of  electric  energy  are  many  and  great, 
both  as  regards  thermal  efficiency  as  well 
as  ease  of  application.  Greater  thermal 
efficiency  is  obtained  in  that  electric  energy 
is  transformed  into  heat  at  100%  efficiency 
and  is  utilized  at  from  2>y2  to  4  times  the 
efficiency  of  fuel  combustion  devices. 

Here  we  have  the  Fish  Tank  electric 
heater.  The  customer  has  an  aquarium  in 
his  residence  containing  fish  brought  from 
a  warm  climate.  This  necessitates  warm- 
ing the  water  which  is  accomplisht  by  in- 
stalling a  heater  of  the  immersion  type  in 
the  feed  pipe  supplying  water  to  the  tank. 
This  heater  unit  is  indicated  by  the  arrow 
in  the  photograph. 

Among  other  things,  electrically  made 
heat  is  clean,  safe  and  sanitary.  It  can  be 
used  in  any  atmosphere  and  generated  in 
any  quantity  or  at  any  temperature  desired. 
By  its  use  the  fire  hazard  is  greatly  reduced 
and  the  working  conditions  of  labor  vastly 
improved.  It  is  susceptible  of  perfect  and 
automatic  control  as  regards  localization, 
time  and  temperature  to  an  extent  not  yet 
attained  with  any  other  method,  and  exact 
conditions  can  be  duplicated  at  will. 

The  heating  unit  is  invariably  small,  com- 
pact and  substantially  built,  which  allows  of 
greater  flexibility  in  application  than  with 
any  other  heating  device.  When  applied  to 
various  industries  or  processes  of  those  in- 
dustries each  unit  has  its  own  specific  ad- 
vantage. 

In  heating  of  liquids,  melting  of  metal  in 
pots  and  hotplate  work,  the  units  are  so 
shaped  and  embedded  in  the  apparatus  used 
and  of  such  thermal  characteristics  as  to 
accomplish  the  work  with  the  least  possible 
expenditure  of  time  and  energy  and  at  high- 
est efficiency. 


"GIVE  SOMETHING  ELECTRICAL 
THIS  CHRISTMAS." 

Higher  wages,  consequently  more  money 
to  spend;  a  newly  created  desire  for  con- 


veniences and  the  demand  for  thrift  are 
all  working  to  make  this  year  the  banner 
Christmas  year  for  the  electrical  industry. 

The  strong  appeal  of  practical  electrical 
gifts  for  the  home  will  bring  scores  of  peo- 
ple into  the  electrical  shops  where  formerly 
they  have  been  buying  toys  and  knickknacks, 


WOMEN   MAKE  GOOD  RADIO 
OPERATORS. 

The  accompanying  illustration  shows  a 
number  of  women  being  taught  the  rudi- 


ments of  Radio-telegraphy  at  one  of  the 
leading  colleges  in  New  York  City. 

The  photograph  is  reproduced  thru  the 
courtesy  of  the  National  League  for  Wom- 
en's Service.  These  women  who  take 
up  the  study  of  wireless  will  find  plenty 
to  do  in  helping  their  country  to  win  the 
war. 


and  realizing  the  trend  of  opinion,  The  So- 
ciety for  Electrical  Development  has  planned 
a  big  nation-wide  Christmas  Gift  Cam- 
paign. The  broadside  announcing  this 
Campaign  has  been  mailed  to  20,000  per- 
sons. The  features  of  "America's  Electri- 
cal Christmas"  are  outlined  and  informa- 
tion given  regarding  the  display  publicity 
material  available  to  help  the  electrical  in- 
dustry get  its  share  of  the  $200,000,000  an- 
nually spent  for  holiday  presents. 

Remembering  the  success  of  "Electrical 
Prosperity  Week,  1915",  "America's  Elec- 
tical  Week,  1916",  "Wire  Your  Home 
Time",  central  stations,  manufacturers,  job- 
bers and  contractor-dealers  will  realize 
upon  this  opportunity.  The  electrical  in- 
dustry never  has  gotten  its  share  of  the 
big  money  spent  in  Christmas  gifts.  This 
is  the  first  concerted  effort  in  this  direction, 
and  the  time  is  opportune  for  an  immense 
business. 

The  sales  helps  being  prepared  for  the 
campaign  with  the  slogan  "Give  Something 
Electrical  This  Christmas"  include  a  spe- 
cial holiday  edition  of  the  Monthly  Sales 
Service  of  the  Society.  Timely  advertising 
suggestions  will  be  given  and  special  win- 
dow displays  will  be  shown. 

CORRECTION  NOTICE. 

We  wish  to  correct  a  statement  made  in 
the  article  entitled  "Historic  Electric  Ap- 
paratus," which  appeared  in  the  November 
issue,  concerning  the  history  of  "Wireless." 
The  first  trans-Atlantic  radio  signal  (the 
letter  "S")  was  recived  at  St.  Johns,  New- 
foundland, instead  of  Cape  Cod,  Mass. 


Photo  Courtesy  Society  for  Electrical  Development 
This  Picture  Shows  How  an  Electrical  Heater  (See  Arrow)  Was  Adapted  to  Warm 
the  Water  in  a  Fish  Tank  Containing  Tropical  Members  of  the  Finny  Tribe 


520 


THE  ELECTRICAL  EXPERIMENTER 


December,  1917 


FAN   FLAME   SPARK   PLUG  THE 
LATEST. 

Any  plug  will  spark  when  it's  new  and 
clean.  But  no  ordinary  spark  plug  actually 
adds  power  to  the  motor,  actually  cleans 
itself,  and  still  is  so  simple  and  sturdy  in 
construction  that  it  is 
unaffected  by  the  most 
severe  conditions  of 
heat,  speed  and  high 

■ compression    say  the 
j .      )|j        sponsors  of  the  Fan 
Flame  plug. 
I     i  H  The     center  elec- 

trode of  the  fan 
flame  plug  terminates 
in  a  miniature  rotary 
fan  which  is  heat 
proof  because  it  is 
'jgffFl  9H'/o  pure  nickel.  This 
m^mm~  fan  is  constantly  ro- 
tated at  high  speed  by 
the  successive  com- 
pressions and  explo- 
sions. 

The  whirling  fan 
produces  a  circle  of 
flame  instead  of  a 
mere  spark.  It  liter- 
ally throws  a  shower 
of  fire  in  every  direc- 
tion, igniting  the  com- 
prest  gas  several 
times  as  rapidly  as  an 
ordinary  spark  can  do 
it. 

By  careful  tests  the 
makers  claim  to  have 
proved  that  the 
nickel  fan  constantly 
rotates  in  the  cylinder  when  the  engine  is 
in  operation. 

The  effect  of  the  rapidly  whirling  blades 
is  to  throw  off  all  oil  and  soot  by  centrifu- 
gal force  so  that  the  sparking  points  are 
always  clean,  and  the  accumulation  of  soot 
on  the  rest  of  the  plug  is  also  retarded. 


This  Spark  Plug 
Has   a    Fan  Elec- 
trode  That  Re- 
volves. 


A  40,000  AMPERE  SWITCH. 

The  accompanying  illustration  shows  a 
remarkable  end-cell  storage  battery  switch 
which  has  a  steady  capacity  of  10,000  am- 
peres or  a  momentary  load  of  40,000 
amperes  for  six  minutes.  It  is  used  for 
regulating  the  voltage  of  storage  batteries 
in  large  central  stations. 

The  construction  of  the  10,000  ampere 
cell  switches  is  shown  clearly.  Each 
switch  has  two  horizontal  rails  of  rec- 
tangular section  and  two  rows  of  massive 
contact  points,  arranged  alternately  at  the 
corners  of  an  imaginary  square,  the  four 


traveling  brushes  occupying  the  sides  of 
the  square.  The  brushes  are  mounted  on 
and  suitably  insulated  from  a  traveling 
carriage,  driven  by  the  horizontal  driving 
screw.  Two  10,000  ampere  cell  switches 
are  shown  in  the  illustration  herewith. 

The  driving  screw  in  each  case  runs  the 
entire  length  of  the  switch,  and  is  geared 
to  a  motor  at  one  end.  This  motor  is  pro- 
vided with  semi-automatic  distant  control, 
so  that  the  switchboard  operator 
can  start  the  brush  in  either  direc- 
tion from  any  point  and  bring 
it  into  full  contact  with  any  other 
point,  but  cannot  stop  it  between 
two  adjacent  points. 

Two  electro-magnets,  of  the 
plunger  type,  located  adjacent  to 
the  motor  and  excited  selectively 
by  the  control  circuit  from  the 
switchboard,  serve  to  operate  con- 
tact switches  to  connect  the  motor 
armature  for  either  direction  of 
travel,  respectively.  As  soon  as 
either  plunger  starts  upward  it 
breaks  the  exciting  circuit  of  the 
other  magnet,  thus  preventing  any 
possible  conflict  between  the  two. 

As  soon  as  the  motor  starts,  a 
cam  wheel  so  geared  to  the  motor 
as  to  make  one  complete  revolu- 
tion while  the  brush  is  traveling 
between  two  adjacent  points,  locks 
the  active  magnet  plunger  in  position,  thus 
maintaining  the  motor  in  constant  action 
between  switch  points. 


from  the  incandescent  lamp  are  cast  into 
the  eyes  of  the  physician,  and  more  free- 
dom of  the  hands  is  obtained  by  its  use  as 
becomes  readily  apparent,  owing  to  the  fact 
that  three  separate  and  distinct  instruments 
are  combined  in  one.  A  push-button  switch 
is  provided  to  open  and  close  the  lamp- 
circuit  as  desired.  This  idea  has  been  pat- 
ented by  Hermann  Weder,  Sr.,  and  Charles 
H.  Wolff  of  Philadelphia,  Pa. 


A  Recent 
and 


Invention  Comprises  a  Diagnostic  Lamp,  Lens, 
Tongue- Depressor  All  in  One  Instrument. 


HEATING  PERSONS  INSTEAD  OF 
ROOM  IN  WESTERN  RESTAU- 
RANT. 

In  following  up  the  policy  of  "localizing 
heat,"  a  leading  electric  heating  concern 
recently  secured  a  contract  covering  the 
installation  of  30  electric  heaters  in  the 
Tuberculosis  Sanitarium  of  Independent 
Order  of  Foresters  in  Lopez  Canyon,  a 
short  distance  from  Los  Angeles. 

These  heaters  will  be  installed,  without 
the  stands,  on  the  under  side  of  the  table 
in  the  dining-room,  radiating  the  heat  down- 
ward to  strike  the  floor  and  be  radiated  up, 
by  this  means  keeping  the  bodies  of  those 
at  the  dining  table  warm,  rather  than  at- 
tempting to  heat  all  the  air  in  the  room. 
In  other  words,  they  heat  the  individual 
instead  of  heating  the  room.  Inasmuch  as 
the  diners  will  only  be  in  the  room  20 
minutes,  or  half  an  hour  during  meals  three 
times  a  day,  it  seemed  unnecessary  to  at- 
tempt to  heat  the  entire  room,  accommo- 
dating over  100  people,  when  it  would  only 
be  occupied  this  short  period  of  time. 


E.S.B.C0.E90 


Rear  View  of  the  Largest  Storage -Battery  End-Cell  Switch  Ever  Built. 
It   Has   a   Continuous   Carrying   Capacity   of   10,000   Amperes   and  a 
Momentary  Capacity  of  40,000  Amperes. 


COMBINED 
FLASHLIGHT 
AND  LENS  FOR 
DIAGNOSTIC 
PURPOSES. 

The  present  inven- 
tion shown  in  the 
accompanying  illustra- 
tion is  an  ingenious 
arrangement  combin- 
ing a  special  form  of 
pocket  flashlight  with 
an  adjustable  lens 
holder  on  the  side  of 
the  battery  case,  and 
also  means  for  attach- 
ing several  forms  of 
diagnostic  instru- 
ments, such  as  a 
tongue  depressor, 
which  is  here  shown 
in  actual  use. 

Several  advantages 
are  claimed  for  this 
particular  form  of 
flashlight  diagnostic 
instrument ;  for  one 
thing,  no  direct  rays 


UNIQUE  COMBINATION  SIGNAL- 
ING LAMP  AND  BELL. 

In  many  instances,  the  orthodox  form  of 
electric  signal  or  alarm  is  not  desirable,  and 
with  these  objects  in  mind,  Mr.  Christian 
Reinker,  an  Ohio  man,  has  devised  and 
patented  the  unique  combination  signal 
lamp  and  bell  shown  in  the  illustration 
herewith.  Current  is  supplied  to  the  device 
from  a  battery  or  other  source  of  current 
thru  two  binding  posts  carried  on  the 
central  stem  at  the  base  of  the  bell,  and 
when  the  circuit  is  closed,  the  bell  vibrates, 
while  the  lamp  remains  lighted  constantly, 
as  long  as  the  switch  remains  closed.  The 
design  of  the  signaling  device  is  unusually 
artistic,  the  lamp  being  enclosed  in  an 
ornamental  chamber  which  is  provided  with 
one  or  more  white  or  colored  lenses  cut  in 
the  form  of  jewels. 


Unique  Electric  Signaling  Device  for  Use  on 
Autos,  etc.    Pushing  a   Button    Lights  the 
Lamp   and    Rings   the  Bell. 


December,  1917 


THE  ELECTRICAL  EXPERIMENTER 


521 


OPERATING    THE  COFFEE 
CUTTER  BY  ELECTRIC 
MOTOR. 

By  means  of  the  cutter  shown  herewith 
steel-cut  coffee  can  be  furnished  by  the 
grocer  in  bulk  with  convenience  and  at  a 
profit.  It  is  built  along  entirely  different 
lines  from  any  of  the  mills  on  the  market, 
and  has  been  evolved  to  meet  the  insistent 
demand  for  machines  that  would  cut,  not 
grind,  coffee. 

The  coffee  cutter  cuts  the  coffee  uni- 
forraly  and  evenly.  Granulating  and  pul- 
verizing are  (lone  on  the  same  burrs,  giving 
a  sandTitee  grain  especially  adapted  to  all 
kinds  of  percolators  or  drip  pots  now  in 
such  wide  use.  There  are  two  sets  of 
burrs,  one  of  wkich  revolves.  The  other 
set  is  stationary.  The  burrs  are  especially 
designed  with  diamond-shaped  teeth.  They 


THIS  FAN  THROWS  BREEZE  "UP 
AND  DOWN"  AS  WELL  AS 
SIDEWISE. 

The  past  few  years  have  witnesst  so 
many  novel  introductions  in  "Fanland"  that 


No  Up-To-Date  Grocery  Store  Is  Complete 
Without  an    Electric   Coffee  Cutter. 

are  self-sharpening  and  self-aligning,  hav- 
ing special  ball  bearings  which  take  out 
all  play.  Thus  the  burrs  cannot  "wobble" 
and  produce  uneven  granulation. 

These  machines  are  operated  by  totally 
enclosed,  low-speed  electric  motors  de- 
signed for  heavy  duty  and  without  com- 
plicated mechanism  to  need  adjustment. 
Due  to  the  fact  that  a  low-speed  motor 
is  employed,  no  gears  are  necessary.  The 
motors  are  equipt  with  radial  and  thrust 
ball  bearings,  which  reduce  friction  to  a 
minimum  and  prevent  wobbling  of  parts. 
They  are  silent  and  true  running.  The 
only  parts  needing  lubrication  are  the  ball 
bearings,  and  these  need  only  be  oiled 
about  once  a  year.  Thus  there  is  no 
oil  to  accumulate  in  the  burr  case,  none  to 
get  into  the  coffee,  and  all  the  nuisance 
of  oiling  is  removed. 


This  Remarkable  tlectrlc  Fan  Revolves  and 
Throws  a  Breeze  Up  and  Down  as  Well  as 
Sidewise. 

it  would  seem  that  about  every  imaginable 
form  of  electric  fan  had  been  perfected  or 
thought  of,  but  we  have  to  salute  Gustaf 
Olson  of  Chicago,  111.,  for  his  very  ingen- 
ious electric  fan  gear. 

One  of  the  most  interesting  points  which 
had  to  be  worked  out  in  this  idea  was  the 
shape  of  the  gear  teeth  on  the  stationary 
rack,  and  also  those  of  the  pinion  which 
meshes  with  this  rack,  as  becomes  clear 
from  the  accompanying  illustration.  The 
small  driving  pinion  which  rotates  the  fan- 
motor  body  proper,  by  means  of  this  rack, 
is  secured  to  a  vertical  shaft  geared  inside 
the  motor  casing  to  the  armature  shaft,  so 
as  to  provide  a  positive  drive  for  the  rota- 
tional function. 

Current  is  supplied  to  the  rotating  fan 
motor  thru  a  set  of  slip  rings  and  brushes 
mounted  in  the  base.  Thus,  this  fan  will 
not  only  throw  a  breeze  in  every  part  of 
the  room  at  a  certain  level,  but  will  throw 
the  breeze  toward  the  floor  and  also  toward 
the  ceiling  periodically  or  about  four  times 
in  every  revolution  of  the  fan  motor,  which 
may  be  adjusted  to  occupy  about  one  fifth 
of  a  minute.   

GLASS   EYELETS   FOR  TEMPOR- 
ARY WIRING. 

Glass  push  pins  provided  with  an  eyelet 
for  use  in  temporary  low-voltage  wiring 


are  being  made  now.  The  pins  are  easily 
attached  to  woodwork  or  walls,  and  it  is 
pointed  out  by  the  maker  that  they  are 
particularly  useful  for  amateur  battery 
work  where  small  wires  are  to  be  run 
about  the  house.  They  should  prove  par- 
ticularly efficient  in  wiring  up  sensitive 
electrical  apparatus  such  as  galvanometers, 
radio  receiving  apparatus,  etc.,  where  a 
slight  leak,  such  as  thru  wood,  means  a 
big  difference  in  the  efficiency  of  the  in- 
strument. 


AN 


NEXT!     WILL    YOU  HAVE 
ELECTRIC  HAIR-CUT? 

Barbering  is  one  of  the  very  old  and 
universal  trades.  For  years  past  there  has 
been  practically  no  advance  or  change  in 
the  general  method  employed  of  using 
shears,  razor  or  clipper.  It  is  true  that 
the  modern  clipper  with  its  improvements 
is  a  device  which  is  of  comparatively  re- 
cent development,  but  aside  from  that  the 
methods  of  the  barber  are  the  same  as 
they  were  hundreds  of  years  ago,  so  we 


A  Handy  Glass  Eyelet  for  Temporary  or  Low- 
Voltage  Wiring. 


Good  Morning!    Have  You  Met  the  Electric 
Barber?     Here's  the   Latest  Tonsorial  De- 
vice— A    Motor- Driven  Hair-Clipper. 

had  begun  to  believe  that  it  was  only  styles 
in  trimming  the  hair  or  beard  which 
change.  But  electricity  can  improve  almost 
any  unelectrified  method  or  device.  The 
electric  hair  cutter  here  illustrated  is  rapid- 
ly becoming  popular,  many  Chicago  barbers 
speaking  very  highly  of  it. 

As  will  be  seen  from  the  illustration, 
the  machine  consists  principally  of  a  light 
iron  standard  with  cross  arms  at  the  top 
supporting  the  small  electric  motor,  which 
is  connected  to  the  clipper  by  means  of  a 
flexible  shaft  three  or  four  feet  long.  This 
shaft  enters  a  translating  device  in  which 
the  revolving  motion  is  changed  to  a  hori- 
zontal motion  for  the  handles  of  the  clip- 
per. This  is  necessary  in  order  to  cause 
the  shearing  edges  of  the  moving  clipper 
blade  to  pass  back  and  forth  over  the  other 
in  the  usual  manner. 


522 


THE  ELECTRICAL  EXPERIMENTER 


December,  1917 


A  TRACKLESS  TROLLEY  SYSTEM. 
By  L.  Schoolcraft. 

In  Massachusetts  there  are  now  several 
lines  of  trackless  trolleys.  These  vehicles 
resemble  automobiles  more  than  they  do 
street  cars,  but  their  motive  power  is  elec- 
tric and  the  current  is  obtained  from  over- 
head trolley  wires. 


the  lungs  or  in  the  pleural  cavity,  just 
where  a  sore  is  situated.  If  the  child  has 
swallowed  a  pin  or  a  penny,  it  will  be 
nicely  revealed. 

There  are  forsooth  failures  with  it:  not 
every  use  of  the  X-rays  is  successful  in  it- 
self. Tuberculosis  may  be  present  and 
escape  discovery,  if  the  other  facts  found 


Massachusetts  Now  Boasts  a  Trackless  Trolley.    The  Current  Is  Taken  from  Two 
Wires  Thru  the  Double  Pole  Arrangement  Shown.    The  Vehicles  May  Pass  One 
Another  on  the  Road  Without  Trouble. 


It  will  be  noticed  in  the  illustration  that 
there  are  two  trolley  poles  on  this  car  as 
well  as  two  over-head  wires,  whereas  in 
the  ordinary  street  car  there  is  but  one. 
This  is  due  to  the  fact  that  these  cars  do 
not  run  on  steel  tracks  but  on  an  ordinary 
road  or  pavement.  The  second  trolley  wire 
being  for  the  return  circuit.  The  cars  are 
controlled  by  the  ordinary  controller  as  is 
found  in  street  cars. 

There  are  two  advantages  of  this  system 
of  trolley — 

First — The  car  may  pass  around  other 
vehicles  which  may  be  in  front  of  it  or 
passing  it  in  an  opposite  direction,  thus  re- 
ducing delays. 

Second — The  elimination  of  one  of  the 
largest  items  of  expense  in  constructing 
electric  railways  which  is  the  track  or  foun- 
dation.   

THE  USE  OF  X-RAYS  IN  DISEASES 
OF  THE  CHEST. 
By  Dr.  Leonard  Keene  Hirshberg, 
A.B.,  M.A.,  M.D. 

(Johns  Hopkins  University.) 

When  you  look  thru  the  greenish  glass 
used  as  a  screen,  when  the  X-rays  are 
focused  on  anyone's  torso,  you  see  an  old 
time  bird-cage  or  wire  hoop-skirt  with  the 
ribs  as  circular  wires,  with  shadowy,  fugi- 
tive, fleeting  phantoms  of  birds  within  the 
age.  An  X-ray  photograph  imprisons 
this  picture. 

The  X-rays,  with  the  ribs  as  precise  guid- 
ing posts,  allows  us  to  make  an  exact  and 
minute  examination  of  the  topography  hid- 
den from  the  unaided  human  senses.  A 
man  without  senses  is  a  mental  wreck. 
A  doctor  with  all  his  senses  is  a  most  in- 
complete creature.  He  must  call  to  the 
aid  of  his  best  endowments,  those  instru- 
ments of  precision,  which  reach  out  to  hid- 
den things  undreamt  of  in  his  best  senses, 
much  less  his  philosophy.  The  X-rays  is 
one  of  many  such  assistants. 

The  X-rays  can  sometimes  tell  you  to 
the  fraction  of  an  inch,  the  exact  spot  in 


in  a  physical  examination  are  not  also 
taken  into  consideration. 

In  maladies  of  the  lungs,  Dr.  Howard 
Lilienthal  of  the  surgical  staff  of  Cornell 
Medical  College,  holds  that  no  final  judg- 
ment should  be  given  unless  the  X-ray  ob- 
servations are  also  checked  up  with  other 
soundings  and  investigations  of  the  indi- 
vidual's state  of  health.  He  describes  a 
little  boy's  condition  in  support  of  this. 

The  little  patient  in  question  was  three 
and  a  half  years  old.    He  began  to  have 
spells  of  unproductive  cough.    There  was 
no  evidence 
of  fever  or 
we  a  k  n  e  s  s 
for  the 
young- 
ster  played 
about  be- 
t  w  e  e  n  the 
paroxysms. 

When  this 
had  gone  on 
about  ten 
days,  he 
really  be- 
c  a  m  e  se- 
riously ill. 
Fever  ap- 
peared and 
the  little  fel- 
low began 
to  cough  up 
mucus. 

An  exam- 
ination with 
the  -stetho- 
scope  and 
fingers  o  n 
the  back  of 
the  chest, 
showed  it  to 
be  a  bit  flat 
and  dull  in 
sound  with 
incre  a  s  e  d 
voice  pro- 


duction. It  was  decided  that  there  must  be 
some  fluid  or  pus  between  the  lung  and 
chest  wall.  This  is  pleurisy — not  the  pop- 
ular fallacy  of  a  pain  in  the  chest. 

An  X-ray  picture  was  then  taken  of  the 
chest  on  the  side  affected.  The  solid  patch 
of  dark  in  the  negative  suggested  pneu- 
monia, but  from  the  stethoscope  examina- 
tion this  was  properly  interpreted  as  pus- 
pleurisy  or  "empyema." 

An  anesthetic  was  then  given  and  a  tiny 
needle-tube  was  pushed  into  the  pleural 
cavity  much  as  a  beer-keg  is  tapt,  the 
matter  and  pus  were  drained  away,  and  lo 
and  behold  a  second  X-ray  photo  showed 
a  large  watermelon  seed  in  the  child's  wind- 
pipe. 

This  was  removed  and  the  youngster  was 
soon  well  and  happy.  The  two  X-ray  pic- 
tures alone  would  not  have  been  enough  to 
make  a  correct  diagnosis.  The  stethoscope 
alone  would  not  have  done  so.  A  wonder- 
ful doctor  with  all  the  fulness  of  sound 
senses  could  not  have  done  so  without  the 
other  aids.  

UNIQUE     BATTERY  SIGNALING 
LAMP  WHICH  STRAPS  ON  HAND. 

While  the  ordinary  battery  flashlight  has 
proven  its  efficacy  in  many  instances,  an 
inventor,  August  Sundh,  has  devised  and 
patented  the  flashlight  signaling  and  il- 
lumination outfit  here  pictured.  In  his  pat- 
ent he  states  that  the  apparatus  is  intended 
and  especially  adapted  for  the  use  of  per- 
sons working  around  machinery  or  in  place 
where  portable  lights  are  used.  Also  it  is 
pointed  out  that  it  will  prove  useful  for 
automobiles  and  trainmen,  such  as  for 
signaling  purposes,  and  its  use  in  this  direc- 
tion is  illustrated  in  the  accompanying  view, 
where  the  autoist  is  shown  giving  a  night 
signal  that  he  is  about  to  turn  a  corner. 

The  device  is  quite  simple  and  merely 
comprises  a  leather  or  other  form  resem- 
bling a  glove,  which  'straps  on  the  hand  and 
at  the  wrist.  This  glove  contains  a  flap 
pocket  to  carry  a  small  flashlight  battery. 
Several  miniature  battery  lamps  are  dis- 
posed in  various  positions  at  the  back  of  the 
leather  mitt  as  the  illustration  discloses,  and 
the  circuit  between  the  battery  and  lamps 
is  closed  whenever  desired  by  pressing  on  a 
small  push-button  switch  secured  on  the 

inside  of  the  mitt. 


December,  1917 


THE  ELECTRICAL  EXPERIMENTER 


523 


CARRY  THIS  VACUUM  CLEANER 
ON  YOUR  BELT. 

We  think  vacuum  cleaners  have  been 
perfected  to  the  limit  in  this  country,  but 
here's  an  English  type  of  portable  electric 
"suction"  cleaner,  as  they  call  it  over  there, 


This  Electric  Vacuum  Cleaner  Straps  to  Your 
Belt.    It  Is  Light  in  Weight  and  of  Extreme 
Flexibility. 

that  will  do  real  pretentious  work,  and 
weighs  but  l1/?.  pounds.  It  is  really  one  of 
the  most  ingenious  vacuum  cleaners  de- 
veloped. A  man  can  work  right  along  with 
it  without  tiring  and  besides  it  is  especially 
adapted  to  cleaning  stock  on  shelves,  books 
in  libraries,  et  cetera. 

The  belt  type  electric  suction  cleaner,  by 
a  turn  of  the  switch  and  a  guiding  hand, 
sucks  out  the  dust  from  fixtures,  shelves, 
stock,  stationery,  machinery,  etc.,  in  a  jiffy. 


WHY  YOUR  WINTER  ELECTRIC 
LIGHT  BILLS  ARE  HIGHER. 

The  accompanying  chart  shows  just  why 
your  electric  light  bills  are  higher  in  some 
months  than  others. 

In  winter  you  depend  upon  artificial  light- 
ing nearly  three  times  as  many  hours  in 
each  24  as  in  summer. 

In  June  the  average  use  of  electric  light, 
in  a  residence,  is  2  hours  and  35  minutes 
a  day. 


This  is  perfectly  natural.  As  the  sum- 
mer days  lengthen,  the  "electric  light  hours" 
become  longer,  says  the  Society  for  Elec- 
trical Development.  So  on  until  January 
when  the  days  grow  longer  and  the  "elec- 
tric light  hours"  grow  shorter. 

There  are  other  reasons,  too,  why  your 
bills  in  fall  and  winter  are  larger  than  in 
the  spring  and  summer — good  reasons  that 
show  it  is  simply  the  result  of  the  season's 
changes ;  your  more  extensive  use  of  elec- 
tric light,  and  not  the  fault  of  the  electric 
light  company  at  all. 

When  summer  is  over,  vacations  are  over. 
Everybody  is  home  again;  more  rooms  are 
occupied ;  more  light  is  needed. 

Long  evenings — late  bedtimes.  The  out- 
side cold  keeps  us  indoors.  The  soft,  cozy 
glow  of  electric  light  makes  reading  a 
pleasure.  More  people  stay  home  on  this 
account.  The  newspapers,  magazines,  study 
or  a  good  book,  music  and  games  pass  the 
evening  all  too  quickly.  It  is  bed-time  be- 
fore one  knows  it ! 

More  entertaining  is  done — parties  at 
home  for  the  grownups  and  little  folks. 
Sometimes  the  house  fairly  radiates  with 
the  good  cheer  of  electric  light. 


she  probably  will  have  classes  at  the  Y.  W. 
C.  A.  to  teach  women  the  continental  code. 


RADIO-ACTIVE  LUMINOUS  COM- 
POUNDS AND  THEIR  DECAY. 

At  a  recent  meeting  of  the  Royal  So- 
ciety, Mr.  J.  W.  T.  Walsh  read  a  paper 
on  this  subject.  The  theory  of  destruc- 
tion of  "active  centers"  put  forward  by 
Rutherford  to  account  for  the  decay  of 
luminosity  of  radio-active  luminous  com- 
pounds leads  to  a  simple  exponential  re- 
lation in  the  special  case  of  a  compound 
of  constant  activity.  It  has  been  found 
for  radium  zinc  sulfid  compounds  that  this 
relation  expresses  the  observed  results  to 
a  sufficient  accuracy  over  short  periods  of 
less  than  200  days,  but  that  it  fails  to  do 
so  over  longer  periods,  such  as  500  days, 
the  rate  of  decay  of  luminosity  becoming 
gradually  slower  and  slower,  so  that  the 
brightness  tends  to  a  limiting  value  which 
is  not  zero.  The  present  paper  is  an  at- 
tempt to  find  a  luminosity  time  relation 
which  will  allow  of  the  prediction  of  the 
intimate  behavior  of  compounds  of  vary- 
ing composition 


ARTIFICIAL 
LIGHTING 
HRS.PER.MY 
JANUARY  6.53 

FEBRUARY  5-38 
MARCH  4.10 
APRIL 


AFTERNOON  »~°EVENING 

00  4:00  8:00 

OH  p.  M.  P.M. 


MAY 


JUNE 


3.48 
2.95 
2.55 
2.60 


JULY 
AUGUST  3.15 
SEPTEMBER  4.00 
OCTOBER  4.90 
NOVEMBER  6.18 
DECEMBER  6.85 


This  Chart  Shows  Just  Why  Your  Electric   Light  Bill  Runs 
Higher  in  Winter  Than  in  Summer.   Daylight  Is  Shorter  for  One 
Reason. 


In  December  the  average  use  of  electric 
light,  in  a  residence,  is  6  hours  and  50 
minutes  a  day. 


GRANDMA,  RADIO  EXPERT, 
VOLUNTEERS. 

A  grandmother  has  offered  to  conduct 
classes  in  wireless  telegraphy  in  St.  Paul. 
Mrs.  Fredricka  Bell,  58,  of  that  city, 
learned  to 
send  and  re- 
ceive by  wire- 
less from  her 
g  randson, 
Harland  Hall, 
now  at  the 
United  States 
navy  radio 
station,  D  u  - 
luth. 

Before  their 
station  was 
disman  tied 
she  "listened 
in"  and  heard 
messages 
from  all  parts 
of  the  coun- 
try. 

If  the  gov- 
ernment will 
grant  permis- 
sion   for  the 

erection  of  a  wireless  station  in  St.  Paul, 
Mrs.  Bell  says  she  will  teach  all  branches  of 
wireless  operating.    If  that  is  impossible, 


THERMOSTATIC  REGULATOR 
CONTROLS  RADIATORS. 

One  thermostat  will  control  a  number  o: 
radiators.  The  valve  and  thermostat  are 
connected  by  electric  wires  conveniently 
placed ;  the  operating  current  is  so  small 
that  it  is  hardly  perceptible  and  is  obtained 
from  the  lighting  circuit. 

The  opening  or  clos- 
ing of  this  circuit  oper- 
ates the  valve  or  valves 
connected  to  the  radia- 
tors in  the  room.  The 
thermostats  are  so  ar- 
ranged that  a  range  of 
30  degrees  can  be  ob- 
tained. 

It  may  be  necessary 
at  times  to  shut  steam 
off  the  radiators  in  or- 
der to  make  repairs  or 
in  case  certain  rooms 
are  to  be  unoccupied. 
The  makers  provided 
for  these  emergencies 
by  placing  a  valve  stem 
in  the  top  of  each  valve, 
which  may  be  operated 
by  a  key  which  is  fur- 
nished with  each  valve, 
to  close  the  valve  by  hand. 

In  the  thermostat  is  a  small  metal  dia- 
fram  capable  of  expanding  and  contract- 
ing. Within  this  diafram  is  sealed  a  small 
amount  of  a  volatile  liquid.  The  slightest 
variation  of  temperature  either  expands  or 
contracts  this  diafram,  expanding  with  rise 
of  temperature  and  contracting  with  the 
fall  of  temperature.  This  diafram  actuates 
a  metal  strip,  thereby  opening  or  closing 
the  electric  circuit  as  the  case  may  be. 


Thermostat    f  o  r 
Regulating  Radl- 
ators. 


ELECTRIC  VALVE  GRINDER  FOE 
AUTOISTS. 

A  valve  grinder  fitted  with  an  electric 
motor  and  which  may  be  connected  to  any 
handy  lamp  socket  has  been  placed  on  the 
market  by  a  Michigan  manufacturer.  This 
grinder  develops  speeds  of  400  to  750  oscil- 
lations per  minute.  Between  the  mechanise; 
of  the  grinder  and  the  valve  a  flexible  con- 
tact is  provided  for  furnishing  a  light 
medium  or  heavy  pressure  upon  the  valve 

The  motor  supplied  with  this  grinde; 
operates  on  either  direct  or  alternating 


Motor-  Driven 


Valve    Grinder  for 
Engines. 


Auto 


current.  A  set  of  valves  may  be  re-ground 
in  an  average  time  of  thirty  minutes. 

ALLEN  P.  CHILD. 


524 


THE  ELECTRICAL  EXPERIMENTER 


December,  1917 


TELEGRAPH   LINEMEN   OF  THE 
FAR  NORTH. 

The  line  gang  of  a  telegraph  company 
operating  in  temperate  climes  may  think 


Instead  of  Spurs  These  Telegraph  Linemen 
of  Alaska  Wear  Snow-Shoes.  The  Poles  Are 
Tripods  Which  Rest  on  the  Ice  and  Snow. 

they  are  roughing  it  some,  when  the  snow 
and  chill  winds  begin  to  blow,  but  consider 
the  hardships  experienced  by  a  lineman  in 
such  frigid  countries  as  Alaska. 

The  accompanying  photograph  shows  line- 
gang  employed  in  stringing  the  wires  for  the 
government  railroad  telegraph  lines  in 
Alaska.  Instead  of  the  old  reliable  "climb- 
ers," or  spurs,  each  man  is  equipt  with  a 
pair  of  snow-shoes.  In  the  lower  right 
corner  of  the  picture  may  be  seen  a  string 
of  porcelain  insulators  and  a  coil  of  wire. 

Did  you  ever  stop  to  think  how  the  line- 
men place  their  poles  in  such  localities,  cov- 


ered the  year  around  possibly  with  snow  and 
ice?  "Dig  a  hole" — is  your  first  answer. 
Well  they  don't  use  poles,  not  as  we  know 
them  down  here  in  the  States.  In  the 
background  of  the  present  photo  can  be 
seen  an  Alaskan  telegraph  pole.  It  is  really 
a  tripod  formed  of  three  fir  poles,  nailed 
together  and  surmounted  with  one,  or  more 
insulators,  depending  upon  the  number  of 
circuits  in  use. — Photo  courtesy  Donald  Mc- 
Nicol. 


RADIO  FOR  WOMEN  AT  UNIVER- 
SITY OF  CALIFORNIA 

Wireless  telegraphy  for  women  is  to  be 
one  of  the  University  of  California's 
courses  and  the  new  study  has  been  added 
because  of  the  request  of  the  wife  of  an 
officer  stationed  at  the  Presidio.  It  is  the 
first  time  such  a  course  has  been  offered 
by  the  extension  department. 

The  class  will  be  held  at  the  Polytechnic 
high  school  in  San  Francisco  every  Sat- 
urday beginning  September  1.  There  are 
to  be  two  sections,  one  in  the  morning  and 
one  in  the  afternoon.  Professor  A.  L. 
Jordan,  head  of  the  department  of  science 
in  the  Polytechnic  High  School,  will  teach 
the  course  in  the  wireless  laboratory  of 
the  school  building. 


The  brush  does  not  revolve  but  contains 
an  open  center  thru  which  a  fan  located 
in  the  metal  container  draws  the  dust. 
The  dirt  is  loosened  by  the  brush  and  the 
fan  suction  catches  it  and  it  is  carried  on 
into  the  dust  bag.  A  special  attachment  is 
made  for  this  device  which  permits  the 
thoro  cleaning  of  the  buttons  in  the  tufting 
of  upholstery,  which  always  hold,  so 
tenaciously,  against  sweeping  a  great  quan- 
tity of  dirt. 

This  cleaner  may  be  used  as  well  for 
cleaning  draperies,  mattresses  or  uphol- 
stered furniture.  The  device  will  attach 
to  any  socket. — Photo  by  Allen  P.  Child. 


CLEANING    YOUR   CLOTHES  BY 
VACUUM. 

Here  is  a  device  which  will  keep  your 
clothes,  and  upholstered  interiors  of  auto- 
mobiles, et  cetera,  as  fresh 
and  clean  as  the  day  it  left 
the  respective  work  shops.  By 
using  the  principles  of  brush- 
ing and  suction  this  instru- 
ment thoroly  cleans  out  the 
dust  and  collects  it  so  that  it 
will  not  settle  again. 


Here's  the  Best  Way  to  Dry-Clean  Clothes — Use  an  Elec- 
tric Vacuum  Cleaner.    This  Method  Spells  Results  with 
the  Work  Left  Out. 


The  Subr 

THE    thousands    of    suggestions  and 
plans  presented  to  the  Naval  Con- 
sulting Board  for  assisting  the  Gov- 
ernment in  the  present  emergency  indicate 
the  patriotic  fervor  of  the  mass  of  our 
citizens. 

The  Board  makes  a  careful  examination 
of  every  proposal  presented.  To  facilitate 
this  work,  by  suggesting  the  elimination  of 
impractical  ideas,  the  Board  calls  to  the  at- 
tention of  those  who  desire  to  assist  it 
some  of  the  popular  misconceptions  as  to 
certain  fundamental  principles  which  are 
most  frequently  misunderstood  by  the  lay- 
man. 

A  careful  consideration  of  the  following 
statements  will  greatly  simplify  the  work 
of  the  Naval  Consulting  Board. 

Electro-Magnets  and  Magnetism 

The  Electro-magnet ,  the  Magnetic-needle , 
Permanent  Magnets  and  Magnetism  have 
been  carefully  studied  for  many  years ;  and 
the  laws  governing  their  application  may  be 
found  in  any  book  on  the  subject. 

Although  these  laws  are  generally  known, 
and  applied  in  a  practical  manner,  in  a 
multitude  of  devices  in  common  use,  even 
the  man  of  wide  experience  will  be  aston- 
ished at  the  limited  range  of  practical  effect 
of  electro-magnets  of  large  size.  For  in- 
stance, the  magnets  used  in  our  manufactur- 
ing plants  for  lifting  heavy  masses  of  iron 
or  steel  are  designed  to  exercise  maximum 
magnetic  effect,  and  for  operation  require 
a  very  considerable  amount  of  electrical 
energy;  yet  a  magnet  which  can  lift  twenty 
tons,  when  placed  in  contact  with  an  iron 
plate  of  that  weight,  will  not  lift  a  two- 

*PubIisht  by  Naval  Consulting  Board  of  the 
United  States. 


Larine  and  Kindred 

inch  cube  of  iron  or  steel  if  separated  front 
it  a  distance  of  two  feet.  Therefore  pro- 
posed devices  which  depend  on  the  attrac- 
tive power  of  magnets  for  their  operation 
in  deflecting  or  arresting  torpedoes,  mines 
or  submarines,  must  be  governed  by  the 
simple  laws  of  magnetism.  A  torpedo 
weighing  approximately  2,500  pounds,  and 
traveling  at  a  speed  of  25  to  45  miles  an 
hour,  will  not  be  deflected  to  any  practical 
degree  by  any  known  application  of  mag- 
netism ;  and  it  is  not  believed  that  an  enemy 
torpedo,  mine  or  submarine  will  ever  be 
found  in  a  position  to  be  interfered  with 
effectively  by  any  electro-magnetic  means, 
however  powerful. 

Electrical  Effects  in  General 

There  is  a  general  misconception  regard- 
ing the  "electrification"  of  water  and  the 
atmosphere.  There  is  no  known  method 
of  "charging  the  sea  with  electricity,"  or 
"shooting  a  bomb  of  electricity,"  or  of 
"charging  the  atmosphere  with  electrocut- 
ing current."  Suggestions  along  these  lines 
should  show  that  the  writer  has  made  re- 
search in  the  laws  governing  the  application 
of  electrical  energy  and  should  contain 
sufficient  proof  of  their  feasibility  to  in- 
sure serious  consideration. 

On  the  other  hand,  applications  of  the 
transmission  of  electrical  energy  by  means 
of  alternating  or  pulsating  currents — as 
used  in  wireless  systems,  for  example — be- 
long to  a  different  class  of  electrical  de- 
velopment. Inventive  genius  is  rapidly  im- 
proving apparatus  of  this  type  for  the  send- 
ing and  receiving  of  signals  and  messages, 
and  the  possibility  of  valuable  results  in 
this  field  is  unlimited. 


Problems* 

Protection  Against  Submarine  Attack 

This  subject,  which  is  occupying  the  pub- 
lic mind  as  is  no  other,  divides  itself  into  a 
number  of  problems,  the  most  important 
being  the  following: 

(a)  Means  of  discovering  the  approach 
of  a  hostile  submarine  and  locating  it  so  as 
to  permit  of  prompt  action  for  combating 
its  attack. 

(b)  Protection  of  cargo-carrying  ships 
by  nets,  guards  and  screens. 

(c)  Protection  thru  decreasing  the 
znsibility  of  vessels. 

(d)  Methods  of  destroying  or  blinding  a 
hostile  submarine. 

Submarines,  to  operate  most  effectively, 
must  approach  within  close  range  of  the  ves- 
sel which  is  intended  to  be  torpedoed.  The 
installation  of  offensive  weapons  on  the 
merchant  marine  has  increased  the  neces- 
sity for  the  utmost  care  being  exercised  by 
the  submarine  commander  in  remaining  un- 
seen by  the  officers  on  the  vessel  to  be 
attacked. 

Reports  from  abroad  indicate  that  in 
many  cases  submarines  must  have  remained 
along  certain  lanes  of  travel  for  periods  ex- 
tending into  weeks  of  waiting  with  the  ex- 
pectation of  torpedoing  certain  vessels. 
Under  certain  favorable  conditions,  where 
the  waters  are  less  than  200  feet  in  depth, 
a  submarine  might  lie  at  rest  on  the  bottom, 
and  if  equipt  with  sensitive  listening  de- 
vices attempt  to  detect  the  approach  of  a 
vessel.  As  soon  as  this  evidence  was  se- 
cured the  submarine  might  come  to  the  sur- 
face for  a  quick  observation  by  means  of 
the  periscope  and  in  this  manner  obtain  the 
proper  aim  which  would  be  required  to 
register  an  effective  hit. 

{Continued  on  page  579) 


December,  1917 


THE  ELECTRICAL  EXPERIMENTER 


525 


A  TELEPHONE  AMPLIFIER  THAT 
LEAVES  HANDS  FREE. 

The  telephone  as  it  stands  today  is  prac- 
tically a  perfect  instrument.  There  are 
times,  however,  when  the  hearing  efficiency 
is  far  below  normal.  At  such  times  you 
are  forced  to  ask  the  person  at  the  other 


A  New  Combined  Stereoscopic  and 
Fluoroscopic  Table 


This  Telephone  Amplifier  Is  a  Distinct  Ad- 
vance. It  Has  No  Direct  Connection  with 
the  Telephone.  You  Simply  Place  the  Re- 
ceiver on  the  Amplifier,  Leaving  Both  Hands 
.  Free. 

end  of  the  line  to  speak  louder,  some- 
times to  shout.  Even  then  you  don't  al- 
ways hear  clearly.  You  must  ask  him  to 
repeat  almost  every  word  that  is  said. 

The  new  telephone  amplifier  here  pic- 
tured, greatly  increases  the  hearing  ef- 
ficiency of  the  telephone,  all  harshness 
disappears  and  you  hear  the  voice  in  its 
natural  tones,  its  inventor  claims.  _  This 
is  accomplisht  by  the  accurate  tuning  of 
the  sound  chamber  in  the  instrument. 
This  sound  chamber  contains  no  mechan- 
ism to  get  out  of  order.  Just  as  a  sound- 
ing board  behind  the  speaker  increases 
the  voice  volume,  so  this  new  amplifier 
amplifies  the  telephone  sound. 

It  often  happens  that  while  telephoning 
you  wish  to  write  down  some  note,  con- 
sult a  catalog  or  read  a  letter  over  the 
'phone.  At  such  times  the  busy  man  will 
welcome  such  a  device. 


NEW  ELECTRIC  HEATER. 

A  novel  portable  electric  heater  for  home 
use  is  shown  herewith.  The  outfit  is  sub- 
stantially constructed  of  prest  steel,  on  the 
principle  of  the  portable  lamp.  A  steel  re- 
flector 9lA  in.  in  diameter  is  connected  to 
the  top  of  the  pedestal  by  a  hinged  joint 
which  is  adjustable  to  numerous  positions 
from  horizontal  to  diagonal,  upward.  This 
reflector,  which  is  of  a  special  parabolic 
design,  is  heavily 
plated  with  a  triple 
coat  of  highly  pol- 
ished copper.  The 
back  of  the  reflec- 
tor is  finished  in 
black  enamel.  Wire 
protecting  guards 
over  the  heating 
element  are  at- 
tached to  a  copper- 
plated  rim.  These 
guards  may  be 
easily  removed  for 
cleaning  the  re- 
flector or  changing 
the  heating  ele- 
ment, which  is  also 
easily  and  quickly 
detachable. 
The  heating  de- 
portable Electric  Heater,  ment  consists  of  a 
composition  core  1 
jn.  (2.54  cm.)  in  diameter,  around  which 
is  wound  high-resistance  wire.  The  wire 
is  first  wound  into  a  small  coil  and  then 
wound  around  the  composition  core,  giving 
a  large  amount  of  resistance  material  in  a 
small  area.  This  coil  will  attain  a  tempera- 
ture of  about  1,200  deg. 


The  new  X-ray  table  here  illustrated  has 
recently  been  evolved  by  a  New  York  con- 
cern. It  combines  a  tube  stand  with  table, 
which  may  be  used  for  stereoscopic 
roentgenography  and  also  for  fluoroscopy, 
both  in  either  the  horizontal  or  vertical 
position.  All  moving  parts  are"  so  poised 
and  balanced  that  they  may  be  smoothly 
manipulated  by  the  operator  without  as- 
sistance. 

Suspended  beneath  the  table  is  a  trocho- 
scope tube  box  running  on  ball  bearings 
and  so  designed  as  to  afford  ample  pro- 
tection from  rays  to  the  operator  and  pa- 
tient. A  special  feature  of  this  tube  box 
is  that  it  is  lined  with  opaque  rubber  and 
covered  outside  with  sheet  lead.  This  af- 
fords the  necessary  protection  from  rays, 
while  at  the  same  time  preventing  con- 
denser effect  and  resultant  tube  trouble. 
Another  innovation  is  that  of  a  vacuum 
reducing  switch  within  the  trochoscope  tube 
box.  By  this  means  the  operator  may  lower 
a  gas  tube  without  leaving  the  table.  Pro- 
vision is  also  made  for  the  use  of  the 


The  tube  stand,  which  is  a  part  of  the 
equipment,  travels  along  the  full  length  of 
the  table.  The  tube  bracket  is  well  counter- 
balanced and  is  free  to  swing  around,  away 
from  the  table  for  use  in  conjunction  with 
stretcher  or  other  apparatus. 

The  insulation  of  the  high  tension  cur- 
rent has  been  well  designed  and  is  such 
that  tubes  can  be  safely  worked  up  to  9 
inches  back-up  without  fear  of  sparking 
or  flashing  across  to  the  table. 

All  moving  parts  of  the  tube  stand  are 
carefully  graduated  so  that  records  can  be 
made  of  actual  positions  and  it  is  thus  pos- 
sible to  duplicate  these  conditions  if  nec- 
essary at  any  further  time. 


TO  TREAT  WOUNDED  WITH 
ELECTRICITY. 

Plans  developed  by  Dr.  Virgil  C.  Kin- 
ney, of  Wellsville,  N.  Y.,  one  of  the  best 
known  electro-therapists  in  the  country,  for 
the  formation,  equipment  and  administra- 
tion of  an  electro-therapeutic  hospital  unit 
to  be  establisht  in  France  for  American 


A  New  Stereoscopic  and  Fluoroscopic  Table  Which  Enables  the  Operator  to  Take  X-Ray 
Pictures  in  Either  the  Horizontal  or  Vertical  Position.    All  Parts  Are  Balanced  So  as  to  Be 

Easily  and  Quickly  Manipulated. 


Coolidge  tube.  The  movement  of  the  tube 
box  gives  a  large  field  of  vision  and  moves 
freely,  no  matter  in  what  position  the 
table  top  may  be  placed.  Attached  to  a 
bracket,  in  conjunction  with  this  tube  box, 
is  a  curved  support  which  suspends  over 
the  patient  a  fluorescent  screen  which  can 
be  twisted  around  in  any  direction  re- 
quired. This  fluorescent  screen  is  so  con- 
structed that  it  will  accommodate  a  plate 
holder  for  the  purpose  of  recording  cer- 
tain findings  immediately  by  utilizing  the 
rays  from  the  tube  beneath  the  table. 

The  stereoscopic  plate  changer  within 
the  table  top  is  a  feature  which  has  evi- 
dently received  considerable  care.  This 
works  very  smoothly  and  decisively  in  the 
horizontal  position  and  yet  works  without 
jar  when  used   for  vertical  stereoscopy. 


fighting  men,  were  indorsed  recently  at  the 
twenty-seventh  annual  convention  of  the 
American  Electro-Therapeutic  Association 
at  Atlantic  City. 

"The  remarkable  results  achieved  by 
European  belligerents  thru  physical  treat- 
ment for  crippled  and  nerve  racked  sol- 
diers, whereby  from  seventy-five  to  ninety 
per  cent,  of  invalided  men  so  treated  have 
been  returned  to  the  trenches,  should  stim- 
ulate the  whole  American  medical  profes- 
sion to  procure  similar  results  for  our  own 
fighting  men,"  Dr.  Kinney  said  in  pre- 
senting his  plan  for  Government  sanction 
of  electricity  and  light  in  place  of  surgery 
and  drugs  in  combating  battlefield  casual- 
ties. "This  large  percentage  of  cures  is 
practically  impossible  under  old  methods." 


326 


THE  ELECTRICAL  EXPERIMENTER 


December,  1917 


ELECTRIC    MOTORS    IN  NOVEL 
ROLES. 

A  large  new  Western  manufacturing 
plant  was  made  electrical  thruout ;  the  hu- 
man hand  and  brain  were  strengthened  by 
that  magic  force.   Because  the  ten  thousand 


wrench  by  screwing  down  nuts  at  the  rate 
of  100  per  minute,  and  with  a  cost  of  but 
one  cent  an  hour. 

It  is  difficult  for  the  eye  to  distinguish 
brass  from  iron  in  a  miscellaneous  assort- 
ment of  filings,  but  here  a  two  horse  power 
motor  rotates  an  electro- 
magnetic sorting  machine 
which  stacks  the  metal  up  in 
two  piles  at  the  rate  of  a  ton 
an  hour. 

The  heavy  job  of  handling 
the  coal  for  the  heating  plant 
is  easily  mastered  by  one  man 
with  an  electric  crane  at  the 
rate  of  twenty  tons  per  hour. 

The  second  photo  here  re- 
produced shows  one  of  the 
plant's  electric  storage  battery 
locomotives.  It  runs  anywhere 
and  everywhere,  without  hav- 
ing to  depend  on  rails  or  trol- 
leys. Fourteen  electric  trains 
of  this  type  are  operated  with 
speeds  up  to  fifteen  miles  per 
hour  attainable. 


The  Nuttiest  Job  Agoing.    One  Operative  with  This  Elec- 
tric Nut-Screwing  Device  Can  Screw  Down  Nuts  at  the 
Rate  of  100  a  Minute  at  a  Cost  of  1  Cent  an  Hour. 


horse  power  on  the  two  million  feet  of  floor 
space  was  to  be  electrical  the  production 
units  were  arranged  with  the  sole  thought 
of  making  an  unbroken  stream  of  opera- 
tion which  would  catch  the  raw  metal  in 
its  current  at  the  source  and  discharge  fin- 
ished valves  and  fittings  at  the  mouth. 

The  stream  idea  of  production  was  so 
perfected  that  now  the  work,  where  it  for- 
merly eddied  and  swirled,  flows  thru  with 
the  speed  of  a  mill  race.  Castings  are 
handled  red  hot, — sorted,  tumbled  and 
cleaned,  they  never  stop  until  delivered  to 
the  machine  room  still  warm.  The  very 
dust  that  comes  from  them  is  electrically 
collected  and  forms  a  valuable  by-product. 
Every  operation  is  animated  by  electricity. 

Even  the  day  of  the  spanner  wrench  has 


Fourteen  of  These  Busy  Electric  Locomotives  Haul  Heavy  Loads 
Up  to  15  Miles  Per  Hour  in  One  Industrial  Plant.  They  Operate 
on  Storage  Batteries. 


past.  Note  the  accompanying  photo  of  a 
curious,  unassuming  little  machine  used  in 
the  assembly  room  to  replace  the  old  hand 


MAGNETIC  SEPARATOR 
PULLEY  GREAT  TIME 
SAVER. 

By  Frank  C.  Perkins. 

THE  accompanying  illus- 
tration, Fig.  1  and  draw- 
ing Fig.  2,  shows  the  con- 
struction and  method  of  opera- 
tion of  the  magnetic  pulleys  de- 
velopment at  Milwaukee,  Wis. 
These  magnetic  pulleys_  are 
used  where  coarse  material  is 
to  be  handled,  where  the  iron 
to  be  extracted  is  limited  in 
quantity,  and  where  large 
capacity  is  important.  This 
equipment  is  used  extensively  to  protect 
crushing  and  grinding  machinery  from 
breakage  and  damage  due  to  "tramp"  iron 
found  in  various  kinds  of  material.  It  is  also 
used  for  removing  iron  from  material  for 
other  reasons,  both  mechanical  and  chemical. 

It  is  pointed  out  that  a  good  magnetic 
pulley  must  possess  qualities  not  generally 
given  sufficient  consideration.  To  be  effi- 
cient a  magnetic  pulley  must  be  strongly 
effective  at  any  point  on  the  surface  of  its 
face.  The  magnetism  must  be  distributed 
as  evenly  as  possible  and  not  be  short- 
circuited  within  the  pulley,  but  radiate  out- 
ward far  enough  to  be  attractive  thru  a 
heavy  conveyor  belt  and  any  thick  layer  of 
material  that  is  to  be  treated.  The  area  of 
the  surface  of  a  pulley  is  the  width  multi- 
plied by  the  circumfer- 
ence. To  thoroly  mag- 
netize this  whole  area  so 
that  it  will  exert  the 
strongest  possible  attrac- 
tive power  at  any  point, 
requires  experience  in 
designing  and  the  care- 
ful use  of  every  bit  of 
available  space  from 
shaft  to  circumference. 
The  pulley  is  built  of 
dynamo  steel  and  insul- 
lated  copper  magnet  wire. 

It  will  be  seen  that 
when  completed  it  is  prac- 
tically a  solid  mass  of 
metal  wire  and  insula- 
tion. The  energizing  coils 
are  carefully  protected 
from  all  possibility  of 
mechanical  injury  _  by 
heavy,  hard  brass  shields. 

When  in  motion  the  heat  is  rapidly 
dissipated  by  the  conveyor  belt,  so  that  it 
runs  practically  cool.    However,  all  ma- 


chinery is  more  or  less  subject  to  abuse 
by  careless  operators.  Any  magnetic  pul- 
ley left  standing  idle  for  a  long  time  with 
the  energizing  electricity  not  switched  off, 
an  dthe  pulley  partly  enwrapt  in  a  heavy 
rubber  belt,  is  liable  to  become  hot  enough 
to  injure  common  insulation. 

In  order  to  meet  such  contingencies  and 
to  avoid  all  possibility  of  damage  from  in- 
ternal heat  and  to  make  magnetic  pulleys 


Fig.  1.  The  Magnetic  Pulley  Separates  Mag- 
netic Substances,  Such  as  Iron,  from  a  Con- 
stantly Moving  Stream  of  Mixed  Material. 


as  near  "fool-proof"  as  possible,  the  very 
best  grade  of  fire-proof  magnet  wire  and 
fire-proof  insulation  is  used. 

It  is  urged  that  the  advantages  of  this 
separator  over  the  ordinary  drum  type  sepa- 
rator are  in  its  greater  magnetic  strength ; 
in  having  no  commutator  to  flash  and  cause 
trouble,  as  the  electric  circuit  is  not  broken ; 
and  in  having  no  brush  or  scraper  to  re- 
move the  attracted  iron. 

It  will  be  observed  that  the  operating 
principle  of  these  machines  is  very  simple. 
The  material  to  be  separated  is  fed  upon 
a  horizontal  (or  a  horizontally  inclined) 
belt  conveyor,  passing  over  a  magnetized 
pulley.  The  non-magnetic  material  falls  by 
gravity  from  the  brow  of  the  pulley  ver- 
tically into  a  suitable  receptacle  or  to  a 
conveyor  leading  to  final  delivery,  while  the 
iron  and  magnetic  materials  are  attracted 
and  held  firmly  against  the  belt  until  it 
is  carried  to  the  point  where  the  belt  leaves 
the  pulley  on  the  under  side  and  is  there 
discharged  back  of  a  partition  set  a  few 
inches  beneath  the  pulley  in  line  with  its 
axis  as  shown. 

It  may  be  stated  that  the  conveyor  is 
usually  a  rubber  belt  of  the  best  grade, 
heavy,  and  mechanically  strong  enough  for 
the  material  to  be  handled.    It  should  be 


Fig. 


2.     Sectional  and  Side  Views  of  New 
Magnetic  Separator  Pulley. 


made  endless,  so  that  no  dust  or  fine  ma- 
terial can  work  thru  at  the  splice.  The 
belts  are  usually  run  at  a  speed  of  about 
100  feet  per  minute. 


December,  1917 


THE  ELECTRICAL  EXPERIMENTER 


527 


ERECTING    OVERHEAD  MOTORS 
A  CINCH  WITH  THIS  DEVICE. 

Recently  quite  a  number  of  concerns  have 
been  using  a  unique  method  of  putting  up 
overhead  motors  which  permits  of  installing 


A    Time   and    Labor   Saver    Which  Every 
Electrician  Will  Appreciate,  Is  This  Latest 
Portable     Elevator     for     Erecting  Ceiling 
Motors. 

from  4  to  6  motors  in  the  time  formerly 
required  for  one.  This  method  simply  in- 
volves the  use  of  a  Revolvator,  as  it  is 
called,  to  elevate  and  hold  the  motor  in 
place  until  it  is  secured  to  the  ceiling.  It 
insures  absolute  safety  in  elevating  the  mo- 
tor and  does  away  entirely  with  scaffold- 

NEW  CORE  TYPE  TRANSFORMER 
DESIGN. 

The  new  core  type  transformers  here 
illustrated  have  concentrically  arranged 
high  and  low  tension  coils.  The  low-ten- 
sion winding  is  on  the  inside,  and  is  sepa- 
rated from  the  high-tension  winding  by  a 


ing,  special  heavy  platforms,  blocks  and 
falls  and  other  hoisting  arrangements  which 
were  formerly  used  for  this  purpose. 

The  Revolvator  as  may  be  seen  from  the 
accompanying  illustrations  is  a  portable 
elevator  or  tiering  machine.  It 
consists  essentially  of  two  up- 
rights or  elevator  guides,  an 
elevating  platform  and  a  re- 
volving base  which  can  swing 
around  on  its  ball-bearing  cen- 
ter like  a  turntable.  The  unit 
is  mounted  on  strong  truck 
wheels  and  is  equipt  with  a 
floor  lock.  A  motor  or  other 
article  to  be  raised  is  placed  on 
the  platform  when  down,  and 
by  means  of  a  crank  and  gears 
the  platform  is  raised  to  the 
level  desired.  In  elevating,  the 
load  is  sustained  independently 
of  the  crank,  for  a  ratchet  is  a 
provided  with  a  special  pat-  F 
ented  pawl  which  sustains  the  -=sdi 
load  at  every  point,  eliminat- 
ing all  possibility  of  the  plat- 
form being  dropt. 

The  illustration  shows  the  Why  Waste 
device  lifting  a  30  H.P.  1400  Keeper i  Gol 
lb.  motor  into  position. 

dielectric  strength,  are  unaffected  by  oil, 
and  are  in  every  way  the  best  barrier  de- 
vised for  insulation  between  high-voltage 
and  low-voltage  windings  of  concentrically 
wound  core  type  transformers.  Ample 
ventilation  is  secured  in  both  high-  and 
low-tension  windings  by  means  of  liberal 
size  ventilating  ducts. 

The  high-tension  coil  is  wound  with 
small  round  wire.  It  is  given  a  layer  of 
tape  to  bind  it  together,  after  which  it  is 
impregnated  in  gum.  Another  layer  of 
tape  is  then  applied,  followed  by  succes- 
sive dippings  in  varnish  and  dryings,  in 
order  to  fill  the  tape  and  give  the  coil  a 
good  gloss. 

The  low-voltage  coil  is  generally  wound 
in  cylindrical  or  rectangular  tube  form,  de- 
pending upon  the  shape  of  the  core  over 
which  it  is  to  fit.  It  is  generally  wound 
with  one  layer,  altho  it  is  not  uncommon 
to  have  two  layers  or  more,  if  proper 
ventilating  ducts  are  provided. 

For  the  lower  voltages,  the  core  is  some- 
times rectangular,  but 
for  the  high  voltages 
it  is  usually  cruciform 
in  shape.  Round  coils 
fit  well  over  a  cruci- 
form core  and  this 
form  is  adopted  for 
high  voltage  windings 
for  which  round  wire 
is  used. 

The  coils  are  braced 
at  the  ends  of  the 
columns  so  as  to  hold 
them  rigidly  in  place 
and  to  prevent  dis- 
tortion or  destruction 
in  case  of  short  cir- 
cuit. 


NOVEL  ELECTRIC  SELF-WINDING 
CLOCK. 

The  idea  of  a  clock  that  you  would  never 
have  to  wind  is  very  old,  and  men  have 
spent  their  fortunes  and  even  their  life- 


Several  Hours  Every  Year  Winding  Up  Clocks, 
Electric  Self-winding  Clock  Here  Shown  Will 
ng  Without  a  Grumble  for  a  Few  Cents  a  Year? 

times  in  attempting  to  perfect  and  market 
self-winders.  With  few  exceptions  these 
clocks  were  electrically  operated,  but  diffi- 
culties arose  in  each  attempt  that  seemed 
insurmountable,  such  as  cost  of  manufac- 
turing, poor  electrical  contacts,  batteries 
lasting  but  a  few  months,  and  usually  the 
construction  was  entirely  too  delicate  and 
complicated  for  practical  purposes. 

You  never  have  to  wind  the  electric 
self-winding  clock  here  illustrated.  The 
works  or  movements  are  standard  time- 
keepers with  the  added  attraction  of  be-, 
ing  wound  electrically  by  two  standard 
sized  dry  batteries  which  fit  neatly  in  the 
cases.  The  batteries  will  run  from  a  year 
to  eighteen  months,  and  new  ones  can  be 
easily  installed  by  anyone.  The  style 
shown  is  supplied  in  mahogany  and  meas- 
ures 13"  wide,  10"  high  and  has  a  5"  cop- 
pered dial. 


NEW  PUSH  BUTTON  WORKS  / 
WHEREVER  TOUCHED. 

Here  is  the  latest  in  push  buttons.  The 
entire  top  is  movable  so  when  it  is  prest 
at  any  point  the  contact  is  made.  The 
button  shell  is  finished  in  black  enamel,  and 
the  top  is  a  black  composition,  making 
a  neat  and  attractive  article.  If  you  have 
an  electric  horn  on  your  car  this  button 
will  enable  you  to  operate  it  easier. 


New  Core  Type  Transformers  with  Concentrically  Arranged  High 
and  Low  Tension  Windings. 

heavy  insulating  barrier  of  Bakelite-Mi- 
carta  in  the  form  of  tubes.  These  tubes 
are   strong    mechanically,    have    a  high 


DIVISION  CRE- 
A  T  E  D  TO 
HANDLE  ARMY 
RADIO. 

Creation  of  a  radio 
division   under  the 
chief  signal  officer  of 
the  army,  to  handle 
radio  matters  for  both 
the    aviation  section 
and  the  signal  corps 
proper  was  announced 
on  July  17,  by  the  war  department.  Major 
Nugent  H.  Slaughter,  reserve  corps,  is  de- 
tailed to  take  charge. 


This  Push  Button  Works  no  Matter  Where 
Touched. 


EFFECT  OF  MOON  ON  WIRELESS. 

Mr.  J.  W.  Cohen,  a  wireless  expert,  states 
that  while  stationed  in  the  tropics  for  sev- 
eral years  as  a  wireless  operator  he  ob- 
served that  in  the  period  of  the  full  moon 
the  atmospheric  interferences  are  slight  and 
the  ether  seems  to  carry  the  wireless  waves 
with  less  absorption  than  when  the  moon  is 
in  its  quarter  periods.  With  the  full  moon 
he  could  receive  signals  from  stations  two 
hundred  miles  farther  away  than  when  the 
moon  was  in  the  first  and  last  quarters. 


528 


THE  ELECTRICAL  EXPERIMENTER 


December,  1917 


FLASHLIGHT  IN  FORM  OF  BOOK. 

The  accompanying  illustration  shows  one 
of  the  latest  novelties  in  pocket  flashlights, 
the  containing  case  being  made  in  the  form 
of  a  small  memorandum  book,  which  will 
just  fit  the  vest  pocket. 

It  is  equipt  with  special 
high  power  tungsten 
lamp  and  push  button 
on  the  side  in  the  usual 
manner.  An  efficient 
dry  battery  furnishes 
current  for  the  lamp 
and  can  be  easily  re- 
placed at  any  time. 

This  particular  form 
of  pocket  flashlight  will 
appeal  to  many  people 
for  the  reason  that  it 
does  not  look  like  a 
flashlight,  and  also  it 
serves  as  a  very  appro- 
A  F.ashllght  That  P»ate  gift  to  most  any- 
Resembles  a  Book.  one. 


LITTLE  THINGS. 

Little  drops  of  water, 

On  the  turbine  blade, 
Make  the  total  horsepower, 

Something  fierce  and  great. 

Little  volts  and  amperes, 
Flowing  thru  the  "grounds," 

Make  the  meter's  reading, 
Grow  by  leaps  and  bounds. 

Little  dots  and  dashes, 

Little  signals  grand,  , 
Span  the  mighty  oceans, 

And  the  busy  land. 

Little  shocks  of  tension, 

Little  battery  leaks, 
Make  the  'dabbler's"  verbiage, 
Emanate  blue  streaks. 

— By  Edward  Schultz. 


NEW    STEP-DOWN    TOY  TRANS- 
FORMERS. 

The  toy  transformers  here  illustrated  will 
operate  ordinary  toys  such  as  small  train 
outfits,  small  motors,  etc.,  from  the  ordinary 
lighting  circuit.  The  transformer,  shown 
at  Fig.  1,  has  a  voltage  range  of  from  3 
to  30  volts  in  3  volt  steps — this  eliminates 
the  need  of  a  toy  rheostat  for  varying 
speeds.  It  is  provided  with  spring  clips 
for  secondary  terminals,  making  it  possible 
for  boys  to  quickly  and  accurately  connect 
up  their  toys.  There  are  no  binding  posts 
to  become  loosened  or  nuts  to  get  lost.  The 


curs  after  short  usage  in  many  toy  trans- 
formers. It  has  a  capacity  of  30  watts,  or 
2  amperes  at  18  volts. 

For  the  operation  of  large  sized  toys  and 
for  other  purposes  requiring  varying  volt- 
ages, the  same  concern  supplies  the  Auto- 
matic Cut-Out  Transformer  shown  at  Fig. 
2.    For  the  operation  of  electrical  toys  and 

J      In  the  January  "E.E."  g 

p|  The  January  number  of  The  Elec-  g 
g  trical  Experimenter  will  be  a  rec- 
IB  ord  breaker.  Don't  miss  it  friends,  p| 
Hi  It  will  be  replete  with  science,  elec-  g 
1H  tricity,  wireless  and  mechanics.  Do  g 
g  you  know  that  thousands  of  our  sol-  g 
g  diers  and  sailors  "over  there"  as  well  g 
IB  as  "over  here"  look  forward  eagerly  g 
p|  to  the  monthly  arrival  of  the  "E.E."?  g 
g  //  they  read  it  to  learn  the  newest  g 
g  things  in  electrical  and  radio  science,  g 
g  why  not  you?  And  don't  forget  to  g 
g  remail  this  magazine  when  you  are  g 
g  thru  with  it.  See  notice  on  front  g 
g  cover.  For  the  January  issue,  among  =J 
g  other  attractions  we  offer:  §§j 
p|  "The  Electric  Depth  Bomb — Terror  g 
g  of  the  Submarine,"  by  F.  R.  Lewis,  jj 
g  Military  Expert.  g 
g  "The  Electron— Just  What  It  Is"—  g 
g  a  remarkable  treatment  of  the  sub-  ^ 
g  ject  with  some  wonderful  photo-  p| 
g  graphs  by  Prof.  R.  A.  Millikan.  _  pj 
g  Baron  Miinchhausen's  New  Scien-  g 
g  tific  Adventures,  by  Hugo  Gernsback.  g 
g  "Machine  Shop  Kinks  for  Ama-  jj 
g  teurs" — a  new  series  for  the  practical  jj 
g  man,  by  Samuel  Cohen.  g 
g  "The  Home  Treatment  of  Tuber-  g 
p|  culosis  with  High-Frequency  Cur-  g 
g  rents" — a  most  valuable  article  by  an  g 
g  aut  h  o  r  it  y — Dr.  Frederick  Finch  g 
g  Strong,  M.D.  g 
g  "An  Electrical  Entertainment  de  g 
g  Luxe,"  describing  a  host  of  unusual  g 
g  and  instructive  experiments  as  pre-  p| 
g  sented  by  Mr.  William  J.  Hammer,  g 
g  "Ham"  Aerials — A  wireless  tale  g 
g  with  a  kick,  by  W.  J.  Howell.  g 
g  Detail  Construction  of  a  Damped  g 
g  and  Undamped  Wave  Receptor.  With  jj 
g  full  working  drawings  by  F.  Mac-  g 
g  Murphy.  g 
Bl  A  Neiv  Electrical  Time  Recorder,  = 
PJ  by  H.  Hartman,  C.E.  g~ 
g  The  First  Edison  Electric  Light  g 
Station — with  some  interesting  photos,  g 


experimental  work,  the  automatic  second- 
ary cut-out  not  only  protects  the  trans- 
former from  short-circuits  and 
over-loads,  but  it  eliminates  any 
danger  of  injury  to  toys  or  appa- 
ratus in  circuit.  It  is  said  to  be 
very  positive  in  its  action.  It  has 
a  capacity  of  125  watts,  or  5 
amperes  at  25  volts  maximum. 


ufacturer  has  devised  the  simple  battery- 
saver  illustrated. 

The  invention  consists  of  a  latch  device 
which  is  made  to  attach  to  the  hook  switch 


m 

Fig.  2 

Fig    1,  Right,  30  Watt  Toy  Step- Down  Transformer; 
Fig.  2,  Left,  125  Watt  Step- Down  Transformer. 


special  construction  of  the  voltage  regulat- 
ing lever  insures  good  contact  at  all  times — 
this  prevents  sparking  at  contacts  which  oc- 


BATTERY  SAVER  FOR 
TELEPHONES.  • 

On  rural  telephone  lines  there  are 
often  times  when  subscribers  desire 
to  "listen  in,"  as  for  example,  when 
market   and   weather    reports  are 
being  issued  from  the  central  ex- 
change.   This  "listening  in"  habit 
is  a  great  battery  consumer  and  to  eliminate 
it,  but  at  the  same  time  preserving  the 
farmer's  joy,  a  progressive  telephone  man- 


Thls  "Battery  Saver"  Telephone  Attach- 
ment Permits  One  to  Listen  in  on  a  Line 
Without  Wasting  Battery  Current. 

escutcheon  plate  on  the  left  side  of  the 
instrument.  When  the  receiver  is  removed 
from  the  hook  the  lever  springs  up  but  is 
caught  half-way  by  the  bent  finger  of 
the  battery-saver  latch.  In  this  position  the 
circuits  of  the  telephone  are  connected  so 
that  the  user  may  hear  but  not  talk;  the 
transmitter  is  not  connected  to  the  battery 
and  no  current  is  consumed. 

If  the  person  using  the  telephone  wishes 
to  talk  he  presses  the  latch  back  as  in 
illustration  herewith.  This  disengages  the 
hook  switch  lever  and  allows  it  to  resume 
its  upward  movement  to  the  full  operated 
position.  When  the  lever  is  in  this  posi- 
tion the  battery  is  connected  to  the  trans- 
mitter and  telephone  may  then  be  used  for 
talking  purposes. 


A  MOTOR-DRIVEN  MILK  TESTER 
FOR  DAIRYMEN. 

This  is  a  machine  for  rapidly  and  ac- 
curately determining  the  percentage  of  but- 
ter fat  in  milk  and  milk  products,  such  as 
cream,  skim  milk,  buttermilk,  etc.  A  definite 
quantity  of  the  liquid  to  be  tested  and  a 
definite  quantity  of  sulfuric  acid  are  thoroly 
mixed  in  the  special  bottle  provided  with  a 
graduated  neck.  The  object  of  adding  the 
acid  is  to  dissolve 
all  the  solids  in  the 
milk  except  the  fat. 
Its  strength  must  be 
proper  for  this  pur- 
pose, say  about  1.82 
specific  gravity.  This 
bottle  is  then  rotated 
at  sufficient  speed  so 
that  the  centrifugal 
force  generated 
throws  the  lighter 
part  of  the  liquid,  in 
this  case  the  butter 
fat,  up  into  the  neck 
of  the  bottle,  where 
its  percentage  of  the 
total  amount  may  be 
read.  Such  a  machine  is  nominal  in  cost 
and  saves  much  trouble  and  work  for 
dairymen. 


Motor-driven  Milk 
Tester. 


AMONG  the  hundreds  of  new  devices  and  appliances  publisht  monthly  in  The  Electrical  Experimenter,  there  are  several,  as 
a  rule,  which  interest  you.  Full  information  on  these  subjects,  as  well  as  the  name  of  the  manufacturer,  will  be  gladly 
furnisht  to  you,  free  of  charge,  by  addressing  our  Technical  Information  Bureau. 


December,  1917 


THE  ELECTRICAL  EXPERIMENTER 

A  Revolving  Electric  Christmas  Tree 

By  JOHN  T.  DWYER 


529 


FOR  those  experimenters  who  have  not  a 
storage  battery  or  whose  homes  are  not 
equipt  with  a  110  volt  house  circuit,  it 
is  a  difficult  matter  to  rig  up  an  electrical 
Christmas  Tree  display,  even  with  only  six 
or  eight  lamps,  as  for  efficient  results,  it 
generally  takes  about  a  half  dozen  dry  bat- 
teries at  the  least,  and  at  the  present  "war 
prices"  this  is  prohibitive  to  the  average 
"mucker".  However,  the  hook-up  here 
shown  not  only  possesses  several  novel 
features  but  can  also  work  well  on  as  low 
as  six  batteries— two  for  illuminating  the 
lamps  and  the  other  four  for  running  the 
motor.  This  is  made  feasible  by  the  fact 
that  only  one  light  is  brought  into  the  cir- 
cuit at  a  time  and,  as  the  revolving  of  the 
tree  by  means  of  the  motor  (see  Fig.  1) 
automatically  makes  and  breaks  the  circuit 
to  each  lamp  alternately,  the  result  is  a 
charming  "twinkling"  effect,  which  is  very 
pleasing  to  the  observer. 

While  the  drawings  are  practically  self- 
explanatory,  a  few  remarks  concerning 
some  of  the  details  may  make  them  even 
more  readily  understood.  Regarding  the 
two  wheels  in  Fig.  1,  these  act  as  a  smoother 
bearing  for  the  revolving  tree  and  may  be 
obtained  from  either  an  old  pair  of  roller 


RADIO  BETWEEN  SAYVILLE  AND 
HAWAII. 

The  navy's  new  wireless  station  at  Pearl 
Harbor,  Hawaii,  has  a  radius  of  five  thou- 
sand miles,  and  its  opening  on  September 
29th,  was  signalized  by  an  exchange  of 
messages  with  the  station  at  Sayville,  Long 
Island.  When  the  stations  now  building 
in  the  Philippines  are  completed  com- 
munication between  Washington  and  the 
Philippines  can  be  carried  on  with  only 
one  relay  by  way  of  Honolulu. 

The  Pearl  Harbor  equipment  makes  it 
the  most  powerful  radio  station  in  the 
world.  It  is  one  of  a  chain  of  high  power 
radio  stations  under  construction  by  the 
Navy  Department.  The  principal  stations 
completed  in  the  chain  are  at  Arlington, 
near  Washington,  at  Darien,  in  the  Canal 
Zone,  and  at  San  Diego.  The  remaining 
stations,  at  Cavite,  Philippine  Islands,  Guam 
and  Tutuila,  will  be  completed  in  the  next 
two  months.  The  outfits  include  three 
masts  at  each  station  to  support  the  aerial, 
each  mast  being  of  steel  and  self  supporting. 
The  apparatus  is  of  the  Poulsen  arc  type, 
which  is  standard  in  stations  of  the  high 
power  chain.  Suitable  and  comfortable 
quarters  are  provided  for  the  personnel  of 
each  station. 

Wireless  telegraphy  has  been  wonder- 
fully developed  since  the  experiments  made 
by  officers  of  the  United  States  Signal 
Corps  during  the  Civil  War.  These  began 
with  the  use  of  water-courses  to  carry  the 
current.  Aerial  telegraphy  was  then  at- 
tempted and  demonstrated  to  be  practicable 
for  short  distances  in  experiments  whereby 
messages  were  transmitted  from  one  height 
to  another  across  valleys  in  the  Cumber- 
land Mountain  region.  As  late  as  the 
period  of  the  Spanish  War  it  was  possible 
for  Dewey  to  debar  the  Philippines  from 
communication  with  the  outside  world  by 
cutting  an  ocean  cable — a  feat  which  can- 
not be  repeated,  for  progress  in  electrical 
science  has  been  going  forward  with  electric 
rapidity  since  the  spring  of  1898,  and  the 
world  is  now  in  a  new  age,  the  age  of  wire- 
less telegraphy. 


skates  or  else  discarded  furniture  castors. 
The  axle  on  which  they  turn  passes  thru 
the  stem,  or  trunk  of  the  tree,  and  has 
soldered  to  it  the  main  wire  in  the  circuit. 
The  metal  disc  or  washer  shown  in  Fig.  2, 
can  be  made  from  the  bottom  of  a  tin  can 


purpose  of  regulating  the  speed  of  the 
motor,  a  rheostat  of  the  small  coil  type 
available  on  the  market,  should  be  used, 
and  if  the  reader  has  not  this  instrument,  he 
may  readily  construct  a  simple  one  in  a  few 
minutes  by  referring  to  back  numbers  of 


METJ1L 
WHEtzL- 


A70TOR 


LAMPS 


BRUSHES 


RHEOSTAT 

Km 


BATTERY 


® 


BATTER) ^ 

■///,. ///////. 


B  ALL  BEARING  OR  MARBLE 


The  Electrical  Xmas  Tree  Can  Be  Made  Twice  as  Charming  by  Arranging  It  to  Revolve 
in  the  Manner  Illustrated.    The  Groups  of  Lamps  Blink  on  and  off  Alternately,  Giving  a 
Most  Beautiful  Effect  That  Will  Please  Kiddies  as  Well  as  Grown-ups. 


but  must  present  a  flat  surface.  The  com- 
mutators, of  course,  are  preferably  of  brass 
and  it  will  be  noticed  that  one  is  connected 
directly  to  the  battery  while  the  other  acts 
as  a  closing  switch  between  the  upper  and 
lower  contact  points.  These  latter  are  sim- 
ply round  brass  headed  tacks,  hammered 
into  the  tree  and  their  number  depends  on 
how  many  lamps  are  employed.    For  the 


the   Electrical   Experimenter  magazine. 

The  wiring  diagrams  are  shown  in  Fig. 
3.  Provided  that  the  tree  is  a  small  one, 
say  not  over  4  ft.  in  height,  a  toy  motor 
will  be  strong  enough  to  revolve  it  freely. 
For  the  purpose  of  cutting  out  the  lighting 
circuit,  as  during  the  day-time,  without 
however  interfering  with  the  motor,  a 
switch  may  be  inserted  as  shown. 


530 


THE  ELECTRICAL  EXPERIMENTER 


December,  1917 


How  to  Use  High  Frequency  Currents  in  the 

Treatment  of  Disease 

By  Dr.  FREDERICK  FINCH  STRONG. 
Lecturer  in  Electrotherapeutics,  Tufts  Medical  School,  Boston 


NOW  that  the  exigencies  of  war 
have  temporarily  suspended  the 
activities  of  amateur  Radiotele- 
graphers,  many  of  those  possess- 
ing transmitting  outfits  are  using 
them  for  the  experimental  study  of  the 


phenomena  of  High  Frequency  currents. 

In  the  Electrical  Experimenter  for 
May,  1917,  the  writer  described  the  con- 
struction of  a  Tesla  D'Arsonval  high-fre- 
quency outfit  made  from  standard  "Wire- 
less" apparatus,  consisting  of  a  ^  or  Yz 
K.W.  transformer  with  glass  plate  con- 
denser and  oscillation  transformer,  the 
latter  used  as  a  series  inductance  to  obtain 
various  effects  from  the  Tesla  coil,  or  as 
a  "D'Arsonval  Solenoid"  for  obtaining  the 
"Diathermic"  and  "Auto-condensation"  cur- 
rents so  valuable  in  the  treatment  of  certain 
diseases. 

Many  excellent  results  can  be  obtained 
from  high-frequency  treatment  adminis- 
tered by  those  who  have  little  or  no  knowl- 
edge of  medicine.  A  physician's  advice 
should  always  be  obtained  before  undertak- 
ing the  treatment  of  any  serious  case,  but 
the  amateur  may  safely  employ  moderate 
doses  of  Tesla  currents,  and  even  mild 
diathermy  and  autocondensation,  provided 
he  makes  himself  reasonably  familiar  with 
the  elementary  principles  of  electrothera- 
peutics* 

In  a  few  States  there  is  a  law  prohibiting 
the  therapeutic  use  of  electricity  by  any  but 
licensed  physicians,  but  even  this  would 
not  apply  to  treatments  given  gratuitously 
by  amateurs  to  relatives  or  friends.  A  num- 
ber of  the  writer's  former  pupils  have 
become  successful  practising  electrothera- 
peutists,  altho  they  are  not  physicians. 
Most  of  them  wisely  refrain  from  the  use 
of  the  sinusoidal,  Galvanic  and  static  cur- 
rents ;  these  belonging  more  to  the  field  of 
the  electro-medical  specialist. 

A  simpler  and  cheaper  apparatus  than  the 
one  described  in  the  May  issue  of  this  jour- 
nal will  give  all  the  varieties  of  therapeutic 
high-frequency  currents   that  may  safely 

_  •  The  new  edition  of  the  writer's  book,  "Essen- 
tials of  Modern  Electrotherapeutics,"  now  in 
press,  gives  all  needed  information,  with  an  alpha- 
betical list  of  various  diseases  and  the  method  of 
treating  them  electrically. 


be  used  by  the  amateur.  It  is  made  up  as 
follows : — 

Transformer, — Any  standard  K.W. 
radio  transformer  (E.  I.  Co.,  Clapp-East- 
ham,  Thordarson,  etc.) 

Condenser, — Standard  wireless  glass  plate 


condenser,  one  section  of  .005  microfarad ; 
two  sections  of  .01  m.f.,  each  in  series  will 
be  safer. 


Fig.  1.    A  Simple  Form  of  Fixt  Spark  Gap, 
Found  Very  Satisfactory  for  High  Frequency 
Outfits. 

Inductance  Coil,  ("D'Arsonval'' 
solenoid),  thirty  turns  No.  12  bare  copper 
wire,  wound  around  a  wooden  cage  8"  in 
diameter.,  *4"  between  turns. 

Spark  gap, — Adjustable  series  gap,  made 
as  shown  in  the  diagram,  Fig.  1.  The  spark- 
ing surfaces  are  of  copper,  turned  in  annu- 
lar or  concentric  grooves  as  described  in  a 
previous  article-  Copper  washers  of  J4" 
and  1"  diameter,  are  slipt  alternately  on  an 
8-32  machine  screw,  and  form  the  heat  radi- 
ating wings.  The  further  construction  and 
operation  of  the  gap  is  indicated  in  the 
drawing. 

Tesla  Coil, — Identical  in  winding  to  that 
previously  described,  viz., — secondary — on 
a  2"  diameter  paper  mailing  tube  wind  480 
turns  of  No.  34  S.  C.  C.  magnet  wire  (40 


turns  to  the  inch ;  12"  winding,  1"  margin 
on  each  end).  Slip  the  secondary  into  a  4" 
mailing  tube,  center  accurately  by  means  of 
three  corks  in  each  end,  seal  one  end  by 
standing  coil  on  end  in  a  shallow  pan  filled 
with  melted  resin,  and  when  cold  fill  the 
annular  space  between  tubes  with  a  mixture 
of  beeswax  (yellow)  one  part,  to  resin,  5 
parts.  Wind  primary,  consisting  of  six 
turns  "Magneto"  cable  (which  can  be 
bought  for  five  cents  a  foot)  around  center 
of  outer  tube ;  turns  spaced  l/2"  apart.  Sec- 
ondary leads,  of  magneto  cable,  should  be 
connected  to  the  outer  posts  of  the  writer's 
"triple  terminals."  One  arrangement  of  the 
complete  apparatus  is  shown  in  Fig.  2.  The 
triple  terminals  greatly  facilitate  the  thera- 
peutic use  of  the  Tesla  Currents,  and  also 
afford  an  opportunity  for  studying  differ- 
ent forms  of  the  high-frequency  discharge. 
The  actual  terminals,  A  and  C,  are  formed 
of  two  moulded  high-tension  insulators, 
surmounted  by  2"  brass  bed  balls,  (known 
to  the  furniture  trade  as  "brass  vases")  ; 
thru  terminal  A  slides  a  brass  rod  having 
a  rubber  or  hard-wood  handle  on  the  outer 
end,  and  a  3"  flat  brass  disc  on  the  inner 
end.  Terminal  C  is  similar  but  has  a  small 
brass  ball  on  the  inner  end  of  the  sliding 
rod.  A  "Dummy"  terminal,  B,  is  mounted 
as  shown,  midway  between  the  actual  ter- 
minals. By  closing  the  gap  between  the 
brass  discs  and  opening  that  between  the 
balls  B  and  C,  an  arc  discharge  is  obtained, 
while  by  closing  gap  B  C,  and  separating 
the  disc  electrodes,  the  discharge  forms  a 
beautiful  purple  brush  or  "effluve." 

In  giving  treatments  the  patient  is  seated 
on  a  folding  condenser  pad  of  thin  fibre 
of  Bakelite,  Fig.  4,  backed  with  copper  or 
tin  foil  to  which  is  attached  an  insulated 
cord  connected  with  terminal  C.  The 
operator  will  require  a  set  of  vacuum  elec- 
trodes, Fig.  5,  a  metal  hand  electrode 
formed  of  an  eight-inch  length  of  V/A" 
nickeled  brass  pipe,  "effluve"  electrode  made 
from  the  gong  of  an  old  electric  bell 
screwed  on  the  end  of  a  hard-wood  handle, 
and  two  pieces  of  sheet  block  tin  3"  x  3"  x 
1/32"  with  insulated  conducting  cords 
soldered  to  their  corners,  Fig.  6.  The  con- 
denser-pad can  be  obtained  from  any  elec- 
tro-therapeutical supply  house,  as  also  the 
vacuum  electrodes  and  other  materials. 

For  ordinary  general  treatment  to  pro- 
mote nutrition,  increase  circulation  and 
elimination — a  treatment  of  value  in  almost 
any  condition  of  impaired  health — the 
balls  and  discs  are  widely  separated  and 


Fig.  2.  Assembly  of  Apparatus  In  the  Au- 
thor's  High   Frequency  Therapeutic  Outfit. 


December,  1917 


THE  ELECTRICAL  EXPERIMENTER 


531 


the  patient  is  seated  on  the  condenser  pad 
connected  to  the  terminal  C.  Open  the 
spark  gap  until  a  vacuum  electrode  lights 
up  when  held  about  a  foot  from  the  pa- 
tient: this  shows  that  the  body  is  being 
charged  inductively  to  a  high  potential,  the 
charges  alternating  some  1,500,000  times  per 
second.  The  patient  feels  nothing  and  is 
absolutely  insulated  from  all  electrical  con- 
nection with  the  apparatus,  yet  hot  sparks 
can  be  drawn  from  any  part  of  the  body 
showing  that  the  whole  organism  is  being 
subjected  to  a  rapidly  alternating  molecular 
massage,  which  has  the  effect  of  increasing 
all  the  vital  functions  without  acting  as  a 
stimulant.  In  other  words  the  treatment 
tends  to  bring  the  patient  into  a  normal 
condition,  but  it  has  no  more  effect  upon  a 
perfectly  healthy  person  than  pouring 
water  into  a  pail  already  full.  This  is  the 
reason  why  high  frequency  treatments  may 
be  safely  given  by  those  who  are  not  phys- 
icians, whereas  all  other  forms  of  thera- 
peutic currents  act  as  stimulants  or  counter- 
irritants  and  must  be  employed  with  pre- 
cise knowledge  and  discrimination. 

The  condenser  treatment  as  described 
above,  is  usually  given  for  about  fifteen 
minutes  after  which  the  bulb-shaped  vacuum 
electrode  is  applied  for  a  few  minutes  over 
the  spine  and  solar-plexus.  It  is  applied 
either  directly  to  the  surface  of  the  body 
or  thru  one  thickness  of  clothing.  The  in- 
sulating handle  of  the  vacuum  electrode  is 
connected  to  the  middle  post  B,  in  Fig.  2, 
and  after  turning  on  the  current  and  plac- 
ing the  electrode  on  the  patient,  the  discs 
A  and  B,  are  closed,  being  opened  again 
before  lifting  the  electrode  from  the  sur- 
face of  the  body :  if  this  is  not  done  painful 
sparks  will  pass  from  the  glass  electrode 
to  the  patient.  In  treating  obstinate  cases 
of  recurrent  neuralgia,  chronic  rheumatism 
and  partial  paralysis,  this  vacuum  sparking 
treatment  is  often  beneficial,  but  it  is  rather 
unpleasant  for  most  cases.  A  milder  form 
of  this  counter-irritant  effect  is  obtained  by 
using  the  vacuum  electrode  over  two  or 
three  thicknesses  of  clothing;  it  must  be 
moved  rapidly  from  place  to  place,  other- 
wise the  skin  might  be  blistered. 

For  sedative  effects  and  to  reduce  local 
inflammation  and  congestion,  the  vacuum 
electrode  should  always  be  applied  directly 


> 


to  the  skin  or  mucous  membrane ;  this  ap- 
plies to  such  conditions  as  acute  rheuma- 
tism, neuritis,  tonsilitis,  etc.,  an  acute  "cold 
in  the  head"  (coryza)  can  often  be  aborted 


around  the  metal  "pipe"  electrode  connectec 
to  the  upper  turn  of  the  coil,  the  curren: 
is  turned  on  and  the  spark-gap  opened  unti 
a  pleasing  sensation  of  warmth  is  felt  flow 


DEWS/1T/OA/ 


Showing  How  a  Patient  Is  Given  the  High  Frequency  "Eflluve"  or  Spray  Treatmem 
The  Patient  Sits  on  a  Folding  Condenser  Pad  Placed  in  the  Chair. 


in  one  treatment  by  the  above  technique, 
using  the  vacuum  electrode  over  the  nose 


Fig.  5.    Various  Forms  of  High  Frequency 
Treatment   Electrodes.     They  Are  Made  of 
Glass. 


Figs.  4  and  6.    Condenser  Pad  Used  for  Giv- 
ing Auto-Condensation  Treatment  and 
Auxiliary  Tin  Electrode. 

and  the  thin  slender  vacuum  electrode  in 
the  nasal  cavity. 

In  treating  skin  diseases,  such  as  eczema 
and  acne,  where  we  wish  to  avail  ourselves 
of  the  antiseptic  and  tonic  effects  of  the 
"effluve,"  we  connect  the  effluve  electrode  in 
place  of  the  vacuum  electrode,  close  the 
discs  and  gradually  approach  the  bell  of  the 
electrode  to  the  patient  until  a  full,  blue 
violet  effluve  plays  upon  the  surface  to  be 
treated  (see  Fig.  3).  To  obtain  the  best 
effluve  effects  several  turns  of  the  tuning 
coil  should  be  used  in  series  with  the  Tesla 
primary  (see  article  in  May  issue).  The 
effluve  is  also  valuable  as  a  general  tonic  in 
sluggish  conditions  of  the  digestive  system, 
also  in  nervous  depression  and  functional 
nervous  diseases. 

For  the  relief  of  abnormal  arterial  ten- 
sion—  ("high  blood-pressure"),  and  in  the 
treatment  of  arteriosclerosis,  as  well  as  in 
conditions  involving  excess  of  uric  acid,  we 
employ  "D'Arsonval  autocondensation."  To 
obtain  this  current  we  short-circuit  the 
Tesla  primary  by  means  of  the  single- 
throw  switch,  and  attach  the  condenser  pad 
to  the  lowest  turn  of  the  "Solenoid"  or 
tuning  coil.    The  patient  clasps  both  hands 


ing  up  the  patient's  arms.  In  all  regula: 
therapeutic  high-frequency  outfits,  a  hot 
wire  milliamperemeter  is  placed  between  tht 
patient  and  the  machine.  This  is  not  neces- 
sary in  connection  with  the  above  describee 
apparatus,  as  it  only  delivers  a  maximum 
of  800  milli-amperes  to  the  patient — at 
amount  well  within  the  limits  of  safety 
In  chronic  cases  autocondensation  should  br 
given  daily  in  twenty-minute  treatments 
This  treatment  should  never  be  given  imme- 
diately after  eating,  or  in  cases  of  "Bright': 
Disease,"  or  in  organic  heart  trouble.  Higl 
frequency  treatments  are  of  great  valut 
even  in  these  conditions,  but  they  shoulc 
be  applied  only  by  a  skilled  specialist. 

In  inflammation  following  acute  infec 
tion,  as  in  acute  bronchitis,  incipient  pneu 
monia,  etc.,  we  employ  "local  autocondensa 
tion"   or   "indirect   Diathermy."     In  thi' 
method  the  patient  sits  upon  the  pad  as  fo- 
autocondensation,  but  instead  of  the  meta 
handle  we  employ  one  of  the  plates  o: 
block  tin ;  this  is  applied  in  close  contac 
with  the  skin  over  the  affected  area,  cov 
ered  with  a  folded  towel  and  held  in  placf 
by  the  patient;  a  sensation  of  deep  penetrat 
ing  heat  is  felt,  and  relief  from  the  pair 
and  congestion  follows.    This  is  one  of  the 
most  valuable  methods  in  electrotherapeu- 
tics; were  it  available  for  the  general  prac- 
titioner, or  better  still,  in  the  patient's  home 
there  is  no  doubt  but  that  nine-tenths  oi 
the  cases  of  acute  local  infectious  disease 
could  be  aborted.    This  is  also  of  grea~ 
value  in  the  treatment  of  asthma. 

Statistics  show  that  one-seventh  of  ali 
recorded  deaths  are  due  to  Pulmonary 
Tuberculosis  ("Consumption,")  :  proper 
treatment  in  the  home  by  high  frequencr 
currents  would  greatly  increase  the  per- 
centage of  recoveries  from  this  dread  dis- 
ease- Dr.  Howard  Van  Renssellaer  of  tht 
Albany  Tuberculosis  Hospital  has  reportec 
«0%  of  cures  by  high  frequency  treatment 
and  an  even  higher  percentage  is  reportec 
by  Dr.  Alfred  Geyser  of  New  York  Th« 
writer  feels  that  this  subject  is  of  sufficient 
importance  to  be  treated  in  a  separate  ar- 
ticle, which  will  appear  in  next  month's 
Ulectrical  Experimenter  under  the  title 

"T5.err??m/  Treatment  of  Tuberculosis 
with  High-frequency  Currents." 


532 


THE  ELECTRICAL  EXPERIMENTER 


December,  1917 


w  RADIO  LEAGUE 


AMERICA 


H.  Gernsback,  Manager 


HONORARY  MEMBERS 

CAPT.  WH.G.  BUILARD,  U.S  N.  NIKOLA  TESLA. 
PROF  REGINALD  FESSENDEN .    DR  .  LEE  DE  FOREST. 

W.  H.  Kirwan,  Master  of  Radio  Relays 


The  Spirit  of  1917 


AMATEURS  of  America!    Read  the 
f\     accompanying  letter,  and  after  you 
y%    have  read  it,  read  it  again.    If  you 
«*-         are  a  red-blooded  American  Radio 
Amateur,  to  whom  the  honor  of 
his   country  means   anything  at  all,  you 
cannot  fail  to  see  the  moral  contained  in 
Mr.  Leland  Allen's  let- 
ter. 

Here  is  a  young  man 
with  wife  and  children 
dependent  upon  him,  and 
who  as  a  rule  would  be 
readily  excused  from 
serving  with  the  colors. 
But  no  !  HE  realizes  for 
what  ideals  this  country 
is  fighting.  He  is  will- 
ing to  do  his  share, 
nay,  lay  down  his  very 
life  if  need  be  to  make 
this  world  free  for  de- 
mocracy. He  knows  that 
this  is  not  just  an  ordi- 
nary small  war.  He  don't 
think  about  letting  the 
other  fellow  do  the. 
work.  Far  from  it.  He 
does  know  that  if  we 
don't  fight  the  enemy 
"over  there,"  we  surely 
will  fight  him  over  here, 
just  as  sure  as  the  sun 
will  rise  tomorrow. 

Now  fellow  amateurs 
what  are  YOU  doing 
about  it?  Does  it  not 
make  you  blush  when 
you  read  Mr.  Allen's 
letter,  while  you  sit  se- 
curely in  your  home,  fooling  away  your 
time?  Where  is  your  far-famed  and  oft' 
boasted  American  fighting  spirit?  Don't 
you  single  fellows  with  no  real  ties  to  keep 
you  home,  feel  small  and  ashamed  of  your- 
selves, when  the  married  men  come  for- 
ward, while  you  do  nothing?  Red-blooded 
Americans!  Yes,  where  are  they?  Hiding 
in  the  security  of  their  homes.  And  you 
pride  yourselves  as  being  the  descendants 
of  Washington  and  Lincoln!  Both  would 
blush  with  shame  were  they  to  return  today 
to  witness  the  spectacle  of  seeing  only  1,000 
Amateurs  out  of  a  possible  300,000  step  for- 
ward to  do  their  share  for  their  glorious 
country.  For  up  to  this  writing  only  about 
one  thousand  amateurs  have  shown  their 
willingness  to  help  their  Government  by 
becoming  operators  in  either  the  Army  or 
the  Navy.  Just  think !  1,000  out  of  300,000 ! 
What  a  disgrace  to  the  Radio  Fraternity! 

Could  you  blame  the  officials  in  Washing- 
ton after  the  conclusion  of  the  war  if  they 
said : 

"We  have  before  us  the  question  of  re- 
opening the  Radio-amateur  stations.  The 
American  amateurs  demand  of  their  Gov- 
ernment the  free  use  of  the  ether.  They 
had  it  before  the  war.  Of  all  countries 
in  the  world,  the  American  amateurs  had 


the  greatest  liberties.  These  liberties 
were  given  them  so  that  in  case  of  war 
the  Government  would  be  assured  of  ob- 
taining an  unlimited  number  of  operators. 
Now  let's  see  what  happened.  The  war 
came  and  the  Government  wanted  opera- 


HoDbbittp  Sight  anil  gating  (Company 


LELAND  ALLEN.  I 
WOODBINE. 


October  4th  1917. 

The  Radio  League  of  America. 
233  Fulton  St. 
New  York  City. 
Gentlemen :- 

You  will  please  find  enclosed  the  membership  blank  ,  filled  and  signed 
I  have  a  family  to  support  but  I  will  start  the  ball  rolling  and  send  in  my 
membership  card.  If  dear  old  Uncle  Sam  wants  me  I'll  be  there. 
Of  all  the  single  fellows  that  had  wireless  sets  ,  and  to  have  hung  off  this 
long  when  the  chance  of  thier  life-time  is  now  calling  them. 
The  government  ought  to  have  been  over-run  with  applications. 
But  if  need  be  ,  I  will  step  forward  ,  leaving  behind  a  wife  and  two  babies. 
Yours  for  Radio, 


tors.  It  needed  some  25,000  of  them. 
Rather  a  small  percentage  out  of  a  pos- 
sible 300,000.  Did  the  Government  get 
these  operators  after  sending  out  distress 
calls  thru  the  daily  press  and  thru  the 
technical  publications?  Not  much.  Either 
there  are  no  Radio  amateurs  in  the 
United  States  or  their  Americanism  has 
gone  bankrupt.  In  either  case  let's  wash 
our  hands  of  the  matter.  If  the  amateurs 
don't  need  their  Government,  the  Gov- 
ernment does  not  need  the  amateurs,  who 
at  best  are  a  nuisance  anyway.  Seems 
to  us  that  these  fellows  don't  believe  in 
the  doctrine  of  50-50.  Their  religion  is 
90-10 — ninety  for  themselves  and  a  bad 
ten  for  their  Government!  Move  that  we 
"can"  the  whole  tribe!  The  Amateur 
Radio  Stations  STAY  CLOSED.  Finis!" 

Now  Amateurs  this  is  exactly  what  will 
happen  if  the  situation  does  not  improve, 
soon.  No,  we  are  not  as  a  rule  calamity  howl- 
ers, but  we  can  see  ahead  of  the  times,  and 
frequently  we  have  our  ears  to  the  ground. 
We  know  what's  coming,  but  you  appa- 
rently do  not.    If  you  did,  you  would  come 


forward  and  sign  your  application  blank. 

Now  before  you  close  this  magazine,  go 
into  your  den  where  no  one  watches  you 
and  have  speech  with  yourself.  Just  say: 
"What  on  earth  is  wrong  with  me  any- 
way? Why  am  I  such  a  confounded,  slow- 
moving,  unappreciative,  unimaginative, 
good-for-nothing  radio- 
slacker?  Yes  why?  I 
am  a  husky  brute, 
know  all  about  Radio 
that's  worth  knowing, 
(and  then  some),  eat 
three  square  meals  a  day, 
loaf  a  good  deal,  act  the 
great  knows-it-all  when 
the  girls  are  around,  but 
my  patriotism  has  gone 
bluey.  Of  course  no- 
body suspects  this 
but  myself.  When  I  am 
with  the  gang  I  can  wave 
the  Stars  and  Stripes  and 
shout  "Amerika  iiber 
Alles"  as  well  as  the  best 
of  them !  To  be  sure  I 
mean  to  sign  that  old 
"Radio  Honor  List" 
blank  sometime.  But  why 
hurry?  Let's  first  see 
how  many  others  sign  it. 
Then  sometime  I'll  sign 
it  too. 

"Yes,  let  the  other  fel- 
low be  the  patriot  first. 

"But  why  do  I  always 
put  things  off  till  tomor- 
row ?  Why  ?  I  r  e  a  1 1  y 
ought  to  know  better. 
This  procrastination  of 
mine  has  given  me  nothing  but  trouble  all 
my  life.  It  has  been  my  greatest  single 
liability — my  great  handicap.  Some  day  it 
will  cost  me  my  neck  ....  Damn  some 
day  ....  damn  tomorrow  ....  I'll  sign 
that  blank  NOW!" 
P.  S.    And  be  sure  to  mail  it  tonight!! 


=  RADIO  WRITERS  —  ATTENTION  !  !  ! 

=  Can  you  write  radio  articles  dealing 

=  with  the  practical  problems  of  wireless 

=  operating?      We   can   use   some  good 

—  papers  on  such  subjects  as  "the  tuning 

—  of  radio  transmitters";  "the  use  of  the 

—  wave  meter,  including  its  application 
EE  to  measuring  the  frequency,  wave 
■  -  length  and  decrement";  "operation  of 
=  commercial  transmitting  and  receiving 

sets";   "the  operation   of  army  trunk 

EE  sets";    "improved    ways    of  receiving 

=  undamped    wave    signals,"    also  new 

—  ideas  and  short-cuts  for  learning  the 

—  codes.     We  pay  well   for  all  articles 
accepted.     Help  yourself,  your  maga- 

=  zine  and  your  country. 


December,  1917 


THE  ELECTRICAL  EXPERIMENTER 


533 


ftaoto  &oIl  of  Honor 


Editor's  Note.  For  obvious 
reasons,  the  city  addresses 
of  the  applicants  listed  be- 
low have  been  left  out.  Only 
the  name  of  the  Radio 
Amateur  as  well  as  the 
State  in  which  he  resides 
have  been  publisht.  Every 
applicant  listed  in  these  col- 
umns has  pledged  his  ser- 
vices to  his  country  as  a 
radio  operator. 

AH  honor,  and  our  sin- 
cere congratulations  to 
every  young  man  whose 
name  appears  here. 


Alabama 

Harold  L.  Mitchell 
Paul  Draper 

Arkansas 

Miles  Sharp 

J.  Walter  Moore 

Arizona 

W.  N.  McKnight 
W.  H.  Buntin 

California 

Hugo  Pearson 
H.  J.  Schnarr 
James  Glenn 
Floyd  Hollister 
E.  E.  Twombly 
Arthur  Munzig 
John  Stevens 
Wm.  G.  Harris 
William  Siegel 
Joseph  A.  Axen,  Jr. 
Howard  R.  Lee 
Jack  Rosenberg 
Geo.  Shong 
David  Spowart 
Roy  A.  Wilkins 
Gilbert  A.  Trosper 
G.    A.  Trosper 
A.  W.  Martin,  Jr. 
Chas.  F.  Filstead 

Colorado 

Elliott  Buchanan 
Ed.  B.  Landon 
D.  P.  Deich 


Connecticut 

Leslie  A.  Didsbury 
Bud  Hartman 
Howard  Simons 
C.  S.  Keatinge 
Walter  Payne 
Arthur  Barney 
Ed.  J.  Heffernan 
Suno  Larson 
F.  A.  Mulvihill 
Wm.  F.  Murray 
William  H.  Mansfield,  Jr. 
Adelmer  R.  Bryon 
E.  Gaynor  Brennan 

Delaware 

R.  A.  Gentman 

District  of  Columbia 

Edwin  A.  Emerson 
Barton  White 


Florida 

R.  C.  Holtzclaw 

Georgia 

Edward  Merritt 
C.  D.  Short 
Geo.  Hamilton 

Idaho 

Floyd  Taylor 
Loy  Haeerman 
Robert  Eldridge 


Illinois 

Folke  Martin 

Wm.  Schrand 

H.  N.  Johnson 

Otto  Meyer 

H.  E.  Bergae 

E.  A.  Blum 

O.  L.  Keller 

C.   N.  Larson 

Richard  Rea 

Earl  Pratt 

B.  F.  Chiles 

Jos.  H.  Chapman 

Rowell  Herrick 

Wm.  J.  Langan,  Jr. 

Marvin  Messing 

Leo.  L.  Hamilton 

Marcus   Potter,  Jr. 

Stanley  G.  Jones 

Ira  F.  Coon 

Lawrence  Armantrout 

P.  J.  McGee 

R'.  J.  Iversen 

Verner  Hicks 

T.  S.  Lively 

Chas.  Bare 

Kenneth  Baldwin 

Chas.  D.  Thomas,  Jr. 

Tesse  D.  Weast 

R.  C.  Kingsley 

H.  O.  Reitsch 

Chas.  Coe 

Harold  Sever 

Carmi  Edward  Miller,  Jr. 

E.  Jerome  Wolff 
Walter  S.  Franseen 

Iowa 

Odell  Smith 
Leroy  F.  Bremmer 
Paul  D.  Anderson 

G.  Windenburgh 

F.  Starzl 

Homer  D.  White 
P.  A.  Stover 
Ray  Farmer 
John  B.  Martin 
Carl  A.  Mathiasen 
Glenn  F.  Dunfee 

B.  Harold  Miller 
Leland  Allen 

R.  H.  Smyth 

Indiana 

Robt.  H.  Douglass 
Richard  Boharavoz 
W.  H.  Keller 
Clarence  F.  Kramer 

H.  A.  Mcllvaine 

C.  A.  Powers 
Leland  Miller 

G.  Bloom 

H.  Schlemmer 
Tom  Frazer 

Kansas 

Carl  Paulsen 

D.  I.  Shepherd 
J.  L.  Smith 

W.  T.  Wilshusen 


Kentucky 

Elby  Becker 
Lawrence  O.  Davis 
E.  A.  Hahn 
Oscar  Ward 

Maine 

Elwell  C.  Dyer 
Walter  Marr 
Walter    G.  Stone 
C.  A.  Rounds 
Emery  D.  Austin 
Harold  Wilson 
Reginald  J.  Curtis 

Maryland 

Wm.  Bernhard 
Wm.  A.  Needs 
Allan   C.  Poore 
Paul  A.  Burrier 

Massachusetts 

Thos.  G.  Waldie 

Wm.  Lewis 

G.   A.  Werner 

John  Fouhy 

M.  Stearns 

Arthur  Bremilst 

Frank    De  Visscher 


fiollis  L.  Gray 
H.  W  Troop 
Johi.    B.    Paine,  Jr. 
Wm.  Hartwell 
Manuel  Casta,  Jr. 
H.  W.  Jonnson 
F.  D.  Sharpe 
Walter  J.  Morse 
Ed.  F.  McMahon 
Harold  Smeltzer 

D.  Meirowitz 

E.  H.  Raymond 
Edward  Dwyer 
Hugh  M.  Henry 
Fred  Snell 

David  H.  McDonald 

A.  J.  Smith 

A.  Chester  Clifford 

Willard  Staten 

Geo.  W.  Pettengill,  Jr. 

F.  J.  Lindsay 
Fred.  W.  Bowman 
O.  F.  Davis 
Louis  A.  Jaques 
F.  R'.  Pray 
Howard  Bauman 
Emery    A.  Millette 


Cecil  Randall 
Louis  A.  Frost 

Minnesota 

Chester  Kraft 
Nathan  Thon 
Alvin  R.  Matt  son 
Theodore  H.  Lutes 
Robt.  J.  Engler 
M.  Swanson,  Jr. 
Robt.  Hall 
M.  Bergstrom 
Sam  Wilkeson 

Missouri 

R.    L.  Coe 
E.  S.  Bodine 
Hall  Anderson 
Arthur  S.  Hughes 
Chas.  Albert  Pfisteres 
Irwin  Umbright 
Lawrence  Wilhelm 
A.  L.  Fluesmeier 
Lawlon  Andrews 
Joe  P.  Rynearson 


RADIO  AMATEURS!    IS  YOUR 
NAME  HERE? 

The  Editor  of  The  Electrical 
Experimenter  has  patriotically  pro- 
posed the  "Radio  Roll  of  Honor,"  the 
first  signatures  having  been  publisht 
in  the  November  issue.  Let  every 
Radio  Amateur  and  Expert  not  at 
present  engaged  on  work  for  the 
government  or  in  the  government 
service  sign  the  blank  on  page  571. 
Red-blooded  Americans,  it  is  the 
least  you  can  do.  Uncle  Sam  needs 
your  services  NOW !  not  next  year 
or  the  year  after  that.  He  is  calling 
for  tens  of  thousands  of  RADIO 
OPERATORS— not  thousands.  No 
other  country  in  the  world  treats  its 
fighting  men  better  than  the  United 
States.  The  food,  clothes,  and  pay 
are  right.  Advancement  is  rapid  and 
sure.  If  you  are  ready  to  help  your 
country  sit  right  down,  sign  the  ap- 
pended blank,  and  mail  it  to  us.  We 
will  record  your  name  for  next 
month's  "Radio  Roll  of  Honor"  and 
forward  the  blank  to  Washington. 
Come  on — "Buck  Up"  as  Tommy 
Atkins  says,  and  sign  up.  We  have 
got  to  have  thousands  of  names. 

The  Editors. 


H.  R.  Gurney 
Walton  Stockwell 
Francis  J.  Connelly 
Raymond  Gough 
Harry  Seifert 
Harold  Hatch 
Chas.    Robert  Calef 
Wm.  P.  Aldrick 
Abel  L.  Jewett 
K.  Hayden 
Howard  Allen 
Robt.  C.  Kingsley 
Wm.  G.  Mackay 

Michigan 

Howard  Peacock 
Samuel  Bortz,  Jr. 
Sam'l  R.  Colburn 
G.  E.  Flower 
Edw.  G.  Koch 
Geo.  L.  Whiting 
Carroll  S.  Miller 
T.  S.  Brown 
Leonard  E.  Paige 
Goodwin  Crinbie 
Harold  Hendel 
Thos.  H.  Boardman 


Montana 

Albert  Menke 
Jack  Richards 

Nebraska 

Chauncey  C.  Potter 
Everett  Wash 
Wilbur  Cramer 
Harley  Davis 
G.  A.  Gamble 
Richard  Jesse 
Lee  Nelson 
Harvey  Neuguist 

New  Jersey 

John  Arsics 
Lester  I.  Wiltse 
Henry  Brechle 
C.  M.  Blackford  3d 
Milton  Dreyfus 
Wm.  Gartner 
Halsey  W.  Kline. 
Leo  Kraemer 
C.  M.  Lindheimer 
Harold  Toland 


Lester  D.  Brierley 
Arthur  R.  Aldous 
Dave  Borduin 
W.  Arthur  Colledge 
Arthur  Kennedy 
Harold  Thompson 
John  Van  Orden 
E.  W.  Hunt 
Wm.  H.  Brunt 
L.  H.  Brandt 
Otto  A.  Unger 
Edward  T.  Warner 
Harry  Curtin 
Chester  R  Gernert 
Oscar  A.  Dohn,  Jr. 
Wm.  Goldstein 
M.  K.  Pillsbury 
Ed.  G.  Raser 
J.  L.  Scherer 
Robert  A.  Worley 
H.  C.  Fischer 
Fred  F.  Fuhrman,  Jr. 
Howard  Smythe 
Chas.  G.  Fritz 
R.  D.  Valentine 

New  Mexico 

Charley  Herman 


New  York 

Sydney  Maunder 
Herbert  Rexford 
H.  G.  Mulligan 
Geo.  Stephani 
Paul  Chambers 
Roland  H.  Conklin 
Edward  J.  Halch 

F.  J.   Reilly,  Jr. 

T.   E.  Merrihew,  Jr 
R.  T.  Searing 
H.  L.  Phillips 
Herman  Ziegler 
E.  C.  Wiendieck 
Albert  Bachelet 
Roderick  Flandeau 
Ed.  W.  Haag,  Jr. 
Geo.  S.  Brush,  Jr. 
Wesley  Seitz 
D.  S.  Catchim 
James  Beales,  Jr. 
P.  J.  Welcome 
Livingston  Welch 
Harold  Bradish 
Donald  Le  Fevre 
Wm.  E.  Schafer 
Wm.  Ehret 
Morris  J.  Almstead 
H.  S.  Barnes 
Abe  Frankel 
C.  W.  Gibbs,  Jr. 
Ira  Goldman 
A.  M.  Lindsay 
A.  G.  Loebs 
James  L.  Newbolt 
Leo  Charles  Essig 
Jack  S.  Morris 
H.  D.  Oakley 
Ed.  D.  Fitzpatrick 
Chas.  Nason 
Richard  Oram 
Stanley  L.  Cox 
Wilbur  P.  Wellington 
Clarence  Kerr 
Roland  F.  Rebyea 
Morgan  Thompson 
W.  E.  Gillette 
H.  G.  Hill 
H.  J.  Frahm 
C.  W.  Newman,  Jr. 
J.  R.  Richardson 
H.  T.  Kinsley 
A.  J.  Krynski 

G.  Ladermann 
A.   H.  Lang 
Howell  W.  Miller 
Walter  L.  Miller 
Harry  C.  Mills 
Chas.  Minter 

C.  A.  Muller 
A.  E.  O'Brien,  Jr. 
Chas.  Pierti 
Irving  Regan 
Herold  S.  Vincent 

Robinson,  Jr. 
Sam'l  Ruben 
Geo.  Schadt 
Max  Schaefer 
A.  Silverstein 
R.  J.  Smith 
T.  S.  Steiniger 

A.  Taylor 
Leonard  B.  Victor 
Carl  W.  Vollmer 
Wm.  Warren 
Chas.  R.  Weir 
Walter  Wiese 

B.  Wertheimer 


North  Carolina 

Jesse  W.  Hodges 
Wm.  A.  Campbell 
Lessesne  R.  Allison 
Chas.  W.  Clodfelter 


North  Dakota 

William  Warren 
Harold  W.  Ka  Dell 
Dean  Cottam 
Claude  B.  Phillips 
Herbert  T.  Hintgen 

Ohio 

John  Disser 
Geo.  R.  Wolfgang 
Fred.  Briggs 
Cyril  Harvey 
Howard  G.  Huddle 
Allen  Rose 
Leonard  S.  McMillen 
Orlin  Hibbett 
John  Washburn 
Harry  B.  Ogle 
R.  V.  Weimer 
Glenn  W.  Curtiss 
Starling  Yinger 
J.  M.  Westcott 
L.  E.  Russell,  Jr. 
E.  G.  Whitney 
Emil  Ostertag 
Kenneth  Gumm 
Lloyd  B.  Phillips 
R.  Smith 
Hillis  Berkey 
Perry  Weiser 
R.  C.  Husselman 
Fred  Schwartz 

Oklahoma 

Clarence  Selby 
Charles  Parkinson 


Oregon 

Graham  Henson 
O.  J.  Straney 
N.  J.  Van  Arnam 
Chester  B.  Beamer 
Clinton  Miller 
Robert  Lee  Stephen 

Pennsylvania 

Robert  Wolf 
Merle  Wetzel 
Ed.  Eisele^  Jr. 
John   J.  Gillen 
Floyd  T.  Gibson 
Carl  T.  Graner 
Robt.  Gonnelli 
Stanley  Gustof 
Howard  M.  Hill 
W.  H.  McCarter 
Eugene  McGowan 
J.  Wilson  Gray 
David  Schatz 
F.  Talone 
Alois  Ullmann,  Jr. 
Harold  K.  Wilsey 
Earle  E.  Baer 
Geo.  C.  Calvert 
A.  H.  Campbell 
Wm.  B.  Hanlon 
Ed.  G.  Hlawaiti 
H.  H.  Beatty 
Benton  A.  Weil 
Eugene  Cawley 
Ward  Stineman 
C.  E.  Knott 
E.  R.  Carlson 
E.  N.  Phillips 
C.  S.  Morgan 
Robt.  Shoop 
Geo.  D.  Pardee 
W.  S.  Shaler 
S.  W.  Huff 
Wm.  H.  Wagner 

Rhode  Island 

J.  W.  Whitmore 
H.  S.  Gates 
Adolph  H.  Mitchell 
John  Anderson,  Jr. 
Thomas  Saunders 
A.  H.  Mitchell 

South  Dakota 

Esli  H.  Daniels 
Tohn  A.  Miller 
Alfred  Shaw 


{Continued  on  page  571) 


i34 


THE  ELECTRICAL  EXPERIMENTER 


December,  1917 


Notice  to  All  Radio  Readers 

As  most  of  our  radio  readers  are  undoubtedly  aware,  the  U.  S.  Government  has  decided  that  all  Amateur  Wireless  Sta- 
tions, whether  licensed  or  unlicensed,  or  equipt  for  receiving  or  transmitting,  shall  be  closed. 

This  is  a  very  important  consideration,  especially  to  those  who  are  readers  of  THE  ELECTRICAL  EXPERIMENTER, 
for  the  reason  that  we  desire  to  continue  to  publish  valuable  articles  on  the  wireless  art  from  time  to  time,  and  which  may  treat 
on  both  transmitting  and  receiving  apparatus.  In  the  first  place,  there  are  a  great  many  students  among  our  readers  who  will 
demand  and  expect  a  continuation  of  the  usual  class  of  Radio  subjects,  which  we  have  publisht  in  the  past  four  years,  and 
secondly,  there  will  be  hundreds  and  even  thousands  of  new  radio  pupils  in  the  various  naval  and  civilian  schools  thruout 
the  country,  who  will  be  benefited  by  up-to-date  wireless  articles  treating  on  both  the  transmitting  as  well  as  receiving  equip- 
ment.   Remember  that  you  must  not  connect  up  radio  apparatus  to  any  form  of  antenna. — The  Editors. 


Some  Interesting  New  Radio  Apparatus 


THE  interesting  new  radio  apparatus 
shown  herewith  has  been  recently 
developed  by  Mr.  Melville  Eastham, 
the  well-known  radio  engineer,  and 
much  of  it  has  been  recently  em- 
jloyed  for  use  on  Government  radio  equip- 
ment.   The  apparatus  is  of  particular  in- 
erest  to  radio  experimenters,  as  while  it 


meter.  When  we  achieve  accuracy,  essen- 
tial in  any  wave  meter,  and  extreme  com- 
pactness and  portability,  we  have  an  in- 
strument peculiarly  adapted  to  some  uses, — 
such  as  tuning  up  transmitters  on  subma- 
rine-chasers, etc.  Within  the  wave  lengths 
adapted  to  it  the  wave  meter  shown  in 
Fig.  1  is  unapproached  in  convenience. 


a  circular  window  with  cross-hair.  The 
inductance  is  mounted  beneath  the  panel, 
out  of  sight,  together  with  the  variable  air 
condenser  and  the  body  of  the  hot  wire 
meter.  The  entire  instrument  is'  mounted 
in  a  strong  oak  box  which  measures  8^4 
by  5^2  by  Sy2  inches,  with  a  handle  for 
carrying;  the  total  weight  is  4%  pounds. 


Fig.  1.    New  300  to  1,000  Meter  Range  Direct- Reading  Wave  Meter. 
A  Hot  Wire  Meter  Indicates  Resonance. 
Fig.  2.    Laboratory  Style  of  Wave  Meter  Which  Is  Fitted  With  Thermo- 
couple and  Galvanometer,  as  well  as  Phones,  Detector,  Buzzer,  etc. 
Fig.  3.    Radio  Relay  Key  Good  for  5  K.  W.  Equipt  with  Emergency  Lever. 
Fig.  4.    Flame-Proof  Key  for  Use  on  Balloons  and  Aeroplane. 


Fig.  5.    Wave  Meter  of  Similar  Pattern  to 
that  in  Fig.  1,  But  Uses  'Phone  and  Detector 
'o     Determine     Resonance     Point.  Normal 
Range  200  to  2,600  Meters. 


Fig.  7.  Improved  Receiving  Variometer  Hav- 
ing Three  Windings,  Connected  to  a  Special 
Switch  Permitting  of  Series  and  Parallel 
Combinations  of  the  Coils.  Coils  Are  Wound 
Self -Supporting. 


Fig.  6.  A  Variable  Step  Inductor  for 
Use  in  Audion  Regenerative  Circuits. 
Coupling  Is  Possible  by  Placing  One 
Coil  Box  On  Another.  Has  No-End- 
loss  Switch. 


is  of  first  class  design  and  workmanship, 
the  cost  of  the  instruments  is  very  nomi- 
nal. 

A  correctly  designed  direct-reading  wave 
meter  is  unequaled  in  many  points,  conven- 
ience and  ease,  and  speed  of  readings  be- 
ing important  features  to  consider  in  all 
ordinary   classes   of   work   with   a  wave 


This  wave  meter  is  constructed  to  read 
from  300  to  1000  meters,  resonance  for 
transmitted  signals  being  indicated  by  a 
sensitive  hot  wire  meter.  For  use  with 
required  signals  a  simple  crystal  detector  is 
mounted  on  the  panel,  with  binding  posts 
for  'phones.  The  wave  lengths  are  read 
directly  from  a  scale  which  passes  beneath 


There  are  no  adjustments  to  be  made  at 
any  time — simply  hold  the  meter  a  few  feet 
from  the  helix,  and  on  the  maximum  de- 
flection of  the  hot  wire  meter,  read  the 
wave  length  directly  from  the  circular  win- 
dow. 

The  laboratory  type  wave  meter  shown 
(Continued  on  page  577) 


December,  1917 


THE  ELECTRICAL  EXPERIMENTER 


535 


BLIND  OPERATORS  IN  THE  GER- 
MAN ELECTRICAL  WORKS. 

The  authorities  in  Brandenburg,  Ger- 
many, have  been  endeavoring  to  find  oc- 
cupation for  men  who  have  lost  their  eye- 
sight, and  a  number  are  now  being  em- 
ployed in  the  Siemens-Schuckert  Electrical 
Works.  They  are  found  quite  serviceable 
for  such  work  as  gaging  small  parts,  stamp- 
ing numbers,  packing  small  articles  and 
testing  fuse  plugs  acoustically.  A  room  is 
given  up  to  their  working,  and  special  pre- 
cautions are  taken  in  the  location  and  fenc- 
ing of  machines  and  the  elimination  of 
sharp  projections  that  might  cause  injury. 
The  workers  are  paid  a  minimum  wage  of 
28  pf.  (about  7  cents)  per  hour,  but  some 
earn  as  much  as  55  pf..  (about  14  cents). 
It  is  stated  that  they  prefer  machine  work 
to  hand  work,  the  noise  of  the  machines 
being  apparently  a  useful  guide  to  the  prog- 
ress of  each  operation. 


DR.  L.  W.  AUSTIN  ON  THE 
AUDION. 

Results  of  observations  made  on  the  de 
Forest-Hudson  filament  Audion  at  the 
United  States  naval  radiotelegraphic  labor- 
atory are  cited  by  Dr.  L.  W.  Austin,  in  the 
Journal  of  the  Washington  Academy  of 


Island,  San  Diego,  Cal.,  weighs  about 
45  pounds,  and  it  has  covered  a  distance  of 
more  than  150  miles,  while  flying  at  an  ele- 
vation of  700  feet. 

Some  of  these  light  weight  aeroplane 
radio  transmitting  sets  utilize  a  buzzer  and 
"kick"  coil,  such  as  featured  by  Dubelier. 


NEW    JERSEY    RADIO  ASSOCIA- 
TION TO  TEACH  WIRELESS 
CLASS. 

The  South  Jersey  Association  Radio 
Class  opened  in  the  High  School  at  Col- 
lingswood.  N.  J.,  recently  with  a  large 
number  joining  the  wireless  telegraphy 
class,  including  seventeen  persons  who 
were  not  members  of  the  association. 
Harry  W.  Densham,  secretary  of  the  asso- 
ciation, is  the  permanent  instructor  and 
gave  the  first  lesson  in  radio  experiments 
and  wireless  telegraphy  at  this  meeting. 
Several  women  joined  the  class  and  it  is  ex- 
pected that  nearly  one  hundred  will  be- 
come members.  Those  who  desire  to  reg- 
ister and  for  information  'phone  or  write 
H.  W.  Densham,  410  Woodlawn  avenue, 
and  C.  Waldo  Batchelor,  president,  207 
Woodlawn  terrace.  Mr.  Densham  gives 
his  services  and  instruction  free  as  "his 
bit"  for  Uncle  Sam. 


BIG   RADIO   PLANT   PUT   UP  AT 
CAMP  DEVENS. 

A  portable  wireless  station,  said  to  be  the 
most  powerful  in  the  country,  is  being  set 
up  at  Camp  Devens,  Ayer,  Mass.,  and 
completed,  as  a  monument  to  the  zeal  and 
patriotism  of  a  group  of  college  men, 
scions  of  wealthy  families. 

Capt.  J.  J.  Fanning  is  the  skipper  of  this 
crew  of  signal  corps  experts,  crack  radio 
and  telegraph  operators,  mechanics  and 
electricians,  who  bear  the  label  of  301st 
Field  Signal  Battalion,  Reserve  Corps. 

Departmental  red  tape  having  interfered 
with  the  furnishing  of  their  equipment,  they 
bought  their  own,  and  have  erected  a  pole 
70  feet  high  on  which  the  antenna  will  be 
spread  to  intercept  messages  from  Panama, 
London  and  other  places,  and  also  Ger- 
man messages. 


PHONOGRAPH    TEACHES  WIRE- 
LESS CODE  QUICKLY. 

Perhaps  the  most  useful  application  of 
the  phonograph  to  the  radio  art  at  present 
is  its  adaption  to  the  teaching  of  the  Wire- 
less Code.  By  the  aid  of  new  records  in- 
vented by  Mr.  Walter  P.  Phillips,  author 
of  the  Phillips  code,  it  is  possible  to  use 
them  on  the  regular  home  talking  machine, 
and  learn  the  code  without  any  expensive 
apparatus. 

There  are  two  ways  of  learning  to  read 
by  sound.  The  old  way  was  to  have  the  letters 
very  slowly  made  with  dots  and  dashes  at 
long  intervals  apart,  and  painfully  guest 
out  by  a  combined  effort  of  the  intellect 
and  imagination.  But  the  letters  made  in 
this  manner  do  not  sound  as  they  do  when 
the  dots  and  dashes  are  placed  in  close 
connection,  as  the  pupil  must  eventually 
learn  to  read  them.  The  true  way  to  learn 
to  read  by  sound  is  to  follow  regular  and 
moderate  sending  from  a  written  or  printed 
slip.  In  this  way  the  letters  reach  the  ear 
as  they  will  always  sound,  and  it  is  not 
difficult  with  a  copy  of  the  message  being 
ticked  out  before  one  to  follow  it. 

The  phonograph  is  an  ideal  and  perfectly 
adapted  machine  for  this  purpose,  and  it 
hardly  can  be  realized  that  it  was  not  in- 
vented for  this  particular  purpose.  The 
code  records  come  in  a  set  of  eight  10-inch 
discs — one  lesson  on  each  side,  making  16 
lessons  in  all,  after  which  time  it  is  possible 
for  the  student  to  advance  rapidly. 

It  is  well  known  that  students  invariably 
copy  the  style  of  their  tutors.  Realizing 
this,  only  the  best  of  professional  men  have 
been  chosen  to  make  these  records,  and  the 


The  Phonograph  Has  Proven  Extremely  Valuable  in  Teaching  the 
Radio  Code. 


operator  chosen  for  this  task  holds  the 
Diamond  Medal  for  proficiency  in  the  art. 

These  records  are  the  best  means  of 
securing  practise  in  Radio  codes  at  a  very 
small  outlay,  and  I  earnestly  recommend 
every  student  to  investigate  the  merits  of 
these  records. — George  Holmes. 


The  Wireless  Class  Maintained  by  the  South  Jersey  Radio  Association  at  the  High  School 
in  Colllngswood,  N.  J.   This  Is  What  Every  Radio  Club  and  Association  Should  Do  to 

Help  Their  Country. 

Sciences.  The  gas  pressure  used  in  Audion 
detectors  is  generally  below  0.001  mm.  of 
mercury.  By  substituting  nitrogen  for  air, 
to  prevent  the  burning  out  of  the  filament, 
it  has  been  found  possible  to  construct  de- 
tectors at  all  pressures  up  to  that  of  the 
atmosphere.  The  action  at  3  mm.  is  en- 
tirely normal.  Local  oscillations  are  easily 
produced,  and  the  sensitiveness  is  fully  as 
great,  both  for  continuous  and  damped  sig- 
nals, as  at  the  usual  pressure.  At  10  mm. 
the  sensitiveness  is  about  normal,  but  local 
oscillations  are  more  difficult  to  produce. 
In  the  neighborhood  of  atmospheric  pres- 
sure no  local  oscillations  have  been  observed 
and  the  sensitiveness  to  spark  signals  is 
much  less  than  at  the  low  pressures.  The 
conditions  in  this  case 
would  undoubtedly  be 
much  improved  by 
bringing  the  elec- 
trodes closer  together. 
Even  with  the  ordi- 
narv  arrangement  of 
electrodes,  the  changes 
in  the  grid  and  plate 
currents  due  to  the 
incoming  waves  are 
similar  to  those  ob- 
served in  the  usual 
vacuum.  With  200 
volts,  the  plate  cur- 
rent amounts  to  20 
or  30  micro-amperes. 
Data  are  also  given 
on  the  effect  of  the 
D.  C.  voltage  between 
grid  and  filament  on 
grid  and  plate  signals. 


WIRELESS  SETS  ARE  LIGHT. 

One  of  the  wireless  sets,  employed  by 
the  United  States  Signal  Corps,  succeeded 
in  communicating  over  a  distance  of  119 
miles,  from  an  aeroplane,  weighs  only  60 
pounds.    Another  set,  developed  at  North 


536 


THE  ELECTRICAL  EXPERIMENTER 


December,  1917 


The  Audion  and  The  "Edison  Effect 

By  GEORGE  HOLMES 


MUCH  has  been  said  both  pro  and 
con  on  the  Audion  of  late  and  con- 
siderable litigation  has  taken  place 
between  various  claimants  for  the  discovery 
of  same.    This  naturally  has  set  our  vast 
numbers    of    amateur    and  professional 


The  Simplest  Form  of  "Edison  Valve,"  Hav- 
ing a  Platinum  Electrode  Mounted  Between 
the  Legs  of  the  Filament.  When  the  C.  P. 
Was  Raised  a  Current  Was  Found  to  Flow 
Thru  the  Galvanometer. 


radio  men  wondering  where  to  secure  their 
Audion  apparatus  and  as  to  what  will  de- 
velop that  will  place  this  instrument  on  the 
market  again  or  some  substitute  equally 
as  efficient. 

De  Forest  and  Fleming  both  have  certain 
claims,  it  is  true,  altho  it  has  been  shown 
that  both  their  types  of  bulbs  are  used 
differently  and  achieve  excellent  results ; 
especially  is  this  true  of  the  Audion. 

At  a  recent  meeting  of  the  Institute  of 
Radio  Engineers  at  New  York,  the  why 
and  wherefore  of  the  Audion  was  thoroly 
discust  and  the  fact  presented  that  the 
same_  could  be  used  as  an  oscillator  and 
amplifier,  whereas  with  the  Fleming  valve, 
it  was  impossible  to  do  this. 

Then  again  there  is  a  call  from  Mr. 
Meadowcroft,  Edison's  associate,  to  the 
technical  press,  to  the  effect  that  Mr. 
Edison  has  first  place  as  the  inventor  of 
the  principle  from  which  was  derived  the 
present  day  valve,  Audion  and  other 
hybrid  forms  of  vacuum  bulb  detectors. 

Looking  up  the  history  of  the  subject, 
the  writer  succeeded  in  locating  the  fact  that 
in  a  paper  presented  before  the  first  meet- 
ing of  the  Institute  of  Electrical  Engineers, 
way  back  in  1884,  there  was  shown  the 
principle  of  the  valve  as  discovered  by 
Edison,  and  bulbs  containing  third  members 
(electrodes)  were  displayed. 

Due  credit  must  be  given  to  Edison  for 
his  practical  improvements  of  the  incandes- 
cent lamp  and  it  seems  that  while  ex- 
perimenting on  this  device  with  various 
elements  that  the  following  phenomena 
were  noticed  and  recorded. 

It  is  not  my  object  or  purpose  to  make 
any  certain  claims,  only  to  give  the  readers 
a  light  on  a  very  obscure  point  as  to  the 
first  discovery  of  the  principles  of  the 
vacuum  valve.  Later,  with  certain  im- 
provements and  different  forms  of  elements 


the  present  day  valve  was  brought  out, 
but  it  seems  that  Mr  .Edison  should  receive 
credit  for  it  in  some  way,  altho  he  prob- 
ably had  no  conception  at  that  time  of  the 
application  his  principle  would  be  put  to. 

Referring  to  Fig.  1,  a  platinum  strip  or 
plate  (P)  will  be  seen  supported  between 
the  two  branches  of  the  usual  looped  fila- 
ment. The  posts  P  and  N  are  connected 
to  the  ends  of  the  carbon  loop,  and  O  to 
one  end  of  the  platinum  plate;  P  is  the 
positive  and  N  the  negative  terminal  of 
the  electric  source.  The  lamp  is  placed  in 
the  circuit  of  an  electrical  source  or  battery; 
the  current  will  then  flow  as  per  arrows. 
The  galvanometer  G,  has  one  of  its  ter- 
minals connected  with  the  positive  ter- 
minal P  and  the  other  with  the  platinum 
plate. 

Now,  it  was  proved  that  if  the  ordinary 
current  used  in  producing  incandescence 
is  passing  thru  the  filament,  no  unusual  ef- 
fects were  noticed.  But  if  the  current  is 
increased,  so  that  incandescence  is  raised 
above  normal,  for  instance  eight  candle 
power  to  twenty,  thirty,  forty,  fifty,  or 
perhaps  one  hundred  candle  power,  then 
the  needle  of  the  galvanometer  is  violently 
deflected  by  a  current  passing  thru  its 
coils. 

When  the  connections  were  reversed, 
that  is  to  say  the  galvanometer  terminal 


A  Similar  "Edison  Valve"  to  Fig.  1,  Except- 
ing That  Two  Auxiliary  Platinum  Plates  Are 
Used.    Galvanometer  Deflections  Were  Also 
Obtained  With  This  Arrangement. 


from  P  to  N  terminal  as  per  dotted  line, 
then  a  current  of  negative  polarity  flowed, 
but  greatly  reduced,  or  about  one  fortieth 
of  the  previous  flow. 

It  was  thought  at  the  time  that  a  Crookes' 
discharge  from  one  of  the  poles  might 
produce  an  electrical  bombardment  against 
the  plate,  each  molecule  taking  a  small 
charge  that  might  produce  the  effect  of  a 
current. 

Such  being  the  case,  if  we  conceive  a 
flow  of  molecules  passing  from  the  platinum 
electrode  to  the  heated  carbon,  then  the 
phenomenon  may  readily  be  explained  as 
a  Crookes'  effect,  since  we  can  regard  a 
current  flowing  in  a  parallel  circuit,  from 
P  to  N  thru  the  carbon  loop  and  from  P 
thru  G,  O  and  P  to  the  carbon  loop.  But 
remembering  that  the  direction  of  the  cur- 


rent is  reversed  or  apparently  so,  then 
when  the  galvanometer  is  connected  to  the 
negative  terminal  N,  the  difficulty  is  to 
understand  how  the  current  there  produced 
could  possibly  overcome  the  current  from 
the  source  supplying  the  lamp.  It  was  also 
noticed  that  the  deflection  of  the  galvano- 
meter needle  was  quite  feeble  when  con- 
nected to  the  negative  terminal. 

In  Fig.  2,  we  have  another  lamp  whose 
parts  are  the  same  as  in  Fig.  1  only  two 
platinum  strips,  PD,  placed  parallel  to  each 
other  are  incorporated.  Prof.  Edwin  J. 
Houston  at  that  time  said  that  if  a  current 
is  produced  when  terminals,  O,  are  con- 
nected to  the  galvanometer,  then  the 
phenomena  is  still  more  difficult  of  ex- 
planation, but  he  believed  that  one  pole  of 
the  electrical  source  or  power  is  always 
connected  with  the  galvanometer,  the  other 
being  connected  with  either  or  both  of  the 
platinum  plates ;  such  being  the  case  the 
phenomena  would  simply  be  a  modifica- 
tion of  the  action  in  bulb  shown  in  Fig.  1. 

He  also  believed  that  in  some  way  the 
molecular  bombardments  against  the  plat- 
inum plate  produced  an  electrical  current; 
such  being  true,  then  if  terminal  N,  is  con- 
nected with  the  galvanometer,  the  current 
would  flow  thru  the  galvanometer  in  an 
opposite  direction  to  the  current  from  the 
electrical  source,  rendering  the  previous 
idea  untenable,  owing  to  the  fact  that  the 
phenomena  could  not  be  described  as  a 
Crookes'  effect. 

But  if  we  suppose  this  opposite  current 
out  of  the  way,  then  it  may  show  the  suf- 
ficiency of  the  Crookes'  effect  as  an  ex- 
planation of  the  phenomena.  This  was 
illustrated  by  further  experiments  per- 
formed by  Mr.  Edison,  which  threw  no 
little  light  on  the  matter.  Referring  to 
Fig.  3,  instead  of  placing  the  platinum 
pole,  P,  inside  the  carbon  loop,  it  was 
placed  at  the  end  of  a  long  tube  T,  this 
tube  forming  a  part  of  the  lamp  chamber. 
When  connections  were  made,  as  shown, 
with  the  platinum  plate  at  P,  so  as  to  place 
it  in  line  with  the  carbon,  and  therefore 
expose  the  filament  to  the  bombardment 
of  the  molecules  shot  out  from  the  charged 
platinum  disc,  the  needle  of  the  galvano- 
meter was  deflected,  even  tho  the  tube  T 
was  surrounded  by  a  freezing  mixture. 
However,  when  the  platinum  plate  was 
placed  at  P\  in  the  branch  tube,  out  of 
{Continued  on  page  578) 


Modified  "Valve"  Tried  by  Edison,  In  Which 
the  Auxiliary  Electrode  "P"  Was  Mounted 
at  the  End  of  an  Extended  Chamber  "T." 
Distinct  Galvanometer  Deflections  Were 
Easily  Obtained  With  This  Device. 


December,  1917 


THE  ELECTRICAL  EXPERIMENTER 


537 


The  How  and  Why  of  Radio  Apparatus 


No.  5 — Radio  Transmitting  Inductances. 

From  time  to  time  we  will  describe  one 
particular  instrument  used  in  either  the  ra- 
dio transmitting  or  receiving  set,  explain- 
ing just  how  it  works,  and  why.  We  have 
received  so  many  requests  from  new  read- 
ers asking  for  such  explanations,  that  we 
have  decided  to  publish  this  matter  in  serial 
form.  In  the  course  of  several  issues  all 
of  the  principal  transmitting  and  receiving 
apparatus  will  have  been  covered.  The 
subject  for  the  second  paper  is  RADIO 
TRANSMITTING  INDUCTANCES. 

RADIO  transmitting  inductances  are 
of   several  types.    The  principal 
characteristic    of    this  particular 
piece  of  apparatus  is  that  it  in- 
variably has  an  "air"  core,  in  con- 
tradistinction to  the  ordinary  alternating 
current  inductance,  which  is  most  always 
provided  with  a  laminated  iron  core. 

The  difference  between  these  two  forms 
of  inductance  as  just  described  is  due  to 
the  fact  that  the  frequency  is  so  high  in 
radio  oscillatory  circuits  that  iron  cannot 
be  efficiently  used  for  several  reasons. 
There  may  come  a  day  when  we  shall  have 
radio  inductances  with  iron  cores,  but  up 
to  the  present  time  it  has  not  been  found 
practicable  to  provide  them,  even  tho  there 
is  a  very  large  loss  due  to  the  electro- 
magnetic induction  which  has  to  take  place 
thru  air  which,  as  is  well-known,  is  a  very 
poor  conductor  of  magnetism.  Iron  at  radio 
frequencies  and  in  such  circuits  as  these 
tends  to  lag  behind  the  rapidly  changing 
current,  and  gives  a  very  low  power  factor, 
besides  producing  a  high  loss  due  to 
hysteresis. 

We  will  take  up  in  this  paper  several 
types  of  tuning  inductances  used  in  radio 
transmitting  circuits,  and  which  have  been 
adopted  in  actual  practise.  Fig.  1  shows 
what  is  known  as  the  "pan-cake"  or  spiral 
inductance.  This  is  a  very  effective  form, 
particularly  when  wound  of  flat  copper  rib- 
bon. It  is  sometimes  built  of  heavy  round 
wire,  but  the  flat  ribbon  of  course  gives 
the  most  efficient  results.  Spring  clips  are 
provided  with  practically  all  inductance  coils 
of  these  types,  so  that  any  part  thereof  may 
be  included  in  the  circuits  to  which  they 
are  connected. 

The  inductance  illustrated  in  Fig.  2,  com- 
prises what  is  known  as  an  auto-trans- 
former. In  this  case  a  single  winding  serves 
as  both  primary  and  secondary.  The  pri- 
mary circuit  being  connected  across  at  P, 
and  the  secondary  circuit  connected  across 
the  clips  at  S  or  SI,  etc.  It  is  possible  to 
vary  the  coupling  between  the  primary  and 
secondary  circuits  to  some  extent  with  such 
a  transformer,  by  connecting  one  of  the 
circuits  to  the  position  SI  (i.e.,  widely 
separated),  for  instance,  as  related  to  the 
second  circuit  at  P. 

The  dotted  lines  running  axially  in  dia- 
grams here  shown  indicate  the  magnetic 
field  set  up  when  current  passes  thru 
the  coil,  and  the  action  of  the  auto-trans- 
former becomes  evident  from  Fig.  2,  as  it 
will  be  seen  that  all  of  the  turns  in  the 
coil  are  threaded  or  cut  by  magnetic  flux 
created  in  it.  Thus  it  is  possible  to  in- 
crease the  potential  of  a  circuit  with  a 
single  winding  as  shown.  When  potentials 
are  to  be  increased  by  auto-transformers, 
the  ratio  between  primary  and  secondary 
voltages  is  usually  not  greater  than  3  to 
1  or  8  to  1. 

Diagram  Fig.  3  shows  the  simplest  form 
of  loose-coupled  oscillation  transformer  for 
transmitting  circuits,  and  which  comprises 
a  helix  P,  into  which  a  smaller  coil  S, 
or  secondary,  may  slide.  The  spark  gap 
circuit  is  usually  connected  to  the  outer  coil 


or  across  the  clips  P,  while  the  aerial  and 
ground  connections  are  made  to  the  movable 
secondary  coil  S.  In  any  case,  the  number 
of  turns,  or  fraction  of  a  turn,  in  either 
circuit  are  adjusted,  with  a  hot-wire  am- 
meter connected  in  the  ground  lead,  until  a 
maximum  radiation  current  is  obtained.  Of 
course,  the  wave  length  must  be  checked  on 
a  wave  meter,  or  else  computed,  but  the 
wave  meter  method  is  always  preferable. 
The  action  of  this  two-coil  oscillation  tun- 
ing transformer  is  evident  from  the  illus- 
tration Fig.  3,  where  it  is  seen  that  the 
magnetic  flux  lines  from  coil  P,  cut  across 
the  turns  of  the  secondary  coil,  even  tho  the 


thus  variable  and  the  amount  of  inductance 
in  either  circuit  is  adjustable  as  in  other 
types  of  transformers ;  i.e,  by  changing  the 
numbers  of  active  turns  in  circuit.  The 
position  for  maximum  coupling  with  this 
oscillation  transformer  occurs  when  the  sec- 
ondary and  primary  coils  are  placed  in  the 
same  axial  relation ;  when  the  secondary  coil 
is  rotated  90  degrees,  or  in  a  position  at 
right  angles  with  respect  to  the  primary 
coil,  a  position  of  minimum  coupling  is  ob- 
tained. The  magnetic  flux  field  is  shown  by 
the  dotted  lines  as  in  the  other  diagrams. 

There  is  another  form  of  two-coil  oscilla- 
tion tranformer  which  has  been  used  quite 


Pancake  or  Spiral  Inductance 


Sec 
Movable 


Trolley  wheel 


Prim, 


~8- 


yar.  Coupling 
-9- 


All  of  the  Principal  Types  of  Radio  Transmitting  Inductances  Are  Illustrated  Above.  The 
Peculiar  Characteristics  of  Each  One  Are  Explained  in  the  Accompanying  Text. 


coils  are  often  quite  widely  separated. 

Maximum  coupling  is  obtained  when  the 
secondary  coil  is  all  the  way  within  the 
primary  coil,  and  vice  versa.  A  unique  type 
of  transmitting  inductance  having  two  coils, 
one  for  the  secondary  and  one  for  the  pri- 
mary, is  shown  at  Fig.  4. 

This  type  has  found  much  favor  in  com- 
mercial radio  circles,  and  works  very  effi- 
ciently when  it  is  properly  related  to,  and 
designed  for  use  with  a  certain  type  and 
size  transmitting  set.  The  primary  coil 
which  is  usually  the  larger  one  is  shown  at 
P,  while  S,  or  the  secondary  coil,  is  rota- 
tably  mounted  in  a  fixt  axial  position  above 
the  primary.    The  degree  of  coupling  is 


extensively  in  commercial  radio  work  as 
well  as  in  experimental  and  amateur  sta- 
tions, and  this  is  illustrated  at  Fig.  5. 

Here  the  secondary  as  well  as  the  pri- 
mary windings  are  fixt  and  mounted  upon  a 
stationary  frame.  Considerable  variation  in 
the  coupling  can  be  obtained  by  causing  the 
secondary  active  turns  to  be  at  the  upper 
end  of  the  fixt  secondary  winding,  while 
the  active  primary  turns  are  caused  to  be 
at  the  lower  end  of  the  fixt  primary  wind- 
ing, and  vice  versa. 

One  of  the  easiest  ways  of  making  a  two- 
coil  oscillation  transformer  is  based  upon 
this  principle,  and  necessitates  the  cutting 
(Continued  on  page  574) 


538 


THE  ELECTRICAL  EXPERIMENTER 


December,  1917 


Efficient  Dry  Battery  Service  for  Audions 

By  RALPH  BATCHER 


NOTWITHSTANDING  the  progress 
made  in  storage  battery  construction 
in  recent  years  still  the  uses  for  dry 
batteries  are  increasing  as  never  before. 


Fig. 

1 

'■rgy 

f\ 

h 

\  j 

i 

'3 

i 

i 

i 

% 

i 
i 

@ 


Load  /n  amperes 


Fig.  1.  Graphic  Curve  Showing  the  Energy 
That  Can  Be  Obtained  From  a  Dry  Cell  with 
Various  Discharge  Rates.  The  Maximum 
Ampere-Hours  Output  Was  Obtained  with  a 
Load  of  .35  Ampere,  as  Will  Be  Observed. 

Since  the  advent  of  the  "Radio  vacation" 
all  amateurs  who  are  really  experimenters 
have  been  planning  improvements  for  their 
stations  when  the  day  should  come  when 
the  "lid"  was  removed.  Those  who  have 
not  used  an  Audion  are  planning  a  way  to 
procure  this  important  piece  of  apparatus. 
But  with  an  Audion  a  storage  battery  is 
necessary,  they  are  told.  But  since  all 
amateurs  have  not  access  to  charging  facil- 
ities they  must  use  dry  batteries. 

The  question  now  remains  to  find  out  if 
dry  batteries  can  be  used  with  any  degree 
of  efficiency,  and  if  so  how  they  should  be 
connected. 

A  tubular  Audion  bulb  has  a  resistance 
[hot]  of  about  4.25  ohms.  This  value  is 
the  average  of  several  bulbs  burned  at  about 
normal  brilliancy.  Such  a  bulb  takes  from 
.9  to  1.1  amperes  (generally  nearer  the 
former  value).  From  Ohm's  Law  (voltage 
equals  amperes  multiplied  by  ohms  resist- 
ance) we  find  that  it  will  take  from  4  to  4.5 
volts  imprest  on  the  filament  to  furnish 
this  amount  of  current.  A  dry  cell  gives 
1.5  volts  so  at  least  three  cells  in  series  will 
be  required.  It  may  be  necessary  to  use 
a  rheostat  with  a  lower  resistance  and  finer 
variations  than  the  one  generally  used,  if 
but  three  cells  are  used.  With  this  arrange- 
ment but  very  little  current  would  be  lost 
in  the  rheostat  resistance  itself. 

Referring  to  Fig.  1  a  curve  is  given  show- 
ing the  energy  that  can  be  obtained  from 
a  dry  cell  with  various  discharge  rates.  The 
curves  are  plotted  from  data  furnished  by 
the  National  Carbon  Co.,  obtained  with 
ordinary  batteries.  In  the  computation  of 
the  life  of  a  cell,  the  time  was  taken  until 
the  voltage  dropt  to  .8  volt. 

It  will  be  seen  that  for  intermittent  use  of 
1  hour  daily,  that  the  greatest  number  of 
ampere-hours  are  obtained  when  .35  am- 
pere is  taken  from  a  cell.  Thus  three  cells 
must  be  used  in  parallel  if  1  ampere  is  to 
be  used  to  give  efficient  dry  cell  service. 
The  battery  must  contain  nine  cells  con- 
nected in  series-parallel  to  give  the  4.5 
velts  and  1  ampere.    The  combination  will 


give  a  little  over  325  watt-hours  of  energy. 
It  will  be  necessary  in  time  to  either  add 
another  cell  to  each  series  set,  or  reconnect 
them  so  that  four  cells  are  in  series  to  main- 
tain sufficient  voltage  to  operate  the  bulb. 

There  is  another  idea  that  can  be  followed 
up  when  it  is  desired  to  furnish  the  great- 
est amount  of  energy  to  an  external  circuit 
with  the  minimum  consumption  of  current, 
from  the  dry  cells. 

Ohm's  Law  states 
E 

1.  1= — ,  where  I  equals  the  current  in 
R 

the  circuit,  E  the  voltage,  and  R  the  total 

resistance. 

The  electrical  expression  for  energy  is 
P  =  RF 

Therefore,  since  I2  =  E2    P  =  RI2  =  E2R 

R2  R2 

R  is  equal  to  the  total  resistance  of  the 
circuit,  which  in  the  case  of  a  circuit  using 
dry  batteries,  is  equal  to  the  sum  of  the  ex- 
ternal resistance  (load)  and  the  internal 
resistance  of  the  cell  or  cells.  (It  should 
be  remembered  that  the  internal  resistance 
of  cells  in  series  adds  up,  while  the  resist- 
ance of  cells  in  multiple  follows  the  re- 
ciprocal law)  which  we  will  call  R  and  r 
respectively,  as  in  Fig.  2. 

E2  R 

Then  P  =  

(R+r)2 

Now  what  value  of  R  can  be  found  so 
that  the  useful  energy  in  the  circuit  is  at  a 
maximum  with  the  smallest  amount  of  cur- 
rent, this  is :  RI2  is  greatest  for  the  small- 
est value  of  I.    This  value  can  be  found 


m 

E 

i 

Fig  Z 

© 

Fig.  2.  To  Obtain  the  Greatest  Value  of 
Energy  in  a  Circuit  the  "External  Resist- 
ance" Must  Be  Equal  to  the  "Internal  Re- 
sistance" of  the  Battery.     That  Is  R  =  r. 

by  a  simple  application  of  differential 
calculus. 

Differentiating  Eq.  3, 
dP     —  2E*R+E>    (R+r)     — 2E*R+  E?R+  E2r 


dR 


(R+r)3 


E2  (r — R) 


(R+r)s 
=  O 


(R+r)' 

Solving  the  above  equation  for  the  real 
roots  gives  for  the  maximum  value 
r— R  =  0    or  R  =  r 

The  same  thing  can  be  shown  in  a  rough 
way  by  substituting  values  for  R  and  find- 
ing the  value  RI2  in  each  case. 

Therefore  to  obtain  the  greatest  value 
of  energy  in  a  circuit  the  "external  re- 
sistance" must  be  equal  to  the  "internal 
resistance"  of  the  cells. 


The  simple  peasant  soldiers,  many  of 
whom  come  from  remote  villages  where 
wireless  has  never  been  heard  of,  are  great- 
ly fascinated  by  the  station,  and  like  to 
stand  around  when  they  can  get  a  chance 
and  watch  the  flashing  of  the  spark  and 
listen  to  its  song.  "It  sounds  like  butter 
in  a  frying  pan,"  they  say.  They  have 
coined  a  nickname  for  the  men  in  the  wire- 
less crew,  which,  as  near  as  possible  in 
English,  is  "sparkers"  or  "the  spark  men." 


RUSSIAN  SOLDIERS  AMAZED  AT 
WIRELESS. 

An  interesting  description  is  given  by  a 
Russian  officer  of  one  of  the  numerous  little 
mobile  field  wireless  outfits  operating  near 
the  front.  The  whole  wireless  station  can 
be  unloaded  from  its  auto  truck,  rigged  up, 
and  be  ready  for  work  in  twenty  minutes. 
The  seventy-foot  masts  are  hollow  and  made 
in  sections,  which  are  screwed  together 
when  taken  off  the  truck. 


HOW  TO  OPERATE  AUDION  ON 
110  VOLTS  D.  C. 
By  Norman  A.  Woodcock. 

(De  Forest  Radio  Telephone  and  Tele- 
graph Co.) 
In  a  recent  article  in  the  Electrical 
Experimenter,  by  R.  F.  Yates,  the  question 
was  asked  as  to  why  the  use  of  a  high 
potential  battery  could  not  be  dispensed 
with  in  the  plate  circuit  of  an  Audion. 
Whilst  at  the  present  stage  of  development, 
a  high  potential  is  absolutely  necessary  be- 
tween the  plate  and  filament,  there  is  no 
longer  any  reason  why  batteries  should  be 
used  for  this  purpose. 

Thanks  to  a  recent  invention  due  to  Dr. 
Lee  de  Forest,  a  means  has  been  developed 
whereby  the  ordinary  110  volt,  D.  C.  supply 
can  be  utilized  instead  of  the  expensive  and 
cumbersome  flashlight  batteries  generally 
employed. 

The  circuit  shown  in  the  accompanying 
diagram  is  simple,  and  could  readily  be 
made  up  by  any  amateur  experimenter  pos- 
sessing a  little  ingenuity.  To  avoid  mistakes, 
the  entire  Audion  hook-up  is  shown.  This 
is  standard,  with  the  exception  that  the  high 
voltage  battery  in  the  plate  circuit  is  re- 
placed by  the  arrangement  now  to  be  de- 
scribed. 

The  ordinary  110  volt  D.  C.  mains  are 
connected  thru  a  pair  of  choke  coils  LiLj, 
to  the  terminals  of  a  condenser  Ci.  These 
choke  coils  may  be  composed  of  fine  in- 
sulated wire  wound  upon  iron  cores,  whilst 
the  condenser  may  be  of  1  or  2  m.f. 
capacity. 

R  represents  a  high  resistance  potentio- 
meter having  a  sliding  contact  as  indicated. 
The  resistance  should  range  from  about 
5000  to  25,000  ohms.  A  grafite  rod  will 
serve  the  purpose  admirably. 

The  remaining  condenser  C2  may  be  of 
1  m.f.  capacity,,  whilst  the  circuit  may  be 
grounded  as  shown  at  E  or  not,  as  found 
advisable  by  experiment.  Suitable  con- 
densers may  be  purchased  from  any  elec- 
trical supply  house,  as  they  are  in  common 
use  in  telephone  practise.  When  the  circuit 
is  properly  adjusted,  there  should  be  prac- 
tically no  noise  heard  in  the  telephones.  If 
this  is  not  the  case  at  first,  a  few  trial  ad- 


The  Proper  Connection  of  an  Audion  Detec- 
tor to  a  Direct  Current  Lighting  Circuit,  to 
Eliminate   the   "B"    Battery.     The  Latest 
Audion  Sets  Operate  In  This  Way. 

justments  will  usually  give  the  desired  re- 
sult. . 

It  should  be  hardly  necessary  to  add  that 
the  above  arrangement  will  not  work  on 
Alternating  Current. 


December,  1917 


THE  ELECTRICAL  EXPERIMENTER 


C^r^QCIJCZJaa — 1CZ3 


The  Uncrowning  of  the  Gimcrack  King 


DID  you  ever  have  a  large,  fat  for- 
tune come  and  stare  you  in  the 
face,  hold  out  its  hand  in  the  most 
enticing  way,  and  then  suddenly 
turn  its  back  on  you  and  beat  it  ? 
I  did.  It  came  about  thru  my  advertising 
novelty,  the  "Sailing  Boat." 

In  my  early  days,  the  only  advertising 
novelty  was  to  advertise  at  all.  If  you  were 
going  to  all  the  trouble  of  running  a  store 
to  sell  thread  and  buttons  and  hoop-skirts, 
the  public  surely  ought  to  reciprocate  by 
giving  you  their  trade.  They  had  to,  any- 
way, if  yours  was  the  only  place  in  town. 
You  didn't  need  to  tell  them  where  to  go ; 
and  to  tease  them  into  buying  when  they 
didn't  really  need  to  would  have  been 
wicked. 

Advertising  was  resorted  to  only  as  a 
simple  home  remedy  for  an  attack  of  com- 
petition. Suppose  some  mercantile  pirate, 
without  regard  for  God  or  man,  opened  up 
a  store  next  door  to  yours,  with  a  line  of 
buttons  that  the  women — the  crazy  things ! 
— liked  better  than  the  ones  the  drummer 
stung  you  on  three  years  ago,  and  com- 
menced swiping  your  trade.  Well,  when 
you'd  become  sufficiently  scared,  and  your 
wife  was  going  strong  on  how  she'd  always 
told  you  so  but  you  wouldn't  listen  to  her 
and  what  was  going  to  become  of  the  happy 
home  now,  you  sought  the  village  editor  and 
paid  him  seventy-five  cents  for  an  adver- 
tisement in  his  paper,  something  like  this  : 


H.  GREEN 
Dry  Goods. 
14  Main  Street 


No  pictures  of  women  in  the  corset-stage 
of  plumage — mercy  sakes  ! — or  offers  to  sell 
goods  for  less  than  they  cost  you — what 
were  you  in  business  for,  anyway  ?  No,  mere- 
ly a  dignified  reminder  that  the  public  was — 
no  doubt  inadvertently — straying  from  the 
only  legitimate  joint  in  which  to  garb  itself 
in   proper   garbage.     What   an   expense ! 


Detail  of  Crepe  Paper  "Water"  and  Method 
of  Covering  Slot  So  That  Post  Supporting 
Boat  Would  Not  Leave  Slot  Open. 

Seventy-five  cents  just  for  that,  when  you 
knew  the  editor  used  the  same  type  over 
again  for  something  else,  so  it  didn't  cost 


By  THOMAS  REED 

him  anything.  However,  it  had  to  be  done ; 
and  now  you  hoped  to  goodness  your 
trouble  with  that  competitor  was  at  an  end. 
Such  was  adyertising  before  it  began  to  be 


he  had  bestowed  a  moment, 
window  of  a  restaurant,  and 
miniature  of  that  restaurant 
perfect  as  could  be,  with 


It  was  in  the 
consisted  of  i 
itself,  just  a; 
a  file  of  lear 


Here's  the  Boss  "Gim-crack" — It  Almost  Coined  Money.    The  Breeze  From  the  Electric  Far, 
Caused  the  Sail-boat  to  Swing  Over  Realistically  As  It  Rounded  the  Curves.    The  Boat 
Was  Propelled  on  a  Miniature  Electric  Railway  Car. 


spelled  with  a  large,  bold  face  capital  "A." 

I  remember  well  when  the  capital  "A" 
first  came  within  my  ken.  Uncle  George 
had  been  to  New  York,  and  one  evening  he 
dropt  in  and  told  us  about  it.  Things  had 
got  to  an  awful  pass  there,  he  said.  Quan- 
tities of  stores  kept  the  very  same  articles, 
and  the  only  way  to  get  any  trade  at  all, 
or  even  keep  what  you  had,  was  to  adver- 
tise. Some  people  did  it  every  little  while. 
It  was  a  terrible  expense,  and  ate  into  your 
profits  like  anything. 

Well,  he  told  of  the  various  things  they 
did  to  catch  people's  attention,  and  I  was 
dozing  off  because  it  was  kind  of  warm 
in  the  sitting-room,  when  I  sat  up  with  a 
start,  for  he  was  talking  about  certain 
motion-novelties,  animated  "figgers"  in  the 
windows,  that  folks  stopt  to  look  at.  Any 
silly  contraption  would  draw  a  crowd,  he 
said ;  tho  he  couldn't  see  the  use  of  it,  be- 
cause most  everybody  just  looked  and  past 
along,  and  never  even  went  into  the  store 
at  all.  Personally,  he  wouldn't  waste  his 
time  looking  at  such  "gimcracks." 

There  was  one  exception,  tho,  on  which 


people  going  in  one  door,  and  a  file  of  fa: 
ones  coming  out  another  door.    'As  much 
as  to  say  they'd  eaten  a  lot  inside  the  place 
— explained  Uncle  George  for  fear  we'e 
miss  the  point — "see  what  I  mean?" 

If  this  novelty  was  the  only  one  Uncle 
George  had  favored  with  his  attention,  ht 
sure  made  up  for  it  with  his  neglect  of 
the  others ;  for  he  watched  its  operation  sc 
long  that  he  digested  his  last  meal  and  go: 
hungry  again  ;  and  this  restaurant  being  si 
near  him,  the  impulse  struck  him  to  be  I 
wild-eyed  sport  and  go  in  there  and  dint 
The  funny  thing  about  it  was,  he  founc 
the  dinner  first-rate,  and  cheaper  than  a: 
his  hotel,  so  he  took  all  the  rest  of  his  meal- 
there  while  he  stayed  in  town.  He  strongh 
recommended  the  place  to  Father  the  nex* 
time  he  should  go  to  New  York,  and  gave 
him  a  card  that  he'd  asked  the  proprietor 
for  on  purpose,  so  Father  could  find  it. 
"But  gosh,"  said  Uncle  George,  "you'd  never 
know  the  place  was  any  good  to  look  at  it — 
no  pies  or  cake  in  the  window,  nothing  at 
all  but  that  fool  toy — perfectly  useless,  and 
it  must  have  cost  a  lot,  too  "  According 


540 


THE  ELECTRICAL  EXPERIMENTER 


December,  1917 


to  him,  those  New  Yorkers  didn't  know 
any  better  than  to  throw  their  money  away. 

They  say  it  takes  the  new  generation  to 
get  the  fresh  viewpoint;  and  I  got  it,  tho, 


Side  View  of  Sail-boat  Mounted  on  Minia- 
ture Electric  Railway  Car.    The  Car  Motor 
Obtains    "Juice"   from    the   Two  Insulated 
Rails,  the  Axles  Being  Insulated  Also. 


of  course,  I  didn't  mention  it  aloud  because 
in  those  days  there  was  no  great  demand 
for  younger  generations'  fresh  viewpoints, 
or  freshness  of  any  kind.  In  spite  of  Uncle 
George's  disdain,  it  struck  me  that  if  a 
gimcrack  was  persuasive  enough  to  wean  a 
man  like  him  from  the  table  of  the  trusty 
Broadway  Central,  sell  him  a  long  line  of 
"eats,"  and  send  him  home  a  booster,  such 
contrivances  must  have  the  merchandising 
world  absolutely  by  the  tail. 

Instantly  a  vast  prospect  opened  to  me, 
of  success  and  wealth  in  this  direction,  for 
gimcracks  were  decidedly  in  my  line.  The 
only  trouble  with  those  which  I  was  always 
making  and  imagining  was  that,  tho  un- 
doubtedly interesting,  they  were  not  of  the 
slightest  use.  But  here  was  a  way  to  turn 
the  interest  into  use ;  and  I  pictured  an  end- 
less series  of  brilliant  mechanical  devices 
emanating  from  my  brain  like  the  fat  people 
from  Uncle  George's  restaurant,  faring 
forth  to  earn  me  royalties  and  make  me 
famous  as  the  "Gimcrack  King."  There 
was  practically  nothing  to  it;  in  fact,  I 
wisht  the  thing  had  been  a  little  more  diffi- 
cult, because  some  historian  in  later  times, 
reading  of  my  meteoric  rise,  might  get  wise 
to  the  fact  that  it  had  been  nothing  but  play 
to  me,  and  so  belittle  my  achievement. 

The  next  day,  I  was  at  work  on  Gim- 
crack No.  1.  I  realized  I  should  have  to 
begin  in  rather  a  small  way,  strictly  on  my 
private  resources.  I  was  averse  to  bor- 
rowing money  from  Father  for  the  promo- 
tion of  new  enterprises,  and  he  shared  my 
aversion  ;  I  may  even  say  that  since  the 
clock  episode  his  share  was  the  larger.  So, 
out  of  the  many  ideas  already  in  stock,  I 
chose  the  "Sailing  Boat,"  as  the  least  ex- 
pensive. 

The  accompanying  illustrations  show  the 
principle.  The  boat,  of  the  lightest  possible 
construction,  was  mounted  on  a  small  truck, 
rolling  on  a  track,  and  driven  by  a  toy 
electric  motor  "geared  down"  to  produce 
the  slow  and  stately  motion  of  a  floating 
craft.  A  slender  steel  post  elevated  the 
boat  itself  above  a  wooden  flooring,  con- 
cealing the  tracks  and  motor-truck,  and 
covered  with  blue  crepe  paper  to  represent 
the  sea ;  the  paper  being  continued  over  the 
edges  of  the  narrow  crack  thru  which  the 
post  ran,  meeting  at  the  middle  and  parting 


and  reuniting  on  the  passage  of  the  post,  so 
that  the  surface  appeared  unbroken. 

The  boat,  balanced  lengthwise  on  pivots 
and  weighted  at  the  bottom,  heeled  over 
with  a  natural  slant  to  starboard  and  port 
as  she  "beat  to  windward"  against  the 
breeze  from  a  concealed  electric  fan. 
Rounding  the  weather  buoy,  she  would 
straighten  out  and  go  off  "down  the  wind" 
to  the  other  end  of  the  ocean  floor,  when 
she  would  luff  majestically  round  the  lee- 
ward buoy  and  recommence  her  tacking. 

Elaborating  the  idea,  certain  sections  of 
the  tracks  were  insulated  and  provided  with 
small  resistance-coils,  so  that  the  boat 
varied  in  speed,  as  tho  the  wind  lulled  and 
freshened.  I  thought  of  introducing  later 
a  second  boat,  which  should  follow  the  first, 
sometimes  appearing  almost  to  overtake  it, 
but  always  losing  headway  at  the  critical 
moment — a  bid  for  the  sympathy  of  the 
large  "also-ran"  element  of  the  populace ; 
but  a  single  boat  was  all  I  was  able  to 
finance  at  the  start. 

When  this  rinktum  was  in  operation,  the 
family  were  invited  to  a  private  view. 
Being  obliged  to  impersonate  the  electric 
fan  myself,  my  lung-power  gale  produced 
an  unusually  "wild  night  on  the  coast,"  the 
good  ship  Mary  Ann  careening  till  she 
almost  (theoretically)  capsized  while  mak- 
ing hardly  any  progress,  then  going  at  a 
rapid  pace  without  her  sails  filling  at  all. 
This  inconsistency  being  duly  explained,  the 
family  admired  the  invention  mildly,  but 
toward  its  wealth-producing  function  they 
were  cool.     Hadn't  I  heard  what  Uncle 


Phantom  View  of  Sail-boat  Showing  Dispo- 
sition of  Lead  Balance  Weights  Inside  Hull. 
These    Keep    the  Boat    on    a    Level  Keel 
Normally. 


George  said?  New  Yorkers  might  waste 
their  money  on  such  things,  tho  even  they 
must  learn  wisdom  pretty  soon ;  certainly 
no  New  Englander  would  think  of  mutilat- 
ing his  hard-earned  profits  in  that  way.  I'd 
find  out,  they  guest.  Thus  they  put  the 
gloom  on  me,  as  families  always  do. 

An  inventor  is  never  a  good  promoter ; 
and  I  was  so  far  from  an  exception  to  the 
rule  that  I  amounted  to  what  you  might 
call  a  retro-moter,  or  one  whose  scheme, 
instead  of  going  forward  to  profit,  goes 
backward  to  a  point  where  he's  lucky  if 
he  can  let  go  of  it  before  it  tows  him  into 
the  Bankruptcy  Court;  but  I  didn't  know 
that  then.  Regarding  the  demand  for  the 
boat  as  a  certainty,  I  gave  careful  con- 
sideration to  the  amount  of  royalty.  $50.00 
a  week  occurred  to  me  as  a  convenient 
round  number.  It  was  worth  that,  of 
course ;  but  it  would  probably  be  better 
along  the  first,  until  the  business  was  es- 
tablisht,  to  charge  much  less,  say  $25.00  or 
even  $10.00  tho  it  would  have  to  be  under- 
stood that  this  was  a  temporary  rate  for 
introductory  purposes  only. 

From  even  the  introductory  $10.00  rate,  I 
evolved  some  highly  satisfactory  figures. 
The  Sailing  Boat  had  cost  me,  all  told, 
$2.03,  so  that  practically  five  new  ones  could 


be  built  from  each  week's  profits.  At  the 
end  of  the  second  week,  therefore,  my 
income  would  be  $60.00;  at  the  end  of  the 
third  week,  $360.00;  fourth  week,  $2,220.00; 
fifth  week,  $13,32000 ;  and  sixth  week,  $79,- 
920.00.  I  stopt  there  because  the  supper- 
bell  rang.  It  seemed  like  a  lot  of  money. 
Perhaps,  to  be  perfectly  safe,  one  had  better 
call  it  an  even  $70,000.00;  there  might  be 
setbacks,  of  course.  Anyhow,  when  the 
weekly  receipts  reached  some  such  figure, 
it  would  be  safe  to  divert  part  of  the  profits 
from  development,  and  perhaps  purchase 
one  or  two  articles  of  luxury. 

Now  please  don't  interrupt  me  while  I 
tell  of  the  disastrous  beginning  (which  was 
also  the  end)  of  my  campaign  to  introduce 
the  Sailing  Boat,  because  I'm  much  older 
now  and  very,  very  much  wiser,  and  I 
anticipate  your  suggestion  that  instead  of 
tackling  the  most  successful  merchant  in 
town,  I  should  have  approached  the  strug- 
gling fellow  who  felt  the  need  of  something 
to  stimulate  trade.  Sure,  sure;  I  know. 
But  as  the  amounts  of  money  already  in- 
volved were  so  large,  I  felt  that  the  lessee's 
credit  was  the  first  consideration ;  so,  as 
intimated,  I  opened  negotiations  with 
Zebediah  Crowell,  whose  dry -goods  and 
notion  store  was  the  thriftiest  thing  within 
the  purlieus — Zebediah,  while  the  tightest 
wad  in  town,  being  apparently  best  equipt 
to  stand  the  strain  of  my  royalties. 

Altho  my  anticipations  of  profit  were 
somewhat  too  intoxicating  for  a  no-license 
town  such  as  mine,  I  needed  them  all  to 
offset  the  parental  scepticism ;  for  father 
said  that  no  money  ever  got  away  from 
Crowell's  grip  without  suffering  internal 
injuries  in  the  process.  So  my  state  of 
mind  might  be  described  as  firmness,  rather 
than  optimism,  as  I  entered  his  imposing 
store,  lugging  my  large  package  with  diffi- 
culty, blusht  when  asked  what  it  was  I 
wisht  to  purchase,  and  stammered  my  desire 
for  a  personal  interview  with  the  proprietor. 

I  had  nerved  myself  to  the  spectacle  of 
Zebediah  enthroned  in  a  spacious  and  lux- 
uriously-fitted private  office,  and  only  hoped 
it  would  contain  a  table  on  which  I  could 
make  my  demonstration  with  proper  effect. 
Mr.  Crowell  at  that  particular  moment, 
however,  was  said  to  be  in  the  basement; 
and  bumping  with  my  parcel  down  a  flight 
of  very  steep  and  dark  stairs,  I  came  upon 
the  great  man  engaged  in  one  of  the  intrica- 
cies of  trade. 

He  was  seated  in  the  dim  light  of  the  only 
window,  before  a  box  of  tangled  strings, 


End  View  of  Boat  and  Electric  Car.  The 
Motor  Drives  a  Counter-shaft  So  As  to  Re- 
duce the  Speed  of  the  Wheels. 


patiently  undoing  the  knots   and  snarls, 
sorting  the  strings  into  sizes,  and  tying  each 
(Continued  on  page  578.) 


December,  1917 


THE  ELECTRICAL  EXPERIMENTER 


541 


REMOVING  RUST  ELECTRICALLY. 

What  we  call  rust  on  iron  or  steel  is 
merely  a  coating  formed  by  the  combining 
of  the  iron  with  oxygen,  which  coating  is 
apt  to  form  in  the  presence  of  moisture. 
Since  the  obnoxious  color  of  the  rust  is 
due  to  the  oxygen  in  the  moisture,  any 
method  which  will  decompose  the  rust  so 
as  to  set  the  oxygen  free  will  leave  the 
bright  metal.  Now  it  is  well  known  that 
when  two  terminals  of  an  electrical  circuit 
are  dipt  in  water,  hydrogen  is  set  free  at 
one  of  the  terminals  and  oxygen  at  the 
other;  therefore,  what  we  need  to  do  is  to 
have  the  rusty  metal  form  the  cathode  at 
which  the  oxygen  is  given  off.  Pure  water 
is  a  poor  conductor  of  electricity,  hence  one- 
tenth  of  its  volume  of  ordinary  sulfuric 
acid  should  be  slowly  poured  into  the  water. 
Adding  the  acid  heats  the  water  and  this 
should  be  allowed  to  cool  before  inserting 
the  terminals,  which  would  consist  of  the 
rusty  pieces  as  cathodes  and  a  piece  of 
lead  or  lead  pipe  as  the  anode. 

Contributed  by  PETER  J.  M.  CLUTE. 


A  CONVENIENT  LOCATION  FOR 
AUTO  HORN  BUTTONS. 

Usually  when  one  is  driving  a  car,  the 
horn  has  to  be  sounded  just  when  both 
hands  are  needed  most  on  the  steering 
wheel,  or  for  some  other  purpose.  The 
electric  horn  buttons  are  located  quite  de- 
sirably on  a  large  number  of  the  new  cars ; 
however,  there  are  many  older  cars,  on 
which  it  is  desirable  to  install  an  electric 
horn,  as  many  people  enjoy  the  charm  of 
a  second  horn  in  addition  to  the  one  al- 
ready on  their  car.  In  either  case  the  lo- 
cation of  the  horn  button  is  almost  sure 
to  raise  .a  question.  A  most  convenient 
location  for  this  horn  button  can  be  made 
by  boring  a  half-inch  hole  in  the  rim  of 
the  steering  wheel,  as  in  Fig.  2.  In  this 
hole  put  a  small  push  button,  which  can 
be  obtained  at  (any  Willys-Overland  ser- 
vice station)  most  electrical  supply  stores. 
If  the  push  button  is  placed  a  little  toward 
the  inside  of  the  rim,  the  danger  of  touch- 
ing it  accidentally,  will  be  eliminated.  The 
wires  may  be  run  on  the  under  side  of  a 
spoke,  and  down  the  steering  post  in  the 
usual  way. 

As  the  horn  is  used  mostly  at  crossings 
and  before  rounding  curves,  the  button  will 
always  be  under  the  hand  which  is  the  least 
needed  for  steering  at  the  time,  if  placed 
at  the  lowest  point,  as  shown.  For  ex- 
ample, if  you  wish  to  make  a  turn  at  your 
right,  you  will  naturally  pull  toward  you 
with  your  right  hand ;  this  will  bring  the 
push  button  a  little  toward  the  left,  bring- 


The  Best  Place  for  the  Auto  Horn  Button  Is 
on  the  Steering  Wheel. 


ing  it  under  the  free  hand,  which  will  not 
have  to  be  removed  from  the  wheel  to 
reach  the  horn  button. 
Contributed  by 

H.  CORCELL  STUART. 


Due  to  the  advent  of  the  war,  we  are 
particularly  desirous  of  obtaining  snappy 
manuscripts  describing  original  and  prac- 
tical "Electrical  Experiments." 


The  MysteriousWoice 

A  Clever  Electrical  Illusion 
By  C.  A.  OLDROYD 


THE  effect  of  this  electrical  illusion  is 
as  follows :    The  performer  sits  at  a 
piano  and  plays  a  tune  which  has  been 
selected  by  one  in  the  audience.    After  he 
has  been  playing  for  a  few  moments  a  voice 


He  sings  into  the  microphone,  M,  and  puts 
the  lever  Y,  of  the  three-way  switch  N, 
into  the  position  Zt.  The  current  will  then 
pass  over  the  wire  V  into  the  loud-talker, 
W,  which  is  concealed  behind  let  us  say 


Room  A 


Room  & 


The  Amateur  Electrician  Will  Find  This  "Stunt"  Very  Effective.    By  Means  of  Sensitive 
Microphones  and  Loud-speaking  Telephones  the  Audience  Is  Induced  to  Believe  That  a  Real 
"Mind-reading"  Seance  Is  Taking  Place. 


is  suddenly  heard  which  sings  the  very  same 
tune.  The  voice  seems  to  come  from  behind 
the  stage,  but  after  a  few  bars  of  the  song 
the  voice  seems  to  come  from  a  far  corner 
of  the  room — perhaps  from  the  ceiling. 

While  the  audience  is  looking  in  that  di- 
rection, trying  to  discover  the  mysterious 
singer,  the  voice  suddenly  changes  and 
seems  to  come  now  from  a  third  place — the 
midst  of  the  audience — only  to  change 
back  again  to  one  of  the  former  points  in 
a  jiffy.  The  explanation  of  this  "stunt"  is 
given  below. 

Referring  to  the  diagram,  we  have  two 
rooms,  A  and  B,  about  twenty  yards  apart. 
The  performer  C,  and  piano  D  and  the  au- 
dience are  in  room,  B.  A  sensitive  micro- 
phone, E,  is  concealed  behind  some  cur- 
tain or  other  decorations  and  two  wires, 
F  and  G,  lead  from  E  to  a  telephone  I  in 
the  room  A.  This  telephone  is  provided 
with  a  head  band,  worn  by  an  assistant,  K. 
A  battery  H,  consisting  of  a  few  dry  cells 
is  connected  in  series  with  the  microphone 
and  telephone.  The  assistant  K,  sits  in 
front  of  a  table  L,  to  which  is  secured  a 
sensitive  microphone,  M,  in  a  convenient 
position.  One  binding  post  of  this  micro- 
phone is  connected  to  a  wire  O,  a  battery 
P,  and  finally,  by  means  of  the  wire  Q,  to 
loud-speaking  telephone  receivers,  R,  T  and 
W. 

The  other  binding  post  of  the  micro- 
phone M,  is  connected  by  a  wire  X  and  a 
three-way  switch,  N.  This  switch  consists 
of  a  wooden  base  upon  which  are  mounted 
a  lever,  Y,  and  three  contacts  Zi,  '  Za 
and  Z3.  Zi  is  connected  by  a  wire  V  to  the 
loud-speaking  'phone  W ;  Z2  by  U  to  T  and 
Z3  by  wire  S  to  R. 

It  is  now  clear  that  the  assistant  can,  at 
will,  by  means  of  the  three-way  switch,  N, 
connect  any  of  the  loud-speaking  'phones 
T,  R,  or  W,  to  the  microphone,  M. 

The  operation  of  the  illustration  is  car- 
ried out  as  follows : 

The  performer  C,  in  room  B,  is  asked  by 
a  member  of  the  audience  to  play  a  cer- 
tain tune.  The  assistant  K,  in  room  A, 
hears  the  music  of  this  tune  in  his  'phone  I. 


a  jardiniere.  After  a  few  moments  the 
assistant  changes  the  position  of  the  switch, 
N,  to  say  Z2,  and  the  voice  will  then  be 
heard  coming  from  the  'phone  T,  which 
may  be  concealed  in  the  midst  of  the  audi- 
ience  or  behind  a  picture. 

If  the  lever  Y  is  changed  to  position  Z3 
the  voice  will  be  heard  in  the  loud-talker 
R,  and  so  on.  The  placing  of  the  'phones 
must  be  left  to  the  experimenter,  but  very 
good  places  are :  in  flower-pots,  under  ta- 
bles and  behind  pictures.  In  every  case, 
care  must  be  taken  that  the  opening  of  the 
'phone  horn  is  not  obstructed.  With  a  little 
care  this  can  be  easily  provided  for,  as  by 
having  a  number  of  artificial  rose  bushes  or 
other  flowers  arranged  in  two  rows  and  the 
lane  between  them  leading  in  a  direction 
down  which  the  audience  cannot  see. 


A  NOBLE  USE  FOR  AMATEUR 
RADIO  TRANSMITTERS. 

I  have  thought  of  a  plan  to  utilize  every 
amateur  sending  set  in  the  country  and  help 
in  the  saving  of  life  and  the  success  of  the 
war.  Simply,  it  is  this  : — Let  every  amateur 
take  his  sending  set  and  fix  it  up  to  work 
at  the  ordinary  commercial  wave  length, 
and  put  the  outfit,  which  should  be  worked 
off  dry  cells,  in  a  5  gallon  coal  oil  tin, 
securely  fastened.  The  whole  is  then  sold- 
ered up  absolutely  air-tight.  The  key 
should  be  on  the  outside  in  a  little  compart- 
ment, with  a  glass  cover,  also  air  tight. 
The  sending  terminal  may  also  be  in  this 
space.  The  aerial,  about  No.  20  copper 
wire  (a  single  strand)  is  attached  to  a  fold- 
ing box  kite,  the  wire  being  wound  on  a> 
reel  mounted  on  bearings  attached  to  the 
set,  which  is  crated  or  rather  protected 
with  wood  to  withstand  knocking  about. 
Now  one  of  these  sets  with  simple  instruc- 
tions and  a  copy  of  the  code  is  to  be  placed 
in  every  life  boat  on  the  merchant  ships 
leaving  American  ports.  This  would  avoid 
some  of  the  dreadful  stories  of  hardship, 
starvation  and  death,  which  reach  our  ears 
every  now  and  then. 

Contributed  by  WILLIAM  H.  GRAY 
Lake  Buntzen,  B.  C,  Canada. 


542 


THE  ELECTRICAL  EXPERIMENTER 


December,  1917 


An  Electrically  Played  Mandolin 


WELL,  Bugs,  it's  time  to  think  about 
those  long  winter  evenings,  so 
clear  out  your  think-tank  and 
light  up  your  jimmy  pipe.  This 
is  a  real  job,  fellow  experimenters,  and  a 
task  that  will  keep  you  interested  right  up 


By  McCLURE  ALBRIGHT 

ing  the  note  of  "E-natural."  If  contact 
32  was  closed  instead,  then  the  fret  (finger 
position)  magnet  corresponding  to  "F-natur- 
al"  would  be  actuated,  (see  detail  of  this 
mechanism  in  Fig.  4)  ;  the  current  passing 
on  thru  pick  actuating  magnet  "E,"  this 


4  PfC/f  confrot  magnets 


'6  "string  * 
Pick  magnet^ 


44 Finger  Contact  ^ 


f  e  d'd  c"c  b  a"  a  g'g  f"f  e  f'f  e  d'd  c"c  b  a*a  6  a'a  g'g  f*f  e  d"d  e  d'd  c"  c  6  a'a  g*g 

■14  43  42  41 40  39 38  37 3S  3S M 333231 30  23  28  27  ZS  2£ 24 23 22 2/20  IS  18  17 /6  15  14  13 12  tt  10  987  654321 


Fig.  1. — General  Plan  of  Circuits,  Pick  Magnets,  Pick  Rotating  Motor  and  bwitch-board  Used  in  Electrically 
alayed  Mandolin.  The  Same  Idea  as  Here  Described  Is  Also  Applicable  to  a  Guitar  With  a  Little  Ingenuity.  The 

Details  Are  Quite  Simple. 


:o  the  time  you  are  ready  to  throw  in  the 
motor  switch  and  listen  to  the  automatical- 
ly played  mandolin.  The  ideas  here  out- 
lined are  also  applicable  to  a  guitar  with 
iome  modifications. 

All  of  the  details  are  not  given  as  most 
experimenters  like  to  have  the  pleasure  of 
working  out  the  general  arrangement  and 
style  of  the  outfit  themselves.  The  as- 
sembly scheme  involves  a  sufficiently  large 
base-board  upon  which  the  mandolin  will 
it,  together  with  various  fret  and  pick  con- 
trol magnets,  as  well  as  the  pick-rotating 
motor. 

Referring  to  Fig.  1,  we  have  a  general 
layout  of  the  fret  (finger)  and  pick  control 
electro-magnets,  also  the  circuit  connections 
to  pick  driving  motor  and  finger  control 
board.  A  perforated  paper  roll  is  drawn 
thru  the  latter,  each  perforation  permitting 
a  contact  finger  to  make  contact  with  the 
copper  plate  as  shown  in  detail  in  Figs.  3  &  1. 
This  part  of  the  work  presents  a  fine 
chance  to  learn  something  about  music,  if 
you  are  not  already  proficient  in  that  classic. 

The  wiring  can  be  easily  traced  out. 
When  an  open  string  is  to  be  played,  the 
current  passes  right  thru  to  the  desired 
pick-magnet  only ;  when  any  other  note  is 
to  be  played  the  current  passes  thru  the  fret 
(finger)  control  magnet  first  and  then  to  the 
pick  magnet.  All  four  strings  can  be  played 
simultaneously  if  desired.  As  an  example 
of  the  pick  and  fret  magnet  action,  con- 
sider that  contact  31  is  closed ;  this  causes 
the  pick  (constantly  rotated  by  the  motor) 
over  the  open  "E"  string  to  function,  giv- 


sounding  the  note  of  "F-natural,"  et  cetera. 
There  are  40  fret  control  magnets,  which 
may  be  old  bell  magnets. 

Fig.  2  shows  the  simple  manner  of  ar- 
ranging the  pick  rotating  motor  and  gears. 


The  four  pick  shafts  could  also  be  driven 
by  friction  wheels  and  would  make  less 
noise.  The  constantly  spinning  picks  are 
raised  away  from  or  lowered  into  contact 
with  the  strings  by  virtue  of  the  pivoted 
suspension  shaft  Y,  and  the  pick  control 
arms  X,  X,  X,  X,  at- 
tached to  four  electro- 
magnets as  indicated  in 
Fig.  3-A.  The  arms  X, 
are  normally  held 
above  the  strings  by 
spiral  springs  as  shown. 
By  means  of  the  stop 
screw  XI,  the  move- 
ment of  the  pick  arm 
X,  may  be  controlled 
so  as  to  get  the  best 
sound.  It  must  not 
strike  the  string  too 
heavily ;  neither  must 
it  sound  the  string  too 
lightly.  A  little  experi- 
ment will  soon  clear  Up 
this  point,  when  the 
whole  arrangement  is 
lined  up  for  final  ad- 
justment. The  pick 
control  magnet  may  be 
a  large  bell-magnet  coil 
or  telegraph  sounder 
magnet.  If  the  builder 
desires  to  make  his  own 
magnets  (four required) 
they  can  be  built  from 
a  wrought  iron  core  y2" 
in  diameter  by  2y2" 
long.  Fiber  spool  ends 
are  fastened  on  the 
core,  these  having  a 
diameter  of  iy&".  The 
bobbin  is  wound  full  of 
No.  26  single  cotton 
covered  magnet  wire,  if 
6  volt  battery  current 
is  to  be  used. 

The  small  motor 
which  drives  the  pick 
shafts  can  be  a  6  volt  battery  type,  giving 
say  1/40  horse-power.  The  "Little  Hustler" 
motor  is  too  small ;  those  selling  at  $3.00  to 
$4.00  are  about  the  right  size.  It  can  be 
either  shunt  or  series  wound.    One  main 


r  Perforated  paper  no// 

s  tnru  nere. 
-Copper  back  ptate . 


\  'IB  dear/n^g 


Bevel  gears  . 


Gear-Xm 


Figs.  2  and  2-A. — A  Detailed  View  of  the  Motor  Drive  for  the  Rotary  "Picks,"  With  Reduction 
Gears  and  Also  the  Rods  for  Raising  and  Lowering  the  "Picks"  Themselves. 


December,  1917 


THE  ELECTRICAL  EXPERIMENTER 


543 


switch  controls  the  motor  and  magnet  cir- 
cuits as  becomes  evident. 

The  wiring  to  the  fret  magnets,  etc., 
may  consist  of  ordinary  bell  or  fixture  wire. 
It  should  be  fanned  out  neatly  at  the  term- 
inals and  shellacked  or  tied  in  place,  the 
same  as  telephone  wires  on  switchboards. 

It  will  pay  to  cultivate  some  musical 
friends  if  you  are  not  thoroly  familiar  with 
notes,  and  chords.  With  a  little  ingenuity 
a  paper  roll  perforator  can  be  devised,  hav- 
ing a  keyboard  corresponding  to  the  con- 
tact switch-board  layout  in  Fig.  1. 


ratchet  drum  inside  the  body  of  the  car. 
This  drum  has  a  small  handle  projecting 
on  the  outside  of  the  cab,  and  by  means  of 
the  ratchet  wheel,  the  drum  remains  in 
whatever  position  it  is  turned  to. 


A  MYSTERIOUS  PICTURE. 

If  you  are  invited  to  a  party  and  want  to 
amuse  the  good  people,  the  following  trick 
will  keep  them  guessing  for  weeks: 

Procure  a  portrait  of  a  member  of  the 


ELECTRIC  ARCS  UNDER 
PRESSURE. 

Recent  improvements  in  searchlights 
have  taken  the  form  of  various  methods  of 
cooling  the  electrode  with  a  view  to  ob- 
taining greater  local  concentration  of  the 
light,  either  by  a  spray  of  alcohol  or,  as 
in  the  Sperry  searchlight,  by  a  blast  of  air. 

Another  line  of  development  being  in- 
vestigated in  Germany  has  been  the  use  of 
arcs  under  high  atmospheric  pressure. 
Lummer  was  reported  to  have  obtained 
promising  results  shortly  after  the  out- 
break of  war,  and  it  was  thought  possible 
that  a  considerable  improvement  in  the  ef- 
ficiency of  arc  lamps  and  projectors  might 
be  secured  in  this  way.  According  to  some 
experiments  described  by  Mathies-;n  in  the 
Elektrotechnische  Zeitschrift,  this  anticipa- 
tion is  not  being  realized.  Pressures  vary- 
ing from  a  vacuum  up  to  5  atmospheres 
compression  were  utilized,  both  with  in- 
clined and  vertical  carbons.  In  the  former 
case  a  marked  gain  in  efficiency  was  se- 
cured, but  the  arc  was  found  to  become 
very  unstable  for  pressures  exceeding  one 
atmosphere.  On  the  other  hand,  with  ver- 
tical carbons  more  stable  con- 
ditions are  realized,  but  the 
gain  in  efficiency  seems  to  be 
very  moderate. 


//o/e  for  pick  c  rod 


Perforations 

o'jjinr 

14  fingers  ///re 

/n/s  rega/red 

Figs.  3  and  4. — Showing  Details  of  "Fret"  Stop  and  Pick  Raising  and  Lowering  Magnets  as 
Well  as  End  View  of  Switch-board  and  Sample  of  Perforated  Paper  Roll  Which  Opens  and 

Closes  the  Circuits. 


The  two-conductor  cable  connecting  the 
car  with  the  central  pedestal  receives  its 
current  thru  two  metal  brushes  making 


A  TRACKLESS  ELECTRIC 
CAR. 

The  accompanying  illustra- 
tion shows  a  very  interesting 
trackless  electro-mechanical  car 
or  engine,  which  is  operated  by 
current  supplied  thru  the  ordi- 
nary lamp  socket  and  a  step- 
down  transformer.  The  feed 
wires  drop  down  from  above 
to  the  special  central  pedestal. 
Thus,  there  are  no  wires  to  in- 
terfere with  the  electrically 
driven  vehicle  spinning  round 
and  round  in  a  circle  on  the  floor. 

The  toy  may  be  set  to  rotate  in  any  size 
circle,  the  length  of  the  flexible  electric 
cord  being  adjustable  by  means  of  a  small 


Narrow  pari  of  neck  is  7/8  'tn/ck 
Mde       .    .     .     .  ike'  - 
fre/s  are  f/3z  'n/g/t  and  '^32' /nick 


party  in  question,  but  without  his  knowl- 
edge, of  course.  Have  an  enlargement  made 
of  the  picture,  which  after  being  fixt  must 
be  thoroly  washed.  Place  it 
in  a  solution  of  mercuric 
chloride  (be  careful:  poi- 
son!) until  the  image  has 
absolutely  disappeared.  Wash 
well  again  and  let  dry. 

Now  you  are  ready  for  the 
party.  Fasten  your  enlarge- 
ment on  an  easel  such  as 
painters  use.  From  the  dis- 
tance it  will  appear  as  a  blank 
sheet  of  paper.  Only  very 
close  examination  would  dis- 
close the  fact  that  the  sheet 
is  prepared. 


Detail  of  Mandolin  Neck  Used  by  Author  in  Building  Electrically  Played 

Instrument. 

contact  with  two  oppositely  charged 
rings  on  the  pedestal.  A  patent  on  this 
ingenious  toy  has  been  awarded  to  Walter 
E.  Thayer  of  Brooklyn,  N.  Y. 


Tell  your  audience  that  you 
have  suddenly  developed  an 
artistic  talent  and  that  you 
are  going  _  to  give  some  proof  of  your 
maestria,  right  now. 

Produce  your  painters  brush  and  a  con- 
tainer apparently  containing  black  ink.  This 
liquid  is  prepared  beforehand  in  the  fol- 
lowing manner :  Fill  a  glass  full  of  water 
(about  12  to  15  ounces,  to  which  add  two 
drams  of  ammonia,  take  a  little  India  ink 
and  stir  it  in  this  mixture  so  as  to  make 
the  liquid  look  black.  Be  careful  not  to  add 
too  much  India  ink,  so  that  when  brushed 
on  the  paper,  it  will  not  leave  any  marks. 

Have  the  members  of  the  party  now  sit 
or  stand — as  required  by  your  portrait — 
some  distance  from  the  easel,  and  begin  to 
proceed  to  bring  out  the  picture,  by  applying 
the  ammonia  mixture  with  your  brush. 
Much  to  the  astonishment  of  the  audience 
a  fine  picture  appears  in  a  few  seconds. 
Contributed  by 

LEONARD  VINCHINO. 


A  Clever  Electric  Toy  In  the  Form  of  a  Miniature  Engine,  Which  Runs  In  a  Circle  and 
Without  Tracks.   Current  Is  Supplied  to  the  Motor  from  a  Central  Pedestal. 


Due  to  the  advent  of  the  war,  we  are 
particularly  desirous  of  obtaining  manu- 
scripts describing  original  and  practical 
"Electrical  Experiments."  We  shall  con- 
tinue to  publish  Radio  articles,  but  what 
we  need  is  snappy  "Electrical"  articles. 
Be  on  guard  for  the  enemy — Repetition! 


544 


THE  ELECTRICAL  EXPERIMENTER 


December,  1917 


An  Automatic  Storage  Battery  Charger 

By  LEWIS  SGRIVEN 


AUTOMATIC  storage  battery  charging 
switchboards  are  becoming  more  the 
general  practise  wherever  this  type  of 
battery  is  used.    Its  use  is  significant,  and 
as  its  name  implies  automatically  keeps  the 
battery  in  its  proper  condition  at  all  times, 


P  1.  (The  charging  source  is  presumed  to 
be  110  volts  direct  current.) 

Referring  to  the  electrical  wiring  the  op- 
eration is  as  follows : — Suppose  the  bat- 
tery is  fully  charged ;  relay  L  armature  will 
be  up.    All  contacts  on  the  cog-wheel  will 


Battery 


Ser/ice 


Storage  Battery  Charging  Is  Always  a  Long  Job,  Besides  Being  a  Very  Critical 
One.    To  Charge  Them  with  the  Minimum  of  Trouble  and  Care,  Use  Should  Be 
Made  of  an  Automatic  Switch-Board  Such  as  That  Illustrated. 


something  which  the  ordinary  person  often 
forgets.  The  general  description  which  fol- 
lows will  clearly  show  how  such  a  board 
operates. 

Referring  to  the  diagram:  A  is  a  balance 
bar  15  to  20  inches  long,  pivoted  at  B, 
having  a  contact  point  at  A  2  to  meet  A  1 ; 
and  C  a  counter  weight.  D  is  an  oil  cup 
in  which  a  plunger  (shown  sectionally)  is 
allowed  to  move  freely  from  side  to  side; 
but  not  loose  and  is  suspended  from  a  light 
rod  from  the  bar  A.  By  having  the  rod  A, 
a  trifle  heavy  to  counter-balance  C,  it  is 
allowed  to  fall  slowly  by  the  buoyancy 
of  the  oil.  Part  E  is  solidly  fastened  to 
A,  and  serves  to  push  F,  so  as  to  release 
armature  (which  it  holds)  when  A  is  at 
its  lowest  point. 

G  is  a  relay  having  an  armature  with 
a  contact  which  catches  on  the  hook  of 
F,  when  A  is  up  its  full  height.  H  is  the 
magnet  used  to  lift  A. 

I  is  a  cog  wheel  having  a  rim  about  54- 
inch  wide  with  a  notch  in  it  as  shown  by 
dotted  line,  and  on  this  rim  rests  a  rod 
which  is  used  to  close  contacts.  J  is  a 
ratchet  pawl  pivoted  on  A,  which  turns  this 
cog  wheel  on  the  upward  motion,  and  K 
a  stop-ratchet,  so  wheel  cannot  turn  back- 
wards. 

L  is  a  potential  relay,  which  when  the 
voltage  falls,  allows  its  armature  to  drop, 
making  contact  with  the  point  under  it, 
which  must  be  adjustable.  The  point  above, 
altho  not  a  contact  point,  must  also  be 
adjustable.  By  having  the  armature  a  cer- 
tain distance  from  the  magnet  core  it  is 
allowed  to  drop  at  the  battery's  run-down 
voltage.  While  down  it  should  be  such  a 
distance  from  the  core  that  it  will  pick  up 
at  the  normal  voltage. 

M  is  a  charging  relay  having  brass  plugs 
N  and  O,  to  close  contact  springs  directly 
above  each. 

P  is  a  trouble  relay  having  a  contact  on 
its  armature  which  breaks  when  it  is  up, 
but  closes  other  contacts  to  light  a  lamp. 
The  armature  when  up,  is  retained  by  catch 


be  open,  relay  M  armature  down,  and  relay 
P  armature  down.  Since  A  will  have  fallen 
to  its  lowest  point,  relay  G  armature  will 
be  down,  making  contact. 

The  voltage  falls.  Immediately  the  relay 
L  falls,  closing  two  of  the  contacts  on  the 
cog-wheel,  energizing  coils  H,  lifting  A  so 
that  A  1  and  A  2  meet.  This  energizes  the 
coils  of  relay  G,  breaking  the  energy  in  re- 
lay H,  and  A  having  nothing  to  hold  it  up, 
begins  to  slowly  drop.  Meanwhile  ratchet 
pawl  J  has  turned  the  cog-wheel  enough  to 
close  all  contacts  on  it,  which  energizes  re- 
lay M,  sending  the  charging  current  thru 
the  battery;  the  intervals  of  time  between 
the  contacts  at  A  1  and  A  2  should  be  about 
one  or  two  minutes.  The  arm  A  will  now 
work  up  and  down  until  the  contacts  are 
again  opened  by  the  notch  in  the  cog-wheel. 
As  the  diagram  here  shows  it,  the  bar  A  is 
in  the  act  of  falling  but  has  not  yet  re- 
leased the  armature  of  relay  G. 

Relay  M  should  not  take  more  than 
ampere. 

Relay  P  should  not  take  more  than  1/25 
ampere. 

Relay   G  should   not  take  more  than  lA 
ampere. 

Relay  L  should  not  take  more  than  1/25 
ampere. 

Magnet  H  should  not  take  more  than  ^ 
ampere. 

The  trouble  relay  P  is  a  necessity.  Its 
armature  is  heavily  adjusted  so  that  it  takes, 
say  about  fifty  volts  to  lift  it.  Should  the 
battery  become  disconnected  while  charg- 
ing, the  high  voltage  will  immediately  lift 
the  armature,  being  held  by  catch  P  1, 
opening  cog-wheel  contacts  which  cuts  off 
relay  M,  and  lights  lamp  to  indicate  trouble. 
This  prevents  high  voltage  passing  over  the 
battery  wires.  Attention  is  also  called  to 
the  fact  that  the  negative  charging  source 
is  grounded.  Should  the  negative  service 
wire  become  grounded,  no  harm  will  be 
done.  Should  positive  service  wire  become 
grounded  (causing  a  short-circuit)  its  fuse 
will  blow.   Otherwise,  if  the  positive  charg- 


ing source  had  been  grounded  and  negative 
service  become  grounded,  the  battery  would 
discharge  thru  the  resistance. 

This  board  can  be  made  to  operate  on  any 
size  battery,  by  winding  the  coils  to  suit, 
altho  24  volt  batteries  seem  to  be  standard 
for  low-tension  work. 

The  resistance  could  also  be  a  bank  of 
lamps,  its  resistance  depending  upon  the 
charging  rate  of  the  battery.  (Eight  hours 
is  the  standard  rate  for  charging  lead  plate 
cells.) 

These  boards  are  used  in  some  of  the 
finest  buildings  and  while  only  one  type  is 
here  described,  any  number  of  batteries  can 
be  controlled  by  one  board  by  a  few  minor 
changes  and  extra  relays  to  care  for  the 
different  sets. 


HOW  TO   PHOTOGRAPH  LIGHT- 
NING. 

Don't  use  films,  but  use  low  speed  thickly 
coated  plates.  The  camera  should  be  firmly 
posted  on  a  window  sill,  and  focused  for 
infinity.  Of  course  the  shutter  should  be 
open.  Watch  the  storm  and  as  soon  as 
lightning  occurs  close  the  shutter  again. 

It  requires  quite  a  lot  of  experiments  to 
get  a  good  forked  flash.  Some  time  a  good 
picture  may  be  spoiled  by  sheet  lightning 
occurring  just  a  few  seconds  after  the  ex- 
posure. 

Quick  handling  is  necessary  for  good  re- 
sults. Develop  plates  fully,  using  a  con- 
trast-giving developer. 

Contributed  by  JOS.  MINDER. 


COIL  WINDING  MACHINE  FOR 
AMATEURS. 

The  accompanying  illustration  shows  a 
view  of  an  efficient  coil  winding  machine. 
It  should  be  made  to  any  convenient  size. 
The  treadle  (A)  is  connected  to  a  large 
pulley  wheel  (B)  by  a  rod  (C)  as  shown. 
This  runs  a  smaller  wheel  (D)  which  is 
fastened  to  an  axle  by  a  set-screw.  A  set 
of  pins  (E)  are  also  fastened  to  the  inside 
end  of  the  axle.  At  the  other  side  a  pivot 
is  made  of  a  long  wood  screw.  The  up- 
right which  holds  the  pivot  is  made  movable 
and  may  be  put  in  different  holes  (G)  ac- 
cording to  the  coil  to  be  wound.  (H)  is  a 
brace  for_  the  movable  upright.  With  the 
aid  of  this  machine  one  may  wind  a  coil 
very  rapidly. 

Contributed  by  THEODORE  LAUER. 


A  Practical  Winding  Lathe  for  the  Amateur 
Electrician.    The  Rear  Pedestal  Is  Movable 
and  Is  Secured  in  Various  Positions  by  Means 
of  Dowels. 


December,  1917 


THE  ELECTRICAL  EXPERIMENTER 


545 


How  to  Build  A  One-Watt  Motor 

By  W.  J.  HOWELL 


FROM  time  to  time  publications  contain 
pictures  of  small  electric  motors  and  a 
short  description  of  how  many  "fly- 
power"  the  motor  is  able  to  deliver.  Most  of 
the  articles  state  that  said  motor  is  very  small 
in  size  and  that  jewelers'  tools  were  used 
to  make  it,  but  all  these  failed  to  convince 
me  that  fine  tools  were  needed  and  if  the 


Photograph  of  Tiny  One-Watt  Electric 
Motor,  Details  for  Building  Which  Are 
Given  Herein. 


list  given  below  is  studied  it  will  be  seen 
that  the  tools  that  were  used  are  those 
that  every  experimenter  has  or  ought  to 
have  in  his  work-shop.  The  list  is  as  fol- 
lows ;  shears,  drills  and  drill  holder,  small 
vise,  three  cornered  file  with  one-eighth 
inch  sides  and  a  half  inch  flat  file,  small 
fret  saw  using  fine  saw  blades,  pair  of 
tweezers  and  a  needle  holder,  which  is  a 
small  bar  with  a  hole  in  the  end  for  hold- 
ing a  needle  which  can  be  used  for  prying 
in  small  spaces,  pair  of  pliers,  with  pointed 
tips  and  a  small  soldering  iron  made  from  a 
piece  of  brass,  half  inch  by  one  quarter 
round,  and  mounted  on  a  piece  of  iron 
wire  stuck  into  a  wooden  handle. 

The  motor  itself  is  not  the  smallest  thing 
in  captivity  but  is  just  about  small  enough 
to  be  easy  to  make  and  handle  and  there 
is  no  danger  in  showing  it  to  other  people 
and  fearing  that  they  will  lose  it  under 
their  finger  nail.  I  am  of  the  opinion  that 
it  is  possible  to  make  one  even  smaller 
just  thru  my  experience  in  overcoming 
construction  details  with  this  one,  but  that 
is  something  that  can  be  tried  by  those 
who  will  and  have  the  time  to  work  at 
the  task,  for  task  it  is — altho  patience  is 
half  the  battle  and  believe  me,  one  needs 
it  in  large  quantities  besides  a  fair  ability 
to  handle  tools. 

The  shaft  is  made  of  a  piece  of  iron  wire 
about  the  size  of  a  number  22  copper  wire 
and  is  one  and  one-eighth  inches  over  all. 
The  next  thing  to  build  is  the  commutator ; 
this  is  made  of  brass  tube  one-quarter  inch 
long,  altho  the  actual  bearing  surface  is 
about  two-thirds  of  this  length.  The  tube 
should  just  be  large  enough  to  pass  over 
the  shaft  and  still  leave  room  for  some 
insulating  material  such  as  one  layer  of 
Empire  cloth.  The  tube  I  used  is  a  trifle 
over  one-sixteenth  inch  in  diameter  with 
very  thin  walls.     Before  cutting  off  the 


piece  for  the  commutator,  saw  it  with  two 
cuts  into  four  parts  or  segments,  making 
the  cuts  about  one  quarter  inch  long.  Clean 
the  inside  surface  of  the  tube  and  free  it 
from  all  burrs  left  by  the  saw  and  force 
it  over  the  shaft,  not  forgetting  to  put 
on  the  Empire  cloth  to  insulate  it  from 
the  shaft.  Tie  the  four  free  ends  of  the 
tube  down  by  a  thread  wound  several  times 
around  it,  about  an  eighth  of  an  inch  from 
the  end,  and  bend  these  ends  up  so  that  the 
armature  wires  can  be  soldered  to  them. 
Then  saw  off  the  rest  of  the  tube  and  tie 
those  four  ends  down.  This  construction 
gives  a  commutator  that  is  round  and 
each  segment  is  insulated  from  the  shaft 
and  from  each  other. 

The  armature  is  made  of  five  iron  wash- 
ers, three-eighths  inch  diameter,  and  as 
the  holes  in  the  washers  are  too  large  for 
the  shaft  the  difference  can  be  taken  up 
by  putting  on  several  layers  of  Empire  cloth 
and  the  washers  forced  on  until  they 
are  about  an  eighth  of  an  inch  from  the 
four  bent  ends  of  the  commutator.  Divide 
the  end  washer  into  eight  parts  and  make 
a  saw  cut  at  each  mark  until  the  saw 
reaches  a  point  midway  between  the  out- 
side and  in-side  diameters  of  the  washers. 
This  is  done  to  all  five  at  the  same  time  by 
holding  in  a  vise.  When  finished,  file  away 
four  alternate  pieces  of  iron  and  this  will 
leave  four  poles,  around  which  the  arma- 
ture coils  (of  which  there  are  four)  will 
be  wound.  Be  careful  to  remove  all  rough 
places  and  then  put  on  a  shellac  coating 
over  the  washers  thick  enough  to  act  as 
an  insulator,  because  there  will  not  be  very 
much  room  for  any  paper  insulation  of 
any  kind.  Wind  each  coil  when  the  shellac 
is  dry,  with  36  silk  covered  copper  wire, 
taking  care  on  the  first  layers  not  to  cut 
thru  the  shellac.  When  finished,  the  four 
poles  will  have  four  coils  which  take  up 
most  of  the  room  in  the  slots  between 
them,  and  the  ends  of  the  coils  are  con- 
nected to  the  starting  ones  of  the  next  coil ; 
that  is,  the  beginning  of  one  coil  is  con- 
nected to  the  ending  of  the  adjacent  coil 
and  the  beginning  of  that  coil  to  the  ending 
of  the  next  coil,  and  so  on,  until  the  entire 
four  coils  are  connected  in  series.  It  is  of 
course  understood  that  all  the  coils  are 
wound  in  the  same  direction,  so  that  by 
following  the  above  system  of  connection, 
they  will  be  hooked  up  in  the  proper  man- 
ner. Now  turn  the  commutator  so  that  the 
bent  up  tips  come  midway  between  the 
iron  poles  and  solder  the  wires  to  the  tips. 
This  is  best  done  by  putting  a  little  flux 
on  the  tip  and  pass  the  two  wires  which 
are  twisted  together,  over  the  tip  and  hold 
the  surplus  wire  down  the  other  side  of 
the  armature  with  the  fore-finger,  heating 
the  small  soldering  iron  in  a  Bunsen 
flame  with  the  other  hand,  which  when  hot 
enough  and  properly  tinned  will  pick  up  a 
drop  of  solder  and  held  to  the  tip,  thereby 
securing  the  wire  to  it.  The  surplus  wire 
is  of  course  cut  off. 

It  is  best  while  winding  the  four  coils 
to  test  for  grounds  to  the  washers  and  then 
unwinding  and  rewinding  carefully  so  as 
not  to  cut  thru  the  shellac.  With  care  the 
armature  should  be  in  the  class  that  gives 
no  trouble.  Paper  could  be  put  on  for 
insulation  but  it  requires  a  lot  of  extra  time 
and  shellac  is  alright,  if  handled  properly. 

Next  in  line  comes  the  field-frame  work 
and  this  is  made  of  an  iron  pipe  three 
quarters  inch  diameter  and  one-half  inch 
long.  It  is  about  one  thirty-second  of  an 
inch  in  thickness.  At  one  point  drill  a 
hole  about  three-sixteenths  inch  in  diameter 
and  carry  the  hole  straight  thru  the  other 


side,  care  being  taken  that  it  divides  the 
pipe  into  equal  parts  or  halves.  These 
holes  are  then  filed  square  so  that  two 
pieces  of  iron  about  one-quarter  inch 
square  and  three-sixteenths  inch  in  length 
can  be  driven  in  the  holes.  Now  cut  a 
brass  strip  one-eighth  inch  wide  and  a  little 
longer  than  the  diameter  of  the  frame  and 
solder  it  parallel  to  the  pole  pieces,  across 
one  end  of  the  tube.  This  is  to  be  one 
bearing  and  a  little  solder  can  be  put  on 
the  pole-pieces,  to  make  sure  that  they  stay 
in  place,  but  before  the  brass  strip  is  put 
on  solder  the  pole-pieces  and  then  file  them 
concave  so  that  the  armature  has  a  little 
clearance  space  between  them  to  turn. 

Place  the  drill  holder  with  a  number  60 
drill  in  the  chuck,  in  the  vise  and  hold  the 
brass  strip  up  and  drill  thru  the  middle. 
This  gives  a  hole  of  just  about  the  right 
size  for  the  shaft.  Remove  drill  from 
chuck  and  put  your  three-sixteenths  inch 
drill  in  its  place.  Bend  a  piece  of  card- 
board so  that  a  square  form  is  made, 
slightly  larger  than  the  square  iron  pole- 
pieces  and  slip  this  over  the  drill,  with 
possibly  a  piece  of  friction  tape  over  th« 
drill  to  take  up  the  difference  and  force  over 
the  card-board  two  pieces  of  the  same  ma- 
terial with  square  holes  cut  in  them.  Space 
these  about  one-eighth  inch  apart  and  you 
have  a  winding  form  to  wind  the  field  coils, 
which  are  about  one-half  inch  diameter  and 
made  of  No.  36  single  silk-covered  copper 
wire.  When  wound  take  care  in  removing 
the  same  from  the  form  and  by  leaving  a 
little  wire  at  the  end  this  wire  can  be  past 
thru  the  hole  in  the  coil  a  few  times  thereby 
securing  the  turns  in  place.  Two  pole- 
pieces  of  course  means  two  coils,  but  before 
placing  them  on  the  iron  pole-pieces,  the 
inside  of  the  frame  should  be  insulated 
with  a  strip  of  Empire  cloth  with  two 


Holes  for  brushes 


Bearing 


Amwlune  coil 'conn 


Details   for    Building   a   One-Watt  Electric 
Motor. 

square  holes  cut  in  it  in  order  to  allow 
it  to  pass  over  the  poles.  The  poles  them- 
selves have  a  small  piece  of  paper  wound 
on  them  as  insulation,  held  in  place  with 
shellac. 

{Continued  on  page  573) 


546 


THE  ELECTRICAL  EXPERIMENTER 


December,  1917 


USING  COMPASS  AS  WIND-DIREC- 
TION INDICATOR. 

The  underlying  principle  involved  in  the 
following  apparatus  is  that  a  compass 
needle  is  deflected  when  brought  near  a 
current-carrying  conductor.     To  make  it 


The  Electrical  Experimenter  Will  Find  This 
"Compass   Type"    Wind- Direction  Indicator 
Both  Useful  and  Instructive. 

more  clear  to  those  unfamiliar  with  the 
laws  relating  thereto,  we  shall  take  a  spe- 
cific case  as  an  example :  When  a  com- 
pass is  placed  over  a  wire  in  which  the 
current  is  flowing  South,  the  pole  of  the 
compass  will  be  deflected  toward  the  West ; 
the  amount  of  deflection  varying  accord- 
ing to  the  current  strength.  The  greatest 
possible  deflection  is  due  West,  or  at  right 
angles  to  the  North-South  wire.  So  if  we 
provide  sufficient  current,  the  needle  will 
point  directly  West.  If  the  current  flow 
were  to  be  changed  from  Northward  to 
Southward,  the  needle  would  point  East. 
Thus,  it  can  be  seen  that,  by  arranging 
connections  with  an  outside  weather  vane, 
which  creates  a  separate  circuit  for  each 
of  the  eight  principal  geographical  direc- 
tions, and  applying  the  principles  as  stated 
above,  we  may  use  the  compass  for  indi- 
cating the  direction  of  the  wind. 

The  construction  of  the  special  weather 
vane  and  its  operation  are  shown  quite 
clearly  in  the  drawings.  The  arrow,  made 
from  a  shingle  or  other  comparatively  thin 
wood,  is  mounted  at  its  balancing  point 
upon  a  %"  diameter  round  brass  rod.  This 
rod  or  pivot  turns  freely  in  the  brass  bear- 


Compcss  to  be  placed  over  crossing  of  mres  af'C  @ 


Circuits  Used  for  Electric  Wind-Direction 
Indicator   Built  from  a   Magnetic  Compass. 

ings  of  equal  inside  diameter  and  is  sup- 
ported by  the  collar  (soldered  to  it)  which 
rests  upon  the  lower  bearing.  From 
brass  sheeting  are  cut  the  segments,  with 


which  the  spring  brush  makes  contact. 
These  should  be  screwed  to  upper  sur- 
face of  the  bottom  of  the  box  at  proper 
distances  from  each  other,  and  around  the 
bearing  as  a  center.  One-half  inch  wood 
serves  for  the  box,  which  should  be  var- 
nished and  the  cracks  of  which  should  be 
filled  with  paraffin  to  keep  out  rain,  which 
would  soon  short-circuit  and  corrode  the 
segments.  Connections  are  made  to  each 
of  the  segments  and  the  lower  bearing. 

Current-carrying  wires  which  cause  the 
deflection  of  the  compass  needle  are  placed 
in  grooves  cut  in  a  small  wooden  block; 
two  wires  in  each  groove.  These  grooves 
may  be  cut  in  a  mitre-box  most  easily. 
The  wires  should  be  about  No.  18-20  B. 
&  S.  gage.  If  smaller,  heating  will  result. 
The  grooves  are  filled  with  wax  or  paraffin, 
which  is  then  smoothed  to  level  of  block 
with  sandpaper.  During  the  operation  the 
compass  is  placed  directly  over  the  cross 
of  the  wires  shown  at  "C"  in  diagram. 

Much  care  will  have  to  be  used  in  wir- 
ing the  square  block  with  the  weather 
vane.  However,  if  the  drawings  are  fol- 
lowed closely,  no  trouble  should  occur. 
The  rheostat  is  unnecessary,  but  with  it 
the  current  is  better  regulated.  The  num- 
ber of  batteries  will  vary  since  compasses 
in  each  case  will  differ,  as  also  will  the 
distance  from  vane  to  inside  block.  Note 
that  the  battery  is  connected  with  the  bear- 
ing from  positive  pole. 

Contributed  by     J.  L.  TAYLOR,  JR. 

(Ed.  Note:  While  this  is  a  very  good 
experiment  theoretically,  the  drain  on  the 
battery  would  prove  excessive  for  con- 
tinuous readings,  unless  gravity  cells  were 
used.  However,  for  periodical  readings 
the  scheme  is  practical  for  use  with  dry  or 
storage  cells,  utilising  a  switch  to  close  the 
battery  circuit  when  making  the  readings.) 


A  MYSTIC  SHOW  WINDOW 
ATTRACTION. 

A  novel  device  to  attract  the  attention  of 
passers-by  to  your  display  of  goods  is  pre- 
sented in  the  "inexhaustible  drinking  glass," 
which  seemingly  is  suspended  in  mid-air 
without  any  visible  means  of  support,  emit- 
ting large  quantities  of  water,  apparently 
coming  from  nowhere. 

The  illusion  is  set  up  as  follows :  Pro- 
cure a  tin-wash-basin  and  cut  a  quarter- 
inch  hole  in  the  center  of  bottom  for  the 
supply  tube  and  a  hole  near  the  edge  for  a 
54"  drain  pipe.  Drill  corresponding  holes 
in  floor  of  show,  window.  The  drain  pipe 
can  be  made  of  tin,  soldered  in  place  and 
extending  up  into  the  basin  to  within  about 
from  the  top.  The  lower  end  leads 
thru  the .  floor  of  window,  where  it  con- 
nects with  a  rubber  hose  which  carries  off 
the  waste  water. 

For  the  supply  you  will  need  a  glass  tube 
with  an  internal  diameter  of  from  %"  to 
3/16"  and  long  enough  to  extend  from  a 
few  inches  beneath  the  show  window  up 
into  the  basin  to  the  same  height  as  the 
pipe.  When  the  tube  is  in  place,  apply  a 
liberal  amount  of  soft  putty  on  the  under 
side  of  the  basin  around  the  tube. 

Place  the  basin  in  position  in  window, 
permitting  the  drain  and  supply  tubes  to 
extend  thru  their  respective  holes  in  the 
flooring.  Adjust  the  glass  tube  in  a  per- 
fectly vertical  position  and  press  down  tight- 
ly, squeezing  the  putty  in  place  to  prevent 
leaks. 

As  city  water  pressure  varies  greatly, 
due  to  other  consumers  turning  their  fau- 
cets on  and  off  when  drawing  water,  the 
glass  will  not  always  remain  at  the  same 
height,  rising  and  descending  with  a  jerky 
motion.  To  overcome  this  take  a  gallon 
can  of  any  kind  (an  old  varnish  can  will 
do),  connect  it  to  the  city  supply  pipe  and 
solder  a  small  tube  in  the  side,  to  which 


connect  the  glass  tube  with  a  small  rubber 
hose.    The  illustration  will  explain  this. 
Invert  a  light  weight,  thin  shell,  drinking 


The  Mystic  Electric  Tumbler  That  Floats  on 
a  Stream  of  Water.  Details  for  Building 
This  Interesting  Amusement  and  Show- 
Window  Attraction  Are  Given  in  the  Accom- 
panying Article. 


glass  over  the  glass  tube  in  the  basin,  and 
turn  on  the  water  slowly  at  first.  The 
glass  will  rise  in  the  air,  resting  on  the 
stream  of  water.  Its  height  can  be  varied 
with  the  stop  cock.  The  water  falling  from 
the  glass  obscures  the  supply  stream,  and  on 
striking  the  water  in  the  basin  it  causes  a 
wavy  surface,  thereby  hiding  the  glass  tube, 
its  effect  making  the  spectators  wonder  what 
is  holding  the  glass  up.  and  where  the 
water  is  coming  from.  A  coil  of  wire  slipt 
over  the  glass,  with  the  two  wire  ends 
sticking  out  as  illustrated,  makes  the  device 
look  "electrical."  This  serves  merely  to 
mystify  the  onlookers  still  more. 

Contributed  by  GEO.  NIEDERHOFF. 


Details  of  Basin  and  Water  Nozzle  Used  In 
Making  the  Mystic  Tumbler. 


WRITE  ARTICLES ! ! ! 

Now  is  the  time  to  write  up  that  favorite 
"stunt."  Make  it  brief — a  hundred  words 
or  so  will  tell  the  story.  Send  a  clear 
sketch,  or  better,  a  photograph  of  the  rink- 
tum.    Address  the  Editor. 


December,  1917 


THE  ELECTRICAL  EXPERIMENTER 


547 


This  department  will  award  the  following;  monthly  prizes:    First  Prize,  $3.00;  Second  Prize,  $2.00;  Third  Prize,  $1.00. 

The  purpose  of  this  department  is  to  stimulate  experimenters  towards  accomplishing  new  things  with  old  apparatus  or  old  material, 
and  for  the  most  useful,  practical  and  original  Idea  submitted  to  the  Editors  of  this  department,  a  monthly  series  of  prizes  will  be  awarded. 
For  the  best  idea  submitted  a.  prize  of  $3.00  is  awarded;  for  the  second  best  idea  a  $2.00  prize,  and  for  the  third  best  prize  of  $1.00.  The  article 
need  not  be  very  elaborate,  and  rough  sketches  are  sufficient.  We  will  make  the  mechanical  drawings.  Use  only  one  side  of  sheet.  Make 
sketches  on  separate  sheets. 


FIRST  PRIZE,  $3.00 


SECOND  PRIZE,  $2.00 


THIRD  PRIZE,  $1.00 


AN  ELECTRIC  PHONOGRAPH 
REPRODUCER. 

First  a  small  box  about  7"xl0"  is  pro- 
cured, then  a  round  disc  6"  in  diameter 
is  cut  out  (W).  A  dowel  is  fitted 
into  center  of  the  disc;  on  the  same  dowel 
a  spool  is  fitted,  a  short  piece  of  the  dowel 
being  left  protruding  thru  the  disc  to  put 
the  record  on.  Next  another  dowel  is  fit- 
ted with  a  spool  and  crank,  these  two 
dowels  and  all  attached  are  placed  as  shown 
in  diagram.  A  transmitter  is  made  from 
a  round  wooden  box  about  2"  in  diameter, 
a  round  carbon  (C)  is  fastened  to  the  bot- 
tom, a  carbon  of  the  same  size  is  fastened 
to  a  thin  tin  diafram  and  on  the  same  bolt 
a  long  binding  post  (B)  is  fastened,  around 
the  two  carbons  a  piece  of  paper  is  wound; 
in  between  the  carbons  are  carbon  granules 
(G).  A  connection  is  taken  from  the  dia- 
fram, and  the  bottom  carbon.  This  trans- 
mitter is  pivoted  on  an  arm  as  shown. 
The  needle  (N)  runs  in  the  groove  of  the 


A  Home-made  Electrical  Phonograph  With 
H.™d-d^?  Attachment  of  Simple  ConstVuc- 
tlon.     This   idea   Is  An   Excellent  One  for 
Experimentation. 

record  (R).  A  rubber  band  (H)  is  placed 
in  position  as  shown,  then  when  the  crank 
is  turned  the  wooden  disc  with  the  record 
turns  around  and  the  needle  runs  on  the 
record.  The  wires  from  the  transmitter 
are  connected  to  a  telephone  receiver  (K) 
and  battery  of  two  to  three  dry  cells 
Contributed  by  HERMAN  SLOBIN. 

Ey£I,RICAL    RECORDING  AND 
REPRODUCING  ATTACHMENT 
FOR  PHONOGRAPHS. 

A  simple  and  particularly  efficient  design 
tor  an  auxiliary  electric  recording  and  re- 
producing mechanism  for  attachment  to 
phonographs  is  shown  in  the  accompanying 
illustration,  and  this  idea  has  been  patented 
by  Newman  H.  Holland.  The  usual  re- 
cording and  reproducing  stylii  are  carried 
on  a  reversible  platen  or  head,  so  that  one  or 


TELEPHONE  RINGING  ATTACH- 
MENT. 

I  herewith  submit  a  novel  idea  to  the 
"HOW  TO  MAKE  IT"  department.  With 
this  telephone  bell  attachment,  a  second 


Spr/ng 


To  Ring  An  Extension  Bell  From  Any  Tele- 
phone Ringer,  Simply  Attach  An  Insulated 
Contact  Spring  to  the  Frame  as  Shown. 

bell  can  be  made  to  ring  in  any  part  of 
the  house.  A  small  piece  of  spring  brass 
is  bent  so  that  it  will  hit  the  armature 
of  the  telephone  bell  when  it  comes  up. 
With  a  few  insulating  washers,  it  can 
be  attached  to  the  frame  very  easily,  as 
there  is  a  bolt  that  extends  thru  the  upper 
part  of  the  frame.  The  nut  is  removed, 
and  the  spring  slipt  on.  The  door  bell  has 
a  wire  connected  from  the  contact  point 
to  the  spring,  so  that  its  interrupter  will 
not  work.  Two  batteries  are  sufficient  to 
run  it.  It  will  ring  every  time  the  'phone 
does. 

Contributed  by     EARL  MEISSNER. 

the  other  will  be  brought  into  contact  with 
the  phonograph  record  in  the  usual  manner. 
Instead  of  connecting  a  horn  to  the 
acoustic  chamber  above  the  stylii  and  dia- 
fram, this  chamber  is  foreshortened  and 
splits  up  into  two  distinct  or  branch  cham- 
bers, in  one  of  which  there  is  placed  a 
micro-phone  member  and  in  the  other  a 
telephone  receiver. 


Memo/  fee 


externa/  frvnsm. 


CARBON     GRAIN  TRANSMITTER 
MADE  FROM  RECEIVER  SHELL. 

A  simple  yet  efficient  microphone  may  be 
constructed  from  the  "junk"  found  around 
any  experimenter's  workshop. 

Referring  to  the  drawing:  (1)  and  (la) 
are  disks  sawed  from  an  old  round  battery 
carbon.  A  3/16"  hole  is  drilled  in  the  cen- 
ter of  each.  (2),  (2a)  and  (2b)  are  bat- 
tery binding  posts.  Binding  post  (2)  is 
inserted  thru  a  3/16"  hole  in  the  back  of 
the  receiver  shell  (3)  and  connected  to  the 
diafram  (4)  by  means  of  a  small  coiled 
wire  (5).  Carbon  disk  (1)  is  secured  to 
the  diafram  (4)  by  means  of  battery  bind- 
ing post  preferably  a  No.  6-32  rod  (2b). 
(6)  is  a  paper  tube  fitted  over  carbon  disk 
(la)  and  glued  or  shellacked  so  as  to  hold 
it  firmly.  Carbon  disks  (1)  must  be 
smoothed  on  its  edge  so  as  to  allow  it  to 
vibrate,  as  the  voice  waves  impinge  against 
the  diafram.  (7)  are  carbon  grains 
(scraped  from  an  ordinary  piece  of  car- 
bon) placed  in  the  paper  tube  (6)  between 
carbon  disks  (1)  and  (la).  (8)  is  the 
receiver  cap.  Best  results  are  obtained  by 
using  polished   carbon  grains   which  can 


An      Interesting      Combination  Electrical 
Recorder     and     Reproducer    for     Use  on 
Phonographs. 


The  Experimenter  Will  Find  This  Improvised 
Carbon  Microphone  Very  Serviceable,  Espe- 
cially If  Polished  Carbon  Grains  Are  Used 
In  It. 

be  purchased  from  any  electrical  supply 
house. 

Contributed  by     GEO.  H.  GORDON. 


The  microphone  member  on  the  phono- 
graph is  connected  with  a  common  battery 
as  indicated,  and  also  with  a  switch  attached 
to  the  traveling  phonograph  carriage,  so 
that  when  the  phonograph  is  talking  the 
speech  is  picked  up  by  the  attached  micro- 
phone and  sent  out  over  a  line  of  any 
desired  length  to  the  telephone  receiver.  In 
a  similar  manner  the  phonograph  can  be 
utilized  for  recording  speech  from  a  dis- 
tance, by  means  of  the  external  microphone, 
which  is  connected  thru  the  common  bat- 
tery to  the  telephone  receiver  mounted  in 
the  second  branch  of  the  acoustic  chamber 
on  the  phonograph  carriage.  This  idea  is 
often  very  useful  in  experimental  and 
laboratory  work. 


548 


THE  ELECTRICAL  EXPERIMENTER 


December,  1917 


HOME  MADE  GAS  LAMP  FOR  THE 
DESK. 

Many  experimenters  have  undoubtedly 
wanted  a  desk  lamp,  but  have  never  looked 
around  the  workshop  for  odd  pieces  of  ap- 
paratus with  which  to  make  one. 


A   Quickly    Made    Desk    Lamp  Constructed 
from  a  Ring  Stand,  a  Bunsen  Burner,  Goose 
Neck,  Mantle  and  Globe. 

The  photo  given  here  illustrates  a  method 
of  making  a  desk  lamp  from  the  following 
pieces : 

1  ring  stand ;  1  Bunsen  burner,  with  the 
part  removed  as  shown  in  photo,  1  regular 
goose-neck  fixture,  with  mantle  and  globe ; 
1  burrette  or  test  tube  clamp. 

Assemble  the  apparatus  as  shown  in  the 
photo  and  you  have  a  very  satisfactory 
study  table  or  desk  lamp  at  insignificant 
cost. 

Contributed  by 

ALBERT  W.  WILSDON. 


VOLT-AMMETER  SWITCHING 
SCHEME. 

Probably  many  of  the  readers  of  this 
journal  have  desired  to  use  a  Volt-ammeter 
for  measuring  both  the  voltage  and  amper- 
age without  changing  the  wiring,  but  have 
been  required  to  use  two  instruments,  as 
this  problem  requires  usually  several 
switches  and  complicated  wiring. 

I  have  had  this  trouble,  but  have  worked 
out  a  system  of  wiring  which  requires  only 
one  switch.  The  diagram  is  self-explana- 
tory, and  it  will  only  be  necessary  to  state 
that  C  is  the  common,  A  the  amperage  and 
V  the  voltage  post  of  the  meter.  Post  1 
is  connected  to  both  the  source  and  ap- 


Volt-  Ammeter 


'To  source 
of 'current 


To  apporatas-^y 


© 


By  Simply  Throwing  the  Switch  Shown  to 
Either  Right  or  Left,  "Amperes"  or  "Volts" 
May  Be  Read  On  the  Combination  Volt-Am- 
meter. 


paratus ;  either  2  or  3  may  be  connected 
to  the  source,  the  other  to  the  apparatus. 
Contributed  by  JOHN  D.  FORNEY. 


ELECTRIC  BELL  FOR  A  BICYCLE. 

The  drawing  shows  a  very  simple  electric 
bell  for  use  on  a  bicycle  which  will  make 
people  jump,  thinking  it  is  an  ambulance  or 
an  "electric."  All  that  is  necessary  to 
make  it  is — an  old  door  bell,  a  battery  box, 
(like  the  one  used  with  a  bicycle  electric 
light)  some  No.  12  insulated  wire,  a  clamp, 
and  an  automobile  push  button  (horn). 
It's  very  simple  in  construction.  Direc- 
tion : — Drill  a  hole  in  the  under  side  of 
the  handlebar  at  B,  and  one  on  the  upper 
side  at  J ;  run  the  two  wires  thru  and  con- 
nect to  push  button  A,  clamp  bell  D  to 
frame  I,  with  clamp  E,  but  be  sure  that  it 
is  well  insulated  or  else  the  bell  will  ring 
continuously.  Then  attach  battery  box  H, 
and  run  wires  to  G  and  F,  also  the  push 
button  and  the  bell  is  ready  to  work.  I 
have  been  using  the  bell  described  for 
years,  and  as  you  can  see  at  a  glance,  it  is 
bound  to  be  perfectly  satisfactory.  By  using 
a  two-point  switch  you  can  put  a  light  on 
front  and  rear,  wiring  it  to  the  same 
battery,  as  the  bell  consumes  very  little 
current.  The  bell  may  be  placed  on  a 
motorcycle  and  use  a  storage  battery,  pro- 
viding the  bell  is  heavy  wound. 

Contributed  by 

CLARENCE  SOMERS. 


© 

Every  Bicycle  Owner  Wants  an  Electric  Bell 
Now.    Here's  the  Way  to  Rig  It  Up. 


A  HANDY  RHEOSTAT  FOR  LAMPS 
AND  MOTORS. 

Herewith  is  a  diagram  of  a  simple  and 
quickly  constructed  rheostat.  All  the  fig- 
ures from  1  to  11,  and  all  the  letters  from 
A  to  L,  represent  points  of  the  rheostat, 
which  are  made  by  driving  tacks  so  that 
they  are  about  %"  high  (from  base).  At 
13  and  14  are  two  binding  posts  made  from 
battery  bolts;  11  is  the  movable  contact 
arm.    The  base  is  3"  x  5".    The  tacks  are 


i  ^ — -w^ 

=9J  0 

ill  11               I'm  t 

©  ^3'   '"i  lillfl 

%ll(Pl|Hlll*c^rar1F/  t 

'Willi  — -~m  ■ 

A  Battery  Rheostat  Can  Be  Made  From  a 
Few  Feet  of  Iron  or  Other  Wire  Looped 
Around  Several  Tacks  as  Here  Illustrated. 

driven  in  the  form  of  two  circles;  the  first 
circle  has  a  diameter  of  1"  and  the  other 
circle  has  a  diameter  of  two  inches.  There 
are  12  tacks  on  the  inner  circle  and  10 
tacks  and  2  binding  posts  on  the  outer 
circle.  All  tacks  are  placed  equal  dis- 
tances from  each  other  in  circles.  Now 
connect  A  to  1  to  B  to  2  to  C  to  3  to  D  to 
4,  and  so  on  around  to  10  to  K.  The  wire 
used  is  taken  from  an  old  telephone  in- 
duction coil.  Then  connect  13  and  K  with 
a  piece  of  bell  wire  and  also  14  to  L  to  12 
with  same  size  wire.  Arm  11  can  be  made 
from  a  piece  of  brass  and  12  is  a  brass 
screw  and  two  nuts  from  the  carbon  of  a 
dry  cell  battery.  The  arm  rotates  to  right 
to  increase  current  (from  1  to  11),  and 


A  SIMPLE  ELECTRIC  DOOR 
ALARM. 

A  simple  door  alarm  can  be  made  with 
very  little  cost,  by  first  taking  a  piece  of 


Here's  a  Cheap,  Yet  Efficient  Electric  Door 
Alarm  Switch  Made  From  a  Piece  of  Metal 
Chain  and  a  Brass  Contact  Plate. 

sheet  copper  4  by  5  inches  and  cutting  a 
piece  4  by  1  in.  off  for  the  arm  as  shown 
in  sketch..  Then  fasten  a  piece  of  chain  at 
the  end  of  the  arm  long  enough  so  that 
when  door  is  opened,  it  will  touch  the 
lower  plate  4  by  4  inches  mounted  on  door 
as  shown.  This  closes  the  circuit  which 
rings  the  bell.  The  wire  running  from  the 
door  contact  plate  should  be  soldered  to 
one  of  the  hinges  (F)  and  another  wire 
should  be  soldered  right  on  the  same  hinge, 
and  run  down  to  the  switch  (G),  and  from 
there  to  batteries  (B). 
Contributed  by  A.  GRUETZMACHER. 

decreases  by  rotating  to  left;  to  decrease 
current  (from  11  to  1).   This  rheostat  can 
be  used  for  governing  the  speed  of  small 
motor,  dimming  battery  lamps,  etc. 
Contributed  by  JOHN  WELLS. 


LIGHTING  THE  ICE  CHEST. 

As  my  refrigerator  was  out  on  my  porch 
I  found  that  the  device  described  was  very 
convenient  for  me,  and  by  having  it  out- 
side I  thought  a  wire  attached  to  the  same 
circuit  and  brought  inside  to  an  alarm  bell, 
would  prove  an  excellent  burglar  alarm 


j.e  y  tamp 


Dry  celts , 
1/ 


Door  of  /ce 
chest  ctosedx 


j.s  y.  tamp 


A  Handy  Scheme  for  Fitting  the  Refrigerator 
With    Electric    Light   and    Also   a  Burglar 
Alarm. 

and  it  has  worked  to  perfection.  By  having 
a  refrigerator  so  lighted,  one  can  go  out 
to  it  and  see  what  to  get  without  the  aid 
of  any  other  light. 
Contributed  by  G.  B.  McCARTNEY. 


December,  1917 


THE  ELECTRICAL  EXPERIMENTER 


549 


Under  this  heading  we  publish  every  month 
useful  information,  in  Mechanics,  Electricity 
and  Chemistry,  we  shall  be  pleased,  of 
course,  to  have  our  readers  send  us  any 
recipes,  formulas,  wrinkles,  new  ideas,  etc., 
useful  to  the  experimenter,  which  will  be 
duly  paid  for,  upon  publication,  if  acceptable. 


EXPERIMENTER'S  APHORISMS. 

In  the  following,  we  wish  to  give  to  the 
Experimenter  some  hints  as  to  the  use  of  the 
different  ingredients  and  how  to  work  them: 

(1)  Always  bear  in  mind  that  exact  working 
of  a  formula  requires  ACCURACY,  CLEANLI- 
NESS, PATIENCE,  and  SKILL. 

(2)  Know  what  you  are  about,  before  you 
start  to  experiment.   

(3)  "THE  HISTORY  OF  FAILURES  IS  THE 
HISTORY  OF  SUCCESS"  goes  an  old  adage,  and 
it  applies  well  to  the  experimenter. 

(4)  Many  times  impure,  wrong  or  deterior- 
ated raw  materials,  spell  FAILURE  instead  of 
SUCCESS. 

(5)  A  great  many  of  the  chemicals  and  in- 
gredients required,  cannot  be  obtained  from 
drug  stores;  buy  them  at  a  reputable  supply 
house. 

(6)  BEFORE  CONDEMNING  A  FORMULA, 
be  sure  the  fault  does  not  lie  with  the  manner  of 
handling  it,  or  the  purity  of  the  ingredients. 

(7)  Be  sure  to  mix  the  materials  comprising 
a  certain  formula  in  the  proper  sequence. 

(8)  When  starting  to  prepare  a  mixture, 
especially  one  containing  liquids,  ask  yourself: 
"IS  THE  SPECIFIC  GRAVITY  CORRECT,  AS 
INDICATED  BY  A  HYDROMETER?  IS  THE 
TEMPERATURE  RIGHT?  IS  THE  QUANTITY 
OR  WEIGHT  RIGHT? 

(9)  Acids  and  water,  when  mixed,  should  be 
manipulated  in  the  proper  manner,  i.  e.,  THE 
ACID  SHOULD  BE  POURED  INTO  THE 
WATER,  and  not  vice  versa,  as  the  solution  is 
liable  to  be  forcibly  ejected  from  the  containing 
vessel  and  into  the  mixer's  face. 

(10  For  any  kind  of  SYSTEMATIC  WORK, 
a  floating  THERMOMETER  and  HYDROM- 
ETER, as  well  as  measuring  glasses  and  scales, 
should  always  be  provided,  as  GUESSWORK  is 
EXPENSIVE,  and  SOMETIMES  FATAL. 

(11)  Put  labels  on  ALL  bottles,  boxes  and 
packages  with  FULL  INSCRIPTION  as  to  their 
contents,  it  will  avoid  troubles  and  mistakes. 

(12)  Remember  that  a  beginner  cannot  ex- 
pect to  make  articles  AT  FIRST,  which  will  com- 
pare with  regular  manufactured  products. 


ELECTRIC  WARNING  FOR  POISON 
BOTTLES. 

This  instrument  is  used  in  two  ways  as 
follows :  The  clamps  5  and  6  in  illustration 


When  the  Poison  Bottle  Is  Removed  From 
the  Contact  Strips,  They  Spring  Together, 
Closing   an    Alarm    Bell  Circuit. 


serve  to  fasten  bottle  to  avoid  its  falling 
from  shelf,  and  also  to  notify  an  ignorant 


person  of  the  presence  of  poison.  Proceed 
to  first  construct  upright,  A,  2"  high,  V/2" 
wide,  and  thick.  Fasten  block  to  shelf 
by  screw  1.  At  any  height  put  in  binding 
posts  on  block,  as  shown  in  figure.  Con- 
struct clamps  5  and  6  out  of  old  clock 
springs  heated,  bent  in  above  design  and 
retempered.  These  should  be  constructed 
according  to  the  circumference  of  bottle, 
leaving         between  X  and  Y. 

Connect  spring  arms  at  posts  and  con- 
nect posts  to  batteries  and  warning  bell  as 
indicated  in  figures.  When  at  night,  any- 
one removes  the  bottle  the  springs  come 
together  and  thus  make  contact  accordingly. 
The  bell  rings  as  warning  of  poison. 

Contributed  by  JOHN  WEINZIL,  JR. 


CHEMICAL  GROWTHS  RESEMBLE 
FOLIAGE. 

The  following  item  may  prove  of  inter- 
est to  your  chemical  readers  and  those  who 
dabble  in  chemistry  just  for  the  novelty  of 
such  experiments  as  this : 

A  10%  solution  of  sodium  silicate  (water 
glass)  is  put  into  a  glass  or  beaker,  and 
crystals  of  any  or  all  of  the  following  salts 
are  dropt  in ;  copper  sulfate,  ferrous  sul- 
fate, nickel  sulfate,  cobalt  nitrat.  Many 
other  salts  will  give  similar  results  but  the 
various  sulfates  appear  to  be  the  best. 

Shortly  after  the  crystals  are  placed  in 
the  solution,  they  will  begin  to  grow  in  fan- 
tastic shapes,  each  of  the  salts  giving  a  dif- 
ferent growth  of  different  color.  These 
growths  look  so  much  like  undersea  foliage 
that  they  have  often  been  called  "Submarine 
Gardens." 

The  rate  of  growth  depends  on  the 
strength  of  the  silicate  solution  as  the  crys- 
tals are  due  to  a  formation  of  the  silicate 
of  the  salt  used.  A  solution  of  the  strength 
mentioned  above  allows  the  crystals  to 
grow  in  a  more  even  manner  at  a  rate 
which  can  be  watched.  The  growths,  how- 
ever, will  not  keep  unless  the  solution  is 
very  weak,  and  then  they  grow  too  slowly. 
Contributed  by  JEROME  S.  MARCUS. 


RELATIVE  ELECTRICAL  CONDUC- 
TIVITY OF  DIFFERENT  METALS 


AND  ALLOYS. 

Relative 

Metals  Conduc- 
tivity 

Pure  silver    100. 

Pure  copper    100. 

Refined  and  crystallized  copper   99.9 

Telegraphic  silicious  bronze   98. 

Alloy  of  copper  and  silver  (50%) . . .  86.65 

Pure  gold    78. 

Silicide  of  copper,  4%  Si   75. 

Silicide  of  copper,  12%  Si   54.7 

Pure  aluminum    54.2 

Tin  with  12%  of  sodium   46.9 

Telephonic  silicious  bronze   35. 

Copper  with  10%  of  lead   30. 

Pure  zinc    29.9 

Telephonic  phosphor-bronze    29. 

Silicious  brass,  25%  zinc   26.4 

Brass  with  35%  zinc   21.59 

Phosphor-tin    17.7 

Alloy  of  gold  and  silver  (50%)   16.12 

Swedish  iron    16.4 

Pure  Banca  Tin   15.5 

Antimonial  copper    12.7 

Aluminum  bronze  (10%)   12.6 

Siemens  steel    12. 

Pure  platinum    10.6 

Copper  with  10%  of  nickel   10.6 

Cadmium  Amalgam   (15%)   10.2 

Dronier  mercurial  bronze   10.14 

Arsenical  copper   (10%)   9.1 

Pure  lead    8.88 

Bronze  with  20%  of  tin   8.4 

Pure  nickel    7.89 

Phosphor-bronze,  10%  tin   6.5 

Phosphor  copper,  9%  phos   4.9 

Antimony   3.88 


TWO  USES  FOR  GLASS  IN- 
SULATORS. 

The  accompanying  drawings  show  two 
methods  of  how  glass  telephone  insulators 
and  some  stiff  wire  can  be  so  constructed 
and  utilized  as  useful  receptables  for 
matches,  drills,  screws,  acids,  et  cetera,  in 
any  experimenter's  laboratory.  Figs.  1  and 
2  show  plainly  how  the  wire  is  bent  and 
soldered. 

Contributed  by  JOHN  M.  MUNSONS. 


Handy    Receptacles  for   Matches,   Screws,  Etc., 
Made  From  Wire  and  Glass  or  Porcelain  Insula- 
tors. 


A  FORTUNE-TELLING  EXPERI-  . 
MENT 

Procure  a  cylindrical  carton  about  2]/2 
inches  in  diameter  and  at  least  a  foot  in 
length.  Place  in  the  bottom  of  this  carton 
a  small  bottle,  preferably  an  ink  bottle, 
containing  some  pieces  of  iron  sulfide 
(Fe2S3)  covered  with  either  hydrochloric 
or  sulfuric  acid.  The  cork  of  this  bottle 
should  have  a  hole  about  l/%  inch  in  diam- 
eter drilled  <iiru  it  to  allow  the  escape  of 
the  generated  hydrogen  sulfide  gas.  About 
an  inch  or  so  above  this  bottle  (or  gen- 
erator) a  round  piece  of  perforated  card- 
board is  held  in  place  by  resting  on  four 
common  pins,  the  latter  being  placed  at 
the  ends  of  two  diameters  which  are  per- 
pendicular to  each  other.  These  pins  are 
thrust  thru  the  wall  of  the  carton  so  that 
they  protrude  on  the  inside ;  thereby  form- 
ing a  basis  of  support  for  the  perforated 
cardboard.  The  holes  in  the  latter  should 
be  about  J/s  inch  in  diameter.  Take  a 
pad  of  ordinary  unruled  paper  and  write 
various  fortunes  on  each  sheet  with  a  solu- 
tion of  lead  acetate,  commonly  known  as 
sugar  of  lead.  The  solution  being  colorless, 
the  pad  paper  will  appear  to  have  no  writ- 
ing on  it. 

In  telling  the  fortunes  of  your  friends, 
have  one  of  them  sign  his  or  her  name  on 
the  top  of  a  sheet  of  this  pad.  Tear  this 
sheet  off.  Have  another  friend  place  his 
or  her  name  on  another  sheet  of  the  pad. 
After  having  three  or  four  signed  sheets, 
roll  them  up,  place  them  in  the  carton,  and 
quickly  cover.  Keep  your  friends  interested 
by  quoting  some  magic  patter,  and  after 
placing  the  carton  to  the  four  winds  and 
going  thru  some  magic  motions,  remove  the 
cover  and  take  out  the  roll  of  paper.  Im- 
mediately cover  the  carton.  Then  distribute 
the  sheets  of  paper  to  those  whom  the 
signatures  designate.  Behold!  Your  friends 
will  receive  the  same  signed  sheets  of  paper 
covered  with  black  writing  which  upon 
reading  will  tell  their  fortunes. 

The  chemistry  involved  in  this  experi- 
ment is  the  formation  of  the  black  precipi- 
tate of  lead  sulfide  by  the  generated  hydro- 
gen sulfide  (H2S)  coming  in  contact  with 
the  lead  acetate  Pb(C2H302)2  on  the  paper. 
Pb(C,H30?)2  +  H2S  =  PbS  +  2HC2H3Oa 

Contributed  bv 

FRANK  BECHTOLD,  JR. 


(j/oss        wire  be/ f 
'nsv/a/or.  soldered-.. 

fo  p/ofe  \ 


550 


THE  ELECTRICAL  EXPERIMENTER 


December,  1917 


Experimental  Chemistry 


Laws  of  Chemistry 

THERE  are  certain  laws  of  chemistry 
which  the  reader  should  study  and 
memorize,  previous  to  taking  up 
Electrolytic  chemistry.  There  are 
two  FUNDAMENTAL  LAWS, 
namely,  the  "Law  of  Conservation  of 
Matter"  and  the  "Law  of  Definite  Weight." 
The  Law  of  Conservation  of  matter  states 
that  the  weight  of  the  sum  of  all  the  prod- 
ucts in  an  experiment  is  exactly  equal  to 
the  weight  of  the  sum  of  all  the  factors.  The 


Fig.  93. — Illustrating  the  Law  of  Conserva- 
tion of  Matter  with  Two  Balanced  Test 
Tubes,  Containing  Two  Different  Solutions. 


factors  are  the  substances  used  to  make 
an  experiment ;  the  products  are  the  sub- 
stances obtained. 

Thus,  Hydrochloric  acid  is  the  product 
of  the  combination  of  the  two  factors 
hydrogen  and  chlorin,  expression  of  which 
reaction  is  as  follows : 

H  +  CI  =  HC1  • 
(factors)  (product) 

By  this  law  is  meant  that  chemical  ex- 
periments can  neither  create  or  destroy 
matter.  We  may  form  new  substances, 
separate  elements  from  compounds,  make 
compounds  from  elements,  change  solids  to 
liquids  or  invisible  gases,  and  gases  to 
liquids  or  solids.  We  cannot  create  or 
destroy  matter,  therefore,  matter  is  in- 
destructible and  uncreatable,  as  physics 
teaches  us  that  energy  is.  Amount  of  mat- 
ter is  always  determined  by  weight,  not  by 
volume. 

Properly  understood,  every  equation,  as 
well  as  every  experiment,  illustrates  this 
law.  If  we  were  to  take  any  chemical 
equation  and  count  the  number  of  atoms 
of  any  given  element,  on  the  right  of  the 
equality  sign  (the  products),  we  will  find 
that  it  is  the  same  as  the  number  on  the 
left  (the  factors).  The  compounds  are 
changed,  but  the  atoms  are  the  unchange- 
able things,  as  Dalton  declared  them  to  be 
when  he  named  them  atoms,  which  in 
Greek  means  "uncutable." 

Let  us  now  take  an  equation  and  count 
the  number  of  atoms  on  each  side  of  the 
equation : 

Zn  +  2HC1  =  ZnCl2  +  H2 

(factors)  (products) 

Here  we  find  that  we  have  for  factors,  1 
atom  of  Zinc,  which  reacts  with  Hydro- 
chloric acid,  composed  of  2  atoms  of  hydro- 
gen, and  2  atoms  of  chlorin.  For  products 
from  the  above  factors  we  have   (a)  1 


By  ALBERT  W.  WILSDON 
Nineteenth  Lesson 

molecule  of  Zinc  Chlorid,  composed  of  1 
atom  of  Zinc,  and  2  atoms  of  chlorin,  and 
(b)  2  atoms  of  hydrogen. 

Let  us  now  count  the  number  of  atoms 
for  each  element  and  compound,  and  see 
if  they  are  balanced  in  accordance  with  this 
law.  On  the  left  hand  (the  factors)  we 
have  1  atom  of  zinc,  which  is  also  shown 
on  the  right  hand  as  a  product  contained 
in  the  molecule  of  zinc  chlorid.  As  another 
factor  we  have  2  atoms  of  hydrogen  in  the 
2  molecules  of  Hydrochloric  acid  (2  x  H  = 
2H),  as  a  product  we  have  2  atoms  of 
hydrogen  liberated.  As  another  factor  we 
have  2  atoms  of  chlorin  within  the  2  mole- 
cules of  hydrochloric  acid,  which  is  also 
seen  as  a  product  combined  in  the  Zinc 
Chlorid.  Thus  the  equation  is  properly 
balanced. 

Law  of  Definite  Weight  (also  called  the 
Law  of  Fixt  Proportions). — Any  given 
chemical  compound  always  contains  the 
same  elements,  and  in  the  same  ratio  by 
weight. 

There  are  two  parts  to  this  law.  One  is 
that  a  given  compound  is  always  made  up 
of  the  same  elements.  Hydrochloric  acid 
is  always  composed  of  hydrogen  and 
chlorin,  as  its  ultimate  constituents ;  never 
anything  else.  The  other  part  of  this  law 
is  that  these  elements  always  have  the  same 
ratio  by  weight.  Thus  in  hydrochloric 
acid,  that  ratio  is  1  of  hydrogen  to  35  of 
chlorin — 1:35.  The  ratio  does  not  vary; 
it  is  the  same  as  yesterday  and  always  has 
been  the  same;  it  always  will  be.  The  ex- 
periments which  prove  the  first  part  of  the 
law  prove  the  second  part  also.  Any  chem- 
ical experiment,  in  fact,  illustrates  it. 

The  practical  application  of  this  law  is 
that  if  you  take  too  much  of  one  of  the 
factors  in  making  an  experiment,  only  a 
part  of  the  reaction  will  take  place,  and 
the  excess  will  be  left  behind  unacted  upon ; 
in  some  cases  a  different  substance  from 
that  wanted  may  form. 

In  large  chemical  industries  it  is  almost 


jBflfH 

1  IB 

rig.  95  © 


This  Illustrates  How  Readings  Are  Correctly 
Taken  from  the  "Bottom"  of  the  Meniscus 
In  a  Tube  Containing  a  Fluid. 

as  necessary  to  know  the  right  proportion 
for  mixing  substances  as  to  know  what  to 
put  together.  Suppose  we  wish  to  prepare 
some  ferrous  sulfid   (FeS)   from  its  ele- 


ments ;  in  what  proportion  should  we  mix 
the  latter?  The  equation  which  stands  for 
the  reaction  must  first  be  written: 
Fe+S=FeS.  Next  the  atomic  and  molecu- 
lar weight  must  be  affixt : 

Fe     +       S      =  FeS 
56      -f      32      =  88 
Atomic  Weights  Molecular  Weight 

This  means  that  when  iron  and  sulfur  unite 
to  form  ferrous  sulfid,  56  parts  by  weight 
of  iron  always  unite  with  32  parts  of  sulfur 


Double  Burelle  Clamp 


Fig.  94 


Illustrating  the  Law  of  Fixt  Weight,  Experi- 
ment No.  109,  by  the  Aid  of  a  Double  Burette. 

(or  some  multiple  or  submultiple  of  these 
numbers)  to  form  88  parts  of  ferrous  sul- 
fid. We  should  then  mix  the  elements  in 
the  proportion  of  56  grams  of  iron  to  32 
grams  of  sulfur,  or  7  to  4.  56  to  32  forms 
a  ratio  which  may  be  divided  by  the  com- 
mon factor  8.  Let  us  suppose  we  have  10 
grams  of  iron,  how  much  sulfur  will  com- 
bine with  it? 

The  work  should  be  arranged  as  follows, 
placing  x  under  the  required  or  unknown 
substance  (this  being  Sulfur  in  this  case), 
and  10  under  the  known  or  given  substance 
(Iron  in  this  case). 

Fe    +     S    =  FeS 
56    +    32    =  88 
10  x 

Evidently  there  is  the  same  ratio  between 
56  of  iron  (Fe)  and  32  of  Sulfur  (S)  as 
between  10  of  Fe  and  x  of  S.  This  gives 
the  following  proportion: 

56       :       32       ::       10       :  x 
56  x  =  320 

x  =  5.7 

Proportion  being  an  equality  of  ratios,  we 
have :  56  :  32  : :  10  :  x.  Or  we  may  write 
it 

56  10  or  56    _  32 

32  x  10  x 

All  give  the  same  result.  Thus  5.7  grams 
of  sulfur  are  needed  to  combine  with  10 
grams  of  Iron. 

Again,  we  wish  to  know  how  much  fer- 
rous sulfid  will  be  made?  Arrange  and 
solve  as  follows : 

Fe  +   S   =  FeS      56:  10::  88:  y      15.7  grams  of 
56  +  32   =   88         56y  =  880  FeS 
10        y  y  =  15.7 

(Continued  on  page  559) 


December,  1917 


THE  ELECTRICAL  EXPERIMENTER 


551 


Our  Amateur  Laboratory  Contest  is  open  to  all  readers,  whether  subscribers  or  not.  The  photos  are  judged  for  best  arrangement  and  efficiency 
of  the  apparatus.  To  increase  the  interest  of  this  department  we  make  it  a  rule  not  to  publish  photos  of  apparatus  unaccompanied  by  that  of  the  owner.  Dark 
photos  preferred  to  light  toned  ones.  We  pay  each  month  $3.00  prize  for  the  best  photo.  Make  your  description  brief  and  use  only  one  side  of  the  sheet. 
Address  the  Editor,  '  With  the  Amateurs"  Dept. 


Those  "Electrical  Laboratory"  Photos  !  !  ! 

Well,  "Radio-bugs,"  it  seems  that  you  are  at  last  awakening  to  the  fact  that  your  Uncle  Samuel  has  really  gone  to 
war,  and  that  such  being  the  case,  the  "Radio  Labs.,"  of  more  peaceful  times  have  actually  slipt  into  oblivion,  for  the  time 
being.  Tis  a  mark  of  distinction  to  be  the  owner  of  a  "good"  electrical  laboratory  in  these  times.  Don't  go  about  the 
reorganization  of  your  "Lab."  with  a  half  hearted  spirit.  On  the  contrary,  let  your  motto  be,  "I  will  study  and  observe 
so  that  I  can  be  of  service  to  my  country  when  the  time  comes !"  You  radio  enthusiasts  should  open  up  your  minds 
to  the  vast  possibilities  of  "experimental  electricity."  If  you  possess  a  laboratory  you,  young  man,  may  discover  the 
"germ  "  of  a  far-reaching  electrical  idea  which  would  be  of  inestimable  value  to  Uncle  Sam.  And  you  will  be  rewarded, 
never  fear.  Fortune — Fame — Honor — all  these  come  to  the  genius  who,  by  patient  experiment  and  study  evolves  a  "new 
idea"  that  works.  We  hope  to  hear  from  every  owner  of  an  "Electrical  Lab.,"  with  a  photograph  of  his  favorite  corner, 
as  well  as  a  likeness  of  the  owner.  And  come  to  think  of  it — don't  the  "Girls"  experiment?  Address  the  Editor  "With 
the  Amateur's  Prize  Contest." 


A  GROUP  OF  REPRESENTATIVE  AMERICAN  AMATEUR  LABORATORIES. 

Electrical  Laboratories  of,  1 — L.  W.  Hagerman,  Racine,  Wis.  (Prize  Winner);  2 — Burnie  Lazette,  Monroe,  Mich.;  3 — J.  N.  Edwards,  Blue- 
field,  W.  Va.;  A — Clarence  F.  Kramer,  Lebanon,  Ind.;  5 — Osmond  S.  Ryer,  Pasadena,  Cal.;  6 — Robert  W.  Field,  Owensboro,  Ky.;  7 — Thos. 
D.  Churchill  and  S.  Goldhamer,  Toronto,  Can.    Radio  Stations  of,  8— Jack  Herzog,  Lafayette,  Ind.;  9— Kirk  E.  Smith,  West  Springfield,  Mass. 


552 


THE  ELECTRICAL  EXPERIMENTER 


December,  1917 


i  % 


^TEST  STENTS 


Electric  Bath-Cabinet 

(No.  1,241,234;  issued  to  Honora  C. 
Marrinan.) 
This   combination   electric  heat- 
ing and  hot  water  bath  is  suitably 


thru  which,  the  aerial  and  ground 
lead  wires  pass  to  the  detector. 
These  envelops  or  tubes  also  be- 
come themselves  highly  electrically 
excited  when  oscillations  from  the 
aerial  travel  along  the  lead  wires 
within  them,  and  may  be  connected 
to  other  detectors  having  their  own 
local  circuits  and  translating  in- 
struments, such  as  telephone  re- 
ceivers, etc.,  as  here  indicated. 
Thus,  it  is  possible  with  this  ar- 
rangement to  use  two  detectors 
and  recorders. 


designed  so  that  the  proper  de- 
grees of  heat  can  be  produced  from 
a  series  of  electric  heating  coils, 

E laced  around  the  interior  of  the 
ath  cabinet.  The  heat  reaches 
the  bathing  chamber  occupied  by 
the  person  using  it,  in  the  most 
efficacious  manner  possible.  One 
of  the  principal  features  of  this 
bath  cabinet  lies  in  the  interlock- 
ing electric  switch  and  hot-water 
valve  levers.  The  hot-water  valve 
and  electric  switch  control  is  so  ar- 
ranged that  the  turning  on  of 
said  switch  or  valve  prevents  the 
turning   of   the  other. 

Electric  Automobile-Signal 

(No.    1,238,430;    issued    to    G.  H. 
Nierman.) 
A    semaphore    type    of  electric 
automobile  signal  intended  for  at- 


tachment on  mud-guard  of  such 
vehicles  and  controllable  from  the 
driver's  se'at.  The  hand  or  other 
figure  can  be  moved  to  a  hori- 
zontal position,  as  shown  in  the  il- 
lustration, by  means  of  a  magnetic 
solenoid,  which  is  connected  with 
the  car  storage  battery  or  to  a 
separate  battery,  as  conditions 
may  dictate.  The  movable  hand 
forming  the  signal  is  fitted  with  a 
small  incandescent  lamp  for  night 
signaling,  and  the  lamp  may  be 
cut  out  during  the  day.  The 
solenoid  core  is  connected  to  the 
movable  signal  arm  by  a  flexible 
link  motion  as  shown. 


Intensifier   of  Radio  Oscillations 

(No.  1,235,650;  issued  to  David  W. 
Brown.) 

An  extremely  simple  form  of  in- 
tensifier for  high  frequency  elec- 


Delectors 


Metal  tubes 


trie  oscillations  such  as  occur  in 
wireless  receiving  circuits,  and  in- 
volving simply  the  use  of  two 
metal   tubes,   or   their  equivalent, 


Galvanic  Battery 

(No.  1,240,885;  issued  to  Richard 
Schuster.) 
This  galvanic  cell  employs  two 
electrolytes,  is  said  to  be  odorless, 
and  especially  adapted  for  charging 
storage  batteries.  Its  novel  feature 
resides  in  the  provision  of  a  con- 
tainer or  standpfpe  with  over-flow 
ascending  pipe,  arranged  centrally 
of,  and  in  communication  with  the 


cathode  cell,  for  the  purpose  of 
receiving  the  products  of  decom- 
position given  off  by  the  cathode 
electrolyte.  The  battery  consists 
of  an  outer  jar,  a  porous  cup  con- 
taining the  cathode  electrolyte,  a 
carbon  member,  and  in  the  annular 
space  between  the  jar  and  porous 
cup,  the  anode  electrolyte  and  the 
■annular  zinc  member.  All  of  these 
parts  beingnested  in  a  well-known 
manner.  The  cathode  electrolyte 
consists  of  a  solution  of  biehromat 
of  soda,  water  and  sulfuric  acid. 
The  anode  electrolyte  comprises  a 
caustic  potash  solution  mixed  with 
water.  The  upper  part  of  the 
porous  cup  is  made  impervious  to 
the  electrolyte.  The  cell  gives  2.7 
volt  and  it  is  also  reversible  in 
action. 


Electrical  Detector  for  Under- 
ground Pipes 

(No.  1,241,963;  issued  to  Edward  H. 
Grove.) 

It  is  first  necessary  to  connect  a 
source  of  interrupted  current  to  two 


a  position  at  an  angle  to  the  pipes 
4  and  5.  While  so  holding  the  ex- 
ploring coil,  and  walking  about, 
the  operator  proceeds  to  swing  the 
instrument  in  the  direction  of  its 
length.  When  swinging  the  coil, 
the  operator  may  move  along 
naturally.  When  he  is  directly 
over  the  sought  pipe,  the  sound  in 
the  telephone  receivers  will  be  as 
loud  at  one  limit  of  the  swing  as 
at  the  other. 


(No.  1,241,333;  issued  to  Levi  M. 
Bowman.) 
Another  patent  on  electric  guns, 
and  having  for  its  principal  nov- 
elty the  particular  automatic 
switch  arrangement  shown,  where- 
by the  movement  of  the_  projectile 
along  the  barrel  successively  trips 
the  switch  connecting  in  circuit 
the  coil  just  ahead  of  the  pro- 
jectile. Thus  it  becomes  evident 
how  each  succeeding  magnet  coil 
will  act  on  the  projectile  progres- 
sively, so  that  by  the  time  it 
reaches  the  end  of  the  barrel,  it 
will  have  acquired  a  high  velocity. 


Valve  Receiver  for  Radio  Signals 

(No.  1,238,869:  issued  to  George  M. 
Wright.) 
Receiver  for   radio  signals,  com- 


prising  an  evacuated  vessel  con- 
taining a  heated  filament,  two 
grids  and  an  anode.  The  inventor 
states  that  he  is  thus  able  to  limit 
the  strength  of  the  current  in  the 
anode  circuit,  with  the  result  that 
the  sounds  caused  by  atmospherics 
in  the  telephone  will  be  consider- 
ably reduced,  and  will  thus_  be  pre- 
vented from  over-powering  the 
sounds  caused  by  the  signals 
which  it  is  desired  to  detect. 


Vibrator  for  Electric  Bells 

(No.  1,242,038;  issued  to  W.  E.  R. 
Rademaker.) 
This  patent  covers  a  unique  de- 
sign of  vibrating  interrupter  for 
electric  bells,  which  is  of  such  a 
type   that   it   can  be   made  dust- 


different  taps  on  the  pipe  line,  as 
shown  in  the  diagram.  This 
detector  comprises  a  small  magnet 
coil  connected  to  a  pair  of  sensi- 
tive telephone  receivers,  which  are 
held  to  the  ear.  The  operator  pro-  proof  as  well  as  fool-proof,  and 
ceeds  to  hold  the  detecting  instru-  the  usual  contact  screw  is  done 
ment  by  its  supporting  strap  just  away  with.  The  interrupter  mem- 
above  the  ground  as  in  Fig.  1,  in  ber  of  this  bell  comprises  a  mov- 
COPIES  OF  ANY  OF  THE  ABOVE  PATENTS  SUPPLIED  AT  10c  EACH. 


able  electrode  of  carbon  or  metal, 
delicately  mounted  within  a  small 
tubular  chamber  secured  to  the  bell 
frame.  When  the  circuit  is  closed 
thru  the  bell  and  interrupter,  the 
electro-magnets  are  excited  to 
their  full  maximum  and  the  re- 
sulting vibration  due  to  the  arma- 
ture striking  the  magnets,  jars 
the  interrupter  electrode,  thus 
opening   the   circuit  momentarily. 


Radio   Frequency  Oscillation 
Generator 

(No.  1,240,206;  issued  to  Raymond 
A.  Heising.) 
This  radio-frequency_  oscillation 
generator  is  unique  in  that  no 
spark  gap  is  utilized.  The  high 
frequency  oscillatory  circuit  is 
charged  by  a  rapidly  rotating  com- 
mutator from  a  high-voltage  di- 
rect-current generator,  at  those 
times  during  the  cycle  at  which 
the  difference  of  the  voltage  be- 


tween the  generator  terminals  and 
that  across  the  oscillation  circuit 
is  small.  This  invention  covers 
special  means  for  obtaining  a 
constant  speed  in  the  commutator- 
driving  device;  this  device  com- 
prising an  alternating  current  gen- 
erator, rigidly  connected  to  the 
shaft  with  a  D.  C.  motor  connected 
to  an  external  D.  C.  source  of 
energy. 


Radio  Receiving  Apparatus 

(No.  1,241,565;  issued  to  Harry 
Shoemaker.) 
This  undamped  wave  receptor 
patent  employs  a  small  alternating 
current  generator,  having  a  speed 
adapted  to  produce  alternations  of 
a  frequency  best  adapted  to  oper- 
ate a  telephone  diafram,  say  900 
cycles,  and  the  windings  of  the 
machine  are  so  connected  that  rec- 
tified energy  in  the  detector 
circuit    will    pass    thru    its  field, 


while  the  current  from  its  arma- 
ture will  pass  thru  the  telephone. 
The  telephone  will  then  be  sub- 
jected to  a  sinusoidal  electromo- 
tive-force which  will  be  substanti- 
ally proportional  to  the  current 
flowing  thru  the  fields.  This  in 
turn  will  be  proportional  to  the 
receiving  energy  or  the  number  of 
wave   trains   received  per  second. 


December,  1917 


THE  ELECTRICAL  EXPERIMENTER 


553 


Under  this  heading  are  publisht  electrical  or  mechanical  ideas  which 
our  clever  inventors,  for  reasons  best  known  to  themselves,  have  as  yet 
not  patented.  We  furthermore  call  attention  to  our  celebrated  Phoney 
Patent  Offizz  for  the  relief  of  all  suffering  daffy  inventors  in  this  country 
as  well  as  for  the  entire  universe. 

We  are  revolutionizing  the  Patent  business  and  OFFER  YOU  THREE 
DOLLARS  ($3.00)  FOR  THE  BEST  PATENT.  If  you  take  your  Phoney 
Patent  to  Washington,  they  charge  you  $20.00  for  the  initial  fee  and  then 


Phoney  Patents 


you  haven't  a  smell  of  the  Patent  yet.  After  they  have  allowed  the  Pat- 
ent, you  must  pay  another  $20.00  as  a  final  fee.  That's  $40,001  WE 
PAY  YOU  $3.00  and  grant  you  a  Phoney  Patent  in  the  bargain,  so  you 
save  $43.00 1!  When  sending  in  your  Phoney  Patent  application, 
be  sure  that  it  is  as  daffy  as  a  lovesick  bat.  The  daffier,  the  better. 
Simple  sketches  and  a  short  description  will  help  our  staff  of  Phoney 
Patent  examiners   to   issue  a  Phoney  Patent   on  your  invention   in  a 

jiffy. 


PHONEY  PATENT  OFFIZZ 


PERPETUAL  MOTION  ENGINE.  This  Engine  Runs  on  Air  In- 
stead of  Steam.  The  Engine  Takes  in  Air  At  14.7  Lb.  Pressure 
At  Suction  Pipe  and  Exhausts  the  Same  40  Miles  Above  the  Earth 
Into  a  "Vacuum,"  Or  the  Highly  Rarefied  Upper  Atmospheric 
Strata.    It  Costs  Nothing  to  Run.    Inventor,  Evert  Pool,  Hobart, 

Okla. 


Prize  Winner.— HUN-CATCHER.— Why  Not  Equip  Those  20,000 
Yankee  Aeroplanes  With  Powerful  Electric  Magnets?  The  Mag- 
nets Attract  the  Steel  "Sky-pieces,"  the  Attached  Huns,  Guns, 
Gas  Tanks  and  All.  Dump  'em  in  Convenient  Cages  and  Let  Billy 
Bryan  Talk  the  Kaiser  Out  of  'Em.  Inventor,  Joseph  Wachtman, 
West  Falrvlew,  Pa. 


554 


THE  ELECTRICAL  EXPERIMENTER 


December,  1917 


Question  Box 


This  department  is  for  the  sole  benefit  of  all  electrical  experimenters.  Questions  will  be  answered  here  for  the  benefit  of  all,  but  only 
matter  of  sufficient  interest  will  be  publisht.    Rules  under  which  questions  will  be  answered: 

1.  Only  three  questions  can  be  submitted  to  be  answered. 

2.  Only  one  side  of  sheet  to  be  written  on;  matter  must  be  typewritten  or  else  written  in  Ink,  no  penciled  matter  considered. 

S.    Sketches,  diagrams,  etc.,  must  be  on  separate  sheets.  Questions  addrest  to  this  department  cannot  be  answered  by  mail  tree  of  charge. 
4.    If  a  quick  answer  is  desired  by  mail,  a  nominal  charge  of  25  cents  is  made  for  each  question.    If  the  questions  entail  considerable  re- 
search work  or  intricate  calculations  a  special  rate  will  be  charged.  Correspondents  will  be  informed  as  to  the  fee  before  such  questions  are 

answered. 


AUDION  TICKLER  COIL. 

(861.)  John  Andrews,  Philadelphia,  Pa., 
asks : 

Q.  1.  What  does  the  term  tickler  coil 
mean? 


Hook-up  for  Audion  with  Inductively  Coupled 
"Tickler"  Coil  at  "T." 


A.  1.  There  have  been  a  large  number 
of  experimenters  asking  the  same  question. 

The  term  tickler  coil  refers  to  a  coil 
which  couples  electromagnetically  the  wing 
and  grid  circuits  of  an  Audion,  so  as  to 
make  it  oscillate.  A  standard  circuit  in 
which  a  tickler  coil  is  employed  is  shown 
in  the  accompanying  drawing.  The  coil 
"T"  is  the  tickler  coil  which  is  coupled  to 
the  secondary ;  it  reacts  on  the  grid  circuit 
thru  the  stopping  condenser. 


GASOLINE  ENGINE  QUERY. 

(861-A.)  .  Wilbur  Brown,  Ontario,  Can- 
ada, wishes  to  know: 

Q.  1.  Does  a  two  H.  P.  gasoline  engine 
of  the  marine  type  use  any  more  gasoline 
than  a  gasoline  engine  of  the  hit  and  miss 
type  of  the  same  H.  P.  such  as  used  for 
farm  use. 

A.  1.  It  is  impossible  for  us  to  tell  you 
whether  the  marine  type  engine  draws  more 
gasoline  than  the  other  type  as  the  amount 
of  gasoline  depends  upon  several  factors, 
namely :  load,  leak  of  compression,  due  to 
poor  valve  speed,  type  of  carburetor  and 
the  general  characteristics  of  the  engine. 

Q.  2.  Would  a  %  in.  spark  coil  work  any 
better  or  carry  any  farther  in  a  ground  tele- 
graph system  than  a  buzzer. 

A.  2.  A  Y\  inch  spark  coil  would  work 
better  than  a  buzzer  for  a  ground  telegraph 
system. 

Q.  3.  How  many  glass  plates  3j4  x  3j4 
will  be  required  for  a  condenser  to  be  used 
on  an  Oudin  coil  3  inches  in  diameter  and 
consisting  of  about  500  turns  of  No.  35 
double  cotton  covered  wire. 

A.  3.  Twenty-five  plates  will  be  required. 


AUDION  PHENOMENA. 

(862.)  John  Pils,  Chicago,  111.,  inquires: 
Q.  1.  What  is  the  exact  action  that  takes 

place  in  an  Audion  when  used  as  a  rectifier 

of  radio  frequency  currents,  or  amplifier  of 

audio  frequency  currents? 

A.  1.  It  would  be  impossible  for  us  to 

give  you  an  exact  explanation  of  the  phe- 


nomena that  take  place  in  an  Audion  in 
this  column.  The  general  operating  charac- 
teristics of  this  device  depends  upon  the 
relation  which  exists  between  the  potential 
on  grid  and  the  current  in  the  plate  or  wing 
circuit  with  respect  to  the  filament.  A  very 
thoro  treatise  of  the  operating  characteris- 
tics of  the  Audion  has  been  publisht  in  the 
August,  1916,  issue  of  this  magazine.  It  is 
worth  35  cents  a  copy. 

I  ODD  PHOTOS  WANTED  AT  I 
jj  $1.00  EACH  !  !  !  jj 

S.     Now  is  the   time   to   make  your  jj| 

II  Kodak  pay  for  itself  in  a  real  practi-  g 
g  cal  way.  We  are  after  interesting  8 
g  photographs  of  out-of-t he-ordinary  g 
g  electrical,  radio  and  scientific  sub-  jjj 
=  jects  and  are  willing  to  pay  $1.00  cash  g 
H  for  every  one  we  can  use.  Please  jj 
g  bear  in  \inind  that  for  half-tone  re-  g 
S  production  in  a  magazine,  a  photo-  H 
g  graph  should  be  particularly  sharp  g 
g  and  clear.  Of  course,  if  a  subject  g 
g  happens  to  interest  us  particularly  g 
g  well,  we  can  have  the  photo  retouched.  = 
g  For  the  general  run  of  subjects,  how-  g 
=  ever,  it  does  not  pay  to  go  to  such  g 
g  expense,  therefore,  please  take  pains  g 
g  to  properly  focus  and  expose  your  g 
=  pictures.  It  often  happens  that  a  g 
B  really  mediocre  subject  well  photo-  = 
g  graphed  wins  approval  over  an  ex-  g 
g  cellent  subject  poorly  photographed,  jS 
g  And  don't  send  us  plate  or  film  "nega-  H 
g  tives" ;  send  unmounted  or  mounted  g 
g  "prints,"  perferably  a  light  and  a  dark  g 
e=  one.  g 
g  As  to  what  to  photograph:  Well,  g 
H  that's  hard  for  us  to  say.  We  leave  g 
U  that  up  to  you,  and  every  reader  now  g 
§i  has  the  opportunity  to  become  a  re-  g 
g  porter  of  the  latest  things  in  the  realm  g 
g  of  Electricity,  Radio  and  Science,  g 
g  But,  please  remember — it's  the  "odd,  g 
g  novel  or  practical  stunts"  that  we  are  g 
g  interested  in.  Every  photo  submitted  g 
g  should  be  accompanied  by  a  brief  de—  g 
g  scription  of  100  to  150  words.  Give  g 
g  the  "facts"- — don't  worry  about  the  g 
g  style.  We'll  attend  to  that.  Enclose  g 
g  stamps  if  photos  are  to  be  returned  g 
g  and  place  a  piece  of  cardboard  in  the  g 
g  envelope  with  them  to  prevent  mutila-  g 
B  tion.  Look  around  your  town  and  g 
g  see  what  you  can  find  that's  interest-  g 

g  Address  photos  to — Editor  "Odd  g 
g  Photos,"  Electrical  Experimenter,  g 
g  233  Fulton  Street,  New  York  City.  g 

CONDENSER  QUERY. 

(863.)  Andrew  Hall,  Pittsburgh,  Pa., 
asks : 

Q.  1.  Between  what  points  on  a  condenser 
scale  does  the  capacity  vary  as  a  linear 
equation  ? 

A.  1.  Between  10°  and  160°. 

Q.  2.  Is  it  possible  to  make  a  condenser 
with  a  zero  capacity  at  zero  scale? 


A.  2.  No,  as  it  is  impossible  to  shield  or 
to  reduce  sufficiently  the  electrostatic  field 
produced  by  the  edges  of  the  plates  when 
the  movable  plates  are  set  zero  degrees  on 
the  scale. 

Q.  3.  How  is  the  Seibt  condenser  built? 

A.  3.  The  Seibt  variable  condenser  is 
made  out  of  one  solid  aluminum  casting 
and  the  plates,  both  movable  and  stationary, 
are  machined  out  from  the  same.  With  this 
process  of  manufacture  the  variable  con- 
denser is  made  very  accurate  and  the  space 
between  plates  is  reduced  very  considerably, 
thus  increasing  the  capacity  of  the  con- 
denser. The  capacity  of  this  type  of  con- 
denser is  much  higher  than  that  of  a  built- 
up  condenser  of  the  same  size. 


PROPERTIES  OF  RUBIDIUM. 

(864.)  Frederick  Handel,  Brooklyn,  N. 
Y.,  writes  the  "Question  Box" : 

Q.  1.  What  are  the  properties  of  rubidium 
metal  ? 

A.  1.  The  specific  gravity  of  the  metal  is 
1.52.  It  melts  at  38.5°  centigrade;  while  at 
10°  it  is  as  soft  as  wax.  It  is  a  lustrous 
silver  white  metal,  with  a  tinge  of  yellow, 
oxidizes  rapidly  in  the  air,  developing  much 
heat  and  soon  igniting.  Volatile  as  a  blue 
vapor  below  a  red  heat.  The  metal  does 
not  keep  well  under  petroleum,  but  is  best 
preserved  in  an  atmosphere  of  hydrogen. 
Next  to  caesium  it  is  the  most  electro-posi- 
tive of  all  metals. 

Q.  2.  Does  lead  acetat  precipitate  from 
neutral  or  acetic  acid  solutions? 

A.  2.  Yes,  the  product  of  the  reaction  is 
a  yellow  lead  chromat  and  the  equation 
shows  the  reaction  between  lead  acetat  and 
sodium  chromat. 

Pb  (GH.O,)  +  Na2  Cr  O,  '= 
Pb  Cr  04  +  2(Na  C.  H3  O,) 


PHANTOM  ANTENNA. 

(865.)  Paul  Heffle,  Detroit,  Mich.,  in- 
quires : 

Q.  1.  Is  it  possible  to  operate  a  tele- 
graph system  by  the  use  of  a  buzzer,  water 
pipe  and  gas  pipe  as  current  lines? 

A.  1.  Yes.  We  advise  you  to  refer  to 
page  318  of  the  September,  1917,  issue  of 
this  magazine. 


Capacity 

Resistance 

Exciting  coii 
>  or  loops 

Indue/once 

® 

Circuit  of  a  "Phantom"  Antenna,  Used  in 
Testing  Radio  Transmitters  in  the  Laboratory. 


Q.  2.  What  are  phantom  antennae  and 
how  are  they  made  up? 

A.  2.  A  phantom  antenna  is  an  artificial 
antenna  which  is  used  in  laboratories  in- 


December,  1917 


THE  ELECTRICAL  EXPERIMENTER 


555 


stead  of  a  real  antenna,  but  which  has  the 
same  electrical  unit  values  as  that  of  a  real 
antenna.  Thus  a  real  antenna  has  resis- 
tance, capacity  and  inductance. 

You  can  build  one  of  these  phantom  an- 
tennae by  connecting  in  series  a  suitable  re- 
sistance, capacity  and  inductance  coil  and 
the  diagram  here  gives  the  hook-up  of 
^uch  an  antenna.  The  Government  however 
forbids  its  use  during  the  duration  of  the 
war. 


TRANSIENT  ELECTRIC 
PHENOMENA. 

(866.)  A.  Wolf,  St.  Paul,  Minn.,  asks: 
Q.  1.  What  are  transient  currents? 
A.  1.  According  to  the  definition  given 
by  Dr.  Louis  Cohen  in  his  elaborate  book 
on  alternating  currents,  the  following  holds 
true:  "If  the  electrical  conditions  of  a 
circuit  are  disturbed  in  any  way,  as  for  in- 
stance by  change  of  the  electrical  constants 
of  the  circuit,  or  a  change  in  the  electro- 
motive force  acting  on  the  circuit,  a  read- 
justment of  the  current  and  potential  in  the 
circuit  will  necessarily  follow.  The  per- 
manent state,  however,  is  not  reached  in- 
stantaneously; it  requires  an  appreciable 
time  interval  before  the  electrical  equili- 
brium is  again  establisht.  The  electrical 
phenomena  which  occur  in  the  time  inter- 
val before  the  permanent  state  is  reached 
again  have  been  properly  designated  Tran- 
sient Electric  Phenomena." 


PERMANENT   MAGNET  AND  AU- 
DION  CIRCUIT. 

(867.)  E.  Davis,  of  Edgewood,  R.  I., 
wishes  to  know : 

Q.  1.  How  can  a  permanent  magnet  be 
used  in  an  Audion  circuit  to  increase  the 
sensitiveness  of  the  device? 

A.  1.  There  is  only  one  possible  place 
wherein  a  permanent  magnet  can  be  utilized 
in  an  Audion  circuit  to  advantage,  and  that 
is  by  placing  the  poles  of  the  magnet  near 
the  Audion  tube,  in  which  case  the  sensi- 
tiveness of  the  device  is  increased  mani- 
fold, the  action  of  which  is  due  to  the  con- 
centration of  the  ionic  stream  which  is 
discharged  by  the  hot  cathode  filament. 
In  this  case  the  amplification  and  rectifica- 
tion of  the  instrument  is  considerably  in- 
creased. 


3,000-MILE  RECEIVING  OUTFIT. 

(868.)  T.  A.  Snyder,  of  Chicago.  111., 
asks : 


fc  Audion 


Hook-Up  for  Audion  Receiving  Set  for  Radio- 
Telegraphy. 


Q.  1.  In  order  that  I  may  receive  from 
a  distance  of  3,000  miles,  what  wireless 
instruments  are  required  for  an  efficient 
set? 

A.  1.  The  following  instruments  will  be 
required  in  order  to  be  able  to  receive  3,000 
miles.  A  very  sensitive  detector,  such  as 
the  Audion,  with  its  accessories,  including 
a  high  tension  or  "B"  battery;  a  filament 
battery;  a  pair  of  high  resistance  (prefer- 
ably 3,000  ohms)  'phones;  a  "grid"  con- 
denser of  .00015  mfd;  a  .001  mfd.,  variable 
air  dielectric  condenser.  A  loose  coupler  of 
the  switch-contact  type,  and  a  loading  coil. 


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556 


THE  ELECTRICAL  EXPERIMENTER 


December,  1917 


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Q.  2.    How  would  you  connect  them? 

A.  2.    Wiring  diagram  is  given  herewith. 

Q.  3.  Do  you  know  of  any  firm  who 
sells  blue-prints — giving  full  information  as 
to  how  wireless  instruments  can  be  made? 

A.  3.  We  would  suggest  that  you  pro- 
cure the  two  books — one  entitled  "How  to 
Make  Wireless  Receiving  Apparatus"  and 
the  other  "How  to  Make  Wireless  Trans- 
mitting Apparatus,"  which  can  be  obtained 
from  our  Book  Department  at  25  cents  each. 


SOLID  ELECTROLYTE. 

). )  Stanley  Dewsnap  of  Springfield, 
Mass.,  wishes  to  know : 

Q.  1.  Can  you  give  me  the  formula  for 
making  the  solid  electrolyte  now  in  use  in 
small  portable  storage  cells  in  connection 
with  pyrometers  of  the  optical  type? 

A.  1.  The  type  of  storage  battery  you 
speak  of,  and  which  is  used  in  the  pyrometer, 
is  a  dry  storage  battery  of  the  portable  type. 
It  can  be  readily  made  by  immersing  the 
regular  storage  battery  plates  in  some  glass 
wool  which  is  thoroly  saturated  with  the 
regular  sulfuric  acid  solution  of  the  proper 
density.  This  mixture  for  making  a  storage 
battery  of  the  dry  form,  has  been  utilized 
abroad  with  great  success. 

Q.  2.  Does  the  use  of  such  an  electrolyte 
require  any  different  type  of  plate? 

A.  2.  The  use  of  this  electrolyte  does  not 
necessitate  a  different  type  of  storage  bat- 
tery plate. 


RECTIFIERS. 

(870.)  William  Lewis,  Rosedale,  Kan- 
sas City,  Kan.,  writes : 


How   Two    Lamps   Can    Be    Controlled  By 
Single-Pole  Snap  Switches  From  Two  Dif- 
ferent Locations. 


Q.  1.  Please  show  in  a  diagram  how  I 
can  control  two  electric  lamps  (12  ft. 
apart)  by  one  pole  (one  circuit)  snap 
switches,  one  switch  upstairs,  and  one 
switch  downstairs. 

A.  1.  We  give  herewith  wiring  diagram 
of  the  scheme  in  question. 

Q.  2.  How  many  rectifier  jars  are 
needed  to  change  110  volts  5  amp.  A.C. 
into  55  volts  D.C.? 

A.  2.  You  require  four  standard  type 
rectifiers  in  order  to  obtain  the  current  you 
desire. 


PHOSPHORESCENT  PAINT. 

(871.)  Edw.  L.  Wagner,  of  Sandpoint, 
Idaho,  asks : 

Q.  1.  What  is  the  composition  (electro- 
lyte and  depolarizer)  of  the  "Radio"  or 
"Tungsten"  flashlight  battery? 

A.  1.  The  chemical  composition  of  the 
depolarizer  as  used  in  these  flashlight  bat- 
teries is  the  commercial  form  of  manganese 
dioxid.  The  electrolyte  is  composed  usually 
of  a  mixture  of  zinc  chloride  and  sal  am- 
moniac in  water.  This  is  used  in  these 
batteries  the  same  as  the  regular  dry  cells. 

Q.  2.  How  to  prepare  phosphorescent 
paint  from  calcium  sulfid? 

A.  2.  The  phosphorescent  paint  used  to- 
day is  made  by  thoroly  mixing  some  phos- 
phorescent calcium  sulfid  with  linseed  oil. 

{Continued  on  page  557) 


WANTED!  RECRUITS  FOR  "GAS 
AND  FLAME"  REGIMENT. 

{This  statement  is  authorized  by  Major 
Atkisson  of  the  Thirtieth  Engineers) . 

THE  ELECTRICAL  EXPERIMEN- 
TER has  been  called  upon  by  the 
commanding  officer  of  the  Thirtieth 
Engineers  to  help  in  mobilizing  the  person- 
nel of  a  "Gas  and  Flame"  Service  Regiment. 
This  regiment  is  being  recruited  now  from 
men  volunteering  for  the  service,  and  will 
be  ready  to  go  "over  there"  by  Thanks- 
giving. 

This  is  a  regiment  for  skilled,  practical 
men,  who  will  be  called  upon  at  once  to 
demonstrate  their  worth  and  skill. 

Enlistment  in  the  "Gas  and  Flame"  Regi- 
ment offers  opportunity  to  skilled  men,  to 
be  used  and  recognized  as  men  skilled  in 
their  trade. 

This  opportunity  should  appeal  to  men 
who  have  previously  felt  that  they  were 
most  needed  at  home,  because  of  their  spe- 
cial training  and  experience. 

The  regiment  will  be  required  in  the  field 
of  operation  to  supervise  the  American  of- 
fensive in  "Gas  and  Flame"  service,  and 
will  be  called  upon  to  instruct  men  all  along 
the  front  in  this  most  important  work. 
Consequently  these  men,  all  volunteers,  will 
be  in  the  thick  of  the  greatest  activities. 

The  Thirtieth  "Engineers"  is  the  pioneer 
regiment  in  the  "Gas  and  Flame"  service. 
Men  who  enlist  now  will  be  leaders  in  the 
Spring  offensive. 

Your  Opportunity — This  organization  will 
require  a  large  proportion  of  men  able  to 
assume  responsibility,  and  to  act  upon  their 
own  initiative  and  individual  judgment. 
There  will  be  opportunities  to  advance  to 
the  higher  non-commissioned  grades.  There 
will  be  opportunities  for  commissions. 

The  "Gas  and  Flame"  service  offers  a  real 
chance  for  red-blooded  Americans  to  get  in 
where  their  efforts  will  give  definite  results. 
In  addition  to  needing  any  men  who  are 
looking  for  just  this  opportunity  to  help  put 
across  the  important  service,  specialists  are 
needed  as  outlined  below. 

Who  Can  Qualify — Chemists  (analytical, 
research  and  manufacturing).  Chemical 
workers,  powdermen,  men  experienced  in 
gas  manufacture,  machinists,  automobile  re- 
pair men,  men  able  to  operate  and  repair 
gas  or  steam  engines,  pipe  fitters,  elec- 
tricians, designers,  interpreters,  carpenters, 
blacksmiths,  plumbers,  boiler-makers  and 
chauffeurs. 

Men  with  long  experience  in  their  trade 
are  especially  desired  to  fill  the  Master  En- 
gineer grades. 

All  men  enlisted  in  the  Thirtieth  must 
have  good  muscular  development  and  be 
capable  of  undergoing  active  service  at  the 
front. 

Men  are  wanted  who  know  how  to  take 
care  of  themselves,  who  are  active,  ener- 
getic, and  have  a  strong  determination  to 
carry  out  any  mission  to  which  they  may  be 
detailed. 

Loyal  American  citizens  with  the  above 
qualifications  between  18  and  40  years  of 
age,  who  have  not  actually  been  called  by 
a  local  board  in  the  draft,  are  eligible  for 
enlistment. 

Officers  Are  Specialists — Colonel  A.  A. 
Fries,  Engineers,  N.  A.,  is  to  be  the  com- 
manding officer  of  the  Thirtieth  Engineers. 
He  is  a  regular  officer  of  the  corps  of 
engineers,  with  many  years'  experience  in 
military  and  civil  engineering.  Colonel 
Fries  is  now  in  France  and  is  "Chief  of  the 
Gas  Service." 

Major  E.  J.  Atkisson,  Corps  of  Engi- 
neers, is  organizing  the  first  battalion  of 
the  Thirtieth  Engineers  at  Camp  American 
University,  D.  C.  He  is  a  graduate  of  West 
Point  and  of  Cornell  University. 

{Continued  on  page  558) 


You  benefit  by  mentioning  "The  Electrical  Experimenter"  when  writing  to  advertisers. 


December,  1917 


THE  ELECTRICAL  EXPERIMENTER 


557 


QUESTION  BOX. 

{Continued  from  page  556) 

The  proportions  between  these  two  chemi- 
cals is  dependent  upon  the  amount  of  light 
desired  to  be  emitted  by  the  phosr increscent 
mixture. 


SYNCHRONOUS  GAP. 

(872.)  Robert  D.  Stewart  of  Cambridge, 
Wis.,  asks  the  following  questions  : 

Q.  1.  What  should  be  the  number  of 
cycles  delivered  by  a  rotary  converter  of  Yz 
K.  W.  to  convert  110  volts  D.  C.  to  80  volts 
A.  C,  best  suited  to  wireless  purposes? 

A.  1.  We  should  advise  that  500  cycles 
should  be  the  most  efficient  frequency  for 
such  a  rotary  converter  to  be  used  in  radio 
work. 

Q.  2.  How  can  the  number  of  cycles 
of  a  rotary  converter  of  such  a  type  be  in- 
creased to  twice  the  number? 

A.  2.  The  frequency  can  be  doubled 
in  a  rotary  converter  by  doubling  the  speed 
of  the  armature. 

Q.  3.  Which  would  be  the  most  ef- 
ficient to  use,  a  synchronous  spark  gap,  or 
a  rotary  spark  gap,  with  such  a  rotary  con- 
verter? 

A.  3.  A  synchronous  spark  gap  is  the 
most  efficient  form  of  spark  discharger  for 
use  in  radio  work,  and  if  a  rotary  disc  with 
projecting  electrodes  is  mounted  on  the 
shaft  of  a  rotary  converter,  a  synchronous 
spark  is  thus  obtained. 


MULTI-LAYER  COIL. 

(873.)  Mr.  B.  A.  Browne  of  Wash- 
ington, D.  C,  writes : 

Q.  1.  I  understand  from  the  article 
"Calculation  and  Measurement  of  In- 
ductance" on  page  320  of  the  September 
issue  of  the  Electrical  Experimenter,  that 
the  multilayer  coil  as  described  in  figures 
2,  3  and  4,  may  be  used  in  lieu  of  a  loose 
coupler.  If  I  am  correct,  will  you  please 
say  how  the  wave  length  is  varied.  The 
description  does  not  seem  to  provide  for 
any  taps  as  in  loose  coupler  construction. 
This  coil  is  described  as  "very  satisfactory 
for  tuning  long  waves."  Will  you  please 
give  the  approximate  minimum  and  maxi- 
mum wave  lengths  that  could  be  received 
with  a  coil  of  this  design,  constructed  as  in- 
dicated on  page  321,  column  1. 
_  A.  1.  The  amount  of  inductance  of  mul- 
tilayer coils  is  varied  in  the  same  way 
as  in  other  types;  that  is,  by  taking  from 
each  layer  a  contact  lead  which  naturally 
controls  the  number  of  turns  in  the  coil;  thus 
controlling  the  wave  length  or  the  circuit 
in  which  the  coil  is  connected.  You  can 
have  as  many  contact  leads  or  "taps"  from 
a  multilayer  coil  as  you  wish.  However,  it 
should  be  carefully  noted  that  the  insula- 
tion between  the  connection  and  its  adjacent 
layer  should  be  very  thoroly  arranged; 
thus  avoiding  any  short-circuits.  The  max- 
imum and  minimum  wave  length  received 
with  such  coils  is  entirely  dependent  upon 
the  other  constants  entering  into  the  oscil- 
latory circuit,  viz.,  the  antenna  inductance 
and  antenna  capacity,  and  the  capacity  used 
across  the  oscillatory  circuit.  It  is  essen- 
tial that  these  factors  be  known  before- 
hand, before  we  can  give  the  maximum  or 
minimum  wave  lengths  that  can  be  had 
with  this  type  of  coil.  However,  you  can 
obtain  wave  lengths  ranging  from  100  to 
10,000  meters  with  this  coil,  providing  the 
proper  capacities  are  used  in  the  circuit. 

Q.  2.  I  understand  from  reading  the 
Electrical  Experimenter  that  a  "tickler 
coil"  is  merely  a  contrivance  to  rapidly  make 
and  break  a  wireless  circuit.    If  I  am  cor- 


These  Are  The  Hours  That  Count 


MOST  of  your  time  is  mortgaged  to  work,  meals  and 
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You  can  do  it  in  one  hour  after  supper  each  night,  right  at  home,  through 
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I 


tion,  or  in  the  subject,  before  which  I  mark  X. 


□  electrical  engineer 

□  Electric  Lighting 
H  Electric  Car  Running 
J  Electric  Wiring 

□  Telegraph  Expert 

□  Practical  Telephony 

□  MECHANICAL  engineer 

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□  Concrete  Builder 

□  Structural  Engineer 

□  PLUMBING  AND  HEATING 

□  Sheet  Metal  Worker 

□  CHEMICAL  ENGINEER 


□  SALESMANSHIP 

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□  Commercial  Law 

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□  GOOD  ENGLISH 

□  Teacher 

□  Common  School  Subjects 

□  CIVIL  SERVICE 

□  Railway  Mail  Clerk 

□  Textile  Overseer  or  Supt. 

□  Navigator  □Spanish 
Q  AGRICULTURE      □  German 

□  Poultry  Raining     □  French 

□  AUTOMOBILES      □  Italian 


Name   

Occupation 
&  Employer . 

Street 

and  No  


City. 


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558 


THE  ELECTRICAL  EXPERIMENTER 


December,  1917 


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rect  in  this,  will  you  tell  me  how  this 
operation  enables  the  reception  of  un- 
damped waves  with  detectors  that  will  not 
otherwise  render  such  waves  audible? 

A.  2,  The  exact  function  of  the  tickler 
coil  is  c;iven  in  Query  No.  861,  and  is  that 
a  direct  magnetic  coupling  between  the 
wing  and  grid  circuit  of  the  Electron  relay 
or  Audion  tube  is  obtained,  which  functions 
serve  as  the  means  of  transferring  the  plate 
current  to  the  wing  circuit,  which  grid 
current  is  strengthened  by  the  addition  of 
a  charge  on  the  grid ;  thus  increasing  the 
amplifying  or  regenerative  effect  of  the 
tube.  The  only  means  by  which  oscillat- 
ing conditions  can  be  had  is  by  coupling 
both  of  these  circuits  and  the  tickler  coil 
together.  In  other  words,  energy  trans- 
ferred and  retransferred  from  both  of 
these  circuits,  and  the  rapidity  of  this 
transformation  of  energy  is  so  high,  that 
an  oscillatory  current  of  high  frequency  is 
obtained,  which  must  occur  in  the  "beat' 
reception  of  undamped  waves. 


WOMAN  WINS  WIRELESS  TEST. 

It  fell  to  a  young  woman  to  make  the 
highest  average  at  a  government  examina- 
tion for  wireless  operators.  She  made  the 
highest  of  anybody — man  or  woman — in 
Baltimore  city. 

Immediately  after  the  declaration  of  war 
with  Germany  ten  pretty  girls  decided  to 
take  up  wireless  telegraphy  in  order  that 
they  might  be  able  to  take  the  places  of  the 
boys  called  to  serve  their  country  at  the 
front.  They  all  now  have  a  government 
license,  and  one  of  them  received  the 
highest  average  made. 


WANTED!  RECRUITS  FOR  "GAS 
AND  FLAME"  REGIMENT. 

{Continued  from  page  556) 

All  officers  have  been  carefully  selected 
from  the  Regular  Army  and  from  civil  life, 
with  a  view  to  their  special  fitness  for  this 
particular  service.  They  are  experienced 
chemical,  gas  and  military  engineers. 

How  to  Enlist — Go  to  the  nearest  recruit- 
ing station  or  U.  S.  District  Engineering 
Office,  state  fully  and  clearly  your  qualifica- 
tions and  that  you  wish  to  be  enlisted  in 
the  Thirtieth  Regiment  of  Engineers  (Gas 
and  Flame). 

The  officer  in  charge  will  examine  you 
physically  and  pass  upon  your  qualifications 

If  accepted,  you  will  be  enlisted  and  im- 
mediately sent  to  headquarters  of  the  Thir- 
tieth Regiment  of  Engineers  at  Camp 
American  University,  D.  C. 

All  men  must  first  enlist  as  privates,  the 
rate  of  pay  being  $33.00  per  month  and  ex- 
penses. Men  with  the  necessary  experience 
may  be  assigned  to  special  duties  and  given 
non-commissioned  rank  at  rates  of  pay 
ranging  from  $40.20  to  $96.00  per  month 
and  expenses.  The  latter  include,  for  both 
privates  and  non-commissioned  officers,  food, 
clothing,  medical  attendance  and  transpor- 
tation. Those  who  enlist  will  be  eligible 
immediately  for  promotion,  according  to 
their  ability  and  as  openings  occur.  Men 
who  enlist  now  will  have  excellent  oppor- 
tunities for  promotion  as  the  service  ex- 
pands. 

Everybody  Can  Help — 

1.  If  not  qualified  for  enlistment,  get  at 
least  one  man  to  volunteer.  You  can  be 
an  immense  help  in  this  way,  even  if  you 
yourself  are  not  in  a  position  to  serve. 

2.  Get  this  announcement  printed  in  your 
local  newspapers.  This  is  exceedingly  im- 
portant. 

3.  Manufacturers,  see  that  a  few  men  of 
your  organization  respond  to  this  call. 

4.  Use  this  page  as  a  poster  in  your  office, 
or  ask  us  for  reprints. 


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December,  1917 


THE  ELECTRICAL  EXPERIMENTER 


559 


EXPERIMENTAL  CHEMISTRY. 

(Continued  from  page  550) 
Again,  suppose  we  want  to  know  how 
much  oxygen  will  combine  with  a  piece  of 
charcoal  weighing  7  grams?  Also  how 
much  Carbon  dioxid  (COa)  ■  will  form? 
Arrange  and  solve  as  follows : 


St 

12  + 


2  0  =  COa 

2x16  =  12  +  2x16 

32  =  44 
x  y 


12 


:  7 
12x 


32  : 

224 

18.66 


12 


:  7 
12y 
y 


44  : 

308 
25.66 


Thus  18.66  grams  of  Oxygen  are  required 
and  25.66  grams  of  Carbon  dioxid  (C02) 
are  formed. 

Always  have  the  final  weight  numbers 
(as  12,  14,  32,  44  as  above)  on  the  same 
horizontal  line;  and  be  sure  your  equation 
balances;  then  it  is  only  necessary  to  use 
such  numbers  as  the  equation  calls  for.  Re- 
sults must  be  given  in  decimals  to  one  or 
two  places — not  in  common  fractions. 

Suppose  we  want  to  obtain  2  liters  of 
Oxygen.  How  many  grams  of  Potassium 
Chlorat  (KC108)  must  we  employ,  if  a 
liter  of  oxygen  weighs  1.43  grams?  This 
question  may  be  solved  as  follows : 


KC103 
39  +  35  +  48 
122 


KC1  +  30 
39  +  45  +  3x16 
74  48 


Weight  of  O  required, 
1.43  g.  x  2  =  2.86  g. 


122  :  x  ::  48  :  2.86 
48x  =  248.92 
x  =  5.18 


In  working  out  problems  according  to  the 
preceding  models,  observe  the  following 
order : 

1.  Write  and  balance  up  the  equation. 

2.  Affix  the  weights  to  such  of  the  sub- 
stances as  are  called  for. 

3.  Put  in  the  proper  places  under  the 
given  weights,  the  weights  to  be  used,  plac- 
ing x,  y,  or  z  for  the  wanted  substances. 

4.  Make  a  proportion,  using  the  sub- 
stances involved. 

5.  Place  the  product  of  the  means  equal 
to  that  of  the  extremes. 

6.  Find  the  value  of  x,  y,  or  z. 

EXPERIMENT  NO.  108.  Illustrating 
the  Law  of  Conservation  of  Matter.  (Quan- 
titative.) 

Have  2  test  tubes  and  wind  a  fine  cop- 
per wire  around  the  neck  of  each,  leaving 
a  loop  to  hang  them  from  one  arm  of  a 
hornpan  or  other  balance.  Arrange  the 
balance  so  that  it  can  be  easily  adjusted; 
then  pour  into  one  tube  5  cc.  of  a  solution 
of  lead  nitrat  (Pb(N08)2),  and  into  the 
other  an  equal  volume  of  sodium  chlorid 
solution  (common  salt),  the  exact  amount 
is  not  essential  in  either  case.  Be  sure 
there  is  no  liquid  on  the  outside  of  the 
tubes.  Fasten  the  tubes  to  the  bottom  of 
one  beam  of  the  scales  (See  Fig.  93)  and 
weigh  the  tubes  and  their  contents,  or  coun- 
terbalance them,  noting  the  weight. 

Now  carefully  detach  the  tubes,  pour  the 
contents  of  one  into  the  other  without 
spilling,  note  the  effect  produced,  and  then 
hang  them  again  on  the  beam.  In  case 
there  is  not  equilibrium,  try  the  work  over 
again  with  more  care. 

Here  we  have  two  factors  to  begin  with, 
i.  e.,  a  solution  of  lead  nitrat  and  a  solution 
of  salt.  These  will  be  found  to  have  a  cer- 
tain weight,  when  weighed  or  counterbal- 
anced upon  the  scales.  These  are  then 
mixed  and  a  chemical  change  is  effected. 


Count  the  atoms  in  each  substance,  and 
see  if  they  are  balanced  on  each  side  of  the 
equation.  When  the  small  2  is  placed  after 
the  brackets,  as  in  lead  nitrat,  it  means  that 
both  the  elements  within  them  must  be 
multiplied  by  two.  When  a  2  is  placed  be- 
fore a  substance,  as  in  sodium  chlorid,  it 
means  that  all  the  elements  following  it 
(not  beyond  a  plus  or  equality  sign)  must 
be  multiplied  by  two. 

TABLE. 

INTERNATIONAL  ATOMIC  WEIGHTS 
The  following  is  a  complete  list  of  the  81  ele- 
ments, with  symbols  and  atomic  weights,  in  which 
0  =  16,  H  =  1.008. 

ATOMIC 
WEIGHT. 
27.1 
120.2 
39.9 
74.96 
137.37 

9.1 
208.0 
11.0 
79.92 
112.40 
132.81 
40.09 
12.00 
140.25 
35.46 
52.0 
58.97 
93.5 
63.57 
162.5 
167.4 
152.0 
19.0 
157.3 
69.9 
72.5 
197.2 
4.0 
1.008 
114.8 
126.92 
193.1 
55.85 
83.0 
139.0 
207.10 
7.00 
174.0 
24.32 
54.93 
200.0 
96.0 
144.3 
20.0 
58.68 
14.01 
190.9 

16.00 
106.7 
31.0 
195.2 
39.10 
140.6 
226.4 
102.9 
85.45 
101.7 
150.4 
44.1 
79.2 
28.3 
107.88 
23.00 
87.62 
32.07 
181.0 
127.5 
159.2 
204.0 
232.42 
168.5 
119.0 
48.1 
184.0 
238.5 
51.0 
130.7 
172.0 
89.0 
65.37 
90.6 


DOES 
YOUR 


STOMACH  BALK? 


ELEMENT. 
Aluminum 
Antimony 
Argon 
Arsenic 
Barium 
Berylium 
Bismuth 
Boron 
Bromin 
Cadmium 
Caesium 
Calcium 
Carbon 
Cerium 
Chlorin 
Chromium 
Cobalt 
Columbium 
Copper 
Dyprosium 
Erbium 
Europium 
Fluorine 
Gadolinum 
Gallium 
Germanium 
Gold 
Helium 

Hydrogen 

Indium 

Iodin 

Iridium 

Iron 

Krypton 

Lanthanum 

Lead 

Lithium 

Lutecium 

Magnesium 

Manganese 

Mercury 

Molybdenum 

Neodymium 

Neon 

Nickel 

Nitrogen 

Osmium 

Oxygen 

Palladium 

Phosphorus 

Platinum 

Potassium 

Praseodymium 

Radium 

Rhodium 

Rubidium 

Ruthenium 

Samarium 

Scandium 

Selenium 

Silicon 

Silver 

Sodium 

Strontium 

Sulfur 

Tantalum 

Tellurium 

Terbium 

Thallium 

Thorium 

Thulium 

Tin 

Titanium 

Tungsten 

Uranium 

Vanadium 

Xenon 

Ytterbium  (Neoytterbium) 

Yttrium 

Zinc 

Zirconium 


SYMBOL. 

Al 

Sb 

A 

As 

Ba 

Be 

Bi 

B 

Br 

Cd 

Cs 

Ca 

C 

Ce 

CI 

Cr 

Co 

Cb 

Cu 

Dy 

Er 

Eu 

F 

Gd 

Ga 

Ge 

Au 

He 

H 

In 

I 

Ir 

Fe 

Kr 

La 

Pb 

Li 

Lu 

Mg 

Mn 

Hg 

Mo 

Nd 

Ne 

Ni 

N 

Os 

O 

Pd 

P 

Pt 

K 

Pr 

Ra 

Rh 

Rb 

Ru 

Sa 

Sc 

Se 

Si 

Ag 

Na 

Sr 

S 

Ta 

Te 

Tb 

Tl 

Th 

Tm 

Sn 

Ti 

W 

U 

V 

Xe 

Yb 

Yt 

Zn 

Zr. 


Pb(NOa)2    +  2NaCl 
(factors) 


PbCla    +  2NaNOs 
(products) 


EXPERIMENT  NO.  109.  Illustrating 
the  Law  of  Fixt  Weight.  (Quantitative.) 

Have  2  graduated  burettes  arranged  as 
in  Fig.  94.  Have  one  of  these  nearly  filled 
with  very  dilute  Hydrochloric  acid  (HC1) 
(C.  P.  acid  with  about  10  times  its  volume 
of  water).  Into  the  other  pour  approxi- 
mately the  same  volume  of  sodium  hydroxid 
solution  (NaOH).  This  solution  can  be 
made  by  dissolving  5  grams  of  Caustic  soda 
(Continued  on  page  571) 


STRONGFORT 
The  Pcrlect  Man 

....  Dr. 
rvard  Vni- 


thlete  of 
Hm 

ty  hat 


Saruent  of 
■uertitv  ■ 
"He 


unqueationalill/  tlte 
finest  specimen  of  phueicul 
development  ever  seen. 


ARE  vnu  afmia  of  it? 
L\  Is  if  a  mystery? 
X  X  What  (Jo  you  know 
about  it?  What  service 
is  it  giving  you?  You  are 
no  stronger  than  your 
stomach  1  Your  capacity 
for  work,  your  endurance, 
your  mental  keenness, 
are  all  dependent  upon 
Whether  y  0  u  r  stomach 
functions  soundly  and 
does  its  shore  in  pro- 
ducing pure  blood  for  tho 
heart  to  send  to  all  pails 
or  the  body,  energizing 
tho  m  i  n  d.  and  putting 
"Pep"  in  every  thought 
and  action. 

DOES  YOUR 
HEART  MURMUR, 
SKIP  AND 
FLUTTER? 

Do  you  know  that  your 
heart,  is  also  menaced  by 
a  deranged  stomach?  If. 
instead  of  properly  di- 
gesting your  food,  it  is 
allowed  to  remain  in  the 
stomach  to  sour  and  fer- 
ment, the  gases  thus 
generated  hy  the  decom- 
position will  swell  your 
abdominal  region  unnat- 
urally, interfering  with  all 
the  organs,  and  bringing 
the  pressure  thus  caused 
principally  against  the 
heart.  It  is  this  con- 
dition that  is  responsible 
for  many  of  the  fatal,  so- 
called  cases  of  Heart 
Failure. 

You  can  correct 

this  with 
STRONGFGRTISM— 


NOT  WITH  DRUGS  AND  PILL  PIFFLE ! 

If  your  stomach  is  in  good  condition  ynu  can 
digest  anything,  and  then  your  natural  appetite 
will  call  for  the  food  your  body  needs.  The  Stomach 
is  a  muscular  organ  and  its  perfect  functioning  de- 
pends upon  maintaining  a  normal  muscular  activity. 
This  is  where 

YOU  NEED  MY  HELP  ! 

This  is  where  my  study  of  anatomy  and  the  in- 
ternal organs  becomes  so  valuable.  I  have  devised 
methods  which  bring  about  such  an  internal 
muscular  development  so  that  the  functioning  can 
be  controlled,  thus  giving  you  full  control  of  your 
health. 

It  is  not  what  you  eat,  but  what  you  are  able 
to  digest  that  gives  you  the  vitality  to  do  things. 
Stop  pampering  your  stomach.  It  is  the  STRONU- 
FORT  Methods  that  you  need,  based  on  the  true 
principles  of  Nature's  laws  of  health  and  body 
building. 

I  AM  A  BUILDER  OF  MEN 

TOUR  whole  body  can  be  rebuilt,  I  will  show 
you  how  to  help  Nature  and  replace  the  old  worn, 
'decaying  cell  life  and  rebuild  it  with  new  vital 
tissue.  No  matter  what  your  weakness  may  be, 
whether  it  has  been  brought  on  by  i?idigestion, 
gassy  stomach,  nervousness,  or  by  youthful  indiscre- 
tions, my  natural  methods  will  correct  it.  If  you 
are  SKINNY,  run  down,  bilious,  always  tired  and 
sleepy,  have  headaches,  rupture,  no  "Pep,"  you 
need  the  STROX<;FOKT  Methods.  Every  bodily 
ill  gives  way  to  the  gentle,  healing  and  building 
influences  of  my  System.  Mark  the  ailment  that 
interests  you  most  on  the  coupon  below,  and  I  will 
send  you  personal  information  that  will  help  you. 

It  will  cost  you  nothing  to  consult  me — it  may 
save  your  life.  Send  TODAY  for  my  book.  "In- 
telligence in  Physical  and  Health  Culture."  It  is 
a  liberal  education  on  tho  subject  and  will  show 
you  tli e  way  to  perfect  Health,  Long  Life,  Sucoess 
and  Happiness.  It  is  FREE.  Send  Cc  in  stamps 
to  cover  mailing  expenses.    Write  NOW. 

LIONEL  STRONGFORT 

MASTER  OF  PHYSICAL  CULTURE 

361  PARK  BLDG.,  NEWARK,  N.  J. 
Personal  consultation  by  special  appointment  only. 

 FREE  CONSULTATION  COUPON 

Bear  Strongfort: — Please  send  me  your  boob 
"INTELLIGENCE  IN  PHYSICAL  AND  HEALTH 
CULTURE,"  for  postage  of  which  I  enclose  6 
cents  in  stamps. 

I  have  marked  (X)  before  the  subject  in  which 
I  am  interested  and  should  like  you  to  send  me  a 
personal  talk  on  this  subject. 
.  Thinness 
. .  Obesity 


.  Nervousness 
.  .  Neuritis 
. .  Insomnia 
.  .  Biliousness 
.  .  I  ndigestion 
.  .Torpid  Liver 
.  .Constipation 

Short  Wind 
. .  Flat  Chest 

Colds 
. .  Catarrh 
.  .  Poor  Circulation 
. .  Heartweakness 
. .  Headache 
.  .Skin  Disorders 
. .  Lung  Trouble 

Name   


.Rheumatism 
Round  Shoulders 
Stoop  Shoulders 
.  Deformity  No.  361 

.  Rupture 
Youthful  Errors 
Devitalizing  Losses 
.  I  mpotency 
.  Despondency 
.Poor  Memory 
Flat  Feet 
.Increased  Height 
.Muscular  Development 
.Great  Strength 
.Weight  Lifting 
.Advanced  Course 
.  Many- Weight  Barbell 


Street   

City   State. 


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560  THE  ELECTRICAL  EXPERIMENTER  December,  1917 


A  NEW  NERNST  VAPOR  LAMP. 

Prof.  W.  Nernst  describes  a  vapor  lamp 
in  recent  German  patents  which  is  some- 
what similar  to  Darrah's  lamp,  and  is  a 
decided  improvement  from  the  point  of 
view  of  efficiency. 

According  to  the  patent,  the  lamp  in- 
cludes a  spherical  bulb,  as  shown  in  Fig. 
1,  which  contains  the  two  carbons  a  and  b. 
The  upper  electrode  is  connected  to  the 
iron  core  of  a  solenoid,  c,  which  is  suitably 
protected  against  the  chemical  effects  of 
the  vapor.  The  lower  end  of  the  spherical 
bulb  ends  in  a  short  closed  tubular  con- 
nection, which  contains  the  salt  to  be  va- 
porized. The  volatilization  is  effected  by 
an  external  source  of  heat;  for  this  pur- 
pose the  series  resistance,  to  which  the 
lamp  is  connected,  may  be  suitably  used. 

In  a  second  patent  Prof.  Nernst  de- 
scribes a  vapor  lamp  in  which  the  main 
conducting  medium  is  mercury  vapor ;  a 
suitable  salt  is  added  in  order  to  give  a 
better  color  to  the  light.  The  principle  of 
the  lamp  consists  in  adding  a  line  spec- 
trum to  that  of  the  mercury  vapor ;  in  this 
way  a  white  light  is  produced.  Mercury 
vapor,  however,  has  the  property  of  con- 
tinually removing  any  foreign  substances. 
It  is,  therefore,  possible  to  introduce  the 
coloring   substance   continuously,    if  such 


A  New  Form  of  Vapor  Lamp  In  Which  a 
Salt  or  Mercury  Is  Vaporized  by  Electrical 
Heat. 


substances  are  used  as  fuse  at  the  tempera- 
ture of  the  mercury  vapor  lamp.  The  sub- 
stances thus  continuously  volatilize  with 
the  mercury,  subsequently  condensing  and 
flowing  back  into  the  circuit  in  order  to 
begin  a  fresh  cycle  of  operations.  In  Fig. 
2  this  lamp  is  shown,  consisting  of  a  glass 
bulb  containing  the  electrodes.  The 
anode  is  of  mercury,  and  the  cathode  con- 
sists of  a  small  carbon,  K,  which  is  con- 
nected to  the  core  of  a  solenoid.  It  is 
necessary  to  prevent  the  condensed  drops 
of  mercury  and  salt  from  reaching  the  arc, 
and  therefore  small  conical  pieces  of  glass 
are  fused  into  the  vessel,  and  surround  the 
carbon.  The  falling  drops  then  volatilize 
on  the  surface  of  the  mercury.  Another 
conical  glass  piece  is  placed  above  the  mer- 
cury in  order  to  lead  the  vapor  to  the  arc. 
If  a  strong  current  passes,  the  mercury 
vapor  rises  rapidly  from  the  arc,  and  this 
causes  a  sucking  movement  at  the  lower 
ends,  which  takes  a  sufficient  quantity  of 
the  salt  vapors  with  it.   A  specially  suitable 


salt  mixture  for  these  lamps  is  said  to 
consist  of  70  per  cent,  zinc  chlorid,  15 
per  cent,  calcium  chlorid,  5  per  cent,  thal- 
lium chlorid,  5  per  cent,  lithium  chlorid  and 
5  per  cent,  caesium  chlorid.  A  lamp  of 
this  kind  without  a  series  resistance  gives 
a  light  of  3,000  hefner  c.p.  on  120  volts;  it 
takes  4  amperes,  and  therefore  has  an 
efficiency  of  0.16  watt  per  hefner  candle- 
power,  which  is  a  considerable  improve- 
ment on  other  electric  lamps.  The  num- 
bers of  the  German  patents  are  288,228 
and  288,229. 


MANY  GENIUSES  ARE  NEVER 
REWARDED. 

By  Dr.  Leonard  Keene  Hirshberg,  A.B., 
M.A.,  M.D.  (Johns  Hopkins  Univ.) 

CONSIDERING    the    relatively  poor 
salaries  Uncle  Sam  pays  in  Wash- 
ington, the  Government  certainly  has 
made  some  splendid  investments — not  to 
say  obtained  bargains — in  many  of  its  em- 
ployees. 

Almost  from  the  beginning  of  the  Gov- 
ernment it  has  been  the  general  rule  that 
a  department  employee  who  made  an  in- 
vention need  not  turn  it  over  to  the  de- 
partment with  which  he  was  associated. 
In  the  Department  of  Agriculture  this  is 
one  of  the  established  rules,  and  the  War 
and  the  Navy  Departments  also  have  pro- 
mulgated a  similar  regulation.  But,  de- 
spite all  this,  it  is  the  unwritten  law — 
which  is  more  powerful  than  that  on  the 
statute  books — that  a  Government  employee 
shall  not  make  money  out  of  his  inven- 
tions. The  Government  and  the  people  at 
large,  therefore,  reap  a  valuable  harvest  of 
inventions  each  year  which  cost  them  noth- 
ing and  add  immeasurably  to  the  public 
wealth  and  comfort. 

One  of  these  inventors  is  Dr.  Marion 
Dorset,  biochemist  of  the  Bureau  of  Ani- 
mal Industry.  He  is  the  man  who  first 
isolated  the  germ  that  is  responsible  for 
cholera  in  the  hog.  Then  he  invented  a 
serum  to  combat  it.  Dr.  Dorset  protected 
his  processes  by  patents  and  then  turned 
them  over  to  the  public.  But  anyone  who 
chooses  is  at  liberty  to  manufacture  and 
use  this  serum  without  paying  a  penny  of 
tribute.  It  is  an  absolute  anti-toxin.  It 
is  estimated  that  this  discovery  of  Dr. 
Dorset's  is  saving  the  nation  about  $15,- 
000,000  a  year  in  the  one  branch  of  its 
food  supply. 

Dr.  Dorset  is  also  the  inventor  of  a 
secret  ink  used  by  the  Government  in 
stamping  meats  that  have  been  past  upon 
by  the  Federal  inspectors  in  the  packing 
houses.  Prior  to  Dr.  Dorset's  discovery 
the  Government  was  paying  a  private  firm 
$60,000  a  year  for  metal  tags  for  the  same 
purpose.  The  ink  is  far  more  effective, 
for  it  puts  the  stamp  into  the  meat  itself. 
It  cannot  be  transferred.  Dr.  Dorset  re- 
ceives a  salary  of  $3,500  a  year. 

The  problem  of  grain  standardization 
used  to  be  considered  almost  impossible 
of  solution.  But  a  year  ago  J.  W.  T. 
Duvel,  one  of  the  Government's  experts, 
discovered  that  there  was  a  variation  in 
the  weight  of  grain  of  from  5  to  25  per 
cent.,  due  to  the  amount  of  moisture  it 
contained.  This  was  a  very  important 
matter,  because  grain  grown  in  a  damp 
country  would  have  an  advantage  of  about 
20  per  cent,  over  grain  grown  in  a  dry 
climate.  Dr.  Duvel's  researches  resulted 
in  his  inventing  a  moisture  tester,  by  which 
the  percentage  of  humidity  in  grain  can 
be  ascertained  in  a  very  few  minutes. 
This  invention  is  now  in  use  in  every  grain 
elevator  in  America.  Not  a  cent  in  royal- 
ties is  paid  to  anyone  for  it. 


The  Government  sends  out  about  70,000,- 
000  packets  of  seed  a  year.  It  used  to 
cost  the  Government  $1.32  a  thousand  for 
the  mechanical  work  of  filling  these  packets 
with  seed.  J.  E.  W.  Tracy,  of  the  Bureau 
of  Plant  Industry,  invented  a  device  for 
the  filling  of  these  packets.  This  has 
reduced  the  cost  of  this  work  by  about 
one-fourth  and  saves  the  Government  a 
good  many  thousand  dollars  a  year.  It 
also  saves  the  seedsmen  a  lot  of  money, 
for  the  machinery  can  be  made  and  used 
by  anyone  without  paying  a  penny  for 
tribute. 

Logan  W.  Page,  director  of  the  office 
of  good  roads  in  the  Department  of  Agri- 
culture, gave  to  the  world  not  long  ago 
an  invention  of  a  waterproof  cement,  which 
is  of  great  structural  value  in  the  build- 
ing of  locks  and  dams.  It  has  played  an 
important  part  in  the  construction  of  the 
Panama  Canal.  It  is  so  valuable  to  many 
large  industries  that  its  inventor  could 
have  sold  it  easily  for  a  great  sum  of 
money.  A  cement  is  produced  that  will 
make  an  otherwise  porous  structure  water- 
tight. Floors  covered  with  this  cement  are 
damp-proof. 

"Dedicated  to  the  Public"  are  the  four 
words  printed  at  the  head  of  the  patents 
issued  three  years  ago  to  Major  George 
Owen  Squier,  Chief  Signal  Officer  of  the 
Army  Signal  Corps.  His  invention  is  revo- 
lutionizing the  existing  system  of  telephone 
communications.  He  might  have  sold  it  for 
a  vast  sum,  but  he  gave  it  to  the  world  for 
nothing. 

The  value  of  many  of  the  great  in- 
ventions of  the  officers  of  the  War  and 
Navy  Departments  can  be  actually  proved 
only  when  the  nation  comes  in  contact 
with  some  other  power.  One  of  the  most 
important  of  these  inventions  that  has  been 
given  outright  to  the  United  States  is  the 
disappearing  gun  carriage.  This  was  in- 
vented by  Generals  Buffington  and  Cro- 
zier. 

Major  O.  M.  Lissak  of  the  regular  army 
is  the  inventor  of  a  machine  for  the  manu- 
facture of  cartridge  clips.  This  machine 
has  been  in  use  in  the  Government  arsenals 
for  many  years.  It  is  estimated  that  it 
has  saved  the  Government  something  like 
$40,000  a  year.  Major  Lissak  derived  no 
benefit  from  his  invention  until  about  nine 
years  ago,  when  a  bill  was  introduced  in 
Congress  awarding  him  a  lump  sum  of 
$25,000. 

In  the  General  Land  Office  there  is  a 
chief  clerk  named  Frank  Bond.  He  is 
a  geographer  and  takes  a  deep  interest  in 
American  exploration.  Long  ago  he  con- 
ceived the  idea  that  a  map  that  would  show 
at  a  glance  just  what  the  early  explorers 
had  done  would  be  of  great  interest  and 
value.  Nothing  of  the  sort  was  in  ex- 
istence. Mr.  Bond  spent  years  in  making 
this  map,  which  is  of  great  historical 
value.  It  became  especially  important 
when  some  changes  were  made  in  the  offi- 
cial maps  involving  the  boundaries  of  the 
territory  included  in  the  Louisiana  pur- 
chase. Then  it  was  found  that  Bond's 
original  researches  were  far  more  authori- 
tative and  exact  than  any  that  had  been 
made  before.  As  an  aid  to  the  study  of 
the  development  and  exploration  of  the 
United  States,  Mr.  Bond's  map  has  been 
of  so  much  value  that  it  has  been  asked 
for  by  practically  every  school  and  library 
in  the  United  States. 

The  forecasting  of  the  rise  and  fall  of 
the  tides  at  thousands  of  different  places 
is  a  very  complicated  and  intricate  proc- 
ess. It  is  one  of  the  important  parts  of 
the  work  done  by  the  Coast  and  Geodetic 
Survey.  Nineteen  different  elements  enter 
into  each  calculation.    Figuring  this  out 


December,  1917 


THE  ELECTRICAL  EXPERIMENTER 


561 


with  paper  and  pencil  used  to  be  a  tre- 
mendous task.  It  required  an  expense  for 
clerical  labor  that  came  to  about  $40,000  a 
year. 

Thirty  years  ago  William  Farrell,  an  em- 
ployee of  the  Coast  and  Geodetic  Survey, 
devised  a  machine  for  this  purpose.  He 
turned  this  invention  over  to  the  Govern- 
ment, and  it  has  been  used  ever  since. 
He  never  has  received  any  revenue  from 
it.  The  machine  automatically  figures  the 
time  and  degree  of  maximum  and  mini- 
mum tides  at  any  moment  of  the  day  or 
night  and  at  any  place  along  the  coast 
of  the  United  States.  It  takes  only  one 
man  to  operate  it. 

In  the  Treasury  Department  at  Washing- 
ton there  is  an  ingenious  apparatus  which 
mechanically  enumerates  paper  money  in 
a  fraction  of  time  required  for  counting 
by  hand.  It  is  the  recent  invention  of  a 
mechanical  expert  of  that  department,  and, 
like  all  other  devices,  is  free  for  public 
use.  It  is  being  extensively  adopted  by 
banks  and  business  houses. 


THE  DETECTION  OF 
SUBMARINES. 

At  the  present  time  it  is  of  the  highest 
importance  that  those  capable  of  assisting 
in  the  problem  of  detecting  enemy  sub- 
marines should  know  something  of  the  diffi- 
culties that  must  be  overcome  and  the  con- 
ditions under  which  the  submarines  usually 
operate.  In  this  connection  the  following 
memorandum,  which  has  been  publisht  in 
the  "Mining  and  Scientific  Press,"  of  San 
Francisco,  by  the  American  Committee  of 
Engineers  in  London  should  be  useful. 

The  Engineering  Committee  of  the  Na- 
tional Research  Council  issues  the  following 
data  to  guide  those  desirous  of  helping  to 
circumvent  the  enemy's  submarine  cam- 
paign by  means  of  invention  and  suggestion. 
Any  communication  on  the  subject  should 
be  addrest  to  Mr.  W.  F.  Durand,  vice- 
chairman  of  the  Committee,  at  Washington, 
D.  C. 

Submarines  operate  singly  or  in  groups, 
as  may  seem  best  suited  to  local  or  special 
conditions. 

They  are  supposed,  where  circumstances 
favor,  to  lie  on  the  bottom  at  rest  and  with 
listening  devices  attempt  to  detect  the  ap- 
proach of  vessels.  On  receipt  of  evidence 
that  a  vessel  is  approaching  they  rise  to  a 
level  permitting  observation  with  periscope, 
and  then  maneuver  accordingly.  When  in 
water  too  deep  to  permit  lying  on  bottom 
the  submarine  must  maintain  steerage  way 
in  order  to  hold  its  level  of  submergence. 
The  minimum  speed  at  which  this  can  be 
done  will  range  with  circumstances  from  2 
to  4  knots.  The  maximum  depth  of  sub- 
mergence is  about  200  ft.  The  usual  depth 
of  running  is  from  50  ft.  to  100  ft. 

They  have  been  supposed  to  return  to  the 
home  base  at  intervals  of  30  to  35  days. 
The  total  radius  of  action  will  presumably 
range  from  5,000  to  8,000  miles  at  a  mod- 
erate cruising  speed  of  10  or  11  knots.  The 
high  speed  emerged  will  range  from  14  to 
18  knots,  or  possibly  more  in  latest  designs. 
The  maximum  submerged  speed  is  about  10 
knots. 

The  time  required  from  emergence  to 
submergence  will  range  from  one  to  three 
or  four  minutes,  according  to  circumstances. 
When  submerged  near  the  surface,  the  time 
required  to  raise  the  periscope,  take  a  quick 
observation  and  lower  it  again,  may  range 
from  15  to  30  seconds.  If  desired,  the  sub- 
marine can  follow  an  undulating  path,  ris- 
ing and  submerging  alternately,  at  frequent 
intervals,  at  will.  Or  otherwise  it  may  run 
fully  submerged  but  near  the  surface,  and 
take  frequent  observations  thru  the  peri- 
scope.   Modern  submarines  are  provided 


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THE  ELECTRICAL  EXPERIMENTER 


December,  1917 


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with  two  or  three  periscopes.  The  loss  or 
destruction  of  one,  therefore,  will  not  nec- 
essarily disable  the  boat. 

Torpedoes  fired  from  submarines  are  pre- 
sumably aimed  by  changing  the  direction  of 
the  boat.  This,  however,  is  not  assured  in 
all  cases.  The  torpedo,  in  order  to  run  true, 
must  travel  at  an  immersion  of  about  10  ft. 
In  smooth  water  it  may  be  run  at  a  shal- 
lower depth  than  in  rough  water. 

Submarines  may  operate  at  night  with 
less  liability  of  detection,  but  with,  of 
course,  greater  difficulty  in  picking  up  their 
target. 

Submarines  use  the  gyroscopic  compass. 

Sounds  produced  by  the  movement  of  a 
submarine  thru  the  water,  including  those 
traceable  to  the  propeller,  to  movements  of 
the  rudder,  etc.,  should  permit  of  detection 
by  the  use  of  the  modern  refined  sound 
letecting  devices. 

The  distance  at  which  a  protecting  net, 
ilate  or  shield  or  other  means  of  exploding 
he  torpedo  before  reaching  the  side  of  the 
.hip  must  be  located  in  order  that  such  dis- 
ance  will  render  the  effect  of  the  torpedo 
larmless,  will  depend  primarily  upon  (1) 
weight  of  explosive  charge,  (2)  depth  of 
orpedo  when  exploded,  (3)  strength  of  the 
.hip's  structure.  With  modern  torpedoes 
ind  a  depth  of  10  ft.  or  12  ft.,  and  with 
the  structure  of  modern  merchant  ships, 
listances  of  20  ft.  or  30  ft.  would  perhaps 
be  required  in  order  to  give  good  assurance 
igainst  injury.  With  rough  water  and  pos- 
sibly much  less  submergence  at  the  time  of 
explosion,  reduced  distances  of  15  ft.  or  20 
ft.  might  prove  sufficient.  Experimental  in- 
vestigations on  this  subject  show  a  very 
.vide  divergence  among  the  results,  and  no 
precise  rule  can  be  given.  It  may  be  ad- 
led,  however,  that  naval  constructors  gen- 
erally are  satisfied  that  the  distance  at 
which  protecting  plates  or  shields  would 
lave  to  be  placed  in  order  to  secure  im- 
munity is  so  great  as  to  render  their  use 
of  very  doubtful  practicability. 


GOVERNMENT  WANTS  RADIO 
MEN. 

Orders  were  received  at  the  Topeka, 
Kansas,  naval  recruiting  office  recently  au- 
thorizing the  recruiting  officer  to  enlist  men 
and  boys,  who  have  completed  the  high 
school  course  or  its  equivalent,  in  the  radio 
naval  reserve  corps. 

There  are  100  vacancies  to  be  filled  from 
this  district.  The  men  accepted  for  this 
service  will  be  sent  to  one  of  the  state 
universities  on  the  eastern  coast,  where  they 
will  receive  a  four  months'  training  in  wire- 
less telegraphy. 

A  number  of  the  state  universities  in  the 
east  have  offered  their  equipment  in  this 
department  and  have  given  the  services  of 
their  instructors  to  the  government  for  this 
purpose.  Upon  the  completion  of  the  four 
months'  course  the  applicants  will  be  as- 
signed to  duty  on  board  a  man-of-war. 
They  will  be  honorably  discharged  from 
further  duty  upon  the  termination  of  hos- 
tilities. 


RADIO  PLANT  FOR  ANNAPOLIS 

Annapolis  will  soon  have  a  wireless  sta- 
tion as  powerful  as  that  at  Arlington. 

A  high  naval  official  admitted  recently 
that  the  money  for  the  erection  of  this 
monster  radio  station,  approximating  not 
less  than  $1,000,000,  has  already  been  set 
aside  and  that  the  work  of  installing  the 
tower  and  its  equipment  will  commence  at 
once  on  the  Naval  Academy  grounds. 


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December,  1917 


THE  ELECTRICAL  EXPERIMENTER 


563 


AN    "INDUCTION"  ELECTRIC 
WATER  HEATER. 

The  induction  electric  water  heater  here 
illustrated,  is  made  in  sizes  from  750  watts 
to  500  K.  W.  In  previous  heaters  of  this 
type,  the  power  factor  has  been  so  low 
as  to  make  them  of  no  commercial  value. 
In  this  appliance,  however,  the  power  fac- 
tor has  been  brought  to  between  75%  and 
80%. 

The  heater  consists  of  a  cast  iron  core 
thru  which  the  fluid  to  be  heated  passes, 
laminated  "U"  shaped  sections  surround- 
ing the  ends  of  the  core  on  two  sides  and 
a  circulating  primary  coil  thru  which  the 
exciting  current  passes,  the  whole  being 
enclosed  by  a  suitable  casing. 

The  induced  energy  has  been  found  by 
test  to  be  wholly  due  to  hysteresis  and 
eddy  currents  in  the  solid  cast  iron  core, 
which  in  turn  heats  the  fluid  of  a  cir- 
culating system  into  which  the  heater  is 
introduced.  In  the  resistance  type  of 
heater,  there  is  always  a  chance  that  the 


This  Induction  Electric  Water  Heater  Is  In- 
tended for  Use  on  Radiators,  etc.  It  Involves 
the  Use  of  a  Coil  Thru  Which  A.  C.  Passes, 
Which  Causes  a  Water  Heating  Member  to 
Become  Heated  by  the  Current  Induced  in  It. 

resistance  will  burn  out.  This  generally 
happens  sooner  or  later,  and  when  it  does 
-the  only  thing  to  do  is  to  get  a  new  heater 
or  heating  element.  The  induction  heater, 
on  the  other  hand,  is  practically  indestruct- 
ible, the  primary  coil  being  of  such  large 
size  wire  that  there  is  no  danger  of  it 
burning  out.  Pure  asbestos  insulation  is 
used  thruout  which  cannot  deteriorate  with 
age  or  heat.  The  properties  of  cast  iron 
are  such  that  just  before  the  metal  be- 
comes heated  to  the  point  of  deformation, 
it  loses  its  magnetic  qualities,  thus  being 
automatically  self-protecting.  After  cool- 
ing, the  iron  again  crystallizes  and  has 
all  of  its  former  magnetic  properties. 

In  recently  investigated  cases  where  the 
induction  heater  has  replaced  gas,  it  was 
-found  that  at  $4.00  per  K.W.  per  month 


(4  mills  per  watt),  it  was  about  one- 
third  less  than  gas  at  $1.00  per  thousand 
feet. 

The  engineering  principles  involved  in 
the  construction  of  this  heater  do  not  limit 
its  application  to  simply  supplying  hot 
water  for  household  use,  but  it  can,  with 
very  little  change,  be  applied  to  hot  water 
and  steam  heating.  Where  hot  water  or 
steam  systems  are  already  installed,  it  is 
only  necessary  to  connect  the  heater  in 
place  of  the  boiler. 

After  a  careful  investigation,  it  is  found 
that  each  kilowatt  of  capacity  in  induction 
electric  heaters  will  supply  20  sq.  ft.  of 
hot  water  radiation.  For  low  pressure 
steam  heating  one  kilowatt  will  supply 
\2l/i  sq.  ft.  of  radiation. 

Further,  the  induction  principle  here  in- 
volved applies  itself  efficiently  to  a  melt- 
ing pot  for  the  Linotype  and  other  type 
casting  machines. 


SOME  DISCOVERIES  NOT  MADE 
BY  TEUTONS. 

During  the  last  few  months  I  have 
heard  the  Germans  arraigned  as  blatant, 
boorish,  barbaric,  writes  Townes  R.  Leigh 
in  the  Cincinnati  Enquirer,  yet  in  nearly 
every  case  the  speakers  suffixed  to  their 
invectives  such  an  expression  as :  "But 
when  it  comes  to  brains  you  will  have  to 
hand  it  to  them;  they  have  made  science." 

Why  hand  it  to  them?  What  epoch- 
making  invention  or  discovery  is  of  Ger- 
man origin,  except  a  stamp  on  which  is  in- 
scribed "Made  in  Germany?"  The  steam 
engine  has  been  called  the  greatest  of  all 
inventions.  It  broke  the  shackles  from 
slaves ;  it  mingled  the  marts  of  the  world ; 
it  made  neighbors  of  the  antipodes.  New- 
comen,  a  native  of  Devonshire,  England, 
obtained  the  patent  for  the  first  partially 
successful  steam  engine ;  Watt,  a  Scotch- 
man, perfected  it ;  Cuynet,  Murdock  and 
Trevithick  brought  forward  the  locomo- 
tive, not  on  German  soil ;  Stephenson,  an 
Englishman,  was  the  first  to  apply  the  lo- 
comotive steam  engines  to  railways  for 
passenger  traffic;  France,  England  and 
America  applied  it  to  navigation. 

The  telegraph,  which  brings  us  the  daily 
history  of  the  world,  was  invented  by  an 
American,  Professor  Morse,  who  also  sug- 
gested the  Atlantic  cable,  which  was  sub- 
sequently laid  by  that  American  merchant- 
scientist,  Cyrus  W.  Field,  assisted  in 
"mooring  the  new  world  alongside  of  the 
old"  by  Lord  Kelvin,  the  prince  of 
physicists,  a  British  subject.  Alexander 
Graham  Bell,  the  inventor  of  the  really 
practical  telephone,  was  born  in  Scotland 
and  grew  to  fame  in  America.  A  young 
Italian,  Marconi,  gave  commercial  wireless 
telegraphy  to  the  world. 

Cyrus  McCormick,  a  native  of  West  Vir- 
ginia, produced  the  reaping  machine  which 
harvests  the  food  of  the  world ;  Meikle, 
of  England,  brought  forth  the  thrashing 
machine;  thus  was  famine  banished.  Eli 
Whitney  of  Massachusetts  parentage,  in- 
vented the  cotton  gin ;  Hargraves,  an  Eng- 
lishman, made  the  spinning  jenny;  Ark- 
wright,  also  English,  supplied  its  deficiency 
with  his  famous  spinning  frame;  the  Eng- 
lishman Kay,  introduced  the  fly  shuttle  in 
weaving;  Brunei,  who  devised  the  knitting 
machine  and  Cartwright,  inventor  of  the 
power  loom,  were  British  subjects.  Thus 
was  the  world  clothed. 

Altho  Germany  is  militaristic  and  wor- 
ships at  the  shrine  of  Mars,  what  votive 
offering  has  she  made  to  the  God  of  war? 
It  was  not  she  who  contributed  gunpow- 
der, smokeless  powder,  percussion  cap, 
nitro-glycerin,    guncotton,    dynamite,  tor- 

(Continued  on  page  566) 


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ELECTRICAL  ENGINEER 

Electrician 

Electric  Wiring 

Electric  Lighting 
w  Elec-.ric  Car  Running 
J  Heavy  Electric  Traction 

□  Electrical  Draftsman 

□  Electric  Machine  Designer 

□  Telegraph  Expert 

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□  MECHANICAL  ENGINEER 
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□  Machine  Shop  Practice 

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□  CIVIL  ENGINEER 

n  Surveyingand  Mapping 
MINE  FORKM'N  ORENWtt 
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564 


THE  ELECTRICAL  EXPERIMENTER 


December,  1917 


TWO  NOVEL  ELECTRIC 
INSPECTION  LAMPS. 

The  small  automatic  inspection  lamp 
here  shown  in  use  has  been  brought  out 
by  a  Boston  inventor,  for  use  especially 
by  physicians  and  dentists.  This  lamp  con- 
sists of  an  extremely  small  battery  case 
and  lamp  holder  to  which  is  attached  a 
wooden  tongue  depressor.  When  in  use 
the  pressure  of  the  tongue  on  the  de- 
pressor actuates  the  switch  element,  light- 
ing the  lamp;  when  removed  from  the 
mouth  the  depressor  automatically  opens 
the  lamp  circuit. 


One  of  the  Latest  Electric  Mouth  Inspection 
Lamps  Intended  for  Dentists  and  Physicians. 
It  Carries  a  Tongue  Depressor. 

This  lamp  is  equipt  with  100  interchange- 
able wooden  tongue  depressors,  and  takes 
the  regular  pencil  battery.  By  its  use  the 
physician  has  the  free  use  of  one  hand, 
as  it  only  requires  one  hand  to  hold  the 
lamp  and  tongue  depressor  combined,  and 
the  construction  allows  it  to  be  so  held, 
that  the  hand  does  not  obstruct  the  view 
of  the  throat. 

The  same  inventor  has  perfected  the 
small  lamp  and  magnet  shown  in  the  ac- 
companying illustration,  and  which  is  in- 
tended for  use  about  automobiles  and  other 
machinery  to  pick  up  small  metal  parts 
that  cannot  be  reached  by  the  hand.  The 
magnet  end  of  this  device  is  provided  with 
a  110- volt,  4  candlepower  bulb  for  illumi- 
nating the  part  inspected  or  the  location 
where  a  piece  of  metal  is  to  be  picked  up. 
The  outfit  is  18  inches  long  and  provided 
with  a  suitable  length  of  cord  which  can 
be  attached  to  any  lighting  socket.  The 
magnet  part  is  detachable,  so  that  the  lamp 
can  be  used  alone  when  such  use  is  desir- 
able. 


WHY  SOME  KISSES  THRILL! 

An  eminent  psychopath  has  likened  a  kiss 
to  the  stroking  of  a  cat,  and  says  that  the 
longer  you  kiss  the  same  woman  the  less 
thrill  you  get  in  return. 

Love  is  an  electro-chemical  action,  and 
he  who  says  the  same  effect  that  is  de- 


rived from  a  kiss  can  be  obtained  from 
the  stroking  of  a  cat  is  a  theorist,  and  is 
taking  into  consideration  only  the  electro 
part  of  the  action.  It  is  likely  that  the 
learned  psychopath  is  not  a  man  from  the 
great  school  of  experience,  or  that  he  has 
never  been  fortunate  enough  to  come  in 
contact  with  the  human  magnet  that  did 
not  repel  him. 

Compare  two  human  beings,  male  and 
female,  with  two  large  storage  batteries 
highly  charged.  The  action  to  which  the 
batteries  are  subjected  wears  them  out  as 
time  goes  on.  They  work  harmoniously, 
and  so  it  is  with  a  man  and  a  woman. 
So  long  as  she  is  magnetic  she  draws  the 
man  to  her,  and  the  same  thrill  is  there ; 
but  once  she  begins  to  repel,  then  the  mag- 
net ceases  to  perform  its  functions  and 
the  thrill  is  gone. 

Who  would  be  satisfied  to  stroke  the 
back  of  a  pretty  cat  to  bring  about  the 
thrill  they  have  experienced  when  brought 
in  contact  with  the  magnet  that  attracted 
them  ? 

When  the  chemical  elements  in  a  man 
and  a  woman  blend  properly  that  is  when 
they  are  mated ;  the  kiss  never  loses  its 
thrill. 

Chicago  Herald. 

We  showed  the  above  clipping  to  our 
office  boy,  "Fips,"  and  asked  him  for  his 
opinion,  he  being  self-admittedly  well 
versed  and  experienced  in  all  matters  (and 
manners)  of  osculation. 

After  "Fips"  had  digested  the  clipping 
by  means  of  two  bottles  of  dyspepsia 
tablets,  he  scratched  his  tousled  red  head 
thoughtfully  with  his  lower-most  hind  leg, 
and  after  partaking  a  fresh  slice  of  "Rare- 
mint"  chew-chew  gum,  he  spake  thusly : 

"Everything  being  electrical  in  this 
world,  why  not  the  kiss?  Does  it  not 
tingle  like  a  galvanic  current?  Is  there, 
as  a  rule,  not  a  lot  of  juice  behind  it?  Does 
it  not  require  a  good  deal  of  pressure 
(voltage)  ?  Does  it  not  often  result  in  a 
shock — when  SHE  "pastes"  you  one  on 
your  "lamps,"  in  other  words,  when  the 
fuse  blows  out? ! 

But  from  an  academic  standpoint  the 
kiss  really  is  a  direct  short-circuit  of  pas- 
sion— neat  definition  that,  what?  I  might 
add  that  the  kiss  also  very  often  acts  as 
a  sort  of  electrical  safety  valve.  Take  two 
highly  charged  human  animals,  man-)-, 
woman — ;  if  the  potential  was  allowed  to 
rise  indefinitely  either  individual  might 
blow  up.  Hence  nature  in  its  wisdom  pro- 
vided the  kiss,  which  acting  as  a  safety 
valve,  neutralizes  the  +  and  —  electricities, 
by  allowing  both  currents  to  surge  back 
and  forward  thru  the  valves,  i.e.,  lips.  If 
one  application  does  not  bring  down  the 
potential  to  the  safety  level,  why,  dog-gone 
it,  switch  'er  on  some  more  ! ! 

The  Chicago  Herald's  critic,  however, 
picked  out  an  unfortunate  example  when 
he  compared  man  and  woman  to  "large" 
storage  batteries.  Did  not  the  poor  simp 
know  that  storage  batteries  contain  ACID  ? 
How  can  they — man  and  woman — be  ex- 
pected to  "work  harmoniously"  when  they 
are  full  of  sulfuric  acid?!  My,  my!  How 
can  a  kiss  survive  a  constant  acid  bath? 
No  wonder  the  thrill  becomes  less  and  less ! 
No  wonder  that  sooner  or  later  a  "galvanic 
internal  action"  sets  in,  reducing  the  cur- 
rent strength  to  almost  zero !  And  what 
about  those  internal  short-circuits,  present 
in  all  storage  cells,  particularly  in  human 
ones :  selfishness,  distrust,  disloyalty,  dis- 
interestedness, dissatisfaction? 

These  not  only  completely  discharge  the 
storage  battery,  but  make  it  often  impos- 
sible to  ever  recharge  the  cells  again,  just 
as  in  a  real  storage  battery.  The  plates 
have  become  thoroly  sulfated  by  this  time, 
covered  with  a  thick  coating.    Result:  the 


human  animal  by  this  time  has  become  en- 
tirely and  hopelessly  callous.    Hence,  if  a 
kiss  is  ever  attempted  in  this  state,  no  cur- 
rent can  flow — consequently  no  thrill. 
Moral:  If  you  must  kiss, — Stroke  a  cat! 


MIND  READING  BY  WIRELESS. 

While  traveling  in  Ohio  last  year,  writes 
a  commercial  telegrapher,  I  attended  a  per- 
formance in  a  small  town,  where  a  mind 
reader  was  giving  a  wonderful  exhibition 
of  his  powers.  The  mind  reader,  apparently 
an  Oriental,  for  he  wore  a  turban  and  spoke 
broken  English,  was  able  to  name  every  ob- 
ject the  audience  chose  to  select  for  a  test; 
he  also  named  dates  on  coins,  words,  and 
read  passages  in  books  and  newspapers ;  it 
was  a  marvelous  exhibition. 

The  mind  reader's  assistant  had  a  familiar 
look;  he  reminded  me  of  a  telegraph  opera- 
tor I  had  worked  with  in  the  West.  When 
he  came  to  where  I  was  sitting  I  noticed  he 
kept  one  hand  in  his  side  coat  pocket.  The 
assistant  asked  me  to  give  the  mind  reader 
a  test. 

Pulling  out  my  Union  card,  I  asked  him 
to  name  the  organization  of  which  I  was  a 
member.  It  was  three  minutes  by  my  watch 
before  the  mind  reader  answered,  "Broth- 
erhood of  Railroad  Signalmen." 

The  assistant  turned  away  from  me  as  he 
held  my  card  in  such  a  way  as  to  bring  the 
side  where  his  hand  was  in  the  coat  pocket 
away  from  me. 

Thirty  years  as  a  telegrapher  has  made 
my  hearing  wonderfully  acute  and  I  de- 
tected faint  Morse  signals.  Then  I  realized 
in  an  instant  why  the  mind  reader's  assis- 
tant kept  his  hand  in  his  coat  pocket.  He 
had  a  wireless  buzzer  in  there  and  was  sig- 
naling the  mind  reader.  The  buzzer  was 
muffled  with  cloth  to  kill  the  sound. 

I  also  saw  why  the  mind  reader  wore  a 
turban  and  stood  rigid  in  one  position  on  a 
rug.  The  turban  was  to  hide  the  receivers 
clamped  on  his  ears  and  the  rug  to  hide  the 
antennae  that  ran  under  it  and  up  behind 
his  back  to  the  receivers. 

I  changed  my  seat  several  times  so  as  to 
be  near  the  assistant ;  and  every  time  I 
heard  the  same  faint  Morse  signals.  How 
the  assistant  glared  at  me  every  time  I 
changed  my  seat !  Finally  I  winked  at  him, 
and  walked  out  of  the  theatre.  He  gave  me 
a  grateful  look  as  I  past  out  of  the  door. 


WIRELESS  AT  THE  FRONT. 

Altho  very  little  has  been  permitted  to 
pass  the  censors,  it  is  understood  that  wire- 
less is  being  employed  to  an  unprecedented 
degree  on  the  battle  front  in  Italy.  In  the 
front  line  trenches  the  aerial  wires  are 
strung  along  a  parapet  just  behind  the  bar- 
ricade. In  the  support  trenches  the  aerial 
wires  are  elevated  a  few  feet  above  the 
ground,  while  far  to  the  rear  the  aerial  is 
generally  elevated  to  about  twenty  feet  by 
light  bamboo  poles.  The  sectional  masts 
familiar  to  our  Army  pack  sets  and  wagon 
sets  are  practically  unknown  in  the  war 
zone,  for  the  reason  that  a  modest  aerial 
a  few  feet  above  the  ground  is  sufficient 
for  the  short  ranges  which  must  be  covered. 
Wireless  telegraphy  is  a  necessity  in  com- 
munication work,  because  of  the  difficulty 
of  laying  telephone  and  telegraph  lines  and 
then  maintaining  them  across  shell-sprayed 
terrain. 


SOLDIERS  AND  SAILORS!!! 

Write  us  now  and  then  when  the  spirit 
moves  you.  A  few  words  from  you  telling 
of  life  "in  the  service"  may  be  the  means  of 
attracting  many  valuable  recruits. 


December,  1917 


THE  ELECTRICAL  EXPERIMENTER 


565 


LEARN  THE  CODE 

WITH  THE  OMNI  GRAPH 


The  Omnigraph  Automatic  Transmitter  will  teach  you  the  Continental  and  the  Morse  Codes,  at  home,  in  half  the  usual  time 
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The  Omnigraph,  connected  with  Buzzer  or  Sounder,  will  send  you  unlimited  Wireless  or  Morse  Code  messages,  by  the  hour 
and  at  any  speed  you  desire.  Invaluable  also  for  practice  with  the  Morse  Light,  allowing  you  to  quickly  master  the  Blinker 
system. 

We  offer  the  Omnigraph  as  a  positive  success  and  with  the  strongest  of  endorsements.    It  has  been  adopted  by  the  U.  S. 

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operators  applying  for  Radio  licenses.  Other  De- 
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up  your  Code  practice. 

Send  for  free  catalog  describing  3  differ- 
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How  did  you  learn  to  talk  ?    By  listening. 


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EVERYBODY  CAN  LEARN  TELEGRAPHY 
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THE  TELE-SET  B-l  is  a  marvelous,  loud  sounding,  handsome  electric  key  and 
sounder,  thoroughly  practical  tor  the  sending  and  reception  of  messages.  Its  click 
is  the  same  as  that  of  a  regulation  pattern  telegraph  instrument.  An  ideal  appa- 
ratus for  learning  the  telegraph  code. 

THE  PRICE  IS  AMAZINGLY  LOW 

but  don't  judge  the  Tele-Set  B-I  by  its  price.  Appreciating  the  present  great 

demand  for  a  good  learner's  set  we  determined  to  place  an  instrument  on  the 

market  at  a  price  within  the  reach  of  every  boy,  every  girl,  every  man  and  every 
woman  in  the  land. 


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Learn  Telegraphy— It  IsYour  Patriotic  Duty 

The  government  at  present  is  in  urgent  need  of  good  tele- 
graph operators.    Telegraphers  are  always  in  demand. 


THE  TELE-SET  B-l  is  identically  the  same  instrument  as  we  have  supplied  for 
years  in  our  famous  Telesot  outfits  of  which  thousands  have  heen  sold. 
The  Tele-Set  B-I  is  mounted  on  a  neat  wooden  base,  black  rubber  finish,  size 
2Vz  x  3VS  inches.  The  metal  frame  is  beautifully  nickeled  and  polished.  The  magnet 
winding  is  made  of  enameled  wire  and  adds  greatly  to  the  attractiveness.  Two 
binding  posts  are  furnished  on  the  instrument.  The  key  strap  is  of  nickeled  and 
polished  brass.  A  nickeled  adjusting  screw  with  lock  nut  regulates  the  height  of 
the  sound  lever.  The  finger  button  is  of  genuine  moulded  bard  rubber  composition. 
The  Tele-Set  operates  on  one  cell  dry  or  wet  cell  battery.  It  is  sturdy  and  will  not 
easily  get  out  of  order. 


TWO  BARGAINS 

No.  I     Relay  magnet  coils,  perfect 

condition.     Complete   with  core. 

Wound  with  No.  36  copper  wire. 

Value  of  wire  alone  is  20  cents. 

Worth    40c.      Our    special  price 

until  sold  3  for  25  cents 

Not    less   than   3   sold.  Shipping 

weight.  1  lb. 
No.  2    FIBRE — at  prices  below  cost 

of  manufacture. 

New  vulcanized  black  fibre,  high- 
est quality.  Two  sizes  only,  pol- 
ished edges.  Every  experimenter 
will  find  countless  uses  for  this 
splendid  fibre. 

Size    I — %    in.    Square,  per 
foot   $0.16 

Size  2 — 5/16  in.  x  1  in.,  per 

foot   17 

Shipping  weight  1   lb.  for  2  ft. 

Not  less  than  1  ft,  sold.     Cut  to 

any  length  up  to  3  ft. 


Never  befnfre  has  so  fine  an  instrument  been  sold  at  so  low  a  price.  Order  your 
Tele-Set  B-I  today.    It  will  come  to  you  by  return  mail. 

Tele-Set  B-l.  packed  in  neat  box,  complete  with  code  chart.    Prepaid  $0.50 

Tele-Set.  two  station  outfit,  packed  in  attractive  box,  with  two  instruments, 
code  chart.  S  ft.  insulated  wire  and  instructions.    Prepaid   1.00 


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566  THE  ELECTRICAL  EXPERIMENTER  December,  1917 


AMERICA  NEEDS 


(8* 


Submarines,  torpedoes,  flying  machines,  machine  guns,  immense 
howitzers,  the  British  "tanks,"  and  an  untold  number  of  other 
products  of  American  brains,  are  dominant  factors  in  the  Great 
War.  We  are  just  starting,  our — YOUR — ingenuity  must  lead  to  Victory. 
Uncle  Sam— the  whole  civilized  World — is  seeking  ideas  that  will  aid  in  the 
fight.  Can't  you  help  with  even  ONE  of  thousands  of  simple  things  that  will 
win  recognition — perhaps  fortune  for  you? 

The  need  is  for  inventions  of  peace,  too.  Never  before  was  there  such  a 
demand  for  new  ideas  of  all  kinds — never  before  have  so  many  manufacturers, 
and  other  patent  buyers,  written  me  for  good  things  protected  by  OWEN 
PATENTS.  There  is,  to-day,  a  market  for  thousands  of  ideas — including 
YOURS.  Write  for  my  free  booklet  and  see — read  for  yourself  the  hundreds 
of  requests  recently  received. 

You  incur  no  obligation  by  writing  me.  My  advice  costs  nothing  and  I 
make  no  charge  for  an  opinion  as  to  patentability  of  your  idea.  If  my 
opinion  is  favorable  I  will  back  it  up  by  a  Guarantee  Contract  which  protects 
you  fully.  If  you  want  to  sell  your  invention,  I  will  help  you,  and  will 
advertise  it,  free  of  charge,  in  "INVENTION  AND  MANUFACTURING." 

A  simple  request  will  bring  to  you  at  once,  my  four  free  books: — "SUC- 
CESSFUL PATENTS,"  a  72  page  guide  telling  how  to  proceed,  gives  refer- 
ences, etc.;  "STEPPING  STONES  '  tells  the  truth  about  prizes  for  inven- 
tions, gives  hundreds  of  hints  of  inventions  wanted,  etc.;  "PATENT 
BUYERS"  publishes  over  400  requests  of  manufacturers  and  others  who 
want  OWEN  PATENTS,  together  with  ideas  they  want;  "PATENT  PRO- 
MOTION," tells  you  how  to  sell,  why  some  inventors  fail,  discusses  the 
value  of  your  idea,  etc. 

Write  for  these  books  to-day.  I  will  send  you  a  signed  agreement  that 
will  protect  you  before  you  disclose  your  invention. 


RICHARD  B  OWN  Pal  eni  Lauiyer 

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without  cost.  Our  new  book  is 
Free.  Send  model  or  sketch  for 
free  opinion. 

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Electricians 


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ING !  Save  Tltot,  MONfcY. 
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Drawings,  containing  all  the 
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and  connection  up-to-the-minute  as  used  by  first  class  electricians  for 
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and  Electric  Gas  Lighting.  These  drawings  are  bound.in  the  form  of 
a  flexible  book  (9x121  for  convenience  in  using  on  the  job.  faend  lot 
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ATTORNEYS 


Inventions  TV&.nied 

More  than  $25,000,000  worth  of  toys  are  used  annually  to  the  Dnlted 
States.  Some  of  the  most  simple  toys  have  netted  fortunes  to  the 
inventors.  We  have  requests  from  many  of  the  largest  toy  makers  in 
the  United  States  for  patents  on  toys  and  novelties  obtained  through 
us.  Work  up  some  toy  or  game  that  is  amusing,  educational,  that 
promotes  health  by  exercise  or  stimulates  interest  to  engineering, 
chemistry,  electricity,  and  submit  it  to  us  for  our  free  opinion  and 
report.  If  it  is  new  and  patentable  we  will  aid  you  to  obtaining 
protection  on  it  and  in  closing  negotiations  with  manufacturers. 
For  instance,  on  June  10.  1916.  we  filed  an  application  for  patent  on 
a  sand  operated  toy  shown  below,  invented  by  our  client.  Mr,  B. 
Bliss,  of  Holt.  Mich.,  and  on  June  21,  1916.  put  him  to  touch  with 
the  largest  toy  manufacturers  in  the  U.  S.  On  December  26,  1916. 
the  patent  was  allowed  and  before  the  patent  issued  we  had  closed 
negotiations  for  Mr.  Bliss,  selling  the  invention  to  the  largest  sand 
toy  manufacturer  in  the  U.  S. 

No  matter  what  your  invention  may  be  our  cooperation  is.  First,  to 
help  you  establish  your  rights  before  sending  a  sketch,  drawing  or 
model  to  any  attorney;  Second,  to  give  a  frank  opinion  whether  it  will 
pay  to  patent  your  idea,  based  upon  our  extensive  knowledge  of  the 
patent  laws,  manufacturers'  wants  and  facilities;  Third,  to  obtain  for 
you  on  reasonable  terms,  a  patent  that  absolutely  protects;  and. 
Fourth,  advise  and  assist  you  to  making  the  invention  a  source  of 
profit  by  outright  sale,  territorial  grants,  obtaining  royalty  or 
the  independent  manufacture  of  the  invention. 
Send  drawing  or  model  for  opinion.    You  can  get  our 
book  on  patents,  form   "Evidence  of  Conception"  and 
bulletins  of  inventions  wanted,  free  of  charge,  by  asking 
for  them  on  a  post  card,  or  simplv  mail  coupon  below. 


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Send  me  free  book,  "Inventions-Patenting  and  Promoting,"  spe- 
cial bulletins  of  Inventions  Wanted,  and  blank  form  "Evidence  of 
Conception." 

Name   

Address   


Edited  by 

In  this  Department  we  publish  such  matter  as 
those  who  are  in  doubt  as  to  certain  Patent 
Advice"  cannot  be  answered  by  mail  free  of 
benefit  of  all  readers.  If  the  idea  is  thought  to 
divulge  details,  in  order  to  protect  the  inventor 

Should  advice  be  desired  by  mail  a  nominal 
Sketches  and  descriptions  must  be  clear  and  ex 
ten  on. 


NECK-TIE. 

(181.)  Carleton  A.  Howiler,  Akron,  O., 
submits  an  illustration  and  description  of  a 
four-in-hand  tie  which  does  not  need  to  be 
tied  by  hand.  It  contains  a  certain  device 
whereby  it  is  possible  to  put  it  in  place  very 
quickly  thereby  constituting  a  considerable 
saving  of  time. 

A.  The  idea  is  quite  good  and  as  original 
as  it  is  probably  new.  The  point  however 
is :  how  many  men  would  wish  to  wear  a 
tie  of  this  kind?  Still  we  do  not  wish  to 
condemn  the  idea  on  account  of  this,  as 
there  are  certainly  a  great  many  men  who 
would  gladly  buy  such  a  tie.  We  think 
patent  protection  can  be  had  on  this  device, 
but  as  a  precautionary  measure,  would  ad- 
vise our  correspondent  to  get  in  touch  with 
a  patent  attorney  first. 


ELECTRIC  WIND  SHIELD. 

(182.)  Norman  J.  Shoffer,  Norwich, 
Conn.,  has  devised  a  wind  shield  for  auto- 
mobiles which  is  heated  in  a  certain  man- 
ner by  electrical  means,  the  idea  being  to 
heat  the  wind  shield  in  order  to  keep  the 
glass  warm  thus  melting  the  snow ;  it  will 
also  turn  the  rain  into  steam. 

A.  This  is  a  very  good  idea,  and  seems  to 
us  rather  practical  if  certain  means  could 
be  incorporated  in  the  device,  which  we 
shall  be  glad  to  give  our  correspondent  if 
he  desires  them. 

As  sent  in  to  us  in  its  original  form  the 
device  is  not  entirely  "fool-proof." 


ELECTRICAL  MINE. 

(183.)  Paul  Brooks,  Milton,  Pa.,  has 
submitted  to  us  an  idea  of  a  wirelessly 
controlled  land  mine  to  be  planted  by  troops 
and  which  mine  is  to  be  used  only  when 
the  troops  are  forced  to  retreat.  In  that 
case  the  mines  will  be  exploded  under  the 
enemy  thereby  impeding  his  progress.  A 
clever  tuning  device  has  been  included  in 
this  invention. 

A.  This  is  a  good  idea,  and  inasmuch  as 
our  correspondent  also  took  care  to  safe- 
guard the  mine  so  that  it  could  not  be 
blown  up  accidently,  we  think  that  it  might 
possibly  be  adopted  by  some  of  the  warring 
nations.  A  device  of  this  kind  could  be 
used  as  a  trap  by  ordering  the  troops  to 
make  a  feint  retreat,  thereby  annihilating 
the  advancing  enemy's  troops,  after  which 
the  land  could  be  occupied  again  by  the 
original  forces.  We  advise  to  have  patent 
attorney  look  into  the  patent  question,  as 
we  are  not  quite  certain  that  this  particular' 
invention  does  not  infringe  with  a  similar 
one  that  came  to  our  notice  not  long  ago. 


MAIL  TIME  SAVER. 

(184.)  Rudolph  Goldstone,  Connellsville, 
Pa.,  submits  an  idea  of  an  electrical  device 
to  be  incorporated  in  a  rural  mail  box,  the 
idea  being  that  as  soon  as  the  letter  is  de- 
posited, a  bell  will  ring  in  the  distant  house 
thereby  announcing  that  mail  is  in  the  box. 

A.  While  this  is  not  a  new  idea,  and 
while  a  great  many  patents  had  been  taken 


You  beneft  by  mentioning  "The  Electrical  Experimenter"  when  writing  to  advertisers. 


December,  1917 


THE  ELECTRICAL  EXPERIMENTER 


567 


H.  GERNSBACK. 

is  of  interest  to  inventors  and  particularly  to 
Phases.  Regular  inquiries  addrest  to  "Patent 
charge.  Such  inquiries  are  publisht  here  for  the 
be  of  importance,  we  make  it  a  rule  not  to 
as  far  as  it  is  possible  to  do  so. 
charge  of  $1.00  is  made  for  each  question, 
plicit.     Only  one  side  of  sheet  should  be  writ- 


out  on  similar  devices,  we  think  the  one 
submitted  to  us  has  some  possibilities,  but 
before  applying  for  a  patent,  we  would  ad- 
vise our  correspondent  to  have  a  search 
made  in  the  patent  office  for  patentability. 


HEAT  CONTROLLED  FAN. 

(185.)  Francis  Ziesse,  Brooklyn,  N.  Y., 
has  submitted  to  us  description  and  illus- 
tration of  a  highly  ingenious  electric  fan 
attachment,  the  idea  being  that  by  means  of 
a  certain  adjustment  the  fan  will  start  re- 
volving as  soon  as  the  temperature  reaches 
a  certain  point.  In  other  words,  on  a  very 
hot  day  when  you  are  too  busy  to  pay  at- 
tention to  the  heat,  the  fan  will  not  forget 
about  it,  but  will  start  revolving  on  its  own 
accord  when  the  room  becomes  hot  enough. 

A.  This  certainly  is  a  capital  idea  and 
while  the  device  as  submitted  by  our  corre- 
spondent is  good,  it  is  perhaps  not  quite  as 
practical  as  it  might  be.  We  think  that  if 
some  of  the  features  are  modified,  a  com- 
mercial proposition  can  be  readily  obtained. 
We  think  a  device  of  this  kind  is  patentable. 


OSCILLATION  TRANSFORMER. 

(186.)  M.  Kent  Steddom,  Oklahoma 
City,  Okla.,  submits  to  us  what  he  calls  a 
"rotating  oscillation  transformer."  The 
idea  is  that  combining  a  rotary  spark  gap 
with  an  oscillation  transformer  in  a  certain 
manner. 

A.  This  is  certainly  a  very  fine  as  well  as 
clever  idea  and  we  heartily  approve  of  it 
as  it  combines  two  instruments  into  one. 
The  disposition  as  well  as  the  arrangement 
is  indeed  very  ingenious  and  we  think  there 
is  no  doubt  but  that  good  patent  protection 
can  be  had  upon  a  device  of  this  kind.  We 
have  never  come  across  anything  quite  the 
same,  and  our  advice  to  our  correspondent 
is  to  get  in  touch  with  a  patent  attorney 
at  once. 


SOCKET  TRANSFORMER. 

(187)  J.  B.  Thompson  of  Paragould, 
Ark.,  submits  a  lamp  socket  transformer 
of  minute  design,  which  is  supposed  to  be 
screwed  into  an  ordinary  lamp  socket  and 
can  be  used  for  running  lamps,  toys,  etc. 

A.  There  is  nothing  unusual  in  the  idea. 
As  a  matter  of  fact,  a  great  many  trans- 
formers of  this  kind  are  on  the  market 
at  present,  several  types  being  made  by  the 
General  Electric  Co. 


CINEMATOGRAPHIC  DEVICE. 

(188)  Henry  Gruen,  New  York  City, 
claims  to  have  invented  a  scouting  camera 
for  the  purpose  of  taking  cinematographic 
records  of  the  entire  surrounding  country 
or  a  battlefield,  thus  substituting  an  aero- 
plane and  eliminating  dangers  for  aviators. 
Use  is  made  of  a  miniature  balloon  of  the 
Zeppelin  type,  the  apparatus  to  work  by 
means  of  electricity  from  the  ground.  Our 
correspondent  asks  if  an  invention  of  this 
kind  has  any  possibilities,  and  if  it  is 
patentable,  etc. 

(Continued  on  next  page) 


/ 
/ 

/ 

| 


patent 
"irm 
in  The 
Wor*ld 


Before  send- 
ing your  in 
vention  to  any 
attorney  or  mariu 
facturer  or  disclosing 
your   invention,  write 
for  our  free  blank  form 

PROOF  OF  CONCEPTION  in  order  to  protect  your 
invention  and  secure  your  rights.  This  should  be  signed 
and  witnessed  and  returned  to  us,  together  with  a  model 
or  sketch  and  description  of  your  invention,  and  we  will 
give  a  FREE  OPINION  as  to  the  patentability  of  the 
invention.  If  we  report  the  invention  patentable  we 
will  furnish  a  Certificate  of  Patentability. 

This  certificate  of  Patentability,  together  with  our 
blank  form  Proof  of  Conception/will  protect  the  in- 
ventor and  serve  as  proof  "of  the'invention  until  the 
case  can  be  filed  in  the  U.,S.!  Patent  Off  ice. 

OBTAINING  ASSISTANCE  FOR  INVEN- 
TORS— Our  certificate  is  of  great  assistance  to 
inventors  who  require  financial  aid  to  obtain 
patents. 

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issued  for  free  distribution. 

HOW  iTO  [OBTAIN  T  A  'PATENT 

Our  illustrated  eighty-page  Guide 
Book  is  a  Book  of  reference  for  in- 
ventors and  contains  100  mechanical 
movements,  illustrated  and  de- 
scribed. Tells  how  to  invent  for 
profit. 


WHAT  TO  INVENT 

Contains  a  valuable  list  of  inven- 
tions wanted  and  suggestions  con- 
cerning profitable  fields  of  inven- 
tions ;  also  information  regarding 
prizes  offered  for  inventions 
amounting  to  ONE  MILLION 
DOLLARS. 


LIST  OF  PATENT  BUYERS 

Contains  requests  from  manufacturers,  mail  order  houses  and  promoters 
for  patents  secured  by  us  and  suggestions  as  to  New  Ideas  they  wish  to 
purchase.  We  place  our  clients  in  touch  with  capital  free  of  charge.  We 
have  recently  received  over  300  requests  from  manufacturers. 

MILLIONS  IN  TRADE-MARKS 

Shows  the  value  of  Trade-Marks  and  in- 
formation regarding  unfair  competition. 
We  advertise  Our  Clients'  Inventions  Free  in  a 

list  of  Sunday  newspapers,  in  manufacturers' 
journals  and  in  World's  Progress.  Sample  Copy 
Free.  We  save  you  time  and  money  in  securing 
patents.  After  the  patent  is  granted  we  assist  you 
to  sell  your  patent. 

WANTED  NEW  IDEAS 


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PATENT  ATTORNEYS 

New  York  Offices: 
1001   to  1007  Woolworth  Bldg. 

Philadelphia  Offices: 
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Main  Offices:  779  Ninth  Street,  N.  W.,  Washington,  i'lCC. 

Name.  Address.  .  


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568 


THE  ELECTRICAL  EXPERIMENTER 


December,  1917 


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free  pocket  mapsIaddress../.     


A.  Nothing  new  is  contained  in  this 
idea,  schemes  of  this  nature  having  been 
in  use  by  the  Allies  as  well  as  by  the 
Central  Powers,  and  sometimes  quite  good 
pictures  have  been  obtained.  More  times, 
however,  the  balloons  with  the  camera  have 
been  shot  down  by  enemy  fire. 


SAFETY  COAT  HANGER. 

(189)  John  F.  Bingham  of  West 
Toronto,  Can.,  has  submitted  an  idea  for 
an  automatic  coat  and  umbrella  hanger, 
making  it  impossible  for  an  unauthorized 
person  to  take  either  coat  or  umbrella,  the 
idea  of  the  device  being  that  a  coin,  say 
for  instance,  one-cent  or  five-cent  piece  is 
dropt  thru  a  slot  which  delivers  a  key  to 
the  patron.  Then  the  coat  as  well  as  the 
umbrella  is  hung  up  on  the  device  which 
automatically  closes,  and  the  wearing  ap- 
parel can  then  not  be  taken  from  the 
device  unless  a  key  opens  the  lock. 

A.  This  is  a  really  excellent  idea,  the 
best  part  being  that  it  is  simple  and  should 
be  rather  cheap  to  manufacture.  This  is 
an  important  consideration,  as  for  instance, 
restaurant  proprietors  would  not  wish  to 
invest  a  heavy  sum  for  a  device  of  this 
kind.  To  our  mind  the  invention  looks 
original,  and  we  think  that  little  trouble 
will  be  had  in  securing  a  patent.  Our  rec- 
ords do  not  show  that  anything  like  it  has 
been  patented  in  the  past. 


SOME  DISCOVERIES  NOT  MADE  BY 
TEUTONS 

{Continued  from  page  563) 
pedo,  shrapnel,  automatic  cannon,  maga- 
zine rifle,  breech-loading  gun.  Gatling  gun, 
revolver,  Maxim  silencer,  hammerless  gun, 
gunboat,  ironclad  batteries  or  ship  armor 
plate,  revolving  turret,  submarine  or  air- 
plane. 

Germany  did  not  produce  the  first  ani- 
line dye,  vulcanized  rubber,  liquid  gas,  gas 
engine,  water  gas,  thermometer,  barometer, 
piano  forte,  barbed  wire,  cut  nails,  plate 
glass,  circular  saw,  cable  car,  electric  car, 
sleeping  car,  air  brake,  bicycle,  automobile, 
pneumatic  tire,  sewing  machine,  typewriter, 
calculating  machine,  cash  register,  steel 
writing  pen,  etc.,  ad  infinitum. 

The  greatest  thing  that  Germany  has 
done,  however,  is  to  falsely  advertise  her- 
self as  the  light  of  the  world.  No  son 
of  hers  invented  the  electric  light,  the 
gas  light,  the  acetlyene  light,  the  kerosene 
light,  the  searchlight,  the  flashlight,  the 
safety  lamp,  the  candle  dip  or  the  friction 
match.  America,  France,  England  and 
other  "untutored"  and  "unkultured"  (sic) 
nations  performed  these  tasks.  The  sun, 
moon  and  stars  are  the  only  lights  left  for 
Germany's  contention,  and  according  to  the 
Mosaic  account,  the  Lord  and  not  the 
Kaiser,  made  and  placed  them  in  the  firma- 
ment. 

Daguerre,  a  Frenchman,  presented  us 
with  photography.  Our  own  Edison 
brought  forth  the  motion  picture  to  de- 
light and  instruct  the  eye  and  the  phono- 
graph to  please  and  teach  the  ear.  Galileo, 
who  first  saw  the  heavens  with  a  tele- 
scope, was  an  Italian.  The  men  who  first 
saw  the  earth  and  its  teeming  life  with  a 
microscope  were  not  of  German  origin. 
By  use  of  the  compound  microscope,  Pas- 
teur, the  French  biologist,  as  early  as  1857 
demonstrated  a  connection  between  the 
microscopic  organisms  and  disease.  This 
was  nine  years  before  Dr.  Kock,  the  Ger- 
man bacteriologist  had  graduated.  In  this 
connection  the  important  antiseptic  surgery 
of  Dr.  Lister,  of  England,  should  be  rec- 
orded.   Edward  Jenner,  the  discoverer  of 


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December,  1917 


THE  ELECTRICAL  EXPERIMENTER 


569 


vaccination,  and  Harvey,  the  discoverer  of 
the  circulation  of  the  blood,  were  English- 
men. An  American  taught  the  world  the 
use  of  anesthetics.  Our  dentists  excel  all 
others.  They  are  employed  by  many 
crowned  heads— even  the  Kaiser  has  his. 

The  Teutons  have  not  shown  the  engi- 
neering skill  of  the  French,  who  cut  the 
Suez  Canal,  or  of  the  American  who  joined 
the  Atlantic  and  the  Pacific  at  Panama. 
The  decimal  or  metric  system  by  which 
the  Germans  make  their  measurements  is 
a  gift  from  France.  The  method  by  which 
they  make  their  steel  is  that  of  Sir  Henry 
Bessemer,  of  England.  Many  of  the  fruits 
and  vegetables  of  which  they  eat  an  enor- 
mous quantity  were  brought  forth  by  our 
own  peerless  Burbank. 

Lavoisier,  the  father  of  modern  chem- 
istry, was  French.  Linnaeus,  the  founder 
of  botany,  was  of  Swedish  origin.  To 
Hutton,  of  England,  we  are  indebted  for 
geology;  to  Mary,  of  Virginia,  for  the 
physiography  of  the  sea;  to  Descartes,  of 
French  parentage,  for  analytical  geometry ; 
to  Comte,  of  France,  for  sociology;  to 
Germany  for  sauerkraut  and  pretzels.  Her 
sons  did  not  compose  the  crew  of  Magel- 
lan's fleet,  the  first  to  circumnavigate  the 
globe.  A  German  did  not  discover  the 
North  Pole  nor  lead  the  way  toward  the 
South  Pole. 


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Wiring  for  Light  and  Power.  By  Terrell 
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The  Mechanical  World.  Electrical  Pocket 
Book  for  1917.  Cloth  bound,  304  pages; 
size  A1/a  x  6%  inches,  illustrated,  price  45 
cents  postpaid.  Publisht  by  Emmott  & 
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Circuits  and  Materials,  Hysteresis,  Eddy  Currents, 
Direct  and  Alternating  Current  Motors,  Generators, 
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various  circuits  and  apparatus  and  the  instruments 
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on  Electrical  Measurements  and  Testing.  This 
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is  presented  in  a  compact  form  on  Transmission  Line 
Calculation.  In  the  section  devoted  to  Electrical 
Meters,  a  note  on  Mercury  Meters  has  been  intro- 
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Switching  has  been  greatly  revised. 

A  goodly  number  of  pages  have  been  devoted  to 
useful  tables  and  gages;  also  charts  on  square  and 
cubic  roots,  Logarithms  and  Anti-logarithms.  A 
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The  authors  shall  be  very  pleased  to  consider 
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While  the  book  has  evidently  been  prepared  for 

{Continued  on  page  573) 


PATENTS 

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5  70 


THE  ELECTRICAL  EXPERIMENTER 


December,  1917 


EXPERIMENTERS! 

Student's  Chromic  Plunge  Battery 

HERE  is  a  little  battery  that  will  be  highly  welcomed  by  every  experimenter  all 
over  the  country.  It  is  the  first  low  priced,  as  well  as  fool-proof  chromic  acid 
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Now,  we  do  not  wish  to  mislead  you,  so  we'll  tell  you  at  the  start  what  this  battery 
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coupons  for  your  166  page  Free  Wireless  Course  In  20 


NAME 


ADDRESS   

STATE  E.B.12. 


CHEMICAL 
EXPERIMENTERS 

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December,  1917 


THE  ELECTRICAL  EXPERIMENTER 


571 


RADIO  ROLL  OF  HONOR. 

(Continued  from  page  533) 


Tennessee 

Greer  W.  Peck 
Texas 

Chas.  A.  Fielder 
A.  G.  Stout 
Lyle  Jones 
I.  M.  Laybowm 
Archibold  Wellborn 

Utah 

L.  B.  Rosa 

Virginia 

Leo  E.  Simonton 

Robt.  A.  Harrison,  Jr. 

Bernard  Green 

F.  W.  &  S.  M.  Craigie 

C.  D.  Blair 

A.  G.  Connell 

Washington 

J.  Kornegay 

J.  Oliver  Dawson 


N 


E.  Fraser 
F.  Bender 
Ray  R.  Ames 
Walter  Buege 


West  Virginia 

E.  K.  Wills 

Wisconsin 

Edw.  Matt 

Pierce  J.  Van  Alstyne 
Wm.  E.  Erickson 
Earl  Fischer 
George  Koresh 
O.  A.  Lamoreux 
Melvin  Becker 
Lloyd  Scholl 

F.  H.  Cirves 

J.  Donald  Vandercook 
Herbert  Zetterlund 

Wyoming 

Gilbert  Hill 

Dr.  L.  G.  Van  Slyke 

Porto  Rico 
Joaquin  M.  Mayoral 


showing  the  volume  of  each  liquid. 

Into  a  clean,  small  beaker  draw  off  10 
cc.  of  NaOH  solution.  To  this  add  a  drop 
of  phenolphthaleln  solution  or  a  few  drops 
of  litmus  solution.  Now  move  the  beaker 
under  the  acid  burette  and  slowly  draw 
into  it  enough  acid  to  exactly  neutralize 
the  alkali.  The  last  portions  must  be  let 
in  drop  by  drop,  with  constant  stirring. 
Neutralization  is  determined  by  the  disap- 
pearance of  color  of  the  indicator,  or  the 
pink  tinge  in  case  litmus  is  used.  At  that 
instant  stop  the  flow  of  acid. 

Read  the  volume  of  NaOH  solution  and 
also  of  the  HC1.    Record  as  follows : — 


Volume  HC1  (first) 

Ratio  of 
NaOH  Sol. 

to  HC1  

Volume  HC1  (last) 

Ratio  1  c.c. 
NaOH  to 
HC1.... 

Volume  HC1  (used) 


Volume  NaOH  Sol. 
(first)   .  . .  .c.c. 


Volume  NaOH  Sol. 
(last)  .  . .  .c.c. 


Volume  NaOH  Sol. 
(used)  .  . .  .c.c. 


RADIO  ROLL  OF  HONOR 

Application  for  Membership  in  the 
Radio  League  of  America 

THE  UNDERSIGNED,  a  Radio  Amateur,  am  the  owner  of  a  Wireless 
Station  described  in  full  in  this  application.    My  station  has  been  in  use 

since   and  I  herewith  desire  to 

apply  for  membership  in  the  RADIO  LEAGUE  OF  AMERICA.  I  will  abide 
by  all  the  rules  of  the  LEAGUE,  and  I  particularly  pledge  my  services  as  a 
Radio  operator,  or  for  Signal  Corps  duty  to  the  United  States  Government 
when  called  upon. 

I  understand  that  this  blank  with  my  signature  will  be  sent  to  the  United 
States  Government  officials  at  Washington,  who  will  make  a  record  of  my  name. 

Witnesses  to  signature:  Name  

  City  

State  

  Date  191 


Description  of  My  Station  and  Apparatus 

Sending   


Receiving 


I  can  send  approximately  words  per  minute. 

1  can  receive  approximately  words  per  minute. 

My  age  is  years. 


(12-17) 


EXPERIMENTAL  CHEMISTRY. 

(Continued  from  page  559) 
in  100  cc.  of  water.    Draw  off  a  few  drops 
of  liquid  from  each  burette,  to  get  rid  of 
the  air  at  the  end. 

Take  accurate  readings  of  each  burette, 
(reading  from  the  bottom  of  the  meniscus, 
see  Fig.  95),  and  make  records. 

NaOH   c.c. 

HC1   c.c. 


The  experiment  might  be  extended  by 
evaporating  the  solution  and  weighing  the 
solid  NaCl  and  computing  the  weight  of 
the  NaCl  per  1  cc.  of  HC1  or  NaOH  solu- 
tion used. 

EXPERIMENT  110.  (Quantitative.) 

Do  this  experiment  exactly  in  the  same 
way  as  the  previous  one,  except  first  to 
(Continued  on  page  577) 


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American  electric  apparatus  is  gaining 
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to  North  America  and  practically  $1,000,000 
to  Europe,  the  total  telephones  being  ex- 
ported in  1917  being  twice  as  great  in  value 
as  in  1912.  Of  the  nearly  $500,000  worth 
of  electric  fans  exported  in  1917,  the  largest 
market  was  in  India,  Hong  Kong,  the 
Straits  Settlements,  China,  Japan  and  Siam 
got  big  shipments. 


LOCATING  THE  SUBMARINE  BY 
RADIO. 

(Continued  from  page  510) 

it  will  be  heard  in  the  telephone  receivers 
as  a  distinct  sound. 

In  other  words,  the  beat  frequency  note 
giving  an  audible  signal  is  the  difference 


Circuits  Used  in  Radio  Submarine  Detector, 
as  Devised  by  Mr.  Bishop. 


between  the  changed  radio  frequency  oscil- 
lations in  circuit  (1)  and  those  produced 
in  the  free  oscillator  circuit  No.  2,  which 
latter  is  non-radiative,  as  becomes  evident. 

In  practise  the  different  sets  of  apparatus 
are  mounted  in  their  respective  cabinets 
and  the  cabinets  moved  about  on  the  in- 
strument table  -until  the  proper  and  most 
desirable  inductive  relation  between  them 
is  obtained. 


HOW  I  TELEGRAPH  PICTURES. 

(Continued,  from  page  517) 

24,000  revolutions  per  minute.  This  is  the|^ 
mechanical  difficulty  of  tele-vision.  As  to 
the  electrical  difficulty,  it  will  suffice  to 
say  that  a  picture  requires  several  thousand 
variations  of  light  and  shade,  and  at  the 
present  stage  of  electrical  development  five 
hundred  breaks  per  second  cannot  be  ex- 
ceeded over  a  long  line.  Animated  car- 
toons should  offer  no  great  obstacle,  but 
the  problem  of  tele-vision  is  to  render  an 
object  visible  at  a  distance.  Several  wires, 
of  course,  make  tele-vision  possible,  but  a 
practical,  one-circuit  apparatus  would  seem 
to  await  a  more  complete  knowledge  of 
electricity  or  of  the  ether.  Tele-vision  for 
short  distances  may  be  accomplished  with 
lenses,  mirrors  and  the  prism,  but  the  im- 
pressions soon  become  indistinct. 

The  telegraphing  of  pictures  is  a  more 
fruitful  field,  and  as  yet  it  is  a  compara- 
tively undeveloped  art,  affording  great  op- 
portunity to  the  electrical  experimenter. 


THE  MARVELS  OF  RADIO- 
ACTIVITY. 

(Continued  from  page  515) 
latter  from  Colorado  and  Utah.  Radium 
must  be  regarded  as  a  changing  element, 
its  calculated  period  being  several  thousand 
years.  Hence,  in  order  that  any  radium 
exist  in  the  geologically  old  minerals,  the 
supply  must  be  kept  up  by  the  transforma- 
tion of  some  other  substance.  Since  radium 
is  always  found  in  uranium  minerals,  it  is 
plausible  that  uranium  is  the  parent  element 
for  the  derivation  of  radium.  If  this  is  the 
case  in  old  minerals  which  are  unchanged 
by  the  action  of  underground  waters,  the 
ratio  of  radium  to  uranium  must  be  con- 
stant. This  has  been  shown  by  several 
investigators  to  be  true,  the  quantity  of 
radium  being  determined  by  the  emanation 
method  previously  described  and  the  ura- 
nium by  chemical  analysis. 

It  is  necessary  to  show,  in  proving  the 
relation  of  radium  to  uranium,  that  radium 
appears  after  some  time  in  a  uranium 
compound  previously  purified.  The  first  at- 
tempts at  this  were  unsuccessful,  using 
periods  of  a  year.  It  was  then  decided  that 
some  intermediate  product  was  formed  be- 
tween uranium  and  radium.  This  was 
demonstrated  by  Soddy,  who  proved  that 
radium  does  appear  in  the  uranium  solution 
after  several  years  in  such  quantities  as  to 
indicate  another  slow-period  product  as 
intermediary. 

Actinium  preparations  were  also  found  to 
give  rise  to  a  growth  of  radium,  but  later 
researches  showed  that  the  radium  was  not 
due  to  the  actinium  itself  but  to  an  as- 
sociated substance,  separated  by  Boltwood, 
and  called  "Ionium."  From  its  calculated 
period  the  amount  of  ionium  in  uranium 
minerals  must  not  be  less  than  ten  times 
that  of  radium,  as  the  amount  decaying 
into  radium  is  one-tenth  of  its  amount  to 
supply  the  necessary  radium.  It  has  not  yet 
been  shown  that  uranium  produces  ionium, 
the  parent  element  of  radium,  but  there  is 
no  doubt  that  it  does  do  so. 

The  constant  relation  between  uranium 
and  radium  will  hold  only  for  minerals 
where  there  has  been  no  opportunity  for 
chemical  alteration  or  removal  of  any  part 
thru  the  action  of  underground  waters,  or 
other  agencies. 

End  Products  of  Change 
When  the  radio-active  changes  have  come 
to  the  end,  each  of  the  elements  uranium, 
thorium,  and  actinium  should  have  a  final 
product  with  a  very  slow  period  of  trans- 
formation, either  a  known  or  unknown  ele- 
ment. Since  an  alpha  particle's  expulsion 
lowers  the  atomic  weight  four  units — the 
atomic  weight  of  helium — the  atomic 
weights  of  the  end  products  now  known  can 
be  calculated.  For  example,  uranium  gives 
off  two  alpha  particles,  so  the  atomic  weight 
of  ionium  is  238.5—8  or  230.5.  Radium 
comes  out  226.5,  in  good  accordance  with 
experimental  values.  Similarly  polonium  is 
210.5,  and  the  final  product  206.5.  _  This 
value  is  very  close  to  the  atomic  weight  of 
lead,  and  so  indicates  this  is  the  final  product 
from  uranium  and  radium. 

Since  in  old  minerals  the  transformations 
have  taken  place  for  long  periods  of  time, 
the  radio-active  material  should  be  accom- 
panied by  the  end  product,  if  a  stable  ele- 
ment, in  considerable  quantities.  Boltwood 
has  shown  that  lead  invariably  occurs  in 
radio-active  minerals,  and  often  in  the 
amount  calculated  from  the  uranium  con- 
tent and  its  age.  This  problem  cannot  be 
definitely  settled  until  it  is  shown  ex- 
perimentally that  radium  changes  into  lead, 
or  better  that  polonium  breaks  up  into 
helium  and  lead.  An  extremely  large  amount 
of  polonium  would  be  necessary  for  this, 
but  several  have  shown  that  one  of  the 
products  of  polonium  is  helium. 

(Continued  on  page  578) 


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December,  1917 


THE  ELECTRICAL  EXPERIMENTER 


573 


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BOOK  REVIEW. 

(Continued  from  page  569) 

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stage  to  the  last  so  far  as  it  goes,  and  besides 
having  a  paragraph  on  how  to  study  and  concen- 
trate, it  also  contains  useful  tables  pertaining  to 
interest,  weights  and  measures,  etc. 

The  principal  aim  has  been  to  show  practical 
applications  of  theory  discust,  and  it  should  be  in 
every  real  student's  library,  whether  as  a  study 
or  reference  book.  The  treatment  is  such  that 
one  does  not  lose  interest  in  reading  the  various 
chapters,  as  the  author  has  happily_  combined  the 
charm  of  applied  mathematics  with  theoretical 
deductions. 


Electric  and  Magnetic  Measurements. 
By  Charles  M.  Smith,  Cloth  Bound;  373 
pages ;  5  x  8  inches ;  illustrated ;  price 
$2.40.  The  Macmillan  Co.,  New  York, 
N.  Y,  1917. 

A  valuable  book  to  all  persons  interested  in 
electrical  work;  especially  to  students  and  engineers. 
The  various  phases  of  electrical  measurements  are 
treated  on  very  thoroly  and  the  author  has  suc- 
ceeded in  bringing  out  many  technical  points  in 
a  popular  way,  which  should  appeal  particularly  to 
students  of  the  subject. 

The  book  has  been  developed  from  a  course  of 
lectures  and  laboratory  notes  which  have  been  used 
by  students  for  a  number  of  years.  In  presenting 
the  work,  it  is  pre-supposed  by  the  author  that  the 
reader  has  a  general  knowledge  of  physics  and 
calculus.  Much  of  the  material  has  been  gleaned 
from  standard  work,  and  the  laboratory  exercises 
are  described  in  such  a  way  that  particular  types 
of  apparatus  are  not  demanded,  unless  well-known 
and  generally  available. 

The  various  terms  are  simply  defined  and  every- 
thing is  so  arranged  that  the  student  is  taken  step 
by  step  thru  the  various  laboratory  experiments, 
in  easy  interesting  stages. 

The  work  is  liberally  illustrated  with  standard 
diagrams  of  commercial  measurements.  The  book 
is  unhesitatingly  recommended  to  all  students  of 
measuring  problems  and  the  general  treatment  of 
the  work  is  such  that  all  will  be  able  to  grasp  the 
explanations  readily. 


A  Treatise  On  Electricity.  By  F.  B. 
Pidduck ;  Cloth  Bound ;  640  pages ;  6  x 
9  inches ;  Cambridge  University  Press, 
England ;  G.  P.  Putnam's  Sons,  New 
York  City,  American  Representatives. 
Price  $3.60. 

The  author  in  this  rather  advanced  work  has 
covered  a  field  highly  above  the  average  reader 
and  it  is  to  students  of  universities,  engineers, 
etcetera,  that  this  work  will  really  appeal. 

The  general  principle  has  been  to  cover  in  one 
volume  the  theoretical  and  practical  side  of  elec- 
tricity; much  space  has  been  saved  by  omitting 
detailed  treatment  of  elementary  topics.  Starting 
from  the  beginning,  the  reader  attains  the  real 
gist  of  things,  but  he  must  be  a  good  mathemati- 
cian. 

The  following  are  some  of  the  interesting 
chapters:  Mathematics,  Permanent  Magnetism, 
Electrostatics,  Electric  currents  and  magnetic  ef- 
fects of  the  same,  Magnetism,  Induction,  Electro- 
lysis,  Electric   Oscillations,   Conduction   of  Elec- 


tricity thru  Gases,  Radio-activity,  and  the  theory 
of  Electrons.  Calculations,  Curve  plotting,  stand- 
ard measurements  and  other  similar  topics  are  only 
a  few  of  the  advanced  subjects  treated. 

The  author  has  dealt  in  an  interesting  way  with 
a  very  dry  subject  from  the  layman's  point  of 
view,  and  deserves  considerable  credit  for  the 
excellent  manner  in  which  the  whole  work  is 
covered. 

The  chapters  on  "Radio-activity"  and  "Conduc- 
tion of  Electricity  thru  Gases"  are  aspecially  in- 
teresting, many  important  developments  of  Radium 
being  brought  out.  In  summing  up  be  it  said  that 
it  is  a  very  worthy  volume,  well  edited,  and  a  book 
that  covers  many  difficult  problems  in  a  new  way. 


CORRECTION. 

The  book  entitled  "Chemistry  in  the  Ser- 
vice of  Man,"  reviewed  in  the  November 
issue  should  have  been  priced  at  $2.00  in- 
stead of  $1.60. 


WIRELESS  STATION  AT  WILLEM- 
STAD  COMPLETED. 

A  wireless  receiving  station  has  been 
completed  at  Willemstad,  Curacao,  and  be- 
gan operations  on  October  4.  Communica- 
tion was  establisht  with  various  important 
stations.  The  newspapers  now  publish 
news  from  Nauen,  Germany. 

The  station  at  Nauen  is  the  principal  dis- 
tributing point  for  German  wireless  propa- 
ganda. From  this  station  is  sent  the  service 
of  the  Overseas  News  Agency,  which  was 
received  at  Sayville,  N.  Y.,  until  the  United 
States  entered  the  war. 


HOW   TO    BUILD    A  ONE-WATT 
MOTOR. 

(Continued  from  page  545) 
Slip  the  coils  over  the  poles  and  hold 
them  in  place  with  two  small  strips  of  brass 
bent  U-shape  and  having  short  right-angle 
bends  at  their  ends,  which  press  down  in 
between  the  coil  and  the  pole-piece,  but  a 
strip  of  paper  must  be  put  between  this 
brass  holder  and  the  coils  for  there  is  the 
possibility  of  "shorting"  the  two  coils,  one 
to  the  other.  Connect  the  coils  in  series 
and  see  that  they  are  so  hooked  up  that 
the  current  in  passing  produces  a  North 
and  a  South  pole  at  the  business  (armature) 
ends  of  the  field-poles.  This  is  best  done 
by  starting  with  the  end  of  one  coil  and  see 
which  way  the  current  turns,  either  clock- 
wise or  counter  clock-wise  and  connect  the 
other  end  to  the  next  coil  so  that  the  cur- 
rent still  rotates  in  the  same  direction. 

The  last  step  in  construction  is  the  second 
bearing  and  this  is  made  entirely  of  fiber, 
cut  from  a  piece  one-eighth  inch  thick.  This 
is  three-quarters  inch  long  and  one-half 
inch  wide  and  is  cut  as  shown  in  the  draw- 
ing. It  will  be  seen  that  the  ends  of  the  two 
braces  are  filed  a  little  to  fit  under  the 
frame-work  and  a  small  hole  drilled  thru 
frame  and  fiber,  which  enables  you  to  force 
a  large  size  pin  thru  and  lock  the  bearing 
to  the  iron  frame.  It  should  be  noted  that 
the  two  braces  are  placed  between  the  field 
coils,  thereby  making  the  fiber  bearing  lie 
at  right  angles  to  the  brass  bearings  which 
of  course  makes  no  difference  in  the  final 
result.  For  the  brush  support  cut  two 
pieces  from  the  same  brass  tube  that  was 
used  for  the  commutator,  about  one-quarter 
inch  long  and  bore  holes  in  the  braces  just 
large  enough  for  them  to  pass  thru,  but 
before  forcing  them  into  place  solder  two 
thin  copper  strips  three  thirty-seconds  inch 
wide  to  them.  This  is  done  by  cutting  a 
wider  strip  and  boring  holes  in  the  ends 
so  that  the  tubes  can  pass  thru.  After 
soldering  cut  strip  to  proper  width  and  bend 
it  somewhat  like  the  sketch,  so  that  when 
inserted  into  the  fiber  brace  it  rests  on  the 
commutator  with  a  light  but  even  tension. 
The  ends  of  the  field  coils  can  be  forced 


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The  Eastern  Radio  Institute  is  endorsed 
by  the  U.  S.  Government  &  Marconi  Ct. 

EASTERN  RADIO  INSTITUTE 

899B  Boylston  St.      Boston,  Mass. 


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THE  ELECTRICAL  EXPERIMENTER 


December,  1917 


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under  the  strip  where  it  is  soldered  to  the 
tube  and  the  tubes  themselves  act  as  very 
good  binding  posts  for  the  connecting  wires 
from  the  source  of  supply,  which  are  merely 
inserted  into  them.  It  may  be  found  that 
upon  testing  the  motor  runs  backwards. 
This  can  be  remedied  by  reversing  the  field 
connections,  altho  it  don't  make  very  much 
difference  if  the  motor  does  run  in  the 
wrong  direction. 

The  motor  is  of  the  shunt  type,  altho 
it  could  be  connected  for  a  series  type  if 
intended  to  run  on  a  little  higher  voltage 
than  one  or  two  volts.  As  a  shunt  con- 
nected, machine  I  find  that  it  runs  very  well 
on  one  dry  cell  and  draws  somewhere  in  the 
neighborhood  of  one-half  ampere,  more  or 
less.  This  means  that  it  delivers  about 
one-eight-hundredth  of  a  horse-power  and  a 
small  fan  can  be  soldered  to  the  end  of  the 
shaft  so  that  if  the  motor  cannot  be  heard, 
it  can  be  seen  running.  This  fan  need  not 
be  over  five-eighths  inch  in  diameter  and 
has  four  plates;  it  is  cut  from  thin  sheet 
brass.  A  small  brass  case  can  be  made  to 
carry  the  motor  in,  for  after  making  one, 
the  temptation  to  take  it  on  a  visit  is  very 
strong  and  one  does  not  want  to  smash  it 
after  the  time  and  labor  has  been  put  upon 
the  construction  of  the  machine.  I  made  it 
in  about  eighteen  hours  which  is  fairly  good 
time  for  the  first  one,  but  of  course  the 
second  motor  ought  not  to  take  as  long. 

Under  running  conditions  I  find  that  with 
the  proper  voltage  there  is  very  little  spark- 
ing at  the  commutator;  in  fact  sparking  is 
not  known  unless  excessive  voltage  is  ap- 
plied and  this  is  due  to  the  large  brushes  and 
small  current  handled.  Just  a  little  drop  of 
vaseline  on  the  bearings  helps  wonderfully 
and  the  motor  hums  like  a  Jersey  mosquito ; 
it  will  run  for  fifteen  minutes  or  more 
without  undue  heating.  The  power  devel- 
oped can  be  measured  by  letting  the  motor 
wind  up  a  thin  thread  with  pins  stuck  in  it, 
until  just  enough  pins  are  used  so  that  the 
motor  can  pull  them  up  easily.  Then  from 
the  exact  weight  of  the  thread  and  pins 
and  the  distance  they  were  pulled  thru  and 
the  time  it  took  to  do  the  work,  the  frac- 
tional horse-power  can  be  determined. 


THE  HOW  AND  WHY  OF  RADIO 
APPARATUS. 

(Continued  from  page  537) 

out  of  one  turn,  about  two-thirds  the  way 
down  on  any  ordinary  transmitting  helix. 
This  results  in  two  distinct  windings  being 
formed,  as  becomes  evident;  the  shorter 
winding  being  used  as  a  primary  and  the 
longer  one  as  a  secondary.  The  clips  can 
be  moved  along  the  coils  to  vary  the  coup- 
ling as  aforementioned. 

Fig.  6  shows  what  is  known  as  the  trans- 
mitting variometer.  It  is  usual  to  build 
these  non-adjustable  as  to  turns,  and  the  in- 
ductance of  the  instrument  is  varied  by 
simply  moving  the  two  spiral  coils  nearer 
to  each  other  or  farther  apart,  as  the  case 
may  be.  When  the  two  coils  are  brought 
parallel  on  the  same  axis,  and  when  con- 
nected as  shown  in  the  diagram  Fig.  6,  then 
the  minimum  inductance  is  obtained  for  the 
reason  that  one  coil  "bucks"  the  other  or 
the  inductance  of  coil  (2)  neutralizes  that 
of  coil  (1).  When  the  coils  are  drawn  com- 
pletely apart,  their  maximum  inductance  is 
obtained.  The  variation  of  inductance  by 
this  means  is  quite  precisional,  and  the 
"Telefunken"  radio  sets  utilize  this  tuning 
principle  to  a  very  large  extent. 

At  Fig.  7  is  shown  the  method  of  making 
a  continuously  variable  contact  with  trans- 
mitting inductances.  This  trolley  wheel 
contactor  was  first  used  on  Fessenden  radio 
inductances.  Some  of  these,  in  the  larger 
sizes  are  built  of  hollow  copper  tubing,  thru 


which  water  runs  to  carry  away  the  heat, 
and  it  is  interesting  to  note  in  this  respect 
that  a  hollow  tube  is  fully  as  efficient  as  a 
solid  rod,  size  for  size,  in  radio  transmitting 
inductances.  This  is  so  for  the  reason  that 
the  current  at  these  high  frequencies,  vary- 
ing from  50,000  to  300,000  cycles  or  possibly 
more  per  second,  only  penetrate  a  very 
slight  distance  from  the  surface,  due  to 
what  is  known  as  the  "skin  effect."  This  is 
the  reason  why  radio  transmitting  sets  are 
best  hooked  up  with  either  woven  wire  rib- 
bon or  with  a  substantial  flat  copper  strip, 
instead  of  with  a  small  size  round  copper 
wire. 

The  conical  tuning  inductance  shown  at 
Fig.  8  has  come  much  into  favor,  during 
the  past  few  years,  and  provides  one  of  the 
most  efficient  forms  of  radio  frequency  in- 
ductance there  is.  The  primary  as  well  as 
the  secondary  coils  are  made  in  conical 
form  as  shown,  and  the  coupling  is  varied 
by  sliding  one  within  the  other  in  the  usual 
manner.  The  number  of  turns  and  the  posi- 
tion of  the  active  turns  in  use  in  any  case 
is  adjustable,  as  in  the  previous  examples. 

The  principal  advantage  of  this  form  of 
inductance  coil  is  when  a  small  amount 
of  inductance  is  required  only,  the  operator 
has  the  privilege  of  selecting  a  number  of 
smaller  diameter  turns  instead  of  using  one 
or  two  turns  of  large  diameter,  which  is 
less  efficient  owing  to  the  low  flux  density 
in  this  case.  There  are  several  other  de- 
sirable factors  involved  in  the  design  of 
conical  inductances,  such  as  the  rise  in  po- 
tential by  auto-transformer  action  and 
means  for  distributing  this  more  effective- 
ly, and  the  fact  that  a  larger  inductance 
variation  in  a  given  space  can  be  obtained, 
all  things  considered. 

Conical  oscillation  transformers  have 
been  utilized  with  great  success  by  the  Na- 
tional Electric  Signaling  Company.  The 
advantage  of  this  type  of  oscillation  trans- 
former is  that  a  finer  and  closer  mutual  in- 
ductance can  be  obtained,  since  the  movable 
coil  can  be  placed  in  closer  proximity  with 
that  of  the  stationary  one. 

One  of  the  most  efficient  methods  of 
arranging  an  oscillation  transformer,  and 
involving  the  use  of  three  "pan-cake"  in- 
ductances is  shown  at  Fig.  9.  Usually  the 
center  coil  or  "pan-cake"  is  connected  as  the 
primary,  while  the  two  outer  movable  "pan- 
cake" coils  are  connected  in  series  and  form 
the  secondary.  As  the  dotted  lines  indicate 
the  flux  distribution  with  this  arrangement 
is  the  most  efficient  in  that  both  or  the  sec- 
ondary coils  are  in  active  use  in  a  strong 
field  in  contradistinction  to  the  usual  oscil- 
lation transformer  of  this  type,  utilizing  but 
two  "pan-cake"  coils,  in  which  case  the  coil 
acting  as  the  secondary  is  cut  by  only  one 
half  the  flux  that  this  one  is. 


NEW  ELECTRIC  BOMB  DROPPER 
FOR  AEROPLANES. 

(Continued  from  page  511) 

The  other  novel  features  of  this  inven- 
tion consist  of  an  electric  clock  that  drops 
the  bombs  automatically  and  a  fixt  schedule 
or  table  arranged  for  the  aviator  so  that  he 
can  tell  at  a  glance  how  to  set  the  automatic 
bomb  dropper,  after  he  has  decided  on  the 
altitude  from  which  he  will  drop  his  bombs 
and  checked  up  the  speed  at  which  he  is 
flying. 

Suppose  for  example,  he  decides  to  drop 
his  bombs  at  sixteen  hundred  feet  elevation, 
after  checking  up  his  speed  by  sighting  some 
object  several  miles  before  he  reaches  his 
objective.  In  the  right  hand  column  of  the 
schedule  index,  Fig.  4,  opposite  1500  feet 
altitude,  he  will  find  the  degree  or  angle 
at  which  to  fix  his  telescope,  which  is  given 
as  35°.    As  soon  as  he  has  located  this 


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December,  1917 


THE  ELECTRICAL  EXPERIMENTER 


575 


object  over  his  sighting  bars  and  then 
picked  up  his  object  on  the  telescope  cross- 
hairs, he  pushes  the  electric  button  directly 
under  the  clock,  the  face  of  which  is  divided 
into  sixteen  seconds  and  the  space  between 
into  tenths.  This  releases  the  "second"  hand 
and  the  clock  ticks  off  the  seconds ;  when 
he  is  directly  over  his  object  he  reads  the 
time,  and  finds  he  is  flying  say  eighty  miles 
an  hour.  He  then  moves  the  indicator  on 
his  schedule  to  1,500  feet,  80  miles,  and  the 
time  is  shown  directly  opposite — eight 
seconds  and  nine  hundred  eighty-two 
thousands,  which  should  correspond  to  the 
time  he  has  just  taken  to  pass  over  the 
tangent  of  his  triangle,  see  Fig.  1,  which  is 
the  line  from  C  to  B,  at  the  1,500  foot  level. 
At  D,  the  aviator  would  release  his  bomb, 
as  a  projectile  dropt  from  a  moving  object 
is  carried  along  by  the  momentum  for  some 
distance  in  an  arc  before  its  speed  is  dimin- 
ished, is  attracted  by  gravity,  and  starts 
down  on  a  vertical  line.  This  would  have 
to  be  checked  up  by  actual  test  and  deducted 
from  the  schedule  provided. 

The  triangle,  Fig.  1,  is  formed,  first  by 
deciding  on  the  altitude,  then  fixing  the 
telescope  at  the  proper  degree;  this  second 
line  is  variable,  according  to  the  altitude 
determined  on.  The  instant  the  object  shows 
on  the  cross-hairs  of  the  telescope  the  other 
vertical  line  B  of  the  triangle  is  formed  and 
the  aeroplane  flying  at  the  pre-determined 
height  establishes  the  third  line  or  tangent, 
C  to  B. 

The  clock  mechanism  is  run  by  a  spring 
but  is  controlled  by  electricity,  (see  Fig.  7). 
The  "second"  hand  and  "set"  hand  are  in- 
sulated and  connected  on  a  separate  circuit 
from  the  starting  device;  the  hands  close 
the  circuit,  operating  the  arm  of  the  solenoid 
and  releasing  the  catch  which  holds  the 
bomb,  when  the  second  hand  reaches  the  set 
hand.  The  circuits  to  the  bombs  are  changed 
after  each  bomb  is  dropt  by  the  switch,  (see 
Figs.  4  and  7),  or  all  are  dropt  at  once  as 
desired. 

It  is  to  be  noted  that  with  the  Lewis 
device  for  automatically  dropping  bombs 
from  air-craft  it  is  only  necessary  for  the 
bombing  officer  to  take  his  preliminary  sight 
before  he  reaches  the  scene  of  his  activities. 
Then  when  he  "approaches"  the  object  of 
attack  he  turns  the  sighting  telescope  to  the 
predetermined  angle.  Having  done  this  he 
watches  thru  the  telescope  until  he  spots 
the  building,  or  other  object  to  be  bombed, 
and  as  soon  as  it  appears  at  the  intersection 
of  the  cross-hairs,  he  punches  the  clock 
release  button.  The  aviator  has  then  noth- 
ing further  to  do :  flying  at  the  given  al- 
titude, the  machine  is  piloted  over  the  target, 
at  the  speed  allowed  for.  As  the  aeroplane 
passes  over  the  target  (theoretically)  the 
clock  hands  make  contact,  actuating  the 
bomb  releasing  magnet.  As  already  ex- 
plained the  clock  would  be  compensated  so 
as  to  drop  the  bomb  a  short  time  before 
the  object  was  reached. 

To  the  extreme  left  of  the  instrument  is 
an  emergency  lever  so  that  if  the  circuit  for 
any  reason  should  not  work,  the  manual 
control  lever  will  drop  all  the  bombs  to- 
gether. 

At  the  bottom  of  the  board  are  arranged 
four  red  lights  that  light  automatically  as 
each  bomb  is  dropt.  The  illustration  also 
shows  the  arrangement  of  the  bomb  shutes 
in  the  cockpit  of  the  fuselage.  The  red  lamps 
indicate  the  number  of  bombs  that  have 
been  dropt  or  those  that  remain,  so  that  if 
the  aviator  is  interrupted  in  his  work,  he 
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THE  ELECTRICAL  EXPERIMENTER 


December,  1917 


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December,  1917 


THE  ELECTRICAL  EXPERIMENTER 


577 


EXPERIMENTAL  CHEMISTRY. 

(Continued  from  page  571) 
draw  into  the  beaker  a  different  amount  of 
NaOH,  say  15  cc,  and  neutralize  that 
amount.  Make  records  of  results  as  before. 
Find  the  ratio  of  NaOH  solution  to  HC1 
used,  and  reduce  it  to  1  cc.  of  either  the 
NaOH  solution  or  HC1.  Compare  this  re- 
sult with  that  of  the  previous  experiment. 
Is  it  approximately  the  same?  If  not,  re- 
peat it. 

EXPERIMENT  NO.  111.  (Quantita- 
tive.) 

Make  this  experiment  like  the  two  pre- 
vious, only  start  with  20  cc.  of  NaOH  solu- 
tion. Keep  accurate  notes.  Compare  your 
final  results  to  see  whether  a  unit  of  NaOH 
solution  combines  with  approximately  the 
same  amount  of  HC1,  or  vice  versa.  If  it 
does  it  must  illustrate  a  general  law,  namely 
the  law  of  fixt  weight. 

SOME  INTERESTING  NEW  RADIO 
APPARATUS. 

(Continued  from  page  534) 
at  Fig.  2,  is  an  instrument  of  wide  useful- 
ness. It  has  a  range  of  150  to  10,000 
meters  wave  length,  the  calibration  curves 
being  mounted  in  the  lid.  It  is  equipt  with 
hy-tone  buzzer,  battery  in  special  remov- 
able pocket,  crystal  detector,  vacuum  tube, 
'phones,  thermo-couple  and  galvanometer. 
The  condenser  is  calibrated  and  the  four 
inductance  coils  are  wound  on  Bakelite 
spools.    The  exploring  coils  may  be  con- 


nected by  means  of  a  special  flexible  duplex 
connector  as  shown  in  figure,  or  may  be 
connected  rigidly  if  desired.  Special  induc- 
tances can  be  had,  giving  a  higher  wave 
length  range. 

In  the  realm  of  radio  transmitting  keys, 
we  find  the  new  combined  manual  and 
radio  relay  type  shown  at  Fig.  3,  which  has 
a  capacity  of  5  kilowatts  without  over- 
heating. This  key  has  been  approved  for 
use  on  Government  wireless  sets,  and  pos- 
sesses among  other  excellent  qualities  a 
very  strong  hammer  action  in  the  opening 
and  closing  of  the  contacts,  which  are 
of  very  substantial  character. 

One  of  the  most  interesting  of  these  new 
instruments  is  the  "flame-proof"  key  shown 
at  Fig.  4.  This  key  is  intended  especially 
for  use  on  submarines,  aeroplanes  and  di- 
rigible airships,  where  there  is  the  least 
possibility  of  gases  being  present,  and  which 
might  be  ignited  with  disastrous  results  by 
opening  the  usual  key.  As  will  be  seen, 
this  flame-proof  key  comprises  a  substantial 
instrument  of  the  usual  pattern,  with  the 
exception  that  the  contacts  are  opened  and 
closed  in  an  air-tight  compartment.  It  is 
of  very  substantial  design,  and  will  stand 
a  very  heavy  overload. 

The  universal  wave  meter  shown  at  Fig. 
5,  while  not  possessing  some  of  the  fea- 
tures of  the  one  shown  in  Fig.  1,  is  well 
adapted  for  all  ordinary  work,  and 
has  the  advantage  of  rather  a  wide 
range  of  wave  lengths — 200  to  2,600 
meters.  In  its  standard  form  it  includes 
a  variable  air  condenser  mounted  beneath 
a  Bakelite  panel,  with  a  scale  engraved 
with  100  divisions ;  two  inductances  for 
long  and  short  waves — a  simple  crystal  de- 
tector mounted  upon  the  panel  and  a  sin- 
gle high-resistance  'phone,  with  headband. 

Binding  posts  are  provided  for  connect- 


ing in  a  sensitive  hot  wire  meter  or  thermo- 
couple and  galvanometer.  For  all  ordinary 
purposes,  however,  the  crystal  detector  and 
'phone  will  be  found  to  fill  the  requirements. 
The  binding  posts  are  so  arranged  that  the 
detector  may  be  connected  either  double  or 
unilateral.  The  two  inductances  and  'phone 
are  contained  in  compartments  of  the  case, 
which  is  of  oak,  while  the  graph  of  the 
wave  lengths  is  fastened  in  the  lid  of  the 
case,  where  it  may  be  read  easily.  The 
meter  measures  9  by  7l/2  by  5^  inches, 
and  weighs  7  pounds.  It  can  be  furnished 
with  a  third  inductance  to  read  to  12,000 
meters. 

An  interesting  variable  step  inductor  is 
shown  at  Fig.  6,  and  is  intended  particu- 
larly for  use  in  Audion  detector  circuits, 
such  as  those  devised  by  Armstrong.  Two 
or  more  of  these  variable  step  inductor  coils 
may  be  coupled  up  in  duplicate  for  use  in 
the  Armstrong  regenerative  circuit. 

The  receiving  variometer  shown  at  Fig 
7,  is  of  interest  as  these  instruments  have 
been  accorded  more  and  more  recognition 
in  recent  years,  owing  to  their  fine  tuning 
possibilities.  The  variometer  here  shown 
comprises  three  coils,  which  are  connected 
to  a  special  switch,  enabling  the  operator 
to  instantly  throw  the  coil  circuits  in  series 
or  parallel;  thus  changing  the  inductance 
value  of  the  instrument  decidedly. 

The  coils  themselves  are  wound  in  a  self- 
supporting  manner,  and  are  so  proportioned 
in  their  geometrical  and  electrical  dimen- 
sions that  the  losses  in  the  instrument  are 
extremely  small.  The  apparatus  is  provided 
with  an  accurately  graduated  dial  and  in- 
dicator, the  dial  having  one  hundred  di- 
visions. The  indicating  handle  is  station- 
ary, while  the  dial  revolves,  the  latter  being 
rigidly  attached  to  the  rotating  spindles  and 
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THE  ELECTRICAL  EXPERIMENTER 


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THE  MARVELS  OF  RADIO- 
ACTIVITY. 

(Continued  from  page  572) 

And  here  we  have  the  much-talked-of 
modern  alchemy. 

The  action  of  radium  on  human  tissues 
was  unknown  until  1901,  when  Becquerel 
received  his  famous  burn,  fourteen  days 
after  carrying  a  tube  of  active  material  in 
his  pocket  for  several  hours.  Since  that 
time  very  active  investigation  has  taken 
place.  Many  countries  have  establisht 
special  laboratories  for  radium  research. 
The  U.  S.  Government  has  a  large  plant  in 
Denver  for  the  extraction  of  radium  from 
carnotite  ore  to  supply  the  needs  of  hospitals 
and  medical  laboratories. 

The  diseases  which  radium  has  been  ap- 
plied to,  up  to  the  treatments  developed  dur- 
ing the  present  war  and  on  which  we  have 
no  definite  data,  are  papillomata,  lupus 
vulgaris,  epithelial  tumors,  syphilitic  ulcers, 
pigmentary  naevi,  angromata,  and  pruitis 
and  chronic  itching  of  the  skin.  The  dif- 
ferent varieties  of  rays  used  are  controlled 
by  the  use  of  screens  or  filters  of  lead, 
silver  and  aluminum.  Radium  is  analgesic 
and  bactericidal. 

Since  a  large  amount  of  thorium  is 
separated  annually  from  thorium  minerals, 
for  use  in  Welsbach  mantles,  it  would  be 
of  great  importance  at  the  same  time  to 
separate  the  radiothorium  and  mesothorium. 
For  many  purposes  active  preparations  of 
these  substances  would  be  as  valuable  as 
radium  itself,  and  the  supply  of  material 
would  be  greatly  increased. 

Experiments  have  been  carried  on  as  to 
the  effect  of  radio-active  matter  on  plants, 
but  no  definite  results  have  been  compiled 
from  the  mass  of  data  obtained,  and  due 
particularly  to  the  scarcity  of  material  with 
which  to  work. 

(The  End.) 


THE  AUDION  AND  THE  "EDISON 
EFFECT." 

(Continued  from  page  536) 
direct  line  of  the  carbon,  no  effects  were 
recorded  on  the  galvanometer. 

At  that  time  (1884)  quite  a  lengthy  dis- 
cussion took  place  as  to  the  whys  and 
wherefores  of  the  phenomena  thus  evolved 
by  Mr.  Edison,  but  be  that  as  it  may,  we 
can  readily  see  that  the  foundation  of  all 
present  day  valves  was  laid  down  by  Mr. 
Edison's  early  experiments  with  heated  and 
cold  electrodes  within  an  evacuated  cham- 
ber as  here  described. 

Now,  we  "started  something,"  but  these 
statements  are  backed  up  by  proofs  taken 
from  that  time,  and  to  make  a  long  story 
short,  it  does  not  tell  us  how  we  "Radio- 
bugs"  are  going  to  profit  by  this  discovery. 
The  single,  one-step,  two-step,  waltz  or 
any  other  brand  of  Audion  won't  do  us 
much  good,  so  let's  simply  hope  that  some 
day  we  may  again  fish  out  our  "B"  bat- 
teries and  tune  up  for  Nauen  or  the  Eiffel 
Tower. 


THE  UNCROWNING  OF  THE  GIM- 
CRACK  KING. 

(Continued  from  page  540) 
piece  to  the  tail  of  its  predecessor  on  one 
of  several  huge  balls  of  the  same.  The 
piece  he  was  handling  when  I  appeared  was 
about  four  inches  long,  so  I  gathered  that 
every  little  bit  was  expected  to  help,  as  the 
song  goes. 

This  sight  was  not  what  you'd  call  in- 
flaming with  encouragement  to  one  about  to 
propound  royalties  of  ten  to  fifty  dollars  per 
week.  Altho  string  at  that  time  was  more 
expensive  than  now,  it  was  quite  evident 
that  $10.00  would  cover  Mr.  Crowell's  sav- 


ings from  this  source  for  the  rest  of  his 
natural  life ;  and  to  suggest  his  parting 
with  it  for  a  single  delirious  week  of  ad- 
vertising seemed  distinctly  too  forward.  I 
forgot  the  magnificence  of  his  realm  up- 
stairs, his  standing  as,  a  merchant  prince, 
and  the  large  additional  profits  to  accrue 
to  him  thru  my  invention.  With  a  sicken- 
ing sag,  like  the  breaking  of  a  Ford  rear 
spring,  my  asking-price  dropt  to  $5.00,  and 
my  courage  to  one  degree  above  zero  ab- 
solute. In  the  semi-falsetto  of  an  assumed 
breeziness,  it  was  all  I  could  do  to  sputter 
forth,  "M-Mister  Crowell,  may  I  show  you 
something  interesting?" 

Zebediah  grudgingly  allowed  that  I  might, 
altho  he  kept  right  on  with  his  sorting  and 
tying  of  the  strings.  So  with'  shaking 
fingers  I  unpacked  my  big  double  board,  my 
boat  in  its  separate  box,  and  my  two  wet- 
cells. 

Oh,  those  wet-cells  !  I  knew  they'd  been 
slopping,  because  I'd  been  leaving  a  trail 
of  drops  behind  me  for  some  distance;  but 
to  my  horror  I  found  they'd  spilled  so  much 
that  they  would  no  longer  work  my  motor. 

I'd  prepared  to  get  along  with, a  hypo- 
thetical electric  fan;  but  when  I  had  to 
explain  also,  while  poking  the  Mary  Ann 
on  her  course  with  my  finger,  that  the 
gallant  craft  would,  it  most  surely  would 
go  of  its  own  accord  with  proper  battery- 
power,  I  felt  that  imagination  was  carry- 
ing an  overload.  However,  Zebediah 
acknowledged  that  the  thing  was  very 
pretty,  and  when  operating  as  planned  must 
be  decidedly  interesting.  He  thanked  me 
for  taking  so  much  trouble  to  amuse  his 
"idle  hour,"  and  seemed  to  expect  that  I 
would  now  shove  along  to  the  next  citizen 
I  designed  to  favor. 

It  was  an  awkward  moment;  still,  with 
a  lump  in  my  throat  so  large  that  it  seemed 
a  miracle  the  throat  could  hold  it,  I  man- 
aged to  pronounce  a  statement  of  its  great 
value  for  advertising  purposes,  as  demon- 
strated by  Uncle  George's  experience  in 
New  York;  how  his  store  would  be 
thronged  with  watchers  of  the  marvel,  a 
given  percentage  thereof  buying  his  wares. 
Zebediah  was  a  perfect  audience,  in  that  he 
listened  without  a  word ;  but  there  was  a 
quizzical  smile  on  his  face  that  disconcerted 
me.  Father  was  right,  it  didn't  look  in 
the  least  like  money ;  and  when  at  last 
I'd  instructed  Crowell  how  to  run  his  busi- 
ness at  greater  profit,  and  approached  the 
subject  of  my  modest  share  thereof,  what 
was  left  of  the  prospective  $79,920.00  sank 
with  all  on  board,  leaving  on  the  surface, 
like  a  single  bubble,  the  timid  query. 
"W-wouldn't  you  be  willing  to  g-give  me 
something  for  the  use  of  it?" 

Instead  of  shattering  my  hopes,  Zebediah 
was  kind  enough  to  dismantle  them  gently, 
being  able  to  spare  the  time  because  he  was 
also  occupied  with  his  string-ends ;  they 
say  he  never  gave  away  his  time  without 
extracting  the  nutriment  first  in  some  such 
way.  Eye-catching  devices  might  go  in 
New  York,  he  said,  where  there  were  so 
many  strangers,  but  in  our  town  the  need 
was  rather  for  something  to  get  rid  of 
people  who  didn't  come  to  buy;  and  he 
mentioned  with  some  feeling  the  names  of 
a  line  of  inveterate  chair-warmers  who 
spent  all  day  in  his  store  but  never  spent 
anything  else. 

Skilled  by  long  practise  in  avoiding  per- 
sistent drummers,  Zebediah,  having  relieved 
his  mind,  proceeded  to  get  rid  of  me  with 
bewildering  dispatch.  Unstinted  in  his 
praise  of  the  Sailing  Boat,  he  predicted  a 
great  future  for  it — in  New  York,  of 
course,  where  conditions  were  so  favorable. 
He  pronounced  my  father  a  lucky  man  for 
his  opportunity  to  finance  the  undertaking, 


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THE  ELECTRICAL  EXPERIMENTER 


579 


only  I  must  be  careful  not  to  allow  him  too 
large  a  share  of  profits  for  his  aid — some- 
thing adequate,  of  course,  but  strictly 
limited  in  time,  because  frequently  parties 
let  themselves  in  for  very  oppressive  con- 
ditions by  neglecting  that  precaution.  And 
so,  good  day,  and  I  must  be  sure  not  to 
forget  him  when  in  the  market  for  young 
men's  snappy  f urnishing-goods. 

He  talked  me  out  of  the  store,  and  1  dript 
along  home  primed  to  impress  father  with 
visions  of  living  high  at  the  Hoffman 
House,  or  the  Astor,  or  another  of  the  then 
smart  hotels,  while  we  treated  haughtily 
with  suppliant  tradesmen  in  figures  that 
made  my  $79,920.00  blush  with  humility. 

The  old  adage  says  that  it's  darkest  just 
before  the  dawn.  Turn  it  inside  out  (as 
you  can  do  with  any  genuine  adage)  and  it's 
equally  true  that  it's  brightest  just  before 
a  total  eclipse ;  and  my  eclipse  was  ap- 
proaching, strictly  on  schedule  time.  On 
hearing  my  story,  father  was  imprest  all 
right,  but  the  pressure  was  on  the  wrong 
spot.  He  was  a  deliberate  man,  and  before 
replying  he  seemed  to  struggle  with  an 
emotion  of  some  sort.  Having  conquered 
it  and  rectified  the  frontiers,  he  spoke  as 
one  intending  to  give  an  example  of  self- 
restraint:  he  said  he  was  glad  to  know 
there  was  one  thing  that  meddling  old  hypo- 
crite Crowell  would  part  with  freely,  even 
if  it  was  only  hot  air;  that  the  home  town 
exclusively  was  to  be  favored  with  my  des- 
tinies for  many  years  yet ;  that  my  immedi- 
ate future  was  concerned  with  splitting  up 
a  few  slags  for  the  morning's  fire ;  and 
finally,  would  I  please  learn  something  in 
school  conducing  elsewhither  than  to  such 
nauseating  nonsense? 

From  these  neatly  worded  expressions  I 
gathered  that  the  great  merchant's  guid- 
ance of  our  family  affairs  had  not  met  with 
father's  heartfelt  gratitude.  With  an  ex- 
cellent running-start,  my  $79,920.00  was  un- 
questionably beating  it;  and  nothing  has 
occurred  since  to  make  me  doubt  that  it  is 
going  yet. 


THE  SUBMARINE  AND  KINDRED 
PROBLEMS. 

(Continued  from  page  524) 
In  case  the  water  is  more  than  200  feet  in 
depth  a  submarine  must  be  kept  in  motion 
to  obtain  steerage  way  in  order  to  hold  its 
proper  depth  of  submergence.  This  speed 
may  not  exceed  4  or  5  miles  per  hour,  but 
to  remain  submerged,  and  at  the  same  time 
unobserved,  the  water  must  be  at  least  60 
feet  deep. 

The  latest  type  of  submarine  which  is 
being  used  abroad  has  a  surface  speed  of  at 
least  17  knots  per  hour  and  a  submerged 
speed  of  probably  less  than  10  knots.  The 
superior  gun  fire  from  the  merchantman 
which  has  been  properly  equipt  would 
make  it  necessary  for  the  submarine  com- 
mander to  obtain  his  observations,  such  as 
would  permit  accurate  aiming  of  the  tor- 
pedo, during  the  very  brief  interval  of  time 
required  to  come  to  the  surface  for  observa- 
tion thru  the  periscope  and  to  again  sub- 
merge. 

If  running  near  the  surface,  the  peri- 
scope might  be  raised,  a  quick  observation 
.taken,  and  lowered  again  within  30  seconds. 
If,  however,  the  submarine  is  on  the  surface 
and  hatches  uncovered,  from  one  to  four 


minutes  will  be  required  to  completely  sub- 
merge, depending  upon  circumstances. 

A  submarine  of  recent  type  probably  has 
a  total  radius  of  action  of  as  much  as  8,- 
000  miles  when  traveling  at  a  moderate 
cruising  speed  of  from  10  to  11  knots, 
and  may  remain  away  from  its  home-base 
for  as  much  as  one  month,  without  requir- 
ing either  fuel  or  other  supplies  during 
this  period. 

This  type  of  submarine  may  have  as 
many  as  three  periscopes,  two  conning 
towers  and  two  rapid-fire  guns  attached  to 
the  upper  portion  of  its  hull. 

The  vessel  is  steered  by  very  efficient 
gyroscopic  compasses,  which  are  unaffected 
by  extraneous  magnetic  or  electrical  influ- 
ences. 

(a)   Means  for  Discovery 

The  Aeroplane.  When  the  condition  of 
sea  and  air  are  favorable,  a  submarine  is 
readily  discernible  from  an  aeroplane  flying 
at  a  sufficient  height  even  tho  the  sub- 
marine be  submerged  to  a  considerable 
depth. 

While  aeroplanes  have  thus  been  used 
successfully  in  the  English  Channel,  they 


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are  unable  to  fly  far  out  to  sea  where 
the  submarines  are  now  most  active. 
Mother  ships  for  carrying  and  launching 
aeroplanes  might  be  used  in  this  connec- 
tion, but  there  are  only  a  small  number  of 
such  ships  in  operation  and  the  construc- 
tion of  others  under  present  conditions  is 
necessarily  a  slow  process. 

Various  sound-recording  devices,  in- 
tended to  locate  surface-vessels,  sub- 
marines, and  even  moving  torpedoes,  are 
now  being  carefully  tested.  Water  is  an 
excellent  conductor  of  sound,  and  the  de- 
velopment and  improvement  of  such  ap- 
paratus offers  a  promising  field  for  in- 
ventive endeavor  to  those  who  possess  ade- 
quate scientific  training  and  laboratory 
facilities. 

Many  devices  are  suggested  which  de- 
pend upon  optical  means  of  detection,  such 
as  special  forms  of  telescopes  and  field- 
glasses  to  be  mounted  on  ships,  or  on  scout- 
ing vessels.  Many  special  forms  of  search- 
lights and  projectors  have  been  suggested. 
The  fact  that  a  moving  topedo  leaves  in 
its  wake  a  stream  of  air-bubbles  caused  by 
the  exhaust-air  from  its  propelling  engines, 
offers,  under  favorable  conditions,  one 
means  for  discovering  the  approach  of  a 
torpedo.  This  evidence  is,  however,  diffi- 
cult to  detect  in  a  rough  sea  or  at  night, 
and,  furthermore,  the  bubbles  do  not  reach 
the  surface  of  the  water  until  after  the 
torpedo  has  traveled  onward  a  distance  of 
from  50  to  200  feet  towards  its  target. 

The  dragging  of  trawls,  or  nets,  by  spe- 
cial guard-boats,  not  only  with  the  view 
of  locating  submerged  submarines  but  also 
to  sweep  up  floating  and  stationary  mines, 
is  frequently  suggested.  Under  certain 
conditions  this  operation  is  practicable  and 
effective. 

It  will  be  seen  that  each  of  the  above 
methods,  however  useful,  has  its  limitations, 
and  scientists  and  inventors  should  apply 
themselves  not  only  to  the  task  of  improv- 
ing these,  but  also  of  finding  supplemen- 
tary methods  and  devices. 


(b)  Protection  of  Cargo-Carrying  Ships  by  Nets 
or  Screens 


Many  designs  of  such  devices  are  sug- 
gested, and  most  of  them  are  intended 
to  be  attached  to  the  hull  of  the  vessel 
to  be  protected.  Many  other  suggestions 
along  these  lines,  and  differing  only  in  some 
of  their  minor  characteristics  from  the  fore- 
going, have  been  received  by  the  Board. 
Up  to  the  present  time  not  one  of  these 
proposals  involving  screens  of  any  kind 
has  received  the  approval  of  the  Navy  De- 
partment or  of  the  Merchant  Marine.  The 
principal  objections  offered  to  these  de- 
vices are  that  they  are  heavy,  difficult  to 
hold  in  position,  unmanageable  in  a  heavy 
sea,  and  that  they  interfere  with  the  speed 
and  with  the  ability  of  the  vessel  to  ma- 
neuver. The  undeniable  evidence  which 
has  been  accumulated  during  the  past  few 
months  of  submarine  activity  has  demon- 
strated that  the  immunity  of  a  vessel  to 
submarine  attack  is  dependent  very  largely 
on  its  speed  and  also  its  maneuvering 
ability.  The  percentage  of  vessels  having 
speeds  of  15  knots  or  more  which  have 
suffered  from  submarine  attack  is  very 
small,  while  the  losses  of  slow  vessels, 
whose  speed  is  less  than  that  of  a  sub- 
merged submarine,  is  practically  one  hun- 
dred per  cent  of  those  attacked.  Many  of 
the  suggested  devices  would  prevent  the 
launching  of  life-boats  or  rafts  from  the 
vessel  to  be  protected.  It  is  barely  pos- 
sible, however,  that  there  may  be  developed 
some  form  of  this  general  plan  which  will 
be  found  practicable.  In  no  other  field 
have  so  many  suggestions  or  so  many  du- 
plicate inventions  been  presented  to  the 
Board. 


(c)  Protection  Thru  Invisibility 

The  point  of  lookout  on  a  submarine  be- 
ing close  to  the  water,  the  position  of  a 
vessel  at  a  distance  can  only  be  determined 
by  observing  its  smoke,  which  floats  high 
in  the  air.  Improved  smokeless  combus- 
tion is  therefore  desirable.  Relative  in- 
visibility may  also  be  afforded  by  methods 
of  painting. 

(d)  Destruction  and  Blinding  of  the  Submarines 

A  rapid-fire  gun  is  effective  when  the 
submarine  is  seen  within  accurate  range 
of  the  gun ;  but  the  target  is  so  small  that 
it  is  difficult  to  hit. 

The  powerful  effect  of  any  submarine 
explosion  on  all  neighboring  bodies  pro- 
vides a  simple  means  of  destroying  or 
crippling  an  undersea  boat.  Once  it  has 
been  even  approximately  located,  the  set- 
ting-off of  a  heavy  charge  of  high  ex- 
plosive, well  submerged  in  the  vicinity  of 
the  submarine,  will  bring  about  this  re- 
sult. 

In  certain  areas,  a  quantity  of  heavy, 
black  petroleum  or  similar  substance  which 
will  float  on  the  surface  of  the  water  has 
proved  an  effective  means  of  clouding  the 
optical  glass  in  the  periscope's  exposed 
end. 

Under  favorable  conditions  of  wind  and 
position,  many  vessels  have  saved  them- 
selves from  torpedo  attack  by  the  produc- 
tion of  a  smoke  screen.  This  may  be 
formed  either  by  incomplete  combustion 
of  the  oil  used  for  fuel  by  most  naval 
vessels,  or  it  may  be  created  by  burning 
chemicals,  such  as  phosphorous  and  coal 
tar,  or  mixtures  in  which  both  of  these 
and  other  materials  are  used. 

After  hiding  itself  from  the  submarine 
in  a  cloud  of  dense  smoke,  the  vessel,  if 
possest  of  sufficient  speed,  may  be  able 
by  a  quick  maneuver  to  change  her  posi- 
tion and  escape  before  the  submarine  is 
able  to  discharge  a  torpedo. 

MINES  AND  TORPEDOES  FOR  NAVAL 
OPERATIONS 

(a)  Mines 

Ever  since  the  first  use  of  gunpowder 
in  the  prosecution  of  war,  mines  and  tor- 
pedoes have  received  great  attention  both 
from  the  warrior  and  the  inventor.  Mines 
are  either  fixt  or  floating.  The  fixt 
or  stationary  submarine  mine  is  fired 
by  contact,  electricity,  timing  device  or 
fuse.  Such  mines,  which  are  extensively 
used  by  all  navies,  are  rugged  in  design 
and  may  contain  large  charges  of  explo- 
sives. They  are  placed  in  position  by  es- 
pecially equipt  mine-laying  vessels.  Such 
a  mine  is  provided  with  an  anchoring 
device. 

Floating  mines  differ  from  fixt  mines 
in  that  they  are  unanchored,  and,  unless 
guard  boats  are  at  hand  to  warn  friendly 
vessels  of  their  proximity,  may  be  as  dan- 
gerous to  friend  as  to  foe.  Such  mines 
must  be,  according  to  laws  of  war,  de- 
signed to  become  inoperative  within  a  few 
hours  after  being  set  adrift. 

(b)  Torpedoes 

The  modern  submarine  torpedo  is  about 
20  inches-in  diameter  and  20  feet  in  length: 
is  self-propelled;  is  not  steered  by  mag- 
netic means;  and  keeps  a  fairly  accurate 
course  for  several  thousand  yards  at  an 
average  speed  of  more  than  30  miles  an 
hour.  Its  weight  is  approximately  a  ton 
and  a  quarter;  and,  when  traveling  at  nor- 
mal speed,  possesses  great  momentum — in 
fact,  in  one  case,  when  the  high  explosive 
charge  in  the  "warhead"  failed  properly 
to  detonate,  the  body  of  the  torpedo  pene- 


You  benefit  by  mentioning  "The  Electrical  Experimenter"  when  writing  to  advertisers. 


December,  1917 


THE  ELECTRICAL  EXPERIMENTER 


581 


trated  the  steel  hull  of  the  ship  attacked. 
Torpedoes  are  also  provided  with  means 
to  more  or  less  effectively  cut  through 
screens,  nets,  or  guards  placed  in  their 
path. 

A  torpedo  is  projected  from  a  submarine 
or  other  vessel  by  means  of  a  special  form 
of  tube  or  gun.  A  small  charge  of  gun- 
powder or  comprest  air  is  employed 
to  start  the  torpedo,  after  which — if  of 
the  usual  self-propelling  type — it  is  driven 
through  the  water  by  its  own  comprest 
air  motor,  the  air  being  supplied  from  a 
strongly  built  reservoir  within  the  body 
of  the  torpedo  itself.  The  torpedo  is  kept 
upon  its  course  by  a  gyroscope  steering 
mechanism,  which  is  immune  to  outside 
magnetic  disturbances. 

The  detonation  of  the  torpedo  is  accom- 
plished through  a  mechanism  placed  with- 
in its  warhead;  and  if  the  torpedo  is  either 
abruptly  diverted  from  its  course  or  is 
checked  in  its  forward  motion,  the  firing 
device,  which  is  operated  by  arrested 
momentum  rather  than  by  any  form  of  a 
projecting  firing-pin,  instantly  ignites  the 
heavy  charge  of  explosive  contained  with- 
in the  warhead.  The  explosion,  if  it  takes 
place  within  twenty  feet  of  the  vessel,  will 
usually  rupture  the  ship's  plating,  because 
of  the  terrific  blow  transmitted  through  the 
water  from  the  point  of  the  explosion  to 
the  ship's  side.  The  depth  at  which  a  tor- 
pedo travels  is  usually  between  12  and  15 
feet  below  the  surface. 

Confining  the  Submarines 

The  question  as  to  why  submarines  are 
not  destroyed  before  they  reach  the  open 
sea  is  a  most  natural  one,  and  the  best 
answer  which  it  is  possible  to  give,  ac- 
cording to  the  officers  of  our  Navy  and 
those  of  the  foreign  commissions  who 
have  visited  this  country,  is  as  follows : 

The  submarine  bases  are  very  strongly 
protected  by  land  batteries,  aeroplane  ob- 
servers and  large  areas  of  thickly  mined 
waters  extending  to  such  distances  that 
the  largest  naval  gun  cannot  get  within 
range  of  the  bases.  In  spite  of  these  pro- 
tections, there  is  now  going  on  a  contin- 
uous attempt  on  the  part  of  the  Allied 
navies  to  entrap  or  otherwise  defeat  the 
submarines  as  they  emerge  from  the  pro- 
tected areas.  Nets  are  laid  and  as  promptly 
removed  by  the  enemy,  whose  trawlers  are 
in  turn  attacked  by  our  destroyers.  The 
design  of  these  nets  and  the  detailed  ar- 
rangement of  their  fastenings  and  attach- 
ments offer  a  broad  field  for  invention, 
but  it  should  be  remembered  that  they 
must  be  capable  of  being  used  in  waters 
in  which  there  is  a  tidal  current  running 
from  two  to  five  miles  per  hour.  Many 
suggestions  for  "bottling  up"  these  bases 
have  been  offered,  but,  as  will  be  realized, 
it  is  not  desirable  to  publish  information 
which  would  indicate  even  in  the  smallest 
degree  this  country's  plans. 

Ships  and  Shipbuilding 

Many  suggestions  are  made  for  ships 
of  unusual  form  to  provide  for  safety  in 
case  of  a  torpedo  or  mine  exploding  near 
or  against  the  hull.  Most  of  these  plans 
are  an  elaboration  of  the  usual  watertight 
bulkhead  construction  now  required  as 
structural  design  for  all  modern  ships. 

The  multiplicity  of  waterfront  compart- 
ments in  any  hull  design  tends  to  add  to 
the  vessel's  safety. 

The  modern  tank  steamer  used  to  carry 
fluid  cargoes,  such  as  petroleum  products 
or  molasses,  is  a  good  example  of  this 
design,  which  has  been  in  general  use  for 
many  years. 

The  explosion  of  a  nearby  submarine 
mine   or   torpedo   frequently   tears  great 


rents  in  the  ship's  plating,  in  some  cases 
opening  a  jagged  hole  ten  feet  or  more 
across,  but  the  destructive  effect  on  the 
hull  of  a  ship  caused  by  the  explosion  of 
a  mine  or  torpedo  may  be  greatly  dimin- 
ished by  special  hull  construction. 


General  Instructions  to  Those  Offering  Sugges- 
tions to  the  Naval  Consulting  Board 


A  very  large  proportion  of  the  letters 
and  plans  that  are  received  describe  de- 
vices or  schemes  which  are  obviously  im- 
practicable or  which  show  no  novelty  or 
improvement  as  compared  with  existing 
methods.  After  the  elimination  of  these, 
the  more  meritorious  inventions  are  sub- 
mitted to  the  various  standing  committees 
of  the  Board  for  examination.  If  an  in- 
vention receives  the  approval  of  a  stand- 
ing committee,  it  is  presented  to  the  Board 
with  a  favorable  report  and,  if  then  again 
approved,  it  is  forwarded  to  the  Navy  De- 
partment with  the  endorsement  of  the 
Board. 

The  fact  that  inventions,  plans  and  de- 
vices must  be  forwarded  to  the  various 
departments  of  the  Board  for  examina- 
tion makes  it  essential  that  everything  be 
presented  in  writing. 

Communications  should  be  addrest : 
Thomas  Robins,  Secretary,  Naval  Con- 
sulting Board,  13  Park  Row,  New  York, 
N.  Y. 

Presumably  the  Government  intends  to 
pay  for  inventions  which  it  adopts,  but  as 
yet  no  specific  provision  has  been  made 
by  laiv  for  this  purpose. 


Statement  of  the  Ownership,  Management, 
Circulation,  etc..  Required  by  the  Act  of  Con- 
gress of  August  24,  1912,  of  The  Electrical 
Experimenter,  publisht  monthly  at  New  York, 
N.  Y.,  for  Oct.  1,  1917.  State  of  New  York, 
County   of   New   York,  ss. 

Before  me,  a  Notary  Public  in  and  for  the 
State  and  county  aforesaid,  personally  appeared 
Hugo  Gernsback,  who,  having  been  duly  sworn 
according  to  law,  deposes  and  says  that  he  is  the 
Editor  of  The  Electrical  Experimenter  and 
that  the  following  is,  to  the  best  of  his  knowledge 
and  belief,  a  true  statement  of  the  ownership,  man- 
agement (and  if  a  daily  paper,  the  circulation), 
etc,  of  the  aforesaid  publication  for  the  date  shown 
in  the  above  caption,  required  by  the  Act  of 
August  24,  1912,  embodied  in  section  443,  Postal 
Laws  and  Regulations,  printed  on  the  reverse  of 
this  form,  to  wit: 

1.  That  the  names  and  addresses  of  the  pub- 
lisher, editor,  managing  editor,  and  business  man- 
agers are:  Publisher,  The  Experimenter  Publish- 
ing Co.,  233  Fulton  St.,  New  York  City;  Editor, 
Hugo  Gernsback,  233  Fulton  St.,  New  York  City; 
Managing  Editor,  Hugo  Gernsback,  233  Fulton  St., 
New  York  City;  Business  Manager,  Hugo  Gerns- 
back, 233  Fulton  St.,  New  York  City. 

2.  That  the  owners  are:  The  Experimenter 
Publishing  Co.,  233  Fulton  St.,  New  York  City; 
Hugo  Gernsback,  233  Fulton  St.,  New  York  City; 
Sidney  Gernsback,  233  Fulton  St.,  New  York  City; 
Mrs.  K.  Hymes,  233  Fulton  St.,  New  York  City; 
H.  W.   Secor,  233  Fulton  St.,  New  York  City. 

3.  That  the  known  bondholders,  mortgagees,  and 
other  security  holders  owning  or  holding  1  per  cent 
or  more  of  total  amount  of  bonds,  mortgages,  or 
other  securities  are:  None. 

4.  That  the  two  paragraphs  next  above,  giving 
the  names  of  the  owners,  stockholders,  and  security 
holders,  if  any,  contain  not  only  the  list  of  stock- 
holders and  security  holders  as  they  appear  upon 
the  books  of  the  company  but  also,  in  cases  where 
the  stockholder  or  security  holder  appears  upon 
the  books  of  the  company  as  trustee  or  in  any  other 
fiduciary  relation,  the  name  of  the  person  or 
corporation  for  whom  such  trustee  is  acting,  is 
given;  also  that  the  said  two  paragraphs  contain 
statements  embracing  affiant's  full  knowledge  and 
belief  as  to  the  circumstances  and  conditions  under 
which  stockholders  and  security  holders  who  do  not 
appear  upon  the  books  of  the  company  as  trustees, 
hold  stock  and  securities  in  a  capacity  other  than 
that  of  a  bona  fide  owner;  and  this  affiant  has  no 
reason  to  believe  that  any  other  person,  association, 
or  corporation  has  any  interest  direct  or  indirect 
in  the  said  stock,  bends,  or  other  securities  than 
as  so  stated  by  him. 

H.  GERNSBACK. 
Sworn  to  and  subscribed  before  me  this 
15th  day  of  October,  1917. 
E.  D.  JUNIOR, 

(My  commission  expires  March  10,  1919.) 


FREE 

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THE  ELECTRICAL  EXPERIMENTER 


December,  1917] 


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Etude    1 


50 


Regular  Price  $4.50 


Our  Price 

$3.45 


Electrical  Experimented!. 50 

Youth's  Companion...  2.00 
Review  of  Reviews  3.00 


Regular  Price. . . 


.$6.50 


Our  Price 

$5.15 


Electrical  Experimented  1.50 

Woman's    Home  Com- 
panion   1.50 

American  Magazine...  1.50 
(All  to  one  address) 


Regular  Price... 


Our  Price 


Special  Clubbing  Prices  of  Electrical  Experimenter  WITH: 


Regular 
Price 

Adventure   $4.50 

American  Boy    3.00 

American  Magazine  ....  3.00 

Black  Cat    2.50 

Blue  Book    3.00 

Boys'  World    2.00 

Century    5.50 

Christian  Herald    3.50 

Collier's    4.00 

Country  Life    6.50 

Delineator    3.00 

Etude    3.00 

Everybody's    3.00 

Farm  &  Fireside   1.75 

Farm  Journal  (5  years)  2.50 

Farmer    2.50 

Field  &  Stream    3.50 

Film  Fun    2.50 

Grit    3.50 

Illustrated  World  (Tech- 
nical World)    3.00 

Judge  Weekly    6.50 

Ladies'  World    2.50 


Our  Rate 
Per  Year 
$3.80 
2.25 
2.30 
1.85 
2.40 
1.45 
4.35 
2.65 
2.90 
4.65 
2.35 
2.25 
2.35 
1.35 
1.80 
1.90 
2.65 
1.85 
2.75 

2.25 
5.40 
1.75 


Regular 
Price 

(Leslie's  Weekly    6.50 

Literary  Digest    4.50 

McClure's  Magazine  ....  3.00 

Metropolitan    3.00 

Modern  Priscilla    2.75 

National  Magazine  ....  4.50 

Outing    4.50 

Outlook    5.50 

Pearson's  Magazine  ....  3.00 
People's  PopulaDMonthly  2.00 
Popular  Science  Monthly  3.00 

Red  Book    3.50 

Review  of  Reviews   4.50 

Rural  New  Yorker   2.50 

St.   Nicholas    4.50 

Scientific  American  ....  5.50 
Scribner's  Magazine  . . .  5.50 

Smart  Set    4.50 

Wireless  Age    3.50 

Woman's   Home  Com- 
panion   3.00 

World's  Work    4.50 

Youth's  Companion  ....  3.50 


Our  Rate 
Per  Year 
5.40 
4.15 
2.25 
2.40 
2.15 
3.15 
3.65 
4.65 
2.25 
1.45 
2.30 
2.85 
3.15 
2.05 
3.40 
4.45 
4.15 
2.90 
2.65 

2.30 
3.40 
3.15 


Write  for  Special  Prices  on  ANY  Publication  not  listed  here 
We  will  save  you  money 
SEND  ALL  ORDERS  TO  "CIRCULATION  DEPARTMENT" 

EXPERIMENTER  PUBLISHING  CO.,  Inc. 

233  Fulton  Street,  New  York  City,  N.  Y. 


You  benefit  by  mentioning  "The  Electrical  Experimenter"  when  writing  to  advertisers. 


December,  1917 


THE  ELECTRICAL  EXPERIMENTER 


583 


3f? 


Opportunity  Exchange 

tunities  and  real  bargains  in  these  columns  than  anywhere  else 

going  after — these  little  ads  illustrate  that  point;  you  alone  will  be  the  real  loser  if  you  don't  take  the 


VOU  will  probably  find  more  opportunities  and  real  bargains  in  these  columns  than  anywhere  else  in  the  country.  Most  good  things  in 
-1    life  are  hard  to  find  and  worth  going  after — these  little  ads  illu 


time  to  scan  through  these  columns. 

Advertisements  in  this  section  six  cents  a  word  for  each  insertion.    Count  7  words  per  line. 

Name  and  address  must  be  included  at  the  above  rate.  Cash  should  accompany  all  classified  advertisements  unless  placed  by  an  accredited 
advertising  agency. 

Ten  per  cent,  discount  for  6  issues,  20  per  cent,  discount  for  12  issues  from  above  rate.  Objectionable  or  misleading  advertisements  not 
accepted. 

Advertisements  for  the  January  issue  should  reach  us  not  later  than  November  24. 

OVER  80,000  PEOPLE  READ  THIS  JOURNAL 

EXPERIMENTER  PUBLISHING  CO.,  INC.,  233  Fulton  Street,  New  York,  N.  Y. 


AERONAUTICS 


HELP  WANTED 


PHONOGRAPHS 


AERIAL  AGE,  America's  leading  illustrated 
weekly,  presents  the  latest  developments  in  aeronau- 
tics throughout  the  world.  Up  to  the  minute 
technical  information  concerning  aero-engines,  aero- 
planes, accessories  and  patents.  Complete  model 
news  and  instruction.  Trial  subscription  six 
months,  twenty-six  issues,  one  dollar.  Sample  copy 
10c.  Aerial  Age,  280  Madison  Ave.,  New  York 
City.  N.  Y.  


AUCTIONS 


AUCTIONEERS  make  from  $10  to  $50  a  day. 
Free  catalog.  Missouri  Auction  School,  Kansas 
City.  


BOOKS 


TO  GET  BETTER  PICTURES:  Read  the 
Amateur  Photographer's  Weekly;  illustrated;  week- 
ly prize  competitions;  print  criticisms;  many  unique 
features;  $1.50  per  year;  three  months'  trial  sub- 
scription 25c;  Abel  Publishing  Company,  401 
Caxton  Bldg.,  Cleveland,  Ohio.  

30  MAGAZINES— All  different,  late  issues. 
Value  $3.  Yours,  only  25c  prepaid.  Eastern 
Bureau,  New  Egypt,  N.  J.  

A  BINDER  for  THE  ELECTRICAL  EXPERI- 
MENTER will  preserve  your  copies  for  all  time. 
Price,  50c.  Postage  on  3  lbs.  is  extra.  Send  for 
one  today.  Experimenter  Publishing  Co.,  233  Ful- 
ton  St.,  New  York  City.  

FIRE  SALE  OF  SLIGHTLY  DAMAGED 
BOOKS.  Due  to  fire  in  our  stock  rooms,  a  great 
many  of  our  books  were  water  stained,  but  not 
otherwise  damaged.  Rather  than  dispose  of  them 
to  dealers  we  prefer  to  give  our  readers  the  bene- 
fit. Look  at  this  list!  Our  celebrated  Wireless 
Course,  160  pages,  400  illustrations;  Experimental 
Electricity  Course,  160  pages,  350  illustrations;  How 
to  Make  Wireless  Sending  Instruments.  These 
three  books  for  $1.00  prepaid.  Regular  selling 
price  of  these  three  books  is  $2.50.  We  guarantee 
you  will  be  satisfied.  Experimenter  Publishing  Co., 
Inc.,  233  Fulton  St.,  New  York  City.  

OLD  E.E.  BACK  NUMBERS— We  have  some 
valuable  old  E.E.  back  numbers  on  hand  as  per 
list  below: 


1915. 
Jan. 
Feb. 

March  ... 
April  ... 
May 

June  .. . , 

July   

August  .. 

Sept  

Oct  

Nov.  . . . 
Dec.   

1916. 
Jan  

Feb  , 


price  each  $.25 


March    .  .price  each  $.20 
April    . . . 
May  .... 
"       June  .... 

July  .... 
"       August  ., 

"  Sept  

Oct  

"  Nov  

"  Dec  

1917. 

Jan   "      "  .15 

Feb  

March  ... 
April    .  . . 

.20  May   

"       June  .... 
July  .... 

Aug  

Sept  

Oct  

Nov  

We  can  fill  orders  at  once  upon  receipt  of  your 
remittance  and  if  ycu  have  not  these  numbers  al- 
ready now  is  your  chance  to  get  them  as  they 
probably  will  be  snapped  up  very  quickly.  Ex- 
perimenter Publishing  Co.,  233  Fulton  St.,  New 
York  City. 

BUSINESS  OPPORTUNITIES 

SPECIAL  OFFER— Luminous  Paint,  15c;  Sil- 
ver-plating Powder,  15c;  Liquid  Courtplaster,  15c; 
Soap  Bubble  Liquid,  15c;  Straw  Hat  Bleach,  15c; 
Collapsible  Tube  Tooth  Paste,  15c  Resilvering  Mir- 
ror Liquid,  15c;  Polish  for  Tan  Shoes,  15c;  Dress- 
ins:  for  Tan  Shoes,  15c;  Paint  to  Make  Oil  Cloth, 
15c.  Full  Directions  how  to  make  and  use.  Full 
set  of  10  only  50c.  Remarkable  bargain.  Stamps 
accepted.  Sidney  Specialty  Co.,  233  S.  Fulton  St., 
New  York  City. 

CHFMICALS 

CHEMICAL  LABORATORIES  for  the  Experi- 
menter. Prices  low  as  $1.25,  with  100  experiments. 
Our  genuine  College  Course  in  Chemistry  free, 
with  diploma  when  completed,  to  anyone  purchas- 
ing our  Laboratories  listed  at  $5  and  upward.  Send 
stamp  for  complete  descriptive  matter.  North- 
western Ohio  Specialty  Co.,  Box  493,  Central  Sta- 
tion, Toledo,  Ohio. 


WANTED  MEN  AND  WOMEN,  18  or  over, 
everywhere,  for  U.  S.  Government  Life  Jobs,  War 
necessitates  hundreds  appointments,  $75  to  $150 
month.  Short  hours,  Vacations  with  pay.  Com- 
mon education  sufficient.  Write  immediately  for 
list  positions  open.  Franklin  Institute.  Dept. 
J  27,  Rochester,  N.  Y. 

ELECTRICAL  SERVICE  ME  N 

Young  men  to  enter  factory  of  well-known  firm 
for  3  months  thorough  training  in  manufacture  of 
electric  motors.  Will  then  be  attached  to  branch 
offices  in  large  cities  to  do  special  service  and 
repair  work.  Splendid  chance  to  work  from  this 
to  position  as  sales  engineer.  Technical  training 
desirable,  but  not  necessary.  Practical  experience 
in  electrical  work  will  count.  Reply  in  full  stat- 
ing education,  experience,  habits,  references, 
whether  married  and  your  liability  to  military  ser- 
vice, also  send  photo.  Replies  strictly  confidential 
between  you  and  the  general  manager.  Address 
Box  300,  care  Electrical  Experimenter. 

MISCELLANEOUS 

AMERICANS!  Set  of  twenty-four  cards  each 
5'A-x.3'/2,  picturing  America's  Celebrities  with  a 
short  history  of  each,  20c  a  set;  3  for  50c.  Henry 
Ringer,  28  W.  Liberty  St.,  Cincinnati,  Ohio.  

SHEET  MUSIC  BARGAINS— 6  for  25c. 
Reubin   Scholz,   Scheboygan,  Wisconsin. 

WE  HAVE  a  limited  number  of  beautiful  art 
pictures  of  the  following  famous  electrical  men  on 
hand.  Nikola  Tesla,  Dr.  Lee  De  Forest,  Guglielmo 
Marconi,  Charles  P.  Steinmetz  and  Reginald  A. 
Fessenden.  These  make  a  handsome  decoration 
for  any  laboratory  or  workshop  and  should  be 
prominently  displayed.  Price  tor  five,  prepaid, 
25c.  Experimenter  Pub.  Co.,  233  Fulton  St.,  New 
York  City.  

BIG  BARGAIN  IN  TENNIS  RACKETS— 
We  have  a  small  supply  of  Tennis  Rackets,  made 
by  one  of  the  largest  firms  in  the  country,  on  hand 
which  we  will  close  out  at  the  following  prices: 
No.  2375 — Extra  best  Tennis  Racket,  $5  grade,  air 
dried  ash,  popular  long  oval  form,  concave  walnut 
wedge,  superior  quality  of  gut;  each,  $2.75. 
No.  2377 — First  grade  Tennis  Racket,  second 
growth  ash,  walnut  and  maple  throat,  very  good 
grade  of  gut;  handle  of  cedar  with  leather  cap;  a 
$3.25  grade;  each  $1.85. 

No.  2376 — Medium  grade  Tennis  Racket  made  of 
the  same  stock  as  No.  2377  except  the  gut.  A  per- 
fect $2.25  grade.  Ideal  for  beginners.  Each  $1.35. 
Shipping  weight  of  each  size  two  pounds.  Send 
for  one  today.  Our  stock  is  limited  and  policy  is: 
"First  Come,  First  Served."  Don't  forget  to  in- 
clude money  for  postage,  or  we  ship  express  collect. 
The  Electro  Importing  Co.,  233  Fulton  St.,  New 
York  City. 

SEND  YOUR  SOLDIER  BOYS  a  little  pas- 
time amusement.  My  six  baffling  puzzles  and 
tricks  are  just  the  thing.  Complete  set  for  one 
dime.    H.  J.  Kunow,  2246  N.  Tripp  Ave.,  Chicago. 

PATENT  ATTORNEYS 

IDEAS  WANTED — Manufacturers  are  writing 
for  patents  procured  through  me.  Four  books 
with  list  hundreds  of  inventions  wanted  sent  free. 
I  help  you  market  your  invention.  Advice  Free. 
R.  B.  Owen,  130  Owen  Bldg.,  Washington,  D.  C. 

PATENTS— R.  Morgan  Elliott  &  Co.,  Patent 
Attorneys,  Mechanical,  Electrical  and  Chemical 
Experts.  716-724  Woodward  Bldg.,  Washington,  D.C. 

PATENTS — Without  advance  attorney's  fees. 
Not  due  until  patent  allowed.  Send  sketch  for 
free  report.  Books  free.  Frank  Fuller,  Wash- 
ington,  D.  C.   

PATENTS  ON  EASY  PAYMENTS— Send 
model  or  sketch  for  Free  Search  and  Certified 
Registration  of  Your  Invention  for  Your  Protec- 
tion. Free  Book  Tells  What  to  Invent  and  How 
to  Obtain  a  Patent  on  Easy  Payments.  C.  C. 
Hines  &  Co.,  593  Loan  &  Trust  Bldg.,  Washing- 
ton,  D.  C.  

FETHERSTONAUGH  &  CO.— 403  Victor 
Bldg.,  Washington,  D.  C. — A  35  year  old  firm 
composed  of  young  men  for  energy  and  push, 
and  older  men  for  counsel.  All  trained  patent 
lawyers.     Free  Booklet. 


BUILD  YOUR  OWN  PHONOGRAPH  or  manu- 
facture them  for  profit.  Drawings,  instructions, 
etc.,  Twenty-five  Cents.  Satisfaction  guaranteed. 
Circular  free.  Associated  Phonograph  Co.,  Dept. 
E,  Cincinnati. 

BUILD  your  Phonograph.  Highest  quality  mo- 
tors, tone  arms,  reproducers,  cabinets.  Big  sav- 
ing. Handsome  catalog  free.  Indiana  Phonograph 
Supply  Co.,  Indianapolis,  Indiana. 

STAMPS 

STAMPS— 61,  all  different,  free.  Postage  3c. 
Mention  paper.    Quaker  Stamp  Co.,  Toledo,  Ohio. 

FINE  HIGH  GRADE  APPROVALS,  state  size 
of  collection.  Sycamore  Stamp  Co.,  3206  Syca- 
more Rd.,  Cleveland,  Ohio. 

STAMPS— 100  different  U.  S.  7c,  or  100  dif- 
ferent  foreign,  12c.  A.  J.  Janecek,  3608  Clark 
Ave.,  Cleveland,  Ohio. 

TELEGRAPHY 

TELEGRAPHY— both  MORSE  AND  WIRE- 
LESS,  also  STATION  AGENCY,  taught  quickly. 
TREMENDOUS  DEMAND— much  greater  than 
supply— PERMANENT  POSITIONS  SECURED. 
BIG  SALARIES  —  recently  raised.  IDEAL 
WORKING  CONDITIONS— short  hours,  vaca- 
tions with  pay,  sick  and  death  benefits,  etc. — pre- 
vailing. GREAT  OPPORTUNITIES  FOR  AD- 
VANCEMENT. WOMEN  OPERATORS  also 
greatly  desired  by  Railways  and  Western  Union. 
Tuition  reasonable.  Cheap  living  expenses — can 
be  earned.  Oldest  and  largest  school — established 
43  years.  Endorsed  by  railway,  Western  Union 
and  Marconi  Telegraph  Officials.  Large  illustrated 
catalogues  free.  Correspondence  courses  also. 
Write  today.  ENROLL  IMMEDIATELY.  Dodge's 
Institute,  Lone  St.,  Valparaiso,  Indiana. 

100,000  MEN  NEEDED  IMMEDIATELY  to 
serve  as  radio  operators  in  Signal  Corps,  subma- 
rine chasers,  battleplanes,  and  merchant  marine. 
GRACELAND,  a  fully  standardized  and  officially 
accredited  junior  college,  offers  TWO  COURSES: 
EIGHTEEN  WEEKS  INTENSIVE  TRAINING, 
and  RADIO  SUPPLEMENTARY  COURSE 
with  which  other  work  can  be  taken  in  the  regular 
college  departments — collegiate,  academy,  short- 
hand, typewriting,  stenotypy,  conservatory,  etc. 
Both  courses  lead  to  commercial  operators  license, 
first  grade.  Recognized  by  U.  S.  Government  as 
a  RADIO  OPERATORS'  TRAINING  SCHOOL. 
GRADUATES  GUARANTEED  POSITIONS  with 
commercial  companies  or  government,  as  desired. 
Radio  students  participate  in  all  college  activities, — 
athletics,  literary,  glee  club.  MILITARY,  etc.  Ex- 
traordinary LOW  TUITION  AND  EXPENSES; 
student  self-help.  Send  to-day  for  free  illustrated 
catalog-.  WIRELESS  TELEGRAPHY  DEPART- 
MENT, GRACELAND  COLLEGE,  Lamoni,  Iowa. 

TYPEWRITERS 

TYPEWRITERS,  all  makes  factory  rebuilt  by 
famous  "Young  Process."  As  good  as  new,  look 
like  new,  wear  like  new,  guaranteed  like  new. 
Our  big  business  permits  lowest  cash  prices.  $10 
and  up.  Also,  machines  rented — or  sold  on  time. 
No  matter  what  your  needs  are  we  can  best  serve 
you.  Write  and  see  now.  Young  Typewriter  Co., 
Dept.  364,  Chicago. 

WIRELESS 

BEFORE  BUILDING  that  receiving  set  get  our 
circular  on  perfectly  designed  switches  and  switch 
points.  Hard  rubber  knobs  used  exclusively. 
Eureka  Secondary  Co.,  6939  S.  May  Street, 
Chicago,  111. 

GET  THEM  WHILE  THEY  LAST 
100  34"  SPARK  COILS,  complete,  $1.40  each. 
200  H"  SPARK  COILS,  without  vibrators,  80c 
each.  50  l'A"  SPARK  COILS,  complete,  each 
$3.25.  Guaranteed.  All  answered.  C.  O.  D. 
terms  accepted.  J.  Eisgran,  1520  St.  Marks  Ave., 
Brooklyn,  New  York. 

LOOK!!  Bargains!  I  have  a  number  of  the 
following  for  sale  or  exchange.  Telephone  Trans- 
mitters, 50c.  Five  bar  magnetos,  75c.  Ford  spark 
coils,  good,  75c;  extra  good,  $1.  Write  for  list. 
Sidney  Collisson,  Keokuk,  Iowa. 

(Continued   on  next  page) 


You  benefit  by  mentioning  "The  Electrical  Experimenter"  when  writing  to  advertisers. 


584 


THE  ELECTRICAL  EXPERIMENTER 


December,  1917 


EL  EC.  SUPPLIES  &  APPLIANCES 


XMAS  GIFTS  FOR  THE  HOME  AND  THE 
BOYS  "AT  THE  FRONT".  Irons,  Toasters, 
Flashlights,  etc.  Nice  things  for  them  all;  high- 
est quality,  the  lowest  prices.  Send  stamp  for 
Special  Xmas  Gift  List  and  prices.  Baer  Electric, 
Van  Wert,  Ohio. 


FOR  SALE!!  100  \y2"  SPARK  COILS,  $3.25 
each.  ISO  H"  SPARK  COILS,  $1.40  each.  Mesco 
12  volt  Dynamo,  $5.  Complete  Tesla  Transformer 
outfit,  comprising  Tesla  Transformer,  ll/2"  coil, 
large  condenser  and  gap,  $9.  All  answered.  J.  C. 
Swimmer,  1904  Park  Place,  Brooklyn,  New  York. 


NEW  Aeroplane  and  Cyclecar  Motors,  $55. 
Send  10c.  for  blue  print.  T.  A.  Eberhardt,  1138 
Wall  St.,  Milwaukee,  Wis. 


FOR  SALE: — New  %  and  1/3  Horse  Power  Al- 
ternating 110  volt  motor;  can  run  from  lamp 
socket,  shipped  from  Chicago  branch  for  Eastern 
trade.  Fully  Guaranteed.  Prices  $22.10  and 
$23.50.    Herbert  Paine,  Box  41-A,  Hayward,  Cal. 


BOYS — A  Splendid  Christmas  Gift.  Just  what 
you  want  to  run  your  Electric  Motors,  Toys,  and 
for  your  experimental  room.  A  75  Watt  Toy 
Transformer  that  generates  6  different  voltages, 
ranging  from  5  to  20  volts  for  $1.85.  Also  special 
Christmas  Tree  Light  Outfits  consisting  of  8  or  16 
lights  for  $1.98  and  $3.85,  equipped  with  Tungsten 
lamps.  Act  quick.  This  is  a  Holiday  Specialty. 
Willard  Meyers,  950  Garfield  Ave.,  Chicago,  111. 


GENERATORS,  32  volt,  for  Farm  Lighting 
Plants.  Also  Switchboards  complete.  GOOD- 
LITE  COMPANY,  INDIANAPOLIS,  IND. 


FOR  SALE— Electric  Motors,  110  volts,  60 
cycle  A.  C,  single  phase,  speed  1750,  lA  H.P.,  $22. 
y2  H.  P.,  $42.  Brand  new,  never  unpacked,  guar- 
anteed perfect.  Lincoln  Supply  Company,  Lin- 
coln, Pa. 

FOR  SALE — Build  your  own  motor  or  generator. 
Can  furnish  new  high  class  4"x3"  armature  with 
set  of  brush  holders  and  six  (6)  brushes  for  $2. 
Can  be  used  for  6  to  12  volts,  shaft  turned  for 
standard  E  17  Norma  ball  bearings  and  threaded 
ys" — 18  thread  for  pulley.     A.  D.  Adams,  422 

Park  Road,  Ambridge,  Pa.  

ELECTRICIANS  and  ARMATURE  WIND- 
ERS. Send  $1.50  for  16  blueprints  of  motor 
windings,  10  A.  C.  single,  two  and  three  phase 
and  6  D.  C.  Or  20  A.  C.  6  D.  C.  and  6  rotary 
converter  drawings  for  $2.25.  Winding  made  easy. 
Superior  Electric  Co.,  Lock  Box  1372,  Pittsburgh, 
Pa. 


Scientific  Exchange  Columns 

UNDOUBTEDLY  you  have  at  the  present  time  some  things  for  which  you  have  no  further  use.  Do  you  wish  to  exchange  them  for  some- 
thing for  which  you  have  immediate  use?  There  is  no  surer  and  quicker  way  to  do  this  than  by  advertising  your  articles  in  these  columns. 
The  Very  people,  the  Only  people,  who  could  possibly  have  a  use  for  your  things  read  this  journal.  More  than  75,000  interested  people 
will  see  your  ad.  It  is  furthermore  the  cheapest  advertising  medium  for  you  in  the  country.  Dealers'  advertising  accepted  in  Opportunity 
Exchange  columns  only. 

The  rates  are:  Five  cents  per  word  (name  and  address  to  be  counted),  minimum  space  3  lines.  Count  about  7  words  to  the  line. 
Remittance  must  accompany  all  orders.    No  advertisement  for  less  than  50c.  accepted. 

We  reserve  to  ourselves  the  right  to  refuse  any  advertisement  which  we  consider  misleading  or  objectionable.  Advertisements  for  the 
January  issue  should  reach  us  not  later  than  November  25th. 

The  Classified  Columns  of  "The  Electrical  Experimenter"  Bring  Positive  Results. 
Subscribers  experiencing  trouble  in  dealing  with  any  advertiser  should  notify  the  publisher  very  promptly. 

OVER  80,000  PEOPLE  READ  THIS  JOURNAL 


WANTED — Aviation  motor;  price  must  be  low. 
Would  consider  a  wrecked  motor.  H.  A.  Mar- 
greiter,  120  E.  Harrison,  Kirksville,  Mo.  

FOR  SALE — Storage  battery,  stamp  collection, 
X-ray  tube,  wireless  and  high  frequency  apparatus. 
Robert  Eccles,  201  Genesee  St.,  Auburn,  N.  Y. 

SACRIFICE  —  Large  magnificent  commercial 
type  radio  cabinet.  Panel  operated.  5,000  miles, 
Yi  K.  W.  Cost  $150,  sell  $80.  Other  things. 
Write  L.  Hamilton,  378  Fairmont  Ave.,  Oakland, 
Cal.  

MOTORCYCLE  ENGINE,  twin  cylinder  com- 
plete with  magneto,  carburetor,  muffler  and  clutch. 
Good  running  condition.  First  $25  takes  it.  Edw. 
J.  French,  Peekskill,  N.  Y.  

NEW  32-inch  $30  Bass  Drum  for  $10.  Also  17- 
inch  $14  Snare  Drum  for  $5.  Clarence  Osborn, 
97  Watkins  Ave.,  Middletown,  N.  Y.  

BARGAIN — I  will  swap  my  large  loose  coupler 
for  a  storage  battery.  Robert  Halverson,  R-l, 
Kasota,  Minn.  

BARGAIN— Two  Meccano  sets  worth  $7.50. 
First  $3.25  gets  both  sets.  Want,  bicycle  motor 
attachment;  Smith  motor-wheel  preferred.  Rus- 
sell  Murrow,  Mitchellville,  Iowa.  

WANTED — Bench  lathe  and  accessories.  State 
size,  make,  condition  and  price.  Also,  what  will 
you  take  in  trade?  W.  Rex  B.  Sutch,  Clayton, 
New  Jersey.  

WILL  SELL — Sturmeyarcher  3  speed  coaster- 
brake  in  wheel,  $6.  54  size  violin,  $5.  Diabolo,  50c; 
Semi-automatic  wireless  key,  $2;  V£"  coil,  $2; 
Punching  bag,  $1.50;  4  magnet  Generator,  $1. 
R.  O.  Miles,  Wyonet.  111.  

WANTED— All  back  numbers  Q  S  T  to  Janu- 
ary 1917.  Sale  or  Exchange — 8,000  meter  un- 
damped coupler,  1600  Navy  coupler  all  taped. 
What  do  you  offer?  Louis  Krieg,  Jr.,  134  No. 
School,  Gloversville,  N.  Y.  

FOR  SALE  CHEAP— 1  6  volt  K  &  D  motor 
No.  5,  $5.50;  8  point  Rheostat,  for  small  motors, 
50c;  Reversing  Switch,  50c;  3  Telephone  Trans- 
mitters, each  75c;  l/2  lb.  No.  36  Enamel  covered 
wire,  $1;  Electric  Whistle,  40c;  "Solar"  6  volt 
70  amp.  Storage  Battery,  $7.50;  3-way  Trans- 
former, 6,  8,  14,  80c;  10  ohm  Magnet,  80c;  80  ft. 
Vi"  square  rubber,  $2.50;  3 lAx5y2  Printing  Frame, 
20c;  1  stick  of  Selenium,  30c;  y2  coil  spring,  new, 
30c;  Two  20  ohm  Standard  Relays,  ea.  $1.25. 
William  J.  Murdock,  322  South  Main  St.,  Clinton, 
Ind.  

WANTED — All  kinds  of  photography  goods. 
Have  some  fine  things  to  exchange.  A.  Hofman, 
382  Cornelia  St.,  Brooklyn,  N.  Y.  

SACRIFICE— Magnificent  Cyclopedia  Applied 
Electricity,  write  enclosing  stamp.  Warnecke,  Jr., 
23  E.  88th,  New  York.  

EXCHANGE  OR  SALE— Superior  Phones,  $4; 
E.  I.  Vario  Selective  Coupler,  $4;  300  ft.  4 
strand  Antenium  Wire,  $2.25;  Two  10^"  Insula- 
tors, 60c;  Four  Sy2"  Insulators,  75c;  Junior  Fixed 
Condenser,  30c.  Above  articles  never  used.  Also 
E.  I.  Commercial  Detector,  75c.  Have  25  Boy's 
books.  Want,  110  volt  motor,  must  be  good  con- 
dition, or  cash.  Write  if  interested.  J.  Raymond 
Stafford,   103   Fisher  St.,   Marquette,  Mich. 

CYCLECAR  material  1  4  H.P.  motorcycle  engine, 
magneto  and  carburetor;  steering  gear  complete; 
front  and  rear  axles;  4  full  eliptical  springs;  2  foot 
levers;  4  wire  spoked  solid  rubber  tired  wheels. 
Sacrifice,  $30,  R.  R.  Crowe,  Box  126,  Baraboo, 
Wis. 


WANT—  y2  to  1  H.P.  500  volt  motor  or  gen- 
erator, Weston  or  Keystone  portable  ammeter  0-50 
amperes,  voltmeter  0-150  volts.  Will  buy  for  cash 
or  exchange  for  radio  apparatus.  Have  an  excel- 
lent Keystone  milliampere  meter;  fine  for  research 
work.  Samuel  Cohen,  1936  Pitkin  Ave.,  Brooklyn, 
N.  Y. 


■■■Ill 

"WANT  TO  SWAP"? 

Do  you  realize  that  these  "Scientific  Ex- 
change Columns"  are  the  World's  most  re- 
nowned "Swap"  market?  "THE  ELEC- 
TRICAL EXPERIMENTER"  prints  80,000 
copies  of  this  issue;  that  means  that  at 
least  160,000  readers  see  this  page  and 
probably  a  great  many  more.  Our  readers 
who  advertise  here  seldom  advertise  the 
same  thing  twice — usually  within  five  days 
after  the  issue  is  out  the  advertised  article 
has  been  sold,  or  swapped.  The  many  testi- 
monials which  we  print  here  from  time  to 
time  are  ample  proof  of  the  almost  mirac- 
ulous pulling  power  of  these  columns. 

Look  around  in  your  attic  or  workshop 
and  you  will  find  dozens  of  long  forgotten 
articles,  useless  to  you  now,  but  very  use- 
ful to  someone  else.  At  a  ridiculously  low 
cost  you  can  either  sell  or  swap  such  articles. 

And  remember  this  fact:  The  U.  S.  Postal 
Laws  protect  you.  No  one  can  "do"  or 
cheat  you.  Of  3,495  "ads"  published  in 
these  columns  during  the  past  five  years, 
only  twelve  complaints  were  reported  to  us, 
and  each  and  every  one  was  adjusted  to 
the  full  satisfaction  of  the  complainant. 

It  matters  not  if  you  have  old  books  or 
magazines,  a  kodak,  electrical  or  chemical 
apparatus,  scientific  instruments,  bicycles, 
typewriters,  moving  picture  machines,  air 
rifles,  watches,  structural  toys,  etc.,  etc. 
All  these  and  countless  others  can  be  speed- 
ily disposed  of  here.  Try  it  and  be  con- 
vinced. 


iiiiiiiiiiiiiii 

329  Elm  St.,  Penn  Yan,  N.  Y. 

Gentlemen: — I  wish  to  tell  you  of  the  successful 
results  I  obtained  from  my  ad  in  the  "E.  E." 
Before  the  publication  date  I  received  an  inquiry 
and  ever  since  they  have  been  "pouring"  in  at 
the  rate  of  several  each  day. 

To  date,  I  have  received  sixty-three  inquiries 
and  have  disposed  of  most  of  articles  advertised. 

Inquiries  have  come  from  as  far  South  as 
Florida,  West  from  Colorado  and  several  from 
Canada. 

Thanking  you  for  your  promptness  in  insert- 
ing my  ad,  and  wishing  a  long  and  prosperous 
"life"  to  the  Electrical  Experimenter,  I  remain 
Yours  truly, 

Lester  Chisholm. 


WANTED — Omnigraph  in  first-class  condition, 
2  inch  spark  coil,  and  guaranteed  2000  or  3000 
mile  receiving  set  complete  with  aerial.  Ivar  Wal- 
lin,  Chignik,  Alaska.  

TWIN  cylinder  motorcycle  engine  in  good  con- 
dition, complete  with  magneto,  carburetor,  clutch 
and  muffler.  $25  takes  it.  Edward  J.  French. 
Peekskill,  N.  Y.  

CHEMICALS— Set  of  fifteen  with  test  tubes, 
alcohol  lamp,  etc.,  for  $1.00.  Electrical  apparatus. 
Drafting  instruments.  25  copies  American  Boy. 
50c.  List  for  stamp.  Lester  Chisholm,  Penn  Yan, 
N.  Y.  

SACRIFICE — y2K.  W.  transmitting  set  com- 
plete. Packard  transformer,  glass  plate  condenser, 
Murdock  O.2.,  Klitzen  rotary  gap  on  marble  base, 
key  on  marble  base.  Everything  good  condition, 
$22.50.    Alex.  Schaff,  R.  R.  11,  Franksville,  Wise. 

FOR  SALE — 4-blade  ceiling  Fan.  1  computing 
scales.  _  Write,  Louis  Elfers,  605  Grandview  Ave., 
Muscatine,  Iowa.  

HUNTING  BARGAINS?  Then  send  sixteen 
dollars  for  my  new  high-class  receiving  outfit  or 
eighteen  dollars  for  my  No.  6  Remington  type- 
writer. Particulars  for  stamp.  Fay  Williams, 
Huron,  Ind.  

REGENATIVE  SET,  including  Audion,  Range 
150-850  meters,  $20.  Want  y2  Kilowatt  trans- 
former, condenser.  McMurdo  Silver,  340  West 
57th  St.,  New  York.    Phone  Columbus  1628. 

BRAND  NEW  DeForest  Round  Amplifier  Bulb, 
$4,  Tubular  Type  $3.  Peerless  Detector,  $1.50. 
Lots  of  bargains,  write.  R.  Cuthbert,  385  E.  184th 
St.,  New  York.  

SELL — Large  Size  Presto-Lite  Tank  with 
brackets,  $9.  Two  cylinder,  four  horse-power  au- 
tomobile steam  engine,  $10.  Clarence  Vaughan, 
Middletown,  N.  Y.  

FOR  SALE— Complete  Wireless  Outfit,  H  K.W. 
Transmitter,  $20.  Printing  Press,  5x8,  10  fonts 
type,  $25.     Typewriter,  $10.     Particulars,  stamp. 

Jensen,  Boscobel,  Wise. 

PRACTICALLY  NEW  I.  C.  S,  Electrical  En- 
gineering,  Electric  Railways  Courses;  two  spark 
coils  7x2'/2,  7'/2x.2  for  $18.  E.  Holmes,  12  Wal- 
nut Park,  Roxbury,  Mass. 

FOR  SALE  OR  EXCHANGE— Set  of  chemi- 
cals and  apparatus  for  twin  cylinder  motorcycle 
engine.  Write  for  particulars.  Robt.  Shank,  521 
So.  Jefferson  St.,  Dayton,  Ohio. 

FOR  SALE — Chemical  Laboratory — Complete 
line  of  chemicals  for  analytical  also  Experimental 
and  Photographic  purposes — Practical  apparatus 
and  Reagent  bottles — Value  $40.  For  particulars 
write  to  N.  H.  Parex,  247  Pearl  St.,  N.  Y. 

EXCHANGE— My  $40  Violetta  complete.  Want 
Omnigraph  in  first-class  condition,  even  exchange, 
or  what  have  you  in  wireless  apparatus?  Geo.  A. 
Chandler,  500  N.  Clark  St.,  Chicago,  111. 

WANTED— Copy  of  book  "Michael  Faraday,  His 
Life  and  Work"  by  Sylvanus  Thompson.  Also  an 
ohmeter  of  the  Roller-Smith  type  or  a  Wheatstone 
bridge;  must  be  in  first-class  condition,  and  include 
galvanometer.  H.  W.  Secor,  c/o  Electrical  Ex- 
perimenter, 233  Fulton  St.,  New  York  City. 


Ypii  benefit  by  mentioning  "The  Electrical  Experimenter"  when  writing  to  advertisers. 


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and  a  reference  guide  in  one,  written  in  plain  every  day  language — no  wasted  words 
— only  what  you  need  to  know — chock  full  of  up-to-the-minute  electrical  knowledge. 
The  guides  are  a  complete  course  in  electrical  engineering.  They  will  help  you  in 
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and  4.700  illustrations.  Once  you  see  these  hooks  and 
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Geo.  Knecht,  Columbus,  Ohio. 

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to  me  in  the  Naval  Electrical  Depart- 
ment, which  they  cover  very  thorough- 
ly." C.  J.  Cornell. 
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No 


READ  THIS  PARTIAL  LIST  OF  CONTENTS 

|  Contains  348  pages.  388  illustrations.  Electrical 
signs  and  symbols — static  and  current  electricity 
— primary  cells — conductors  and  Insulators — resistance  and 
conductivity — magnetism — induction  coils — dynamo  principles 
-classes  of  dynamos — armatures — windings — commutation — 
brushes,  etc.  \ 
No  2  Contains  3-18  pages.  394  illustrations.  Motor 
principles — armature  reaction — motor  starting — 
calculations — brake  horsepower — selection  and  installation  of 
dynamo  and  motors — galvanometers — standard  cells — current 
measurement  —  resistance  measurement  —  voltmeters  —  watt- 
meters— watt  hour  meters — operation  of  dynamos — operation 
of  motors,  etc. 

No.  3  Con,ail»  3ni>  Pases.  423  illustrations.  Distribution 
«  j  systems— wires  and  wire  calculations — inside,  out- 
tiUfL.  ""jerground  wiring— sign  flashers— lightning  pro- 
tection—rectifiers— storage  battery  systems,  etc. 
No.  4  r°ntai"s  27"  Pages.  379  illustrations.  Alternating 
the  ^„^Urrten!  Pr"',ciPles— alternating  current  diagrams 
7r,V„.i„P  •  i.ai'tor— alternator  principles— alternator  con- 
struction— windmgs,  etc. 

No.  5  Co""'rs  320  Ml«».  814  illustrations.  A.  O  Motors 
coniniutator^oTnr»?^S^dinductionmotnrr'rin,:iPles— A-C. 
conduction  m°'"rs— '."duction  motors,  transformers:  losses, 
construction  connections,  tests-converters-rectifiers,  etc. 
NO.  6  ™J^?a  29.g  pa(;e9-  472  illustrations.  Alternating 
ers— relavs-n1.htn^nSJStem.3~3mtchin,:  devices— circuit  break 
-svnchronoT.  "^£f*5  P™*"*0!,  annaratus-regulatlne  devices 
factor  ind  c^ors  w»vfr^,,n<llea,,ni;  devices-meters-power 
i«™r  indicators— wave  form  measurement— switch  boards,  etc 

NO.   7    ^"'"'{"l1?  379  illustrations.  Alternating 

"tent  selection  ?o;.»M  lng  PTer  stat  ons-turbines :  manage- 
reoalr-Te^phone,  "etc    '  ereCt'°n'  t68t,ng-  rUnnin*'  rare  a"d 

No.  9  SffiHaysae^taS  A 

starters  and  lirtMni-  sV^teml'mIwT'autem?DUe  s<?'f"  A 

No.  io  skSSt183"^*  t 

soldering   and   brazlng-indusfr afeh       * ~  THEO. 
-xVays  etc  P'a«'"^«etro-theranV»« - 
Also  a  complete  126-page  readv  * 

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The  Only  Way  to  Learn 
Elect!  icity 

The  only  way  you  can  become  an  ex- 
pert is  by  doing  the  very  work  under  com- 
petent instructors,  which  you  will  be  called 
upon  to  do  later  on.  In  other  words,  learn 
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York  Electrical  School. 

Five  minutes  of  actual  practice  properly 
directed  is  worth  more  to  a  man  than  years 
and  years  of  book  study.  Indeed,  Actual 
Practice  is  the  only  training  of  value,  and 
graduates  of  New  York  Electrical  School 


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demand  cf  the  Electrical  Profession. 

At  this  "Learn  by  Doing"  School  a  man 
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using  electricity.  A  school  for  Old  and 
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for  vourself  in  the  electrical  field  you  will 


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/  Q 


ELECTRICAL  NEWS  ILLUSTRATED 


ELECTRO  -  MAGNETI C 
DEPTH-BOMBS 


SEE  PAGE  594 


This  is  the  Electrical  Age,  and  this  wonderful  new  profession  is  calling  you.  The 
demand  for  expert  Electricians  is  greater  every  year  and  the  salaries  higher.  Elec- 
tricity is  truly  the  greatest  motive  power  in  the  world,  to-day,  and  now  is  the  time  to 
enter  this  profession. 


YOU  CAN  DO  THIS' 


i 

6'%.. 


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ELECTRICAL  EXPERIMENTER 


January,  1918 


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Address . 


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Electrical  E^perimeimter 

233  FULTON  STREET,  NEW  YORK 

Publisht  by  Experimenter  Publishing  Company,  Inc.  (H.  Gernsback,  President;  S.  Gernsback,  Treasurer;)   233  Fulton  Street,  New  York 


Vol.  V     Whole  No.  57 


JANUARY,  1918 


No.  9 


ELECTRO-MAGNETIC     DEPTH     BOMBS     DESTROY  SUBMA- 
RINES  Front  Cover 

From  a  Painting  by  George  Wall 
ARE  THE  "HUNS"  USING  ELECTRIC  RAIDERS? 

By  H    Winfield  Secor 

FOG  WARNING  BY  RADIOPHONE  By  George  Holmes 

GROUND  TELEGRAPHY  IN  WAR  Bv  H.  Gernsback 

HOW  AURORA  BOREALIS  AFFECTS  TELEGRAPH  AND  CABLE 

LINES   

THE  ELECTRO  MAGNETIC  DEPTH  BOMB— TERROR  OF  THE 

"SUBS"  

ELECTRIC  BUOYS  TO  MARK  TORPEDOED  SHIPS, 

r*v  E   T    Tones,  U.S.N. 

TRAINING  U.  S    A VTATORS  WITH  ELECTRIC  MAP   596 

LIBERTY  LOAN  ELECTRIC  SIGNS   597 

BRONZE  TABLET   TO   MARK   FIRST   EDISON    STATION  IN 

NEW  YORK    598 

THE  X  RAY  ON  THE  BATTLE-FRONT   599 

HOW  A  GERMAN  TELEPHONE  OUTPOST  LOOKS   600 

"TERATUTF.R" — AN     ELECTRICALLY     OPERATED  FLYING 

TEACHER   601 

MODERN  PHYSICS  AND  THE  ELECTRON     THE  WORK  OF 

PROF.  MILLIKAN    602 

NOVEL  APPLICATIONS  OF  THE  DICTOGRAPH   605 

THE  CHEMICAL  EXHIBITION  AT  NEW  YORK, 

Bv  Albert  W   Wilsdon  608 


589 
591 
592 

593 

594 

595 


WAR   ADDRESS   BY   A.    I.    E.   E.    PRESIDENT-ELECT   E.  W. 

RICE,  JR   609 

"TOO  LATE''— THE  STORY    OF  A  SUCCESSFUL  RELAY  THAT 

WAS  UNSUCCESSFUL  By  Charles  S.  Wolfe  610 

"ELECTRICIAN  RADIO,  U.  S.  N."— THE  WORK  OF  THE  NAVAL 
RADIO  SCHOOL, 

Bv  Willard  Connely,  Chief  Yeoman,  U.   S.  N.   R.  F.  612 

FRENCH  AEROPLANE  RADIO  GREAT  AID  TO  ARTILLERY   614 

A  SHORT-CUT  TO  CODE-LEARNING  By  Thomas  Reed  615 

"HAM"  AERIALS  By  W.  J.  Howell  616 

A  MECHANICAL  INDUCTANCE  CHANGER, 

By  Frederick  J.  Schlink  617 

TESTING  OF  DYNAMOS  AND  MOTORS  By  Samuel  Cohen  619 

EXPERIMENTAL  MECHANICS.    LESSON  I  Bv  Samuel  Cohen  620 

A  NEW  TYPE  OF  CHROMIC  ACID  BATTERY.. By  C.  A.  Oldroyd  622 
THE  ULTRA -MICROSCOPE  AND  THE  UNDERWORLD  OF  IN- 
FINITESIMAL SMALL  By  Frank  M.  Gentry  623 

HOW  TO  MAKE  IT  DEPT.— PRIZE  CONTEST   624 

WRINKLES.  RECIPES  AND  FORMULAS.  .  Edited  by  S.  Gernsback  625 
EXPERIMENTAL   CHEMISTRY— 20th  Lesson, 

By  Albert  W.  Wilsdon  626 

"ELECTRICAL   LABORATORY"— Prize  Contest   627 

LATEST  PATENTS  DIGEST    628 

PHONEY  PATENTS— CONTEST    629 

OUESTION  BOX    630 


Raising  Sunken  Treasures 


VER  since  the  Phoenicians  set  sail  upon 
the  Mediterranean,  man's  imagination  has 
been  stirred  profoundly  at  the  idea  of  re- 
covering priceless  cargoes  resting  at  the 
bottom  of  the  ocean.  Whether  it  is  Cap- 
tain Kidd's  fabled  treasure  or  the  real 
$10,000,000  gold  treasure  sunk  at  Vigo 
in  1702  and  now  peacefully  resting,  not  far  from 
the  Spanish  coast,  makes  little  difference.  All  of 
us  nurse  a  secret  desire,  that  somehow,  some  day  we 
will  be  in  a  position  to  raise  one  of  the  many  sunken 
treasures.  If  ever  mankind  was  interested  in  salvaging 
the  cargoes  of  sunken  vessels,  the  first  few  years  after 
the  present  World  War  is  over,  will  surely  eclipse  any- 
thing of  the  kind  ever  imagined  before.  Billions  of 
dollars  worth  of  priceless  cargoes  now  stud  the  bottom 
of  the  oceans,  and  while  many  of  the  torpedoed  ships 
contain  perishable  cargoes,  not  worth  raising,  there  are 
just  as  many  ships  and  perhaps  a  great  many  more  that 
contain  valuable  cargoes  of  metals,  coal,  ore,  etc.,  which 
are  not  at  all  affected  by  a  prolonged  stay  in  salt  water. 
These  ships  then  are  worth  while  raising — if  they  can 
be  located — in  order  to  salvage  their  treasures. 

Several  companies  have  already  been  formed  in  this 
country  (and  we  understand  in  Germany  too)  whose 
sole  business  it  will  be  to  sail  the  high  seas  in  quest  of 
sunken  treasures,  immediately  after  peace  is  declared. 

Now  comes  an  interesting  point :  The  oceans,  be- 
yond the  three  mile  limit  belongs  to  no  nation.  By 
ancient  custom  a  ship  sunk  in  the  onen  sea  belongs  to 
whoever  salvages  it.  Neither  the  original  owner,  nor 
the  insurance  company  who  paid  for  the  loss,  has  any 
claim  on  the  sunken  ship.  Will  this  ancient  custom 
prevail  after  the  present  war?  We  much  doubt  it. 
Great  Britain,  the  greatest  loser  of  ships  and  treasure 
during  the  war,  may  be  counted  upon  to  propose  a  new 
international  law,  whereby  the  sunken  ship  no  matter 
where  lost,  will  revert  to  the  original  owners,  after  the 
latter  have  paid  a  premium  for  the  expenses  incidental 
to  salvaging  the  hull.  The  British  at  the  end  of  the  war 
will  have  several  billions  worth  of  treasure  on  the  bot- 
tom of  the  ocean.  We  may  be  sure  tjiat  they  will  make 
a  Herculean  effort  to  salvage  whatever  cargo  can  be 
raised  economically. 


Now  the  curious  part  about  this  is  that  the  very  sub- 
marine which  was  the  direct  cause  that  occasioned  the 
loss  of  all  these  ships,  will  prove  to  be  the  one — and 
perhaps  the  only  one — instrumentality  to  salvage  these 
same  ships. 

Already  we  can  picture  in  our  mind's  eye  flotillas  of 
specially  constructed  submarines,  which  will  roam  thru 
the  inky  depths  of  the  seven  seas.  For  there  is  no 
technical  difficulty  today  to  build  a  submarine  capable 
of  withstanding  the  tremendous  water  pressure  even 
at  a  depth  of  one  thousand  feet.  And  it  is  safe  to  say 
that  the  majority  of  ships  rest  at  a  considerably  lesser 
level.  But  how  to  find  the  sunken  ships?  That  is  the 
question.  Nevertheless  the  problem  is  not  half  as 
difficult  as  it  may  appear  at  first.  Science  progresses 
fast,  and  it  has  a  trick  of  making  today's  impossible, 
tomorrow's  commonplace. 

A  deep-sea  submarine  equipt  with  very  powerful 
searchlights  can  exploit  the  bottom  of  the  ocean  with- 
out any  trouble  whatsoever.  Each  such  submarine  ex- 
ploits a  certain  square  of  territory  and  it  will  be  but  a 
few  weeks  till  every  such  area  is  charted.  Undersea 
growth  or  sea  mud  or  drift  sand  will  not  be  much  of 
an  obstacle,  even  if  a  ship  is  totally  hidden  from  view. 
For  the  exploring  submarines  will  be  equipt  with  sensi- 
tive electric  Hughes  Balances,  which  indicate  at  once 
the  presence  of  metal  masses.  Incidentally  such  elec- 
tric explorations  will  surely  be  the  direct  means  of  dis- 
covering sub-oceanic  ore  deposits  which  in  the  near 
future  will  certainly  be  exploited  by  sinking  down  cais- 
sons over  the  under-water  mine.  A  similar  method  by 
the  way,  is  already  in  use  near  the  coast  of  California 
where  oil  is  taken  out  of  sub-aquatic  oil-wells. 

Once  the  wrecking  submarine  has  located  the  sunken 
ship,  it  is  a  comparatively  simple  matter  to  raise  it. 
Great  steel  tanks  are  sunk  about  the  ship,  which  are 
then  made  fast  to  the  latter  by  well-known  methods. 
A  wrecking  steamer  from  above  now  forces  comprest 
air  into  the  tanks  which  blow  out  the  water  in  the  latter. 
Providing  we  have  sufficient  tanks,  the  resultant  buoy- 
ancy will  raise  any  ship  to  the  surface  of  the  ocean, 
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H.  Gernsback. 


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ELECTRICAL  EXPERIMENTER 


January,   1  9  1 


The  Only  Way  to  Learn 
Electricity 

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petent instructors,  which  you  will  be  called 
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New  York  Electrical  School. 

Five  minutes  of  actual  practice  properly 
directed  is  worth  more  to  a  man  than 
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ELECTRICAL 
EXPERIMENTER 


H.  GERN5B&CK  editor 

H.  W.  5ECPR  rt55t7C1&TE  EDITOR 


Vol.  V.    Whole  No.  57 


January,  1918 


Number  9 


Are  the  "Huns"  Using  Electric  Raiders? 


IT  is  stated  in  recent  press  reports,  one 
of  which  professes  to  be  an  English 
Admiralty   statement,   that  the  Ger- 
mans have  put  into  commission  a  re- 
markable  new   war-vessel  controlled 
from  shore  by  means  of  an  electric  cable 
attached  to  the  boat,  and  which  craft  is 
crew-less. 

The  report  in  question  further  says  that 
— "the  electrically  controlled  motor  boats 
used  on  the  Belgian  Coast  are  twin  petrol 
engine  vessels,  partly  closed  in,  and  travel 


By  H.  WINFIELD  SECOR 

Vernon,  a  torpedo  experimental  ship,  as 
far  back  as  1885.  The  only  new  features 
in  the  German  boat  are  the  petrol  engines 
and  wireless  signals,  neither  of  which  ex- 
isted then." 

So  much  for  the  press  descriptions.  But 
is  such  a  craft  practical?  How  is  it  possi- 
ble to  maneuver  such  a  strange  acting 
vessel ;  for  strange  it  certainly  would  be, 
for  hailing  signals  could  not  be  answered 
with  no  crew  on  board;  without  the  enemy 
vessels    opening    lire    and    destroying  it? 


in  a  compartment  well  below  the  water-line, 
it  would  appear  to  be  possible  for  the 
"raider"  to  undergo  quite  a  little  shelling 
without  being  blown  up,  and  if  such  was 
the  case,  the  "raider"  might  eventually 
reach  her  objective. 

However,  there  is  another  very  promis- 
ing side  to  the  question.  Low  visibility — 
in  other  words,  foggy  or  partly  foggy 
weather.  Here  is  where  the  "electric  raider" 
shines.  The  seaplane  would,  of  course,  be 
the    all-important    means    whereby,  the 


ri^pi  i  1917  J 


It  Is  Reported  That  the  Germans  Recently  Sprung  a  Surprise  on  the  Allied  Fleet  Off  the  Belgian  Coast  in  the  Form  of  An  Electrically  Con- 
trolled "Man-less"  Boat,  Loaded  With  High  Explosives.    The  Idea  Seems  Feasible — and  Why  Not  Use  a  Submarine  in  the  Same  Way?  The 
Seaplane  Reports  the  Boat's  Movements  Back  to  Shore  Where  the  Control  Apparatus  Connects  With  a  Cable  Joined  to  the  Boat. 


at  a  high  rate  of  speed.  They  carry  a  drum 
with  between  thirty  and  fifty  miles  of  insu- 
lated single  core  cable,  thru  which  the  boat 
is  controlled  electrically.  The  forepart  car- 
ries a  considerable  charge  of  high  explo- 
sive, probably  from  300  to  500  pounds  in 
weight. 

"The  method  of  operating  is  to  start  the 
engine,  after  which  the  crew  leave  the  boat. 
A  seaplane,  protected  by  a  strong  fighting 
patrol,  then  accompanies  the  vessel  at  a 
distance  of  from  three  to  five  miles  and 
signals  to  the  shore  operator  of  the  helm. 
These  signals  need  only  be  'Starboard,' 
'Port'  or  'Steady.'  The  boat  is  zigzagged 
while  being  steered  into  a  ship  and  the 
charge  explodes  automatically. 

"The  device  is  a  very  old  one.  A  boat 
quite  similarly  controlled  was  the  H.  M.  S. 


Again,  is  it  possible  for  such  an  engine  of 
war  to  be  made  with  a  range  of  50  miles — 
or  even  10  miles?  After  considering  the 
above  and  numerous  other  questions,  it 
seems  that  it  would  be  quite  possible  and, 
under  certain  favorable  conditions,  dis- 
tinctly practical,  for  the  following  reasons : 
In  the  first  place,  it  seems  rather  prob- 
lematical whether  or  not  the  "electric 
raider"  could  approach  the  enemy  vessels 
close  enough  to  do  any  serious  damage, 
when  the  weather  is  clear.  This  seeming 
disadvantage  might  be  overcome,  however, 
by  the  utilization  of  reserve  engine  power 
on  the  "raider"  when  she  had  approached 
her  target,  permitting  her  to  descend  on  the 
ship  at  a  speed  of  40  to  50  miles  per  hour. 
By  suitably  disposing  the  magazine  con- 
taining the  500  pounds  of  high  explosive 


raider  could  be  maneuvered  in  any  case. 
With  foggy  weather  to  help,  the  location 
and  movements  of  the  craft  could  at  all 
times  be  ascertained  by  attaching  a  kite  to 
it,  which  the  aviator  could  see  above  the 
fog  layer,  or  a  light,  extra  high  mast  could 
be  provided.  In  this  way,  and  by  other 
means,  such  as  by  arranging  a  radio  trans- 
mitter on  the  raider,  it  would  be  quite 
practical  indeed  to  operate  such  a  boat. 

Another  interesting  problem  concerns  the 
50  miles  of  cable,  which  is  presumably  car- 
ried on  a  reel  on  the  boat,  the  cable  being 
anchored  on  shore  and  properly  connected 
up  to  the  necessary  control  instruments. 
Here  also  is  a  radio  station  to  receive  the 
instructions  sent  by  the  seaplane  watching 
the  progress  of  the  "raider."  With  regard 
to  the  great  length  of  cable  mentioned,  this 


589 


590 


ELECTRICAL  EXPERIMENTER 


January,  1918 


Artillery  Telephone  Service  on  British  Front 


THE  telephone  has  solved  thousands  of 
complex  problems  in  the  great  conflict 
across  the  ocean,  as  we  well  know  to- 
day. However,  it  is  not  often  that  we 
read  very  much  or  see  photographs  of  mili- 
tary telephone  sta- 
tions located  but  a 
short  distance  from 
the  firing  line,  es- 
pecially those  in 
active  use_  by  the 
artillery  units. 

The  accompanying 
photograph  is  there- 
fore of  supreme  in- 
terest in  that  the 
grim-looking  "Tom- 
mies" in  their  steel 
helmets  seen  tele- 
phoning orders,  are 
actually  located  in  a 
concrete  dug-out  but 
five  hundred  yards 
from  the  "Boches." 

The  brave  British- 
ers here  shown  are 
telephoning  orders 
from  the  observa- 
tion officers  to  the 
men  behind  the  guns 
of  an  adjoining  artil- 
lery unit,  and  alter- 
ing the  range  figures 
as  they  are  given  to 
them  by  the  ob- 
servers. 

These  underground 
dug-outs,  such  as  the 
one  here  shown  oc- 
cupied by  a  Signal 
Corps  squad,  are  al- 
ways built  with  the 

idea  in  mind  to  make  them  as  nearly  bomb 
and  shell-proof  as  possible,  but  with  the 
large  size  shells  now  in  use,  it  is  not  un- 
usual for  these  massive  projectiles  to 
pierce  the  roof  of  a  "bomb-proof"  and 


destroy  it.  Such  work  as  this,  of  course, 
all  comes  in  the  day's  work  of  the  soldier. 

Not  only  does  it  require  men  of  stout 
heart  and  excellent  physique,  not  to  men- 
tion the  best  of  nerves,  for  such  operations 


A  Recent  British  Photograph  Which  Is  Remarkable  In  That  it  Shows 
Out  Within  500  Yards  of  the  Boches.    These  "Tommies"  Are  Under  Fi 
the  Orders  For  Altering  the  Gun  Range. 

when  under  fire,  but  equally  as  dangerous 
and  even  more  so  in  many  cases  is  the 
work  of  the  telephone  and  telegraph  line- 
men attached  to  the  Signal  Corps  division 
of  the  army,  who  may  be  ordered  to  com- 


plete a  circuit  suddenly  opened  by  a  stray 
shell.  When  an  advance  is  made,  no  mat- 
ter whether  it  is  large  or  small  in  magni- 
tude, the  Signal  Corps  men  will  always  be 
found  right  on  the  job,  stringing  their 
communication  lines 
from  shell  -  hole  to 
shell-hole,  thru  for- 
ests and  across  rivers. 

Without  a  word 
these  men,  clutching 
up  their  rifles  and 
tools,  may  have  to 
pass  out  .  into  the 
white  light  of  the 
German  star-shells  at 
night.  More  danger- 
ous shells  may  be 
falling  with  monoton- 
ous regularity  as  they 
go  forward.  Such 
happenings  go  un- 
heeded. At  length 
they  reach  a  shell- 
hole,  the  cause  of 
their  unwisht  for 
promenade.  If  the 
telephone  line  has 
been  broken  by  a 
shell,  the  work  of 
splicing  a  new  piece 
of  wire  to  the  broken 
ends  in  soon  accom- 
plisht.  They  then  re- 
trace their  steps  to 
the  dug-out. 

When  a  hostile 
trench  is  about  to  be 
taken,  the  telephone 
operators,  in  accord- 
ance with  orders, 
wait  until  their  com- 
rades have  taken  the  enemy  position.  The 
attacking  forces  have  scarcely  reached 
thei^  objective  before  the  telephone  line- 
men are  doubling  across  "No  Man's  Land," 
in  order  to  establish  their  lines. 


BrtUsh  Official  War  Photos 

a  Telephone  Dug- 
re  and  Telephoning 


(Continued  from  page  589) 
presents  no  unusual  difficulty,  this  for  the 
reason  that  the  cable  need  only  carry  a 
single  pole  current,  the  return  circuit  being 
thru  the  water.  A  special  step-by-step 
relay  or  other  selective  device  on  the  vessel 
can  serve  to  control  several  functions,  by 
sending  different  impulses  over  the  cable. 
At  the  proper  time  the  detonating  impulse 
would  be  sent  thru  the  cable. 

But  granting  all  these  things — the  author 
would  suggest — why  not  use  an  electrically 
controlled  submarine?  The  idea  is  not  new, 
as  the  Edison-Sims  electric  cable-control- 
led torpedo  bears  witness,  not  to  mention 
several  other  attempts  in  this  direction. 
The  electrically  controlled  "sub,"  guided  by 
a  seaplane,  which  would  "radio"  back  to 
shore  its  various  movements,  would  seem 
to  be  a  powerful  weapon  under  conditions 
where  it  could  be  employed.  According  to 
the  latest  data  an  aviator  can  see  a  "sub" 
when  it  is  submerged  100  feet  under  the 
water.  There  would  thus  seem  to  be  a 
good  chance  of  applying  this  scheme.  Old 
submarines  could  be  used  for  such  opera- 
tions. 

The  author  has  ascertained  that  several 
well-known  engineers  hold  ideas  similar  to 
the  above,  concerning  the  feasibility  of  the 


"electric  raider,"  including  Mr.  Christian 
Berger,  inventor  of  the  submarine  wire- 
less signaling  scheme  now  used  by  all  sub- 
marines. 

There  has  been  much  talk  of  late  of 
various  fanciful  and  gigantic  schemes  for 
forcing  a  way  thru  the  Heligoland  defenses, 
and  other  heavily  mined  and  fortified  ap- 
proaches, harbors  and  channels.  Mr.  Arthur 
Bennington,  of  New  York,  a  keen  observer 
of  all  war-time  maneuvers  and  inventions, 
recently  told  the  writer  that  he  thought 
this  "electric  raider"  game  seemed  to  hold 
forth  great  promise  indeed,  for  just  such 
gigantic  operations. 

"Let  us  take  a  veritable  fleet  of  old  sub- 
marines and  other  nondescript  vessels,  and 
fit  them  with  electric  control  cables,  en- 
gines or  motors,  etc."  said  Mr.  Bennington. 
"Load  them  up  with  high  explosives  and 
get  everything  in  readiness.  Have  the  Al- 
lies' battle  fleet  ready  for  business — Then 
start  the  first  electric  boats  thru  the  mine 
fields.  Every  time  a  boat  is  blown  up,  an 
ever-increasing  swath  will  be  cut  thru  the 
mine  field,  and,  woe  be  to  the  U-boat  that 
tries  to  pass  thru  the  zone  under  attack. 
It  looks  really  very  feasible  to  carry  out 
just  such  an  operation  as  this,  with  the 
result  that  before  long  the  Allied  battle 


fleet  would  be  able  to  reach  the  German 
sea  defenses  and  readily  destroy  them." 


WHAT  MARCONI  DREW. 

Mrs.  Alec  Tweedie's  entertaining  book 
dealing  with  her  wonderful  collection  of 
autographed  tablecloths — a  hobby  of  hers — 
contains  the  following: 

"Among  the  little  drawings  on  one  of  the 
cloths,"  writes  the  authoress,  "is  a  telegraph 
pole  from  which  hangs  a  broken  wire. 

"Can  you  guess  who  drew  it?  The  artist 
was  sitting  beside  me  when  I  begged  for 
something  more  than  a  name.  He  quietly 
replied : 

"  'Well,  I  can  draw  a  little,  if  I  have 
time.' 

"  'You  shall  have  all  the  time  you  want,' 
I  suggested.  'We  can  keep  the  dessert  wait- 
ing.' 

"  'No,  no,  I'll  try  to  be  quick.  Would  a 
telegraph  pole  do?' 

"  'Certainly,  tho  it  will  hardly  be  emble- 
matic of  your  work.' 

"  'Yes,  it  will,'  rejoined  my  guest,  'for  I 
can  break  the  wire.' " 

Needless  to  add,  the  guest  in  question  was 
Signor  Marconi,  the  inventor  of  wireless 
telegraphy. 


BACK  NUMBERS  I — Many  readers  desire  to  obtain  back  numbers  of  this  Journal.  We  have  a  limited  quantity  of  these  back  Issues  on 
hand  and  can  supply  them  at  the  following  rates:— Back  numbers  of  The-  Electrical  Experimenter  not  over  -three  months  old,  15  cents 
each;  over  three  months  old,  20  cents  each;  over  one  year  old,  35  cents  each. 


January,  1918 


ELECTRICAL  EXPERIMENTER 


591 


Fog  Warning  by  Radiophone 


WHETHER  for  business  or  pleasure 
there  is  not  one  of  us  who  would 
not  enjoy  an  ocean  trip  to  chase 
away    our    cares    and  worries. 
Those  of  us  fortunate  to  share 
such  a  luxury  certainly  enjoy  the  bright 
sunny  decks,  the  beautiful  skies  and  the 
fine  sea  air. 

This  is  only  one  side  tho  for  there  are 
often  days  and  nights,  even  weeks  when 
storms  are  raging  or  heavy  misty  fogs  set 
in,  wherefore  it  becomes  necessary  for  the 
passengers  to  amuse  themselves  indoors,  in 
the  salon,  at  the  piano  or  in  the  smoking 
room  swapping  stories  arid  playing  cards. 


By  GEORGE  HOLMES 

ship,  passengers  travel  with  a  really 
wonderful  sense  of  safety  compared  to  the 
olden  days. 

Lately  a  very  important  development  in 
the  line  of  radio  has  come  to  the  aid  of  the 
lighthouse  crews  to  assist  in  warning  ships 
of  dangerous  shoals  and  rocks.  We  are 
indebted  to  the  well-known  radio  inventor 
Dr.  Lee  de  Forest,  for  this  latest  applica- 
tion of  Radio.  A  short  official  description 
is  given  in  a  recent  Hydrographic  Bulletin 
issued  by  the  U.  S.  Naval  Hycjrographic 
Office. 

The  first  real  test  of  this  apparatus  is 
now  taking  place  at  Point  Judith  Light 


regulating  it;  also  connecting  posts  for 
aerial  and  ground  wires.  On  the  side  of  the 
cabinet  is  a  small  door  which  gives  access 
to  the  mechanism  inside. 

All  the  working  parts  are  mounted  inside 
the  cabinet,  including  a  motor-driven  phono- 
graph speaking  directly  into  , a  microphone. 
The  arrangement  of  the  cylindrical  records 
is  such  that  they  repeat  automatically,  the 
saffire  needle  being  set  back  to  the  begin- 
ning each  time  after  it  has  traveled  the 
length  of  the  record.  Each  record  has  an 
average  life  of  about  60,000  repetitions. 

The  fundamental  idea  of  this  method  of 
radiating  fog  warning  signals,  by  varying 


The  U.  S.  Government  Is  Now  Trying  Out  the  New  de  Forest  Radiophone  Fog  Warning  Device  Here  Illustrated.  By  This  System  of  Warn- 
ings It  Is  Possible  to  Radiate  Either  Wireless  Telephone  Signals  or  Acoustic  Signals,  the  Latter  Being  Reproduced  From  a  Phonograph, 
Amplified  With  Audions,  and  Propagated  Thru  the  Air  From  the  Regular  Fog  Siren  Horns  as  Shown.     Each  Warning  Extends  For  a 

Certain  Predetermined  Range. 


And — Oh,  yes,  .  .  .  leaning  over  the  rail 
for  "enlightment"  ? 

At  such  times  as  these  the  grizzled 
sea  captain  must  worry,  for  on  him  rests 
the  responsibility  of  bringing  his  ship  and 
passengers  safely  thru  the  storm. 

Of  recent  years,  inventors  have  con- 
stantly sought  to  make  navigation  less 
hazardous  and  each  year  sees  new  improve- 
ments along  these  lines.  What  with  sub- 
marine signals,  automatic  engine-room 
signals,  searchlights  and  wireless  to  keep 
in  touch  with  the  world  and  safeguard  the 


(near  Narragansett  Pier)  and  is  arranged 
on  a  very  compact  scale  so  that  it  can  be 
attended  to  by  the  regular  lighthouse  keeper 
and  assistant.  A  regulation  gasoline  engine 
connected  with  a  36  volt  direct-current  gen- 
erator and  storage  batteries  is  used  to  sup- 
ply the  energy,  to  which  is  coupled  a  motor- 
generator  set  which  operates  the  transmit- 
ting apparatus. 

This  apparatus  is  entirely  enclosed  in  a 
very  small  cabinet  measuring  but  18x18x18 
inches.  On  the  front  of  the  cabinet  is  the 
Oscillion  bulb  and  necessary  switches  for 


quantity  with  ranges  or  power,  was  covered 
in  a  U.  S.  patent  issued  to  Dr.  de  Forest 
in  1916,  number  1,183,802,  on  an  application 
filed  in  1908. 

In  the  circuit  diagram  may  be  seen  the 
relative  layout  of  the  various  horns, 
microphones,  and  the  commutator  arrange- 
ment which  permits  the  proper  sentence  to 
be  sent  in  its  turn. 

Several  other  modifications  of  the  under- 
lying principles  may  also  be  utilized  as 

(Continued  on  page  645) 


592  ELECTRICAL  EXPERIMENTER  January,  1918 

Ground  Telegraphy  in  War 


WHEN  trench  warfare  first  became 
an  accepted  fact  it  became  of 
vital  importance  that  the  front 
trenches  should  be  in  permanent 
communication  at  all  times  with 
the  supporting  trenches,  as  well  as  the  gen- 
eral command  behind  the  lines.    At  first 


By  H.  GERNSBACK 

it  becomes  more  or  less  an  easy  matter  to 
shell  these,  and  for  that  reason  during  the 
past  year  or  so,  the  French  have  found  it 
advantageous  to  do  away  entirely  with 
metallic  lines,  running  from  the  front  to 
the  supporting  trenches,  and  thence  rear- 
ward. 


Ground  telegraphy  as  its  name  implies, 
means  sending  impulses  thru  the  earth 
without  the  use  of  intervening  wires.  The 
simplest  system  of  this  kind  is  shown  in 
the  annexed  sketch  where  A  and  B  are 
two  metallic  spikes  driven  into  the  ground, 
these  spikes  being  connected  with  a  bat- 


A  New  "Wireless"  Communication  Scheme  Is  Now  Being  Used  In  the  French  Front  Line  Trenches.  This  Is  Nothing  More  Nor  Less  Than 
"Ground  Telegraphy"  in  a  New  Dress.    By  Using  Specially  Tu"»h  Transmitters  and  Screens,  Interference  By  the  Enemy  Is  Practically 

Eliminated. 


nothing  but  regular  telegraph  lines  were 
laid,  either  at  the  bottom  of  the  communica- 
tion trenches,  or  otherwise  the  wires  were 
suspended  by  some  form  of  insulator. 
Such  lines  were  not  in  all  cases  permanent, 
but  served  the  purpose,  as  none  of  the 
wires  were  intended  to  stay  up  forever  but 
were  changed  around  more  or  less  due  to 
varying  war  conditions. 

Trenches  under  fire  make  it  impossible 
to  maintain  unbroken  cable  or 
wire  lines,  and  it  goes  without 
saying  that  such  lines  are  severed 
with  annoying  frequency  by  shell 
shots,  bombs  or  surprise  raid- 
ing parties.  After  the  enemy 
has  raided  a  trench,  and  the  lat- 
ter is  taken  away  from  him  sub- 
sequently, there  is  not  much  left 
of  the  cables  or  telegraph  lines, 
and  they  must  be  replaced  im- 
mediately in  order  to  keep  up 
the  communications  with  the 
rear.  Particularly  when  trenches 
were  being  shelled  in  the  past, 
it  became  a  ticklish  proposition 
to  keep  the  lines  open,  as  it  is 
always  the  business  of  the  enemy 
to  search  out  the  communication 
trenches  with  a  view  of  disrupting  the 
telegraph  lines,  which  in  such  cases  are 
nearly  always  hit. 

The  communication  trenches  being  neces- 
sarily at  right  angles  to  the  enem/s  lines, 


It  has"  been  the  writer's  good  fortune 
recently  to  interview  a  French  "T.  S.  F." 
"Telegraphie  Sans  Fil"  officer  (Wireless 
Telegraph  Corps)  and  the  officer  in 
question  has  been  kind  enough  to  give  us 
interesting  particulars  as  to  the  new 
ground  telegraph  system  as  is  now  used  on 
practically  all  the  fronts  thruout  Europe. 
This  is  nothing  more  or  less  than  the 
ground  conductive  system,  and  it  is  not  by 


-  £>e/zz&, 


This  Diagram  Gives  a  Clear  Idea  of  "Ground  Telegraphy."  Current 
Impulses  Sent  Out  Thru  Electrodes  A  and  B  Will  Be  Heard  In  Tele- 
phone Connected  to  Spikes  C  and  D,  Due  to  Current  Leakage. 

any  means  something  new,  having  been 
described  almost  half  a  century  back.  The 
French,  however,  have  added  considerable 
new  features  to  the  system,  as  will  be 
evidenced  in  this  article. 


tery  and  a  buzzer.    If  we  now  drive  two 
further  spikes  C  and  D,  say  fifty  or  one 
hundred  yards  (or  more)  away  from  the 
first  spikes,  paralleling  the  latter,  and  if 
we  connect  spikes  C  and  D  by  means  of  a 
telephone  receiver  T,  then  when  we  operate 
the  buzzer  by  means  of  a  telegraph  key  the 
sounds  will  be  clearly  received  in  the  far 
off  telephone  T. 
The  explanation  is  that  a  certain  amount 
of   current  is  received  by  the 
spikes  C  and  D,  and  the  sound 
while  weak  is  readily  heard  in 
the     telephone     receiver.  Of 
course,  this  is  the  crudest  sys- 
tem, but  it  works  surprisingly 
well  over  equally  surprising  dis- 
tances.   Not  only  is  it  possible 
to  telegraph  over  such  a  sys- 
tem, but  by  substituting  a  micro- 
phone for  the  buzzer,  and  pro- 
vided we  have  enough  current, 
articulate  speech  can  be  trans^ 
mitted  over  such  a  ground  sys- 
tem without  the  use  of  interven- 
ing wires.   It  is  of  course  not  as 
efficient  as  the  "ether  wave"  ra- 
diophone system,  but  has  certain 
military  applications. 
A  system  of  this  kind  works  always  at 
its  best  when  the  spikes  A  and  B  are 
separated  as  far  as  it  is  possible.  The 
further  the  spikes  are  separated,  the  further 
{Continued  on  page  646) 


January,  1918 


ELECTRICAL  EXPERIMENTER 


593 


How  Aurora  Borealis  Affects  Telegraph  and  Cable  Lines 

Here  for  the  first  time,  are  told  the  inside  facts  of  just  how  the  "Aurora  Borealis"  affects 
telephone  and  telegraph  lines,  as  well  as  ocean  cables.  The  facts  presented  are  from  the 
records  of  a  leading  American  electrical  engineer  who  has  been  in  a  position,  fortunately,  to 
carry  on  official  observations  and  tests  on  this  little  understood  phenomenon  for  many  years. 


THE  Aurora  Borealis,  commonly 
called  the  "Northern  Lights,"  pays 
us  a  visit  now  and  then,  the  last 
severe  attack  on  telegraph  and  tele- 
phone circuits,  as  well  as  ocean 
cables,  having  occurred  on  August  9th. 
The  display  was  both  spectacular  and  de- 
moralizing to  man-made  electric  com- 
munication lines.  A  few  words  on  this 
remarkable  phenomenon  and  its  origin, 
which  is  now  thought  to  be  due  to  sun-spots, 
should  be  of  interest. 
"Since  a  magnetic  storm  of  the  intensity 


"The  force  of  that  disturbance,  as  it 
reached  the  earth,  perhaps  in  the  form  of 
torrents  of  electrons,  was  only  sufficient  to 
be  noticed  in  its  effect,  thru  the  magnetic 
currents  of  the  earth,  upon  delicately  bal- 
anced energies  in  electro-magnetic  instru- 
ments ;  but  imagine  it  magnified  ten  times 
or  a  hundred  times,  and  then  what?  Sun- 
spots  and  their  repercussion  upon  the  earth 
have  only  been  studied  for  a  few  decades, 
and  it  is  but  a  few  years  since  we  first  came 
into  possession  of  instruments  and  engines 
depending  on  electricity  for  their  action,  so 


feverish  condition  of  the  sun.  It  seems  as 
if  the  face  of  the  sun  had  broken  out  in  a 
fearful  rash,  so  numerous  and  so  large  are 
the  spots  that  have  been  observed,  some 
even  large  enough  to  be  seen  with  the  naked 
eye. 

"The  sun,"  writes  Flammarion,  "is  always 
a  furnace  of  inconceivable  physical  and 
chemical  phenomena,  bombardments  of  elec- 
trified particles  and  enormous  eruptions  of 
gas,  of  which  we  can  gain  no  idea  even 
from  the  thunder-bolts  of  heaven  which 
flash  in  lightning  from  the  clouds,  nor  from 


T    T     T  T 


TELEPHONE  LINES 


t 


t 


r  t  r 

TELEGRAPH  LINES 


The  "Aurora  Borealis"  Visits  Us  Every  Now  and  Then,  the  Last  One  Having  Occurred  on  August  9,  1917.  At  These  Times  There  are 
Severe  Electrical  Disturbances  Set  Up  on  Telephone  and  Telegraph  as  Well  as  Cable  Lines.    Transient  Electric  Currents  Often  Surge 

Thru  the  Circuits,  Which  Register  a  Potential  of  Several  Hundred  Volts. 


of  that  of  August  9th  demonstrably  has 
power  to  arrest  the  operation  over  a  whole 
continent  and  a  whole  ocean  of  telegraph, 
cable  and  telephone  lines,  how  much  more 
intense  would  a  similar  storm  have  to  be  in 
order  to  stop  the  engines  of  prowling  sub- 
marines and  of  soaring  aeroplanes,  which 
in  one  case  directly  and  in  the  other  in- 
directly depend  for  their  functioning  on 
electricity?  The  source  of  the  disturbance 
is  in  the  sun,  which  exercises  its  power  of 
interference  from  a  distance  of  93,000,000 
miles"  says  a  well-known  scientist. 

"In  these  questions  lies  the  new  signifi- 
cance of  such  a  magnetic  storm  as  that  of 
August  9th,  which  occurred  coincidentally 
with  the  existence  on  the  sun  of  a  vast 
disturbance  that  broke  up  millions  of 
square  miles  of  its  fiery  surface. 


that  we  have  not  yet  experimental  knowl- 
edge of  what  the  maximum  of  this  solar 
explosive  influence  upon  them  may  be. 

"There  are  various  theories  concerning 
the  precise  manner  in  which  the  solar  in- 
fluence is  transformed  to  the  earth.  One  of 
the  most  probable  supposes  it  to  be  done 
thru  shafts  of  invisible  radiations,  resem- 
bling the  cathode  rays,  which  come  from 
the  sun,  and,  upon  meeting  the  atmosphere, 
alter  the  conductivity  of  the  upper  strata 
and  thus  stimulate  the  circulation  of  aerial 
electric  currents.  The  shafts  of  radiation, 
or  of  electrons,  arise  from  centres  of  violent 
disturbance  on  the  sun's  surface." 

A  good  explanation  is  given  by  the  fam- 
ous French  astronomer— Camille  Flam- 
marion, who  explains  in  L 'Illustration  that 
these  northern  lights  are  caused  by  the 


the  thunders  of  man  which  escape  from  the 
monstrous  throats  of  cannon.  These  spots 
on  the  sun  are  actually  at  least  158,000  miles 
in  diameter.  Our  earth  is  about  8,000  miles 
in  diameter,  so  it  could  fall  into  one  of  them 
and  be  lost." 

The  great  streamers  of  light  that  flickered 
over  the  northern  sky,  like  the  rays  of  giant 
searchlights,  on  many  evenings  in  August 
and  September  were,  according  to  Flam- 
marion, radiations  of  electric  light  directly 
from  the  vast  volcanoes  and  fiery  tornadoes 
that  are  torturing  the  face  of  the  sun.  And 
these  radiations  extend  out  as  far  as  the 
orbit  of  Neptune,  more  than  2,793,000,000 
miles  away! 

The  action  of  the  "Northern  Lights"  on 
telegraph  and  other  long  circuits  would 
{Continued  on  page  645) 


594 


ELECTRICAL  EXPERIMENTER 


January,  1918 


The  "Electro-Magnetic  Depth  Bomb"— Terror  of  the  "Subs" 


© 


THE  "Depth  Bomb"  has  been  featured 
in  all  recent  official  and  unofficial 
despatches  in  which  submarine  ac- 
tivities have  figured — much  to  the 
mystification  of  the  man-in-the-street, 
let  it  be  said.  In  the  present  article  the 
general  operating  features  of  the  "depth 
bomb"  are  explained  as  well  as  several  new 
ideas  which  are  being  tried  out,  these  modi- 
fications being  due  to  Mr.  F.  R.  Lewis  of 
New  York,  inventor  of  several  new  war 
appliances,  including  an  improved  aeroplane 
range  finder  for  bomb  dropping,  which  was 
illustrated  and  described  at  length  in  the 
December  number  of  the  Electrical  Ex- 
perimenter. 

Our  front  cover 
illustration  shows 
in  a  striking  man- 
ner one  method  of 
using  the  Lewis 
"depth  bomb."  The 
general  arrange- 
ment of  this  prom- 
ising anti-subma- 
rine device  is 
illustrated  in  the 
accompanying  sec- 
tional drawing. 

This  bomb  while 
harmless  to  vessels 
passing  thru  the 
submarine  zone  is 
sure  death  to  the 
submarine  that 
comes  within  the 
magnetic  radius  of 
its  powerful  elec- 
tro-magnets. The 
bomb  can  be  plant- 
ed in  waters  infest- 
ed by  enemy  sub- 
marines with  the 
aid  of  patrol  boats 
or  hydro-aero- 
planes. By  turning 
the    screw  that 

opens  valve  (9)  to  the  ballast  chamber  (11) 
the  bomb  immediately  sinks  under  the  sur- 
face of  the  water  fifteen  feet,  where  it  lies 
in  wait  for  its  prey.  If  by  chance  a  merchant 
or  patrol  vessel  should  attract  the  bomb,  the 
bomb  would  attach  itself  to  the  side  of  the 
vessel.  It  should  be  understood  that  this 
electro-magnetic  depth  bomb  is  not  of  the 
class  constantly  invented  by  well-meaning 
but  electrically  uninformed  patriots,  wherein 
the  magnet  is  supposed  to  pull  the  ship  or 
the  bomb  thru  a  radius  of  several  yards.  The 
Lewis  depth  bomb  is  fitted  with  powerful 
multipolar  electro-magnets  all  over  its  outer 
shell  in  the  manner  here  shown.  These  are 
not  normally  excited,  but  as  soon  as  a  sub- 
marine comes  within  a  few  feet  of  it,  the 
presence  of  her  iron  mass  causes  a  sensitive 
magnetic  needle  relay  to  close  the  battery 
circuit  thru  the  powerful  electro-magnet 
nearest  to  the  submarine's  hull.  If  the  sub- 
marine is  close  to  the  depth  bomb,  the  bomb 
will  attach  itself  to  the  submarine,  all  un- 
known to  the  "sub's"  crew.  Besides  all  this 
use  is  made  of  a  comprest  air  tank  and  two 
discharge  jets,  one  at  either  end,  the  air  jet 
farthest  from  the  "sub."  being  actuated  by 
a  magnetic  valve  opened  by  the  magnetic  re- 
lay 2.  The  depth  bomb  will  be  propelled 
toward  the  "sub."  by  the  escaping  air,  even 
tho  the  bomb  is  several  yards  away. 

If  a  patrol  or  merchant  vessel  happens  to 
pick  up  any  of  the  electro-magnetic  depth 
bombs,  it  must  be  remembered  that  they 
stay  at  a  fixt  draft,  which  renders  the  bomb 
harmless  to  them,  but  when  a  submarine 
picks  one  up  (all  unknown  to  its  crew)  it 
is  harmless  only  until  the  submarine  dives 
to  fire  a  torpedo  at  its  prey.    The  subma- 


rine must  go  to  a  depth  of  at  least  30  to  35 
feet,  when  the  water  pressure  causes  the 
hydrostatic  valve  (6)  to  work  the  electric 
switch  (5)  which  in  turn  operates  the  spark 
coil  (4)  exploding  a  powerful  high  explo- 
sive charge  in  the  chamber  (15).  The 
charge  is  heavy  enough  to  blow  in  a  plate 
or  two  or  cause  the  plates  to  be  blown  in 
to  such  an  extent  that  the  submarine  would 
sink  in  a  very  few  minutes,  so  that  the  sub- 
sea  craft,  by  its  very  act  to  destroy,  de- 
stroys itself. 

There  is  provided  an  airtight  chamber 
around  all  electrical  parts  and  the  explosive 
chamber,  as  the  bomb  lying  in  the  water, 


1-J/r  escape  2  -  Mog  need/e  re/ay.  3  7~/me  sw  re/eose  4- •  SparA  Co// 
5-Defonoforstv  dosed  i>y  //yd.  i/o/re.  6-  /iyd  ro/ve.  7-  f/ec/r/'c  de/ono/or 
6  <  Magnet  3-  /n to/re  vo/ve.  /O  -Air  yo/ye.  //-  Bo//as/ /o/?A  J2-  Compressed 
o/r  fon/r  /3°  Mag  ya/ve.  /4-T/me  5>y.  /5 '--  Gun- cotton  esptos/ve 


The  "Electro-Magnetic  Depth  Bomb"  Represents  the  Latest  Departure  in  the  Design  of  Anti- 
submarine Devices.    These  Bombs  Are  Harmless  if  Picked  Up  by  Steamships.    When  Picked 
Up  by  an  Enemy  Submarine,  However,  They  Make  Short  Work  of  It,  For  When  the  "Sub" 
Dives,  the  Increased  Water  Pressure  Explodes  the  Bomb. 

would  be  affected  by  the  different  tempera- 
tures which  would  cause  sweating  (conden- 
sation) and  this  moisture  would  sooner  or 
later  cause  the  bomb  to  become  dead  and 
consequently  harmless.  A  special  time 
switch  is  provided  which  keeps  all  circuits 


open  until  after  a  predetermined  time  pe- 
riod, thus  enabling  the  ship's  crew  to  cast 
them  overboard  and  get  away  from  the  spot 
before  the  depth  bomb  becomes  active. 

These  depth  bombs  can  be  cheaply  made 
and  could  be  planted  by  the  hundreds  in 
the  zones  picked  out  for  this  purpose,  at 
night,  (or  by  seaplanes  in  the  daytime)  and 
as  the  bomb  sinks  to  a  depth  of  fifteen  feet, 
there  is  nothing  to  show  the  enemy  where 
danger  lurks.  The  hydro-static  valve  is 
controlled  by  a  tension  spring  and  set-screw 
indicator  which  can  be  adjusted  for  the 
bomb  to  explode  at  a  predetermined  depth 
of  30  to  100  feet. 

The  depth  bomb 
would  seem  to  have 
distinct  advantages 
for  carrying  on 
anti-submarine  op- 
erations in  such 
waters  as  those  off 
the  coast  of  Bel- 
gium, and  in  the 
German  coastal 
waters  of  the 
North  Sea.  The 
Allied  war-vessels 
cannot  enter  these 
thickly  mined  wa- 
ters, anyway.  They 
are  netted  off  to  a 
large  extent  so  that 
floating  depth 
bombs  would  hard- 
ly menace  the  Al- 
lied ships.  But  the 
"Huns"  in  their 
subsea  war-vessels 
know  safe  chan- 
nels thru  the  mined 
areas  and  manage 
to  cut  thru  nets 
and  finally  show  up 
"somewhere  in  the 
Atlantic."  When 
Uncle  Sam's  aerial 
fleet  reaches  the  other  side,  and  even  with 
the  present  Allied  air-fleet,  it  ought  to  be 
possible  to  sow  the  forbidden  water  areas 
with  tens  of  thousands  of  such  electro- 
magnetic depth  bombs.  Depth  bombs  seem 
to  be  very  efficient. 


SUCCESSFUL  RADIO  SCHOOL  UN- 
DER NOVEL  CONDITIONS. 

A  free  Government  school  to  train  radio 
operators  for  the  rapidly-growing  American 
merchant  marine  has  been  established  at 
Boston  thru  the  initiative  of  Radio  In- 
spector Arthur  Batcheller,  of  that  city,  with 
the  active  assistance  of  Mr.  Walter  Butter- 
worth,  assistant  radio  inspector.  When 
Congress  made  its  first  appropriation  for 
building  merchant  vessels  Mr.  Batcheller,  at 
that  time  assistant  radio  inspector  at  Boston, 
was  quick  to  realize  that  a  large  number 
of  commercial  operators  would  be  needed, 
and  in  June  he  suggested  to  the  Commis- 
sioner of  Navigation  the  establishment  of  a 
free  school  which,  unlike  the  great  school 
conducted  by  the  Navy  Department,  would 
accept  only  such  applicants  as  would  agree 
to  take  a  position  in  the  merchant  marine. 
The  suggestion  was  approved  and  Mr. 
Batcheller  was  authorized  to  carry  out  his 
plans. 

Thru  the  cooperation  of  the  collector 
of  customs  permission  was  obtained  to  use 
the  office  of  the  radio  inspector  in  the  Bos- 
ton customshouse  during  the  evening  for 
school  purposes.  Benches  and  tables  were 
made  from  second-hand  lumber  obtained 
thru  the  assistance  of  the  Customs  Ser- 
vice, and  camp  stools  were  loaned  by  the 


Boston  &  Gloucester  Steamship  Co.  Thru 
the  mayor  of  Boston  the  loan  of  a  black- 
board was  secured  from  the  school  depart- 
ment. The  Marconi  Wireless  Telegraph 
Co.  aided  the  project  by  supplying  a  typical 
radio  installation,  and  the  Bureau'of  Navi- 
gation furnished  the  necessary  head  tele- 
phones, telegraph  keys,  dry  cells,  wire,  buz- 
zers, etc. 

These  facilities  permitted  the  instruction 
of  a  class  of  40  men,  and  nearly  that  num- 
ber are  taking  advantage  of  the  opportunity. 
The  classes  meet  three  evenings  a  week  and 
the  work  is  progressing  with  marked  suc- 
cess. The  school  opened  on  July  16,  and 
each  student  will  have  an  opportunity  at  the 
end  of  a  six  months'  course  to  win  a  first- 
grade  commercial  radio  operator's  license. 

The  instruction  is  under  the  supervision 
of  Mr.  Batcheller,  who  had  previously  had 
four  years'  experience  as  a  teacher  of  elec- 
tricity and  radiotelegraphy.  The  Secretary 
of  Commerce  has  visited  the  school  and  has 
officially  commended  Mr.  Batcheller  and 
Mr.  Butterworth  for  their  helpful  and  pa- 
triotic service.  They  have  had  the  active 
assistance  of  Mr.  McCarthy,  clerk  in  the 
radio  inspector's  office,  and  of  Mr.  E.  W. 
Thompson,  chief  electrician,  radio,  United 
States  Navy. 


January,  1918 


ELECTRICAL  EXPERIMENTER 


595 


Electric  Buoys  to  Mark  Torpedoed  Ships 

By  E.  T.  JONES,  Chief  Electrician;  Radio,  U.  S.  N.  R.  F. 


RECENTLY  I  have  seen  and  read  much 
in  regards  to  torpedoed  ships,  the  rais- 
ing and  saving  of  the  same,  and  some 
of  them  are  indeed  excellent  ideas.  Now 
of  late  I  have  been  studying  this  subject 
myself  and  I  have  devised  a  method,  here 
illustrated,  by  which  ships  could  be  raised 
if  the  proper  apparatus  were  used  to  do  so. 

The  main  idea  is  to  fit  all  merchant  ships 
with  the  buoys  shown,  having  enclosed  in- 
side of  them  coils  of  cable  on  a  reel  which 
unwind  as  the  ship  goes  down.  The  buoy 
staying  afloat  access  can  be  had  to  the  cable 
by  means  of  an  entrance  at  the  top  of  the 
buoy.  The  ship  could  be  fitted  with  eight 
or  more  of  these  "floaters"  and  by  using 
powerful  floating  cranes 
or  other  means  of  lift- 
ing, the  lost  ship  could 
easily  be  brought  to  the 
surface  and  then  towed 
to  shallow  water  where 
it  could  be  entirely 
saved. 

It  is,  of  course,  taken 
into  consideration  if  the 
ship  were  sunk  in  mid- 
ocean  that  the  cable 
could  not  be  long 
enough,  in  fact  the  buoy 
would  have  to  be  too 
large,  but  if  each  ship 
were  fitted  with  these 
buoys  and  a  reasonable 
amount  of  cable  in- 
serted in  each  it  would 
be  no  more  than  taking 
another  chance,  but  this 
time  a  chance  which 
would  probably  save  the 
ship. 

The  buoys  themselves 
could  even  be  supplied 
with  food  when  near- 
ing  the  danger  zone  and 
should  the  ship  be  sunk 
this  food  could  be  used 
by  the  victims  until  re- 
lief came.  Means  of 
holding  on  to  the  buoy 
could  also  be  supplied 
and  add  to  the  life  sav- 
ing devices  now  sup- 
plied on  board  every 
ship. 

Several  details  of  im- 
portance would  have  to 
be  taken  into  considera- 
tion with  such  a  device 
as  this.  For  one  thing 
the  enemy  would  surely 
cut  the  cables  if  the 
buoys  floated  to  the  sur- 
face as  soon  as  the  ship  sank.  Some  kind 
of  retarding  device,  such  as  a  slow-empty- 
ing ballast  tank,  would  solve  this  problem, 
so  that  the  buoys  would  float  to  the  surface 
only  after  a  period  of  several  hours. 

Further,  it  is  not  feasible,  as  aforemen- 
tioned, to  fit  these  buoys  with  a  great  length 
of  heavy  cable.  Therefore,  it  would  seem 
a  good  idea  to  equip  the  buoys  with  reels 
of  fine  steel  wire  only,  which  could  then  be 
of  considerable  length,  owing  to  its  light 
weight.  Under  each  buoy  position  on  the 
vessel  there  could  be  provided  a  magazine 
chamber  in  the  hold,  in  which  a  suitable 
length  of  heavy  steel  cable  could  be  stored 
on  a  reel.  The  action  of  the  buoys  so 
equipt  would  then  be  as  follows : 

Say  the  vessel  was  torpedoed ;  the  eight 
or  more  buoys  would,  after  several  hours, 
float  to  the  surface,  carrying  their  fine  wire 
connections  from  the  sunken  craft.  If  now 
salvage  operations  are  to  be  started  in  an 
effort  to  raise  the  wreck,  the  buoy  covers 


are  opened  and  by  pulling  up  on  the  small 
wires,  automatic  clutches  are  released  on 
the  deck  of  the  sunken  boat,  permitting  the 
heavy  cable  in  the  magazines  to  be  pulled 
up.  After  the  heavy  cables  are  all  pulled 
up  to  the  surface,  they  are  made  fast  to  the 
lifting  derricks.  For  that  matter  it  would 
also  be  practical  to  arrange  a  second  buoy 
to  float  the  heavy  cable  to  the  surface,  this 
buoy  being  released  by  pulling  on  the  fine 
guide  wires  already  described.  The  buoys 
would  be  fitted  with  a  storage  or  other  bat- 
tery to  light  the  lamp  and  an  automatic 
switch  to  close  the  lamp  circuit  after  the 
buoy  reached  the  surface. 


a  time  when  electrical  merchandise  played 
the  part  it  will  this  year. 

These  facts,  and  others,  have  all  received 
the  most  careful  attention  in  a  book  just 
publisht  by  the  Society,  which  is  being  sent 
gratis  to  members  and  non-members  alike, 
upon  request.  It  is  designed  for  Central 
Stations  and  dealers  who  have  Arrived, 
those  who  are  Already  There,  those  who 
are  Going,  and  the  Just  Started.  It  is  a  big 
book,  48  pages  and  covers,  printed  in  many 
colors,  profusely  illustrated  thruout,  and 
filled  with  practical,  timely  suggestions, 
built  for  stores  of  all  sizes  in  cities  of  all 
sizes. 

The    book   has    some   twenty  chapters, 


One  of  Uncle  Sam's  Naval  Men  Has  Suggested  a  New  Salvaging 
poses  to  Equip  Every  Boat  with  a  Series  of  Electrical  Buoys,  whi 
Carry  Cables  From  the  Ship,  and  May  Carry  Electric  Lig 


AMERICA'S  ELECTRICAL  CHRIST- 
MAS CAMPAIGN 

Some  years  ago,  Thomas  Edison  predict- 
ed that  it  wouldn't  be  very  long  before 
practically  everything  that  required  labor  in 
the  home,  would  be  done  by  "electricity." 

Everyone  knows  to  what  extent  labor, 
time  and  money  saving  electrical  appliances 
have  been  introduced  into  the  home,  and 
how  energetically  and  successfully  central 
stations,  electric  shops,  contractors  and 
others  have  been  promoting  the  use  of  such 
devices.  But  it  has  been  only  with  the  sud- 
den descent  of  war  upon  this  country  that 
the  full  meaning  of  Edison's  words,  and 
their  great  portent  comes  to  us. 

Apropos  of  this  question  of  selling  Elec- 
trical appliances,  this  year's  campaign  of 
The  Society  for  Electrical  Development ; 
"America's  Electrical  Christmas"  comes 
along  at  a  most  opportune  time.  Never  be- 
fore in  the  history  of  the  industry  was  there 


Scheme  for  Saving  Sunken  Ships.  He  Pro- 
ch  Rise  when  the  Ship  Sinks.  These  Buoy» 
hts  as  Well  as  Food  for  the  Survivors. 


treating  on  everything  from  the  store  and 
window  display,  to  the  use  of  two  very  ex- 
cellent "movie  films"  which  the  Society  has 
prepared,  in  cooperation  with  the  Universal 
Film  Mfg.  Co.  All  the  helps,  copy,  cuts, 
etc.,  are  furnished  practically  free  to  mem- 
bers and  non-members  along  the  same  broad 
liberal  policy  heretofore  manifest  in  such 
previous  campaigns  as  America's  Electrical 
Week,  Electrical  Prosperity  Week,  Wire- 
Your-Home-Time,  etc.  Readers  are  advised 
to  correspond  with  the  Society  for  Elec- 
trical Development,  29  West  39th  Street, 
New  York  City. 


SALVADOR— MEXICAN  WIRELESS. 

Wireless  communication  has  been  estab- 
lisht  between  Mexico  City  and  San  Sal- 
vador. The  wireless  plant  at  the  Salvado- 
rean capital  was  presented  to  that  country 
by  Mexico  and  installed  by  Mexican  elec- 
tricians. 


596  ELECTRICAL  EXPERIMENTER  January,  1918 

Training  U.  S.  Aviators  with  Electric  Map 


UNCLE  SAM  has  a  real  job  on  his 
hands  now — namely,  to  train  thou- 
sands of  aviators  in  a  few  months. 
And  they  must  be  good  aviators — 
capable  of  looping  the  loop  with 
one  hand,  if  need  be — while  with  the  other 
they  proceed  to  flash  a  radio  report  to  earth, 
telling  just  where  the  shells  are  hitting. 
Therefore,  every  student  learns  wireless ; 
no  one  can  gain  his  commission  without 
passing  a  rigid  examination  in  this  in- 
dispensable art.  Probably  the  most  interest- 
ing work  is  that  performed  in  the  minia- 
ture range.     This  gives  the  student  that 


preliminary  instruction  in  artillery  spotting 
which  is  perhaps  the  most  useful  service 
rendered  by  the  aeroplane,  says  Burton  J. 
Hendrick  in  the  World's  Work.  In  one  of 
the  instruction  halls  at  Ohio  State  University 
is  an  immense  picture  map  of  a  section  of 
Belgium.  It  shows  the  city  of  Ypres  and 
all  the  surrounding  country,  including  every 
farmhouse,  barn,  country  road,  open  field, 
river  and  pond.  In  a  gallery,  about  ten  feet 
above  this  map,  sit  several  of  our  future 
aviators.  They  are  supposed  to  be  in  aero- 
planes, six  thousand  feet  in  the  air. 

The  scale  of  the  map  is  so  graduated  that, 
as  they  gaze  down  upon  it,  the  terrain  ap- 
pears precisely  as  it  would  look  were  these 
men  actually  flying  in  the  air  at  that  height. 
Their  business  is  to  locate  "exploding 
shells"  and  wireless  back  to  their  own  bat- 
teries the  accuracies  or  inaccuracies  of  the 
aim.    And  shells  are  actually  exploding  all 


the  time  on  this  miniature  sketch  of  Belgian 
territory  below  them ;  not  real  shells,  per- 
haps, but  representations  that  convey  a 
complete  illusion. 

Under  the  map,  which  is  of  paper  and 
therefore  transparent  to  light,  are  located 
hundreds  of  little  electric  light  bulbs.  The 
professor,  by  touching  the  appropriate  but- 
ton on  a  lamp  control  switch-board,  can 
light  his  selected  bulb,  the  little  flash  ap- 
pearing on  the  map  giving  a  complete  rep- 
resentation of  an  exploding  shell.  The  ap- 
prentice airman  in  the  gallery  selects  the 
German  battery  which  his  own  men  are  at- 


tempting to  destroy.  The  professor  touches 
off  his  imitation  shells  in  close  proximity 
to  this  battery — these  are  supposed  to  rep- 
resent American  attempts  to  reach  the 
mark.  As  soon  as  each  shell  explodes,  a 
tapping  is  heard  up  in  the  little  gallery;  the 
student  is  wirelessing  to  his  friends,  telling 
them  how  far  they  have  come  from  hitting 
the  object. 

The  wireless  message  may  take  such 
cryptic  form  as  telling  the  American  bat- 
tery that  it  is  "ten  o'clock  and  three  hun- 
dred yards."  This  may  puzzle  most  people, 
but  it  locates  precisely  the  spot  where  the 
shell  has  fallen.  For  purposes  of  signaling 
the  German  battery  is  taken  as  the  centre 
of  a  clock,  with  twelve  o'clock  pointed 
perhaps  due  north.  When  the  airman 
signals  "ten  o'clock"  this  means  that  the 
shell  has  exploded  on  an  imaginary  line 
which  would  represent  the  clock  pointer  in 


this  direction.  The  "three  hundred  yards" 
gives  the  distance  between  the  exploding 
shell  and  the  German  battery. 

The  business  of  the  student  is  to  locate 
these  exploding  shells  almost  instantane- 
ously. Unless  he  gains  great  proficiency 
in  a  short  time,  he  has  no  future  in  the 
American  air  service.  In  no  department  of 
the  service  can  mistakes  become  so  costly 
and  cause  the  loss  of  so  many  lives.  The 
fate  of  battles  may  easily  depend  upon  the 
reliability  of  the  information  wirelessed 
back  by  these  aerial  scouts.  Clearly  this  is 
no  business  for  a  boy  who  does  not  have 
sharp  eyes,  a  perceiving  brain,  a  quick  wit 
and  absolutely  boundless  courage.  The 
young  men  at  the  Ohio  State  University, 
perched  in  their  gallery  above  this  map 
of  Belgium,  can  exercise  all  their  gifts  of 
observation  and  all  the  quick  mental  re- 
actions necessary  to  fulfill  their  duty,  but 
they  cannot,  after  all,  reproduce  all  the  at- 
mosphere of  the  aerial  battlefield.  In  the 
calm  of  this  university  hall  he  works  in 
peace,  while,  when  in  action,  he  will  be 
threatened  with  attack 'by  German  airmen, 
constantly  seeking  to  interrupt  his  little 
game.  The  school  experience  can  train  the 
future  airmen's  skill,  but  it  cannot  train  his 
nerves.  The  rapidity  with  which  the 
students  are  learning  this  art,  however,  and 
the  eagerness  which  they  manifest  in  the 
entrancing  game,  argues  well  for  their 
actual  work  in  the  field. 

Eight  weeks  they  spend  in  the  ground 
school.  Those  who  survive  this  experience 
are  past  on  to  the  flying  field,  such  as  that 
at  Dayton.  Here  they  continue  their  school 
work  and  also  learn  the  real  work  of  flying 
a  plane  and  after  eight  weeks  here  they  are 
transported  silently  to  an  American  port 
and  shipt  to  France.  Here  an  American 
aviation  school  receives  them,  and  thence 
they  advance,  by  slow  stages,  to  the  "front." 


SCIENCE  AND  INDUSTRY. 

Sir  Isaac  Newton,  shortly  before  his 
death,  said :  "I  do  not  know  what  I  may 
appear  to  the  world,  but  to  myself  I  seem 
to  have  been  only  like  a  boy  playing  on  the 
seashore,  and  diverting  myself  in  now  and 
then  finding  a  smoother  pebble  or  a  prettier 
shell  than  ordinary,  whilst  the  great  ocean 
of  truth  lay  all  undiscovered  before  me" — 
yet  Liebnitz  estimated  that  Newton  had 
achieved  far  more  than  all  other  mathema- 
ticians put  together  from  the  beginning  of 
history.  Lord  Kelvin,  at  his  jubilee,  in  reply 
to  the  homage  of  the  whole  scientific  world, 
said :  "One  word  characterizes  the  most 
strenuous  of  the  efforts  for  the  advancement 
of  science  that  I  have  made  perseveringly 
during  fifty-five  years ;  that  word  is  failure. ' 
Yet  he  towered  above  all  his  scientific  con- 
temporaries, and  was  perhaps  the  greatest 
savant  that  the  world  has  known.  It  is,  in 
fact,  a  trait  common  to  all  who  have  spent 
their  lives  in  the  pursuit  of  knowledge,  and 
have  acquired  a  profound  acquaintance  with 
the  hidden  mysteries  of  nature  and  science, 
that  they,  more  than  all  others,  realize  the 
immensity  of  the  field  that  lies  open  before 
them — shrouded  in  mists,  it  is  true,  and 
beset  with  pitfalls,  culs  de  sac,  false  clues, 
but  also  holding  treasure  in  store  of  in- 
conceivable richness  for  the  reward  of  those 
who  patiently  grope  amid  its  gloomy  fast- 
nesses. We  have  as  yet  but  ventured  over 
the  border  of  that  illimitable  expanse;  the* 
further  we  penetrate  into  its  depths  the  bet- 
ter we  appreciate  the  wealth  that  lies  be- 
yond, and  the  greater  becomes  our  strength 
to  overcome  the  difficulties  that  confront  us. 
We  see,  too,  how  far  we  have  strayed  from 
the  true  path  in  the  complacent  past  when 
we  thought  we  had  approached  finality  in 
one  or  another  quest. 


The  U.  S.  Aviation  School  At  a  Western  University  Has  Adopted  an  Electric  Map  for  Coach- 
ing Future  Birdmen.    The  Instructor  Pushes  a  Button,  a  Light  Under  the  Map  Flashes,  and 
the  Students  In  the  Balcony  Must  Instantly  Locate  Where  the  Supposed  Shell  Hit.  The 
Students  Telegraph  Their  Results  To  the  Instructor. 


January,  1918 


ELECTRICAL  EXPERIMENTER 


597 


"Liberty  Loan"  Electric  Signs 


THE  good  people  of  New  York  City 
were  not  permitted  to  go  pleasure- 
hunting  along  the  "gay  white  way," 
without  being  frequently  reminded 
that  "your  patriotic  duty  is  to — BUY 
A  LIBERTY  BOND!"  Electric  signs  large 
and  small  blazed  the  immortal  message 
forth  so  successfully  that  the  metropolis 
out-bid  itself  and  bought  considerably  more 
than  its  allotted  share  of  patriotism. 

The  accompanying  photographs  show  the 
Wrigley  Electric  Sign  with  Liberty  Loan 


the  pronoun  "She"  when  referring  to  fuses. 
Their  action  was  based  on  the  fact  that  a 
fuse,  like  a  woman,  "goes  off"  when  least 
expected. 

A  prominent  storage  battery  manufac- 
turer has  announced  that  powdered  glass 
is  highly  unsuitable  for  filling  storage  bat- 
teries. 

*    *  * 

A  recent  Underwriter's  ruling  prevents 
the  laying  of  wires  or  cables  in  existing 


While  drawing  short-circuits  on  feeders 
it  is  suggested  that  dark  glasses  be  worn 

to  protect  the  eyes. 

*  *  * 

Special  wet  cells  have  been  devised  for 
use  in  "prohibition"  states. 

*  *  * 

From  close  observation  extending  ovei 
a  number  of  years  an  efficiency  engineer 
has  calculated  that  the  depreciation  on  an 
electrical  doorbell  equipment  is  163.3  per 
rent,  the  first  year,  decreasing  some  23  per 


legend — also  the  Budweiser  Electric 
Sign  and  two  other  attractive  electric 
signs, — the  Wreath  at  48th  Street  and 
7th  Avenue,  showing  into  Longacre 
Square  and  a  sign  at  Broadway  and 
103rd  Street,  both  donated  by  the  O.  J. 
Gude  Company. 

In  Times  Square  an  electric  sign 
which  was  seen  by  1,000,000  people 
every  twenty-four  hours  was  given  to 
the  government  to  advertise  the  second 
Liberty  Loan.  The  sign  was  donated 
by  William  Wrigley,  Jr.,  the  chewing- 
gum  manufacturer,  for  the  use  of  the 
Liberty  Loan  committee  during  Oc- 
tober. 

The  statistics  of  the  gigantic  Wrigley 
\      sign  are  as  follows  : — The  structure  ex- 
tends 56  feet  in  height  and  200  feet  in 
length.   At  either  end  are  two  magnifi- 
cent fountains  34  feet  high,  at  the  top 
of  the  sign  in  the  center  are  two  ma- 
jestic peacocks  facing  each  other,  each 
60  feet  long  from  head  to  tip  of  shimmering 
tail.    The  artistic  gold  scroll  work  border 
of  the  sign  is  entwined  with  beautiful  varied 
colored  flowers — all  reproduced  in  electric 
globes  —  approximately    15,000    of  which 
showing  eight  different  colors,  are  required 
for  the  sign.    The  reproductions  of  the 
famous  Spearmen,  three  on  each  side  of  the 
sign,  are  15  feet  high.    These  jolly  little 
men  are  in  constant  action — they  dance,  sa- 
lute,  march,   shoulder   arms   and  present 
arms.   The  sign  costs  $5,000  a  month  to  run. 
The  Budweiser  sign  is  44  feet  high  by  73 
feet  long,  and  the  Eagle  is  24  feet  high,  by 
22  feet  wide.    The  Wreath  is  33  feet  high, 
and  the  sign  at  103rd  Street,  while  not  as 
large  as  the  lower  Broadway  signs,  has  a 
showing  as  far  as  96th  Street — one  of  the 
most   important   night   sections   of  upper 
Broadway. — Photos  courtesy  O.  J.  Gude 
Company. 


ECCENTRIC  ELECTRIC  EFFLUVIA. 
By  Thomas  W.  Benson. 
Despite  the  number  of  petticoats  on  a 
high  tension  insulator  they  do  not  notice- 
ably hamper  the  kick. 

*    *  * 

The  International  Brotherhood  of  Blow- 
outs at  their  last  annual  convention  adopted 


How  New  York  Boosted  the  "Liberty  Loan" 
With  Flashing  Electric  Signs.  "Buy  a  Lib- 
erty Bond"  Greeted  Your  Eyes  from  Every 
Angle.  Upper  Left  View  Shows  Mastodonic 
Sign  Donated  By  William  Wrigley,  Jr.,  the 
Chewing  Gum  Manufacturer.  It  Measured 
200  Ft.  in  Length. 

water  pipes,  on  account  of  the  damping  ef- 
fect experienced  in  the  past. 

*  *  * 

Water  has  been  found  to  be  a  poor  sub- 
stitute for  oil  in  transformers. 

*  *  * 

At  present  tests  are  being  made  with  a 
new  type  of  ship  that  has  one  half  ot  the 
hull  made  of  copper  and  the  other  half  of 
zinc.  Calculations  tend  to  show  that  the 
electrical  energy  derived  from  the  battery 
thus  formed  will  give  the  craft  a  speed  of 
some  17.3  yards  per  minute. 

*  *  * 

Brocaded  arc  lamps  with  sateen  ruffles 
have  been  announced  by  a  Chicago  concern. 
It  is  reasonable  to  presume  that  they  will 
meet  with  great  demand  by  the  fashionable 

ladies  for  their  boudoirs. 

*  *  * 

Cast  glass  boots  are  being  supplied  to  the 
linemen  of  a  power  company  in  the  middle 
west  to  protect  them  from  shocks. 

*  *  * 

The  DeNutt  Power  Co.  have  equipt  all 
their  engine  room  chairs  with  glass  legs  so 
the  operatives  in  the  generating  plant  may 
lean  against  the  bus-bars  without  danger. 
That's  comfort! 

*  *  * 


cent,  each  succeeding  year  for  five  years, 
the  entire  life  of  the  usual  outfit. 

#    -jp  * 

Acting  on  the  well-known  fact  that 
a  copper  wire  offers  a  certain  amount 
of  resistance,  professors  at  St.  Vitas 
College  have  attempted  to  remedy  this 
by  removing  the  copper  from  electrical 
conductors.  No  accurate  data  is  avail- 
able regarding  the  results,  but  we  be- 
lieve they  have  not  been  successful. 

Babbit  metal  is  not  advised  as  an  in- 
sulating filling  for  high  tension  trans- 
formers or  spark  coils. 

An  attempt  to  use  one  wire  for 
feeder  and  return  has  failed,  according 
to  recent  reports  from  Dubort,  Mich. 

A  novel  method  of  extinguishing  an 
incandescent  lamp  under  some  condi- 
tions is  to  tap  it  with  a  small  hammer.  Two 
or  three  taps  are  usually  sufficient  to  obtain 
the  results  desired. 

The  carrying  capacity  of  a  plug  fuse  may 
be  appreciably  increased  by  filling  it  with 
mercury. 

*    *  # 

Water  turbine  generating  sets  have  been 
falling  into  disuse  as  watchfobs  of  late ; 
steam  plants  seem  to  be  taking  their  place 
in  many  localities. 

By  clamping  the  shaft  of  an  ordinary 
electric  fan  in  a  vise  and  switching  on  the 
current  a  very  interesting  collection  of  by- 
products is  thus  formed. 


MAZDA  LAMP  PRODUCTION. 

In  1907  the  carbon  electric  incandescent 
lamp  business  represented  99  per  cent  of  the 
total  sales ;  in  1916  the  relative  proportion 
between  these  lamps  and  the  Mazda  lamp 
has  practically  been  reversed.  The  change 
has  been  brought  about  since  the  public  has 
learned  that  the  Mazda  lamp  will  give  three 
times  the  amount  of  light  as  the  carbon 
lamp  will  give  on  the  same  amount  of 
electricity. 


598  ELECTRICAL  EXPERIMENTER  January,  1918 

.1  ,.!■,■ 

Bronze  Tablet  to  Mark  First  Edison  Station  in  New  York 


TWENTY -TWO  pioneers  of  the 
electric  lighting  industry  assembled 
at  the  Electrical  Exposition  in  New 
York  City  on  October  18th  to  take 
part  in  the  dedication  of  a  tablet 
which  is  to  mark  the  site,  at  257  Pearl 


to  have  time  to  attend  the  historic  event. 

Among  the  central-station  pioneers  who 
gathered  at  the  reunion  were  William  J. 
Hammer,  Schuyler  S.  Wheeler,  E.  A.  Har- 
lev,  H.  A.  Campbell,  Joseph  Lee,  A.  T. 
Brown,  O.  J.  P.  Lang,  A.  E.  Gilbert,  W.  J. 


six  in  number,  were  each  of  ISO  horse- 
power. The  territory  served  by  the  station 
was  only  a  square  mile  in  area  and  the 
station  began  operation  Sept.  4,  1882,  at 
3  P.  M.,  with  four  hundred  lights  on  the 
system,  and  on  Oct.  14,  1882,  about  six 


Photo  from  Central  News  Photo  Service 


Handsome  Bronze  Tablet  Which  Now  Marks 
the  Location  of  First  Edison  Central  Station 
at  257  Pearl  St.,  in  New  York  City. 


Photo  courtesy  New  York  Edison  Co. 


Interesting  Picture  of  the  First  Edison  Central  Station  in  America,  Which  Was  Officially 
Started  Sept.  4,  1882,  With  a  Load  of  Four  Hundred  Lights  on  the  System.    In  Six  Weeks' 
Time  the  Load  Had  Increased  to  2,323  Lamps. 


Street,  of  New  York's  first  electric  cen- 
tral station.  Among  the  men  were  many 
who  worked  with  Edison  in  laying  out 
the  original  station  and  distribution  sys- 
tem. Edison  himself,  however,  was  unable 
to  attend  the  dedication — his  work  on  the 
Naval  Consulting  Board  taking  up  all  his 
time. 

Addresses  were  made  by  Boro  President 
Marcus  M.  Marks,  of  Manhattan ;  Dr. 
George  F.  Kunz,  president  of  the  American 
Scenic  and  Historic  Preservation  Society ; 
John  W.  Lieb,  president  of  the  National 
Electric  Light  Association ;  Reginald  Pel- 
ham  Bolton,  Dr.  Ed- 
ward Hagaman  Hall 
and  P.  C.  Magnus, 
occupant  of  the 
building  on  which 
the  tablet  has  since 
been  placed.  Arthur 
Williams,  president 
of  the  Electrical 
Exposition  pre- 
sided. 

A  feature  of  the 
exercises  was  the 
gathering  of  22  of 
the  men  who  worked 
with  Edison  in  es- 
tablishing the  first 
central  station  at 
257  Pearl  Street, 
where  the  tablet  has 
since  been  placed. 
Some  of  these  men 
are  now  executives 
of  big  electrical 
companies.  All 
cheered  enthusiasti- 
cally when  the  an- 
nouncement was 
made  that  their  old 
boss,  A  1  Edison, 
was  too  busy  helping 
to  win  the  big  war 


Brown,  J.  F.  Atkins,  T.  T.  Wooley,  Edward 
G.  Acheson,  Wilson  S.  Howell,  Richard 
Darlington,  Thomas  Brown,  W.  T.  Demp- 
sey,  Airs.  Nellie  Curran,  Andrew  Brown, 
John  W.  Lieb,  Arthur  Williams. 

The  bronze  tablet  has  since  been  erected 
at  257  Pearl  Street,  New  York,  marking 
the  site  of  the  first  Edison  electric  lighting 
central  station  plant  in  America  and  com- 
memorating the  beginning  of  Edison  service 
in  the  metropolis.  The  bas-relief  at  the 
top  of  the  tablet  shows  the  interior  of  the 
old  Pearl  Street  station.  (See  also  sepa- 
rate view  of  old  station.)    The  generators, 


This  Powerful  Turbo 
"Jumbo"  Dynamos  Sh 


Photo  courtesy  of  General  Electric  Co. 
generator  of  Modern  Type,   Not  So  Much   Larger  Than  the  Early 
own  Above,  Develops  67,000  H.P.    The  "Jumbo,"  a  Wonder  In  Its  Day, 
Developed  150  H.P.  Or  1-450  As  Much. 


weeks  later,  there  were  85  houses  connected, 
wired  for  2,323  lamps. 

In  erecting  the  tablet,  the  American 
Scenic  and  Historic  Preservation  Society 
and  the  New  York  Edison  Company  have 
cooperated.  On  September  4,  1882,  electric 
current  was  generated  by  the  six  150-horse- 
power  "Jumbo"  dynamos,  each  dynamo 
weighing  60,336  lbs.,  or  roughly  30  tons, 
and  having  a  capacity  of  1750-16  C.  P.  Edi- 
son lamps  each.  Up  to  the  time  of  the  con- 
struction of  Edison's  giant  "Jumbos,"  two 
men  could  lift  almost  any  other  dynamo  in 
the  world.  Today  these  dynamos  would 
seem  very  small ; 
probably  even  these 
pioneers  with  all 
their  confidence  and 
prescience  never 
conceived  how  the 
force  to  whose  gen- 
eration this  plant 
was  devoted  was 
destined  to  revolu- 
tionize the  life  of 
the  city.  Save  Edi- 
son; for  even  be- 
fore he  perfected 
the  incandescent 
lamps,  which  on  that 
afternoon  blazed  out 
four  hundred  strong 
at  the  turn  of  the 
station  switch,  he 
had  invented  a  mo- 
tor modeled  on  the 
dynamo  which  he 
himself  had  also  de- 
signed. In  1888  some 
printing  presses  on 
Pearl  Street  were 
operated  by  the 
strangely  successful 
application  of  elec- 
tricity and  this 
(Con.  on  page  (A7) 


January,  1918 


ELECTRICAL  EXPERIMENTER 

The  X-Ray  on  the  Battle  Front 


599 


AFTER  many  trials  and  tribulations 
it  is  indeed  fortunate  to  secure  the 
accompanying  photographs  showing 
a  few  of  the  great  marvels  being 
accomplisht  in  war-ravaged  Europe 
by  means  of  Rontgen   rays,  and   we  are 


Fig.  4.  The  Case  of  Private 
"J.  M.,"  B.  E.  F.  The  Bullet 
Fractured  the  Bone  and  De- 
flected to  the  Position  Shown. 


greatly  indebted  to  Captain  Dr.  Thurston 
Holland  of  Manchester,  England,  for  the 
Figs.  1  and  2  here  shown.  For  every  inven- 
tion and  appliance  made  to  make  the  war's 
toll  large,  the  Red  Cross  and  Medical  Units 
are  equally  struggling  to  alleviate  the  suffer- 
ings of  the  wounded  and  bring  back  to  use- 
fulness the  shattered  limbs  of  our  heroes. 
All  the  photos  are  authentic  and  show  real 
conditions  as  they  exists  at  the  present  time. 

We  are  indebted  to  Captain  Dr.  J.  D. 
Morgan,  of  the  British  Army  Medical 
Corps  for  Figs.  3  and  4,  in  archives  of 
Radiology  and  Electrotherapy,  London. 

The  greatest  benefit  probably  comes  from 
the  ability  of  locating  shrapnel,  as  this 
usually  covers  a  wide  area  in  the  affected 
parts  as  shown  in  Fig.  1,  a  photo  showing 
a  shrapnel  shell  wound  in  the  hand. 


Fig. 


2.  "A  Bullet  in  the  Brain"  Was  the  Diagnosis  of  the 
X-ray  in  This  Case — and  the  Victim  Lived. 


A  peculiar  case  is  cited  in  connection  with 
Fig.  2,  the  photo  showing  a  bullet  in  the 
brain.    A  young  officer  was   wounded  in 


battle  and  in  the  rush  and  hurry  at 
the  advanced  dressing  station,  the 
bruise  on  the  head  was  taken  for  a 
slight  scalp  wound.  While  on  leave, 
he  complained  of  a  pain  in  his  head 
and  decided  to  have  the  surgeons 
make  a  thoro  examination,  when  to 
both  their  own  and  the  officer's  sur- 
prise, upon  using  the  X-rays,  it  was 
found  that  he  had  been  walking 
around  with  a  bullet  in  his  brain. 

In  Fig.  3,  may  be  seen  some  of  the 
terrible  havoc  that  shrapnel  is  doing. 
In  this  radiograph  the  shattered  bones 
may  be  seen  and  also  the  safety-pins 
which  are  holding  the  bandage  around 
the  hand  and  arm.  Fig.  4  shows 
wherein  the  new  methods  of  exact 
location  of  foreign  bodies  may  be 
practically  applied.  The  difficulty  of 
estimating  the  depth  of  the  bullet 
is  obvious  and  the  bullet  is  distinctly 
shown,  also  a  fracture  of  the  bone 
resulting  most  likely  from  the  bullet 
striking  same  with  resulting  deflec- 
tion. 

Thru  the  courtesy  of  Dr.  Sinclair 
Tousey  of  New  York  we  give  the 
folowing  data  on  the  new  methods 
now  being  used  in  accurately  localiz- 
ing foreign  bodies  by  X-rays,  there- 
by eliminating  all  guesswork  on  the 
part  of  the  surgeon  when  he  starts 
to  remove  a  bullet  or  other  foreign 
body. 

Localization  by  means  of  radiography 
presents  no  difficulty  in  the  case  of  a  finger. 
Here  there  are  distinct,  long  land-marks 
and  it  is  easy  to  take  two  pictures  in  planes 
at  a  right-angle  to  each  other.  And  if  we 
employ  a  ray  vertical  to  the  plate  at  the 
supposed  position  of  the  foreign  body,  the 
latter  is  so  near  the  plate  that  no  correction 
is  required  for  the  slight  lateral  displace- 
ment of  its  shadow,  if  not  exactly  at  the 
spot  where  the  ray  is  normal. 

In  many  other  cases  two  radiographs 
taken  at  right-angles  are  either  impractic- 
able or  are  totally  inadequate,  owing  to  the 
thickness  of  the  part  X-rayed,  the  absence 
of  very  accurate  long  land-marks  and  very 
often  the  great  distance  of  the  foreign  body 
from  the  surface.  In  these  cases  radio- 
graphic localization  resembles  a  problem  in 
surveying  like  the  exact  localization  of  a 
point  upon  an  island  by  observations  from 
the  mainland.  The  exact  depth 
at  which  the  foreign  body  is 
located  is  the  difficult  problem 
to  be  solved  and  solved  quickly. 

With  this  end  in  view  some 
fifty-seven  methods  of  radio- 
graphic localization  have  been 
publisht,  many  of  them  called 
forth  by  experience  gained  in 
the  European  war.  The  many 
methods  employed  may  be  said 
to  follow  somewhat  the  follow- 
ing general  plan  : — The  patient 
is  placed  in  an  appropriate  posi- 
tion in  contact  with  the  photo- 
graphic plate,  a  small  metallic 
marker,  fastened  to  the  surface 
of  the  body,  shows  in  the  pic- 
ture and  so  does  the  foreign 
body;  then  without  changing 
the  position  of  the  body  rela- 
tive to  the  plate,  but  with  a 
measured  displacement  of  the 
X-ray  tube  a  second  picture 
is  made.  The  two  positions  of 
the  image  of  the  foreign  body 
afford  a  means  of  determining 
the  direction  and  distance  of 
the  foreign  body  from  the  spot  where  the 
metallic  marker  is  fastened  to  the  surface. 
Or  the  finished  picture  may  be  laid  on  the 


Fig.  1.  "Explosive"  Effect  of  Shrapnel  Shell  in  the 
Hand.  The  Shell  Splinters  Are  Clearly  Visible  in 
This  Skiagram  Taken  At  a  British  Base  Hospital 


table  and  above  it  are  fastened  two  points 
in  the  positions  occupied  by  the  anticathode 
of  the  X-ray  tube  during  the  two  exposures. 
From  these  two  points  threads  are  stretched 
to  the  two  images  of  the  foreign  body  and 
the  juncture  of  intersection  of  these  two 
threads  is  the  point  at  which  the  foreign  body 
was  located  when  the  pictures  were  made. 

Dr.  Tousey's  localization  method  is  new 
and  distinctive,  as  well  as  a  modification, 
of  the  above  method.  The  apparatus  re- 
quired is : — A  piece  of  galvanized  iron  net- 
ting measuring  8x10  inches  and  having 
meshes  %  inch  square  and  the  wire  being 
of  such  a  thickness  itself  that  there  are 
seven  meshes  to  the  linear  inch.  A  single 
distinctive  lead  marker  such  as  a  small  ring 
is  also  used  as  well  as  a  set  of  lead  numer- 
als. There  are  also  facilities  for  movine 
the  X-ray  laterally  a  measured  distance 
(Continued  on  page  636) 


Fig.  3.  The  Case  of  Private 
"W.  D.,"  B.  E.  F.  Showing 
What  Happened  When  the 
Bullet  Struck  the  Bone, 
Shattering  It.  Note  the 
Bandage  Pins. 


600 


ELECTRICAL  EXPERIMENTER 


January,  1918 


HOW    A    GERMAN  TELEPHONE 
OUTPOST  LOOKS 

The  accompanying  photo  shows  a  Ger- 
man telephone  outpost  in  operation  on  the 
Somme  front.   It  is  one  of  the  first  German 


the  Naval  Reserve.  The  statement  says  in 
part: 

"German  agents,  it  has  now  become  cer- 
tain, have  been  placed  upon  American  mer- 
chant ships  for  the  purpose  of  betraying 


A  30,500  MILE  TELEGRAPH 

CIRCUIT. 

During  the  World's  Series  baseball  con- 
test the  Associated  Press  had  its  entire 
system  of  leased  wires  looped  together  at 
the  various  centers,  so  that  the  sending 
operator  at  the  baseball  grounds  communi- 
cated directly  with  every  newspaper  served 
by  the  association.  The  mileage  of  the  cir- 
cuit was  approximately  30,500  miles,  or  500 
miles  longer  than  that  of  a  year  ago. 


Photo  ©  by  Kadel  and  Herbert 
One  of  the  Few  Recent  German  War  Pictures  to  Reach  the  United  States.    This  Shows 
a  Typical   German  Telephone  Outpost  Near  the   Front  Line  Trenches.     The  Military 
"Telefon  Vorposten"  is  a  Fighter  as  Well  as  Electrician. 


pictures  to  arrive  in  this  country  since 
America's  entry  into  the  war. 

This  photo  shows  only  one  of  the  many 
thousand  German  telephone  outposts  that 
are  being  used  by  the  Kaiser's  fighting 
legions  on  the  Somme  and  other  fronts.  The 
military  telephone  linemen  who  install  and 
maintain  these  front  line  instruments  are 
all  armed  and  often  have  to  fight  for  their 
lives,  as  might  be  expected.  In  other  words 
the  "Telefon  Vorposten"  as  he  is  called,  is 
a  soldier  first  and  a  telephone  expert  after- 
ward. Some  of  these  telephones  are  instal- 
led in  dug-outs  and  shell  holes  even  beyond 
the  front-line  trench. 

It  is  really  wonderful  how  the  men  of  the 
signal  corps  actually  contrive  to  place  their 
listening  posts  right  under  the  noses  of  the 
enemy.  More  often  than  not  the  telephone 
squad  has  to  work  its  way  from  shell  hole 
to  shell  hole,  with  ever-watchful  snipers 
blazing  away  at  them  every  time  they  ex- 
pose their  bodies.  But  the  commanders 
must  know  at  all  times  just  what  is  transpir- 
ing all  along  the  front  and  here  we  have 
our  answer  as  to  the  supreme  necessity  of 
the  telephone  outpost  here  shown. 


SPIES  USING  RADIO  ON  U.  S. 
SHIPS? 

In  a  statement  recently  issued  the  Pa- 
triotic Society,  with  headqarters  in  Wash- 
ington, D.  C,  makes  the  flat  declaration  that 
German  agents  have  been  placed  on  Ameri- 
can merchant  ships  for  the  purpose  of  be- 
traying them  in  the  submarine  zone. 

The  wireless,  it  is  charged,  is  used  for 
this  purpose,  signals  are  flashed  from  port 
holes,  a  smoke  pillar  is  employed  by  stoking 
the  fires  in  a  peculiar  way,  and  at  night  a 
stream  of  sparks  is  substituted  for  the 
smoke  by  day. 

Because  of  the  situation  which  is  declared 
to  exist  the  society  makes  a  plea  for  the 
manning  of  American  merchant  ships  by 


them  when  the  submarine  zone  is  reached. 
These  agents  are  German  seamen,  posing  as 
neutrals,  and  neutral  subjects  in  the  pay  of 
the  Imperial  Government. 

"The  wireless  is  frequently  used  to  sum- 
mon the  U-boat  to  its  prey.  At  night  sig- 
nals are  flashed  from  port  holes.  In  some 
cases  the  fires  are  stoked  in  such  a  way  that 
a  long,  thick  veil  of  smoke  trails  over  the 
horizon  marking  the  way  of  the  ship.  If 
the  passage  is  made  at  night  the  firing  is 
done  in  such  a  way  that  a  shining  trail  of 
sparks  point  out  the  victim  as  clearly  as  if 
a  giant  searchlight  had  been  turned  upon  her. 

"Recently  an  oil  steamer  was  sighted  by 
a  submarine.  At  a  time  when  the  U-boat 
was  still  at  a  distance,  the  fire  crew  deserted 
their  post  in  a  body.  The  men  appeared  on 
deck  with  life-preservers  belted  on,  ready  to 
take  to  the  boats.  An  army  officer  happened 
to  be  on  board.  He  looked  at  the  oncoming 
U-boat,  noted  the  distance  she  was  away  and 
calculated  that  there  was  still  an  opportu- 
nity to  escape.  At  the  point  of  the  pistol 
he  compelled  the  deserters 
to  return  to  the  fire  room 
and  the  tanker  was  saved. 

"The  use  that  is  made 
of  the  wireless  on  ship- 
board, however,  is  giving 
our  navy  men  the  most 
serious  concern.  Besides 
informing  the  submarines 
of  the  vessel's  where- 
abouts the  ship's  wireless 
affords  the  German  'spy 
system  an  opportunity  of 
communicating  informa- 
tion of  importance  from 
the  United  States.  Such 
messages  can  be  sent  with- 
in a  few  hours  after  any 
given  vessel  has  cleared 
from  an  American  port." 

Anyone  having  information  that  would 
help  the  good  work  along  should  write  the 
society. 


A  HANDY  PORTABLE  LIGHTING 
OUTFIT 

Difficulty  is  necessarily  experienced  in 
underground  work  because  of  the  lack  of 
light.  This  is  particularly  true  of  manhole 
work  where  the  only  natural  light  obtain- 
able comes  thru  the  entrance  to  the  man- 
hole from  the  street,  and  the  limited  amount 
of  space  is  such  that  practically  in  every 
position  a  man  works  in  a  manhole  he  is 
bound  to  obstruct  his  own  light.  Because  of 
this  fact  a  good  electric  light  is  most  es- 
sential and  a  portable  light  is  the  only  prac- 
tical one.  The  accompanying  illustration 
shows  a  portable  battery  lighting  outfit  de- 
veloped for  just  such  a  purpose. 

This  set  is  neatly  and  compactly  installed 
in  a  small  steel  black  enameled  box.  The 
equipment  includes  an  Edison  storage  bat- 
tery consisting  of  5  cells  completely  as- 
sembled in  a  tray,  fully  charged,  ready  for 
immediate  service,  together  with  two  prop- 
erly guarded  12  C.P.  lamps  with  reflectors 
and  with  eleven  foot  leads.  One  of  these 
lamps  can  be  used  for  20  hours  on  one  com- 
plete charge  of  the  battery,  constantly  burn- 
ing.   Both  of  them  will  burn  for  ten  hours. 

Due  to  the  use  of  the  Edison  storage 
battery  no  injury  from  overcharging  or 
from  complete  discharging  occurs.  The 
electrolyte  is  a  non-corrosive,  alkaline  solu- 
tion ;  no  acid  being  used.  The  manhole  elec- 
tric lighting  outfit  is  a  portable  unit  and  for 
this  reason  the  question  of  weight  is  most 
important.  The  outfit  shown  can  readily  be 
Handled  by  anyone  and  carried  an  unusual 
distance  without  effort.  The  complete  outfit, 
battery  and  all,  weighs  only  40  pounds. 

The  actual  cost  of  maintenance  and 
operation  is  really  very  small.  The  cost  of 
upkeep  on  one  battery  for  one  year  has  been 
found  to  be  less  than  10  cents.  By  connect- 
ing a  suitable  number  of  batteries  in  series 


For   Lighting    Manholes,   Cable   and    Pipe  Tunnels,   and  a 
Hundred  Other  Places,  This  New  Storage  Battery  Lighting 
Outfit  Will  Prove  Ideal. 


and  figuring  on  a  10  cent  rate  per  K.W. 
hour  for  current  it  costs  less  than  10  cents 
to  fully  charge  each  battery  from  a  com- 
pletely discharged  condition. 


January,  1918 


ELECTRICAL  EXPERIMENTER 


601 


HUGE  ELECTRIC  METER  RECORDS 
250,000  KILOWATTS. 

The  largest  graphic  recording  meter  in  the 
world  is  illustrated  in  the  accompanying  cut. 
It  has  a  capacity  of  250,000  kilowatts  and  is 
installed  in  the  Keokuk  plant  of  the  Mis- 
sissippi River  Power  Company.  To  meter 
the  output  of  the  thirty  three-phase  gen- 
erators used  in  this  plant  required  the  use 
of  thirty  polyphase  meter  elements,  each 
made  up  of  two  single-phase  units.  In  car- 
rying out  the  design  of  this  instrument  the 
desirability  of  using  the  same  general  design 
in  other  instruments  was  borne  in  mind, 
with  the  result  that  the  supporting  frame 
was  made  up  of  three  sections  as  shown, 
each  carrying  ten  polyphase  meter  elements, 
thereby  making  it  possible  to  construct  a 
similar  instrument  of  ten  elements  or  any 
multiple  of  ten  up  to  fifty. 

The  induction  type  of  meter  element  was 
adopted,  after  having  devised  an  element 
capable  of  being  calibrated  mechanically  for 
torque  without  effecting  the  correction  for 
power  factor.  The  moving  element  consists 
of  six  aluminum  vanes,  all  mounted  on  a 
single  staff,  supported  in  such  a  manner  as 
completely  to  eliminate  friction. 

All  connections  are  carried  to  the  top 
of  the  instrument  to  a  circular  terminal 
board  carrying  240  binding  posts,  four  be- 
ing used  for  each  single-phase  meter  ele- 
ment. The  actual  width  of  chart  is  12.5 
in.  (31.8  cm.).   The  charts  used  are  printed 


"Teratuter" — An  Electrically  Operated  Flying  Teacher 


Talking  of  Recording  Electric  Meters  Com- 
pare this  Giant,  With  a  Capacity  of  250,000 
Kilowatts  to  Your  House  Meter.  This  Meter 
Is  as  Tall  as  a  Man  and  the  Largest  Ever 
Built. 

in  twelve-hour  sections  and  fed  at  the  rate 
of  3  in.  (7.6  cm.)  per  hour  over  two  rollers, 
one  of  which  carries  pins  for  driving  the 
paper  and  is  rotated  by  means  of  a  solenoid- 
operated  ratchet  connected  in  the  electric 
clock  system  of  the  plant.  The  indicating 
scale  which  faces  the  system  operator's 
desk  is  illuminated  and  graduated  to  the 
same  range  as  the  chart. 

With  an  instrument  of  this  type  it  is 
possible  to  totalize  the  output  of  a  station 
of  any  capacity  or  a  number  of  stations  or 
systems,  regardless  of  differences  in  fre- 
quencies, voltage  and  whether  or  not  they 
are  in  synchronism,  and  instruments  of  the 
same  type  can  be  built  for  any  number  of 
circuits  from  five  to  fifty. 


American  inventive  ingenuity  has  already 
solved  the  problem  of  speeding  up  the  train- 
ing of  aviators.  Considered  scientifically, 
an  aviator  can  move  his  aeroplane  only  in 


much  expensive  flying  practise  would  be 
dispensed  with.  The  Teratuter  is  operated 
by  a  powerful  blower  driven  by  an  electric 
motor. 


The  Powerful  Electrically  Driven  Blower  Seen  At  the  Extreme  Right  Produces  Strong  Air 
Currents  Which  are  Caused  to  Alternately  Blow  Against  the  Four  "Wings"  of  This  Aviation 
Teaching  Machine  So  As  to  Reproduce  Actual  Flying  Conditions. 


three  dimensions  while  flying : — he  can  point 
it  up  or  down,  or  prevent  it  from  pointing 
up  or  down  which  is  one;  he  can  tilt  it  to 
the  right  or  left,  or  prevent  it  from  so  tilt- 
ing, which  is  two ;  or  he  can  turn  it  to  the 
right  or  left,  or  prevent  it  from  turning, 
which  is  three  and  the  limit  of  his  control. 
From  the  combinations  of  these  three 
movements,  combined  with  the  forces  of  the 
motor  and  gravity,  "flying,"  with  more  or 
less  proficiency,  results. 

The  Teratuter,  as  the  apparatus  is  called, 
was  developed  from  the  notion  that  if  a  man 
could  be  drilled  to  produce  those  identical 
movements  with  the  identical  wheels  and 
levers  that  are  used  on  an  actual  aeroplane, 
to  the  point  where  he  could  do  it  instinct- 
ively with  the  precision  and  speed  of  the  ac- 
complisht  aviator,  and  the  drilling  done  on 
a  dummy  aeroplane  mounted  to  go  thru  a 
full  range  of  the  aeroplane's  movements, 


Most  of  the  more  proficient  of  the  world's 
famous  aviators  attained  their  wonderful 
control  of  the  aeroplane  by  sitting  in  their 
machines,  closing  their  eyes,  and  persist- 
ently operated  their  controls  in  long 
imaginary  flights. 

Aside  from  the  field  value  of  the  Tera- 
tuter, it  can  be  erected  in  college  buildings 
to  accompany  the  theoretical  training  of 
those  who  are  to  become  officers  in  avia- 
tion corps.  The  one  in  the  illustration, 
(the  first  one  invented)  is  an  accessory  of 
a  New  York  flying  institution. 

To  make  the  device  as  realistic  as  pos- 
sible, it  is  operated  by  a  great  volume  of 
comprest  air.  The  inventor,  himself  an 
aviator,  has  adjusted  the  aeroplane  members 
which  produce  or  correct  the  Teratuter's 
motion  to  be  about  equal  to  the  movements 
of  a  real  aeroplane  flying  in  a  40  mile  per 
hour  wind. 


ILLUMINATED    FLAG  PROVIDES 
HANDSOME  DISPLAY. 

Everyone  wants  to  show  his  patriotism 
now.  Everyone  can  now  show  the  colors 
night  and  day  with  this  hand- 
some electric  flag.  The  flag  is 
mounted  on  heavy  board  12  x 
18  inches  with  easel  and  hanger, 
and  is  equipt  with  Mazda  lamps 
and  six  foot  leader  cord.  It 
can  be  put  in  the  window,  the 
doorway  or  a  dozen  other 
appropriate  places  and  provides 
a  good  advertisement  as  well 
as  patriotic  display.  It  is 
particularly  well  adapted  for 
residence  decorations  and  looks 
well  in  the  front  window  of  any 
house  or  apartment. 


Three  thousand  electric  fans  are  to  be 
used  on  the  cargo  handling  ships  which  are 
now  under  construction  for  the  United 
States  shipping  board. 


ONE    TON    OF  METER 
JEWELS. 

One  ton  of  saffires  will  be 
used  during  the  year  1917  in 
one  factory  where  the  jewelled 
bearings  of  electric  meters  are 
made.  The  jewels  are  pur- 
chased in  the  rough  and  are 
put  thru  finishing  and  drilling 
processes  which  require  a  de- 
gree of  skill  comparable  only 
to  that  of  an  experienced 
watchmaker. 


One  of  the  Latest  House  and  Show-Window  Decorations  la 
This  Electrically  Illuminated   Flag.     It  Is  Small  Yet  Dis- 
tinctive and  Attractive. 


602 


ELECTRICAL  EXPERIMENTER 


January,  1918 


Modern  Physics  and  the  Electron 

How  Professor  R.  A.  MILLIKAN,  the  brilliant  American  Scientist,  made  the  "Electron"  visible  and  how  the  electrical 

dimensions  of  the  "Electron"  have  been  measured 


IF  you  have  any  respect  for  my  subject 
or  any  respect  for  me,  you  will  not 
expect  me  to  outline  in  the  space  of  one 
brief  hour  the  work  of  modern  physics. 
It  is  utterly  impossible  to  do,  and  I 
can  say  that  without  affecting  an  inordinate 
egotism. 


modern  civilization  is  the  spirit  of  scientific 
research — a  spirit  which  first  grew  up  in  the 
subject  of  physics,  and  has  spread  from  that 
to  all  the  other  subjects  of  modern  scien- 
tific inquiry. 

That  spirit  has  three  elements.  The  first 
is  a  philosophy,  the  second  is  a  method,  and 


violates  the  most  sacred  duty  of  his  profes- 
sion. This  present  cataclysm  which  has 
set  the  world  back  a  thousand  years  in  so 
many  ways,  has  shown  us  the  pitiful  spec- 
tacle of  scientists  who  have  forgotten  com- 
pletely the  scientific  method,  and  have  been 
controlled  simply  by  prejudice  and  by  pre- 


POWERFUL 
ELECTRIC  FIELD 
IN  HELIUM 'GAS 


>S  CHARGED 
FRICTION 


MOLECULES  %  BOTTOM 
PLATE 


X  RAYS  CAUSE 


MOLECULES  TO 
BE  COME  ELEC 
TRICALLY 


CHARGED  MHO 


TO  JUMP  TOWARD 


TOP  AND  BOT 
TOM  PLATES 


TOP  PLATE 


I  OA/ 5  FROM 
THE  AIR. 


bottom  plate 

electric  all  y 
charged  oil  drop 

CAUSED  TO  Ft  Y  UP  /)ND 
DOWN  BETWEEN 
TWO  PLATES 


Fig.  1.  If  We  Have  Two  Plates  With  an  Electric  Field  Between 
Them  and  Nothing  Else  but  a  Monatomic  Gas  Like  "Helium," 
Then  This  Gas  Remains  Stagnant  When  the  Field  Is  Thrown  On. 
A  Beam  of  X-Rays  Shot  Between  the  Plates,  However,  Causes 
Some  of  the  Molecules  to  Become  Electrified  and  to  Jump  Toward 
the  Plates,  This  Effect  Being  Measurable. 


©  E.  P.  Co. 

Fig.  2.  Using  Two  Plates  Charged  With  10,000  Volts,  It  Became 
Possible  to  Isolate  a  Single,  Minute,  Charged  Oil  Drop  and  to  Alter- 
nately Move  It  Up  and  Down  by  Switching  the  Electric  Field  On 
and  Off.  This  Oscillating  Particle  Was  Found  to  Attract  Ions 
From  the  Air,  Signaling  Each  Capture  to  the  Observer  by  the 
Change  in   Its  Speed   in  the  Field. 


The  spirit  of  modern  science  is  something 
relatively  new  in  the  world's  history,  and 
I  want,  as  an  introduction  to  the  main  ad- 
dress, to  give  an  analysis  of  what  it  is.  I 
want  to  take  you  up  in  an  aeroplane  which 
flies  in  time  rather  than  in  space,  and  look 
down  with  you  upon  the  high  peaks  that  dis- 
tinguish the  centuries,  and  let  you  and  me 
see  together  what  is  the  distinguishing  char- 
acteristic of  this  century  in  which  we  live. 
I  think  there  will  be  no  question  at  all,  if 
you  get  far  enough  out  of  it  so  that  you  can 
see  tbe  woods,  without  having  your  vision 
clouded  by  the  proximity  of  the  trees,  that 
the  thing  which  is  characteristic  of  our 


Fig.  3.  Actual  Photographs  of  the  Tracks 
of  "a" — Particles  Shooting  Thru  the  Air. 
We  Now  Know  That  These  "a" — Particles 
Do  Not  Penetrate  the  Air  After  the 
Manner  of  a  Bullet,  i.e.,  by  Pushing  the 
Molecules  of  Air  Aside,  bur  Rather  That 
They  Actually  Shoot  Thru  All  the  Mole- 
cules of  Air  Which  They  Encounter.  An 
"a" — Particle  Would  Have  to  Make  About 
500,000  Such  Passages  Thru  Molecules  in 
Traversing  2.75  Inches  of  Air. 


the  third  is  a  faith,  said  Prof.  R.  A.  Millikan 
recently  before  the  American  Institute  of 
Electrical  Engineers  at  New  York.  Look 
first  at  the  philosophy.  I  say  that  is 
new  for  the  reason  that  all  primitive  peo- 
ples, and  many  that  are  not  primitive,  have 
held  a  philosophy  that  is  both  animastic  and 
fatalistic.  Every  phenomenon  which  is  at 
all  unusual  or  for  any  reason  not  immedi- 
ately intelligible  used  to  be  attributed  to  the 
direct  action  of  some  invisible  personal  be- 
ing. Witness  the  peopling  of  the  woods 
and  streams  with  spirits  by  the  Greeks ;  the 
miracles  and  possession  by  demons  of  the 
Jews ;  the  witchcraft  manias  of  our  own 
Puritan  forefathers,  only  two  or  three  hun- 
dred years  ago. 

Now,  that  a  supine  fatalism  results  from 
such  a  philosophy  is  to  be  expected,  for  ac- 
cording to  it  everything  that  happens  is  the 
will  of  the  gods,  or  the  will  of  some  more 
powerful  beings  than  ourselves.  And  so, 
in  all  the  ancient  world,  and  in  much  of  the 
modern  also,  three  blind  fates  sit  down  in 
dark  and  deep  inferno  and  weave  out  the 
fates  of  men.  Man  himself  is  not  a  vital 
agent  in  the  march  of  things,  he  is  only  a 
speck,  an  atom  which  is  hurled  hither  and 
thither  in  the  play  of  mysterious,  titanic 
uncontrollable  forces. 

Second,  as  to  the  method  of  science,  it  is 
a  method  practically  unknown  to  the  ancient 
world ;  for  that  world  was  essentially  sub- 
jective in  all  its  thinking  and  built  up  its 
views  of  things  largely  by  introspection. 
The  scientific  method  on  the  other  hand  is  a 
method  which  is  completely  objective.  It 
is  the  method  of  the  working  hypothesis 
which  is  ready  for  the  discard  the  very 
minute  it  fails  to  work.  It  is  the  method 
which  believes  in  a  minute,  careful,  wholly 
dispassionate  analysis  of  a  situation ;  and 
any  physicist  or  engineer  who  allows  the 
least  trace  of  prejudice  or  preconception  to 
enter  into  his  study  of  a  given  problem 


conception.  (Referring  to  the  World-War.) 

In  the  mystical,  fatalistic  ages  which  pre- 
ceded, electricity  was  simply  the  agent  of 
inscrutable  Providence;  it  was  Elijah's  fire 
from  Heaven  sent  down  to  consume  the 
enemies  of  Jehovah ;  or  it  was  Jove's  thun- 
derbolt hurled  by  an  angry  God ;  and  it  was 
just  as  impious  to  study  so  direct  a  mani- 
festation of  God's  power  in  the  world  as  it 
would  be  for  a  child  to  study  the  strap  with 
which  he  is  being  punished,  or  the  mental 
attributes  of  the  father  who  is  behind  the 
strap.  It  was  only  one  hundred  and  fifty 
years  ago  that  Franklin  sent  up  his  famous 
kite,  and  showed  that  these  thunder  bolts 
were  identical  with  the  sparks  which  he 


Fig.  4.  Here  Are  Actual  Photographs  of 
"b" — Particles  Shooting  Thru  Air.  Cut  At 
Right  Shows  Track  of  Very  High  Speed 
"ti"-Ray.  This  Particular  Particle  Shot 
Thru  On  an  Average  as  Many  as  10,000 
Atoms  Before  It  Came  Near  Enough  to 
an  Electronic  Constituent  of  Any  One  of 
These  Atoms  to  Detach  It  From  Its  Sys- 
tem and  Form  an  Ion.  This  Shows  That 
Electronic  Constituents  of  Atoms  Can  Oc- 
cupy but  a  Very  Small  Fraction  of  the 
Space  Inclosed  Within  the  Atomic  System. 


January,  1918 


ELECTRICAL  EXPERIMENTER 


603 


could  draw  on  a  winter's  night  from  his 
cat's  back. 

And  at  the  end  of  the  nineteenth  century 
there  were  many  of  us  physicists  and  en- 
gineers who  thought  that  all  the  great  dis- 
coveries had  been  made.  It  was  a  common 
statement  that  this  was  so.  I  heard  it  pub- 
licly made  in  1894,  and  yet  within  a  year 
of  that  time  I  happened  to  be  present  in 
Berlin  at  the  meeting  of  the  Physical  So- 
ciety at  which  Rontgen  showed  his  first 
photographs,  and  since  that  time  we  have 
had  a  whole  new  world,  the  very 
existence  of  which  was  undreamed 
of  before,  opened  up  to  our 
astonished  eyes. 

We  have  found  a  world  of 
electrons  which  underlies  the 
world  of  atoms  and  molecules 
with  which  we  had  been  familiar, 
and  the  discoveries  in  that  world 
have  poured  in  so  rapidly  within 
the  last  twenty  years  that  there 
are  no  two  decades  in  human  his- 
tory that  compare  at  all  with  them 
in  the  rapidity  of  the  advance. 
And  these  discoveries  have  been 
made  too  for  the  most  part  by 
groups  of  men  interested  merely 
in  finding  out  how  nature  works. 
They  have  been  made  almost 
exclusively  by  college  professors  ; 
and  for  ten  years  they  remained 
the  exclusive  property  of  these 
professors.  What  has  happened  in 
the  last  ten  years  ?  The  industrial 
world  has  fallen  over  itself  in  the 
endeavor  to  get  hold  of  these  ad- 
vances, and  by  their  aid  it  has 
increased  ten-fold  the  power  of 
the  telephone,  it  has  obtained  four 
or  five  times  as  much  light  as  we  got  a  few 
years  ago  out  of  a  given  amount  of  electrical 
power,  it  has  developed  new  kinds  of  trans- 
formers the  existence  of  which  was  never 
dreamed  of  before — all  these  things  are 
coming  now,  it  is  not  in  the  distant  future, 
that  we  are  going  to  find  the  applications ; 
we  have  found  in  the  last  five  years  a  great 
quantity  of  them,  and  how  many  more  are 
going  to  come,  no  man  call  tell. 

Finally,  before  launching  upon  the  sea  of 
recent  discovery,  I  wish  to  make  one  more 
remark  about  the  method  of  science,  namely 
this :  The  progress  of  science  is  almost 
never  by  the  process  of  revolution.  You 
see  a  great  deal  in  your  newspaper  headings 
about  revolutionary  discoveries.  They  al- 
most never  happen !  Thus  when  the  atom 
was  found  not  to  be  an  ultimate  but  a  divis- 
ible thing,  there  was  no  revolution,  there 
was  not  a  single  law  that  had  to  be  given 
up.  We  had  simply  opened  up  a  new  field, 
tapt  a  new  lead,  found  an  unexplored 
region,  a  sub-atomic  region,  and  all  that 
was  above  it  remained  just  exactly  as  it  had 
been,  and  no  chemist  had  any  occasion  to  be 
disturbed,  for  the  chemist's  laws  were  just 
as  precise  as  they  had  been  before.  Some- 
times we  do  indeed  find  that  we  have  gen- 
eralized too  far,  and  that  some  law  which 
we  had  supposed  to  be  of  universal  applica- 
tion is  limited  in  its  scope,  but  this  does  not 
alter  the  fact  that  the  growth  of  science  is 
in  general  by  a  process  of  accretion,  almost 
never  by  that  of  revolution.  Once  in  a 
while  we  have  something  revolutionary,  but 
not  often. 

We  may  aptly  characterize  the  physics  of 
the  last  twenty  years  as  the  physics  of  atom- 
ism, and  the  first  discovery  on  my  list  is  the 
recent  verification  of  the  adumbrations  of 
the  Greeks  regarding  the  atomic  and  the 
kinetic  theories — the  proof  that,  as  Demo- 
critus  had  imagined  500  B.  C,  this  world 
does  indeed  consist,  in  every  part  of  it,  of 
matter  which  is  in  violent  motion. 

Up  to  within  six  years  there  were  not  a 
few  distinguished  scientists  who  withheld 
.  their  allegiance  even  from  these  atomic  and 
kinetic  theories  of  matter.    The  most  illus- 


trious of  them  was  Professor  Wilhelm  Ost- 
wald,  but  in  the  preface  to  a  new  edition 
of  his  Outlines  of  Chemistry  he  now  says 
frankly : 

"I  am  convinced  that  we  have  recently 
become  possest  of  experimental  evidence 
of  the  discrete  or  grained  nature  of  matter 
for  which  the  atomic  hypothesis  sought  in 
vain  for  hundreds  and  thousands  of  years. 
The  isolation  and  counting  of  gaseous  ions 
on  the  one  hand.  .  .  .  and  on  the  other  the 
agreement  of  the  Brownian  movements  with 


Fig.  5. — The  Precision  Apparatus  Used  by  Prof.  Millikan  At 
the  University  of  Chicago  Laboratory  For  Determining  the 
Physical  and  Electrical  Constants  of  the  "Electron."  The 
Condenser  Plates  (See  Figs.  1  and  2,  Also  Fig.  6  Below)  Were 
Made  With  Surfaces  Polished  Optically  to  Such  an  Accuracy 
That  the  Error  Was  Less  than  One  Part  in  10,000. 


kinetic  hypothesis.  .  .  .  justify  the  most 
cautious  scientist  in  now  speaking  of  the 
experimental  proof  of  the  atomic  theory 
of  matter.  The  atomic  hypothesis  is  thus 
raised  to  the  position  of  scientifically  well- 
founded  theory." 

I  think  you  all  know  what  the  Brownian 
Movements  are  but  I  wish  especially  to  call 
attention  to  the  fact  that  this  advance  was 
made  not  by  a  practical  man,  but  by  a  man 
who  never  did  any  experimental  work  in 
his  life,  Einstein,  a  mathematician,  a  man 
who  was  capable  of  analyzing  a  theory  and 
predicting  results,  and  the  experimental- 
ists have  checked  those  results.  The  re- 
sults consists  in  predicting  how  far  a  given 
particle  that  you  can  see  in  an  ultra  micro- 
scope will  drift  in  a  given  time,  and  our 
own  experiments  have  checked  this  pre- 
diction to  within  one-half  per  cent.  It  is 
that  sort  of  evidence  that  has  convinced 
Professor  Ostwald  of  the  correctness  of 


Fig.  6. — Sectional  View  of  the  Millikan  Appa- 
ratus For  Measuring  the  "Electron."  Tem- 
perature is  Kept  Constant  by  Oil  Tank  G. 
Oil  Spray  Is  Produced  by  Atomizer  A,  the 
Droplet  Entering  Between  Plates  M  and  N, 
Thru  Tiny  Hole  in  Top  Plate.  Light  From 
an  Arc  Lamp  Passes  Thru  Heat  Absorbers 
W  and  D,  Enters  Thru  Glass  Window  g,  and 
Illuminates  Droplet  P.  Additional  Ions  Are 
Produced  About  P,  by  X-rays  From  the  Bulb 
X.  A  Special  Microscope  Enables  Close  Ob- 
servation of  the  Droplet,  As  Prof.  Millikan 
ExDlains  In   His  Work — "The  Electron." 


the  new  kinetic  and  the  atomic  theories. 

The  second  advance  is  the  proof  of  the 
divisibility  of  the  atom,  a  proof  which  grew 
out  of  the  discovery  of  X-rays.  Let  me 
tell  you  how.  If  you  have  here  two  plates 
(Fig.  1.)  with  an  electric  field  betwen  them, 
and  nothing  else  but  a  monatomic  gas  like 
helium,  then  it  is  found  that  when  the  field 
is  thrown  on  the  helium  is  perfectly  stag- 
nant, but  when  a  beam  of  X-rays  is  shot 
between  the  plates  some  of  the  molecules 
become  electrically  charged  and  begin  to 
jump,  some  of  them  toward  the 
upper  plate  and  some  toward  the 
lower  plate,  where  their  presence 
can  be  detected  by  an  electrical 
measuring  instrument.  What  does 
that  show?  It  shows  that  the 
thing  which  we  call  an  atom  has 
electrical  charges  as  its  constitu- 
ents ;  and  the  history  of  the  last 
twenty  years  in  physics  has  con- 
sisted pretty  largely  in  determin- 
ing what  are  the  properties  of 
these  electrical  constituents. 

The  third  is  the  discovery  of 
radio-activity,  which  occurred  just 
a  little  after  the  discovery  of  X- 
rays.  And  here  again  we  found 
matter  doing  things  we  had  never 
dreamed  it  was  doing  viz :  shoot- 
ing off  from  itself  both  negatively 
and  positively  charged  particles, 
the  negatives  with  a  speed  which 
may  approach  close  to  the  velocity 
of  light,  186,000  miles  per  second, 
and  positives  with  a  speed  of  one- 
tenth  of  that,  or  18,000  miles. 
The  fact  that  such  speeds  could  be 
imparted  to  projectiles  of  any 
kind  was  undreamed  of  twenty 
years  ago. 

The  fourth  discovery  that  I  wish  to  men- 
tion is  the  discovery  of  the  atomicity  of 
electricity,  the  proof  that  the  thing  we  call 
electricity  is  built  up  out  of  a  definite  num- 
ber of  specks  of  electricity,  all  exactly  alike, 
and  that  what  we  call  an  electrical  current 
consists  simply  in  the  journey  along  the  con- 
ductor of  these  electrical  specks,  which  we 
may  call  with  perfect  justice  definite  ma- 
terial bodies.  Now,  I  can  give  you  in  just 
a  word  the  proof  of  that  statement.  There 
are  half  a  dozen  ways  in  which  it  could 
be  approached.  I  will  mention  the  one  with 
which  I  am  most  familiar,  because  it  is  the 
particular  proof  which  we  worked  out  at 
our  (University  of  Chicago)  laboratory. 

We  took  these  plates  with  a  field  of  10,000 
volts  between  them,  with  a  little  hole  in  the 
top  plate,  and  we  blew  an  oil  spray  above 
the  top  plate  so  as  to  get  an  electrically 
charged  body  just  as  small  as  we  could,  for 
we  expected  that  the  frictional  process  in- 
volved in  blowing  the  spray  would  charge 
the  drops,  which  it  was  found  to  do.  (Fig. 
2.)  We  let  one  of  those  drops  come  into  the 
space  between  the  plates  and  then  moved 
it  up  and  down  by  an  electrical  field,  throw- 
ing on  the  field  as  it  came  close  to  the  bot- 
tom plate,  and  throwing  it  off  as  it  ap- 
proached the  upper  one,  and  so  we  kept  that 
oil  drop  going -up  and  down  between  the 
plates,  in  the  hope  that  it  would  capture 
some  of  the  ions  which  we  knew  existed  in 
the  air,  put  there  by  radium  or  other 
agencies.  The  drop  met  our  fullest  expec- 
tations as  a  police  officer  capturing  ions 
frequently  and  signaling  the  fact  of  each 
capture  to  the  observer  by  the  change  in 
its  speed  in  the  field. 

For  the  oil  drop  is  an  electrically  charged 
body,  and  in  a  given  field  it  moves  with  a 
definite  speed.  If,  however,  it  captures  an 
ion,  its  charge  increases  or  decreases,  and 
hence  its  speed  increases  or  decreases.  If 
the  charges  on  ions  are  all  alike,  then  we 
can  only  get  one  particular  change  in  speed. 
If  the  charge  that  is  already  upon  it,  put 
there  by  the  frictional  process,  is  built  up 
{Continued  on  page  643) 


604 


ELECTRICAL  EXPERIMENTER 


January,  1918 


NOW 


FOR  THE  ELECTRICAL 
RAZOR. 


You  Sign  Your  Name  on  This  Time  Clock 


We  are  truly  living  thru  an  electrical 
age  and  there  is  a  never-ceasing  demand 
for  new  inventions  driven  by  electricity. 
Here  we  are  offered  the  electric  razor  that 
is  said  to  remove  the  beard,  without  the 
pull,  with  a  smoothness  that  cannot  be 
equaled. 


The  Electric  Razor  Is  the  Newest  Novelty. 
Its  Plug  Terminal  Fits  Any  Lamp  Socket.  It 
Combines  a  Massage  and  a  Smooth  Shave  At  the 
Same  Time.    It  Actually  "Cuts"  the  Hair  Off. 


To  the  busy  man,  when  time  means 
money  as  well  as  to  the  man  who  cannot 
shave  himself,  this  machine  will  appeal. 
It  can  be  used  without  electricity,  the  same 
way  as  any  razor. 

The  construction  of  the  electric  razor 
is  very  simple:  A  vibrating  motor  is  sta- 
tioned in  the  handle  wound  with  enameled 
wire  which  is  water-proof.  The  head  is 
made  of  the  best  treated  steel. 

With  the  new  electric  safety  razor  the 
blade  vibrates  1,200  times  a  minute  and 
actually  cuts  the  hair  instead  of  pulling; 
and  there  is  no  need  of  the  necessary  side 
stroke  that  must  be  used  in  the  common 
safety  razor.  The  new  razor  has  the  ef- 
fect of  both  a  shave  and  massage,  leaving 
the  face  with  the  most  pleasant  feeling 
that  is  not  possible  without  the  vibrating 
effect  here  produced. 

To  shave  with  the  electric  razor  is  the 
same  process  as  shaving  with  any  razor, 
except  that  you  connect  the  cord  with  a 
light  socket  and  turn  on  the  switch  when 
beard  is  lathered.  The  device  runs  with 
alternating-current,  but  the  makers  are 
perfecting  a  direct-current  type. 


A  new  electric  time  clock  recently  pat- 
ented and  now  being  placed  on  the  market 
is  illustrated  herewith.  The  invention  in 
question  is  a  new  time  recording  device  that 
"cannot  be  beat."  We  are  all  accustomed 
to  seeing  the  big  clocks  with  their  hundreds 
of  card  racks,  in  working  establishments, 
these  racks  being  an  entirely  cumber- 
some and  unnecessary  item.  Besides, 
who  hasn't  heard  of  the  numerous  ideas 
and  schemes  employees  evolve  to  de- 
fraud the  company  by  having  a  friend 
ring  up  their  number  for  them. 

Then  again  big  corporations  keep  tabs 
on  their  hundreds  of  workers,  whose 
time  is  only  a  small  consideration,  yet 
allow  the  big  directors  and  various  of- 
ficials to  come  and  go  at  leisure,  whose 
time  may  be  many  times  more  valuable 
and  expensive  to  the  firm  ! 

Therefore,  it  is  of  value  to  know  and 
be  sure  that  important  persons  in  your 
employ  are  punctual  and  arrive  on  time 
to  transact  your  business,  otherwise 
many  an  important  order  may  be  lost 
by  an  executive  being  late. 

Wherefore  we  have  the  "Signograph" 
perfected  by  Mr.  H.  Hartman,  of  New 
York.  ' 

The  machine  itself  is  of  small  and  at- 
tractive construction  taking  but  little 
space  on  the  wall  or  desk,  measuring  only 
9  inches  long,  7  inches  wide  and  3  inches 
deep.  It  is  made  entirely  of  metal,  black 
enameled.    Its  heart  is  an  eight-day  clock 


records ;  these  consist  of  a  continuous  strip 
of  paper  3  inches  wide,  which  shows  at  a 
glance  the  signatures  thereon  with  accurate 
day,  hour  and  minute  printed  opposite  each 
signature. 

The  instrument  has  no  complicated 
mechanism  to  get  out  of  order  and  is  con- 
structed along  lines  that  avoid  every  shock 
or  sudden  vibration  which  could  affect  the 
clock.  Not  only  all  this,  but  the  clock  can 
be  fitted  with  an  automatic  electrical  device 
that  will  register  the  time  when  a  person 
opens  or  unlocks  the  door  of  an  establish- 
ment, thereby  showing  the  exact  hour  and 
minute  at  which  the  responsible  party  ar- 
rived. 

Taking  the  device  as  a  whole  it  appears 
to  be  a  100%  efficiency  machine,  and  a  ne- 
cessity to  almost  any  class  of  business.  By 
referring  to  the  photos  a  clear  idea  of  the 
entire  mechanism  may  be  obtained  and  will 
prove  that  this  machine  can't  be  beat. 


JAPANESE   SUPERSTITIONS  AND 
THE  TELEPHONE. 

The  Japanese,  like  many  Americans,  be- 
lieve there  is  luck  in  certain  numbers,  and 
are  willing  to  go  to  great  lengths  to  gain 
the  protection  of  these  lucky  symbols. 

A  single  figure  telephone  in  Tokio  sells 
for  from  800  to  1,000  yen  ($390  to  $490)  a 
year.  The  luckiest  number  in  the  estimation 
of  business  is  eight,  because  the  character 
for  it  spreads  downward  and  suggests  the 
idea  of  gathering  prosperity.  Number  753 
is  also  believed  to  be  a  lucky  number,  be- 
cause children  are  presented  at  Shinto 
shrines  on  their  third,  fifth  and  seventh 
birthdays.  Indeed,  odd  numbers,  are  lucky. 
Three-figure  numbers  are  not  objectionable, 
if  they  are  as  easy  to  remember  as  123  or 
555. 

The  most  unlucky  numbers  are  42  and  49. 
because  the  former  may  be  pronounced 
"shini,"  which  means  "to  die,"  and  the  latter 
may  be  pronounced  "shiku,"  which  means 
"death"  and  "suffering."  Therefore,  it  is 
said  that  those  numbers  are  avoided  by 
individuals  and  generally  taken  by  govern- 
ment officers,  schools,  police  stations,  and 
other  invincible  institutions. 


The  Time  Clock  That  Can't  Be  Beat.    It  Auto- 
matically Registers  the  Day,  Hour  and  Minute 
That    You    "Sign"    Your    Name.      It    Can  Be 
Electrically  Connected  to  Store  Doors,  Etc. 


movement  attached  to  the  mechanism. 

Attached  to  the  clock  is  a  large  wheel 
on  which  are  the  figures  for  the  hours 
of  the  day  and  night.  Arabic  figures 
show  the  time  A.  M.  and  Roman  figures 
designate  the  time  P.  M. 

Being  named  the  "Signograph,"  it 
means  exactly  as  its  name  implies.  In 
the  front  of  the  device  is  a  small  glass 
door.  When  the  person  desires  to 
record  time,  he  or  she  simply  opens  the 
door.  Immediately  the  door  is  open  a 
record  is  made  inside  the  machine  by 
a  device  on  the  door  hinge  which  presses 
the  paper  against  the  type  wheel  con- 
taining the  hour  numerals ;  then  the  per- 
son signs  his  or  her  signature,  as  the 
case  might  be,  closes  the  door,  moves  the 
paper  up  and  the  trick  is  done!  Very 
simple  and  yet  effective,  as  a  written  evi- 
dence is  obtained  of  the  party  being  on 
time. 

The  eight-day  clock  movement  can  be 
wound  from  the  outside,  while  the  ma- 
chine can  be  opened  by  one  possessing 
the  key  for  the  purpose  of  changing 


WIRELESS  COURSE  AT  UNIVER- 
SITY OF  WISCONSIN. 

Wireless  telegraphy,  with  special  applica- 
tion to  war  service,  has  now  been  made  a 
regular  course  at  the  University  of  Wis- 
consin. A  number  of  students  worked  in- 
dependently in  the  university  radio  station 
last  year  and  during  the  summer  session  a 
course  for  operators  was  given,  but  univer- 
sity credit  for  the  work  is  given  for  the  first 
time  this  year. 

The  radio  station  at  the  university  is 
one  of  the  few  to  be  left  in  operation 
after  the  declaration  of  war  because  war 
research  is  being  carried  on  with  the  sta- 
tion apparatus.  Lieutenant  Taylor,  radio 
communication  superintendent  at  the  Great 
Lakes  naval  training  station  in  Illinois, 
recently  visited  the  Wisconsin  station  and 
made  a  number  of  tests.  An  officer  from 
the  naval  station  will  be  in  the  university 
this  year  to  carry  on  tests  with  the  Great 
Lakes  station. 

The  mathematical  theory  of  electricity 
and  magnetism  as  related  to  wireless 
telegraphy  will  be  given  careful  study  in 
the  new  course  as  well  as  a  detailed  study 
of  the  apparatus  itself.  The  students  will 
also  have  a  chance  to  become  expert 
operators. 

A  review  of  general  physics,  a  special 
study  of  transformers  and  oscillating  cur- 
rents and  their  application  to  sending  and 
receiving  apparatus,  as  well  as  a  careful 
study  of  special  forms  of  sending  sets,  will 
be  included  in  the  work.  The  course  will 
continue  thruout  the  year. 


It  is  estimated  that  this  year's  business 
in  electric  ranges  will  be  in  the  neighbor- 
hood of  $3,000,000. 


Interior  of  New  Time  Clock,  Showing  Record 
of  Signature  on  Clockwork  Driven   Paper  Roll 
and  "Time"  Typewheel  At  Left. 


January,  1918 


ELECTRICAL  EXPERIMENTER 


605 


Novel  Applications  of  The  Dictograph 


PEOPLE  will  not  cease  wondering  at  the 
seemingly  marvelous  and  uncanny  way 
conversations  are  picked  up  by  the  Dic- 
tograph, the  original  supersensitive  micro- 
phone. 

In  its  secret  service  adaptation,  it  is  used 
by  the  U.  S.  Department  of  Justice,  the 
Army  and  Navy,  and  governmental,  state 
and  municipal  police  authorities  for  secur- 
ing the  evidence  wanted,  when  any  other 
method  would  have  failed.  Numerous  cases 
might  be  cited,  the  one  most  prominent  in 
the  public  eye  being  the  recent  dynamiting 
cases  of  the  McNamaras. 

Then  again,  in  business  its  application  in 
interior  inter-communication  has  proved  a 
big  help.  By  the  aid  of  a  "master  station"  a 
busy  executive  is  able  to  hold  instant  com- 
munication with  his  stenographer,  super- 
intendent or  factory,  hold  conferences, 
know  exactly  what  is  going  on  and  never 
have  to  leave  his  desk ;  or  he  may  walk 


ing  of  men  for  the  flying  corps  and  their 
work  on  the  battlefield  has  been  hampered 
thru  lack  of  adequate  means  of  commu- 
nication between  the  pilot  and  observer — 
thereby  necessitating  them  to 
return  to  the  ground  before 
they  could  give  any  detailed  or 
elaborate  directions  to  one 
another  or  make  changes  in 
their  plans. 

This  new  system  consists  of 
a  special  headgear  which  is 
strapt  over  the  regular  helmet. 
In  the  back  of  the  same  is 
set  a  dictograph  so  that  it  is 
always  in  the  vertical  po- 
sition ;  from  this  a  tube  leads 
downward  to  a  specially  con- 
structed mouth-piece,  to  be 
strapt  in  place  over  the  mouth. 

A  stop-cock  regulates  the 
sonority  of  the  voice  which  is 
allowed  to  reach  the  dic- 
tograph— a  special  cable 
is  run  between  the  two 
seats  and  to  which  both 
operators  attach  their 
plugs.  It  is  believed  that 
this  method  will  supersede 
all  previous  efforts  in  this 
line.  Those  who  have 
never  been  up  in  a  flying 
machine  of  modern  type, 
which  speeds  along  at  a 
velocity  of  from  60  to  120 
miles  per  hour  at  times, 
have  no  real  conception  of 
the  physical  action  on  the 
aviator.  His  face  is  often 
distorted  bv  the  terrific  air 
pressure — his  cheeks  are 
pushed  inward  until  they 
are  hollow.  And  often- 
times he  can  just  barely 
speak,  owing  to  the  severe 
cold,  which  fairly  petrifies 
the  skin  and  flesh.  This  condition  was 
mentioned  to  the  writer  by  a  member 
of  the  Royal  Flying  Corps  of  Canada. 

The  interior  view  of  the  limousine 
shows  the  dictograph  serving  as  a 
means  of  communication  between  the 
occupants  of  the  car  and  the  chauffeur, 
without  the  necessity  of  anybody  mov- 
ing their  position  or  holding  speaking 
tubes.  Just  press  the  button— talk  in 
a  natural  tone — and  the  chauffeur  hears 
every  word  clearly  and  distinctly.  This 
type  of  equipment  will  be  found  on 
almost  every  car  of  note  this  season, 
among  which  may  be  named  the  fol- 
The  Loud  Speaking  Telephone  or  Dictograph  Has  lowing  representative  ones:  Packard, 
Found  Its  Way  Into  the  Motor-Car  World.  Many  pni_  Cadillac  HiiHsnn  Piprrp  Arrnw 
of  the  Best  Cars  Are  Now  Regularly  Equipt  With  !r;°le'  ^aa'lla-C,  riudson,  Fierce-Arrow, 
This  Convenience  (See  Arrow),  Permitting  One  to  Wmton,  Chalmers  and  Willys-Knight. 

Give  Directions  to  the  Chauffeur  Without  Moving.      r>  u„„„    *u  j.    ■  ±  j 

a      rernaps   the  most   interesting  and 


and  skilful  man  to  operate  them.  I  show 
herewith  drawing  of  a  "magnetic"  hat  die 
which  dispenses  with  the  press  entirely.  It 
is  composed  of  the  usual  two  members,  the 


U.  S.  Aviators  Are  Being  Supplied  With  the  New  Dicto- 
graph Here  Shown,  for  Carrying  on  Conversation  With 
a  Second  Officer,  While  in   Flight.     The  Engine  Noise 
and  Wind  Make  It  Difficult  to  Talk  Otherwise. 


lower  and  upper  die.  The  lower  die  is 
made  of  non-magnetic  metal  and  is  pro- 
vided with  one  or  more  magnets,  the  respec- 
tive poles  of  which  pierce  the  frame  of  the 
die  and  even  out  smoothly  with  the  outer 
surface;  the  upper  die  being  of  iron,  when 
placed  over  the  lower  die  acts  like  an  arma- 
ture, and,  in  becoming  attracted,  presses  and 
heats  the  material  to  be  shaped. 


around  the  room,  file  papers,  etc.,  and  still 
be  able  to  converse  with  whoever  is  at  the 
other  end  just  as  if  they  were  in  the  room. 

But  by  far  the  greatest  boon  to  mankind 
of  this  invention  has  been  its  adaption  in 
aiding  deaf  people  to  hear,  thereby  making 
them  more  efficient  and  useful,  and  also 
lessening  the  chance  of  accidents. 

To  church  and  theatregoers  it  has  also 
proven  of  great  merit — heretofore  deaf  peo- 
ple could  only  see  the  show  or  sit  dumbly 
in  church,  but  by  this  application  of  the 
dictograph  they  are  now  enabled  to  secure 
seats  which  are  equipt  with  receivers  ad- 
justable to  each  individual  and  hear  every- 
thing that  is  said,  not  to  mention  the  en- 
joyment of  the  music  and  singing. 

In  the  first  illustration  may  be  seen  the 
very  latest  application  of  the  microphonic 
principle — to  help  Uncle  Sam  win  this  war 
with  flying  machines.   Heretofore  the  train- 


novel  application  of  the  dictograph  is 
the  installation  in  a  very  popular  Broadway 
rendezvous — the  "Palais  Royal."  In  the  ball- 
room, where  diners  and  dancers  wile  away 
their  hours,  the  management  has  had  placed 
around  the  pillars  carefully  concealed  horns. 
Near  the  orchestra,  a  number  of  special 
dictographs  are  placed,  with  wires  leading 
to  the  cabaret  performers'  dressing  rooms. 
When  the  music  commences  it  is  carried 
to  the  dressing  rooms  and  the  artists  sing 
into  transmitters  which  are  connected  with 
the  horns  in  the  dining  room,  causing  the 
singing  to  come  from  a  seemingly  mysteri- 
ous source,  much  to  the  amazement  of  the 
patrons. — George  Holmes. 


A  "MAGNETIC"  HAT  DIE. 
By  John  P.  Buckley. 

The  present  hat-making  machines  are 
operated  by  hand  and  require  a  very  strong 


A  New  Hat-Die  in  Which  the  Moving  Form 
is  Pulled  Against  the  Fixt  Plate  by  Means 
of  Electro- Magnets. 

A  girl  may  operate  several  of  these  ma- 
chines or  dies  at  one  time. 


606 


ELECTRICAL  EXPERIMENTER 


January,  1918 


OUT-LEVITATING  BACHELET! 

While  in  Manchester,  England,  recently  I 
came  across  considerable  local  enthusiasm 
for  gas-driven  vehicles.  I  heard  of  one 
optimist  who  is  working  night  and  day  to 
solve  the  problem  with  "comprest  gas."  His 
efforts,  however,  pale  before  those  of  a 
super-gas  merchant  who  believes  in  the  flex- 
ible holder  on  the  roof ;  the  chief  plank  in 
his  platform  is  that  when  the  holder  is  full 
there  is  a  levitating  effect  which  takes  a  lot 
of  the  weight  of  the  vehicle  off  the  tires 
and  increases  their  mileage.  Shades  of 
Bachelet,  what  next ! 


A   MYSTIC   WHIRLING  SHOW 
WINDOW  ATTRACTION. 

A  distinct  and  startling  novelty  shown  at 
the  recent  Electrical  Show   held   at  New 


DISHWASHING  BY  ELECTRICITY. 

Who  wants  to  wash  dishes?  Answer — 
Nobody.  Therefore  and  hence  we  have 
with  us  today  the  electric  dishwasher  here 
portrayed. 

Under  the  basket  containing  the  dishes  as 
shown  in  the  picture,  is  a  square  shaft  to 
which  are  attached  propellers  or  scoops. 
This  shaft  is  connected  directly  to  an  elec- 
tric motor  by  means  of  a  spur  gear.  As  the 
shaft  is  revolved  at  approximately  600  re- 
volutions per  minute,  the  water  is  thrown 
with  great  force  upward  and  around  the 
dishes  in  the  basket.  Every  surface  is 
cleansed  and  every  trace  of  food  particles, 
grease  and  accumulations  of  any  kind  re- 
moved. Breakage  is  practically  impossible 
for  the  reason  that  the  hot  water  comes  in 
contact  with  all  surfaces,  inside  and  outside, 
at  the  same  time  and  the  expansion  is  fairly 
equalized. 

There  has  been  considerable  agitation  in 
recent  months  concerning  the  dangers  of 
careless  dishwashing  and  authorities  agree 
that  the  only  thoroly  safe  method  is  the 
machine  method  where  practically  boiling 
water  can  be  used. 

This  electric  dishwasher  is  of  very  rigid 
construction.  The  body  is  24  gage  steel 
—all  joints  and  corners  are  welded — the 
legs  are  standard  1  inch  wrought  iron  pipe, 
securely  welded  to  the  angle  iron  frame 
work — the  propellers  are  riveted  to  the 
shaft  and  all  parts  are  rust-proofed.  The 
electric  motor  is  enclosed  with  the  housing 


Mother  and  the  Girls  May  Now  Rejoice,  fop 
Here's  the  Genie  That  Washes  the  Soiled 
Dishes  By  Electricity.    And  It  Never  Wants 
a  Day  Off. 


which  the  picture  shows,  protecting  it  from 
splashing,  and  also  safe-guarding  the  chil- 
dren. The  finish  of  the  machine  is  baked- 
on  white  enamel. 


WIRELESS  LOST  BATTLE. 

Great  events  turn  on  very  small  incidents. 
It  is  now  given  out  that  the  reason  the  Ger- 
mans were  defeated  in  the  battle  of  the 
Marne  was  largely  because  one  of  the  com- 
manding officers  did  not  know  enough  about 
wireless  telegraphy  to  know  that  the  big 
instrument  on  Eiffel  tower  in  Paris  was 
picking  up  his  messages  as  fast  as  he  sent 
them  back  to  German  headquarters.  As  a 
result  the  French  army  was  enabled  to  make 
preparations  which  turned  the  tide  of  battle 
against  the  Germans  on  the  Marne.  The 
German  general  was  an  expert  fighter  but 
he  had  not  kept  up  with  the  modern 
progress  of  inventive  genius  in  the  develop- 
ment of  wireless  telegraphy,  and  conse- 
quently because  of  this  lack  of  knowledge  it 
is  now  given  out  officially  that  the  battle 
was  lost  to  the  Germans.  (A  very  pretty 
tale,  but  incredible. — Editor.) 


Pens,  Boxes,  Figures,  Everything,  Stick  to 
This  Mysterious  Cylinder  and  Whirl  Around 
It  in  a  Fascinating  Manner. 

York  was  a  whirling  display  which 
attracts  electrically  every  variety  of  small 
object.  Toy  automobiles  tour  its  circular 
surface,  miniature  yachts  ride  its  metal  sea 
with  even  keel,  handkerchiefs,  papers  of 
pins,  everything  it  is  possible  to  purchase 
in  a  ten-cent  store,  cling  to  its  electrified 
surface  and  attract  the  eye  of  the  passers- 
by.  H.  J.  Herberts,  inventor  of  this  selling 
device,  placed  his  first  contract  with  a  Ger- 
man firm  just  before  the  war.  As  a  result 
the  first  10,000  made  were  confiscated  by  the 
German  Government  for  the  brass  and  cop- 
per they  contained,  and  the  inventor  had 
to  come  to  America  and  begin  all  over  again. 
The  machine  is  fully  protected  by  patents. 

This  remarkable  advertising 
device  consists  of  electrically 
driven  apparatus  inclosed  in  a 
plated  metal  jacket  and  dome, 
upon  which  the  goods  are  made 
to  revolve  without  any  visible 
means  of  suspension  while  the 
external  part  of  the  apparatus 
is  quite  stationary.  No  hooks 
or  wires  of  any  sort  are  em- 
ployed. The  approximate  di- 
mensions of  the  device  are  24 
in.  high  and  9  in.  in  diameter. 
Articles  of  unusual  shape  take 
peculiar  lines  of  travel  about 
the  smooth  metal  cylinder,  roll- 
ing over  and  over  as  they  go. 


THE  ELECTRIC  MICROSCOPE  IN- 
CUBATOR CLEVER  INVENTION. 

For  those  desiring  to  make  a  special  study 
of  Micro-organisms  at  blood  temperature 
for  any  length  of  time,  there  is  now  avail- 
able a  specially  constructed  incubator,  in 
which  the  entire  microscope  may  be  placed. 
The  illustration  shows  how  this  is  accom- 
plisht.  To  place  the  microscope  in  the  in- 
cubator the  two  sliding  doors  on  the  top 
are  pulled  out  and  afterwards  pushed  back 
until  they  fit  tight  against  the  microscope. 
Both  sides  are  provided  with  hand  holes, 
which  enable  the  operator  to  manipulate  the 
microscope  in  the  ordinary  way.  When  not 
in  use  the  hand  holes  are  closed  by  metal 
slides. 

The  Incubator  is  made  of  insulating 
material  and  has  a  removable  plate  glass 
front.  The  heating  element  consist  of 
special  wire  units,  distributed  inside  the 
cabinet.  It  is  controlled  in  the  usual  way 
by  a  clever  adjustable  electro-thermostat. 

This  Incubator  is  particularly  well  adapted 
for  universities  and  research  laboratories. 
It  is  used  to  advantage  in  watching  develop- 
ments of  embryos  of  animal  parasites  and 
also  in  watching  the  growths  of  normal  and 
abnormal  tissues.  It  is  convenient  in 
bacteriological  and  zoological  research  work 
and  in  research  work  on  blood. 


RADIO  TELEPHONY  IN 
JAPAN. 

The  Institute  of  Radio  En- 
gineers held  a  meeting  on 
Wednesday  evening,  November 
7,  in  the  Engineering  Societies 
Building,  New  York,  at  which 
Mr.  Eitaro  Yokoyama,  engi- 
neer  of  the  Ministry  of  Com-  w\ 
munications,  Tokyo,  Japan,  pre- 
sented a  paper  on  "Some 
Aspects  of  Radio  Telephony 
in  Japan."  The  paper  contained 
an  interesting  summary  of  the 
litflp  known  wnrk  whiVh  has  An  Electric  Incubator  for  Maintaining  the  Entire  Mlcro- 
iittie-known  worK  wtncn  nas  scope  at  a  Constant  Temperature.  A  Necessary  Refine- 
been  done  in  this  field  in  Japan,   ment  Where  Live  Organisms  or  Tissue  are  to  Be  Studied, 


January,  1918 


ELECTRICAL  EXPERIMENTER 


607 


NEW  ELECTRIC  STOVE  RESEM- 
BLES "FIRELESS  COOKER." 

A  new  electric  stove  built  on  the  order 
of  the  heat-retaining  "tireless  cooker"  is 
shown    in    the    illustration    herewith  and 


The  "Flreless  Cooker"  Principle  Is 
Incorporated  in  This  Electric  Stove. 
You  Start  with  620  Watts  for  a  Few 
Moments,  Then  Switch  on  the  40 
Watt  Heater,  the  Latter  Doing  the 
Real  Cooking. 


operates  on  40  watts,  (same  as  your  lamps). 

Place  any  food  you  wish  in  the  compart- 
ment, and  close  the  cover.  Set  the  clock 
for  a  few  minutes  current,  to  heat  up  the 
calorator.  At  the  expiration  of  that  time 
the  clock  will  turn  off  the  620  watt  heater 
and  turn  on  the  40  watt  heater.  The  cook- 
ing heat  will  then  remain  at  cooking  tem- 
perature until  you  wish  to  use  your  food. 

You  can  cook  an  average  meal  for  less 
than  two  cents,  its  makers  claim. 

These  new  electric  cookers  are  finished 
in  blue  enamel  with  nickel  trimmings  and 
are  made  of  iron ;  lined  with  heavy  gage 
aluminum.  Each  cooker  is  provided  with 
one  3-quart  circular  kettle  and  two  2j^- 
quart  semi-circular  kettles,  all  made  of 
heavy  gage  aluminum.  Thus  you  cook  a 
whole  meal — meat,  potatoes  and  two  vege- 
tables— at  one  time. 

The  heat  calorator  in  the  bottom  of  the 
cooker  is  made  with  two  heating  elements. 
One  consumes  620  watts  (same  as  an  elec- 
tric iron)  and  the  other  40  watts  (same  as 
one  electric  light). 


AUTOMATIC  LIGHT  CONTROLLER 
FOR  FLIVVERS. 

The  automatic  light  cpntroller  here  shown 

is  placed  on 
the  dash  un- 
der the  hood 
and  requires 
n  o  adjust- 
ment or  ma- 
nipulation by 
the  operator 
of  the  car. 

By  means 
of  a  moving 
armature 
which  is 
automat- 
ically  pulled 
under  a 
mag  netized 
field  as  the 
car  speeds  up  and  dropt  out  as  the  speed 
decreases,  the  lights  are  kept  practically 
constant  thruout  the  range  of  speed  of  the 


An  Automatic  Controller  for 
Regulating  Light  from  A.  C. 
Dynamo  System  of  the  Ford 
Car. 


car.  It  is  intended  for  use  on  Ford  cars  in 
which  an  alternating  current  magneto  is 
used. 

The  controller  operates  on  the  impedance 
or  reactance  principle.  The  field  is  wound 
with  suitable  magnet  wire  and  connected  in 
series  with  the  circuit  of  the  magneto  which 
furnishes  current  to  the  lamps.  The  cur- 
rent of  the  magneto  passing  thru  this  wind- 
ing energizes  the  field  magnetically  in  direct 
proportion  to  the  strength  of  the 
magneto  current  which  is  gov- 
erned by  the  speed  of  the  car. 
The  armature  rotates  in  this  mag- 
netic field  and  is  so  adjusted  that 
when  the  speed  of  the  car  is  below 
ten  miles  per  hour  the  field  has  not 
sufficient  strength  to  attract  it  and 
consequently  no  impedance  is  of- 
fered to  the  current,  and  the  lights 
burn  at  full  voltage  and  candle- 
power.  As  the  speed  of  the  car  is 
increased  the  magnetic  strength  of 
the  field  is  increased,  and  the 
armature  is  drawn  under  it  in 
exact  proportion  to  the  increased 
speed  and  voltage.  Impedance  is 
now  set  up  between  the  field  and 
armature  in  the  same  proportion, 
which  reacts  on  the  current  and 
voltage  generated  by  the  magneto 
and  keeps  the  voltage  and  candle 
power  of  the  lamps  practically  con- 
stant thruout  the  range  of  speed 
of  the  car,  as  the  greater  the  speed 
the  greater  the  magnetic  strength 
of  the  field,  the  greater  the  movement  of 
the  armature  under  the  field  and  the  greater 
the  impedance  set  up  between  the  field  and 
armature. 


pull  on  the  cord  will  extend  it,  allowing  it 
to  unreel  to  its  full  length  whenever  de- 
sired. There  is  no  strain  on  the  cord  while 
it  is  connected,  as  the  table  reel  locks  auto- 
matically in  any  position  to  which  you  may 
desire  to  set  it,  and  can  be  released  by  a 
touch  of  the  finger. 


SERVICE  OVERSEAS!  !  ! 

Electrical  men  are  wanted  for  early  ser- 
vice overseas.  The  men  in  the  front  line 
trench  need  the  help  and  cooperation  of 
skilled  men  back  of  the  lines,  and  electrical 
men  are  wanted  at  once  for  the  Enlisted 
Ordnance  Corps,  National  Army. 

Uncle  Sam  is  calling  on  our  trade  to  come 
across  and  help  his  fighting  men.  There  is 
a  lot  of  work  to  be  done  over  there,  and 
the  call  has  gone  out  for  electricians  and 
electrical  men  between  the  ages  of  18  and  40 
who  want  to  do  their  bit,  and  who  know 
their  job. 

Modern  war  is  a  tremendous  business, 
and  the  army  that  wins  is  the  army  which 
has  the  best  equipment  and  the  best  men. 
The  men  are  over  there  now — they  are 
ready  to  go  ahead,  but  they  still  need  ex- 
perts in  our  line  to  repair  and  maintain  their 
equipment.  There  is  a  fine  chance  for  every 
man  who  wants  to  help. 

Write  to  the  Chief  of  Ordnance,  War  De- 
partment, Washington,  D.  C. 


Herel    The  Electric  Tea  Wagon  Simply  Had 
to  Come. 


ELECTRICALLY  WARMED  AUTO 
STEERING  WHEEL. 

This  electrically  warmed  hand  wheel  for 
autos  may  be  applied  to  any  car  and  it 
operates  practically  without  cost,  drawing 
but  a  slight  amount  of  current,  about  as 
much  as  does  one  of  the  headlights  from 
the  storage  battery  when  in  use.  When  not 
in  use  there  is  nothing  but  the  switch  but- 
ton to  show  that  the  heating  attachment 
is  present — as  all  the  mechanism  is  em- 
bedded in  the  composition  of  the  wheel  with 
the  wires  self-contained  within  the  steering 
column.  The  wheel  is  made  either  in  Bake- 
lite  or  Condensite. 

To  outside  appearances  the  rim  is  identi- 
cal with  the  plain  model  steering  wheel, 
for  the  reason  that  the  heating  coils  are 
self  contained  in  the  composition.  The 
simple  pushing  of  the  small  button  located 
on  the  spider  of  the  wheel  turns  the  heat 
on  or  off.  The  heating  wires  are  cast 
within  the  rim,  concealed  from  view.  Thus 
the  driver  is  not  conscious  of  the  heating 
feature  until  he  presses  the  button,  when 
the  wheel  begins  to  warm  his  hands.  This 
steering  wheel  is  one  of  the  best  models 
yet  developed.    It  always  retains  its  hand- 


THE    ELECTRIC    TEA  WAGON 
AWAITS!  YOUR  LADYSHIP. 

It  is  often  desirable  to  have  an  electric 
heater  for  teapot,  chafing  dish  or  toaster 
at  the  hostess'  hand  and  to  meet  this  re- 
quirement we  have  the  new  electric*  tea 
wagon  here  illustrated.  At  least  two  de- 
vices may  always  be  heated,  such  as  an 
electric  percolator  and  a  chafing  dish  or 
toaster. 

The  designer  has  incorporated  a  feature 
of  considerable  merit  in  connection  with  the 
wiring  of  this  electric  tea  wagon,  in  the 
form  of  an  adjustable  table  reel  installed 
under  the  lower  shelf.  This  is  a  spring- 
actuated  device,  operating  as  simply  as  a 
spring  roller  window  shade,  and  it  carries 
ten  feet  of  silk  covered  lamp  cord  with  an 
attachment  plug  at  the  end.  When  the  tea 
wagon  is  not  in  use  this  attachment  plug 
may  be  withdrawn  from  the  wall  recep- 
tacle, whereupon  the  adjustable  reel  will 
automatically  take  up  the  slack  so  that  it 
does  not  trail  on  the  floor  or  be  wound  up 
and  stowed.    On  the  other  hand,  a  slight 


A  New  Electrically  Warmed  Steering  Wheel 
Which  Has  the  Heating  Wires  Embedded  In 
the   Moulded  Rim. 

some  appearance,  not  becoming  shabby  in 
a  few  months  as  varnished  wooden  types 
are  wont  to  do.  It  operates  from  the  car 
battery. 


608 


ELECTRICAL  EXPERIMENTER 


January,  1918 


The  Chemical  Exhibition  at  New  York 

By  ALBERT  W.  WILSDON 


THE  exhibits  at  the  Third  National 
Exhibition  of  Chemical  Industries, 
held  at  Grand  Central  Palace,  at 
New  York  City  during  the  week  of 
September  24,  1917,  was  very  inter- 
esting and  instructive  both  for  the  layman 
and  the  engineer. 


which  serves  to  attract  all  the  good  con- 
ducting ore  to  one  side  while  the  poor  con- 
ductors are  past  over  the  drum  to  a  different 
container. 

A  complete  line  of  pyrometers,  including 
both  recording  and  optical  types  was  shown, 
the  latter  being  of  special  interest,  possess- 


Fig.  4.    Tool  Hardening  with  Modern  Electric  Furnaces.    The  Furnace  at  the  Right  Is 
Specially  Adapted  for  Hardening  Carbon  Steels  and  Pre-heatlng  High  Speed  Steels.  The 
Furnace  at  the  Left  Is  for  Hardening  High  Speed  Steels.    The  Electric  Furnace  Is  Ideal 
for  All  Such  Work  as  the  Heat  Can  Be  Very  Closely  Regulated. 


Electricity  of  course,  played  a  very  con- 
spicuous role,  and  many  new  appliances 
were  exhibited  which  had  been  improved 
upon  by  its  use. 

Among  the  exhibitors  displaying  electric 
devices  were  the  following: 

The  Anaconda  Copper  Mining  Company 
exhibited  products  showing  various  steps  in 
the  reduction  of  copper,  commencing  with 
the  Butte  ores,  to  the  commercial  refined 
copper  shapes  such  as  ingots,  wire  bars, 
slabs,  cakes,  etc.  Also  an  interesting  and 
extensive  exhibit  of  the  important  by-prod- 
ucts obtained  by  the  electrolytic  refining  of 
copper,  such  as  copper  sulfate,  nickel  sul- 
fate, white  arsenic,  selenium  in  all  its  allo- 
tropic  modifications,  tellurium,  silver,  gold, 
platinum,  and  palladium. 

The  Condensite  people  displayed  molded 
electrical  insulation  as  applied  to  automobile 
starting,  lighting,  and  ignition  apparatus, 
moulded  commutators,  high  tension  insula- 
tors, U.  S.  Navy  wireless  insulators  and 
lamp  sockets,  electrical  condensers,  and 
miscellaneous  insulation,  condensite  mold- 
ing preparations,  impregnating  enamels  and 
cements,  molded  condensite  as  used  in  disc 
phonograph  records,  moving  picture  ma- 
chines vending  machines,  fire  extinguishers, 
etc. 

Then  there  was  a  complete  5  H.P.  indus- 
trial steam  plant  in  actual  operation.  This 
miniature  plant  embodies  an  automatic 
boiler-feeding  system,  auto  lifting  and  non- 
return steam  traps.  A  coil  kettle  is  heated 
to  a  definite  temperature  by  the  boiler,  and 
the  condensation  is  returned  to  the  boiler — 
100  per  cent  efficiency  is  claimed. 

A  new  electrostatic  separator,  Fig.  1,  was 
demonstrated,  and  in  which  concentrations 
and  separations  of  mixed  ores  are  produced 
by  static  electricity.  This  device  embodies 
an  electrically  charged  electrode  as  shown, 


ing  both  accuracy  and  simplicity.  In  con- 
nection with  the  recording  instruments  a 
red,  white  and  blue  light  system  of  indicat- 
ing variation,  high  or  low,  of  the  furnace 
temperatures  from  a  fixt  value  was  ex- 
hibited. Apparatus  for  determining  the 
conductivity  of  electrolytes  was  shown,  in- 
cluding the  Vreeland  oscillator  for  produc- 
ing a  high  frequency  E.  M.  F.  of  pure  sine 
wave.  The  new  design  of  the  Burrows  per- 
meameter  for  magnetic  measurements,  and 
a  useful  type  of  hydrogen  electrode  was 
also  demonstrated. 

Technical  thermometers  of  all  descrip- 
tions were  there,  including  thermometers 
for  laboratory  and  research  work,  and  for 
acid  manufacturers,  also  the  Pcntane  and 
toluol  thermometer,  for  low  temperatures, 
the  toluol  to  minus  100 
deg.  C :  the  Pentane  to 
minus  200  deg.  C. 

An  eastern  electrical 
instrument  company  ex- 
hibited a  new  line  _  of 
pyrometers  and  electrical 
precision  instruments.  A 
very  interesting  booklet 
was  distributed  by  this 
concern  which  contained 
considerable  information 
regarding  high  and  low 
temperatures.  Fig.  2 
gives  a  very  instructive 
curve  of  the  estimated 
number  of  laws  and  facts 
known  experimentally, 
which  was  taken  from 
this  booklet.  In  this  chart 
temperature  elevation  is 
indicated  by  the  height 
of  a  vertical  line,  and  the 
makers  have,  to  an  ap- 
proximation, represented 


by  distances  measured  to  the  right  of  this 
line  the  number  of  facts  and  laws  of  matter 
about  which  we  have  gathered  true  experi- 
mental evidence.  Thus  there  is  obtained  a 
curved  line  bounding  the  Region  of  Experi- 
mental Evidence.  All  outside  this  curve 
belongs  to  the  field  of  imagination  and 
speculation,  and  may  properly  be  called  the 
Region  of  Pure  Surmise.  The  former 
region  is  large  when  compared  with  the 
inner  small  Region  Known  To  The  Ancients 
— which  the  philosophers  of  antiquity  could 
have  drawn  to  represent  the  knowledge  of 
their  day.  The  Region  of  Pure  Surmise 
extends  beyond  all  assignable  limits,  and 
investigation  of  this  Region  is  an  aim  and 
problem  of  modern  industrial  research.  Its 
investigation  is  possible  because  a  very  large 
portion  of  it  lies  within  the  limits  of  pro- 
ducible and  measureable  temperatures. 

The  same  concern  exhibited  one  of  the 
very  latest  adjuncts  to  science  in  the  form 
of  a  high-frequency  induction  electric 
furnace.  This  device  is  shown  at  Fig.  3, 
and  was  developed  by  Prof.  Northrup  of 
Princeton  University,  for  use  in  special 
work.  The  outfit  illustrated  at  Fig.  3  is  of 
the  vacuum  type  with  a  rating  of  20 
kilowatts. 

This  high  frequency  induction  furnace 
presents  a  radical  departure  from  usual  fur- 
nace practise,  and  embodies  the  first  em- 
ployment of  oscillatory  currents  for  the 
generation  of  heat  and  production  of  tem- 
perature. By  reason  of  the  highly  effective 
induction  possible  without  the  interlinkage 
of  a  magnetic  with  an  electrical  circuit,  cur- 
rents can  be  set  up  in  the  containing  crucible 
in  the  case  of  a  non-conducting  melt,  or  in 
the  melt  itself  if  the  same  has  sufficient 
conductance  to  permit  the  flow  of  currents. 
No  iron  is  used.  Thus  it  is  possible  to  raise 
the  temperature  of  a  melt  in  a  crucible  until 
its  resistance  becomes  low  enough  to  permit 
the  generation  of  heat  in  the  substance  itself 
(as  in  the  case  of  melting  glass),  after 
which  the  temperature  producible  is  limited 
only  by  the  durability  of  the  insulation  and 
refractory  container. 

Since  this  furnace  operates  by  induction, 
conditions  of  the  melting  chamber  may  be 
controlled  perfectly.  Thus  it  is  possible  to 
produce  temperatures  exceeding  1600°  C  in 
a  partial  vacuum  or  pressure,  with  any  con- 
ceivable atmosphere,  and  if  desired,  without 
the  contaminating  influence  of  carbon.  The 
furnace  works  on  a  two-phase  commercial 
circuit  (60  cycles  frequency),  220  volts,  with 
balanced  load  at  unity  or  slightly  leading 
power  factor. 

Time  was  when  the  tool-maker  and  ma- 


Fig.  3.  The  Very  Latest  Thing  in  Electric  Furnaces — the 
Northrup  High  Frequency  Vacuum  Type.  This  Outfit  Is  Rated 
at  20  Kilowatts.   No  Iron  Is  Used  and  It  Operates  by  Induction. 


January,  1918 


ELECTRICAL  EXPERIMENTER 


609 


chinist  thought  that  the  gas  furnace  repre- 
sented the  last  word  in  such  devices, 
especially  for  tool  hardening  and  treating. 
But  now  the  electric  furnace  has  come  to 
the  front.  The  furnace  shown  at  Fig.  4  is 
being  used  to  harden  tools,  reamers,  taps, 
etc.  It  is  also  being  used  for  hardening 
precision  tools  where  it  is  required  to  pro- 
duce a  number  of  different  pieces  of  steel 


Crushed  Ore 

(C  n '  ■  '  ''' ''''' 

ft 

// 

floc.T 

tiwero/s 

Poor  Conductors 

t?ood  cwt/oc/oss 

Fig.  1.  Magnetic  Ore  Separators  are  Quite 
Common — But  Here  Is  an  "Electrostatic"  Ore 
Separator.  The  Charged  Electrode  Attracts 
the  Good  Conductors  So  That  They  Fall  Into 
a  Separate  Compartment  as  Shown. 

to  do  duplicate  work.  Another  use  to  which 
this  furnace  is  put  is  the  hardening  of  ball- 
bearing thrusts.  It  is  widely  employed  also 
for  the  proper  tempering  of  steel  magnets, 
particularly  small  ring-shaped  magnets  such 
as  used  in  telephone  receivers,  compasses, 
and  other  precision  and  measuring  instru- 
ments. The  electric  furnace  is  susceptible 
of  very  accurate  control,  the  heat  being 
readily  regulated  to  within  a  few  degrees 
of  the  desired  value.  With  improvements 
in  design  these  apparatus  have  been  brought 
to  a  high  state  of  efficiency  and  cost  no  more 
to  run  than  other  types. 


Recording  thermometers,  pyrometers  and 
temperature  regulators  held  the  interest  of 
many.  A  new  development  was  shown  in 
the  "multipyrograph"  for  recording  six 
different  temperatures  on  one  chart,  em- 
ploying only  one  electric  galvanometer. 

Electrical  apparatus  of  particular  interest 
to  chemists  were  shown,  including  motors, 
starters,  oil  switches,  circuit-breakers, 
meters  and  transformers.  A  laboratory  line 
of  apparatus  was  also  exhibited  including 
electric  stoves,  hot  plates,  water  heaters, 
fans  and  air  pumps.  A  number  of  Bakelite- 
Micarta  gears  were  shown.  Bakelite- 
Micarta  is  the  only  non-metallic  gearing 
material  that  is  self  supporting  and  in  most 
cases  neither  bushings  nor  flanges  are 
needed.  A  Thury  regulator  was  shown, 
which  regulates  the  temperature  of  electric 
furnaces  automatically. 

The  sponsors  of  "Bakelite"  displayed 
numerous  forms  of  Bakelite  products, 
moulding  mixtures,  varnishes,  lacquers, 
enamels,  cements,  transparent  and  colored, 
in  sheet,  rod,  tube  and  special  forms. 

Dr.  L.  H.  Bakeland,  the  well-known  in- 
ventor of  Bakelite,  and  gaslight  photo- 
graphic papers,  and  member  of  the  Naval 
Consulting  Board,  gave  a  very  interesting 
lecture  regarding  the  dystuff  industry  under 
the  heading  of  a  paper  "The  Future  of 
Chemical  Industry  in  the  United  States." 

Exhibitors  of  American  made  dyestuffs 
were  the  center  of  attraction  and  many 
remarkable  shades  of  colors  were  shown 
which  compared  favorably  with  those  which 
were  imported  from  Germany  before  the 
war.  Indeed,  the  exhibits  of  the  large 
manufacturing  concerns  demonstrated  how 
this  country  had  past  from  a  position  of 
absolute  dependence  upon  foreign  sources 
of  supply  for  both  the  intermediate  and 
finished  dyestuffs  to  one  of  potential  in- 


dependence, as  regards  both,  in  less  than 
eighteen  months !  To-day  there  are  more 
than  ninety  manufacturers  of  crudes  and 


PRODUCTION 

AND 

MEASUREMENl 


HIGHER 
TEMPERATURES 


Fig.  2.  An  Interesting  Temperature 
Chart  Which  Shows  Graphically  All 
We  Know  About  This  Subject.  The 
Shaded  Area  Indicates  Relative 
Known  Facts  at  Each  Temperature. 
At  6,000°  C.  We  Know  But  Little,  at 
Becomes  Evident. 

intermediates,  and  about  eighty  manufac- 
turers of  artificial  products. 


War  Address  by  A.  I.  E.  E.  President-elect,  E.  W.  Rice,  Jr.* 

(EXCERPTED) 


IT  GIVES  me  great  pleasure  to  meet  you 
here  to-night  and  to  be  thus  introduced 
as  your  President-Elect.  I  thank  you, 
and  thru  you,  all  the  members  of  our  great 
Institution,  for  the  honor  which  you  have 
conferred  upon  me  in  selecting  me  to  be, 
for  a  time,  your  official  leader  and  chief 
servant.  I  hope  I  may  have  the  strength, 
the  ability  and  the  opportunity  to  render 
such  service  as  to  justify,  in  some  measure, 
your  confidence.  I  fully  appreciate  that, 
with  such  a  great  honor,  is  coupled  an 
equally  great  responsibility  and  I  value  the 
position  as  an  opportunity  to  be  of  service 
to  you,  and  thru  you,  to  our  country. 

No  body  of  men  can  get  together  at  the 
present  time  without  soon  discussing  the 
subject  of  the  war,  which  is  uppermost  in 
everyone's  mind. 

The  war  is  the  one  dominating  factor  in 
the  world  life  and  thrusts  itself  before  our 
thoughts  whether  we  wish  it  or  not.  We 
are  in  the  war  at  last  and  will  remain  in 
it  to  the  end.  Whether  it  shall  be  a  bitter 
end  or  a  bright  end  will  depend  largely 
upon  ourselves,  as  it  is  now  our  war. 

It  has  been  stated  many  times  that  mod- 
ern war  was  largely  a  question  of  mechanics 
and  engineering,  a  statement  with  which 
we  must  all  agree.  It  is  self-evident  that 
engineering  must,  therefore,  take  a  leading 
and  dominant  position  in  the  war  work. 
Now  the  electrical  engineer  stands  for  about 
the  latest  thing  in  engineering  development ; 

*  Mr.  Rice  is  president  of  the  great  General 
Electric  Co.,  and  his  suggestions  are  of  particular 
significance  at  this  time  of  national  stress. 


his  activities  embrace  practically  all  other 
fields  of  engineering,  being,  so  to  speak, 
the  last  word  in  engineering.  The  electrical 
engineer  must,  therefore,  realize  that  this 
is  his  war  in  a  very  personal  and  particular 
sense. 

War  calls  for  supreme  sacrifices  and  the 
deepest  devotion,  but  it  also  demands  some- 
thing more  difficult  to  give,  and  that  is 
work.  War  may  be  said  to  be  the  per- 
sonification of  work,  not  only  individual 
work,  but  especially  organized  and  disci- 
plined work, — disagreeable,  dirty,  heart- 
breaking, backbreaking,  nerve-racking  work, 
but  always  work.  No  nation  of  loafers  ever 
won  a  war.  Other  things  being  at  all  equal, 
that  nation  or  people  who  are  willing  to 
work  the  hardest  will  surely  win  the  vic- 
tory. Now  I  wish  to  point  out  that  the 
enemy  we  are  fighting  is  recognized  as  the 
most  industrious  organization  in  the  world. 
Our  enemy  has  prepared  for  war  for  fifty 
years  and  has  been  working  with  ever- 
increasing  energy  ever  since  the  war  started 
three  years  ago.  We  made  no  adequate 
preparation  during  all  this  time  and  there- 
fore started  with  a  fearful  handicap  of 
lost  time  and  lost  opportunities.  We  must 
not  delude  ourselves  that  our  enemy  is  ex- 
hausted, but  remember  that  he  has  the 
advantage  of  a  flying  start.  We  must  ac- 
celerate at  an  incredible  rate  if  we  are  to 
get  our  war-motor  going  fast  enough,  soon 
enough  to  catch  up. 

Now,  properly  understood,  the  fact  that 
no  single  great  invention  is  likely  to  be 
made  which  will  win  the  war,  is  no  cause 


for  discouragement.  It  does  not  mean  that 
theie  will  be  no  improvement,  no  new  in- 
ventions, no  new  methods  devised  and  put 
into  effect.  It  simply  means  that  we  must 
not  wait  for  the  miracle  which  will  never 
appear,  but  get  to  work  and  energetically 
take  advantage  of  all  present  knowledge. 
We  must  survey  the  field,  get  at  all  the 
facts,  carefully  determine  our  plans  and 
then  proceed  to  put  them  into  practical  exe- 
cution. 

Take  for  example  the  matter  of  shipping. 
This  perhaps  presents  the  greatest  imme- 
diate problem  of  the  war,  frightfully  com- 
plicated as  it  is  by  the  submarine.  I  feel 
sure  that  it  can  be  successfully  solved,  if 
we  are  content  to  solve  it  by  the  simple, 
common-sense  methods  used  by  engineers 
and  successful  business  men  in  the  ordi- 
nary course  of  business.  The  problem  must 
first  be  carefully  investigated,  all  available 
data  quickly  obtained  and  checked,  and  all 
new  conditions  considered,  after  which  a 
broad-gaged,  well  considered  plan,  or  plans, 
can  be  formulated,  criticised  and  then  put 
into  effect. 

Of  course  it  is  elementary  to  say  that 
we  must  provide  shipping  in  enormous 
quantities  to  replace  that  destroyed  and  to 
provide  for  increased  demands.  It  is  evi- 
dent that  time  is  the  essence  of  the  prob- 
lem. We  must,  therefore,  build  the  great- 
est tonnage  in  the  shortest  time.  The  ships 
must  be  manned  and  navigated  to  their  des- 
tination and  the  most  efficient  methods  pro- 
vided for  docking,  unloading  and  loading. 
(Continued  on  page  648) 


610 


ELECTRICAL  EXPERIMENTER 


"TOO  LATE" 

By  CHARLES  S.  WOLFE 
The  Story  of  a  Successful  Relay  That  Was  Unsuccessful 


THE  clock  over  my  instrument  table 
gave  a  reading  of  10:30  P.  M.  The 
air  had  been  particularly  dead  all 
evening  and  I  was  a  trifle  bored.  I 
pried  my  ears  loose  from  the  Holt- 
zer-Cabots,   laid    them    (the    'phones,  of 
course,  you  simp)  on  the  table  gently,  and 
arose  to  throw  my  lightning  switch. 

But  I  didn't  quite  get  away  with  it.  Be- 
fore I  reached  the  window  I  heard  a  faint 
squeak  from  the  table.  I  knew  who  it  was, 
all  right;  Jimmy  Hooven,  the  only  other 
amateur  in  town.  Jimmy  did  his  ether 
blasting  with  a  full,  round  kilowatt,  and  a 
kilowatt  at  a  half  mile  gives  forth  an  easily 
readable  signal,  brother !  It  is,  in  fact,  quite 
audible. 

1  hastily  donned   

the  receivers,  threw 
Jimmy  a  trifle  off 
tune  for  my  ear 
drum's  sake,  and 
discovered  that  he 
was  calling  me. 

As  soon  as  my  lit- 
tle one-inch  coil  had 
given  him  a  wheezy 
"G.  A.,"  Jimmy  told 
me  that  he  had  just 
received  a  message 
from  Ashheap,  Ohio, 
for  a  party  who  lived 
nearer  to  me  than  to 
him.  Would  I  deliv- 
er it? 

Would  I  ?  The  one 
ambition  of  my 
wireless  career  up 
until  that  fateful 
night  had  been  to  be 
an  accessory  to  a 
real,  honest-to-good- 
ness  relay  message, 
either  before,  after, 
or  during  the  act. 
Countless  times  I 
had  pictured  myself 
striding  up  to  a  door 
and  saluting  the  as- 
tounded and  awed 
householder  with  a 
matter  -  of  -  fact 
"Wireless  message 
for  you,  sir."  And 
here  was  opportu- 
nity staring  me  in 
the  face. 

I  assured  Jimmy  at 
the  rate  of  twenty- 
two  of  five  letters 
each  that  nothing  would   give  me  more 
pleasure,  and  the  instant  I  got  my  antennae 
switch  over  he  handed  me  this : 
H.  Peck, 

Sknnkton,  Pa. 
Before  lighting  the  kitchen  fire, 
look  in  the  oven.    Billy  sometimes 
sleeps  there. 

Maria  Peck. 
The  preamble  gave  the  office  of  origin  as 
9  B.U.G.,  and  as  I  copied  it  down  I  hastily 
scrawled  in  "Received  at  3  N.U.T.  Boy! 
That  message  sure  looked  like  the  real 
article. 

Jimmy  said  he'd  wait  around  until  I  found 
out  whether  there  was  to  be  an  answer  or 
not,  and  I  heard  him  wailing  C.Q.  plain- 
tively in  an  effort  to  find  company  as  I  tore 
off  the  'phones  and  prepared  to  hop  to  it. 

I  hastily  donned  an  overcoat,  pulled  a 
muffler  around  my  neck,  clapt  a  derby 
on  my  turret  (I  may  say  right  here  that  I 
hatted  in  haste  to  regret  at  leasure),  jammed 
the  received  message  in  my  pocket  together 


with  a  few  blank  forms,  in  case  there  was 
to  be  a  reply,  and  hied  me  forth  to  deliver 
the  thing  to  its  consignee. 

It  was  SOME  evening.  It  was  January 
overhead  and  January  under  foot.  About 
two  inches  of  damp  treacherous  snow  cov- 
ered a  coating  of  inherently  fickle  ice. 
Little  two-inch  blocks  of  snow  collided 
continually  with  my  face. 

I  guess  I  had  walked — or  rather  slid — 
about  two  blocks  at  a  rapid  pace  before  the 
great  white  light  broke  thru  my  shell- 
proof  skull.  Skunkton  is  a  town  of  about 
30,000  souls,  men,  women,  and  politicians. 
The  telegram  was  addrest  to  H.  Peck, 
Skunkton.  For  the  first  time  it  struck  me 
that  the  sender  might  have  been  a  trifle 


Half  a 
Jimmy 


.  Jimmy  Did  His  'Ether  Blasting'  With  a  Full,  Round  Kilowatt,  and  a  Kilowatt  At 
Mile  Gives  Forth  an  Easily  Readable  Signal,  Brother!    It  Is  In  Fact,  Quite  Audible. 
Told  Me  That  He  Had  Just  Received  a  Relay  Message  From  Ashheap,  Ohio,  and 
Would  I  Deliver  it?    Would  I?    Well  " 


more  explicit.  A  gentle  hint,  you  know,  as 
to  what  end  of  the  city  we  might  reason- 
ably hope  to  locate  H.  in,  at  least. 

I  stopt  and  leaned  against  a  wall.  This 
problem  merited  consideration.  I  was  sure 
up  against  it.  Vainly  I  sought  for  a  logical 
starting  point.  Here  was  a  situation  that 
called  for  a  Sherlock  Holmes. 

Thinking  of  Sherlock  Holmes  brought  a 
ghost  of  an  idea — a  mere  wraith  of  one. 
Deduction— that's  what  this  called  for. 
Very  well,  I'd  deduce. 

Deducing  at  midnight  in  a  temperature  of 
only  a  few  scrawny  degrees  above  zero  is 
rather  more  difficult  than  the  uninitiated 
might  imagine.  Eventually  I  got  the  case 
boiled  down  to  the  following  elements. 
Here  was  a  telegram  from  Maria  Peck  to 
H.  Peck.  Both  surnames  the  same.  Evi- 
dently related.  Sister  or  wife,  no  doubt.  I 
eliminated  the  former  as  being  unlikely  and 
arrived  at  the  conclusion  that  Maria  and 
H.  were  joined  in  matrimony.  Then,  too, 
there  was  the  fact  that  Maria  was  in  Ash- 


heap while  H.  was,  supposedly  at  least,  in 
Skunkton. 

Now,  when  a  man's  wife  is  away  does 
he  hang  around  home?  He  does  not. 
Where —  It  was  then  that  I  got  my 
brilliant  idea.  I  headed  straight  for  the 
nearest  saloon.  Sticking  my  head  in  the 
door  I  called  in  loud  tones,  "Telegram  for 
H.  Peck." 

And  without  a  second's  hesitation  four 
gentlemen  stept  toward  me  with  out- 
stretched hands. 

When    I    had    sufficiently    recovered  I 
looked  over  the  four  that  stood  before  me. 
"Good  Lord,"  I  gasped,  "It  can't  be  for 
all  of  you.    What  are  your  first  names?" 
And  in   rotation   I  got  the  following: 
Henry,  Horace,  Ho- 
ratio, and  Hannibal. 
And  the  worst  of  it 
was  that  any  one  of 
them  might  be  the 
sendee. 

Once  again  inspi- 
ration came  to  my 
assistance.  "Do  any 
of  you  belong  to  a 
wife  named  Maria?" 
I  demanded.  The 
quartette  pleaded 
"Not  guilty"  in  a 
breath,  and  I  stept 
outside  to  do  a  lit- 
tle more  deducing. 

Under  the  awning, 
partially  sheltered 
from  the  blinding 
snow,  I  made  futile 
attempts  to  warm 
my  ears,  and  gave 
the  Sherlock  Holmes 
stuff  another  hitch. 
Ah,  I  had  it!  The 
city  directory. 

Ten  minutes  later 
I  handed  the  direc- 
tory back  to  the 
bored  drug  -  clerk, 
and  gazed  about  me 
helplessly.  The  city 
directory  was  evi- 
dently a  very  com- 
plete work  and  must 
have  been  very  care- 
fully compiled.  Any- 
how, it  listed  just 
forty-seven  Pecks 
whose  first  name  be- 
gan with  an  H.,  any 
one  of  which  might 


be  my  quarry,  and  four  of  which  were  cer- 
tainly not.  For  Horatio,  Henry,  Horace, 
and  Hannibal  were  duly  accounted  for. 

It  looked  like  a  war  of  elimination.  I 
aroused  the  drug  clerk  from  his  trance 
and  asked  his  advice.  After  some  thought, 
he  advised  one  .  of  two  things :  use  the 
telephone  on  such  of  the  Pecks  as  pos- 
sest  the  accessory,  or  go  home  and  go  to 
bed,  preferably  the  latter. 

At  exactly  one  A.  M.  I  stood  once  more 
on  the  exterior  of  the  drug  store.  Out 
of  the  forty-three  Pecks  remaining  after 
barring  Horace  Horatio,  Henry,  and  Hanni- 
bal, I  had  succeeded  in  reaching  forty,  all 
in  various  stages  of  irritation,  the  last  be- 
ing the  worst,  as  he  had  been  called  from 
the  warmest  bed. 

But  I  hadn't  been  able  to  hang  the  ac- 
cursed dispatch  onto  any  of  the  forty  to 
which  I  was  playing  Ali  Baba.  There  re- 
mained three  H.  Pecks — one  on  Chestnut 
St.,  1024  East;  one  on  Center  Ave.,  No.  4 
West ;  and  one  on  Brown  St.,  413  North.  To 


January,  1918 


ELECTRICAL  EXPERIMENTER 


those  of  you  who  are  familiar  with  the 
topography,  of  Skunkton  the  difficulty  will 
be  apparent  on  a  little  thought.  For  the 
benefit  of  those  who  have  never  been  in 
our  burg  let  me  say  that  Chestnut  Street  is 
one  mile  from  the  spot  on  which  I  stood, 
the  Brown  Street  address  about  a  half  a 
mile  from  that,  and  No.  4  Center  Avenue 
approximately  one  mile  and  a  half  from 
the  Brown  Street  outfit.  About  three  miles 
of  real  icy  going  in  the  face  of  a  snow 
storm,  and  a  temperature  of  about  ten  de- 
grees above. 

I  selected  my  first  try  by  the  simple 
but  effective  "counting  out"  of  boyhood 
days.  "Eeny,  meeny,  etc."  And  the  lot 
fell  on  the  Chestnut  Street  entry. 

Having  thus  decided,  I  drew  my  over- 
coat more  closely  about  me,  and  started. 

1024  Chestnut  Street  was  discouragingly 
dark.  Long  and  continuous  ringing,  how- 
ever, eventually  brought  this  particular  be- 
slippered  and  bathrobed  Peck  to  his  very 
cold  front  door.  There  was  about  six  feet 
of  him,  every  millimeter  of  it  very  cold 
and  very  angry.    "Well,"  he  demanded. 

"Is  your  wife  in  Ashheap,  Ohio?"  I  in- 
quired, politely. 

"Well,  you  three-plyed,  hog  branded, 
triple  expanding  fool !  Have  you  gotten 
me  out  of  my  warm  bed  at  this  hour  to 
ask  me  that?    Well — " 

"I  have  a  telegram  from  her  to  you,"  I 
said,  hurriedly,  trying  to  stem  the  rising 
flood. 

"You  have  like — cinnamon !"  he  roared. 
"It  was  my  wife  that  woke  me  up  and  told 
me  there  was  an  idiot  ringing  our  door 
bell." 

I  stood  staring  blankly  at  the  closed 
door — which  had  closed,  by  the  way,  with 
quite  some  momentum.  Anyway,  that 
eliminated  1024  Chestnut  Street.  I  wended 
my  way  doggedly  toward  Brown  Street. 

I  will  not  dwell  on  the  harrowing  de- 
tails of  the  interview  at  413  Brown.  I  will 
draw,  as  the  novelists  say,  a  merciful  veil. 
There  are  many  ladies  among  the  readers 
of  this  magazine,  and — oh,  well — .  Suffice 
it  to  say  that  the  H.  Peck  who  resided  at 
413  Brown  Street  was  NOT  the  H.  Peck 
I  was  looking  for.  And  he  told  me  so. 
Explicitly ! 

Persistence  will  win,  and  eventually  I 
stood  at  No.  4  Center  Avenue.  I  rang  the 
bell.  The  response  was  gratefully  and  as- 
toundingly  rapid.  Before  the  sound  of  the 
bell  had  died  away,  a  window  on  the  sec- 
ond floor  flew  up,  and  a  scared  little  man 
in  a  night-cap  peered  down  at  me.  "What 
is  it?"  he  asked  in  trembling,  apprehensive 
tones.  "Are  you  H.  Peck?"  I  mumbled 
through  cold  stiffened  lips.  "Yes,  sir," 
came  the  quavered  affirmative.  "Is  your 
wife  in  Ashheap,  Ohio?"  "Yes,  sir,"  more 
quavery  and  much  more  apprehensively. 

"Thank  God,"  I  said  fervently.  The  little 
man  fairly  beamed.    "Yes,  sir,"  he  said. 

"Telegram  from  her  for  you — wireless 
message,  you  know,"  I  said.  The  scared 
look  returned  to  the  face  of  the  victim 
above.  "Be  right  down,"  he  said,  hur- 
riedly. 

Two  minutes  later,  after  a  preliminary 
rattle  of  drawn  bolts  and  dropt  chains, 
he  opened  the  door  and  scrutinized  me 
closely.  Standing  still  to  be  scrutinized  at 
the  existing  temperature  brought  my  al- 
ready badly  strained  temper  to  the  rupture 
point.  I  was  about  to  say  something,  cal- 
culated to  bring  action  of  some  sort  quick, 
when  the  little  guy  spoke.  "So  you  are  a 
telegraph  man,"  he  said. 

"Telegraph  man  is  right,"  I  retorted. 
"Substituting  for  Dr.  Cook.  If  you're  a  hu- 
man being  ask  me  to  come  in." 

"Certainly!  Certainly!  Come  in,  it's 
cold."  Which  was  the  first  sane  remark 
I'd  heard  for  hours. 


Once  in  the  scrupulously  clean  parlor  into 
which  he  led  the  way,  I  handed  over  the 
white  elephant  of  a  message  with  a  sigh 
of  relief,  and  took  a  slant  at  my  host  as 
he  read. 

He  was  a  little  man,  with  a  head  as  bald 
as  a  billiard  ball  and  scrubby  side-boards. 
Hen-pecked  was  written  on  his  countenance 
as  plainly  as  tho  it  had  actually  been 
branded  on  his  hide.  You  know,  the  type 
cartoonists  use  as  models.  As  he  read  the 
message  from  his  better  three-quarters,  he 
paled  visibly,  and  for  a  long  time  he 
continued  to  study  it  with  perturbed 
countenance  while  I  sat  patiently  twirling 
my  accursed  derby. 

Finally    he    lowered    the    message  and 

The  February  "E.E." 

§H  The  February  issue  of  the  Elec-  J 
B.  trical  Experimenter  will  contain  B. 
ij  over  one  hundred  articles  treating  on  B 
j§  Electrical,    Mechanical    and  Radio 

\  matters  of  supreme  interest  to  our  B 
HI  readers,  both  young  and  old.  The  H. 
E  Wireless  Department  will  contain  E 
B.  several  timely  and  important  articles,  B 
§B  and  all  those  interested  in  this  sub-  B 
H  feet  should  not  miss  them.  There  jj 
jj  will  also  be  a  number  of  highly  inter-  = 
H  esting  scientific  articles,  as  well  as  the  B 
B  usual  complement  of  "How-to-Make-  § 
j|  It"  and  Constructional  articles.  And  E 
B  while  we  are  on  the  subject,  readers,  S 
B  do  not  forget  to  read  the  "re-mailing  E 
H  notice"  on  the  front  cover,  whereby  S 
E  you  can  help  to  provide  good  reading  B 
jj  for  our  brave  soldiers  at  the  small 

|  cost  of  I  cent. 

,  "Hozv  Jimmy  Saved  the  Troop  B 
H  Train" — a  real  live  electrical  tale,  E 
=  mixed  with  patriotism,  that  zvill  hold  E 
B  you  spell-bound — by  John  T.  Dwyer.  B 
B  Baron  Miinchhausen's  New  Scien-  E 
B  tific  Adventures,  by  Hugo  Gernsback.  B 
IB  New  Substitute  for  the  Selenium  S 
B_  Cell — A  remarkable  Light-Sensitive  E 
B  Electrical  Device.  g 
g  How  One  Patriotic  American  Con-  B 
B  cern  Is  Teaching  the  Blind  to  Make  = 
B  Electrical  Apparatus.  g 
HI  "New  Radio  Wrinkles,"  by  H.  Win-  = 
B  field  Secor.  g 
B  "Experimental  Mechanics,"  Lesson  B 
jj  II — describing  the  "Lathe,"  by  Samuel  E 
jj  Cohen.  E 
B  "High  Frequency  Phenomena  and  B 
jj  Experiments,"  by  Frederick  Von  B 
B  Lichtenow.  B 
E  "The  Home  Treatment  of  Tuber-  g 
H  culosis  by  High  Frequency  Currents,"  B 
E  by  Dr.  Frederick  Finch  Strong.  jj 
E  "The  How  and  Why  of  Radio  B 
3  Apparatus" — describing  Tuning  Coils,  jj 
H  Loose  Couplers,  Variometers,  Etc.,  g 
jj  Part  VI.  .  j§ 

jj  "A  Wonderful  New  Electro-Musi-  B 
B  cal  Orchestra"  by  H.  Hartman,  C.  E.  B 

taiiiiiiB 

looked  at  me.  "Excuse  me  for  a  moment," 
he  said,  hurriedly.  "I  must  attend  to  some- 
thing at  once."  And  without  waiting  for 
a  reply  he  left  the  room. 

I  waited  patiently.  In  about  ten  minutes 
Mr.  Peck  reappeared.  He  was  apparently 
very  much  perturbed.  He  looked  at  me 
thoughtfully  for  a  moment  before  he 
spoke.  "How  much  does  this  wireless  ser- 
vice cost  per  word?  I  would  like  to  send 
a  reply  to  my  wife."  I  assured  him  that 
there  was  no  cost  attached,  that  by  these 
little  services  we  amateurs  justified  our 
existence.  "And  how  many  words  am  I 
limited  to?"  he  inquired. 

"Go  as  far  as  you  like,"  I  invited,  care- 
lessly.   Then  with  more  caution,  "That  is, 


within  reason,  of  course.  I  don't  know 
that  I'd  care  to  transmit  the  story  of  your 
life,  or  anything  like  that.  Be  as  brief  as 
possible  and  be  explicit.  Use  your  judg- 
ment." I  pulled  a  couple  of  forms  from 
my  pocket  and  handed  them  to  him.  "Go 
get  'em." 

Mr.  Peck  trotted  obediently  from  the 
room.  I  reckon  obedience  was  a  habit  with 
him.  Judging  from  appearances,  marriage 
had  been  more  of  an  enlistment  to  the  poor 
little  animal  than  anything  else,  and  he 
looked  and  acted  as  if  he  had  had  lots  of 
what  the  U.  S.  Army  officers  call  good, 
healthy  discipline. 

After  some  little  wait  Peck  came  into 
the  room  and  handed  me  a  folded  blank. 
He  was  profuse  in  his  thanks.  Assuring 
him  that  a  world  of  thanks  and  a  mint 
of  money  could  never  repay  me  for  what 
I'd  been  thru  that  night,  I  made  my  get- 
away. 

The  return  trip  was  practically  without 
incident.  It  was  so  cold  that  the  police- 
men could  not  sleep,  and  I  encountered 
two  or  three  of  these  restless  knights  who 
seemed  to  possess  inherently  suspicious  dis- 
positions. I  satisfied  these  minions  of  the 
law  that  I  was  what  I  didn't  seem,  i.  e.,  a 
peaceful  and  law-abiding  citizen,  and 
eventually  arrived  at  my  home.  As  I 
mounted  the  steps  I  reflected  on  my  inno- 
cence of  a  few  hours  before.  Adam  must 
have  had  much  the  same  thoughts  after  he 
had  gotten  outside  of  the  historic  apple. 

I  entered  my  apparatus  room,  threw  off 
my  coat,  hat  and  muffler  and  lit  the  gas. 
Then  I  sat  down  to  wait  until  my  fingers 
had  thawed  out  sufficiently  to  give  a  fairly 
decent  imitation  of  continental. 

It  was  four-thirty.  I  had  quite  a  few 
doubts  as  to  whether  Jim  was  still  hold- 
ing the  fort  at  the  other  end.  So  as  soon 
as  I  possibly  could  I  sat  down  to  the  table 
with  H.  Peck's  reply  unopened  in  my  hand. 
Throwing  down  the  antenna  switch,  I 
jerked  forth  three  rather  unsteady  3 
F.  U.  L.'s.  Then  I  listened.  Right  back 
at  me  came  faithful  old  Jim's  — .  — .  When 
it  came  to  sticking  to  his  post,  Jim  had 
out-Binnsed  Binns ! 

Down  went  my  antenna  switch,  and  I 
tore  off  the  preliminary  call  while  open- 
ing H.'s  little  composition  with  my  left 
hand.  Then  I  paused,  as  the  full  force  of 
the  tragedy  bore  home  on  me.  Henry  had 
obeyed  instructions  like  a  soldier.  He  had 
been  both  brief  and  explicit.  He  had 
evolved  a  regular  one  of  those  "we  have 
met  the  enemy  and  he  is  ours"  things. 
It  follows : 

To  Mrs.  Maria  Peck, 

Ashheap,  Ohio. 
I  had  already  lit  the  fire.  Billy 
was  in  the  oven.    I  am  burying 
him  in  the  garden. 

Henry  Peck. 
My  spark  buzzed  and  jumped  as  I  sen 
this  brief  account  of  the  tragedy  winging 
along  on  the  first  leg  at  twenty  per.  For 
tragedy  it  was  doubtless  fated  to  be  for 
Henry  Peck  when  the  common  carriers 
succeeded  in  filling  their  contract  with 
Mrs.  Peck  and  dropt  her  on  the  station 
platform  at  Skunkton.  And  I  strongly 
doubt  if  Billy  enjoyed  the  performance  any 
too  well. 

In  conclusion  I've  got  just  this  to  say. 
If  that  feline  Billy  had,  during  his  career- 
on  this  vale  of  tears,  strayed  from  the 
paths  of  righteousness,  I'll  bet  a  5  K.  W. 
transforming  tool  against  a  piece  of  un- 
improved real  estate  two  inches  by  four 
that  he  tobogganed  into  the  Sweet  Bye 
and  Bye  without  the  least  fear  of  what 
was  to  come.  At  a  Methodist  camp  meet- 
ing I  once  heard  a  select  quartet  sing,  "Oh 
what  a  foretaste  of  glory  divine."  Fore- 
taste ! !    Billy  got  a  mouthful ! 


612 


ELECTRICAL  EXPERIMENTER 


January,  1918 


Notice  to  All  Radio  Readers 

As  most  of  our  radio  readers  are  undoubtedly  aware,  the  U.  S.  Government  has  decided  that  all  Amateur  Wireless  Sta- 
tions, whether  licensed  or  unlicensed,  or  equipt  for  receiving  or  transmitting,  shall  be  closed. 

This  is  a  very  important  consideration,  especially  to  those  who  are  readers  of  THE  ELECTRICAL  EXPERIMENTER, 
for  the  reason  that  we  desire  to  continue  to  publish  valuable  articles  on  the  wireless  art  from  time  to  time,  and  which  may  treat 
on  both  transmitting  and  receiving  apparatus.  In  the  first  place,  there  are  a  great  many  students  among  our  readers  who  will 
demand  and  expect  a  continuation  of  the  usual  class  of  Radio  subjects,  which  we  have  publisht  in  the  past  four  years,  and 
secondly,  there  will  be  hundreds  and  even  thousands  of  new  radio  pupils  in  the  various  naval  and  civilian  schools  thruout 
the  country,  who  will  be  benefited  by  up-to-date  wireless  articles  treating  on  both  the  transmitting  as  well  as  receiving  equip- 
ment.   Remember  that  you  must  not  connect  up  radio  apparatus  to  any  form  of  antenna. — The  Editors. 


"Electrician— Radio  U.  S.  N." 

By  WILLARD  CONNELY,  Chief  Yeoman,  U.  S.  N.  R.  F. 


yet 
dis- 


IT  is  easy  to  understand  why  electricity 
is  one  of  the  two  or  three  most  pop- 
ular courses  of  training  chosen  by 
youths  who  enlist  in  the  Navy.  The 
intense  modernism  in  electricity, 
the  persistent  mystery  of  it,  its  new 
coveries  which  seem  unlimited,  and 
the  unusual  chances  it  offers  for 
frequent  promotion — all  these  forces 
are  so  many  magnets  to  the  blue- 
jacket who  feels  within  him  the  steel 
of  ambition. 

Since  America  surged  into  the  War 
hundreds  of  college  men  have  en- 
rolled in  the  ranks  of  the  naval  ap- 
prentices. So  have  hundreds  of  stu- 
dents who  quit  high  school  to  become 
sailors.  Still,  with  the  personnel  of 
the  Navy  numbered  in  hundreds  of 
thousands  it  is  not  surprising  that  a 
majority  of  the  enlisted  men  have  not 
completed  high  school  education. 
Uncle  Sam,  however,  treats  them  all 
impartially.  Unlike  a  college,  he  is 
not  so  particular  whether  or  not  an 
electrical  aspirant  knows  Ohm's  law 
at  the  time  he  signs  up.  Soundness 
of  body  is  the  prime  requirement. 


If  a  man  has  learned  something  of 
physics  at  school,  often  he  is  fascinated  by 
his  experiments  in  static  electricity.  If  a 
man  has  left  school  to  work  in  an  electrical 
shop  and  learn  the  business,  often  he  is 
kept  at  primary  work,  such  as  armature 


tices, 


it,  to  learn  something  new  every  day,  to 
get  ahead  faster,  so  to  rely  upon  it  for  a 
life  competence.  But  they  lack  the  money. 
Right  there  is  where  the  Navy  comes  forth 
with  the  needed  boost — feeds  the  appren- 
furnishes  all  clothes  free,  teaches 
thoroly  the  trade,  and  good  pay  for 
every  man  starts  from  the  day  of  en- 
listment. With  this  splendid  liberal 
opening  which  invites  young  men  to 
serve  their  country  with  honor  as 
well  as  immeasurably  to  better  them- 
selves as  expert  craftsmen,  every 
amateur  electrical  enthusiast  in  the 
United  States  should  know  just  what 
can  be  had  for  the  enlisting.  Then 
will  he  meditate. 

Too  many  American  youths,  indeed 
thousands  of  them  wedded  to  elec- 
tricity, begin  at  the  bottom  and — stay 
there.  A  dozen  insurmountable  ob- 
stacles may  prevent  their  getting 
ahead.  Unlikely  surroundings  may 
stifle  initiative.  Irregular  habits  may 
impair  efficiency.  But  Uncle  Sam 
sees  that  his  bluejackets  go  forward. 
He  produces — make  no  mistake  about 
this — he  produces  electricians. 


Three  Interesting  Views  of  the  Radio  and  Electrical  Students  at  the  Unsaltiest  Naval  School  in  the  Country — Dunwoody  Naval  Training 
School,  Minneapolis,  Minn.     The  Future  "Blue-jackets"  Are  Given  a  Very  Thoro  Education  in  the  Theory  and  Practice  of  Electricity  and 

Mechanics.   Top  Photo  Shows  Class  in  Welding  and  Brazing. 


Development  of  the  mind  through  disci- 
plinary training  will  follow.  Uncle  Sam 
takes  a  chance  on  that,  and  he  seldom  loses 
eut. 


winding,  for  months  and  months  before  he 
is  allowed  to  get  a  broader  grasp  of  the 
craft.  Both  these  types  of  men  would  like 
to  know  more  about  electricity,  to  study 


One  of  the  purposes  of  this  article  is  to 
make  plain  the  circumstance  that  a  sailor 
is  not  always  detailed  to  the  coast  or  to 
{Continued  on  page  633) 


January,  1918 


ELECTRICAL  EXPERIMENTER 


613 


THE  "SMALLEST  AUDION" 

The  very  rapid  strides  in  the  making  of 
electronic  receiving  devices  has  rendered 
possible  the  production  of  some  very  small 
ones.  When  the  Audion  was  first  made,  its 
size  was  very  large  as  compared  with  the 
present  type,  but  as  developments  in  the  art 
changed  this,  it  was  found  that  the  smaller 
types  of  the  same  instrument  would  per- 
form the  same  functions  as  that  of  the  large 
size. 

We  show  herewith  two  types  of  electronic 
devices  which  have  been  made  especially  for 
certain  experimental  work  for  Mr.  Samuel 
Cohen,  a  Brooklyn,  N.  Y.,  radio  ex- 
perimenter. The  Fleming  valve  is  seen  at 
bottom  of  the  photograph,  and  it  consists 
of  the  standard  miniature  3>4  volt  filament 
lamp  and  the  evacuated  chamber  is  5/i»  of 
an  inch  in  diameter.  The  cold  electrode  is 
made  from  tungsten,  and  is  made  in  semi- 
circular form  in  order  to  receive  the 
maximum  electronic  discharge  from  the  hot 
cathode  or  filament.  The  connection  from 
this  cold  plate  is  obtained  by  the  means  of 
a  copper  wire  which  protrudes  from  the 
glass  chamber,  and  is  seen  to  the  left  of  the 
tube  in  the  photograph.  With  this  tube, 
favorable  results  have  been  obtained  from 
nearby  signals ;  the  standard  Fleming  valve 
circuit  was  employed. 

The  de  Forest  Audion  tube  is  illustrated 
at  the  top  of  the  illustration,  and  it  con- 
tains all  of  the  elements  which  are  in  the 
standard  tube,  namely — filament,  grid  and 
win'g.  The  vacuum  chamber  of  the  device 
in  which  the  various  elements  are  enclosed, 
measures  V/2  inches  by  inch  in  diameter 
over  all.  The  seal-off  is  made  at  the  end 
of  the  bulb  as  indicated. 

The  filament  consists  of  a  specially  made 
spiral  tungsten  filament  and  this  is  enclosed 
in  the  grid,  which  consists  of  another  spiral 
made  from  copper,  the  same  being  kept  in 
position  by  means  of  a  platinum  wire  which 
leads  from  the  lower  end  of  the  tube.  The 
wing  of  this  device  is  composed  of  a  very 
closely  meshed  tungsten  cylinder. 

Quite  remarkable  results  have  been 
obtained  from  this  instrument  in  conjunc- 
tion with  a  portable  radio  receiving  outfit. 
Long  distance  reception  has  been  obtained 
with  this  tube,  it  having  been  possible  to 
produce  undamped  oscillations  for  the 
reception  of  distant  stations  employing  the 
undamped  wave  generator.  The  tube  has 
also  been  utilized  with  great  success  in  the 
making  of  a  "fountain  pen"  radio  receiver, 
and  very  interesting  results  have  been 
obtained  therefrom. 


Radio  Men  Are  So  Accustomed  to 
Seeing  Large  Sized  "Audions," 
That  These  Tiny  Specimens  Might 
Appear  to  Be  Mere  Watch-fobs. 
But  Such  Is  Not  the  Case.  The 
Smaller  One,  at  the  Bottom  of  the 
Photo,  Has  Done  Very  Creditable 
Work  Indeed,  Even  Tho  It  Is  No 
Larger  Than  a  Flashlight  Bulb. 
The  Larger  Bulb  Contains  "Fila- 
ment, Grid  and  Wing." 


RADIO  CONTROLLED  MINES         various  conditions,  and  with  a  number  of 
A    California  genius,   Mr.   Hyder,   has     different  radio  plants  and  sending  stations* 
perfected  a  new  radio  controlled  mine  which     using  various  wave  lengths.    It  is  further 


Radio  Receiving  Apparatus,  Including  Selective  Relays,  Wave  Filters,  etc.,  Used  in  Call- 
fornlan's  New  Radio  Controlled  Mine.    It  Is  Claimed  to  Be  Non-lnterferable,  Enemy  Waves 

Having  No  Effect  at  All  Upon  It. 


can  be  detonated  at  will  by  sending  out  a 
prearranged  radio  signal  or  series  of  signals. 
The  photograph  herewith  shows  the  selec- 
tive mine  construction  invented  by  Mr.  Hy- 
der, which  cannot  possibly  be  interfered  with 
by  any  sending  device  other  than  the  control- 
ling machine,  so  the  inventor  claims.  This 
has   been   tried   and  tested  thoroly  under 


claimed  that  the  device  has  been  put  to 
almost  every  known  test  condition  by  the 
inventor,  and  so  far  no  person  has  been 
able  to  operate  the  apparatus  except  the 
inventor,  nor  has  any  one  been  able  to  in- 
terfere with  the  action  of  the  device.  Such 
a  device  should  prove  of  great  value. — 
Photo  from  G.  IV.  Geiger. 


MEASUREMENTS     OF  RADIO 
ANTENNA  ON  SHIPBOARD. 

In  the  October,  1917  issue  of  The  Elec- 
trical Experimenter,  on  page  391,  Mr.  F. 
A.  Hart  gives  a  table  of  constants  for 
radio  antenna.  This  table  is  of  practically 
no  value  unless  the  spacing  of  the  parallel 
wires  in  the  antenna  is  given,  says  Mr.  F. 
H.  Kroger,  Chief  Engineer,  National  Elec- 
tric Signaling  Co..  With  this  additional 
data  the  table  would,  indeed,  be  of  consider- 
able value. 

Mr.  Hart,  in  reply,  says :  I  do  not  agree 
with  Mr.  Kroger  that  the  data  previously 
given  are  valueless  without  the  spacing 
values,  as  practically  everyone  engaged  in 
radio  work  is  familiar  with  the  average 
spacing  between  wires.  However,  with  this 
additional  data  the  table  should  now  be  very 
complete.  (Every  radio  reader  should  pro- 
cure a  copy  of  the  table  previously  pub- 
lisht  in  The  Electrical  Experimenter, 
as  it  contains  data  obtained  from  actual 
tests.) 

Spacing  between  Wires. 

Horizontal  Horizontal. 
No.    2-Wire      Ft.  in.         No.    6-lVire      Ft.  in. 

1   12    0  23   2  3 

2   10    0  24   2  3 

3   12    6  25   2  3 

4   10    0  26   2  3 

5   12    0         27   2  3 

6   10    0         28   2  3 

7  ....    13    0         29   2  3 

4-wire  30   2  3 

8   3    4         31   2  3 

9   3    4         32   2  3 

10   3    4  33  

11   3    4         34   2  0 

12   3    4         35  •   2  3 

13   3    4         36   2  3 

14   3    0         37   2  3 

15   3    4         38   2  3 

16   3    4  39   2  3 

17   3  4 

18   3    4  10-  Wire 

19   3  0 

20   3    0         40   1  4 

21   3  6 

22   3  4 


In  33  spacing  forward  is  2  ft.  3  in.,  80 
ft.  in  to  centre  spacing  between  three  wires 
(set  each  side)  12  in.,  spacing  between  two 
inside  wires  at  centre  19  ft.  Aft  end  85  ft. 
from  centre  spacing  graduates  to  2  ft.  3  in. 

Vertical  lengths  are  identical  with  hori- 
zontal at  junction  of  wires  graduating  to  a 
point  approximately  2  ft.  at  bottom. 


MOUNTING   TINFOIL    ON  GLASS 
CONDENSER  PLATES. 

A  good  shellac  for  fastening  the  foil  to 
the  glass  in  transmitting  condensers  may  be 
made  by  dissolving  as  much  powdered  rosin 
as  possible  in  one  ounce  of  turpentine  and 
thinning  the  mixture  by  the  addition  of  one- 
half  ounce  of  alcohol.  Only  a  very  small 
amount  of  rosin  will  be  needed. 

About  three  drops  of  shellac  should  be 
put  in  the  center  of  the  surface  of  the  glass 
and  rubbed  around  well.  Place  the  foil  on 
the  glass  and  roll  it  fast  with  a  photo- 
graphic print  roller.  The  foil  must  be  placed 
on  at  once,  as  the  mixture  dries  quickly. 
When  this  varnish  is  used  the  plates  may 
either  be  stacked  or  placed  in  an  open  rack. 


=    RADIO  WRITERS 


ATTENTION  I  !  I 


Can  you  write  radio  articles  dealing 
with  the  practical  problems  of  wireless 
operating?  We  can  use  some  good 
papers  on  such  subjects  as  "the  tuning 
of  radio  transmitters";  "the  use  of  the 
wave  meter,  including  its  application 
to  measuring  the  frequency,  wave 
length  and  decrement";  "operation  of 
commercial  transmitting  and  receiving 
sets";  "the  operation  of  army  trunk 
sets";  "improved  ways  of  receiving 
undamped  wave  signals,"  also  new 
ideas  and  short-cuts  for  learning  the 
codes.  We  pay  well  for  all  articles 
accepted.  Help  yourself,  your  maga- 
zine and  your  country. 


614 


ELECTRICAL  EXPERIMENTER 


January,  1918 


French  Aeroplane  Radio  Great  Aid  to  Artillery 


ALTHO  wireless  experiments  in  con- 
/\    nection  with  aeroplanes  were  made 
y   \  in  1910,  it  was  not  until  the  begin- 
**-  -*-ning  of  the  war  that  it  was  put  into 
actual  use.    All  aeroplanes  used  for 
the  directing  of  artillery  are  now  equipt 
with  wireless  outfits  which  are  powerful 
enough  to  transmit  a  distance  of  ninety 
miles  if  necessary.    They  can  both  trans- 
mit and  receive,  the  sounds  being  perceptible 
in  spite  of  the  humming  of  the  motor. 

The  electrical  energy  for  the  transmitter 
is  supplied  by  a  small  dynamo  which  re- 
ceives its  power  from  a  screw  placed  in 
front  of  the  machine  and  actuated  by  the 
motion  of  the  air.  The  aeroplanes  keep  in 
touch  with  their  batteries  at 
all  times.  It  is  the  observer 
in  the  aeroplane  who  con- 
trols the  gun  fire.  He  sights 
the  objects,  gives  the  signal 
and  reports  where  the  shell 
has  fallen.  The  top  photo 
shows  a  French  aeroplane 
fitted  with  wireless.  The 
small  propeller  on  the  right 
drives  the  dynamo.  The 
bottom  photo  shows  the 
wheel  or  drum  upon  which 
the  antenna  is  coiled ;  also 
the  wireless  telegraph  set 
mounted  inside  the  aero- 
plane cab. 


the  battery  was  never  reliable  to  any  degree. 

The  rotting  of  the  positive  plate  is  due 
to  electric  conduction  across  the  lid  of  the 
cell  when  wet  with  sulfuric  acid.  In  the 
case  of  the  wood  and  indiarubber  covers 
which  fit  tightly  round  the  lead,  the  action 
goes  on  more  rapidly  than  when  the  rods 
from  both  plates  pass  loosely  thru  glass 
tubes.  The  rotting  may  be  prevented  al- 
together by  doing  away  with  the  cover,  but 
some  other  device  is  needed  to  keep  the 
plates  in  position  and  prevent  the  splashing 
of  the  acid  when  the  cell  is  being  charged. 
It  would  be  convenient  to  have  the  glass 
cells  made  with  ridges  to  keep  the  plates 
vertical,  but  such  cells  cannot  be  obtained 


HIGH-POTENTIAL 
BATTERIES  FOR 
AUDIONS 
By  Frank  Horton,  SC.D. 

The  difficulties  attending 
the  use  of  a  high-potential 
battery  capable  of  supplying 
a  current  of  a  few  milli- 
amperes  are  familiar  to  all 
who  have  experimented  with 
the  discharge  of  electricity 
thru  gases.  The  type  of  bat- 
tery very  often  employed 
for  this  purpose  consists  of 
a  number  of  small  secondary 
cells  with  lead  plates.  The 
chief  trouble  is  the  "rotting" 
of  the  lead  of  the  positive 
plate  at  the  point  where  it 
passes  thru  the  cover  of  the 
cell,  says  Dr.  Frank  Horton 
in  the  Philosophical  Maga- 
zine. The  rotting  consist^ 
in  the  formation  of  a  white 
powder  which  analysis 
shows  to  consist  mainly  of 
lead  sulfate;  in  a  few 
months,  or  even  weeks,  the 
rod  may  thus  be  separated 
into  two  pieces.  The  rapidity 
of  this  action  depends  on 
the  quality  of  the  lead  used. 

This  type  of  small  storage-cell  was 
originally  provided  with  an  indiarubber 
cover,  but  the  contact  of  the  rubber  and  the 
lead  was  found  to  be  the  cause  of  rotting 
which  occurs.  The  lead  rods  of  the  elec- 
trodes were  therefore  covered  with  short 
glass  tubes  to  prevent  this  contact ;  this 
device  generally  lengthens  considerably  the 
life  of  the  cell.  More  recently  wooden  tops 
well  soaked  with  paraffin-wax  have  been 
substituted  for  the  rubber  and  glass  tubes ; 
but  these  appear  to  be  quite  as  bad  as  the 
old  indiarubber  ones.  About  20  per  cent, 
of  the  positives  of  a  new  battery  of  320 
such  cells  recently  rotted  thru  in  the  course 
of  three  months.  The  remaining  positives, 
and  the  new  ones  replacing  those  spoilt  were 
therefore  covered  with  glass  tubes  where 
they  pass  thru  the  wooden  covers ;  but  tho 
as  usual,  this  increased  the  length  of  service 
of  the  plates,  after  a  few  months  broken 
positives  were  continually  being  found  and 


This  Photograph  Shows  Clearly  How  a  French  Aeroplane  Is  Equipt  with 
Radio.    The  Transmitter  Is  Supplied  with  Current  From  a  Small  Dynamo 
Driven  By  the  Small  Air  Propeller  Marked  By  the  Arrow  In  Top  Photo 
Lower  Photo  Shows  Transmitting  Key  and  Instruments. 


potential  only  (or  only  a  very  minute  cur- 
rent) is  required.  They  are  often  trouble- 
some to  fit  up,  but  require  no  further  atten- 
tion if  treated  carefully.  For  currents  of 
the  order  of  0.01  ampere  dry  cells  may  be 
used,  and  the  writer  has  found  these  very 
convenient  for  this  purpose.  These  cells 
have  the  advantage  of  being  small,  thus 
enabling  a  large  number  to  be  packed  into 
a  small  space,  and  their  E.M.F.  falls  but 
slowly  when  current  of  only  a  few  milli- 
amperes  are  taken  from  the  battery. 

One  such  battery  is  for  supplying  poten- 
tials up  to  about  200  volts.  The  cells  are 
contained  in  a  wooden  box  61  cm.  long, 
18.5  cm.  wide  and  11.5  cm.  high.  This  has 
a  hard  rubber  plate  on  the  top  which  in- 
sulates the  plug-keys  by  means  of  which 
the  cells  are  arranged  in  series.  The  cells 
Tused  give  about  4  volts.  It 
is  advisable  not  to  have  too 
many  cells  connected  in 
series  when  the  battery  is 
not  in  use,  and  the  box 
therefore  contains  three  sets 
of  10  small  batteries  (each 
set  giving  about  40  volts), 
and  five  sets  of  five  small 
batteries  (each  set  giving 
about  20  volts).  The  sets 
are  insulated  by  micanite, 
and  they  can  all  be  con- 
nected in  series  by  means 
of  the  plug-keys.  The  re- 
quired potential  is  tapt  off 
by  inserting  special  plugs 
into  holes  in  the  insulated 
brass  pieces  connected  to  the 
I  cells. 

|  In  the  other  arrangement 
of  cells  which  has  been 
found  useful  the  box  con- 
tains 25  separate  dry  cells 
and  gives  a  total  E.M.F.  of 
about  35  volts.  The  cells 
are  connected  in  series  in- 
side the  box  and  by  turning 
a  handle  in  the  centre,  the 
difference  of  potential  be- 
tween the  two  terminals  can 
be  increased  by  aproximately 
equal  steps  from  0  to  35 
volts.  A  convenient  feature 
of  the  battery-box  is  the 
ease  with  which  the  cells 
can  be  removed  and  replaced 
by  new  ones.  The  cells  are 
cylindrical  in  shape,  the  out- 
side being  of  zinc  which  is 

ithe  negative  pole  of  the  cell. 
A  small  brass  cap  connected 
to  the  positive  pole  protrudes 

i'from  the  centre  of  the  top 
}f  the  cell.    The  cells  are 
.-each  about  5  cm.  high  and 
11.4  cm.  in  diameter.  They 


Photo  Central  News  Photo  Service 


at  the  present  time.  In  a  long  row  of  cells 
in  series  the  connecting  wires  can  be  made 
to  keep  the  plates  in  position,  but  a  safer 
device  is  to  cut  a  strip  of  thin  celluloid  of 
width  equal  to  the  distance  apart  of  the 
plates  and  to  bend  this  into  a  n  and  place 
it  between  the  plates  of  the  cell.  The  top 
of  the  celluloid  separator  should  be  below 
the  level  of  the  acid  in  the  cell  and  a  small 
hole  should  be  made  in  the  top  of  it  to  al- 
low the  gases  to  escape  when  the  cell  is 
being  charged.  The  splashing  of  the  acid 
can  be  prevented  in  the  usual  way  by  cover- 
ing the  surface  with  a  thin  layer  of  oil.  A 
battery  of  secondary  cells  arranged  in  this 
way  has  been  working  satisfactorily  for 
several  months. 

The  advantage  of  a  battery  which  does 
not  require  periodical  charging  is  obvious. 
Several  types  of  primary  cell  have  been 
used  and  are  usually  satisfactory  for  elec- 
trometer work  and  for  experiments  where 


lire  arranged  in  a  circle  be- 
Jftween  two  sheets  of  hard 
rubber,  one  of  which  forms 
the  top  of  thi;  box  and  the  other  is  inside 
the  box  and  is  supported  from  the  top  by 
four  hard  rubber  rods.  Each  cell  is  held 
in  position  by  two  copper  springs. 

Inside  the  box  a  radial  arm  makes  a  rub- 
bing contact  with  the  brass  clips  pressing 
on  the  central  projecting  positive  poles,  and 
the  position  of  the  arm  is  indicated  by  the 
pointer  which  moves  over  the  dial  on  the 
top  of  the  box.  This  arm  is  connected  to  a 
left-hand  terminal ;  the  other  terminal  is 
connected  to  the  zinc  of  the  first  cell  in  the 
series.  It  has  been  found  convenient  in 
practise  to  have  one  position  of  the  pointer 
in  which  there  is  no  connection  between 
the  terminals  ("off").  This  forms  a  simple 
method  of  breaking  the  battery  circuit.  It 
is  also  convenient  for  some  purposes  to 
have  a  position  in  which  the  terminals  are 
connected,  but  with  no  difference  of  poten- 
tial between  them  ("0").  The  next  position 
(Continued  on  page  652) 


January,  1918 


ELECTRICAL  EXPERIMENTER 


615 


A  Short-Gut  to  Code-Learning 

By  THOMAS  REED 


The  main  difficulty  in  learning  the  tele- 
graph or  radio  code,  lies  in  the  fact  that  the 
code-signs  (composed  of  dots  and  dashes) 
cannot  be  exprest  in  spoken  words.  They 
are  symbols  to  the  eye  only,  and  the  mind 
cannot  talk  to  itself  about  them,  lacking 
names  to  call  them. 

One  can,  of  course,  translate  them  into 
sounds  by  using  the  words  "dot"  and 
"dash" ;  but  the  repetition  of  these  words, 
in  varying  order  for  the  different  letters, 
soon  destroys  their  distinctiveness.  To 
illustrate,  imagine  the  difficulty  of  recalling 
the  names  of  six  men  called  respectively 
"James  Henry  Albert,"  "Albert  Henry 
James,"  Henry  Albert  James,"  "James  Al- 
bert Henry,"  "Albert  James  Henry,"  and 
"Henry  James  Albert." 

The  idea  is  already  in  use,  I  believe,  of 
representing  the  dots  and  dashes  by  alpha- 
betical letters,  using  capitals  for  the  dashes 
and  small  letters  for  the  dots,  thus :  F  = 
f f Ff ;  G  =  GGg,  etc.  This  helps  recogni- 
tion by  the  eye,  but  still  does  nothing 
toward  converting  the  signals  into  spoken 
words  which  one  can  repeat  to  himself  and 
memorize. 

Furthermore,  the  sounds  made  by  the  ac- 
tual telegraph  instruments  themselves  bear 
no  resemblance  to  the  appearance  of  the  dots 
and  dashes,  the  spoken  words  "dot"  and 
"dash,"  or  the  sound  of  the  alphabetical 
letter.  Leaving  out  the  "sounder"  of  land- 
lines,  and  confining  ourselves  to  "radio" 
signals,  we  find  that  they  are  heard  in  the 
form  of  long  and  short  buzzes;  and  the 
mind  is  required  by  a  dead-lift  effort  to 
associate  these  buzzes  with  the  dot-and- 
dash  symbols  and  the  corresponding  alpha- 
betic letters. 

But,  as  heard  in  the  radio  receiver,  each 
signal  has  a  distinctive  cadence  of  its  own, 
which  is  instantly  recognizable  as  a  whole 
and  not  as  a  series  of  dots  and  dashes ; 
just  as  a  word  is  recognized  as  such  and 
not  as  a  series  of  syllables.  In  fact,  the 
signal  sounds  almost  like  a  little  word  or 
phrase,  pronounced  in  a  lisping  language. 
Take  the  letter  "Y,"  for  example ;  the  re- 
ceiver says,  "Siss-a-siss-siss" ;  and  all  of  us, 
after  gaining  familiarity  with  it,  cease  to 
call  it  "dash-dot-dash-dash,"  but  express 
it  to  ourselves  as  "tah-de-dah-dah."  using 
the  phonetic  equivalent  imitating  the  cad- 
ence we  actually 
hear,  if  not  the 
sound  itself. 

Reasoning  from 
this  unconscious 
habit,  I  have 
thought  it  would 
assist  in  learning 
the  code  if  we 
could  select  for 
each  letter-signal 
a  certain  word 
(disregarding  its 
sense)  resembling 
the  sound  of  the 
signal  in  the  num- 
ber of  its  syllables 
and  in  its  accent. 
Such  words  could 
be  more  easily 
memorized  than 
could  arbitrary 
arrangements  o  f 
marks ;  and  each 
word  would  carry 
in  itself  not  only 
the  audible  sound 
of  the  signal  in  the 
receiving  instru- 
ment, but  an  index 
of  dots  and  dashes 
composing  it. 

I  have  selected  a 


list  of  phonetic  catch-words  which  can  be 
used  in  this  way.  The  initial  letter  of 
each  one  corresponds  to  the  alphabetic  let- 
ter which  it  represents.  The  accented 
syllables  (usually  with  long  vowels)  cor- 
respond to  the  dashes,  while  the  un- 
accented syllables  (usually  with  short 
vowels)  correspond  to  the  dots.  To  assist 
still  further,  the  dash-syllables  are  printed 
in  capitals  and  the  dot-syllables  in  small 
letters,  the  syllables  being  separated  by 
hyphens  for  greater  clearness. 

The  student,  having  memorized  the  list 
of  words,  is  now  provided  with  a  reference- 
index  in  his  head.  He  is  not  obliged  to 
remember  the  arbitrary  fact  that  "L,"  for 
instance,  is  "Dot-dash-dot-dot."  The  word 
"la-Bor-ri-ous"  occurs  to  him  because  it 
begins  with  "L,"  the  letter  wanted ;  and,  on 
analyzing  it,  the  long,  accented  syllable  in- 
dicates a  dash(  and  the  shorter  ones  dots, 
correctly  placed.  But  even  without  analyz- 
ing it,  the  sound  of  the  word  itself  gives 
him  the  clue  to  the  signal. 

The  pronunciation  of  the  catchword  also 
gives  the  correct  spacing  between  the  dots 
and  dashes,  a  thing  sometimes  quite  hard 
for  a  beginner  to  comprehend. 

Further,  in  receiving,  the  broken  buzzes 
of  the  signal  "L"  form  a  sound  resembling 
the  word  "Laborious,"  and  by  associating 
the  two  he  will  learn  more  quickly  to  recog- 
nize the  signal  as  a  whole,  instead  of  first 
having  to  resolve  it  into  its  component  dots 
and  dashes. 

Following  is  the  list  of  phonetic  catch- 
words. They  are  the  best  I  have  been  able 
to  find  in  the  limited  time  I  have  been  able 
to  give  to  the  matter,  and  for  some  of  the 
more  difficult  letters  I  have  had  to  use 
short  phrases  instead  of  single  words. 
However,  among  the  great  mass  of  words 
in  our  language,  a  set  should  be  found  accu- 
rately fitting  the  requirements.  Only  famil- 
iar words  should  be  used,  and  such  as  are 
not  variable  in  pronunciation.  The  Elec- 
trical Experimenter  might  open  a  compe- 
tition in  such  lists,  with  the  idea  of  com- 
bining the  best  words  into  a  perfect  set, 
which  could  thereafter  be  used  as  a  stand- 
ard. [We  shall  be  pleased  to  hear  from  any 
of  oar  readers  on  this  subject. — Editor.] 


Alphabetic 

Tel.  Code 

Graphic 

Phonetic 

Letter 

Sign 

Sign 

Catchword 

A 

aA 

a-WAY 

B 

Bbbb 

BLUE-ber-ry-ing 

C 

CcCc 

CO-ca-CO-la 

D 

Ddd 

DRA-per-y 

E 

etch 

F 

ffFf 

fil-i-PI-no 

G 

GGg 

GAL-VAN-ic 

H 

hhhh 

hel-ter-skel-ter 

I 

ii 

in-ner 

J 

jJJJ 

ja-PAN-NOW-OWNS 

K 

KkK 

KAL-so-MINE 

L 

1LU 

la-BO-ri-ous 

M 

MM 

MA-LAY 

N 

Nn 

NA-vy 

O 

ooo 

O-HI-O 

P 

pppp 

par-TAKE-FREE-ly 

Q 

QQqQ 

QUITE-HARD-to-SAY 

R 

rRr 

re-LA-ted 

S 

sss 

sau-sa-ges 

T 

T 

TAME 

U 

uuU 

un-a-WARE 

V 

vvvV 

ve-ry-re-MOTE 

W 

wWW 

with-OUT-WAR 

X 

XxxX 

X-cel-lent-MEN 

Y 

YyYY 

YEO-man-NO-MORE 

Z 

ZZzz 

ZO-OL-o-gy 

INSTITUTE  OF  RADIO  ENGI- 
NEERS' OCTOBER  MEETING. 

The  regular  monthly  meeting  of  the  In- 
stitute of  Radio  Engineers  held  at  the  En- 
gineering Societies  Building  on  October  3, 
1917,  was  attended  by  a  very  large  number 
of  Radio  men. 

The  paper  to  be  presented  was  on  the 
subject  of  "Radio  Telegraphy  in  competi- 


Type  of  Vacuum  Tube  Described  in  Mr. 
Moorehead's  Paper  Before  the  Institute  of 
Radio  Engineers  at  New  York.  Filament 
Grid  and  Wing  Are  All  Inclosed  in  Evacu- 
ated Vessel. 


tion  with  Wire  Telegraphy  Overland,"  but 
owing  to  a  censorship  at  the  last  moment, 
this  paper  had  to  be  set  aside  for  some 
future  time. 

Two  other  interesting  papers  were  read 
instead.  The  first  described  a  new  type  of 
Edison  storage  battery  for  the  "B"  current 
of  Audions  by  Miller  Reese  Hutchinson, 
and  the  second  the  "Manufacture  of  the 
Moorehead  Tube"  by  Prof.  Moorehead. 

Mr.  Hutchinson's  paper  covered  prin- 
cipally the  development  of  a  unit  of  storage 
batteries  which  would  supersede  the  use  of 
"flashlight  batteries"  for  the  high  voltage 
circuit,  which  would  be  compact,  reliable 
and  capable  of  withstanding  all  forms  of 
abuse  and  still  have  a  long  life  on  each 
charge. 

Mr.  Moorehead's  paper  dealt  with  the 
development  of  his  vacuum  tube,  the 
various  manufacturing  processes,  experi- 
ments, etc.  In  Figure  1  is  shown  the 
structure  of  the  tube,  the  grid  consisting 
of  a  copper  wire  coil  and  the  plate  of 
platinum,  while  the  filament  is  of  tungsten. 
Various  claims  were  made  for  the  success 
of  this  tube.  Another  type  is  shown  in 
Figure  2,  which  was  brought  out  to  get 
around  Dr.  de  Forest's  patents  evidently ; 
the  construction  being  the  same,  except 
that  a  strip  of  perforated  brass  gauze  is 
placed  around  the  outside  of  the  tube  for 
the  plate  terminal,  instead  of  inside  the 
rube. 

Both  papers  were  read  by  members  of 
the  Institute,  the  authors  not  being  present, 
and  therefore  queries  were  not  answered. 


Second  Type  of  Vacuum  Tube  Described  in 
Mr.  Moorehead's  Paper  on  the  Manufacture 
of    This    Class    of    Radio    Detectors.  Wing 
Terminal  Outside  of  Bulb. 


Very  little  discussion  took  place,  altho  some 
members  took  occasion  to  state  that  the 
Moorehead  tube  had  not  been  found,  in  their 
experience,  to  be  as  sensitive  as  the  Audion 
in  actual  tests. 


616 


ELECTRICAL  EXPERIMENTER 


January,  1918 


"Ham"  Aerials 


AERIALS?  Sure  we  know  what  they 
are,  you  mean  those  wires  strung  up 
in  the  air  on  top  of  the  house,  and  that 
in  some  way  or  other  send  and  receive 
electro-magnetic  waves,  or  at  least  did  be- 
fore the  order  to  remove  them  which  makes 
the  top  of  the  house  look  respectable  now, 
but  say,  between  you  and  me  and  the  lamp- 
post, an  aerial  is  the  cause  of  more  funny 
business  and  trouble  that  ever  was  visited 
on  the  poor  lads  that  take  up  wireless.  How 
so?  you  ask.  Well,  it  happened  this  way, 
at  least  in  my  experience, 
and  believe  me,  it  has  run 
from  anything  to  every- 
thing. 

To  start  this  line  of 
chatter  right,  I  should  say 
that  I  started  in  the 
"Ham"  class  somewhere 
along  the  middle  of  the 
year  1909,  and  of  course 
put  up  an  aerial  of  two 
aluminum  wires  forty  feet 
long  on  two  poles  ten  feet 
high,  nailed  to  the  chim- 
neys. But  it  so  happened 
that  I  had  nailed  said  poles 
to  the  type  of  chimneys 
that  have  a  nice  heavy 
granite  block  on  the  top, 
three  feet  by  one  and  one- 
half  feet,  and  of  course, 
desiring  to  have  the  aerial 
up  as  high  as  possible,  I 
had  only  allowed  the  pole 
to  over-lap  about  a  foot. 

The  reason  for  this  long 
description  is  apparent 
when  things  begin  to  hap- 
pen, and  things  did  start 
with  a  wallop.  It  began 
the  Saturday  afternoon 
that  Teddy  returned  from 
Africa  and  took  the  form 
of  a  beautiful  storm  right 
in  off  the  old  Atlantic. 
Barnum  and  Bailey's  Cir- 
cus was  flooded  while  it 
was  up  at  the  Polo 
Grounds  and  it  seemed  the 
animals  were  raising  the 
dickens  because  of  all  the 
things  Teddy  did  to  their 
friends  at  home.  The  wind 
blew  and  the  New  York 
City  College  had  a  bill  for 
a  new  flag  pole  the  very 
next  day.  By  all  the  laws 
of  Hamville  my  poles 
should  have  stayed  up,  but 
I  guess  they  wanted  to  do 
a  little  celebrating  on  their 
own  hook,  and  they  cer- 
tainly did,  for  one  pole 
goes  over,  and  from  the  previous  descrip- 
tion it  will  be  seen  that  the  pole  afcted  just 
like  a  big  lever,  thereby  prying  the  granite 
block  off,  letting  it  drop  a  mere  distance  of 
five  feet,  gaining  speed  and  weight  and 
ending  up  by  putting  a  hole  in  the  tin  roof, 
which,  of  course,  let  the  rain  in  and  our 
ceiling  looked  like  a  sponge. 

Lots  of  fun,  that  finished  off  with  an 
order  from  the  owner  of  the  house  that 
Willy  should  not  erect  any  more  aerials 
on  the  house  top.  Things  looked  gloomy 
alright  till  the  time  when  the  roof  was 
fixt  and  the  owner  discovered  that  the  house 
needed  a  chimney  of  tin  for  the  main  smoke 
outlet.  This  was  put  up  and  stood  some 
ten  feet  tall  with  plenty  of  guy  wires, 
which  of  course  did  not  worry  me  in  the 
least,  for  I  took  the  wires  off  of  the 
nails  and  put  tape  on  the  nails  before  put- 


By  W.  J.  HOWELL 

ting  the  wires  back  in  place,  and  signals 
came  in  just  about  the  same.  But  the  joke 
of  the  whole  thing  was  that  the  owner 
lived  on  the  ground  floor  and  shortly  after 
the  smoke  stack  was  put  up,  said  owner 
looks  up  the  airshaft,  sees  the  wires  from 
the  chimney,  gets  excited  and  sends  the 
janitor  up  to  cut  Willy's  aerial  that  hung  in 
the  well — I  mean  airshaft.  He  was  one  of 
those  rare  specimens  of  stupidity  and  cut  the 
wires  as  ordered  with  the  result  that  the 
house  blame  near  needed  a  new  chimney. 


"  .  .  .  Speaking  of  Using  Phoney  Stunts  for  Aerials  Reminds  Me  of  One 
Stunt  I  Tried.  This  Was  to  Put  Insulators  in  the  Wire  Clothes  Lines  on 
the  Roof  and  Use  Them  for  Sending  and  Receiving.  All  Went  Well  Till 
the  Maid  Got  the  Surprise  of  Her  Life.     Willie  Was  Calling  His  Pal— Via 

Wireless." 

This  was  my  clue  to  ask  the  owner  if  he 
would  be  so  kind  as  to  let  me  fix  the  same 
and  of  course  Amateurs  will  not  need  to 
ask  why. 

Another  stunt  I  tried  was  to  have  a  cur- 
tain roller  mounted  on  the  house  about 
six  feet  above  the  fire  escape  and  let  it 
take  up  the  aerial  of  four  wires  that  I  had 
rigged  up,  to  pull  out  on  the  clothes  line 
when  it  was  not  being  used.  This  worked, 
but  the  aerial  was  only  about  twenty  feet 
long  and  so  the  signals  did  not  come  in  very 
well  at  that  time,  altho  I  suppose  that  if  I 
had  had  the  "real  sets"  of  today,  I  should 
have  had  "phenom"  results.  After  this  idea 
I  tried  a  wire  forced  into  the  space  between 
the  porcelain  coping  on  the  top  of  the  brick 
walls  of  the  house  and  was  able  to  receive 
a  fair  amount  with  it.  These  experiments 
all  took  place  during  the  days  of  old  W.  A. 


and  N.  Y.  which  gave  us  amateurs  plenty 
of  juice  for  testing  purposes,  if  you  lived 
anywhere  in  the  vicinity  of  said  stations. 

Later  on  I  was  able  to  put  an  aerial  on 
the  house  next  door  and  it  was  some  an- 
tenna, believe  me.  Forty  feet  long,  spread- 
ers four  feet  and  had  four  wires,  these 
being  strung  about  ten  feet  above  the  roof, 
one  end  hooked  to  a  sky-light  and  the  other 
to  the  top  of  a  dumb-waiter  shaft.  I  was 
in  luck  when  I  could  get  "Key  West"  on 
palena  with  home-made  instruments  and 
seventy  -  five  ohms  built 
into  the  craziest  pair  of 
ear-laps  you  ever  saw. 
Things  went  along  fine 
until  something  happened 
and  the  aerial  pulled  or 
tript  one  of  the  Navy 
Yard's  messages  and  I  had 
a  fanlight  to  pay  for.  Oh, 
it's  a  great  life  if  your 
aerial  don't  come  down. 

After  a  while  I  became 
acquainted    with    a  chap 
who  lived  about  four  hun- 
dred feet  away  and  we  put 
up  a  wire  for  telephone 
and  telegraph  work.  The 
results  were  fine  and  the 
wire  also  acted  as  a  great 
aerial ;   in   fact,   we  even 
went  so  far  as  to  be  able 
to  both  receive  at  the  same 
time  and  talk  about  the 
way  the  fellow  was  send- 
ing by  using  the  telephone, 
altho  situated  two  blocks 
apart.    Along  about  that 
time  Sayville  began  send- 
ing press  at  fifteen  words 
per    minute,    which  was 
then  about  the  speed  limit 
of  yours  truly,  while  my 
friend    was    right  there 
when  it  came  to  copying 
WHB  at  about  twenty  to 
twenty  -  five    per  minute. 
Now  both  stations  had  the 
dodgasted  habit  of  sending 
at  the  same  time  and  gen- 
erally the  stuff  was  differ- 
ent, so  by  sticking  a  vari- 
able   condenser     in  the 
ground    wire    my  friend 
was  able  to  tune  to  600 
meters  for  WHB  and  I 
got  Sayville  on  about  1800 
meters,  and  if  I  remember 
rightly,  at  the  same  time, 
so  nothing  was  mist.  Of 
course,  if  either  of  us  va- 
ried our  tuning  arrange- 
ment, it  threw  the  other 
fellow  out  a  little,  but  this 
was  easily  overcome  by  trial  and  then  leav- 
ing the  set  tuned.    One  advantage  at  the 
time  was  that  the  other  chap  could  not 
tune  up  to  Sayville,  so  if  he  wanted  to 
copy  the  stuff,  I  used  to  receive  it  on  my 
set,  still  using  the  'phone  wire  and  then 
hold  the  receiver  to  the  transmitter  for  him 
to  hear.    Talk  about  duplex  working  and 
phoney  stuff,  we  had  the  time  of  our  lives 
monkeying  with  that  wire  strung  along  the 
edges  of  the  roof. 

Putting  up  aerial  masts  seems  to  be  my 
middle  name  and  I  have  gone  thru  the 
stages  of  the  game  where  Willy  goes  up  on 
the  roof  every  five  minutes  to  look  at  his 
wires  (and  the  more  he  has  the  better),  to 
the  point  where  one  lonely  wire  constitutes 
the  antenna  and  the  only  time  I've  looked 
at.it  was  when  stuff  didn't  come  in. 
(Continued  on  page  651) 


\ 


January,  1918 


ELECTRICAL  EXPERIMENTER 


61  7 


A  Mechanical  Inductance  Changer 


By  FREDERICK  J.  SCHLINK 


WHEN  listening  for  various  radio  sta- 
tions we  find  that  it  is  necessary  to 
continually   shift   our   tuning  coil 
sliders  or  switches,  so  that  we  may  hear  the 
different  wave  length  signals.  This  manipula- 
tion is  necessary  since  the  law  requires  that 


Front  View  of  Motor-Driven  Inductance  Tun- 
ing Switch  as  Fitted  in  Lower  Left  Corner  of 
Standard  Radio  Receiving  Cabinet. 


the  transmitting  apparatus  radiate  sharp 
waves  and  we  find  that  each  station  "comes 
in"  at  sharply  defined  points  of  the  tuning 
coil;  the  usual  "stand-bi"  being  of  little  or 
no  use  and  resort  is  had  to  the  continual 
changing  of  the  tuning  coil  switches  or 
sliders. 

This  operation  soon  becomes  tiresome 
and  will  never  give  the  satisfaction  that 
is  to  be  had  by  the  use  of  a  mechanical  in- 
ductance changer.  The  following  plan 
has  given  far  more  satisfaction  than  was 
really  expected  of  it. 

A  tuning  coil  was  made  separate  from 
the  usual  receptive  apparatus  and  was  tapt 
off  in  the  usual  manner,  making  30  points 
to  three  (3)  turns  each,  using  wire  of  size 
No.  22  or  larger.  The  cylinder  on  which 
the  wire  was  wound  is  four  inches  in  di- 
ameter and  fourteen  inches  long,  and  this 
amount  of  wire  and  method  of  tapping 
has  proved  ample  for  the  usual  amateur 
and  commercial  stations.  There  is  of 
course  no  unusual  difficulty  presented  in 
adding  more  wire  or  switch-points  or  con- 
forming to  any  other  method  of  tapping. 

This  tuner,  while  incorporated  in  the 
case  of  the  regular  receiving  apparatus,  is 
not  connected  to  form  a  permanent  part 
of  the  receiving  circuit  for  the  reason  that 
it  would  offer  some  difficulty  to  the  manual 
changing  of  the  inductance,  in  that  it  does 
not  partake  of  the  advantages  to  be  had  by 
the  use  of  the  "dead  end"  arrangement. 
This  device  is  used  only  for  the  purpose 
of  finding  the  various  stations  after  which 
the  apparatus  is  disconnected  by  the  switch 
A,  Fig.  1,  and  found  again  on  the  regular 
receiving  apparatus.  This  change  is  very 
quickly  accomplisht  and  one  soon  learns 
just  about  where  a  particular  point  on  the 
auxiliary  coil  can  be  found  on  the  regular 
receiving  coil,  if  calibrated  or  simple  num- 
bered scales  are  used  on  the  tuners  and 
condensers. 

The  tuner  was  connected  in  the  usual 
manner  to  the  switch  points  and  the  hour- 
hand  shaft  of  an  ordinary  eight-day  clock 
was  projected  thru  the  front  of  the  case, 
the  switch  arm  having  been  mounted  di- 
rectly on  it  by  soldering.  It  is  suggested 
that  the  current  be  lead  to  the  switch-arm 
thru  the  washer  upon  which  the  switch- 
arm  moves ;  this  precaution  is  for  the  pur- 
pose of  obviating  any  imperfect  contacts 


that  might  result  if  the  current  is  brought 
to  the  switch-arm  thru  the  clock-work  and 
hence  thru  the  bearings  to  the  arm ;  it  is 
quite  easy  to  solder  the  lead  to  the  washer 
and  also  to  the  clock-work. 

The  clock  was  dismantled  and  the  un- 
necessary mechanism  was  removed,  that 
is  to  say,  the  alarm  movements,  the  small 
spring  on  the  balance  wheel  and  the  escape- 
ment movements.  A  small  vane  or  wind- 
break was  constructed  of  a  piece  of  num- 
ber 20  or  22  B.  &  S.  wire,  bent  as  shown 
in  Fig.  2.  This  vane  was  then  covered 
with  silk.  The  vane  is  for  the  purpose  of 
making  the  clock-work  unwind  slowly  and 
steadily  and  if  after  constructing  the  ap- 
paratus it  is  found  that  the  switch  revolves 
too  fast  or  too  slowly  the  remedy  lies  in 
making  the  vane  larger  or  smaller. 

It  will  be  necessary  to  bore  a  small  hole 
in  the  switch  face  thru  which  the  winding 
stem  of  the  clock-work  will  project;  this 
hole  should  be  a  little  larger  than  the  wind- 
ing stem  so  that  the  key  may  be  inserted. 

It  will  be  noticed  that  in  most  clock- 
work mechanisms  that  the  shaft  of  the  bal- 
ance wheel  projects  beyond  the  brass  frame 
of  the  work  and  to  this  protruding  shaft 
the  vane  must  be  soldered.  This  soldering 
may  be  accomplished  by  forcing  a  sheet 
of  thin  paper  over  the  little  shaft  pro- 
jection and  then  soldering  the  wire  of  the 
vane  to  the  shaft  using  a  drop  of  acid,  a 
bit  of  solder  and  a  small  soldering  iron. 
The  purpose  of  the  sheet  of  paper  is  to 
prevent  the  solder  from  joining  the  frame, 
vane  and  shaft  together  which  it  will  do 
if  this  precaution  is  not  taken.  It  may  be 
possible  in  some  clocks  to  mount  the  vane 
within  the  works,  which-  method  is  to  be 
preferred.  In  some  types  of  clock-work 
the  winding  stem  is  on  the  opposite  side 
from  the  dial  side  and  some  ingenuity 
must  be  displayed  so  that  the  clock-work 
may  be  wound  up. 

Some  kind  of  a  motor  stop  must  be  pro- 
vided and  here  again  the  method  of  con- 
struction will  differ  with  the  various  types 
of  clocks ;  a  light  lever  arrangement  that 
will  slip  between  the  revolving  blades  of 
the  vane  may  be  sufficient. 

The  operation  of  the  apparatus  is  sim- 
plicity itself :  Have  all  inductances  of  the 
regular  receiving  apparatus  at  zero  unless 
your  aerial  has  a  small  natural  wave  length, 


Diagram  Showing  How  the  Motor  Switch  Is 
Connected  for  Broad  Wave  Tuning  in  Picking 
Up  a  Station;  Once  the  Station  Is  Heard,  It 
Is  Tuned  in  Sharply  on   Usual  Instruments. 


in  which  case  it  will  be  necessary  to  leave 
in  some  inductance  of  the  loading  coil,  the 
amount   of   which   will   have   to   be  de- 


termined by  experiment.  The  condenser 
capacity  will  also  have  to  be  determined 
experimentally.  Start  the  motor  (clock- 
work) and  "listen  in"  when  any  station 
or  some  desired  station  is  sending,  close 
switch  (A),  stop  motor,  and  tune  in  sta- 
tion on  regular  receiving  apparatus. 


This  View  of  Mechanical  Inductance  Changer 
Shows  How  Clock-Work  (or  Other  Motor)  I* 
Fitted  Inside  Cabinet. 


ANENT  THE  HELMHOLTZ  RE- 
SONATOR AS  RADIO  AMPLIFIER. 

The  application  of  the  Helmholtz  Reson- 
ator to  radio  work  as  described  on  page 
266  of  the  August  "E.  E."  had  occupied 
some  little  of  my  time  before  the  declara- 
tion of  war,  and  in  addition  to  its  use  as  an 
amplifier  as  described,  I  found  that  even 
more  important  and  useful  is  the  effect  that 
it  has  on  interference  of  any  kind. 

The  resonator  transmits  and  amplifies 
sound  waves  of  its  own  frequency,  only. 
Hence  any  sound  waves  in  the  radio  re- 
ceiver differing  in  frequency  from  that  of 
the  resonator  will  not  pass  thru  it.  For 
example :  say  we  have  a  resonator  respon- 
sive to  sound  waves  having  a  frequency  of 
500  cycles ;  we  put  this  on  a  radio  receiver 
in  which  a  number  of  stations,  including  a 
500  cycle  set,  are  coming  in,  and  in  which, 
as  well,  considerable  static  is  present.  Static 
having  a  low,  scratchy  pitch  will  be  ex- 
cluded from  the  ear  by  the  resonator,  and 
signals  of  any  station  which  does  not  have 
a  spark  tone  frequency  of  500  will  also  be 
excluded.  The  500  set  which  you  desired 
to  copy  will  be  all  that  you  will  hear  thru 
the  resonator  and  his  signals  will  be  some- 
what louder  than  in  the  'phones,  due  to  its 
amplifying  property. 

I  have  been  able  to  receive  a  friend's  sta- 
tion excellently  thru  the  worst  QRM  and 
static  by  having  him  vary  his  rotary  until 
his  spark  pitch  was  in  tune  with,  or  at  the 
same  frequency  with  the  resonator  I  was 
using.  The  only  disadvantage  is  that  the 
combination  of  'phone  and  resonator  can 
not  be  clasped  to  the  ears  as  receivers  are, 
but  must  be  set  on  a  table ;  making  it  a  very 
uncomfortable  position  for  the  listener. 
Now  who  will  make  some  practical  im- 
provement of  this  scheme  so  that  the 
resonator  and  'phone  may  be  made  in  one 
unit  and  fastened  to  the  head,  receiver- 
fashion  ;  and  so  cause  it  to  be  of  real 
value  to  the  wireless  field? 

Contributed  by  H.  O.  BIXBY. 


RADIO  EXPERTS  WANTED! 
To  write  up  your  new  ideas  and  ap- 
paratus which  have  proven  efficient  and 
practical.  Send  us  a  short,  clear  write- 
up  with  sketches  and  photographs  when 
possible.  We  pay  good  rates  for  all 
articles  accepted.  Address  the  Editor 
"Radio  Department." 


618 


ELECTRICAL  EXPERIMENTER 


January,  1918 


A  HIGH  POTENTIAL  STORAGE 
BATTERY. 
By  Thomas  Lewis  Herren. 
(University  of  Chattanooga.) 
The  chief  drawback  of  the  vacuum  valve 
detector  to  the  average  amateur  is  the  cost 


,l£oa . 


Fig  l 


9  ° 

o 

o 

o 

o 

o 

o  o 

o 

o 

o 

o 

o 

o 

o  o 

o 

Fig.  2 


IP 


I  t 
^  C 


bp* 


Fig  5  20re$'c/ 


For  Those  Who  Do  Not  Have  Available  a  Direct  Current 
Source  For  Operating  Audions  on,  This  Small  High- 
Voltage  Storage  Battery  Will  Prove  of  Valuable  Service. 
It  Can  Be  Charged  from  a  Small  D.  C.  Dynamo  or  from 
Gravity  (Blue-stone)  Cells. 


ing  purposes.    The  material  required  for 

it  is  as  follows : 

(20)  3/4  inch  X  7  inch  test  tubes 
18  strips  of  lead  shaped  as  shown  in 
Fig.  3 

4  strips  of  lead  shaped  as  shown  in 
Fig.  4 

1  rack  or  frame  as  shown  in 

Fig.  1  and  2. 
Enough  solution  of  25%  sul- 
furic acid  and  75%  water  (by 
bulk)  to  fill  the  tubes  within 
inch  of  the  top.  In  mixing 
the  sulfuric  acid  and  water  al- 
ways pour  the  acad  into  the 
water,  stirring  vigorously  with 
a  glass  rod  meanwhile.  The 
lead  strips  are  fastened  to  the 
top  strip  of  the  frame  by  means 
of  brass  machine  screws  and 
nuts.  Taps  are  taken  from 
there  to  a  multi-point  switch 
conveniently  located.  The  rack 
may  be  put  together  with  small 
brass  screws  and  glue.  After 
the  battery  is  assembled,  it  is 
ready  for  charging,  which  may 
be  done  by  a  small  dynamo  of 
about  two  amperes  output. 
With  a  charging  current  of 
two  amperes,  the  charge  will 
be  completed  in  about  15  min- 
utes ;  with  one  ampere  in  about 
thirty  minutes.  It  can  also  be 
charged  by  means  of  an  elec- 
trolytic rectifier.  This  battery 
with  usual  care  will  give  very 
efficient  results  and  will  last  a 
number  of  years.  It  is  only  nec- 
essary to  charge  it  about  every 
three  or  four  months,  and 
sometimes  less  than  that. 


F/g4  4regd  0 


and  upkeep  of  the  high  potential  battery, 
which  usually  consists  of  10  or  12  flash- 
light batteries.  The  writer  here  describes 
a  high  potential  storage  battery  which  has 
proved  to  be  very  efficient  when  used  in 
connection  with  a  vacuum  valve,  for  test- 

ROTARY  ADJUSTMENT  FOR 
SECONDARY  OF  COUPLER. 

Many  amateurs  wish  to  make  cabinet  re- 
ceiving sets,  but  hesitate  to  do  so  because 
there  is  difficulty  in  the  coupling  adjust- 
ment of  the  secondary. 

As  every  amateur  knows,  the  method  of 
bringing  the  adjusting  rod  thru  the  end  of 
the  cabinet  is  not  satisfactory,  as  it  bends 
easily  and  causes  no  end  of  trouble.  If 
they  build  their  couplers  as  shown  they 
can  have  rotary  adjustment  and  it  is  very 
simple. 

But  little  explanation  need  be  given,  as 
the  sketches  explain  everything.   This  much 


With   This  Simple   Lever   Attachment  Any 
Loose  Coupler  Secondary  May  Be  Controlled 
from  a  Rotary  Knob. 

may  be  said,  however;  make  the  angle 
bracket  A  out  of  very  heavy  brass,  as  this 
must  stand  all  the  strain.  A  scale  may  be 
placed  on  the  outside  of  the  panel  and  very 
close  adjustment  is  possible. 
Contributed  by   HOWARD  STORCK. 


METHOD  FOR  INCREASING  SEN- 
SITIVENESS OF  SILICON  AND 
GALENA. 

I  have  found  that  silicon  may  be  rendered 
considerably  more  sensitive  for  use  as  a 
radio  detector  when  treated  as  follows : 

Place  the  piece  of  silicon  in  a  boiling 
solution  of  caustic  soda   (sodium  hydro- 
oxid)    and  boil   for  about   five  minutes. 
The  solution  should  be  about  10%  strength. 
Remove  from  the  soda  and  wash  well,  in  five 
or  six  changes  of  BOILING  water.  Place 
in  a  solution  of  hydrochloric  acid,  made  by 
mixing  one  part  of  strong  acid  with  one 
part  of  water.    Boil  for  about  fifteen  min- 
utes.   If  the  liquid  is  strongly  colored  re- 
peat the  operation.    Wash  the  silicon  well 
with  hot  water  several  times,  then  rinse 
with  pure  alcohol  and  dry.    The  pieces  of 
silicon  so  treated  should  be  kent  in  a  closed 
bottle  and  should  not  be  handled  more  than 
is  necessary.    I  have  treated  silicon  that 
would  not  work  as  described  with  excellent 
results. 

To  render  galena  more  sensitive  and  also 
to  resensitize  a  piece  which  is  no  longer 
useful,  boil  a  piece  of  the  mineral  in  a 
strong  solution  of  ammonium  acetate  [N 
H42  C;  H3  02]  for  about  fifteen  or  twenty 
minutes.  Pour  off  the  liquid  and  boil  sev- 
eral times  with  water,  pouring  off  the  water 
each  time,  then  wash  with  alcohol  and  dry. 
Keep  in  stoppered  bottles.  To  make  am- 
monium acetate  solution,  take  one  ounce 
strong  ammonia  water  and  one  ounce  of 
water  and  add  to  it  acetic  acid  in  such 
amount,  stirring  constantly,  until  the  odor  of 
ammonia  has  gone. 

Contributed  by  ROBERT  W.  JAEGER. 


THE  SIMPLEST  SPINTHARISCOPE. 

Herewith  is  a  description  of  a  simple 
spinthariscope.  It  is  composed  of  a  "Radio- 
lite"  watch  and  a  microscope.    Focus  the 


microscope  on  one  of  the  numbers  on  the 
dial  and  you  can  see  the  emanation  from  the 
radium  in  the  letters,  striking  the  zinc 
sulfid.  The  stronger  the  microscope  the 
better  it  works,  but  it  must  be  in  the  dark 
Contributed  by  BURLEIGH  GARDNER. 

SCALES  FOR  TUNING  COILS. 

Finding  that  a  scale  on  a  tuning  coil  is 
of  great  advantage  in  locating  stations,  I 


This  Precision  Slider  Indicator  and  Gradu- 
ated Scale  Will  Enhance  the  Value  of  Any 
Tuning  Coil  Many  Times. 

am  submitting  the  idea  for  the  benefit  of 
some  other  amateurs. 

The  scale  may  be  made  of  thin  sheet  brass 
covered  with  white  paper  and  should  be 
about  half  an  inch  wide  and  as  long  as  the 
tuner.  It  is  fastened  at  the  side  of  the 
slider  rod  and  the  slider  is  equipt  with  a 
pointer,  also  made  of  brass,  to  move  over 
the  scale.  The  paper  scales  are  very  well 
pasted  on  tin  strips  to  hold  them  rigid.  The 
slider  indicator  is  unique,  the  point  itself 
being  drilled  and  filed  to  leave  an  opening 
as  shown — giving  a  precision  form  of 
needle,  similar  to  that  used  on  commercial 
instruments.  When  a  station  is  tuned  in, 
and  after  listening  a  while,  the  operator  de- 
sires to  tune  in  others,  the  number  at  which 
the  pointer  points  is  noted,  and  after  listen- 
ing to  others,  if  the  operator  wishes  to  tune 
;n  the  first  one,  all  that  is  necessary  is  to 
move  the  pointer  back  to  the  number  it 
pointed  to  before  and  the  station  is  in  tune, 
without  waste  of  time  in  relocating  it 

Contributed  by       SCOTT  E.  VANCE. 


MAKING  A  SPARK  COIL  MORE 
EFFICIENT. 

A  novel  way  to  make  your  spark  coil 
give  a  much  larger  spark  than  usual  is  de- 
scribed   below    and    can    be    done  very 

easily. 

Secure  an  elastic  band  and  wind  it 
around  the  top  of  the  vibrator  and  the 
other  end  of  the  band  around  the  thumb 
screw  (the  band  should  be  tight).  It  will 
be  found  that  the  vibrator  has  been  pulled 
back  toward  the  thumb  screw,  thereby  mak- 


/ron  core 


Elasf/c  Son  a 


Y/tra/or 


To  Obtain  a   Higher  Pitch  from  Ordinary 
Spark  Coil  Vibrators,  Simply  Snap  a  Rubber 
Band    Over    End    of   Vibrator   Spring  and 
Bridge. 

ing  a  larger  and  more  musical  spark  be- 
cause the  spring  is  stiffer. 
Contributed  by  AN  EXPERIMENTER. 


January,   1918  ELECTRICAL   EXPERIMENTER  619 

Useful  Hints  on  Electric  Motor  and  Dynamo  Testing 


UNDOUTEDLY  many  of  the  readers 
would  like  to  know  how  small  elec- 
tric motors  and  dynamos  are  tested. 
It  is  the  purpose  of  this  article  to  show  how 
it  is  done.  With  small  machines  it  is  not 
practicable  to  test  the  same  way  as  one 
would  a  large  machine.  This  article  will 
deal  with  generators  or  motors  below  V\ 
H.P.  capacity. 

The  first  procedure  is  to  test  the  arma- 
ture and  field  windings  for  continuity.  This 
is  done  by  means  of  a  galvanometer  or 
telephone  receiver.  The  indicating  device 
is  connected  in  series  with  the  coil  and  bat- 
teries as  shown  in  Fig.  1.  If  the  coil  is 
not  broken,  the  galvanometer  needle  will 
deflect  to  one  side,  when  the  circuit  is  com- 
pleted. Next,  we  have  the  test  for  leak- 
age, that  is,  whether  any  part  of  the  wind- 
ing touches  the  frame.  Join  the  wire  from 
the  galvanometer  or  receiver  to  the  frame, 
while  the  other  wire  of  the  battery  connects 
to  the  coil ;  if  there  is  no  movement  of  the 
needle  when  the  circuit  is  closed,  there  is  no 
leakage  and  the  insulation  of  this  particular 
winding  is  perfect.  But  if  a  very  slight  click 
or  movement  of  the  needle  is  observed,  this 
may  be  due  to  the  dampness  in  the  insula- 
tion, which  cannot  be  helped. 

The  commutator  should  now  be  tested 
with  the  battery  and  indicating  instrument, 
in  order  to  see  that  each  segment  is  not 
short-circuited  with  its  neighbor.  This  is 
best  done  by  attaching  one  wire  of  the 
battery  to  one  segment  and  the  other  wire 
of  the  galvanometer  to  the  adjacent  one; 
watch  for  any  movement  of  the  needle.  If 
none  occurs,  it  indicates  that  the  segments 
are  not  touching.  Each  and  every  one  of 
them  should  be  tested  in  the  same  manner. 
It  is  advisable  to  test  the  resistance  of  each 
coil  in  order  to  find  out  that  they  have  the 
same  amount  of  wire,  providing  that  they 
are  wound  with  the  same  gage.  If  the 
commutator  and  the  brushes  are  clean,  their 
resistance  will  be  infinitesimal  in  compari- 
son with  the  coils  and  therefore  it  may  be 
neglected.  The  general  method  is  to  con- 
nect each  coil  thru  its  corresponding  seg- 
ment to  a  Wheatstone  bridge,  either  of  the 
arm  or  box  type.  Instructions  for  the  use 
of  this  instrument  are  to  be  found  in  any 
up-to-date  electrical  book.  If  a  bridge  is 
not  at  hand  the  volt  and  ammeter  method 
can  be  successfully  employed  and  connec- 
tions for  using  them  are  given  in  Fig.  2. 
Connect  as  shown  and  take  simultaneous 
readings  on  both  instruments.  After  the 
readings  are  obtained,  they  should  be  next 

E 

substituted  in  the  equation  R  =  —  (Ohm's 

I 

law)  where  R  is  resistance  of  winding  in 
ohms,  I  current  in  amperes  and  E  voltage 
drop  across  winding.  Two  values  of  I  and 
E  are  known  and  the  third  R  is  obtained  by 
solving  the  equation.  Every  coil  should  be 
tested  in  a  similar  manner. 

The  various  parts  having  been  tested,  the 
next  step  is  to  test  the  complete  machine. 
In  the  first  place  it  should  be  firmly  screwed 
or  bolted  down  and  the  bearings  well  oiled, 
the  belt  tightened,  the  brushes  properly 
placed  and  making  good  contact  with  the 
commutator  and  see  that  all  connections 
are  firmly  and  properly  made.  The  field 
coils  should  be  tested  for  their  proper 
polarity  with  a  compass  needle.  If  it  is 
found  that  they  possess  the  same  polarity, 
one  of  them  must  be  oppositely  connected 
or  else  remagnetized  by  passing  a  power- 
ful current  thru  them. 

In  testing  motors,  a  volt  and  ammeter 


By  SAMUEL  COHEN 

will  be  required  and  also  a  prony  brake,  a 
frictional  device  for  testing  the  horse-power 
developed  by  a^  running  machine.  The  in- 
struments are  connected  as  indicated  in 
Fig.  3.  The  speed  is  also  taken  in  these 
tests  and  this  can  be  obtained  by  using  a 
speedometer,  which  can  be  obtained  at  any 
hardware  or  machinery  supply  store.  Fig. 
4  illustrates  a  simple  prony  brake.  It  con- 
sists of  two  wooden  blocks  clamped  on  the 
motor  pulley  by  means  of  two  small  bolts. 
The  small  weight  "W"  on  the  right  is  to 
counter-balance  the  longer  arm,  and  should 
be  adjusted  until  the  brake  is  perfectly 
balanced  on  the  pulley.  This  is  very  impor- 
tant. When  the  perfect  balance  is  obtained 
the  two  bolts  must  be  tightened,  by  turning 
the  hand  nuts,  until  the  brake  begins  to 
clamp  the  pulley.  When  the  machine  is 
running,  the  nuts  are  tightened,  and  a 
weight  "W  A"  is  then  added.  This  weight 
is  increased  in  order  to  keep  the  brake 
balanced.  As  soon  as  the  brake  is  balanced 
during  the  maximum  run  of  the  motor,  the 


horse-power  is  then  obtained  just  by  multi- 
plying the  R.  P.  M.  of  the  speedometer 
reading,  by  the  distance  "D"  in  feet,  times 
the  weight  in  pounds  (W  A)  and  then  by 
the  factor  .000194.  The  horse-power  can 
also  be  measured  directly  by  means  of  the 
prony  brake,  by  first  loading  the  arm  with 
a  weight  and  clamping  the  brake  on  to  the 
pulley  firmly,  then  gradually  increasing 
the  speed  of  the  motor  and  the  longer  arm 
placed  upon  a  spring  balance  or  scale.  The 
former  method  is  more  practical  for  smaller 
machines  as  the  power  developed  by  them 
is  very  small. 

The  efficiency  of  a  motor  can  be  readily 
obtained  by  knowing  the  input  in  watts; 
that  is,  volts  times  amperes,  and  the  power 
developed  in  watts.  Then  divide  the  latter 
by  the  former  and  the  result  obtained  is 
the  efficiency  of  your  machine. 

The  result  obtained  in  the  prony  brake 
test  is  in  foot-pounds  per  minute,  and  to 
convert  it  into  watts,  it  is  necessary  to 
divide  the  quantity  obtained  by  44.24. 

In  the  case  of  testing  a  dynamo,  some 
means  must  be  made  for  absorbing  the 
power  generated,  the  same  as  the  prony 


brake  absorbs  the  power  developed  by  the 
motor.  A  lamp  bank,  made  up  of  miniature 
incandescent  electric  lamps  or  a  water  re- 
sistance will  be  needed  for  the  absorption 
of  the  current.  An  ammeter  should  be 
connected  in  series  with  the  lamp  bank 
or  water  resistance,  a  voltmeter  shunted 
across  the  dynamo  brushes  and  a  double- 
pole  switch  as  indicated  in  Fig.  5.  Now  run 
the  machine  up  to  speed  and  then  close  the 
switch  and  regulate  the  resistance  until  the 
meters  indicate  the  maximum  output 
at  which  the  machine  is  rated.  If  the  ma- 
chine is  of  unknown  output  then  regulate 
the  speed  and  load  to  the  point  where  the 
maximum  watts  output  is  obtained  with 
only  slight  heating  of  the  machine.  It 
should  be  kept  running  for  one-half  hour 
and  the  speed  recorded  every  five  or  seven 
minutes. 

If  the  machine  fails  to  generate,  altho 
connections  are  properly  made,  the  direc- 
tion of  rotation  should  be  reversed  or  the 
position  of  the  brushes  altered.    If  all  these 


arrangements  do  not  help,  the  only  remedy 
is  to  remagnetize  the  field  with  some  sepa- 
rate source  of  current  until  they  are  partial- 
ly magnetized.  Sparking  at  the  commuta- 
tor should  be  eliminated  as  much  as  pos- 
sible; there  are  several  causes  for  this,  such 
as  loose  connections,  dirty  brushes,  short- 
circuits,  over-loading  of  the  brushes,  over- 
loading the  machine  and  worn-out  bearings. 

The  efficiency  of  a  dynamo  can  be  ob- 
tained in  the  same  manner  as  in  the  motor. 
The  efficiency  equals  the  electrical  output 
divided  by  the  mechanical  input.  To  illus- 
trate this,  let  us  take  a  typical  example: 
suppose  that  a  dynamo  of  150  watts  capa- 
city requires  a  motor  of  y2  H.P.  to  drive 
it.  What  is  the  efficiency  of  the  generator 
at  its  maximum  load?  The  solution  is  as 
follows : — there  are  746  watts  in  one  H.P. 
therefore,  y2  H.  P.  373  watts;  divide  this 
into  150  watts  which  result  is  .42  and  in 
terms  of  percentage,  (i,  e.,  multiplied  by 
100)  42  per  cent  is  the  efficiency  of  that 
particular  dynamo.  The  larger  the  machine 
the  higher  is  the  efficiency.  The  electrical 
output  is  obtained  from  the  volt  and  am- 
meter readings. 


The  Present  Discussion,  With  the  Aid  of  the  Accompanying  Diagrams,  Aims  to  Bring  Out  the 
Fundamental  Tests  to  be  Made  On  Motors  and  Dynamos,  Both  Large  and  Small.  Every 
Radio   Operator,    Electrician   and    Experimenter   Must    Be   Thoroly    Familiar   With  These 
Principles,  For  They  Are  In  Daily  Application  In  Every  Branch  of  the  Art. 


620 


ELECTRICAL  EXPERIMENTER 


January,  1918 


W  C2N5TRV1QTER 


Experimental  Mechanics 


THE  mechanical  and  electrical  ama- 
teurs of  today  are  far  better  off  than 
their  ancestorial  fellow  amateurs 
who  have  bitterly  strived  in  build- 
ing their  models  without  real  tools. 
This  of  course  was  a  great  drawback  in 


Fig.  2.  A  Very  Satisfactory  Work-shop 
Power  Unit,  Comprising  An  Air-cooled  Gaso- 
line Engine  Rated  At  Vs  H.P.  It  Is  Belted  to 
the  Line  Shaft.  Two  Small  Dynamos  Can  Be 
Seen  Just  Back  of  the  Engine. 

respect  to  rapid  developments  of  certain 
devices  which  they  were  working  with. 
However,  the  present  day  experimenter 
has  the  greatest  mechanical  facilities  which 
he  can  utilize  in  the  making  of  his  various 
models.  It  is  often  found,  however,  that 
the  experimenter  with  the  greatest  facilities 
on  hand  is  unable  to  go  ^^^^^^^^^ 
forward  with  his  ideas  be- 
cause  of  lack  of  proper 
equipment  as  he  is  un- 
familiar with  the  tools, 
and  the  kind  that  he  is  re- 
quired to  purchase.  On 
the  other  hand,  many 
amateurs  who  possess  a 
number  of  tools  and  other 
equipment  are  unable  to 
obtain  best  results  there- 
from on  account  of  lack 
of  ability  to  handle  them. 

Another  great  draw- 
back which  the  amateur 
had  to  contend  with  is  with 
the  improper  layout  of 
shop  and  laboratory  equip- 
ment and  which  case  was 
noticed  in  the  Amateur  n„m»_^^^_ 
Contest  page  of  this  jour- 
nal, and  the  various  inquiries  which  the 
Editors  have  received.  For  the  above  rea- 
sons the  author  has  endeavored  to  bring 
forth  this  series  of  lessons  in  order  to  indi- 
cate to  the  reader  how  to  rig  up  a  shop  and 


By  SAMUEL  COHEN 
LESSON  I. 

laboratory  so  he  can  acquire  the  best  meth- 
ods of  handling  the  more  important  tools. 

The  first  and  most  important  thing  that 
the  novice  should  consider  is  to  obtain  a 
fairly  large  room  with  plenty  of  light  and 
sufficient  ventilation.  A  room  with  the 
dimensions  of  20  feet  deep  by  10  feet  wide 
is  just  the  size  which  would  prove  an 
ideal  room  and  Fig.  1  shows  a  general  lay- 
out of  the  various  parts. 

Of  course,  it  is  not  compulsory  to  fol- 
low exactly  the  same  layout  since  each  one 
will  be  controlled  by  his  resources  and 
location.  The  lighting  of  the  various  por- 
tions of  the  shop  should  be  either  by  elec- 
tricity or  gas;  electric  light  being  usually 
found  in  most  of  the  homes  of  amateur 
mechanics. 

It  is  presupposed  that  the  reader  has  a 
fair  knowledge  of  carpentry  thus  enabling 
him  to  construct  the  various  shelves  and 
benches.  The  most  important  one  is  the 
shop  bench  which  is  made  from  1  inch 
stock  and  measures  7  feet  long  by  2  feet 
wide.  The  legs  should  be  made  of  heavy 
square  timber  and  3x3  inches  is  quite 
ample.  Nails  should  not  be  used  in  join- 
ing the  various  sections ;  use  ample  large 
size  wood  screws.  Shelves  should  be 
placed  in  convenient  locations.  The  tool 
cabinet  may  be  of  the  drawer  type  which 
can  be  utilized  for  holding  various  measur- 
ing tools  and  different  sizes  of  drills,  taps 
and  dies,  etc. 

In  selecting  the  various  tools  necessary 
to  carry  on  the  shop  work  it  is  advisable 
for  the  novice  to  write  several  of  the  best 
toolmaking  concerns  for  catalogs,  in  order 
to  obtain  the  best  idea  as  to  prices  and 
quality  of  the  goods. 

Let  us  consider  that  the  reader  has  ac- 
quired a  good  judgment  as  to  the  company 
from  which  he  would  purchase  his  tools. 
The  first  tool  he  should  obtain  is  a  good 
vise,  which  should  be  of  the  parallel  jaw 


auxiliary  lead  jaws  and  the  latter  with  cop- 
per ones.  It  is  advisable  that  the  vises  be 
so  mounted  that  the  operator  can  work  with 
the  smaller  one  while  sitting  down. 

The  next  important  tool  is  the  lathe  and 
in  this  case  great  care  must  be  exercised 


In  opening  our  new  department,  "Experimental  Mechanics,"  we  do 
so  with  the  full  conviction  that  it  will  be  welcomed  enthusiastically  by 
the  majority  of  our  readers. 

Mechanics  and  electricity  are  so  closely  interwoven  today,  that  neither 
can  possibly  do  without  the  other.  Too  many  experimenters  and 
amateurs  are  dependent  these  days  upon  machine  shops,  cabinet  makers, 
tinsmiths,  etc.,  when  wishing  to  build  certain  new  apparatus  or  instru- 
ments. Every  amateur  experimenter  should  be  able  to  build  his  entire 
"rinktum"  right  at  home,  without  outside  help. 

And  by  studying  the  lessons  of  our  new  course,  he  will  be  placed  in 
a  position  whereby  he  will  accomplish  this  end— and  much  more.  Thous- 
ands of  very  lucrative  positions  are  open  to  the  man  who  knows  how 
to  handle  tools  and  how  to  build  models  from  the  base  to  the  last  gear. 
And  such  experience  can  only  be  gained  by  doing  the  work  with  one's 
own  hands.  The  time  spent  and  the  money  invested  in  the  necessary 
equipment  will  most  assuredly  pay  handsome  dividends,  and  rapidly  at 
that. 


type  and  its  size  may  vary  from  2  to  5 
inches.  It  will  be  found  that  the  2  inch 
size  is  excellent  for  light  work  while  the 
5  inch  variety  is  suitable  for  heavy  work. 
The  former  type  should    be    fitted  with 


Fig.  3.  This  Form  of  Drive  for  An  Experi- 
mental Work-shop  Makes  Use  of  a  3y2  H.P. 
Motorcycle  Engine.  It  Is  Geared  to  the  Line 
Shaft.  A  Rawhide  Or  Comprest  Paper 
Pinion  On  the  Engine  Will  Reduce  Any  Noise. 

since  several  factors  control  the  selection. 
First,  you  may  decide  to  start  with  a 
plain  lathe  of  good  quality,  so  constructed 
as  to  admit  of  conversion  to  screw-cutting 
at  a  later  date,  or  the  experimenter  may 
get  one  of  the  several  low  priced  screw- 
cutting  lathes  on  the  market. 

In  the  first  place  and  be- 
^^mm fore  purchasing  the  lathe, 
some  form  of  motive 
power  should  be  consid- 
ered so  that  undue  trouble 
may  be  eliminated  when 
the  necessary  equipment 
arrives.  The  author  at  first 
utilized  a  foot-operated 
lathe,  which  he  has  found 
to  be  entirely  satisfactory 
for  beginners  and  for 
handling  light  work. 
However,  he  has  found 
that  for  doing  actually 
good  work  on  a  lathe  some 
other  form  of  motive 
power  is  required  and  a 
small  gasoline  engine  of  V2 
H.P.  was  utilized  with 
great  success  in  driving  a 
9-inch  swing  screw-cutting 
2,  this  engine  is  shown 
coupled  to  a  countershaft  by  a  one-inch 
belt.  The  exhaust  pipe  is  led  out  thru 
the  window  and  the  whole  engine  is  sub- 
stantially secured  to  the  floor  as  noted. 


lathe.     In  Fig. 


January,  1918 


ELECTRICAL  EXPERIMENTER 


621 


Fig.  1. 


It  runs  very  quietly  in  this  manner  and  the 
consumption  of  fuel  is  very  small.  A  3]/2 
H.P.  motorcycle  gasoline  engine  was  also 
utilized  at  times  which  is  illustrated  in 
Fig.  3. 

This  was  an  old  discarded  engine  which 
was  overhauled  and  repaired  and  then 
utilized  for  power  purposes.  The  counter- 
shaft was  geared  to  the  engine  as  shown. 
It  is  advisable  that  the  prime  mover  be  in 
the  form  of  either  a  gasoline  engine  or 
electric  motor ;  the 
latter  is  more  advis- 
able since  it  is  very 
steady  and  noiseless 
and  further,  its  power 
can  easily  be  utilized 
for  driving  the  var- 
ious machines  by  in- 
dividual drive,  which 
will  be  treated  on  in  a 
later  article. 

Many  readers,  of 
course,  will  not  want 
to  secure  an  expens- 
ive lathe  and  for 
them  the  author  ad- 
vises a  treadle  oper- 
ated, small  speed 
lathe,  and  the  amateur 
today  can  obtain  a 
fairly  accurate  one 
for  about  $25.00.  The 
beginner  will  find  this 
type  of  lathe  very 
satisfactory,  and  for 
the  first  several 
months  he  should  be- 
come familiar 
in  handling  ordinary 
hand  turning  tools  f  or 
both  wood  and  metal. 
He  will  then  be  in 
a  better  position  to 

manage  his  more  complicated  lathe,  and 
he  will  never  regret  the  time  spent.  Later 
as  he  becomes  a  master  in  handling  the 
ordinary  lathe  with  hand  tools,  he  should 
then  proceed  to  purchase  a  more  expensive 
one,  and  it  is  an  excellent  plan  to  keep  the 
cheaper  one  for  wood  turning  and  metal 
spinning. 

When  procuring  a  lathe  the  following  ac- 
cessory tools  will  be  found  necessary :  A 
face-plate,  driver-plate,  two  centers,  and  a 
hand  tool  rest,  together  with  a  dozen  or  so 
%  inch  bolts  and  nuts  for  clamping  pur 
poses.  One  of  the  most  valuable  tools  for 
the  lathe  will  be  found  to  be  a  chuck,  which 
is  not  usually  furnished  with  the  lathe,  and 
this  device  is  very  essential,  especially 
when  metal  turning  and  drilling  is  to  be 
done.  A  self-centering  three  or  four-jaw 
chuck  can  be  purchased  for  a  nominal  sum 
and  it  will  repay  the  purchaser  in  a  short 
time. 

The  operation  and  the  handling  of  the 
lathe  will  be  fully  treated  in  the  second  in- 
stallment of  this  series.  Having  obtained 
the  lathe  the  following  list  of  tools  will  be 
found  very  useful  and  the  writer  suggests 
that  the  beginner  should  not  purchase  the 
complete  list  at  one  time,  but  gradually 
until  the  set  is  completed. 

The  first  thing  is  the  hammer  and  two 
are  sufficient,  one  about  4  oz.,  with  a  cross 
pene,  and  one  2  lbs.,  with  the  ball  pene. 
The  smaller  should  be  purchased  first  since 
much  work  can  be  done  with  it.  A  copper 
or  brass  as  well  as  a  raw-hide  hammer  is 
useful  for  finishing  up  work.  This  of 
course  is  optional  to  the  amateur. 

A  hack-saw  is  most  essential  and  it 
should  be  one  of  the  best  make ;  a  good 
one  can  be  secured  for  about  $1.50  and  it 
should  be  of  the  adjustable  type  in  order 
to  handle  blades  ranging  from  6  to  12 
inches.  The  tension  is  adjusted  by  the 
handle,  which  should  not  come  off  at  the 
critical  moment.  The  blades  should  usually 
have  fine  teeth    (23  per    inch),    but  for 


certain  work  such  as  in  cutting  cast  or 
wrought  iron  the  "star"  coarse  pitch  blade 
is  the  only  one  to  use.  Fine  pitch  blades 
with  many  teeth,  are  good  for  brass  and 
copper. 

The  next  important  tool  is  the  file  and  on 
its  quality  and  suitability  to  the  job  depends 
the  pleasure  of  one's  work.  They  should, 
therefore,  be  very  carefully  chosen.  The 
following  will  be  found  satisfactory  for  the 
start : 


A  Very  Efficient  Arrangement  of  the  Various  Machine  Tools,  Benches,  Shelves,  Etc 
Is  Shown  in  the  Plan  Herewith  of  the  Author's  Work-shop. 


(1)  For  heavy  work — One  12  inch  hand 
second-cut;  one  12-inch  half-round,  second- 
cut. 

These  will  be  found  invaluable  in  taking 
off  a  lot  of  metal,  as  a  good  sweep  can  be 
gotten  without  fear  of  bruising  one's 
knuckles. 

(2)  Medium  work — One  8  inch  hand, 
second-cut ;  one  8  inch  hand  smooth ;  one 
8  inch  half  round,  second  cut ;  one  8  inch 
half  round  smooth  ;  one  8  inch  three  square, 
second-cut;  one  8  inch  round,  second-cut 
and  one  8  inch  square,  second-cut. 

(3)  Very  light  work — One  or  two  sets 
of  six  4  inch  files  of  various  shapes  (flat, 
half  round,  round,  square  and  knife)  will 
be  found  most  satisfactory. 

A  metal  brush  for  cleaning  the  files  will 
be  required  and  it  should  be  seen  that  the 
wire  bristles  are  substantially  inlaid  so  that 
they  are  prevented  from  falling  out  when 
brisk  cleaning  is  done. 

Chisels — These  are  readily  made  in  the 
shop  as  one  can  select  one  in  whatever 
shape  or  size  he  desires.  The  general  type 
of  chisels  used  are  the  half-round,  diamond, 
cross  cut  and  flat. 

For  center  marking  holes  after  having 
been  laid  out  center  punches  are  used.  Two 
are  generally  sufficient.  4  inch  long,  one 
large  one,  about  3/16  inch  in  diameter  at 
the  end,  and  one  small  one  about  3/32  inch 
diameter. 

In  regards  to  drills  it  is  advisable  to  in- 
vest in  a  complete  set,  ranging  from  num- 
bers 1  to  60,  including  a  drill  stand.  It 
seldom  happens  that  the  amateur  employs 
drills  larger  than  a  */>  inch  and  for  this 
larger  group  the  following  will  be  found 
handy:— ^4,  5/16,  7/16  and  V2  inch.  If 
the  novice  is  unable  to  purchase  the  com- 
plete set,  he  can  at  first  simply  buy  the  drills 
which  will  suit  his  purpose  most  advantage- 
ously. 

The  problem  of  procuring  stock  and  dies 
for  the  amateur  work-shop  is  important  and 
for  this  reason  it  is  advisable  to  procure 


the  following:— 2-56;  4-36;  6-32;  8-32; 
10-32;  10-24;  12-24;  14-20;  V4-20.  All 
these  should  be  of  the  same  diameter,  so 
that  a  standard  holder  will  suit.  The 
inch  type  was  found  to  be  very  convenient. 
For  each  die  the  corresponding  tap  should 
be  obtained.  In  stock  and  die  sets,  taper 
and  plug  taps  are  usually  included.  An 
adjustable  tap  wrench  should  be  procured. 

Pliers  and  Nips  are  included  among  the 
hand  tools  and  for  the  former  the  parallel 
jaw  type  is  recom- 
mended. Toggle 
jointed  cutting  nippers 
are  advisable.  Gas 
pliers  will  be  found  at 
times  very  useful. 

Scales  and  Gages 
— Among  the  most 
important  tools  in  the 
shop  this  class  should 
be  of  the  finest  grade 
as  the  accuracy  of  the 
finished  work  will  de- 
pend a  great  deal 
upon  the  condition  of 
the  layout,  which  nat 
urally  is  reflected  to 
a  certain  degree  upon 
the  measuring  instru- 
ments. A  twelve-inch 
steel  scale  with  the 
following  di- 
vision will  be  useful : 
1/16,  1/32,  1/64 
inches.  There  are 
several  good  makes 
and  these  can  be 
procured  at  a  nominal 
price.  Inside  and 
outside  spring  calipers 
of  the  10-inch  variety 
are  very  handy ;  a 
tool-maker's  spring  di- 
viders and  combination  square  with  a  "V" 
centering  block  is  very  useful  and  the  ama- 
teur should  not  be  without  it.  A  pro- 
tractor attached  to  the  combination  square 
is  very  desirable  if  it  is  required  to  layout 
parts  at  various  angular  positions.  A  com- 
bination drill-thread  and  screw  gage  or  a 
drill  and  wire  gage  (a  good  one  is  the 
"Time  Saver"),  will  be  found  invaluable 
As  the  novice  becomes  more  experienced 
with  handling  measuring  tools  he  can  then 
invest  in  a  micrometer. 

The  various  other  hand  tools  which 
should  be  among  the  other  shop  equipment 
are  the  following: — ratchet,  screw  driver, 
wood  chisels  and  planes,  -hand  brace,  hand 
drill,  augers,  awls,  broaches,  reamers,  glass 
cutters,  wood  and  iron  clams,  hand  vises, 
center  gage  of  60  degrees,  countersinks  for 
wood  and  metal,  level,  and  metal  shears. 

Grinders  and  Polishers — These  should 
consist  of  two  heads,  one  for  erinding  work 
which  should  have  a  spindle  fitted  for 
two  grindstones,  one  a  corundum  wheel, 
while  the  other  side  has  a  carborundum 
wheel.  It  will  be  found  that  these  types  of 
wheel  will  be  most  suited  for  the  work 
which  the  amateur  will  meet  with.  The 
other,  or  polishing  head,  should  be  of  a 
lighter  construction  and  the  spindle  ends 
should  be  tapered  in  order  to  hold  polish- 
ing wheels.  In  some  of  these  polishing 
heads  an  extra  arbor  is  made  on  the  same 
shaft,  so  that  a  grinding  wheel  may  be  at- 
tached to  the  same  head.  For  the  one  who 
does  not  care  to  employ  two  heads,  the 
latter  is  therefore  advisable. 

The  driving  power  for  these  heads  can 
either  be  a  motor  or  foot-power.  If  the 
former  is  used,  a  l/&  H.P.  electric  motor 
will  be  sufficient  to  drive  it.  However,  if 
the  latter  form  of  power  is  utilized  an  old 
sewing  machine  foot  treadle  will  be  found 
very  useful  and  cheap  to  procure. 

Drill  Press — Altho  this  is  not  very  es- 
sential to  the  beginner,   (as  most  of  the 
(Continued  on  page  653) 


622 


THE  ELECTRICAL  EXPERIMENTER 


January,  1918 


A  New  Type  of  Chromic  Acid  Battery 

By  C.  A.  OLDROYD 


THE  great  advantage  of  all  chromic 
acid  batteries  is  their  high  E.  M.  F., 
namely  2  volts.  The  voltage  drops, 
however,  very  quickly  if  the  battery 
is  in  use  for  more  than  about  10 
minutes.    Various  designs  of  chromic  acid 


Electrical  Students  Are  Always  Partial  to 
the  "Chromic  Acid"  Battery,  Chiefly  Because 
Its  Potential  Is  High — viz.,  2  Volts.  The 
Author  Here  Describes  How  to  Build  a  Very 
Ingenious  and  Improved  Form  of  This  Useful 
Battery. 

batteries  have  been  brought  out,  at  different 
times,  to  overcome  the  inconstancy  and  the 
author  will  describe  in  detail  the  construc- 
tion of  a  modified  chromic  acid  battery  that 
will  supply  a  constant  current  as  long  as 
the  exciting  liquid  lasts. 

This  battery  can  be  built  very  easily  and 
cheaply  and  is  "just  the  thing"  for  spark 
coils,  small  motors,  electro-magnets,  etc. 
The  battery  described  here  consists  of  five 
cells ;  thus  giving  a  total  voltage  of  10  volts 
when  connected  in  series.  A  battery  with 
any  number  of  cells  can  however  easily  be 
built  from  the  directions  given. 

Each  cell  consists  of  a  carbon  plate  B, 
which  is  fixt  to  a  wooden  cover  A.  A  strip 
of  zinc  plate  C,  bent  as  shown,  encloses 
the  carbon  plate  B  and  between  B  and  C 
is  a  thin  layer  of  "glass  wool"  D ;  that  is 
spun  glass,  which  is  used  for  pocket  ac- 
cumulators and  many  other  purposes.  The 
zinc  plate  C  is  fastened  to  A  by  means  of 


screws  H  and  I.  The  latter  carries  a  bind- 
ing post  K,  while  H  is  fitted  with  a  nut  G. 

A  small  hole  is  drilled  on  the  center-line 
of  the  carbon  plate  B  and  two  holes  are 
drilled  from  the  sides  of  the  plate  to  meet 
the  hole  first  mentioned.  The  chromic  acid 
is  fed  into  the  vertical  hole  and  passes  thru 
the  two  holes  out  of  the  carbon  plate  B  into 
the  glass  wool  layer  D.  After  passing  to  the 
bottom  of  D  the  chromic  acid  leaves  the 
cell  thru  some  holes  in  the  zinc  plate  C. 

The  chromic  acid  is  fed  into  B  thru  a 
small  glass  tube  E,  which  is  connected  to  a 
container  M  by  means  of  rubber  tubing. 
The  end  of  E  is  drawn  to  a  fine  point,  so 
that  the  exciting  liquid  enters  the  hole  in 
B  in  a  very  fine  stream  or  only  as  drops, 
as  the  amount  required  is  very  small.  The 
tube  E  is  held  in  position  by  a  small  clip  F 
which  is  fastened  to  A  by  the  screw  H  and 
nut  G.  After  leaving  the  cell,  the  chromic 
acid  collects  at  the  bottom  of  the  battery 
jar,  as  shown  in  the  general  arrangement, 
and  is  finally  drained  away  thru  a  glass 
tube  S  into  a  storage  bottle  R. 

To  build  this  battery  procure  first  the 
carbon  plates  B  ;  as  all  the  other  dimensions 
are  fixt  by  the  size  of  B.  These  plates 
should  be  about  4"  wide  by  %y2"  long.  Drill 
a  hole  in  the  right  hand  top  corner  of  B  to 
suit  the  screw  W.  Then  drill  a  vertical  hole 
about  Y%"  dia.,on  the  center-line  of  the  plate 
V/z"  deep  and  from  each  side  a  similar  hole 
to  meet  the  vertical  hole.  The  carbon  plate 
B  is  now  finished  and  we  turn  to  the  zinc 
plate  C.  The  zinc  used  should  be  at  least 
1/16"  thick.  A  strip  of  the  length  required 
is  obtained  and  bent  as  shown  in  the  sketch. 
After  bending,  and  not  before,  amalgamate 
the  zinc  plate  C. 

We  can  now  assemble  one  cell.  A  slot  is 
cut  thru  the  cover  A  to  allow  the  carbon 
plate  B  to  pass  thru  and  B  is  fastened  by 
means  of  a  small  clip  Q  made  from  brass 
strip  about  Y\"  wide.  A  screw  W  is  now 
past  thru  Q  and  B  and  fitted  with  a  bind- 
ing post  K. 

We  now  fit  the  zinc  plate  C  to  the  carbon 
plate  B,  so  that  a  clearance  of  at  least  %" 
exists  all  round  between  the  carbon  plate 
and  the  zinc  plate.  This  clearance  is  now 
filled  with  glass  wool  and  the  easiest  way 
to  do  this  is  to  take  a  few  strands  of  glass 
wool  at  a  time  and  to  push  them  into  place 
by  means  of  a  steel  rule  or  a  knife. 

Now  comes  the  tube  E.  Take  a  short 
length  of  glass  tubing,  such  as  used  for 
chemical  experiments  and  heat  it  in  the 
middle  in  the  flame  of  a  Bunsen  burner  till 
it  becomes  quite  soft.  Then  remove  it  from 
the  flame  and  taking  one  end  of  the  tube 
into  each  hand,  pull  the  ends  apart  and  you 
will  find  that  the  tube  is  now  tapering  to  a 
fine  point  in  the  center.  Break  it  there  and 
grind  the  ends  down  till  the  opening  is  big 
enough  to  admit  an  ordinary  pin. 

The  clip  F,  for  the  tube  is  made  from 
thin  brass  plate  and  bent  as  shown.  A  hole 
is  drilled  thru  the  foot  of  F  to  allow  the 
screw  H  to  pass  thru.  Now  adjust  the  clip 
so  that  the  outlet  of  the  tube  is  directly  over 
the  hole  in  the  carbon  plate.  In  this  way 
all  the  cells  required,  in  our  case  five,  are 
completed  and  a  battery  jar  of  sufficient  size 
to  allow  at  least  1"  clearance  all  round  is 
procured  and  the  cover  A  fitted  to  it.  One 
of  the  rectangular  jars  used  for  storage  bat- 
teries will  do  very  well. 

Near  the  bottom,  a  hole  has  to  be  drilled 
thru  the  wall  of  the  jar  and  this  is  done  best 
by  a  glazier,  who  will  do  this  for  a  nominal 
sum.  A  glass  tube  S,  fitted  with  a  cock  U, 
is  fixt  into  the  jar  by  means  of  a  rubber 
stopper  T.  A  small  glass  tube  V  is  fixt  into 
the  cover  A,  after  having  been  bent  as 
shown.    A  container  M  of  about  54  of  a 


gallon  capacity  and  tubulated  near  the  bot- 
tom is  procured  and  fitted  with  a  cock  N. 
To  this  cock  a  branch-piece,  having  five 
branches,  is  joined  by  means  of  a  short 
length  of  rubber  tubing  and  each  branch  is 
connected  to  the  tube  E  of  each  cell.  The 
container  M  is  now  filled  with  chromic  acid 
and  the  cock  N  opened.  The  exciting  liquid 
travels  now  thru  the  branch  piece  and  tubing 
to  E,  thru  B  into  the  glass  wool  D  and  thru 
the  holes  at  the  bottom  of  the  zinc  plate  into 
the  jar  and  from  here  thru  S  into  a  bottle 
R.  Adjust  the  cock  N  in  such  a  way  that 
the  liquid  leaves  E  in  drops.  To  clean  the 
battery  after  use,  close  cocks  U  and  N  and 
connect  tube  V  to  the  watermain  ;  fill  the  jar 
with  water,  allow  to  stand  for  a  few  minutes 
and  drain  the  water  off  and  the  battery  will 
be  quite  clean. 


TO  KEEP  DRY  BATTERIES  FROM 
SHORT-CIRCUITING. 

When  a  number  of  dry  batteries  are 
placed  closely  together  in  a  damp  place,  the 
moisture  is  apt  to  soak  thru  the  paper 
covering,  making  an  electrical  connection 
between  the  zinc  casing.  To  avoid  this,  re- 
move the  cardboard  casings  and  wrap  a 
double  layer  of  friction  tape  (ordinary  bi- 
cycle repair  tape)  around  each  dry  cell 
near  the  top  and  near  the  bottom.  Also 
stretch  two  layers  of  the  tape  along  the 
shelf  about  an  inch  and  a  half  apart.  This 
will  insulate  the  cells  from  the  shelf  in 
case  the  latter  gets  wet  or  damp,  while  the 
tape  bands  will  keep  the  casings  from  com- 
ing into  contact  with  each  other  even  if 
set  close  together. 

Contributed  by  PETER  J.  M.  CLUTE. 


PRESERVING  CORKS  FROM  ACIDS 
AND  OTHER  ALKALIES 

I  had  considerable  trouble  with  the  corks 
which  I  used  in  the  bottles  in  my  labora- 
tory, from  being  corroded  by  acids  and 
other  alkalies,  so  I  used  the  following 
process  to  preserve  them  : — I  boiled  them 
for  some  time  in  paraffin ;  they  must  be 
kept  under  the  surface  of  the  hot  wax  and 
should  be  heated  and  allowed  to  cool,  re- 


Contoiner  M- 


Jar  dad  sfopperT 

~  dottle  R% 


Diagrammatic    Arrangement   of   5   Cell,  10 
Volt,  "Chromic  Acid"  Battery  Provided  with 
Means  for  Circulating  the  Electrolyte  and 
Cleaning  the  Container. 

peating  this  several  times,  so  as  to  get  all 
the  air  out  of  the  pores.  When  they  are 
treated  as  above  they  cut  easily  and  make 
very  close  joints. 

Contributed  by     EDWIN  MOTZEL. 


tlolefdrBP 

-  Carbon  plate  B  - 


Section  thru  one  ce/i 'ot 'bat 


■  Showing  the  way  of  fasten- 
ing carbon  plate  B  to 
cover  A'— 

thickness  of  carbon 

Holes  for  screws 


i  o  | 

n  oj  -c- 


•/'-I 
t 


Sending  fine ' 
Zinc  P/a/e  before  bendrng  ■ 


o 


ilJ 


-  Detail  of  clip  F 
and  gloss  fubel- 


© 


January,  1918 


ELECTRICAL  EXPERIMENTER 


623 


The  Ultra-Microscope  and  The  Underworld  of  Infinitesimal  Small 


"W 


'HAT  is  the  ultra-microscope 
and  what  has  it  bequeathed  to 
science?"  is  a  question  that  can 
be  answered  by  scarcely  one 
person  in  five  thousand.  If  you 
must  know  of  this  little  known  but  very  in- 
teresting and  vastly  important  scientific  in- 
strument, sharpen  your  imagination  and  let 
us  travel  into  the  underworld  of  infinitesimal 
small  and  roam  midst  molecules  and  atoms. 

When  salt  is  placed  in  water,  it  imme- 
diately disappears ;  that  is,  it  dissolves  or 
goes  into  solution.  Just  what  happens 
when  a  substance  goes  into  solution  fooled 
the  chemists  for  many 
years  and,  for  that 
matter,  has  them  puz- 
zled yet.  Some  say  it 
is  a  case  of  the  mere 
mixing  and  inter- 
mingling of  the  mole- 
cules, others  say  it  is  a 
case  of  chemical  com- 
bination, still  others  be- 
lieve it  to  be  an  aggre- 
gation of  the  former 
theories,  while  many 
uphold  the  theory  of 
electrolytic  dissociation 


By  FRANK  M.  GENTRY 

serve  to  bring  a  powerful  beam  of  light  to 
a  sharp  focus  within  the  object,  perpen- 
dicular to  the  line  of  vision.  There  are 
two  theories  regarding  its  operation. 

The  older  explanation,  based  upon  the 
law  of  sympathetic  vibrations,  assumes 
that  since  the  smallest  particle  discernible 
by  the  ordinary  method  is  about  0.0002  mm., 
or  about  1-127,000  of  an  inch,  which  is 
very  near  the  value  of  half  a  wave-length 
of  visible  light, — the  only  way  in  which 
a  particle  of  greater  minuteness  could  be 
made  visible  is  by  causing  it  to  emit  a 
light   of   its   own,   that   is,   become  self- 


light  not  exceeding  eight  wave-lengths,  the 
sub-microscopic  particles  become  visible,  on 
account  of  diffraction,  as  bright  objects 
upon  a  dark  field. 

But  whether  this  or  that  theory  is  cor- 
rect, is  of  no  concern  compared  with  what 
has  been  learned  by  the  use  of  the  ultra- 
microscope.  In  former  times  the  limit 
of  direct  observation  with  the  best  com- 
pound microscope  was  1-8333  of  a  milli- 
meter with  the  aid  of  a  special  immersion. 
Today  the  limit  of  visibility  of  the  ultra- 
microscope  is  directly  proportional  to  the 
specific  intensity  of  illumination.  With  the 
aid  of  intense  sunlight 
sub  -  microscopic  par- 
ticles of  0.0000039  mm., 
or  about  1-6,777,685  of 
an  inch  have  been  de- 
tected. The  magnifica- 
tion of  the  present  in- 
strument with  the  most 
powerful  beam  obtain- 
able is  approximately, 

r       i  12 


.1/600 -f-  1/6,777,685. 
=  127,602,778.8996 


or  ionization.  However, 

it  is  not  our  purpose  to  HH^HHHKHHHRHHBHR^^^^^ST                        "''                  I  times '•  where  1/600  is 

argue  the  points  of  the  /^-^^^^[fe.if-:^a?-ikS Y^'^^au.y'iu                 '  w          '!'..                                           I  equal  to  the  limit  of 

several  hypotheses  but  fj^^ajSFp^ HBMpWpSBBBi  f&m       §wj           HI                                    I  t,K'   ""aided   eye's  re- 

rather    to    study    the  igSqBHH                                                                                   -W  "                 I  so^vmS  power  in  inches, 

properties  of  solution.  ^j^SmW^jc,^  ,     »*^^'j2j?*'&i*  i     *     '       ■1x1  Hfl                  '•"                  I  The     hypothetical  di- 

If  we  pass  a  salt  so-  'if^^jf^K^P'r  '^^^&S^^!>  'i^X  '^ff'&BM  f/M '                                        I  ameters  of  the  larger 

lution  thru  filter  paper  flSSflftte   U^^T^^^M^n^'A  •  '    i  ,  Em  HM                                                 I  molecules  are:  hydro- 

we  obtain  no  residue.  W^'f^tP^S^&HJ^  I    V              Hr^H              X'','                     I  gen    1-10,000,000  mm. 

Again,  if  we  force  the  0sSSgS          V^HiV            WsBi  B9i   W^Wfwt                                 -  H  ethylalcohol  5-10,000,- 

liquid  thru  animal  mem  |H^|     W^^S^l^^^^^^'^^'^^^m  -'^mintM^        .%.*V-                     ;J  000    mm.,  chloroform 

brane    (which   has   no  WW  Jj^gMmM§^^BKSH^A-^BB""fB'    "                                '  8-10,000,000   mm,  and 

visible  pores;   the  salt  |M  ^i^lMlMB!g^SiS5gaej£B  I  starch  5-1,000,000  mm. 

is     not    yet    removed  H^LV      ImIS^^^^^'^B^'  •  "X '                                    I  T'lus                man  °" 

from  the  water.     Salt  Rf^S§lj                        vv '  *  *&3&  ^ '  ^fcr^'i     '                   '•  \       .                      I  tne    verge    of  distin- 

cannot     be     removed  WW&  r'^^jPsMtMS^yh^^^'^M- '"'  X '/■■-.  ■         'Xi  \  '  -  guishing  the  molecules 

from   solution  by  any  .$^§Kffli   WMwtB^&B3                                                           ' -;v    ■'       wSnH  and  atoms,  things  which 

process     of     filtration.  5^|#$^3«f$ftw  *\J8&.           v*** '    ^      »>*J    >  *                      *    J  scientists    dared  not 

Conversely,  if   a  little          W«SBfSP^;'-' ■'ip^P'W^*v!l:2-i,^fiii-Ll::l3:iL  ).XX  BRHS^M  dream,    and    in  fact, 

starch  be  dissolved  in      &<<#|i|KiB^f^  ' T  i^^SSSr^l  "the  large  molecules  of 

water,  it  presents  all  ^S^B^^^P-^X^'-^^'i--  mm  N  K^B  ind  of  cer- 
the  characteristics  of  a  ^^^^^^^^^^^B^B^^^^^^^^^^^^^^^^B^^^m^^^^^^^^^^^^^^^  tajn  fluorescent  sub- 
true  solution  until  the  The  Finest  of  Scientific"  Researches  Are  Made  Possible  Only  by  the  Application  of  the  stances  have  actually 
mixture  is  forced  thru  "Ultra-Microscope."  This  Remarkable  Yet  Relatively  Simple  Device  Consists  Essentially  been  seen!" 
animal  membrane,  when  °f  an  Especially  Constructed  Microscope  of  High  Magnifying  Power  and  Lenses  Which  Gaidukov  has  shown 
the  starch  is  recovered  Serve  t0  Br'"9  a  Powerful  Beam                   a  Sharp  Focus  Within  the  Object  Perpendic  that  the  protop,Lm,  the 


from  solution  as  the 
residue.  These  mixtures  were  called  by 
Prof.  Graham,  of  London,  hydrosols  or 
simply  colloidal  solutions. 

Prof.  Bredig  of  Heidelberg  prepared 
metals  in  the  colloidal  state  by  placing  two 
wires  of  the  desired  metal  in  a  shallow 
dish  of  water  and  forming  an  arc,  until  the 
solution  became  saturated,  by  passing  an 
electric  current  of  forty  volts  between  the 
electrodes.  Colloidal  platinum  is  a  deep 
brownish  black  color,  the  gold  is  a  beau- 
tiful ruby  and  the  silver  is  a  splendid  yel- 
low. 

The  beautiful  ruby  glass  prepared  at 
Jena  and  used  in  church  windows  and 
photographic  dark-rooms  is  produced  by 
the  introduction  of  minute  quantities  of 
gold  into  the  glass.  The  state  in  which 
the  gold  existed  was  long  a  subject  of 
bitter  controversy.  Was  the  color  due  to 
gold  in  solution  or  was  it  due  to  particles 
of  finely  divided  gold  suspended  in  the 
glass?  Was  it  a  case  of  true  solution  or 
of  colloidal  suspension?  It  was  this  ques- 
tion that  led  Siedentopf  and  Zsigmondy 
to  develop  the  ultra-microscope. 

The  ultra-microscope  consists  essentially 
of  an  especially  constructed  microscope  of 
high  magnifying  power  and  lenses  which 


ular  to  the  Line  of  Vision. 

luminous.  Accordingly,  a  great  amount  of 
energy  in  the  form  of  light  is  brought  to 
bear  by  means  of  powerful  lenses  upon  a 
comparatively  small  region  of  the  object 
under  examination.  This  great  concentra- 
tion of  vibrating  energy  causes  the  small 
particles  to  vibrate  in  unison  with  itself 
and  these  vibrations,  being  radiations  of 
visible  light,  cause  the  particles  to  become 
self-luminous  and  visible  thru  a  power- 
ful microscope.  This  beautiful  theory,  al- 
tho  romantic,  is  far  fetched  and  has  given 
way  to  a  later  explanation. 

The  second  theory,  based  upon  "Tyndall 
Phenomenon,"  is  the  one  generally  ac- 
cepted by  science  today.  It  makes  use  of 
the  principle  that  dust  suspended  in  the 
air,  while  invisible  in  the  open  sunlight,  is 
easily  seen  in  a  dark  room  under  the 
illumination  of  a  beam  of  light.  If  a 
beam  be  past  thru  a  beaker  of  water  it 
is  invisible,  but  if  the  same  beam  be  past 
thru  a  colloidal  solution  it  is  easily  traced 
by  a  diffused  streak.  Thus  when  the  sub- 
microscopic  particles  are  illuminated  by  the 
coaxial  method,  employed  in  ordinary 
microscopes,  they  are  invisible,  since  they 
are  encircled  by  the  light  waves  themselves. 
But  when  illuminated  by  a  thin  plane  of 


nucleus  of  a  cell,  the 
starch  grains,  and  the  chlorophyll  grains 
consist  of  a  thousand  sub-microscopic  par- 
ticles. So  far,  however,  not  a  single  sub- 
microscopic  organism  has  been  discovered 
which  has  not  led  to  a  disagreement  be- 
tween the  investigators  themselves.  The 
ultra-microscope  has  found  its  greatest  use 
in  determining  the  condition  of  solutions. 
It  has  been  shown  that  coloidal  solutions 
contain  minute  particles  of  varying  size; 
that  there  is  no  distinct  difference  between 
true  solutions  and  hydrosols ;  and  that  it  is 
possible  to  pass  gradually  from  one  to  the 
other.  The  particles  of  finely  divided  gold 
have  been  seen  suspended  in  ruby  giass. 
Since  the  size  of  the  beam  of  light  could 
easily  be  calculated,  the  particles  counted 
and,  knowing  the  specific  gravity  of  gold 
and  the  weight  introduced  into  the  glass,  it 
was  an  easy  matter  to  arrive  at  their  average 
size.  The  gold  dust  in  ruby  glass  averages 
1-6,000,000  of  an  inch  in  diameter. 

The  lack  of  exact  reproductive  power 
is  the  chief  defect  of  the  ultra-microscope. 
It  is  impossible,  however,  to  eradicate  this 
fault  at  the  present,  since  the  particles  are 
made  visible  by  the  interference  rings 
caused  by  diffraction. 

(Continued  on  page  653) 


624 


ELECTRICAL  EXPERIMENTER 


January,  1918 


This  department  will  award  the  following  monthly  prizes:    First  Prize,  $3.00;  Second  Prize,  $2.00;  Third  Prize,  $1.00. 

The  purpose  of  this  department  is  to  stimulate  experimenters  towards  accomplishing  new  things  with  old  apparatus  or  old  material, 
and  for  the  most  useful,  practical  and  original  idea  submitted  to  the  Editors  of  this  department,  a  monthly  series  of  prizes  will  be  awarded. 
For  the  best  idea  submitted  a  prize  of  $3.00  is  awarded  ;  for  the  second  best  idea  a  $2.00  prize,  and  for  the  third  best  prize  of  $1.00.  The  article 
need  not  be  very  elaborate,  and  rough  sketches  are  sufficient.  We  will  make  the  mechanical  drawings.  Use  only  one  side  of  sheet.  Hake 
sketches  on  separate  sheets. 


FIRST  PRIZE,  $3.00 


SECOND  PRIZE,  $2.00 


THIRD  PRIZE,  $1.00 


AN  ELECTRIC  IRON  VULCANIZER. 

All  Bugs  and  Buglets  who  own  flivvers, 
etc.,  may  find  this  wrinkle  of  some  value  in 
saving  a  small  part  of  the  vulcanizer's 
bill  which  is  always  large,  by  follow- 
ing these  instructions  closely.  First 
clean  the  tube  around  the  puncture  thoroly 
with  gasoline,  now  apply  some  quick  cure 
cement  by  smearing  it  on  with  your  finger 
(don't  lick  your  finger),  covering  a  space 
about  the  size  of  a  quarter,  next  cut  out  a 
piece  of  raw  rubber  or  gum  about  the  size 
of  a  dime  and  cover  the  hole,  but  be  sure 
that  the  cement  has  dried  perfectly  before 
doing  so ;  now  all  is  ready  for  the  cooking. 

Hunt  up  an  old  electric  iron  and  clean  off 
the  smooth  surface  so  there  is  no  rust  or 
other  dirt  and  heat  it  to  about  the  tempera- 


g==JI 


If  You  Possess  or  Can  Borrow  an  Electric 
Sad  Iron,  It  Then  Becomes  a  Simple  Matter 
to  Vulcanize  Tires  in  a  Few  Moments. 


ture  that  is  used  for  ironing  and  clamp  the 
tube  down  firmly,  then  let  it  cook  for  five 
minutes.  When  you  take  it  off  you  will 
have  a  patch  that  will  not  readily  come  off. 

And  as  for  the  cement  and  gum  you  can 
obtain  that  at  any  rubber  supply  house  or 
vulcanizer. 

Contributed  by 

THEODORE  F.  LITER. 


APPLICATION  OF  RADIO-ACTIVE 
SALTS  TO  BATTERIES. 

^  A  recent  French  patent,  due  to  M.  H.  G. 
C.  Thofehern,  is  concerned  with  the  use  of 
radio-active  material  for  the  purpose  of  fa- 
cilitating the  chemical  action  taking  place  in 
accumulators.  For  this  purpose  radium 
barium  sulfate  is  suggested.  The  material 
is  insoluble  in  the  electrolyte,  and  does  not 
appear  to  enter  into  chemical  combination 
with  the  lead  oxid  or  the  metallic  lead  of 
the  plates.  Its  presence,  however,  is  assumed 
to  render  the  chemical  action  more  complete 
during  charge  and  discharge ;  otherwise  the 
process  is  normal.  About  0-2  microgrammes 
of  radium  per  pound  of  lead  oxid  is  used, 
the  radium  compound  being  merely  incor- 
porated in  the  oxid  used  on  the  plate  grid. 


SIMPLE  RELAY  MADE  FROM 
BUZZER. 

The  relay  here  shown  is  made  from  an 
old  bell  or  buzzer  and  is  fairly  sensitive. 
Twist  the  adjustable  contact  screw  around 


Toseccct 


Prim  ccf.-- 


® 


The  Simplest  Relay  Is  Made  by  Twisting  the 
Contact  Screw  Post  on  a  Bell  or  Buzzer  to 
the  Position  Shown,  Also  Bending  the  Arma- 
ture Spring  a  Trifle. 

as  at  (A)  and  bend  the  circuit-breaking 
contact  spring  as  shown. 

A  wire  from  (A)  is  run  to  a  binding  post 
and  another  from  the  armature  to  a  bind- 
ing post. 

Contributed  by 

EDWARD  M.  WYLAND. 


ADJUSTING  AUTO  COILS. 

To  adjust  the  spark  coils  on  an  automo- 
bile, without  leaving  the  car  and  turning 
each  cylinder  circuit  to  contact  on  the 
commutator,  a  wire  may  be  grounded  on 
the  steering  wheel  shaft,  the  switch  closed 


Easy    Method    For   Testing   and  Adlusting 
Auto  Ignition  Coils. 

and  the  top  of  each  vibrator  screw  touched 
with  the  end  of  the  wire  until  the  proper 
buzz  is  heard. 
Contributed  by  JOHN  SCHMITZEIS. 

TEST  PAPERS 

The  following  are  some  test  papers  which 
I  think  the  experimenter  will  find  useful. 


HOME-MADE    BATTERY  CHARG- 
ING   CUT-OUT    MADE  FROM 
POLARIZED  BELLRINGER. 

Having  some  storage  batteries  I  wanted 
charged  and  being  unable  to  watch  them 
all  the  time,  I  thought  of  the  plan  shown  in 
the  drawing  and  it  has  worked  successfully 
so  far.  The  operation  is  as  follows :  When 
the  dynamo  generates  the  proper  cur- 
rent, the  500  ohm  magnet  coils  (polarized 
telephone  ringer)  are  energized,  which 
closes  the  contact  attached  to  the  clapper 
rod.  The  storage  battery  begins  charging 
now  and  continues  to  charge  until  the 
dynamo  stops  or  something  happens,  where- 
by the  contact  is  broken;  thus  shutting  off 
the  battery  "juice"  from  the  line. 

Contributed  by  ERNEST  JOHNSON. 


Armature 


m 


o/dte/eg. 
sounder'' 


C/apper 
rod 

500  Ohm 
magnet  coils 


Storage  f 


"-  /ow  vo/fage  dgnamo 


EE 


A   Good   Automatic   Charging   Cut-Out  For 
Batteries  Is  Readily  Made  From  a  500  Ohm 
Polarized  Ringer  As  Shown. 


Use  the  best  filter  paper  cut  in  strips,  im- 
merse in  the  solution,  and  dry  in  an  at- 
mosphere free  from  ammonia  or  hydrogen 
sulfid. 

Ferrous  sulfat  FeSOt.  Dip  in  solution 
and  dry;  test  for  hydrocyanic  acid  cyanides. 
Gives  a  blue  color. 

Iris  paper.  Make  extract  of  the  roots  of 
the  Blue  Iris  (Iris  versicolor).  Dip  paper 
in  solution.  Dry. 

Neutral  solutions  give  blue ;  acids  red ; 
alkali  green. 

Lead  Acetat.  Dip  .in  solution  and  dry. 
Sulfides  give  black. 

Pole  test  paper.  Dip  in  a  solution  of 
phenolphthalein  and  dry.  Then  in  a  solu- 
tion of  sodium  sulfate. 

Negative  pole  gives  red  spot. 

Potassium  bichromat.  Same  as  other 
papers.  Lead  salts  give  yellow.  Silver  salts 
red. 

Silver  nitrat.  Keep  in  a  dark  bottle.  Lead 
gives  black;  Arsenic  yellow;  Chromates 
red. 

Dry  in  air  free  from  H2S. 
Potassium  ferrocyanid.    Ferric  salts  give 
blue.    Cupric  salts  red. 

Contributed  by  F.  G.  HOPPER. 


January,  1918 


ELECTRICAL  EXPERIMENTER 


625 


Wrf- inkles 


rrt  u  1  sts. 


EDITED  BY  S.GERNSBACK 


Under  this  heading  we  publish  every  month 
useful  information  In  Mechanics,  Electricity 
Mid  Chemistry.  We  shall  be  pleased,  of 
course,  to  have  our  readers  send  us  any 
recipes,  formulas,  wrinkles,  new  ideas,  etc., 
useful  to  the  experimenter,  which  will  be 
duly  paid  for,  upon  publication,  if  acceptable. 


HOW  TO  MAKE  A  CHEMICAL 
GARDEN. 

Place  a  quantity  of  sand  in  a  wide 
mouthed  bottle  or  fish  aquarium  to  a 
depth  of  about  three  inches.  Slightly  im- 
bed a  few  pieces  of  copper  sulfate,  alumi- 
num sulfate,  iron  sulfate,  chrome  alum, 
lead  acetate,  calcium  chlorid,  magnesium 
and  manganese  sulfates,  in  the  layer  of 
sand  (all  these  chemicals  can  be  purchased 
at  any  drug  store).  Make  a  solution  of 
water  glass  (sodium  silicate)  one  part 
water  glass  and  three  parts  water,  pour 
this  solution  carefully  over  the  sand  and 
chemicals.  In  about  a  week  a  dense  growth 
of  the  silicates  of  the  various  bases  will  be 
seen,  in  various  colors  and  fantastic  shapes. 
Now  displace  the  solution  of  the  water 
glass  with  clear  water,  by  conveying  a 
small  stream  of  water  thru  a  small  rubber 
tube  into  the  vessel,  which  will  gradually 
displace  the  solution  of  water  glass.  Care 
must  be  taken  not  to  disarrange  or  break 
down  the  growth  with  the  stream  of  water. 
Other  sulfate  such  as  chromium,  nickel, 
cobalt,  etc.,  may  also  be  used.  When  suc- 
cessful this  produces  a  very  beautiful 
scene 

Contributed  by  ALBERT  W.  PUTLAND. 


HOW  TO  CUT  GLASS  TUBES. 

A  good  way  to  cut  glass  tubes  with  the 
ordinary  glass  cutter  is  to  bore  a  hole  in 
your  work  bench  and  fit  a  glass  cutter  in 
it'with  the  handle  down,  so  that  the  wheel  is 
about  one  eighth  of  an  inch  above  the  level 
of  the  bench.  Lay  the  tube  to  be  cut  against 


G/ass  tube 


L 


Wor/r  ■ 
Bene/? 


Coffer 


© 


Cutting  Glass  Tubes  Is  Always  a  Problem  to 
the  Amateur.    Here's  a  Simple  Method  Using 
an  Ordinary  Glass  Cutter. 

the  cutting  wheel  of  the  glass  cutter  and 
turn  with  the  hand  as  shown  in  the  illus- 
tration. This  scores  the  glass  so  that  the 
tube  may  be  easily  broken  with  the  hands. 
Contributed  by  LAVERNE  WISE. 


SIMPLE  TESTS  FOR  LEAVENING 
CAPACITY  AND  PURITY  OF 
BAKING  POWDERS. 

To  ascertain  the  leavening  capacity,  place 
as  many  glass  tumblers  in  a  row  as  you 
have  baking  powders  to  test.  Measure  half 
a  teaspoonful  of  each  baking  powder  into 
a  tumbler  by  itself,  and  fill  two-thirds  full 
of  clear,  cold  water.  Set  the  tumblers  be- 
tween- yourself  and  the  light,  observing 
which  throws  off  the  larger  amount  of  tiny 
gas  bubbles.  The  one  that  liberates  these  in 
the  greatest  abundance,  possesses  the  high- 
est leavening  power,  as  these  tiny  globules 
developing  in  the  dough,  cause  it  to  rise 
and  become  light. 

To  test  for  purity  place  as  many  teacups 
in  a  row  as  you  have  baking  powders  to 
test.  Deal  a  teaspoonful  of  each  into  its 
separate  cup.  Pour  a  very  little  boiling 
water  from  the  teakettle  into  each  and  in 
about  two  minutes  fill  with  boiling  water. 
After  they  have  stood  half  an  hour  to  cool, 
pour  each  into  a  separate  glass  tumbler  and 
set  aside  to  rest.  The  baking  powders  that 
are  pure  and  free  from  stuffing  will  be 
completely  dissolved  and  the  water  will  be 
as  clear  as  crystal.  The  cloudiness  and 
precipitate  at  the  bottom  of  the  impure  ones 
will  tell  the  amount  of  adulteration  and  of 
impurity.  The  tumbler  with  its  solution  as 
clear  as  crystal  contains  pure  cream  of  tar- 
tar and  no  adulterants.  The  tumblers  con- 
taining turbid  solutions  and  yielding  small 
precipitates  contain  little  cream  of  tartar 
but  phosfates  of  calcium  and  stuffing.  The 
tumblers  containing  very  turbid  solutions 
and  yielding  heavy  precipitates  contain  no 
cream  of  tartar,  whatsoever,  but  plenty  of 
alum  and  stuffing. 

Baking  powders  containing  pure  cream 
of  tartar  are  recognized  to  be  the  best  by 
experts  while  those  containing  phosfates  and 
alum  are  regarded  to  be  unwholesome  and 
detrimental  to  our  stomachs. 

Contributed  by 

FRANK  BECHTOLD,  JR. 


BLUE  PRINTING 

To  obtain  white  lines  on  a  blue  ground : 
Solution  No.  1. 

Ammonia  Citrat  of  Iron  1  oz. 

Water  4oz. 

Solution  No.  2. 

Ferricyanid  of  Potassium  1  oz. 

Water  ••  4oz. 

Coating  Solution  : 

Directions — Mix  equal  portions  of  solu- 
tion No.  1  and  No.  2.  Coat  the  paper  with 
a  camels  hair  brush  (like  painting)  or  rub 
on  solution  with  a  tuft  of  absorbent  cot- 
ton. Any  good  bond  paper  will  do,  a  mat 
surface  writing  paper  is  _  good.  Paper 
should  be  dried  after  coating  in  a  dark 
room,  develop  in  water. 

Contributed  by 

JOHN  BLACKHURST. 


TIN  PLATING 


To  tin-plate  a  small  article  like  a  copper 
penny  or  a  copper  statue  proceed  this  way. 
Put  a  half  teaspoon  of  tartaric  acid  in  a 
bright  and  shiny  tin  cup.  Put  the  article 
in  the  cup  and  fill  the  latter  about  three- 
fourths  full  of  water  and  set  on  stove  to 
boil.  Boil  till  water  is  nearly  all  driven  off. 
The  article  is  now  tin-plated  and  a  little 
polishing  will  make  it  shine  as  bright  as  a 
new  dime.  In  this  experiment  the  tartaric 
acid  dissolves  the  tin  and  plates  the  object 
which  is  in  the  cup. 

The  object  to  be  plated  must  be  clean 
and  free  from  dirt  or  it  will  plate  unevenly. 
To  clean  the  article  dip  in  weak  sulfuric 
acid  and  dry. 

Contributed  by 

MANSELL  SARGENT. 


IMPROVED    BICHROMAT  DARK- 
ROOM   LAMP    FOR  PHOTOG- 
RAPHERS. 

Some  time  ago  you  publisht  a  description 
of  the  above  type  lamp  which  shows  a  bat- 
tery and  rheostat  connected  in  the  external 
circuit  to  light  the  lamp  within  the  red 
solution  of  Bichromat  of  Potash. 

I  desire  to  describe  an  improvement  which 
is  more  convenient,  less  expensive  and  yet 
one  which  will  give  good  service.  Place  a 
carbon  and  zinc  within  the  bottle  and  con- 
nect them  to  the  lamp.  Put  the  following 
solution  in  the  bottle;  dissolve  24  ounces 
of  Bichromat  of  Potash  in  1  gallon  of  water 


G/ass  /esf  fade 


Improved  Idea  for  Making  a  Photographer's 
Dark  Room   Lamp  Which   Incorporates  the 
Battery,  Lamp  and  Red  Coloring  Solution  All 
in  One  Jar. 

and  then  slowly  add  72  ounces  of  Sulfuric 
Acid.  If  only  one-quarter  of  solution  is 
desired  use  one-quarter  of  the  above 
amounts.  For  the  lamp  procure  one  of  the 
lamps  now  used  in  operation  with  a  one 
or  two  cell  dry  battery  flash-light;  they  can 
be  bought  in  the  5  and  10  cent  stores  for  a 
dime.  This  battery  will  give  about  2^  volts 
and  can  be  used  for  constant  service.  The 
zinc  will  last  much  longer  if  first  dipt  in 
sulfuric  acid  solution  and  rubbed  quickly 
with  mercury.  To  open  the  lamp  circuit  re- 
move the  zinc  rod. 

Contributed  by  THOS.  APPLEBY. 


BROWN  OR  SEPIA  TONES  ON 
BROMID  AND  GASLIGHT 
PAPER 

Photographic  Printing  Paper: — 
Solution  No.  1. — Bleaching  Solution. 

Bromid  of  Ammonia  1  oz. 

Water  16  oz. 

Solution  No.  2. 

Ferricyanid  of  Potassium  ...1  oz. 

Water  12  oz. 

Solution  No.  3. — Browning  Solution. 

Sulfid  of  Soda   1  oz. 

Water  12  oz. 

(Do  not  confuse  Sulfid  with  Sulfite) 

Directions  for  Brown  or  Sepia  Tones  on 
Bromid  or  Gaslight  Photographic  paper  :— 
Take  a  print  from  the  negative  in  the  usual 
manner,  develop  and  fix ;  when  thoroly 
washed,  place  in  developing  tray,  and 
develop  till  image  becomes  faint  in : — 

Solution  No.  1  4oz. 

Solution  No.  2  4oz. 

Mix  together  in  container  bottle ;  label 
bleaching  fluid. 

Wash  once  only,  (too  much  washing  will 
spoil  the  work)  ;  the  solutions  will  keep 
indefinitely.  After  washing  the  print,  fill 
the  developing  tray  with  water,  placing  the 
print  in  the  tray  with  the  water,  and  add 
a  teaspoonful  of  (browning  solution). 

Solution  No.  3 — Develop  till  the  desired 
tone  is  acquired,  and  wash  well  in  running 
water. 

Solution  will  not  keep. 

Contributed  by 

JOHN  BLACKHURST. 


626 


ELECTRICAL  EXPERIMENTER 


January,  1918 


Experimental  Chemistry 


By  ALBERT  W.  WILSDON 
Twentieth  Lesson 


VALENCE. 

DOUBTLESS  many  readers  of  pre- 
vious installments  have  wondered 
how  to  determine,  how  to  write 
symbols  for  certain  compounds  in 
order  to  write  an  equation.  For 
instance,  how  are  we  to  know  whether  to 
write  the  symbol  of  a  given  compound  with 
1,  2,  3,  or  4  atoms  of  either  of  its  elements? 


Fig.  1.  Illustrating  Graphically  the  Tetra- 
valent    Element    Carbon    (C)    in  Methane. 


For  example,  shall  we  write  Sodium 
Chlorid  NaCl,  Na2Cl,  NaCL,  NaCU,  or 
NalCh,  etc.?  It  is  evident  that  one  of  these 
is  correct ;  the  others  must  be  wrong. 

The  object  of  this  installent  is  to 
ascertain  in  what  way  the  atoms  of  the 
elements  combine.  In  the  last  paper  we 
took  up  the  study  of  certain  laws  of 
chemistry  with  respect  to  the  balancing  of 
equations,  and  the  ration  with  which  ele- 
ments combine. 

SYMBOLS  OF  ELEMENTS  AND 
COMPOUNDS. 

When  expressing  the  composition  of 
various  chemical  substances  which  are  made 


r 

H 

H 

6 

O  ■ 

up  of  various  elements,  as  a  matter  of 
simplicity,  an  abbreviated  form  of  chemical 
language  is  employed. 

An  atom  of  copper  is  the  sfnallest 
particle  of  copper  that  is  found  in  any 
compound.  The  symbol  for  an  atom  of 
copper  is  Cu ;  that  of  an  atom  of  Oxygen, 
O ;  of  Sulfur,  S,  etc.,  etc.  For  the  symbols 
of  the  other  elements,  together  with  their 
atomic  weights  reference  to  the  table  given 
in  the  last  lesson  should  be  made.  Every 
element  possesses  a  symbol  which  stands 
for  its  atom.  If  more  than  one  atom  of  an 
element  is  indicated,  a  co-efficient  or  sub- 
exponent  is  used  as  2C1  or  CU,  which  means 
two  atoms  of  Chlorin. 

A  symbol  is  usually  the  initial  letter  or 
letters  of  the  Latin  name  of  the  element, 
which  does  not  in  every  case  correspond 
to  the  English  name.  In  some  cases  several 
elements  possess  the  same  initial  letter.  It 
is  then  the  custom  to  assign  the  single  let- 
ter to  the  most  important,  abundant  or 
earliest  discovered  member  of  the  group 
and  to  the  others  another  letter  contained 
in  the  name  of  the  element.  Thus,  ten 
names  of  elements  begin  with  C.  This 
symbol  was  selected  for  Carbon  as  the  most 
important  then  Ca  for  Calcium ;  Cd  for 
Cadmium  ;  Ce  for  Cerium ;  CI  for  Chlorin  ; 
Co  for  Cobalt,  etc. 

A  few  names  in  which  the  Latin  names 
differ  from  the  English,  are :  Fe  from  Fer- 
rum  (Iron)  ;  Sb  from  Stibium  (Anti- 
mony) ;  Cu  from  Cuprum  (Copper)  ;  Pb 
from  Plumbum  (Lead)  ;  Hg  from  Hydrar- 
gyrum (Mercury)  ;  Ag  from  Argentum 
(Silver)  ;  Na  from  Natrium  (Sodium)  ;  K 
from  Kalium  (Potassium)  ;  Sn  from  Stan- 
nura  (Tin)  ;  Au  from  Aurum  (Gold). 

Symbols  possess  a  quantitative  signifi- 
cance.  Each  one  represents  one  atom  of 
the  element  in  question,  this  being  the 
smallest  quantity  of  an  element  which  is 
present  in  the  molecule  of  its  compounds. 
Thus  Na  does  not  represent  any  indefinite 
quantity  of  Sodium,  nor  does  CI  represent 
any  amount  of  Chlorin,  but  each  represent  a 
definite  mass,  one  part  by  weight.  Thus  we 
see  that  the  symbol  not  only  is  an  abbrevia- 
tion of  the  name  of  the  substance,  but  also 
signifies  a  definite  amount  or  quantity  of 
the  Substance.  Na  means  one  atom  of 
Sodium,  also  23  parts  by  weight  of  Sodium. 

The  formula  of  a  molecule  is  formed  by 
grouping  together  the  symbols  of  the  atoms 
composing  it.  The  molecule  of  Hydro- 
chloric acid  is  found  to  consist  of  one  atom 
of  hydrogen  and  one  atom  of  chlorin,  ex- 
pression of  which  formula  is  : — 


H  +  CI 
Symbols  of  elements 


HC1 

Formula  of  compound 


Fig.  4.  The  Upper  Line  Illustrates  Graphic- 
ally a  Trivalent  Or  Triad  Element — Nitrogen 
(N)  in  the  Ammonia  Radical  (NHa);  Lower 
Line  Shows  Why  Ammonia  Could  Not  Be 
Written  NH>, 


This  formula  (HC1)  means: 

1.  One  molecule  of  hydrochloric  acid. 

2.  One  molecule  of  hydrochloric  acid 
containing  one  atom  of  hydrogen  and  one 
atom  of  chlorin. 

3.  One  molecule  of  hydrochloric  acid 
composed  of  1  part  by  weight  of  hydrogen, 
and  35.46  parts  by  weight  of  chlorin. 

4.  One  part  of  hydrogen  plus  35.46  parts 
of  chlorin  equal  36.46  parts  of  hydrochloric 
acid  by  weight. 

EQUATIONS: 

What  is  an  Equation?  What  is  a  Re- 
action? These  are  questions  which  have 
probably  come  up  to  numerous  readers. 

When  we  speak  of  a  Reaction,  it  is  meant 
for  some  definite  chemical  action  which 
takes  place  between  two  or  more  molecules, 
but  the  term  is  also  used  for  an  Equation. 


An  equation  stands  for  a  reaction.  It  rep- 
resents a  chemical  experiment. 

As  stated  before,  symbols  and  equations, 
together  with  certain  algebraic  signs  are 
the  shorthand  of  chemistry.  An  equation 
gives  the  substances  that  are  put  together 
in  an   experiment,   and  those  which  are 


Fig.  2.    The  Several  Ways  of  Representing 
"Valence."    The  Usual  Method  Involves  the 
Use  of  Blocks  With  1,  2  Or  More  Hooks  Ar- 
ranged As  Shown  in  the  Upper  View. 


obtained  as  a  result,  together  with  the  right 
ratio  of  those  used  and  of  the  ones 
obtained. 

FACTORS  AND  PRODUCTS : 

The  substances  put  together  for  a  given 
experiment  are  called  "factors,"  and  those 
obtained  the  "products." 

If  one  contemplates  advancing  himself  in 
chemical  knowledge,  it  is  imperative  that 
he  know  how  to  write  equations.  There 
are  three  essentials  to  be  mastered  by  the 
student.  (1)  to  know  the  factors  and  their 
symbols;  (2)  to  know  the  products  and 
their  symbols ;  (3)  to  balance  the  equation. 

(Note: — A  list  of  the  elements,  together 
with  their  symbols  with  atomic  weights  was 
given  in  the  last  lesson,  page  559). 

(1)  FACTORS :— The  first  thing  to  do 
is  to  write  down  the  symbols  of  the  sub- 
stances which  were  put  together  to  obtain 
the  result.  Thus,  in  making  Iron  sulfid, 
we  must  first  write  down  the  symbols  for 
the  substances  to  be  put  together,  namely, 
Fe  and  S.  These  two  substances  compose 
the  first  half  of  the  equation  and  should  be 
written :  Fe  +  S  =  . 

The  symbols  of  the  factors  are  always 
written  on  the  left  hand  of  an  equation, 


Fig.  3.  Upper  Line  Shows  a  Bivalent  Or 
Dyad  Element — Oxygen  (O)  in  Water  HaO. 
Lower  Line  Shows  Why  the  Symbol  for 
Water  Could  Not  Be  HO.  There  Would  Be  a 
"Free"  Hook  Or  Bond. 

and  the  number  of  factors  are  variable. 
Sometimes  we  use  only  one  factor,  i.e., 
breaking  up  Red  Oxid  of  mercury  (HgO)  ; 
or  two  or  more  factors,  in  an  experi- 
ment. 

(In  the  preparation  of  hydrogen,  water 
was  employed  merely  as  a  solvent  of  the 
{Continued  on  page  636) 


January,   1918  ELECTRICAL   EXPERIMENTER  62  7 


Our  Amateur  Laboratory  Contest  is  open  to  all  readers,  whether  subscribers  or  not.  The  photos  are  judged  for  best  arrangement  and  efficiency 
of  the  apparatus.  To  increase  the  interest  of  this  department  we  make  it  a  rule  not  to  publish  photos  of  apparatus  unaccompanied  by  that  of  the  owner.  Dark 
photos  preferred  to  light  toned  ones.  We  pay  each  month  $3.00  prize  for  the  best  photo.  Make  your  description  brief  and  use  only  one  side  of  the  sheet 
Address  the  Editor,    With  the  Amateurs"  Dept. 


Send  a  Photo  of  Your  "Electrical  Lab." 

"Radio-bugs,"  just  keep  up  the  good  work!  Send  us  a  photograph  of  your  "Electrical  Laboratory"  now  so  that  we 
can  judge  them  for  the  February  prize  contest.  You  might  as  well  take  a  chance  on  winning  the  monthly  prize  as  well  as 
anyone  else.  Talking  about  prizes,  we  want  to  speak  particularly  about  this  month's  prize  winner — Mr.  Edward  G.  Raser,  of 
Trenton,  N.  J.  Now  Mr.  Raser  has  a  genuine  "Electrical  Lab."  No  mistake — "Bugs."  Among  other  things  he  owns  a  Wheat- 
stone  bridge,  a  Potentiometer,  two  D.  C.  Galvanometers,  Kelvin  bridge  for  measuring  extremely  low  resistances,  Millivolt- 
meter,  a  Standard  Cell,  a  Pyrovolter,  etc.  He  also  has  two  resistance  furnaces  which  lie  on  the  floor  at  the  right  and  can- 
not be  seen  in  the  picture.  He  uses  220  volts  and  steps  it  down  to  50  volts  by  means  of  a  large  transformer  and  can  melt 
brass,  copper,  tin  and  lead  with  the  aforementioned  apparatus.  An  electric  arc  run  from  the  same  source  of  supply  is  used 
for  welding  purposes  and  obtaining  high  temperatures.  Address  your  "Electrical  Lab."  photos  to  Editor  "With  the  Ama- 
teurs Prize  Contest." 


A   GROUP   OF    REPRESENTATIVE    AMERICAN    AMATEUR  LABORATORIES, 
lectrical  Laboratories  of,  1— Edward  G.  Raser,  Trenton,  N.  J.;  2— Richard  S.  Owen,  Pittsburgh,  Pa.;  3— J.  F.  Freeman,  Tucson,  Ariz.;  4— 
aryey  McCoy  FitzSimmons,  Mansfield,  Ohio;  5— Harold  Martin,  Pasadena,  Calif.  Radio  Stations  of,  6— Earl  S.  Nelson,  Cleveland,  Ohio; 
-Ted  Lively,  Morrison,  III.;  8— Sedric  R.  Brown,  Oceanside,  Calif.;  9— D.  E.  Barthel,  Elkader,  la.;  10— Theodore  Gathmann,  New  York  City; 

11— Fonda  McCook,  Sumner,  la.;  12— C:  H.  Langford,  London,  Ont.,  Canada. 


628 


ELECTRICAL  EXPERIMENTER 


January,  1918 


RTEST  PATENTS 


Bicycle  Lamp 

(No.  1,244,262;  issued  to  H.  R.  Van 
Deventer. ) 
Those  who  ride  bicycles  will  be 
interested  in  this  ingenious  dynamo 
headlight  which  is  arranged  to  be 
driven  by  frictional  contact  between 
its  driving  pulley  and  the  tire  on 


the  bicycle  wheel.  The  details  are 
very  simple,  there  being  provided  a 
permanent  -  magnet  type  dynamo, 
which  can  be  swung  into  contact 
with  or  away  from  the  bicycle  tire. 
The  dynamo  shaft  carries  on  its 
upper  end  a  suitable  receptacle  for 
the  low  voltage  lamp,  and  the  latter 
therefore  rotates  with  the  armature, 
giving  a  very  efficient  illumination. 


(No. 


Gas  and  Smoke  Alarm 

1,242,575;  issued  to  Silvestro 
Milano.) 

Many  lives  have  been  lost  annual- 
ly from  smoke  and  gas  escaping  in 
dwellings.  The  present  device  is  of 
great  interest  therefore,  in  that  it 
will  give  an  alarm  from  gas,  smoke 


or  fire.  The  device  consists  of  a 
circuit  maker  and  breaker  embody- 
ing a  thermostatic  spring  responsive 
to  abnormal  temperature  changes, 
together  with  means  sensitive  to  the 
presence  of  illuminating  gases,  so 
that  when  subjected  thereto  said 
means  will  generate  heat,  as  is  the 
case  by  using  for  the  purpose  spongy 
platinum.  If  gas  happens  to  escape 
mt«  the  room,  this  element  will  be- 
come heated  to  a  glowing  condition, 
whereby  it  will  influence  the  thermo- 
static spring,  and  thus  close  the 
alarm  circuit,  which  may  be  either 
audible  or  visual. 


r-Kj      ,  Telephone  Amplifier 

(No.  1,243,755-  issued  to  F.  C  C 
Naeser  and  N.  A.  J.  Lilliendahl- 

Petersen.) 
An  auxiliary  apparatus  for  use  in 


connection  with  regular  telephone 
equipment,  providing  amplifying 
means  so  that  one  or  more  persons 
may  readily  hear  _  the  telephone 
speech  without  placing  the  instru- 
ment to  their  ear  or  ears  respective- 


ly. The  device  comprises  a  sound- 
ing-box with  a  suitable  membrane 
and  contact  member  which  will  rest 
against  the  diafram  of  the  telephone, 
when  the  latter  instrument  is  prop- 
erly placed  on  a  spring  table  as 
shown.  This  receiver  to  accommo- 
date the  telephone  instrument  is 
made  resilient  by  placing  the  springs 
under  it,  and  when  this  part  of  the 
apparatus  is  properly  adjusted,  the 
speech  can  be  heard  very  plain  and 
strong  thru  the  trumpet,  all  dis- 
turbing sub-tones  and  by-tones  being 
eliminated  by  the  transmission  of 
the  sound  waves  thru  the  sounding- 
box,  so  the  patentees  claim. 


(No. 


Fan 

to  Angelo 


Unique  Electric 

1,243,238;  issued 
Adamo.) 

An  electric  fan  of  the  portable 
type,  the  object  of  the  invention  be- 


ing to  provide  a  fan  which  will  de- 
liver a  current  of  air  from  all  sides 
or  to  all  quarters  of  a  room  or  apart- 
ment, whereby  a  thoro  circulation 
of  air  may  be  secured  thruout  all 
portions  of  the  room  without  re- 
quiring the  fan  itself  to  be  oscillated 
or  revolved  in  the  ordinary  manner. 
Further,  the  patent'  provides  for  a 
vertical  motor,  and  especially  de- 
vised fan  blades  of  novel  form, 
whereby  the  air  will  not  only  be 
moved  in  a  circular  path,  but  also 
forced  outwardly  for  reliable  and 
efficient  circulation. 


(No. 


Electrical  Punch  Press 

1,242,580;  issued  to  T.  E. 
Murray,  Jr.) 
This  idea  combines  a  mechanical 
punch  press  operation  with  electrical 
means  for  heating  the  piece  of  ma- 
terial to  be  shaped  so  as  to  simplify 
the  process.  The  device  comprises 
two  electrodes  resting  upon  suitable 

r  'in 


II 


Stock 

E.LE.CTP00E 


supports  from  which  they  are  in- 
sulated, as  the  drawing  shows.  The 
stock  material  in  which  a  cup-shaped 
projection  is  to  be  formed,  is  placed 
upon  the  electrodes  so  as  to  cover 
the  central  opening  and  is  secured 
by  clamping  bars  and  bolts.  The 
punch  is  supported  above  the  plates 
in  any  suitable  manner  to  permit 
vertical  motion.  The  stock  plate  be- 
ing clamped  in  position  on  the  elec- 
trodes, the  current  is  establisht  of 
sufficient  strength  to  heat  and  so 
soften  the  portion  of  the  plate  which 
covers  the  central  opening.  The 
punch  is  then  lowered  and  caused 
to  force  the  softened  metal  into  the 
die  opening.  When  the  collar  on 
the  punch  meets  the  two  die  clamps, 
the  current  is  short-circuited  thru 
the  former,  so  that  its  heating  effect 
upon  the  metal  then  ceases,  permit- 
ting the  metal  to  quickly  solidify. 


Electron  Discharge  Bulb 

(No.  1,244,217;  issued  to  Irving 
Langmuir.) 
Electron  discharge  device  suitable 
for  rectifying  alternating  currents, 
etc.,  and  having  an  electrode  con- 
sisting at  least  in  part  of  "thorium," 
and  having  at  a  given  temperature, 
an  electron  emission  per  unit  surface 


materially  greater  than  the  emission 
of  a  refractory  metal,  such  as  Tung- 
sten, at  the  same  temperature  inde- 
pendently of  and  in  the  absence  of 
positive  ionization.  The  patentee 
provides  in  the  glass  envelope  a 
quantity  of  a  vaporizable  reagent 
of  low  vapor  pressure  capable  of 
preventing  the  oxidation  of  "thori- 
um," using  for  this  purpose  an  alkali 
metal  such  as  potassium. 


Secret  Telegraph 

(No.  1,244,477;  issued  to  Patrick  B. 
Delany.) 

The  patentee  has  here  devised  a 
clever  telegraph  sounder  circuit 
whereby  it  is  possible  to  cause  the 
sounder  used  in  public  telegraph 
offices  to  give  "reverse"  signals  and 
in  this  way  to  prevent  any  one  in 
the  vicinity  of  the  instrument  from 
deciphering  the  actual  incoming  mes- 
sage, which  is  taken  from  another 
sounder  close  to  the  operator.  The 
sounder  which  is  connected  to  give 
the  reverse  signals  is  mounted  in 
a   wooden   resonator,    so   that  they 


will  predominate  in  loudness  over 
the  signals  recorded  by  the  main 
sounder."  This  is  accomplisht  by 
providing  a  back  contact  on  the  line 
relay. 


(No. 


Coherer-Protector 

1,242,512;  issued  to  Harry  D. 
Betz.) 

A  clever  arrangement  for  pro- 
tecting wireless  coherers  from  the 
powerful  currents  produced  by  the 
local  transmitting  apparatus  or  other 
nearby  electrical  disturbances.  The 
invention  comprises  a  metallic  case 
for  inclosing  the  coherer  to  exclude 
undesired  waves  therefrom,  two  con- 
tart  members  normally  located  with- 
in the  case  and  adapted  for  con- 
tacting the  coherer  terminals  and 
means  for  withdrawing  the  contact 
members  from  the  metallic  case  a 
sufficient  distance.  To  insure  against 
the  coherer  being  affected  by  Hertz- 
ian waves  or  the  like  during  a  pro- 
tective period,  the  contacting  mem- 
bers are  operated  by  means  of  two 
electric  magnets  at  either  end  of  the 


Mogne/ 


Magnet 


device,  and  which  control  magnets 
may  be  connected  with  the  local 
transmitting  key,  aerial  switch,  etc. 


Improved  Microphone 

(No.  1,244,150;  issued  to  E.  Wein- 
traub.) 

A  microphone  capable  of  carrying 
and  modulating  a  much  larger  cur- 
COPIES  OF  ANY  OF  THE  ABOVE  PATENTS  SUPPLIED  AT  10  CENTS 


rent  than  has  been  possible  in  this 
class  of  apparatus  heretofore.  This 
increase  in  resistance  variation  in 
the  present  device  has  been  affected 
by  raising  the  electrodes  or  current- 
varying  medium  to  a  high  tempera- 
ture, the  passage  of  current  between 
electrodes  being  facilitated  when 
their  temperature,  is  raised,  owing 
to  the  greater  emission  of  electrons. 
These  electrodes  moreover  work  best 
in  a  vacuum  or  in  a  rare  gas  such 
as_  "argon."  Concentric  with  the 
microphone-members,  there  is  placed 
a  cylindrical  coil  forming  an  electric 
heater.  The  ends  of  the  microphone 
electrodes  are  formed  so  that  one 
of  them  may  contain  granules  of 
carbon  for  example,  or  for  a  high 
resistance  microphone — metallic  ox- 
ids,  and  the  end  of  the  other  elec- 
trode is  properly  designed  to  hold 
these  granules  in  place.  Variations 


of  current  thru  an  external  circuit 
are  thus  caused  by  microphonic 
action  at  this  heated  electrode  junc- 
ture, which  current  variations  may 
be  transformed  and  made  to  operate 
a  second  circuit  for  wireless  or 
submarine  signaling  purposes,  etc. 


Thermo-Electric  Generator 

(No.  1,242,499;  issued  to  Hartwell 
W.  Webb.) 
The  principal  object  of  this  in- 
vention is  to  produce  a  thermo-elec- 
tric generator  which  is  particularly 
adapted  for  utilizing  the  waste  heat 
of  the  _  exhaust  gases  of  internal 
combustion  engines.  The  patent  also 
provides  a  thermo-electric  generator 
with  automatic  electric  potential 
regulating  means,  etc.     Instead  of 


soldering  the  two  opposite  metals  of 
the  thermo-couples,  which  are  liable 
to  become  loosened  in  service  and 
thus  reducing  the  efficiency  of  the 
device,  the  present  thermo-couples, 
having  for  instance  iron  as  the  posi- 
tive elements  and  an  alloy  of  nickel 
and  copper  as  the  negative  elements, 
are  interfused  at  their  joints  by  elec- 
tric spot-welding.  This  form  of 
thermo-couple  construction  has  been 
found  to  be  very  efficient.  To  form 
a  generator  unit  of  several  couples, 
and  to  hold  the  elements  in  place, 
a  suitable  impervious  heat-conduct- 
ing and  electric  insulating  binding 
material  is  used,  such  as  a  cement. 
EACH 


January,  1918  ELECTRICAL  EXPERIMENTER  629 

Phoney  Patents 


Under  this  heading  are  publisht  electrical  or  mechanical  ideas  which 
our  clever  inventors,  for  reasons  best  known  to  themselves,  have  as  yet 
mot  patented.  We  furthermore  call  attention  to  our  celebrated  Phoney 
Patent  Offizz  for  the  relief  of  all  suffering  daffy  inventors  in  this  country 
as  well  as  for  the  entire  universe. 

We  are  revolutionizing  the  Patent  business  and  OFFER  YOU  THREE 
DOLLARS  ($3.00)  FOR  THE  BEST  PATENT.  If  you  take  your  Phoney 
Patent  to  Washington,  they  charge  you  $20.00  for  the  initial  fee  and  then 


you  haven't  a  smell  of  the  Patent  yet.  After  they  have  allowed  the  Pat- 
ent, you  must  pay  another  $20.00  as  a  final  fee.  That's  $40,001  WE 
PAY  YOU  $3.00  and  grant  you  a  Phoney  Patent  in  the  bargain,  so  you 
save  $43,001!  When  sending  in  your  Phoney  Patent  application, 
be  sure  that  it  is  as  daffy  as  a  lovesick  bat.  The  daffier,  the  better. 
Simple  sketches  and  a  short  description  will  help  our  staff  of  Phoney 
Patent  examiners   to   issue  a  Phoney   Patent  on  your  invention  In  a 

jiffy. 


PHONEY  PATENT  OFFIZZ 


NO  MAN  S  / 
KEELPQFFJ 


METHOD  OF 
ATTACHING  30/V3 


Prize  Winner.  HUN  KILLER.  My  Plan  For  Finishing  the  5,000,000  Odd  German  Soldiers  Positively  Works!  Conscript  500,000,000  Yankee 
Rats  (100  to  a  Hun);  Then  Manufacture  500,000,000  Electric  Bombs.  Toward  Dawn  of  the  Psychological  Day  Attach  a  Bomb  to  Each  Rat's 
Tall.   The  Aroma  of  Lfmburger  and  Wurst  Attracts  the  Rats:  the  Electric  Time  Fuses  Let  Go;  the  Bombs  Explode  Simultaneously;  Presto! 

No  More  Germans.    Inventor,  Gust  Ekonom,  Springfield,  III. 


ELECTRIC  SNORE  ELIMINATOR.  Who  Is  It  Grumbles  When  the  Ol  d  Man  Snores— Ask  Dad,  He  Knows.  To  Relieve  the  Grumble,  As  Well 
As  the  Snore,  Waste  No  Time  In  Installing  This  Extremely  Simple  Electric  Device  Which  Stops  the  Snore  Instantly  and  Without  Pain.  The 
Annoyee  Pushes  the  Button;  the  Gravity  Cell  Current  Opens;  the  M  agnet  Thus  Releases  the  Snore  Dome.    Simple?    You  Bet!  Inventor, 

Jack  Dodge,  Sydney,  N.  S.  Can. 


630 


ELECTRICAL  EXPERIMENTER 


January,  1918 


QUESTION  BOX 


This  department  Is  for  the  sole  benefit  of  all  electrical  experimenters.  Questions  will  be  answered  here  for  the  benefit  of  all,  but  only 
matter  of  sufficient  Interest  will  be  publlsht.    Rules  under  which  questions  will  be  answered: 

1.  Only  three  questions  can  be  submitted  to  be  answered. 

2.  Only  one  side  of  sheet  to  be  written  on;  matter  must  be  typewritten  or  else  written  in  ink,  no  penciled  matter  considered. 

8.    Sketches,  diagrams,  etc.,  mutt  be  on  separate  sheets.  Questions  addrest  to  this  department  cannot  be  answered  by  mail  free  of  charge. 

4.  If  a  quick  answer  is  desired  by  mail,  a  nominal  charge  of  25  cents  is  made  for  each  question.  If  the  questions  entail  considerable  re- 
search work  or  intricate  calculations  a  special  rate  will  be  charged.  Correspondents  will  be  informed  as  to  the  fee  before  such  questions  are 
answered.    


WIRING  DIAGRAM. 

(874.)  M.  F.  Kelley  of  Meadville,  Pa., 
says : 

Q.  1.  I  wish  to  connect  up  the  instru- 
ments shown  herewith  to  a  small  switch- 
board. Will  you  give  me  a  diagram  of 
the  wiring? 

A.  1.  We  give  complete  wiring  dia- 
gram of  your  instruments. 


Hook-Up  For  Audion  Testing  Switch-Board 
Adapted  to  Laboratory  Requirements. 


RADIUM  EMANATION. 

(875.)  John  Alexander  of  Brownsville, 
Texas,  wishes  to  know : 

Q.  1.  How  can  radium  emanation  be  de- 
tected? 

A.  1.  Radium  emanation  or  that  emit- 
ted by  radio-active  compounds  are  usually 
detected  by  means  of  the  gold-leaf  electro- 
scope, whijch  is  a  very  sensitive  instrument 
for  the  detection  of  these  minute  electronic 
discharges  emitted  by  such  radio-active 
substances. 

Q.  2.  What  is  the  construction  of  a 
spinthariscope? 

A.  2.  The  general  make-up  of  Crooke's 
spinthariscope  is  usually  composed  of 
screen  coated  with  a  very  high-grade 
phosphorescent  zinc  sulfid,  and  a  small  pin 
opposite.  A  short  distance  away  from  the 
phosphorescent  screen  there  is  placed  a 
minute  speck  of  radium,  the  emanations 
from  which  cause  the  zinc  sulfid  to  be- 
come phosphorescent.  The  whole  arrange- 
ment is  placed  in  a  tube,  one  end  of 
which  is  fitted  with  a  magnifying  lens,  so 
as  to  intensify  the  scintillating  particles 
shot  out  from  the  screen. 


EINTHOVEN  GALVANOMETER. 

(876.)  Arthur  Stanley  of  Flushing,  L. 
I.,  wishes  to  know : 

Q.  1.  The  construction  and  operation  of 
an  Einthoven  galvanometer? 

A.  1.  The    general    construction    of  an 


Einthoven  galvanometer  is  shown  in  the 
sketch  herewith.  It  will  be  noted  that  two 
strong  magnet  poles  with  a  very  small  air 
gap  are  used.  The  magnetic  flux  between 
these  poles  is  very  high,  and  is  obtained 
by  the  use  of  two  powerful  electro-magnets 
as  indicated.  These  are  excited  by  a  direct 
current,  usually  obtained  from  a  series  of 
storage  batteries.  The  reason  for  using 
storage  batteries  as  a  source  of  supply  is 


ODD  PHOTOS  WANTED  AT 
$1.00  EACH!  I  ! 

Now  is  the  time  to  make  your 
Kodak  pay  for  itself  in  a  real  practi- 
cal way.  We  are  after  interesting 
photographs  of  out-of-t  he-ordinary 
electrical,  radio  and  scientific  sub- 
jects and  are  willing  to  pay  $1.00  cash 
for  every  one  we  can  use.  Please 
bear  in  mind  that  for  half-tone  re- 
production in  a  magazine,  a  photo- 
graph should  be  particularly  sharp  \ 
and  clear.  Of  course,  if  a  subject 
happens  to  interest  us  particularly 
well,  we  can  have  the  photo  retouched. 
For  the  general  run  of  subjects,  how- 
ever, it  does  not  pay  to  go  to  such 
expense.  Therefore,  please  take  pains 
to  properly  focus  and  expose  your 
pictures.  It  often  happens  that  a 
really  mediocre  subject  well  photo- 
graphed wins  approval  over  an  ex- 
cellent subject  poorly  photographed. 
|  And  don't  send  us  plate  or  film  "nega- 
\  tives" ;  send  unmounted  or  mounted 
|  "prints,"  perferably  a  light  and  a  dark 
j  one. 

i  As  to  what  to  photograph:  Well, 
that's  hard  for  us  to  say.  We  leave 
that  up  to  you,  and  every  reader  now 

I  has  the  opportunity  to  become  a  re- 
porter of  the  latest  things  in  the  realm 
of  Electricity,  Radio  and  Science. 
But,  please  remember — it's  the  "odd, 
novel  or  practical  stunts"  that  we  are 
interested  in.  Every  photo  submitted 
should  be  accompanied  by  a  brief  de- 
scription of  100  to  150  words.  Give 
the  "facts" — don't  worry  about  the 
style.  We'll  attend  to  that.  Enclose 
stamps  if  photos  are  to  be  returned 
and  place  a  piece  of  cardboard  in  the 
envelope  with  them  to  prevent  mutila- 
tion. Look  around  your  town  and 
see  what  you  can  find  that's  interest- 
ing. 

Address  photos  to — Editor  "Odd 
Photos,"  Electrical  Experimenter, 
233  Fulton  Street,  New  York  City. 


that  of  obtaining  a  powerful  unidirectional 
and  constant  current.  The  current  obtained 
from  a  generator  is  by  no  means  uni- 
directional, but  contains  a  series  of  pulsat- 
ing peaks  due  to  the  commutator  action  of 
the  machine. 
In  the   small   air   gap  of  the  magnet 


a  fine  silver-plated  quartz  filament  is  in- 
serted, the  ends  of  which  are  properly  sus- 
pended and  connected  to  the  source  of  cur- 
rent which  is  to  be  measured.  In  one  of  the 
pole-pieces  of  the  electromagnet  a  telescope 
eye-piece  is  inserted,  which  is  used  for 
noting  the  degree  of  displacement  of  the 
quartz  wire  that  takes  place. 

The  principle  of  operation  of  this  device 
is  solely  dependent  upon  the  displacement 
of  the  quartz  filament  in  the  magnetic  field. 
The  degree  of  displacement  of  this  filament 
is  proportional  to  the  amount  of  current 
which  flows  thru  it,  and  the  density  of  the 
magnetic  field  in  which  it  is  placed.  This 


to  measuring  c'ct     <m  Quartz  fiber  fte/d 

Container  .exciting coil 


Storage  Bat  @ 


General  Make-Up  of  Student's  "Einthoven" 
String  Galvanometer. 

type  of  instrument  is  very  sensitive,  and  the 
standard  type  usually  is  so  sensitive  that 
the  filament  will  be  displaced  one  milli- 
meter for  every  one-ten-thousandth  of  an 
ampere.  These  instruments  are  so  sensitive 
that  they  may  be  utilized  for  the  reception 
of  radio  signals. 

These  galvanometers  have  also  been 
utilized  to  a  great  extent  for  the  study  of 
heart  diseases  in  human  beings,  and  a 
description  of  their  use  for  this  purpose  is 
thoroly  described  in  the  May,  1917,  issue  of 
the  Electrical  Experimenter. 


MULTI-LAYER  COILS. 

(877)  D.  L.  Latley,  Westmount,  Can., 
wishes  to  know : 

Q.  1.  Are  one  or  two  coils  used  for  the 
construction  and  use  of  the  Inductances 
mentioned  in  the  article  entitled  "Calcula- 
tion and  Measurement  of  Inductance"  in 
the  September,  1917,  issue  of  the  Experi- 
menter?  If  so,  are  they  the  same? 

A.  1.  You  can  use  as  many  of  these  multi- 
layer coils  in  the  circuit  as  you  wish,  as 
the  electrical  conditions  of  these  coils  are 
just  the  same  as  those  of  the  single  layer 
coils.  There  is  absolutely  no  difference 
between  these  coils  and  the  ones  used  at  the 
present  time. 

Q.  2.  How  is  coupling  varied? 

A.  2.  The  coupling  between  two  multi- 
layer coils  is  varied  in  the  same  manner 
as  that  of  the  single  layer  type,  the  only 
difference  between  the  coils,  both  of  the 
receiving  and  exciting  types,  is  that  the 
multi-layer  coil  contains  several  layers  of 
winding  instead  of  one. 

Q.  3.  Do  all  the  layers  begin  at  the  same 
side  of  coil? 

(Continued  on  page  632) 


January,  1918 


ELECTRICAL  EXPERIMENTER 


631 


Columbia  Graf  onola 

JVlusic  hy  Electricity 

PHE  Grafonola  which  operates  by  electricity  and 
requires  no  winding,  is  rapidly  growing  in  favor. 

The  electric  motor  of  the  Columbia  is  a  marvel  of  accuracy  and 
precision.  It  operates  perfectly  on  any  standard  direct  or  alter- 
nating current;  just  attach  plug  to  socket.  It  holds  the  tone 
true.  No  trouble  about  the  motor  going  "dead"  in  a  Columbia 
Electric  Grafonola.  The  first  time  you  hear  an  electrically 
operated  Columbia  you  will  want  to  own  one. 

You  can  purchase  a  Columbia  Electric  Grafonola  for  $135, 
$145,  $185  or  $240  at  any  store  where  Columbia  Grafonolas  are 
sold.    Convenient  payments  may  be  arranged. 

COLUMBIA  GRAPHOPHONE  COMPANY 

NEW  YORK 


I 


632 


ELECTRICAL  EXPERIMENTER 


January,  1918 


WIRELESS 

The  Government  and  Merchant 
Marine  need  thousands  of  trained 
operators  now,  the  demand  far  ex- 
ceeding the  supply.  Men  are  needed 
urgently  for  the  Naval  Reserve, 
Aviation  &  Signal  Corps,  Marconi 
Co.,  etc. 

Pick  your  rating  before  you  are 
drafted. 

Special  short  code  courses,  Day  or  Eve- 
ning, for  Government  Service.  Students 
from  all  over  the  country.  Send  in  your 
enrollment  today.    Classes  now  forming. 

The  Eastern  Radio  Institute  is  endorsed 
ky  the  U.  S.  Government  6r  Marconi  Co. 

EASTERN  RADIO  INSTITUTE 

899B  Boylston  St.      Boston,  Mass. 


Don't  Fail  to  Read  the  No- 
tice on  the  Front  Cover  Ex- 
plaining how  to  Re -mail  this 
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IT  WILL  AMAZE  YOU! 
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Parachute  and  Model  Bombs  at  same  flight,  drop  them 
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THE  AERO  COMPANY, Dopt  40.  B1NGHAMTON,  N.  Y. 


QUESTION  BOX. 

(Continued  from  page  630) 

A.  3.  It  is  not  necessary  that  all  layers 
of  the  coil  begin  at  the  same  side  of  the 
winding,  but  can  be  a  continuous  winding, 
such  as  those  employed  in  electro-magnets. 


GROUND  BATTERY. 

(878)  Mr.  L.  E.  McQueen,  Elkhart,  Ind., 

asks : 

Q.  1.  Please  explain  to  me  how  I  can 
make  an  earth  battery,  and  what  the  voltage 
will  be,  and  can  I  increase  the  voltage  by 
laying  more  than  one,  and  connecting  them 
together,  as  any  other  cell. 

A.  1.  An  earth  battery  can  be  made  by 
inserting  zinc  and  copper  or  carbon 
electrodes  in  the  earth,  preferably  in  a 
place  where  the  ground  is  very  moist,  so 
that  electro-chemical  action  will  take  place 
between  said  plates ;  thus  producing  an 
electromotive  force  in  the  external  circuit. 

The  voltage  of  such  arrangement  is  very 
low,  usually  below  one  volt.  However,  the 
amperage  of  such  a  cell  can  be  increased 
by  increasing  the  total  exposed  area  of  the 
elements.  They  can  be  increased  by  either 
increasing  the  size  of  the  inserted  elements 
or  by  connecting  several  of  these  elements 
in  parallel. 

This  type  of  cell  is  very  inefficient  and 
very  clumsy.  However,  where  currents  of 
small  magnitude  are  required  at  a  cheap 
cost,  you  will  find  that  such  a  cell  will  be 
of  service. 

It  is  advisable  that  the  space  between 
negative  and  positive  plates  should  be  filled 
with  a  layer  of  charcoal,  which  should 
be  at  all  times  saturated  with  a  weak  acid 
solution  or  a  saturated  solution  of  salt. 
This  will  be  found  to  give  satisfactory 

results.   

ELECTRICAL  QUERY. 

(879)  John  W.  Powers,  Dawson,  111., 
writes  us : 

Q.  1.  A  straight  bar  of  copper,  for 
example,  cutting  across  a  magnetic  field, 
has  a  potential  difference  established  be- 
tween its  ends,  excepting  a  slight  displace- 
ment current  at  the  start.  No  current  would 
flow  until  the  electrical  circuit  was  com- 
pleted. Now  the  question  is :  Does  it 
require  the  same  force  to  move  the  bar 
of  copper  across  the  magnetic  field  when 
the  ends  are  not  connected  and  the  electri- 
cal circuit  was  completed? 

A.  1.  As  soon  as  the  external  circuit  of 
the  revolving  copper  strip  is  closed  when 
moving  in  the  magnetic  field  a  difference 
of  opposite  potential  is  established  in  the 
circuit  which  tends  to  overthrow  the 
originally  produced  electromotive  force. 
This  naturally  produces  a  mechanical  strain 
in  the  revolving  armature  which  necessitates 
a  greater  amount  of  power  to  revolve  it 
at  a  given  speed,  in  order  that  the  desired 
external  electromotive  force  can  be  gener- 
ated. 


STEP-DOWN  TRANSFORMER. 

(880)  S.  C.  Vaughan,  Boonville,  Mo., 
sends  drawings  of  a  rectifier  and  wishes  to 
know : 

Q.  1.  Can  this  arrangement  be  success- 
fully used  to  operate  %"  spark  coil  and 
small  series-wound  motors? 

A.  1.  The  arrangement  of  employing  a 
rectifier  in  conjunction  with  a  step-down 
transformer  is  possible.  The  rectified 
current  thru  the  transformer  would  again 
be  converted  into  a  sinusoidal  current  when 
passing  thru  the  transformer. 

Further,  you  can  operate  satisfactorily  a 
%"  spark  coil  with  this  arrangement  or  run 
a  small  motor,  providing  that  the  step- 
down  transformer  is  sufficiently  large  to 
deliver  the  proper  secondary  current  to 
operate  the  device.  About  2  amperes  will 
be  required  to  run  either  of  the  two  men- 
tioned apparatus. 


TELEGRAPHY,  by  T.  E.  Herbert,  A.  M. 
Inst.  E.  E. ;  cloth  bound,  985  pages,  size 
5  x  7%" ;  Third  Edition  thoroly  revised 
and  enlarged  with  630  illustrations.  The 
Macmillan  Co.,  New  York  City.  Price 
$3.50. 

The  third  edition  of  this  book  far  surpasses 
expectations.  The  work  covers  the  entire  field  and 
the  reviewer  finds  it  impossible  to  describe  in 
detail  the  many  interesting  and  instructive  chapters 
— a  most  concise  and  detailed  exposition  of  the 
telegraph  system  of  the  British  Post  Office. 

Among  the  subjects  treated  we  find: — Funda- 
mental principles  of  magnetism  and  electricity; 
units;  primary  cells;  calculations  in  connection 
with  circuits  and  conductors;  the  resistance  of 
wires;  the  measurement  of  current  and  E.M.F. ; 
battery  testing;  potentiometer  measurements; 
measurement  of  resistance;  single  current  systems 
and  relays;  capacity;  condensers;  the  double  cur- 
rent sounder;  the  differential  duplex;  the  quad- 
ruples; the  wheatstone  automatic  system;  the 
bridge  duplex;  the  wheatstone  A. B.C.:  the  Steljes 
recorder  and  Rebesi  typewriting  telegraph;  the 
Hughes;  the  Baudot;  the  Murray  automatic  and 
Murray  multiplex  systems;  central  battery  tele- 
graphs and  telegraph  switching  systems;  secondary 
cells;  repeaters;  the  test  box  and  protective  de- 
vices; telegraph  testing  and  the  formation  of  spe- 
cial circuits;  construction  of  aerial  lines;  construc- 
tion of  underground  lines,  etc.,  etc. 

Besides  these  numerous  chapters  there  is  an 
Appendix  covering  the  theory  of  Magnetism,  a 
very  lengthy  discourse  on  Chemistry;  Automatic 
Printing  Machines;  Wire  Gages,  etc. 

The  author  has  dealt  in  a  very  increasing  way 
with  all  the  subjects  and  describes  each  apparatus 
and  its  function  in  the  simplest  manner  possible. 
The  standard  method  of  using  these  instruments 
is  explained  in  a  most  up-to-date  manner  in  each 
case,  and  this  work  should  find  a  ready  demand 
from  the  student  as  well  as  the  more  advanced 
worker. 


Text  Book  on  Wireless  Telegraph,  By 
Rupert  Stanley,  B.  A.;  cloth  bound,  340 
pages;  5%  x  8%";  Longmans,  Green  & 
Co.,  New  York  City ;  Price  $2.25.  Second 
Edition. 

Prof.  Stanley's  work  is  one  of  the  best  works 
on  the  subject  of  Radiotelegraphy  as  yet  presented 
to  the  art.  It  fills  a  distinct  want  and  every 
reader  of  this  book  will  certainly  enjoy  the  brilli- 
ant way  in  which  every  subject  is  handled,  and 
moreover,  reap  real  benefit  from  it. 

The  author  has  done  his  work  well  and  in  writ- 
ing the  work  has  always  held  in  mind  the  special 
requirements  of  elementary  students.  Beginning 
with  the  rudimentary  principles,  he  carries  the 
student  on  step  by  step  until  he  knows  each  sub- 
ject thoroly. 

All  the  important  radio  phenomena,  experiments 
and  calculations  are  carefully  explained,  a  series 
of  questions  at  the  end  of  each  chapter  acting  as 
a  review  and  home  examination. 

Many  drawings  and  photos  of  commercial  appa- 
ratus are  incorporated  in  the  work  with  full  ex- 
planation of  each — the  appendix  contains  code 
charts,  call  letters,  rules  and  regulations,  radio 
time  service  and  other  important  data. 

Taken  as  a  whole,  the  work  is  very  complete; 
especially  is  this  true  of  the  chapters  on  undamped 
wave  systems,  which  is  of  special  interest  at  the 
present  time.  Prof.  Stanley  knows  whereof  he 
writes,  having  been  instructor  in  the  subjects  he 
treats  on  for  many  years  in  one  of  the  best  English 
universities. 


WIRELESS  MUSIC  TO  ARMY 
CAMPS. 

Troops  in  many  encampments  within  a 
radius  of  about  100  miles  from  Forty-third 
Street  and  Broadway,  New  York,  recently 
heard  the  strains  of  a  single  phonograph, 
playing  martial  airs  in  a  wireless  tower  at 
that  point. 

Among  the  encampments  connected  with 
the  phonograph  were  those  at  Yaphank, 
Hempstead,  Wrightstown,  Sea  Girt,  Platts- 
burg,  Van  Cortland  Park,  and  many  small 
outpost  stations  where  soldiers  are  guard- 
ing bridges  and  public  works. 

The  experiment  was  conducted  with  a 
phonograph  especially  constructed  for  army 
use  by  Thomas  A.  Edison.  The  idea  is  to 
use  similar  machines  in  France,  where  one, 
placed  in  a  dugout  behind  the  lines  can  send 
"canned"  music  over  the  telephone  to  sol- 
diers in  front  line  trenches  on  a  wide  front. 


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January,  1918 


ELECTRICAL  EXPERIMENTER 


633 


"ELECTRICIAN-RADIO,  U.  S.  N." 

(Continued  from  page  612) 
sea  to  get  his  training,  to  serve  his  ap- 
prenticeship. There  is  no  denying  that  some 
youths  hesitate  to  join  the  Navy  because 
they  find  it  hard  abruptly  to  quit  home  and 
be  stationed  three  to  ten  thousand  miles 
distant.  Suppose,  however,  they  are  sent  to 
a  naval  training  school  only  a  day  or  two 
away  from  their  native  village,  so  that  at 
the  discretion  of  their  Commanding  Officer 
they  may  get  leave  for  a  brief  visit  at  home 
— what  then?  Does  not  that  situation 
banish  all  scruples  of  the  reluctant,  thus 
permitting  them  to  break  into  their  new 
life  more  gradually?  Moreover,  a  man  is 
never  in  the  service  a  month  before  he  is 
ready  and  anxious  to  sail  to  the  end  of  the 
earth  with  the  fleets.  Homesickness  makes 
short  headway  under  the  skin. 

A  training  station  for  sailors  is  in  full 
operation  in  the  unsaltiest  state  in  the 
Union — Minnesota.  And  though  the  men 
from  the  Mississippi  valley  are  especially 
acquainted  with  Dunwoody  Naval  Training 
School,  Minneapolis,  bluejackets  are  there 
from  every  corner  of  the  land,  and  three- 
eighths  of  the  entire  detachment  is  studying 
electricity,  general  and  radio.  When  train- 
ing is  being  given  in  twelve  branches,  and 
there  are  nearly  a  thousand  bluejackets 
being  instructed  at  a  time,  the  relative  con- 
sequence of  the  electrical  crafts  is  at  once 
evident. 

Ensign  Colby  Dodge,  U.S.N.,  Command- 
ing Officer  of  this  remotest  naval  station 
from  the  ocean,  has  from  the  outset  in- 
sisted that  the  electrical  courses  be  given 
extreme  thoroness,  the  same  as  at  the  old- 
establisht  electrical  schools  at  New  York 
and  Mare  Islands  Navy  Yards.  When  the 
offer  of  Dunwoody  to  train  apprentices  was 
accepted  last  summer  by  the  Navy  Depart- 
ment, the  first  move  of  this  state  industrial 
school  was  to  send  its  chief  instructor  in 
electricity  to  that  very  Navy  Yard  in  New 
York,  where  after  weeks  of  concentrative 
observation  at  the  famous  electrical  school 
he  mapt  out  a  course  for  his  prospective 
pupils,  a  plan  of  work  completely  in  ac- 
cord with  naval  stresses,  precedents,  and 
regulations.  He  figured  on  a  wartime 
schedule  of  four  months'  instruction  for 
his  electricians-general,  and  unlike  most  of 
the  other  instructors  who  have  revised  their 
courses  to  three,  five,  or  eight  months,  he 
has  found  his  calculations  about  right.  Now, 
December,  the  first  company  of  one  hun- 
dred Dunwoody-trained  naval  electricians 
has  departed  for  sea  duty,  and  the  winter 
quota  of  apprentices  has  just  begun  to 
wrestle  with  batteries  and  generators.  Radio 
operators,  besides,  have  been  leaving  Dun- 
woody at  the  rate  of  about  thirty  a  week 
since  early  in  September. 

Naturally  it  became  immediately  neces- 
sary to  supplement  the  equipment  already  in 
the  electrical  shops  of  Dunwoody  with 
many  additional  appliances,  some  essentially 
naval  and  some  not.  The  instructor  learned 
at  the  navy  yard  that  the  marine  electrician 
is  up  against  much  apparatus  and  gear 
with  which  the  landsman  is  unfamiliar.  In 
order  that  the  reader  may  obtain  a  precise 
idea  of  what  the  Dunwoody  bluejackets 
study  it  may  be  interesting  to  recount  some 
of  the  mechanism  which  was  specially  in- 
stalled by  the  time  the  men  began  training. 

Upon  reporting  the  urgent  needs  to  the 
Bureau  of  Steam  Engineering  the  follow- 
ing were  received  at  Dunwoody:  Motor 
control  equipment,  signal  devices  such  as  arc 
lights,  incandescent  searchlights,  yard-arm 
blinkers  and  portable  tube  blinkers ;  interior 
communication  devices,  such  as  push  but- 
tons, connection  boxes,  bells,  ship  annuncia- 
tors and  buzzers,  gun  elevating  motors, 
motor  parts,  circuit  breakers,  motor  start- 
ing apparatus,  light  and  power  fixtures  such 
as  deck  fixtures  with  elohes.  ceiling  appur- 


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This  big  size  permits  the  use  of  large  and  comprehensive  illustrations,  plates,  dia- 
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The  completeness  of  the  Cyclopedia  will  be  a  revelation  to 
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until  the  special  advertising  price  of  $19.80  has  been  paid. 
The  regular  price  of  these  pay-raising  books  is  $35.00. 

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A  year's  Consulting  Membership  in  the  American  Technical 
Society — regular  price  $12.00 — will  be  included  with  all  or- 
ders for  a  limited  time.    The  advice  of  an  entire  corps  of 
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See  these  books  for  yourself  before  you  buy.  Remem- 
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tinued  indefinitely.   Send  the  coupon  now.  J 

AMERICAN  TECHNICAL  SOCIETY 

Dept.  E-7441  CHICAGO,  U .  S.  A. 


Read  These  Subjects 
Elements  of  Electricity— 
Electrical  Measurement* 
—Underwriters'  Require- 
ments— Theory.  Calcula- 
tion, Design  and  Con- 
itructlon  of  Generators 
and  Motors  —  Dynamo- 
Electric  Machinery — 
Lighting  Machinery — 
Power  Transmission — 
Electric  Railways — Power 
Stations  —  Switchboard* 
and  Switching  —  Storage 
Batteries — Applied  Blee- 
trn-C'hemlstry  —  Electric 
Elevators — Electrlo  Weld 
Ing  and  Heating  —  Wire 
and  Wireless  Telegraphy. 


*  American  Technical  Society 
Dept.  E-7441  Chicago,  U.S.A. 


Please  send  me  the  Cyclopedia 
t      of  Applied  Electricity  for  seven 
days'  free  examination.  If  I  de- 
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*     in  seven  days,  and  the  balance  at 
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f  Name, 
t  Addrest. 
Reference. 


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634 


ELECTRICAL  EXPERIMENTER 


January,  1918 


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tenances,  distribution  and  junction  boxes, 
and  5-ampere  switches  and  receptacles. 

In  the  Dunwoody  electrical  shop  a  huge 
instrument  board  was  at  once  set  up  bearing 
all  the  small  instruments  and  appliances 
commonly  used  aboard  a  dreadnaught. 
Next  to  this  board  was  hung  a  panel  six 
feet  square,  a  white  panel  with  black  letters 
half  a  foot  high — you've  guesst  it, — the 
eternally  paramount  Ohm's  Law.  That 
formula,  /  equals  E  over  R,  relentlessly 
stares  every  bluejacket  in  the  face  from 
six  to  nine  hours  each  day.  When  he 
leaves  Dunwoody  he  knows  that  cardinal 
law  of  electricity  in  all  its  ramifications, 
knows  it  just  as  certainly  as  he  knows  when 
pay  day  comes  around,  and  that's  almighty 
certain.  No  less  intimately  is  he  acquainted 
with  every  instrument  on  the  adjacent  panel. 
No  bell,  no  buzzer,  no  connection  box,  but 
he  knows  its  anatomy.  He  has  to,  or  his 
coveted  rating  is  denied  him. 

With  the  unprecedented  rush  of  war 
orders  during  the  past  autumn  it  has  not 
been  easy  to  get  quickly  needed  apparatus 
from  manufacturers,  even  by  Government 
direction.  However,  in  fairly  good  time 
for  teaching  the  first  detachment  of  sailor- 
electricians,  Dunwoody  managed  to  obtain 
a  mercury  arc  rectifier,  two  two-horsepower 
shunt  motors,  two  one-eighth  kilowatt 
shunt  generations,  one  variable  speed  direct 
current  motor,  one  automatic  starting  device 
with  push-button  control,  one  variable  speed 
alternating  current  motor,  one  10-kilowatt 
rotary  converter,  one  switchboard  converter, 
one  set  of  voltage  transformers,  two  seven 
and  one-half  K.V.A.  alternators,  one  three- 
panel  switchboard  (D.C.),  one  voltage 
regulator  and  four  auto-transformers.  This 
additional  equipment,  together  with  what 
was  supplied  by  the  Bureau  of  Steam 
Engineering,  rounded  out  a  shop  and  labora- 
tory pretty  well  fitted  to  train  electricians 
worthy  of  Uncle  Sam's  fleets. 

The  Dunwoody  electrical  department  has 
been  peculiarly  fortunate  in  having  among 
other  instructors  two  broadly  trained  ex- 
Navy  men.  Both  enlisted  in  the  Navy  as 
seamen,  second  class.  One  came  out  chief 
electrician  and  the  other  electrician,  first 
class.  They  know  naval  indoctrination,  how 
to  discipline  recruits,  the  advantage  of  Tun- 
ing every  phase  of  their  courses  on  prompt 
schedule. 

"It  is  not  hard  to  get  ahead  in  the  Navy," 
said  one  of  these  men,  who  is  now  director 
of  the  Dunwoody  radio  classes.  "The  great 
mistake  many  bluejackets  make  is  in  try- 
ing persistently,  obtrusively,  to  get  a  "pull" 
with  their  superior  officers.  If  a  man  will 
just  buckle  down  to  his  job  and  forget 
about  bootlicking,  recognition  will  come 
soon  enough.  Nothing  queers  a  man  so 
surely  as  too  much  'pull.' 

"When  the  radio  apprentices  arrive  at 
Dunwoody,"  he  continued,  "I  give  them 
an  entrance  examination  in  common  arith- 
metic and  elements  of  electricity.  If  a 
student  makes  a  fair  mark  he  is  put  in  the 
advanced  class.  If  he  is  weak  on  decimals, 
fractions  and  square  root  he  is  given  a  few 
more  lessons  before  starting  the  related 
work.  The  course  as  outlined  covers  six- 
teen weeks,  half  that  period  devoted  to 
operating  practise  and  the  other  half  to 
classroom,  lectures  and  laboratory.  The 
operating  room  is  fitted  with  tables  and 
head  phones  to  accommodate  one  hundred 
men  at  a  time.  Related  work  includes 
demonstrations  and  lectures  in  theory  of 
motors,  batteries  and  dynamos,  also  the 
theory,  installation,  construction,  operation 
and  repair  of  radio  apparatus.  Each 
student  keeps  a  'log'  book  in  which  he 
writes  all  he  learns  in  class,  and  answers 
twenty  questions  on  the  work  of  each  week. 
An  operating  examination  is  also  given  each 
week,  to  record  sending  and  receiving  ability 
in  words  per  minute.    Unless  a  man  im- 


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January,  1918 


ELECTRICAL  EXPERIMENTER 


635 


proves  steadily  he  is  classed  a  'drone'  and 
marked  down.  If  he  does  not  reach  a 
receiving  speed  of  fifteen  words  a  minute 
after  six  weeks'  training  he  is  relegated  to 
the  'drone  division'  and  gets  special  in- 
struction for  two  weeks.  If  he  still  displays 
no  signs  of  ever  becoming  a  radio  operator 
he  is  send  back  to  Great  Lakes  station  to 
man  a  'deck  swab'  instead  of  a  wireless 
key.  Under  this  system  only  one  or  two 
men  in  a  hundred  have  shown  inaptitude. 

"The  men  are  instructed  on  the  navy  type 
Audion  receiving  sets,  as  well  as  on  the 
measurement  of  wave  lengths  and  the  ad- 
justment of  the  modern  arc  and  spark 
transmitters.  In  the  operating  room  five 
long  tables  are  divided  into  sections  eigh- 
teen inches  deep  by  twenty-four  wide,  each 
section  equipt  with  a  "phone,  jack,  and 
key.  Omnigraphs  are  used  for  sending, 
and  keys  for  hand  sending  to  any  or  all  of 
the  tables  are  mounted  on  the  master  table. 
Three  tables  are  used  for  receiving  only, 
two  for  both  sending  and  receiving.  On 
the  sending  tables  two  students  sitting 
opposite  can  send  to  each  other  indepen- 
dently of  anyone  else.  In  this  way  men  of 
equal  operating  ability  can  be  paired  off  to 
work  together  until  they  attain  ten  or 
twelve  words  a  minute.  They  are  then 
transferred  to  the  receiving  table,  and  upon 
reaching  fifteen  words  go  to  the  'traffic' 
table. 

"Here  each  bluejacket  is  assigned  a  'call 
letter,'  and  is  required  to  carry  on  traffic 
with  the  master  table  in  accordance  with  the 
traffic  laws.  Instead  of  a  buzzer  for  produc- 
ing the  practise  signals  in  the  'phones  a 
high-frequency  generator  is  used.  This  gen- 
erator has  ninety-eight  poles,  and  the  rotor 
which  is  the  field  is  revolved  at  a  speed  suffi- 
cient to  give  a  clear  musical  note  of  about 


600  cycles.  The  head  'phones  are  connected 
directly  thru  the  transmitting  keys  to  the 
stator  coils  of  the  generator,  which  is 
driven  by  a  one-sixth  horse-power  motor. 
The  frequency  as  well  as  the  strength  of 
the  signals  can  be  easily  varied,  so  the 
student  gets  practise  ia  receiving  an  exact 
imitation  of  the  modern  radio  signals  such 
as  are  sent  out  by  undamped  wave  genera- 
tors and  quenched  spark  sets." 

This  scheme  of  instruction  and  the 
arrangement  of  apparatus  have  been  evolved 
by  a  man  who  was  formerly  a  radio  chief 
on  U.  S.  S.  Birmingham,  one  of  the  first 
ships  in  our  navy  to  be  rigged  with  wireless. 
He  has  grown  up  with  the  craft,  the  craft 
which  has  become  literally  a  science  among 
the  most  significant  developments  of  this 
generation.  Dunwoody  radio  men  will  go 
to  sea  ably  tutored.  After  the  war,  either 
in  the  navy  or  in  civilian  appointments,  their 
services  will  continue  to  be  at  a  premium. 

Indeed,  not  a  few  radio  bluejackets  were 
well-trained  operators  before  they  enlisted 
to  aid  their  country  in  the  present  crisis. 
Such  men,  altho  they  gave  up  no  mean 
"bounties"  besides  their  salaries,  realized 
that  the  advanced  instruction  they  could 
obtain  free  in  the  Navy  would  enable  them 
to  get  even  better  jobs  in  later  life. 

I  have  said  that  college  men  are  often 
discovered  amongst  the  recruits.  In  the 
hundred  electricians-general  sent  to  Dun- 
woody  from  the  Mare  Island  Navy  Yard 
and  thru  Captain  Moffett  at  Great  Lakes 
station,  four  have  been  found,  all  graduates 
of  state  universities — California,  Arizona, 
Nevada,  and  Iowa.  As  is  common  with 
men  who  have  gone  thru  college,  their 
lack  of  information  on  practical  problems 
has  been  noticed.  But  these  four  students 
are  well  versed  in  theory,  they  can  teach, 


they  can  assist  excellently  in  the  laboratory, 
with  experiments.  It  has  been  found 
expedient  to  divide  the  electricians  into  four 
sections  of  twenty-five  each,  and  over  each 
section  one  of  these  college  men  is  to  be 
retained  at  Dunwoody,  each  of  the  four 
designated  assistant  instructors  for  the  new 
arrivals. 

That  these  assistants  and  some  other 
experienced  students  who  have  attained 
high  marks  may  not  cease  gaining  electrical 
knowledge,  so  that  eventually  they  can  win 
better  ratings  upon  going  to  sea,  the  chief 
instructor  in  the  department  has  set  aside 
Saturday  mornings  to  give  them  advanced 
work.  As  for  the  preceding  five  days  of 
the  week,  all  electricians  get  six  hours  of 
training  daily,  with  two  two-hour  study 
periods  in  the  Institute  at  night. 

A  general  survey  of  the  Dunwoody  course 
in  electricity  indicates  that  the  work  com- 
prises six  distinctive  parts  :  Magnetism  and 
wiring,  motors  and  generators,  instruments 
and  switchboards,  storage  batteries,  lamps 
and  searchlights. 

To  mention  less  generally  some  of  the 
subjects  covered,  there  may  be  cited  splic- 
ing, soldering,  taping;  annunciators,  con- 
duits and  telephone  circuits ;  micrometers 
and  solenoids ;  motors  and  control ;  gal- 
vanometers, dynamos,  shunt  motors  and 
armatures ;  candlepower,  lighting  circuits, 
Wheatstone's  bridge,  voltmeters,  etc. 

Tho  in  the  electrical  work-shop  at  Dun- 
woody the  bluejacket  has  bench  exercises 
and  learns  to  make  small  apparatus  on 
drill-press  and  lathe,  it  must  not  be  sup- 
posed that  his  instruction  is  confined  solely 
to  that  department.  Before  he  leaves  for 
sea  duty  he  is  made  well  acquainted  with 
the  machine-shop,  gas-engine  laboratory, 
and  forge. 


You  know  I  never  put  anything  on  the  market  until  I'm  sure  it's  the  best  of  its 
kind.  I  wouldn't  risk  losing  the  friendship  of  the  tens  of  thousands  of  you  boys 
who  know  from  experience  with  Erector  and  my  other  toys  that  I  always  put 
the  finest  stuff  into  everything  I  make.   Well !  The 


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ELECTRICAL  EXPERIMENTER 


January,  1918 


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The  new  classes  of  electricians-general 
starting  their  training  at  Dunwoody  in 
December  will  spend  their  first  two  weeks 
mostly  in  the  machine-shop,  learning  to 
operate  big  lathes,  planers,  shapers,  milling 
machines  and  mill-cutters,  even  to  the  radial 
drill-press,  the  grinder,  and  the  emery 
wheels. 

Later,  in  the  gas-engine  department,  the 
bluejacket  electricians  are  familiarized  with 
simple  and  compound  reciprocating  engines, 
with  separators,  traps,  indicators,  tacho- 
meters, pressure  regulators,  and  the  various 
valves,  condensers,  pumps,  gages  and 
revolution  counters.  This  work,  of  course, 
provides  for  much  time  to  be  given  to  the 
practical  operation,  assembly  and  repair  of 
such  mechanism,  lining  up  engines,  over- 
hauling pumps  and  regrinding  valves. 

In  the  longer  period  necessarily  devoted 
to  things  more  intrinsically  electrical,  it  is 
not  possible  to  give  electricians  as  com- 
prehensive a  course  in  gas  and  steam 
engines  as  the  motorboat  pilots  themselves 
are  getting  at  Dunwoody,  nor  in  machine 
tools  and  appliances  as  the  machinists  are 
learning,  nor  yet  in  oxy-acetylene  welding 
and  forging  as  the  blacksmiths  have,  but 
the  general  electrical  students  do  master 
the  rudiments,  and  for  that  reason  they  are 
entitled  to  the  term  "general."  They  are 
without  doubt  the  all-round  handy  men  on 
a  battleship.  In  Commanding  Officer  Colby 
Dodge  of  Dunwoody  Naval  Training  Sta- 
tion, they  have  a  mentor  and  disciplinarian 
who  books  no  rated  man's  despatch  to 
service  in  the  first  line  ships  until  that 
man's  class  record  is  proven  "unqualifiedly 
meritorious." 


THE  X-RAY  ON  THE  BATTLE 
FRONT. 

(Continued  from  page  599) 

after  the  first  exposure.  A  stereoscopic 
plate  holder  for  exceptional  cases,  in  which 
two  exposures  are  better  made  upon  sep- 
arate plates,  finishes  the  equipment. 

Manipulation: — The  distinctive  lead 
marker  is  fastened  to  the  skin  where  it  will 
be  in  contact  with  the  middle  of  the  plate 
while  the  picture  is  made.  The  position  of 
this  is  marked  upon  the  skin  with  an  in- 
delible pencil.  The  plate  is  laid  upon  the 
table  and  the  wire  netting  covers  it.  The 
lead  serial  number  is  invariably  placed  over 
the  lower  external  corner  of  the  plate.  And 
the  same  number  had  better  be  marked 
upon  the  skin  with  an  indelible  pencil.  Lead 
markers  R  and  L  (right  and  left),  will  be 
of  occasional  service.  For  the  thigh  or  any 
part  of  the  head  or  trunk,  the  anti-cathode 
is  set  at  a  distance  of  21  inches  from  the 
plate,  and  is  displaced  laterally  three  inches 
after  the  first  exposure.  For  the  forearm 
or  leg,  the  distance  from  the  anti-cathode 
to  the  plate  is  fourteen  inches  and  the 
lateral  displacement  of  the  anti-cathode  two 
inches.  Each  '/7  inch  subdivision  that  the 
image  of  the  foreign  body  is  displaced  in 
either  case,  corresponds  to  yi  inch  distance 
from  the  plate  to  the  foreign  body  when 
the  exposures  were  made.  If  this  distance 
is  considerable,  we  must  bear  in  mind  the 
fact,  that  the  foreign  body  is  located  in  a 
direction  from  one  image  to  the  correspond- 
ing position  of  the  anti-cathode.  Each  ex- 
posure should  be  made  of  the  same  intensity 
and  duration  as  for  a  single  picture, 
whether  the  exposures  are  made  upon  the 
same  or  separate  plates. 


EXPERIMENTAL  CHEMISTRY. 

(Continued  from  page  626) 

zinc  chlorid  formed,  and  for  this  reason 
it  was  omitted.  In  those  experiments  where 
water  is  employed  solely  as  a  solvent,  it 
does  not  appear  in  the  equation.  Heat  is 
also  left  out  from  equations). 

(2)  PRODUCTS  : — The  products  are 
the  substances  obtained  as  the  result  of  an 
experiment.  These  may  be  one  or  several. 
In  the  experiment  with  iron  and  sulfur, 
there  was  one  product,  iron  sulfid.  The 
equation  may  be  written  : — 


Fe  + 
Factors 


FeS 
Product 


In  other  experiments  two  or  more  products 
may  result  from  a  given  reaction. 

The  symbols  of  the  products  of  an  ex- 
periment are  always  written  on  the  right 
of  the  equation.  The  equality  sign  is  em- 
ployed to  separate  the  factors  from  the 
products.  It  is  much  more  difficult  to 
determine  the  products  of  an  experiment, 
than  to  find  the  factors.  At  the  outset  we 
have  to  accept  statements  that  this  or  that 
substance  is  formed,  as  when  we  are  told 
that  zinc  chlorid  is  the  resulting  product 
from  pouring  hydrochloric  acid  on  zinc. 
We  might,  however,  as  has  been  repeatedly 
done,  have  tested  the  substance,  and  have 
found  the  statement  true. 

In  all  cases  where  we  are  certain  that  a 
given  reaction  takes  place,  the  products 
have  been  at  some  time  ascertained,  and  in 
doing  the  experiments  it  is  well  to  apply 
tests  to  as  many  as  possible.  But  in  a  large 
number  of  cases  we  have  to  accept  the 
statements  of  those  who  have  made  careful 
analysis  of  the  results.  It  thus  becomes 
necessary  at  first  to  memorize  the  factors 
and  the  products.  It  will  be  found  very 
easy,  after  a  little  practise,  to  calculate  the 
most  common  reactions.  If  a  double  de- 
composition takes  place,  the  metal  (or 
positive  part)  of  each  compound  joins  itself 
to  the  non-metal  (or  negative  part)  of  the 
other.  On  mixing  the  solutions  of  silver 
nitrat  and  sodium  chlorid  there  are  formed 
sodium  nitrat  and  silver  chlorid :  AgNOs 
+  NaCl  =  AgCl  +  NaNOs. 

Sometimes  one  metal  sets  free  another 
from  a  compound,  the  former  taking  the 
place  of  the  latter.  In  a  solution  of  silver 
nitrat,  copper  will  displace  the  silver,  deposit 
it,  and  form  copper  nitrat :  Cu  +  2AgNOs 
=  Cu  (N03)2+2Ag. 

Do  not  for  a  moment  think  that  every 
equation  that  you  can  write  stands  for 
a  reaction.  Before  an  equation  is  written 
it  must  be  known  whether  a  given  re- 
action will  take  place.  For  example: 
2NaCl  +  H,0  =  Na20.  +  2HC1  IS  NOT 
CORRECT,  for  on  mixing  the  two  sub- 
stances, there  is  no  such  reaction. 

VARIATION  OF  EQUATIONS: 

There  are  very  few  equations  that  ex- 
press all  that  takes  place  in  an  experiment. 
The  most  they  can  do  is  to  give  the  gen- 
eral average  of  reactions.  ,  Difference  of 
temperature,  strength  of  reagents,  as  well 
as  different  kinds  of  reagents,  all  con- 
tribute greatly  to  the  variation  of  results. 
An  excellent  example  is  the  action  of  nitric 
acid  on  metals.  The  general  equation  is 
8HNO3  +  3M"  =  3M(N08)2  +  4H20  + 
2N02  M"  represents  any  metal,  having  a 
valence  of  two).  But  this  varies  greatly 
with  (1)  temperature  (2)  strength  of  acid, 
and  (3)  different  metals.  Often  two  equa- 
tions are  given  to  express  results  at  dif- 


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ELECTRICAL  EXPERIMENTER 


637 


ferent  temperatures.  Molecular  Equations, 
as  distinguished  from  Atomic  Equations, 
contain  no  free  atoms,  but  have  all  atoms 
combined  as  molecules.  H2  +  O  =  H2O 
is  an  atomic  equation:  2H2  +  02  =  2H20 
is  molecular.  As  the  molecular  composition 
of  most  elements  is  not  known,  it  is  better 
to  write  atomic  equations,  tho  many 
teachers  advocate  and  even  insist  on  writ- 
ing H2y  CU,  02,  never  allowing  the  atom 
to  stand  alone. 

EQUALITY  SIGNS: 
Sometimes  the  two  parts  of  a  reaction 
are    joined    by    an    arrow    (**    or  *») 
instead  of  the  quality  sign  (=)  as  Fe  + 

S  ■  >  FeS.  Often  a  reaction  takes  place 

one  way  under  certain  conditions,  but  under 
other  conditions  the  reverse  reaction 
results,  as  2HI  =  2H  +  2  I,  or  2H  +  2  I 
=  2HI.  The  two  may,  in  fact,  happen  in 
the  same  experiment.  It  is  then  customary 
to  write  it  2HI  ^  2H  +  21  or,  2HI  ^  2H  + 
21,  which  is  read,  hydroiodic  acid  in  equilib- 
rium with  hydrogen  and  iodin.  Conse- 
quently the  reaction  often  does  not  take 
place  completely  in  either  direction,  so  that 
all  three  substances  may  exist  in  equilib- 
rium, side  by  side.  The  ^  or  ^  signs 
always  indicates  a  reversible  reaction.  For 
the  present,  it  is  better  that  the  student 
employ  the  quality  sign  (  =  ). 

VALENCE: 

What  is  Valence?  The  valence  of  an 
element  is  the  combining  or  replacing 
"value"  of  its  atoms.  Valency  is  not  an 
absolute  invariable  property  of  the  element, 
but  is  dependent  on  the  nature  of  the  ele- 
ment combining  and  on  physical  conditions. 

Dumas,  in  1834,  showed  that  1  atom  of 
oxygen  had  the  same  replacing  value  as  2 
atoms  of  hydrogen,  or  2  of  chlorin.  Liebig 
observed  that  hydrogen  and  potassium  had 
the  same  value,  which  was  only  a  third 
that  of  antimony.  Frankland  in  1852  first 
definitely  explained  the  principle  of  valence, 
or  the  saturation  capacity  of  elements. 
Frankland's  valency  theory  was  accepted  by 
chemists  in  1860.  In  1864  Wurtz  and 
Naquet  establisht  the  fact  that  some  ele- 
ments show  more  than  one  valence. 

If  we  compare  a  few  symbols  of  com- 
pounds, we  at  once  observe  a  certain 
numerical  relation  among  their  elements. 
By  way  of  illustration,  HC1,  H20,  H8N, 
H4C.  One  atom  of  chlorin  unites  with  one 
of  hydrogen;  one  of  oxygen  with  2  of 
hydrogen,  one  of  nitrogen  with  3  of  hydro- 
gen, and  one  of  carbon  with  4  of  hydro- 
gen. For  practise  compare  the  following 
in  like  manner  : — 


NaCl, 
NaBr, 
Mai, 
NaF, 


CuCl2, 
CuBr2, 
CuL, 
CuF2, 


BiCh, 
BiBn, 
BiL, 
BiF3, 


SnCli 
SnBri 
Snl4 
SnF4 


We  see  that  sodium  combines  with 
chlorin,  bromin,  iodin,  fluorin,  in  the  atomic 
ratio  1:1.  If  bromin  in  sodium  bromid 
were  to  be  replaced,  by  chlorin,  only  one 
atom  of  chlorin  would  combine  with  one  of 
sodium ;  in  other  words,  chlorin  has  the 
same  replacing  value  as  bromin,  or  as 
iodin  or  fluorin.  Sodium  also  has  the  same 
combining  value  as  has  each  of  the  4  ele- 
ments named,  and  as  has  hydrogen.  Cop- 
per (Cu)  often  has  a  different  value.  Its 
atom  combines  with  2  atoms  of  the  elements 
named.  Its  combining  value  is  twice  as 
great  as  sodium,  or  as  chlorin,  bromin, 
iodin  or  fluorin,  or  hydrogen.  It  has  a 
value  of  2  if  the  others  have  a  value  of  1. 

Valence  has  nothing  to  do  with  the 
strength  or  power  of  affinity.  It  is  the 
combining  (or  replacing)  value.  An  ele- 
ment having  a  valence  of  5  has  that  com- 
bining value  in  the  same  way  (as  an 
analogue)  a  50  cent  piece  has  the  same 
purchasing  value  that  5  dimes  have.    It  can 


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combine  with  or  replace  5  atoms  of  hydro- 
gen or  chlorin. 

The  combining  value  of  the  hydrogen 
atom  is  the  unit  of  valence,  as  this  element 
has  the  smallest  combining  value.  There- 
fore its  valence  is  said  to  be  1.  In  the 
molecule  whose  symbol  is  HC1  the  chlorin 
atom  has  the  same  valence  as  the  hydro- 
gen namely,  1. 

If  sodium  and  chlorin  were  brought  to- 
gether, each  atom  of  sodium  would  combine 
with  one  atom  of  chlorin;  Na  +  CI  = 
NaCl.  If  sodium  and  hydrogen  chlorid 
(hydrochloric  acid)  should  react,  one  atom 
of  sodium  would  displace  one  atom  of 
hydrogen:  Na  +  HC1  =  NaCl  +  H. 

In  magnesium  chlorid  (MgCU)  one  atom 
of  magnesium  cannot  combine  with  a  single 
chlorin  atom,  but  it  picks  out  two  atoms. 
If  the  compound  were  to  be  formed  by  the 
action  of  hydrochloric  acid  on  the  metal, 
the  equation  would  be 


f  Hen  Cl 
Lhcij  ci 


MBh} 


or,  Mg  +  2HC1  =  MgCl2  +  2H.  The 
valence  of  magnesium  is  therefore  2.  In 
the  chlorid  of  bismuth  (BiCls),  the  bismuth 
atom  cannot  combine  with  one  or  two 
chlorin  atoms,  but  is  not  satisfied  with  less 
than  three.  Formed  from  the  elements, 
the  equation  would  be  Bi  -f-  3C1  =  BiCls ; 
if  made  by  the  action  of  hydrochloric  acid, 
Bi  +  3HC1  =  BiCls  +  3H.  Hence  the 
valence  of  bismuth  is  3.  Now  carbon  re- 
quires four  atoms  of  Cl  to  satisfy  its  at- 
traction, and  carbon  chlorid  is  CCU.  If  the 
two  elements  could  unite  directly,  the  fol- 
lowing would  be  the  equation :  C  +  4C1  = 
CCU.  If  hydrogen  could  be  obtained  from 
carbon  and  hydrochloric  acid,  C  +  4HQ 
=  CCh  +  4H  would  represent  such  a  re- 
action.   The  valence  of  carbon  is  4. 

Any  element  which  replaces  hydrogen 
atom  for  atom,  or  any  element  which  com- 
bines with  hydrogen  atom  for  atom,  has  a 
valence  of  1,  is  said  to  be  univalent,  and  is 
also  called  a  monad.  Thus  the  valence  of 
chlorin  in  hydrochloric  acid  is  1.  Note  the 
valence  of  each  of  these  elements,  which 
are  united  with  H:  HBr,  HI,  HF.  Any 
element  combining  atom  for  atom  with  one 
of  these  elements,  F,  Cl,  Br,  I,  is  also  a 
monad.  Note  the  valence  of  the  first  writ- 
ten element  in  these:  NaBr,  KI,  AgCl,  Agl, 
NaF.  Elements  which  require  two  of  these 
atoms  to  make  a  molecule  of  a  compound 
have  their  valence  2,  and  are  called  bivalent 
elements,  or  dyads;  for  example,  calcium 
in  calcium  bromid  (CaBr2).  Note  the  name 
and  valence  of  these  metals :  CuCl2,  HgL, 
MgBr2.  Write  symbols  for  chlorids,  bromids, 
and  iodids  of  these  dyads;  Cd,  Fe,  Ca,  Sr. 
The  elements  whose  atoms  select  three 
atoms  of  a  monad  are  trivalent,  or  triads, 
or  their  valence  is  3 ;  for  example,  As  in 
AsCU.  Write  symbols  of  chlorids,  bromids, 
and  iodids  of  these  triads :  Sb,  Bi,  P,  Fe, 
Cr,  Al.  A  tetrad,  or  tetravalent  element, 
has  its  valence  4.  C  and  Si  are  the  most 
important  tetrads.  A  few  elements  are 
pentads,  that  is  their  valence  is  5 ;  for 
example,  P,  Bi,  Sb.  Try  and  write  symbols 
for  their  pentachlorides.  A  higher  valence 
than  5  is  rare,  though  hexads  and  heptads 
are  known. 

DOUBLE  VALENCE: 

Elements  quite  often  have  more  than  one 
valence;  for  example,  phosphorus  some- 
times combines  with  3,  sometimes  with  4, 
atoms  of  chlorin.  In  the  first  case  it  is  a 
triad  (PCI3),  in  the  second  a  pentad 
(PCls).  The  iron  atom  under  some  con- 
ditions selects  2,  under  others  3,  atoms  of 
chlorin ;  as  FeCl2,  FeCk.  These  are  called, 
{Continued  on  page  640) 


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January,  1918 


ELECTRICAL  EXPERIMENTER 


639 
inning 


The  Boy's  Electric  Toys 


r 


There  have  been  other  electrical  experimental  outfits  on  the  market  thus  far,  but  we  do  not  believe 
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"The  Boy's  Electric  Toys"  is  unique  in  the  history  of  electrical  experimental  apparatus,  as  in  the 
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Student's  chromic  plunge  battery, 
compass-galvanometer,  solenoid,  tele- 
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With  the  instruction  book  which  we  furnish,  one 
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experiments  can  be  performed.  No  other  source  of 
current  is  necessary. 

Moreover,  the  outfit  has  complete  wooden  bases 
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you  have  to  do  is  to  mount  the  various  pieces  by 
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The  outfit  contains  114  separate  pieces  of  mate- 
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at  once. 

The  box  alone  is  a  masterpiece  of  work  on  account 
of  its  various  ingenious  compartments,  wherein  every 
piece  of  apparatus  fits. 

Among  the 
finished  mate- 
rial the  follow- 
No.  EX2002  ing    parts  are 

included: 

,  .amp  socket,  bottle  of  mercury,  core  wire  (two  different  lengths),  a 
bottle  of  iron  filings,  three  spools  of  wire,  carbons,  a  quantity  of  machine  screws,  flexible  cord,  two 


Chromic  salts  for  battery,  lamp  socket, 

spools  of  wire,  ^. 

wood  bases,  glass  plate,  paraffine  paper,  binding  posts,  screw-driver,  etc.,  etc.    The  instruction  book 


is  so  clear  that  anyone  can  make  the  apparatus  without  trouble,  and  besides  a  section  of  the  instruc- 
tion book  is  taken  up  with  the  fundamentals  of  electricity  to  acquaint  the  layman  with  all  important 
facts  in  electricity  in  a  simple  manner. 

All  instruments  and  all  materials  are  well  finished  and  tested  before  leaving  the  factory. 
We  guarantee  satisfaction. 

We  wish  to  emphasize  the  fact    that    anyone    who  goes  through  the  various  experiments 
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The  size  over  all  of  the  outfit  is  14  x  9  x  2J^.  Shipping  weight,  8  lbs. 


yhich 


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ELECTRICAL  EXPERIMENTER 

EXPERIMENTAL  CHEMISTRY. 

(Continued  from  page  638) 

respectively,  ferrous  and  ferric  chlorids. 
Ferrous  always  indicates  the  lower  salt, 
while  ferric  always  indicates  the  higher,  that 
is  the  combining  value  is  2  and  3 
respectively.  Occasionally  elements  have  a 
certain  valence  towards  one  element  and  a 
different  one  towards  another,  but  usually 
varying  conditions  of  formation  govern  this 
peculiarity.  When  hydrogen  and  oxygen 
combine  to  form  water  the  molecule  is 
H20,  and  oxygen  is  a  dyad.  This  valence 
of  oxygen  must  be  regarded  as  being  as 
invariable  as  that  of  hydrogen.  It  is  the 
standard  of  valence  for  negative  or  non- 
metallic  elements. 

HOW  TO  DETERMINE  VALENCE: 

How  can  I  determine  the  valence  of  an 
element  from  the  symbol  of  one  of  its 
compounds?  What,  for  example,  is  the 
valence  of  Mg  in  MgO?  Oxygen  always 
has  two  bonds,  and  hence  Mg  must  have 
the  same  number,  as  there  is  one  atom  of 
each  in  the  symbol.  To  verify  this,  write 
the  number  of  bonds  above  the  element, 
with  plus  sign  for  that  over  the  metal,  and 
minus  for  the  other. 

+  2  —2 
(Mg"  O"). 

In  any  symbol  there  must  be  as  many 
"plus"  bonds  as  "minus."  A  plus  element 
may  not  necessarily  be  a  metal,  so  long  as 
it  is  plus  with  reference  to  the  element  it 
is  combined  with.  There  must  be  no  free 
(or  unsaturated)  bonds;  in  order  to  form 
a  stable  compound  all  must  be  attached. 
This  is  imagined  to  explain  why  atoms  of 
elements  usually  exist  only  in  pairs ;  two 
hydrogen  atoms,  for  example,  attaching 
themselves  together  to  form  a  stable  mole- 
cule, H-H,  or  H2.  Now  HO  is  not  a  correct 
symbol,  for  this  would  leave  one  bond  free, 
H-0-,  which  attracts  another  H  atom  to 
saturate  it,  as  H-O-H,  or  H20.  The  valence 
+  2  —  2 

of  N  in  N2O  may  be  considered  1,  (N'20"), 
that  is,  1  oxygen  atom  with  2  bonds  is  equiv- 
alent to  2  nitrogen  atoms  with  1  bond  each. 
In  N2O3  it  is  3,  since  3  atoms  of  O  with  2 

—6 

bonds  each  equal  6  bonds  (N2Os")  ;  and 
since  2  atoms  have  6  bonds,  1  will  have  3 

+6  —6 

bonds  (N2"  '03"),  or  N  is  here  a  triad. 

Another  good  way  to  determine  the 
valence  of  an  element  in  a  compound,  such 
as  Mg  in  MgO  is  as  follows :  We  know 
that  in  water  hydrogen  has  a  valence  of  1, 
but  an  exponent  of  2  is  used  to  indicate  that 
2  atoms  of  hydrogen  are  required  to  com- 
bine with  1  of  oxygen,  therefore  oxygen 
has  a  valence  of  2.  This  being  the  case  Mg 
must  also  have  a  valence  of  2  in  order  to 
combine  with  the  oxygen.  Likewise  it  can 
be  remembered  that  Chlorin  has  a  valence 
of  1,  because  it  combines  with  1  atom  of 


January,  1918 

Hydrogen  as  in  HC1.  Many  other  ana- 
logues may  be  found  very  useful  for  de- 
termining the  valence  of  any  element  in  a 
compound. 

VALENCE  OF  RADICALS: 

Radicals  as  well  as  elements  have  valence. 
In  the  compound  HNOs  the  NO?  radical 
has  a  valence  of  1,  because  it  combines  with 
1  hydrogen  atom.  In  KNOs  and  NaNOs, 
K  and  Na  are  each  monads,  as  they  replace 
H  atom  for  atom,  and  the  radical  NOs  is 
likewise  univalent.  Copper  is  a  dyad, 
hence  when  it  reacts  with  nitric  acid,  and 
displaces  the  hydrogen,  it  must  displace  2 
atoms,  or  combine  with  2  NOs  radicals,  and 
the  symbol  of  copper  nitrat  is  Cu  (N03)2, 
as  that  of  copper  chlorid  is  CuCla.  Silver 
nitrat  is  AgNOs  and  lead  nitrat  Pb  (NOsH 
because  the  valence  of  silver  is  1  and  of 
lead  is  2,  while  that  of  N03  is  1.  Suppose 
lead  were  to  replace  silver  in  a  solution 
of  silver  nitrat,  the  equation  would  require 
twice  as  many  AgNOa  molecules  as  of  lead 
atoms. 

Pb  +  2  AgNOa  =  Pb(N03)a  +  2Ag 

AgN03l 


Pb+| 

I  AgNOa 


Pb 


NO< 

b 

NO; 


+ 


C3 


EXERCISES  :— In  H2S04  the  S04  radical 
is  united  to  2  hydrogen  atoms,  and  hence 
has  a  valence  of  2.  Potassium  has  the 
same  replacing  value,  and  hence  the  mole- 
cule of  potassium  sulfate  is  K2SOi  not 
KSO4.  The  radical  NH(  has  the  same  re- 
placing value  as  H,  hence  ammonium  sul- 
fate is  (NH4)2S04.  Zinc  is  a  dyad,  and  so 
1  atom  replaced  2  of  hydrogen.  Zinc  sul- 
fate is  ZnS04.  The  reaction  of  zinc  with 
sulfuric  acid  is  Zn+HiS04=ZnS04+2H. 
Triad  elements  uniting  with  dyad  radicals 
give  symbols  as  follows : 

Al"'  and  (SO*)"  is  Al,  (S04)s.  Verifica- 
+6  —6 
tion  :  Al2' ' '  ( S04" )  3.  Write  symbols 
for  these  and  VERIFY  THEM:  Na' 
and  S04,  (NH.)'  and  S04,  Ba"  and  S04, 
Mg"  and  S04,  Fe"  and  S04.  Fe" '  and  S04, 
Cr" '  and  S04,  (The  little  characters  like 
("  ')  means  the  valence  of  the  element  is 
3,  etc.) 

In  phosphoric  acid  (H3P04)  it  is  evident 
that  P04  is  a  triad.  Replace  the  H  with 
Na,  and  we  have  Na3P04.  Give  a  reason 
why  it  would  not  be  NaP04.  Write  sym- 
bols for  K'  and  P04,  Ag'  and  P04,  Ca"  and 
Po4,  ,Ba"  and  P04,  Mg"  and  P04.  Triads 
replace  3  atoms  of  hydrogen,  as  FeP04, 
CrP04.  In  silicic  acid  (H4Si04)  what 
valence  has  the  radical?  Symbolize  silicates 
of  Na',  Pb",  Ca",  Al" ',  and  Srf*. 

The  principle  above  given  enables  us  to 
ascertain  the  valence  of  the  middle  element 
of  a  triad,  for  example  KClOa.  The  val- 
ence of  K  being  1,  of  O  2,  we  have 
■+1  —6 

K'ClOs".   As  there  must  be  as  many  +  as 

— bonds,  CI  will  have  5,  as 

+1+5-6 


TABLE 


Metals  and  Positive  Radicals 


Non-Metal  and  Negative  Radicals 


Monads 

Diads 

Triads 

Tetrads 

Monads 

Diads 

Triads 

Tetrads 

H 

Mg 

As 

Pt 

F 

O 

N 

C 

Na 

Ca 

Sb 

Sn 

CI 

S 

P 

Si 

K 

Sr 

Bi 

Br 

SO, 

B 

Si04 

Ag 

Ba 

Au 

I 

so. 

PO, 

Ntk* 

Pb 

Fe 

NOa 

CO, 

po4 

Cu 

Cr 

NO, 

Ca04 

AsO, 

CH, 
C.H. 

Cd 

Al 

CIO 

C4H40, 

As04 

Zn 
Co 

?g 
Sn 

Fe 

ClOa 
CIo, 
BrO, 
IOs 

CgHaOa 

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January,  1918 


ELECTRICAL  EXPERIMENTER 


641 


K'Cl'Oa".   Take  Pb  (NOk)i  to  find  the  val- 

+2  —12 

ence  of  N.  .Pb(NO.),=PbN20,,  Pb"N20.". 
There  are  10  bonds  left  for  N2  or  5  for  each 

+2  +10—12 

N  (Pb"NrO„").  Find  the  valence  of  N 
in  KN02,  in  KNO„;  of  P  in  Ag3  PO.,  in 
Ca,(PO0». 

Opposite  is  given  a  "table  of  valence," 
which  should  become  familiar  to  the  reader, 
and  it  is  advised  that  they  should  try  and 
memorize  the  main  elements,  and  especially 
the  radicals.  It  is  indispensable,  before 
proceeding  further  in  the  subject,  that  they 
be  able  to  apply  everything  in  this  lesson. 
These  elements  and  radicals  are  arranged 
according  to  the  USUAL  or  more  stable 
valence.  The  valence  of  most  radicals  does 
not  vary,  but  that  of  many  elements  does. 

STRUCTURAL  SYMBOLS  :  —  Molecules 
of  compounds  may  differ  in  three  ways. 
(1)  In  the  KIND  of  atoms  they  contain. 
COa  and  CS2  are  composed  of  carbon  com- 
bined in  one  case  with  oxygen,  in  the  other 
with  sulfur.  (2)  In  the  number  of  atoms 
of  the  same  element.  CO  and  C02  are 
composed  of  the  same  elements,  but  with 
different  proportions  of  oxygen.  Hence 
the  properties  of  the  two  compounds  in 
this  case  are  very  unlike,  as  they  were  in 
the  previous  one.  (3)  In  the  arrangement 
of  atoms  in  the  molecule,  i.e.,  in  MOLEC- 
ULAR STRUCTURE.  GHeO  is  the 
symbol  for  either  methyl  ether  or  ethyl 
alcohol,  two  compounds  of  very  unlike 
properties.  From  their  similarity  of  com- 
position, it  might  be  supposed  that  their 
properties  would  be  the  same,  but  such  is 
not  the  case.  How  can  this  difference  be 
explained,  when  an  exact  analysis  shows 
that  the  percentage  of  carbon,  hydrogen  and 
oxygen  is  the  same  in  both?  It  is  believed 
that  the  molecules  are  differently  made  up 
— that  the  carbon,  hydrogen,  and  oxygen 
atoms  are  arranged  differently  in  the  ether 
and  in  the  alcohol.  That  difference  of  place 
of  atoms  in  molecules  constitutes  MOLEC- 
ULAR STRUCTURE.  Why  is  the  sym- 
bol of  ammonium  hydroxid  written  NfLOH 
and  not  NHsO?  Experiments  show  that 
one-fifth  of  the  hydrogen  bears  a  relation 
to  the  rest  of  the  compound  different  from 
that  which  the  other  four-fifths  bear.  If 
we  add  a  solution  of  ferric  chlorid  (FeCl3) 
to  the  hydroxid,  there  are  formed  Fe(OH)8 
and  NfLCl,  as 

(1)  FeCls+3NH4OH=3NH4Cl+Fe(OH)3 

A.  similar  reaction  takes  place  with 
aluminum,  chlorid,